Stability analysis of vegetated slopes under steady transpiration state considering tensile strength cut-off

Abstract

Abstract Vegetation is natural and eco-friendly material for slope reinforcement. To simple and effective analysis of vegetated slopes, this study proposes a novel approach considering the tensile strength cut-off criterion (C-F criterion) of unsaturated root-soil composites. The proposed method incorporates the hydrological and mechanical effects of vegetation roots. A 1D stability model is developed to compute the safety factors of vegetated slopes under steady transpiration state. Parametric studies are performed to investigate the effects of shrub root depth, slope angle, rainfall intensity, transpiration rate, and tensile strength on pore-water pressure (uw) and slope safety factors (Fs), which are computed using both the C-F criterion and the Fredlund strength criterion. The results demonstrate that Fs and uw decreases with increasing slope angle and rainfall intensity. Slope angle and rainfall intensity of vegetated slopes has an adverse effects on the slope stability. Moreover, Fs increases with increasing tensile strength. Furthermore, the transpiration rate and root depth increases, Fs and uw increases. Root depth, tensile strength, and transpiration rate are favorable for slope stability, while slope angle and rainfall are unfavorable. Shallow slopes are more sensitive to rainfall than deep slopes. In the soil layer with roots, Fs for unsaturated vegetation slopes with tensile strength cut-off are reduced compared to those based on the Fredlund strength equation. The C-F criterion is best suited for evaluating the shallow slope stability. Overall, the proposed method offers a simple and practical approach to assess the vegetated slopes stability.