Computational & Technology Resources
an online resource for computational,
engineering & technology publications
Civil-Comp Proceedings
ISSN 1759-3433
CCP: 89
Edited by: M. Papadrakakis and B.H.V. Topping
Paper 173

Non-Linear Wave-Induced Pore Pressure Accumulations in a Porous Seabed

D.-S. Jeng

Division of Civil Engineering, School of Engineering, Physics and Mathematics, University of Dundee, United Kingdom

Full Bibliographic Reference for this paper
D.-S. Jeng, "Non-Linear Wave-Induced Pore Pressure Accumulations in a Porous Seabed", in M. Papadrakakis, B.H.V. Topping, (Editors), "Proceedings of the Sixth International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 173, 2008. doi:10.4203/ccp.89.173
Keywords: residual pore pressure, consolidation, marine sediment, wave nonlinearity.

The evaluation of the wave-induced soil response in marine sediments is particularly important for coastal engineers involved in the design of the foundations of many marine installations, e.g., offshore mono-piles, breakwaters, pipelines and platforms etc. Predictions of the wave-induced excess pore pressure is a key procedure in the analysis of seabed instability such as liquefaction and scour. Therefore, it is necessary to have a better understanding of the mechanism of the wave-induced pore pressure in marine sediments.

In general, two mechanisms for wave-induced pore pressure have been observed in field measurements and laboratory experiments [1]. The first mechanism results from the transient or oscillatory excess pore pressure and is accompanied by attenuation of the amplitude and phase lag in the pore pressure changes [2]. The second mechanism is termed the residual pore pressure, which is the build-up of excess pore pressure caused by contraction of the soil under the action of cyclic loading [3]. Recently, a series of analytical approximations for the wave-induced accumulated pore pressure in marine sediments have been proposed by the author [5]. Both cases of infinite and finite soil layers were considered in the models. A simplified universal formula was proposed for the case of an infinite seabed [4]. However, all these approximations were limited to linear regular wave loadings, although they should be non-linear waves in natural environments.

In this paper, the models developed by the author [4,5] are further extended to non-linear wave loadings. The new model is verified with experimental data [6], and provide a better prediction of pore pressure accumulation than the previous solution with linear wave theory. The parametric study concludes that the influence of wave non-linearity increases as wave steepness (H/L) and the residual parameter (alpha) increases. However, an opposite trend is found for another residual parameter (beta).

H. Nago, S. Maeno, T. Matsumoto and Y. Hacgiman, "Liquefaction and densification of loosely deposited sand bed under water pressure variation", Proceedings of the 3rd International Offshore and Polar Engineering Conference, Singapore, 578-584, 1993.
T. Yamamoto, H. Koning, H. Sellmejjer, E. van Hijum, "On the response of a poroelastic bed to water waves", Journal of Fluid Mechanics, 87, 193-206, 1978. doi:10.1017/S0022112078003006
H.B. Seed and M.S. Rahman, "Wave-induced pore pressure in relation to ocean floor stability of cohesionless soil", Marine Geotechnology, 3(2), 123-150, 1978. doi:10.1080/10641197809379798
D.-S. Jeng and B.R. Seymour, "A simplified analytical approximation for pore-water pressure build-up in a porous seabed", Journal of the Waterway, Port, Coastal and Ocean Engineering, ASCE, 133(4), 309-331, 2007. doi:10.1061/(ASCE)0733-950X(2007)133:4(309)
D.-S. Jeng, B.R. Seymour and J. Li, "A new approximation for pore pressure accumulation in marine sediment due to water waves", International Journal for Numerical and Analytical Methods in Geomechanics, 31(1), 53-69, 2007. doi:10.1002/nag.547
E.C. Clukey, F.H. Kulhawy, P.L.-F. Liu, "Laboratory and field investigation of wave-sediment interaction", Joseph H.Defrees Hydraulics Laboratory, School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, 1983.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £95 +P&P)