Dynamic behavior of new anchor cable ribbed rockfall retaining walls on rock shed: rockfall impact

Abstract

This study investigates the dynamic behavior between a rockfall and a new anchor cable ribbed rockfall retaining walls on a rock shed, which is designed to meet project requirements due to the tremendous space occupation of the protection structure, via numerical simulations by the coupling between PFC3D (discrete element method, DEM) and FLAC3D (finite element method, FEM). In the model, the slope model was imported after the point cloud of the slope was processed. The novel structure is modeled by the finite element method (FEM) through the zone element, while the rockfall and the buffer layer are modeled by the discrete element method (DEM) through the ball element. The dynamic movement of rockfall was traced, and the impact position and velocity were obtained on the structure. The numerical results show that three stages of the rockfall movement were modeled, namely, movement, impact, and stagnation. The rockfall falls on the slope, impacting the buffer layer on the top of the rock shed, before rebounding to the anchored rockfall retaining walls (with a height lower than 2 m). Then, the stress and deflection can be unified and related to the impact velocity of rockfall to examine the stability of the structure. In addition, the rockfall radius is the dominant parameter in the three parameters (rockfall shape, rockfall radius, and impact velocity). While the study focuses on a specific case study, the results provide valuable guidelines for future applications of the proposed combined structure for railway transportation protection.