Ground freezing technology to be deployed on Suburban Rail Loop tunnels

Ground freezing technology and boring machines moving in opposite directions will be deployed on the first stage of the $35bn rail project, building twin tunnels between Cheltenham and Glen Waverley.

Ground freezing technology will be used to build 55 safety passages between twin tunnels of the $35bn Suburban Rail Loop East.

The construction method, used to stabilise material that is being excavated deep underground, drills a series of pipes into the soil and pumps them with chilled brine — a mix of salt and water.

Most of the stabilisation will be done by while workers deep underground within the core tunnels, which the project builders say will minimise impacts on local roads and homes in Cheltenham, Heatherton and Clayton South.

The Herald Sun can also reveal more details of how 16km of twin tunnels would be built between Cheltenham and Glen Waverley, as part of the first major SRL East contract, signed this month for $3.6bn.

What the Suburban Rail Loop is expected to look like. Picture: Supplied

Suburban Rail Loop map Supplied

Boring machines will set off in two directions from a planned stabling facility in Heatherton, with operators digging towards Glen Waverley to the east, and Cheltenham to the west.

A contract for the remaining 10km of the SRL East, between Glen Waverley and Box Hill, will be negotiated next year.

Tunnels for the new rail line will be 6.4m wide, with custom-built and “fully automated” or driverless trains designed to fit that space.

Transport Infrastructure Minister Danny Pearson said the SRL East, which would link Cheltenham to Box Hill once built along with six new underground stations, would leave a lasting legacy, with 12 per cent of hours to be done by apprentices, trainees and cadets.

“We are getting on with building the Suburban Rail Loop, which will deliver the longest rail tunnel in Australia — while creating 8,000 new jobs and slashing travel times,” he said.

What the planned Box Hill station is expected to look like. Picture: Supplied

The projects first tunnels will run between Cheltenham and Glen Waverley. Picture: Supplied

Two groups of rail and construction giants have been short-listed to build the trains and operate the network, which is referred to as the Linewide Alliance package, and which is set to be contracted in 2025.

A group called TransitLinX is made up of John Holland, RATP Dev, Alstom, KBR and WSP.

The second group called UrbanLeap is made up of Gamuda Engineering, Keolis Downer, Siemens, AECOM, GHD, Hyundai Rotem and Downer Rail.

The signing of the first major contract for the SRL East sparked debate due to concerns about a shortfall of funding for the project, and Victoria’s spiralling debt levels.

Days after the $3.6bn contract was awarded, Premier Jacinta Allan revealed a separate project — the North East Link toll road and tunnel — had blown out by an incredible $10bn.

When announcing the SRL East contract, Ms Allan said she stood by the budget estimate of $30-34.5bn set for the 26km project in 2021.

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