A hybrid finite-discrete element method for modelling cracking processes in sandy mudstone containing a single edge-flaw under cyclic dynamic loading

Abstract

Rock mass deformation and failure are macroscopic manifestations of crack initiation, propagation, and coalescence. However, simulating the transition of rocks from continuous to discontinuous media under dynamic loads remains challenging. This study proposes a hybrid finite-discrete element method (HFDEM) to model crack propagation. Uniaxial compression tests on sandy mudstone with a single edge-flaw are simulated using HFDEM, and the results are compared with laboratory tests. The effects of pre-existing flaw inclination angle and dynamic loading frequency on the crack process are investigated. Results show that under dynamic loading, rock samples exhibit significantly higher compressive strength compared to quasi-static loading, which increases with dynamic frequency. Crack initiation angle also increases with flaw inclination angle and dynamic frequency. Experimental and numerical simulation results demonstrate crack initiation at the defect's tip, formation of wing cracks, and a combination of tensile and shear failure modes. The comparative analysis shows that HFDEM successfully captures crack interaction mechanisms and accurately simulates the overall failure behavior of cracked specimens. This study provides valuable insights into crack development and failure of rocks under seismic loads, offering guidance for engineering practices.