The Seikan Tunnel (Seikan Tonneru 青函 トンネル or 青 函 隧道 Seikan Zuid) is the longest railway tunnel in the world. Is 53 km, with a portion of 23.3 km below the seabed. Link Honshu to Hokkaido in Japan. Opened in 1988. It is 100 m under the sea and 240 m below sea level. It took 25 years to build it.
青 函 name (Seikan) is a contraction for the names of major cities on each side of the tunnel. The first character is 青森 (Aomori) and the other 函馆 (Hakodate). Link
Tsugaru Strait - connecting Aomori Prefecture on the Japanese island of Honshu and Hokkaido Island - as part of Japan Railways Kaikyo Line. Although it is the longest railway tunnel in the world, air travel is faster and cheaper, which has left relatively unused Seikan Tunnel.
Map Seikan Tunnel.
From the Taisho period (1912-1925) is considered to connect the islands of Honshu and Hokkaido by an overland route, but started serious exploration only since 1946, following the loss of overseas territories at the end of World War II and the need to accommodate the refugees who returned to Japan. In 1954 five ferries, including the Toya Maru sank in the sea during a typhoon, killing 1,430 passengers. The following year, the Company of Japan National Railways (JNR) began exploring for its construction.
also influenced the increase in travel between the islands. An economy growing traffic levels rose in the Seikan Ferry operated by JNR, doubling to 4,040,000 people per year from 1955 to 1965, charging rates grew 1.7 times to 6,240,000 t / year. In 1971, traffic information predicted that growth would exceed the capacity of the ferry port limited by geographical conditions. In September 1971 he decided to build the tunnel. The arduous and dangerous construction in difficult conditions, killing 34 workers.
On January 27, 1983 Japanese Prime Minister Yasuhiro Nakasone pressed the button that caused the explosion to complete the pilot tunnel. Also on 10 March 1985 the Minister of Transport Yamashita Tokuo symbolically pierced the main tunnel.
However, the project's success was questioned. The 1971 traffic forecasts were overstated. Although it increased in 1985, peaked in 1978 and then was in decline - attributed to lower economy since the oil crisis in 1973 and the advances made in aviation and maritime transport.
The tunnel was opened on March 13, 1988, at a cost of 538,400 million yen (U.S. $ 3,6 billion).
Once the tunnel was completed, all rail transport between Honshu and Hokkaido used the tunnel. Anyway, 90% of air passenger transport was due to the speed and cost. For example, travel between Tokyo and Sapporo by train takes more than 10 hours and 30 minutes, with several transfers. By air, the trip takes 3 h 30 min, including airport access times. Also, deregulation and competition on domestic flights down prices in the Tokyo-Sapporo route, making the train more expensive comparatively.
Tunnel entrance on the island of Hokkaido.
section of the tunnel.
Prospecting, construction and geology
The survey began in 1946. In 1971, 25 years later, construction began. In August 1982 there were less than 700 m to be excavated. The first contact between the two sides was in 1983.
The Tsugaru Strait has eastern and western necks, both 20 km long. The survey started in 1946 indicated that the eastern neck was more than 200 m deep, volcanic geology. The western neck has a maximum of 140 m and a geology consisting of sedimentary rocks Neoceno period. The western neck was finally selected because their conditions were optimal for the construction of a tunnel.
The geology of the portion of the tunnel that is under the sea is of volcanic rock, pyroclastic rock and sedimentary rock of the Late Tertiary. The area is in a vertical slope anticline, which means the latest rock is at the center of the layer. Can be divided roughly into three parts: the side Honshu volcanic rocks consisting of (ansesita, basalt, etc..) Hokkaido side with sedimentary rocks (Tertiary period) and the central portion consisting of stratum Kuromatsunai (similar to sand Tertiary Period). 8 The igneous intrusions and faults caused the breakage of rock and complicated the
trabajos.6 initial geological investigations were carried out between 1946 and 1963, and involved the drilling of the seabed, sonic testing, underwater observations (with mini-submarines) , seismic and magnetic evidence.
tunnel piercing made simultaneously from the north and the south side. The construction was carried out on the ground with traditional techniques of tunneling into mountains, with a single tunnel principal.6 But for the 23.3 km portion under the sea three tunnels were dug at increasing diameters, respectively: initial pilot tunnel, a service tunnel and finally the main tunnel. The service tunnel is bound to the main tunnel with a series of connectors, at intervals of 600 - 1000 M.8 The pilot tunnel is used to service the 5 km of the central portion. Close
Tsugaru Strait stopped using a drilling machine (TBM) after less than 2 km because of the variable density of the rock in place, making it accessible for drilling. The methods of excavation were dynamite and drilling manual.
Profile tunnel. (2) and (3) stations are underwater.
A 2002 report described Michitsugu Ikuma, for the section under the sea, that "the structure of the tunnel is apparently in good condition" .9 The number of leaks have been declining over time, although "increases the risk during an earthquake."
Structure
Currently, only narrow cross rail tunnels, but the Hokkaido Shinkansen project (which began construction in 2005) will include the laying of rails and dual tunnel will connect the Shinkansen network, so that trains Shinkansen may pass through the tunnel to Hakodate (scheduled for 2015), and eventually to Sapporo. The tunnel is 52 km of continuous rails without soldadura.10
Two stations are connected to the tunnel: Tappi-Kaitei Station and Yoshioka-Kaitei Station. The stations serve as emergency escape points. In the case of fire or other disaster, the stations provide security equivalent to another shorter tunnel. The effectiveness of exhaust outlets located in the emergency stations increases output by fans absorb the smoke, television cameras to guide passengers to the exit, alarms, thermal (infrared) and pitchers agua.4 Previously, both stations have museums detailing the history and function of the tunnel, and can be visited in special tours. Tappi-Kaitei only now remains as a museum, Yoshioka-Kaitei was demolished on March 16, 2006 to make way for the preparations of Hokkaido Shinkansen11 The two stations were the first in the world to be built under the sea.
train approaching the station Tappi-Kaitei.
CI Yoseph BUITRAGO 18257871 CRF
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