The World's 5th Longest 'Boryeong Undersea Tunnel'... Fully Opening on the 1st of Next Month

Opened 11 Years After Construction Start... 488.1 Billion KRW Invested
Travel from Daecheon Beach to Anmyeondo Yeongmok Port in Just 10 Minutes

Interior view of Boryeong Undersea Tunnel (Photo by Ministry of Land, Infrastructure and Transport)

The 'Boryeong Undersea Tunnel,' which has rewritten the history of roads and tunnels in Korea as the country's longest undersea tunnel, will open on the 1st of next month, 11 years after construction began.

The Ministry of Land, Infrastructure and Transport announced on the 29th that the undersea tunnel on National Route 77, connecting Sinheuk-dong, Daecheon Port in Boryeong City, Chungnam, to Wonsando in Ocheon-myeon, will be fully opened from 10 a.m. on the 1st of next month.

The Boryeong Undersea Tunnel, completed with domestic construction technology, is the longest undersea tunnel in Korea and has rewritten the history of roads and tunnels in the country. Construction began in December 2010 and took about 11 years, with a total project cost of 488.1 billion KRW.

The Boryeong Undersea Tunnel is 6.9 km long, making it the fifth longest in the world. It follows Japan's Tokyo Aqua-Line (9.5 km), Norway's Bømlafjord (7.9 km), Norway's Eiksund (7.8 km), and Norway's Oslofjord (7.2 km).

Exterior view of Boryeong Undersea Tunnel (Photo by Ministry of Land, Infrastructure and Transport)

Of the total length of 6.9 km, the pure undersea section is 5.2 km long and is located up to 80 meters below sea level. During the construction of the undersea section, the NATM method, a blasting excavation technique, was introduced for the first time in Korea. To effectively block seawater inflow during construction, the IMG (Intelligent Multi-Grouting) system was developed, enhancing the status of Korea's construction technology.

Additionally, to ensure the tunnel's stability and durability, the thickness and strength of the concrete lining were reinforced compared to ordinary land tunnels, and safety was prioritized by applying corrosion-resistant rock bolts during construction.

Once the Boryeong Undersea Tunnel opens, it will connect with the Boryeong-Taean Section 2 (Wonsando to Anmyeondo), completed at the end of 2019, reducing the travel distance from Daecheon Beach to Yeongmok Port in Anmyeondo from 95 km to 14 km. The travel time will decrease from 90 minutes to 10 minutes, cutting 80 minutes.

Lee Yunsang, Director of the Road Bureau at the Ministry of Land, Infrastructure and Transport, said, "With the opening of the Boryeong Undersea Tunnel, National Route 77, which was previously disconnected by the sea, is now connected, forming a unified tourism and living area within 10 minutes between Boryeong and Taean. We expect not only improved convenience for residents and tourists but also smoother logistics handling."