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

Abstract

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.

Orthogonal experimental study on the compressibility characteristics of bank sandy silt based on freeze-thaw effects

“…The number of F-T cycles is closely related to the mechanical characteristics of the soil. Existing studies indicate that F-T actions can disrupt soil structure, leading to alterations in soil mechanical properties [ 9 , 10 ]; Qiu et al [ 11 ], through uniaxial compression tests on moraine soils, with varying F-T cycles, rock content, and water content, discovered a continuous reduction in the mechanical strength of the soil post-thaw. Furthermore, the rate of reduction was fastest at the optimal water content.…”

Study on the Unified Mechanical Properties of Ili Undisturbed Loess under the Influence of Soluble Salt

“…[22][23][24][25][26][27]. At present, there are many studies on the loess in the monsoon area in the reports [28][29][30][31], and the research on Ili loess mainly focuses on the mechanical properties under cycling test conditions of dry-wet [32,33] and freeze-thaw [34,35], respectively. However, there are few studies on the mechanical properties of Ili loess under the change of soluble salt content.…”