抄録
It is highly important to estimate the shear strength parameters at the critical slip surface of landslide in order to design effective countermeasures. This study aims to propose a new method for estimating a set value of shear strength parameters which satisfies two conditions: the calculated critical slip surface coincides with the actual slip surface and the obtained safety factor is equal to 1.0. Dynamic programming using simplified Janbu's method was applied as a tool to locate the critical slip surface that yields minimum value of safety factor. A specific case of submerged landslide was examined to demonstrate the efficiency and accuracy of the proposed method. Furthermore, the same method of analysis was applied to examine another 47 cases of landslides. It found that two relationships, one between the estimated cohesion (c) and the average depth of landslide and the other one between the internal friction angle (φ) and the inclination of slip surface, can be used for practical estimation of shear strength parameters. Further, the estimated shear strength parameters of submerged landslides have a reasonable agreement with the change in safety factor by the rising of reservoir level.
