Melbourne Crown Casino – Geotechnical Issues

Max Ervin

The Melbourne Crown Casino, billed as one of the largest in the world, has been built on about a 6 hectare site on the south bank of the Yarra River in Melbourne. The $1.6 billion project includes 11 hectares of underground car parking, on two levels, theatres, gaming halls, restaurants and a 40 storey hotel. The Casino opened on May 8, 1997. Golder Associates undertook geotechnical investigations for the project, on behalf of the Casino developer, Crown Limited. Ground conditions at the site comprise up to 20 metres of soft to firm clay (Coode Island Silt) overlying stiff clay, dense sands and gravels with the Silurian age basement rock of variably weathered siltstone encountered at about 30 metres depth. Basalt rock is present at shallow depth over the northern part of the site. The two level basement was undrained and the associated buoyancy forces accommodated as necessary by tension piles socketed into the siltstone or the basalt. A groundwater protection system was developed comprising a bentonite-cement cut-off wall to about 10 metres depth, with additional protection from the installation of an hydraulic wall comprised of wick drains installed at close centres to about 20 metres depth. Max Ervin was extensively involved with the investigation, design and construction phases of this very challenging project. He will describe the geotechnical investigations undertaken, the design solutions adopted, and the numerous construction issues which arose. In particular, the groundwater protection system developed to avoid regional effects, the construction of some 950 bored piles with bentonite slurry support, and stability issues associated with the temporary cut batters used for the basement excavation will be discussed.

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