The 5.76km-long tunnel is part of the Seo-myeon Namhae–Shindeok Yeosu National Road Project – a new 8.09km four-lane highway connecting Shindeok-dong in Yeosu and Seomyeon in Namhae on the country’s southern coast. The total project value is US$540m.

The project master plan centred on a unidirectional southbound route, linking Shindeok-dong in Yeosu to Seosang-ri in Namhae. DL E&C, however, proposed a divergence tunnel to connect the north-western region of Namhae to the existing infrastructure to help promote economic growth and tourism.

DL E&C says it used smart construction technology to design the tunnel, including its in-house BIM Tunnel Design Package and AI-based Generative Design to analyse the subsea conditions.

In the tunnel construction the company will use its insulation and fire-resistant concrete, which it says reduces thermal conductivity by 40% compared to conventional concrete.

It has also proposed digital technologies for safety measures, including a 24-hour integrated control and safety platform, a convergence smart measurement system, and smart construction equipment.

DL E&C says technological developments are opening up the possibility of undersea tunnels connecting Korea to Japan and China.