黄河源区曲流河岸有根土在冻融作用下的力学特性直接影响其稳定性与横向演变。通过开展含根量为7%的有根土在冻融条件下的三轴剪切试验，结合微观结构分析，研究了黄河源区高寒草甸河岸带土体在冻融作用下的抗剪特性演变规律，并探讨了草甸根系的调控机制。结果表明：冻融循环15次后土体力学性能显著劣化，无根土主应力差下降30.67%，黏聚力下降25.47%，孔隙率增加20.02%，而有根土主应力差下降仅28%，黏聚力下降5.8%，孔隙率增幅不足10%。微观分析表明，根系通过加筋作用约束颗粒破碎与迁移，并通过锚固效应抑制孔隙扩张，从而减缓冻融损伤。研究揭示了植物根系对土体抗冻融能力的增强机制，为寒区河岸带生态修复与稳定性维护提供了理论依据。

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.