Mine radio wave exploration method based on multiple emission sources

Abstract

The invention discloses a mine radio wave exploration method based on multiple emission sources, and the method comprises the steps: arranging a plurality of emission sources and a plurality of receiving points in roadways at two sides of a working surface, enabling each emission source to excite and generate electromagnetic waves at the same time, and enabling each receiving point to continuously receive electromagnetic wave data fed back by different emission sources; in this way, a signal network with wide coverage can be formed, the limitation of a single emission source is overcome, and the requirement for the detection area of the whole working face area is met. Fusing the electromagnetic wave data received by each receiving point, greatly increasing the density of exploration data and enhancing the field intensity value of each position due to the effect of a superimposed effect, and finally obtaining an electromagnetic wave attenuation tomography result of the working surface area by calculating the attenuation coefficient of each receiving point; the method can effectively improve the detection precision and resolution of the geological anomalous body, obtains more detailed geological information, and can cover the working face area needing to be detected through one-time construction, thereby effectively improving the construction efficiency.

Description

Technical Field

[0001] The invention relates to a mine radio wave exploration method based on multiple emission sources, belonging to the technical field of mine exploration. Background Art

[0002] In modern coal mine exploration technology, accurate and rapid acquisition of underground geological information plays a vital role in the efficiency and safety of the mining industry. Traditional exploration methods, such as geological drilling and seismic exploration, can provide certain underground information, but they usually have problems such as high cost, long cycle and complex operation, especially in the mine environment. Compared with traditional exploration methods, the instruments required for mine radio wave exploration are light and require fewer operators. Therefore, mine exploration technology is more efficient and convenient, which has become the focus of application.

[0003] Conventional radio wave exploration is a single emission source. The strong electrical interference and radio frequency signal interference of electrical equipment in mines and good metal conductors (such as metal brackets, metal pipes, rails and cables, etc.) will seriously interfere with the signal propagation of radio wave exploration, making it difficult to meet the high-precision requirements of mine exploration. In addition, as the width of the working face increases, the existing radio wave exploration method has the problem of insufficient power of the excitation equipment, resulting in the inability to cover the entire working face, and the accuracy and resolution of geological anomaly detection are low. At present, in order to solve this problem, the only way is to increase the transmission power of the excitation equipment, but increasing the transmission power involves the increase in the size of the excitation equipment and the problem of mine explosion-proof type.

[0004] Therefore, how to provide a new mine radio wave exploration method that can form a signal network covering the required detection area when exploring mines based on existing electromagnetic wave exploration equipment, and ultimately effectively improve the accuracy and resolution of geological anomaly detection, is the research direction required by the present invention. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a mine radio wave exploration method based on multiple emission sources. By deploying multiple existing electromagnetic wave exploration equipment and simultaneously exciting electromagnetic waves to form a field strength superposition effect, a signal network covering the required detection area can be formed when exploring the mine, ultimately effectively improving the accuracy and resolution of geological anomaly detection.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a mine radio wave exploration method based on multiple emission sources, the specific steps are:

[0007] Step 1: Arrange electromagnetic wave exploration equipment: Arrange multiple electromagnetic wave transmitting devices at equal intervals along the direction of the lane on one side of the working face to continuously transmit electromagnetic waves to the working face; arrange multiple receiving points at equal intervals along the direction of the lane on the other side of the working face, and place a receiving device at each receiving point to receive electromagnetic wave data passing through the working face, so that the electromagnetic wave field covers the entire working face; then calibrate the position coordinates of each electromagnetic wave transmitting device and each receiving point;

[0008] Step 2: Obtaining electromagnetic wave detection data: Start each electromagnetic wave transmitting device, so that each electromagnetic wave transmitting device simultaneously transmits electromagnetic waves to the working surface, and each receiving point continuously receives electromagnetic wave data that passes through the working surface and reaches its respective position;

[0009] Step 3: Determine the attenuation coefficient of each receiving point:

[0010] ① According to the principle of electromagnetic wave field superposition, the magnetic field strength of any point in the electromagnetic wave field can be superimposed by the magnetic field strengths of several electromagnetic waves. Its mathematical expression is expressed as follows:

[0011] H m =H1+H2+H3+……+H N (1)

[0012] Among them, H m It is the field strength value after multiple electromagnetic wave signals are superimposed at a certain point in space, m = 1, 2, ... M; H1 represents the field strength value of the electromagnetic wave emitted by the first electromagnetic wave transmitting device to the point, H N Indicates the field strength value of the electromagnetic wave emitted by the Nth electromagnetic wave transmitting device radiating to this point;

