Dynamic response of pre-stressed rock with a circular cavity subject to transient loading

Scientists have attempted to investigate deep underground rock failure. A key challenge to study underground rock failure is the difficulty to survey its process. Therefore, a large number of important and insightful laboratory investigations of underground rock failure experiments are conducted. In this paper, an experimental method is proposed to explore dynamic failure process of pre-stressed rock specimen with a circular hole. The failure process of a rock specimen under different initial static stress coupled with dynamic loading is clearly illustrated by a high speed camera. The experimental results indicated that high static pre-stress coupled with dynamic loading induces rock debris to be ejected at the surrounding circular hole; however, lower static pre-stress coupled dynamic loading cannot induce rock failure. The dynamic stress concentration surrounding the circular hole by transient wave incidence was further demonstrated at the condition of half-sine wave loading. In this condition, the results demonstrated that combined action of static and dynamic stress concentrations induces the primary fractures of rock specimen.