Abstract:

High-intensity wave loads in marine environments can induce stress changes in the seabed soil surrounding piles, affecting the bearing capacity of the embedded sections of single piles. Consequently, the wave-induced dynamic response of the seabed significantly affects the horizontal impedance of single piles in marine environments. This study models ocean waves as harmonic waves of specific frequencies and analyzes the seabed soil’s dynamic response under linear wave loads using a fully dynamic (FD) model based on the soil’s porous elastic assumption. The seabed soil’s dynamic response results in a horizontal external load on the pile section. An analytical solution for calculating the horizontal impedance of a single pile is proposed using the Winkler foundation and Euler beam models to simulate the pile-soil system, and the transfer matrix method to address soil stratification. This formula comprehensively considers the impact of wave-induced seabed dynamic response on the pile’s horizontal impedance. The validity of this method is verified through comparison with previous experimental results. Finally, the primary factors affecting the horizontal impedance of single piles under seabed dynamic response conditions are analyzed. The results show that the horizontal dynamic impedance of single piles in marine environments is related to wave intensity, pile diameter, and seabed soil parameters. The impact of seabed dynamic response on the horizontal impedance of single piles is mainly characterized by a wave in stiffness K_h and an increase in damping C_h within a certain frequency range. Outside this range, the pile impedance is similar to result obtained without considering the seabed dynamic response. Additionally, the impact frequency range expands with increasing pile diameter, pile-soil stiffness ratio and permeability coefficient.

Key words: single pile foundation, horizontal impedance, wave load, seabed dynamic response, Winkler foundation