Effects of Freeze–Thaw Cycling on Dynamic Compressive Strength and Energy Dissipation of Sandstone

Abstract

In this study, the dynamic compressive strength and dissipated energy of rocks were investigated under hydrostatic pressure after different freeze–thaw cycles (FTCs). A split Hopkinson pressure bar (SHPB) with a lateral confining pressure chamber was used for the dynamic testing of sandstone specimens. The results indicated that under a certain loading rate and hydrostatic pressure, both the dissipative energy and dynamic compression strength of rocks decreased with the increase in the number of FTCs. The hydrostatic pressure significantly increased the dissipated energy and dynamic compression strength of rocks, and the enhancement became more pronounced as the number of FTCs increased. By analyzing the energy and damage characteristics of the specimens, after 40 FTCs, the internal damage of the specimens became critical and desensitized the dissipated energy to the loading rate. Based on the testing results, an empirical function was proposed to describe how the dissipated energy was related to the number of FTCs, hydrostatic pressure, and loading rate. It was demonstrated that the dissipated energy had a negative linear relation with FTC, which was enhanced by confinement. The dissipated energy of the specimen corresponded to the dynamic compression strength according to a quadratic function.