The Sydney Metro – Western Sydney Airport Station Boxes and Tunnelling Works (WSA-SBT) project was delivered by the CPB Contractors Ghella Joint Venture (CPBGJV). This major infrastructure package involved the construction of twin 9.8-kilometre tunnels, the bulk excavation of station boxes at St Marys, Orchard Hills, Airport Terminal Station, and Aerotropolis Station, as well as the excavation of service facility shafts at Bringelly and Claremont Meadows.
CPBGJV’s scope focused on excavation and initial structural support, including:
Several critical structural interfaces were identified as being susceptible to groundwater ingress. These included gasket joints between tunnel segments and waterproofing terminations where precast tunnels met in-situ structures such as cross passages. Minor damage to precast segments—particularly at segment edges and around erector cone pockets—was also observed during TBM operations.
Direct Inject was engaged as the primary contractor for specialised concrete remediation and water stopping injection works across the entire project. Our services encompassed repairs within the segmentally lined tunnels and injection works at key locations, including cast in-situ cross passages, stationboxes, shafts, dive structures and waterproofing terminations at tunnel portals.
We continue to support this valued client during the Defects Liability Period (DLP), addressing isolated items as required to ensure long-term structural performance and watertightness.
Our works were delivered alongside live construction activities, including active TBM operations, tunnel segment logistics, invert slab pours, and shaft and station box lining works. Direct Inject coordinated closely with the client to align our deployment across multiple work fronts with the evolving construction schedule, ensuring minimal disruption and seamless integration with other critical activities
