A Consistent Correlation between V _s , SPT, and CPT Metrics for Use in Liquefaction Evaluation Procedures

Abstract

The objective of this study is to develop a consistent relationship between small strain shear wave velocity (Vs), corrected cone penetration test (CPT) tip resistance (qc1Ncs), and corrected standard penetration test (SPT) blow count (N1,60cs) for liquefiable soils. In the absence of actual measurements of Vs in the field, it is common to use data from SPT or CPT testing to estimate Vs. However, empirical correlations between pairs of these in situ metrics can yield significantly different values of Vs. Using recent correlations between cyclic resistance ratio normalized to M7.5 (CRRM7.5) and Vs normalized to one atmosphere of overburden (Vs1), qc1Ncs, or N1,60cs, a consistent relationship is developed such that reasonably similar values of Vs can be obtained using either qc1Ncs or N1,60cs. In comparison to two published Vs correlations, the correlations given in this study provide an average Vs value when using N1,60cs as the dependent variable but a slightly lower prediction of Vs when using qc1Ncs as the dependent variable.