Chiltern tunnel TBMs dismantled - The Dismantling of the two Herrenknecht TBMs - 170m long and weighed 2,000 t - that built HS2 (High Speed Two) Ltd’s Chiltern Tunnel have now been completed. TBM Florence broke through on HS2 (High Speed Two) Ltd’s longest tunnel on February 27, followed by TBM Cecilia on March 21.
Mammoet, who supported Align JV with the assembly of the two TBMs at the south portal, also dismantled them at the north portal after they each completed their 16.1km journey.
There were different limitations at the two sites. A 600t crawler crane was needed at the construction stage. A 400t capacity crawler crane was used to remove the biggest components from the TBMs to perform the dismantling. To remove the cutterhead, an LR1300SX crawler crane was also used to perform a tandem lift. The components were lowered onto Mammoet self-propelled modular transporters (SPMTs) before being taken to one of two laydown areas.
Bromford tunnel portal at Washwood Heath Completed
Work to build the 5.6 km (3.5 mile) Bromford tunnel bringing high speed trains into Birmingham has taken a leap forward as excavation of the 22 m deep west portal is completed. The portal at Washwood Heath has been finished in readiness for the two 1,600 t TBMs building the twin-bore tunnel to complete their journeys from Water Orton in North Warwickshire. The huge earthworks operation has taken HS2’s construction partner Balfour Beatty VINCI (BBV) nine months to complete.
The Washwood Heath portal is the deepest of the four tunnel portals on the Midlands section of the HS2 route. A two-year programme of ground reinforcement works, delivered by the Bachy Soletanche and Balfour Beatty Ground Engineering joint venture (known as SB3), began in November 2021 to prepare for the portal’s excavation.
The portal is at the start of a 750-m long cut & cover structure, which is currently being excavated and built by SB3. This is where HS2 trains will emerge from the tunnel and travel below ground level, before rising up onto a series of viaducts into Birmingham’s Curzon Street Station.
Mary Ann, the first TBM to launch from Water Orton in 2023, is expected to break through the portal wall at Washwood Heath by the end of 2024, with the second TBM Elizabeth set to finish her drive by Autumn 2025.
Next to the tunnel portal, HS2’s Depot and Network Integrated Control Centre will also be built – acting as the nerve centre of the high-speed rail network. From this site, trains will be serviced and stored and the real time operation of the railway will be controlled.
The Bromford Tunnel portal at Washwood Heath will act as the gateway that will take HS2 trains in and out of Birmingham city centre. At a depth of 22 m, completing this huge excavation operation is a significant moment for the project, and for the region.
Half of HS2 tunnels completed
HS2 has completed 26.7km (29 miles) of the new railway’s bored tunnels between Birmingham and London, HS2 has now excavated 53% of the Britain’s new high-speed line. HS2 has now completed excavation of two of its five twin-bore tunnels, with a further two well underway.
In total, high-speed trains will travel through 44 km (27.4 miles) of twin-bore tunnels – or almost a fifth of the 225 km (140-mile) route. This means that HS2’s fleet of TBMs are excavating and building a total of 88.2 km (54.8 miles) of tunnel.
The TBMs excavate the tunnels, lining them with pre-cast concrete tunnel segments, grouting them into place and moving forward at an average speed of between 12 and 16 m per day.
Once the drives are finished, HS2 moves to the next stage of the tunnelling project when other vital features such as the cross-passages, vent shafts and portals will be completed. This comes before the internal fit-out of railway systems including power, track and signalling which allows high-speed trains to operate.
In March 2023, TBM Dorothy completed its second drive of the 1.6 km (one-mile) long Itchington Wood Tunnel in Warwickshire – the first tunnel to be completed on the project.
Earlier this year, Florence and Cecilia completed both drives of the 16 km (10-mile) Chiltern tunnel – the longest tunnel on the route – with the second breakthrough witnessed in March.
In London, four TBMs are digging the 13.5 km (8.4-mile) Northolt Tunnel. Sushila and Caroline have excavated around 4.8 km (three miles) of their 8 km (five-mile) route, travelling from West Ruislip on the outskirts of the capital to Green Park Way in Greenford, north-west London. Two more are building a 5.5 km (3.4-mile) section of this tunnel in the opposite direction from Victoria Road in Ealing to Green Park Way. Emily has completed 0.3 km (0.2 miles) and Anne has just set off.
In the Midlands, Mary Ann is 2.1 km (1.3 miles) into the 5.6 km (3.5-mile) drive of the first bore of the Bromford Tunnel between Water Orton in North Warwickshire and Washwood Heath in Birmingham. Elizabeth has just started to build the second bore.
Significant preparatory works have already been completed ahead of the formal start of the 7.2 km (4.5 mile) Euston tunnel between Old Oak Common and Euston stations in London. The two TBMs are currently being manufactured and tested. The government is now exploring different funding mechanisms for delivery of the tunnel.
For further information please click here and uk/65 for the tunnelbuilder archive. Visit https://www.hs2.org.uk/. 23/24.
