The 14 November 2016 Mw7.8 Kaikoura Earthquake caused widespread liquefaction in CentrePort, Wellington, resulting in substantial lateral ground movement, global and differential settlements, and large volumes of soil ejecta. Following the earthquake, a subsurface exploration program was executed consisting of CPTs and surface wave testing to characterize the thick end-dumped gravelly fills and hydraulically-placed dredged reclamations.

The complex subsurface soil composition for the gravelly fills contain mixtures of gravels, sands, and some non-plastic fines. The hydraulic fills were constructed recently by slurry deposition of seabed materials with little compaction. This study uses the extensive subsurface data to produce detailed subsurface soil profiles for the Port of Wellington, and then scrutinizes the applicability of simplified procedures for liquefaction assessment of the reclamations.

Ranges for the penetration resistance and soil behavior type index values are provided for the characteristic soil layers at the port. The spatial distribution of the end-dumped gravelly fills and sandy hydraulic fills at the port are presented. Some of the areas of the port also contain soils with significant fines (both non-plastic and plastic). The liquefaction susceptibility and potential of the different soil deposits within the port are assessed and compared to the observed field performance. State of the practice simplified procedures are used to evaluate liquefaction triggering and ground damage indices. Emphasis is placed on the investigation of the robustness of conventional procedures in their ability to capture the liquefaction resistance and cyclic response of the reclaimed soil.