Keltbray has won a contract to deliver construction services for the first two ventilation shafts and head houses on the Chiltern Tunnels section for HS2. These are shafts located at Chalfont St Peter and Chalfont St Giles.
The work is being carried out for the Align Joint Venture (Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick) that is delivering the Central 1 portion of HS2 Phase 1.
These shafts will provide both ventilation and access to a ten-mile tunnel being dug by Align under the Chiltern Hills.
Keltbray’s scope will include:
- 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.
So far, excavation of the first shaft to 78 metres, close to Chalfont St Peter village, has been finished, ahead of Keltbray carrying out its work.
Once construction is complete, the shaft will be topped by a head house taking design cues from nearby barns and other agricultural buildings to better integrate it with the area.
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.
Director of strategic engineering at Keltbray, Tim Lohmann, 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.”