A Novel Two‐Dimensional Axisymmetric Thermo‐Hydro‐Mechanical Coupled Model for Subsea Pipeline‐Soil System Considering Imperfect Interfacial Thermal Contact

ABSTRACT Subsea oil pipelines typically operate under high‐temperature and high‐pressure conditions, where imperfect contact at the pipeline‐soil interface hinders heat transfer. However, existing calculation models neglect the effect of interfacial thermal resistance, leading to inaccurate predictions of pipeline‐soil interactions. This article establishes a two‐dimensional (2D) axisymmetric thermo‐hydro‐mechanical (THM) coupling model for deeply buried subsea pipeline and saturated soil based on single‐phase thermoelastic theory and saturated porous thermoelastic theory, respectively. The general thermal contact model is introduced to characterize the interfacial thermal resistance effects. A semi‐analytical solution for pipeline‐soil interaction is obtained through Laplace transforms and separation of variables. The differences in THM coupled response between pipeline‐soil system under various thermal contact models are examined, and the influence of thermal expansion coefficients on pipeline‐soil interaction is parametrically investigated under the general thermal contact model. The results indicate that the general thermal contact model can describes the THM coupling characteristics of the pipeline‐soil interaction more realistically; the interfacial thermal resistance effect causes a significant radial temperature gradient at the interface within the pipeline‐soil system, slightly increases the axial temperature difference inside the pipeline, affects the influence of thermal expansion coefficient on the pipeline‐soil interaction, and reduces the deformation compatibility; the influence of the interfacial thermal resistance effect becomes more pronounced as thermal expansion coefficient increases. The deformation compatibility of the pipeline‐soil system decreases as the thermal resistance coefficient and partition thermal contact coefficient increase.