ALGORITHM FOR THE PROCESS OF THAWING-FREEZING SOIL REGULATING AROUND THE GROUND PIPELINE IN PERMAFROST

Abstract

In the design of the main and field pipelines in permafrost areas issues of methods of laying and operating conditions selection of the pipeline need to be solved. Engineering activity leads to the destruction of land cover, which in areas with permafrost contributes to the emergence and development of thaw- ing halo or trenches filled with water with a sharp increase in the sea- sonal thaw depth, activation of thermokarst, thermal erosion and other cryogenic processes. Thawing of permafrost soils causes irreversible waterlogging of the main territory, irreversible environmental damage. The current conditions for the development of these regions do not contribute to the preservation of frozen soils, and they are rapidly degrading. The reliability and durability of the structures are the higher the less disturbed cryogenic natural clay base state. This can be achieved by using ground pipelining method. The design of pipeline systems in these areas is particularly difficult due to the inherent instability of heat transfer and thermodynamic processes occurring in the soil. This article shows that the increase in environmental safety and health at the terrestrial trunk pipeline laying is possible by adjusting the halo thawing and thermal-selection mode pumping oil. Ground pipeline heat transfer problem during summer and winter operation taking into account the regulation halo thawing is solved. Its dimensions depend on the magnitude of the heat flow coming from the pipe into the ground. The algorithm for thermohydraulic pumping mode selection, during which the magnitude of halo thawing stays within acceptable limits dur- ing the entire period of operation is proposed. By controlling the thawing halo around the tube, the hydraulic mode stability is achieved with minimum oscillations of pumping performance and temperature during the annual period of use. The practical value of this work is in the fact that the resulting calcula- tions can be used in formulating and solving various technical and eco- nomic problems, taking into account the requirements of environmental integrity, and the search for optimal solutions in the design of pipelines in permafrost.