The study of the evolution law of basic physical parameters and dynamic compression performance of deep granite under the environment of the heating-cooling cycle is of great significance for the stability evaluation of deep underground engineering and the development of deep resources. In this study, heating-cooling cycle tests and dynamic compression tests were conducted on a large number of fine-grained granite specimens with heating temperatures from 200 to 600 °C and times from one to twenty times using a box-type high-temperature muffle furnace and Hopkinson pressure bar (SHPB) test system, and the evolution law of basic physical parameters and dynamic compression mechanical properties of fine-grained granite were studied using theoretical and fitting analysis. The test results showed that: the changes of the basic physical parameters of granite have obvious temperature effect; 600 °C is a threshold value for the changes of each physical parameter of granite; the sensitivity of each physical parameter to the number of heating and cooling cycles is small before 600 °C; and the sensitivity of each physical parameter to the number of heating and cooling cycles significantly increases at 600 °C. The dynamic compressive strength and elastic modulus of granite decreased with the increase in heating and cooling cycles, and the maximum decrease rate was 89.1% and 85.9%, respectively, and the strain rate linearly increased with the increase in heating and cooling cycles, and the maximum strain rate was 123 s-1. The temperature, the number of heating and cooling cycles, and the impact air pressure, all had significant effects on the damage mode and crushing degree of granite.
Keywords: cooling mode; dynamic compression properties; heating-cooling cycle; microscopic damage; physical parameters.