[Explanation] On July 30, after nearly 4 years of construction in the alpine region, the Qixingfeng Tunnel, the northernmost high-speed railway under construction in China, was successfully completed. It marks that the construction of the most difficult node of the Mujia high-speed railway has been fully overcome, laying the foundation for the completion of the track laying of the whole line.
【Explanation】Mujia High-speed Railway Qixingfeng Tunnel is located in Huanan County, Jiamusi City, Heilongjiang Province and Jixian County, Shuangyashan City, passing through Qixingfeng National Forest Park and Qixingfeng Provincial Geopark. The total length of the tunnel is 10,291 meters, and the maximum buried depth is 423.5 meters. The geological structure is complex, the rock formations are highly weathered, and the water inflow is extremely large. It is a first-level risk tunnel. It is a difficult and controlled project on the whole line, and it is also the northernmost high-speed railway under construction in China and Heilongjiang The longest tunnel under construction in the province.
[Concurrent] Zhou Huanhuan, Chief Engineer of Mujia High-speed Railway Qixingfeng Project, China Railway First Bureau
The entire tunnel is located in the Wanda mountain range in the northeast, the stratum is relatively old, and the lithology of the entire tunnel is basically metamorphic rock. During the construction process, we fully combined the means of advanced geological forecasting. When the dangerous rock ahead is detected, we then carry out planned excavation and tunneling. When encountering special circumstances, we also follow the rock change. I changed the concept to fully strengthen the excavation and support measures.
[Explanation] Mujia High-speed Railway is located in the high-cold area. The frost-free period of the year is only 140 days. The average winter temperature is -19℃, and the lowest temperature is -35℃. The long-term low temperature and severe cold bring great challenges to the construction of high-speed rail. The construction unit adopts the factory-based production organization model, and after the steel structure of the tunnel construction is completed, they are uniformly distributed to the operation site, which not only ensures the quality of the project, but also greatly improves the construction efficiency.
[Concurrent] Zhou Huanhuan, Chief Engineer of Mujia High-speed Railway Qixingfeng Project, China Railway First Bureau
There are two main aspects of thermal insulation in winter construction. The first aspect is the mixing station outside the cave. We have a fully enclosed insulation for the mixing station to ensure that the concrete exit temperature can meet the requirements. The second aspect is Two curtains are hung at the entrance of the tunnel, and a stove is placed between the curtains, and hot air cannons are used to ensure the construction temperature inside the tunnel.
[Explanation] It is understood that since the start of construction of the tunnel in November 2016, the builders have broken through 8 geological faults and passed through 18 geophysical prospecting high-risk abnormal areas. The construction unit has widely used new equipment and new technologies such as electromagnetic welding of waterproof panels, anti-cavitation devices for tunnel linings, and successively overcome sudden geological disasters such as crushing and deformation of surrounding rocks, development of cracks, and mud and water inrush, and applied BIM tunnel full-section image scanning Technology, “replicating the real scene” of the construction site to ensure that the tunnel penetration task is completed on time and with high quality.
[Concurrent] Zhou Huanhuan, Chief Engineer of Mujia High-speed Railway Qixingfeng Project, China Railway First Bureau
During the tunnel construction process, we fully integrated the BIM technology to make the entire tunnel's supporting system and drainage system perfectly reproduced in three dimensions. Through this method, all the construction personnel, especially the frontline workers, can fully To understand what our tunnel looks like, what the tunnel should look like, and what standards should be made.
[Explanation] Mujia High-speed Railway is an important part of China's high-speed railway network. 141 bridges and 34 tunnels are designed for the entire line, with a total length of 371.6 kilometers. After the completion of the Mujia high-speed railway, it will effectively expand the radiation range of the northeast high-speed railway network and create a new engine for regional economic development.
Reporter Wei Lai reports from Shuangyashan in Heilongjiang
Editor in charge: [Ji Xiang]