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.
Highlights
Published: 15 October 2021With the expansion of economic activities around the world, rock stability problems in projects such as railway construction, tunnel excavation, resource extraction, and slope treatment in cold regions have become an urgent problem to be solved [1,2,3,4]
We quantitatively investigated the relationship between the initial damage DNT caused by freeze–thaw cycles and the number of freeze–thaw cycles by measuring the P-wave velocity
In order to study the effect of the number of cycles and the lowest freeze–thaw temperature on the P-wave velocity and damage after freezing and thawing, the P-wave velocity was measured after every 5 cycles, and the P-wave velocity at each freeze–thaw temperature was measured after 20 freeze–thaw cycles
Summary
With the expansion of economic activities around the world, rock stability problems in projects such as railway construction, tunnel excavation, resource extraction, and slope treatment in cold regions have become an urgent problem to be solved [1,2,3,4] For this reason, many scholars have carried out a series of studies on the deformation and failure characteristics of rocks under freezing and thawing conditions in cold regions. The mechanical response of the rock during the loading process can be regarded as the coupling effect of the initial damage caused by freeze–thaw cycles and the damage caused by the increased stress. Conducting indoor experiments to study the AE characteristics during the process of rock damage and fracture under freezing and thawing environments is of great significance for the stability prediction of rock engineering in cold regions. AE technology was used to monitor the rock fracture information for each sandstone sample after the freeze–thaw treatment to provide a theoretical basis for judging the damage and fracture of the rock in an actual engineering application
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