结合青藏铁路昆仑山隧道，分析了多年冻土地区隧道冻胀产生的原因，提出了“一次衬砌+防水隔热层+二次衬砌”的新型防冻胀结构型式。通过对昆仑山隧道现场气温、地温和洞内围岩温度、冻胀力、初期支护和二次衬砌应力等一系列的测试表明，该结构安全可靠，昆仑山隧道的建成使多年冻土隧道的修建技术取得了长足的进步.

Taking Kunlunshan tunnel on QinghaiTibet railway as example, the author analyzes the reasons for the frost heaving of the tunnels in permafrost regions and recommends a new kind of antifrostheaving structure, which is composed of primary reinforcement, waterproofing and thermalinsulating layer and secondary lining. The measurement of the atmospheric temperature and ground temperature at the site of Kunlunshan tunnel and the measurement of the temperature of the surrounding rock mass inside the tunnel, the frostheaving forces and the stresses of the primary reinforcement and the secondary lining show that this kind of lining structure is safe and reliable. The successful construction of Kunlunshan tunnel indicates that the construction technology of permafrost tunnels has achieved great progress.