F—K变换与主动源面波法在南昌市昌东地质调查中的应用  

Application of F—K Transform and Active Source Surface Wave Method in Geological Survey of the East of Nanchang City

作　　者：尹玉茹 黄光南[1] 汤洪志[1] 杨子敬 Yin Yuru;Huang Guangnan;Tang Hongzhi;Yang Zijing(Department of Geophysics,East China University of Science and Technology,Nanchang Jiangxi 330001,China)

机构地区：[1]东华理工大学应用地球物理系,江西南昌330001

出　　处：《工程地球物理学报》2023年第1期82-89,共8页Chinese Journal of Engineering Geophysics

基　　金：国家自然科学基金(编号:42064007,41504095)。

摘　　要：主动源面波勘探被广泛地应用于浅地表地层的速度调查工作,此次南昌城市地质调查利用主动源面波勘探方法,运用于东湖区道路的地下空间探测。为了压制干扰波,优化数据处理结果,获得可靠的地下地层分布情况,利用频率-波数(F—K)滤波方法对地震数据进行处理。F—K滤波方法是根据频率和视速度的内在关系,同时考虑这两方面的影响因素来对数据进行滤波,由于面波的频率较低、视速度也较低,采用F—K滤波器处理原始数据,分离其他干扰波。可以较好地滤除原始数据中的高频电磁干扰波以及反射波获得纯面波数据成分,达到压制相干线性噪声的目的,将后续处理过程中频散曲线拟合的误差值降低到5%以内。随后进行的频散分析和速度反演中得到的面波速度反演结果取得了良好的地质分层效果,可以得到明显的分层结果,由上到下是人工填土低速层,粉质沙土及分选性好的细砂和中砂沉积物于中间层位,底部则为分选性较差的粗砂、沙砾沉积物。该方法在浅地表地层的速度调查中快速、准确地得到了地下空间地层分布情况,取得了良好的应用价值,值得在工程实践中推广使用。Active source surface wave exploration is widely used to investigate the velocity of shallow surface strata.The Nanchang urban geological survey uses the active source surface wave exploration method to explore the underground space of the road in Donghu district.In order to suppress interference waves,optimize data processing results and obtain reliable distribution of underground strata,frequency wave-number(F—K)filtering method is used to process seismic data.Based on the intrinsic relationship between frequency and apparent velocity,the F—K filtering method considers the influencing factors of these two aspects to filter the data.Because of the low frequency of the surface wave and the apparent small velocity,the F—K filter is adopted to process the original data and separate other interference waves,which can better filter out the high-frequency electromagnetic interference waves and reflected waves in the original data to obtain pure surface wave data components,achieving the purpose of suppressing coherent linear noise,and reducing the error value of the intermediate frequency dispersion curve fitting in the subsequent process to less than 5%.The surface wave velocity inversion results obtained in the subsequent dispersion analysis and velocity inversion have achieved good geological stratification results,and obvious advantegeous stratification results.From top to bottom,we find the low-velocity layer of artificial fill,silty sand and well-sorted fine sand and find medium sand sediments in the middle layer,and poorly sorted coarse sand and gravel sediments at the bottom.This method can help obtain the distribution of underground space strata in the velocity survey of shallow surface strata more quickly and accurately,and has achieved good application value,which is worth popularizing in engineering practice.

关 键 词：主动源 面波勘探 频散曲线 横波速度 

分 类 号：P631.4[天文地球—地质矿产勘探] P622[天文地球—地质学]