Stability analysis of a rock slope-pile-anchor coupled reinforcement system with bedding weak zones using an improved SPH method

The frequent failure of rock slopes with bedding weak zones necessitates the development of control strategies for disaster prevention. Anchors, combined with piles, are widely used in slope engineering, with their reinforcement effect highly dependent on specific technical parameters. However, current studies have not sufficiently investigated the evolution of the reinforcement effect in support structures under large deformation of rock slopes. In this study, an improved Smoothed Particle Hydrodynamics (SPH) method is developed, incorporating a particle domain search algorithm to simulate the pile-anchor structures. Besides, a fracture indicator is introduced to refine the smooth kernel function, enabling accurate tracking of damaged particles, while the contact behavior between damaged particles is rigorously defined using a point-to-point contact algorithm. The improved SPH method accurately reproduces the large deformation and progressive failure processes of the rock slope pile-anchor coupled reinforcement system (SPAS) with bedding weak zones. Anchors exhibit optimal performance within a specific range of anchor length, spacing, and inclination, thereby inducing failure mode transitions of SPAS. Notably, a U-shaped relationship with anchor inclination angle is observed in SPAS stability due to the reinforcement of intermediate-angle anchors on the dominant failure path. The reinforcement effect is also highly sensitive to the angle between anchors and bedding planes. We infer that the results provide guidance for slope reinforcement.