The first of two tunnel boring machines has excavated the first kilometre of the North East Link tunnels from Watsonia to Bulleen.
The tunnel boring machines (TBMs) – named TBM Zelda and TBM Gillian – were launched earlier this year and are on their way through digging the 6.5-kilometre tunnels.
TBM Zelda is excavating the northbound tunnel and has completed the 1000 metre milestone, while TBM Gillian has just passed 700 metres on the southbound tunnel.
As they move forward, both machines are installing concrete segments made locally in Benalla. Concrete culverts made in Echuca are also being installed behind each TBM to form a service route for maintenance vehicles inside the tunnels.
Next year the TBMs will break through near Lower Plenty Road where on and off ramps are being built, before they relaunch underground and continue their journey towards Bulleen.
In the southern section of the North East Link tunnels, mined tunnelling is underway between Manningham Road and Trinity Grammar, with five large road headers chipping away at the rock layer deep underground and spraying concrete to support the roof and sides of the tunnel.
Tunnelling will be up to 45 metres underground to build the road that will pass traffic under instead of through local suburbs.
The tunnels are also being built using 100 per cent renewable electricity, and dirt and rock from construction is being re-used across North East Link and other transport sites where possible.