Analysis of plant root-induced preferential flow and pore water pressure variation by a dual-permeability model

There is a lack of numerical study on how planting density affects soil pore water pressure and shear strength during heavy rainfall. This study aims to investigate the impact of plant root-induced preferential flow on hydro-mechanical processes of vegetated soils under different planting densities. Two modelling approaches, namely single- and dual-permeability models, were integrated with an infinite slope stability approach to simulate pore water pressure dynamics and slope stability. Laboratory tests on soils with two different planting densities for a plant species, Schefflera heptaphylla, were conducted for numerical simulations. The single-permeability model overestimated the pore water pressure in shallow soil and underestimated the infiltration depth. The dual-permeability model, which is able to model the effects of preferential flow, can better capture the observations of rapid increase of pore water pressure and deeper pressure response in the vegetated soil. However, caution should be taken on the choice of pore water pressure when using the dual-permeability model to assess the factor of safety. The dual-permeability model using the pore water pressure in the preferential flow domain and that in the matrix domain would result in lower and higher factor of safety, respectively.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author