The longest sea-bed subway tunnel in the east China city of Qingdao opened to traffic on Thursday.
The 5.4-km-long tunnel between the stations of Dayang and Qingdao North is part of the Subway Line 8 project in the city.
The eastern side tunnel was dug by the slurry shield method, while the western side, by the mining method, according to the chief engineer of the project with the China Railway Group, the company responsible for the construction.
It took two years and seven months to complete the tunnel, a new record for similar subway projects.
The tunnel has surpassed the tunnel of the Qingdao’s Subway Line 1, which has 3.49 km of the line undersea, becoming the longest sea-bed subway tunnel in China, according to the China Railway Group and the Qingdao Metro Group, operator of the subway lines.
The Subway Line 8, which runs 61.4 km with 18 stations, will connect the international airport of Jiaodong and the railway stations of Jiaozhou North, Hongdao and Qingdao North, linking the city proper of Qingdao, the economic zone of Hongdao and the city of Jiaozhou.
With the opening to traffic, the tunnel will give a strong impetus to the integration and coordinated development of the China-Shanghai Cooperation Organization (SCO) demonstrative zone and the Jiaodong Economic Sphere.