Abstract: To investigate the mechanical properties of coarse-grained soils in the Tianshan region of Xinjiang under freeze-thaw cycles and varying coarse-grain content, a series of unconsolidated undrained triaxial tests were conducted. The study focused on stress-strain curves, elastic modulus, compressive strength, and shear strength, examining their variations under different conditions. The experimental results indicate that: (1)Under the same confining pressure, the stress-strain curve morphology is not significantly affected by the number of freeze-thaw cycles, exhibiting weak strain-hardening behavior. However, deviatoric stress shows varying degrees of attenuation under different freeze-thaw cycles. After 7 to 10 cycles, deviatoric stress tends to recover with further cycles. Additionally, increasing coarse-grain content transforms the stress-strain curve from weak strain hardening to strong strain hardening. (2)The elastic modulus initially decreases during the freeze-thaw process and then stabilizes. With increasing coarse-grain content, the elastic modulus first increases and then decreases. (3)Compressive strength initially decreases and then stabilizes with freeze-thaw cycles, while it gradually increases and then stabilizes with increasing coarse-grain content. (4)Cohesion initially decreases with freeze-thaw cycles and then stabilizes, showing a positive correlation with coarse-grain content. (5)The internal friction angle first decreases and then increases with freeze-thaw cycles, while it exhibits a more complex trend with increasing coarse-grain content. Freeze-thaw damage is cumulative, with the first cycle having the greatest impact. These findings provide reference data for analyzing the stability of coarse-grained soil slopes in high-altitude cold regions of Xinjiang.