The first fully finished cut-and-cover tunnel on the HS2 line has been revealed on the west side of London.
The Copthall tunnel is the first HS2 green tunnel, and is 880 metres long.
Located near West Ruislip, around 1.2 m³ of material was excavated during construction.
The only ‘single-bore’ tunnel on the HS2 line
The tunnel underwent a design change: it was originally planned as an open-cut design, but it was decided that a cut-and-cover tunnel would be the better option. This meant that the material excavated from the dig could be kept on site and would not need to be transported elsewhere, reducing the complexity of the operation and cutting roughly 100,000 truck movements.
The Copthall tunnel is the only ‘single-bore’ tunnel on the line and, as such, is massive in size, allowing trains to pass each other without issues caused by forces at 200 mph.
As a cut-and-cover tunnel, the Copthall tunnel is one of five and is the first to be completed in terms of the tunnel structure and the earth covering it, leaving only the plant life to be put in place on top to blend it into the landscape.
The other tunnels are under construction, with the structure of the Chipping Warden tunnel being finished earlier this month.
Rail minister, Lord Peter Hendy, said: “The completion of Copthall tunnel marks another significant milestone for HS2. Making use of innovative design, the tunnel reduces the impact on nearby communities by blending into its surroundings whilst keeping thousands of truck journeys off local roads by using materials close to the site.
“Our reset of HS2 is driving faster, more efficient construction on-the-ground and supporting thousands of jobs as we work to deliver the project at the lowest reasonable cost.”
Northern Powerhouse Rail warned against repeating HS2’s mistakes
Earlier this month, the Public Accounts Committee released a report warning that in its current state, the plans for Northern Powerhouse Rail are set to repeat the issues that HS2 faced, with uncertainty and questions wreathed through a plan that, despite being in progress for 12 years, is still in the early stages.
Clive Betts MP, deputy chair of the Public Accounts Committee, said: “The government’s growth strategy earlier this year signalled that there is still an appetite to finally deliver the transport infrastructure the North so badly needs. But the spectre of HS2 hangs over Northern Powerhouse Rail.
“Our Committee has heard troubling echoes of the same mistakes in loose governance that HS2 made early on, and so much of the project remains almost impressionistic, twelve years on. HS2 have even been brought on board to develop NPR’s own plans. As HS2 has been a casebook example of how not to run a major project, so their involvement in NPR does not fill us with confidence.
“Both the Treasury and DfT have questions to answer about the project’s £45bn funding cap. Given the fact that this project has not been fully scoped or designed, it is hard to see how the government was able to arrive at a hard £45bn cap.
The post First HS2 green tunnel completed appeared first on Planning, Building & Construction Today.
