Boryong-Taean National Highway Construction Project, South Korea

The Boryong Tunnel is an extended section of the Route 77 connecting Daecheon Port and Wonsando Island, and has a total length of 7.985 km. It is initially planned to facilitate the development of tourist attractions and to improve the living environment of the nearby island residents. Furthermore, it is also expected to improve the development of local area and accompanying traffic congestions.

The Boryong Tunnel (L=6,927 m), which is the first excavated submarine road tunnel in South Korea, is a two lane tunnel. The length of the undersea section is 5.1 km with a maximum water depth of 37 m in this area. The overburden thickness lies between 30 m and 55 m, where the rock mass thickness is around 25 m.