Evaluating Calculated Risk in Geotechnical Engineering

Recent years have seen rapidly growing research into applied probability and increased interest in applications to geotechnical engineering practice. Unfortunately, probability still remains a mystery to many engineers, partly because of a language barrier and partly from lack of examples showing how the methodology can be used in the decision‐making process. The following types of applications are described and illustrated in general terms: separating systematic and random errors when evaluating uncertainty in the stability of slopes; safety factors in connection with analysis of liquefaction; optimizing the design of an embankment in the face of uncertainty concerning stability; risk evaluation for an industrial facility built over potentially liquefiable soils; and risk evaluation for earth dams. Even when a precise quantification of probability of failure is not possible, systematic formulation of an analysis aids greatly in understanding the major sources of risk and thus points the way for costeffective remedial measures. Analyses of reliability and risk are potentially most valuable during the early stages of a project in guiding the decision as to whether or not to proceed and in helping to establish design criteria.