World Amazing Stuff: World's longest undersea tunnel

World's longest undersea tunnel

China plans for world's longest undersea tunnel

At more than twice the length of the Channel Tunnel underneath Bohai Bay. A 76 mile long tunnel will run between the northern city of Dalian and Yantai, on the east coast, China.

"The work could begin as early as 2015 or 2016," said an expert at the Chinese academy of Engineering, to the China Daily.

He added that the new tunnel will knock 80 miles off the current route between the two cities.
It will also form a vital link in a high-speed rail line from China's frozen north to the tropical island of Hainan, in the south.

China has a history of epic engineering projects stretching back to the Great Wall. More recently it has built the world's largest high-speed railway network, longest bridges, World's largest building and several of its tallest skyscrapers.

The new £22 billion sea tunnel will present several challenges. Engineers will attempt to bore three tunnels, one for cars, one for trains and one for maintenance through the hard rock, 100ft below the sea bed. Vertical shafts will be dug on islands along the route to provide ventilation.

Longest transport tunnels in the world 
  1. Gotthard Base Tunnel, Switzerland – land railway tunnel beneath Alps connecting Uri and Ticino, opens 2016 – 35.5 miles
  2. Seikan Tunnel, Japan – undersea railway tunnel connecting islands of Honshu and Hokkaido, opened 1988 – 33.5 miles
  3. Channel Tunnel, UK/France – undersea railway tunnel connecting Folkestone and Coquelles, opened 1994 – 31.4 miles
  4. Lötschberg Base Tunnel, Switzerland – land railway tunnel beneath Alps connecting Berne and Valais, opened 2007 – 21.5 miles
  5. New Guanjiao Tunnel, China – land railway tunnel beneath Guanjiao Mountains connecting Xining and Golmud, opens 2014 – 20.3 miles