Hydrodynamic Modeling of Pipe-Soil Interaction in Subsea Pipelines: Improving Design Methods for Enhanced Performance and Sustainability

The interactions between subsea pipelines and the seabed generate complex vibratory responses that can compromise structural integrity, yet these interactions remain difficult to characterize with sufficient fidelity for design purposes. This study examines a numerical workflow for incorporating hydrodynamic forces and displacement-dependent pipe-soil interaction into the finite element analysis of a nominally 400 m subsea pipeline. The hydrodynamic formulation includes irregular wave kinematics, directional spreading, current effects, and force corrections related to pipeline movement, while the geotechnical representation uses prescribed pipe-soil contact and lateral resistance relationships. The workflow links local resistance characterization with the global structural response and investigates the sensitivity of calculated lateral displacement to applied stabilization weight and seabed strength assumptions. This approach enables computationally efficient structural analysis without sacrificing the fidelity needed to assess whole-system performance, directly addressing the central modeling challenge posed by the pipe-soil interface. Over a 100-year simulated service life, the maximum lateral displacement recorded across the 400 m pipeline reached 5.43 m, while displacement peaked at approximately 3.98 m under a chain weight of 18.37 kg. These results demonstrate the model’s sensitivity to key design parameters governing pipeline stability. The analysis provides an implementation-based case study for assessing the consequences of alternative seabed-resistance assumptions rather than establishing a new soil constitutive model or an independently validated through-life design procedure, and it provides a robust foundation for future subsea pipeline engineering practices.