MECHANICAL PROPERTIES AND ACOUSTIC EMISSION CHARACTERISTICS OF GRANITE UNDER THERMO-HYDRO-MECHANICAL COUPLING

Exploring the mechanical properties and thermal cracking characteristics of rock under thermo-hydro-mechanical coupling in detail is of great importance for the safe excavation and stability of deep rock engineering. The mechanical properties and thermal cracking characteristics of granite under burial depths of 1000 m (confining pressure of 25 MPa) and 1600 m (confining pressure of 40 MPa) at a temperature of 110 degrees C and a pore water pressure of 10 MPa were studied.The results show that the elastic modulus decreases with increasing temperature un-der a confining pressure of 25 MPa, whereas under a confining pressure of 40 MPa, the elastic modulus increases with increasing temperature. As the pore water pressure increases, the elastic modulus decreases slightly. Poisson's ratio increas-es with increasing temperature below 40 celcius but decreases from 50-110 degrees C. Pois-son's ratio increases as pore water pressure increases. During the heating process, acoustic emission activity is first detected at 30-40 degrees C and is relatively stable from 40-90 degrees C. The acoustic emission activity increases sharply at 90-110 degrees C, and the thermal cracking threshold of granite under thermo-hydro-mechanical coupling is approximately 95 degrees C.

Automated summary

The study showed that the elastic modulus and Poisson's ratio of granite change with increasing temperature, while the pore water pressure has a slight effect on the elastic modulus. During the thermo-hydro-mechanical coupling process, acoustic emission activity increases with temperature.