Four million tons of clay moved in HS2 excavation

"Four giant tunnelling machines working below west London have completed the excavation of the 8.4-mile (13.5km) Northolt tunnel between West Ruislip and a new station at Old Oak Common as part of the HS2 project. The Tunnel Boring Machines (TBM) excavated more than four million tonnes of London Clay and installed almost 100,000 concrete segments to form the tunnel walls, according to HS2."

"The first part of TBM, "Anne", saw the light of day for the first time in 16 months as it was lifted out of a shaft at Green Park Way in Greenford, west London, on Sunday. HS2 Anne is named after Lady Anne Byron, an educational reformer and philanthropist who established the Ealing Grove School in 1834, England's first co-operative school. The machine weighs 1,700 tonnes and stretches for around 490ft (150m), including the 30ft (9.11m) diameter cutter head."

Four giant TBMs have completed excavation of the 8.4-mile Northolt tunnel between West Ruislip and Old Oak Common beneath west London. The machines removed more than four million tonnes of London Clay and installed almost 100,000 concrete segments to form the tunnel lining. Engineers have begun lifting the last TBMs to the surface, with part of TBM "Anne" emerging after 16 months. "Anne" is named for Lady Anne Byron, weighs 1,700 tonnes, and extends about 490ft including a 30ft diameter cutter head. The cutters advanced about 50ft per day with 17-person crews operating 24/7. Excavated material was sent to designated sustainable disposal sites and transported by rail.

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