Wave-Induced Seabed Pore Pressure and Forces on a Buried Pipeline Under Cross-Shore Profile Evolution

In view of the complex seabed response and pipeline force characteristics induced by wave loading and long-term cross-shore profile evolution on shoreward submarine pipelines, this study investigates the coupled effects of profile evolution, burial depth, and pipeline angle on the surrounding seabed and resulting wave-induced forces. Physical model experiments were conducted in a wave flume under irregular wave conditions. A controlled variable design was adopted, dividing the experiments into five main groups and 17 subgroups based on the pipeline angle, initial burial depth, and seabed topography at different evolution stages. Pore pressure around the pipeline and wave height were measured synchronously, and seabed topography was scanned using a laser system. The results show that increasing the initial burial depth reduces both pore pressure and forces on the pipeline. Under cross-shore profile evolution, pore pressure and forces in sedimentation zones are lower and decrease further with continued evolution, whereas the opposite trend is observed in erosion zones. Changes in pipeline angle induce an asymmetric pore pressure distribution around the pipeline, with the resultant force first decreasing and then increasing. The direction of the resultant force shows greater rotation amplitude in sedimentation zones while, in erosion zones, the direction remains more concentrated. In sedimentation zones, pore pressure decreases and force changes are relatively gradual; in erosion zones, pore pressure increases and force changes are more pronounced. Overall, the variations in force direction and magnitude exhibit distinct characteristics depending on the zone type. These findings provide a scientific basis for the rational design of shoreward pipelines, enabling stability and safety optimization through integration with cross-shore profile evolution patterns, reducing engineering risks, and enhancing the economic viability and reliability of nearshore pipeline projects.