On August 4, 2022, after more than 800 railway builders worked continuously for more than four years, the Dafangshan Tunnel of the Guinan High-speed Railway was successfully completed. Up to now, 43 of the 44 tunnels in the Guangxi section of the Guinan high-speed railway have passed through, and it is expected that track laying will begin in mid-August.

The Dafangshan Tunnel is located in the Huanjiang Maonan Autonomous County of Guangxi, with a total length of 9,647 meters. The area is a typical karst landform mountainous area with strong karst development. It is the tunnel with the highest rate of karst cave encounters in the Guangxi section of the Guinan high-speed railway.

"Because of the large number of karst caves in the tunnel, we have specially strengthened the lining structure for the weak part of nearly 1 km." said Zhang Jianbo, project manager of the Guinan High-speed Railway Project Department of China Railway 12th Bureau. The construction team also built a water collection gallery and a water culvert in the tunnel, and introduced the karst water into the sedimentation tank outside the tunnel for filtration, and discharged it after reaching the discharge standard, which not only protects the environment, but also provides convenience for the agricultural irrigation water of the surrounding residents.

The Guinan high-speed railway is an important part of the sea passage in China's eight vertical and eight horizontal high-speed railway network, and it is also the first high-speed railway in Guangxi with a design speed of 350 kilometers per hour. The entire line is expected to be put into operation by the end of 2023, and the travel time from Nanning to Guiyang will be shortened from the current five hours to about two hours.Editor/Ma Xue