Dynamic characteristics of skarn under the combined action of high static stress and frequent dynamic disturbance

In order to further study the failure mechanism of deep rock mass under the dynamic effect of excavation and blasting,the deformation characteristics,energy laws and failure model of skarn were investigated for the first time under the medium to high strain rate and the combined action of high static stress and frequent dynamic disturbance with an experimental system of coupled static and dynamic loads based on the SHPB device. The results show that the elastic modulus of rock increases with the increase of impacts and then it decreases,at the same time,the maximum strain exhibits an overall trend of decreasing first and then increasing. The elastic modulus drops sharply and the maximum strain shoots up when the last impact comes. The energy consumption per volume of rock is negative,which indicates that the rock samples exhibit a characteristic of energy release under impact dynamic action because a great much elastic strain energy stored in rock samples under high static stress action is released by the disturbance of impact dynamic action. The energy release per volume of rock increases first and then decreases with the increase of impacts. The skarn samples which have compact structure and high strength show a failure mode of splitting.