Dynamic Fracture Criterion-Fracture Path of Cracks Emigrating from Two Circular Blastholes

To investigate the hooked or butterfly-shaped phenonmen, which is often observed in rock excavating and mining projects. An effective model is adopted to study the propensity of forming the hook pattern combination with dynamic fracture criterion in this paper. Considering the T-stress and crack velocity, the crack deflection angles under variable model parameters are analyzed, and the crack propagation paths are simulated. The results showed that: (1) with the increase of crack velocities, the crack deflection angles increase gradually regardless of the change of plane states, Poisson's ratios or model heights, (2) model height exhibits a significant effect on the crack deflection, as model height becomes less, the deflection angles becomes larger, (3) the hook phenonmen would happen under some circumstances. The results can provide some basic understanding in fracture plane control in mining fields.