The Reliability of Long Undrained Slopes with Anisotropic Variability

The infinite slope equation serves as a useful tool for assessing the stability of long, shallow slopes. Alternatively, the finite-element method provides insights into long-slope failure mechanisms and deformation profiles. Both methods are suitable for probabilistic analyses that incorporate spatially variable soil properties. While the infinite slope equation considers variability solely perpendicular to the ground surface, finite-element simulations of long slopes can account for spatial variability in multiple directions. This paper presents the behavior of long slopes with anisotropic, spatially variable material properties compared with the one-dimensional infinite slope case. The random field correlation lengths that produce critical failure mechanisms and safety factors resembling the infinite slope are given particular attention, in addition to lateral correlation lengths that produce distinctly different failure mechanisms that do not fail along the full length of the slope. The influence of slope angle and the statistical distribution of shear strength parameters are further examined through parametric studies.