Abstract:
In order to study the mechanical properties of hard rock with frequent dynamic impact under different axial static pressure conditions, the dynamic impact test is carried out on skarn samples which are taken from the deep (900 m) of Dongguashan copper mine.The test results show that the axial static pressure has a significant effect on the cumulative number of impacts on the rock, the cumulative impact times and the axial static pressure have a quadratic function.With the increase of the number of impacts, the elastic modulus is decreased.The elastic mode shows different variation characteristics with the number of impacts under different axial static pressures.The peak stress decreases with the number of impacts increases and the axial static pressure has a significant influence on the peak stress.The samples show different energy dissipation laws under different axial static pressures.The samples appear to absorb energy when the axial static pressure is 75 MPa.The samples always release energy under impact when the axial static pressure is 85 MPa and 100 MPa.The elastic strain energy stored inside the specimen can fully provide the energy required for the specimen to be destroyed under high stress.The rock is easily destroyed under the induction of dynamic disturbance, and this phenomenon provides a basis for revealing the mechanism of rock burst in deep mining.