The Sasago Tunnel, one of the longest tunnel in Japan that connects Tokyo to Nagoya, collapsed on December 2, 2012 causing deaths, injuries and damage to properties. Built in 1977, the Sasago tunnel is located west of Tokyo and passes through the hills near Mount Fuji.
Nine people died when they were trapped in their vehicles by the ceiling panel that crashed from the tunnel roof.
It took almost 3 hours to start the rescue operation due to poor visibility caused by black smokes coming from the collapsed tunnel. There is still fear that the 5 km tunnel may continue to collapse as the structure lost its stability.
Recent investigations revealed that the “anchor bolts” of the tunnel may have been the cause of the collapse. These bolts are used to fasten the concrete slabs to the tunnel ceiling.
Interesting facts about tunnels
Tunnels are underground passageway for traffic, be it vehicular, rail or for pedestrian. Some tunnels are also used for water supply, telecommunication cables, hydroelectric stations and even for sewers.
The first tunnel was built between 1825 and 1843 in London. The Thames Tunnel is the first underwater tunnel and measures 396 meters in length and 23 meters below the famous Thames River.
Here are some of the worlds longest tunnels:
- Seoul Subway Line 5
This tunnel is found in South Korea. It serves as a transit tunnel that was built in 1995. The tunnel’s length is about 47,600 meters in length. It is considered as the world’s second longest fully underground subway line.
- Channel Tunnel
Located in United Kingdom, Channel Tunnel is recorded to be the world’s longest undersea portion of any tunnel and second largest railway tunnel. This railway tunnel was built in 1994 and is about 50,450 meters in length.
- Orange-Fish River Tunnel
The water supply tunnel was built in 1972 in South Africa. It is the longest in southern hemisphere with a length of 82,800 meters.
- Laerdal Tunnel
Located in Norway, the Laerdal tunnel is considered the longest road tunnel in the world. It was built in year 2000 and has a length of 24,510 meters.
- Lotschberg Base Tunnel
This railway tunnel was built in 2007 and located in Switzerland. It is the world’s longest land tunnel and a railway single track with a length of 34,577 meters. Both passenger and freight trains use this tunnel which passes through the Swiss Alps.
- Seikan Tunnel
This rail tunnel is found in Tsugaru Strait, Japan. It was built in 1988 with a length of 50,450 meters. It is currently the world’s longest and deepest rail tunnel.