CN115576022A

CN115576022A - Electric monitoring system and method for mine water damage hidden danger

Info

Publication number: CN115576022A
Application number: CN202211552887.6A
Authority: CN
Inventors: 鲁晶津; 王冰纯; 袁博; 王云宏; 崔伟雄; 蒋齐平; 李博凡; 段建华
Original assignee: CCTEG Xian Research Institute Group Co Ltd
Current assignee: CCTEG Xian Research Institute Group Co Ltd
Priority date: 2022-12-05
Filing date: 2022-12-05
Publication date: 2023-01-06
Anticipated expiration: 2042-12-05
Also published as: CN115576022B

Abstract

The invention discloses an electrical method monitoring system and method for mine water damage hidden danger, wherein the system comprises: the electrical method monitoring system controller is used for sending a control command to the first electrical method monitoring substation and the second electrical method monitoring substation; the first L-shaped measuring line and the second L-shaped measuring line are used for enclosing a rectangle to enclose the working surface; the first electric-method monitoring substation and the second electric-method monitoring substation are respectively connected with the first L-shaped measuring line and the second L-shaped measuring line and used for acquiring electric-method monitoring data; the memory is used for storing, processing and quality control of electrical method monitoring data; the electrical method monitoring data processor is used for accessing the memory and carrying out observation voltage positive and negative attribute correction, electrode polarization effect correction, electrode consistency correction and mixed weight constraint inversion imaging on the electrical method monitoring data. The invention effectively reduces the influence of the underground complex working condition environment on the electric method monitoring, improves the interpretation precision of the mine water disaster hidden danger, and provides technical support for the prevention and control of the coal mine water disaster.

Description

Electric monitoring system and method for mine water damage hidden danger

Technical Field

The invention relates to an electrical monitoring system and method for hidden danger of water damage of a mine, belongs to the field of water prevention and control of the mine, and particularly relates to an electrical monitoring system and method for hidden danger of water damage of the mine, which are suitable for monitoring hidden danger of water damage of complex working condition environments under a coal mine.

Background

At present, international situation is restless, china faces huge energy safety problems, and coal is still an irreplaceable main energy source in China. The coal industry is an important part of national economy in China, and an intelligent geological support system is a basic content for intelligent construction of underground coal mines, and a transparent geological column provides real-time, dynamic and high-precision geological information which is continuously integrated into the production process of the coal mines on the basis of a three-dimensional geological static model and realizes the transparency of the geological information of the mines.

With the policy of 'carbon peak reaching' and 'carbon neutralization' proposed, the development situation of the coal industry becomes more and more severe. In order to realize a safe, green, low-carbon, efficient and intelligent high-quality development mode in the coal industry, the coal mine automation, informatization, intelligentization and unmanned technology is a necessary way for the development of the coal industry. However, most of the coal mine hydrogeological conditions in China are extremely complex, as the mining depth is gradually increased, the water damage threats such as top and bottom plates and old air water burst are increasingly serious, the long-term development of intelligent and unmanned mining technologies of coal mines is greatly restricted, and the transparent driving protection navigation of the geological information of the hidden danger of the water damage of the coal mine is urgently needed.

The regulations of coal mine water control regulations stipulate that mine hydrogeological exploration is comprehensively explored by adopting various geophysical exploration methods, and mainly electrical exploration. As an important means for transparentizing hydrogeological information, the electrical prospecting detects and identifies abnormal regions according to the electrical property difference between abnormal geologic bodies and surrounding rocks, and is sensitive to low resistance abnormity caused by rock water-bearing property change, wherein the direct current resistivity method can flexibly change the arrangement mode of an electrode array according to the difference of detection targets, so that the method is widely applied to water hazard prevention and control in coal mines. The coal mine water control regulations further stipulate that a water inrush monitoring and early warning system should be established by adopting scientific and effective monitoring technologies such as micro-seismic, micro-seismic and electrical method coupling and the like for a hydrological and geological mine threatened by bottom plate confined water, a water inrush monitoring and early warning system is used for detecting a water body and a water guide channel, evaluating the engineering treatment effect such as grouting and the like, and monitoring the change condition of the water guide channel influenced by mining. In the detailed rules, the electrical method monitoring is used as a scientific and effective technical means for monitoring and early warning of water damage.

The method is widely applied to the fields of underground water seepage monitoring, solute transport monitoring, pollution treatment process monitoring, landfill site monitoring, frozen soil area monitoring, landslide body monitoring, water inrush monitoring in the tunneling process, thermal diffusion monitoring, grouting effect monitoring, water damage hidden danger monitoring of a coal face and the like, and obtains good geological effect. The electric method monitoring has been applied to underground coal mines for decades and is an important means for transparentizing water hazard potential geological information, but in the practical application process of underground coal mines, the method still faces technical bottlenecks such as strong electromagnetic interference environment, limited observation space, low imaging precision and the like.

