The first permanent works began at the site in February 2021 when the team poured a 160m3 concrete collar around the ancillary shaft.
They then built the first 11m of the 25m internal diameter shaft using precast concrete segments, produced by FP McCann Ltd, before completing the final 19metre depth using the sprayed concrete lining technique.
The team of around 30 engineers and operatives have since completed the shaft with a 3.3m thick base slab constructed in three different pours.
The main pour of around 1,000 m3 of concrete took place at the end of 2021, and the second and third completed by the end of January 2022 adding another 740 m3 of concrete.
The site will provide critical infrastructure for the operation of HS2. As well as the 25m internal diameter shaft, which will provide ventilation and emergency access to the Northolt Tunnels, SCS JV is building a crossover box on the site that will let trains switch tracks on the way in and out of Old Oak Common station.
HS2’s Project Client, Malcolm Codling said: “The team at Victoria Road have made huge strides, completing the base slab of the ancillary shaft, and preparing the site for the launch of two tunnel boring machines. As we move into the next phase of work. It won’t be long until we begin to see where the railway will run through the site, taking it from our detailed construction plans to reality.”
Skanska Costain STRABAG Joint Venture’s Managing Director, James Richardson added: “We’re constructing eight ventilation shafts along our 13 miles of twin bore tunnels in London and this vent shaft is the first to advance to this stage.
“Work is progressing well at all our other shaft sites so that they are ready for the tunnel boring machines to travel through them as our huge tunnelling programme progresses over the next three years.”
The site at Victoria Road also has a crucial role to play in construction.
SCS JV will use it to assemble and launch two tunnel boring machines (TBMs) that will dig the 3.4-mile eastern section of the Northolt tunnels. The TBMs are due to arrive in early 2023 and will begin the 12 month programme of tunnelling later that year.
The site will also be connected to the Logistics Hub located at the Willesden Euroterminal by a conveyor system that will remove spoil excavated for the tunnels.
The conveyor system, which also connects the Logistics Hub to Old Oak Common station site, will become operational later this year and will contribute to reducing lorry movements for HS2, removing around 1million lorries from the road.
