A Three-Dimensional DEM Method for Trajectory Simulations of Rockfall under Irregular-Shaped Slope Surface and Rock Blocks

0 INTRODUCTION Rockfall is a common geological hazard that poses a serious threat to residents and infrastructures (Gao et al., 2022; Ye et al., 2022). The precise prediction of rockfall trajectories is essential to the design of protection engineering structures of rockfall (Ma et al., 2021). The discrete element modelling (DEM) is increasingly used to analyse rockfall movement paths. Ma et al. (2022) used Rockyfor3D software to obtain the possible trajectory of falling rock blocks. Based on the two-dimensional (2D) particle flow code (PFC2D), Wei et al. (2010) developed a linear contact model and viscous damping contact model to simulate the motion process of collapse mass. Wang (2020) used the three-dimensional (3D) particle flow code (PFC3D) to simulate the trajectory of individual falling rock blocks. Rong et al. (2020) combined PFC3D with Rockfall software to obtain better prediction of rockfall trajectory.