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First tunnelling breakthrough on HS2

The TBM as it breaks through the wall of the reception box on the south side of the Long Itchington Wood tunnel on HS2.
BBV JV oversaw the first tunnelling breakthrough on HS2 (Image courtesy of HS2)

The Balfour Beatty Vinci joint venture (BBV JV) has overseen the first tunnelling breakthrough on HS2.

It took seven months to dig the first bore of the one-mile-long tunnel under Long Itchington Wood in Warwickshire.

The 125m-long tunnel boring machine (TBM) started its journey at the tunnel’s north portal in December 2021. The machine is named Dorothy after 1964 winner of the Nobel Prize in Chemistry Dorothy Hodgkin.

It broke through the wall of the reception box at the south portal side on 22 July.

Woodland preserved

BBV JV’s 400-strong team has worked around the clock in shifts for seven months to operate the TBM. The machine has put 790 concrete rings in place, with each ring made from eight 2m-long segments.

The tunnel preserves the ancient woodland above, a Site of Special Scientific Interest (SSSI) containing complex ecosystems.

BBV JV will now dismantle the cutterhead and front section of the TBM and transfer them back to the north portal. It will bring the bulk of the machine back through the tunnel to prepare for the second bore.

‘Historic moment’

HS2 Ltd’s CEO Mark Thurston said: “This is a historic moment for the HS2 project. And I’d like to congratulate everyone involved in delivering it. The 400-strong team, including tunnelling engineers, TBM operators and the construction workers at both portal sites, have pulled out all the stops to achieve this fantastic milestone.”

BBV JV’s managing director Michael Dyke said: “This is a momentous moment, not only for Balfour Beatty Vinci, but for everyone involved in delivering HS2. Thanks to the hard work and dedication of our team, Dorothy – our cutting-edge tunnel boring machine – has made history, becoming the first to safely and successfully breakthrough along the route.”

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