Operation Problems of the Cold Condensate Pipeline in Heaving Soils and Arctic Climate

The chapter is devoted to the problem of a condensate pipeline operation with negative product temperature, arctic climate, and discontinuous permafrost and heaving soils. The laying of pipelines in permafrost soils requires special solutions to stabilize the temperature regime of the soil and protect the pipelines from uncontrolled subsidence. For the considered pipeline, the project provides the cooling of gas condensate to temperatures of about −3 °C. This method stabilized permafrost soils and ensured designed spatial position. However, the pipeline transports the product to the south and crosses the zones of continuous, discontinuous, and sporadic distribution of permafrost soils. The project has no thermal insulation in the areas of thawed soils. As a result, the pipeline freezes the soil around it. On heaving soils, it leads to significant vertical displacements and inadmissible change of the stress–strain state. On one of these sections, the stresses exceeded the tensile strength of the steel and caused a depressurization. To explain the causes of depressurization, a mathematical model of the stress–strain state of the pipeline on heaving soils was used, taking into account the climatic conditions and ensemble of interrelated processes: heat and mass transfer in the soils, deformation of the soils, and deformation of the pipeline. Sufficient accuracy of the model was confirmed. Methods for solving the problem of frost heaving for this pipeline were proposed.