Dynamic Behavior of Buried PE Pipelines under Stochastic Track Loads: A Vehicle–Road–Pipe Coupled Modeling Approach

Buried polyethylene (PE) pipelines are extensively employed in urban municipal infrastructure and are frequently exposed to complex dynamic environments caused by vehicular loads. However, existing research often overlooks the coupled interactions between road structure and stochastic vehicle excitations, thereby limiting the accuracy and reliability of pipeline safety assessments. To address this gap, this study systematically investigates the dynamic response behavior of buried PE pipelines under stochastic vehicular loading, considering the effects of road structure and key load parameters. A coupled vehicle–road–pipeline finite-element model was established using ADAMS and ABAQUS, in which dynamic wheel loads induced by uneven road surfaces were accurately applied to the pipeline system via a user-defined subroutine. The results reveal that the uncertainty of vehicular loads significantly influences the stress distribution and dynamic response characteristics of buried pipelines. With increasing load magnitude and vehicle speed, stress concentrations at the pipeline crown and invert intensify, exhibiting a pronounced nonlinear dynamic amplification effect. Comparative analysis indicates that rigid pavement structures more effectively mitigate stress transmission and concentration risks than flexible or unpaved roads. Based on these findings, engineering recommendations are proposed: in heavy-load or high-frequency traffic areas, thick-walled PE pipes with low standard dimension ratios should be prioritized; shallow-buried pipelines should be reinforced using high-stiffness backfill or localized structural enhancements. This study underscores the critical role of road–load coupling effects in determining the mechanical performance of buried PE pipelines and provides important engineering guidance for improving the accuracy of urban pipeline safety evaluations.