Probabilistic slope stability analysis for practice

Abstract

The impact of uncertainty on the reliability of slope design and performance assessment is often significant. Conventional slope practice based on the factor of safety cannot explicitly address uncertainty, thus compromising the adequacy of projections. Probabilistic techniques are rational means to quantify and incorporate uncertainty into slope analysis and design. A spreadsheet approach for probabilistic slope stability analysis is developed. The methodology is based on Monte Carlo simulation using the familiar and readily available software, Microsoft® Excel 97 and @Risk. The analysis accounts for the spatial variability of the input variables, the statistical uncertainty due to limited data, and biases in the empirical factors and correlations used. The approach is simple and can be applied in practice with little effort beyond that needed in a conventional analysis. The methodology is illustrated by a probabilistic slope analysis of the dykes of the James Bay hydroelectric project. The results are compared with those obtained using the first-order second-moment method, and the practical insights gained through the analysis are highlighted. The deficiencies of a simpler probabilistic analysis are illustrated. Key words: probabilistic analysis, slope stability, Monte Carlo simulation, spatial variability.

Comparison of Different Standards Based on Computing the Probability of Failure of Flood Protection Dikes

“…Conventional slope practice based on the factor of safety cannot explicitly address uncertainty [33]. Practicing engineers and researchers have been concerned with the interpretation of safety for a long time.…”

Uncertainty assessment of critical excavation depth of vertical unsupported cuts in undrained clay using random eld theorem

“…Although most traditional limit equilibrium methods do not consider spatial variability, some investigators have combined LEM with random eld theory (e.g., [28][29][30][31][32][33][34][35][36][37]). However, the inherent nature of LEM is that it leads to a critical failure surface which in 2-D analysis appears as a straight line or curvilinear shape that could be noncircular.…”

Epistemic uncertainties and natural hazard risk assessment. 1. A review of different natural hazard areas

“…Although spatial variability of soil properties has been recognised as an important source of epistemic uncertainty in the literature (e.g. El-Ramly et al, 2002;Griffiths and Fenton, 2004), it has often been ignored in previous analyses using limit equilibrium methods. The use of constant values for soil properties over soil deposits may lead to unreliable estimates of the probability 15 of failure of a slope (El-Ramly et al, 2002;Griffiths and Fenton, 2004;Cho, 2007;Griffiths et al, 2009).…”