China's longest undersea highway tunnel excavation completed
Beijing (ANTARA) - China’s longest undersea highway tunnel has completed its entire excavation process using a shield machine on Friday (2/10), after the machine reached its designated position at a depth of 105 metres below sea level in Jiaozhou Bay, Shandong Province, eastern China, China Railway Construction Corporation Limited revealed.
The second Jiaozhou Bay Tunnel in Qingdao will connect the main urban areas of Qingdao with the Qingdao West Coast New Area, a new national-level zone. The 17.48 km project includes a main tunnel section of 14.37 km, consisting of two main tunnels and one central service tunnel, featuring three lanes in each direction and designed for speeds of 80 km/h.
According to Wang Junping from China Railway 14th Bureau Group Corporation Limited, the project utilised a combination of the drill-and-blast method and shield machine excavation. Work was carried out from two points—the eastern and western coasts of Jiaozhou Bay—until the two tunnel sections met undersea.
The main shield section reaches a maximum depth of 95 metres below sea level, while the service tunnel reaches a depth of 105 metres, resulting in high water pressure that requires strict sealing and waterproof lining.
Wang stated that the project team utilised a new system for excavated material disposal for the first time. This system integrates screw conveyors, crusher boxes, and stone crushing machines, thereby increasing efficiency and reducing the risk of blockages, Wang noted. He added that the team also developed innovative anti-vibration technology for the shield machine body to enhance stability.
Once construction is complete, the new tunnel will assist Qingdao in forming a multi-level cross-bay transport network alongside the existing Jiaozhou Bay Tunnel, Jiaozhou Bay Bridge, and Jiaozhou Bay Highway.
China has published a plan to comprehensively advance high-quality development in the field of integrated transport services during the 15th Five-Year Plan period (2026-2030), as announced by China’s Ministry of Transport in July this year. The plan aims to essentially establish a modern integrated transport service system by 2030.
Under this plan, China will enhance intermodal transport connections, facilitate passenger movement, and improve goods logistics services. China also aims to promote the integration of transport and tourism, enhance services at transport hubs, and strengthen passenger, goods, and delivery services in rural areas.