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UCHIMURA Taro
| Environmental Science and Civil Engineering Division | Professor |
| Department of Civil and Environmental Engineering |
- E-Mail：uchimurataro
mail.saitama-u.ac.jp
Researcher information
■ Degree■ Research Keyword
■ Field Of Study
- Social infrastructure (civil Engineering, architecture, disaster prevention), Geotechnical engineering
- Social infrastructure (civil Engineering, architecture, disaster prevention), Disaster prevention engineering
- Social infrastructure (civil Engineering, architecture, disaster prevention), Safety engineering
- Social infrastructure (civil Engineering, architecture, disaster prevention), Social systems engineering
■ Career
■ Educational Background
- 1997, The University of Tokyo, Japan
- 1997, The University of Tokyo, Graduate School, Division of Engineering
- 1994, The University of Tokyo, The Faculty of Engineering, Japan
- 1994, The University of Tokyo, Faculty of Engineering
Performance information
■ Paper- PREDICTING THE EFFECT OF BED MATERIAL SIZE AND GEOGRID ON LOCAL SCOUR AROUND THE BRIDGE PIER IN CLEAR WATER FLOW CONDITIONS
Negi, D.; Gautam, A. B.; Taro, U.
Geomate Journal, Volume：28, Number：125, First page：1, Last page：10, Jan. 2025, [Reviewed], [Last]
English, Scientific journal - EFFECT OF PVA SHORT FIBERS AND GEOGRID ON THE FLEXURAL STRENGTH OF CEMENT-MIXED SANDY SOIL
Hekmatullah Fahimi; Taro Uchimura; Tufail Ahmad
Geomate Journal, Volume：27, Number：124, First page：32, Last page：39, Dec. 2024, [Reviewed]
English, Scientific journal - A STUDY ON THE EFFECT OF TOE-WING POSITION ON SCREW PILE PERFORMANCE IN COHESIONLESS SOIL.
Sahil, A. W.; Taro Uchimura; Tadashi Maejima; Md Raihanul Kabir
Geomate Journal, Volume：27, Number：122, First page：1, Last page：8, Oct. 2024, [Reviewed], [Last]
English, Scientific journal - RELATIONSHIP BETWEEN AIR PRESSURE AND VOLUMETRIC WATER CONTENT AT STEADY STATE IN RAINFALL-INDUCED LANDSLIDE BASED ON MODIFIED COLUMN TESTS
Avzalshoev Zafar; Uchimura, T.
Geomate Journal, Volume：26, Number：117, First page：52, Last page：59, May 2024, [Reviewed], [Last]
English, Scientific journal - Understanding consolidation theory and Darcy’s law in the study of quasi-saturation in rainfall-triggered landslides for sustainable practices
Zafar Avzalshoev and Taro Uchimura
Sustainability, Volume：Vol. 15, No. 13, First page：10459, 2023 - Effect of Material Composition on Geotechnical Properties—Study on Synthetic Municipal Solid Waste
Vidit Singh and Taro Uchimura
Geotechnics, Volume：2023, 3(2), First page：397, Last page：415, 2023 - Effect of Material Composition on Geotechnical Properties—Study on Synthetic Municipal Solid Waste
Vidit Singh and Taro Uchimura
Geotechnics, Volume：3(2), First page：397, Last page：415, 2023 - Comparison of the Shear Strength of Unsaturated Sandy Soils at Optimal and Residual Moisture Contents
Waqar, A., Uchimura, T., Umar, M.
International Journal of Geomate, Volume：Vol.24, Issue 101, First page：43, Last page：51, 2023 - The Effect of Moisture Content at Compaction and Grain Size Distribution on the Shear Strength of Unsaturated Soils
Waqar, A., Uchimura, T.
Sustainability, Volume：15, First page：5123, 2023 - Permanent Deformation and Breakage Response of Recycled Concrete Aggregates under Cyclic Loading Subject to Moisture Change
Syed Kamran Hussain Shah, Taro Uchimura, Ken Kawamoto
Sustenability, Volume：14, Number：https://doi.org/10.3390/su14095427, 2022 - Risk evaluation and warning threshold of unstable slope using tilting sensor array
Wang Lin, Ichiro Seko, Makoto Fukuhara, Ikuo Towhata, Taro Uchimura, Shangning Tao
Natural Hazards, Volume：https://doi.org/10.1007/s11069-022-05383-y, 2022 - COMPARISON OF THE SHEAR STRENGTH OF UNSATURATED SANDY SOILS AT OPTIMAL AND RESIDUAL MOISTURE CONTENTS
Waqar Ahmad, Uchimura Taro and Muhammad Umar
International Journal of GEOMATE, Volume：Vol.24, Issue 101, First page：43, Last page：51, 2022 - INFLUENCE OF COMPOSITIONAL ANALYSIS ON UNIT WEIGHT OF SYNTHETIC MUNICIPAL SOLID WASTE
Vidit Singh & Taro Uchimura
International Journal of GEOMATE, Volume：Vol.23 Issue 100, First page：134, Last page：141, 2022 - Effect of degree of saturation on particle breakage of recycled concrete aggregate under cyclic loading
Shah S.K.H., Kayani J.Q., Uchimura T. and Kawamoto K
International Journal of GEOMATE, Volume：DOI: https://doi.org/10.21660/2021.81.6171, 2021 - EFFECTS OF PARTICLE SIZE AND TYPE OF AGGREGATE ON MECHANICAL PROPERTIES AND ENVIRONMENTAL SAFETY OF UNBOUND ROAD BASE AND SUBBASE MATERIALS
Hong Nam Thai, Akira Kato, Hoang Giang Nguyen, Tien Dung Nguyen, Ton Kien Tong, Van Tuan Nguyen, Taro Uchimura, Takeshi Maki, and Ken Kawamoto
International Journal of GEOMATE, Volume：Vol.20, Issue 78, First page：148, Last page：157, 2021 - Instrumented model slopes to investigate the effects of slopeinclination on rainfall-induced landslides
Gallage, Chaminda, Abeykoon, Tharindu, & Uchimura, Taro
Soils and Foundations, Volume：61(1), First page：160, Last page：174, 2021 - Experimental study on the relationship between the velocity of surface movements and tilting rate in pre-failure stage of rainfall-induced landslides
Jiren Xie; Taro Uchimura; Zain Maqsood; Jingli Tian
Sensors, Volume：21, First page：5988, 2021
Scientific journal
DOI：https://doi.org/10.3390/s21185988
DOI ID：10.3390/s21185988, ORCID：99791992 - Mechanism and future risk of slope instability induced by extreme rainfall event in Izu Oshima Island, Japan
Ikuo Towhata; Satoshi Goto; Shigeru Goto; Takeshi Akima; Junya Tanaka; Taro Uchimura; Gonghui Wang; Hiroshi Yamaguchi; Shogo Aoyama
Natural Hazards, Volume：105, Number：1, First page：501, Last page：530, Jan. 2021
Springer Science and Business Media LLC, Scientific journal
DOI：https://doi.org/10.1007/s11069-020-04321-0
DOI ID：10.1007/s11069-020-04321-0, ISSN：0921-030X, eISSN：1573-0840 - Application and verification of a multivariate real-time early warning method for rainfall-induced landslides: implication for evolution of landslide-generated debris flows
Zongji Yang; Liyong Wang; Jianping Qiao; Taro Uchimura; Lin Wang
Landslides, Volume：17, Number：10, First page：2409, Last page：2419, Oct. 2020
Rainfall-induced landslides are a frequent and often catastrophic geological disaster, and the development of accurate early warning systems for such events is a primary challenge in the field of risk reduction. Understanding of the physical mechanisms of rainfall-induced landslides is key for early warning and prediction. In this study, a real-time multivariate early warning method based on hydro-mechanical analysis and a long-term sequence of real-time monitoring data was proposed and verified by applying the method to predict successive debris flow events that occurred in 2017 and 2018 in Yindongzi Gully, which is in Wenchuan earthquake region, China. Specifically, long-term sequence slope stability analysis of the in situ datasets for the landslide deposit as a benchmark was conducted, and a multivariate indicator early warning method that included the rainfall intensity-probability (I-P), saturation (Si), and inclination (Ir) was then proposed. The measurements and analysis in the two early warning scenarios not only verified the reliability and practicality of the multivariate early warning method but also revealed the evolution processes and mechanism of the landslide-generated debris flow in response to rainfall. Thus, these findings provide a new strategy and guideline for accurately producing early warnings of rainfall-induced landslides.
Springer Science and Business Media Deutschland GmbH, English, Scientific journal
DOI：https://doi.org/10.1007/s10346-020-01402-w
DOI ID：10.1007/s10346-020-01402-w, ISSN：1612-5118, SCOPUS ID：85083215873 - Physical model experiments on water infiltration and failure modes in multi-layered slopes under heavy rainfall
Junfeng Tang; Uchimura Taro; Dong Huang; Jiren Xie; Shangning Tao
Applied Sciences (Switzerland), Volume：10, Number：10, First page：3458, May 2020
To assess the influence of an intermediate coarse layer on the slope stability during heavy rainfall, knowledge about water movement and how slope failure occurs is important. To clarify the characteristics of water infiltration in a multi-layered slope and assess its influence on the slope failure modes, eight groups of physical slope models were investigated. It was found that the unsaturated hydraulic conductivity in the coarse layer (5.54 x 10-6 cm/s) was much lower than that of the fine layer (1.08 x 10-4 cm/s), which resulted in the capillary barrier working at a lower water content. Intermediate coarse layers embedded between finer ones may initially confine the infiltration within the overlying finer layers, delaying the infiltration and eventually inducing a lateral flow diversion in the inclined slope. Two different failure modes occurred in the model experiments: surface sliding occurred at the toe in the single-layer slope group and piping occurred at the toe in the multi-layered slope as the rainfall water accumulated, was diverted along the interface, and then broke through in the downslope direction of the intermediate coarse layer. The lateral flow diversion caused by the capillary barrier and the tilt angle may be the major factors influencing the difference of the failure modes. The result also revealed that the coarser layers may have negative effects on the slope stability.
MDPI AG, English, Scientific journal
DOI：https://doi.org/10.3390/app10103458
DOI ID：10.3390/app10103458, ISSN：2076-3417, SCOPUS ID：85085689384 - Predicting the surface tilting behavior based on slope tilting measurements in shallow landslides
Shifan Qiao, Chaobo Feng, Pengkun Yu, Junkun Tan, Taro Uchimura, Lin Wang, Junfeng Tang, Quan Shen, Jiren Xie
Sensors, 2020 - Water movement and deformation in unsaturated multi-layered slope under heavy rainfall
Tang Junfeng, Uchimura Taro, Tao Shangning, Huang Dong, Xie Jiren
International Journal of GEOMATE, Volume：Vol.19, Issue 71, First page：174, Last page：181, 2020 - A new prediction method for the occurrence of landslides based on the time history of tilting of the slope surface, Landslides
Jiren Xie, Taro Uchimura, Gonghui Wang, Quan Shen, Zain Maqsood, Canrong Xie, Jiapeng Liu, Weikai Lei, Shangning Tao, Pan Chen, Hongyuan Dong, Guoxiong Mei, Shifan Qiao
Landsides, Volume：17, First page：301, Last page：312, 2020 - Estimation of the instability of slope surface layer by elastic wave attenuation changing with soil moisture and deformation
Shangning Tao, Taro Uchimura, Junfeng Tang and Makoto Fukuhara
International Journal of GEOMATE, Volume：Vol.18, Issue 70, First page：81, Last page：87, 2020 - Predicting the sliding behavior of rotational landslides based on the tilting measurement of the slope surface
Jiren Xie, Taro Uchimura, Gonghui Wang, Hemakanth Selvarajah, Zain Maqsood,Quan Shen, Guoxiong Mei, Shifan Qiao
Engineering Geology, Volume：269, 2020 - A relationship between displacement and tilting angle of the slope surface in shallow landslides
Jiren Xie, Taro Uchimura, Pan Chen, Jiapeng Liu, Canrong Xie, Quan Shen
Landslides, Volume：16(6), First page：1243, Last page：1251, 2019 - Clarifying hydrological mechanism and its thresholds for rainfall-induced landslide: in situ monitoring big data to unsaturated stability analysis
Zongji Yang, Huan Cai, Dong Huang, Taro Uchimura, Xiaoqin Lei, Honglin Tian, Jianping Qiao
Bulletin of Engineering Geology and the Environment, Volume：78, First page：2139, Last page：2150, 2019 - Evaluation of Soil Moisture and Shear Deformation Based on Compression Wave Velocities in a Shallow Slope Surface Layer
Shangning Tao, Taro Uchimura, Makoto Fukuhara, Junfeng Tang, Yulong Chen and Dong Huang,
Sensors, Volume：19(15), First page：3406, 2019 - Development of elastic wave velocity threshold for rainfall-induced landslide prediction and early warning
Yulong Chen, Muhammad Irfan, Taro Uchimura, Yang Wu, Fangwei Yu
Landslides, Volume：16(5), First page：955, Last page：968, 2019 - A relationship between displacement and tilting angle of the slope surface in shallow landslides
Jiren Xie, Taro Uchimura, Pan Chen, Jiapeng Liu, Canrong Xie, Quan Shen
Landslides, Volume：Published Online 28 Jan 2019, 2019 - Shear deformation and failure of unsaturated sandy soils in surface layers of slopes during rainwater infiltration
Yulong Chen, Kapila R. Withanage, Taro Uchimura, Wuwei Mao, Wen Nie
Measurement, Volume：149, 2019 - Elastic wave velocity monitoring as an emerging technique for rainfall-induced landslide prediction
Yulong Chen, Muhammad Irfan, Taro Uchimura, Guanwen Cheng, Wen Nie
Landslides, Volume：Vol.15, First page：1155, Last page：1172, 2018 - An Early Warning Monitoring of Earthquake-induced Slope Failures by Monitoring Inclination Changes in Multi-Point Tilt Sensors
L. Wang, S. Nishie, L. Su, H. Yamaguchi, S. Yamamoto, T. Uchimura and S.N. Tao
Lowland Technology International, International Association of Lowland Technology (IALT), Volume：19, Number：4, First page：251, Last page：256, 2018 - Features of elastic wave propagation in soil with different exciter energy
Shangning Tao, Taro Uchimura, Junfeng Tang, Jiren Xie, Yulong Chen, Dong Huang
Proc. of The 7th China-Japan Geotechnical Symposium, First page：311, Last page：315, 2018 - A new method to Evaluate the initiation of landslide using tilt measurements
Xie Jiren, Taro Uchimura
Proc. of The 7th China-Japan Geotechnical Symposium, First page：392, Last page：395, 2018 - High seismic performance of preloaded and prestressed geotextile-reinforced soil structures
Masahiro Shinoda; Taro Uchimura; Yoshihisa Sugimura; Fumio Tatsuoka; Masaru Tateyama
ISRM International Symposium 2000, IS 2000, 2018
Only a limited number of geotextile-reinforced soil (GRS) structures have been constructed as important permanent structures supporting heavy load, such as bridge abutments and piers, due to their relatively low vertical stiffness. To alleviate this problem, the preloaded and prestressed (PLPS) reinforced soil method has been proposed. To evaluate the seismic stability of PLPS GRS structures, a series of shaking table tests of small models were performed. It is shown that the seismic stability of PLPS GRS structures becomes very high by proper preloading and prestressing. Resonance of the structure to seismic load can be avoided by maintaining a high natural frequency of the structure with a high prestress. A measures to maintain a sufficiently high prestress during strong shaking is presented.
International Society for Rock Mechanics, English, International conference proceedings
SCOPUS ID：85053884067 - Distributed tilt sensors for an early warning monitoring of Earthquake-induced landslides and slope failures
Lin Wang; Shunsaku Nishie; Taro Uchimura; Dong Huang
Proceedings of the 7th China-Japan Geotechnical Symposium: New Advances in Geotechnical Engineering, CJGS 2018, Volume：2018-, First page：347, Last page：353, 2018
An early warning monitoring system is one of the most effective ways to reduce disasters induced by slope instabilities. The 2008 Ms 8.0 Wenchuan earthquake that occurred in Sichuan province, China, induced more than 197, 000 slope failures and landslides. Otherwise, there are more than 270, 000 potential slope failures in Japan. To reduce vulnerability to such slope and landslide hazards, a low cost that compared to a traditional instrumentation of inclinometers and extensometer, and an effective early warning system becomes important. For this purpose, a new monitoring method of distributed tilt sensors developed by authors, was adopted by local government of Japan and China This is a newly simple multi-point method of monitoring landslides and slope failures, with the intention of developing an early-warning system. Surface tilt angles of a slope are monitored using this method, which incorporates a Micro Electro Mechanical Systems (MEMS) tilt sensor and a volumetric water content sensor. This system was applied to many landslides and slopes in Japan and China recently. In several case studies, including a slope failure test conducted on a natural slope using artificial heavy rainfall, the system detected distinct tilt behavior in the slope in pre-failure stages. Based on these behaviors and a conservative approach, it is proposed that a precaution for slope failure be issued at a tilting rate of 0.01°/hr., and warning of slope failure issued at a rate of 0.1°/hr. (Uchimura et al.2015). The development of this system can occur at a significantly reduced cost compared with current and comparable monitoring methods.
China Communications Press Co., Ltd., English, International conference proceedings
SCOPUS ID：85049014814 - Detection of water infiltration and deformation of unsaturated soils by elastic wave velocity
Yulong Chen, Taro Uchimura, Muhammad Irfan, Dong Huang, Jiren Xie
Landslides, Volume：published online, 2017 - Unsaturated hydro-mechanical behaviour of rainfall-induced mass remobilization in post-earthquake landslides
Zongji Yang, Jianping Qiao, Taro Uchimura, Lin Wang, Xiaoqin Lei, Dong Huang
Engineering Geology, Volume：Vol. 222, First page：102, Last page：110, 2017 - Unsaturated hydro-mechanical behaviour of rainfall-induced mass remobilization in post-earthquake landslides
Zongji Yang, Jianping Qiao, Taro Uchimura, Lin Wang, Xiaoqin Lei, Dong Huang
Engineering Geology, Volume：Vol. 222, First page：102, Last page：110, 2017 - A multi-source early warning system of MEMS based wireless Monitoring for rainfall-induced landslides
Zongji Yang, Jianping Qiao, Dong Huang, Honglin Tian, Xiaoqin Lei, Taro Uchimura
Applied Sciences, Volume：Vol. 7, No. 12, First page：1234, 2017 - Detection of water infiltration and deformation of unsaturated soils by elastic wave velocity
Yulong Chen, Taro Uchimura, Muhammad Irfan, Dong Huang, Jiren Xie
Landslides, Volume：Vol. 14, First page：1715, Last page：1730, 2017 - Experimental Identification on Thresholds for Early Warning of Rainfall-induced Failure on Fractured Slopes after Giant Earthquake
Yang, Z.-J, Qiao, J.-P., Huang, D., Uchimura, T., Wang, L.
Sains Malaysiana, Volume：46, Number：doi:10.17576/jsm-2017-4611-02, First page：2029, Last page：2034, 2017 - Gas transport parameters and thermal properties of construction demolition waste and recycled materials under air-dried condition
Mohd Redzuan, B.M.S., A. Matsuno, T. Saito, T. Uchimura, S. Asamoto, and K. Kawamoto
第14回地盤工学会関東支部発表会 (Geo Kanto 2017), First page：353, Last page：356, 2017 - Effects of Soil Deformation and Saturation on Elastic Wave Velocities in relation to Prediction of Rain-Induced Landslides
Muhammad Irfan, Taro Uchimura, Yulong Chen
Engineering geology, Volume：Vol. 230, First page：84, Last page：94, 2017 - Comparison of direct and indirect measured soil-water characteristic curves for a silty sand
T. Abeykoon, R.S. Udukumburage, C. Gallage and T. Uchimura
International Journal of GEOMATE, Volume：13, Number：9, First page：9, Last page：16, 2017 - 斜面の多点計測による監視と崩壊の早期警報
内村太郎・王林
地盤工学会誌, Volume：第65巻8号, Number：8, First page：4, Last page：7, 2017
ISSN：1882-7276, J-Global ID：201702262432480384 - Proposed early warning system of slope failure by monitoring inclination changes in multi-point tilt sensors
Lin Wang; Shunsaku Nishie; Ling Su; Taro Uchimura; Shangning Tao; Ikuo Towhata
ICSMGE 2017 - 19th International Conference on Soil Mechanics and Geotechnical Engineering, Volume：2017-, First page：2215, Last page：2218, 2017
A low-cost and simple method of monitoring rainfall-induced landslides is proposed, with the intention of developing an early-warning system. Surface tilt angles of a slope are monitored using this method, which incorporates a Micro Electro Mechanical Systems (MEMS) tilt sensor and a volumetric water content sensor. In several case studies, including a slope failure test conducted on a natural slope using artificial heavy rainfall, the system detected distinct tilt behavior in the slope in pre-failure stages. Based on these behaviors and a conservative approach, it is proposed that a precaution for slope failure be issued at a tilting rate of 0.01°/h, and warning of slope failure issued at a rate of 0.1°/h. The development of this system can occur at a significantly reduced cost (approximately one-third) compared with current and comparable monitoring methods. Given the cost reduction, slopes can be monitored at many points, resulting in detailed observation of slope behaviors, but the potentially large number of monitoring points for each slope does induce a financial restriction. Therefore, the selection of sensor positions needs to be carefully considered for an effective early warning system.
19th ICSMGE Secretariat, English, International conference proceedings
SCOPUS ID：85045460498 - Shaking table tests on mitigation of liquefaction vulnerability for existing embedded lifelines
Masahide Otsubo; Ikuo Towhata; Toshihiko Hayashida; Masato Shimura; Taro Uchimura; Bangan Liu; Damoun Taeseri; Bertrand Cauvin; Hadrien Rattez
SOILS AND FOUNDATIONS, Volume：56, Number：3, First page：348, Last page：364, Jun. 2016, [Reviewed]
The 2011 off the Pacific Coast of Tohoku Earthquake caused significant damage to underground sewage lifelines in the Tokyo Metropolitan area. The importance of the earthquake- and liquefaction-resistance of embedded pipelines was recognised, as a significant amount of time passed before the commencement of temporary operations was resumed. One of the lessons learned was the liquefaction vulnerability of relatively inexpensive structures such as embedded sewage pipelines whose seismic resilience is important for the robustness and quick repair of urban infrastructures. The same problem is likely to occur in other regions where strong earthquakes are expected in the near future. Despite the urgency of this situation, it is not possible these days to excavate pipes and improve backfills quickly due to financial limitations. Hence, less expensive measures, such as mechanical constraints, the partial injection of grout, the installation of drain pipes, and the insertion of sheath pipes, are proposed in this paper. In the present study, shaking model tests were conducted for the purpose of validating those measures by which retrofitting may be achieved at reduced construction costs and in a shorter time frame. Through the tests, the proposed measures exhibited the satisfactory performance of mitigating liquefaction-induced damage to sewage pipelines. The results of the shaking table tests on different mitigation measures were discussed considering their practical applications. (C) 2016 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.
JAPANESE GEOTECHNICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1016/j.sandf.2016.04.003
DOI ID：10.1016/j.sandf.2016.04.003, ISSN：0038-0806, Web of Science ID：WOS:000380748400003 - Development and performance evaluation of disk type piezoelectric transducer for measurement of shear and compression wave velocities in soil
Muhammad Irfan, Taro Uchimura
Journal of Earthquake Engineering, Volume：Published online: 22 Sep 2016, 2016 - Precaution and early warning of surface failure of slopes using tilt sensors
Taro Uchimura; Ikuo Towhata; Lin Wang; Shunsaku Nishie; Hiroshi Yamaguchi; Ichiro Seko; Jianping Qiao
SOILS AND FOUNDATIONS, Volume：55, Number：5, First page：1086, Last page：1099, Oct. 2015, [Reviewed]
A simple monitoring method for the early warning of rainfall-induced landslides is proposed. Tilting angles in the surface layer of the slope are mainly monitored in this method. In the first stage of this study with a scaled model slope, distinct behaviors were observed in the tilt angles monitored on the surface of the slope prior to failure. Hence, a set of equipment has been developed for practical use, which is equipped with a Micro Electro Mechanical Systems (MEMS) tilt sensor and a volumetric water content sensor. An optional arrangement of tilt sensors has also been developed in order to investigate the deformation of the deeper layers. These sets of equipment have been deployed at several slope sites in Japan and China, and their performances have been recorded. Slope failure tests were also conducted on a natural slope by applying artificial heavy rainfall. The developed system detected distinct behaviors in the tilting angles at these sites in the pre-failure stages. Considering the behaviors of tilting monitored on the surfaces of these slopes, it is proposed that a precaution be issued at a tilting rate of 0.01 degrees per hour and a warning be issued at a tilting rate of 0.1 degrees per hour, to be on the conservative side. (C) 2015 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.
JAPANESE GEOTECHNICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1016/j.sandf.2015.09.010
DOI ID：10.1016/j.sandf.2015.09.010, ISSN：0038-0806, Web of Science ID：WOS:000363433500014 - Real-time prediction of hydraulic conditions in slope ground based on monitoring data of moisture contents
Taro Uchimura; Wang Lin
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability, First page：1017, Last page：1020, 2015
Moisture content is the most important factor affecting the stability of slopes against heavy rainfall events. In most of risk management methods for slope disasters, the rainfall intensity is used as the dominant index to evaluate the probability of failure events in an area. However, each slope should have individual hydraulic characteristics, and its probability of failure should be different from other slopes even under the same rainfall conditions. Some slope may contain a lot of water quickly after starting of rainfall, while some slope may show quick drainage after it stopped to rain. Such individual properties of each slope can be evaluated by observing the time histories of moisture contents in the slope ground together with rainfall records. In this paper, an attempt to establish a mathematical model on drainage process in a slope ground is reported. There is a simple relationship between the current moisture contents and the drainage rate of moisture, although this relation is affected by the adjacent rainfall intensity. The drainage properties of a slope can be evaluated by watching the behaviors of moisture contents at rainfall events with relatively low intensity. And the model parameters obtained by such weak rainfall events can be used to estimate the drainage rate after heavy rainfall events with some correction of the parameters, by using real time monitoring system.
Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, English, International conference proceedings
DOI：https://doi.org/10.3208/jgssp.JPN-038
DOI ID：10.3208/jgssp.JPN-038, SCOPUS ID：84971468493 - Shaking Model Tests on Liquefaction Mitigation of Embedded Lifeline
Ikuo Towhata; Masahide Otsubo; Taro Uchimura; Masato Shimura; Bangan Liu; Toshihiko Hayashida; Damoun Taeseri; Bertrand Cauvin
PERSPECTIVES ON EARTHQUAKE GEOTECHNICAL ENGINEERING: IN HONOUR OF PROF. KENJI ISHIHARA, Volume：37, First page：311, Last page：341, 2015, [Reviewed]
The gigantic earthquake in 2011 caused significant damage in lifeline in the Tokyo Metropolitan area. In particular, the damage was significant in recent artificial islands where liquefaction affected embedded sewage pipelines profoundly. The encountered problem is that the entire subsoil liquefied in addition to loose backfill soils, and that the damage of branch lines introduced liquefied sand into trunk sewage lines, leading to difficult problem of sand clogging. Moreover, the same problem is expected to occur in other areas where strong earthquakes are expected in near future. The present paper addresses the ongoing model tests by which a variety of mitigation measures for sewage pipelines are examined. In the regions where future earthquake is expected, it is not possible to excavate pipes and reconstruct backfills now because of financial limitations. To cope with this situation, less expensive measures such as mechanical constraint, partial injection of grout, or limited installation of drainage measures are studied.
SPRINGER, English, International conference proceedings
DOI：https://doi.org/10.1007/978-3-319-10786-8_12
DOI ID：10.1007/978-3-319-10786-8_12, Web of Science ID：WOS:000380537200012 - Monitoring of unstable slopes by MEMS tilting sensors and its application to early warning
Ikuo Towhata; Taro Uchimura; Ichiro Seko; Lin Wang
INTERNATIONAL SYMPOSIUM ON GEOHAZARDS AND GEOMECHANICS (ISGG2015), Volume：26, 2015, [Reviewed]
The present paper addresses the newly developed early warning technology that can help mitigate the slope failure disasters during heavy rains. Many studies have been carried out in the recent times on early warning that is based on rainfall records. Although those rainfall criteria of slope failure tells the probability of disaster on a regional scale, it is difficult for them to judge the risk of particular slopes. This is because the rainfall intensity is spatially too variable to forecast and the early warning based on rainfall alone cannot take into account the effects of local geology, hydrology and topography that vary spatially as well. In this regard, the authors developed an alternative technology in which the slope displacement/deformation is monitored and early warning is issued when a new criterion is satisfied. The new MEMS-based sensor monitors the tilting angle of an instrument that is embedded at a very shallow depth and the record of the tilting angle corresponds to the lateral displacement at the slope surface. Thus, the rate of tilting angle that exceeds a new criterion value implies an imminent slope failure. This technology has been validated against several events of slope failures as well as against a field rainfall test. Those validations have made it possible to determine the criterion value of the rate of tilting angle to be 0.1 degree/hour. The advantage of the MEMS tilting sensor lies in its low cost. Hence, it is possible to install many low-cost sensors over a suspected slope in which the precise range of what is going to fall down during the next rainfall is unknown. In addition to the past validations, this paper also introduces a recent application to a failed slope in the Izu Oshima Island where a heavy rainfall-induced slope failure occurred in October, 2013.
IOP PUBLISHING LTD, English, International conference proceedings
DOI：https://doi.org/10.1088/1755-1315/26/1/012049
DOI ID：10.1088/1755-1315/26/1/012049, ISSN：1755-1307, Web of Science ID：WOS:000361429800049 - Low-cost and simple early warning systems of slope instability
Ikuo Towhata; Taro Uchimura
Landslides: Global Risk Preparedness, First page：213, Last page：225, Oct. 2013, [Reviewed]
In the projects of IPL 139 (Development of low-cost early warning system of slope instability for civilian use) and IPL 127 (Development of low-cost detector of slope instability for individual use), a low-cost and simple monitoring method for early warning of landslides was proposed. A wireless sensor unit which is equipped with a MEMS (Micro Electro Mechanical Systems) tilt sensor and a volumetric water content sensor was developed and tested on eight real slopes in Japan and China. The sensor unit measures rotation angle on a slope surface by the tilt sensor. In order to examine its relevance, model tests were conducted, and it was confirmed that rotation of the slope surface was observed 30-50 minutes before failure. A similar trend was also observed in a real slope. This could be useful as a signal for early warning. The authors also developed a new sensor device named the 'Miniature Ground Inclinometer'. It is a long stainless steel pipe with a small diameter, which is equipped with MEMS tilt sensors. By installing it vertically into the slope ground, the array of tilt sensors detects the lateral displacement of the ground. It can be directly inserted into the slope ground together with the sensor units inside by using a small hammer. This allows low cost and quick installation of the device in landslide sites.
Springer-Verlag Berlin Heidelberg, English, In book
DOI：https://doi.org/10.1007/978-3-642-22087-6_14
DOI ID：10.1007/978-3-642-22087-6_14, SCOPUS ID：84929561702 - Validation and interpretation of monitored behavior of slopes vulnerable to failure
Taro Uchimura; Ikuo Towhata; Lin Wang; Jianping Qiao
Landslide Science and Practice: Early Warning, Instrumentation and Monitoring, Volume：2, First page：589, Last page：595, 2013, [Reviewed]
Monitoring and early warning is one of the most promising ways toward reduction of disasters induced by landslides and slope instabilities. Although less costly than construction of retaining walls and other mechanical measures, early warning has several problems to be overcome. First, it is often the case that the exact location of an unstable soil mass is not defined and hence the location of monitoring sensors cannot be decided. This problem can be solved by installing many low-cost sensors within a possibly unstable slope. The second problem concerns what information of slope should be monitored. The present study has developed a low-cost MEM sensor unit that can monitor slope deformation during heavy rainfall. A wireless network collects signals from the sensors periodically and helps the local government issuing an alert signal or emergency evacuation order, depending upon the progress of tilting. It is further important that the low cost of the sensors allow individuals to purchase personally and installs them in order to protect themselves from slope disasters. The developed equipments have been deployed in several slopes in the recent times for validation of their field performances. The present text reviews the obtained records and discusses their use for practice. © Springer-Verlag Berlin Heidelberg 2013.
English, International conference proceedings
DOI：https://doi.org/10.1007/978-3-642-31445-2-77
DOI ID：10.1007/978-3-642-31445-2-77, SCOPUS ID：84898077354 - Development of low-cost early warning system of slope instability for civilian use
Taro Uchimura; Ikuo Towhata; Lin Wang; Ichiro Seko
Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, Volume：3, First page：1897, Last page：1900, 2009, [Reviewed]
A simple and low-cost early warning system is developed, and its applicability and effectiveness was tested on model slopes under artificial heavy rainfall. The system works with batteries, and transfer real time data via wireless network, and be low-cost and simple so that non-expert residents in risk area can handle it easily by themselves, even in developing countries. Traditional approaches to prevent rainfall-induced landslides, such as stabilization of unstable slopes by installation of retaining walls and ground anchors, has been useful. But, they are not very helpful in mitigation of small slope failures, which are less significant in scale but numerous in numbers, because of their cost of installation. In consequence of recent residential developments in hilly area, the risk of smaller landslides has been realized. There is extravagant number of slopes with potential of such failure, and it is not financially realistic to use traditional approaches for each of them. Low-cost and simple early warning system is needed to deal with such problems. © 2009 IOS Press.
English, International conference proceedings
DOI：https://doi.org/10.3233/978-1-60750-031-5-1897
DOI ID：10.3233/978-1-60750-031-5-1897, SCOPUS ID：84865185462 - Feasibility of Using Elastic Wave Velocity Monitoring for Early Warning of Rainfall-Induced Slope Failure
Yulong Chen, Muhammad Irfan, Taro Uchimura, Ke Zhang
Sensors, Volume：Vol. 18, No. 4, First page：pii:E997, 2008 - Shaking table tests on effect of tire chips and sand mixture in increasing liquefaction resistance and mitigating uplift of pipe
Taro Uchimura; Nguyen Anh Chi; Shantnugaratnarn Nirmalan; Takuya Sato; Mehrashk Meidani; Ikuo Towhata
SCRAP TIRE DERIVED GEOMATERIALS: OPPORTUNITIES AND CHALLENGES, First page：179, Last page：186, 2008, [Reviewed]
The authors propose to use a mixture of tire chips and sand as backfill material for buried pipes. It was found in the authors' research that a backfill with a mixture of tire chips and sand has higher liquefaction resistance compared to sand-only backfill. This implies that use of such materials for backfilling buried pipes could mitigate floating up damages.
Herein, a series of shaking table tests on scaled model of buried pipes in sand ground backfilled with tire chips-sand mixture, and a series of undrained cyclic loading tests on triaxial specimens of the mixtures are reported to discuss on advantages of use of the mixture materials.
TAYLOR & FRANCIS LTD, English, International conference proceedings
Web of Science ID：WOS:000251796400013 - Application of cement-mixed gravel reinforced by geogrid for soft ground improvement
MATSUMARU Takaki; WATANABE Kenji; ISONO Junji; TATEYAMA Masaru; UCHIMURA Taro
Geosynthetics Engineering Journal, Volume：22, First page：13, Last page：20, 2007, [Reviewed]
In recent years, cement-mixed gravel; crushed stone for mechanical stabilization with a few amount of cement, is often used for soil structure allowing a limited amount of deformation. In Japanese railway field, this material is now standardized for applying to approach block of bridge abutment of new Shinkansen line. From laboratory tests or on-site tests, it has revealed that this material shows sufficient strength and deformation characteristics equivalent to concrete. Therefore, cement-mixed gravel where geotextile is arranged for the tensile material is expected to be used as bending member, for examples, slab with ground-improvement piles as new-type countermeasure method for soft ground. As, the ratio of improvement is usually determined by the settlement of ground between piles, the ratio could be reduced by arranging this slab between soil structure and piles. The purpose of this paper is to conduct tri-axial tests, bending tests and shaking table tests experiments in order to realize this new countermeasure method.
Japan Chapter of International Geosynthetics Society, Japanese
DOI：https://doi.org/10.5030/jcigsjournal.22.13
DOI ID：10.5030/jcigsjournal.22.13, ISSN：1344-6193, J-Global ID：200902229471561591, CiNii Articles ID：130000142712 - Material properies of intermediate materials between concrete and gravelly soil
Taro Uchimura; Yuko Kuramochi; Bach Thuan Thai
SOIL STRESS-STAIN BEHAVIOR: MEASUREMENT, MODELING AND ANALYSIS, Volume：146, First page：473, Last page：+, 2007, [Reviewed]
Compaction and strength properties of cement-mixed well-graded gravel are studied. Such materials can also be considered as a kind of concrete materials which has much lower cement contents than usual. New concepts on material properties related to their mixture ratio of cement, gravel (aggregate) and water, as well as their compaction density, are proposed, unifying the concepts of geotechnical engineering and concrete engineering. For materials with higher cement contents, the compaction curve becomes flat, with lower maximum compaction density, and higher optimum water contents. The triaxial compressive strength are clearly affected by the dry density, as well as the cement contents.
SPRINGER, English, International conference proceedings
ISSN：0925-0042, Web of Science ID：WOS:000251034800029 - Residual earth pressure on a retaining wall with sand backfill subjected to forced cyclic lateral displacements
Daiki Hirakawa; Minehiro Norjiri; Hiroyuki Aizawa; Fumio Tatsuoka; Takashi Sumiyoshi; Taro Uchimura
SOIL STRESS-STAIN BEHAVIOR: MEASUREMENT, MODELING AND ANALYSIS, Volume：146, First page：865, Last page：+, 2007, [Reviewed]
A pair of about 11 m-high soil retaining walls of an U-shaped underground reinforced concrete (RC) structure in Tokyo exhibited a large residual inward (i.e., toward the active side) displacement with potential structural damage, which became 18 cm between the tops of the two walls about three years after its completion. Noticeable settlements of the backfill were observed behind the walls. A series of small-scale model tests was performed in the laboratory to understand this field behaviour. The results from in-situ investigation and model tests showed that this wall behaviour can be attributed to a gradual increase in the residual lateral earth pressure, resulting from cyclic lateral displacements of the walls caused by a small number of relatively large seasonal thermal cyclic displacement of the RC wall facing and bottom slab of the structure, not by a great number of relatively small daily displacement. Three factors for the mechanism of this wall behaviour (i.e., ratcheting, cyclic hardening and cyclic loading-induced residual deformation of the backfill) were identified and analyzed based the model test results. The settlement in the backfill observed in the model tests is consistent with the field behaviour.
SPRINGER, English, International conference proceedings
ISSN：0925-0042, Web of Science ID：WOS:000251034800065 - Behaviour of geosynthetic-reinforced soil retaining wall subjected to forced cyclic horizontal displacement at wall face
D. Hirakawa; M. Nojiri; H. Aizawa; F. Tatsuoka; T. Sumiyoshi; T. Uchimura
GEOSYNTHETICS, VOLS 1-4, Volume：3, First page：1075, Last page：+, 2006, [Reviewed]
Forced cyclic lateral displacements took place at the wall by thermal expansion/contraction of RC facing of a 11 m-high U-shape soil retaining wall due to daily and seasonal changes of the temperature, which resulted into large residual lateral displacements toward the active side of the wall due to the increment in the residual earth pressure as well as large settlement in the backfill behind the wall facing. A set of small-scale model tests was performed in the laboratory. It was found that these detrimental effects can be removed by reinforcing the backfill with polymer geogrid layers that are connected to the back face of thin RC facing.
MILLPRESS SCIENCE PUBLISHERS, English, International conference proceedings
Web of Science ID：WOS:000242400900211 - ..
渡辺健治; 松丸貴樹; 水野進正; 舘山勝; 内村太郎
Volume：21, First page：229, Last page：236, 2006, [Reviewed]
近年、土構造物の耐震性向上のためにセメント改良礫土が多く用いられるが、実際の構造体として建設されたセメント改良礫土はセメント混合ムラにより強度のばらつきが見られた。通常の場合、盛土内にはジオグリッドを敷設するため、盛土内に多少の品質ムラが存在しても全体の構造体としての影響は少ないと推測され、さらにジオグリッドは引張補強材としての効果が期待される。本研究では、室内作成および現場施工されたセメント改良礫土の曲げ試験を行い、以下の知見を得た。(1)ジオグリッド補強材に発生する張力により、セメント改良礫土の曲げ変形に対する靭性能が増加する、(2)施工によりセメント改良礫土内に弱部が存在した場合でも、ジオグリッド補強材によりその影響が緩和される。
Japan Chapter of International Geosynthetics Society, Japanese
DOI：https://doi.org/10.5030/jcigsjournal.21.229
DOI ID：10.5030/jcigsjournal.21.229, ISSN：1344-6193, J-Global ID：200902291218888751, CiNii Articles ID：130003450831 - Effects of wetting and drying on the unsaturated shear strength of a silty sand under low suction
Chaminda Pathma Kumara Gallage; Taro Uchimura
Geotechnical Special Publication, Number：147, First page：1247, Last page：1258, 2006, [Reviewed]
Shear strength properties of unsaturated soils are important in evaluating the stability of geotechnical structures such as natural slopes, embankments, retaining walls, excavations, and footings. This importance is more in countries, where intense rainfalls cause the instability of natural and man-made slopes. An unsaturated soil behaves differently at wetting and drying and this difference in behavior is referred to as hysteresis. Hysteresis is often exhibited in soil-water characteristic curves of unsaturated soils. The hysteresis in the shear strength behavior of unsaturated soil under wetting and drying has not been fully investigated. Shear strength tests on unsaturated soils have usually been conducted following the drying process. For example, in a multi-stage shear test, the soil is subjected to increasing matric suctions at subsequent stages. Very few studies have been conducted on the unsaturated shear strength parameters on wetting process by which slopes become more unstable. Re-compacted soil specimens of silt-sand were tested in a modified triaxial apparatus to examine the effects of wetting and drying on shear strength. Identical soil specimens were tested at wetting and drying under controlled air and water pressures. The study was conducted for low suction range, (i.e. 0-50 kPa). The soil at the drying had lower shear strength as compared to the soil at the wetting under the same matric suction. Furthermore, the study was extended to investigate the effects of suction and the hysteresis of SWCC on shear strength parameters such as effective friction angle and the apparent cohesion, c. Results exhibited no significant effects of suction and the hysteresis of SWCC on the effective friction angle. It was observed that the apparent cohesion at the wetting was higher than that was obtained at the drying under the same suction. The c increases as the suction increase with the decreasing rate at wetting. Copyright ASCE 2006.
English, International conference proceedings
DOI：https://doi.org/10.1061/40802(189)102
DOI ID：10.1061/40802(189)102, ISSN：0895-0563, SCOPUS ID：33845518999 - Unsaturated infiltration on artificial embankments reinforced with geosynthetics
E. F. Garcia; C. P. K. Gallage; T. Uchimura
GEOSYNTHETICS, VOLS 1-4, First page：1417, Last page：+, 2006, [Reviewed]
It is well known that geosynthetics have been used successfully in separation, reinforced and consolidation of engineered earth systems. However, the drainage behavior due to rainfall infiltration of geosynthetics in reinforced embankments has not been well addressed so far. Drainage ability of geosynthetics is important since soil strength increases and decreases when water content changes. In order to analyze the effect of water infiltration due to rainfall on soil-geosynthetic systems, reinforced and non-reinforced embankment tests were conducted. The artificial reinforced embankments were built using two layers of geosynthetics; rainfall was simulated by using spray irrigation tube. Cycles of wetting (rainfall) and drying processes were applied to the embankments. The change in pore water pressure and water content during drying and wetting processes were monitored by modified water pressure sensors attached with ceramic cup and moisture sensors, respectively. Water retention characteristic curves were measured for soil and geosynthetics. Geosynthetics worked as a capillary barrier maintaining the soil above them with high degree of saturation. Failure was observed in both cases, reinforced and no-reinforced embankments. It was found that failure in no-reinforced embankments was initiated by the growth up of pore pressure within the soil at the toe of the embankment. The failure in reinforced embankment showed a different pattern; water content and pore pressure increased immediately above the geosynthetic layers and failure started above them.
MILLPRESS SCIENCE PUBLISHERS, English, International conference proceedings
Web of Science ID：WOS:000242400900288 - STRENGTH AND DEFORMATION CHARACTERISTICS OF RECYCLED CONCRETE AGGREGATE AS A BACKFILL MATERIAL
AQIL UMAIR; TATSUOKA FUMIO; UCHIMURA TARO; LOHANI TARA NIDHI; TOMITA YUICHI; MATSUSHIMA KENICHI
SOILS AND FOUNDATIONS, Volume：45, Number：5, First page：53, Last page：72, Oct. 2005
A series of consolidated drained triaxial compression tests were performed on recycled concrete aggregates to investigate the feasibility of their use as a backfill material for geotechnical engineering structures requiring a high stability while allowing a limited amount of deformation, such as embankments and conventional type and geosynthetic-reinforced soil retaining walls supporting highway and railway. The experimental results showed the following. The compressive strength qmax when well compacted at water content in the vicinity of the optimum water content wopt is similar to that of typical well graded gravelly soil that is categorized as the highest class backfill material. When well compacted at the same energy level, the peak strength and pre-peak stiffness of recycled concrete aggregate is insensitive to changes in the moulding water content relative to wopt. When well compacted around wopt, the effect of confining pressure on qmax is similar to the one of typical well graded gravelly soil, while confined saturation does not have any detrimental effects on the qmax and pre-peak stiffness. With a decrease in the compacted dry density from the maximum dry density at fixed water content around wopt for a given compaction energy level, the qmax and pre-peak stiffness decreases at a very high rate. The viscous property of the recycled concrete aggregate is similar to the one of ordinary type backfill materials. When well compacted around wopt, residual strains by sustained and cyclic loading are not significant.
The Japanese Geotechnical Society, English
DOI：https://doi.org/10.3208/sandf.45.5_53
DOI ID：10.3208/sandf.45.5_53, ISSN：1341-7452, CiNii Articles ID：110003983965, CiNii Books ID：AN10496056 - Strength and deformation characteristics of recycled concrete aggregate in triaxial compression
Umair Aqil; Fumio Tatsuoka; Taro Uchimura
Geotechnical Special Publication, Number：130-142, First page：2231, Last page：2240, 2005
To investigate the feasibility of the use of recycled concrete aggregate as the backfill material of geotechnical engineering structures, such as embankments, geo-synthetic reinforced soil retaining walls and bridge abutments, a series of drained triaxial compression tests were performed. Both axial and lateral strains were measured locally. It was found that the compressive strength, q max, of recycled concrete aggregate highly compacted at water content in the vicinity of optimum moisture content, w opt, becomes similar to that of well-graded gravel that has been used as the backfill material of highest quality. When compacted at w opt, post-compaction saturation does not have any detrimental effect on q max of recycled concrete aggregate. The viscous aspects of the stress-strain characteristics were evaluated. Upon the restart of MLfollowing each creep stage, t he specimen exhibited very stiff and nearly elastic response for some stress range followed by marked yielding. The changes in the stress ratio upon a stepwise change in the axial strain rate were rather proportional to the instantaneous stress ratio and the logarithm of the ratio of the strain rates after and before a step change. These trends are very similar to those of ordinary type backfill materials.
English, International conference proceedings
ISSN：0895-0563, SCOPUS ID：17044393490 - ジオシンセティックス補強材の設計破断強度におけるクリープ低減係数の意味について
龍岡 文夫; 篠田 昌弘; 内村 太郎
Volume：19, First page：263, Last page：270, 2004
ジオシンセティックス補強土構造物の設計において、補強材の設計引張り破断強度は基本的な設計データの一つである。ジオシンセティックス補強土構造物の長期安定を確保するために必要な補強材設計破断強度は、通常、施工、耐久性、クリープ等の影響を考慮して「新製品の急速定ひずみ速度引張り試験による引張り強度」を低減して決定される。この内、クリープ低減係数が特に大きく、補強材の設計強度の算定に大きく影響する。それにも係わらず、その設定法は合理的ではない面があり過度に安全側となっている可能性が高い。本論文では、クリープ低減係数を無条件には用いないで、また盛土のせん断強度としてピーク及び残留せん断強度を用いる新しい補強材の設計強度算定法を提案し、簡単な算定例を示す。
Japanese
DOI：https://doi.org/10.5030/jcigsjournal.19.263
DOI ID：10.5030/jcigsjournal.19.263, ISSN：1344-6193, J-Global ID：200902216957171863, CiNii Articles ID：130003681043 - Viscous Properties of Recycled Concrete Aggregate in Triaxial Compression
Umair Aqil; Uchimura Taro; Tatsuoka Fumio; Matsushima Kenichi; Mohri Yoshiyuki
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：39, First page：611, Last page：612, 2004
The viscous aspects of the stress-strain characteristics of recycled concrete aggregate in triaxial compression were evaluated by performing strain-controlled tests on unsaturated specimens compacted at or close to the optimum moisture content. Cyclic loading histories were also applied at various stress levels to evaluate components by viscous effects and cyclic loading effects. The specimen exhibits very stiff and nearly elastic stress-strain behaviour upon the restart of monotonic loading (ML) at constant strain rate following creep and cyclic loading stages. It is shown that the change in the stress-strain relation upon a stepwise change in irreversible strain rate is not persistent but decays with increase in irreversible strain.
The Japanese Geotechnical Society, English
DOI：https://doi.org/10.11512/jiban.JGS39.0.611.0
DOI ID：10.11512/jiban.JGS39.0.611.0, CiNii Articles ID：130004622684 - Comparison of Stress-Strain Properties of Recycled Concrete Aggregate with other Geomaterials
Uchimura Taro; Aqil Umair; Tatsuoka Fumio; Matsushima Kenichi; Mohri Yoshiyuki
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：39, First page：727, Last page：728, 2004
To investigate the overall stress-strain characteristics of recycled concrete aggregate, for the use in railway and highway embankments, a series of drained triaxial compression tests were performed on un-saturated specimen. The strength and deformation characteristics of recycled concrete aggregate were compared with other types of geomaterials available for backfill. It was found that peak strength is nearly similar to well graded gravel, and tends to become the maximum when compacted at the optimum moisture content, wopt. Ten unload-reload cycles with small axial strain amplitude of about 0.001 % were applied just after creep stage to evaluate the elastic deformation characteristics.
The Japanese Geotechnical Society, English
DOI：https://doi.org/10.11512/jiban.JGS39.0.727.0
DOI ID：10.11512/jiban.JGS39.0.727.0, CiNii Articles ID：130004622748 - The effects of cement content and the degree of compaction on the strength and deformation characteristics of cement-mixed gravel.
