HS2 Chiltern tunnel launchpad ready for giant TBMs

Grant Prior 4 years ago
Share

Preparation for the arrival of HS2’s first giant tunnelling machines is now complete with construction of the 17m high headwall and ground reinforcement at what will become the south portal of the 10-mile long Chiltern tunnel.

Main works contractor Align JV – a joint venture formed of Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick – has spent seven months excavating more than 160,000 m3 of material in order to create a level surface from which the two enormous machines will launch early next year.

Weighing in at 2,000 tonne and stretching for 170m – the two tunnel boring machines (TBMs) are being built by German tunnelling specialists Herrenknecht – and due to arrive at the site, near to the M25, later in the year.

Alongside the excavation, a specialist team of subcontractors including Roadbridge and KV JV – formed from Keller Group plc and VSL International – also constructed a 17m high headwall through which the TBMs will break to begin their three-year long tunnel drive.

In order to reinforce the ground behind the headwall, more than 636 soil nails – some up to 20m long – were driven into the wall and connected to the concrete lining.

The nails, consisting of steel or glass fibre reinforced polymer tendons, were inserted using a specialised drilling rig in a delicate operation which can take up two hours.

This reinforcement is required to hold the ground and the surface of the wall in place as the TBMs begin to break through.

Welcoming the milestone, Mark Clapp, HS2 Ltd’s C1 Senior Project Manager said: “The completion of the headwall and ground reinforcement is a major step towards the start of tunnelling.

“Safety is of course our top priority. The new covid-19 processes and procedures put in place by Align ensured that we were able to keep to schedule while keeping everyone safe – and I’d like to thank the whole team for pulling together during what has been a difficult few months for the whole construction industry.”

Daniel Altier, the Align Project Director added: “The completion of the soil nailing is a very visual example of how we are preparing our South Portal site for the arrival of the TBMs later this year. It is now clear for all to see where the TBMs will start their journey.

“This has been a great team effort by all concerned, considering the challenges caused by Covid-19, including HS2, Align and our colleagues at Roadbridge and the KVJV.”

Align is delivering the C1 portion of HS2 phase 1 which includes the 10 mile long twin bore Chiltern tunnel and the 3.4km Colne Valley Viaduct. The work is being led by an integrated project team based at the site just inside the M25.

Work on site was paused for four days at the start of the coronavirus lockdown in order to deep clean the work site and put in place new hygiene and social distancing procedures in line with government advice and industry best practice.

Once work is complete, the whole construction site will be landscaped with material excavated from the tunnels and trees planted in order to blend it in with the surrounding countryside.

Latest news

Historic property magazine to close

Estates Gazette has been in business since 1858
8 hours ago

M&S Marble Arch rebuild approved after three-year planning fight

Plans were delayed when Michael Gove backed carbon campaigners
1 day ago

£191m revamp funding approved for London Barbican Centre

Construction to start in 2027 on five-year programme
1 day ago

RED Construction tops £100m turnover

Builder maintains profit margin at 1.7% as business nearly doubles in size
16 hours ago

Timber designs shortlisted for roads ‘footbridge of the future’

Three of five designs for National Highways propose timber structures over busy highways
16 hours ago

PM pledges to fast-track 150 infrastructure schemes

Fresh promise to speed up planning decisions on infrastructure and house building
1 day ago

Amey FM firm fined after legionella kills prisoner

Court fines company £600,000 for prison upkeep failures
16 hours ago

Buyers report boom in commercial work

Construction bucks slowdown in general economy
2 days ago

Plans in for £250m Stockport 8 housing-led scheme

Work to start on phase 1 by the end of next year
2 days ago

Galliford Try tops monthly contracts league

Contract awards slow down in November
2 days ago

Erith explosives set demolition record at Sizewell

Watch blast at former nuclear turbine hall: Video
2 days ago

Vistry to build 950 homes next to Olympic Park

Developer signed for £600m Pudding Mill Lane scheme in East London
2 days ago

Inflatable formwork used for 45m tall cement silo

Ground-breaking dome silo inflated at Tilbury Docks
2 days ago

Briggs & Forrester sells maintenance arm

100 engineers to move over to new owner
2 days ago

£2bn Edinburgh ‘West Town’ scheme approved

7,000 homes to be built at 205-acre site
2 days ago

Rayner approves Lancashire super prison

Communities secretary overrules planning inspector for 1,700 inmate prison.
3 days ago

Wates boss returns after collapse of his own contractor

Paul Nicholls was head of the failed Real construction group
4 days ago

Trio secure Birmingham deal to retrofit 3,000 homes a year

Specialist contractors to install insulation, efficient heating and solar panels
3 days ago

Costain confirms £400m HS2 tunnels win

Work to start early next year on tunnel and lineside mechanical and electrical systems
3 days ago

First nuclear reactor installed at Hinkley: Video

Watch precision operation at Somerset site
3 days ago

Winner named for Harbourside revamp

Local Irvine contractor to start transformation of beach front
3 days ago

New Fair Payment Code goes live today

Latest bid to get subcontractors and suppliers paid within 30 days
4 days ago

Lincolnshire concrete supplier files administration notice

Ever Readymix Concrete & Screed operates three depots and a fleet of 20 trucks
4 days ago

Graham lands first deal on Liverpool’s largest brownfield site

Contractor bags infrastructure package on 10.5 hectare site
4 days ago

Bouygues UK boss to step down

Fabienne Viala to leave after eight years at the helm
4 days ago

Galliford Try scoops £87m brace of London jobs

Firm will redevelop a prominent corner building on Sloane Street in Chelsea
4 days ago

New HS2 boss Mark Wild starts amid prep for final TBM drives

Former Crossrail CEO starts with a sharp focus on controlling costs
4 days ago

Ten consultants land Thames Water major upgrade places

Firms will share £400m of fee work over next five years
4 days ago

Rayner ultimatum to fix all unsafe tall buildings by 2029

Recladding work must start on all 18m+ resi buildings by 2027
4 days ago

ISG administrator finds just £35m to pay down £1.1bn debt

Failed firm was set to report £148m blackhole from legacy jobs
5 days ago

Contractor services