Tunnelling new connections – Infrastructure Magazine
The West Gate Tunnel Project is one of the major elements of Victoria’s Big Build. We check in on progress of the tunnels as the crew advances toward project completion by the end of 2025.
The West Gate Tunnel Project, part of Victoria’s Big Build, will deliver a vital alternative to the West Gate Bridge – one of Victoria’s busiest transport routes, carrying over 200,000 vehicles per day.
The project involves the construction of twin tunnels under Yarraville that will offer a vital alternative to the West Gate Bridge – removing over 9,000 trucks off inner west streets and giving drivers quicker trips to and from Melbourne’s west.
The twin tunnels will take traffic underground from the West Gate Freeway to the Maribyrnong River and on to an elevated road above Footscray Road.
Tunnelling on the West Gate Tunnel Project is now complete. The tunnels were built using two tunnel boring machines (TBMs) so that community and businesses could continue above ground while work happens below.
The project also involves widening the West Gate Freeway from eight to 12 through lanes to ease congestion, and support Victoria’s growing population.
Progressing the tunnels
There are more than 200 workers currently fitting out the tunnels with all the equipment needed to operate the tunnels safely.
This includes more than 1.1 million metres of cable, 26,000 metres of pipe for fire protection systems and more than 1,900 individual traffic speed and safety signs.
There will also be lights, traffic management systems, electrical wires and ventilation fans in place inside the tunnels.
The tunnels contain the latest in signalling and safety technologies and will link back to a purpose-built facility that will oversee the operation of the tunnel 24 hours a day, seven days a week.
The fit out of the tunnel safety and traffic management systems is more than halfway complete, with the final cable installation enough to stretch from Melbourne to Newcastle.
Excavation of the 31 connecting passages between the twin tunnels and maintenance levels was completed in late 2024, which will play a vital role in keeping the public safe in emergency situations.
The passages are 120 metres apart and connect the city and westbound tunnels, providing evacuation routes in the event of incidents.
The majority of the passages were excavated using the box jack technique, which involves pushing precast concrete structures into the ground using a high-powered hydraulic jack.
Seven of the passages were excavated using the latest geological technology to freeze the ground between the tunnels, ensuring the rock and soil in those passages remained stable while being dug out.
The ground freezing technique involves circulating liquid nitrogen through copper pipes drilled deep in the soil. This temporarily freezes any water content and increases the stability and strength of the earth, while the ground is kept frozen and waterproof until the concrete cross-passage structure is in place.
Utilising Intelligent Transport Systems
State-of-the-art smart technology will be installed across the length of the project linking it to other freeway management systems across Melbourne.
The system is a mix of:
- Lane use management signs
- Stop/go lights on freeway entry ramps
- CCTV cameras
- Travel time information signs
- Electronic variable message signs
- Automatic incident detection systems.
Freeway management systems help make journeys safer and travel times more reliable. They do this by controlling the flow of traffic both on and entering the freeway. The system also helps traffic better cope with accidents and breakdowns.
Aboveground progress
Aboveground, construction is forging ahead on the landmark architectural structures at the southern inbound and outbound tunnel portals, and the northern tunnel portal as part of the overall design features of the tunnel entry and exit points.
The heritage of the west is reflected in the design of the timber net structures, which have been inspired by the long maritime history associated with the area’s local waterways.
The installation of the steel frame that will wrap around the tunnel exit structure in South Kingsville is continuing, with installation underway of the external cladding.
Crews have installed the 195 elevated segments that form part of the new 2.5km veloway – a dedicated cycling path from Shepherd Bridge in Footscray to the city side of Moonee Ponds Creek.
Work is progressing on the installation of lighting, CCTV, handrails, non-slip surface and safety mesh covering to enable the veloway to be connected to the local cycling and walking path network later in 2025.
The veloway is part of over 14km of new and upgraded cycling paths delivered by the West Gate Tunnel Project, that will support the growing number of Melburnians riding to work each day.
There has been a major campaign of works this summer on the West Gate Freeway involving asphalting between the West Gate Bridge and Millers Road.
Once complete, four out of six lanes both inbound and outbound will be open with the lanes to exit and enter the tunnel remaining closed until project completion in late-2025.
The inbound express lanes will also be complete between the M80 Ring Road and the West Gate Bridge making travel easier.
Outlook for 2025
As the project progresses towards completion, it’s an inspiring time for everyone working on the West Gate Tunnel Project.
“We’re heading into our biggest and most exciting year as crews work above and below ground to put the finishing touches on this significant project,” said West Gate Tunnel Project Executive Director, Peter Lellyett.
“It’s exciting to see the finishing line, delivering the tunnels and new connections that will get over 9000 trucks off local streets in the inner west and give people a choice – the tunnel or the bridge.”
“I’m looking forward to seeing the benefits of the West Gate Tunnel Project realised when it opens by the end of this year.”