Kuramochi Yuko; Kongsukprasert Lalana; Uchimura Taro; Tatsuoka Fumio
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：39, First page：793, Last page：794, 2004
セメント改良礫の強度は、セメント含有率、締め固め度、含水率、裏込め材の種類によって変化する。含水率を8.75%と一定とし、乾燥密度1.8、1.9、2.0、2.05g/cm3で、セメント礫重量比を2.5、4.0、6.0、8.0%として三軸圧縮試験を行った。供試体は一定含水率で7日間大気圧下で養生した。ピーク強度と初期剛性は乾燥密度の影響を受けることが分かった。また、最適含水比で強度は最大となる。高強度を得るためには、セメント含有率を上げるだけでなく、良く締め固めることが重要であることがわかった。最も高い費用対効果を計る材料配合比のデザインについて検討した。
The Japanese Geotechnical Society
DOI：https://doi.org/10.11512/jiban.JGS39.0.793.0
DOI ID：10.11512/jiban.JGS39.0.793.0, ISSN：1342-2863, J-Global ID：200902243561032132, CiNii Articles ID：130004622785 - ジオテキスタイル補強土擁壁の変形特性に対する材料粘性の影響
平川大貴; 高岡秀明; 龍岡文夫; 内村太郎
ジオシンセティックス論文集, Volume：18, First page：175, Last page：182, Dec. 2003, [Reviewed]
豊浦砂をポリエステル補強材で補強した剛な壁面を持つ小型擁壁模型を作成し、1G場での模型載荷実験を行った。帯基礎を用いて盛土天端から鉛直載荷し、基礎の荷重～沈下特性に対する盛土と補強材の材料粘性の影響と、単調載荷・クリープ載荷・繰返し載荷という異なる載荷法が「基礎の変位～壁面に作用する土圧、補強材張力・ひずみの推移パターン～壁面の水平変位特性」に与える影響を調べた。その結果、a)基礎の鉛直変位特性と壁面の水平変位特性にも載荷速度依存性があること、b)クリープ載荷と繰返し載荷において生じる「基礎と壁面の鉛直・水平残留変位～時間関係」は定性的に等しいが、繰返し載荷時の方が残留変形の増加率が大きく収束が遅いこと、c)クリープ・繰返し載荷時において補強材ひずみは時間経過と伴に減少し、補強材がクリープ破断に至る傾向を示さないこと、が確認された。
国際ジオシンセティックス学会日本支部, Japanese
DOI：https://doi.org/10.5030/jcigsjournal.18.175
DOI ID：10.5030/jcigsjournal.18.175, ISSN：1344-6193, J-Global ID：200902218952655970, CiNii Articles ID：130003680982 - Time-dependent stress-strain behaviour due to viscous properties of geogrid reinforcement
D Hirakawa; W Kongkitkul; F Tatsuoka; T Uchimura
GEOSYNTHETICS INTERNATIONAL, Volume：10, Number：6, First page：176, Last page：199, 2003, [Reviewed]
A series of conventional and unconventional tensile tests were performed on six types of geosynthetic reinforcement to evaluate their viscous properties. It is shown that the isochronous model, according to which the load (or the stress) is a unique function of instantaneous strain and elapsed time, is unable to explain the major viscous aspects of the test results. In particular the model is unable to predict the stress-strain behaviour and rupture strength observed after loading is restarted at a constant strain rate following a creep loading or stress relaxation stage. It is argued that the widely prevailing concept that creep is a degrading phenomenon requiring the design strength to be reduced with an increase in the design lifetime is not realistic under typical field conditions where the stress-strain property does not deteriorate noticeably with time. It is also argued that this concept stems from the isochronous model. A non-linear three-component model is proposed to simulate the viscous aspects of the strength and deformation characteristics of the tested geosynthetic reinforcements. It is shown that this rheology model can simulate very well the experimental results obtained by the present study.
THOMAS TELFORD PUBLISHING, English, Scientific journal
ISSN：1072-6349, Web of Science ID：WOS:000225373800001 - Residual deformations by creep and cyclic loading of reinforced-gravel backfill and their relation
D Hirakawa; Y Shibata; T Uchimura; F Tatsuoka
DEFORMATION CHARACTERISTICS OF GEOMATERIALS, First page：589, Last page：596, 2003, [Reviewed]
To predict the long-term residual deformation of reinforced soil structure by sustained load and cyclic loading such as traffic loading, a series of laboratory model tests were performed on reinforced soil structure models. Creep and cyclic vertical loading were performed during otherwise primary loading, at the maximum load (i.e., preloaded) state and at unloaded prestressed states. The strain rate was changed stepwise during otherwise monotonic loading. Noticeable loading rate effects due to the material viscous property were observed during primary loading and preloading states, which decreased substantially by largely unloading to prestress states. Residual deformation taking place during cyclic loading with relatively small stress amplitude was mostly due to the viscous property, while the effects of cyclic loading increased with the cyclic stress amplitude. The model result was simulated by a non-linear three-component model based on the viscous property formulated based on the observed viscous property.
A A BALKEMA PUBLISHERS, English, International conference proceedings
Web of Science ID：WOS:000186344600074 - セメント改良粒調砕石盛土中のジオグリッド補強材の引抜き試験
内村 太郎; 龍岡 文夫; 青木 一二三; 米澤 豊司; 北野 陽堂; 舘山 勝; 渡辺 健治; 田村 幸彦; 桝尾 孝之
Volume：18, First page：153, Last page：160, 2003
良質な盛土材である粒度調整砕石をセメント混合により改良した盛土中に敷設された補強材の引き抜き試験を行った。同じ荷重レベルでの引き抜け量は、剛性の高いグリッドの方がかなり小さく、また、土被りが約2倍異なっても、拘束圧による引き抜け量の差は小さかった。また最大で約15mm～30mmの引き抜け変位が生じたが、荷重を除荷するとそのうち1/3程度が復元した。クリープ変位量も大きかった。また、同じジオグリッドの引張試験結果を別途行い、現場の引き抜け試験結果を比較する解析を行った。これらの結果から、柔らかい高分子補強材が、ジオグリッドが比較的固いセメント改良盛土材の中で引き抜かれる場合、張力の影響範囲が載荷とともに深い部分に拡大していき、セメント改良土と補強材のすべり特性だけでなく、補強材の引張変形特性が強く反映されていることが分かった。
Japanese
DOI：https://doi.org/10.5030/jcigsjournal.18.153
DOI ID：10.5030/jcigsjournal.18.153, ISSN：1344-6193, J-Global ID：200902240790892391, CiNii Articles ID：130003680979 - 免震基礎としてのＰＬＰＳ補強盛土の性能に関わる条件
倉持 裕子; 古谷 明寿; 内村 太郎; 龍岡 文夫
Volume：18, First page：259, Last page：266, 2003
重量構造物の免震基礎としてのPLPS補強盛土は、初期固有振動数が入力振動数よりも小さい場合において、免震効果を示す。本研究では、PLPS補強盛土の模型振動台実験を種々の条件で行い、盛土の乾燥密度、プレストレスの大きさ、ラチェット装置の有無という各種条件がPLPS補強盛土の免震性能に及ぼす効果を検討した。また、プレストレスとラチェット装置が共振時の構造物としての強さに及ぼす効果を検討した。
Japanese
DOI：https://doi.org/10.5030/jcigsjournal.18.259
DOI ID：10.5030/jcigsjournal.18.259, ISSN：1344-6193, J-Global ID：200902253991176427, CiNii Articles ID：130003680992 - ＰＬ・ＰＳ補強土橋台の限界状態設計法に関する検討および試設計
鴇田 由希; 矢崎 澄雄; 舘山 勝; 篠田 昌弘; 龍岡 文夫; 内村 太郎
Volume：18, First page：339, Last page：346, 2003
プレローディッド・プレストレスト(PL・PS)補強土工法は,ジオテキスタイルによる補強盛土に対して,壁面工構築前にプレロード荷重を作用させ,供用時にプレストレス荷重を保持して高剛性の補強盛土として変動荷重(列車)や偶発荷重(地震)による変形量の抑制を目指す工法である.地震時における耐震性も優れていることが実証されており,従来形式と比べて合理的で経済的な構造となる.このことから,橋台や橋脚等の各種の許容変形が小さい重要な永久構造物をこの方法で建設できる.しかし,これまで,PL・PS補強土工法を橋台や橋脚に適用する際の設計法が,十分に整備されていなかったことから,その普及が妨げられていた.そこで,この工法を橋台に適用した場合の,限界状態設計法を取り入れた具体的な設計手法を検討した.本論文では,これまでに検討・確立したPL・PS補強土橋台の設計法の概要と,試設計断面による具体的な設計例および従来形式橋台との設計結果の比較を報告する.
Japanese
DOI：https://doi.org/10.5030/jcigsjournal.18.339
DOI ID：10.5030/jcigsjournal.18.339, ISSN：1344-6193, J-Global ID：200902285899843831, CiNii Articles ID：130003680987 - Simulation of cyclic loading tests on geosynthetic reinforcement
Hirakawa D.; Tatsuoka F.; Uchimura T.; Kongkitkul W.
Geosynthetics Engineering Journal, Volume：18, First page：183, Last page：190, 2003
In the design procedure of geosynthetic reinforced-soil structures, the residual deformation during the service period of the structure is one of the key issues. To investigate the development of residual strain of polymer reinforcements, a series of load-controlled tensile tests was performed generating the following loading histories: a) continuous monotonic loading (ML) at a constant load rate; b) creep (or sustained) loading; and c) cyclic loading with controlled amplitudes and frequencies. Though it has been usually considered that residual straining during cyclic loading is due to the effects of time-independent cyclic loading history (i. e., as a function of the number of loading cycles; amplitude; and so on), it was found from this study that cyclic residual straining is due essentially to the loading rate effects caused by material viscous property. A non-linear three-component model originally developed for simulating the rate-dependent deformation of geomaterials (i. e., soils; and rocks) was modified to simulate the relationship between tensile load and strain for ML; creep; cyclic loading; and general loading histories obtained from the present study.
Japan Chapter of International Geosynthetics Society, English
DOI：https://doi.org/10.5030/jcigsjournal.18.183
DOI ID：10.5030/jcigsjournal.18.183, ISSN：1344-6193, CiNii Articles ID：130003680983 - ジオテキスタイルのクリープ変形と引張り強度に対するクリープ補正係数についての考察
龍岡 文夫; 平川 大貴; 内村 太郎; KONGKITKUL Warat
Volume：18, First page：167, Last page：174, 2003
盛土の引張り補強用の石油高分子ジオテキスタイル補強材は、金属製補強材と比較すると剛性が低くクリープ変形しやすい。このことから、長期材令に対する設計引張り強度を、ひずみ速度1%/分程度の引張り試験で得られた引張り強度を1.0よりもかなり大きなクリープ破断に対する安全率で除して求めている。この方法は、以下の理由によって不合理である。従来の設計法は「クリープは劣化現象であり引張り強度は時間経過とともに減少する」という誤解を与えるが、クリープ変形は劣化現象ではなく材料粘性による応答である。引張り破断強度は破断時のひずみ速度に支配され、クリープ破断しない限りクリープ変形履歴に影響されない。地震時に生じる補強材の残留変形も荷重増加と粘性によるものであり、特にクリープ破断に対する安全率を考慮する必要がない。通常のジオテキスタイル補強盛土では、常時にジオテキスタイル補強材は引張り力が時間的に低減していて、クリープ破壊の可能性は非常に低いと考えられる。時間的な材料劣化が無い場合に対して、クリープ破断に対する安全率を用いず想定した破壊時のひずみ速度で引張り破断強度を定義する方法を提案する。
Japanese
DOI：https://doi.org/10.5030/jcigsjournal.18.167
DOI ID：10.5030/jcigsjournal.18.167, ISSN：1344-6193, J-Global ID：200902286493844027, CiNii Articles ID：130003680981 - Deformation characteristics of geogrid reinforced-soil retaining wall during sustained and cyclic loadings
Takaoka Hideaki; Hirakawa Daiki; Uchimura Taro; Tatsuoka Fumio
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：38, First page：1771, Last page：1772, 2003
ジオグリッドで補強された豊浦砂盛土の擁壁模型に鉛直載荷試験を行い、各種載荷条件下での帯基礎と擁壁の変形特性、擁壁にかかる土圧と補強材張力、地盤中の補強材局所張力分布を測定して、特に豊浦砂とジオグリッドの粘性による残留変形特性を調べた。クリープ載荷時には帯基礎の残留沈下量の増加率が時間とともに減少し一定値に収束するが、繰返し載荷時には沈下が進行的であった。繰り返し載荷開始直後には擁壁上部の水平変位が受動方向に生じる現象が見られた。このような異なる挙動に関連して、帯基礎底面の応力分布は繰返し載荷では中心部に応力集中することや、擁壁にかかる土圧・補強材張力についても検討を行った。
The Japanese Geotechnical Society
DOI：https://doi.org/10.11512/jiban.JGS38.0.1771.0
DOI ID：10.11512/jiban.JGS38.0.1771.0, ISSN：1342-2863, J-Global ID：200902299118747566, CiNii Articles ID：130004620910 - Effects of several test conditions on the behavior of PLPS geotextile-reinforced soil structure as a base isolation system
Kuramochi Yuko; Furuya Akitoshi; Uchimura Tarou; Tatsuoka Fumio
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：38, First page：715, Last page：716, 2003
PLPS補強盛土は、初期固有振動数が入力振動数よりも小さい場合において、免震効果を示すことが確認されている。本論文では、重量構造物の免震基礎を想定したPLPS補強盛土の模型振動台実験を行い、裏込め材の乾燥密度、プレストレス、ラチェット装置の有無という条件を変えることによって、これらの各種条件がPLPS補強盛土の免震性能に及ぼす効果について検討した。その結果、PLPS補強盛土の免震性能のみに着目すると、乾燥密度は高い方が良く、プレストレスとラチェット装置の設置はほとんど効果が無いということが示された。
The Japanese Geotechnical Society
DOI：https://doi.org/10.11512/jiban.JGS38.0.715.0
DOI ID：10.11512/jiban.JGS38.0.715.0, ISSN：1342-2863, J-Global ID：200902203842874157, CiNii Articles ID：130004621552 - Basic properties of crashed concrete as a embankment material
Tokiwa Yuya; Uchimura Tarou; Tatuoka Fumio
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：38, First page：679, Last page：680, 2003
盛土材として粒度調整砕石の代わりに破砕コンクリート廃材を使用できれば、かなりのコストパフォーマンスを得ることが出来る。しかし、コンクリート廃材を高級盛土材として使用した例はほとんど無く、研究も少ない。本研究では、各実験に使用したコンクリート廃材の基礎的な物理特性と三軸試験による変形強度特性を調べた。 結果として、「最適含水比からのずれが、締め固め乾燥密度に及ぼす影響は少ない。最適含水比か、やや乾燥側で締め固めれば高い強度と剛性が得られる。載荷初期の剛性は低く、載荷が進むと軸応力の増加に伴い接線剛性が増加する。拘束圧の増加に伴い、原点に対する内部摩擦角は急速に減少する。」などの傾向が得られた。
The Japanese Geotechnical Society
DOI：https://doi.org/10.11512/jiban.JGS38.0.679.0
DOI ID：10.11512/jiban.JGS38.0.679.0, ISSN：1342-2863, J-Global ID：200902243994811870, CiNii Articles ID：130004621531 - Behavior at resonance of PLPS geotextile-reinforced soil structure as a base isolation system
Furuya Akitoshi; Kuramochi Yuko; Uchimura Tarou; Tatsuoka Fumio
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：38, First page：717, Last page：718, 2003
重量構造物の免振基礎を想定したPLPS補強盛土の模型振動台実験を行った結果、その免震性能のみを考慮するとプレストレスとラチェット装置は効果がなく、いわば柔らかく支持することが望ましいということがわかった。一方、実際には海洋型大地震など長周期地震動が発生し、盛土が共振するする恐れがある。本論文においては、上記の模型振動台実験においてPLPS補強盛土を共振させ、その時の盛土の物性について考察することにより、PLPS補強盛土の構造物としての強さを検討した。その結果、プレストレスを載荷し、ラチェット装置を設置することによって盛土の滑動を回避することができ、プレストレスとラチェット装置の重要性が確認された。
The Japanese Geotechnical Society
DOI：https://doi.org/10.11512/jiban.JGS38.0.717.0
DOI ID：10.11512/jiban.JGS38.0.717.0, ISSN：1342-2863, J-Global ID：200902248406310845, CiNii Articles ID：130004621553 - A new simple method to substantially increase the seismic stability of reinforced soil structures
M Shinoda; T Uchimura; F Tatsuoka; M Tateyama; T Natsuki
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING, Volume：22, Number：9-12, First page：1115, Last page：1123, Oct. 2002, [Reviewed]
A preloading and prestressing (PLPS) method has been-proposed to substantially decrease the transient and residual vertical compression of geosynthetic-reinforced soil (GRS) structures subjected to long-term traffic load. It is shown that by using a newly developed device (called the ratchet system) in addition to the PLPS procedure, the seismic stability of PLPS GRS structures becomes very high. The ratchet system can not only maintain high prestress when the backfill tends to contract but also prevent the expansion of the backfill, both effectively restraining the shear and bending deformation of the structure subjected to seismic load. (C) 2002 Elsevier Science Ltd. All rights reserved.
ELSEVIER SCI LTD, English, Scientific journal
DOI：https://doi.org/10.1016/S0267-7261(02)00137-9
DOI ID：10.1016/S0267-7261(02)00137-9, ISSN：0267-7261, Web of Science ID：WOS:000180004500044 - 免震基礎としてのＰＬＰＳジオテキスタイル補強盛土の振動台実験
古谷 明寿; 半井 健一郎; 内村 太郎; 龍岡 文夫
Volume：17, First page：41, Last page：48, 2002
タイロッドを用いてプレロード・プレストレスされたPLPSジオテキスタイル補強盛土は、常時は鉛直荷重に対して高い剛性と安定性を示し、水平繰返し載荷に対しては高い減衰率・柔軟性・靭性を示して過大なせん断変形に対しては硬化する能力がある。本研究ではこの性質に注目して、橋梁基礎構造物・重量電力施設等の重量構造物を想定した模型振動台実験を行うことにより、PLPS補強盛土の重量構造物の免震基礎として利用する可能性を検討した。また加振中の盛土の物性についての詳細な検討を行い、免震構造物としてのシステムの動特性が及ぼす影響についても考察した。
Japanese
DOI：https://doi.org/10.5030/jcigsjournal.17.41
DOI ID：10.5030/jcigsjournal.17.41, ISSN：1344-6193, J-Global ID：200902122157598937, CiNii Articles ID：130003680925 - Effects of Viscous Property on Residual Deformation of Geogrid Subjected to Cyclic Loading
Kongkitkul W.; Hirakawa D.; Tatsuoka F.; Uchimura T.
Geosynthetics Engineering Journal, Volume：17, First page：159, Last page：166, 2002
Residual deformation of two types of geogrid subjected to cyclic loading, simulating traffic loading, was evaluated by performing a series of load-controlled cyclic loading tensile tests. Cyclic tensile loads were applied at two or three different load levels, at five different loading frequencies with two different load amplitudes. Creep loading tests were performed at the same loading levels as the cyclic loading tests. The two potential influencing factors for the development of residual deformation of geogrid during cyclic loading are; 1) loading rate effects due to material viscous properties; and 2) time-independent cyclic loading effects. Among the two, the loading rate effects are much more dominant on the residual deformation during cyclic loading within the limit of the test conditions in the present study, showing that it is necessary to introduce the loading rate effects in a constitutive model to predict the residual deformation of geogrid subjected to cyclic loading.
Japan Chapter of International Geosynthetics Society, English
DOI：https://doi.org/10.5030/jcigsjournal.17.159
DOI ID：10.5030/jcigsjournal.17.159, ISSN：1344-6193, CiNii Articles ID：130003680931 - 補強土構造物の定荷重および繰返し荷重による変形特性
内村 太郎; 柴田 芳雄; 平川 大貴; 伊藤 寛倫; 龍岡 文夫; KO Dong-Hee
Volume：17, First page：221, Last page：226, 2002
ジオテキスタイル補強土構造物の常時の性能として、上部構造物の荷重と自重による定荷重、および交通荷重などによる繰返し荷重に対する変形性が重要である。このような変形を予測するためには、盛土材の定荷重、繰返し荷重に対する変形特性を知る必要がある。これらの性質について、補強土橋脚の小型模型への載荷試験、盛土材の三軸圧縮試験、および実現場の補強土構造物の長期計測・載荷試験の結果から、考察を行う。
Japanese
DOI：https://doi.org/10.5030/jcigsjournal.17.221
DOI ID：10.5030/jcigsjournal.17.221, ISSN：1344-6193, J-Global ID：200902114629959260, CiNii Articles ID：130003680941 - The Shear Zone Pattern of Reinforced Soil in Direct Shear Test
Matsushima K.; Wu P.; Uchimura T.; Tatsuoka F.; Mohri Y.
Proceedings of the Japan National Conference on Geotechnical Engineering, Volume：37, First page：765, Last page：766, 2002
The Japanese Geotechnical Society
DOI：https://doi.org/10.11512/jiban.JGS37.0.765.0
DOI ID：10.11512/jiban.JGS37.0.765.0, ISSN：1342-2863, J-Global ID：200902190223175932, CiNii Articles ID：130004620350 - ジオグリッドの時間依存変形強度特性とその構成モデルの検討
平川大貴; 龍岡文夫; 内村太郎
ジオシンセティックス論文集, Volume：16, First page：19, Last page：26, Dec. 2001, [Reviewed]
The isochronous theory is popular in modelling the time-dependant strength and deformation characteristics of polymer geotextile for the design of reinforced soil structures. According to this theory, the tensile load of reinforcement is a function of instantaneous strain and elapsed time. Thus, the design strength would reduce monotonously with time elapsing. It is shown that the isochronous concept is not able to explain the tensile behavior of reinforcement observed in the present study, in particular the behavior after loading is restarted at a constant strain rate after a creep and relaxation. Experimentally observed time dependency of tensile characteristics of geogrid is reported, and an analytical simulation of the tension test results on geogrid by one type of three-component model was performed. The results of an experimental and analytical investigation showed that the proposed constitutive model is relevant to simulate the time-dependent deformation and strength characteristics of the tested geogrid.
国際ジオシンセティックス学会日本支部, Japanese
DOI：https://doi.org/10.5030/jcigsjournal.16.19
DOI ID：10.5030/jcigsjournal.16.19, ISSN：1344-6193, J-Global ID：200902132518006628, CiNii Articles ID：130003450725 - Time-dependent deformation characteristics of stiff geomaterials in engineering practice
F Tatsuoka; T Uchimura; K Hayano; J Koseki; H Di Benedetto; MSA Siddiquee
PRE-FAILURE DEFORMATION CHARACTERISTICS OF GEOMATERIALS, VOL 2, First page：1161, Last page：1250, 2001, [Reviewed]
The prediction of long-term residual deformation of ground and displacement of completed structures under sustained load is discussed, Based on several case histories of field full-scale behaviour of backfill, ground and proto-type structures, two important factors; a) effects of recent strain history on the creep rate; and b) time-dependent stress-strain behaviour under unloaded conditions, including the creep recovery phenomenon, are focused. Results from laboratory stress-strain-time tests and model loading tests that show the above are presented, Several basic theoretical issues related to constitutive modelling of the stress-strain-time property of geomaterials are discussed. The isotach property is discussed and a new model is proposed.
A A BALKEMA PUBLISHERS, English, International conference proceedings
Web of Science ID：WOS:000173158100008 - Seismic stability of preloaded and prestressed reinforced soil structure against strong shaking
M Shinoda; T Uchimura; F Tatsuoka; M Tateyama; T Natsuki
LANDMARKS IN EARTH REINFORCEMENT, VOL 1, First page：459, Last page：464, 2001, [Reviewed]
To substantially increase the vertical stiffness and reduce the vertical residual compression of geotextile-reinforced soil (GRS) structures subjected to long-term traffic load, the preloading and prestressing (PLPS) method has been proposed. The seismic stability of PLPS GRS structures was investigated by performing shaking table model tests using sinusoidal waves with horizontal acceleration of 700 gals. The use of a newly developed device, called the ratchet system, is very effective in increasing the seismic stability of the structures by maintaining high prestress when the backfill tends to contract and preventing the expansion of the backfill. These functions effectively prevent the occurrence of resonant state while restraining the bending deformation of the structure, which are essential for the high seismic stability of the structure.
A A BALKEMA PUBLISHERS, English, International conference proceedings
Web of Science ID：WOS:000173445800083 - Shaking Table Tests of Preloaded and Prestressed Reinforced Soil Abutment with a Ratchet System
Kenichiro NAKARAI; Masahiro SHINODA; Kenji WATANABE; Masaru TATEYAMA; Taro UCHIMURA; Fumio TATSUOKA
Geosynthetics Engineering Journal, Volume：16, First page：45, Last page：52, 2001
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.16.45
DOI ID：10.5030/jcigsjournal.16.45, ISSN：1344-6193, eISSN：1883-146X, J-Global ID：200902167771268777 - Effect of creep and cyclic loading on vertical compression property of preloaded and prestressed reinforced soil model
SHIBATA Yoshio; HIRAKAWA Daiki; SHINODA Masahiro; UCHIMURA Taro; TATSUOKA Fumio
Geosynthetics Engineering Journal, Volume：16, First page：155, Last page：158, 2001
To evaluate the effects of preloading and prestressing on deformation characteristics by cyclic loading for a long term performance of reinforced soil structures, a series of cyclic and creep tests were performed on small models. No distinct difference was found in the increasing rate with time of residual strain between a cyclic loading test and a constant pressure creep test at a preloading state. The amount of residual strain by cyclic loading at an unloaded state (i. e., prestressed state) decreased by applying in advance long-term constant pressure or cyclic loading at the preloaded condition. Applying cyclic loading at the preloading state was slightly more effective. When swelling was allowed to take place at a prestress state. the deformation during the subsequent cyclic loading test became larger.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.16.155
DOI ID：10.5030/jcigsjournal.16.155, ISSN：1344-6193, J-Global ID：200902128290657553, CiNii Articles ID：130003450718 - Natural Frequency of Full-scale Preloaded and Prestressed Geosynthetic-Reinforced Soil Pier
Nakarai K.; Shinoda M.; Yamamoto S.; Kojima K.; Tateyama M.; Uchimura T.; Tatsuoka F.
