二维大地电磁静位移估算及其在隧道勘探中的应用  

The Estimation of Two Dimensional Magnetotelluric Static Shift and Its Application in the Tunnel Exploration

作　　者：王绪本[1] 周军[1] 李海蓉[1] 李坚[2] 苟定才[2] 

机构地区：[1]成都理工大学,成都610059 [2]中铁二院工程集团有限责任公司,成都610031

出　　处：《铁道工程学报》2014年第8期20-26,43,共8页Journal of Railway Engineering Society

基　　金：国家自然科学基金项目(41274078);国家863高技术研究发展计划(2014AA06A612)

摘　　要：研究目的:在长大隧道的音频大地电磁勘探中,如何客观地识别与处理静态位移引起的虚假电性异常是主要技术难题之一。考虑到二维结构中阻抗相位不受静态位移影响的特点,提出了基于阻抗相位的静态位移因子估算方法,以期可以对静态位移量进行更为客观地估算。在此基础上,开展了静态位移因子在二维反演中的应用研究,以确保反演模型的电性结构更为合理。研究结论:(1)与目前其他静态校正方法相比,以阻抗相位为基础估算得到的静位移因子客观真实、人为随意性较小;(2)使用位移因子对异常区实测曲线进行平移,根据平移曲线的一维反演结果可以为二维反演构建较合理的初始模型;(3)对原始数据进行二维反演,既能有效地消除静态效应对反演模型深部结构的影响,也能在反演中获得正确的浅部电性结构;(4)模型验算以及工程实例表明:本文提出的静态位移因子估算算法及其在反演中的应用方法可以有效地压制二维大地电磁静态效应。Research purposes： In the audio magnetotelluric exploration of large railway tunnel, it is one of technical problems that how to objectively recognize and deal with the false electrical abnormality caused by static shift. Considering the response characteristics that two - dimensional magnetotelluric impedance phase is not affected by the static shift, we put forward an estimation method of static shift based on impedance phase, hoping that this can more objectively estimate the static shift parameter. On this basis, static shift parameter is used in the two dimensional inversion, in order to ensure that the electrical structure of the inversion model is more reasonable. Research conclusions：Compared with the other static shift correction method, the static shift parameter that is estimated based on impedance phase can be close to the true value, artificial arbitrariness is smaller. Use shift parameter for translation of anomaly measured curve, according to the one - dimensional inversion curve results after the translation construct a reasonable initial model for the two - dimensional inversion. On the basis, we do two - dimensional inversion for the original data, which not only can effectively eliminate the influence of static shift on the deep structure of inversion model, but also can get the right shallow electrical structure in the inversion. The model calculation and engineering cases show that the estimation algorithm of the static shift and its application method in the inversion, caneffectively removal the two -dimensional magnetotelluric static shift.

关 键 词：大地电磁测深 静态位移 阻抗相位 二维反演 长大隧道 

分 类 号：U212.2[交通运输工程—道路与铁道工程]