Dynamic properties of granite subjected to coupling action of impact loading with actual temperature

Abstract:

To investigate the thermodynamic property of rock, the impact compression tests of granite within different temperatures were performed under different strain rates (50-250 s^-1). Results show that the strain-rate sensitivities subjected to different temperatures are quite different. When the temperature rises to 700 ℃, the effect of strain rate on compressive strength is the weakest, while that on peak strain is obvious. The effect of strain rate on elastic modulus tends to have no regularity. The elastic modulus increases with the increase of strain rate at 20 ℃ and 700 ℃, but it takes on a downward trend at 300 ℃ and 500 ℃. There is little change in the dynamic compressive strength at 300 ℃ compared to the room temperature. When the temperature reaches 500 ℃, the thermal damage becomes obvious, the dynamic compressive strength and elastic modulus significantly reduce, but the peak strain increases. At 700 ℃, the thermal damage phenomenon is serious, and the compression strength and elastic modulus sharply decrease. In addition, with increasing the actual temperature, the color of the tested rock changes and its breakage degree also deepens.