Two-wedge slope stability analysis considering a nonvertical wedge interface

Two-wedge slope failure can occur in various geotechnical issues. The analytical method is a quick and economical way for a preliminary evaluation of slope stability. In existing analytical solutions, the shear mobilization ratio of soil at the wedge interface is seldom considered, and the wedge interface is usually assumed vertical. In this study, the soil shear mobilization ratio and the wedge interface angle are incorporated into a new analytical solution. The effects of wedge geometry, soil properties, and base interface properties on stability are then investigated. The results show that an increasing shear mobilization ratio can increase the safety factor. While as the wedge interface angle increases, the factor of safety will first decrease to a minimum value and then increase. Considering the combined effects of soil shear mobilization ratio and wedge interface angle, an upper and a lower bound of the factor of safety can be determined to assess the two-wedge slope stability. The proposed analytical solution is verified by checking its capability of simplifying itself to existing solutions. Furthermore, the factor of safety obtained from numerical simulations for cases under two-wedge failure falls well within the range calculated by the analytical solution, suggesting the applicability of the proposed analytical solution.