Liquefaction analysis on a seabed under combined wave and current loadings

Abstract

Marine structures and the seabed are subjected to all kinds of marine environmental loadings for a long time, especially wave and current loadings. Most previous investigations of the dynamic response of marine structures and the seabed have only considered the influence of wave loading, but the important influence of current was ignored. In recent years, some scholars have studied the dynamic response of the seabed under combined wave and current loadings, but relatively few studies deal with liquefaction analysis under the combined wave and current loadings. On the basis of the poro-elastic theory by Biot and combined two-dimensional non-linear progressive wave and uniform current theory, an accumulated excess pore-water pressure calculation model considering the effect of instantaneous pore pressure on accumulated pore-water pressure is proposed in this paper. The seabed response of instantaneous pore pressure and accumulated pore-water pressure under the combined wave and current loadings are calculated through this model. The effects of the time, current velocity, consolidation coefficient, the relative density and water depth on excess pore pressure are discussed in detail; furthermore the stability of the seabed is evaluated through the liquefaction analysis.