Particle Motion from Offshore Impact Piling Including Pile–Soil Linear Contact Slip

Abstract

Besides the underwater sound generated by offshore pile-driving, particle motion near the seabed can be detected by many marine species, raising concerns about ecological effects. Both particle motion and underwater noise may influence the behavior and health of organisms sensitive to these disturbances. These potential impacts highlight the importance of predictive models that represent the interactions between the pile, the soil, and the seawater. This case study examines how pile–soil contact during impact pile-driving may affect particle motions in the seawater column and the seabed. In reality, the pile–soil interaction in the process of pile-driving is nonlinear. However, a linear equivalent representation allows one to investigate, to a reasonable extent, the effects on the acoustoelastic waves generated in the soil–water domain. Linear springs and dashpots are therefore introduced at the pile–soil interface, allowing relative motions to develop between the soil and the pile, that is, linear contact slip is introduced. A case study is conducted to evaluate the implications of pile slip on vibroacoustic behavior, with a particular focus on the resulting particle motion trajectories in the vicinity of the seabed. The findings of this study are presented alongside the potential perceptibility and sensitivity of vibrations by marine species.