[0013] ② Using the above electromagnetic wave field strength superposition principle, multiple electromagnetic wave transmitting devices distributed at equal intervals are approximated as linear transmitting sources in a straight line, and the linear transmitting sources are discretized, that is, the field strength value of each receiving point is formed by the superposition of a large number of point source attenuation field values; the field strength attenuation formula of each point source is expressed as:

[0014]

[0015] Where: n = 1, 2, ... N, H n is the field strength value of the nth transmitting source at the receiving point; H0 is the initial field strength value of each transmitting source; r n is the distance from the nth transmitting source to the receiving point; β is the attenuation coefficient of the electromagnetic wave during propagation;

[0016] ③ Assuming that the attenuation coefficient β of the electromagnetic waves excited by each emission source at the same receiving point is consistent, combining formulas (1) and (2), we can get:

[0017]

[0018] Since the field value H after superposition at each receiving point m It is obtained by receiving electromagnetic wave data at each receiving point, that is, H m are known values; and H0 and r n are all known values, from which the attenuation coefficient β of the electromagnetic wave data received by each receiving point can be calculated m ;

[0019] Step 4: Tomography: According to the attenuation coefficient β of each receiving point obtained in step 3 m , and determine that the initial field strength value of the electromagnetic wave emitted by each discrete emission source is H0. According to formula (2), ΔH=H0-H n It is a value related to the attenuation coefficient and propagation distance. According to the radio wave exploration theory, after taking the logarithm of the field strength value, the electromagnetic wave field is approximated as linear attenuation, that is:

[0020] lnH0-lnH n =β m × n (4)

[0021] Where: n = 1, 2, ... N, m = 1, 2, ... M;

[0022] According to the above process, combined with step 3, the attenuation coefficient β corresponding to each receiving point is obtained m The working surface area is meshed, and finally the SIRT algorithm is used to solve the attenuation, and finally the electromagnetic wave attenuation tomography results of the working surface area are obtained.

[0023] Furthermore, each electromagnetic wave transmitting device generates electromagnetic waves with the same field strength, which is convenient for subsequent calculation and tomographic imaging.

[0024] Furthermore, the models of the electromagnetic wave transmitting devices are the same, and the models of the receiving devices are the same.

[0025] Furthermore, each electromagnetic wave transmitting device is a magnetic dipole, and the receiving device uses a multi-turn coil to measure the field strength value. With this receiving device, the measured value is the magnetic component of the electromagnetic wave, making the measured value more accurate.

[0026] Working principle of the present invention: Radio wave exploration of mines is based on the propagation of electromagnetic waves in coal seams. Geological anomalies will aggravate the energy attenuation of electromagnetic waves, and the geological structure is indirectly explored through energy attenuation coefficient imaging. According to the electromagnetic wave propagation theory, the inventor further discovered that different electromagnetic waves can be superimposed at the same position during the propagation process (that is, when the same position receives different electromagnetic waves at the same time, a superposition effect will occur), thereby increasing the field strength value at that position; the exploration method of the present invention is formed on the basis of this research discovery, such as Figure 1 As shown, multiple transmitting sources are evenly distributed in the tunnel. After simultaneously exciting and generating continuous electromagnetic waves, different electromagnetic waves will produce a superposition effect at different positions in the working face area, thereby improving the signal strength at each position to a certain extent. Ultimately, it is ensured that the field strength value at any receiving point can reach a high value, which is convenient for analysis and processing, and improves the exploration coverage and detection accuracy.

[0027] Compared with the prior art, the present invention utilizes the principle of simultaneous excitation to form a superposition effect discovered above. By arranging multiple uniformly distributed and linear emission sources in the tunnel on one side of the working face, and arranging a row of multiple equally spaced receiving points on the other side of the working face, and the row is parallel to the straight line formed by the emission sources, each emission source is subsequently excited to generate electromagnetic waves at the same time, and each receiving point continuously receives electromagnetic wave data fed back by different emission sources. This method can form a signal network with wide coverage, overcome the limitations of a single emission source, and meet the detection area of ​​the entire working face area. Then, the electromagnetic wave data received by each receiving point are fused and processed. Due to the superposition effect, the density of exploration data can be greatly increased and the field strength value at each position can be enhanced. By calculating the attenuation coefficient of each receiving point and combining the distance of each receiving point relative to each transmitting source, the working face area is gridded, and finally the SIRT algorithm is used to solve the attenuation of different grid positions, and the field strength value data of the electromagnetic wave after attenuation in different grids in the working face area are obtained, and finally the electromagnetic wave attenuation tomography results of the working face area are obtained; this method can effectively improve the accuracy and resolution of geological anomaly detection, obtain more detailed geological information, and because it uses existing equipment, it is convenient for construction layout, and the working face area required for detection can be covered in one construction, thereby effectively improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the principle of superposition effect on which the present invention is based;

[0029] Figure 2 It is a schematic diagram of the layout of the electromagnetic wave exploration equipment in the present invention;

[0030] Figure 3 It is a tomographic image of the working surface area after the treatment of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below.

