By Ashley Karen
Keltbray, the specialist engineering company has received a contract with HS2 (High Speed 2) Align JV, the main works contractor, to deliver essential structural elements of the first two ventilation shafts for the Chiltern tunnels section.
This firm is going to provide construction services for the first two ventilation shafts and headhouses on HS2’s two tunnel drives at Chalfont St Peter and Chalfont St Giles. Keltbray will do the work on behalf of Align (a JV between Volker Fitzpatrick, Bouygues Travaux Publics, and Sir Robert McAlpine) that is delivering the Central 1 portion of HS2 phase one.
The shafts sought to supply ventilation and emergency access to the 16km long tunnels Align is excavating under the Chiltern Hills.
Keltbray’s scope of works will cover:
- Reinforced concrete works at the base of the shafts to make a collar structure to allow the TBMs (tunnel boring machines) to pass through the base of the shaft
- Internal shaft construction works to construct slip-formed concrete cores and lining walls
- Boring and substructure construction of headhouse buildings
Already, Align has finished boring of the first shaft, placed close to the village of Chalfont St Peter, to a depth of 78m, which means that Keltbray can get to work there. After completing the construction, the shaft is going to be topped with a headhouse inspired by nearby barns and other agricultural buildings to assist it to fit into the surrounding landscape.
Under the ground level, the shaft will go down to the twin tunnels, with fans and other equipment designed to regulate temperature and air quality, clear smoke in the event of a fire, and provide access for maintenance and emergency services.
“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,” stated Tim Lohmann, Keltbray director of strategic engineering.
He also asserted: “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.”
