(Photo/xmnn.cn)

The construction of the central part of China’s first under-sea shield tunnel for the Line 2 subway in Xiamen, east China’s Fujian Province, was completed on March 21, xinhuanet.com reported.

Rail tracks of the cross-sea subway line have all been laid successfully, according to China Railway Construction Corporation Limited (CRCC).

Two balance slurry-type shield tunneling machines with a diameter of 7 meters were used during the construction of this 2,760-meter-long under-sea tunnel, which crosses the busy main course of the west harbor of Xiamen and the Xiamen International Cruise Terminal, said Wang Xiaoqiong, project manager of China Railway 14th Bureau Group Co. Ltd, the project contractor.

The geological conditions of the strata through which the tunnel has been built are complex and variable, said Wang, adding that the area has been referred to as “a museum of geology”.

An expert team led by Qian Qihu, an academician from the Chinese Academy of Engineering (CAE), visited the construction site a number of times to offer advice on the construction and perfect the design.

The project adopted more than 20 new technologies and methods, offering experience for China’s future efforts in the construction of under-sea shield tunnels and dealing with complex geological problems.