Security of Shallow-buried Oil-pipeline in the freeze-thaw processes of frost-soil bed in cold-region

According to the particularity of cold-region for its geographical and climatic environments where the oil-pipeline is laid, the author adopts 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, constructing finite element (FE) analysis models of the coupled freezing process of shallow buried oil-pipeline in cold region. By use of commercial FE software(ANSYS), to analyze the distribution of frost soil´ temperature and the status of soil freezing beneath ground, under the situation of ground-surface temperature´s seasonal and annual periodical change, finding out the time-history curves of the maximum depth of freezing and freezing ridge-line distribution changes with time. Finally, it analyzes the thermal-stress, make sure how the oil-pipeline steel wall´s stress change during the soil frost heaving and seasonal melting process and the vertical displacement of the pipeline, and estimating the security of shallow-buried oil-pipeline system in the freeze-thaw processes of frost soil bed.