HS2 celebrates tunnelling breakthrough on Europe’s largest infrastructure project

HS2 Tunnel

Balfour Beatty VINCI, HS2, TBM, tunnelling, UK,

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Nearly 400 people working for HS2’s main works civils contractor Balfour Beatty VINCI (BBV JV) have delivered the first tunnelling breakthrough.

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

The giant 125m long TBM, which started its journey at the tunnel’s North Portal in December 2021, broke through the wall of the reception box at the South Portal site on Friday, 22 July. Nearly 400 people working for HS2’s main works civils contractor Balfour Beatty VINCI (BBV JV), have delivered this important milestone on the HS2 project.

The expert tunnelling team has been working around the clock in shifts for seven months to operate the TBM, which has put 790 concrete rings in place, each round made from eight two-metre-long segments.

“This milestone demonstrates the significant momentum behind Britain’s new zero-carbon railway, creating thousands of jobs and apprenticeships, along with hundreds of opportunities for businesses right across the country, helping fuel our economic recovery, says HS2 Ltd’s CEO Mark Thurston. 

The tunnel preserves the ancient woodland above, which is classified as a Site of Special Scientific Interest (SSSI) and has complex ecosystems that have taken hundreds of years to establish.

Creating both bores of the tunnel, the machine removes around 250,000 cubic metres of mudstone and soil, which is transported to the on-site slurry treatment plant, where the material is separated before being reused on embankments and landscaping along the route.

A 254 metres long conveyor at the north portal site, which takes the excavated material over the Grand Union Canal, removes the equivalent of around 30,000 HGVs from local roads, reducing impacts on the local community and cutting carbon.

“As Dorothy paves the way for journeys between Birmingham and London, we continue to strive towards delivering a greener, faster and more direct transport network. And as we deliver alongside our record-breaking Integrated Rail Plan, we’re boosting the economy, delivering over 25,000 jobs,” says HS2 Minister Trudy Harrison. 

Over the next four months, the cutter head and front section of the TBM will be dismantled and transferred back to the north portal, while the bulk of the machine will be brought back through the tunnel. It will be reassembled and ready to launch for the second bore of the tunnel.

Source: © High Speed Two Ltd 2022

Image source: © High Speed Two Ltd 2022

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