The TBMs being used to construct the T2D tunnels will be about 100 m in length and 15 m in diameter. The new smaller 4.1 m-diameter ones will be used to save time on the project by constructing the cross-passages between each of the tunnels. Photo: T2D.
The South Australian Government has been in Germany to lock in the purchase of up to twice the number of tunnel boring machines (TBM) than previously expected for its River Torrens to Darlington Project (T2D).
T2D is the final 10.5-km section of Adelaide’s North-South Corridor, completing 78 km of non-stop, traffic light-free motorway between Gawler and Old Noarlunga.
It will be the biggest ever infrastructure project for the state and is being jointly funded with the Federal Government. The state has also selected an alliance to deliver T2D, comprising John Holland Bouygues Construction, Arcadis Australia, Jacobs and Ventia.
Accompanied by the consortium of contractors in Schwanau, a municipality just over the border from Strasbourg, the State Government formally sealed a contract to purchase three initial TBMs from world-leading manufacturer Herrenknecht.
Following a signing ceremony and tour of the manufacturer’s headquarters, Infrastructure and Transport Minister Tom Koutsantonis also confirmed plans to purchase two additional, smaller TBMs – with another likely to follow.
These will be used to carry out excavation work between the main tunnels, where equipment will be housed to support day-to-day operations. They will also form part of the tunnel’s safety systems as they provide a means to exit any emergency situation that may arise during construction.
Herrenknecht has provided TBMs across the world, including Australia where it’s been involved with projects such as the Sydney Metro, and the North East Link and West Gate Tunnel projects in Melbourne.
The first of three TBMs is expected to arrive in late 2025. Its components will be manufactured in Germany and China, before being assembled and factory assurance tested in China.
The State Government said once the TBMs were in Adelaide it would take time to assemble and commission the TBMs before they could start tunnelling works.
The T2D Alliance is confident they can deliver the project on budget, with companies involved having already delivered projects like the WestConnex, Southwest Tunnels, Station Excavation and Sydney Airport Rail Link.
All the TBMs ordered are expected to cost around $180 million, with main construction works proposed to start in 2025.
The procurement of the three initial TBMs for the major tunnelling works was so they could construct both the northern and southern tunnels at the same time.
Minister Koutsantonis claims there’s a reasonable expectation that the project can be completed by the stated 2031 deadline, “if not even earlier”.
Altogether the project is expected to support about 5500 jobs per year during main construction – with 90 per cent of labour hours to be undertaken by South Australians.
The SA Infrastructure Minister said the ink was still wet on the T2D main construction contract, but the project was already moving forward swiftly.
“These are seriously big pieces of kit, and today’s (29 September) purchase represents one of the biggest purchases of building equipment in South Australia’s history,” he said.
“We are getting closer to the start of major works and it won’t be long until the dream of saving 30 to 40 minutes of travel time between West Hindmarsh and Darlington becomes a reality.”
