Effect of 3D geometric variation on slope stability for sandy slopes

ABSTRACT The aim of this study is to assess the influence of 3D geometric variation on slope stability and to compare with the corresponding 2D analysis results. Homogeneous sand slopes with four slope geometries, namely, normal surfaces, curved surfaces, turning corners and turning arcs of various angles and slope inclinations, were analysed using PLAXIS LE. The 3D results demonstrated that the factor of safety of curved surface slopes will decrease with increasing concave curvature. For turning corner slopes, an increase in the concavity resulted in an increase in stability. When comparing the 3D and 2D results, the analysis showed that while most of the 2D analysis results yield a lower factor of safety than that of a 3D analysis, there were various concave slopes in which a 3D analysis was more conservative. The study also demonstrated that a 3D analysis is beneficial to capture slope failures spreading across the sloped surface, which can be used by practitioners to design more cost-effective stabilization measures.