[0032] like Figure 2 As shown, the specific steps of the present invention are:

[0033] Step 1. Lay out electromagnetic wave exploration equipment: Lay out multiple electromagnetic wave transmitting devices at equal intervals along the direction of the tunnel on one side of the working face, which are used to continuously transmit electromagnetic waves to the working face. Lay out multiple receiving points at equal intervals along the direction of the tunnel on the other side of the working face, and place a receiving device at each receiving point to receive electromagnetic wave data passing through the working face, so that the electromagnetic wave field covers the entire working face; then calibrate the position coordinates of each electromagnetic wave transmitting device and each receiving point; each electromagnetic wave transmitting device excites electromagnetic waves with the same field strength value. The models of each electromagnetic wave transmitting device are the same, and the models of each receiving device are the same; this facilitates subsequent calculations and tomographic imaging. In addition, each electromagnetic wave transmitting device is a magnetic dipole, and the receiving device uses a multi-turn coil to measure the field strength value. With this receiving device, the measured value is the magnetic component of the electromagnetic wave, which makes the measured value more accurate.

[0034] Step 2: Obtaining electromagnetic wave detection data: Start each electromagnetic wave transmitting device, so that each electromagnetic wave transmitting device simultaneously transmits electromagnetic waves to the working surface, and each receiving point continuously receives electromagnetic wave data that passes through the working surface and reaches its respective position;

[0035] Step 3: Determine the attenuation coefficient of each receiving point:

[0036] ① According to the principle of electromagnetic wave field superposition, the magnetic field strength of any point in the electromagnetic wave field can be superimposed by the magnetic field strengths of several electromagnetic waves. Its mathematical expression is expressed as follows:

[0037] H m =H1+H2+H3+……+H N (1)

[0038] Among them, H m It is the field strength value after multiple electromagnetic wave signals are superimposed at a certain point in space, m = 1, 2, ... M; H1 represents the field strength value of the electromagnetic wave emitted by the first electromagnetic wave transmitting device to the point, H N Indicates the field strength value of the electromagnetic wave emitted by the Nth electromagnetic wave transmitting device radiating to this point;

[0039] ② Using the above electromagnetic wave field strength superposition principle, multiple electromagnetic wave transmitting devices distributed at equal intervals are approximated as linear transmitting sources in a straight line, and the linear transmitting sources are discretized, that is, the field strength value of each receiving point is formed by the superposition of a large number of point source attenuation field values; the field strength attenuation formula of each point source is expressed as:

[0040]

[0041] Where: n = 1, 2, ... N, H n is the field strength value of the nth transmitting source at the receiving point; H0 is the initial field strength value of each transmitting source; r n is the distance from the nth transmitting source to the receiving point; β is the attenuation coefficient of the electromagnetic wave during propagation;

[0042] ③ Assuming that the attenuation coefficient β of the electromagnetic waves excited by each emission source at the same receiving point is consistent, combining formulas (1) and (2), we can get:

[0043]

[0044] Since the field value H after superposition at each receiving point m It is obtained by receiving electromagnetic wave data at each receiving point, that is, H m are known values; and H0 and r n are all known values, from which the attenuation coefficient β of the electromagnetic wave data received by each receiving point can be calculated m ;

[0045] Step 4: Tomography: According to the attenuation coefficient β of each receiving point obtained in step 3 m , and determine that the initial field strength value of the electromagnetic wave emitted by each discrete emission source is H0. According to formula (2), ΔH=H0-H n It is a value related to the attenuation coefficient and propagation distance. According to the radio wave exploration theory, after taking the logarithm of the field strength value, the electromagnetic wave field is approximated as linear attenuation. The formula is as follows:

[0046] lnH0-lnH n =β m × n (4)

[0047] Where: n = 1, 2, ... N, m = 1, 2, ... M;

