ABSTRACT
A new method of determining design strength parameters for landslide slope stability analysis is proposed. The authors assume that the strength decrease due to the increase of pore water pressure along the potential slip surface can be represented by a function of overconsolidation ratio(OCR) defined by the ratio of effective stresses before and after the increase of pore water pressure. Based on the assumptions mentioned above, the authors derive equations expressing the change of effective stress strength parameters (c, ϕ), which varies in between peak and residual state, as a continuous function of OCR. In addition, a practical method of determining strength parameters for stability calculation of landslide slope is proposed. In this method, the strength parameters are given by combining the conventional reverse calculation method, which has been frequently used in engineering practice, with the laboratory shear test results obtained by cyclic direct box shear apparatus.
