Moisture-heat-stress coupling numerical simulation of buried pipeline in saturated aquifer permafrost area

Through numerical simulation analysis of temperature field, moisture field and strain stress field of the frozen soil layer around the buriedpipeline in the saturated aquifer permafrost area, general patterns for uneven distribution and change of stress and strain of the pipelinecrossing the permafrost area are obtained. Due to heat dissipation of the pipeline, structure and composition of surrounding frozen soillayer are destroyed, soil pore water is reduced and heat storage capacity is less than that of the thawed soil. In addition, heat carried by themoisture heat transfer and mass transfer makes the soil drier. These changes affect soil deformation and stress state. The soil above thepipeline is subject to severe strain and stress changes, and the soil around the pipeline gradually increases strain and reduces stress, prone tothaw collapse. Non-thawy permafrost under the pipeline shall be less than the above melted soils in the strain subject to layered decline andthe stress continuously increases due to soil reinforcement.