Chencong Liao

An Analytical Approximation for Dynamic Soil Response of a Porous Seabed due to Combined Wave and Current Loading

ABSTRACT Liao, C.C.; Jeng, D.-S., and Zhang, L.L., 2015. An analytical approximation for dynamic soil response of a porous seabed due to combined wave and current loading. This paper presents a new analytical approximation for wave (current)–induced dynamic soil response. In this study, unlike in previous research projects, full dynamic soil behaviour was considered. The nonlinear waves propagating over an infinite seabed with uniform current were investigated, and the new analytical solution was validated with the previous field observations and laboratory experiments. The effects of currents and wave nonlinearity were examined based on the proposed analytical solution. Finally, a parametric study was carried out to examine the influence of the wave and seabed characteristics on the seabed response. As the numerical examples demonstrated, the effects of currents on the seabed response are significant only in the top region of the seabed (comprising approximately 10% of the wavelength). Based on parametric study, it is concluded that currents with third-order wave loading and full dynamic soil behaviour cannot always be ignored in the estimation of the wave-induced seabed responses, especially for almost-saturated soil, long-wave periods, and shallow water. A significant difference was also observed in the maximum liquefaction depth between the full dynamic and the consolidation models.

On the soil response of a coastal sandy slope subjected to tsunami-like solitary wave

This study proposes a two-dimensional coupled approach to examine dynamic response of a sloping beach due to tsunami-like solitary wave. Wave motion is governed by Reynolds-averaged Navier–Stokes (RANS) equations, while the beach response is described with the poro-elastoplastic theory. The wave module and beach module are strongly integrated, resulting in a profound investigation of the solitary wave-induced soil response. Validation against the experimental demonstrates the applicability of the present approach. Results show that the excess pore water pressure ratio (EPWPR) is significant in the shallow soil. Distribution of EPWPR along the soil depth direction shows a decreasing trend. In addition, the principal axes of soil element on the shoreline rotated considerably under the solitary wave loading. When wave draws down from the slope, both shear stress and mean effective stress decrease compared with the run-up process. For engineering practice, special attention is given to the effect of permeability and coast slope on the soil response subjected to tsunami-like solitary waves.