Stress prediction equation for buried pipelines subjected to internal loading and cold wave-induced soil temperature

Buried water pipelines are critical infrastructure lifelines whose vulnerability to failure under complex thermo-mechanical loading during extreme cold waves poses a significant threat to public safety and urban resilience. As climate change alters temperature extremes, infrastructure designed under historical conditions may face heightened risk. However, current analytical methods for estimating pipe stress neglect thermo-mechanical coupling, limiting their applicability under the increasing frequency of extreme temperature events driven by global climate change. To address this gap, this study develops a novel closed-form predictive equation that explicitly incorporates thermo-mechanical coupling effects through an extensive three-dimensional finite element (FE) analysis program. A validated thermo-mechanical FE model served as the basis for 2,187 numerical simulations examining the effects of nine dimensionless variables governing the pipe-soil-thermal interaction, including geometric ratios, material properties, and loading conditions. The resulting equation, derived via nonlinear regression and dimensional analysis, predicts maximum stress with high accuracy, achieving R 2 values of 0.9556 and 0.9569 on training and test data, respectively. Independent verification using 53 parametric cases with a control variable approach confirms the model’s robustness, with over 90% of predictions falling within a 10% error band and typical errors of 6–8%. A global sensitivity analysis using Spearman’s rank correlation coefficient identified the pipe’s coefficient of thermal expansion as the most influential parameter, accounting for approximately 20% of the stress response. The proposed equation provides a practical and physically grounded tool for assessing buried water pipe performance under cold wave conditions, offering significant potential for enhancing the resilience of urban water infrastructure.