Liquefaction Response of Gravel-Sand-Silt Reclamations from 1D Effective Stress Analysis

Abstract

The 2016 M_w7.8 Kaikōura earthquake caused widespread liquefaction in the port of Wellington, New Zealand (CentrePort). Several challenges and limitations in the engineering evaluation of soil liquefaction for CentrePort reclamations have been identified when utilizing semi-empirical procedures as they comprise mixtures of gravel, sand, and silt. This paper presents results from 1D effective stress analysis (ESA) performed on representative soil profiles of the gravelly reclamations to gain insights into the liquefaction response in addition to observations from the Kaikōura earthquake. Key steps in the analyses are first presented, including calibration of appropriate constitutive relationships. Results from analyses are presented to illustrate the effects of dynamic interactions within liquefying reclamations including how the response evolves from localized liquefaction at some depths to thick liquefied zones in the fill with increasing intensity of the earthquake excitation. Comparisons are also made between conventional simplified methods and ESA through damage index calculations.