Slope stability analysis using convergent strength reduction method

Abstract

The strength reduction method (SRM) is becoming more and more popular in the stability analysis of slopes. Nevertheless, the criterion for slope failure associated with SRM is controversial, and divergence exists while approaching to the limit equilibrium state of slopes. In this study, the slip body is discretized with constant boundary elements. Since at least one element on the slip surface, referred to as the critical element, should keep still till the slope reaches the limit equilibrium state, the critical element is forced to be fixed throughout while other elements on the slip surface are specified to be contact elements during the strength reduction. In this way, convergence is always assured in the open-close iteration of contact between the slip body and the slip bed, no matter how much the strength of the slip surface is reduced. The limit equilibrium state is defined to be the moment at which the strength redundancy of the critical element vanishes. The method of bisection is applied to find out the factor of safety (FOS). The proposed method is applied to those benchmark examples and the comparison is made with the limit equilibrium methods (LEM).