Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Soil shear resistance in the Riparian zone directly affects riverbank stability. Furthermore, theinfluence of freezing and thawing on the structure and mechanical properties of alpine meadow soils is directlyrelated to the collapse frequency and lateral migration of the river bank in the source region of the Yellow River.To investigate the change rules and generation mechanisms of the root bearing soil mass, the shear strength indexin the meandering Riparian zone of the source region of the Yellow River under the effects of freezing andthawing were assessed. The subsequent impacts of different root contents on the soil mass shear strength indexwere also determined using an indoor freeze-thaw direct shear test with remolded soil. The experimental resultsshow that plant roots can significantly and increasingly enhance soil cohesion, which can range from 2.7% to77.9%. Variations in the internal friction angle with root content were not significant. The freeze- thaw cycleweakens soil cohesion, especially in the early stages. The maximum decrease in cohesion of 19.0% occurred withthree freeze- thaw cycles, after which the changes stabilized, while the internal friction angle showed a slightincreasing trend. The effects of the freeze-thaw action on the shear strength index of the rooted soil is smallerthan that of the plain soil. Under the same freeze- thaw frequency conditions, the decrease in cohesion of therooted samples was found to be smaller than that of the plain soil samples. The root systems of meadow plantscan block the changes in soil temperature, reduce the decrease in soil cohesion, and increase with the rootcontent. When the root content reaches 11%, its weakening effect on soil cohesion is 4.2%-27.7% less than thatof plain soil. The Riparian zone, as the source area of the Yellow River, should strengthen the protection ofriverside meadow vegetation, maximize the role of the root system in enhancing Riparian stability, and protectriver ecology.
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