- The Channel Tunnel, also commonly referred to as the Chunnel, is a made underground passage which travels under the English Channel, connecting England and France. The tunnel spans over 30 miles, and plunges over 250 feet underground in order to travel beneath the seawater of the Channel. The idea of linking France and England with a tunnel existed at least a hundred years before the tunnel was successfully built. In the 1800's, the beginning of a tunnel was started but abandoned due fears that a tunnel would allow the French or other mainland European nations to invade England. Construction on the tunnel resumed in the 1970's, but political and economic concerns halted construction. It wasn't until 1987 that excavation resumed, and the Chunnel was finally completed in 1994. Early surveying and excavation done in unsuccessful attempts aided tunnel engineers in its completion.
- The goal prescribed for the Chunnel was to create two parallel rail tunnels, and a smaller service tunnel in between the rail tunnels. The majority of the Channel Tunnel was bored out through chalk and clay with several large tunneling machines, which begin drilling from Folkestone England and from Coquelles France. Tunneling machines are essentially giant drills which can chew up rock and sediment, allowing it to be removed from the tunnel. As the machines bored, the tunnels behind them were reinforced with rings of concrete, creating a lining for the tunnel. The machines continued boring on a precisely calculated path until they close enough for workers to use air powered drills and other tools to finally create a hole connecting the two sides and clear out the tunnel.
- After the tunnel linked, it was fully reinforced with concrete and rail lines were built through it. The trains are used to transport freight and passengers though the tunnel, a trip which only takes about 35 minutes. The Chunnel has serviced over 100 million passengers since its creation, and carried over 100 million tons of tons of freight, though the construction costs were higher than initial estimates, and passenger usage of the tunnel since its creation has been lower than what officials had hoped for. Still, the Chunnel is an important transportation artery for England and France, which may see increased use in the future since the prices of air and sea travel are more dependent upon oil prices and availability.
