【作者】 周胜；

【导师】 席振铢；

【作者基本信息】 中南大学 ， 地球探测与信息技术， 2011， 硕士

【摘要】 坑道瞬变电磁法是瞬变电磁法的应用拓展,其在最接近目标体的地下空间展开工作,具有反应灵敏、装置灵活、工作效率高等特点,在金属矿山盲矿体的预测、煤田巷道不良地质体的空间定位、隧道超前预报等领域具有重要的应用意义。本文从Maxwell方程出发,推导了层状介质全空间磁偶极子的瞬变场,计算其响应结果；从理论和实验的角度,分析了变频测量技术和全程采样技术在坑道内探测近距离地质信息的可能性；实验研究了改进RCD网络关断电路、准谐振关断电路和串联RC网络关断电路的电流关断特性,发展了一种新型瞬变电磁发射技术一组合发射技术；通过试验,研究了在方形发射天线、多孔径发射天线和多角度的矩形叠加天线激励下,天线后方低阻板状体对前方低阻板状体响应的影响。结果表明：瞬变电磁的全空间响应与半空间相比幅值和形态都发生了较大的变化,实际应用时不能单纯看做半空间处理,显然发展特种天线技术,突出天线前方一次场,减弱后方一次场是十分必要的。在天线固定的情况下,变频测量技术受制于电流关断延时,高频测量极有可能进入关断线性区,测量数据产生畸变,近距离地质信息丢失严重；全程采样技术从关断一次场强信号中分离二次场弱信号,数据采集和后期处理难度大；显然这两种方法都不适宜在坑道内开展。通过设计组合发射技术,在高频发射时,小电感量天线处于发送状态,此时关断延时短,测量早期道数据,在低频发射时,大电感量天线处于发送状态,此时关断延时长,测量晚期道数据,实验证明组合发射技术可以有效的提取了近距离和远距离的地质信息；通过试验发现方形发射天线、多孔径发射天线和水平矩形叠加天线的抗干扰能力差,而120°和90°矩形叠加天线由于后方一次场受到约束,能有效分辨前方目标体的响应,抗干扰能力强。更多还原

【Abstract】 Tunnel transient electromagnetic method is expanding the application of transient electromagnetic method.It starts works in the underground space closest to the target,with sensitive response, flexible devices,high efficiency features and so on.It plays a import role to the blind ore exploration in metal mines, the adverse geological position in coal tunnels,the tunnel prediction.From the Maxwell equation, derived transient magnetic dipole field of the whole space layered media, calculated typical geological models. From the theory and experiments,analyzed the possibility to survey geological information by means of frequency conversion measurement and all time TEM. Studied the characteristics of improved RCD network shut-off technique,quasi-resonant shut-off technique and series RC network shut-off technique.Created a new transmitting technology called combined transmitting technolog. Studied the influences from responses of behind plates to responses of front plates,when they were stimulated by square transmitting antenna, multi-angle transmitting antenna and rectangle superimposed transmitting antenna.The results show that:The whole space responses are different from half-space responses, the actual measurements can not be ignored, it is necessary to develop transmitting special antenna in order to weak Induced secondary field from the rear. Frequency conversion measurement and all time TEM are easy to measure into current turn-off time,which causes early data aberration,so they can’t be used in tunnel.The author proposed combined transmitting technolog.It uses small inductance antenna to obtain a short turn-off delay, measuring shallow geological information;It uses high inductance antenna to measuring distance geological information. Tht experiments showed that combined transmitting technolog is effective. Tht experiments showed that the anti-interference ability of square transmitting antenna, multi-angle transmitting antenna and horizontal rectangle superimposed transmitting antenna is poor,but the 120°and 90°rectangle superimposed transmitting antennas can effectively distinguish the response from front geological bodies.更多还原