Device and method for realizing transient electromagnetic focusing detection of mine

Abstract

The invention discloses a device and a method for realizing transient electromagnetic focusing detection of a mine, wherein the device and the method belong to the field of geophysical electromagnetic exploration technology. The invention aims to supply the device and the method which realize focusing detection and improve exploration depth and precision by means of a magnetic field superposing principle. The device and the method are characterized in that two multi-turn coils which are in the same plane and are totally same form a transmitting device; the transmitting device is connected with a transient electromagnetic explosion-proof host machine in parallel; a certain distance exists between the two coils and furthermore the distance can be properly adjusted according to an actual detection space; the current with same amplitude and same direction is applied to the two transmitting coils; and an induction electromagnetic wave signal is received at symmetrical position relative to a line between centers of the two coils as an axis by means of a receiving device. The device and the method have advantages of focusing an underground eddy current electromagnetic field to a detection area, increasing an exploration depth and realizing targeted detection. Furthermore the detection effect of the method and the device is remarkably improved than that of a traditional mine transient electromagnetic transceiver device.

Description

technical field [0001] The invention discloses a device and method for realizing transient electromagnetic focusing detection in mines, and belongs to the technical field of geophysical electromagnetic exploration. Background technique [0002] Transient electromagnetic or time domain electromagnetic methods (TEM for short), it uses ungrounded return line or grounding line source to transmit a pulsed magnetic field to the ground, during a pulsed magnetic field gap, use a coil or a grounded electrode to observe Secondary vortex field method. Its basic working method is to set a transmitting coil with a certain waveform current on the ground or in the air, so as to generate an electromagnetic field in the surrounding space, and generate an induced current in the underground conductive rock ore body. And decay over time. The geoelectric characteristics at different depths can be obtained by measuring the time-varying law of the secondary field in each time period after power ...

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Problems solved by technology

[0006] (1) As the transmitting coil, the number of turns of the coil group used is too much, which leads to the increase of the capacitance and inductance inside the coil, and also makes the transient electromagnetic shutdown time too long, and the detection blind zone increases;

[0007] (2) As the transmitting coil, the enameled wire of the coil group used is too thin, resulting in too large internal resistance of the coil group. Under the premise of ensuring a certain transmission power, a high-intensity working voltage needs to be applied, which brings safety hazards to underground work and production. ;

[0008] (3) After the manufacturing and packaging of the magnetic focusing coil is completed, its focusing ability and focusing range are limited to a certain extent, and real-time dynamic adjustment of the focusing ability and focusing range cannot be performed.

[0011] (1) For the hemispherical coil array and the circular surface coil array mentioned in the article, once the radius of the sub-coil is determined, it can only focus on a certain range, and cannot dynamically adjust the focusing ability and focusing range in real time.

Moreover, the number of coils forming the array is too large, the design is difficult, and the construction in the underground roadway is difficult. The increase in the number of coils leads to enhanced mutual inductance, which brings greater interference to the received signal;

[0012] (2) Due to the small overlapping area of ​​the rectangular surface coil array mentioned in the paper, the focusing ability is weak and the dynamic focusing range becomes smaller, so it is necessary to take into account the placement of the best measurement position during the detection process; different rectangular coils are in the Different planes and connected in series, it is difficult to lay out, fix and construct underground roadways, which seriously affects work efficiency

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