Assignment of initial parameters and boundary conditions for modeling thermal state of underground pipelines in a zone of progression of island permafrost soils

Abstract

Relevance. Determined by the importance of predictive modeling of thermal state of pipeline transport facilities located in the permafrost zone. Prediction of geocryological effects is possible through computer simulation of heat and mechanical interactions between a pipeline and a soil medium. Such simulators use data on climatic and geocryological conditions and processes, as well as the information about design and process-dependent parameters of the pipeline, data on its spatial positioning. The presence of various factors influencing heat and mass transfer, as well as the complexity of their numerical simulation, can lead to incorrect design decisions. Such decisions in their turn are always associated with a loss of mechanical safety in an underground pipeline operation. To eliminate this design problem, it is necessary to correctly take into account and adopt the most relevant methods for modeling processes and soil characteristics. Aim. To conduct an analytical comparison of the results of thermal engineering calculations of one section of the route with insular permafrost in order to identify the influence of the model initial parameters on the stress-strain state of the pipeline. Methods. Analyzing the results of engineering surveys for the object of study, conducting a number of numerical calculations, and factorial comparison of the calculation results. Results. At the first stage, the authors have selected the route section of the underground pipeline corresponding to the purpose of the research, the factors influencing the results of thermal modeling. These factors will be considered in this study. At the second stage, the authors carried out modeling of 30 calculation models of one route section with a different set of input data. A factorial comparison of the effect of heat engineering calculation on the results was carried out. At the last stage, the authors carried out the strength calculations of all options for the selected section of the pipeline route as a resulting indicator of the influence of factors.

Keywords

• gas pipeline
• engineering-geological conditions
• numerical modeling
• insular permafrost
• underground pipeline
• permafrost soils