A major step forward in the construction of a tunnel being built near Chipping Warden in Northamptonshire took place when the last of the tunnel segments was lifted into place.
Chipping Warden is one and a half miles long and is a ‘green tunnel’, where the tunnel is built inside a cutting, and after construction has been completed, the earth is put back on top, which helps to blend the line into the landscape and reduces noise and disturbance.
The tunnel is HS2’s longest ‘cut and cover’ tunnel and consists of 5,020 reinforced concrete segments that form an ‘M’ shape, with separate halves for northbound and southbound trains. Now that all concrete segments are in place, work is continuing waterproofing, laying internal floor slabs, and emergency walkways alongside the track.
Forming a level base for the tunnel required the excavation of over two million cubic metres of material, which was stored on site and, after being compressed to equalise the weight distribution across the structure, is now being replaced on top of the structure. Final landscaping will include planting trees and restoring hedgerows.
Five other green tunnels are being built as part of HS2. Two of these, at Burton Green, in Warwickshire and Copthall, on the outskirts of London, are nearing completion, and tunnels at Wendover and Greatworth are being constructed with a similar pre-cast technique to Chipping Warden.
“It’s great to see the final segment slotted into position at Chipping Warden and I’d like to thank everyone who pulled together to find ways to optimise all the stages of construction – from excavation, tunnel construction, and backfilling. We’ve still got a long way to go, but with the tunnel precast structure complete, we can now focus on finishing the interior works and the earthworks and landscaping that will blend the railway into the surrounding countryside. Once complete, HS2 will become an integral part of the UK rail network, helping to improve journeys and free up space on the existing West Coast Main Line for more freight and local services.”
Sam Arrowsmith, Senior Project Manager, HS2 Ltd
Responses
Whilst this is impressive engineering, was a tunnel actually necessary? It is very shallow so surely a cutting would have been quicker and much cheaper.
I agree David.
All done to satisfy the NIMBY’s.
No the northern section of HS2 has been scrapped, HS2 is now pointless.
It’ll relieve the southern section on WCML, which is now so full that all applications to run additional services are being turned down by the regulator.