PERMAFROST OIL PIPELINE SOIL TEMPERATURE FIELD AND STRESS-STRAIN STATE ANALYSIS ERROR ESTIMATION

Abstract

The effects of some natural and artificial factors on the thermal interaction between a pipeline and permafrost soil has been studied. A mathematical model describing the soil temperature profile, thawed soil subsidence and pipeline elevation has been proposed. A temperature profile of the soil around the pipeline has been determined through solving the heat conductivity equation. The analysis accounts for the thermal interaction between the pipeline and permafrost soil; soil surface heat exchange; and porous moisture phase transformation heat exchange. For displacement and stress-strain analysis a pipeline has been represented as an elastic endless beam exposed to complex loads. The thermal and mechanical pipeline to soil interaction analysis accuracy has been estimated as the surrounding soil temperature field, the thaw halo border, and the pipeline stress-strain state is determined. The error is estimated by analyzing the data obtained analytically and through experiments. The obtained accuracy is sufficient to apply the proposed model for long-term stress-strain state analysis of a pipeline in permafrost. The model can identify vulnerable permafrost pipeline sections, and forecast the scope of work for each pipeline segment.