T2D tunnelling history
The Albanese and Malinauskas Labor Governments’ $15.4 billion River Torrens to Darlington (T2D) Project is set to achieve a major milestone in the coming days, with all three of its large-scale Tunnel Boring Machines (TBMs) to be operational this week. TBMs Catherine and Elizabeth are in the final stages of preparations and are expected to start excavating in coming days, joining TBM Mary, which has already carved around 100 metres beneath South Road.
This marks the first time in Australian history that three large-scale TBMs are tunnelling simultaneously on the same underground road project. The milestone comes less than two years after the contracts were signed to purchase the mega machines, which will excavate the tunnels that will complete the final piece of Adelaide’s North-South Corridor. As the mega machines make their way beneath South Road the millions of tonnes of excavated material will need to make its own journey to the surface.
Together, the trio will excavate around five million tonnes of rock and soil, known as spoil, as they construct the northern and southern tunnels. Spoil will travel from the TBMs by conveyor to the spoil shed before being loaded into covered trucks, then transported to the re-use site at Gillman. Around 7.5 million tonnes of spoil is expected to be generated across the whole T2D project, including approximately 5 million tonnes from tunnelling and a further 2.5 million tonnes from civil works.
Each stretching around 100 metres in length and weighing 3,500 tonnes, the TBMs are the largest pieces of construction equipment ever used in South Australia. TBM Mary was first to begin her journey beneath South Road from the project’s Southern Precinct at Clovelly Park, with Catherine now preparing to join her on the 4.5-kilometre journey towards Glandore to construct the twin southern tunnels.
Further north, TBM Elizabeth is preparing to start her journey from the project’s Central North Precinct at Hilton, excavating the first of the 2.2-kilometre northern tunnels toward the Brickworks Marketplace at Torrensville. Once there, Elizabeth will be turned around and reassembled for the southbound return journey to Hilton. The use of three large-scale TBMs allows both the northern and southern tunnels to be constructed concurrently, helping deliver a non-stop South Road by 2031.
Tunnelling across the project will take up to 24 months, with significant work to continue after the TBMs finish their journeys. This includes building the road within the tunnels, installing safety, mechanical and electrical systems, testing and commissioning, and completing compliance checks. The open motorway section, including bridges and footpaths, will also need to be completed and connected to the tunnels.
The T2D Project is the final 10.5-kilometre section of the North-South Corridor, and will complete 78 kilometres of non-stop, traffic light-free motorway between Gawler and Old Noarlunga. Quotes attributable to Federal Minister for Infrastructure, Transport, Regional Development and Local Government Catherine King: “With TBM Catherine and Elizabeth getting underway, this is the first time in Australian history that three large-scale TBMs are tunnelling simultaneously on the same underground road project.
“This is yet another exciting milestone in this nationally significant infrastructure project, which will connect Adelaide from north to south. “The completed T2D project will transform access to Adelaide Airport, Port Adelaide, the national highway network and more.” Quotes attributable to South Australian Minister for Infrastructure and Transport Joe Szakacs: “We’re just days away from having all three of our massive TBMs from tunnelling.
“Mary has already carved around 100 metres, with Catherine and Elizabeth now in the final stages of preparations before starting their own journeys. “One TBM alone weighs about the same weight as eight or nine jumbo jets. At the completion of tunnelling for this project, 30,000 jumbo jet equivalents in soil weight will be moved.
“Together, the three TBMs will excavate around five million tonnes of rock and soil known as spoil as they construct the Northern and Southern Tunnels, so there’s an enormous operation happening both below and above ground.” Quotes attributable to Federal Member for Boothby Louise Miller-Frost: “The hard work continues on this massive project, with these incredible machines now carving a new north-south road link beneath Adelaide.
“This project will mean faster journeys across our city and take pressure off surrounding roads. There’s so much for our community to look forward to as we reach this exciting new stage.”