西藏双湖某输电线路沿线多年冻土特征分析

Analysis of Permafrost Characteristics Along a Power Transmission Line in Shuanghu Area of Tibet

藏北高原的双湖地区平均海拔超过5000 m,该地区分布有岛状中纬度高海拔多年冻土,由于区内工程建设少,气候条件恶劣,对该地区多年冻土研究极少。通过大量现场调查、钻探、室内试验等研究表明:该区域多年冻土常分布于丘间凹地及平原地势较低处,岩芯中可见凝冰,冻土含冰量与地形、地下水、地表植被有一定关系。同时该地区多年冻土上限一般在2.0~2.8 m,冻土总含水率最高可达到58.2%,冻土工程特征与引起的地质灾害对工程建设具有很大的危害。因此,在工程建设过程中应合理优化选址、选取合理的基础形式、并配合必要的工程措施确保工程安全。

The Shuanghu area in the northern Tibetan plateau has an average elevation of more than 5000 m,and there are island-like middle-latitude and high-altitude permafrost in this area.Due to the lack of engineering construction and harsh climatic conditions in the region,there are few researches on permafrost in this region.Through a large number of field investigations,drilling,laboratory tests,it is shown that the permafrost in this region is usually distributed in the hilly depression and the lower part of the plain,and frozen ice can be seen in the core.And the upper limit of permafrost in this area is 2.0 m to 2.8 m,the total moisture content of permafrost soil reaches 58.2%at the highest,the characteristics of permafrost engineering and the geological disasters caused by it have great harm to the construction of engineering.Therefore,it is important to rationally optimize the selection of location in the process of engineering construction,and cooperate with necessary measures to ensure the stability of engineering.