Construction difficulties in neijiang-kunming railway

The middle section of neijiang-kunming railway, especially the 23.5‰ continuous long ramp of 85km from Daguan to Zhaotong North, is unprecedented in the construction of Chengdu Railway Bureau because of its complicated terrain and harsh construction environment. This section is located in the dangerous mountain from Sichuan Basin to Yunnan-Guizhou Plateau, in which Daguan to Tianliangzi is only over 30 kilometers, with an altitude difference of 600-700 meters. Through the foggy area where the basin climate changes to plateau climate all year round, foggy weather accounts for more than 350 days in a year. Most lines are located in long tunnels and steep slopes. One side of the line is a steep mountain wall, and the other side is a cliff abyss hundreds of meters deep. The bridge is high and steep, and even some stations are located on the bridge or in the tunnel. The construction conditions are extremely difficult and the construction environment is extremely bad.

Experts agree that it is not an exaggeration to call neijiang-kunming railway "geological encyclopedia". There are frequent geological disasters here, and the most harmful ones are rock piles, soft soil, karst, landslides, dangerous rock falls and mudslides. Because of the rock pile, the geological drilling work of Neikun line is 1 times higher than that of ordinary railway. In order to deal with rock piles, the builder's best strategy is to "hide". If it is really impossible to hide, anchor pile toe pre-reinforcement and other technologies will be adopted, and the rock pile at 9 1 along the line will be in a stable state. Soft soil is also "unique" distributed on the slope of Neikun Line, and the design of Lizigou Station alone has been changed for 30 times. Zhuga Tunnel is 5194m long, which is the longest gas tunnel in China. The Iron 18 Bureau, which is responsible for the construction of the entrance section, mobilized 40 million yuan worth of mechanical equipment and organized technical forces to tackle key scientific problems in view of the characteristics of high gas, large water inflow and weak geology, and successfully solved the ventilation problem of the high gas tunnel. Railway Administration 18 undertook the construction of Gao Qiao-Ba Du Nanpanjiang Bridge Team, the world's first V-shaped support on Nanning-Kunming Railway, and was responsible for the construction of Lizigou Bridge in the southern section of Nanning-Kunming Railway. The total length of the bridge is1023.5m, and its128m long span is 529. The 6-meter cantilever continuous beam is the first of the four bridges on Neikun Line. Huatupo Bridge, located in the south section of Neikun Line, has the highest pier 1 10 meter.