Preparations for the launch of HS2’s first giant TBM ramped up last week. The first of 112,000 segments for the Chiltern tunnel lining rolled off a purpose-built production line. The temporary pre-cast factory is situated next to the TBM launch pads near the future South portal of the tunnels, close to the M25. This will avoid putting extra HGVs on local roads and ensure a steady supply of segments for the TBMs.  

Once in the moulds the Steel Fibre Reinforced Concrete (SFRC) is polished by robots to improve the quality and consistency of the segments, and the final product.  A total of 160 rings, 7 segments each, will be produced ahead of launch of the first TBM.  

The assembly of the first two TBMs - named Florence and Cecilia – continues. They will be launched in early summer this year. Each of the 170m long, 2,000 t machines will dig on average 15 m a day, and will spend more than 3 years underground, digging and slotting the wall segments into place to create the 16 km (10 mile) long tunnels.   

Construction of the Chiltern tunnel, and nearby Colne Valley Viaduct, is being led by HS2’s main works contractor, Align JV - a joint venture made up of Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick.   

Click here for a video showing the start of production at the Chiltern tunnel pre-cast factory.  For further information on the project please click here and uk/65 for the tunnelbuilder archive. Visit https://www.hs2.org.uk/. 12/21.