The Costain/Skanska JV has completed construction of Crossrail’s Royal Oak portal almost one month ahead of schedule. Work is now underway to prepare the site for EPBM tunnelling to start next year. The portal will be the entry point for the two EPBMs that will construct the C300 western running tunnels.
Ailie MacAdam, Crossrail Central Section Delivery Director said: “Crossrail has now reached its first tunnelling milestone with the completion of Royal Oak Portal. Work is now underway to prepare for the arrival of the tunnel boring machines ahead of tunnelling commencing in spring 2012.”
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Construction of Royal Oak Portal got underway in January 2010. The portal has been built within a narrow corridor at Royal Oak, bordered by the A40 Westway to the north and the Hammersmith & City line and Network Rail lines to the south.
The works comprise a massive ramp structure that will take the Crossrail tracks from ground-level down into the underground tunnels. A total of 25,000m3 of ground was excavated to construct the tunnel portal with the excavated material re-used at construction sites in London.
At the deepest end of the ramp, a concrete headwall was constructed with a pair of 7.24m diameter tunnel ‘eyes’ created for the installation of steel rings. The tunnel ‘eyes’ mark the exact location of where the TBMs will commence tunnelling at Royal Oak.
The Paddington New Yard site, containing both the Royal Oak portal and Westbourne Park worksites, has now been handed over to the contractor undertaking construction of the Crossrail tunnels between Royal Oak and Farringdon. The contractor has begun to mobilise on-site ahead of tunnelling starting next spring and will also undertake the assembly of the tunnel boring machines at Westbourne Park.
A total of five tunnel portals will be constructed for Crossrail at Royal Oak to the west of Paddington, Pudding Mill Lane near Stratford, Victoria Dock and North Woolwich in the Royal Docks and Plumstead near Woolwich.
Main construction at Pudding Mill Lane Portal is now underway with enabling works progressing at North Woolwich and Plumstead portal sites. Construction of Victoria Dock Portal will get underway in autumn 2012.
Royal Oak portal was designed by Capita Symonds. Enabling works for the portal got underway in January 2010 with main construction commencing in April 2010.