2432 x 2432 px | 41,2 x 41,2 cm | 16,2 x 16,2 inches | 150dpi
Date de la prise de vue:
15 mai 2002
Lieu:
Swanscombe, Kent, UK.
Informations supplémentaires:
Cette image peut avoir des imperfections car il s’agit d’une image historique ou de reportage.
Tailskin section of 8.15m diameter slurry-type tunnel boring machine (TBM) 'Milly the Muncher Cruncher' (named by local schoolchildren) is lowered into the launch chamber at Swanscombe, Kent, to begin its 2.5km drive under the River Thames. Fully assembled, the TBM weighed 1000 tonnes and was 95m long. The ground under the river was soft water-bearing rock, gravel and chalk containing many hard flints. The soft and wet excavated material was mixed with bentonite inside the cutterhead and the resulting suspension was pumped to the surface for disposal. Slurry-type TBMs have pressurised compartments at the front end, allowing them to be used in difficult ground conditions below the water table. The operators work in normal air pressure behind the pressurised compartments, but may occasionally have to enter those compartment to renew or repair the cutters. For the Thames crossing (a 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. The £5.2 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 10.5km long from Ripple Lane to Stratford, after which the line briefly comes to the surface at Stratford Station. Five huge shafts of 17.15m diameter ventilate the twin bore, single-track tunnels and provide emergency access and evacuation points.
