The first two Earth pressure balance tunnel boring machines (TBM) arrived on site for the HS2 London Tunnel program. The Herrenknecht TBMs were delivered to HS2’s Main Work’s Civils Contractor, Skanska Costain STRABAG joint venture (SCS JV).
The start of tunneling works is expected to begin in 2022.
The two machines will be the first of six TBMs that will bore 21 km (13 miles) of twin bored tunnels underneath London where HS2 services will run. They will join eight other machines that will operate on Phase One of the HS2 project between London and the West Midlands, which will dig 103 km (64 miles) of tunnels in total.
Getting the huge pieces of the TBM to site required a huge amount of logistical coordination, with support from the police and National Highways. The largest components of the machines were transported by road from Essex ports on vehicles that could support the extra wide loads,” HS2 reported.
“The HS2 team at West Ruislip have been preparing the site for over two years to ensure it is ready to launch the first two London TBMs in 2022. This will be an exciting step as we begin our four-year program of tunneling under London, showcasing the best of British engineering, and building Britain’s newest low carbon transport network.”
The two machines have been designed specifically to bore predominantly through Lambeth group (a set of geological rock strata), chalk and London clay, and are automated to install 4,220 tunnel segment rings each, to create each 8 km (5 mile) tunnel.
Around 15 people at a time will operate on each TBM working in shifts, keeping the machines working around the clock for two years, only stopping at Christmas and Easter. A team of approximately 40 people are working to assemble the TBMs, preparing for the launch in 2022.
“Delivering these huge TBMs to West Ruislip was an enormous logistical challenge involving 260 deliveries, including 110 abnormal loads,” said James Richardson, Managing Director of Skanska Costain STRABAG joint venture. “Our team worked tirelessly to deliver these items efficiently, whilst minimizing disruption to our neighbors. All eyes will be on West Ruislip in 2022 as we start to build the London tunnels, reaching depths of 30 m below ground.”
As the date for tunneling to begin draws closer, HS2 will be seeking to name each TBM and has already begun that process, working with local schools in Hillingdon where the TBMs will be launched. In early 2022, a shortlisted set of names will be put to a public vote, to help chose the names for HS2’s fourth and fifth TBM, after Florence, Cecilia and Dorothy who have already started their journeys underground.