Wave-induced seabed instability in front of a breakwater

The wave-induced soil response in a porous seabed has become an important factor for the stability of offshore facilities, because many marine structures may have failed due to seabed instability and concomitant subsidence. An analytical solution is presented for the wave-induced soil response under the action of a three-dimensional wave system. Based on this general solution, the mechanism of seabed instability is then investigated. The general solutions for pore pressure and effective stresses are readily reducible to two dimensions for progressive waves, and are compared to theoretical and experimental work available. Some dominant factors affecting the wave-induced seabed instability are discussed; including permeability, seabed thickness and degree of saturation.

[1]  D. Jeng,et al.  Wave-induced soil response in an unsaturated anisotropic seabed of finite thickness , 1994 .

[2]  M. Biot.  General Theory of Three‐Dimensional Consolidation , 1941 .

[3]  Dong-Sheng Jeng,et al.  NON‐LINEAR WAVE‐INDUCED RESPONSE OF POROUS SEABED: A FINITE ELEMENT ANALYSIS , 1997 .

[4]  R. Silvester,et al.  Boundary-layer velocities and mass transport in short-crested waves , 1980, Journal of Fluid Mechanics.

[5]  T. Hasegawa,et al.  Evaluation of Wave-Induced Pore Pressure in Sand Layer by Wave Steepness , 1985 .

[6]  M. S. Rahman.  Wave‐induced instability of seabed: Mechanism and conditions , 1991 .

[7]  Dong-Sheng Jeng.  Wave‐induced liquefaction potential in a cross‐anisotropic seabed , 1996 .

[8]  Standing wave induced pore pressures in a porous seabed , 1995 .

[9]  L. Bjerrum,et al.  Geotechnical problems involved in foundations of structures in the North Sea , 1973 .

[10]  Dong-Sheng Jeng,et al.  Soil response in cross-anisotropic seabed due to standing waves , 1997 .

[11]  J. A. Putnam.  Loss of wave energy due to percolation in a permeable sea bottom , 1949 .

[12]  R. Silvester,et al.  Third-order approximation to short-crested waves , 1979, Journal of Fluid Mechanics.

[13]  A. W. Sam Smith,et al.  Large Breakwater Toe Failures , 1983 .

[14]  Dong-Sheng Jeng,et al.  Wave-induced soil response in a nearly saturated sea-bed of finite thickness , 1996 .

[15]  Shiro Maeno,et al.  Liquefaction And Densification of Loosely Deposited Sand Bed Under Water Pressure Variation , 1993 .

[16]  S. Okusa,et al.  Wave-induced stresses in unsaturated submarine sediments , 1985 .

[17]  Chiang C. Mei,et al.  Wave-induced responses in a fluid-filled poro-elastic solid with a free surface : A boundary layer theory , 1981 .

[18]  Dong-Sheng Jeng,et al.  Short-crested wave-induced soil response in a porous seabed of infinite thickness , 1993 .

[19]  D. V. Griffiths.  Some theoretical observations on conical failure criteria in principal stress space , 1986 .

[20]  Jacob Bear,et al.  Flow through porous media , 1969 .

[21]  Dong-Sheng Jeng,et al.  Oscillatory soil response and liquefaction in an unsaturated layered seabed , 1995 .

[22]  Dong-Sheng Jeng,et al.  Finite element modelling for water waves-soil interaction , 1996 .

[23]  Philip L.-F. Liu.  Damping of Water Waves over Porous Bed , 1973 .

[24]  Behrouz Gatmiri,et al.  A simplified finite element analysis of wave-induced effective stresses and pore pressures in permeable sea beds , 1990 .

[25]  Stephen Thomas.  A finite element model for the analysis of wave induced stresses, displacements and pore pressures in an unsaturated seabed II: Model verification , 1995 .

[26]  Ching-Piao Tsai.  Wave-induced liquefaction potential in a porous seabed in front of a breakwater , 1995 .

[27]  D. V. Griffiths.  Failure Criteria Interpretation Based on Mohr-Coulomb Friction , 1990 .

[28]  Brian R. Seymour,et al.  TRANSIENT SOIL RESPONSE IN A POROUS SEABED WITH VARIABLE PERMEABILITY , 1996 .

[29]  Dong-Sheng Jeng,et al.  Wave-Induced Pore Pressure and Effective Stresses in a Porous Seabed With Variable Permeability , 1997 .