Recently, great efforts have been dedicated to the phenomenon of wave-induced seabed instability in the vicinity of marine structures. The evaluation of the wave-induced soil response (including pore pressure, effective stresses and soil displacements) has been recognized as an important factor in the analysis of the instability of the seabed. This paper proposes a finite difference model in a curvilinear coordinate system to investigate the wave-induced soil response in the vicinity of a buried pipeline. The potential of the wave-induced seabed instability is studied as a function of geometry (buried depth and the diameter of a pipe) as well as the degree of saturation.
A marine pipeline is a commonly-used offshore installation for dispose of industrial and municipal waste water into the sea, for cooling water in nuclear power plants, and for the transportation of gas and crude oil from offshore platforms. The wave-induced soil response in the vicinity of a buried pipeline has been recognized by geotechnical engineers as one of the important factors that must be considered in the analysis of pipeline stability. Design of marine pipelines for their instability is a rather complicated problem. An inadequate design can cause flotation of the pipeline, leading subsequently to costly failure and environmental catastrophes (Clukey et at., 1989). Thus, it is beneficial for engineering practice to improve knowledge on wave-soil-pipeline interaction. When ocean waves propagate in shallow water, they exert dynamic pressures on the seafloor. The fluctuations of wave pressure will further induce effective stresses and pore pressures in a sedimentary seabed. When the pore pressure becomes excessive in comparison with changes in effective stresses, the seabed may be moved in the either vertical (liquefaction) or horizontal directions (shear failure), and then lead to an instability of the seabed (Rahman, 1997).
