HS2 has revealed the first images of innovative ‘green tunnels’ that will be built across Buckinghamshire and Northamptonshire, which will blend the new HS2 rail line into the natural landscape
The one-and-a-half-mile-long Greatworth green tunnel will be built in a factory in Derbyshire before being shipped to site, and assembled over the railway line as it passes the village.
The tunnel will then be covered with earth and landscaped to fit into the surrounding countryside.
Applying lessons from the construction of the latest French high-speed lines, an ‘off site’ modular approach was developed by HS2’s main works contractor, EKFB – a team made up of Eiffage, Kier, Ferrovial Construction, and BAM Nuttall.
The tunnel has been designed as an ‘m’ shaped double arch, and will have two separate halves for southbound and northbound trains.
Instead of the whole tunnel being cast on site, five different concrete precast segments will be slotted together to achieve the double arch.
All 5,400 segments installed at Greatworth will be steel-reinforced, with the largest weighing up to 43 tonnes.
As concrete and steel are some of the biggest sources of carbon emissions within the construction industry, HS2 have reduced the amount of materials needed for the tunnel.
This lighter-weight modular approach is expected to more than halve the amount of carbon embedded in the structure. It also requires less people and equipment on-site, improving safety and reducing disruption for residents.
