Kelbray is now working on behalf of the Align Joint Venture of Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick delivering the Central 1 portion of HS2 Phase 1.

The shafts will provide ventilation and emergency access to the ten-mile long tunnels Align is digging under the Chiltern Hills. 

Keltbray will provide:

• Reinforced concrete works at the base of the shafts, to create a collar structure to enable the TBMs to pass through the base of the shaft
• Internal shaft construction works to build slip-formed concrete cores and lining walls
• Excavation and substructure construction of Head House buildings

Excavation of the first shaft to a depth of 78m located close to the village of Chalfont St Peter has already been completed, ready for Keltbray to start work.

After the construction is complete the shaft will be topped with a head house inspired by nearby barns and other agricultural buildings to help it fit into the surrounding landscape.

Below ground level, the shaft will reach down to the twin tunnels, with fans and other equipment designed to regulate air quality and temperature, remove smoke in the event of a fire, and provide access for maintenance and emergency services.

Tim Lohmann, Director of Strategic Engineering at Keltbray, said: “Keltbray is delighted to have secured this major package of rail infrastructure works with the Align JV to deliver on this important opportunity for HS2.

“The tunnels form part of the HS2 network that will help connect the country, create thousands of jobs and rebalance the UK economy. We’re delighted to be involved in such a historic project.”