Reliability of pressurised pipelines subjected to longitudinal ground movement

摘要

A methodology was developed to calculate the probabilities of tensile rupture and compressive local buckling for pressurised pipelines that are buried in unstable slopes and subjected to longitudinal loading imposed by the slopes. The limit state functions were established by comparing the tensile and compressive strain demand with the corresponding strain capacities. The strain demand is calculated using an analytical model reported in the literature, which is capable of accounting for the elastic-plastic behaviour of the pipeline and the elastic-perfectly plastic behaviour of the pipe-soil friction. The strain capacities are characterized based on the information available in the literature. The spatial variability of the soil and pipe properties is incorporated in a simplified manner. A numerical example was used to illustrate the proposed methodology and impact of the spatiality variability of the soil and pipe properties on the failure probability. The analysis results suggest that the spatial variability of pipe wall thickness and yield strength tends to increase the failure probability, whereas the spatial variability of the soil ultimate resistance tends to decrease the failure probability.