Stability analysis of two-dimensional excavated slopes considering strength anisotropy

Using the finite element method, a cohesive horizontal ground is sequentially excavated until the stress state along a potential slip surface of the excavated slope reaches the critical state. Mobilized friction angle and stress ratio contours in the slope generated by the finite element solution are examined to quantify the part of the slip surface that undergoes extension resulting in anisotropic conditions. The effects of factors such as excavation depths, drainage boundary conditions, slope angles, and initial stress conditions on slope stability are investigated. It is shown that excavated slopes display anisotropic behavior and that the consideration of strength anisotropy in slope stability analysis is essential. For the example considered, it was found that the extent of the extension zone of the slip surface increases as the slope angle decreases and that this relationship is linear.