Skanska Costain JV signs deal on HS2 TBMs

The Skanska Costain Strabag (SCS) joint venture has signed a contract for two huge tunnel boring machines (TBMs) that will be used to bore through London clay and chalk for the construction of the southern stretch of the high-speed line.

The TBMs are being built by manufacturer Herrenknecht and
will be delivered to site by the end of 2021.

The London tunnels for HS2 are twin bored and will be 13
miles each way. The project will involve tunnelling between central London and the
M25.

The two TBMs will be launched from a portal at West Ruislip and will travel five miles east, creating the western section of the Northolt tunnel. Once they arrive at Green Park Way in Greenford, the machines will be extracted from the ground and the site will then be used as a vent shaft. The 8.4-mile tunnel will be completed with a 3.4-mile tunnel drive from Old Oak Common using two further TBMs which are yet to be procured. A second tunnel between Euston and Old Oak Common will complete the remaining 4.5 miles of London tunnel between the two HS2 stations.

Once the first new TBMs have been built, they will be
transported by sea before being delivered to site at the end of 2021. Once
assembled, they will begin the tunnel drive from mid-2022, until completion at
the beginning of 2024.

Each 140m-long, 2,050t machine will run for 22 months
non-stop except for Christmas day and bank holidays. The cutter head will be
9.84m in diameter, slightly smaller than the machines boring through the
Chilterns.

Overall, there will be 10 TBMs purchased to construct 64
miles of tunnelling along the HS2 route between the West Midlands and London.

James Richardson, managing director of Skanska Costain Strabag
joint venture (SCS JV) said: “As the construction partner responsible for the
majority of tunnels on the HS2 project, our contract for the first two TBMs is
a major milestone for us. This partnership with Herrenknecht has brought
together leading expertise in both our organisations and together we are
constructing some of the most advanced TBMs in the world to efficiently drive
the tunnels under London.

“Work is already well underway to prepare for the first
tunnel launch in 2022. Throughout these and all our activities we are committed
to involving local communities and stakeholders and supporting social
development and employment through the 4,500 jobs that will be created.”

Malcolm Codling, client director at HS2 Ltd, said: “HS2’s
London tunnels will help ensure many homes and habitats in the capital remain
undisturbed. This is a key part of our commitment to deliver Britain’s new high-speed
railway in the most environmentally-friendly way and minimising disruption to
our neighbours.

“Building HS2 will showcase Britain’s world class
capabilities in tunnelling. The procurement of these incredible machines is an
exciting step towards the construction of the London tunnels, which will
involve them working 24 hours a day, seven days a week.”