The practice of saturating centrifuge models with a highly viscous pore fluid is widely used. As the fluid saturates the model, care must be taken to ensure that the hydraulic gradients are not too high to cause excessive disturbance to the model. A new computer-controlled saturation system (CAM-Sat) has been developed and implemented at the University of Cambridge to aid the saturation of soil models with a high viscosity pore fluid. Models are saturated under vacuum and pore fluid enters through ports in the model’s base. The system controls the ingress of pore fluid into the model by monitoring the fluid mass flux and then altering the pressure drop between a reservoir of pore fluid and the model. The system was found to be stable across a wide range of fluid viscosities and sand types. A further test showed that the system was able to respond to changes in mass flux demanded by the researcher.

The shaft friction capacity of a piled foundation is commonly linked to the effective stresses acting on the pile, and hence it is assumed that if the surrounding soil liquefies following an earthquake event, the shaft friction capacity of a pile drops to zero. In this paper an investigation into the axial load transfer during a liquefaction event based on dynamic centrifuge test results is presented. A free-standing pile group with the pile cap clear of the ground surface is considered, to clarify the mechanism of load transfer. The pile group was instrumented to measure axial loading at several locations along the pile length, and was embedded in a saturated soil profile where a dense permeable base layer was overlain by a layer of loose, liquefiable sand. The results show that shaft friction continues to be maintained during an earthquake in both loose and dense soil. In the case of loose soils, the apparent shaft friction capacity is proposed with reference to the shear taking place at the pile/soil interface, which causes a local reduction in the pore pressures.

The magnitude Mw7.8 ‘Kaikōura’ earthquake occurred shortly after midnight on 14 November 2016. This paper presents an overview of the geotechnical impacts on the South Island of New Zealand recorded during the post-event reconnaissance. Despite the large moment magnitude of this earthquake, relatively little liquefaction was observed across the South Island, with the only severe manifestation occurring in the young, loose alluvial deposits in the floodplains of the Wairau and Opaoa Rivers near Blenheim. The spatial extent and volume of liquefaction ejecta across South Island is significantly less than that observed in Christchurch during the 2010-2011 Canterbury Earthquake Sequence, and the impact of its occurrence to the built environment was largely negligible on account of the severe manifestations occurring away from the areas of major development. Large localised lateral displacements occurred in Kaikōura around Lyell Creek. The soft fine-grained material in the upper portions of the soil profile and the free face at the creek channel were responsible for the accumulation of displacement during the ground shaking. These movements had severely impacted the houses which were built close (within the zone of large displacement) to Lyell Creek. The wastewater treatment facility located just north of Kaikōura also suffered tears in the liners of the oxidation ponds and distortions in the aeration system due to ground movements. Ground failures on the Amuri and Emu Plains (within the Waiau Valley) were small considering the large peak accelerations (in excess of 1g) experienced in the area. Minor to moderate lateral spreading and ejecta was observed at some bridge crossings in the area. However, most of the structural damage sustained by the bridges was a result of the inertial loading, and the damage resulting from geotechnical issues were secondary.

The 2016 $Mw$ 7.8 Kaikōura earthquake triggered localized liquefaction and associated lateral spreading in the Wairau Plains on the South Island of New Zealand. Detailed postevent mapping from ground and helicopter‐based reconnaissance indicates that liquefaction predominantly manifested proximal to rivers and streams within the easternmost extent of the plains. In this study, pre‐ and postevent light detection and ranging (lidar) survey data and aerial photography are analyzed to further resolve maximum extents of liquefaction‐induced damage and to infer the presence and/or absence of liquefaction in areas that were not covered during reconnaissance surveys. Historical maps used in conjunction with local geomorphologic and topographic variability are shown to provide insights into the depositional settings of areas where liquefaction manifestations were observed. Cone penetration test (CPT) logs are additionally utilized to examine characteristics of the subsurface soil profiles in areas where liquefaction did and did not manifest. The various data sources indicate that the observed distributions of liquefaction manifestations within the lower Wairau Plains correlate with basic depositional processes of meandering rivers and correspond with the position of point‐bar and paleochannel deposits. This study highlights the potential applications and benefits of incorporating geomorphic and topographic variability into liquefaction hazard assessments.

The moment magnitude (M_w) 7.8 Kaikōura, New Zealand, earthquake triggered relatively few cases of liquefaction and related phenomena (e.g., lateral spreading) despite the large magnitude of the event. Cases of severe liquefaction manifestation were confined to localized areas proximal to waterways near the township of Blenheim, in the north-eastern corner of the South Island of New Zealand. The occurrence and non-occurrence of liquefaction within the wider Blenheim area is shown to closely correspond with fluvial geomorphology and associated depositional setting of the sediments. Herein, the distribution of liquefaction within the region is detailed in the context of the geomorphological influences and sedimentologic controls. This work highlights the influence of geomorphic variability on the occurrence of liquefaction, with the aim of improving the assessment of liquefaction hazards for future events worldwide.