The underground observation space of the coal mine is limited, survey lines are generally arranged along roadways on two sides of a working face when monitoring by an electrical method is carried out, and compared with a ground high-density electrical method, the density of an obtained electrical reconstruction data volume is extremely low, so that the problem of multiple resolvability of an inversion result is particularly prominent in the underground application of the coal mine. Meanwhile, when a survey line is arranged in a roadway, the complex working condition environment is faced, the monitoring data acquisition is greatly interfered, the signal-to-noise ratio of the monitoring data is low, the quality of the monitoring data is poor, the interpretation precision of the monitoring result is further reduced, and the further development of the monitoring result in the field of mine water control is restricted.

The interference sources of the monitoring data mainly come from environmental noise, system errors (including errors introduced by monitoring equipment such as monitoring instruments and monitoring electrodes), shallow non-uniformity change and the like.

The environmental noise mainly comes from large electromechanical equipment under the coal mine. When the mine electrical method monitoring is carried out, large electromechanical equipment such as coal mining machines, belt conveyors and the like in the coal mine continuously operate, and strong electromagnetic interference is brought. The emission power of a general coal mining machine is up to 3000kW, the emission power of a monitoring system is limited to only 6W by coal safety, and strong electromagnetic noise of large electromechanical equipment can cause great interference to an original waveform signal. For strong electromagnetic interference in the underground coal mine, the method can be realized from two aspects of monitoring equipment hardware lifting and signal processing method improvement. A pseudo-random signal transmitting module and a full waveform data acquisition module are adopted on hardware, effective signals are extracted by adopting a relevant identification method on signal processing, the anti-interference capability of the system is improved to a certain extent, but the system is difficult to overcome the problem that the effective signals are weakened after energy is redistributed among different frequencies during multi-frequency wave transmission, a single-frequency wave transmitting mode is still adopted in the actual use process, the advantage of the multi-frequency pseudo-random signals on the anti-interference capability cannot be exerted, and the problem that the acquired signals still face lower signal noise is still solved.

The system error mainly comprises interference introduced by monitoring equipment such as a monitoring instrument and a monitoring electrode. With the continuous improvement of the performance of the electronic element device, the interference introduced by the monitoring instrument can be basically controlled at a lower level. However, the monitoring electrode is buried underground for a long time and is directly contacted with surrounding rocks, and under the high-temperature and high-humidity environment in a coal mine well, the monitoring electrode is extremely easy to corrode and polarize, so that the monitoring data are greatly interfered. If the corrosion resistance and polarization resistance of the electrode are improved by electrode process improvement, the electrode processing cost is increased. However, when monitoring of the water damage potential of the mine is carried out, the risk of lagging water burst is faced in the goaf, generally, in order to realize monitoring of the water burst potential in the goaf, a monitoring electrode gradually enters the goaf in the stoping process of a working face, the electrode in the goaf is difficult to recover, and the monitoring electrode cannot be reused, so that the problem that the reduction of the electrode cost is important to consider in the construction process of monitoring of the water damage potential of the mine is solved. In order to reduce the construction cost, an anchor rod or stainless steel is generally used as a monitoring electrode when monitoring the water damage hidden danger in the roadway, and a copper electrode wrapped on a monitoring cable is used when monitoring the resistivity in the hole. The common electrodes are easy to corrode and polarize in the underground coal mine monitoring environment. How to correct the influence caused by the corrosion and polarization of the common electrode by a data processing method has no related solution disclosed at present.

Shallow non-uniformity variations are mainly caused by face mining failures. Because the monitoring electrodes are generally arranged in the top and bottom rock stratums of the coal seam, the top and bottom rock stratums are influenced by mining stress to break in the working face extraction process, and the resistivity of the layer position of the electrode is locally changed along with the working face extraction. When the local environment is comparatively moist, the ground resistance rate of electrode can reduce rapidly, leads to monitoring facilities's transmitting current increase, surpasss the intrinsic safety limit even, if the current-limiting resistance of the transmission end can not in time be adjusted this moment, monitoring facilities will normally work. For the detection equipment, the current-limiting resistor can be manually adjusted in a manual mode, and the emission current is ensured to be always at the intrinsic safety level. However, there is an urgent need for a method of adaptively adjusting the current limiting resistance for the monitoring device. Furthermore, shallow non-uniformity variations can also cause false anomalies in the monitored data, resulting in degraded monitored data quality.

