Multi‐Criterion Stability Evaluation and Surface Boundary Method for Slopes

Slope failure generally starts from a single point, where a local failure surface forms, and then progresses to the overall failure. Based on this behavior, this paper proposes a multi‐criterion stability evaluation approach for describing progressive failure process of slope. The criteria for slope body failure (main thrust, surplus friction resistance, comprehensive displacement, and surplus displacement) are adopted to evaluate the stability during progressive failure process. The sliding surface boundary method (SBM), partial strength reduction method (PSRM), and free surface boundary conditions for slope stability numerical analysis are adopted, in which the gradual movement of the critical stress state of the sliding surface is simulated for selected boundary conditions, reproducing the entire process of gradual slope failure. The case study of the Dianzhan slope located in the Wufeng County in Hubei Province shows that the multi‐criterion stability evaluation approach adopting PSRM and SBM can better describe the evolution of various slope stability and failure characteristics. Comparing the stability coefficients calculated by traditional methods with the method proposed herein provides a novel theoretical basis of slope stability assessment, early instability warning, and slip‐resistant design.