Unburied offshore pipeline stability analysis for severe storm condition

The purpose of this paper is to investigate the stability of an unburied offshore pipeline under severe storm condition. Pore pressure accumulation and pipeline movement during cyclic loading caused by waves and currents are numerically investigated. Both drag and lift forces are numerically obtained for 100 years return period storm condition using the Fourier decomposition method. Pipeline movement strongly depends on the seabed characteristics as well as the cyclic loading obtained from severe storm condition. When the stiffness of seabed and the fine grained soil content are large, not only the pipeline movement but also the pore pressure response in seabed beneath the pipeline increases with the number of cycles.