大地电磁探测技术在旭龙水电站隐蔽构造勘察中的应用  

Study on application of AMT in geophysical exploration of hidden geological structure in Xulong Hydropower Station

作　　者：郭聪 徐涛 陈江平 GUO Cong;XU Tao;CHEN Jiangping(Changjiang Geophysical Exploration&Testing Co.,Ltd.,Wuhan 430010,China;National Dam Safety Engineering Technology Research Center,Wuhan 430010,China)

机构地区：[1]长江地球物理探测(武汉)有限公司,湖北武汉430010 [2]国家大坝安全工程技术研究中心,湖北武汉430010

出　　处：《水利水电快报》2024年第5期36-42,共7页Express Water Resources & Hydropower Information

摘　　要：旭龙水电站前期工程勘察中面临坝库区高陡边坡、滑坡体及超厚覆盖层等复杂地质条件,准确查明该区域的隐蔽构造、裂缝、断层及覆盖层厚度十分关键。引入新型大地电磁测深探测系统,并基于优化改进二维快速松弛反演(RRI)算法,得到了收敛快、曲线平滑的大地电磁测深剖面,提取了丰富的深部地层信息。结果表明:采用低频磁棒、改进的RRI反演算法,有效数据频带延伸到1~0.1 Hz,有效探测深度近1000 m。该技术在超厚覆盖层及深部构造探测中获得了较好的应用效果,克服了旭龙水电站前期勘察技术难点,可为新型大地电磁系统在类似工程的应用提供参考。Xulong Hydropower Station is faced with complex geological conditions such as high and steep slopes,landslides and ultra-thick overburden in the dam and reservoir area,and it is very critical to accurately identify the hidden structures,cracks,faults and thickness of the overburden in the area.A new Audio-frequency Magnetotelluric method was introduced.By improving the algorithm of two-dimensional Rapid Relax Inversion(RRI),the AMT apparent resistivity profile with fast convergence and smooth curve was obtained,which contained information of deep formation.The results showed that the effective data band extended from 1.0 to 0.1 Hz and the effective detection depth was nearly 1000 m with low frequency coil data acquisition and improved RRI inversion.The method used in the super-thick cover layer and deep hidden structure geophysical exploration was effective,which solved the difficulties in the preliminary exploration and provided a reference for geophysical exploration of similar hydropower stations.

关 键 词：地球物理勘察 大地电磁法 二维RRI反演 隐蔽构造 旭龙水电站 

分 类 号：P631[天文地球—地质矿产勘探]