Geosynthetics Engineering Journal, Volume：15, First page：302, Last page：311, 2000
The behavior of a pier during earthquake is controlled by the relationship between the natural frequency of structure and the predominant frequency of input motion. The natural frequency of a full-scale preloaded and prestressed geosynthetic-reinforced soil pier of Umaide Bridge was evaluated by measuring the particle velocity at several points of the structure by applying an impact to the structure. The results showed that the natural frequencies in the normal and to in parallel to the girder axis were found to be about 7Hz and 9Hz, respectively. The measured natural frequencies of the pier were compared with those from small-scale model tests in the laboratory and their theoretical solution. The natural frequencies of the full-scale structure, were about a half of those in the models. It is inferred that the difference between the behaviors of the full-scale structure and the scaled model is due to the different base conditions, based on the deformable ground in the field and on a rigid plate in the laboratory.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.15.302
DOI ID：10.5030/jcigsjournal.15.302, ISSN：1344-6193, J-Global ID：200902158456673192, CiNii Articles ID：130003450695 - Dynamic characteristics of preloaded and prestressed reinforced soil against level II shaking
Shinoda M.; Ishimura T.; Nakarai K.; Yamamoto S.; Natsuki T.; Kato T.; Kitano Y.; Kato N.; Uchimura T.; Tatsuoka F.
Geosynthetics Engineering Journal, Volume：15, First page：274, Last page：283, 2000
The preloaded and prestressed (PLPS) reinforced soil method has been proposed to substantially increase the vertical stiffness of reinforced soil structures against level II shaking. To evaluate the seismic stability of PLPS reinforced soil structures, we performed a series of shaking table tests by using sinusoidal waves having an acceleration level of 700 gals to take similarity rule into account. A fine uniform sand or a well-graded gravel were used for the backfill. The gravel backfill exhibited a much higher dynamic stability under otherwise the same conditions. The maintenance of sufficiently high prestress was found to be the key for a high dynamic stability of the structure. The use of a ratchet mechanism was found to be very effective for this purpose.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.15.274
DOI ID：10.5030/jcigsjournal.15.274, ISSN：1344-6193, CiNii Articles ID：130003450691 - Shaking Table Tests on Preloaded and Prestressed Reinforced Soil Structures using a Prestress-Maintaining System with a Ratchet
Yamamoto S.; Shinoda M.; Nakarai K.; Natsuki T.; Kato T.; Kitano Y.; Kato N.; Uchimura T.; Tatsuoka F.
Geosynthetics Engineering Journal, Volume：15, First page：284, Last page：293, 2000
A decrease in the prestress value by seismic load is one of the most serious potential problems on PLPS reinforced soil structures. To alleviate this problem, the best way is to set a ratchet system which keeps the prestress during earthquake and traffic cyclic loading and restrains the expansion of embankment. On the other hand, it is also important to investigate the behavior of structures during resonance. We investigated the effects of a ratchet system on the seismic behavior of the structures by shaking table tests. In particular, the behavior of structures around the resonance state was investigated.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.15.284
DOI ID：10.5030/jcigsjournal.15.284, ISSN：1344-6193, J-Global ID：200902148736564580, CiNii Articles ID：130003450693 - Effects of Using Tie Rods on the Seismic Stability of Preloaded and Prestressed Reinforced Soil Structures
Tatsuoka F.; Shinoda M.; Kikuchi T.; Sugimura Y.; Uchimura T.
Geosynthetics Engineering Journal, Volume：14, First page：120, Last page：129, 1999
Static cyclic horizontal loading tests were performed on small-scale models of preloaded and prestressed (PL/PS) reinforced soil bridge pier to investigate effects of using tie rods on the seismic stability of the structure. The tie rod tension increases when the height of backfill increases, and decreases when the height of backfill decreases. As a result, when a PL/PS structure exhibits bending deformation by seismic loads, the tie rod tension increases to effectively restrain the deformation of the structure. However, if the initial level of prestress is too low, the confining pressure on soil becomes very small at the elongation side of the bending motion, resulting into large soil deformation, and it causes large residual settlements by shaking and a large reduction in the tie rod tension. Therefore, for the effective use of tie rods to increase the seismic stability of structure, it is important to keep a high prestress level.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.14.120
DOI ID：10.5030/jcigsjournal.14.120, ISSN：1344-6193, J-Global ID：200902132095188783, CiNii Articles ID：130003680870 - Shaking Table Tests to investigate the seismic stability of preloaded and prestressed reinforced soil
Shinoda M.; Kikuchi T.; Sugimura H.; Ushimura T.; Tatsuoka F.
Geosynthetics Engineering Journal, Volume：14, First page：130, Last page：140, 1999
Preloaded and prestressed reinforced soil structures can have very high stiffness exhibiting very small residual settlements during service. To study the seismic stability of the structure, we performed shaking table tests with various values of preloading and prestressing. The equation to give the resonance frequency of PL/PS reinforced soil bridge pier is proposed. It is shown that preloading has effects in making the axial displacement in the side zone of backfill during cyclic loading more elastic and thereby in decreasing the residual displacement, and the prestressing has effects in increasing the resonance frequency and when the structure does not resonate, thereby in restraining the residual settlement of backfill during shaking, showing the importance of introducing sufficiently large prestress. It is shown that when the structure does not resonate, the residual settlement of PL/PS reinforced soil structure could be negligible and even when the structure resonates, PL/PS reinforced soil structures would not collapse with sufficiently high prestress being maintained.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.14.130
DOI ID：10.5030/jcigsjournal.14.130, ISSN：1344-6193, J-Global ID：200902142677935775, CiNii Articles ID：130003680871 - Reinforcing Mechanism Constant Pressure Direct Shear Tests on Sand
Wu Po-Kai; Qiu Jin-Ying; Uchimura T.; Tatsuoka F.
Geosynthetics Engineering Journal, Volume：14, First page：185, Last page：194, 1999
Reinforced sand shows larger dilatancy associated with a larger volume of shear zone in direct shear tests, compared to unreinforced sand. It is likely that multiple shear bands develop forming a thicken shear zone, resulting in larger dilatancy. Air-dried sand specimens reinforced with phosphor bronze strips installed perpendicularly to the shear direction were tested by using a medium scale direct shear test apparatus. The test results were analyzed with a new mechanical model using estimated thicknesses of shear zone as one on the major input parameters.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.14.185
DOI ID：10.5030/jcigsjournal.14.185, ISSN：1344-6193, J-Global ID：200902188654260240, CiNii Articles ID：130003680877 - Behavior of the first prototype and full-scale models of PLPS geosynthetic-reinforced soil structure
Taro Uchimura; Fumio Tatsuoka; Masaru Tateyama; Tetsushi Koga
Geotechnical Special Publication, Number：76, First page：34, Last page：48, 1998
It is shown that even very densely compacted reinforced backfill could exhibit large creep deformation by static loading and residual deformation by cyclic loading. A new construction method by means of vertical preloading and prestressing is described, which makes reinforced soil structures very stiff, exhibiting very small creep, transient, and residual deformations. The performance of a railway bridge pier, constructed in 1996 as the first preloaded and prestressed geosynthetic-reinforced soil structure, is presented, compared with the behavior of three full-scale models during loading tests.
English, Scientific journal
ISSN：0895-0563, SCOPUS ID：0032308693 - Effects of compaction, pre-loading and pre-stressing on deformation characteristics of reinforced high-water content and saturated clay
Roh Hansung; Tatsuoka Fumio; Uchimura Taro; Yoshimura Kei
Geosynthetics Engineering Journal, Volume：13, First page：95, Last page：104, 1998
The reinforced soil has been widely used for constructing retaining walls and embankments with steep slope, stabilizing embankment on soft ground, and so on. However, the benefits of soil reinforcing are often restricted by a lack of good quality backfill material. In many cases, use of on-site high-water content and nearly saturated cohesive soil could save substantial cost. Plane strain compression tests have been carried out to study the effects of preloading and prestressing on the stress-strain behavior of geosynthetic-reinforced saturated clay, Kanto loam. The initial stiffness and ultimate strength of a reinforced clay during undrained shearing tests increase substantially by preloading and prestressing. With small prestress after large unloading from preloaded condition resulted into swelling of the soil, leading to a large reduction in the initial stiffness in undrained shearing. The results of compaction model tests have shown that reinforcement is essential for efficient compaction.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.13.95
DOI ID：10.5030/jcigsjournal.13.95, ISSN：1344-6193, J-Global ID：200902132703652234, CiNii Articles ID：130003680866 - Deformation characteristics on models of preloaded and prestressed reinforced soil structure during axial cyclic loading
Shinoda Masahiro; Uchimura Taro; Maruyama Naoki; Tatsuoka Fumio
Geosynthetics Engineering Journal, Volume：13, First page：85, Last page：94, 1998
A new construction technology has been proposed to increase substantially the vertical stiffness of GRS soil structures to make the deformation of the backfill in service essentially elastic, sufficiently large vertical preloading is applied to the backfill and to keep the stiffness of the backfill in service sufficiently high, preloading is not unloaded to zero, but sufficiently high vertical prestress is maintained within the backfill. In this study, a series of laboratory model tests were performed to quantitatively and separately evaluate effects of preloading and prestressing, and those of the use of tie rods for prestressing. It should be finally underlined that necessary and sufficiently large preload and prestress can be applied to the reinforced backfill. On the other hand, such levels of preload and prestress cannot be applied to usual unreinforced backfill without excessive deformation or even failure, therefore very high stiff backfill can be realized only when applying the preloading and prestressing method to appropriately designed reinforced soil structures.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.13.85
DOI ID：10.5030/jcigsjournal.13.85, ISSN：1344-6193, J-Global ID：200902189938729538, CiNii Articles ID：130003680865 - Constant-Pressure and Constant-Volume Direct Shear Characteristics of Reinforced Sand
Qiu Jin-Ying; Tatsuoka F.; Uchimura T.
Geosynthetics Engineering Journal, Volume：13, First page：296, Last page：305, 1998
In order to investigate the deformation and strength characteristics of reinforced sand, a series of direct shear tests were performed. Phosphor bronze strips or sheets were used as reinforcement. Constant volume tests, as well as constant pressure tests, were conducted with different forms of reinforcement stiffness, surface area and surface friction. Test results show that the reinforcing efficiency is higher for reinforcement with larger surface area and rough surface texture. The dilatancy and shear displacement at the residual state also depends on the reinforcement property and geometry. The shear zone become wider in tests on reinforced sand than in tests on sand alone. As high dilatancy of reinforced sand, the peak shear stress and peak vertical stress increase a great deal than those of unreinforced sand.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.13.296
DOI ID：10.5030/jcigsjournal.13.296, ISSN：1344-6193, CiNii Articles ID：130003680851 - A study of horizontal deformation feature on Preloaded/Prestressed reinforced embankment
Sugimura Yoshihisa; Shinoda Masahiro; Kikuchi Tatsuya; Tatsuoka Fumio; Uchimura Taro
Geosynthetics Engineering Journal, Volume：13, First page：270, Last page：277, 1998
Since preloaded/prestressed (PL·PS) reinforced soil method had been developed, various researches have been done. These results indicate that preloaded/prestressed reinforced embankments have high stiffness and superior feature on residual settlement against vertical load. But there is no researches on earthquake resistance, which is one of the most important performances, and even no research on horizontal deformation characteristics, which is a basis of earthquake resistance characteristics. Preloaded/prestressed reinforced soil structure must always keep high prestress. If cyclic load is applied to preloaded/prestressed reinforced soil structure in a lateral direction, there is a possibility that all or part of prestress is lost. If all or part of prestress is lost, the structure can not have high stiffness.As one of studies on earthquake resistance of preloaded/prestressed reinforced soil structures, shaking table tests on retaining wall models are conducted to study the feature of lateral deformation. It was found that preloaded/prestressed reinforced soil structures have superior deformation feature against lateral cyclic load.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.13.270
DOI ID：10.5030/jcigsjournal.13.270, ISSN：1344-6193, J-Global ID：200902170365440284, CiNii Articles ID：130003680848 - Creep deformation and stress relaxation in preloaded/prestressed geosynthetic-reinforced soil retaining walls
Fumio Tatsuoka; Taro Uchimura; Masaru Tateyama; Katsumi Muramoto
Geotechnical Special Publication, Number：61, First page：258, Last page：272, 1996
A new construction method which aims at increasing substantially the stiffness of a geosynthetic-reinforced soil retaining wall by vertical preloading and prestressing is described. The behaviour of field full-scale models with gravel and clay backfill during preloading and under prestress for more than a half year are presented. Rheological properties of the backfill soil, which plays an essential role for this method, were determined from triaxial tests.
English, Scientific journal
ISSN：0895-0563, SCOPUS ID：0030383414
- Slope Failure Prediction Method Using Approximate Linear Prediction Method Based on Velocity Inverse Method
福原誠; 福原誠; 内村太郎; TAO S.
地盤工学研究発表会(Web), Volume：59th, 2024
J-Global ID：202502256120332116 - 斜面防災の最新動向 斜面の微小変位の監視に基づく崩壊予測
内村太郎; WANG Lin
Volume：51, Number：8, 2023
ISSN：0285-5356, J-Global ID：202302289853836708 - Compaction tests on cement-mixed sand with light weightparticles (EPS)
市村和輝; 内村太郎
地盤工学研究発表会(Web), Volume：57th, 2022
J-Global ID：202302243376427718 - Compaction characteristic of cement-mixed soil mixed with lightweight granules (EPS)
市村和輝; 内村太郎
地盤工学研究発表会(Web), Volume：57th, 2022
J-Global ID：202302271667307963 - Evaluation of water retention for recycled road base aggregates blended with autoclave aerated concrete grains
伊藤良平; 加藤晃; 松野晃大; 内村太郎; 川本健
地盤工学研究発表会(Web), Volume：55th, 2020
J-Global ID：202102246254464829 - Inverse velocity method applied on direct shear tests simulating slope failure due to heavy rainfall
市村祐哉; 内村太郎; 福原誠
地盤工学研究発表会(Web), Volume：55th, 2020
J-Global ID：202102263256120776 - Influence of Capillary Barrier of Intercalated Gravel Layer on Deformation during rainfall
福原誠; 内村太郎; TAO Shangning; TANG Junfeng
地盤工学研究発表会(Web), Volume：55th, 2020
J-Global ID：202102275607088009 - Changes in total stress on liquefied sand induced by lateral flow
磯岡一; REDINOVIRIA Betzy Nella; 内村太郎
地盤工学研究発表会(Web), Volume：55th, 2020
J-Global ID：202102275662873922 - Measurement of water contents in an unsaturated ground model using colored water and image analysis
戸田樹; TANG Junfeng; 内村太郎
地盤工学研究発表会(Web), Volume：55th, 2020
J-Global ID：202102278396341114 - 熊本地震により損傷を受けた自然斜面の降雨に伴う変動のメカニズム
笹原克夫; 内村太郎; 平岡伸隆; 土佐信一; 遊佐直樹; 板山達至; 王林; 西條敦志
Volume：2019, 2019
ISSN：2433-0477, J-Global ID：201902242763045899 - 熊本地震により損傷を受けた自然斜面における降雨時の変形挙動の計測(2)
土佐信一; 遊佐直樹; 笹原克夫; 内村太郎; 平岡伸隆; 板山達至; 王林; 西條敦志
Volume：2019, 2019
ISSN：2433-0477, J-Global ID：201902262684673017 - FEMによるLME割れ評価法の確立
内村太郎; 野木優香; 生島一樹; 柴原正和
Number：105, 2019
J-Global ID：202002233042133807 - 阿蘇外輪山上部のテフラ堆積斜面の繰り返し降雨による変形メカニズム
笹原克夫; 内村太郎; 平岡伸隆; 土佐信一; 遊佐直樹; 板山達至; WANG Lin; 西條敦志
Volume：58th, 2019
J-Global ID：201902291812536506 - Evaluation of water retention and gas transport properties for recycled road base materials blended with autoclave aerated concrete grains
伊藤良平; 加藤晃; 松野晃大; 内村太郎; 川本健
地盤工学研究発表会(Web), Volume：54th, 2019
J-Global ID：202002228273675695 - Changes in elastic wave velocity in multilayered shear models test of slope surface
柴田智也; TAO S.N.; 高橋良輔; 福原誠; 内村太郎
地盤工学研究発表会(Web), Volume：54th, 2019
J-Global ID：202002232830855260 - 保水性の異なる多層からなる斜面表層地盤の雨水浸透
田中敦樹; 唐俊峰; 内村太郎
Volume：54th, 2019
J-Global ID：202002234671149449 - Study on the shear deformation in pre-failure stage of slope failure using result of multi-layer shear models test
福原誠; 内村太郎; 高橋良輔; TAO S.; 柴田智也
地盤工学研究発表会(Web), Volume：54th, 2019
J-Global ID：202002238486481730 - 斜面表層内のひずみ速度分布が崩壊時刻の予測に与える影響
高橋良輔; 陶尚寧; 柴田智也; 内村太郎; 福原誠
Volume：54th, 2019
J-Global ID：202002288716868136 - 熊本地震により損傷を受けた自然斜面における亀裂の拡大-阿蘇市的石地区の事例-
笹原克夫; 内村太郎; 平岡伸隆; 土佐信一; 大類光平; 板山達至; 王林; 西條敦志
Volume：2018, 2018
ISSN：2433-0477, J-Global ID：201802234909606865 - 熊本地震により損傷を受けた自然斜面における降雨時の変形挙動の計測
土佐信一; 大類光平; 笹原克夫; 内村太郎; 平岡伸隆; 板山達至; 王林; 西條敦志
Volume：2018, 2018
ISSN：2433-0477, J-Global ID：201802237191083126 - 変状が見られる斜面への小型孔内傾斜センサーの設置及び観測事例
福原誠; WANG L.; 西江俊作; 山口弘志; 藤谷久; 内村太郎
Volume：53rd, 2018
J-Global ID：201802231081165804 - 2016年熊本地震の被災斜面における傾斜と土壌水分の長期多点観測事例
WANG L.; 西江俊作; 内村太郎; 笹原克夫
Volume：53rd, 2018
J-Global ID：201802240174915175 - 多重せん断土槽を用いた斜面表層崩壊の予兆現象に関する研究
神保慧; 福原誠; 内村太郎
Volume：53rd, 2018
J-Global ID：201802243424084140 - 斜面のすべり面の形状と表層で観測される傾斜・変位の関係
今野朗; XIE Jiren; 内村太郎
Volume：53rd, 2018
J-Global ID：201802263800986254 - 液状化砂が細い下水管内を流れる現象の再現実験
辻田佳歩; 内村太郎
Volume：53rd, 2018
J-Global ID：201802215829985002 - 地盤内に埋めた杭等の高剛性部材が地盤変位とせん断抵抗力に与える影響
大谷祐斗; 内村太郎
Volume：53rd, 2018
J-Global ID：201802289981382225 - 斜面表層の傾斜の経時データに基づく表層すべりの発生予測
XIE Ji-ren; 内村太郎
Volume：15th, 2018
J-Global ID：201902231080578565 - 多重せん断土槽で再現した斜面表層崩壊の予兆変形の進み方
福原誠; 内村太郎; TAO Shangning; 高橋良輔
Volume：15th, 2018
J-Global ID：201902235858955270 - 熊本地震で損傷を受けた自然斜面における亀裂の拡大と変動計測
土佐信一; 笹原克夫; 内村太郎; 平岡伸隆; 板山達至; WANG Lin; 西條敦志
Volume：57th, 2018
J-Global ID：201802285861845732 - 熊本地震で多数の亀裂が生じた斜面における傾斜変動
笹原克夫; 内村太郎; 平岡伸隆; 大類光平; 板山達至; WANG Lin; 西條敦志
Volume：56th, 2017
J-Global ID：201702253403028839 - 不飽和多層地盤の層境界を通過する浸透流に関する実験的研究
岡部祐美; TAO Shangning; 松丸貴樹; 内村太郎
Volume：52nd, 2017
J-Global ID：201702254533895674 - 斜面の表層崩壊の前兆としての地盤内の弾性波伝播の変化
内村太郎; CHEN Y.L.; TAO S.N.; XIE J.R.; HUANG D.
Volume：52nd, 2017
J-Global ID：201702235926709062 - 一面せん断模型実験を用いた斜面の表層変位による崩壊予測方法の検討
大原勇; WITHANAGE Kapila Ranjith; 内村太郎
Volume：52nd, 2017
J-Global ID：201702232176693636 - 多点計測による2016年熊本地震の被災斜面における傾斜及び土壌水分変化の長期観測
WANG L.; SU L.; 西江俊作; 内村太郎; TAO S.N.
Volume：52nd, 2017
J-Global ID：201702245447844964 - 仮設時に使用可能な地山補強と計測に関する実大規模崩壊実験
平岡伸隆; 吉川直孝; 副田尚輝; 伊藤和也; 笹原克夫; 内村太郎; 芳賀博文; 王林; 土佐信一; 板山達至
Volume：72nd, 2017
J-Global ID：201702269425631405 - 平成28年熊本地震被災斜面における多点計測による傾斜変位及び土壌水分変化の長期観測事例
SU Ling; WANG Lin; 西江俊作; 内村太郎; TAO Shangning
Volume：14th, 2017
J-Global ID：201702284352726318 - 北川村小島地すべりにおいて多点観測で捉えた斜面表層の傾斜角速度
笹原克夫; 伊藤和也; 吉川直孝; 平岡伸隆; 内村太郎; WANG Ling; SU Ling
Volume：55th, 2016
J-Global ID：201602280911501088 - The Early Warning System of Slope Failure based on Monitoring Surface Inclination Changes and its deployment
内村太郎; WANG Lin
防災科学技術研究所研究資料, Number：405, 2016
ISSN：0917-057X, J-Global ID：201602260161198760 - 多点計測による傾斜変化と土壌水分に基づく斜面崩壊早期警報システムの検証
SU Ling; WANG Lin; 内村太郎; 笹原克夫; TAO Shangning
Volume：51st, 2016
J-Global ID：201602247548111644 - 浸透流解析による2013年伊豆大島土砂災害斜面での不飽和透水特性の一考察
松丸貴樹; 内村太郎; 萩野知
Volume：51st, 2016
J-Global ID：201602237742095109 - 斜面表層崩壊の前に現れる傾斜変位の傾向
神保慧; 内村太郎
Volume：51st, 2016
J-Global ID：201602274778665814 - 実大模型斜面を用いた斜面掘削工事による崩壊形態に関する研究
平岡伸隆; 吉川直孝; 玉手聡; 伊藤和也; 笹原克夫; 内村太郎; 岩佐直人; 芳賀博文; 王林; 土佐信一; 板山達至; 深井義広
Volume：71st, 2016
J-Global ID：201602275819182346 - 人工軟岩の有効拘束圧の除荷による強度低下の検討
濱田悠貴; 内村太郎
Volume：51st, 2016
J-Global ID：201602218164251242 - 伊豆大島の火山性堆積斜面における雨水浸透過程
萩野知; 内村太郎
Volume：50th, 2015
J-Global ID：201502209909031610 - 斜面変状の多点監視:機器の開発とその有効性の検討
衛藤一平; 内村太郎; CHEN Yulong; WANG Lin
Volume：50th, 2015
J-Global ID：201502216979772842 - 斜面表層の傾斜変位の多点計測による崩壊予兆の監視
内村太郎; WANG Lin; 山口弘志; 西江俊作; 衛藤一平; 衛藤一平; TAO Shangning
Volume：2015, 2015
J-Global ID：201602246046494046 - 浸透流解析による2013年伊豆大島土砂災害での斜面内の降雨浸透の評価
松丸貴樹; 萩野知; 内村太郎
Volume：12th, 2015
J-Global ID：201602202857299395 - 伊豆大島の斜面内における一次元雨水浸透過程
萩野知; 内村太郎
Volume：12th, 2015
J-Global ID：201602218171050041 - 基礎工におけるモニタリングとその活用 多点における傾斜角の常時計測による斜面崩壊監視システムの概要と事例
西江俊作; WANG Lin; 内村太郎; 笹原克夫
Volume：43, Number：11, 2015
ISSN：0285-5356, J-Global ID：201502202441846640 - 多点計測による傾斜変化及び土壌水分に基づく斜面崩壊の早期警報システム
SU Ling; WANG Lin; 内村太郎
Volume：12th, 2015
J-Global ID：201602207597253878 - 薬液注入による既設埋設管の液状化時の浮上防止 (特集 地中インフラストラクチャーの維持管理)
内村 太郎; 東畑 郁生; 大坪 正英
Volume：42, Number：7, First page：94, Last page：96, Jul. 2014
Japanese
ISSN：0285-5356, J-Global ID：201402229637684166, CiNii Articles ID：40020146888, CiNii Books ID：AN00051654 - Early Warning of Slope Failure Based on Monitoring of Tilt Angles
Uchimura Taro; Towhata Ikuo; Wang Lin; Yamaguchi Hiroshi; Nishie Shunsaku
Volume：62, Number：2, First page：4, Last page：7, Feb. 2014
Japanese
ISSN：1882-7276, J-Global ID：201402214010967734, CiNii Articles ID：110009804403, CiNii Books ID：AA12312210 - DEVELOPMENT OF THE MONITORING SYSTEM THAT OPERATES WITH THE POWER GENERATED FROM THE BRIGDE VIBRATION
吉田善紀; 小林裕介; 内村太郎
土木学会論文集 A1(構造・地震工学)(Web), Volume：70, Number：2, 2014
ISSN：2185-4653, J-Global ID：201402271288350227 - 伊豆大島における台風26号災害での崩壊土と非崩壊土の土質物理試験結果の比較
秋間健; 東畑郁生; 内村太郎; 王功輝; 衛藤一平
Volume：49th, 2014
J-Global ID：201402208703927647 - 伊豆大島土石流災害の源頭崩壊部における表層計測機器の設置事例
菅野瑞穂; 瀬古一郎; 西江俊作; WANG Lin; 山口弘志; 内村太郎
Volume：49th, 2014
J-Global ID：201402215657400155 - 地すべり斜面変動と降雨量・地下水位の関係についての検討
WANG L.; 瀬古一郎; 西江俊作; 山口弘志; 内村太郎; 東畑郁生
Volume：49th, 2014
J-Global ID：201402254570193728 - 簡易動的コーン貫入試験の衝撃を使った斜面表層の弾性波探査
清水彰久; 内村太郎
Volume：49th, 2014
J-Global ID：201402270723915650 - セメント系構築物と周辺地盤の化学的相互作用研究小委員会(345委員会)成果報告書
小峯秀雄; 坂井悦郎; 名和豊春; 前川宏一; 石田哲也; 半井健一郎; 乾徹; 蔵重勲; 斎藤豪; 芳賀和子; 細川佳史; 吉田亮; 浅本晋吾; 五十嵐豪; 伊代田岳史; 入江正明; 上田隆雄; 上田洋; 内村太郎; 梅村靖弘; 枝松良展; 大石幹太; 大和田仁; 川本健; 菊地道生; 木ノ村幸士; 清田正人; 黒澤進; 桑野玲子; 小高猛司; 酒井雄也; 佐藤周之; 杉橋直行; 杉山大輔; 須田裕哉; 高橋佑弥; 取違剛; 中村弘典; 二戸信和; 庭瀬一仁
Number：103, 2014
J-Global ID：201502242272304516 - 施工中の斜面崩壊による労働災害防止のためモニタリングに関する実地観測事例~テンシオメータ・土壌水分計による計測結果と傾斜変化の関係~
伊藤和也; 笹原克夫; 芳賀博文; 土佐信一; 南雲政博; 内村太郎; 王林; 矢野真妃
Volume：2013, Number：B, 2013
ISSN：2187-7696, J-Global ID：201302233030846434 - 表層の傾斜変位による斜面崩壊の警戒と早期警報
内村太郎; 東畑郁生; 王林; 西江俊作; QIAO Jian-Ping
Volume：2013, Number：B, 2013
ISSN：2187-7696, J-Global ID：201302272849417430 - 切土中の斜面崩壊による労働災害防止のための計測-その2:現場での計測結果-
笹原克夫; 伊藤和也; 内村太郎; 宮本卓也; 井上太郎; 南雲政博; 土佐信一; 矢野真妃; 関鉄兵; 西條敦志; 芳賀博文; WANG Lin
Volume：52nd, 2013
J-Global ID：201302209756953037 - 閉端杭の多層地盤への圧入抵抗力に関する模型実験
真壁央稔; 内村太郎; 長井宏平; 石原行博; 尾川七瀬; 西川舞; 岡田浩一
Volume：48th, 2013
J-Global ID：201302209372478722 - 自然斜面の降雨崩壊実験における斜面傾斜と斜面変位についての検討
WANG L.; 瀬古一郎; 西江俊作; 内村太郎; 東畑郁生; QIAO JP.
