Evaluating the effect of slope curvature on slope stability by a numerical analysis

This paper investigates, using three-dimensional numerical modelling, the stability of curvature-based nine general hillslope types created by combining three profile and three lateral curvatures. The results show that the hillslopes with a concave profile curvature possess the highest pore-water pressure along the axial line, and hillslopes with a convex profile curvature generate the smallest pore-water pressure along the line. The results also show that the profile curvature dominates the pore-water pressure along the axial line, and the effect of lateral curvature is minimal. Displacement shapes are generally the opposite of lateral curvature shapes for hillslopes with convex and concave lateral curvatures, whereas they are parallel to the bed for the slopes with straight lateral curvatures. Even though the rainfall amount and duration are equal, the fully saturated volume and average saturation of hillslope are significantly different. Concave-profile types of hillslope possess a larger volume of fully saturated area than others possessing larger deformations. This indicates that the hillslopes with concave profile curvatures are susceptible to mud and debris flows. These slopes also show a possibility of greater run-out distances, as their X-displacements are higher than others. Calculation of the Factor of Safety indicates that hillslopes with straight-profile curvatures are more stable. Increase in curvature in either direction is the most significant factor in decreasing the overall stability of a hillslope.