Energy dissipation characteristics of high-temperature granites after water-cooling under different impact loadings不同冲击荷载下高温-水冷却花岗岩能量耗散特征研究

Studying the energy dissipation characteristics of high-temperature rock after cooling with water during geothermal drilling construction is crucial to improving rock crushing efficiency. The energy dissipation characteristics of granite were investigated by conducting dynamic tests with a split Hopkinson pressure bar (SHPB) system under different impact loadings. The granite specimens were subjected to temperatures from 25 °C to 1000 °C. The micromorphology and pore distribution of granite were obtained by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests. The porosity change trend could be divided into two stages at 400 °. The micropores and small pores accounted for over 75.0% before 400 °C The medium pore proportion increased rapidly when T≽400 °C. In addition, the dynamic peak stress and peak strain increased with incident energy, while the trend of the change in the dynamic elastic modulus was not apparent. The proportion of dissipated energy showed an upwards trend when the heating temperature varied from 25 °C to 800 °C, while the absorbed energy of granite heated to 1000 °C decreased. The energy utilization efficiency was the highest when the strain rate was between 100 s−1 and 120 s−1.