The Dynamic Compressive Properties and Energy Dissipation Law of Sandstone Subjected to Freeze–Thaw Damage

Abstract

To investigate the dynamic compressive properties and the law of energy dissipation of freeze–thaw-damaged sandstone, static and dynamic compressive experiments were conducted. The influences of the number of freeze–thaw cycles and strain rate on strength characteristics, energy dissipation rate and the fractal dimension characteristics of sandstone were evaluated. Based on the peak energy dissipation rate, a freeze–thaw damage variable was established. The results show that peak strength increases exponentially with strain rate, and there exists a strain rate threshold. When strain rate is below this threshold, the increasing rate of the DIF slows down with the increase in the number of freeze–thaw cycles; when strain rate is higher than this threshold, the increasing rate of the DIF increases with the increase in the number of freeze–thaw cycles. In addition, the fractal dimension increases with the number of freeze–thaw cycles as well as the strain rate. Based on the freeze–thaw damage variable established, the damage degree of sandstone under freeze–thaw cycling can be characterized.