UEA Trenchless was awarded an 80m bore beneath the racetrack at Royal Randwick Racecourse for Laing O’Rourke. The bore forms part of the Australian Turf Club (ATC) temporary car park works currently being undertaken by Laing O’Rourke. The bore is required to install 80m of DN350 S Series Class 4 RC Jacking Pipe (RCP) on a 0.5% grade.
The Geotechnical Information provided for the bore indicates the ground to be Botany Sands: ‘fine to medium grained, pale grey to pale brown, with trace silt’.
For this bore UEA proposed to use their Akkerman Laser Guided Boring Machine (GBM) to complete an on grade pilot bore. Following the completion of the pilot bore, UEA will use a conventional auger boring machine to install a steel enveloper pipe. The lead case will have a splitter head installed with the lead auger positioned 500mm back inside the lead case to avoid syphoning.
Once the steel enveloper is installed, UEA will jack in the RCP on centralisers within the steel enveloper and grout the annular gap, both between the enveloper pipe and the ground and also between the RCP and steel enveloper pipe.
The critical element of this bore is to avoid ground syphoning and heave, as this can be detrimental to the race track. UEA’s GBM capabilities are specifically designed for displaceable/sandy ground.
UEA have programmed 3 weeks to undertake these works, which includes all elements of works associated with completing the bore and meeting with all client and standard HSEQ requirements. The site will be left fully restored upon installation of the carrier pipe.