Investigation of design parameters of a failed soil slope by back analysis

A soil slope instability occurred at the surface facility area of a mine site, which was successfully managed from occupational health and safety point of view, and no human or material loss was encountered. Three different excavation stages and consecutively occurring slope failures were investigated by back analysis. Limit equilibrium and finite element methods were employed for back analysis. The multiple failures enabled researchers to verify the parameters investigated by back analysis to be obtained from each failure. Extensive field and laboratory testing were available which constitutes a baseline for comparison. The performance of tests and several correlations proposed by other researchers were compared to the back analysis findings. The correlations that used the advantage of plasticity index and depth were found to be superior compared to the other test methods for this study. Moisture sensitivity, high groundwater level, and sampling are found to be some of the main reasons leading to soil slope failure.