寒区浅埋输油管线冻胀安全性分析

Frozen-Heaving of Frost-Soil Bed of Shallow-Buried Oil-Pipeline in Cold-Region

针对寒区输油管所在区域特殊的地理气候环境,适当选取输油管工程中涉及的物理参数和数学物理模型,尽可能真实地模拟地面和输油管区域的边界条件,建立寒区浅埋输油管线耦合冻结过程的有限元分析模型;在此基础上采用现有有限元分析软件(ANSYS)分析地面温度周期变化情况下,地面以下土体内温度场分布和土体的冻结情况,确定最大冻结深度与冻结线随时间的变化;最后进行热应力分析,确定了土体季节性冻、胀融化过程中油管壁的应力随时间变化情况以及油管的竖向位移,以此计算结果来评价寒区输油管线的使用安全性。

According to the particularity of cold-region for its geographical and climatic environments where the oil-pipeline was laid, the author adopted suitably physical parameters and mathematical-physical models involved in the oil-pipeline system, to simulate the boundary conditions of ground surfaces and the region where oil-pipeline is located, and constructed finite element （FE） analysis models of the coupled freezing process of shallow buried oil-pipeline in cold region. By using commercial FE software（ANSYS） ,this paper analyzed the temprature and freezing distribution of the frost soil, under the situation of status seasonal and annual periodical change of ground-surface temperature, the time-history curve of the maximum depth of freezing and freezing ridge-line distribution were figured out. Finally, the thermal-stress was analyzed to make sure how the stress of oil-pipeline wall change during the soil frost and seasonal melting process, and the vertical displacement of the pipeline was also studied. Accordingly, this paper estimated the safety of shallow-buried oilpipeline system of frost soil bed.