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.