By Lynda Myer
In order to that the two TBMs which are building the twin-bore tunnel complete their journeys from Water Orton in North Warwickshire, the Bromford Tunnel portal at Washwood Heath is now ready.
The time duration the earthworks operation of a team of 130 people from HS2’s construction partner Balfour Beatty Vinci (BBV) was nine months.
As the deepest of four tunnel portals on the Midlands section of the HS2 route, the Washwood Heath portal is a two-year program of ground reinforcement works, that delivered by the Bachy Soletanche and Balfour Beatty Ground Engineering joint venture (SB3) and had been commenced in November 2021 to prepare for the portal’s excavation.
The responsibility of digging and building the portal, which is at the start of a 750m-long cut and cover structure, is up to SB3. This is where HS2 trains are due to be emerge from the tunnel and travel beneath ground level, before rising onto a series of viaducts into Birmingham’s Curzon Street Station.
The estimated date for break through of Mary Ann, that is the first TBM to commission from Water Orton in 2023,at the portal wall at Washwood Heath is the end of current year, whereas TBM Elizabeth is set to finish her drive by autumn next year.
Groundwork specialists from Coventry-based Duo Group supported BBV with the complex excavation program to extract 53,400m3 of earth. The spoil has been transported on specially built haul roads to support construction of the Delta Junction – a triangular section of 13 viaducts in North Warwickshire.
As one of HS2’s largest construction sites, Washwood Heath is at 65ha.Providing the nerve center for the high-speed rail network, HS2’s Depot and Network Integrated Control Centre will also be built next to the tunnel portal. Here, trains are going to be serviced and stored and the real-time operation of the railway will be controlled.
According to Balfour Beatty Vinci project manager Tim Cook: “Completing the 22m-deep Bromford Tunnel portal was a significant moment for the project. The team is now focused on the next challenge on this vast site – a 750m-long cut and cover structure next to the portal, where HS2 trains will emerge from the tunnel and travel below ground level, before heading into Birmingham.”
The quantity of dug erea on the wider 65ha site is over than one million m3 and they reused to level the ground, paving the way for detailed design and construction of the new maintenance depot and control center to start next year.
By recycling and reusing material on the site, BBV has eliminated the need to import aggregate, a strategy which has avoided over 50,000 lorry movements on local roads.
BBV has also diverted Wash Brook, which ran south through the site. The brook, which connects to the River Tame, is one of the environmental design features planned for the site.
