Effects of seabed flexibility on the seismic responses of offshore piles considering water-pile-soil interaction

The dynamic responses of water-pile-soil system subjected to horizontal earthquakes considering seabed flexibility on hydrodynamic pressures is investigated in this paper. The hydrodynamic pressure on the pile is obtained by the inviscid compressible fluid theory and the absorption of pressure waves due to the seabed flexibility is modeled by using a reflection coefficient which is frequency independent. The horizontal resistance of the soil is obtained based on the viscoelastic dynamic continuum model. Based on the analytical solution for the seismic responses of the free-field soil, the numerical model for the seismic response of the pile is developed by using the finite element method. Parametric studies are further conducted to illustrate the influence of seabed flexibility on the seismic responses of the pile.