Seismic Slope Stability

Developments in the procedures for evaluating the seismic response and safety of slopes over the last 25 years are reviewed. There have been five major developments since 1988 when the first review was reported by Finn. First is the broad acceptance of FLAC as a standard computational platform for static and dynamic analysis in geotechnical engineering. Second is the use of displacement as a performance criterion for assessing the seismic performance of slopes and embankment dams and planning cost effective remedial measures, especially when there is a potential for liquefaction in the dam itself or in the foundation. The third development is the use of centrifuge tests on model structures to validate methods of analysis and the associated constitutive models. Fourth is the emergence of seismic risk and reliability analysis as an aid to determining the dominant failure modes of the dam, the probability of occurrence of unacceptable damage, and the associated probabilities of both economic losses and loss of life. The fifth development is the contribution of major fundamental research programs to significant elements of seismic safety of slopes such as evaluation of liquefaction potential, determination of residual strength, handling probabilistic ground motions in design and the calibration of constitutive models using appropriate laboratory tests. These developments and their impact on engineering practice are illustrated by appropriate case histories.