Stability analysis of soft-hard interbedded anti-inclined rock slope under rainfall based on deformation compatibility

Abstract Rock slope instability is a prevalent geological hazard that imposes significant adverse impacts on engineering activities. Although existing studies have focused on homogeneous rock slopes, the theoretical models for quantifying the stability of soft-hard interbedded anti-inclined slopes remain underdeveloped, primarily due to the complex force transfer mechanisms involved. This study proposed a novel theoretical model for the stability analysis of soft-hard interbedded anti-inclined slopes under rainfall conditions. The framework models stratified rock layers as layered cantilever beams with material heterogeneity. Based on the principle of deformation compatibility, it comprehensively accounted for interlayer force transfer and strength degradation resulting from differential deformations among rock layers. Furthermore, it integrated the critical instability length induced by the self-weight of rock layers to determine the fracture depth. The proposed method was validated against engineering case studies and physical model tests, with error falling within an acceptable range. Compared to existing theoretical methods, the proposed method provided a more realistic representation of the slope’s stress field. The analysis results demonstrate that rainfall not only reduces the inclination angle of the failure surface but also leads to an approximate 30% decrease in the safety factor. The proposed theoretical model is particularly useful for quickly calculating the stability of soft-hard interbedded anti-inclined rock slope under rainfall conditions, compared to complex and time-consuming numerical simulation calculations.