BORYEONG UNDERWATER TUNNEL

[Anchor Lead]

Construction has been completed at the country's longest undersea tunnel. Both tubes of the Boryeong Undersea Tunnel have been penetrated seven years after ground was first broken for the project. At a length of 6.9 kilometers, it's the world’s fifth longest underwater tunnel and is slated to open in 2021.

[Pkg]

[Soundbite] "Blast!"

With an explosive sound, the soil clogging the tunnel's mid-section is blown out. It's the moment the Boryeong Undersea Tunnel on National Highway 77 is completely penetrated. The tunnel links Daecheonhang Port in Boryeong, Chungcheongnam-do Province and Wonsando Island on the West Sea. Excavation work began on both sides of the tunnel in November 2012. The tube bound for Wonsando was penetrated this February and the other tube is now also opened. The entire construction took 7 years. At 6,927 meters, the Boryeong tunnel is the world's fifth longest underwater tunnel. Locally, it's about 1.5 kilometers longer than the Incheon Bukhang Tunnel the previous record holder at 5.46 kilometers. As the tunnel is constructed as deep as 80 meters below sea level, a number of technologies were required to ensure safety and to prevent seawater leakage.

[Soundbite] LEE SANG-BIN(SUPERVISORY OFFICIAL) : "The thickness of the concrete is greater than ground tunnels at over 40cm and concrete strength has also been raised from 21 to 40MPa."

One amazing feat was having excavators that began work from the opposite sides meet exactly at the tunnel's center. Once road construction connecting Boryeong and Taean is completed, travel time will be drastically reduced from the current 90 minutes to just 10.