Volume：48th, 2013
J-Global ID：201302291795982883 - 貫入式応力センサーの地盤モニタリングへの適用
清水彰久; 内村太郎; WANG Lin; 笹原克夫
Volume：48th, 2013
J-Global ID：201302292695534081 - Field measurements and monitoring for prevention of the labour accident by the slope failure under construction - Case study in Kokita-gawa check dam construction, Kochi -
伊藤和也; 笹原克夫; 芳賀博文; 土佐信一; 南雲政博; 内村太郎; 王林; 矢野真妃
地盤工学ジャーナル(Web), Volume：8, Number：4, 2013
ISSN：1880-6341, J-Global ID：201402287133067190 - 埋設管路の液状化被害軽減に関する実験-薬液注入工法の利用-
志村雅仁; 大坪正英; 内村太郎; 東畑郁生; 後藤茂
Volume：48th, 2013
J-Global ID：201302242422166090 - 下水管路の液状化被害軽減技術の開発
東畑郁生; 内村太郎; 大坪正英; 志村雅仁; LIU Bangan; 後藤茂; 林田敏彦
Volume：36, Number：9, 2013
ISSN：0387-6926, J-Global ID：201302269382762073 - 基礎工における情報通信技術(ICT)の活用 MEMS技術と特定小電力無線技術を利用した斜面災害早期警報システム
WANG Lin; 内村太郎; 西江俊作; 瀬古一郎; QIAO Jianping
Volume：40, Number：5, 2012
ISSN：0285-5356, J-Global ID：201202233610837729 - 基礎工における情報通信技術(ICT)の活用 トンネル状態把握のためのセンサーネットワーク
内村太郎; 小林裕介; 曽我健一
Volume：40, Number：5, 2012
ISSN：0285-5356, J-Global ID：201202286246652854 - 施工中の斜面崩壊による労働災害防止のためのモニタリングに関する実地観測
伊藤和也; 笹原克夫; 芳賀博文; 土佐信一; 南雲政博; 内村太郎; 王林; 矢野真妃
Volume：2012, 2012
ISSN：2187-7696, J-Global ID：201202296689831692 - 土のセメンテーションと調湿性能の関係性及び住宅壁材料への適応性
田中宏行; 内村太郎
Volume：47th, 2012
J-Global ID：201202261917493168 - 斜面表層変動監視を対象とした警報システムとその現場実証実験について
WANG L.; 西江俊作; 瀬古一郎; 内村太郎; 東畑郁生; QIAO JP.
Volume：47th, 2012
J-Global ID：201202243257919606 - 自然斜面の人工降雨による崩壊実験における崩壊前の傾斜変位
岡田直人; 内村太郎; GETIE Gizachew; SEO Hongkwan; 東畑郁生; WANG Lin; 西江俊作; 瀬古一郎; QIAO Jian Ping
Volume：47th, 2012
J-Global ID：201202259086678927 - 実物大軌道模型を用いた振動台試験によるPSB軌道の耐震性の検証
村本勝己; 櫻井祐; 荒木豪; 飯尾正俊; 阿部正直; 内村太郎
Volume：67th, 2012
J-Global ID：201202266721326486 - 表層アンカータイプPSB軌道の繰返し載荷試験
飯島正敏; 村本勝己; 櫻井祐; 中村貴久; 荒木豪; 飯尾正俊; 阿部正直; 内村太郎
Volume：67th, 2012
J-Global ID：201202272078821385 - 骨材の違いによるセメント系固化物の空隙構造の違いと調湿性能
田中宏行; 内村太郎
Volume：67th, 2012
J-Global ID：201202242429244421 - 施工中の斜面崩壊による労働災害防止のためのモニタリングに関する実地観測
伊藤和也; 笹原克夫; 芳賀博文; 土佐信一; 南雲政博; 内村太郎; 王林; 矢野真妃
Number：42, 2012
ISSN：1882-8329, J-Global ID：201302298809850688 - ICTを活用した地質調査業 斜面モニタリング装置を活用した斜面防災-迅速に設置できる小型孔内傾斜計の開発-
内村太郎; ワン リン; チャオ ジャンピン
Number：1, 2011
ISSN：0913-0497, J-Global ID：201102298926805613 - Landslides occurred by the 2011 off the Pacific coast of Tohoku Earthquake in Fukushima Pref. and Tochigi Pref.
笹原克夫; 内村太郎; 中井真司; 向井信之; 山部哲; 柳崎剛
砂防学会誌, Volume：64, Number：2, 2011
ISSN：0286-8385, J-Global ID：201102263972390764 - 模型多層地盤への杭貫入時の地盤内変形の計測
長井宏平; 鈴木直樹; 白石琢真; 内村太郎; 石原行博; 尾川七瀬
Volume：66th, 2011
J-Global ID：201102210105830755 - 繊維系ジオグリッドの変形強度特性の経年変化
平川大貴; 田村幸彦; 内村太郎; 小川敦久; 桝尾孝之; 古関潤一; 龍岡文夫
Volume：66th, 2011
J-Global ID：201102288824561005 - 堤防が崩壊する過程の法面内部の変位と弾性波速度
可児健; 鈴木大健; 内村太郎; 森啓年; 齋藤由紀子
Volume：46th, 2011
J-Global ID：201102202068522430 - 斜面の水分量と変位の計測を併用した崩壊危険性のリアルタイム判定手法
鈴木大健; 内村太郎; 可児健
Volume：46th, 2011
J-Global ID：201102208502447238 - 傾斜計センサーによる砂層への杭圧入時の地盤内変形の計測
白石琢真; 長井宏平; 内村太郎; 石原行博; 尾川七瀬
Volume：46th, 2011
J-Global ID：201102266310431346 - 中国塔子坪の地すべりを対象とした小型孔内傾斜計によるモニタリング
内村太郎; 東畑郁生; WANG Lin; 西江俊作; 瀬古一郎; QIAO JianPing
Volume：46th, 2011
J-Global ID：201102238567174170 - 中国三峡ダム貯水池地すべりを対象としたモニタリングシステムとその危険予測について
WANG L.; 西江俊作; 瀬古一郎; 内村太郎; 東畑郁生; QIAO JP.
Volume：46th, 2011
J-Global ID：201102286835249426 - 東北地方太平洋沖地震による福島県白河市の地すべり性崩壊について
中井真司; 笹原克夫; 内村太郎; 向井信之; 山部哲; 柳崎剛
Volume：2011, 2011
J-Global ID：201402299135232766 - 豪雨による地盤災害と対策 斜面災害のモニタリング
内村太郎; 瀬古一郎
Volume：39, Number：7, 2011
ISSN：0285-5356, J-Global ID：201102275523214275 - 土砂災害の2次被害を防止するための安価で迅速に設置できる監視装置の開発
内村太郎; 山田卓
Volume：2011, 2011
J-Global ID：202202268457696536 - Simple monitoring method for precaution of landslides watching tilting and water contents on slopes surface
Taro Uchimura; Ikuo Towhata; Trinh Thi Lan Anh; Jou Fukuda; Carlos J. B. Bautista; Lin Wang; Ichiro Seko; Taro Uchida; Akira Matsuoka; Yosuke Ito; Yuichi Onda; Sho Iwagami; Min-Seok Kim; Naoki Sakai
LANDSLIDES, Volume：7, Number：3, First page：351, Last page：357, Sep. 2010
A low-cost and simple monitoring method for early warning of landslides is proposed. To detect abnormal deformation of a slope, this method employs a tilt sensor in place of an extensometer on the slope surface. In order to examine the relevance of measuring rotation angle on a slope surface by tilt sensor, model tests were conducted, and rotation on the slope surface was observed together with slide displacement along the surface. The rotation data responded 30 min before failure in a model test, which could be useful as a signal for early warning. However, the behavior of rotation before failure varies from case to case, and thus, criteria to issue warning should be defined more carefully. For a model slope made of uniform loose sand, measurement of slide displacement along the slope surface is sensitive to failure at the toe, while the measurement of rotation on the slope surface is useful to detect the development of progressive failure upward along the slope. Wireless sensor units with microelectromechanical systems (MEMS) tilt sensor and volumetric water content sensor were also examined on a real slope in Kobe City, and a long-term monitoring was attempted. A simple but possible way to define the criteria of judgment to issue warning can be proposed based on combination of data obtained by the tilt sensors and volumetric water content sensors.
SPRINGER HEIDELBERG, English
DOI：https://doi.org/10.1007/s10346-009-0178-z
DOI ID：10.1007/s10346-009-0178-z, ISSN：1612-510X, Web of Science ID：WOS:000280845600012 - EFFECTS OF DRY DENSITY AND GRAIN SIZE DISTRIBUTION ON SOIL-WATER CHARACTERISTIC CURVES OF SANDY SOILS
Chaminda Pathma Kumara Gallage; Taro Uchimura
SOILS AND FOUNDATIONS, Volume：50, Number：1, First page：161, Last page：172, Feb. 2010
The soil-water characteristic curve (SWCC) of soil plays the key roll in unsaturated soil mechanics which is a relatively new field of study having wide applications particularly in Geotechnical and Geo-environmental Engineering. To encourage the geotechnical engineers to apply unsaturated soil mechanics theories in routine practice, numerical methods, based on the SWCC and saturated soil properties, have been developed to predict unsaturated permeability function and unsaturated shear strength properties which are expensive and time consuming to measure in laboratories. Further, several methods have been proposed to predict the SWCC in order to avoid difficulties in measuring the SWCC in laboratories. It is time consuming and it may require special techniques or apparatus to measure the SWCC in laboratories. However, it is important to have laboratory measured data of SWCCs to enhance and verify the proposed numerical methods. Hence, employing a Tempe pressure cell apparatus, the present study aims to investigate the effects of dry density and grain-size distribution on the SWCCs of sandy soils. Drying and wetting SWCCs were obtained for four sandy soils with different dry densities. The test data were best-fitted using the Fredlund and Xing (1994) equation and found that the fitting parameter, a, increases linearly with increasing the air-entry value of the SWCC and the fitting parameter, in, decreases with increasing the residual suction of the SWCC. The results revealed that soils with a low density have lower air-entry value and residual suction than soils with a high dry density. Further, the maximum slope of drying SWCC and hysteresis of drying and wetting SWCCs decrease with increasing density of soil. The air-entry value, residual suction, and hysteresis (the difference between the drying and wetting SWCCs) tends to decrease when the effective D(10) of the soil increases. A soil with uniform grain-size distribution (the steeper slope in grain-size distribution) has a less hysteresis and a greater slope of drying SWCC than those of a non-uniform soil.
JAPANESE GEOTECHNICAL SOC, English
DOI：https://doi.org/10.3208/sandf.50.161
DOI ID：10.3208/sandf.50.161, ISSN：0038-0806, CiNii Articles ID：80020921696, Web of Science ID：WOS:000277878400012 - 土砂災害の2次被害防止のための迅速に設置可能な監視装置の開発
王林; 西江俊作; 内村太郎; 山田卓; 内田太郎; 秋山浩一
Volume：2010, 2010
ISSN：2187-7696, J-Global ID：201002219925293410 - 降雨時のモニタリングデータを用いた斜面の排水特性評価
田中良平; 内村太郎; 山田卓
Volume：45th, Number：2, 2010
ISSN：1342-2863, J-Global ID：201002229632736274 - 貫入ロッドに組み込まれた迅速に設置できる小型孔内傾斜計の開発
竹下一輝; 内村太郎; 山田卓; 西江俊作; WANG L.; 内田太郎
Volume：45th, Number：1, 2010
ISSN：1342-2863, J-Global ID：201002270517055174 - 鋼鉄道橋における部材の振動発電を利用したモニタリングシステムの構築
吉田善紀; 小林裕介; 内村太郎
Volume：65th, 2010
J-Global ID：201002213970899207 - 現地計測を利用した斜面崩壊時期リアルタイム予測手法設計の試み
鈴木大健; 内村太郎; 田中良平; 山田卓
Volume：7th, 2010
J-Global ID：201102212359435158 - Landslides: a review of achievements in the first 5 years (2004-2009)
Kyoji Sassa; Satoshi Tsuchiya; Keizo Ugai; Akihiko Wakai; Taro Uchimura
LANDSLIDES, Volume：6, Number：4, First page：275, Last page：286, Dec. 2009
The international journal Landslides was initiated in April 2004. It is the core project (IPL-C100) of the International Programme on Landslides, a joint initiative of the International Consortium on Landslides and the United Nations and other global organizations. The aims of Landslides are to promote landslide sciences, technology, and capacity building and strengthen global cooperation for landslide risk reduction within the United Nations International Strategy for Disaster Reduction. This paper presents an analysis of the first 5 years of Landslides, the study methods employed, the types and major causes of landslides, the number of different contributors per country, and the "times cited" per issue and most frequently cited papers and briefly discusses some of these. Strategies for future development of the journal involve obtaining input and suggestion from researchers and readers worldwide.
SPRINGER HEIDELBERG, English, Book review
DOI：https://doi.org/10.1007/s10346-009-0172-5
DOI ID：10.1007/s10346-009-0172-5, ISSN：1612-510X, Web of Science ID：WOS:000272159800002 - PREPARATION OF WATER-SATURATED BENTONITE SAMPLES AND THEIR USE IN TORSION SHEAR TESTS
Misako Nakamura; Kenichi Kawano; Bach Thuan Thai; Taro Uchimura; Keiichi Sugo; Ikuo Towhata
SOILS AND FOUNDATIONS, Volume：49, Number：6, First page：981, Last page：991, Dec. 2009
The present study concerns cyclic shear tests on water-saturated bentonite samples. Since the tested bentonite is of sodium type, it absorbs water remarkably, and hence it is difficult and time-consuming to consolidate it for shear tests. This difficulty was overcome by inventing a new consolidation tank in which the drainage path is significantly shortened, and consequently the consolidation time is shortened. Cyclic torsion shear tests were performed on thus-prepared specimens to examine the variation of shear modulus and damping ratio with increasing shear strain amplitude. Moreover, cyclic shear stress was applied on an anisotropically consolidated specimen to demonstrate that permanent distortion of bentonite is small even during a very strong earthquake loading.
JAPANESE GEOTECHNICAL SOC, English
DOI：https://doi.org/10.3208/sandf.49.981
DOI ID：10.3208/sandf.49.981, ISSN：0038-0806, CiNii Articles ID：110007641865, Web of Science ID：WOS:000275036000012 - 斜面変動のリアルタイムモニタリングシステムの開発と実証 その2
福田穣; 内村太郎; WANG Lin; 瀬古一郎; 内田太郎; 伊藤洋輔; 恩田裕一; 岩上翔; KIM Min‐seok; 酒井直樹
地盤工学研究発表会発表講演集, Volume：44th, First page：1719, Last page：1720, 13 Jul. 2009
Japanese
ISSN：1342-2863, J-Global ID：200902252209651700 - THE P2S EFFECT ON THE ACCUMULATION OF RESIDUAL STRAINS IN SOFT ROCKS DUE TO IRREGULAR CYCLIC LOADING
D. C. Peckley; Taro Uchimura
SOILS AND FOUNDATIONS, Volume：49, Number：1, First page：63, Last page：74, Feb. 2009
Data and information on the cyclic loading behaviour of soft rocks, especially behaviour under irregular cyclic loading, are very limited. This paper shows that the present procedure of estimating residual strain accumulation due to irregular cyclic loading using a fatigue model from uniform amplitude cyclic loading can result in underestimated residual strains. Such underestimation occurs because the present procedure fails to take into account the so-called P2S effect on the softening behaviour of soft rocks under cyclic loading. The parameter P2S is defined as the sum of the magnitudes of the increments in residual strains due to the previous two loading half-cycles. When P2S is large, a large residual strain increment can be expected. This paper also shows that taking the P2S effect into account can improve the simulation of residual strain accumulation due to irregular cyclic loading.
JAPANESE GEOTECHNICAL SOC, English
DOI：https://doi.org/10.3208/sandf.49.63
DOI ID：10.3208/sandf.49.63, ISSN：0038-0806, CiNii Articles ID：110007327427, Web of Science ID：WOS:000265325700005 - STRENGTH AND DEFORMATION OF SOFT ROCKS UNDER CYCLIC LOADING CONSIDERING LOADING PERIOD EFFECTS
D. C. Peckley; Taro Uchimura
SOILS AND FOUNDATIONS, Volume：49, Number：1, First page：51, Last page：62, Feb. 2009
Cost-effective design is the primary motivation for adopting the performance-based design method. This method, however, requires that deformations be reliably estimated. While soft rocks are known to be competent foundation materials for large-scale structures, the deformation characteristics of this material when subjected to large cyclic loadings still have to be understood. In this study, the strength and deformation characteristics of soft rocks under cyclic loadings were investigated by conducting cyclic triaxial tests on natural soft rock samples. The loading histories that were applied to these samples were uniform amplitude cyclic loadings with loading periods between 1 s and 9000 s. The tests revealed that the longer the loading period, the larger is the residual strain accumulated for a certain number of loading cycles. This dependency of residual strain accumulation on loading period appears to be an intrinsic material property which is irrespective of loading amplitude and water content. From this finding, it can be inferred that the prevailing practice of soft rock cyclic loading tests at 300 s and 9000 s of cyclic loading periods, which are much longer than that of earthquakes, can result in overestimated residual strains.
JAPANESE GEOTECHNICAL SOC, English
DOI：https://doi.org/10.3208/sandf.49.51
DOI ID：10.3208/sandf.49.51, ISSN：0038-0806, CiNii Articles ID：110007327429, Web of Science ID：WOS:000265325700004 - リアルタイム斜面監視システム構築のための斜面崩壊検知センサー開発
瀬古一郎; 王林; 内村太郎; 東畑郁生; 田村圭司; 内田太郎; 伊藤洋輔
Volume：2009, 2009
ISSN：2187-7696, J-Global ID：200902253224842667 - 矢板の圧入が地中構造物と埋設管に及ぼす土圧の変化 その1
内村太郎; 田實渉; 前川宏一; 長井宏平; 酒井雄也
Volume：44th, 2009
ISSN：1342-2863, J-Global ID：200902229230305179 - 矢板の圧入が地中構造物と埋設管に及ぼす土圧の変化 その2
内村太郎; 田實渉; 前川宏一; 長井宏平; 酒井雄也
Volume：44th, 2009
ISSN：1342-2863, J-Global ID：200902292233504494 - 斜面変動のリアルタイムモニタリングシステムの開発と実証 その1
瀬古一郎; WANG L.; 福田穣; JOSE Carlos; 内村太郎; 内田太郎; 伊藤洋輔
Volume：44th, 2009
ISSN：1342-2863, J-Global ID：200902233448164868 - 弾性波速度を使った斜面の不飽和地盤の水分量と安定度の監視
香川沙絵; 内村太郎
Volume：44th, 2009
ISSN：1342-2863, J-Global ID：200902294248630332 - コンクリート‐地盤境界問題研究小委員会(332)報告書―コンクリート‐地盤境界問題に関する現状と課題―
牧剛史; 内村太郎; 半井健一郎; 入江正明; 小里好臣; 桑野玲子; 坂井康伸; 住吉卓; 滝沢聡; 福浦尚之; 吉本正浩; 渡辺健治; 渡邉弘行
コンクリート技術シリーズ, Number：77, First page：73P, 20 Feb. 2008
Japanese
J-Global ID：200902256013051654 - 弾性波速度の変化を使った地盤斜面の土壌水分量の監視
鈴木敬之; 香川沙絵; 内村太郎
Volume：43rd, 2008
ISSN：1342-2863, J-Global ID：200902212176697600 - 降雨時の常時計測による斜面の水理特性の評価
生川寛之; 福田穣; 内村太郎
Volume：43rd, 2008
ISSN：1342-2863, J-Global ID：200902276046518516 - コンクリート-地盤境界問題研究小委員会(332)報告書-コンクリート-地盤境界問題に関する現状と課題-
牧剛史; 内村太郎; 半井健一郎; 入江正明; 小里好臣; 桑野玲子; 坂井康伸; 住吉卓; 滝沢聡; 福浦尚之; 吉本正浩; 渡辺健治; 渡邉弘行
Number：77, 2008
J-Global ID：200902256013051654 - セメント改良礫土を用いた軟弱地盤対策工の模型振動実験
礒野純治; 松丸貴樹; 渡辺健治; 舘山勝; 内村太郎
Volume：42nd, 2007
ISSN：1342-2863, J-Global ID：200902205141856386 - 土木における学外学習・インターンシップを考える 3 学外実習・インターンシップ-新しい取組み-Section-1 東京大学 社会基盤学専攻の海外インターンシップ
内村太郎
Volume：92, Number：2, 2007
ISSN：0021-468X, J-Global ID：200902214434615803 - セメント改良礫土の強度・変形特性に及ぼす年代効果
松丸貴樹; 渡辺健治; 礒野純治; 舘山勝; 内村太郎
Volume：42nd, 2007
ISSN：1342-2863, J-Global ID：200902236224844269 - 斜面崩壊を対象とした傾斜計によるリアルタイム危険予測
福田穣; 内村太郎; 東畑郁生; 瀬古一郎; WANG L.
Volume：42nd, 2007
ISSN：1342-2863, J-Global ID：200902236905823693 - タイヤチップスを混合した砂の液状化強度と変形
佐藤達也; NGUYEN Chi Anh; 内村太郎; 東畑郁生
Volume：42nd, 2007
ISSN：1342-2863, J-Global ID：200902252350848917 - 斜面崩壊を対象としたリアルタイム危険予測ネットワークシステムの開発
瀬古一郎; WANG L.; 内村太郎; 東畑郁生; 福田穣
Volume：42nd, 2007
ISSN：1342-2863, J-Global ID：200902254917387242 - Function of permeable geosynthetics in unsaturated embankments subjected to rainfall infiltration
E. F. Garcia; C. P. K. Gallage; T. Uchimura
GEOSYNTHETICS INTERNATIONAL, Volume：14, Number：2, First page：89, Last page：99, 2007
This paper presents laboratory tests and experiments using scale models to study the hydraulic behavior of permeable geosynthetics within unsaturated embankments subjected to rainfall infiltration. Water retention curves were measured in the laboratory in order to evaluate the unsaturated hydraulic characteristics of soil and geosynthetics. Model embankments were built using two layers of permeable geosynthetics; rainfall was simulated using an irrigation pipe. Embankments were subjected to wetting and drying processes; negative and positive pore water pressure and water contents within the model were measured. Comparison between Tempe pressure cell and hanging column test results showed that geosynthetics embedded within the soil approached saturation only when the pore water pressures of the surrounding soil were close to zero or positive. This behavior was also observed in the model tests. Local failure during the wetting processes was observed while pore water pressure increased immediately above the geosynthetic layers. In the models, where strips of geotextile were used, water could not accumulate above the geotextile, and instead drained down between strips. Strips of geotextile prevented the capillary barrier effect and allowed the free drainage of water through the embankment.
