More than 70 years ago, news of victory at the Battle of Jiangjunshan thrilled the Red Army during the Long March. On June 2, 2016, news that tunneling at the Jiangjunshan Tunnel on the Chengdu-Guiyang Railway had surpassed 1,000 meters sent employees of the Chengdu-Guiyang Railway Project Department of China Railway 15th Bureau Group of CRCC into cheers, because it marked the end of the most difficult phase of the tunnel's construction and a further acceleration of progress on the entire tunnel.

The Jiangjunshan Tunnel on the Chengdu-Guiyang Railway is being built by China Railway 15th Bureau Group of CRCC. With a total length of 2,032 meters, the project is located about 8 km northwest of the seat of Dafang County, Bijie City, Guizhou Province. The area features denudational and karst-eroded low and medium mountain topography of the Yunnan-Guizhou Plateau, and the alignment crosses a belt-shaped mountain range with well-developed slopes and gullies. The highest mountain peak through which the tunnel passes has an elevation of 1,746 m, and the maximum buried depth of the tunnel is 260 m. The entire tunnel lies on a straight alignment with a single-face upward gradient of 19.3‰.

 

The main adverse geological condition of the tunnel is karst, and some karst caves may contain accumulated water, so water and mud inrush accidents may occur during construction. Its exit section is a low-gas tunnel, and the geological conditions are extremely special with poor stability. How to prevent settlement has been listed as a key focus of scientific and technological research.

According to the on-site construction manager, to ensure construction safety and project quality, the Chengdu-Guiyang Railway Project Department of China Railway 15th Bureau Group has established and improved information systems such as advanced geological forecasting, monitoring and measurement, access control, and personnel positioning, and has continuously carried out scientific and technological research to solve various problems encountered in construction through the power of scientific and technological innovation. In particular, the exit section successfully overcame the technical challenge of settlement and was awarded a green card by the owner.