Study on correlation between microtremor characteristics and site characteristics in typical laterite areas based on HHT
A systematic microtremor measurement was conducted on typical laterite sites.The empirical mode decomposition(EMD)in Hilbert Huang transform(HHT)was used to decompose the effective microtremor signals from the measurement signals.Fast Fourier transform(FFT)and Hilbert transform were used to ge-nerate power spectral curves and Hilbert marginal spectral curves of the effective microtremor signal to deter-mine the predominant period of the site,and then to explore methods for determining site characteristic param-eters that are different from the direct Fourier methods and H/V spectral ratio methods.The effective micro-tremor signal of the target site is the fourth intrinsic mode function(IMF4)derived from EMD.The predomi-nant period of microtremor obtained by FFT and Hilbert transformation on the IMF4 of each measurement point ranges from 0.20～0.36s in the horizontal direction and from 0.23～0.39s in the vertical direction.Such results indicate that the determination of site classification and division of geotechnical types through microtremor measurement based on HHT is highly consistent and correlated with the drilling results of the site.
microtremorsite characteristicsHHTpredominant periodlaterite areas
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