Project introduction: the tunnel is in Hekashan area on a denudational landform at middle or high mountains. It is about 3,700~3,960m above the sea level and lasts 2,315m long. In the area, landform changes significantly and sharply. Overall, the middle part is higher and both sides lower. The project site is in cold temperate arid steppe type affected by plateau continental climate with the freezing period from October to April of the next year. The lowest temperature in Heka Town in January is -29℃, monthly average temperature at -9.9℃, average temperature above 0℃ from November to March of the next year, July enjoying the extremely high temperature, with average temperature of 16.1℃; maximal frozen earth depth at 2.11m; according to empirical data about the temperature changes along with altitude in Qinghai-Tibetan Plateau, the project site suffers the average monthly temperature of -13. 5℃ in the coldest months. 

The project was completed by the end of 2008 and adopted FL FLOLIC FOAM Freezing-thawing Resistant System for Tunnels in Extremely Cold Areas; FLOLIC FOAM insulating thickness: 45 mm.