Analysis of the stability of slopes reinforced by roots

This paper deals with the assessment of vegetation contribution to slope stability, with particular emphasis on the mechanical effects provided by the root system. As is well known the presence of roots within the soil increases, with respect to the case of soil without vegetation, the material effective cohesion with no significant change in its friction angle. Such mechanical effect can be introduced in the Mohr-Coulomb failure law through an "apparent cohesion" term, which adds to the soil effective cohesion. The contribution of root reinforcement to the soil shear strength has been investigated in slope stability finite element analyses, modifying the soil properties of individual slope elements including vegetation. This approach allowed quantification of the effect of the mechanical root reinforcement on the slope factor of safety and assessment of the sensitivity of slope stability to the variation of apparent cohesion and root zone depth assumed in the numerical simulations. © 2010 WIT Press.