As one of the most preferred modes of long-distance travel for the Chinese people, high-speed rail is continuously improving its network across the country, with construction gradually underway in various regions. On May 10, China Railway's official WeChat account announced that the Bifengsi Tunnel on the Fuzhou-Xiamen High-Speed Railway has been successfully holed through. As a first-class high-risk long tunnel on the entire line, its breakthrough lays a solid foundation for the line to meet the conditions for opening and operation in 2022.

The Fuzhou-Xiamen High-Speed Railway is China's first cross-sea high-speed railway designed for a speed of 350 km/h. The Bifengsi Tunnel, located in Fuqing City and Putian City of Fujian Province, has a total length of 8.4 kilometers and is the most difficult key control project on the entire line.

During construction, the tunnel had to pass through 8 fault fracture zones, 8 dense joint zones, and a 480-meter strongly water-rich area, with frequent water and mud inrushes. The maximum daily water inflow reached 7,800 cubic meters, making construction highly challenging.

The construction and contracting units comprehensively adopted technical means and construction methods such as ground-penetrating radar and 3D laser scanning to overcome difficulties including large water inflow and long-distance reverse-slope drainage, achieving water-free operations inside the tunnel and zero-error breakthrough of the ultra-long tunnel under complex geological conditions. This fills a technical gap in tunnel construction under complex geological conditions for 350 km/h high-speed railways in China.

It is worth noting that the Fuzhou-Xiamen High-Speed Railway is not only China's first cross-sea high-speed railway but also Fujian Province's first 350 km/h high-speed railway. It starts from Fuzhou in the north, passes through Putian and Quanzhou, and ends at Xiamen and Zhangzhou in the south, with a total length of 277.42 kilometers.

After the line is completed and opened to traffic, the travel time from Fuzhou to Xiamen will be shortened to less than one hour, creating a "one-hour living circle" between Fuzhou and Xiamen and connecting the three major cities of Xiamen, Fuzhou, and Quanzhou, which is of great significance for promoting economic and social development along the route.