The electric monitoring mainly comprises two observation methods, namely an electric section and an electric perspective, during data acquisition. An electric monitoring device based on an electric sectioning method generally utilizes a roadway or a drill hole to arrange one or more measuring lines, each measuring line is respectively connected with a monitoring substation, and each monitoring substation receives and transmits automatically and collects electric section observation data. The electric monitoring equipment based on the electric perspective method is characterized in that monitoring cables are generally arranged in a return air roadway and a transportation roadway, two monitoring substations are connected with a measuring line respectively to form an electric perspective method observation system, the two substations transmit and receive each other, and voltage signals penetrating through a working face when the one substation transmits and the other substation receives are collected. Due to the limitation of the underground coal mine observation space, the electric reconstruction data volume obtained by the existing observation method is uneven in spatial distribution, low in density and limited in information contained in the observation data, so that serious multi-solution exists when the electric reconstruction data volume is used for inversion interpretation. For the observation data of the electrical profile, the space positioning capability of the detection result is poor; for the electrical perspective observation data, the resolution of the detection result along the working face inclination (vertical measuring line direction) and the depth direction is poor. In order to solve the above problems, on one hand, an observation system needs to be improved to obtain richer observation data in a limited observation space; on one hand, an inversion method needs to be improved, proper prior information is applied to the resistivity inversion process for constraint, and the imaging resolution of the inversion result on the abnormal body space position and the spread range is improved.

In addition, the existing monitoring system cannot distinguish the positive and negative properties of the voltage when performing data acquisition, and for the monopole-dipole and dipole-dipole working modes, the actual voltage value beyond a certain observation range will have a negative value, so that the observation range can only be limited to the region with the positive voltage when performing data acquisition by using the two working modes. In order to break through the limitation of the observation range, a method for distinguishing the positive and negative attributes of the observation voltage is urgently needed.

In conclusion, the mine water damage hidden danger electrical monitoring method is used for monitoring the water damage hidden danger in a complex working condition environment under a coal mine, and still faces a series of problems that the transmitting current exceeds the intrinsic safety limit due to strong electromagnetic interference of large electromechanical equipment, electrode corrosion and polarization are monitored, and the change of the ground resistivity causes, the observed electrical reconstruction data volume has low space density, the observation range is limited, the inversion imaging resolution ratio is poor and the like, so that the water damage hidden danger monitoring precision in the prior art is low. In view of the above, there is a need for an effective solution.

Disclosure of Invention

From the foregoing, the specific technical problems to be solved by the present invention are as follows:

1. large electromechanical equipment has strong electromagnetic interference;

2. monitoring electrode corrosion and polarization;

3. the change of the grounding resistance rate causes the emission current to exceed the intrinsic safety limit;

4. the observed electric reconstruction data volume has lower spatial density;

5. limited observation range and poor inversion imaging resolution.

In order to solve the related problems or technical defects in the prior art, the invention provides an electric method monitoring system and method for mine water damage hidden dangers.

Hardware level:

1. two L-shaped measuring lines are designed for enclosing a rectangular surrounding working surface so as to solve the problem that the resolution ratio of two parallel straight line measuring lines is lower in the direction vertical to the measuring lines.

2. A first electrical method monitoring substation and a second electrical method monitoring substation are designed and used for correspondingly switching monitoring electrodes on two L-shaped measuring lines under the control of an electrical method monitoring system controller to obtain a combination of a transmitting electrode and a receiving electrode and controlling signal transmitting and receiving and acquisition of electrical method monitoring data.

3. The controller of the electrical method monitoring system is designed and used for sending control instructions to the first electrical method monitoring substation and the second electrical method monitoring substation according to a set electrical method monitoring scheme to achieve collection of electrical method monitoring data. In each electric method monitoring substation, a field source signal transmitting device and a signal collecting device are designed and are respectively used for transmitting field source signals and collecting electric method monitoring data.

4. The method comprises the following steps that a memory is designed and used for storing, processing signals and controlling quality of electric method monitoring data acquired by control and collection of a first electric method monitoring substation and a second electric method monitoring substation; and is used for storing the data processed by the electrical monitoring data processor.

5. The electrical method monitoring data processor is designed and used for accessing the memory, carrying out observation voltage positive and negative attribute correction, electrode polarization effect correction, electrode consistency correction and mixed weight constraint inversion imaging on electrical method monitoring data taken out of the memory, and storing the processed data in the memory.

6. The safety control device for field source signal emission is designed, and can automatically adjust according to the ground resistance change between different emission electrodes, so that the emission current between different electrodes is always stabilized below the intrinsic safety current limit value.

