Structural work on the temporary pre-cast factory that will produce tunnel wall segments for HS2’s 10-mile-long Chiltern tunnels, has been completed at the south portal site, next to the M25.
All of the steel for the frame of the factory has been made in the UK and delivered by specialist steel fabricators, Caunton Engineering, from its base near Moregreen, Nottinghamshire. The same company will also deliver the steel for other temporary buildings, including a second precast plant that will be used to cast sections for the nearby Colne Valley Viaduct, the general warehouse, workshops and soil treatment plant. In total, around 2,400 tonnes of steelwork will be delivered to site from the former colliery site in Nottinghamshire.
The new tunnel segment 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 170-metre-long, 2,200 tonne machines will spend more than three years underground and use 112,000 concrete segments to line the tunnels, moving at a speed of 15.6 metres a day.
Once all the HS2 construction work is complete, the pre-cast plants will be disassembled and the whole site will be landscaped with material excavated from the tunnels and trees planted in order to blend it in with the surrounding countryside.
Welcoming the milestone, HS2’s C1 senior project manager, Mark Clapp said: “The pre-cast plant will play a crucial role in delivering the Chiltern tunnels. By casting all 112,000 segments on site, we can significantly reduce the number of HGVs on local roads, reducing disruption for the local community.
“I’d like to thank everyone at Align and especially Caunton for their hard work in making it happen. Caunton’s involvement shows how HS2 is delivering for companies right across Britain, creating jobs and helping the economy recover from the pandemic.”
Daniel Altier, Align’s project director, said: “Caunton Engineering is delivering the steel for all the structural buildings at our south portal site, 15 in total. This includes two tunnel pre-cast factories, the tunnel workshop and warehouse, and the viaduct precast factory. In selecting Caunton we opted for a company that can deliver a high quality product and value for money. The selection of key suppliers such as Caunton is essential in order that we can deliver the project on time and on budget.”