HS2 has confirmed that the western portal of the Copthall Green Tunnel has been completed. The tunnel, which is located in Hillingdon, Greater London sits between the twin-bored Northolt Tunnel.
Copthall Tunnel is one of five green tunnels on the HS2 route, which are shallower and designed to blend into the natural landscape.
So far, the western portal walls, spanning 110m have been completed, along with a further 240 metres of walls for the tunnel.
Malcolm Codling, HS2’s client director for the London Tunnels, said: “The Copthall Tunnel is a vital part of the HS2 route in Hillingdon and once complete.
“Our London tunnels contractor SCS JV is making great progress in its construction, all part of the momentum of HS2’s delivery between Old Oak Common and Birmingham.
“The Copthall Tunnel is a vital part of the HS2 route in Hillingdon and once complete will blend into the local landscape as one of HS2’s green tunnels. Our London tunnels contractor SCS JV is making great progress in its construction, all part of the momentum of HS2’s delivery between Old Oak Common and Birmingham.”
The tunnel is being constructed with reinforced concrete. Steel bars are tied and concrete poured around to form the strong box structure. To do this, the team initially excavated around 20 metres down from ground level, before installing piles for the foundations of the tunnel. The structure is then being constructed with a base slab, walls and a roof.
A 40 metre long temporary deck is positioned between the box walls and supported by moving gantry called a ‘roof traveller’. The roof traveller and deck temporarily support the construction and the pouring of the concrete roof. This is repeated until it is complete.
As part of the green tunnel design, HS2 will be using the material excavated on the surrounding landscapes with the intention of creating wildlife habitats.
Image: HS2 Ltd
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