Research On The Key Technology Of The Mine-used Transient Electromagnetic Instrument For Borehole And Roadway

Transient electromagnetic method is an important geophysical detection technology.It is mainly used to detect abnormal bodies such as water-bearing geological body and water-conducting structure in underground coal mines.The mine transient electromagnetic method has the advantages of simple and quick operation as well as low cost.It has been widely used in many coal mines and plays an important role in the safety production of coal mine.However,with the continuous improvement of the mechanization and production capacity of coal mines and the continuous increase of mining depth,higher requirements are imposed on the detection accuracy of mine-use transient electromagnetic equipment.In view of the difficulties encountered underground of the transient electromagnetic method,this paper studies the feasibility of the transient electromagnetic method used in borehole and roadway in mines,designs a transient electromagnetic device used in borehole and roadway,carried out researches on the key technologies realized through the multiplex composite emissionand three-component magnetic induction receiver probe,and tested a transient electromagnetic instrument to improve the detection accuracy and the detection distance,providing favorable technical support for safe and efficient production of coal mines.The main achievements are as follow:(1)Based on the basic principle of the transient electromagnetic detection in borehole and roadway,the magnetic field characteristics of the emission coil with different shapes were studied,and the shape and turns of the transmitting coil were determined.According to the principle of vector superposition of magnetic induction intensity in multi field space,the implementation scheme of multi-channel synthetic emission technology was designed,and the synthetic emission circuit was developed.(2)By studying the characteristics of the transient electromagnetic field signal,and the relationship between the magnetic material and the received signals,a implementation scheme for a three-component magnetic induction plus attitude measurement receiving probe was studied and implemented,and a small-size,threecomponent magnetic induction probe and its internal differential amplifier circuit,signal switching circuit,and attitude control circuit were designed to measure the abnormal body orientation.(3)The developed borehole transient electromagnetic device was tested in the laboratory and in an underground coal mine.It was proved that the mine–used transient electromagnetic instrument for borehole and roadway has the advantages of light weight,fast shut-off speed,three-component sampling,and large dynamic range.The technology of multiplex composite emissionmeets the design requirements;the threecomponent receiving magnetic induction probe has stable performance and high reliability,and the detection effect can meet the requirements.The transient electromagnetic instrument for borehole and roadway designed and developed in this paper can be applied to the prevention and control of water hazards in the underground complex environment,and has a certain guiding significance for further research in related fields.