Influence of Spatial Variability of Shear Strength Parameters on 3D Slope Reliability and Comparison of Analysis Methods

A 3D slope stability problem with spatially varying shear strength parameters has been analysed using the 3D random finite element method. This method links random fields of the random variables, in this case, cohesion and friction angle, with the finite element method within a Monte Carlo framework. The influence of spatial variability on calculated factors of safety and failure consequence has been investigated, and the results compared with a simpler 3D solution proposed by Vanmarcke. The simpler approach predicted a lower probability of failure under certain conditions, although, at high levels of anisotropy of the heterogeneity, the solutions converged. The reasons for the different solutions have been evaluated