矿井巷道瞬变电磁超前探技术理论研究

he electrical characteristics of tunneling roadway is analysed to provide the theoretical foundation of using mine transient electromagnetic methods. The theoretical waveform curve of the transient electromagnetic response is given based on the relationship between the primary field and the secondary field. The multi-turn ,small side coincident loop is choosed to be the transmitting and receiving loop as the result of the limited roadway space . The whole space apparent resistivity and depth calculation formulas are derived based on Smoke Ring Effect under the conditions of the coincident loop. The results show that transient electromagnetic method is more sensitive in low resistivity body compared to high resistivity body. There is 20 meters blind zones as a result of turn-off time.The result should be helpful for the application of mine transient electromagnetic methods.