An FDM–DEM coupling method for analyzing the mechanical behavior of a slope reinforced by piles

The failure of piles often starts from localized damage caused by stress concentration. However, little is known about such progressive process of pile failure involving crack initiation and propagation. Here, we propose a finite difference method (FDM)–discrete element method (DEM) coupling method to simulate the mechanical behavior of a slope reinforced by piles. The FDM is employed to model the macroscale behavior of the slope, while the DEM is employed to reveal the micro-mechanism of the progressive failure of anti-slide pile. The method is validated and then is used for mechanical analysis of a pile–slope system. The response of displacement, strain, and soil pressure is analyzed to investigate the failure mechanism of a slope reinforced with piles. The results show that slope deformation causes the initiation of cracks in the pile located proximal to the sliding surface, and the crack tip gradually expands as the breakage of the contact force chain in the pile until the pile completely fails. The progressive failure process of the pile is reproduced through monitoring the evolution of contact forces and the breakage of the contact force chains. The simulation of the interaction between soil and piles can be realized using the large-strain mode. Compared with conventional methods, the FDM–DEM coupling method considers detailed microscopic information with a lower computational cost, and provide a powerful tool for revealing the mechanical behavior of pile-reinforced slopes.