基于相位差法和多重滤波法结合的瑞雷面波频散曲线研究  

Study of Rayleigh Wave Dispersion Curves Based on the Combinationof Phase Difference Method and Multiple Filtering Method

作　　者：谌强 熊章强[1,2] 张大洲[1,2] Chen Qiang;Xiong Zhangqiang;Zhang Dazhou(School of Geosciences and Info-Physics,Central South University,Changsha Hunan 410083,China;Key Laboratory of Nonferrous Metal Formation Prediction and Geological Environment Monitoring,Ministry of Education,Central South University,Changsha Hunan 410083,China)

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083 [2]中南大学有色金属成矿预测与地质环境监测教育部重点实验室,湖南长沙410083

出　　处：《工程地球物理学报》2021年第6期856-866,共11页Chinese Journal of Engineering Geophysics

基　　金：国家自然科学基金(编号:41274123)。

摘　　要：多道面波分析法(MASW)在垂向上有较高的探测精度,但在横向上由于多道叠加效应而分辨率较低,无法较好地探测如溶洞、孤石等横向速度变化大的地质异常体。面波谱分析法(SASW)和多重滤波法通过两道数据计算频散曲线,虽然有较高的横向分辨率,但由于不同模式或不同频率的面波信号在计算其相位和时间时容易相互干扰而使得计算得到的速度值不准确,因此考虑将相位差法和多重滤波法相结合以提高频散曲线的准确性,从而提高横向分辨率。本文首先通过利用相位差法和多重滤波法分别计算得到对应的相速度值,然后创建一个F-V谱将两者结果进行叠加,最后再提取频散曲线。采用该方法对两层模型数据提取频散曲线并与理论值进行对比分析,结果表明所提取的频散曲线具有较高的准确性和可靠性。通过对斜坡模型数值模拟的波场数据提取频散曲线并转换为拟二维剖面,其结果证实了两道数据提取频散曲线具有较高的横向分辨率。进一步通过实例表明利用该方法提取频散曲线具有良好的实际应用效果。The multi-channel surface wave analysis method has high detection accuracy in the vertical direction,but low resolution in the lateral direction due to the superposition effect of multiple channels,so it cannot well detect geological anomalies such as karst cavesand boulders with large lateral velocity changes.The SASW and the multi-filtering method calculate the dispersion curve by using two channels of data.Although they have high lateral resolution,the velocity values obtained are inaccurate because the phase and time of surface wave signals with different modes or frequencies are easy to interfere with each other.A combination of the phase difference method and the multiple filtering method is therefore considered to improve the accuracy of the dispersion curves and hence the lateral resolution.In this paper,the corresponding phase velocity values are first calculated by using the phase difference method and the multiple filtering method,then an F-V spectrum is created to superimpose the two results,and finally the dispersion curves are extracted.Using this method,the dispersion curves of two-layer modelare extracted and compared with theoretical values.The results show that the extracted dispersion curves are highly accurate and reliable.By extracting the dispersion curves from wavefield data of numerical simulation of slope model and converting them into a proposed 2D profile,the results prove that the dispersion curves extracted from the two data channels have high lateral resolution.It is further demonstrated by example that this method has a practical application effect in extracting dispersion curves.

关 键 词：瑞雷面波 多重滤波 相位差 频散曲线 

分 类 号：P631.4[天文地球—地质矿产勘探]