Work on the T2D Project will be broadly undertaken from south to north, beginning with the Southern Tunnels before moving onto the open motorway section, then the Northern Tunnels section.

Both the Southern and Northern Tunnels will be constructed using tunnel boring machines (TBMs). These machines will operate continuously, progressing about 8 to 10 metres a day.

Project timeline

Main construction works are planned to commence in 2025 with tunnel boring machine (TBM) tunnelling works for the Southern Tunnels planned to start in 2026. The Southern Tunnels will be open to traffic in 2030 after further tunnel fit-out and commissioning works.

The entire T2D Project will be open to traffic in 2031.

  • Project schedule
    Early 2022 to late 2031

  • Enabling Works
    Early-2022 to mid-2026
    Includes ground investigations, service relocations, demolition and a number of off-corridor upgrades.

  • Major works procurement
    Early 2023 to mid 2024
    Includes registration of interest, expression of interest, request for proposal and contract award.

  • Site establishment
    Mid 2024 to mid 2025
    Includes mobilisation of personnel, plant and the installation of site facilities.

  • Major construction
    Mid 2025 to late 2031

    • Tunnel boring commences mid 2026
    • Southern Tunnels open to traffic mid 2030
    • Northern Tunnels open to traffic late 2031

Laydown areas

Laydown areas will be established for the Northern and Southern Tunnels to provide starting points for our TBMs. Earthworks and site preparations will then be undertaken to allow for ongoing construction activities.

These laydown areas will be used to:

  • build the repurposed motorway
  • launch and support the ongoing operation of TBMs
  • enable the removal of underground material obtained through tunnel boring
  • store equipment and materials
  • provide facilities for construction workers.

After construction, much of the laydown areas will be transformed into the new motorway connecting to the tunnels. They will also be used for supporting infrastructure for long-term tunnel operations and part may be converted into community space.

Construction materials

The T2D Project will harness an enormous amount of local and imported construction materials to complete the project, including:

  • 57 km of pipes, equal to 114 laps of the Adelaide oval
  • 1.09 million cubic metres of concrete, equal to 436 Olympic sized swimming pools
  • 390 km of cables, conduit, and optic fibre, equal to 24.3 laps around Adelaide CBD
  • 275,000 tonnes of asphalt, equal to 6,875 Adelaide trams
  • 57 km of pipes, equal to 114 laps of the Adelaide oval
  • 1.09 million cubic metres of concrete, equal to 436 Olympic sized swimming pools
  • 390 km of cables, conduit, and optic fibre, equal to 24.3 laps around Adelaide CBD
  • 275,000 tonnes of asphalt, equal to 6,875 Adelaide trams

When completed, spoil material generated from excavation of the tunnel and actual tunnelling will amount to more than 8 million tonnes.

* Material values are estimates only and subject to change.

Construction Environmental Management Plan (CEMP)

The construction contractor will be required to ensure any construction impacts are proactively minimised, monitored and managed.

Prepared by the construction contractor, a CEMP will set out how impacts will be minimised and monitored.

The CEMP will contain specific sub-plans to minimise construction impacts, including:

  • construction noise and vibration with specific plans for night works
  • air quality, including dust
  • flora and fauna protection
  • water management.

The plans will define construction access and travel routes to minimise traffic and noise for local communities and businesses. Traffic management plans will be developed, implemented and monitored to manage the construction impacts of the project.

The T2D Project team will ensure a level of access, amenity and functionality for business and commercial sites. We will also give adequate notice for temporary access changes.