Drilling begins on the first HS2 tunnel under Chiltern Hills

Drilling begins on the first HS2 tunnel under Chiltern Hills

Tunneling work is underway on the first section of the HS2 high-speed rail line which will link London and Birmingham.

The first of 10 huge tunnel boring machines (TBMs) began digging the first few meters of a 10 mile tunnel under the Chiltern Hills, just inside the M25 motorway in Hertfordshire.

The first machine, dubbed ‘Florence’ after nursing pioneer Florence Nightingale, works on the longest single tunnel on the route between the capital and the West Midlands. The excavation marks a key milestone for the railway, which is scheduled to enter service between 2029 and 2033.

Measuring 170 meters – the length of more than 15 London buses – and weighing over 2,000 tonnes, the tunnel boring machines were specially designed for the project.

Florence, and a second identical machine being assembled at the site near the M25, were shipped in thousands of pieces from manufacturer Herrenknecht’s plant in southwestern Germany.

The two tunnel boring machines will tunnel north and southbound HS2 trains, dig under the M25 and up to 90 meters below the Chilterns, and line the tunnel with concrete wall segments.

Segments for the tunnel walls and for the two-mile viaduct across the Colne Valley are being made on-site at HS2’s largest construction site, under a £ 1.6 billion contract for building just 15 miles of the 140 mile road between London and Birmingham. .

“It’s good for the economy,” said Mark Thurston, managing director of HS2, adding that the project would employ 16,000 people. “I hope the country will support this national enterprise. There is technology here that is at the cutting edge of technology in the world ”.

Engineers working near the front of the machine. Photographie: Martin Godwin / The Guardian

The tunnel boring machines excavating the chalk found under the Chilterns will operate around the clock for three years, progressing at about 15 meters per day. The extracted material is liquefied and rattling as it moves along the machine and out of the tunnel.

Described as a factory on the move, the TBMs are equipped with everything the 17 crewmembers might need during their 12-hour shift, including a washroom, a canteen with fridge and microwave, and two refuge rooms. , which would provide 24 hours of shelter. any emergency such as a fire.

“It’s like a submarine,” said Didier Jacques, the tunnel construction manager, who worked on the excavation of the Channel Tunnel three decades ago.

“It’s a combination of high-tech innovation, safety for people and a machine with all the new technologies.”

Anti-HS2 protests, such as those that began in January in the tunnel under Euston station, are considered unlikely at the tunnel site.

The future of the eastern section of HS2, from Birmingham to Leeds, remains uncertain, although HS2 Transport Minister Andrew Stephenson MP has said it will be part of the ‘integrated rail plan’ promised by the government.

Stephenson acknowledged that the high-speed rail “remains a controversial project,” but said railways are needed to meet the goal of net zero carbon emissions by 2050.

“We use advanced techniques to remove carbon from production, but it is also an electric railway. It’s much better than having people in cars. “


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