Analysis of coupled shallow and deep sliding of slopes induced by earthquake based on limit equilibrium method

The displacement of seismic slopes is an important index to evaluate their stability. The existing seismic displacement analysis methods are mainly aimed at the slope with single sliding surface. Based on the Spencer limit equilibrium analysis principle, a method for calculating the seismic displacement of slopes with double non-planar slip surfaces is proposed. By using the limit equilibrium slice method considering the seismically inertial force, the dynamic equilibrium equations for the double-sliding block system during earthquake shaking is established, and the interaction between shallow and deep sliding bodies in the sliding process caused by earthquake is considered. The results by the proposed method are compared with the numerical results of finite difference software FLAC, which proves the rationality and correctness of the method in describing the coupled shallow and deep seismic sliding pattern of slopes. The proposed method is then applied to the layered soil accumulation slope and the Laozheshan slope of section Egang of Sichuan-Tibet Highway, respectively. The feasibility of the proposed method for calculating the seismic displacement of actual slopes with double potential slip surfaces is clarified.