Launched in November last year, it has only taken four months for the 2000t TBM to complete its one-mile second bore, making this the first complete twin-bore tunnel on the HS2 project.
After completing the first bore of the tunnel in July 2022, the 125m long TBM was dismantled and returned to the north portal, where it was reassembled, ready to start its second journey.
It's a huge achievement, not only for Balfour Beatty VINCI, but for everyone connected with HS2
Members of the Balfour Beatty VINCI tunnelling team were on site to witness the dramatic moment when the cutterhead broke through the reception box headwall. This marks the culmination of a three-year operation, from site set-up and TBM assembly, the first TBM drive and breakthrough, and now completing the second breakthrough.
David Speight, HS2's delivery director for Main Works Civils on Phase One, said: "I'd like to congratulate the 400-strong Balfour Beatty VINCI tunnelling team for achieving this fantastic milestone on the HS2 project. This is a key moment in HS2's operation in the Midlands, which is now reaching peak momentum with over 400 businesses in the region already winning work, and 9000 jobs supported.
"We're looking forward to celebrating more milestones as work gathers pace on key structures such as the Delta Junction viaducts, Birmingham Curzon Street station, Interchange station and Washwood Heath Depot, creating more opportunities for local businesses and people."
Michael Dyke, CEO for Balfour Beatty HS2 Major Projects, added: "Successfully completing the first twin-bore tunnel on Britain's new, highspeed railway is yet another demonstration of how works continue to progress at pace across the project. It's a huge achievement, not only for Balfour Beatty VINCI, but for everyone connected with HS2.
"Watching Dorothy break through her second one-mile journey today was only possible thanks to months of hard work and dedication from our 400-strong project team, who deserve a special mention for safely delivering this incredible feat of engineering."
The tunnelling team has been working around the clock in shifts for four months to operate the TBM, which has put 791 concrete rings in place, with each ring made from eight 2m-wide segments that each weigh up to 8t.
The tunnel, which preserves the ancient woodland above, forms a key element in how HS2 is managing environmental impacts through the design of the railway, protecting Britain's precious wildlife habitats. Long Itchington Wood is classified as a Site of Special Scientific Interest (SSSI) with complex ecosystems that have taken hundreds of years to establish.
Excavation of the twin-bore tunnel has produced around 500,000t of mudstone, which is being processed at an on-site slurry treatment plant. From there, it is separated out before being transported by a 254m conveyer to be used to build embankments along the route of the railway, removing the equivalent of around 30,000 HGVs from local roads, reducing impacts on the local community and cutting carbon.
Over the next few weeks, work will begin to dismantle the shield from the TBM, while the rest of the machine will be pulled back to the start of the tunnel and disassembled, ready for transportation to East Birmingham. There, the TBM will be fitted with a new shield so that it can begin a 3.5-mile tunnel bore in early 2024, between Water Orton in Warwickshire and Washwood Heath in Birmingham.
Got a story? Email: duncan.moore@aspermontmedia.com
