Keyword: «complex pipeline deformations»

As a result of seasonal thawing and freezing of the surrounding soil, an underground pipeline, laid in the permafrost area, undergoes vertical displacement changes twice a year. Complex deformations occur in some sections, manifesting as multiple arches transitioning into one another without intervals. This article proposes a methodology for assessing the stresses that occur in the pipeline in such sec-tions. An equation describing the vertical position of the underground pipeline, depending on the weight of the soil above and the reactions of the soil below, has been obtained. There is no need to explicitly specify longitudinal forces in the equation, which greatly simplifies field work in data collection. The soil reactions are determined by using the gradient descent method in solving the equation.

Trunk pipelines laid on the territory of Yakutia are operated in the area of permafrost. A particular hazard in the floodplain area for underground pipelines is moisture migration during freezing and thawing of frozen soils, from which the pipeline changes position twice a year. The article provides an assessment of mechanical stresses from deformations created by frost beams. Mathematical description and selection of underground pipeline model, as well as determination of soil reaction are proposed, obtained position functions by point horizontal and vertical measurements and evaluation of stresses in underground pipeline are shown.