摘要
可控源音频大地电磁法(Controlled Source Audio-Frequency Magnetotelluric,CSAMT)采用人工发射电磁波到地下,然后在远场接收的方式,具有探测深度大、抗干扰能力强、不易受到高阻屏蔽、横向纵向分辨率高等优点被广泛应用到工程地质勘察、石油和天然气勘探、固体矿产资源勘查以及深部构造断裂调查研究当中。本次研究通过云南滇中引水工程其中一段隧洞工程区对应用CSAMT进行断裂构造探测的实例研究,说明该方法在此类工程应用中的效果及优势。首先在介绍CSAMT工作原理的基础上,着重对活动断裂探测中的野外工作方法、室内数据处理以及数据解释方面进行了说明,尤其是地形影响的抑制。然后根据反演得到的二维视电阻率剖面图与野外地质构造相结合进行综合地质解译,在剖面上划分出断层、岩性界面等地质要素,与地表实际调查发现的断层和地质界线具有良好对应关系,说明CSAMT在断裂构造探测的应用效果较好。本次研究成果为后续的钻孔勘探、隧道布设及开挖施工提供前瞻性基础资料。
Controlled source audio magnetotelluric method(CSAMT)mainly relies on the artificial transmitting technology of electromagnetic waves into the ground and retrieved in the far-field area.Because of its advantages of deep-probing depth,anti-interference ability,less susceptibility to high resistance shield,high resolution along both horizontal and vertical direction,it is widely used in engineering geological exploration,exploration of petroleum or mineral resources research and deep structural faults investigation.This paper introduces a case study applying CSAMT to deep structural faults detection in one tunnel engineering area of Yunnan Dianzhong water diversion project,and illustrates its effectiveness and advantages in such engineering applications.Based on the working principle of CSAMT,this article elaborates the field working methods,indoor data processing and data interpretation in active fault detection,especially the suppression of terrain effects.Integrating the inversion of the two-dimensional apparent resistivity profile and the geological structures in the field,a comprehensive geological interpretation is realized and the significant geological elements such as faults and lithological interfaces on the profile are identified.Finally,the comparison between these interpretations and the on-ground investigating faults and geological boundaries shows favorable correspondence,and demonstrates an excellent application of the CSAMT on the detection of fault structures,which provides forward-looking basic data for subsequent drilling exploration,tunnel layout and excavation construction.
作者
罗文行
房艳国
周云
吴海斌
翁文林
付兴伟
Luo Wenxing;Fang Yanguo;Zhou Yun;Wu Haibin;Weng Wenlin;Fu Xingwei(Changjiang Survey,Planning,Design and Research Co.,Ltd.,Wuhan Hubei 430010,China;China Three Gorges Corporation Co.,Ltd.,Beijing 100038,China)
出处
《工程地球物理学报》
2020年第6期759-767,共9页
Chinese Journal of Engineering Geophysics
基金
国家重点研发计划(编号:2016YFC0401803)。
