expert engineers, and those of our contractors, then
advise on how to best manage that settlement.”
T
o deliver the Crossrail branch to Abbey Wood, a
part of the construction work involves reusing
the disused Connaught Tunnel on the former
North London Line branch to North Woolwich. Around
550 metres long, the Connaught Tunnel is a Victorian
structure that runs between Royal Victoria Dock and Royal
Albert Dock close to London City Airport.
“Reusing the Connaught Tunnel came with its own
challenges. Probably the biggest of which was the fact
that the tunnel wasn’t big enough to accommodate
Crossrail trains and the overhead electrical equipment the
trains run on. That meant it needed to be widened and
deepened.”
“The original plans to take a TBM through that section
had to be adapted when it was discovered that the
tunnel was in a less stable condition than expected. We
had to change the type of work we were doing, put in a
cofferdam, and drain approximately 13 million litres of
water from the Docks to allow access to the tunnel from
above.”
“Despite the fact that a lot of this tunnel was
documented – we managed to get hold of the engineering
drawings – it was not until we got in and specifically
surveyed the structure that we realised what we were
dealing with. The Victorians constructed the tunnel to
withstand a great deal and the actual mortar of the brick
structure is immense and difficult to break out.”
“As with any underground construction, it is important
to know what the ground has been used for previously
and what might be leaching through as a result. Methane
and hydrogen sulphide gas, for example, can be an issue.
That part of London was also heavily targeted during
World War II, so we carried out extensive surveys to look
for unexploded devices.”
Crossrail pushes the boundaries for a construction
project from a sustainability perspective as well. The
company appreciates the disruption the project causes,
and has strong teams in place to liaise closely with the
local community.
Crossrail is particularly proud of its program to protect
vulnerable road users in London and insists that all its
vehicles must meet safety requirements, well above
the standard, to protect cyclists. No vehicle accesses a
Crossrail site unless it meets these standards. To date,
the company has trained more than 7,300 drivers and
these standards have now been adopted across London.
Crossrail has been instrumental in the creation of a workrelated safety guidance document for HGV drivers and a
number of hauliers have implemented these standards
across their entire fleet.
When asked what advice he would give others hoping
to maintain such high levels of health and safety, Hails
said, “I’ve already mentioned the importance of learning
lessons from others and the need to engage with other
projects as soon as you possibly can. Engagement with
your tier one contractors is key. You must then make sure
your contractors then engage with their supply chain
and that all employers engage with their employees. It
is also important to create a common vision.