Discrete Element Analyses of a Realistic-shaped Rock Block Impacting Against a Soil Buffering Layer

This study is devoted to understanding the impact of irregularly shaped rock blocks against a soil buffering layer above a rock shed via numerical simulations by discrete element method (DEM). In the DEM model, the rock block is represented by an assembly of densely packed and bonded spherical particles with the block shape reconstructed from the laser scanning results of a real rock block. The soil buffering layer is modeled as a loose packing of cohesionless frictional spherical particles, while the rock shed is simplified as a layer of fixed particles. The DEM model is first validated by modeling the impact of a cubic block against a soil buffering layer. Then, it is employed to investigate the dynamic interaction between a realistic-shaped rock block and the soil buffering layer. The numerical results show that the geometry of the contact surface between the rock block and soil layer can play a significant influence on the impact force of the rock block and the force acting on the rock shed. For the tested conditions, the distribution of stress on the rock shed can be well described by the Gaussian function, which seems to be independent on the geometry of the contact surface. In addition, the simplification of realistic-shaped rock blocks as spheres in the traditional DEM modeling approaches can significantly underestimate of the impact force. The established modeling strategy serves as a starting point for investigating the rock block shape. The proposed results can contribute to the choice of buffering layer for designing the rock shed.