Project Overview:
Sydney Water, alongside the Department of Planning and Environment, Councils and other utility providers are planning and building the Austral Leppington Wastewater Stage 3 project. The project will provide safe and reliable drinking water and wastewater to service growth in the Austral and Leppington precincts.
The project includes the construction and operation of:
• new wastewater pumping station along Gurner Avenue
• permanent access road within the pumping station
• 1.7 kilometres of a new wastewater pressure main
• 6.9 kilometres of trunk wastewater mains
• 1.7 kilometres of wastewater lead-ins
• 3.6 kilometres of trunk water mains along Kelly Street, Tenth Avenue and Edmondson Avenue
Project Description:
Quickway were engaged to perform early enabling works which included Hardstands, Laydown areas, Access Roads, and Temporary culverts for Sydney Water/WRDT.
Quickway were also contracted to undertake excavation works for deep shafts (launch and receive holes) to enable the Micro tunnelling contractors to complete the tunnelling works between the Sewer Maintenance Holes. Excavation works of the shafts were on average 7m (L), 5m (W) and approximately 8.5m deep.
Upon Completion of the micro-tunnelling works Quickway installed prefabricated GRP Manholes/connections along the main carrier. As well as the installation of precast components. In addition to the manholes, Quickway also installed vent shafts approximately 14m high.
Key Challenges:
Significant water ingress into deep shafts both during excavation and after completion of the shaft were a challenge faced during construction. This is due to the naturally high water-table and significant flood prone environment. This required more complex excavation works and ground support systems to be used.
Being the first to install GRP manholes with Sydney Water in this area, Quickway’s methodology and scope of works were followed closely and were successful in demonstrating the practicability of GRP manholes in comparison to In-situ manholes.
The size of the GRP manholes created a challenge which required a critical lift procedure to rotate the manhole from horizontal position to vertical position for installation.
Quickway completed maintenance shaft installation at twenty different locations along the Austral Carrier lines, most of which where in confined areas with limited space, some with a high volume of underground and overhead assets. In addition to this, Quickway completed this works in Austral-Leppington’s high growth area and needed to be aware of a variety of residents and developers within the Austral area.