| Project/Area Number |
02650347
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
基礎・土質工学
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| Research Institution | Faculty of Science and Engineering, Saga University |
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Principal Investigator |
YOSHITAKE Shigeki Faculty of Science and Engineering, Saga University, Research Associate, 理工学部, 助手 (00145187)
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| Co-Investigator(Kenkyū-buntansha) |
ONITSUKA KAtsutada Faculty of Science and Engineering, Saga, University, Professor, 理工学部, 教授 (20037948)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1990: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Decomposed granite soil / Direct shear test / Low confining pressure / Strength parameter / Centrifuge model test / Slope failure / Slope stability analysis / 安定解析 / 遠心力載荷試験 / 低拘束圧域 |
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| Research Abstract |
In order to investigate the slope failure mechanism of decomposed granite soil, centrifuge model tests were conducted. Shallow sliding type of slope failures were observed. Moreover, in order to the shear characteristics of decomposed granite soil, direct shear tests and triaxial compression tests were carried out under low confining pressure and moderate pressure. Using strength parameters obtained from triaxial compression tests under both pressures, the safety factors of decomposed granite soil slopes were calculated by finite element method. The results summarized as follows :
1)For decomposed granite soil, some differences in the constants of shear strength(c, phi)were obtained between low confining pressure and moderate pressure. Particularly, the apparent cohesion under low confining pressure is less than that under moderate pressure. The degree of decrease in shear strength due to soaking is greater than in the region of low confining pressures than at moderate pressures. 2)Under low confining pressure, apparent cohesion peaks at small shear displacement and stays constant after that. The ratio of decrease in apparent cohesion at residual state to the maximum apparent cohesion is large under low confining pressure. 3)Sballow sliding type were observed from the slope failure tests of unsaturated decomposed granite soil and the slope failure tests of decomposed granite soil due to rainfall. 4)The values of shear strength under low confining pressure are important and necessary for the analysis of the slope stability. Using finite element method, the slope failure mechanism can be explained by slope stability analysis considering the variation of shear resistance under low pressure.
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