瞬变电磁法浅层分辨率物理模型实验研究

Physical model and experimental research on shallow resolution of transient electromagnetic method

利用物理模型实验,研究了瞬变电磁法对超浅层异常体的探测问题.制作了3套天线装置(重叠回线1、重叠回线2及中心回线),对每一种天线装置分别进行了7个物理模型实验,得到相应的瞬变电磁法多测道剖面图.结果表明:瞬变电磁法响应特征与异常体的尺寸、数量成正比,与异常体的埋深成反比.多匝小回线装置对间距小于边长的两个异常体无法分辨,其分辨率为天线装置边长的2倍.通过改变天线装置尺寸大小及装置类型,瞬变电磁法能对超浅层(小于50cm)异常体进行探测.

The detection problem of ultra-shallow exploration of TEM was studied using physical model experiments. Three antenna devices of TEM （coincident loop 1, coincident loop 2 and central loop） were produced, and seven physical experimental models were designed for each device. The multi-channel sections of TEM were obtained through the experiments. The results show that the response characteristics of TEM are in direct proportion to the size and number of abnormal body, and in inverse proportion to the buried depth. Multi-turn little loop cannot distinguish when the distance between two abnormal bodies is less than the side length of the device, of which the resolution is two times of the length of antenna device. By changing the size and the type of the antenna device, TEM can detect ultra-shallow （less than 50 cm） abnormal body.