Balfour Beatty VINCI has announced a significant milestone at HS2’s Long Itchington Wood Tunnel in Warwickshire – the first deep tunnel on the high-speed route to complete its civil engineering phase. The development at the one-mile-long twin-bore tunnel – which will carry the railway into the West Midlands – sees vital elements, including three cross passages, concrete finishing works and base slabs, and emergency and maintenance walkways complete. 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 tunnel is the first of five twin-bore tunnels on the HS2 project to reach this vital stage. In all, 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-metre-long tunnel boring machine 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 tonnes 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, which is constructing 56 miles of HS2 between Long Itchington in Warwickshire to the centre of Birmingham and on to Staffordshire. Jules Arlaud, Tunnelling Director for Balfour Beatty VINCI, said: “The scale of this achievement is enormous. A dedicated workforce of around 380 people have worked tirelessly over the past five years to reach this latest phase of construction, where the tunnels are now fitted with three cross-passages and the concrete finishing works, base slabs, and walkways are also complete. “Throughout this project, our expert tunnelling team have installed a total of 1,582 concrete rings across both tunnels, with each ring made from eight two-metre-wide segments, each weighing up to 8 tonnes.” Doug Barnett, Senior Project Manager for HS2 Ltd, said: “It’s a small part of HS2 but it’s been four and a half years of my life in which I’ve seen this construction go from its very embers to nearing completion – a really proud moment for me personally. “Long Itchington Wood Tunnel is a tremendous feat of engineering and would not have been possible without a huge amount of continuous work put in over the past five years – I’d like to thank everyone involved working both onsite and behind the scenes for their support.” In total, 380 people have supported the Long Itchington Wood tunnelling project since construction work began. This includes recent engineering graduate Alfie Ward who used his new-found design knowledge and surveying skills to help HS2 engineers successfully complete the tunnel’s cross passage work safely and efficiently. Alfie Ward, Engineering Graduate at Balfour Beatty VINCI, said: “Working as a young engineering graduate on the Long Itchington Wood Tunnel was the perfect platform to launch my career from. This experience at such an early stage in my career meant I was able to learn lots of new skills, which I’m now applying at Bromford Tunnel, as a site engineer.” 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 metres below ground level, the tunnel preserves an ancient woodland above and avoids local villages. Construction of HS2 continues between the West Midlands and London, with the programme now supporting over 31,000 jobs. 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. In recent weeks, construction progress in the West Midlands has seen HS2 complete its first viaduct at HS2’s Delta Junction in North Warwickshire. HS2 has also revealed the latest progress on a new green bridge set to cross the high-speed railway near Kenilworth, Warwickshire. Building, Design & Construction Magazine | The Choice of Industry Professionals