ICE PUBLISHING, English
DOI：https://doi.org/10.1680/gein.2007.14.2.89
DOI ID：10.1680/gein.2007.14.2.89, ISSN：1072-6349, eISSN：1751-7613, Web of Science ID：WOS:000245224900004 - 鉄道システムを対象とした災害・事故の早期警報/危機管理システムの研究 施設系のハイブリッド安全性評価法の確立
岸利治; 古関潤一; 石田哲也; 内村太郎
2006
J-Global ID：200902279539926728 - 小規模斜面を対象とした豪雨時の斜面監視装置の開発
TRINH Thi Lan Anh; 内村太郎
Volume：41st, 2006
ISSN：1342-2863, J-Global ID：200902226200115635 - セメント改良礫土の曲げ特性に及ぼすジオテキスタイルの効果について
渡辺健治; 松丸貴樹; 水野進正; 舘山勝; 内村太郎
Volume：61st, Number：Disk 1, 2006
J-Global ID：200902266829898901 - セメント改良補強土の梁の曲げ載荷試験
内村太郎; THAI Bach Thuan
Volume：41st, 2006
ISSN：1342-2863, J-Global ID：200902292480266466 - セメント改良盛土中に敷設されたジオテキスタイル補強材の引抜試験
渡辺健治; 舘山勝; 内村太郎
Volume：61, Number：1, 2006
J-Global ID：200902257538117741 - VERTICAL AND HORIZONTAL LOADING TESTS ON FULL-SCALE PRELOADED AND PRESTRESSED GEOGRID-REINFORCED SOIL STRUCTURES
UCHIMURA TARO; TAMURA YUKIHIKO; TATEYAMA MASARU; TANAKA IKUO; TATSUOKA FUMIO
Journal of the Japanese Geotechnical Society, Volume：45, Number：6, First page：75, Last page：88, 15 Dec. 2005
The performance of a preloaded and prestressed (PLPS) geogrid-reinforced soil pier constructed for a railway was evaluated by vertical loading tests performed after a service period of about 3.5 years. The performance was compared with those at the preloading stage during construction as well as during service. The test results confirmed that the high performance of the pier (i.e., very small transient deformation during train passing and substantially small residual deformation by long-term traffic load during service) can be attributed to the preloading and prestressing procedure. Horizontal loading tests were performed simultaneously on the top RC blocks on the preloaded-prestressed pier and the geogrid-reinforced soil abutment, which was constructed without the PLPS procedure for the same bridge. The results showed that the pier was substantially more stable against over-turning moment and horizontal shear load than the abutment, indicating that the PLPS procedure is also very effective to achieve a high seismic stability.
English
ISSN：1341-7452, CiNii Articles ID：110004062145, CiNii Books ID：AN10496056 - Vertical and horizontal loading tests on full-scale preloaded and prestressed geogrid-reinforced soil structures
T Uchimura; Y Tamura; M Tateyama; Tanaka, I; F Tatsuoka
SOILS AND FOUNDATIONS, Volume：45, Number：6, First page：75, Last page：88, Dec. 2005
The performance of a preloaded and prestressed (PLPS) geogrid-reinforced soil pier constructed for a railway was evaluated by vertical loading tests performed after a service period of about 3.5 years. The performance was compared with those at the preloading stage during construction as well as during service. The test results confirmed that the high performance of the pier (i.e., very small transient deformation during train passing and substantially small residual deformation by long-term traffic load during service) can be attributed to the preloading and prestressing procedure. Horizontal loading tests were performed simultaneously on the top RC blocks on the preloaded-prestressed pier and the geogrid-reinforced soil abutment, which was constructed without the PLPS procedure for the same bridge. The results showed that the pier was substantially more stable against over-turning moment and horizontal shear load than the abutment, indicating that the PLPS procedure is also very effective to achieve a high seismic stability.
JAPANESE GEOTECHNICAL SOC, English
DOI：https://doi.org/10.3208/sandf.45.75
DOI ID：10.3208/sandf.45.75, ISSN：0038-0806, Web of Science ID：WOS:000235047000006 - 多数回の水平微小繰返し載荷を受ける擁壁の残留土圧特性
野尻峰広; 笠原広智; 龍岡文夫; 平川大貴; 住吉卓; 新井寿和; 内村太郎
Volume：40th, 2005
ISSN：1342-2863, J-Global ID：200902202558141801 - 繰返し微小変位に伴い変形が進行したU型擁壁の事例報告
住吉卓; 平川大貴; 野尻峰広; 笠原広智; 内村太郎; 新井寿和; 龍岡文夫
Volume：40th, 2005
ISSN：1342-2863, J-Global ID：200902204066366983 - 新潟・中越地震における地滑り現場の斜面崩壊土の特性
内村太郎; 東畑郁生; 水橋正典; RAMIN Motamed
Volume：60th, Number：Disk 1, 2005
J-Global ID：200902221993261244 - セメント改良れき土の品質のバラツキに及ぼす施工方法の違いについて
松丸貴樹; 渡辺健治; 舘山勝; 富永真生; 水野進正; 内村太郎
Volume：40th, 2005
ISSN：1342-2863, J-Global ID：200902242894223931 - 土とコンクリートの中間材料の配合と締固め密度の関係
倉持裕子; BACH Thai Thuan; 内村太郎
Volume：40th, 2005
ISSN：1342-2863, J-Global ID：200902257870104629 - 補強材剛性が補強土構造物の微小繰り返し荷重とクリープ荷重による変形に与える影響
内村太郎; ANH CHI N.
Volume：40th, 2005
ISSN：1342-2863, J-Global ID：200902274502880122 - 繰返し微小変位を受ける擁壁の裏込め土を模疑した平面ひずみ試験
新井寿和; 内村太郎; 住吉卓; 龍岡文夫; 平川大貴; 野尻峰広
Volume：40th, 2005
ISSN：1342-2863, J-Global ID：200902279885967350 - 破砕コンクリートの変形強度に固化セメント成分が与える影響
高橋弘元; 内村太郎
Volume：40th, 2005
ISSN：1342-2863, J-Global ID：200902281349321310 - 中越地震・福岡西方沖地震の被害調査
木幡行宏; 内村太郎; 原田尚幸; 高橋真一; 桝尾孝之; 平川大貴; 西村淳
Volume：21, Number：2, 2005
J-Global ID：200902277521821489 - Intermediate Materials between Concrete and Geomaterials
UCHIMURA T.
Concrete Journal, Volume：2005年10月号, pp. 3-8., Number：10, First page：3, Last page：8, 2005
Concrete engineers have developed RCD and CSG methods, which use mixture materials of aggregate, cement and water with lower cement contents than usual concrete. Such materials can be filled and mechanically compacted just like soil structures. On the other hand, geotechnical engineers have developed cemented well-graded gravels as a new backfill material, in order to construct more stable soil structures. These materials are quite similar to each other in their quality of aggregate (or well-graded gravel), mixture ratio of cement and water and compaction methods. They could be classified in the same category, intermediate between concrete and soils while their concepts of mixture design, quality control and construction methods are different. This paper compares these materials, and reports some experimental results on their compaction and strength characteristics.
Japan Concrete Institute, Japanese
DOI：https://doi.org/10.3151/coj1975.43.10_3
DOI ID：10.3151/coj1975.43.10_3, ISSN：0387-1061, J-Global ID：200902211786362574, CiNii Articles ID：10016125780, CiNii Books ID：AN00094169 - Soil Dynamics and Earthquake Engineering (2)
内村 太郎
Volume：52, Number：3, First page：16, Last page：16, 01 Mar. 2004
Japanese
ISSN：0041-3798, CiNii Articles ID：110003960330, CiNii Books ID：AN0014925X - 破砕コンクリート廃材とその他の地盤材料の変形強度特性の比較
内村太郎; UMAIR A; 龍岡文夫; 松島健一; 毛利栄征
Volume：39th, 2004
ISSN：1342-2863, J-Global ID：200902261883037022 - 補強材剛性が補強土構造物の供用時の変形に与える影響
内村太郎; 水橋正典
Volume：19, 2004
ISSN：1344-6193, J-Global ID：200902274232387771 - 補強材剛性が補強土構造物の微少繰返し荷重に対する変形に与える影響
水橋正典; 内村太郎
Volume：39th, 2004
ISSN：1342-2863, J-Global ID：200902274946349202 - 擁壁の繰り返し微小変位と背面土圧
住吉卓; 山村博孝; 藤本慎也; 内村太郎; 龍岡文夫
Volume：59th, Number：Disk 1, 2004
J-Global ID：200902296878815112 - PERFORMANCE OF A PRELOADED-PRESTRESSED GEOGRID-REINFORCED SOIL PIER FOR A RAILWAY BRIDGE
UCHIMURA TARO; TATEYAMA MASARU; TANAKA IKUO; TATSUOKA FUMIO
Journal of the Japanese Geotechnical Society, Volume：43, Number：6, First page：155, Last page：171, 15 Dec. 2003
A new construction method, called "the preloaded and prestressed reinforced soil method", proposed in this paper, aims at making reinforced backfill structures very stiff and stable. To make the deformation of a reinforced backfill nearly elastic, sufficiently large preload is first applied by introducing tension into metallic tie rods that penetrate the reinforced backfill and are connected to top and bottom reaction blocks. High tensile force in the tie rods functions as prestress, increasing the confining pressure in the backfill and thus keeping the stiffness and shear strength of the backfill soil sufficiently high. In 1996, in northern Kyushu, Japan, a prototype pier of preloaded and prestressed geogrid reinforced backfill was constructed for the first time to support a pair of simple beam girders for a temporary railway bridge. An abutment of geogrid-reinforced soil retaining wall, which was neither preloaded nor prestressed, was also constructed for the same bridge by otherwise the same construction method. The behaviours of the pier and the abutment were measured during the construction and the service period of about four and a half years and subsequently full-scale loading tests were performed. It is shown that the geogrid-reinforced backfill pier became substantially stiffer against static and dynamic load by having been preloaded and being prestressed when compared to the geogridreihforced backfill abutment.
English
ISSN：1341-7452, CiNii Articles ID：110003892403, CiNii Books ID：AN10496056 - Performance of a preloaded-prestressed geogrid-reinforced soil pier for a railway bridge
T Uchimura; M Tateyama; Tanaka, I; F Tatsuoka
SOILS AND FOUNDATIONS, Volume：43, Number：6, First page：155, Last page：171, Dec. 2003
A new construction method, called "the preloaded and prestressed reinforced soil method", proposed in this paper, aims at making reinforced backfill structures very stiff and stable. To make the deformation of a reinforced backfill nearly elastic, sufficiently large preload is first applied by introducing tension into metallic tie rods that penetrate the reinforced backfill and are connected to top and bottom reaction blocks. High tensile force in the tie rods functions as prestress, increasing the confining pressure in the backfill and thus keeping the stiffness and shear strength of the backfill soil sufficiently high. In 1996, in northern Kyushu, Japan, a prototype pier of preloaded and prestressed geogrid reinforced backfill was constructed for the first time to support a pair of simple beam girders for a temporary railway bridge. An abutment of geogrid-reinforced soil retaining wall, which was neither preloaded nor prestressed, was also constructed for the same bridge by otherwise the same construction method. The behaviours of the pier and the abutment were measured during the construction and the service period of about four and a half years and subsequently full-scale loading tests were performed. It is shown that the geogrid-reinforced backfill pier became substantially stiffer against static and dynamic load by having been preloaded and being prestressed when compared to the geogrid-reinforced backfill abutment.
JAPANESE GEOTECHNICAL SOC, English
DOI：https://doi.org/10.3208/sandf.43.6_155
DOI ID：10.3208/sandf.43.6_155, ISSN：0038-0806, Web of Science ID：WOS:000189081100011 - IMPROVING THE DYNAMIC PERFORMANCE OF PRELOADED AND PRESTRESSED MECHANICALLY REINFORCED BACKFILL BY USING A RATCHET CONNECTION
SHINODA MASAHIRO; UCHIDA TARO; TATSUOKA FUMIO
Journal of the Japanese Geotechnical Society, Volume：43, Number：2, First page：33, Last page：54, 15 Apr. 2003
A series of laboratory model shaking table tests were performed to evaluate improvement of the dynamic performance of mechanically reinforced soil structures that are vertically preloaded and prestressed by using a ratchet connection for the tie rods. The preloading and prestressing (PLPS) procedure was originally developed to substantially decrease the residual settlement at the top of backfill subjected to long-term live load such as traffic load. It is shown that the maintenance of high prestress in the backfill is also essential to substantially reduce the shear and bending deformation as well as vertical compression of reinforced backfill subjected to dynamic load. For relatively slender reinforced backfill structures, the maintenance of high prestress is particularly important to restrain the occurrence of large bending deformation of backfill. For these purposes, it is proposed that the top end of the tie rods be fixed to the crest of the structure by using a ratchet connection, which allows free compression of backfill at nearly constant prestress while mechanically not allowing any expansion of backfill. It is suggested that, to avoid a resonant or nearresonant state during seismic loading, the initial value of the natural frequency f_n of a given structure be designed to be sufficiently higher than the anticipated predominant frequency f_p of given seismic load, while the f_n value during dynamic loadine is maintained at a higher valve than the f_p value by using a ratchet connection.
English
ISSN：1341-7452, CiNii Articles ID：110003892335, CiNii Books ID：AN10496056 - 微少繰返し応力に対する補強材剛性の効果
内村太郎; 龍岡文夫; 平川大貴; 高岡秀明
Volume：38th, 2003
ISSN：1342-2863, J-Global ID：200902217292386754 - PL・PS補強土橋台の限界状態設計法の提案
舘山勝; 篠田昌弘; 龍岡文夫; 内村太郎; 矢崎澄雄
Volume：58th, Number：Disk 1, 2003
J-Global ID：200902274887312154 - PL・PS補強土橋台の限界状態設計法による試計算結果
鴇田由希; 舘山勝; 内村太郎; 龍岡文夫; 篠田昌弘
Volume：58th, Number：Disk 1, 2003
J-Global ID：200902280447944434 - セメント改良粒調砕石盛土に敷設されたジオグリッド補強材のクリープ・引抜き特性試験
内村太郎; 龍岡文夫; 青木一二三; 米沢豊司; 北野陽堂
Volume：58th, Number：Disk 1, 2003
J-Global ID：200902276831036890 - Increasing the stiffness of mechanically reinforced backfill by preloading and prestressing
Masahiro Shinoda; Taro Uchimura; Fumio Tatsuoka
Soils and Foundations, Volume：43, Number：1, First page：75, Last page：92, 2003
A new construction procedure applying a large preload to a mechanically reinforced backfill structure and keeping a large prestress while the structure is in service is described. This construction procedure was developed to substantially decrease transient and residual compression of reinforced backfill by long-term vertical cyclic loading, such as traffic load. A very high performance for about four and a half years of a prototype railway bridge pier of preloaded and prestressed geogrid-reinforced gravel backfill, which validated the advantages of this construction procedure, is described. A series of model loading tests performed in the laboratory to find the relevant preloading and prestressing procedure are described. It is shown that the transient and residual compression of reinforced backfill by vertical cyclic loading can be made very small by preloading the reinforced backfill and then decreasing the load level to a prestress level that is about a half of the preload level, while keeping the difference between the preload and prestress levels sufficiently larger than the amplitude of subsequently applied cyclic load. Effects of different combinations of backfill soil type and reinforcement material, the use of tie rods and the application of pre-cyclic preloading are reported. Negative effects of the swelling of backfill during unloading are discussed.
Japanese Geotechnical Society, English, Book review
DOI：https://doi.org/10.3208/sandf.43.75
DOI ID：10.3208/sandf.43.75, ISSN：0038-0806, SCOPUS ID：24744454631 - Ground Improvement Including Geosynthetics
内村 太郎
Volume：50, Number：3, First page：35, Last page：35, 01 Mar. 2002
Japanese
ISSN：0041-3798, CiNii Articles ID：110003969141, CiNii Books ID：AN0014925X - Ground Improvement and Reinforcement
内村 太郎
Volume：50, Number：3, First page：25, Last page：25, 01 Mar. 2002
Japanese
ISSN：0041-3798, CiNii Articles ID：110003969132, CiNii Books ID：AN0014925X - PL・PS工法の新しい展開 (特集 擁壁・補強土壁工法)
内村 太郎; 龍岡 文夫; 舘山 勝
Volume：57, Number：2, First page：62, Last page：68,13, Feb. 2002
Japanese
ISSN：0285-5046, J-Global ID：200902160948924489, CiNii Articles ID：40002745099, CiNii Books ID：AN00174891 - PL・PS補強土橋台の三次元模型振動台実験
半井健一郎; 渡辺健治; 舘山勝; 内村太郎; 龍岡文夫
Volume：17, 2002
ISSN：1344-6193, J-Global ID：200902142161420400 - 高分子補強材の変形強度特性に対する材料粘性の効果
平川大貴; KONGKITKUL W; 龍岡文夫; 内村太郎
Volume：17, 2002
ISSN：1344-6193, J-Global ID：200902186187294590 - 基礎構造における震動制御の工夫 補強土工法における地震エネルギー消費 免震構造としてのPLPSジオテキスタイル補強土
古谷明寿; 半井健一郎; 内村太郎; 龍岡文夫
Volume：30, Number：12, 2002
ISSN：0285-5356, J-Global ID：200902106221194980 - プレローディド・プレストレスト(PL・PS)補強土橋台の設計法に基づく試設計例
矢崎澄雄; 山田孝弘; 舘山勝; 内村太郎; 龍岡文夫
Volume：37th, 2002
ISSN：1342-2863, J-Global ID：200902108384093261 - クリープ・繰り返し載荷時におけるジオテキスタイル補強土構造物の変形特性
平川大貴; 柴田芳雄; 龍岡文夫; 内村太郎
Volume：37th, 2002
ISSN：1342-2863, J-Global ID：200902110244841122 - 実施工PL・PS補強土橋脚の鉛直荷重による圧縮変形
内村太郎; 龍岡文夫; 舘山勝; 小島謙一; 兵藤公顕
Volume：37th, 2002
ISSN：1342-2863, J-Global ID：200902139163026309 - プレローディド・プレストレスト補強土構造物の適切な初期プレストレス値について
本田聖一朗; 半井健一郎; 内村太郎; 龍岡文夫
Volume：37th, 2002
ISSN：1342-2863, J-Global ID：200902139848763306 - 免震構造としてのPLPSジオテキスタイル補強土の振動台実験
古谷明寿; 半井健一郎; 内村太郎; 龍岡文夫
Volume：37th, 2002
ISSN：1342-2863, J-Global ID：200902147715303810 - 実施工PL・PS補強土橋脚の水平載荷試験
田村幸彦; 舘山勝; 小島謙一; 龍岡文夫; 内村太郎; 兵藤公顕
Volume：37th, 2002
ISSN：1342-2863, J-Global ID：200902186469462429 - プレローディド・プレストレスト(PL・PS)補強土橋台の限界状態設計法に関する基礎的検討
山田孝弘; 舘山勝; 矢崎澄雄; 内村太郎; 龍岡文夫
Volume：37th, 2002
ISSN：1342-2863, J-Global ID：200902195499261931 - 鉄道における最近の基礎工技術 PL・PS補強土橋脚の施工と載荷試験
藤原直紀; 内村太郎; 田中郁夫; 坂口博文
Volume：30, Number：11, 2002
ISSN：0285-5356, J-Global ID：200902199997697440 - Evaluation of Stiffness of Soft Clay Fill Improved by Cement-Mixing
SUGAI Masazumi; TATUOKA Fumio; UCHIMURA Tarou; SUGOU Keiichi
土と基礎, Volume：49, Number：5, First page：22, Last page：24, 01 May 2001
The deformation of a fill made of cement-mixed soft marine clay was evaluated based on the results of special triaxial compression tests. Simulating the stress path and loading time history in the field, a sequence of anisotropic compression and four days drained creep was repeated, lasting 44 days in total. The axial strains were measured locally. The test results were consistent with the measured compression of the fill but standard oedometer test results over-estimated it. Development of a high stiffness zone around the creep stress state and creep deformation is a key in the deformation prediction. A high stiffness behaviour of the fill, when loaded after drained creep with curing, is suggested.
Japanese
ISSN：0041-3798, J-Global ID：200902153651448614, CiNii Articles ID：110003969010, CiNii Books ID：AN0014925X - プレローディド・プレストレスト補強土橋台の模型振動実験
半井健一郎; 篠田昌弘; 渡辺健治; 館山勝; 内村太郎; 龍岡文夫
Volume：36th, 2001
ISSN：1342-2863, J-Global ID：200902121754241121 - プレローディド・プレストレスト補強土模型の荷重保持載荷実験
柴田芳雄; 平川大貴; 篠田昌弘; 内村太郎; 龍岡文夫
Volume：56th, Number：B, 2001
J-Global ID：200902167262224809 - PL・PS補強土構造物の動的挙動に及ぼすラチェット機能付きプレストレス繊維装置の効果
篠田昌弘; 山本俊太; 夏木敏広; 内村太郎; 龍岡文夫
Volume：36th, 2001
ISSN：1342-2863, J-Global ID：200902168478171714 - PLPS補強土橋台の耐震性に対するプレストレス維持の重要性
内村太郎; 龍岡文夫; 半井健一郎; 篠田昌弘; 舘山勝; 渡辺健治
Volume：56th, Number：B, 2001
J-Global ID：200902172072605222 - 不規則波加振時のPLPS補強土橋台におけるラチェット装置の有効性
半井健一郎; 篠田昌弘; 渡辺健治; 館山勝; 内村太郎; 龍岡文夫
Volume：56th, Number：B, 2001
J-Global ID：200902180118216520 - 補強盛土のプレロード時のクリープ圧縮の解析
内村太郎; SIDDIQUEE M S A; 龍岡文夫; 舘山勝
Volume：36th, 2001
ISSN：1342-2863, J-Global ID：200902183277271680 - 共振時におけるPL・PS補強土構造物の耐震性
山本俊太; 篠田昌弘; 夏木敏広; 内村太郎; 龍岡文夫
Volume：36th, 2001
ISSN：1342-2863, J-Global ID：200902197409501397 - CYCLIC AND CREEP LOADING IN VERTICAL DIRECTION ON A PLPS REINFORCED SOIL BRIDGE PIER
UCHIMURA T.; TATEYAMA M.; TANAKA I.; TATSUOKA F.
Geosynthetics Engineering Journal, Volume：vol.16, pp. 147-154, First page：147, Last page：154, 2001
The first prototype reinforced soil bridge pier was constructed by means of preloaded and prestressed (PLPS) reinforced soil method, which aims at substantially increasing the stiffness of a geosynthetic-reinforced soil embankment by vertical preloading and prestressing. After the usage for a period of three and half years, cyclic and creep loading tests in the vertical direction were performed on this pier before its destruction work. In this paper, the deformation characteristics of the PLPS structures are discussed based on behaviours of the pier during the construction, the service period, and the final loading tests.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.16.147
DOI ID：10.5030/jcigsjournal.16.147, ISSN：1344-6193, J-Global ID：200902180035469826, CiNii Articles ID：130003450717 - CONSTANT PRESSURE AND CONSTANT VOLUME DIRECT SHEAR TESTS ON REINFORCED SAND
QIU Jin-ying; TATSUOKA Fumio; UCHIMURA Taro
Journal of the Japanese Geotechnical Society, Volume：40, Number：4, First page：1, Last page：17, 15 Aug. 2000
In order to investigate the deformation and strength characteristics of reinforced sand, a series of relatively large-inscale direct shear tests was performed. Phosphor bronze strips and sheets with different configurations were used as reinforcement to study the effects of the shape and dimensions of reinforcement. Constant pressure tests and constant volume tests were conducted with different forms of reinforcement and different values of stiffness, surface area, spatial dispersion and surface friction. Test results show that for a given amount of reinforcement material, the reinforcing efficiency is higher with reinforcement having a larger surface area, a rougher surface texture and a larger degree of dispersion. The dilatancy at the residual state depends on the reinforcement property and geometry, and it is larger in more effectively reinforced sand with a larger shear zone. More dilative characteristics of reinforced soil results in larger shear strength under constant volume conditions at large strains.
English
ISSN：1341-7452, CiNii Articles ID：110003946222, CiNii Books ID：AN10496056 - 台湾集集地震における擁壁・補強土構造物の被害調査
内村太郎; 古関潤一; 龍岡文夫; 早野公敏; 黄景川
Volume：16, Number：1, 2000
J-Global ID：200902112437829092 - 補強土の耐震性に対するプレロード,プレストレスの効果
石村隆敏; 篠田昌弘; 中村俊朗; 内村太郎; 龍岡文夫
Volume：35th, 2000
ISSN：1342-2863, J-Global ID：200902135266273376 - セメント改良粘土の原位置応力履歴における変形特性
菅井正澄; 藤山哲雄; 内村太郎; 龍岡文夫
Volume：35th, 2000
ISSN：1342-2863, J-Global ID：200902136271223375 - PL・PS補強土橋脚の動的特性
篠田昌弘; 石村隆敏; 中村俊朗; 内村太郎; 龍岡文夫
Volume：35th, 2000
ISSN：1342-2863, J-Global ID：200902166339574984 - 台湾集集地震における擁壁・補強土構造物への被害事例 (その2)
古関潤一; 早野公敏; 龍岡文夫; 内村太郎
Volume：35th, 2000
ISSN：1342-2863, J-Global ID：200902166582655488 - プレローディド・プレストレスト補強土橋台の模型振動台実験
中村俊朗; 篠田昌弘; 石村隆敏; 内村太郎; 龍岡文夫
Volume：35th, 2000
ISSN：1342-2863, J-Global ID：200902176799473863 - 台湾集集地震における擁壁・補強土構造物への被害事例 (その1)
内村太郎; 龍岡文夫; 古関潤一; 早野公敏
Volume：35th, 2000
ISSN：1342-2863, J-Global ID：200902193243309802 - プレローディド・プレストレスト補強土のプレストレス維持装置の開発 (その2)
篠田昌弘; 石村隆敏; 中村俊朗; 内村太郎; 龍岡文夫
Volume：55th, Number：B, 2000
J-Global ID：200902119686361445 - プレローディド・プレストレスト補強土のプレストレス維持装置の開発 (その1)
内村太郎; 龍岡文夫; 篠田昌弘; 石村隆敏; 中村俊朗
Volume：55th, Number：B, 2000
J-Global ID：200902148091277343 - Observation and Estimation of Long-term Performance of Preloaded and Prestressed Geosynthetic-Reinforced Soil Structure
Uchimura T.; Tatsuoka F.; Tateyama M.; Siddiquee M. S. A.
