Spray operativa spritzbeton dal tubo flessibile ad alta pressione per stabilizzare lo scavo durante la costruzione del Regno Unito Channel Tunnel Crossover
3324 x 3324 px | 28,1 x 28,1 cm | 11,1 x 11,1 inches | 300dpi
Data acquisizione:
4 aprile 1990
Ubicazione:
40m under sea bed, 8kms from Dover, Europe.
Altre informazioni:
Questa immagine potrebbe avere delle imperfezioni perché è storica o di reportage.
Sprayed concrete (called shotcrete) is used in construction projects around the world. Quick-setting concrete is sprayed onto the bare rock surface immediately after excavation and rapidly hardens to form a preliminary support for the structure as well as protecting the tunnelling crew from rock falls until the final lining of conventional poured concrete can be installed. The shotcrete is delivered through high-pressure hoses and quickly dries to stabilise the workface. It is vital for the operatives to wear correct protective equipment during this operation because the additives in the shotcrete are highly toxic if breathed in or swallowed or if they come into contact with skin or eyes. During the construction of the Channel Tunnel under the sea, two vast Crossovers were constructed about 8 kilometres from the UK and the French coasts. These were the largest undersea caverns ever built (156m long, 18.1m wide and 10.5m high) and allow trains in the two rail tunnels to switch from track to track to facilitate maintenance. The UK Crossover was built by using the New Austrian Tunnelling Method (NATM) that was considered to be fast, flexible and cost-effective - the cavern was built in just seven months. The Channel Tunnel is no ordinary project. The four types of cross-channel service that the Tunnel offers - conventional freight and passenger trains, plus two types of road vehicle shuttle have made it into the busiest railway in the world. The fast and efficient movement of road and rail traffic into, through and out of the Eurotunnel system is integral to that success. The Channel Tunnel is one of the wonders of the modern world. It is thirty-two miles long at an average depth of 45 metres below the sea-bed, the longest undersea tunnel and the second longest rail tunnel in the world (only the Seikan Tunnel in Japan is longer). ). It was built between 1987 and 1994 by Anglo-French consortium TransManche Link and is owned and operated by Anglo-French Eurotunnel plc
