Summary：Employees lay track for the Xiamen Metro Line 2 in Xiamen, East China's Fujian Province, on MondayThe complet...

Employees lay track for the Xiamen Metro Line 2 in Xiamen, East China's Fujian Province, on Monday

The completion of China's first transmarine subway tunnel project conducted with shield tunneling technology in Xiamen, East China's Fujian Province, can serve as a reference for similar efforts, and it indicates the country's application of the technology has independently developed to a high level, analysts said Wednesday.

The transmarine subway tunnel project of the Xiamen Metro Line 2 in Fujian Province, which finished Sunday, was the first and most challenging transmarine subway tunnel project conducted with the key construction technology of shield tunneling in the country.

Shield tunneling technology was adopted on 2.5-kilometer section of the entire 2.7-kilometer tunnel, and the work took five years, China Railway Construction Corp said on Tuesday.

Shield tunneling is an excavation method that uses a shield as protection and support structure, and it is usually used when digging through unstable and soft ground. When one considers that it took five years to build 2.5 kilometers, the difficulty is obvious, analysts said. As the first project of its kind in China, there were no standards to follow.

According to chinanews.com, the construction risks posed by the geological conditions of the tunnel are "rarely seen" nationwide. The bedrock surface has a complex structure and is rife with fault zones.

He Huawu, a member of the Chinese Academy of Engineers, said that China's shield tunneling technology developed rapidly starting from scratch, and it has reached world-class levels in terms of underwater shield tunnel design, equipment manufacturing and safety construction, the Xinhua News Agency reported on October 24, 2018.

Construction began on December 30, 2014 as the starting point of the Xiamen Metro Line 2 project, which is 41.6 kilometers long and has 32 stations. According to a statement by Xiamen Rail Transit Group, it is expected that trial operations on Line 2 will commence at the end of 2019.