Shear Strength and Energy Evolution of Granite under Real-Time Temperature

The shear mechanical properties of rock under high temperature and high pressure are key issues in geothermal energy development. In order to explore the variation in shear mechanical properties of rock under high temperature and high pressure, the shear experiments of granite under real-time temperatures and normal stresses were carried out using the servo-controlled true triaxial experimental system for rock shearing testing and acoustic emission technology. The results show the following trends: (1) the peak shear strength of granite increases slightly first and then decreases sharply with real-time temperature, with 200 °C considered as the threshold temperature for the peak shear strength of granite. When the temperature is constant, the shear strength of granite increases linearly with the increase in normal stress. (2) Before 200 °C, the shear modulus of granite decreases slowly with the increase in temperature and decreases rapidly after 200 °C. The shear modulus always increases linearly with the increase in normal stress. (3) Under the coupling effect of real-time high temperature and normal stress, the cumulative acoustic emission energy released during the shear deformation of granite gradually decreases with temperature, and the main failure mode of granite gradually changes from tensile failure to shear failure.