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.

Investigation on lunar water ice simulant under impact load is essential for future lunar exploration in the south polar region of the moon. In this paper, the impact dynamic properties of lunar water ice simulant are investigated by using an FDM-DEM coupling method, and the effectiveness of the method and the rationality of parameters are verified by comparing simulation results with experimental results. The results indicate that the FDM-DEM coupling method can effectively simulate the impact dynamic properties of lunar water ice simulant, and find that the lunar water ice simulant exhibits strain rate enhancement effect, the enhancement effect is more pronounced with increasing water content. Furthermore, the quantitative damage degrees and visualized failure patterns are obtained, the damage degrees and failure patterns of lunar water ice simulant show a strong dependence on the water content and impact velocity. But when the water content is 5%, the damage degree is close to 95% and basically no longer affected by impact velocity. (c) 2024 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.