Sydney Metro is the biggest urban rail project in Australian history. Sydney Metro West (SMW) is a 24km (15 mile) underground expansion of Sydney Metro that will link the Parramatta and Sydney central business districts (CBDs) and the communities in between.
The completion of the SMW line is part of the Future Transport Strategy's vision of "30-minute cities," with a goal of improving public transport networks and services to ensure 30-minute access to key destinations 24/7.
SMW is being delivered in three stages: Central Tunnelling Package (CTP); Western Tunnelling Package (WTP); and Delve Underground's scope, Eastern Tunnelling Package (ETP). The first two stages, CTP and WTP, are currently under construction. ETP, which is 3.5km (2.2 miles) of tunnel will service growing populations of the western suburbs of Sydney, Australia, from greater Parramatta to Sydney CBD. It will provide the missing link between the inner west suburb of The Bays to Sydney CBD.
Detail Design Scope
In December 2022, Delve Underground began delivering the detail design and as of May 2024 it had successfully completed the design. Delve Underground's detail design scope on ETP included:
· The approximately 2.3km long twin bored tunnels located between the new Hunter Street Station in the centre of the Sydney CBD, and the new The Bays Station located between Glebe Island and the White Bay Power Station. The tunnels are being excavated using two TBMs and are segmentally lined, with an inner diameter of approximately 6.2m (20.3ft).
· Excavation and primary support of the Pyrmont Station Cavern and Crossover Cavern and associated pedestrian access and service adits by roadheaders. The excavated spans of the caverns are approximately 24m (78.7ft) with limited ground cover. The expected ground conditions for the caverns vary from competent Hawkesbury Sandstone to complex geological structure associated with the Luna Park Fault Zone.
· Waterproofing and permanent lining of the Pyrmont Station Cavern and Crossover Cavern, including plenum slabs and deflection walls in the Crossover Cavern and associated pedestrian access and service adits. The waterproofing and permanent linings are designed for a service life of 120 years. The various permanent linings range from bar-reinforced concrete to steel fibre-reinforced concrete as well as unreinforced concrete.
· Excavation, primary support, waterproofing, and permanent linings for the cross passages between the bored tunnels, which are spaced approximately every 240m (787ft) along the alignment. Delve Underground's scope also includes the temporary opening support for the cross passages and first-stage concrete invert of the bored tunnels.
· Temporary works for the launch and retrieval of TBMs and site establishment.
· Proof engineering of excavation and primary support designs by other designers on the project.
Delivering a project of this scale requires companywide collaboration. Thus far, a total of 100 employees across three countries and four time zones have worked on this project to deliver the detail design.
CPS Scope
Delve Underground began construction phase services (CPS) in February 2024. Its CPS scope includes tunnel face and shaft geotechnical mapping at the Pyrmont Station sites and at cross passages between TBM tunnels. This work provides assurance that the observations made by the CPS team compare the encountered ground conditions with the anticipated ground conditions assumed during the design phase. Delve Underground will also provide inspections of the ground conditions encountered by the TBMs, if needed.
