The current practice in New Zealand for seismic design of shallow foundations is to ensure the LRFD inequality is satisfied, meaning not all of the available bearing strength is mobilised. However, the occurrence of bearing failure may be acceptable, provided the resulting permanent displacements are also…
Abstract Pumice materials, which are problematic from an engineering viewpoint, are widespread in many parts of the North Island. Following the 2010-2011 Christchurch earthquakes, a clear understanding of their properties under earthquake loading is necessary. For example, the 1987 Edgecumbe earthquake showed evidence of localised…
Abstract Expansive soil has been well recognised as a problematic soil due to its swelling and shrinkage behaviour during wetting and drying cycles. The swelling pressure developed upon wetting is often investigated by placing an initially unsaturated soil specimen into an oedometric cell modified to…
Abstract At 12.03 am local time on 14th November 2016 (UTC: 11.03 am 13th November 2016) a shallow, magnitude 7.8 earthquake struck near Waiau in North Canterbury, NZ. Strong ground shaking affected the North Canterbury and Marlborough regions of the South Island, causing widespread damage…
Abstract The NZ Transport Agency’s Waterview Connection project involves the construction of 5 km of motorway to complete Auckland’s Western Ring Route. Half of this new link is twin 14.5 m diameter tunnels constructed by Tunnel Boring Machine with 16 sequentially excavated cross-passages. Over most…
Abstract A routine part of any geotechnical investigation is the classification of the recovered soils. In New Zealand this should be undertaken in the field in accordance with the New Zealand Geotechnical Society’s guidelines. There is a general expectation that laboratory-based methods should both verify…
Abstract The near surface geology of the Auckland area generally comprises alluvial soils, volcanic tuff/ash and/or residual soils. These soils may be expected to display different engineering characteristics given their different geological origins. The soils are mostly cohesive and the undrained shear strength, su, is…
Abstract The underlying failure mechanism at the Omoto Slip is translational soil creep of the 5-30 m thick colluvium cover over the Kaiata Mudstone bedrock erosional surface that extends across the entire Omoto slope area. This is driven by major evacuative failures at the toe…
Abstract Three concrete arch dams (Mahinerangi Dam, Waipori Nos. 2 and 4) and one gravity weir (Waipori No.3) of varying ages provide the impoundments for the Waipori Hydro-electric Scheme. Findings of a comprehensive dam safety review carried out in 2012 indicated some knowledge shortcomings when…
Abstract Unsecured draperies are routinely used as a rockfall mitigation system. These systems do not completely eliminate the rockfall hazard and are typically classified as passive structures aiming primarily at controlling rockfall motions by constraining them towards the slope. Rockfall hazard is seldom completely eliminated,…