Comparison of Three Procedures for Evaluating Earthquake-Induced Soil Liquefaction

Over the past decade, major advances have occurred in both the understanding and the practice with regard to the evaluation of soil liquefaction potential during earthquakes. Among these advances, there are two analytical frameworks (i.e., Seed et al. (2003) and Idriss and Boulanger (2008) procedures), which are widely accepted by the industry. The most significant achievement of the new procedures is their new criteria for assessment of liquefaction potential of low-plasticity silts and clays. These two new procedures are changing the way the design and regulatory communities consider soil liquefaction evaluation and may likely become standard-ofpractice in the near future. This paper relates these two new procedures with the Youd et al. (2001) procedures by comparing the cyclic resistance ratio (CRR), the factor of safety (FS) against liquefaction, and the post-earthquake reconsolidation settlement (Δ ) at different depths using both Standard Penetration Test (SPT)-based and Cone Penetration Test (CPT)-based methods. In addition, paired SPTs and CPTs are used to evaluate the relative performance between the SPT-based and the CPT-based correlations for each of these three procedures. Assessments of conservatism are made not only for the three analytical frameworks but also for correlations between SPT and CPT data. Discussions and recommendations oriented for practitioners are made on some components of each analytical framework