Study on Damage and Failure Law of Thermostatic Granite under Loading Rate Effect

To study the loading rate effect of the constant thermostatic granite, the 60 ℃ constant thermostatic granite sample was taken as the experimental object, and the granite uniaxial compression test under different loading rates was carried out. The acoustic emission technology was used for real-time monitoring and numerical simulation calculation, and the mechanical properties and failure evolution law of the sample were analyzed. The results show that: with the increase of loading rate, the elastic modulus of granite decreases first and then increases, and poisson’s ratio increases first and then decreases. At the loading rate of 0.005 mm/s, the AE signal curve of the specimen is smooth and grows slowly; at the loading rate of 0.01 mm/s and 0.015 mm/s, the AE signal curve curvature increases sharply, while at the loading rate of 0.02 mm/s, the AE signal rises steeply. Under different loading rates, the distribution of tensile cracks is close to the AF axis, while the distribution of shear cracks is far away from the AF axis, and the distribution of tensile cracks is far more than that of shear cracks. The AE RA-AF evolution characteristic analysis and numerical simulation analysis have well confirmed that the failure mode of granite under low loading rate is mainly tension-shear mixed failure, while the failure mode under high loading rate is mainly tension-shear failure, which is highly consistent with the experimental results.