Modelling of pipeline under differential frost heave considering post-peak reduction of uplift resistance in frozen soil

Abstract

The interaction between buried chilled gas pipelines and the surrounding frozen soil subjected to differential frost heave displacements has been investigated. A simplified semi-analytical solution has been developed considering the post-peak reduction of uplift resistance in frozen soil as observed in laboratory tests. The nonlinear stress–strain behaviour of the pipeline at large strains has been incorporated in the analysis using an equivalent bending stiffness. The predicted results agree well with our finite element analysis and also with numerical predictions available in the literature, hence the simple semi-analytical solution can be considered as an alternative to numerical techniques. A parametric study has been carried out to identify the influence of key factors that can modify the uplift resistance in frozen soil. Among them, the residual uplift resistance has been found to be the important parameter for the development of stresses and strains in the pipeline.Key words: pipeline, frost heave, discontinuous permafrost, semi-analytical solution, uplift resistance, frozen soil.