Application of a multi-technique ground engineering solution to overcome geotechnical and physical challenges in Docklands

A high-grade mixed-use development has been proposed in the heart of Melbourne, Australia situated on the banks of the Yarra River. The proximity of the project to an existing heritage-listed seawall dock structure required the detailed design and analysis of proposed foundation and retention system to ensure all adjacent structures were protected and the project specifications and performance criteria are met. The proposed project consisted of a single level basement in very soft clays with a high groundwater table and deep foundation piles socketed into a bedrock at depths exceeding 35m. This paper describes the methodical process of assessing and implementing a sheet pile solution to protect and maintain the integrity of the existing seawall for the enabling and pile installation works. The building is supported by deep foundation Continuous Flight Auger (CFA) piles with column loads exceeding 35MN with dynamic pile testing being carried out for performance verification. The paper also shares the application of the wet mass soil mixing (MSM) ground improvement technique combined with the conventional soldier piled wall for an internal deep excavation to construct the core and lift overrun structures for the building. The purpose of the MSM was to act as a bottom strut to a soldier piled wall and a barrier to control lateral and vertical flow of soft soils and groundwater.