Response of offshore large-diameter pipe piles in layered poroelastic soil to lateral dynamic loading

Abstract

The analytical solution for the lateral dynamic response of offshore large-diameter pipe piles embedded in seawater and layered saturated seabed soil is proposed. The hydrodynamic pressures of the outer and inner seawater are derived based on the inviscid compressible assumption of fluid, and the dynamic soil resistances of the outer and inner layered saturated seabed soil are derived based on Biot's poroelastic theory. The analytical expressions of the lateral dynamic response of the pile are obtained by using the transfer matrix method, and the dynamic characteristics of the lateral response of offshore pipe piles are parametrically investigated. It is concluded from the analysis results that the outer and inner hydrodynamic pressures significantly affect the natural frequency of the pile–water–soil system. Additionally, employing a homogeneous soil model with the same average modulus to represent the layered seabed soil can lead to significantly inaccurate estimations of the natural frequency and pile-head displacement of offshore pipe piles.