Stability Analysis Models of Vegetative Slopes: A Review

Vegetative slope protection is a technique that stabilizes slopes and beautifies the ecological environment. Vegetation improves the environment, and its deeper and shallower roots anchor and reinforce the soil mantle, respectively. The root, as a natural reinforce material, contributes to the cohesion of soil and increase the weight of the vegetative slope, which complicates the slope stability analysis models. The cohesion affected by root system is estimated by the additional cohesion item in the Mohr–Coulomb equation based on the stress of root system or the friction between surrounding soil and roots. In certain circumstances, the root is seen as a fibre that provides the additional cohesion. Roots also affect the soil moisture by intercepting rainfall and absorbing water, which affects the stability. Many methods can be used to describe the change of root characteristics, analyse the long-term stability of vegetative slopes and predict the deformation of vegetative slopes. This paper summarizes some previous stability analysis models of vegetative slopes. It shows that the root distribution which determines the root range and reforms the structure of vegetative slopes is ambiguous in previous studies. The change of soil characteristics induced by roots need to be further explored. The most crucial issue for the stability analysis modelling of vegetative slopes is the way to describe the distribution variation of root systems and its relationship with slope stability.