Assessment and Propagation of Noise from Conventional and Quiet Pile Drivers

摘要

Noise levels, spectra and waveform shapes of noise from commercial pile drivers were studied. Noise propagation characteristics and the effects of interposition of a barrier were also examined. The analog data were analyzed digitally to examine pressure waveforms and sound pressure level time histories. Noise reduction techniques employed by each manufacturer are described. Equivalent sound levels 20 to 40 dB (A) are generated by the extensively treated piling rigs as compared with the conventional untreated piling rigs. The overall A weighted equivalent sound levels from pile drivers attenuate with a rate of approximately 7.1 dB (A) per doubling of distance from the source. The effect of barriers upon the reduction of piling noise can be reasonably predicted by the use of simple barrier theories. The unobstructed propagation of impulsive noise over real ground surfaces does not appear to have significant effect in changing the character of the impulsive sound. This observation also applies when the sound from such a source propagates over the low barriers.