RELIABILITY APPLIED TO SLOPE STABILITY ANALYSIS

Formally probabilistic methods for the analysis of slope stability hav e had relatively little impact on practice. Many engineers are net fam iliar with probabilistic concepts, and it has been difficult to incorp orate concepts of reliability into practice. Also, there is confusion over what reliability and probability of failure mean. The most effect ive applications of probabilistic methods are those involving relative probabilities of failure or illuminating the effects of uncertainties in the parameters. Attempts to determine the absolute probability of failure are much less successful. The paper describes how probabilisti c descriptions of soil parameters can be derived from field and labora tory data and applied in stability analysis. The first-order. second-m oment approach is explored and applied to the design of embankment dam s. The example illustrates the relative contributions of uncertainties about different parameters to the reliability of the embankment. Reli ability analysis is especially useful in establishing design values of factors of safety representing consistent risks for different types o f failure.