HS2 Ltd has launched the first of 10 Tunnel Boring Machines (TBMs) to dig 103km of tunnels for Phase One of the high-speed line from London to Birmingham.
The 2000-tonne TBM, named Florence after British nursing pioneer Florence Nightingale, was launched from HS2’s South Portal site next to the M25 highway in Buckinghamshire, and will dig the first of two 16km-long tunnels beneath the Chiltern hills to help safeguard the woodland and wildlife habitats above ground. A second machine, named Cecilia, will launch at the South Portal site next month to excavate the second tunnel.
The first two TBMs will be operated by the Align joint venture, formed of international infrastructure companies Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick.
The TBMs are designed specifically for the mix of chalk and flints under the Chilterns, and were built by Herrenknecht at its factory in south-west Germany. The two 170m-long machines were transported to Britain in more than 300 separate shipments last year, before being reassembled, tested and commissioned by an expert team of tunnelling engineers at the Chiltern tunnel south portal site.
Each machine operates as a self-contained underground factory, digging the tunnel, lining it with concrete wall segments and grouting them into place at a speed of around 15m a day. Each tunnel will require 56,000 precision engineered, fibre-reinforced segments, which will all be made on site.
“The TBMs include a number of innovations to improve efficiency and the safety of the environment in which the crew will be working, that have never before been introduced on any previous TBMs, worldwide,” says Align project director, Mr Daniel Altier.
A crew of 17 people will operate each TBM, working in shifts to keep the machines continuously running 24 hours a day. They will be supported by over 100 people on the surface, managing the logistics and maintaining the smooth progress of the tunnelling operation.
Chalk excavated from the tunnels will be used for landscaping at the south portal site once construction is complete, creating wildlife-rich chalk grassland habitats across 127 hectares of the southern Chiltern hills.
Align is recruiting 1200 staff in total, including 100 apprentices, to work on the Central 1 Area of HS2 Phase One that it is delivering.
Construction of the 225km Phase 1 from London to Birmingham and Lichfield formally began in September 2020, after the project was approved by parliament in February 2020. The 60km Phase 2a, which will run from the northern end of Phase 1 at Fradley in the West Midlands to Crewe in Cheshire, received royal assent in February.
The launched was attended by HS2 minister, Mr Andrew Stephenson, and HS2 Ltd CEO, Mr Mark Thurston, and other dignitaries.
“The launch of our first tunnelling machine is a major moment of progress for the HS2 project as we work to deliver a high-speed railway that will offer low-carbon alternatives for long distance journeys across the UK,” Thurston says. “With more than 16,000 jobs already supported by the project and thousands of companies big and small benefiting from contracts, HS2 is providing a major boost to the economy in these difficult times.”
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