Stability analysis of the slopes composed of heterogeneous and anisotropic clay

It is well perceived that the shear strength properties of natural soil stratum are inherently anisotropic and spatially heterogeneous due to the depositional, geological and environmental factors. In this study, the concurrent effect of inherent anisotropy and spatial heterogeneity of undrained shear strength of clay on stability of sloped ground is examined by using a numerical lower bound limit analysis approach. The inherent anisotropy of the undrained shear strength of clay is incorporated into the numerical model by the application of an iterative process, and the random field technique is utilized to account for clay’s spatial variability. The numerical tool for slope’s safety factor determination is based on the combination of lower bound theory, finite element method, second-order conic optimization and the strength reduction method. Probabilistic analyses of slopes with/without external tractions showed a remarkable effect of concurrent consideration of anisotropy and heterogeneity of soil on the evaluated safety factor of slope.