Damage characteristics of shear strength of joints under freeze-thaw cycles

The freeze-thaw cycles and joint will deteriorate the strength characteristics of jointed rock mass and may lead to geotechnical failures in cold regions. Former studies mainly focus on the effect of freeze-thaw conditions on the mechanical properties of rock. However, for rock engineering, rock joints are ubiquitous in rock mass engineering, and the water in rock joints will experience freeze-thaw process when temperature varies alternatively. The frost heaving pressure generated during this process causes the joints to propagate and hence will eventually leads to the failure of rock masses. However, few researches focus on the degradation of strength characteristics of rock joints under freeze-thaw cycles, especially for joint damage evolution mechanism of shear strength characteristics, which is actually crucial factor for rock masses stability. Therefore, in this paper, a large number of shear experiments were conducted to investigate the influence of freeze-thaw cycle-induced joint shearing degradation on cohesion as well as friction angle of joints with considering joint persistency values. Based on the damage mechanics, together with the experimental results, the damage variables of shear strength parameters under freezing-thawing cycles are analyzed. In addition, a damage evolution model for joint shearing under freeze-thaw cycles is established with considering freeze-thaw cycles as well as joint persistency, and the feasibility and capability of this proposed model are then further verified both experimentally and theoretically.

Automated summary

This study investigates the influence of freeze-thaw cycle-induced joint shearing degradation on the strength characteristics of rock joints and establishes a damage evolution model to analyze the process.