阵列式多路同步瞬变电磁定向探测模式研究

基于阵列式分布的多路接收线圈系对靶区同步定向探测是一种新的探测模式,采用与目标体一定距离的单个线圈为发射源,多个接收线圈系垂直布设在源线圈与目标体之间的布设方式;以多路信号通过导线同步连接至瞬变电磁发射机,在同一时刻采集不同空间位置的目标体异常场。相比于传统瞬变电磁法的单道接收,多路线圈系所测量的感应信号具有矢量特性。发射线框周围和后方干扰源的响应信号以及接收线圈系间的互感信号呈现向前衰减规律,前方目标体的异常响应信号表现为增强的变化规律,根据有规律向前增强信号的幅度和变化特征对前方有无低阻体进行判定。算例结果表明,阵列式多路同步瞬变电磁定向探测技术,在解决隧道中存在的目标体方位定向困难及异常识别不准确等问题具有优势,可为超前预报的研究工作提供指导意见。

Study on Transient Electromagnetic Directional Detection Mode of Multichanneland Synchronous Array

Based on the multichannel receiving coils of array distribution,the synchronous and directional detection for target area is a new detecting mode.This paper uses single coil as the emission source with a certain distance from the target and the several receiving coils are vertically laid out between the source coil and the target.The Multi-channel signals are synchronously connected with the transient electromagnetic transmitter by wire to acquire the target anomaly field of different spatial positions at the same time.Compared with the traditional TEM method of single channel reception,the inductive signal measured by multichannel coils system has vector characteristics.It shows the rule of forward attenuation for the response signal around the emission line frame and behind the interference source and for the mutual inductance signal between the receiving coil system.In addition,the abnormal response signal of the front target shows the rule of enhancement.Whether there is a low resistivity body ahead can be judged according to the characteristics of the amplitude and the change of the regular forward signals.The calculation results show that the transient electromagnetic directional detection technology of multichannel and synchronous array has the advantage in solving these problems such as orientated difficulties of objects and inaccuracy of abnormal recognition,which can provide guidance for the research work of advanced prediction.