Abstract:In this paper, the unweathered granite was used as the experimental object, and the triaxial compression test was carried out on the high temperature and high pressure triaxial mechanical experiment system. The effects of rock sample temperature, confining pressure on peak strength and elastic modulus at three loading rates were analyzed. The loading rate effect of the thermal damage evolution law is established, and the cold damage equation of granite is established. The results show that: At 100 ℃, the loading rate increases, the rock in the low confining pressure zone changes from ductile to brittle, and the progressive failure changes to sudden instability; at 500 ℃, the loading rate increases, and the elasticity of the low confining pressure zone The modulus hardening is obvious, the instability mode is quasi-burst instability; With the increase of loading rate, the peak intensity increases significantly at low temperature 30 ℃~200 ℃, at higher temperature 200 ℃~500 ℃. The increase of peak intensity decreases. As the confining pressure increases, the loading rate decreases the peak strength enhancement. Under the rock temperature conditions, the correlation between loading rate and elastic modulus is not significant; elasticity at low confining pressure. The modulus increases greatly, and the elastic modulus increases at a high confining pressure. As the loading rate increases, the relationship between elastic modulus damage and rock temperature decreases from linear to nonlinear critical confining pressure.