On December 28, the Guangming Tunnel, a key project on the newly built Chengdu-Dazhou-Wanzhou High-Speed Railway, was successfully holed through. At present, the entire line's tunnel engineering design comprises 136 tunnels, of which 132 have been holed through, accounting for nearly 97%; the entire line has entered the construction stage of ballastless track beds, station buildings, and the four-electric (communication, signaling, power supply, and electrification) systems.

      The Guangming Tunnel of the Chengdu-Dazhou-Wanzhou High-Speed Railway is located within Kaijiang County of Sichuan Province and Kaizhou District of Chongqing Municipality, situated precisely at a key node connecting Sichuan and Chongqing. With a total length of more than 8 kilometers and a design speed of 350 kilometers per hour, it is a single-tube double-track low-gas tunnel. The rock mass throughout the tunnel is fractured, and the surrounding rock stability is poor. In addition, the tunnel presents high-risk factors such as mud and water inrushes and excessive gas and harmful gases, resulting in a complex working environment, great construction difficulty, and high safety risks.

      To cope with harmful gases such as gas and hydrogen sulfide contained in the coal seams, the project management team used explosives specially designed for coal mines with a higher safety grade and digital detonators for blasting, while enhancing ventilation, monitoring, and other measures inside the tunnel to safeguard tunnel construction safety in multiple dimensions and in an all-round manner. In addition, a variety of intelligent equipment was adopted during construction to improve construction efficiency, significantly reduce labor intensity, and ensure that the project's construction safety and quality objectives are fully achieved at an excellent level.

      More than 600 builders were divided into four working faces for simultaneous construction, successfully overcoming many difficulties such as mud and water inrushes and excessive gas and harmful gases in the tunnel, and opening up this key connection point. At present, construction of the Chengdu-Dazhou-Wanzhou High-Speed Railway is proceeding smoothly. The subgrade engineering for the entire line has completed about 46 million cubic meters, accounting for 98.87%; the bridge pile foundations, pile caps, and pier shafts have all been completed; three of the four rotating bridges along the entire line have been completed; and the entire line is now entering the construction stage of ballastless track beds, station buildings, and the four-electric systems.