1991 Fiscal Year Final Research Report Summary
Stability of Earth Structure in Connection with Progressive Failure
| Project/Area Number |
02452198
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | Tokyo Denki University |
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Principal Investigator |
YAMAGUCHI H. Tokyo Denki Science and Professor University, Technology, 理工学部, 教授 (70016228)
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| Co-Investigator(Kenkyū-buntansha) |
KUSAKABE Osamu Hiroshima Engineering, Professor University., 工学部, 教授 (40092548)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Progressive Failure / Slope Stability / Centrifuge Loading Test / Strain Softening / Slip Line / Ring Shear Apparatus |
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| Research Abstract |
1. Undisturbed and disturbed sand were sheared using triaxial and plane strain compression. The progressive behavior of cohesion component due to strain level was observed. and it was guessed that the failure of natural ground starts first close to surface zone.
2. Ring shear apparatus has been installed. The stlear tests of dry Toyoura sarid and Kaoline clay were conducted by this apparatus. Remarkable progressive phenomenon could be seen that strain softening occurs continuously from peak point to residual state.
3. By the concept that the residual void ratio is unaqtie irrespective of the initial void ratio, the thickness of shear zone of Toyoura sand could be presumed.
The result that the shear zone is 20 times as thick as the mean size of sand grain conforms fairly well to the observed one by another investigator.
4. The measured displacements at peak point and residual state of Kaolin clay were 5- 6mm and 40- 50mm respectively according to tlie present expelment.
These magnitude should be taken into consideration when the failure of soil mass in small sized model test is interpreted from the view point of progressivity.
5. It was concluded that the number of tracking line should be iticreasd in order to analyse the film image in high accuracy.
6. The failure tests of the slopes of overconsolidated Kaoline clay were conducted using drum centrifuge. The displacement vector and maximum shear strain vactor obtained show that the progressive failure was clearly observed and in highly overconsolidated clay the slip line lies close to the surface atid brittle failure was likely to occur.
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