Multiple Rockfall Impacts on a Sand CushionComposed of Non-Spherical ParticlesUsing Three-Dimensional DEM

Abstract

Abstract Rockfall disasters are one of the primary geological hazards on Earth, and a rock shed with a sand cushion plays a crucial role in rockfall protection. Previous studies have mainly focused on the dynamic response of rockfall on the sand cushion for a single impact. However, in actual rockfall disasters, it is common for the sand cushions of rock sheds to suffer multiple rockfall impacts. This study utilized a three-dimensional discrete element method to investigate the dynamic response of rockfall on the sand cushion for multiple impacts from different heights. For the first time, non-spherical particles were used to simulate the sand particles composing the sand cushion, and comparative analysis confirmed that non-spherical particles better replicate the characteristics of the sand cushion compared to spherical particles. Subsequently, in-depth investigations were conducted on two scenarios: multiple rockfall impacts at the same position and multiple rockfall impacts at different positions, and specifically analyzed the impact force and penetration depth. The results indicated that when the rockfall impacts multiple times at the same position, both the maximum impact force and the maximum penetration depth increase with the number of impacts. When the rockfall impacts multiple times simultaneously at different positions, they have no mutual influence when the distance between the two rockfall impacts is greater than 6R. This study demonstrates the significance of studying multiple rockfall impacts, providing valuable insights for the rational design of rock sheds for rockfall protection and performance evaluations in the face of multiple rockfall disasters.