Three-dimensional dynamic stability analysis of vegetation-rooted slopes

In this study, an analytical model for the three-dimensional (3D) dynamic stability analysis of vegetation-rooted slopes is first developed under steady-state unsaturated flow conditions. Root reinforcement, defined as the increase in the soil shear strength produced by the mechanical and hydrological effects of vegetation roots, is included in the proposed analytical model. By combining the modified pseudo-dynamic approach (MPDA) and the kinematic theory of limit analysis to the 3D discretized failure model, the most critical failure surface and the corresponding factor of safety (FS) are derived to examine the stability of vegetation-rooted slopes with the aid of the optimization algorithm of particle swarm. The proposed approach is verified by comparing with published analytical solutions and numerical results. A series of parametric analysis are then conducted to examine the influence of seismic-related parameters, vegetation properties, possible surcharge and slope geometry parameters on the slope stability. Finally, a comparison between the slope stability under different root architectures is provided and discussed. The results show that, for these selected cases, the stability of vegetation-rooted slopes is significantly improved by approximately 45% compared to bare soil slopes, and the divergences of reinforcement effects between different root architectures can be negligible.