Page 14 - Contractors World -UK & Ireland Vol 2 No 4 (May 2012)

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Page 14
Contractors World - UK & Ireland Vol 2 No 4
Crossrail’s first tunnel boring
machine breaks ground
at Royal Oak
Crossrail’s first Herrenknech giant tunnel boring machine (TBM), Phyllis, has broken ground at Royal Oak to construct the
first section of tunnel between Royal Oak and Farringdon.
Keith Sibley, Crossrail Area Director West said, “Tunnelling for Crossrail has now commenced. Phyllis is now beginning
to slowly disappear below ground and will steadily ramp up to the planned average tunnelling rate of around 100 metres
a week.”
Following the official unveiling of 1,000 tonne Phyllis, Crossrail’s first tunnel boring machine (TBM) travelled 400
metres to Royal Oak Portal including under Hampden Street footbridge which was jacked up to allow the 7.1 metre
diameter machine underneath.
The arrival of the TBM at the portal in mid-March allowed for remaining major works to get underway to support
tunnelling.
A major piece of work has been the
construction of the launch structure which
allows the TBM to propel itself forward. The
total force required for the TBM to move
forward is equivalent to the force needed
to lift over 2,900 London taxis. A steel seal
was fitted around the portal entrance to
support the ground during the early stages of
tunnelling.
Work has also been underway to install
the major conveyor system behind the TBM
to remove more than one million tonnes of
excavated material from the cutter head to
the portal entrance. A total of 24 kilometres
of conveyer belt will be used to construct the
western tunnels.
Rail sidings have been constructed to
allow freight trains to access Westbourne
Park to transport the excavated material to
Northfleet from where it will be shipped to
Wallasea Island to create a nature reserve.