Influence of freeze-thaw cycles on dynamic compressive strength and energy distribution of soft rock specimen

The effect of freeze-thaw cycles on the dynamic uniaxial compressive strength and energy distribution parameters including the specific energy absorbency rate (ES), energy reflectivity (ER) and energy transmitted rate (ET) are experimentally investigated in this research. The dynamic compression tests on two kinds of soft rock (i.e., sandy mudstone and mudstone) after different freeze-thaw cycles (i.e., 0, 3, 6, 9, 12, and 15 times) have been carried out with splitting Hopkinson pressure bar setup. In addition, the dynamic freeze-thaw damage coefficient (Kdf) and freeze-thaw damage variable (D) are defined. The experimental results show that the dynamic uniaxial compressive strength decreases logarithmically with increasing number of freeze-thaw cycles. The dynamic freeze-thaw damage coefficient (Kdf) of mudstone is larger than that of sandy mudstone at the same freeze-thaw cycles. All these energy distribution parameters are significantly influenced by the freeze-thaw cycles. There has a negative linear correlation between dynamic uniaxial compressive strength and freeze-thaw damage variable (D).