Perth, Western Australia
The old Belmont Golf Course, Burswood
The State Government of Western Australia is planning a new 60,000 to 70,000 seat major sports stadium within a proposed sports precinct on Burswood Peninsula, WA. To facilitate timely and cost effective construction of the project, a program of Pre-Construction Site (PCS) Works was completed across several designated areas within the precinct.
The PCS works contract, with a value of approximately $30M, was awarded to the Ertech Keller Joint Venture (EKJV). CMW Geosciences was engaged by EKJV to carry out the geotechnical design for the PCS works and to install and monitor the instrumentation to demonstrate compliance with a number of performance criteria.
The sports precinct is situated over the former Belmont Golf Course, which provided challenging ground conditions comprising 4m to 9m of Uncontrolled Fill associated with a former industrial waste dump overlying 2m to 24m of soft, normally to near normally consolidated, Swan River Alluvium (SRA). The PCS works focussed on initial earthworks, including draining and filling lakes within the former golf course site, dynamically compacting the Uncontrolled Fill and constructing wick drained earthfill embankments to consolidate the SRA.
Dynamic Compaction involved dropping impact hammers of up to 24t in weight from heights of up to 20m to compact the Uncontrolled Fill. Pre and post CPT and dynamic probe testing, together with other monitoring methods demonstrated that an improvement in the fill density was achieved to meet the project objectives.
The surcharge embankments were instrumented with surface settlement markers, vibrating wire piezometers, inclinometers and extensometers to measure the performance of ground settlement with respect to design assumptions and to verify predicted post construction ground performance. All instrument installations were logged by CMW and the soil fabric assessed with respect to published literature, which describes the SRA plasticity as being high to extremely high, variable with depth and anisotropic.
Detailed hand calculations, including back calculation of available embankment settlement data, review of reported geotechnical design parameters together with numerical PLAXIS analyses were completed to predict ground settlements. Surcharge embankments have now been constructed to their design height and monitoring is continuing. Initial results show that embankment settlements are generally within the range of design predictions.