Stratified slopes, numerical and empirical stability analysis

Urbanisation means that many natural slopes in and around cities are often subjected to cuts resulting in dramatic changes in the geometry of slope faces mostly by increasing slope angle, which could lead to failures with catastrophic consequences. As most natural slopes are of non-homogeneous layered nature, understanding the stability behaviour of such slopes will be of utmost importance. The current practice in analysing slopes of complicated nature, geometrically and materially, is mostly to apply simplifications sacrificing accuracy leading to use of large factors of safety (FoS), which could undermine analytical and economic feasibility of projects. In this research study, limit-equilibrium and finite-element methods are used by the Oasys slope and Plaxis 2D software programs, respectively, empirically and numerically to model and analyse geometrically non-homogeneous stratified slopes with the aim of understanding the effects of non-homogeneity of geometry and materials on stability under various inclination angles of slope face. The analysis included determination of FoS as well as a sensitivity analysis looking into the combined effects of contributing parameters.