HS2 has announced a significant milestone at Long Itchington Wood tunnel in Warwickshire – the first deep tunnel on the high-speed route to complete its civil engineering phase.
A dedicated workforce of around 380 people have worked over the past five years to reach this latest phase of construction, where the 1.61 km (one-mile) twin-bore tunnel – which will carry the railway into the West Midlands –is now fitted with three cross-passages and the concrete finishing works, base slabs, and walkways are also complete. A total of 1,582 concrete rings have been installed across both tunnels, with each ring made from eight 2 m-wide segments, each weighing up to 8 t.
It comes before the internal fitting out of the tunnel with the complex systems needed to operate the high-speed line including the power, track and signalling.
The Long Itchington Wood tunnel is the first of five twin-bore tunnels on the HS2 project to reach this vital stage. The four other twin bore tunnels on HS2 are:
- the 5.63 km (3.5-mile) Bromford Tunnel which carries the railway into Birmingham, with both tunnel drives expected to be completed this year.
- the 16.09 km (10-mile) long Chiltern Tunnel – HS2’s longest, which takes the railway beneath the Chiltern Hills – with both tunnel drives being completed in early 2024 and internal works on the tunnels now ongoing;
- the Northolt Tunnel – an 13.52 km (8.4-mile) tunnel between Old Oak Common and outer London – which is being built by four tunnelling machines, with the first drive completed in December last year;
- the 7.24 km (4.5-mile) Euston Tunnel between Old Oak Common and central London which is at an advanced preparation stage before the launch of two tunnel boring machines.
In all, 44.09 km (27.4 miles) of the route between London and the West Midlands are in deep, twin-bore tunnels.
Work to create the Long Itchington Wood tunnel initially began in June 2020. The 125-mlong TBM used to excavate the tunnel was named Dorothy – after Dorothy Hodgkin who was the first British woman to win the Nobel Prize in Chemistry. The machine was launched in December 2021 and finished excavating both bores of the tunnel by March 2023.
The complex process to fully excavate two tunnel drives and the entrance sections produced around 750,000 t of material, which has since been reused to build embankments along the route of the railway. Since the breakthrough almost two years’ ago, work has been ongoing to fit out the tunnels with its vital structural components.
The tunnel is being built by HS2’s main works contractor for the West Midlands, Balfour Beatty VINCI (BBV), which is constructing 90 km (56 miles) of HS2 between Long Itchington in Warwickshire to the centre of Birmingham and on to Staffordshire.
Long Itchington Wood Tunnel has been designed to minimise the impact of construction, with local land topography a key factor in the design and delivery process. At 30 m below ground level, the tunnel preserves an ancient woodland above and avoids local villages.
When complete, HS2 services will run between London and the West Midlands on a dedicated high-speed line before reaching destinations further north – creating economic growth and freeing up space for more local trains on the most congested part of the existing West Coast Main Line.
For further information click here for a video, here and uk/65 for tunnelbuilder archive. Visit https://www.hs2.org.uk/. 09/25.
