The New South Wales and Federal Governments have partnered with Transurban to deliver NorthConnex, a $3 billion ‘missing link’ connecting the M1 and M2 motorways in Sydney’s north via twin 9km tunnels. 

Construction work has been carried out by the Lendlease Bouygues Joint Venture since 2015 and the project is expected to be completed in the third quarter of 2020.

A Transport for New South Wales spokesperson said, “When the tunnels open, they will allow motorists to bypass 21 sets of traffic lights along Pennant Hills Road, which is one of the most congested road corridors in Australia. 

“NorthConnex will also allow motorists to drive from Newcastle to Melbourne without passing a single set of traffic lights.

“The tunnels have been future-proofed, built wide enough for three lanes in each direction, initially operating with two lanes and a breakdown lane in each direction.”

The spokesperson said more than 100,000 vehicles per day will be able to travel on the tunnels, saving motorists around 15 minutes travel time.

“NorthConnex is Australia’s deepest road tunnel and an engineering marvel, with careful planning required to excavate underneath three train lines including the new Metro North West Line,” the spokesperson said.

At the deepest point the tunnel is 90m – or around 27 storeys below the surface – with an average depth of 60m.

Four specially designed vertical conveyors located at each of the four tunnelling shafts were used to transport excavated spoil to the surface. This methodology removed the need to build tunnel dives into the mainline tunnels and helped reduce the project footprint within the local community.

Innovative spoil excavation

Around 2.3 million cubic metres of spoil has been excavated by 20 roadheaders and two surface miners which carved through around 21km of mainline tunnels over a two and a half year period. 

“Designed and built by Sandvik and Mitsui, they weighed around 100 tonnes and ‘chewed’ through roughly 25m of rock per week,” the spokesperson said.

“More than one million cubic metres of the spoil excavated for the project was used to partially fill the nearby Hornsby Quarry, laying the foundations to transform the site into a future parkland for the local community.

“In an Australian first, conveyors reaching 160m in length were used to transport the spoil into the quarry, at a rate of up to 2,000 tonnes of spoil per hour. This process helped to significantly reduce truck movements in the local area and minimise impact on the surrounding environment.

“Spoil from the project was also transported for reuse at residential and other development project sites across Sydney.”

Constructing the tunnel

The main type of primary tunnel supports on the project consist of a thin layer of shotcrete and rock bolts. Approximately 300,000 rock bolts up to 5m in length have been installed to support the tunnel’s structure.

More than 122,000 truck-loads of concrete have been poured for the tunnels’ final lining and pavement.

“The continuous reinforced concrete pavement is 25cm thick and able to withstand the up to 5,000 trucks that will be using the NorthConnex tunnel every day,” the spokesperson said.

NorthConnex Project Company, Project Director, Dan Banovic, said, “Since construction first began more than five years ago, more than 17,000 people have worked to deliver NorthConnex.

“We’re nearing completion and on the home stretch now with operational systems testing and commissioning activities under way.

Powered by locals

“Many local businesses and suppliers have contributed to the delivery of NorthConnex, which has provided an economic boost across Greater Western Sydney and the Central Coast regions.” 

Mr Banovic said more than 1,500 workers from the Central Coast, across more than 50 businesses, contributed to the project, demonstrating the region’s strong involvement in the project. 

“This is just one region which is benefiting from the 8,700 jobs being created across the state thanks to NorthConnex,” Mr Banovic said.

“More than 230 businesses from the Greater Western Sydney area have also contributed to the project, highlighting the opportunities this project has created for local suppliers and contractors. 

“We’re proud to deliver this project for New South Wales which will be used for generations to come.”

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