The Channel Tunnel
An undersea linkage between southern England and northern France, the channel tunnel, “Chunnel”, or “Eurotunnel, is under the authority of the UK and the Republic of France, where it started operation in 1994 with a capital value of GBP 9.5 billion (11.8 USD Billion). It’s a water crossing, a fixed link that connects the island of Great Britain to the mainland.
It is the only fixed connection between the United Kingdom and the European continent. It plays a leading role among the transport channels, not only between the centre of the British Isles and the ultimate area in the north and northeast of France (Lille), but also, in terms of high-speed train travelling, between the whole of the United Kingdom and Brussels, Paris, and the major cities in France. As the ‘ordinary railway through the tunnel’ is approved for journeys from and to England, one can term the tunnel (as a part of the European system) the connection between Belfast and Lille on the one hand, and between Lille and Oostende on the other.
History and Timeline
Starting in the early 19th century, the project aimed to overcome geographical challenges. In Europe’s transportation axis, represented by the route London-Brussels-Amsterdam, the connection between the United Kingdom and the European continent has always constituted a problem for transportation infrastructures, and consequently for the transfer of passengers and goods. In 1984, several leading European countries signed a treaty in agreement with the construction of a fixed link beneath the Channel. In quick succession, the feasibility study, further studies, and international research were followed by tests on different scales. The idea gained momentum with the UK and France calling for proposals in 1985. Four were shortlisted:
- Euroroute, a hybrid solution of a bridge-tunnel-bridge (GBP4.8 billion – about USD6.2 billion, 1985 prices)
- Europont, a suspended bridge (GBP5 billion – about USD6.5 billion)
- Transmanche Express, four bored tunnels allowing both railway and road traffic (GBP2.5 billion – about USD3.3 billion)
- Eurotunnel, a rail shuttle service for road vehicles with provision for through trains using three tunnels (GBP2.6 billion – about USD3.4 billion).
Based on this research, the Channel Tunnel was equipped with transmission infrastructures in the maritime area, the English marshes, and the French regions and positioned beneath the Calais sandbanks.
Description
The tunnel consists of three interconnected tunnels (50.5 kilometres long and 7.6 in diameter), the north bore, the south bore, and the Crossover – two for rail traffic and a smaller service tunnel. It is on the latter (Crossover) that the single-track running tunnels of 33510m length hold sway and embrace ‘technically advanced’ services. Using Optic Fiber Detection (OFD) systems, which can work at distances as long as 40km to warn the smallest sign of smoke, the tunnel was built with extreme caution and security control. The three tunnels run parallel to each other.
Construction
The tunnelling methods included both traditional drilling and the use of specialised tunnel boring machines (TBMs) to excavate through the chalk marl beneath the seabed. This method was able to minimise environmental hazards and reduce construction time in comparison to traditional cut-and-cover methods.
It has a very powerful telecommunications system because of the need to ensure reliable communication systems, thus supporting train control as well as wayside equipment over long distances. The Central Section or Crossover has the 50Hz Required Power Supply, which is very extensive in complex loads as well as bringing under various conditions power to a 3000V DC power system on the Running Tunnels. The technical elegance of the Channel Tunnel is considered a benchmark in Europe for future high-speed links since it is the largest modular-designed tunnel in the world.
Structural Design
Despite the high pressure and challenging conditions beneath the seabed, the construction method of using precast concrete segments allowed for an efficient assembly. They are assembled on-site to form rings that line the tunnel walls.
Integration with Existing Infrastructure:
The architectural design of the Channel Tunnel integrates seamlessly with existing transportation infrastructure in England and France. On the English side, the tunnel connects to the High Speed 1 rail line, providing direct access to London and other major cities. On the French side, the tunnel connects to the French railway network.
It reduces travel time between England and France where high-speed Eurostar trains can cross the tunnel in approximately 35 minutes and it can accommodate up to 400 trains per day.
The cross-country project stands as a triumph of modern engineering. Its innovative design, safety features, and integration with transport networks have transformed cross-channel travel, reducing journey times and enhancing connectivity. As an iconic landmark, it serves as a testament to the possibilities of ambitious engineering construction. It is considered one of the most successful, highly innovative, and reputed public-private projects, which spanned the Anglo-French waterway.
References:
The Channel Tunnel: Euro Tunnel. Eurostar. (n.d.-a). https://www.eurostar.com/rw-en/travel-info/eurostar-experience/the-channel-tunnel
Global Infrastructure Hub. (2020, November 30). The Channel Tunnel. Global Infrastructure Hub – A G20 INITIATIVE. https://www.gihub.org/connectivity-across-borders/case-studies/the-channel-tunnel/#:~:text=The%20Channel%20Tunnel%20is%20a,Britain%20and%20the%20European%20mainland
Encyclopædia Britannica, inc. (2024, March 11). Channel Tunnel. Encyclopædia Britannica. https://www.britannica.com/topic/Channel-Tunnel
The Channel Tunnel | Institution of Civil Engineers (ICE). (n.d.-a). https://www.ice.org.uk/what-is-civil-engineering/what-do-civil-engineers-do/the-channel-tunnel
The Channel Tunnel – interesting facts. LeShuttle. (n.d.). https://www.eurotunnel.com/uk/build/
Channel Tunnel. Channel Tunnel | Office of Rail and Road. (n.d.). https://www.orr.gov.uk/monitoring-regulation/rail/networks/channel-tunnel
