HS2’s Chiltons Tunnel Sealing Rings Placed by Ainscough Crane Hire
Ainscough Crane Hire has worked with client Sian Formwork to help complete one of the key milestones in the early stages of HS2 on behalf of Align, a joint venture of the three leading construction companies delivering the Central 1 portion of HS2, Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick.
As part of the first phase of HS2, two giant 2,000t, 558ft long tunnel boring machines (TBMs) will soon begin drilling through 16 km of chalk and flint to complete the Chilterns Tunnel, which will begin to the west of London just inside the M25 and end near South Heath in Buckinghamshire.
The TBMs will be excavating for three years and will go as deep as 90m below ground level. Each completed tunnel will be 9.1m in diameter and will be lined with concrete segments as the TBM advances.
The TBMs have ‘cutterheads’ at the front which are able to rotate up to 3.2 times a minute as they bore through the earth, excavating material which is then removed from the TBM by a hydraulic slurry circuit. Each machine will remove roughly 1.3 million cubic metres of earth and rock.
The digging will help form phase one of the high-speed line, which will connect London and the West Midlands, with phase two extending into the East Midlands and North.
At 10 miles, the Chiltern Tunnel is the longest on the project.
Ainscough worked with Sian Formwork to install two tunnel sealing rings on the portal face. The two rings weigh 22t and have diameter of 10m, installed at a working radius of 28m. In order to complete the work, a 100t crane from Ainscough’s West London depot and a 450t crane from Ainscough’s Heavy Cranes team were utilised to allow the rings to be “top and tailed”.
The 450t crane was operated by Kevin Smith, with the lift planned by Patrick Denby.
Phil Davies, area sales manager at Ainscough Crane Hire, said: “It was a proud moment for Ainscough to work with Sian Formwork and the Align Joint Venture on a key milestone for HS2. It was brilliant to be part of a key stage of an infrastructure project which is awe-inspiring. We look forward to completing further work on HS2 this year.”
Kevin Knapp, engineering manager, Sian Formwork, said: ‘’Working alongside Ainscough Crane Hire, we have successfully delivered the reinforced concrete works to the South Portal Tunnel Approach to an extremely tight programme, despite the challenges that COVID 19 has added.
“Once again, Ainscough has worked hand in hand with our project engineering teams to deliver the complex lifting required.
“All involved should be very proud of their collaborative achievements and we look forward to delivering more successful schemes alongside Ainscough Crane Hire.”
The two TBMs have been named Cecilia and Florence, after Buckinghamshire-born astronomer Cecilia Payne-Gaposchkin and Florence Nightingale.
Source Ainscough Crane Hire