高原融区和多年冻土过渡路段涵洞地基试验研究

In-situ Experimental Study on Railway Culvert in Thaw and Permafrost Transition Regions of Tibetan Plateau

运用现场测试方法,对青藏铁路两座拼装式涵洞的基础变形、地基土地温及洞口气温的测试结果进行分析,研究多年冻土区涵洞工程对冻土地温状况、冻融过程、冻土上限变化的影响以及涵洞基础的冻融变形特征。结果表明:多年冻土地区修建涵洞工程后,气温对地温的影响增大,致使涵洞下原多年冻土上限附近地温波动明显,地温年变化深度增大;由于场地冻土条件及地温场沿涵身的变化,涵洞基础变形沿涵身表现出明显的不均匀性。

With the field test method, this paper analyzes the results of the foundation deformation, ground temperature and air temperature of two culverts on Qinghai-Tibet railway. It also studies the influence of culvert to the ground temperature state, the thaw and frost process, the change of permafrost table as well as the characteristics of frost heave and thaw subsidence. The analytical results show that ground temperature at the permafrost table waves violently after the culverts are established. It is obviously different from that under natural ground. At the same time, the deformation of frozen soils including frost heave and thaw subsidence is asymmetrical along its axes because of the changes of soil conditions.