TEM小线框技术在近地表结构中的应用——以徐州市淮塔地基结构研究为例  

APPLICATION OF TEM WITH SMALL COILS IN INVESTIGATING THE STRUCTURE OF THE NEAR SURFACE: CASE FOR THE INVESTIGATING OF UNDERGROUND STRUCTURE IN HUAIHAI TOWER, XUZHOU CITY

作　　者：曹国栋[1] 刘树才[2] 刘庆生[1] 

机构地区：[1]中国地质大学地球物理与空间信息学院,武汉430074 [2]中国矿业大学资源与地球科学学院,江苏徐州221008

出　　处：《工程地球物理学报》2005年第4期270-275,共6页Chinese Journal of Engineering Geophysics

摘　　要：多匝小线框装置的瞬变电磁法(TEM)在工程中的应用逐渐增多。在众多实践中发现其探测深度比传统理论深度大得多。本文讨论了TEM小线框在近地表结构研究中探测的极限探深,进行了两种装置的TEM小线框实验,并与直流电法结果对比,虽然小线框TEM具有较高异常分辨能力,但是反演视电阻率和视深度偏小。直流三极法视电阻率为10～30Ω·m,而10m框TEM反演视电阻率为0～10Ω·m,反演深度约100m;而5m框是0～8Ω·m,深度约60m。回线尺寸越小视电阻率就越小。本文同时对比了两种TEM装置的电位衰减曲线、探测深度和两种视电阻率,讨论了TEM小线框的一般方法技术和应用问题,例如与晚期计算公式相比,全区视电阻率受装置影响较小,适合应用于TEM小线框反演。TEM （Transient Electrical Method） method with small coils and multiple circles is applied more and more in underground engineering field today. In the practice, it＇s found that the depth of the method is larger than it has been thought before. This paper introduced about utmost depth of the TEM method first. Two kinds of equipment of the method were then applied on the survey line where DC resistivity exploration had been conducted. By being compared with the result of DC exploration, this method was effective in discovering geoelectric abnormity. But its inversion apparent resistivity and apparent depth were rather less, and revealed a tendency that both the apparent resistivity and apparent depth would become much less while the square of the coils was smaller. The apparent resistivity of DC method was from 10 to 30Ω · m,while the TEM with two kinds of equipment （10× 10×2 and 5×5× 4 ：overlap） was 0-10Ω· m and 0-8Ω· m,with apparent depth of 100m and 60m. Comparing the v-t curves, the depth of exploration, the apparent resistitity of the two kinds of equipment of the TEM method had been completed and the general technology and problems in application of this method had been discussed.

关 键 词：电法勘探 瞬变电磁法 小线框 地基结构 

分 类 号：P631.325[天文地球—地质矿产勘探]