基于高频大地电磁法的优势渗流通道识别研究  

Research on the Identification of Dominant Seepage Channels Based on High Frequency Electromagnetic Method

作　　者：闫永帅 霍继炜 高宇甲 姜彤[2] 张俊然[2] 刘江江 朱云江 YAN Yongshuai;HUO Jiwei;GAO Yujia;JIANG Tong;ZHANG Junran;LIU Jiangjiang;ZHU Yunjiang(Hefei University of Technology,Hefei 230009,China;North China University of Water Resources and Electric Power,Zhengzhou 450046,China;The Fourth Construction Co.,Ltd.of CSCEC 7th Division,Xi′an 710016,China)

机构地区：[1]合肥工业大学,安徽合肥230009 [2]华北水利水电大学,河南郑州450046 [3]中建七局第四建筑有限公司,陕西西安710016

出　　处：《华北水利水电大学学报（自然科学版）》2022年第4期76-82,共7页Journal of North China University of Water Resources and Electric Power：Natural Science Edition

基　　金：国家自然科学基金项目(41602295)。

摘　　要：函谷关隧道工程是新国道G310(连云港—天水市)的重要连接工程,全线长1.99 km,最大埋深108 m。工程主体位于第四系黄土状粉土地层中,其上部存在一条易积水无防渗的地下暗渠。沿暗渠的潜在地下水优势渗流及其诱发的土体变形、塌陷是隧道工程建设与安全运行面临的重要挑战。鉴于传统钻探方法难以连续、全面地揭示暗渠附近渗流体系的发育特征,结合高频大地电磁法(Eh4)与实地勘察,通过获取地下介质的电阻率特性,识别遗存暗渠位置并对比其实际位置,阐明始于暗渠演化形成的优势渗流通道的分布特征。同时,揭示Eh4在识别地下潜在入渗空间或通道领域的有效性。结果显示:在测线4高程525 m位置出现的系列高电阻率空腔与暗渠实际位置较吻合,测线4不同高程位置处出现的2处低电阻率区Y_(1)、Y_(2)良好对应了暗渠转向处的2口人工开挖竖井,均证实了利用Eh4识别优势渗流空间的有效性;测线1、2处的电阻率随水平距离的增加产生明显波动,发育2处低电阻率区,反映了该处地下水优势渗流通道呈分叉状。无强降雨或强地表流水冲蚀下,上述Eh4识别的优势渗流体系极可能始于暗渠转向处2口人工竖井,在重力驱动下历经暗渠水流的长期冲蚀进一步延伸发育而成,威胁隧道双向工程的稳定性。这些结论对掌握地下工程地质条件非常重要,为新国道G310函谷关隧道建设的安全、稳定、可控提供了技术支撑。Hanguguan Tunnel is an important building of the new national highway G310(Lianyungang-Tianshui City),with a total length of 1.99 km and a maximum buried depth of 108 m.The main body of the project is located in the Quaternary loess-like silt stratum, and there is an underground ditch in the upper part that is easy to accumulate water. The main body of the project is located in the Quaternary loess-like silt stratum, and there is an underground ditch in the upper part that is easy to accumulate water and has no seepage prevention. The potential dominant seepage of groundwater along the underground channel and the induced soil deformation and collapse are major challenges for the construction and safe operation of tunnel engineering. In view of the difficulty of traditional drilling methods to continuously and comprehensively reveal the development characteristics of the seepage system near the culvert, the high-frequency electromagnetic method (Eh4) is combined with field investigation. By obtaining the resistivity characteristics of the underground medium, identif-ying the location of the remaining underdrain and comparing its actual location, this paper expounds the distribution charac-teristics of the dominant seepage channels formed from the evolution of the underdrain. At the same time, the effectiveness of Eh4 in identifying potential subsurface infiltration spaces or channels is revealed. The results are as follows. The series of high resistivity cavities at the elevation of 525 m of survey line 4 are in good agreement with the actual location of the cul-vert. The two low-resistivity areas Y_(1) and Y_(2) at different elevations of line 4 correspond well to the two artificially excavated shafts at the turn of the underdrain, which both confirm the effectiveness of using Eh4 to identify the dominant seepage space. The resistivities at survey lines 1 and 2 fluctuate significantly with the increase of horizontal distance, and two low resistivity areas are developed, reflecting the bifurcation of the dominant

关 键 词：高频大地电磁法(Eh4) 黄土 暗渠 优势渗流通道 

分 类 号：P631[天文地球—地质矿产勘探]