On August 6, after 213 days and nights, the Xinqiao Tunnel of the Chongqing-Kunming High-Speed Railway was successfully holed through, marking another refresh of the "progress bar" in the construction of the Chongqing-Kunming High-Speed Railway and laying the foundation for subsequent ballastless track construction and the completion and opening of the line to traffic.

The Xinqiao Tunnel has a total length of 353 meters. The construction area consists mostly of weak surrounding rock prone to deformation, bedding-parallel slope faces, and slope accumulations, with special rock and soil such as expansive soil and various other complex unfavorable geological conditions; in addition, four karst caves of varying sizes were successively encountered, making construction high-risk and highly difficult. The tunnel is located in the Maojiacun Reservoir Nature Reserve in Huize County. The builders adopted a combined method of "weak blasting + mechanical excavation" to successfully resolve the geological challenges, thereby both protecting the ecological environment and ensuring the schedule milestones.

According to reports, to ensure the safe and smooth holing-through of the tunnel, the project team started from the aspects of planning and construction support, strictly maintained duty shifts, strengthened technical guidance and emergency preparedness, and continued to implement the system of Party member-assigned responsibility work zones and daily safety inspections led by leadership on duty. At the same time, in accordance with construction progress, they worked backward from the schedule, refined the milestones, and deployed sufficient operating personnel to ensure that the established excavation tasks were completed with quality and quantity every day.

After the Chongqing-Kunming High-Speed Railway is completed and opened to traffic, it will further improve the national comprehensive three-dimensional transportation network. The travel time from Chongqing to Kunming will be shortened from nearly 5 hours at present to 2 hours, greatly improving travel conditions for people along the line and promoting high-quality economic and social development along the route.