Wave‐Induced Forces on Buried Pipelines

Abstract

Wave‐induced pressures are an important design consideration for oil and natural gas pipelines buried in the marine environment. Realistic problems are three‐dimensional in nature and involve waves approaching the buried pipeline at oblique angles and special pipeline geometries. For fluid flow in a sandy soil where liquefaction does not occur and fluid acceleration terms are negligible, Darcy's law can be used. Assuming that the soil structure and fluid are incompressible, results will show the wave‐induced pressure in the domain being governed by the Laplace equation with associated boundary conditions on the domain boundaries. The pressure distribution on the pipeline is obtained using the boundary integral equation method (BIEM). The BIEM is economical because the computations are performed only on the two‐dimensional surface boundaries of the solution domain rather than throughout the entire three‐dimensional domain. The first problem analyzed is the two‐dimensional case where the pipeline is parallel to the wave crests. The numerical solutions show good agreement with finite element and analytical solutions. For waves approaching at oblique angles, the periodic pressure distribution on the pipelines is obtained. Finally, solutions are obtained for soils of different properties. Future work is proposed in order to apply the techniques to more general problems.