Managing contractor Mossop Construction + Interiors and civil subcontractors Wagstaff Piling and McMillan Contracting are currently undertaking the in-ground works which will form the eastern clinical developments underground car park and will allow the subsequent construction of the clinical areas above ground.
The in-ground construction must be designed, both to retain the surrounding soil and also to create a water proof barrier against the artesian water which flows beneath the Adelaide plains. To achieve this a diaphragm wall construction has been implemented by the design team. A series of narrow and very deep trenches are excavated around the perimeter of the building, which are progressively filled with an engineering fluid to prevent the trenches collapsing or filling with water. Once the trench has reached the required depth steel reinforcing is dropped in and concrete is pumped into the base of the trench progressively displacing the engineering fluid.
By installing the diaphragm walls to a depth of 16 metres below ground level, the diaphragm wall anchors into the water impervious Hindmarsh Clay soil stratum creating a water proof barrier against artesian water which flows in the shallower Alluvium and keswick Clay soil stratums.
Once the diaphragm wall is complete, excavation of the soil will commence with over 16,000 cubic metres of fill (soil) being removed in the works, enough soil to fill over six Olympic swimming pools. This fill will be recycled for use on other construction projects within South Australia.