Translational slip failures on slope incorporating unsaturated soil mechanics

Many slopes experienced shallow translational slips due to rainwater infiltration. Infinite slope model has been widely used for such landslides in past decades. It is widely stated that infinite slope analysis is valid when the depth of the sliding mass is much smaller than its length, but how the depth/length ratio influences the accuracy of analysis was rarely investigated in the literature. By comparing the factor of safety obtained by infinite slope analysis and finite element analysis to slopes of finite length and with real boundary conditions, the influence of depth/length ratio on the accuracy of infinite slope analysis is investigated. The error caused by infinite slope analysis is found to be highly linear with respect to the depth/length ratio of the failing mass. It is important to consider the depth/length ratio in order to check the accuracy of the infinite slope model in translational slip analysis.