Sunday, February 25, 2024

First look at Brisbane’s ‘missing link’ tunnel

Tunnelling works have commenced beneath Brisbane’s Adelaide Street, as part of the next stage of delivering the Brisbane Metro project.

Civic Cabinet Chair for Transport, Ryan Murphy said more than 170 piles had now been completed as part Brisbane Metro’s Adelaide Street tunnel.

“Brisbane Metro will deliver more travel options for people with a turn-up-and-go, fully electric transport network connecting the city to the suburbs,” Cr Murphy said.

“The 213-metre Adelaide Street tunnel will deliver a missing link in Brisbane’s public transport network, providing a direct dedicated connection between the South East Busway and the Inner Northern Busway for Brisbane Metro vehicles and buses.

“In Brisbane, two thirds of all public transport commuters travel by bus, which is why unclogging the bottlenecks in our bus network is so important.”

He said the tunnel will reduce the number of buses clogging CBD streets by up to a third, during morning and evening peak periods.

“The Adelaide Street Tunnel will run underneath one of Brisbane’s oldest streets, in amongst a complex network of utilities, services and heritage buildings, including Brisbane City Hall.”

“In some sections, the tunnel roof will be just three metres below the surface, with the deepest point seven metres underneath Adelaide Street.

“To protect the surrounding streetscape, we have employed a delicate and precise construction methodology that will see the tunnel excavated in three sections.”

There will be 16 Olympic swimming pools worth of soil and rock removed to deliver the 213-metre tunnel, connecting North Quay and the King George Square Bus Station.

A purpose-built drill rig is being used during construction to install over 20 kilometres of steel canopy tubes, which will help form the tunnel’s arched roof section.

“The Brisbane Metro project is using a highly advanced tunnelling method, compressing the time we’ll spend digging, from two and a half years to about 12 months,” Cr Murphy said.

“This is the first time in Australia that this tunnel construction methodology has been employed in an urban environment.

“This tunnelling solution was chosen to minimise disruption to businesses, pedestrians, and commuters along Adelaide Street.

“The alternative was to cut and cover, which would have caused the significant re-routing of buses, and resulted in adverse impacts to city businesses who are already doing it tough.” 

Work on the tunnel started in November 2021, with works in the past 12-months focusing on preparing the tunnel portal at North Quay.

Cr Murphy said there were around 115 people working on the tunnelling activities, while more than 2,600 jobs would be supported throughout the entire project. 

The works have uncovered several heritage artefacts, including bricks and bottles, and the perimeter of a convict-era stone wall, he said.

Some of the artefacts uncovered during project construction are now on display at the Brisbane Metro Information Centre at 63 Adelaide Street, where they can be viewed by the public.


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