Major works underway on largest ever SA infrastructure project

Construction activity is ramping up on the first major works for the $15.4 billion River Torrens to Darlington (T2D) Project in South Australia.

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. Drivers will be able to bypass 21 sets of traffic lights between the River Torrens and Darlington as they travel through two separate tunnels, connected by an open motorway.

Heavy machinery is on site and construction activity has ramped up at the Southern Precinct in Clovelly Park. The Southern Precinct – located between Tonsley Boulevard and Norrie Avenue on the western side of South Road – will become the purpose-built site from where Tunnel Boring Machines (TBMs) will launch to construct the southern tunnels.

These two TBMs will launch from the Southern Precinct to construct the twin 4.5-kilometre Southern Tunnels, while the twin 2.2-kilometre Northern Tunnels will utilise a third TBM. TBM works for the Southern Tunnels are planned to begin in the second half of 2026.

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The three TBMs were purchased in September 2024 from manufacturer Herrenknecht based in Schwanau, Germany. The TBM components are being manufactured in Germany and China, before being assembled and factory assurance tested in China, and then delivered to Adelaide by ship. The first of three TBMs is expected to arrive in late 2025.

Two additional, smaller TBMs will also be used to carry out excavation work for cross passages between the main tunnels.

The past few weeks have seen a significant increase in works on site, including the start of construction of the diaphragm walls for the TBM launch box – the first piece of permanent works on the project. The diaphragm walls will be up to 35 metre deep and form the outside of the TBM launch box – a large open trench where the TBMs will be assembled and then begin excavating the tunnels.

Nadia Clancy, State Member for Elder thanked locals for their patience during construction.

“The Southern Precinct is really taking shape, and I’m so grateful to residents around the site for their incredible patience as the Government delivers this incredibly significant project,” Clancy said.

“The completion of the new link road between Norrie Avenue and English Avenue in Clovelly Park will be a huge help for local motorists during other necessary closures.”