A comparative analysis of the stability of homogeneous and non-homogeneous soil slopes subject to various surcharge loading conditions

Slope stability is a topic of great importance within the scope of civil engineering, this study investigates the differences between homogeneous and non-homogenous soil slopes when various surcharge loading conditions are applied. To analyse slope stability the finite element method is used, this method uses the shear strength reduction method. This method gradually reduces the cohesion and friction angle of the soil until failure occurs in the model. Typically, the limit equilibrium method is used by civil engineers, which splits the model into slices to identify the failure mechanisms and the factor of safety. However, as the software improves, and the accuracy of analysis increases, finite element analysis will become the more commonly used method [1, 2]. In this study 6 different models are used in the analysis, three homogenous soil slopes and three nonhomogenous soil slopes to aid in the analysis, the soil properties were obtained from [3]. Each model was subject to surcharge loading, which was incrementally increased until failure occurred, recording the factor of safety at each point. The results gathered suggest that point loads caused failure in models to occur much quicker than surcharge loading from a uniformly distributed load, however, the failure area is much smaller. The comparison of homogenous and non-homogenous soil slopes shows that stability is dependent on three key properties including cohesion, unit weight, and friction angle, with the properties of the soil slope influencing the maximum surcharge loading that can be applied to a model. The results indicate that homogenous soils can withstand higher surcharge loading conditions compared to that of nonhomogenous soil slopes, except for homogenous models consisting of silty sand.