Effect of Freeze-Thaw on the Mechanical Properties of Semi-penetrating Single Fractured Sandstone Samples

Rock slopes in high-altitude cold regions are prone to failure after being subjected to freeze–thaw cycles, which may be attributed to the weakening of rock strength caused by long-term freeze–thaw action. To investigate the influence of freeze–thaw cycles on the mechanical properties of sandstone, triaxial compression tests were conducted on semi-penetrating single-fractured sandstone samples with three fracture inclination angles (15°, 30°, and 45°) under different freeze–thaw cycles (0, 5, and 10 cycles). The confining pressures were set to 50, 200, and 400 kPa, respectively. The test results indicate that semi-penetrating fractured sandstone samples with different inclination angles exhibit strain-softening behavior under different freeze–thaw cycles, and the volumetric deformation shows a process of initial contraction followed by dilation. Freeze–thaw action has a significant influence on the strength of the sandstone samples. With the increase in the number of freeze–thaw cycles, the strength of the semi-penetrating single-fractured sandstone samples gradually decreases. In addition, as the inclination angle of the semi-penetrating fracture increases, the strength of the sandstone samples shows a decreasing trend.