Geosynthetics Engineering Journal, Volume：15, First page：312, Last page：321, 2000
Vertical preloading and prestressing (PLPS) of geosynthetic-reinforced soil structure aims at substantially increasing its stiffness and decreasing the residual settlement. The first prototype PLPS reinforced soil pier was constructed for a railway in 1996, and has been open to service for more than three years. Long-term measurements for more than four years have been made. It has been proven that PLPS structures are very stable for a long-term of service.The rheological characteristics such as creep and relaxation, and the residual deformation under cyclic loading of the backfill soil and reinforcement are considered to be important factors affecting the long-term behaviour of PLPS structures. The development of theoretical models of those behaviours is essential for developing the relevant design procedure of PLPS structures. In this paper, one of three-component rheology models, named "New Isotach Model", is used to analyze the observed load-deformation behaviour of the PLPS pier during its preloading procedure.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.15.312
DOI ID：10.5030/jcigsjournal.15.312, ISSN：1344-6193, J-Global ID：200902100344534078, CiNii Articles ID：130003450696 - Observation and Estimation of Long-term Performance of Preloaded and Prestressed Geosynthetic-Reinforced Soil Structure
Volume：15, First page：312, Last page：321, 2000 - PRELOADED AND PRESTRESSED REINFORCED SOIL
TATSUOKA Fumio; UCHIMURA Taro; TATEYAMA Masaru
Volume：39, Number：1, First page：129, Last page：131, 15 Feb. 1999
English
ISSN：1341-7452, CiNii Articles ID：110003946196, CiNii Books ID：AN10496056 - Laboratory cyclic loading tests on preloaded prestressed reinforced soil structure models.
菊地達哉; 杉村佳寿; 篠田昌弘; 内村太郎; 龍岡文夫
地盤工学研究発表会発表講演集, Volume：34th, 1999
ISSN：1342-2863, J-Global ID：200902102136762817 - Shaking Table Tests on Small Size Models of Preloaded and Prestressed Reinforced Soil Bridge Pier.
内村太郎; 龍岡文夫; 杉村佳寿; 篠田昌弘; 菊地達哉
地盤工学研究発表会発表講演集, Volume：34th, 1999
ISSN：1342-2863, J-Global ID：200902103243358154 - 補強砂の中型一面せん断試験におけるせん断領域と発現強度の相関
内村太郎; QIU J-Y; 龍岡文夫
Volume：54th, Number：B, 1999
J-Global ID：200902106549046465 - プレローディド・プレストレスト補強土のプレストレス維持装置
篠田昌弘; 杉村佳寿; 菊池達哉; 龍岡文夫; 内村太郎
Volume：54th, Number：B, 1999
J-Global ID：200902109884142540 - Quasi-elastic deformation of granular materials for arbitrary stress paths.
石原雅規; 龍岡文夫; 内村太郎
地盤工学研究発表会発表講演集, Volume：34th, 1999
ISSN：1342-2863, J-Global ID：200902110931517882 - Effects of horizontal preloding on the seismic behavior of models of preloaded prestressed reinforced soil structure.
篠田昌弘; 杉村佳寿; 菊池達哉; 内村太郎; 龍岡文夫
地盤工学研究発表会発表講演集, Volume：34th, 1999
ISSN：1342-2863, J-Global ID：200902124929654598 - Effects of prestressing on the resonance frequency of reinforced soil structures.
杉村佳寿; 篠田昌弘; 菊地達哉; 龍岡文夫; 内村太郎
地盤工学研究発表会発表講演集, Volume：34th, 1999
ISSN：1342-2863, J-Global ID：200902136536330829 - Improvement of deformation characteristics of reinforced soil structures against traffic and seismic load by preloading and prestressing.
内村太郎; 龍岡文夫; 篠田昌弘; 舘山勝
地盤工学シンポジウム論文集, Volume：44th, 1999
J-Global ID：200902137016556928 - 補強材使用による締固め時の地盤内応力集中特性
りょ翰成; 龍岡文夫; 内村太郎; 吉村慶
Volume：54th, Number：B, 1999
J-Global ID：200902143891242791 - Properties of the cross-anisotropic hypo-quasi elastic model.
龍岡文夫; 石原雅規; 内村太郎
地盤工学研究発表会発表講演集, Volume：34th, 1999
ISSN：1342-2863, J-Global ID：200902151860548410 - Effects of Using Reinforcement on Compaction of Near-saturated Soft Clay.
ROH H; 龍岡文夫; 内村太郎; 吉村慶
地盤工学研究発表会発表講演集, Volume：34th, 1999
ISSN：1342-2863, J-Global ID：200902199810060487 - Long-term Performance of Preloaded and Prestressed Geosynthetic-Reinforced Soil Structure
Uchimura T.; Tatsuoka F.; Tateyama M.; Koga T.
Geosynthetics Engineering Journal, Volume：14, First page：155, Last page：164, 1999
Vertical preloading and prestressing (PLPS) of geosynthetic-reinforced soil structure aims at substantially increasing its stiffness. The first prototype PLPS reinforced soil pier for a railway was constructed in 1996, and has been opened to service for more than 2 years. Long-term measurements for more than 3 years have been made, and the behavior at train passing was measured just after opening to service and after 2 years of service. The measurement results are described.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.14.155
DOI ID：10.5030/jcigsjournal.14.155, ISSN：1344-6193, J-Global ID：200902191760389325, CiNii Articles ID：130003680874 - Long-term Performance of Preloaded and Prestressed Geosynthetic-Reinforced Soil Structure.
Volume：14, First page：155, Last page：164, 1999 - Performance of Preloaded-Prestressed Geogrid-Reinforced Soil Railway Bridge Pier
Tatsuoka Fumio; Uchimura Taro; Tateyama Masaru; Kojima Kenichi
土と基礎, Volume：46, Number：8, First page：13, Last page：15, 01 Aug. 1998
Japanese
ISSN：0041-3798, J-Global ID：200902198883905128, CiNii Articles ID：110003976419, CiNii Books ID：AN0014925X - Behavior of PL/PS reinforced earth pier.
瀧岡文夫; 内村太郎; 舘山勝
日本鉄道施設協会誌, Volume：36, Number：1, 1998
ISSN：0913-2643, J-Global ID：200902111661320646 - Examination of elastic modulus of full scale model of PLPS reinforced soil by elastic wave velocity test.
杉村佳寿; 石原雅規; 内村太郎; 龍岡文夫; 舘山勝; 木村英樹
土木学会年次学術講演会講演概要集 第3部, Volume：53rd, Number：B, 1998
J-Global ID：200902125761603336 - Creep and cyclic loading test of full scale model of preloaded prestressed (PL PS) reinforced soil.
内村太郎; 龍岡文夫; 杉村佳寿; 石原雅規; 舘山勝; 木村英樹
土木学会年次学術講演会講演概要集 第3部, Volume：53rd, Number：B, 1998
J-Global ID：200902131072805860 - Effects of preloading and prestressing on deformations of geogrid reinforced sand under cyclic triaxial loading.
丸山直樹; 篠田昌弘; 内村太郎; 龍岡文夫
地盤工学研究発表会発表講演集, Volume：33rd, Number：2-2, 1998
ISSN：1342-2863, J-Global ID：200902131981060040 - Elastic stiffness of a full scale PL/PS reinforced soil model.
石原雅規; 杉村佳寿; 内村太郎; 龍岡文夫; 舘山勝; 木村英樹
地盤工学研究発表会発表講演集, Volume：33rd, Number：2-2, 1998
ISSN：1342-2863, J-Global ID：200902141508323233 - Effect of tie rod rigidity in preloaded prestressed reinforced earth method.
丸山直樹; 篠田昌弘; 内村太郎; 龍岡文夫
土木学会年次学術講演会講演概要集 第3部, Volume：53rd, Number：B, 1998
J-Global ID：200902160209208546 - Cyclic preloading on a full-scale model of PLPS reinforced soil embankment.
杉村佳寿; 石原雅規; 内村太郎; 龍岡文夫; 舘山勝; 木村英樹
地盤工学研究発表会発表講演集, Volume：33rd, Number：2-2, 1998
ISSN：1342-2863, J-Global ID：200902161022515590 - Effect of stress state in curing on deformation and strength characteristics of short material age cement improvement sand.
龍岡文夫; BARBOSA-CRUZ E R; 周郷啓一; 内村太郎
土木学会年次学術講演会講演概要集 第3部, Volume：53rd, Number：B, 1998
J-Global ID：200902169139996263 - Preloading on full-scale models of PLPS reinforced soil embankment.
内村太郎; 龍岡文夫; 杉村佳寿; 石原雅規; 舘山勝; 木村英樹
地盤工学研究発表会発表講演集, Volume：33rd, Number：2-2, 1998
ISSN：1342-2863, J-Global ID：200902172496357601 - Importance of prestress in preloaded prestressed reinforced soil.
篠田昌弘; 丸山直樹; 内村太郎; 龍岡文夫
土木学会年次学術講演会講演概要集 第3部, Volume：53rd, Number：B, 1998
J-Global ID：200902173215011643 - Laboratory cyclic loading tests on models of preloaded prestressed reinforced soil structure.
篠田昌弘; 丸山直樹; 龍岡文夫; 内村太郎
地盤工学研究発表会発表講演集, Volume：33rd, Number：2-2, 1998
ISSN：1342-2863, J-Global ID：200902184776022239 - Behavior of a Prototype Preloaded and Prestressed Reinforced Soil Bridge Pier in Service.
古賀徹志; 内村太郎; 龍岡文夫; 杉村佳寿; 石原雅規; 舘山勝; 小島謙一
地盤工学研究発表会発表講演集, Volume：33rd, Number：2-2, 1998
ISSN：1342-2863, J-Global ID：200902187284845956 - Local stress path in plane strain compression test of reinforcing sand by FEM analysis.
ほう芳楽; 小竹望; 龍岡文夫; 内村太郎
土木学会年次学術講演会講演概要集 第3部, Volume：53rd, Number：B, 1998
J-Global ID：200902195086148193 - Full-scale Behaviour of Prototype Preloaded and Prestressed Geosynthetic Reinforced Soil Structure and Some Proposals to its Design and Construction Method
Uchimura T.; Tatsuoka F.; Koseki J.; Tateyama M.; Koga T.
Geosynthetics Engineering Journal, Volume：13, First page：75, Last page：84, 1998
The preloaded and prestressed (PLPS) reinforced soil method aims at substantially increasing the stiffness of a geosynthetic-reinforced soil embankment by vertical preloading and prestressing. The first prototype PLPS reinforced soil pier for a railway was constructed, and preloaded and prestressed, which has been opened to service for more than 1 year. Long-term measurements for more than 2 years are described. The PLPS pier showed very small amount of instantaneous and creep compression by dead load and live train load. In addition, some new design and construction methods are proposed which can keep high stiffness for a long time and can improve its constructibility.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.13.75
DOI ID：10.5030/jcigsjournal.13.75, ISSN：1344-6193, CiNii Articles ID：130003680864 - Full-Scale Behavour of Prototype Preloaded and Prestressed Geosynthetic Reinforced Soil Structure and Some Proposals to its Design and Construction Method
Uchimura T.; Tatsuoka F.; Koseki J.; Tateyama M.; Koga T.
Geosynthetics Engineering Journal, Volume：13, First page：75, Last page：84, 1998
The preloaded and prestressed (PLPS) reinforced soil method aims at substantially increasing the stiffness of a geosynthetic-reinforced soil embankment by vertical preloading and prestressing. The first prototype PLPS reinforced soil pier for a railway was constructed, and preloaded and prestressed, which has been opened to service for more than 1 year. Long-term measurements for more than 2 years are described. The PLPS pier showed very small amount of instantaneous and creep compression by dead load and live train load. In addition, some new design and construction methods are proposed which can keep high stiffness for a long time and can improve its constructibility.
Japan Chapter of International Geosynthetics Society
DOI：https://doi.org/10.5030/jcigsjournal.13.75
DOI ID：10.5030/jcigsjournal.13.75, ISSN：1344-6193, J-Global ID：200902165951503763, CiNii Articles ID：130003680864 - Prototype Bridge Pier and Loading Tests on a Full-scale Model of Preloaded and Prestressed Reinforced Soil Embankment
内村太郎; 龍岡文夫; 古関潤一; 佐藤剛司; 小高猛司; 舘山勝
生産研究, Volume：49, Number：7, First page：334, Last page：337, Jul. 1997
Japanese
ISSN：0037-105x, J-Global ID：200902185168272628, CiNii Articles ID：120005222740, CiNii Books ID：AN00127075 - Triaxial repeated compression test on reinforced sand.
篠田昌弘; 内村太郎; 龍岡文夫
土木学会年次学術講演会講演概要集 第3部, Volume：52nd, Number：B, 1997
J-Global ID：200902138260010763 - Subsidence and deformation of preloaded prestressed reinforced embankment by repeated load.
内村太郎; 龍岡文夫; 丸山大介; 中村宏之
土木学会年次学術講演会講演概要集 第3部, Volume：52nd, Number：B, 1997
J-Global ID：200902177398692356 - Effects of Prestress in Preloaded and Prestressed Reinforced Soil Method.
龍岡文夫; 内村太郎; 志田芳樹; 柳沢秀樹
地盤工学研究発表会発表講演集, Volume：32nd, Number：2-2, 1997
ISSN：1342-2863, J-Global ID：200902132868123937 - Cyclic Loading Test on a Full Scale Model of Preloaded and Prestressed Reinforced Soil Embankment.
丸山大介; 龍岡文夫; 内村太郎; 中村宏之; 館山勝
地盤工学研究発表会発表講演集, Volume：32nd, Number：2-2, 1997
ISSN：1342-2863, J-Global ID：200902153790444925 - Construction of a Prototype Preloaded and Prestressed Reinforced Soil Bridge Pier.
内村太郎; 龍岡文夫; 中村宏之; 丸山大介; 館山勝; 古賀徹志
地盤工学研究発表会発表講演集, Volume：32nd, Number：2-2, 1997
ISSN：1342-2863, J-Global ID：200902166223923868 - Geosynthetic-reinforced soil retaining walls as important permanent structures - 1996-1997 Mercer Lecture
F Tatsuoka; M Tateyama; T Uchimura; J Koseki
GEOSYNTHETICS INTERNATIONAL, Volume：4, Number：2, First page：81, Last page：136, 1997
During the past decade, more than 26 km of geosynthetic-reinforced soil retaining walls (GRS-RWs) with full-height rigid (FHR) facings were constructed in Japan as important permanent structures mainly for railways and occasionally for highways. These include retaining walls for embankments, bridge abutments, a wall backfilled with a nearly saturated clay constructed on a thick soft clay deposit, a wall that survived a very severe earthquake, and walls constructed to support bullet train tracks. The full-height rigid facings are cast in place using staged construction procedures. A new method of stiffening reinforced soil by vertical preloading and prestressing is also described.
INDUSTRIAL FABRICS ASSOC INT, English
ISSN：1072-6349, Web of Science ID：WOS:A1997YK00800002 - Preloaded and prestressed reinforced Soil(共著)
FUMIO TATSUOKA; TARO UCHIMURA; MASARU TATEYAMA
Soils and Foundations, Volume：37, Number：3, First page：79, Last page：94, 1997
DOI：https://doi.org/10.3208/sandf.37.3_79
DOI ID：10.3208/sandf.37.3_79, ISSN：1341-7452 - Loading Tests and Long-Term Behaviour of Full-Scale PL・PS Reinforced Soil Models
Uchimura Taro; Tatsuoka Fumio; Muramoto Katsumi; Tateyama Masaru; Gu Xuedong; Koseki Junichi
Monthly journal of the Institute of Industrial Science, University of Tokyo, Volume：48, Number：3, First page：193, Last page：196, Mar. 1996
The University of Tokyo, Japanese
ISSN：0037-105X, J-Global ID：200902126365544277, CiNii Articles ID：110000243420, CiNii Books ID：AN00127075 - Behavior of full scale reinforced embankment model in PL PS loading test.
内村太郎; 龍岡文夫; 舘山勝
土木学会年次学術講演会講演概要集 第3部, Volume：51st, Number：B, 1996
J-Global ID：200902190922073223 - Investigation on application of PL/PS reinforced soil method to cohesive soil.
村本勝巳; 柴田博之; 内村太郎; 龍岡文夫
地盤工学研究発表会発表講演集, Volume：31st, Number：2-2, 1996
ISSN：1342-2863, J-Global ID：200902108152500774 - Mechanisms of PL PS reinforced soil and rheological properties of gravel.
龍岡文夫; 内村太郎; 本広竜三
地盤工学研究発表会発表講演集, Volume：31st, Number：2-2, 1996
ISSN：1342-2863, J-Global ID：200902112466091981 - Recent geosynthetic reinforced earth method. Characteristics, history, and future view of geosyntheetic reinforced earth retaining wall method.
龍岡文夫; 内村太郎; 古関潤一; 舘山勝
基礎工, Volume：24, Number：12, 1996
ISSN：0285-5356, J-Global ID：200902133985600106 - Fundamental Properties of Preloaded/Prestressed Geosynthetic-Reinforced Soil Retaining Will.
村本勝巳; 舘山勝; 内村太郎; 龍岡文夫
鉄道総研報告, Volume：10, Number：12, 1996
ISSN：0914-2290, J-Global ID：200902102951757429 - Changes in the prestress in full-scale PL PS reinforced soil models.
内村太郎; 龍岡文夫; 舘山勝; 本広竜三
地盤工学研究発表会発表講演集, Volume：31st, Number：2-2, First page：2413, Last page：2414, 1996
ISSN：1342-2863, J-Global ID：200902190782389519, CiNii Articles ID：10006091053, CiNii Books ID：AN10508847 - Mechanisms, Element Tests, Full-scal Model Tests and Construction of Preloaded and Prestressed Geosynthetic Reinforced Soil Structure.
内村太郎; 龍岡文夫; 舘山勝; 古関潤一; 前田崇; 鶴英樹
ジオシンセティックス論文集, Volume：11th, First page：72, Last page：81, 1996
ISSN：1344-6193, J-Global ID：200902199761093960 - A Full-scale Model Test of Preloaded and Prestressed Reinforced Soil Retaining Walls
Uchimura Taro; Tatsuoka Fumio; Koseki Junichi; Satou Takeshi; Kodaka Takeshi; Tateyama Masaru
Monthly journal of the Institute of Industrial Science, University of Tokyo, Volume：47, Number：9, First page：432, Last page：435, Sep. 1995
The University of Tokyo, Japanese
ISSN：0037-105X, J-Global ID：200902166877950775, CiNii Articles ID：110000243347, CiNii Books ID：AN00127075 - Working Principles of Preloaded and Prestressed Retzining Walls and Their Full-Scale Model Test Program
Uchimura Masaru; Tatsuoka Fumio; Sato Takeshi; Tateyama Masaru
Monthly journal of the Institute of Industrial Science, University of Tokyo, Volume：47, Number：8, First page：392, Last page：395, Aug. 1995
The University of Tokyo, Japanese
ISSN：0037-105X, J-Global ID：200902113977792623, CiNii Articles ID：110000243339, CiNii Books ID：AN00127075 - Working principles of Pre-stressed Reinforced Soil Retaining Walls and their full-scale test program.
内村太郎; 龍岡文夫; 舘山勝
土質工学研究発表会発表講演集, Volume：30th, Number：3-3, 1995
ISSN：0285-7340, J-Global ID：200902187863123466
- ゼロから学ぶ土木の基本 地盤工学
内村太郎 (単著)
オーム社, 2013
Total pages：228
ISBN：4274213374 - Proceedings of the International Workshop on ICT in Geo-Engineering
Miyata, Y., Okayasu, T., Furuya, H., Uchimura, T. and Otani, J.
Research Publishing Services, Sep. 2012 - Validation and interpretation of monitored behavior of slopes vulnerable to failure, Landslide Science and Practice, Vol. 2, C.
Uchimura, T., Towhata, I., Wang, L., and Qiao J.-P., (edited by Margottini et al.)
Springer-Verlag Berlin Heidelbelg, 2012 - アーバンストックの持続再生 第１３章：廃棄物を活用する：リサイクル・最終処分跡地の利用
2007 - 『アーバンストックの持続再生』 第13章 廃棄物を活用する：リサイクル・最終処分跡地の利用
内村太郎, (藤野陽三・野口貴文編著)
技法堂出版, 2007 - 『地盤補強技術の新しい適用 - 他工法との併用技術』 擁壁・盛土の補強における併用技術
内村太郎, 地盤工学会編
地盤工学会, 2006 - 『新しい補強土擁壁のすべて』 第8.1節 PL・PS補強土工法の適用
内村太郎, (龍岡文夫 監修)
総合土木研究所, 2005 - ジオシンセティックス入門(共著)
2001 - Performance of PLPS geosynthetic-reinforced soil structure against working and seismic loads.
Proc. of the 15th International Conference on Soil Mechanics and Geotechnical Engineering, Istanbul., 2001 - 『ジオシンセティックス入門』 第2章 ジオシンセティックスの種類、特徴、機能
龍岡文夫・内村太郎 ほか(共著) 国際ジオシンセティックス学会日本支部編
理工図書, 2001 - Long-term Behaviour of PLPS GRS Bridge Pier.
Proc. of Second European Geosynthetics Conference, Bologna, 2000 - Behavior of the first prototype and full-scale models of PLPS geosynthetic-reinforced soil structrure
Geosynthetics in Foundation Reinforcement and Erosion Control Systems, Proceedings of Geo-Congress'98, Boston, ASCE(American Society of Civil Engineers), 1998 - Preloaded-Prestressed Geogrid-reinfovced Soil Bridge Pier
Proceedings of the 6th Interanational Conference on Geosynthetics, Altanta, International Geosynthetics Society, 1998 - Performance of preloaded and prestressed geosynthetic-reinforced soil
Earth Rein forcement, Proceedings of International Symposium on Earth Reinforcement, Balkema,, 1996
- Evaluation of Soil Water Characteristics Curve Estimation and Prediction Techniques
Waqar, A., Uchimura, T., Umar, M.
Proceedings of the 16th International conference on geotechnical Engineering, Oct. 2023, [Domestic conference] - Effect of the optimum and residual moisture content on the strength characteristics of unsaturated sands
Waqar, A., Uchimura, T., Umar, M.
