Effect of Mica Content on Mechanical Properties of Yili River Valley Loess under the Impact of Freezing and Thawing

Natural disasters, including collapse, landslides, and debris flows, commonly occur in the Yili River Valley as a result of its distinctive terrain and climate. A large proportion of these are loess landslides. Hence, studying the mechanism of their occurrence is crucial. The loess in the Yili River Valley has a high mica content. By using freeze-thaw (FT) cycling tests, unconsolidated and undrained triaxial shear tests, and FT cycling experiments, the study clarifies the impact of mica content on the mechanical properties of the loess in the Yili River Valley under FT cycling conditions. The findings demonstrated that the loess's shear strength was negatively impacted by both the mica content and freeze-thaw cycles (FTCs). Under the same FT cycle conditions, the shear strength of the Yili Valley loess decreased with an increase in the mica content, particularly during the first ten cycles. Cohesion represented the impact of the mica content on the shear strength parameters. The cohesion decreases as the mica content increases. After ten cycles, the values of the cohesion tended to become stable, while the internal friction angle showed the opposite trend. For the same mica content, the shear strength of the Yili valley loess decreased with the increase in the number of FTCs, while the cohesion decreased, and the internal friction angle first increased and then decreased. The study's findings might offer a theoretical foundation for preventing and reducing loess landslides in the Yili River Valley caused by FTCs and high mica content.