摘要
对典型红土场地开展系统的地脉动测试,基于希尔伯特-黄变换(Hilbert-Huang transform,HHT)中的经验模态分解(empirical mode decomposition,EMD)从测试信号中分解出场地有效地脉动信号,对其进行快速傅里叶变换(fast Fourier transform,FFT)和Hilbert变换,产生功率谱曲线和Hilbert边际谱曲线,以确定场地卓越周期,进而探索与直接傅氏法和H/V谱比法不同的场地特征参数判别方法.目标场地的有效地脉动信号为 EMD 分解后的第 4 个本征模态函数(4th intrinsic mode function,IMF4),对各个测点的IMF4 进行FFT和Hilbert变换,获取的地脉动卓越周期水平向在 0.20～0.36 s,垂直向在 0.23～0.39 s,结果表明,基于HHT的地脉动测试法来确定场地类别、划分场地岩土类型,与场地钻孔分析结果一致性高,关联性强.
Abstract
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.
基金项目
国家自然科学基金(52068002)
江西省"双千计划"项目(DHSQT32022006/JXSQ2020101041)
江西省自然科学基金(20202BABL204064)
NETL
NSTL
万方数据