Long Itchington Wood Tunnel
The Long Itchington Wood Tunnel is a 1 mile (1.6km), twin bore tunnel on the new high speed railway in Warwickshire.
The tunnel will run under Long Itchington Wood in Warwickshire – an ancient woodland – and is an important part of HS2’s environmental strategy to protect nature.
One tunnel boring machine, TBM Dorothy, is being used to create the tunnel and is the first TBM on the Midlands section of HS2.
Tunnel construction
The giant 125m long TBM, which started its journey at the tunnel’s North Portal in December 2021, broke through the wall of the reception box at the South Portal site for the first time in July 2022. Relaunched in November 2022, it’s only took four months for the 2,000 tonne TBM to complete its one-mile second bore, making this the first complete twin-bore tunnel on the HS2 project.
After HS2’s first tunnel breakthrough by TBM ‘Dorothy’ at the south portal site in July 2022, the gantries of the tunnel boring machine, which weigh over 1,000 tonnes, were brought back through the tunnel and reassembled at the north portal. The huge cutterhead, weighing 160 tonnes and with a 10 metre diameter, was moved by road during an intricate night-time operation in September. The TBM’s 130 tonne tail skin and eight other large pieces from the TBM’s front shield and middle shield, were also transported by specialist equipment.
The tunnelling team worked around the clock in shifts to operate the TBM, which put 791 concrete rings in place, with each ring made from eight two-metre-wide segments that each weigh up to 8 tonnes.
Excavation of the twin bore tunnel produced around 500,000 tonnes of mudstone, which is being processed at an on-site slurry treatment plant. From there, it is separated out before being transported by a 254 metre conveyer to be used to build embankments along the route of the railway, removing the equivalent of around 30,000 HGVs from local roads, reducing impacts on the local community and cutting carbon.
Work will now begin to dismantle the shield from the TBM, while the rest of the machine will be pulled back to the start of the tunnel and disassembled, ready for transportation to East Birmingham. There, the TBM will be fitted with a new shield so that it can begin a 3.5 mile (5.6km) tunnel bore in early 2024, between Water Orton in Warwickshire and Washwood Heath in Birmingham.
This was the sixth tunnel launch on the project, but the first time a TBM has been reassembled and reused.
Long Itchington Wood Tunnel – key construction milestones
Protecting Long Itchington’s ancient woodland
Long Itchington Wood and neighbouring Ufton Wood are a single block of ancient woodland dating from at least 1600AD. They are a Site of Special Scientific Interest (SSSI) with very complex ecosystems that have taken hundreds of years to establish. This is only one part of our environment programme. In the Midlands we’ve already planted over 340,000 trees and created 62 new habitat sites for wildlife which are already thriving.