Crack Propagation and Bursting Liability of Energy-Storing Coal Under Varying Impact Disturbances
摘要
Dynamic disasters occur frequently in deep mining. Dynamic compression tests were conducted on energy-storing coal with varying impact velocities to study the mechanical properties and crack propagation of energy-storing coal under dynamic impact disturbances. The deformation characteristics and crack propagation of energy-storing coal were analyzed, and their energy dissipation and bursting liability are discussed here. The experimental results revealed that the peak strength of the energy-storing coal ranged 35.70–59.85 MPa and rose as a power function with increasing impact velocities. The failure modes of the energy-storing coal varied from axial splitting to multiple fracturing with increasing impact velocities. The crack propagation fractal dimension varied from 1.37 to 1.84 and showed a growing trend during the dynamic failure process. The crack propagation fractal dimension rose with increasing impact velocity. The incident, absorbed, and transmitted energy positively correlated with impact velocity, and the absorbed energy evolved in three stages: slow growth, rapid growth, and stable stage. The modified realistic energy release rate (RERRC) of the energy-storing coal ranged 3.36–7.84 kJ·m-3·μs-1 and positively correlated with impact velocity, which can better characterize bursting liability. The findings offer a theoretical foundation for the mechanism of dynamic instability in deep mining.