News on HS2 in Bucks & Oxfordshire

The first of five headhouses that will provide ventilation and emergency access to HS2’s ten-mile long Chiltern tunnel has gained planning approval from Buckinghamshire Council.

We engaged with the Chilterns AONB Review Group and Buckinghamshire Council during the development of the designs for the Chalfont St Peter headhouse and held a series of public engagement events to gather views from the local community.

The Chalfont St Peter headhouse is designed to fit into the surrounding landscape, taking its inspiration from the style of nearby barns and other agricultural buildings. Set back from the road, the single-story building will be wrapped in a simple grey zinc roof with doors and vent openings picked out in a dark bronze colour to provide contrast.

The pre-weathered grey zinc roof will age naturally over time, without loss of robustness or quality, while the whole structure will sit on a simple dark blue brick base. Below ground level, a 78 metre ventilation shaft will reach down to the twin tunnels below, with fans and other equipment designed to regulate air quality and temperature, remove smoke in the event of a fire and provide access for the emergency services.

Mature trees along the existing boundary will be retained as far as possible and once construction is complete the whole site will be landscaped with new trees and hedgerows to help screen the site from neighbouring properties. Within the site boundaries, species-rich grassland habitats will be created, designed to further blend the site into the surrounding Chiltern Hills. Material excavated from the shaft will also be used to create much of the landscaping and avoid putting extra lorries onto local roads.

A temporary access road has already been completed to link the site with the A413, Amersham Road. This allows construction traffic to avoid the centre of Chalfont St Peter and stop heavy goods vehicles (HGVs) driving past Robertswood School and the Epilepsy Society. A new temporary marshalled lorry holding area has also been established on the A413 near Gerrards Cross where HGVs can be held until their approach to the vent shaft site is clear, helping to reduce congestion and eliminate queueing at the site entrance.

The plans were drawn up by our main works contractor Align JV (Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick, working with its design partners Jacobs and Ingerop-Rendel, the architect Grimshaw and landscape designers, LDA).

If you have a question about HS2 or our works, please contact our HS2 Helpdesk team on 08081 434 434 or email hs2enquiries@hs2.org.uk .