Impact of the Spatial Variability of Soil Shear Strength on the Stability of an Undrained Clay Slope

Random fields have been a widely applied method to describe the inherent spatial variability of soil properties, but the correlation structures used in random fields are mainly concentrated on isotropy or transverse anisotropy. This paper attempts to investigate the influence of the spatial variability of the undrained shear strength on slope stability for a two-dimensional rotated anisotropy correlation structure. The rotated anisotropy random fields are simulated using the covariance matrix decomposition method. Within Monte-Carlo framework, sensitivity studies are performed to explore the effects of the rotation angle under the exponential correlation structure on the slope reliability and failure mechanism. The quantified classification for three types of failure mechanisms, namely face failure, toe failure and base failure, is suggested using the failure depth. The results indicate that the rotation angle shows a dual effect on the reliability of slope in comparison to the case transverse anisotropy. This study can improve our understanding of the effect of a rotated anisotropy correlation structure on slope stability.

Keywords: Slope stability, random field, anisotropy, failure mechanism.