Scrutiny of CPT-based liquefaction assessment procedures using case histories from the 2016 Kaikoura earthquake, New Zealand

This paper explores the most recent set of liquefaction observations in New Zealand which resulted from the 2016 M(W)7.8 Kaikoura earthquake, in which widespread manifestations of liquefaction occurred in the north of the South Island of New Zealand. Groundwater and ground motion models were developed for the affected region, which are implemented in the simplified CPT-based liquefaction assessment procedure using geotechnical data located in areas with and without surface manifestation. Combining the outcomes from these assessments with observational datasets provides a greater understanding of the predictive efficacy of these simplified frameworks and their applicability in engineering design and other applications. Areas where predictions are inconsistent with the observations are readily identified, highlighting some of the root causes for false-predictions. The case studies support the idea that hydraulic continuity between layers is fundamental to the system response of the soil profile, with inhibition of vertical dissipation of pore water pressures greatly reducing the likelihood of surface manifestations.