Locating the Critical Sliding Surfaces of Horizontal Layered Rock Slopes by Analytical Approach

ABSTRACT Identifying the critical sliding surface (CSS) of a rock slope is one of the key procedures in slope stability analysis. In previous studies, the CSS was typically identified through heuristic algorithms or manually predefined configurations. This study proposes an analytical method to determine the CSS in horizontal layered rock slopes. First, the CSS of a horizontal layered rock slope is characterized by the dip angle of the sliding surface ( θ min ). The horizontal projected length ( x ) of the sliding surface and safety factor ( F S ) of slope are established as independent variable and dependent variable, respectively. Subsequently, the relationship between the F S and x is formulated by use of the limit equilibrium method (LEM). The θ min is determined by taking the derivation of F S with respect to x . Furthermore, both F S and θ min of the upper‐soft lower‐hard and the upper‐hard lower‐soft rock layers sliding modes of the slopes are investigated. The accuracy of the proposed method is verified by discrete element method (DEM) and numerical analysis. Finally, the parameter sensitivity analysis of horizontal layered rock slopes stability is conducted. The results shows that (i) The θ min decreased gradually as c increased, but increased gradually as φ increased in single‐layered rock slope. (ii) In a double‐layered rock slope, as c 1 / c 2 increased, θ min showed initially decreasing and then increasing, while as φ 1 / φ 2 increased, θ min showed decreasing. (iii) The rock slopes with upper‐soft lower‐hard are safer than those with the upper‐hard lower‐soft rock layers. This study fills an existing research gap of analytical solutions of CSS in layered rock slopes.