Uncertainty in Steady‐State Liquefaction Evaluation Procedures

Abstract

The effects of uncertainty in the steady‐state procedure for evaluation of liquefaction potential are evaluated and discussed. While steady‐state concepts provide a useful framework for understanding of the liquefaction behavior of soils, it is quite sensitive to parameters whose magnitude are in practice uncertain. Density changes during sampling and the slope of the steady‐state line are identified as uncertain parameters. The uncertainty associated with those parameters is quantified by statistical analyses of previously reported data. The effect of these uncertainties on the results of the steady‐state liquefaction evaluation procedure is evaluated. The results indicate that, for many liquefiable soils, significant uncertainty exists in the steady‐state strength predicted by the steady‐state method. For such soils, this steady‐state strength must be significantly reduced in order to reduce the probability of misclassifying a liquefiable soil as a nonliquefiable soil to an acceptably low value. Reduction factors corresponding to various probabilities of misclassification are presented.