Enhanced limit method for slope stability analysis

Abstract

The aim of this paper is to investigate the Enhanced Limit Method, which combines finite element and limit equilibrium analysis in slope stability studies, and to describe its use in practical geotechnical applications. The study covers a critical review of the use of the finite element stress field inside a limit equilibrium analysis to assess slope stability. Particular emphasis is given to the common assumption of constancy of the factor of safety along the critical slip surface and the incorporation of the dilatancy angle, tensile strength, and Poisson's ratio. This study has shown that the factor of safety along the sliding surface is not the same, therefore, the assumption of constant safety factor of the Limit Equilibrium Method should be used with caution. It is found that the dilatancy and tensile strength have negligible effects on the determination of the factor of safety. They may, however, influence in some extend the location of the critical slip surface, particularly at the crest of the slope. The Poisson's ratio slightly affects the shear stresses without significant influence in the computation of the factor of safety. The representation of the local safety factors is better shown with the enhanced method, this feature is important because the location of the most critical zones can be assessed and used for guiding the implementation of remedial measures.