Balfour Beatty VINCI’s development of HS2’s gateway to Birmingham takes a leap ahead as the massive 125-metre-long tunnel boring machine (TBM) digging the primary bore of the Bromford Tunnel reaches the midway level.
The 1,600 tonne TBM, named ‘Mary Ann’ – the actual title of Warwickshire-born creator George Eliot – has excavated and constructed 1.75 miles of the primary bore of the tunnel because it began digging from a big underground field in Water Orton final 12 months.
Driving round 40 metres underground in direction of Washwood Heath in Birmingham, the TBM has excavated beneath the Park Corridor Nature Reserve and River Tame and is now passing beneath Citadel Vale. It should proceed adjoining to and beneath the M6 earlier than breaking via at Washwood Heath early subsequent 12 months.
An knowledgeable tunnelling staff have been working across the clock on shifts to function the TBM, which additionally builds the tunnel because it excavates. A complete of 20,797 concrete segments will probably be put in place by the machine, making 2,971 concrete rings to type the tunnel.
The tunnel’s 47-metre-deep air flow shaft at Citadel Vale marks the midway level of the TBM. The shaft, which is eighteen.6 metres in diameter, will function cross passages which can ultimately hyperlink to the 2 tunnels both aspect to offer air flow, servicing and emergency entry. A ‘headhouse’ will probably be constructed on high of the shaft, and the entire construction will probably be full in 2027.
‘Elizabeth’, the second TBM – named after Dame Elizabeth Cadbury by native college pupils, began constructing the tunnel’s second bore in March 2024 and is because of end her journey in direction of the tip of 2025.
The 2 TBMs will take away 1.87 million tonnes of excavated materials, which is being sifted on the on-site slurry therapy plant and reused on close by websites on the Delta Junction, the place a fancy community of 13 viaducts is being constructed. HS2 has constructed devoted roads between these development websites, together with an entry off the M6/M42 hyperlink roads, to be able to take lorries off public roads.
In preparation for the arrival of the TBMs at Washwood Heath, an enormous earthworks operation has been accomplished by a staff of 130 individuals to construct the tunnel’s west portal, which at 22 metres under floor is the deepest of the 4 tunnel portals on the Midlands part of the HS2 route.
The portal is initially of a 750-metre-long reduce and canopy construction, which is at present being excavated and constructed. That is the place HS2 trains will emerge from the Bromford Tunnel and journey under floor stage, earlier than elevating up onto a sequence of viaducts via Birmingham’s industrial heartland and into Curzon Avenue Station.
Jules Arlaud, Tunnelling Director for Balfour Beatty VINCI stated: “Reaching the midway level on this complicated stretch of the HS2 route into Birmingham is a superb milestone for our 180-strong tunnelling staff.
“We’re trying forward now to delivering the ultimate levels of tunnelling and celebrating the breakthrough of each TBMs at Washwood Heath subsequent 12 months.”
Steve Powell, HS2’s Head of Supply stated: “We’re now at peak development within the West Midlands, and it’s nice to rejoice the midway level for the ‘Mary Ann’ tunnel drive into Birmingham. By the tip of subsequent 12 months, each of those tunnels will probably be constructed, marking a major step in HS2’s development within the area.
“Round 31,000 individuals are engaged on HS2, with round a 3rd of those within the West Midlands together with 615 apprentices and over 1,650 individuals who had been beforehand unemployed, offering a singular alternative for native individuals to be taught new abilities whereas delivering the UK’s largest development programme.”
Liam Byrne, Labour MP for Hodge Hill and Solihull North stated: “The extraordinary tunnelling beneath Water Orton and Birmingham is a world-class little bit of engineering which might have made Matthew Bolton and James Watt proud. What’s extra, there at the moment are extra native residents engaged on the venture than ever earlier than.
“HS2 goes to rework the economic system of Birmingham and the West Midlands and the primary trains will probably be working in only a few years’ time. What’s now wanted is identical genius that there’s on this energy of engineering to assist us work out the best way to carry down prices and drive up the financial advantages to the town and to Solihull.”
The specialist tunnelling groups are from UK agency Tunnelcraft, and Solihull-based Rorcon, with a complete of ten apprentices together with previously unemployed individuals from the native space who now have jobs on the venture.
As soon as full, HS2 providers will run between London and the West Midlands on a devoted high-speed line earlier than linking reaching locations additional north by way of the present West Coast Essential Line. It should present considerably extra environment friendly and sooner journeys, whereas relieving stress on probably the most congested southern finish of the West Coast Essential Line, permitting extra native and freight trains to function.