Incrementally launched Thurrock Viaduct pushed under the M25 motorway by huge hydraulic jacks on the Channel Tunnel Rail Link
One of the most imaginative engineering solutions on the Channel Tunnel Rail Link was the Thurrock Viaduct. This is a 23-span pre-stressed box girder viaduct constructed by using an incremental launch system and, at 1,025m long, is the largest push-launch structure in the UK. Each of the 45 metre segments weighing 300 tonnes was precast prior to launch on site and attached to the previous construction. The ever-lengthening structure was pushed out by huge hydraulic jacks until the whole 1,025 metre long viaduct was completed. The viaduct steadily crossed the Essex marshes and, as it progressed, the leading edge or `nose' crossed over the London, Tilbury and Southend electrified railway lines, the Essex viaduct (at the exit of the Dartford tunnels) and passed under the Queen Elizabeth II bridge which carries the M25 motorway. The £ billion Channel Tunnel Rail Link (now High Speed One) was built between 1998-2007 and partly funded by the European Union, it forms a section of the Trans European Rail Network. It is basically a French-style high-speed rail line linking London with the Channel Tunnel, the Eurostar trains were developed on proven technology from the French TGV high-speed system. Stations on the CTRL are the existing Ashford International and new stations at Ebbsfleet and Stratford. The line ends at the rebuilt St. Pancras. Fourteen new tunnels were constructed, the longest being the London Tunnel which is long from Ripple Lane to Stratford, after which the line briefly comes to the surface at Stratford Station. Five huge shafts of diameter ventilate the twin bore, single-track tunnels and provide emergency access and evacuation points. The line passes in tunnel under the River Thames and crosses the M25 at Thurrock. For the Thames crossing (a 3km twin-bore tunnel), the line drops 1 in 40 down under the river and then climbs 1 in 40 up, curving at the same time.
Size: 4064px × 2704px
Location: Thurrock, Kent, UK.
Photo credit: © qaphotos.com / Alamy / Afripics
License: Licensed
Model Released: No
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