Numerical evaluation of pile vibration and noise emission during offshore pile driving

When offshore structures like converter platforms or wind turbines are founded by pile driving, high noise level are emitted into the water. In this paper a numerical model will be presented and validated which is able to effectively predict the noise emission during pile driving under offshore conditions. It combines a Finite Element Method in the near field of the pile with a Parabolic Equation technique to compute the pressure spectrum, sound exposure and peak level in a certain distance of the pile. The results will be compared to measurements performed during two full scale offshore tests. Furthermore, a procedure for computing the acoustic properties of the sediment as a function of the frequency, depth and density is presented. This allows to represent the layered sediment at the construction site within the numerical methods.