2002 Fiscal Year Final Research Report Summary
Study on shear strength property of re-slide type landslide and failure mechanism
| Project/Area Number |
13650538
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Nagaoka University of Technology |
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Principal Investigator |
OHTSUKA Satoru Nagaoka University of Technology, Civil and Environment Engineering, Associate Professor, 工学部, 助教授 (40194203)
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| Co-Investigator(Kenkyū-buntansha) |
IWABE Tsukasa Yatsushiro National College of Technology, Civil and Architectural Engineering, Associate Professor, 助教授 (80213312)
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| Project Period (FY) |
2001 – 2002
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| Keywords | landslide / pore water pressure / repeated load / creep behavior |
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| Research Abstract |
Pore water pressure loading test on clay under constant deviator stress was conducted to investigate the behavior of landslide. From the observation on soil specimen, two threshold magnitudes in pore water pressure for deformation were obtained. One was a yield point and the other was a failure point. It was shown that the constitutive equation of sub-loading surface mode could express these threshold magnitudes through the comparison with experiments. The change in threshold magnitudes for repeats of pore water pressure loading was investigated with simulation. The failure envelopment line was drawn for failure points against the repeats of pore water pressure loading, which expressed the change process of state variable for repeated loads. The obtained failure envelopment line was examined with experiments. The existence of failure envelopment line was proved, however, the discrepancy between simulation and experiment was observed. It was pointed out to the progressive failure of soi
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l specimen in experiment. The lost of element property in specimen was a serious problem to investigate the ideal failure stress in experiment. The detailed discussion was left to future problem. Time dependent behavior of soil specimen for pore water pressure loading was observed due to progressive failure. It suggested that the slow failure of landslide was due to progressive failure from the viewpoint of soil mechanics. The so-called second creep behavior was also measured in experiment. This phenomenon would be clarified from soil-water coupling concept. In pore water pressure loading cycle, two opposite effects were observed: one was a strain softening for increase in pore water pressure and the other was a consolidation for decrease in pore water pressure. The balance of two opposite effects much affected the soil strength of clay for repeated loads. In this study stability method for slope including the preformed slip line was also developed. Rigid plastic constitutive equation was employed. Less
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