Author(s): Dong-Zi Pan; Cun-Hong Pan; Li-Zhong Wang
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Keywords: No Keywords
Abstract: Waves propagating over the ocean surface exert dynamic pressure fluctuations on the sea floor, and these fluctuations further generate an excess pore pressure within the soil skeleton. Field evidence and calculations strongly indicate that this excess pore pressure results in soft-sediment deformation due to liquefaction. The liquefaction can generally be categorized naturally into two types. The momentary liquefaction is due to the oscillatory excess pore pressure and is accompanied by attenuation of the amplitude and phase lag. Whilst the progressive liquefaction is caused by an increase in a residual excess pore pressure and a decrease in the effective stress. The other type of seabed liquefaction is described in this paper, which named as superficial liquefaction because continuous fluidization near the surface of seabed is observed. A semi-analytical solution for the onset of superficial liquefaction and the final depth of liquefaction front subjected to a given wave loading are derived in this paper. The presented solution is based on the equilibrium of forces on a single grain and takes into account physical effects of the pore pressure gradient. Comparison between numerical results and model test is also proposed.
Year: 2009