Zaidatul Azmi

Inverse Analysis for Stiffness Factor of Landslide and Its Application to Failure Prediction

Satoru OHTSUKA

Due to the rainfall and melted snow, the groundwater level rise and this is one of the main reasons why the landslides occur. As a model of the rise of the groundwater level, the pore water pressure loading test has been carried out. The pore water pressure loading test is a test where the pressure is loaded from the bottom of the specimen using the triaxial compression test apparatus. From the test results, the failure behaviour of the specimen has been observed.

From the observation, these can be concluded.

1.Due to the loading on a cohesive clay specimen, from initial point to yield point, the specimen shows an elastic ehaviour by moving along the swelling line. But after the plastic deformation, it splits from the swelling line and expended until it fails.
2.As the value of the over consolidated ratio bigger, the time of the experiment also longer. This is because when the specimen is over consolidated, the water could not migrate smoothly.
3.Under the same test condition, the failure time also tends to be longer as the value of the over consolidated ratio bigger. This is because due to the difference in failure formation of the specimen, the degree of progressive failure also differs.
4.From the relationship of tangent modulus and secant modulus between strain and pore water pressure, the failure of landslides could be predicted. Both relations show the same behaviour, which is decreasing with the plastic deformation from yield point and failed.
5.The stiffness factor is defined as the ratio between strain and pore water pressure regarding the effective stress. When the stiffness factor is zero, the specimen is considered failed.