Study of the effect of soil anisotropy on slope stability using method of slices

Naturally occurring cohesive soil deposits are inherently anisotropic with respect to different properties amongst which is the shear strength. This anisotropy is primarily due to the process of sedimentation followed by predominantly one-dimensional consolidation. The effect of strength anisotropy on the stability of slopes has commonly been investigated using the mass procedure in which the mass of soil failed is taken as a one unit. The analysis is conducted by utilizing either the conventional limit equilibrium method or the upper bound technique of limit plasticity. It is, however, the method of slices that is most widely employed in the analysis of slope stability problems, especially with the advent of the digital computer. In this study, the influence of cohesion anisotropy on the stability of slopes in. homogeneous soil, with internal friction angle greater than zero, was investigated using the method of slices. Analysis was made for the case of two-dimensional circular slip surfaces. It has been found that soil anisotropy has a significant effect on the stability of slopes when the slope angle is less than 53 degrees. However, such an effect becomes insignificant as the soil angle of internal friction exceeds about 10 degrees. The results also indicated that the geometry of the slip surface is only slightly affected by the degree of anisotropy in the soil cohesion. (C) 2000 Elsevier Science Ltd. All rights reserved.