Study of Low-frequency Vibration Isolation and Attenuation Domain Broadening for Periodic Multilayer Pile Barriers
Multi layer piles with perforated soft layers were proposed for low-frequency rail transit vibrations below 10 Hz,and the influence of soft layer filling rate on bandgap was studied through dispersion curves.Through frequency domain analysis,the influence of the number of pile rows was studied,and a pile row combination method with continuous bandgap center frequency was proposed to broaden the attenuation domain.Finally,the attenuation performance of composite pile arrangement on wide and low frequency vibration was studied through time-domain curves.The results show that reducing the filling rate of the soft layer can effectively reduce the bandgap frequency and easily obtain low-frequency bandgaps below 10 Hz.When the filling rate of the soft layer is greater than 80%,the bandgap frequency decreases rapidly with the decrease of the filling rate of the soft layer.When the filling rate of the soft layer is less than 80%,the bandgap frequency decreases slowly with the decrease of the filling rate of the soft layer.When the central frequency band is continuous,the frequency response curve of the combination of multiple types of pile rows is similar to that of a single type of pile row,which can smoothly broaden the attenuation domain,and the more types of pile foundations,the wider the attenuation domain.The combination of multi layer piles can produce a good barrier effect on wide and low-frequency vibration waves,and the fundamental reason for isolation is that most of the incident waves transform into reflected waves under the local resonance of the piles.
NETL
NSTL
万方数据
