Despite the pause on construction of High Speed 2’s (HS2’s) London terminus at Euston, work is progressing on tunnels to facilitate the work with the launch of the third HS2 tunnel boring machine (TBM) in London. The tunnel is not going to be used by HS2 trains though. It will instead be used as a logistics tunnel to deliver materials and remove spoil from the northern portal where HS2’s Euston twin bored tunnel will be constructed.
Engineers from HS2’s contractor, Skanska Costain Strabag joint venture (SCS JV), launched the 847t TBM from the Atlas Road site in North Acton. It is from that point where an 853m tunnel to the Old Oak Common Station site will be built. The tunnel drive is set to be completed in “around six months”, according to HS2. It will be constructed using 4,264 concrete segments forming 533 tunnel rings. The segments, each weighing more than three tonnes, have been produced by Pacadar in Kent.
A conveyor system is also going to run through the logistics tunnel. It will connect to an existing conveyor at Atlas Road, taking the London clay being excavated to construct the Euston Tunnel to HS2 London Logistics Hub at Willesden Euro Terminal. The spoil will be taken from there by train for re-use at sites in Kent, Cambridgeshire and Rugby.
The TBM being used to construct the tunnel has been repurposed using components from a TBM – known as Jessica – that had previously been used on the Crossrail project. The TBM dug two sections of the Crossrail tunnels in London – from Limmo Peninsula in Canning Town to Royal Victoria Dock, and between Pudding Mill Lane and Stepney Green – boring a total of 3.5km.
TBM manufacturer Herrenknecht designed a TBM specifically for HS2’s requirements and has remanufactured components including the shield and the cutting wheel.
SCS managing director James Richardson said: ”This is our third TBM to launch in London and later this year we will have five machines operating. Four of these will be boring the HS2 tunnels, linking West Ruislip and Old Common. “This launch is significant as it is not used for the operational railways, but will create a direct link to between our logistics hub and Old Oak Common, allowing us to transport tunnel segments and spoil without using local roads.”
HS2’s project client for the London tunnels Malcolm Codling added: “The Atlas Road Logistics Tunnel is key to how we will be constructing the Euston Tunnel between Old Oak Common and HS2’s Euston station. The logistics tunnel allows us to take 70,000 lorry journeys off the local roads that would otherwise have been required and will reduce the impact of HS2’s construction on the local community.”