JINAN, Aug. 25 (Xinhua) -- Drivers can now cross the Yellow River, China's second-longest river, in just about five minutes, as a new tunnel opened to traffic on Tuesday in Jinan, capital of east China's Shandong Province.
Stretching about 5.75 kilometers in total, the tunnel under Huanggang Road features a shield-driven section of roughly 3.3 kilometers, bored by the "Shanhe" shield tunneling machine with a cutting diameter of 17.5 meters, the largest of its kind among underwater shield tunnels in the country.
The single-tube, double-deck structure accommodates six lanes -- three on each level -- with a design speed of 60 kilometers per hour. "This layout makes full use of underground space resources, allowing two-way traffic with just one single bore by the shield tunneling machine, which significantly improves overall cost-effectiveness," said Zhang Tiyong, project director of Jinan City Construction Group, the project's investor.
The tunnel offers an internal clearance height of 4.2 meters, Zhang added, tall enough for buses, fire engines, and maintenance and rescue vehicles, greatly boosting cross-river traffic capacity between the southern and northern banks of the Yellow River.
According to Zhou Xiang, on-site project manager from China Railway 14th Bureau Group Corporation Limited, the project's constructor, the Yellow River section in Jinan is a typical "suspended river," with its bed rising about five meters above the urban area on the southern bank and complex geological conditions lying beneath the river.
"As the diameter of the shield tunneling machine increases, the engineering challenges and construction risks grow exponentially," Zhou said. Despite the extreme difficulties, the project team used intelligent, mechanized, and green technologies throughout construction to ensure safe, efficient boring.
Qian Qihu, an academician of the Chinese Academy of Engineering, said the successful application of these technologies will drive continuous progress in China's shield tunneling capabilities and mark a milestone for the country's underwater traffic tunnel construction.
The project also incorporates an intelligent rail-borne inspection robot equipped with a full suite of smart devices, including a 360-degree panoramic gimbal, infrared thermal imaging, and laser obstacle-avoidance radar, enabling fully autonomous inspection across the entire tunnel. In addition, the tunnel's fire suppression system has been upgraded with AI-powered image-based fire detection to markedly improve detection sensitivity and accuracy.
As the second major Yellow River crossing in Jinan after the tunnel under Jiluo Road, this new route is expected to further boost cross-river economic ties and accelerate the national strategy for the river's development and the construction of the city's pilot industrial transformation zone, local authorities said. ■
