Crack Propagation Process and Seismogenic Mechanisms of Rock Due to the Influence of Freezing and Thawing

Abstract

A common problem in cold regions is the influence of freeze–thaw damage on the stability of rock engineering. Therefore, a series of uniaxial compression tests of sandstone after freeze–thaw treatment was carried out in this study. The purpose was to express the initial damage of rock after freezing and thawing treatment more quantitatively and to study the influence of freeze–thaw damage on the rock crack growth process to provide some reference for the stability evaluation of rock engineering in cold regions. The results showed that the number of freeze–thaw cycles and the lowest freeze–thaw temperature had a significant effect on the rock damage and characteristic stress value, and the number of cycles had a more obvious effect: with an increase in the number of freeze–thaw cycles and a decrease in the freeze–thaw temperature, the initial damage DNT had an increasing trend. In addition, the intrinsic mechanism of the freeze–thaw effect on the rock characteristic stress was explained from the perspective of a meso-mechanical mechanism. From the inversion results of the acoustic emission (AE) moment tensor, it was found that the proportion of tensile cracks gradually increased with the increase in the initial damage of the rock in the stable and unsteady stages of the rock crack propagation.

Keywords

• freeze–thaw damage
• fracture process
• acoustic emission
• signal processing
• AE moment tensor