Two-dimensional slope stability analysis by limit equilibrium and strength reduction methods

In this paper, the factors of safety and the locations of critical failure surfaces obtained by the limit equilibrium method and strength reduction method are compared for various slopes. For simple homogenous soil slopes, it is found that the results from these two methods are generally in good agreement except when ϕ′ is zero. It is also found that the strength reduction method (SRM) is usually not sensitive to the dilation angle, soil moduli or the solution domain size and the choice of these parameters is not critical in the analysis. While the SRM may perform well in many cases, two major limitations of this method are found in this study: it is sensitive to the nonlinear solution algorithm for the case of a soft band with frictional material and it is incapable of determining other failure surfaces which may be only slightly less critical than the SRM solution but still require treatment for good engineering practice.