Abstract
The Green–Ampt (GA) model is widely applied in practice because of its simplicity and relatively few parameters. However, the GA model and its modifications are mostly only suitable for uniform rainfall, and rarely account for the effect of water uptake by vegetation roots. In this study, a modified GA model that accounts for both roots and moisture redistribution is proposed to assess slope stability. Compared with the numerical solution, the modified GA model slightly overestimates the wetting front depth and underestimates the moisture content of surface soil. The hydrological and mechanical effects of vegetation roots on slope stability are also incorporated in the proposed model. Parametric analyses are performed to investigate the effects of parameters including rainfall intensity on the safety factor (Fs). The results show that the wetting front depth decreases/increases with the increase of slope angle/rainfall intensity, and Fs of the slope decreases with the increase of slope angle and rainfall intensity. The safety factor of the slope is negatively correlated with rainfall duration and initial moisture content. Exponential and triangular roots have more significant effect on reinforcing shallow soils than uniform roots. The safety factor of the shrub-covered slope is 1.45 times that of the bare slope. The proposed method has the advantages of simplicity and few parameters.
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Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Abbreviations
- q t :
-
Evaporation rate
- z r :
-
Root depth
- H :
-
Soil thickness
- β :
-
Slope angle
- k s :
-
Saturated permeability coefficient
- s f :
-
Suction head of the wetting front
- z f :
-
Wetting front depth
- t p :
-
Ponding water time
- θ s and θ i :
-
Saturated moisture content and initial moisture content
- θ r :
-
Residual moisture content
- ψ b :
-
Air entry pressure
- λ :
-
Pore distribution index
- c r :
-
Cohesion related to the vegetation roots
- c ′ and φ ′ :
-
Effective cohesion and the effective internal frictional angle
- φ b :
-
Angle of internal friction related to suction
- σ n :
-
Normal stress
- u w and u a :
-
Pore-water pressure and pore-air pressure
- ξ :
-
Correction factor
- T r :
-
Root tensile strength
- R f :
-
Root orientation factor
- RAR :
-
Root area ratio
- γ d and γ w :
-
Dry unit weights of soil and water
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Funding
We thank the National Natural Science Foundation of China (41790432) and the National Key Research and Development Program of China (No. 2021YFB2600026).
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Shaohong Li: Conceptualization, Code Developer, Writing—original draft. Peng Cui: Methodology, Formal analysis, Writing- original draft. Ping Cheng: Code Developer, Review & Editing. Lizhou Wu: Supervision, Methodology, Review & Editing.
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Li, S., Cui, P., Cheng, P. et al. Modified Green–Ampt Model Considering Vegetation Root Effect and Redistribution Characteristics for Slope Stability Analysis. Water Resour Manage 36, 2395–2410 (2022). https://doi.org/10.1007/s11269-022-03149-6
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DOI: https://doi.org/10.1007/s11269-022-03149-6