埋入源多道面波分析(MASW)中最小偏移距的估计方法  

Nearest offset design for Multichannel Analysis of Surface Waves(MASW) method with buried source excitations

作　　者：刘康[1,2,3,4] 戴靠山[4,5] 许强 翁渝峰[4] 黄李观[4] 赵逍 游庆瑜 LIU Kang;DAI KaoShan;XU Qiang;WENG YuFeng;HUANG LiGuan;ZHAO Xiao;YOU QingYu(Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutes of Earth Science, Chinese Academy of Sciences, Beijing 100029, China;University of Chinese Academy of Sciences, Beijing 100049, China;State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院油气资源研究重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,北京100049 [4]同济大学土木工程防灾国家重点实验室,上海200092 [5]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059

出　　处：《地球物理学报》2018年第6期2421-2432,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金(U1710111); 成都理工大学地质灾害防治与地质环境保护国家重点实验室开放基金(SKLGP2016K006); 上海市国际科技合作项目(16510711300)联合资助

摘　　要：多道面波分析(MASW)法是一种被广泛使用的浅层地震勘探方法.为解决埋入源近场效应对MASW法应用的影响,本文分析了埋入源产生的Rayleigh波传播机制,探讨了MASW法的排列参数对地震记录的影响,提出了确定最小偏移距的经验公式.通过对实际地质模型的有限元模拟,验证了经验公式的合理性.在以经验公式为指导的野外实测中,利用多种方法提取了相对可靠的频散曲线,采用基阶和高阶面波联合反演,所得的一维速度结构与钻孔资料具有很强的相关性,表明本文发展的最小偏移距估计方法具有一定的实际应用价值.Multichannel Analysis of Surface Waves（MASW）method,has found wide applications in shallow exploration for civil and earthquake engineering.One interesting problem associated withthe application of MASW method is how to select the geophone′s nearest offset.The nearest offset is a key parameter that controls the near-field effect,so it affects the dispersion image′s resolution and the inversion results.This paper studies the propagation of Rayleigh waves generated by buried source and develops an empirical equation for the nearest offset estimation based on the Ray theory,which is verified by numerical simulation.A case study at a site close to a subway line is implemented with the guidance of the proposed empirical equation.The one dimensional shear velocity structure,obtained by ajoint inversion of both fundamental and higher modes,shows a clear correlation with the given geologic features.Therefore,the proposed nearest offset estimation method is recommended in the real-world application of MASW method for cases as Rayleigh waves are generated by a buried source.

关 键 词：多道面波勘探 RAYLEIGH波 埋入源 最小偏移距 射线理论 

分 类 号：P631[天文地球—地质矿产勘探]