Work is now underway on the River Torrens to Darlington Project in South Australia – the largest infrastructure project in the state
Main construction works are officially underway on the largest and most complex infrastructure project in South Australian history.
Heavy machinery is on site and construction activity has ramped up at the Southern Precinct in Clovelly Park, marking the start of major works on the River Torrens to Darlington (T2D) Project that will create a non-stop South Road.
The non-stop South Road project will allow motorists to bypass 21 sets of traffic lights between the River Torrens and Darlington, saving up to 40 minutes of travel time in peak hour traffic.
It’s estimated up to 550 workers will be employed at the Southern Precinct during peak construction, with the entire T2D Project to support approximately 5,500 jobs per year during main construction – with 90 per cent of labour hours to be undertaken by South Australians.
The $15.4 billion T2D project is jointly funded by the federal and SA state governments, with each contributing $7.7 billion.
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 the Tunnel Boring Machines (TBMs) will launch to construct the southern tunnels.
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Two TBMs will launch from the Southern Precinct to construct the twin 4.5km Southern Tunnels, while the twin 2.2km Northern Tunnels will utilise a third TBM. TBM works for the Southern Tunnels are planned to begin in the second half of 2026.
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 35m 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.
A nearly 100m-long bentonite plant has also been constructed. This will produce and recycle bentonite slurry – a wet clay that is pumped into the trenches being excavated for the diaphragm walls to ensure ground stability. A water treatment plant, which will help the project treat and reuse water during the tunnelling process, has also been constructed.
The Alliance awarded its first package of works for a $6 million link road between Norrie Avenue and English Avenue, Clovelly Park, which is being delivered by local contractor, McMahon Services. The new link road opened to traffic on Sunday, 11 May 2025.
These works will enable the planned temporary closure of Celtic Avenue, which is necessary for the construction of the Southern Tunnel portal and the TBM launch area. The new signalised intersection will maintain connectivity to and from South Road for the local community during this closure.