Failure characteristics and stress distribution of pre-stressed rock specimen with circular cavity subjected to dynamic loading

A modified Hopkinson pressure bar system with coupled static and dynamic disturbance is used to study the failure characteristics of a granite specimen with a cavity. Different coupled static pre-stress and dynamic loading experiments are conducted. The dynamic failure processes and characteristics of the granite specimen with a cavity under the test conditions are summarised. High speed camera images showed that moderate static pre-stresses of 27 MPa and 36 MPa coupled with moderate dynamic loading of 168 MPa lead to violent rock failure, which is the same as rock-burst. In addition, the coupled static pre-stress and dynamic loading processes are simulated, and the dynamic stress concentration factors (DSCFs) and strain energy density (SED) around the cavity under different coupled loads are investigated. The simulation results show that violent rock failure occurs at a higher DSCF and SED. The experimental and numerical setup used in this study provides useful results for investigating the characteristics of rock failure under coupled static and dynamic stress conditions.