HS2 has passed another major milestone at the high speed rail project’s first tunnel site, with the completion of structural work on the temporary pre-cast factory which will produce wall sections for the 10 mile long Chiltern tunnels.
The tunnel precast factory – and all 2,400 tonnes of structural steelwork at the south portal site, next to the M25 – will be made in the UK and delivered by specialist steel fabricators, Caunton Engineering, from their base near Moorgreen, Nottinghamshire.
The factory will allow HS2’s main works contractor, Align JV – a joint venture made up of three companies: Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick – to cast all the tunnel segments on-site and avoid putting extra HGVs onto local roads.
Two giant tunnelling machines – named Florence and Cecilia – are due to launch next year.
The 170m long, 2,200-tonne machines will spend more than 3 years underground and use 112,000 concrete segments to line the tunnels, moving at a speed of 15.6m a day.
A second precast plant will be used to cast sections for the nearby Colne Valley Viaduct.