CPT-Based Probabilistic and Deterministic Assessment of In Situ Seismic Soil Liquefaction Potential

TLDR

The study develops a comprehensive CPT‑based methodology to assess seismic soil liquefaction potential, addressing normalization of resistance measurements for overburden stress and adjustment for thin liquefiable layers. The authors compiled global CPT liquefaction case histories, back‑analyzed them, and used Bayesian regression to derive probabilistic triggering correlations that incorporate soil type, CPT tip and sleeve resistance, and uncertainties in seismic demand and resistance. The resulting Bayesian correlations were presented in both probabilistic and deterministic formats and compared favorably to previous correlations.

Abstract

This paper presents a complete methodology for both probabilistic and deterministic assessment of seismic soil liquefaction triggering potential based on the cone penetration test (CPT). A comprehensive worldwide set of CPT-based liquefaction field case histories were compiled and back analyzed, and the data then used to develop probabilistic triggering correlations. Issues investigated in this study include improved normalization of CPT resistance measurements for the influence of effective overburden stress, and adjustment to CPT tip resistance for the potential influence of "thin" liquefiable layers. The effects of soil type and soil character (i.e., "fines" adjustment) for the new correlations are based on a combination of CPT tip and sleeve resistance. To quantify probability for performance-based engineering applications, Bayesian "regression" methods were used, and the uncertainties of all variables comprising both the seismic demand and the liquefaction resistance were estimated and included in the analysis. The resulting correlations were developed using a Bayesian framework and are presented in both probabilistic and deterministic formats. The results are compared to previous probabilistic and deterministic correlations.