The Channel (Chunnel) Tunnel
Dr. R Kuberan, Ms. Sudeshna Mukherjee
2. The project cost £4.65 billion (equivalent to £12 billion today), 80 per cent more than expected. Construction took six years (1988- 1994).
3. It was recognized as one of the “Seven Wonders of the Modern World” by the American Society of Civil Engineers, alongside the Empire State Building, the Itaipu Dam in South America, the CN Tower in Toronto, the Panama Canal, the North Sea protection works in the Netherlands, and the Golden Gate Bridge in San Francisco.
4. The first proposal for a tunnel under the Channel was put forward by Albert Mathieu, a French engineer - it included an artificial island half-way across for changing horses.
5. At the height of construction, 13,000 people were employed. Ten workers - eight of them British - were killed building the tunnel.
6. Englishman Graham Fagg and Frenchman Phillippe Cozette carried out the ceremonial break through on December 1, 1990.
7. They didn’t quite meet in the middle - the English side tunneled the greater distance.
8. The average depth of the tunnel is 50 metres below the seabed, and the lowest point 75 metres below. Much of the chalk marl spoil bored on the English side was deposited at Lower Shakespeare Cliff in Kent, now home to the Samphire Hoe Country Park.
9. There are actually three tunnels down there - two for trains and a smaller service tunnel that can be used in emergencies.
Dr. R Kuberan10. Up to 400 trains pass through the tunnel each day, carrying an average of 50,000 passengers, 6,000 cars, 180 coaches and 54,000 tonnes of freight.
Ms. Sudeshna Mukherjee
Civil Engineering and Construction Review
11. Three fires have occurred (in 1996, 2006 and 2012) inside the tunnel that was significant enough for it to close. The most serious, on November 18, 1996, damaged 500 meters of the tunnel, affecting operations for six months. An automatic fire dousing system has now been installed.
12. A number of train failures have occurred. On December 18, 2009, five Euro star trains broke down, trapping 2,000 passengers for 16 hours without power, and many without food or water.
13. In 2014 a record 21 million passengers were transported between Britain and France using the tunnel - up from 7.3 million in 1995, its first full year in operation.
14. Shuttle trains are 775 meters long - the same as eight football pitches.
16. It takes around 35 minutes to travel the length of the Channel Tunnel.
Surveying undertaken in the 20 years before construction confirmed earlier speculations that a tunnel could be bored through a chalk marl stratum. The chalk marl is conducive to tunnelling, with impermeability, ease of excavation and strength. The chalk marl runs along the entire length of the English side of the tunnel, but on the French side a length of 5 kilometres (3 mi) has variable and difficult geology. The tunnel consists of three bores: two 7.6-metre (25 ft) diameter rail tunnels, 30 meters (98 ft) apart, and 50 kilometres (31 mi) in length with a 4.8-metre (16 ft) diameter service tunnel in between. The three bores are connected by cross-passages and piston relief ducts. The service tunnel was used as a pilot tunnel, boring ahead of the main tunnels to determine the conditions. English access was provided at Shakespeare Cliff, French access from a shaft at Sangatte. The French side used five tunnel boring machines (TBMs), the English side six. The service tunnel uses Service Tunnel Transport System (STTS) and Light Service Tunnel Vehicles (LADOGS). Fire safety was a critical design issue.
Between the portals at Beussingue and Castle Hill the tunnel is 50.5 kilometres (31 mi) long, with 3.3 kilometres (2 mi) under land on the French side and 9.3 kilometres (6 mi) on the UK side, and 37.9 kilometres (24 mi) under sea. It is the third-longest rail tunnel in the world, behind the Gotthard Base Tunnel in Switzerland and the Seikan Tunnel in Japan, but with the longest under-sea section. The average depth is 45 metres (148 ft) below the seabed. On the UK side, of the expected 5 million cubic metres (6.5×106 cu yd) of spoil approximately 1 million cubic metres (1.3×106 cu yd) was used for fill at the terminal site, and the remainder was deposited at Lower Shakespeare Cliff behind a seawall, reclaiming 74 acres (30 ha) of land. This land was then made into the Samphire Hoe Country Park. Environmental impact assessment did not identify any major risks for the project, and further studies into safety, noise, and air pollution were overall positive. However, environmental objections were raised over a high-speed link to London. Working from both the English side and the French side of the Channel, eleven tunnel boring machines or TBMs cut through chalk marl to construct two rail tunnels and a service tunnel. The vehicle shuttle terminals are at Cheriton (part of Folkestone) and Coquelles, and are connected to the English M20 and French A16 motorways respectively. Tunnelling commenced in 1988, and the tunnel began operating in 1994. In 1985 prices, the total construction cost was
- The Channel Tunnel consists of two rail tunnels and one service tunnel, each 32 miles (51 kilometres) in length.
- The “Chunnel” connects Folkestone in Kent, England, with Coquelles in Pas-de-Calais, France.
- Many of the tunnel boring machines used on the Chunnel were as long as two football fields and capable of boring 250 feet a day.
- At its lowest point, it is 250 feet deep and at 24 miles long, the tunnel has the longest undersea portion of any in the world.
- When construction began, British and French tunnel workers raced to reach the middle of the tunnel first. The British won.
- The chalk marl excavated from Chunnel was used to create Samphire Hoe Park, a 74 acre nature reserve in Kent England.
Surveying undertaken in the 20 years before construction confirmed earlier speculations that a tunnel could be bored through a chalk marl stratum. The chalk marl was conducive to tunnelling, with impermeability, ease of excavation and strength. On the English side the chalk marl ran along the entire length of the tunnel, but on the French a length of 5 kilometres had variable and difficult geology. The tunnel consists of three bores: two 7.6-metre diameter rail tunnels, 30 metres apart, 50 kilometres in length with a 4.8-metre
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