Coupled CEL-FDEM modeling of rock failure induced by high-pressure water jet

Abstract

The coupled Euler-Lagrange (CEL) method and finite-discrete element method (FDEM) are adopted to simulate the rock fracture process induced by high-pressure water jet and to solve the problems of highly nonlinear, fluid-solid coupling and large deformation. The water is characterized by the CEL model, and water can flow freely in the Euler mesh, which can better simulate the actual shape of water jets. The rock is integrated into the FEDM model, which is produced by embedding zero-thickness cohesive elements. The traction-separation criterion of the cohesive element is used to simulate the rock damage. In the simulation process of rock fracture by the water jet, infinite elements are used to realize the non-reflection boundary conditions, simulate real working conditions, and improve the calculation reliability. Furthermore, the VUSDFLD user subroutine is used to delete the elements outside the box and reduce the impact of the fallen rock debris on simulation speed, thus improving calculation efficiency. The formation process of rock impact pits and slits, as well as the velocity and distribution of water jets, are studied by comparing the simulation and experiments of water jet fixed-point impact and moving cutting. Subsequently, the fracture mechanism of rock under the water jet is revealed, presenting new possibilities for studies into rock fractures by high-pressure water jet.