Energy Evolution and Failure Tendency Index of Beishan Granite

To investigate the energy evolution of granite obtained from the Beishan pre-selected area for geological disposal of high-level radioactive waste under different loading and unloading paths, an indoor triaxial test on Beishan granite round column specimens under different initial surrounding pressure and different loading and unloading conditions was conducted. Indoor triaxial tests were carried out on the granite specimens with different initial envelope pressure and different loading and unloading conditions, the test data were processed and compared, and a new type of rock damage energy propensity index was established. The results show that the total strain energy, elastic strain energy and dissipative strain energy of the critical damage of the rock increase with the increase of the initial surrounding pressure; there is a strong correlation between the characteristic parameters of acoustic emission and dissipative energy during the damage of the rock; the rock failure mode under the unloading condition is divided into internal damage failure and axial strain damage failure; the energy propensity index of rock damage increases first and then decreases under different unloading test conditions, and the higher the efficiency of converting elastic strain energy into dissipative energy, the smaller the energy propensity index and the higher the degree of rock damage.