Analytical solutions of pore-water pressure distributions in a vegetated multi-layered slope considering the effects of roots on water permeability

New analytical solutions of pore-water pressure (PWP) distributions in a vegetated multi-layered slope are derived considering the effects of roots on water permeability. PWP distributions are significantly affected by root-induced reductions in water permeability due to increases in the root volume ratio (Rv). Under drying conditions, negative PWP increases with Rv. The negative PWP induced by root water uptake increases with the desaturation coefficient (αi) or the ratio of the transpiration rate to saturated water permeability (Tp/ksi). As the overall water permeability underneath the vegetation layer decreases, the negative PWP induced by root water uptake increases.