Report - - Connaught tunnels, silvertown, London. March '11 | Underground Sites | 28DaysLater.co.uk

Report - Connaught tunnels, silvertown, London. March '11


Bespectacled & irrelevant
Regular User
Visited with OliverGT

This is from ages ago! But most of the pictures have been sitting on a hard drive at my parents house, Since I'm having a catchup day I thought I might as well post them.

After an early start at Millennium Mills this was a nice little visit to finish the day off. We noticed a lot of recent looking equipment in the tunnels, including gennys, fans, wired in lights with circuit breaker boards and even a health and safety station. I don't know what's happened since, but it looked as if work was about to start in earnest.

Text from Crosrail- http://www.crossrail.co.uk/route/stations/connaught-tunnel

The history of the Connaught Tunnel dates back to 1878. It allowed the railway to be diverted under the Connaught Passage, a water link which connected the Victoria and Albert Docks.

The Connaught Tunnel is around 550 metres long and runs between Royal Victoria Dock and Royal Albert Dock close to London City Airport. We will be enlarging the existing tunnel so that it can accommodate Crossrail trains and overhead line equipment

Sections of the existing tunnel are in a poor structural condition. Around 100 metres of tunnel wall will be removed and replaced with a new tunnel lining. The existing brick arches, part of the tunnel approaches, will be retained and repaired.

The central section of the Connaught Tunnel became weaker after the Royal Victoria Dock was deepened in 1935 to allow larger ships to enter the dock. This resulted in the roof of the Connaught Tunnel below the dock becoming exposed. As part of work to deepen the Royal Victoria Dock, the central section of the Connaught Tunnel was narrowed with brickwork removed and cast iron tunnel segments installed.

One of the first pieces of work required to be carried out is the reinforcement of the central section of the Connaught Tunnel. This section lies at the bottom of the Royal Victoria Dock at the border with the Royal Albert Dock.

A large concrete base will be installed on the dock floor to ensure the safety and stability of the Connaught Tunnel. The contractor will dredge a wide passageway in between the Royal Albert Dock and Royal Victoria Dock and install a 1m thick, reinforced concrete protection slab, measuring 1000m3 on the bed of the passageway. This is located just west of the Connaught Road Bridge. The slab will be placed using marine pontoons and with the help of specialist divers.

Following installation of the dock protection slab, the cast iron linings in the Connaught Tunnel will be removed in stages.

During this operation, the remainder of the brick-lined tunnel with be grouted and filled with a low strength foam concrete to ensure the integrity of the existing tunnel.

These tunnels will then be enlarged by boring through the foam creating binocular tunnels large enough to allow Crossrail trains to pass. Precast concrete tunnel segments will be installed in this section of the tunnel.











Cheers :thumb