Deep Basement Construction an Auckland Case Study

Parklands Apartments is a sixteen storey hotel development on the fringe of Auckland's CBD with thirteen storeys above ground and three basement car park floors. Within the constrained site there was a steep cross fall such that the excavation on the road frontage was the full three storeys deep whilst at the back of the site the excavation was limited to a single storey. To facilitate the construction of the basement and satisfy the concerns of adjacent property owners three different construction methods were adopted bottom-up, top-down and open excavation. Soil nailing was utilised on two elevations to provide temporary support as the excavation progressed to the basement formation. The paper describes the preliminary investigations and basement construction techniques adopted. Load test results on prototype and production soil nails are presented. The influence of installation methods and the performance of the nails in terms of load displacement and wall deformations are discussed.