Model Studies of Wave-Seabed Interactions

Several factors such as the wave characteristics, the seabed type, the sediment size, and the porosity characteristics influence the transient porewater pressure response below the mudline due to wave-seabed interaction. Experiments were conducted in a soil-wave tank in which the pressure variation profile inside a porous bed of sand was measured for different wave types. The measured pressures were correlated with simple theories based on wave energy dissipation in permeable seabed. Tests were conducted in which the combination of wave and soil conditions caused soil liquefaction and instability. These results were extrapolated to predict the potential conditions that may cause seabed instability in the Hibernia area of the Newfoundland Grand Banks. The experimental assembly, the results and correlations, and the limitations are discussed in this paper.