引言多年冻土一般分布在我国高纬度和高海拔区域,前者分布在东北地区,后者分布在西部高山高原及东部一些较高山地,冻土是一种对温度极为敏感的土体介质,含有丰富的地下冰。因此,冻土具有流变性,其长期强度远低于瞬时强度特征。正由于这些特征,在冻土区修筑工程构筑物就必须面临两大危险:冻胀和融沉。我国的青藏铁路就有一段路段需要通过冻土层。如果对冻土处理不当,往往会引起建筑物的变形,开裂甚至破坏,造成很大的经济 Introduction Permafrost is generally distributed in high latitudes and high altitudes in China. The former is located in the northeast region, the latter is located in the western alpine plateau and some higher mountains in the east. The permafrost is a temperature-sensitive soil medium containing Rich underground ice. Therefore, the permafrost is rheological, its long-term strength is much lower than the instantaneous strength characteristics. It is because of these characteristics that two major dangers must be confronted in the construction of structures in permafrost: frost heaving and thawing. There is a section of Qinghai-Tibet Railway in China that needs to pass through the permafrost layer. If the frozen soil is not properly handled, it will often cause the building to deform, crack or even destroy, resulting in a large economy