[1]Zhan Peng,Zhang Chaobo,Zhang Qiang,et al.Effects of Alfalfa Roots on the Shear Properties of Loess Under Alternate Drying-Wetting Conditions[J].Research of Soil and Water Conservation,2023,30(06):222-230.[doi:10.13869/j.cnki.rswc.2023.06.006]
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Effects of Alfalfa Roots on the Shear Properties of Loess Under Alternate Drying-Wetting Conditions
Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
30
Number of periods:
2023 06
Page number:
222-230
Column:
Public date:
2023-10-10
- Title:
- Effects of Alfalfa Roots on the Shear Properties of Loess Under Alternate Drying-Wetting Conditions
- CLC:
- S157.2
- DOI:
- 10.13869/j.cnki.rswc.2023.06.006
- Abstract:
- [Objective] The aim of this study is to explore the influence of plant roots on shear properties of loess under alternate drying-wetting conditions and provide a theoretical basis for the ecological construction and engineering construction in the loess region under the state of alternate drying-wetting. [Methods] Direct shear test in laboratory was conducted on loess samples with/without alfalfa roots to study the relationship between shear properties of loess and influencing factors including alternate drying-wetting, root size(root length, root diameter), soil bulk density and water content, and to evaluate the reinforcement of roots on shear resistance of loess based on the Wu model. [Results] The surface of root-soil composite became rough, loose and easy to fall off after alternate drying-wetting, and uneven cracks appeared. The shear indexes of the composite decreased after alternate drying-wetting. Root size significantly affected the shear behavior of root-soil composite under alternate drying-wetting conditions. Longer and larger roots resulted in greater soil shear strength. Soil cohesion and internal friction angle were positively correlated with soil bulk density in a certain range, and they decreased after alternate drying-wetting. Under the same alternate drying-wetting condition, the cohesion first increased and then decreased with soil water content. At the same level of soil water content, shear strength was weaker in soil under alternate drying-wetting than in soil without alternate drying-wetting. The limitations of the Wu model led to the relatively wide difference between the results by the model and the values by the shear tests. The estimation results of root cohesion by Wu model could be optimized by replacing root tensile strength with root pullout strength. [Conclusion] Under alternate drying-wetting conditions, the size of plant roots, soil bulk density, and soil moisture content all have a certain impact on the shear resistance of loess.
- References:
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Last Update:
2023-10-10