Influence of Groundwater in the Base of the Gas Pipeline During the Formation of Aufeis

Abstract

Pipelines with a large length in permafrost areas pass through various water passages. In winter, due to various types of waters – underground, river, and lake (often ice has mixed nutrition) – we observe the formation of aufeis. When they repeatedly pour out onto the surface and layer by layer freezing, plane-convex ice bodies are formed – aufeis. The heat and mass transfer interaction of a gas pipeline with a frozen ground base is considered during the filtration of permafrost groundwaters. Numerical modelling was carried out taking into account the real thawing process – freezing of the pore solution in the temperature spectrum at various temperature regimes of filtration of permafrost groundwater. As a result of a numerical experiment, it was established that aufeis formation occurs in the second half of winter and has a warming effect. In the first half of the summer period, intensive thawing of aufeis is observed, and the dynamics of the depth of seasonal thawing occurs with some delay, but at the beginning of the winter period, it is restored, as in ordinary soil. Long-term seasonal filtration of groundwater with a natural temperature of the environment has a warming effect on the temperature regime of frozen rocks. Warming and increased water saturation of the frozen soil base are accompanied by negative seasonal permafrost processes.