Abstract: In order to simulate the deformation characteristic and motion forms of rock mass, a three-dimensional deformable spheropolyhedral discrete element method is presented, by combining the spheropolyhedral discrete element method (DEM) and the finite element method (FEM). This method effectively captures the irregular characteristics of the block, simplifies contact detection, and provides accurate representations of block deformation. The contact detection object is simplified from individual contact pair to the entire element during tangential contact force calculation, which significantly improves the computational efficiency. In order to analyze the deformation characteristics of the block, the finite element mesh is divided inside the discrete element of the block, with the outermost mesh defined as the minimum contact element. Contact forces are translated to equivalent nodal contact forces using the direct average method. Nonlinear finite element methods accurately simulate element deformation, overcoming the rigid body assumption of spheropolyhedra. Five numerical examples are simulated to verify the accuracy of the proposed method in capturing the deformation, motion morphology and mechanical characteristics of the element.

Key words: spheropolyhedral discrete element method, finite element method, deformable element, equivalent nodal force