不同加载速率下冻融砂岩的动态劈裂特性.

In order to study the effects of loading rate and freeze-thaw cycles on the dynamic splitting characteristics of sandstone, static and dynamic splitting tests with different loading rates were conducted on sandstone subjected to 0, 25, 50, 75 and 100 freeze-thaw cycles, and the static and dynamic tensile strength of freeze-thaw sandstone, as well as the change law of dissipation energy under impact load were discussed. The results show that the static and dynamic tensile strength, the P-wave velocity and the mass loss rate of freeze-thaw sandstone deteriorate with an increase in the number of freeze-thaws cycles. The dynamic strength increase factor (DIF) increases with the increase of freeze-thaw cycles and loading rate, and a higher degree of the freeze-thawing damage in sandstone results in a more significant increase in DIF with loading rate. The dynamic tensile strength prediction model based on freeze-thaw damage and loading rate can reflect the strength change of sandstone effectively. The greater the freeze-thaw damage of sandstone, the faster the change of dynamic tensile strength with loading rate. The dissipation energy under impact load decreases with the increase of freeze-thaw cycles and increases with higher loading rate. [ABSTRACT FROM AUTHOR]