4157 x 4157 px | 35,2 x 35,2 cm | 13,9 x 13,9 inches | 300dpi
Data acquisizione:
1 settembre 1989
Ubicazione:
Underground Rail Tunnel Folkestone UK
Altre informazioni:
One of the more challenging sections of the Channel Tunnel was a short area through Castle Hill (adjacent to the UK Eurotunnel Terminal at Folkestone) which was known to be geologically unstable. It was excavated using a roadheader (like a self-propelled drill) machine and the walls were stabilised by spraying with fast-setting concrete (called shotcrete). Later, the tunnel was lined with a waterproof membrane before the permanent concrete lining was installed. 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. It opened for business in late 1994, offering services including a shuttle train for car, coach and freight vehicles, a Eurostar high-speed passenger service linking London with Paris and Brussels and a rail freight service. The tunnel boring machines were specially designed for excavating the chalk marl rock which lies beneath the seabed along the tunnel route. Digging the tunnel took 15 thousand workers around 170 million man hours over 7 years with tunnelling happening simultaneously from both ends. The Channel Tunnel consists of three parallel tunnels. There are two rail tunnels carrying trains to and from the UK to France and a smaller access tunnel served by narrow rubber-tyred vehicles and connected by transverse passages to the main tunnels at regular intervals. It allows maintenance workers access to the tunnels and provides a safe route for escape during emergencies.