Proceedings of the 8th International Conference on Unsaturated Soils, May 2023, [Domestic conference] - 軽量粒状体(EPS)を加えたセメント改良土の締固め特性
市村和輝・内村太郎
Jul. 2022, [Domestic conference] - Evaluation of Soil Water Characteristics Curve Estimation and Prediction Techniques
Waqar Ahmad, Uchimura Taro and Muhammad Umar
Apr. 2022, [Domestic conference] - Effect of moisture content on particle breakage of recycled concrete aggregates during compaction
Shah S.K.H., Uchimura T. and Kawamoto K
Proceedings of 1st International Symposium on Construction Resources for Environmentally Sustainable Technologies (CREST) 2020, Fukuoka Japan., Advances in Sustainable Construction and Resource Management, Apr. 2021, [Domestic conference] - 顆粒状軽量気泡コンクリートを混合した再生路盤材の保水性評価
伊藤良平・加藤 晃・松野晃大・内村太郎・川本 健
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - Effect of degree of saturation on cyclic behavior of recycled concrete aggregates
Syed Kamran Hussain Shah, Taro Uchimura, Ken Kawamoto
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - 液状化地盤の側方流動にともなう全応力の変化
磯岡 一・Betzy Nella Redinoviria・内村太郎
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - 着色水と画像解析を使った地盤模型内の含水量分布の測定
戸田 樹・唐 俊峰・内村太郎
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - 降雨による斜面崩壊を模した一面せん断試験への速度逆数法の適用
市村祐哉・内村太郎・福原誠
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - Experimental investigation on effects of capillary barrier on slope stability under rainfall unsaturated soil slope stability capillary barrier
Tang Junfeng, Tao Shangning, Taro Uchimura, Makoto Fukuhara
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - Factors affecting elastic wave velocities in rainfall-induced shallow slope failure
Shangning Tao, Taro Uchimura, Makoto Fukuhara, Junfeng Tang
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - 挟在する礫層のキャピラリバリアが降水時の変形に及ぼす影響
福原誠・内村太郎・Tao Shangning・Tang Junfeng
第55回地盤工学研究発表会発表講演集, Jul. 2020, [Domestic conference] - Effects of soil moisture and shear deformation on elastic wave velocities in shallow slope
Shangning Tao, Taro Uchimura, Makoto Fukuhara, Junfeng Tang
Proc. of The 8th China-Japan Geotechnical Symposium, Mar. 2020, [International conference] - 斜面表層の傾斜の経時データに基づく表層すべりの発生予測
謝済仁・内村太郎
第15回地盤工学会関東支部発表会 Geo関東 講演集, Nov. 2018, [Domestic conference] - 多重せん断土槽で再現した斜面表層崩壊の予兆変形の進み方
福原 誠・内村太郎・陶 尚寧・高橋良輔
第15回地盤工学会関東支部発表会 Geo関東 講演集, Nov. 2018, [Domestic conference] - The Effect of Underground Short Piles with High Rigidity on Shear Stress and Displacement along Ground Failure Surface
Yuto Otani, Taro Uchimura
Proceedings of the 1st International Conference on Press-in Engineering 2018, Sep. 2018, [Domestic conference] - An Investigation Of Effect Of Distance And Shape Of Pile On The Displacement Of Gas Pipe By 3d Fe Analysis
Kohei Nagai, Naoki Suzuki, Yukihiro Ishihara and Taro Uchimura
Proceedings of the 1st International Conference on Press-in Engineering 2018, Sep. 2018, [International conference] - 地盤内に埋めた杭等の高剛性部材が地盤変位とせん断抵抗力に与える影響
大谷祐斗・内村太郎
第53回地盤工学研究発表会発表講演集, Jul. 2018, [Domestic conference] - 液状化砂が細い下水管内を流れる現象の再現実験
辻田佳歩・内村太郎
第53回地盤工学研究発表会発表講演集, Jul. 2018, [Domestic conference] - Changes of elastic wave velocity and attenuation in slope deformation
陶尚寧・内村太郎
第53回地盤工学研究発表会発表講演集, Jul. 2018, [Domestic conference] - 変状が見られる斜面への小型孔内傾斜センサーの設置及び観測事例
福原誠・王林・西江俊作・内村太郎・山口弘志・藤谷久
第53回地盤工学研究発表会発表講演集, Jul. 2018, [Domestic conference] - 斜面のすべり面の形状と表層で観測される傾斜・変位の関係
内村太郎・今野朗・Xie Jiren
第53回地盤工学研究発表会発表講演集, Jul. 2018, [Domestic conference] - 多重せん断土槽を用いた斜面表層崩壊の予兆現象に関する研究
神保慧・福原誠・内村太郎
第53回地盤工学研究発表会発表講演集, Jul. 2018, [Domestic conference] - 2016年熊本地震の被災斜面における傾斜と土壌水分の長期多点観測事例
王林・西江俊作・内村太郎
第53回地盤工学研究発表会発表講演集, Jul. 2018, [Domestic conference] - 熊本地震により損傷を受けた自然斜面における亀裂の拡大－阿蘇市的石地区の事例－
笹原克夫・内村太郎・平岡伸隆・土佐信一・大類光平・板山達至・王林・西條敦志
平成30年度砂防学会研究発表会講演集, May 2018, [Domestic conference] - 熊本地震により損傷を受けた自然斜面における降雨時の変形挙動の計測
土佐信一・笹原克夫・内村太郎・平岡伸隆・板山達至・王 林・西條敦志・大類光平
平成30年度砂防学会研究発表会講演集, May 2018, [Domestic conference] - Use of tilt sensors for monitoring of unstable slope with low cost sensor network
T. Uhimura
Proc. of the 6th International Symposium on Advances in Civil and Environmental Engineering Practices for Sustainable Development, Apr. 2018, [International conference] - Features of elastic wave propagation in soil with different exciter energy
Shangning Tao, Taro Uchimura, Junfeng Tang, Jiren Xie, Yulong Chen, Dong Huang
Proc. of The 7th China-Japan Geotechnical Symposium, Mar. 2018, [International conference] - A new method to Evaluate the initiation of landslide using tilt measurements
Xie Jiren, Taro Uchimura
The 7th China-Japan Geotechnical Symposium, Mar. 2018, [International conference] - Gas transport parameters and thermal properties of construction demolition waste and recycled materials under air-dried condition
Mohd Redzuan, B.M.S., A. Matsuno, T. Saito, T. Uchimura, S. Asamoto, and K. Kawamoto
第14回地盤工学会関東支部発表会 (Geo Kanto 2017), Nov. 2017, [Domestic conference] - Proposed early warning system of slope failure by monitoring inclination changes in multi-point tilt sensors
Lin Wang, Shunsaku Nishie, Ling Su, Taro Uchimura, Shangning Tao, Ikuo Towhata
Proc. of the 19th International Conference on Soil Mechanics and Geotechnical Engineering, Sep. 2017, [International conference] - 仮説時に使用可能な地山補強と計測に関する実大規模崩壊実験
平岡伸隆・吉川直孝・副田尚輝・伊藤和也・笹原克夫・内村太郎・芳賀博文・王林・土佐信一・板山達至
土木学会第72回年次学術講演会講演概要集, Sep. 2017, [Domestic conference] - Numerical study about rainfall infiltration of 2013 Izu-Oshima slope failure
Takaki Matsumaru, Satoru Hagino, Taro Uchimura
Proc. of The 19th International Conference on Soil Mechanics and Geotechnical Engineering, Sep. 2017, [International conference] - 熊本地震で多数の亀裂が生じた斜面における傾斜変動
笹原克夫・内村太郎・平岡伸隆・大類光平・板山達至・WANG Lin・西條敦志
地すべり学会研究発表会 長野大会, Aug. 2017, [Domestic conference] - 一面せん断模型実験を用いた斜面の表層変位による崩壊予測方法の検討
大原勇・Kapila Ranjith Withanage・内村太郎
第52回地盤工学研究発表会発表講演集, Jul. 2017, [Domestic conference] - 多点計測による2016年熊本地震の被災斜面における傾斜及び土壌水分変化の長期観測
王林・蘇綾・西江俊作・内村太郎・陶尚寧
第52回地盤工学研究発表会発表講演集, Jul. 2017, [Domestic conference] - 弾性波探査屈折法を応用した斜面崩壊予兆の検知
陶尚寧・Selvarajah Hemakanth・内村太郎
第52回地盤工学研究発表会発表講演集, Jul. 2017, [Domestic conference] - 不飽和多層地盤の層境界を通過する浸透流に関する実験的研究
岡部祐美・松丸貴樹・内村太郎
第52回地盤工学研究発表会発表講演集, Jul. 2017, [Domestic conference] - Distributed tilt sensors for an early warning monitoring of earthquake-induced landslide and slope failures
Wang, L., Nishie, S., Su, L., Uchimura, T., Tao, S., Dong Huang, D., Qiao, J.-P., Shi, L. and Zhong, H.
Proc. of The 3rd International Conference on Performance-based Design in Earthquake Geotechnical Engineering (PBD-III), Jul. 2017, [International conference] - An early warning system of unstable slopes by multi-point MEMS tilting sensors and water contents
Lin Wang, Shunsaku Nishie, Taro Uchimura, Ikuo Towhata, Ling Su, Shanging Tao
Proc. of the 4th World Landslide Forum, May 2017, [Domestic conference] - Explore on Hydro-Mechanical Threshold for Early Warning of Rainfall induced Landslides
Zongji YANG, Jianping Qiao, Taro Uchimura, Lin Wang, Dong Huang
Proc. of The 4th World Landslide Forum, May 2017, [International conference] - Development of tilt angle in surface layer of slope during pre-failure stages induced by rainfall
Jimbo, S., Hsieh, C., Xie, J., Chen, Y., Uchimura, T., Wang, L., and Su, L.
Proc. of the 7th Japan-Taiwan Workshop on Geotechnical Hazards from Large Earthquakes and Heavy Rainfall, Sep. 2016, [International conference] - Multi-point monitoring of unstable slope with tilt sensors
T. Uchimura, S.N. Tao, I. Towhata , L. Wang, L. Su, S. Nishie, H. Yamaguchi and I. Seko
Proc. of the International Conference on Smart Infrastructure and Construction, "Transforming the Future of Infrastructure through Smarter Information", Jun. 2016, [International conference] - Monitoring system by vibration power generation
Y. Yoshida, Y. Kobayashi and T. Uchimura
Proc. of the International Conference on Smart Infrastructure and Construction, "Transforming the Future of Infrastructure through Smarter Information", Jun. 2016, [International conference] - Stability monitoring of post-earthquake slope failure by using multi-point tilt sensors
L. Wang, S. Nishie, M. Fukuhara, T. Uchimura, K. Sasahara
Proc. of the 7th International Conference on Earthquake Geotechnical Engineering, [International conference]
- 鉄道システムを対象とした災害・事故の早期警報／危機管理システムの研究）
2003 - 2005 - 強震動に対する盛土・橋台部の耐震性向上に関する研究（土の動的挙動解明と耐震補強の理論的研究）
2000 - 2002
- Detecting precaution, prediction, and early warning for surface landslides
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2020 - 31 Mar. 2023
Saitama University
Grant amount(Total)：16770000, Direct funding：12900000, Indirect funding：3870000
Grant number：20H02239 - Detection of changes in water contents and precaution of failure of slope surface based on elastic wave propagation
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2016 - 31 Mar. 2019
Uchimura Taro, Saitama University
Grant amount(Total)：16380000, Direct funding：12600000, Indirect funding：3780000
In this study, a method to evaluate shear deformation and soil moisture of slopes by using elastic wave is presented. A full-scale multi-layer shear model was used to simulate the pre-failure process of a slope, and the wave propagation was observed. The detailed behavior of elastic wave propagation in soil over a wide range of soil moisture, shear stress, and shear deformation, were explored.
To investigate the behavior of elastic wave propagation in the natural slope surface layer, elastic wave monitoring has been conducted at a slope located at Aso City, Kumamoto, Japan. This slope was suffered from the 2016 Kumamoto Earthquakes and some big cracks appeared on the slope surface. Behaviors of elastic wave velocities and attenuation with soil moisture on-site are similar to laboratory experiments.
Grant number：16H04407 - Mechanisms of pipe flow of liquerfied sand its control
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, 01 Apr. 2015 - 31 Mar. 2018
UCHIMURA Taro
Grant amount(Total)：3770000, Direct funding：2900000, Indirect funding：870000
In the 2011 Great East Japan Earthquake, the sewage systems had serious damages that large amount of liquefied sand flowed into the pipes for long distances. Pipes with small diametes in house areas were considered as one of possible routes for the sand to flow into the pipe system. In this study, the flow of liquefied sand through a pipe with small diamter was simulated by model tests.
As a results, the liquefied sand did not flow so much after the cross section of the pipe was filled with sand. The total stress measured along the inner surface of the pipe showed significantly large values, which suggests clogging of the sand in the pipe. Therefore, it may be difficult for the liquefied sand with a large amount through pipes with small diameter.
In addition, the inner total stress showed high values and low vaules alternately with periods of several seconds. Such behaviour is never observed with ordinal flued like water, and is specific with the granular materials.
Grant number：15K14027 - Risk evaluation and early warning for slope disaster induced by earthquake and rainfall
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2013 - 31 Mar. 2017
UCHIMURA Taro; NISHIE Shunsaku; WANG Lin; QIAO Jian-Ping; YANG Zongji; HUANG Dong; HUANG An-Bing; LU Chin-Wei
Grant amount(Total)：15990000, Direct funding：12300000, Indirect funding：3690000
Slope disasters caused by heavy rainfall after strong earthquake are studied in cooperation among research groups from China, Taiwan, and Japan. Slopes in mountanious areas are often damaged with cracking and deformation by strong seimic events. Even in case they are not failed, they may be less durable against heavy rainfall than before the eathquake. To take care of such cases, following studies are conducted:
1) Mechanism of slope weakening due to strong earthquakes are discussed, and methods of risk evaluation are developed based on results from case studies, monitoring with sensors on site, and model/site experiments.
2) Low cost and simple monitoring and early warning equipments for slope failures are developed to reduce the risk of disasters. In addition, new methods as like multi-points monitoring and monitoring based on changes in elastic wave propagation through the surface layer are studied.
Grant number：25303015 - Mechanism and mitigation of slope disasters caused by combined effects of earthquake and rainfall
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), 01 Apr. 2012 - 31 Mar. 2016
Towhata Ikuo; Uchimura Taro; Yamada Suguru
Grant amount(Total)：45760000, Direct funding：35200000, Indirect funding：10560000
Human settlement is destroyed by debris flow and many casualties are claimed. Thus, it is important to study not only the shear strength reduced by weathering but also softening of stress-strain behavior after peak strength. In this regard, laboratory studies were performed, chemical weathering was reproduced and the decay of tested material were investigated on natural rocks as well as mixing sand, lime, gypsum and water at a specified ratio and cured for a certain time. Prepared specimens were submerged in acidic water with ph = 4 or 5 and the particle-to-particle bonding was destroyed chemically. Then, unconfined compression tests were run on samples with different extents of chemical weathering. Using the measured stress-strain relationship, study was made of the decay of the peak strength and the softening behavior that followed the peak. Moreover, point load tests were conducted to investigate more profoundly a number of weathered rock pieces.
Grant number：24246082 - Comprehensive study on slope disaster in Izu Oshima Island caused by Typhoon 26 in 2013
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Special Purposes, 2013 - 2014
TOWHATA Ikuo; HIROOKA Toshihiko; KAWANO Tetsuya; NAKADA Setsuya; MIYABUCHI Yasuo; MAENO Fukashi; MATSUSHI Yuki; TERAJIMA Tomomi; HATTANJI Tsuyoshi; UCHIMURA Taro; GOTO Satoshi; WAKAI Akihiko; OU Kouki; KOKUSHO Takaji; TAKEBAYASHI Hiroshi; IMAIZUMI Fumito; SHIMIZU Yoshihiko; TAMURA Keiko; USHIYAMA Motoyuki; DOI Issei; YAMADA Masumi, The University of Tokyo
Grant amount(Total)：21570000, Direct funding：21570000
A comprehensive study was made after the 2013 slope disaster in Izu Oshima induced by an extremely heavy rainfall event. The research team was composed of people from such disciplines as geology， hydrology， meteorology， geotechnical engineering and disaster mitigation science. Emphases were placed on the causative mechanism of the disaster on the basis of field studies， revealing the limitation of current disaster mitigation principles and future improvement for better safety. The damaged volcanic slope was made of interbedding of volcanic ash， lava and other materials and their different hydraulic conductivities affected the slope instability during heavy rain. The current early warning based on rainfall criterion does not consider the topography and geological/soil-mechanic issues and needs to be supplemented by more local monitoring of slope behavior. Further care is needed on evacuation practice because mid-night evacuation during heavy rain may claim additional victims.
Grant number：25900002 - コンクリート系床版に内在する凝縮水の動態による早期疲労限界状態
2011 - 2011
Grant amount(Total)：25350000, Direct funding：19500000, Indirect funding：5850000
Grant number：23246083 - Simplified protective structure against debris flow for safe transportation in mountainous region
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, 2010 - 2011
TOWHATA Ikuo; UCHIMURA Taro; YAMADA Suguru, The University of Tokyo
Grant amount(Total)：3580000, Direct funding：3100000, Indirect funding：480000
Damage investigations that were conducted after such significant earthquakes in mountainous regions as the Niigata-Chuetsu earthquake in 2004, the Kashmir earthquake in Pakistan, 2005, and the 2008 Wenchuan earthquake in China demonstrated that problems were caused not only by the strong shaking and related phenomenon but also the post-earthquake instability of mountain slopes that were affected by the shaking. The latter means that slope failures during the period of emergency rescue and re-construction, road transportation at the bottom of unstable slopes is vulnerable to slope failures and is often stopped in particular during rain falls. To protect such important emergency activities from the slope problems, some structural measure was considered necessary. It was thought important further that the planned structure does not have to be so safe as normal structures in sloping ground because the road transportation to be protected is not of the ordinary type but are the emergency vehicles whose safety demand is not very high under special situations. Hence, the present research intended to investigate a simple and portable tunnel structure that mitigates the effects of debris flow on road transportation. The central aim was the evaluation of the impact force between debris flow and a protective structure. Because a study on a real-scale structure undergoing debris flow is impossible, a small-scale model study was made. By changing the amount of debris, debris types, the length of a slope, its gradient, and friction of the slope surface, tests were repeated on the distribution of impact pressure, its time history, and bending moment in an affected structure. Accordingly, a regression analysis was made to obtain an empirical formula for those values. The concerned structures were a vertical retaining wall and a tunnel. In addition, an energy viewpoint was introduced to investigate in a more rational manner the mechanism of generation of significant impact force. Furthermore, a discrete element analysis was developed to numerically reproduce the impact phenomenon in a greater scale. These efforts were made to apply results from small-scale model tests to a greater proto type in the field.
Grant number：22656105 - Practical use of low-cost and simple monitoring system for slope failures due to heavy rainfall based on water contents and tilting angles
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (A), 2009 - 2011
UCHIMURA Taro, The University of Tokyo
Grant amount(Total)：24310000, Direct funding：18700000, Indirect funding：5610000
A practical, low-cost and simple monitoring and early warning system for slope disasters due to heavy rainfall was developed. It consists of volumetric water content sensors and tilt sensors connected to a sensor networks. The developed equipments were modified for its functions and reliability, and verified by pilot deployment into unstable slopes in Japan and China. Some criteria for issuing warning based on real time data from the tilt sensors were proposed by analyzing the results of field measurements. Some laboratory tests were conducted to investigate wave velocity as index of water contents and instability of slopes consisting of unsaturated soils. Laboratory tests were also conducted to theoretical modeling of hydraulic properties and deformation properties of slopes.
Grant number：21686043 - Laboratory reproduction of weathering and deterioration of soft-rock slopes and its application to disaster mitigation.
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), 2009 - 2011
TOWHATA Ikuo; UCHIMURA Taro; YAMADA Suguru, The University of Tokyo
Grant amount(Total)：40950000, Direct funding：31500000, Indirect funding：9450000
Physical weathering of rock material induces loss of rigidity and deterioration of strength. This process was first reproduced in a newly developed testing device in which water-submergence, freezing, and heating were repeated. This test was able to reproduce the said rigidity loss and strength deterioration. Second, field studies were made in slope instability areas in both Japan and Pakistan where slope disasters have been significant. By using the knowledge thus collected, a methodology was developed by which the temporal progress of weathering and deterioration is traced and the mitigation of slope disaster is initiated at a critical time when the instability is imminent.
Grant number：21246076 - 低コストなセンサーネットワークを用いた斜面地盤の水理特性(集水・排水)の評価
2008 - 2009
Grant amount(Total)：3500000, Direct funding：3500000
Grant number：20656077 - Development of simpleand low-cost early warning system for landslides due to heavy rainfall based on sensing water contents and tilting
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (A), 2007 - 2008
UCHIMURA Taro; TOWHATA Ikuo; YAMADA Suguru; WANG Lin; SEKO Ichiro, The University of Tokyo
Grant amount(Total)：14950000, Direct funding：11500000, Indirect funding：3450000
Grant number：19686031 - 音響伝播特性を用いた斜面地震の水分量センサーの開発
2006 - 2007
Grant amount(Total)：3400000, Direct funding：3400000
Grant number：18656132 - Zero gravity tests on deformation characteristics of sand under low effective stress
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 2006 - 2007
TOHATA Ikuo; UCHIMURA Taro, The University of Tokyo
Grant amount(Total)：17090000, Direct funding：15500000, Indirect funding：1590000
In the recent times, much effort has been made to introduce into practice the principle of performance-based design, and geotechnical earthquake engineering is not an exception. The present study concerns evaluation of liquefaction mitigation technologies by which residual deformation of ground is reduced. This is particularly the case of mitigation technologies for a river dike, harbor quay wall, and buried pipelines. The investigators have been doing efforts to develop a deformation model for liquefied sand m which effective stress is extremely low Encountered problems are, for example, that laboratory shear tests with extremely low effective stress resulted in self-weight collapse of sand specimens and the stress nonuniformity due to self weight of sand particles. On the other band, shaking model tests could not precisely reveal stress-strain states of sand, although the state of full liquefaction was easily developed. To overcome these problems, the present study conducted shear tests under zero-gravity environment. A triaxial shear device was specially designed and fabricated so that it would suit a zero-gravity testing facility which made use of a deep vertical shaft Special machine control was needed for satisfactory tests because the duration time of zero gravity was merely a few second during flee fall of the shear device.
There were three difficulties in running experiments. First; controlling the operation in line with the commencement of free wall required care. Second, development of a small loader for triaxial compression test needed efforts. The size had to be small to be cased in a limited size of a free-fall capsule. The most difficult problem was the removal of effective stress developed by positive dilatancy of water-saturated sand during fine fall. This last problem was overcome finally by employing dry specimens for which drained shear was conducted. Tests showed that strain increased at a constant rate under constant stress, implying viscous nature of sand. The friction angle under the extremely low stress was nearly 70 degrees. Consequently the viscosity coefficient was about 400 kPaSec. This data was employed in assessment of the mitigative performance of measures for river dike such as underground sheet piles and berms.
Grant number：18360226 - Long-term performance assessment platform of interacted soil-structure system based on multi-scale analysis
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (S), 2003 - 2007
KOICH Maekawa; TOHATA Ikuo; ISHIDA Tetsuya; UCHIMURA Taro; MAKI Takeshi; NAKARAI Kenichiro, The University of Tokyo
Grant amount(Total)：110370000, Direct funding：84900000, Indirect funding：25470000
(1) Mass transfer, energy conservation, transient process of reaction and kinematic deformation are integrated by composing the linked micro-pores of soil foundation with cement hydrates, and the simulation platform for life-span evaluation of soil and structures was developed. This system was further extended to the liquefied soil-structure interaction by considering the pore water pressure and deformation of soil particle assembly in motion.
(2)Temperature dependency of water retainability of concrete and soils was investigated, and the enhanced transient moisture equilibrium modeling of pore water was built with high accuracy. The rapid release of trapped water by large-scale pores at higher temperature was explored and past theorem was revised. At the same time, leaching of calcium from hardened hydrate and its adsorption by natural soil foundation was simulated with regard to the transient states of thermodynamic equilibrium.
(3)Macroscopic time-dependent constitutive modeling was formulated based upon the kinematics of CSH gel and capillary water, and the time-dependent creep and shrinkage was investigated with molecular dynamics.
(4)The injection of corroded gel into the concrete progressive cracks was solved with the crack development. This enables us to assess the performance life of cover concrete under various ambient conditions.
(5)Great nonlinear interaction of group piles and soil was experimentally re-produced under rapid liquefaction excited by the dynamic shaking table and the micro and macro responses were captured. The soil particle constitutive modeling coupled with the multi-directional crack laws of reinforced concrete was verified as powerful tool of overall simulation with reasonable accuracy.
(7) The effect of time-dependency on high cycle fatigue was experimentally extracted and the versatile fatigue simulation model of structural concrete was formulated, and successfully installed to the direct path-integral scheme of simulating the whole structural system with micro-scale events for a long-term performance.
Grant number：15106008 - 中等科学教育におけるオーダーメードカリキュラムの開発および形成的評価法の研究
2005 - 2006
Grant amount(Total)：8300000, Direct funding：8300000
Grant number：17011050 - 杭・矢板構造物と地盤、地中構造物の相互作用
2006
Competitive research funding - Seismic reinforcing of existing soil structures and advanced application of soil reinforcing technology to construction of highly aseismic environment-friendly soil structures
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (S), 2001 - 2005
TATSUOKA Fumio; TOWHATA Ikuo; KOSEKI Junichi; UCHIMURA Taro; TANAKA Tadatsugu; TSUKAMOTO Yoshimichi
Grant amount(Total)：101660000, Direct funding：78200000, Indirect funding：23460000
The strength and deformation characteristics of geosynthetic reinforcement when subjected to sustained and cyclic loading were evaluated by performing a comprehensive series of tensile loading tests. By analyzing results from tests lasting for up to 30 days, a constitutive model that can fully explain the test results was developed. The residual deformation characteristics of backfill, which is another constituting material of geosynthetic-reinforced soil structure, were evaluated by performing sustained and cyclic loading triaxial tests on a variety of backfill material. The test results were analysed to obtain empirical equations that are to be incorporated into numerical analysis. Moreover, model loading tests on geosynthetic-reinforced soil structures, including retaining walls, and level grounds were performed under plane strain conditions to validate the numerical analysis method. In particular, the effects of sustained and cyclic loading on the deformation of geosynthetic-reinforced soil structure were studied evaluating the possibility of creep rupture failure of geosynthetic reinforcement and the effects of preloading and prestressing. A FEM code to simulate model behaviour as observed above was developed. Finally, the feasibility of the use of crushed concrete as the backfill of geosynthetic-reinforced soil structures allowing a limited amount of instantaneous and residual deformation was studied by performing consolidated drained triaxial compression tests on specimens having a wide range of density and at a wide range of confining pressure. In particular, triaxial compression tests on 30 cm-diameter and 60 cm-high specimen of a crushed concrete available in the field were performed. It was found that, when highly compacted, the strength and stiffness of crushed concrete becomes as high as the best backfill material (i.e., well-graded crushed hard rock). This trend did not change when increasing the confining pressure up to 600 kPa. The strength and stiffness of cement-mixed crushed concrete were also as good as cement-mixed well-graded crushed hard rock in drained triaxial compression.
Grant number：13852011 - 破砕タイヤ廃材の地盤構造物への適用
2005
Competitive research funding - Low cost and simple warning system for slope failure
2005
Competitive research funding - 中等科学教育におけるオーダーメードカリキュラムの開発および展開研究
2003 - 2004
Grant amount(Total)：7300000, Direct funding：7300000
Grant number：15020105 - 中等科学教育におけるポートフォリオを活用したオーダーメードカリキュラムの開発
2002 - 2002
Grant amount(Total)：3900000, Direct funding：3900000
Grant number：14022108 - 硬質地盤材料の変形特性の除荷過程での時間効果の観測とモデル化
2000 - 2001
Grant amount(Total)：2200000, Direct funding：2200000
Grant number：12875085 - プレローディド・プレストレストによる補強土のクリープ圧縮・繰返し載荷時の残留圧縮の抑制
1999 - 2000
Grant amount(Total)：2100000, Direct funding：2100000
Grant number：11750436 - 地盤材料の変形特性に対する時間効果の新しい展開
1999 - 2000
Grant amount(Total)：8200000, Direct funding：8200000
Grant number：11450180 - 地盤材料におけるセメンテイション発達過程に対する拘束応力条件の影響
1998 - 1999
Grant amount(Total)：2100000, Direct funding：2100000
Grant number：10875094 - 破砕タイヤ廃材の地盤構造物への適用
Competitive research funding - 補強土、盛土構造物の長期変形性能
Competitive research funding - 市民防災を目指した簡便で安価な斜面の早期警報／危機管理システムの研究
Competitive research funding - 破砕コンクリート廃材の高級盛土材への適用性の研究
Competitive research funding - 良質盛土材量をさらにセメント改良することによる高級盛土材の開発
Competitive research funding - 地盤材料の変形特性に対する長期・くりかえし載荷の影響
Competitive research funding - プレロードとプレストレスによって補強盛土の剛性を高める研究
Competitive research funding - Crushed waste concrete as a high quality backfill materials
Competitive research funding - High quality backfill materials by cement-treatment to well graded gravels
Competitive research funding - Effects of Creep and Cyclic Loading on Deformation Characteristics of Geomaterials
Competitive research funding - Study on a new method to stiffen a reinforced soil embankment by preloading and prestressing
Competitive research funding