一、引言我国多年冻土主要分布在东北大、小兴安岭,西北部高山及青藏高原等地,总面积约215万平方公里,占全国面积的22.3％,若包括冻结深度大于0.5米的季节冻土在内,则占到68.6％,因而对冻土地区的路基工程的研究是很重要的。东北冻土区为欧亚大陆高纬度冻土区的南部地区,其冻土分布明显地受纬度地带性控制。冻土层的年平均地温自北而南升高,大约纬度每降低1°,气温升高1℃,年平均地温升高0.5℃,冻土厚度由50～100米降至5～20米。西部青藏高原冻土区则是世界中、低纬度地 I. INTRODUCTION The permafrost in our country mainly distributes in northeast big, xiaoxinganling, the northwestern high mountain and the Qinghai-Tibet Plateau, with a total area of ​​about 2.15 million square kilometers, accounting for 22.3% of the national area. If the frozen permafrost , Accounting for 68.6%, so the study of subgrade construction in the permafrost region is very important. The northeast permafrost region is the southern part of the high latitude permafrost region of Eurasia, and its frozen soil distribution is obviously controlled by latitudinal zonality. The annual average ground temperature in permafrost increases from north to south, with the temperature increasing by 1 ° C for every 1 ° decrease in latitude, the annual average ground temperature increases by 0.5 ° C, and the permafrost thickness decreases from 50 to 100 meters to 5 to 20 meters . The western Qinghai-Tibet Plateau permafrost region is the world at low latitudes