Sydney Metro West – WTP Project Wide .
Concrete surface repairs, structural crack injection and polyurethane injection to treat groundwater ingress in in segmentally and cast in-situ lined tunnels and station boxes.
The Western Tunnelling Package (WTP) forms a significant part of the Sydney Metro West project and is being delivered by the Gamuda Laing O’Rourke Consortium (GLC). This package comprises the construction of twin 9-kilometre tunnels stretching from Sydney Olympic Park to Westmead. It also includes major excavation works for a service and crossover facility at Rouse Hill, tunnel portal and dive structures at Clyde, and large-scale station box excavations at Parramatta and Westmead.
GLC’s scope involves bulk excavation and primary support works across various underground structures, including station boxes supported by diaphragm walls, precast segmentally lined running tunnels, and cross passages formed using cast in-situ concrete.
Numerous structural interfaces across these works are prone to water ingress. These include construction joints between diaphragm wall panels in station boxes, segment gaskets in the running tunnels, and the waterproofing transitions between precast tunnels and in-situ cross passages. Additionally, precast tunnel segments are often damaged during TBM installation, particularly at edges and around segment erector cones formed for vacuum lifting which require repair.
Direct Inject has been appointed to deliver specialised remediation and leak-sealing services within the precast tunnels and associated underground structures. This includes repairing spalled or damaged segment edges and lifting pockets, injecting cracks within the internal segment face, and applying polyurethane resins to seal leaks originating from gasket joints, D-wall panels and voids in the annular grout.
We are also addressing persistent seepage at construction joints within cross passages and at their interfaces with the running tunnels. Our work involves the strategic use of polyurethane and acrylic gel injection to restore watertightness and enhance the durability of these high-risk structural zones.
Our operations are being carried out concurrently with and following TBM excavation works, often in restricted environments with active logistics and material handling underway. Direct Inject continues to provide critical support to GLC, helping to ensure sections of the project progress toward completion through the delivery of precise, reliable, and efficient remediation services.
