A critical comparison between stress and energy based methods for the evaluation of liquefaction potential

Abstract

Selected liquefaction case histories in New Zealand during recent earthquakes were analysed using the conventional SPT and CPT stress based methods, and the energy based method recently proposed by Kokusho (2013). Several sites in the wider Christchurch region were examined considering strong motions from the 2010-2011 Canterbury Earthquake Sequence. The liquefaction potential was also examined at three sites in the Wellington and Marlborough regions for the 2013 Mw6.6 Lake Grassmere and 2016 Mw7.8 Kaikoura earthquakes. The methods were compared in terms of the critical liquefaction depth and layer thickness, data scatter and number of false-negative predictions. The Kokusho energy based method performed satisfactorily in assessing the liquefaction potential at the case history sites, giving comparable results to the stress based methods. Furthermore, the Kokusho method succeeded in identifying liquefaction potential at several sites in Christchurch where false-negative predictions were shown in the CPT stress based method.