On August 27, accompanied by a rumbling blast, good news came from the Panxing Railway construction site: the Qinghoushan Tunnel undertaken by China Railway No. 3 Engineering Group was successfully holed through. It is also the 13th tunnel holed through in Section 3 of the Panxing Railway, injecting a "shot in the arm" into the construction of the Panxing Railway.

The Qinghoushan Tunnel is located in Baotian Town, Panzhou City, Guizhou Province. The tunnel entrance is adjacent to Baotian Station of the Panxing Railway. It is a major, difficult and controlling project of Section 3 of the Panxing Railway. The tunnel has a total length of 2,502 meters, making it the longest tunnel in the section. Its risk level is Class II, and the design speed is 250 km/h. The maximum buried depth of the tunnel is 188 meters. The tunnel has 985 meters of Grade III surrounding rock, accounting for 39.3% of the total tunnel length; 835 meters of Grade IV surrounding rock, accounting for 33.3%; 645 meters of Grade V surrounding rock, accounting for 26%; and 37 meters of open-cut section, accounting for 1.4%. The tunnel has complex geological structures, passing through 3 faults and 1 fold structure. Karst is strongly developed in the tunnel area, weak swelling rock exists in the surrounding rock, and groundwater in the tunnel area is abundant and highly seasonal, with an inflow of 8,410 cubic meters per day in the dry season and up to 31,000 cubic meters per day in the rainy season.

Since the start of construction of the Qinghoushan Tunnel, it has gone through multiple tests including crossing fault and karst sections, encountering water and mud inrushes many times, and broken rock, with high safety requirements and great construction difficulty. The Panxing Project of China Railway No. 3 Engineering Group overcame the treatment of dangerous rocks at the portal and completed the overhead ditch, temporary protection of the side and face slopes, excavation of the vertical working face, construction of the guide wall, installation of the large pipe roof, and pipe roof grouting, meeting the conditions for tunnel entry. On April 5, 2021, construction started from the tunnel exit, and on May 22, construction started from the tunnel entrance, achieving two-way excavation of the tunnel. At the same time, the project followed the construction principles of "short advance, strong support, early closure," coordinated the deployment of personnel and equipment, ensured steady progress of the project, strengthened technical services, stayed at their posts, worked overtime, fought on the front line, and accelerated the excavation progress. On September 27, 2022, the drainage tunnel of the Qinghoushan Tunnel was holed through, laying a solid foundation for the safe discharge of water inflow in subsequent tunnel construction and reducing the risk of water inflow in the tunnel, marking a major breakthrough in the construction of the Qinghoushan Tunnel of the Panxing Railway.

To speed up tunnel construction and achieve tunnel holing-through on schedule, Section 3 of the Panxing Railway of China Railway No. 3 Engineering Group strictly implemented the leadership shift supervision system, strengthened control over important processes such as arch installation, initial support shotcrete, lining, and concrete pouring, and carried out 24-hour three-shift operations under the premise of ensuring safety, strongly guaranteeing the smooth holing-through of the tunnel. The holing-through of the Qinghoushan Tunnel this time provides a girder transport channel for subsequent box girder erection, advances the "acceleration" of Panxing Railway construction, and lays a solid foundation for striving to open as soon as possible the "road to happiness" long awaited by the people.

After the Panxing Railway is completed, Guizhou Province will realize the vision of "high-speed rail access in every city and prefecture," and a 1- to 2-hour high-speed rail transportation circle from Guiyang to the central cities of the province's 8 cities (prefectures) will be formally formed. It is of great significance for promoting regional economic integration, strengthening the internal economic circulation, consolidating the achievements of poverty alleviation, advancing rural revitalization, promoting regional economic and social development, and optimizing and improving the layout of the national railway network.