Hs2 hits milestone as TBM’s get to work

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Hs2 has hit a massive milestone with the two TBM’s Florence and Cecilia to start boring through the chiltern hills.

Ten huge giant tunnel boring machines (TBMs) will dig 64 miles of tunnels between London and the West Midlands in a major part of the Hs2 project.

Each TBM 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 15 meters a day.

HS2 will dig over 80 miles of tunnels, forming part of the HS2 network that will help connect the country, create thousands of jobs and rebalance the UK economy.

The massive machine which weighs 2,000-tonnes has been called the first Florence one of 10 that will dig 64 miles of tunnels between London and the West Midlands.

TBM's cutting teeth
TBM’s cutting teeth

Florence was named after Florence Nightingale , the huge TBM will dig the first of a pair of 10-mile long tunnels under the Chiltern hills and help to safeguard the woodland and wildlife habitats above ground.

Cecilia the second machine, named after pioneering astrophysicist Cecilia Payne-Gaposchkin, will launch next month to excavate the second tunnel at the South Portal site.

HS2 Chief Executive Mark Thurston commented saying that: “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.

“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.

“The start of tunnelling is a moment of genuine excitement for everyone involved, and I hope the entire country will get behind this truly transformative project.”

More than 16,000 jobs and over 500 apprenticeships are already being supported by the project.

The longest and deepest tunnel will be the Chiltern tunnel measuring at 10 miles (16km) long and will go as deep as 90 metres.

The London tunnels are 13 miles (21km), with a maximum depth of 50 metres. There will also be tunnels in the West Midlands, Buckinghamshireand Warwickshire and Northamptonshire.

In total 130 million tonnes of earth will be excavated, enough to fill Wembley Stadium 15 times!



A crew of 17 people will operate each TBM, working in shifts to keep the machines running 24/7. They will be supported by over 100 people on the surface, managing the logistics and maintaining the smooth progress of the tunnelling operation.

Designed specifically for the mix of chalk and flints under the Chilterns, the two identical TBMs will dig separate tunnels for north and southbound trains.

Each machine will travel at a speed of around 15 meters a day, digging and installing 56,000 precision engineered, fibre-reinforced segments, all being made on site.

The two TBMs will launch more than a month apart, but geological data fed back from Florence is expected to allow Cecilia to run slightly faster, meaning that they both break through at about the same time.

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 Project Director, Daniel Altier, said: “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.