Work on the entrance to the Aren Shaft on the west coast of Tsushima has finally begun, and detailed surveys to establish the entrance were carried out for three days from May 4th to May 6th. A 200m long boring survey had already been carried out, and the small hole had become a landmark, but construction began when the excavator ``Backfour'' dug the small hole with a loud roar.
A tunnel entrance with a diameter of 6 m will be installed here, and the tunnel will move forward at an angle of 1 m after going 4 m. A few hundred meters away, we reach the Arian coast and the Korean Strait, and 60 km away is Geoje Island, South Korea, towards which we will head west along the ocean floor. Based on the survey results, the aim is to install the tunnel entrance by the end of July. Construction methods such as box culverts or liner plates will be considered, and full-scale construction will begin in June.
Two years ago, a road was constructed for construction vehicles to reach the site, and the site was cleared for use as an office, warehouse, material storage area, and equipment installation site. After that, a groundbreaking ceremony will be held by related parties, followed by construction. This time, the pit entrance will be located at the red and white landmark "Chobari" that you can see in the photo.
Tsushima has the same geology as the Korean Peninsula, and is a rocky island. There was little arable land suitable for growing rice, and ``Gishi Wajinden'' states, ``The land was steep, with many deep forests, and the roads were like the paths of birds and deer.There were over 1,000 households. ``Then they will board ships and spread the word north and south.''
Tsushima is a magnificent island that exists peacefully in the middle of the strong winds and rough waves of the Genkai Sea, and has connected Japan and Korea since ancient times. Even in modern times, the natural environment remains unchanged, and even airports have to be built on top of mountains. The geological formations are hard and the area is characterized by the absence of earthquakes. As construction progresses, modern civil engineering construction technology will uncover the geology of Tsushima.
International Highway Foundation Newsletter June 2014 issue (PDF viewing/download)