Numerical Modelling of Sound Radiation from Marine Pile Driving over Elastic Seabeds

Abstract

This work investigates the underwater sound emission of marine pile driving over elastic seabeds. The finite element method is used to model sound pressure in the near field of an axisymmetric pile and environment model, where the seabed is modelled as both fluid (fluid sand) and elastic (sand, calcarenite) materials. The presented results show that the inclusion of shear in the seabed has a marked effect on the characteristics of the radiated acoustic field in the water column, even for seabed materials which have a low shear speed. In particular, the secondary structural waves reflected from the pile ends in the elastic seabed model emit significantly less acoustic energy compared to the fluid seabed models. Scholte waves also can be observed to propagate along the fluid-solid interface in the elastic seabed models.