Arid Zone Research ›› 2025, Vol. 42 ›› Issue (10): 1841-1850.doi: 10.13866/j.azr.2025.10.08

• Land and Water Resources • Previous Articles     Next Articles

Effects of freeze-thaw cycles on shear characteristics and microstructure of alpine meadow soil in riparian zone

XU Pengkai1(), ZHU Haili1,2(), LI Benfeng3, ZHANG Hailong1, WU Yuechen1, HONG Chenze1, LIU Yabin1,2, LI Guorong1,2   

  1. 1. Department of Geological Engineering, Qinghai University, Xining 810016, Qinghai, China
    2. Laboratory of Cenozoic Resources and Environment on the Northern Margin of the Qinghai-Tibet Plateau, Xining 810016, Qinghai, China
    3. Qinghai Traffic Engineering Consulting Co., Ltd., Xining 810016, Qinghai, China
  • Received:2025-03-01 Revised:2025-05-31 Online:2025-10-15 Published:2025-10-22
  • Contact: ZHU Haili E-mail:pengkaixu666@163.com;qdzhuhaili@163.com

Abstract:

The mechanical properties of root-influenced soil on the meandering riverbank in the source region of the Yellow River under freeze-thaw cycles directly affect its stability and lateral evolution. Using triaxial shear tests performed on root-influenced soil with a root content of 7% under freeze-thaw cycles, in combination with microstructural analysis, this study investigated the evolution law of the shear resistance characteristics of the soil in the alpine meadow riverbank zone in the source region of the Yellow River under freeze-thaw cycles and explored the regulatory mechanism of the meadow root system. The results showed that after 15 freeze-thaw cycles, the soil mechanical properties deteriorated significantly. In root-free soil, the difference of principal stress decreased by 30.67%, cohesion decreased by 25.47%, and porosity increased by 20.02%. In contrast, in root-influenced soil, the difference of principal stress decreased by only 28%, cohesion decreased by 5.8%, and porosity increased by<10%. Microscopic analysis showed that the root system constrains the fragmentation and migration of particles through reinforcement and inhibits the expansion of pores through the anchoring effect, thereby reducing freeze-thaw damage. The findings reveal the mechanism by which plant roots enhance the freeze-thaw resistance of soil, thus providing a theoretical basis for the ecological restoration and stability maintenance of riverbank zones in cold regions.

Key words: source region of the Yellow River, freeze-thaw cycle, shear strength, rooted soil, microstructure