Response of Porous Seabed to Nature Loadings: Waves and Currents

• Published in: Journal of engineering mechanics Vol. 138; no. 6; pp. 601 - 613
• Main Authors: Ye, J. H, Jeng, D.-S
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.06.2012
• Subjects: Computational methods in fluid dynamics; Dynamic tests; Dynamics of the ocean (upper and deep oceans); Earth, ocean, space; Exact sciences and technology; External geophysics; Fluid dynamics; Fundamental areas of phenomenology (including applications); Liquefaction; Mathematical analysis; Mathematical models; Oceans; Permeability; Physics; Physics of the oceans; Sand; Sea beds; Solid mechanics; Static elasticity (thermoelasticity...); Structural and continuum mechanics; Surface waves, tides and sea level. Seiches; Technical Papers; ocean currents; Transient response; Biot's theory; Fluid wave; porosity; permeability; hydrodynamics; liquefaction; Multiaxial load; Saturated porous medium; Modeling; Waves; Porous seabed; Combined load; Porous media; sand; ocean floors; Biot theory; Sea floor; Seabed response; porous materials; Currents; ocean waves; Sea surface wave
• ISSN: 0733-9399; 1943-7889
• DOI: 10.1061/(ASCE)EM.1943-7889.0000356

AbstractIn real ocean environments, currents generally exist simultaneously with ocean waves. However, the most previous investigations for the seabed response have only considered wave loading, ignoring currents. In this study, unlike previous studies, currents are included in the model of seabed response with waves, based on Biot’s poroelastic dynamic theory (u-p approximation). Numerical results reveal that the consideration of currents has significant effect on the seabed response. The opposing current is beneficial to prevent liquefaction, while the following current would worsen the stability of the seabed. The parametric studies indicate that the wave period, water depth, saturation, soil permeability, and thickness of the seabed significantly affect the seabed response under combined loading of waves and currents. The maximum relative difference of the pore pressure between the cases with currents (velocity is -2  m/s) and without currents (pcurrent-pnocurrent)/p0 can reach up to 25% in both coarse and fine sand. The analysis of transient liquefaction in the fine sand seabed indicates that the maximum liquefaction depth increases with the following currents, but it decreases with the opposing current.