2000 Fiscal Year Final Research Report Summary
Study on landslide mechanism and mechanical property of clay due to large deformation
| Project/Area Number |
11650502
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Geotechnical engineering
|
|---|
| Research Institution | Nagaoka University of Technology |
|---|
Principal Investigator |
OHTSUKA Satoru Nagaoka University of Technology, 工学部, 助教授 (40194203)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
DOI Masanobu Takamatsu National College of Technology, 助教授 (10110131)
|
|---|
| Project Period (FY) |
1999 – 2000
|
| Keywords | Landslide / Shear strength / Triaxial testing / Pore water pressure / Clay |
|---|
| Research Abstract |
Pore water pressure loading test on clay under constant deviator stress has been conducted to investigate the behavior of landslide. From the observation on soil specimen, two thresholds in pore water pressure for deformation were obtained. One was a yield point defined from the discrepancy from the swelling line in the void ratio and mean effective stress space. The other was a failure point where the soil specimen deforms largely and the deviator stress could not keep constant. A series of tests resulted in the yield points locating on the critical state line. At the failure point the soil specimen already got heterogeneous and deformed progressively. The soil dilated with shear due to overconsolidation and deformed with water migration. It caused the soil deformed with time for a long time. It was thought a reason for the slow failure of landslide. Numerical simulation with the Hashiguchi model well presented the soil behavior of pore water pressure loading test. It predicted the soil, which was initially overconsolidated, would get to the normally consolidated state by the repeats of pore water pressure loading. The failure point line was obtained in the void ratio and mean effective stress space for pore water pressure loading. This failure point line was empirically examined, but the effect of causes on the failure point line was still left to future stubjects. The steady state of soil after the repeats of pore water pressure loading was investigated numerically. It was found to depend on the recovery in mean effective stress. When the recovery was large, the soil would stand for larger pore water pressure loading. From the viewpoint of strain level, the ring shear test was conducted on the soil to investigate the angle for shear resistance at the residual state. The angle for shear resistance got lower with large deformation and it inspired the landslide for gentle slope.
|
