Numerical simulation of the rock fragmentation process induced by two drill bits subjected to static and dynamic (impact) loading

Rock fragmentation processes induced by double drill bits subjected to static and dynamic loading are examined by a numerical method. Micro-heterogeneities of the rock are taken into account in this numerical model. For the static case, the simulated results reproduce the progressive process of brittle rock fragmentation during indentation. For the dynamic case, numerical simulations represent radial cracks, incipient chips, pulverized zones, and shell cracks. Comparing the static and dynamic cases, the dynamic loading can lead to rock fragmentation more efficiently. In addition, numerical results indicate that the dynamic pressure (Pmax) plays an important role in the failure process of specimens with two indenters. Furthermore, the heterogeneity of the rock can also affect the failure modes of the rock when two indenters are used. Finally, the numerical results demonstrate the effect of the spacing between the indenters on the rock.