Contractor Skanska Costain STRABAG Joint Venture (SCS JV) has signed the first of two contracts for the production of concrete precast tunnel segments that will be used to construct HS2’s London tunnels.
Pacadar UK has been chosen to manufacture the tunnel lining in what will be the largest contract the company has ever delivered in the UK.
The company recently supplied tunnel segments for the Thames Tideway project and has the expertise to support SCS JV in delivering the London tunnels project.
Over 160,000 metres3 of concrete will be used to make the segments, which form a 9.5 metre outside diameter tunnel 0.35 metres thick. Each complete ring is made of seven segments and a key. Each segment weighs approximately 7t.
Production will begin at Pacadar UK’s factory in the Isle of Grain, Kent in January with the materials then delivered – by rail – to the launch site in West Ruislip. This is where the construction of the five-mile, twin-bored Northolt Tunnel West will begin.
They will be fitted to line the tunnel by the first two of six 2,600t tunnel boring machines (TBMs) currently under construction in Germany. The first will be delivered later this year and be assembled for launch in 2022.
The TBMs will operate non-stop for 22 months, only pausing for Christmas Day and other bank holidays.
“This is an important milestone in the programme as we get closer to launching our first two tunnel boring machines next year. We’re building 26 miles of twin bore tunnels, covering the 13 mile distance between West Ruislip and Euston, tunnelling up to 50 metres below ground.
“Using rail to deliver all our segments required for our tunnelling programme will help us to remove 1m lorry journeys from the road over the lifecycle of our programme.”
HS2’s London tunnels from West Ruislip to Euston station will have a total length of 26 miles, the same length as Crossrail.
Construction of the first tunnel is due for completion in 2024.
