Particle motion from submerged impact pile driving

Abstract

The deployment of floating offshore wind turbines requires the installation of anchoring systems in deep-water environments, where pile driving operations may be performed using fully submerged impact hammers. While underwater noise from offshore pile driving has been widely studied, most existing approaches assume impacts occurring in air and may not entirely capture these emerging installation configurations. Furthermore, current assessment frameworks are primarily based on pressure-related acoustic metrics and do not explicitly account for particle motion. This study investigates the vibro-acoustic response of a driven pile under submerged impact conditions, with particular focus on particle motion in both the water column and the seabed. A physics-based modelling approach is adopted to analyse the coupled pile–soil–fluid system, capturing both the radiated acoustic field in the water and the vibration field transmitted through the seabed. The response is described in terms of particle velocity, enabling a consistent representation across both media. The results provide insight into the mechanisms governing energy transmission into the seabed, supporting a more comprehensive assessment of environmental effects in deep-water pile installation.