Effect of mechanical properties of permafrost soil on the stress state of a pipeline during settlements

Abstract

A brief analysis of methods for calculating the stress-strain state of a pipeline laid in permafrost conditions is given. The analysis of models of interaction of the pipeline with the soil during longitudinal and transverse displacements is given. The tasks of the interaction of the pipeline with the soil are set to determine the place of formation of plastic zones during thawing of the pipeline section. A problem with a symmetrical formulation and a problem in which a semi-infinite pipeline is determined are considered. The places of the highest values of the stress-strain state of a pipeline with a diameter of 1020 mm when two soil massifs moved relative to each other due to soil thawing were determined. The results are shown as a change in the dependence of longitudinal stresses on the amount of displacement. The distribution of stresses in the dangerous section of the pipeline is shown, the most dangerous sections are determined. The process of formation of a zone with plastic deformation of the pipeline wall metal is shown. The main mechanical characteristics of the soil that affect the stress-strain state of the pipeline are determined, an analysis is made of the influence of the mechanical characteristics of the soil on the maximum equivalent stress of the pipeline. Keywords: permafrost; pipeline; soil; mechanical properties; numerical methods; strain; stress.