27\/10\/2025<\/p>\n<\/div>
<\/div>T2D in Adelaide: Soletanche Bachy at the Heart of South Australia\u2019s Largest Infrastructure Project<\/h1><\/div>
T2D in Adelaide: Soletanche Bachy at the Heart of South Australia\u2019s Largest Infrastructure Project<\/h1><\/div><\/div>\n <\/p>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nThe River Torrens to Darlington (T2D) project is the largest infrastructure project ever undertaken in South Australia. With 10.5 km of urban highway, including 7.5 km of twin tunnels, it will complete the North-South corridor, providing Adelaide with 78 km of continuous highway without traffic lights. The GFWA-SBI joint venture is constructing diaphragm walls, barrettes, a ventilation shaft, and soil improvement. This strategic project will transform mobility in the region and bring lasting improvements to the daily lives of its residents.<\/strong><\/span><\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div><\/div>A 10.5 km urban highway, including 7.5 km of tunnels<\/span><\/p><\/h2><\/div>The T2D project is the final link in the North-South corridor, which will eventually total 78 km of continuous highway, without traffic lights, through the Adelaide metropolitan area.<\/span><\/span>
\nIts flagship feature: two twin tunnels, each 7.5 km long, 15m in diameter and with three lanes, drilled using three tunnel boring machines<\/strong> (rather than two as initially planned) to speed up the schedule. This decision required the exceptional mobilization of up to six diaphragm wall rigs<\/strong> working in parallel.<\/span><\/span><\/p>\n<\/div>The largest infrastructure project in the history of the State of South Australia<\/span><\/p><\/h2><\/div>With a budget of\u00a0AUD 15.4 billion<\/strong>, jointly funded by the Australian and South Australian governments, T2D is the largest project ever undertaken in the region.\u00a0<\/span>Its objectives are clear:<\/span><\/p>\n\n- Improve traffic flow and reduce chronic congestion<\/strong><\/span><\/span><\/li>\n
- Improve road safety,<\/strong><\/span><\/li>\n
- Boost the local economy<\/strong>\u00a0through better connectivity between the north and south of the city.<\/span><\/span><\/li>\n<\/ul>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div>\n
![](\"https:\/\/www.soletanche-bachy.com\/wp-content\/uploads\/sites\/18\/2026\/08\/DJI_20250617122346_0058_D-scaled.jpg\" "\\"DJI_20250617122346_0058_D\\"")
<\/span><\/div><\/div><\/div><\/div>![](\"https:\/\/www.soletanche-bachy.com\/wp-content\/uploads\/sites\/18\/2026\/08\/20250904_1050110-scaled.jpg\" "\\"20250904_105011(0)\\"")
<\/span><\/div><\/div><\/div><\/div>Soletanche Bachy’s expertise at the forefront<\/span><\/p><\/h2><\/div>The GFWA<\/a> \u2013 Soletanche Bachy International joint venture won this major contract, under an Incentivised Target Cost (ITC) contract, thanks to its ability to mobilize a record number of diaphragm wall<\/a> rigs for Australia, which will enable the Alliance in charge of the main contract to deploy three tunnel boring machines instead of two, thereby shortening the project timeline.<\/span><\/span>
\nThis approach requires an accelerated pace for the preparatory work, particularly on the diaphragm walls for the first two portals, which must be completed by the end of 2025. This will give the green light for the assembly of the tunnel boring machines in early 2026.<\/span><\/span><\/p>\nAfter several months of negotiations and method and program optimization, the contract was signed at the end of January 2025, and the teams began work on site in May.<\/span><\/span><\/p>\nOur work is spread over five sites covering more than 10 km and includes:<\/span><\/span><\/p>\n
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The River Torrens to Darlington (T2D) project is the largest infrastructure project ever undertaken in South Australia. With 10.5 km of urban highway, including 7.5 km of twin tunnels, it will complete the North-South corridor, providing Adelaide with 78 km of continuous highway without traffic lights. The GFWA-SBI joint venture is constructing diaphragm walls, barrettes, a ventilation shaft, and soil improvement. This strategic project will transform mobility in the region and bring lasting improvements to the daily lives of its residents.<\/strong><\/span><\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div> A 10.5 km urban highway, including 7.5 km of tunnels<\/span><\/p><\/h2><\/div> The T2D project is the final link in the North-South corridor, which will eventually total 78 km of continuous highway, without traffic lights, through the Adelaide metropolitan area.<\/span><\/span> The largest infrastructure project in the history of the State of South Australia<\/span><\/p><\/h2><\/div> With a budget of\u00a0AUD 15.4 billion<\/strong>, jointly funded by the Australian and South Australian governments, T2D is the largest project ever undertaken in the region.\u00a0<\/span>Its objectives are clear:<\/span><\/p>\n Soletanche Bachy’s expertise at the forefront<\/span><\/p><\/h2><\/div> The GFWA<\/a> \u2013 Soletanche Bachy International joint venture won this major contract, under an Incentivised Target Cost (ITC) contract, thanks to its ability to mobilize a record number of diaphragm wall<\/a> rigs for Australia, which will enable the Alliance in charge of the main contract to deploy three tunnel boring machines instead of two, thereby shortening the project timeline.<\/span><\/span> After several months of negotiations and method and program optimization, the contract was signed at the end of January 2025, and the teams began work on site in May.<\/span><\/span><\/p>\n Our work is spread over five sites covering more than 10 km and includes:<\/span><\/span><\/p>\n<\/div>
\nIts flagship feature: two twin tunnels, each 7.5 km long, 15m in diameter and with three lanes, drilled using three tunnel boring machines<\/strong> (rather than two as initially planned) to speed up the schedule. This decision required the exceptional mobilization of up to six diaphragm wall rigs<\/strong> working in parallel.<\/span><\/span><\/p>\n<\/div>\n
<\/div><\/div><\/div><\/div><\/div><\/div>\n<\/span><\/div><\/div><\/div><\/div><\/span><\/div><\/div><\/div><\/div>
\nThis approach requires an accelerated pace for the preparatory work, particularly on the diaphragm walls for the first two portals, which must be completed by the end of 2025. This will give the green light for the assembly of the tunnel boring machines in early 2026.<\/span><\/span><\/p>\n
![](\"https:\/\/www.soletanche-bachy.com\/wp-content\/uploads\/sites\/18\/2026\/08\/20250826_114342-scaled.jpg\" "\\"20250826_114342\\"")
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