Effect of Ice on the Heat-Moisture Regime of Soil Foundation of Gas Pipeline

Operation of long-haul trunk pipelines in permafrost areas has shown that they undergo various negative processes, such as sweating, thermokarst, ice formation, etc. Especially in the mountainous areas, crossing the water barrier, in the wintertime ground is covered with ice. The interaction of pipelines with ice is not well researched. The purpose of this work is the numerical simulation of the heat-moisture regime of the soil base of the gas pipeline during the formation of ice. A mathematical model of heat and moisture transfer taking into account the actual process of freezing-thawing of the pore solution of soil is given. For mathematical modelling, a numerical experiment was performed to restore the heat flow of the icy valley using the method of solving boundary inverse heat conduction problems. As a result of a numerical experiment, it was established that the permafrost groundwater increases the average annual temperature of the soil around the pipeline and has a warming effect. During long-term operation of a gas pipeline with a positive temperature, the temperature of the soil base rises, but the thawing halo around the gas pipeline is small, which depends on the depth and thickness of pipe insulation.