China has finished all shield-driven excavation on the Jiaozhou Bay Second Tunnel beneath Jiaozhou Bay in Shandong Province, eastern China, China Railway Construction Corporation said on Friday, October 2, 2026. The milestone completes the longest subsea road tunnel drive anywhere in the world to date, according to the company and reporting by People’s Daily and Tunnels and Tunnelling magazine.
The Jiaozhou Bay Second Tunnel in numbers
According to the project team, the crossing stretches 17.48 kilometres from shore to shore. The main tunnel section runs 14.37 kilometres and consists of two road bores plus a middle service tunnel. Each road bore carries three lanes of traffic, and the tunnel is designed for a travel speed of 80 kilometres per hour. The main shield-driven section reaches about 95 metres below the surface of the sea, while the service tunnel descends to about 105 metres. At such depths the works faced extreme water pressure, which the builders countered with strict sealing and waterproofing measures, the company says.
How the crossing was built
The China Railway 14th Bureau Group constructed the tunnel using a combination of drill-and-blast excavation and shield tunnelling, according to the company. Shield machines advanced from both shores of the bay and met beneath the sea, linking the two drives in the middle of the alignment.
New technology for a difficult drive
The project team reports that several new technologies were developed for the works. These include a muck discharge system that integrates a screw conveyor, a rock crusher box and a rock crusher, which the company says improved the removal of excavated material from the tunnel face. The team also introduced new anti-vibration technology for the shield body to keep the machines steady while boring through difficult ground. The drill-and-blast section of the project is now more than 90 percent complete, and the service tunnel is expected to be fully connected early next year, according to the company.
Why it matters
When finished, the tunnel will link Qingdao’s main urban area with the Qingdao West Coast New Area, a national-level new area on the far side of the bay, the company says. Together with the existing Jiaozhou Bay Tunnel, the cross-bay bridge and the expressway, it will form a multi-level transport network across the water. That network is expected to shorten journeys for commuters and freight, relieve pressure on the existing crossings, and support the economic development of the new area.
What happens next
The first Jiaozhou Bay Tunnel, which opened in 2011 with a length of 7.8 kilometres, was itself a major subsea road project, Tunnels and Tunnelling magazine reports. Construction of the Jiaozhou Bay Second Tunnel began in October 2020. With shield-driven excavation now complete, the project moves on to fitting out, which includes road surfacing, electrical and ventilation systems, and safety testing. Chinese media reports put the planned opening of the tunnel around 2027 to 2028.
Sources: People’s Daily and Tunnels and Tunnelling magazine.