Abstract: In this paper, the basic principles of the numerical back analysis of slip zone soil properties are introduced. The finite difference plane strain model is used to back predict the shear strength parameters of a highway slope in the critical stability conditions. Two sections with the same distance from the main axis of the landslide are taken respectively. First, one set of the shear strength parameters c (or φ) is assumed, and the other set of parameters φ (or c) is repeatedly tested and adjusted until the numerical analysis reaches critical state. At the critical condition, factor of safety K=1 is assumed, a set of corresponding shear strength parameters is obtained. Several groups of corresponding c and φ values are analyzed repeatedly using the same method. Then the data of two sections are plotted in the same coordinate system, and the intersection point is the shear strength parameters of the slope. The results show that it is feasible to estimate the shear strength parameters in the sliding zone soil by the back analysis using the numerical simulation method.

Key words: SoilSliding Zone, Shear Strength, Numerical Simulation, Back Analysis