On September 1, after 1,194 days and nights of arduous efforts by the builders, the No. 1 inclined shaft and the entrance section of the Baoyun Tunnel in the Yungui section of the Chongqing-Kunming High-Speed Railway (Bid Section 5) were successfully holed through, laying a solid foundation for the breakthrough of the entire tunnel.

The Baoyun Tunnel of the Chongqing-Kunming High-Speed Railway is located in Huize County, Qujing City, Yunnan Province, with a total length of 16,797 meters. Among this, the small-chainage section of the main tunnel at No. 1 inclined shaft and the entrance section total 4,187 meters, making it a major and difficult project of the Chongqing-Kunming High-Speed Railway and a Class II risk tunnel. The tunnel passes through unfavorable geological conditions such as swelling rock and bedding bias, with complex and variable geological conditions and abundant groundwater. The tunnel body traverses multiple fault fracture zones, presenting unfavorable geology including low gas emission, large deformation of soft rock, bedding collapse, and landslides.

Following the construction strategy of "high quality, high efficiency, speed, and orderliness," the builders of the Chongqing-Kunming High-Speed Railway have deeply implemented a standardized management model, strictly managed procedures, refined construction processes, overcome difficulties such as complex geological structures, long material transport distances, and unstable climate and weather, and continuously improved the level of construction technology.

To ensure construction progress, the construction party has adopted measures such as clarifying tasks and strengthening assessments, vigorously tightened safety production, and strictly controlled construction quality.

The Chongqing-Kunming High-Speed Railway is an important component of the Beijing-Kunming Corridor, one of the main corridors of the national "Eight Vertical and Eight Horizontal" high-speed railway network. Once completed and opened to traffic, the travel time from Chongqing to Kunming will be shortened from the original 5 hours to 2 hours, which will greatly promote high-quality regional economic development and effectively advance rural revitalization and ethnic unity and progress.