By Lynda Myer
TBM Florence, which has 2,000-ton weight, was launched from HS2’s South Portal site next to the M25 in Buckinghamshire by HS2 Ltd on 13 May 2021. It’s the first of 10 TBMs that will collectively dig 103 km (64 miles) of tunnels between London and the West Midlands. The new high-speed railway will present low-carbon alternatives for long distance journeys across the UK.
The intended schedule for this170m-long TBM is three years of operating around the clock to excavate the first of a pair of tunnels with16 km (10 miles) length beneath the Chiltern hills and the second tunnel at the South Portal site will be excavated by Cecilia, the second TBM, next month.
The Algin, which is HS2’S main works contractor and a joint venture formed of three international infrastructure companies: Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick, will manage working with first two TBMs, which are designed specifically by Herrenknecht for the mix of chalk and flints under the Chilterns.
Every machine acts as an independent underground factory – excavating the tunnel, lining it with concrete wall segments and grouting them into place at a speed of almost15 m per a day. Each tunnel will require 56,000 fiber-reinforced segments – which will all be made on site.
In order to creating wildlife-rich chalk grassland habitats across 127 hectares of the southern Chiltern hills, Chalk excavated from the tunnels will be used for landscaping at the south portal site following the construction is complete.
The two TBMs have been named by students at Meadow High School in Hillingdon and The Chalfonts Community College, Buckinghamshire, which are close to the tunnel launch site. They were inspired by Florence Nightingale, the founder of modern medicine, and pioneering astronomer and astrophysicist, Cecilia Payne-Gaposchkin. According to the voting results from almost 4,500 people from across the UK to select the final names, Florence taking 40% of the vote and Cecilia a close second with 32%.
For further information on this project please click here for tunnelingworld archive and also visit this website.
