Research on the Dynamic Response of a Bedding Rock Slope Reinforced by Pile–Anchor Structures Under Earthquakes: A Case Study of a Section of the Duyun-Shangri-La Expressway Project in Ludian County, Yunnan Province, China

Pile and anchor structures are extensively employed for slope stabilization. However, their dynamic response under seismic loading remains unclear and current seismic designs primarily use the pseudo-static method. Here, a three-dimensional numerical simulation of the dynamic behavior of a bedding rock slope supported by pile–anchor systems under earthquakes is conducted. The dynamic calculation for the slope subjected to seismic forces with varying excitation directions and acceleration amplitudes is performed. The dynamic behavior of both the slope and the pile–anchor system is investigated with respect to the slope’s failure mode, the dynamic soil pressure behind the pile, the anchor axial force, the bending moment, and the lateral displacement of the pile. The results indicate that the anti-slide piles cause a reflective and superposition effect on seismic waves within weak rock layers. As the input seismic intensity increases, the axial force in the anchor cables also increases, with the peak axial force occurring during the main energy phase of the seismic waves. The dynamic soil pressure acting behind the piles varies with the stratification of the slope rock layers, with lower peak dynamic earth pressure observed in weak layers. The weak layers on the slope surface experience through-shear failure. Under strong seismic loading, the structural element state undergoes significant changes.