Study on the Catastrophic Evolution of Tianshan Road Slope under the Freeze-Thaw Cycles

The maximum temperature difference of Tianshan Road can reach 77.4°C in a year. Under such complex mechanical environment, the mechanical properties of rock mass and structural planes will change significantly as the increase of freeze-thaw cycles (FTC). Consequently, the FTC has become a key factor in the instability and failure of rocky slopes along the Tianshan Road. In this paper, the progressive deformation of rocky slopes and sudden failure process after critical instability were studied through the FTC tests of rock mass and structural planes, discrete element method, and theoretical analysis. The results show that the structural planes and internal microcracks of the rock mass expand under the action of the FTC, causing a gradual decrease in the stability of the slope. The dynamic collapse of the rocky slope has a certain degree of randomness caused by the spatial distribution of structural planes and the interaction between the rock fragments. Due to the limitation of the slipping space and the tilt angle of the trailing edge of the slope, long-distance migration did not occur, and the in situ accumulation of the slope was obvious after failure. The analysis method in this paper can provide an important reference for guiding the catastrophe mechanism analysis and protection of engineering slopes in cold regions.