Searching for multistage sliding surfaces based on the discontinuous dynamic strength reduction method

A loose slope structure and multiple free faces in a step-like landform are important engineering geological factors that cause multistage landslides. Tensile cracks that develop inside the slopes and the free faces created by excavation will have an impact on determining the location of potential multistage sliding surfaces. However, it is difficult to accurately locate sliding surfaces with tensile cracks in multistage landslide stability analysis. To solve this problem, a new search method is proposed for multistage sliding surfaces: the discontinuous dynamic strength reduction method (DDSRM). A slope will exhibit discontinuous failure when tensile cracks form. Therefore, the DDSRM simultaneously considers the shear and tensile failure modes. In the DDSRM, the tensile cracks on the first sliding surface are set as a discontinuous surface to stop the development of these cracks. The DDSRM is applied to a multistage landslide caused by excavation on a slope located in Southwest China. The results show that the plastic zone obtained with the DDSRM is small and that all of the potential sliding surfaces can be identified by setting the tensile crack as a discontinuous surface. Thus, the DDSRM provides a new way to search for multistage sliding surfaces.