Stability Analysis of Slopes under Surcharge Loading Using FE Stress Deviator Increasing Method-proposal of Stability Charts

Abstract

Given the well-known shortcomings of the traditional limit equilibrium methods (LEMs) in addressing slope stability issues, there has been a growing interest towards employing finite element analysis as a viable alternative in recent years. However, due to the inherent limitations in the conventional finite element analysis, the application of finite element method (FEM) as a strength reduction method (SRM) or as finite element limit analysis (FELA) does not consistently yield successful results. To improve the efficiency of finite element analysis for addressing slope stability problems, a new methodology called 'Stress Deviator Increasing Method' (SDIM) has been recently proposed. It involves gradual expansion of the mobilized stress Mohr's circles until the soil failure takes place according to a predefined non-convergence criterion. In this paper an attempt is made to analyze the effects of surcharge loading on both factor of safety (FOS) value and location of the slip line using the finite element by SDIM by carrying out a restricted parametric study. Specifically, the effects of surcharge loading magnitude, the proximity of the surcharge with respect to the slope edge and the load distribution span were thoroughly analyzed and documented in the light of FOS values and plastic strain regions. The paper ends by proposing design stability charts in which, for a given surcharge magnitude and a geometric configuration, the user is able to determine the FOS for a combination of soil strength parameters.