Excavation of the Qingdao Jiaozhou Bay Second Tunnel – China’s longest undersea road tunnel – was completed last week.
The 14.37km main tunnel section is the core of the 17.48km project that will connect Qingdao’s main urban area with the Qingdao West Coast New Area. The tunnel section comprises two bores and a service tunnel, with three lanes in each direction and a design speed of 80km per hour.
The breakthrough occurred 105m beneath sea level in Jiaozhou Bay, eastern China’s Shandong Province.
Wang Junping of the China Railway 14th Bureau Group Corporation, said the project used a combination of drill-and-blast and shield tunnelling methods, advancing from both the east and west shores of Jiaozhou Bay and meeting under the sea.
The main shield section has a maximum depth of 95m below the sea surface, and the service tunnel reaches 105m, creating high water pressure and requiring stringent sealing and waterproofing.
To improve efficiency and reduce blockage risks, the tunnelling team adopted a new muck discharge system, integrating a screw conveyor, rock crusher box and rock crusher. Anti-vibration technology was also developed for the shield body to improve stability.
Once completed, the new tunnel will help Qingdao form a multi-level cross-bay transport network together with the existing Jiaozhou Bay Tunnel, Jiaozhou Bay Bridge and Jiaozhou Bay Highway.
In July, China issued a plan to develop a modern integrated transport system during the 15th Five-Year Plan period (2026-2030).
Under the plan, China will improve connections among different modes of transport, make passenger transfers more convenient and enhance freight logistics services. It will also promote the integration of transport and tourism, improve services at transport hubs, and strengthen rural passenger transport, freight and delivery services.
