| NEWS
Final TBM launch for HS2 Northolt Tunnel
TBM finish on Virginia project US – Tunneling for RiverRenew, a wastewater project in Alexandria, Virginia, has been completed. TBM ‘Hazel’, which was launched in
November 2022, recently broke through after boring a tunnel under Old Town Alexandria and the Potomac River. The 30.5m-diameter Herrenknecht TBM
broke through in a 30.5m-deep shaft, which in future will collect combined sewage overflows from an existing outfall and direct the flows through the new tunnel to Alexandria’s wastewater treatment provider, AlexRenew. The wastewater will be treated and returned to the Potomac River. Completing excavation of the new
Waterfront Tunnel marks the integration of AlexRenew’s wastewater plant with all four of the city’s combined sewer outfalls (CSOs) that date back to the 1860s. The remaining works include the
Above: Final TBM launched for HS2 Northolt Tunnel PHOTO CREDIT: HS2
UK – The fourth, and final, TBM for HS2’s Northolt Tunnel beneath London, has been launched. TBM ‘Anne’ will bore 3.4 miles
(5.5km) from Victoria Road in Ealing, near HS2’s Old Oak Common station, to Greenpark Way in Greenford, alongside TBM ‘Emily’ which launched in February. The 8.4 miles-long (13.5km) Northolt Tunnel will run from Victoria Road in Ealing to West Ruislip in Hillingdon. The other 5 miles (8km) of
twin-bored tunnels has been under construction since 2022, with TBMs ‘Sushila’ and ‘Caroline’ both over halfway through their journey between West Ruislip, on the outskirts of London, and Greenpark Way. The four TBMs on Northolt Tunnel
are to complete their journeys in 2025.
TBM ‘Anne’ – an EPBM
manufactured by Herrenknecht – is 186yd-long (170m) and has a 29.9ft-diameter (9.11m) cutterhead. It was lowered in parts into the crossover box at the end of 2023. It will install concrete rings with
an external diameter of 28.8ft- diameter (8.78m), an internal diameter of 26.6ft-diameter (8.10m), each made up of seven segments. Each segment weighs approximately 7 tons and are
being manufactured in Hartlepool by Strabag from where they are transported to London by train. HS2’s London tunnels contractor,
Skanska Costain Strabag (SCS) joint venture, has delivered an extensive program of work for the TBM to launch at the Victoria Road Crossover Box, excavating the caterpillar-shaped box where eventually the trains will cross tracks on their way in and out of Old Oak Common station. TBM Anne is the eighth TBM to
be launched to date across the HS2 project. In all, almost half of the 65 miles (105km) worth of twin-bored tunnels has now been excavated. The London Clay excavated by TBM
‘Anne’ will be taken away from the Victoria Road Crossover Box site via a conveyor, removing the need for local lorry movements. From there, it is transported to HS2’s London Logistics Hub at the Willesden Euroterminal site where it is sorted, before being taken by train for reuse across the UK. In total, 10 machines are building
the HS2 tunnels. Two remaining TBMs, which will eventually be used to dig the final tunnel between Old Oak Common and Euston, in central London, once the government gives approval, are still being built. They are to be delivered this year.
completion of a smaller sewer line along Hooffs Run, fitting out the drop shafts, and constructing a 12-storey underground pumping station at AlexRenew. Work is expected to continue throughout 2025.
Start on Pape Tunnel CANADA – Infrastructure Ontario and Metrolinx recently selected the Pape North Connect team to deliver the Ontario Line Pape Tunnel and Underground Stations contract in Toronto. The Pape North Connect consortium
signed a Development and Master Construction Agreement (DMCA) with Metrolinx, under a progressive design- build contract. The team includes: the construction team of Webuild Civil Work and Fomento de Construcciones y Contratas Canada Ltd; and, the design team of Arcadis Professional Services (Canada) Inc and Aecom Canada Ltd. The DMCA contract incorporates a multi-
stage design process called a development phase, according to the progressive design- build model. The development phase allows for a
collaborative approach between Metrolinx and the consortium to finalize the scope, risk allocation and pricing of various elements of the contract. This phase is expected to take 24 months, though early works can commence start. Follow the development phase, Metrolinx
has the option to sign a final target-price agreement, which would include final agreements on detailed designs and a negotiated price.
Summer 2024 | 11
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69
