The National Railway Administration announced on the 22nd the official release of the railway industry engineering construction standard "Code for Design of Railway Tunnels in Cold Regions" (hereinafter referred to as the "Code"), which creates "exclusive design guidelines" tailored for cold-region railway tunnel projects through a standardized, professional, and refined design system.
It is understood that the "Code" establishes a method for classifying frost-resistance protection levels using the average temperature of the coldest month and the annual average temperature as dual control indicators, laying the foundation for precise protection by tunnel classification; it clarifies the anti-freezing protection lengths for tunnel portal drainage and the main structure, building a complete frost-resistance protection system; and it specifies tunnel insulation technical requirements applicable to cold-region railway tunnels, such as concrete and insulation materials, ensuring the safety and stability of tunnel structures.
As China's railway mileage exceeds 165,000 kilometers, cold-region railways are increasingly coming into public view. Cold-region railways generally refer to railways located in areas where the average temperature of the coldest month is below 0°C, or the annual average temperature is below 15°C. China's severe cold regions are mainly distributed in Heilongjiang, Jilin, Liaoning, Inner Mongolia, northern Xinjiang, Qinghai, Tibet, and other places.
The biggest challenge for cold-region railways is the problem of frost heave. This is especially true for cold-region railway tunnels, where freezing and thawing alternate repeatedly, making tunnel walls prone to bulging and cracking, with water seepage and icing occurring in gaps, leading to various defects that affect traffic safety. Doing a good job in tunnel cold protection and frost resistance design is equivalent to putting exclusive cold-proof and warm insulation clothing on cold-region railway tunnels. This step is key to ensuring tunnel structural stability, extending service life, and ensuring traffic safety, and directly determines the construction and operation quality of tunnels.
China has rich experience in the construction and operation of cold-region railways. From the "magical heavenly road" Qinghai-Tibet Railway, to the first high-cold high-speed railway Harbin-Dalian Railway, and to the soon-to-open northernmost high-speed railway Harbin-Yichun High-Speed Railway, cold-region railway tunnels have accumulated rich engineering practice experience in fields such as structural frost resistance and drainage system frost protection, and have achieved multiple advanced scientific research results.