Lateral dynamic response of an offshore hollow pile in multilayered poroelastic soils considering effect of vertical load

Abstract

This paper investigates the lateral dynamic response of an offshore hollow pile within multilayered poroelastic soils, considering dynamic water-pile interaction (DWPI) and effect of vertical load. Initially, Using the method of separation of variables, the governing equations for inviscid compressible fluid and saturated poroelastic medium are solved to derive analytical expressions for the hydrodynamic force and soil resistance acting on the offshore hollow pile. Subsequently, by considering the continuity conditions at the soil–pile interface and the water-pile interface, the governing equations for the free, submerged, and embedded parts of the pile are solved, resulting in the solution for the lateral vibration of the offshore hollow pile. The lateral impedance of the offshore hollow pile is then determined using the transfer matrix method. Through parametric analysis, this study examines the influence of pile diameter, pile wall thickness, water depth, DWPI, vertical load, soil modulus, and soil permeability on the lateral dynamic response of offshore hollow piles. The findings emphasize that neglecting DWPI leads to an underestimation of the first-order resonance amplitude of the offshore hollow pile and an overestimation of its natural frequency, with the influence of vertical load on pile impedance amplified with increased water depth.