Numerical modelling of rainfall-induced instability of vegetated slopes

Vegetation is known to play an important role in reducing landslide hazard. This paper presents a numerical model, which allows modelling of rainfall-induced instabilities of vegetated slopes. Both the mechanical reinforcement and the water uptake by plant roots are taken into account by considering a coupled mechanical-hydrological system. A modified Cam-Clay model for unsaturated soil is used. The mechanical reinforcement of roots is simulated by its contribution to the preconsolidation pressure. The water uptake is modelled by a sink term for variably saturated flow. The numerical model is implemented in two finite-element codes for two- and three-dimensional problems. The model performance is demonstrated by two numerical examples.