Simplified approach for analyzing thermal buckling of pipeline based on nonlinear Pasternak foundation model

Abstract

The modeling of the nonlinear pipeline-soil interaction under multiple stress conditions is the most dominant factor affecting the precise prediction of the thermal buckling of submarine pipelines at high temperatures. In this study, a nonlinear Pasternak foundation model (NPFM) is introduced to simulate the soil-pipeline interaction when the thermal buckling occurs. This model accounts for the nonlinear but continuous deformation of the seabed. To solve the proposed mathematical problems, an effective Newton's iterative computational program, combined with the finite difference method, is developed to analyze the nonlinear responses of the pipeline. Restricting the outcomes of the iteration to the permissible tolerance range enhances the precision of the computational analysis in this study. The reliability and applicability of this method are verified by comparing it with published results and predictions from six elastic foundation models based on different subgrade reaction moduli. The study further analyzes the influence of pipeline design parameters, buried depth, and backfill material on pipeline buckling behavior. The results indicate that increasing the outer diameter and buried depth significantly inhibits thermal buckling, while pipeline wall thickness and backfill material have a lesser impact.