After more than three years of arduous efforts by builders, as of now, excavation and support for the longest tunnel on the entire Guiyang-Nanning High-Speed Railway—the first high-speed railway in Southwest China designed for a speed of 350 kilometers per hour—has exceeded halfway. The subgrade earthwork and the offline works of 7 bridges in Section 6 of the pre-station works on the Guizhou section have been basically completed, marking another big step toward the overall completion of the entire section.

Section 6 of the Guizhou section of the Guiyang-Nanning High-Speed Railway is located in Libo County, Qiannan Autonomous Prefecture, with a total length of 23.866 kilometers. The construction task is undertaken by the Guiyang-Nanning High-Speed Railway Project Department of China Railway 18th Bureau. The entire section includes 2 tunnels totaling 17,236 meters and 7 bridges totaling 4,829.881 meters, including 2 extra-large bridges totaling 3,857.8 linear meters.

As of now, the excavation and filling for Libo High-Speed Railway Station have been completed, and the remaining ancillary works are under full construction. In the subgrade works of the entire section, the subgrade earthwork has been basically completed, and subgrade ancillary works are under construction. In the bridge and culvert works, the offline works of the 7 bridges (including pile foundations, piers and abutments, etc.) have been basically completed, and beam erection is expected to be fully completed by December 30, 2021.

It is particularly worth mentioning that although Section 6 has few tunnels, the longest tunnel on the entire Guiyang-Nanning High-Speed Railway (including the Guizhou and Guangxi sections)—the 17,012-meter (17.012-kilometer) Jiuwandashan No. 1 Tunnel—is located within Libo County under the jurisdiction of this section. This is a key control project of the Guiyang-Nanning High-Speed Railway. At present, excavation and support for this tunnel have cumulatively completed more than 9,000 meters, accounting for more than 53% of the designed length of 17,012 meters. It is expected to break through in January 2022 and be completed in May of the same year.

In addition, the Libo Zhangjiang Multi-Track Extra-Large Bridge has a total length of 1,719 meters and a maximum pier height of 32.5 meters. Among them, the continuous beam for the turnout from six tracks to double tracks spans from Abutment 0 to Pier 7, with a single concrete pouring volume of more than 2,400 cubic meters, making pouring difficult. Piers 16 and 17 are located in the Zhangjiang River, posing greater construction difficulties and high safety risks. Some bridge piers also cross tourist roads in Libo County and are situated in complex terrain, placing higher requirements on the safe construction of the bridges.

The Laocun Double-Track Extra-Large Bridge has a total length of 2,138.8 meters and a maximum pier height of 49 meters. Its superstructure consists of 65 spans of 32-meter simply supported box girders. Due to terrain constraints, the entire bridge deck is cast in place using a movable scaffolding system. Geological drilling shows that the bridge is located in a karst development area, and pile foundation construction encountered 60 underground karst caves, the largest of which is 9 meters deep.

It is expected that by the end of 2022, all bridge and culvert, tunnel, ballastless track, and other engineering projects in this section will be completed, laying a solid foundation for the full completion of the Guiyang-Nanning High-Speed Railway in 2023.

　　The Guiyang-Nanning High-Speed Railway is located in Guizhou and Guangxi provinces (regions). It is a component section of the Baotou-Haikou Corridor (Baotou-Haikou) of the "Eight Vertical and Eight Horizontal" high-speed railway network in China's "Medium- and Long-Term Railway Network Plan." The newly built line has a total length of 481 kilometers, of which the Guizhou section is 199.64 kilometers long and started construction at the end of December 2017.

　　After the entire Guiyang-Nanning High-Speed Railway is opened, the fastest railway travel time from Guiyang to Nanning will be reduced from the current more than 5 hours to less than 2 hours, playing an important role in promoting rural revitalization and high-quality economic and social development along the line.