Analysis on Noise Characteristics of Underwater Impact Piling in Cross-sea Bridge Projects and Discussion on Control Measures

Abstract

Underwater pile driving is a common operational method in engineering projects such as offshore bridges and offshore wind farms, and the impact of underwater noise on the marine ecological environment has attracted increasing attention. This paper analyzes the characteristics of underwater noise from impact pile driving based on on-site measured data during the construction of the Dong-Wu-Yang cross-sea bridge. Impact pile driving can create an intense, impulsive, and sharp sound, which has a peak sound pressure level more than 240dB re1μPa at 1 m. The sound source frequency is mainly concentrated in the 10 to 1000Hz frequency band, which has a strong impact on offshore cetaceans and sound-sensitive fish. Various measures to control underwater piling noise and adopting noise reduction technology were discussed, including selecting low-noise equipment, changing piling parameters, bubble curtain, and cofferdam, etc., and the feasibility of which were analyzed according to the construction environment.

Keywords

• underwater piling noise
• noise characteristics
• noise control
• offshore bridges projects