Uncertainty in Back Analysis of Slopes: Kettleman Hills Case History

Abstract

A theoretical approach is described for back analysis to determine shear strengths from slope failures. This approach systematically accounts for uncertainties encountered in practice, including uncertainties in empirical information, laboratory test results, field measurements, and the slope stability model used in the back analysis. The approach is applied to a slope failure in the Kettleman Hills landfill to demonstrate its use. Insight is gained from this case history concerning uncertainties in (1) calculated factors of safety from two-dimensional, limit equilibrium methods and (2) mobilized strengths in strain-softening materials.