Research and Implementation of Deep Underground Target Detection Based on TEM

Currently, instruments using the Transient Electromagnetic Method (TEM) for target detection are mostly applied in ground, aerial, and marine fields. However, their theoretical methods are no longer suitable for underground spaces, and there are few instruments for deep underground target detection. Particularly in deep underground areas where metal casing exists, conventional detection methods cannot penetrate the casing to measure the target, and the electrode method for measuring through the casing poses various issues, often leading to unsatisfactory results. In order to detect deep underground targets, a theoretical method using the Transient Electromagnetic Method (TEM) for measuring target information beyond metal casings and an axisymmetric differential electromagnetic probe have been proposed. System circuit designs have been completed and a transient instrument suitable metal casings in deep underground environments has been developed.