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WestConnex M4-M8 Link Tunnels project

2024 National Infrastructure Awards Finalist

WestConnex M4-M8 Link Tunnels project


WestConnex M4-M8 Link Tunnels project

The $3.2 billion WestConnex M4-M8 link project saw the delivery of a new twin tunnel system linking the existing M4 motorway at Haberfield to the M8 motorway at St Peters. The project features 7.5 kilometre-long mainline tunnels, reaching an average depth of 35 metres beneath the surface, and forming a continuous 33 kilometre-motorway network across Sydney. The tunnels have a 100-year design life and have connections in place to other major projects including Rozelle Interchange, Sydney Airport and a further connection to the south via the M6 tunnels. A key deliverable of the project, 28 road-headers were used during tunnelling, with 8.7 million tonnes of spoil removed from site and beneficially re-used – including at Western Sydney Airport. 

It was clear to the Judging Panel in considering this project’s shortlisting in both the Contractor Excellence and the Government Partnerships Excellence Award categories that this project was a candidate for Project of the Year. Not only was it delivered ahead of schedule and on budget, but it has set a world-leading benchmark for connecting infrastructure assets and had a transformative impact on Sydney’s transport network. The project has achieved significant sustainability standards, including a 42 per cent reduction in Scope 1 & 2 emissions during construction and a 63 per cent reduction over the design life. The Panel also praised the use of an Operational Management Control System, which allows for the coordinated operation of the two motorways and link tunnel by centralising control functionalities, resulting in efficient operations of the three connected projects.