Analytical approach for lateral vibration analysis of offshore pipe piles in multi-layered poroelastic soils

Abstract

This study presents an analytical solution for the lateral vibration of offshore piles embedded in multi-layered poroelastic soils, taking into account the effect of variations in soil plug height. The pipe pile is divided into four sections to analyze its interaction with different media. The governing equations for each section are solved separately, and the pile impedance is derived considering the continuity conditions between adjacent sections. Upon comparing the proposed solution with the outcomes of previous studies, its effectiveness is validated. The findings demonstrate that deeper water conditions diminish natural frequencies and augment resonance amplitudes of offshore pipe piles. The influence of dynamic water–pile interaction on the lateral dynamic response of offshore pile foundations is pronounced and must be taken into account when analyzing these responses. Notably, the modulus of the upper soil layer emerges as a pivotal determinant in the lateral dynamic behavior of the pile. The modulus of the soil plug within the pile is observed to have a minimal impact on its lateral dynamic response. Furthermore, the findings reveal that overlooking variations in soil plug height can lead to inaccurate assessments of the lateral impedance of offshore pipe piles.