Water-salt migration and strength characteristics of fine-grained salinized aeolian sand under freeze-thaw cycles

Freeze-thaw cycles significantly deteriorate the engineering properties of fine-grained salinized aeolian sand, resulting in a decrease in the long-term performance of aeolian sand roadbeds and frequent roadbed diseases. To analyze the influence of fine content on the water-salt migration and strength characteristics of salinized aeolian sand at the edge of deserts under freeze-thaw cycles. A self-designed freeze-thaw cycle device was used to conduct water-salt migration tests on salinized aeolian sand with different fines content. A series of direct shear tests was conducted on soil samples before and after freeze-thaw cycles. The distribution of temperature field, the migration of water and salt, and the strength change before and after freeze-thaw cycles were obtained. The test results show that under the freeze-thaw condition, the temperature of salinized aeolian sand with different fines content showed a fluctuation with time, and the fluctuation amplitude decreased with the increase of depth. As fines content increased, the minimum soil temperature rose, while both unfrozen and total water contents decreased. The peak conductivity decreases and then increases, and the salt content continues to increase. Prior to freeze-thaw cycling, the shear strength of salinized aeolian sand under different vertical pressures increased with the increase of fines content, and after that, the shear strength of salinized aeolian sand with different fines content decreased significantly. The higher the fine content, the more obvious the deterioration of its shear strength. This study can provide theoretical guidance for road construction in salinized aeolian sand area.