First tunnel breakthrough on HS2


A 2,000 tonne tunnel boring machine named ‘Dorothy’ – named after Dorothy Hodgkin, who in 1964 became the first British woman to win the Nobel Prize in Chemistry – has completed its one-mile excavation under Long Itchington Wood in Warwickshire.

The 125m-long tunnel boring machine began its journey at the north portal of the tunnel in December 2021 and broke through the wall of the reception box at the site of the south portal on Friday.

Nearly 400 people working for the civil engineering company Balfour Beatty VINCI (BBV JV) of HS2 achieved this important milestone in the project.

The team of tunneling experts worked around the clock in shifts for seven months to operate the tunnel boring machine, which placed 790 concrete rings in place, each ring made up of eight two-meter-long segments.

HS2 Ltd CEO Mark Thurston said: “This is a historic moment for the HS2 project, and I would like to congratulate everyone involved in bringing it to fruition. The 400-person team, made up of TBM engineers, TBM operators and construction workers at the two portal sites, pulled out all the stops to achieve this fantastic milestone.

“This milestone demonstrates the significant momentum behind Britain’s new zero-carbon railway, creating thousands of jobs and internships, as well as hundreds of opportunities for businesses across the country, helping to fuel our economic recovery. “

Celebrating the breakthrough with his team, Balfour Beatty VINCI Managing Director Michael Dyke said: “This is a momentous moment, not just for Balfour Beatty VINCI, but for everyone involved in delivering HS2.

“Thanks to the hard work and dedication of our team, Dorothy – our state-of-the-art tunnel boring machine – has made history, becoming the first to safely and successfully drill along the road.

“With Dorothy’s journey now complete, I look forward to celebrating even more milestones throughout the year and beyond as we continue to help build Europe’s biggest infrastructure project.”

In creating the two bores of the tunnel, the machine removes approximately 250,000 cubic meters of mudstone and earth, which is transported to the on-site sludge treatment plant where the material is separated before being reused on embankments and l landscaping along the route.

A 254-meter-long conveyor at the North Portal site, which transports excavated material over the Grand Union Canal, removes the equivalent of approximately 30,000 heavy goods vehicles from local roads, reducing impacts on the local community and reducing carbon emissions.

Over the next four months, the cutting head and the front part of the tunnel boring machine will be dismantled and transferred to the north portal, while the bulk of the machine will be brought back through the tunnel. It will be reassembled, ready to be launched for the second drilling of the tunnel.


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