[0048] It is known that the field strength value at a certain receiving point is H m , assuming that the emission source is approximately differentiated into n point sources, the corresponding attenuation coefficient β is calculated by formula (3) m and ΔH, repeating the above process, we can get M β mand ΔH; the working surface area is meshed and each emission source is traced linearly to obtain the propagation path length r′ reaching each grid; the electromagnetic wave attenuation coefficient β is set as the variable, and the formula (4) can be used to construct a large coefficient matrix, and the plane distribution of the electromagnetic wave attenuation coefficient can be obtained by solving the parameter β in each grid; and the mature SIRT algorithm is used to solve the coefficient β, and the electromagnetic wave attenuation coefficient in different grids of the working surface is calculated, and finally the electromagnetic wave attenuation tomography result of the working surface area is obtained as follows Figure 3 shown.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A mine radio wave exploration method based on multiple transmitting sources, characterized in that: The specific steps are: Step 1: Arrange electromagnetic wave exploration equipment: Arrange multiple electromagnetic wave transmitting devices at equal intervals along the direction of the lane on one side of the working face to continuously transmit electromagnetic waves to the working face; arrange multiple receiving points at equal intervals along the direction of the lane on the other side of the working face, and place a receiving device at each receiving point to receive electromagnetic wave data passing through the working face, so that the electromagnetic wave field covers the entire working face; then calibrate the position coordinates of each electromagnetic wave transmitting device and each receiving point; Step 2: Obtaining electromagnetic wave detection data: Start each electromagnetic wave transmitting device, so that each electromagnetic wave transmitting device simultaneously transmits electromagnetic waves to the working surface, and each receiving point continuously receives electromagnetic wave data that passes through the working surface and reaches its respective position; Step 3: Determine the attenuation coefficient of each receiving point: ① According to the principle of electromagnetic wave field superposition, the magnetic field strength of any point in the electromagnetic wave field can be superimposed by the magnetic field strengths of several electromagnetic waves. Its mathematical expression is expressed as follows: H m =H1+H2+H3+……+H N (1) Among them, H m It is the field strength value after multiple electromagnetic wave signals are superimposed at a certain point in space, m = 1, 2, ... M; H1 represents the field strength value of the electromagnetic wave emitted by the first electromagnetic wave transmitting device to the point, H N Indicates the field strength value of the electromagnetic wave emitted by the Nth electromagnetic wave transmitting device radiating to this point; ② Using the above electromagnetic wave field strength superposition principle, multiple electromagnetic wave transmitting devices distributed at equal intervals are approximated as linear transmitting sources in a straight line, and the linear transmitting sources are discretized, that is, the field strength value of each receiving point is formed by the superposition of a large number of point source attenuation field values; the field strength attenuation formula of each point source is expressed as: Where: n = 1, 2, ... N, H n is the field strength value of the nth transmitting source at the receiving point; H0 is the initial field strength value of each transmitting source; r n is the distance from the nth transmitting source to the receiving point; β is the attenuation coefficient of the electromagnetic wave during propagation; ③ Assuming that the attenuation coefficient β of the electromagnetic waves excited by each emission source at the same receiving point is consistent, combining formulas (1) and (2), we can get: Since the field value H after superposition at each receiving point m It is obtained by receiving electromagnetic wave data at each receiving point, that is, H m are known values; and H0 and r n are all known values, from which the attenuation coefficient β of the electromagnetic wave data received by each receiving point can be calculated m ; Step 4: Tomography: According to the attenuation coefficient β of each receiving point obtained in step 3 m , and determine that the initial field strength value of the electromagnetic wave emitted by each discrete emission source is H0. According to formula (2), ΔH=H0-H n It is a value related to the attenuation coefficient and propagation distance. According to the radio wave exploration theory, after taking the logarithm of the field strength value, the electromagnetic wave field is approximated as linear attenuation, that is: lnH0-lnH n =β m ×r n (4) Where: n = 1, 2, ... N, m = 1, 2, ... M; According to the above process, combined with step 3, the attenuation coefficient β corresponding to each receiving point is obtained m The working surface area is meshed, and finally the SIRT algorithm is used to solve the attenuation, and finally the electromagnetic wave attenuation tomography results of the working surface area are obtained.

2. The mine radio wave exploration method based on multiple transmitting sources according to claim 1 is characterized in that: Each electromagnetic wave transmitting device generates electromagnetic waves with the same field strength value.

3. The mine radio wave exploration method based on multiple transmitting sources according to claim 1 is characterized in that: The models of various electromagnetic wave transmitting devices are the same, and the models of various receiving devices are the same.

4. The mine radio wave exploration method based on multiple transmitting sources according to claim 1, characterized in that: Each electromagnetic wave transmitting device is a magnetic dipole, and the receiving device uses a multi-turn coil to measure the field strength value.

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