How beamforming can be combined with other measurements to bring information about the noise generation

Two full-scale experiment sessions were performed to study the noise generation during vibratory pile driving of double Z sheet piles. A beamforming system was used in order to localize the noise generation and to separate it from the ambient noise sources. The obtained pictures show that the sheet pile can be the main sound source. Furthermore, additional information about the mechanisms involved in the noise generation, as impacts with the safety device or with the neighbouring sheet piles are analysed By using a thermographic camera, it was possible to prove the heat generation and thus to confirm impact occurrences. If the sheet pile configuration avoids such impacts, the sound power level decreases drastically and the nature of the sound is different: structure-borne sound is transmitted into the air by the interaction with the soil and free vibrator radiation.