The tunnel dull device (TBM) Emily has finished her 3.4-mile force, turning into the 3rd of 4 machines to finish its paintings at the 8.4-mile lengthy Northolt Tunnel for the HS2 rail mission.
Northolt Tunnel, between the outer fringe of the capital and the brand new Outdated Oak Not unusual station in west London, is the second one longest tunnel at the HS2 line, after the 10-mile Chiltern tunnel.
Primary contractor in this phase is Skanska Costain Strabag JV (SCS JV).
The Northolt Tunnel is being constructed the usage of 4 separate TBMs– two development the western phase from West Ruislip and two development the jap phase from Victoria Street in North Acton. TBM Emily broke thru Inexperienced Park Method in Greenford this week.
She was once introduced in February 2024 and has finished one bore of the jap phase of the tunnel – taking out 775,000 tonnes of London Clay and putting in 17,514 tunnel segments.
The machines all end at Inexperienced Park Method, the place they’re then lifted out from the shaft. The general device is predicted to finish its force later this yr. Because of prime water force within the floor on the website at Inexperienced Park Method, the TBMs are completing their drives in a reception can within the shaft. The reception can way permits the TBM to handle force whilst sealant can also be carried out from the tunnel lining, combating water ingress. It’s then depressurised prior to it’s opened and the TBM is lifted out.
Malcolm Codling, mission shopper director for HS2 Ltd, mentioned: “HS2’s tunnelling drives in London for the Northolt Tunnel are nearing crowning glory and this can be a actual success for our group to finish this 3.4-mile phase at the tunnel safely and with such potency.
“There may be nonetheless a lot more to do within the tunnel to get it HS2 able and we will be able to be specializing in productiveness to proceed with our paintings safely to get the HS2 path in London able for monitor to be laid, and techniques put in.”
Manufactured by means of Herrenknecht in Germany, TBM Emily weighs 1,700 tonnes and has a 9.11-metre diameter cutterhead. She is an earth force steadiness device, designed in particular for the comfortable London Clay.
At top manufacturing, the TBM complicated at round 38 metres in line with day. Tunnel lining segments had been forged in Hartlepool, 250 miles away, by means of Strabag.
The London Clay extracted has been taken clear of Victoria Street Crossover Field, close to Outdated Oak Not unusual station, by means of conveyor to the London Logistics Hub at Willesden Euro Terminal. From there, it was once transported by means of rail and reused at websites in Cambridgeshire, Kent and Warwickshire.
Two different TBMs, Sushila and Caroline, bored the western phase of the tunnel from West Ruislip, breaking thru in December 2024 and April 2025, respectively.
TBM Emily broke thru on Friday 6th June, whilst the fourth Northolt TBM, Anne, is because of whole its force in the summertime.
Dave Hannon, SCS JV mission director, tunnels & routeway, mentioned: “The coming of TBM Emily at Inexperienced Park Method marks an important milestone within the programme. We at the moment are drawing near crowning glory of the Northolt Tunnel – a thrilling success and a testomony to the collaboration, willpower, and technical functions of our groups.
“With our persevered center of attention we’re urgent forward at tempo to finish the rest works, together with pass passages, tunnel walkways, air flow shafts, headhouses, and portals, as we ship on a part of the HS2 mission.”
As soon as the entire construction of the tunnel is whole, the SCS JV group will end development 34 pass passages between the 2 tunnel bores. The air flow and emergency get right of entry to shafts have additionally but to be finished.
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