Software layer:

1. by the mine electrical method multifunctional data acquisition and processing method, the electro-sectioning method data acquisition and the electro-fluoroscopy data acquisition are compatible, data acquisition of different methods is carried out in a time-sharing manner, richer observation data are obtained in a limited observation space, and the imaging resolution of an inversion result on the abnormal body space position and the spread range is improved; meanwhile, the method adopts a multi-frequency superposition method to process the pseudorandom multi-frequency signals, so that the broadband electromagnetic noise under the coal mine can be effectively suppressed, and the signal-to-noise ratio of the received signals is improved.

2. The quality control process for the underground direct current electrical method monitoring data is adopted, so that the real-time quality evaluation and control of the monitoring data are realized, and a reliable basis is provided for the subsequent electrical method monitoring data processing.

3. The correction of positive and negative attributes of the observed voltage breaks through the limitation that the observation range can only be limited to the region with the voltage as a positive value; the positive and negative attributes of the corrected voltage value and the actual voltage value are ensured to be consistent on the premise of not losing effective observation data, the detection resolution and the interpretation precision of the monitoring result can be improved, and the influence of system errors and the background environment is eliminated.

4. And the influence of electrode corrosion and polarization and shallow part nonuniformity on the observed data is eliminated through polarization effect correction and electrode consistency correction.

5. And a mixed weight constraint inversion method is adopted to carry out inversion imaging on the monitoring data, so that the imaging resolution ratio of the water damage hidden danger is improved.

6. By the integrated process method of detecting and monitoring the water disaster hidden danger of the mine by the electrical method, the water disaster hidden danger detection is firstly developed, the monitored key area is determined by the detection result, and meanwhile, a background reference model is established by the detection result to guide the geological interpretation of the monitoring result, so that the construction amount of underground operation can be reduced, and the interpretation precision of the monitoring result can be improved.

In conclusion, by the method, the influence of complex working condition environment under the coal mine on electric monitoring is overcome, the interpretation precision of the water disaster hidden danger of the mine is improved, the integrated process method of detecting and monitoring the water disaster hidden danger of the mine is further realized, and powerful technical support is provided for preventing and controlling the water disaster of the coal mine.

Drawings

FIG. 1 is a schematic diagram of an electrical method monitoring system for mine water damage hidden danger according to the invention;

FIG. 2 is an inverted imaging result of observation data obtained by an observation system formed by two linear survey lines;

FIG. 3 is an inversion imaging result of observation data obtained by the electrical monitoring system for the water damage hidden danger of the mine;

FIG. 4 is a schematic view of an electrical monitoring substation;

FIG. 5 is a schematic diagram of the components of the field source signal emitting device;

fig. 6 is a schematic circuit diagram of the field source signal transmitting apparatus;

FIG. 7 is a schematic diagram of the components of the signal acquisition device;

FIG. 8 is a schematic diagram of the components of a safety control device for field source signal transmission;

FIG. 9 is an emission current of all raw data in a single set of monitored data in an embodiment;

FIG. 10 is a signal-to-noise ratio of original data in a single set of monitored data processed in step 1 according to an embodiment;

FIG. 11 is a graph showing the potential difference of the original data in the single set of monitored data processed in step 2;

FIG. 12 is the potential difference of the partial measuring points after the processing of step 3 and step 4 in the embodiment;

fig. 13 is a graph of monitoring data before (upper) and after (lower) quality control in the example;

FIG. 14 is an inverted imaging result with uncorrected subsequent monitoring data for basin physical simulation;

FIG. 15 is an inversion imaging result of observed voltage positive and negative attribute correction for subsequent monitoring data of physical simulation of a water tank using the positional relationship of the transmitting and receiving measuring points;

FIG. 16 is an inversion imaging result of the water tank physical simulation subsequent monitoring data corrected by the positive and negative attributes of the observed voltage using the background subtraction method;

FIG. 17 is a plot of measured downhole data;

FIG. 18 is a graph of data after power supply electrode polarization effect correction is completed;

fig. 19 is a convergence curve of the inversion algorithm when different weights are applied when h =0 m;

fig. 20 is an inversion imaging result when h =0m without prior information constraint;

fig. 21 is the inversion imaging results when the monitor point weights are applied when h =0 m;

fig. 22 is the inversion imaging results when depth weights are applied for h =0 m;

fig. 23 is the inversion imaging results when the mixing weights are applied when h =0 m;

fig. 24 is an inversion imaging result when no prior information constraint is applied when h =20 m;

fig. 25 is the inversion imaging results when the monitor point weights are applied for h =20 m;

fig. 26 is the inversion imaging results when depth weights are applied for h =20 m;

fig. 27 is the inversion imaging results when the mixing weights are applied at h =20 m.

The reference symbols in the drawings mean:

1-a first electrical method monitoring substation, 2-a second electrical method monitoring substation, 3-a first 'L-shaped' measuring line, 4-a second 'L-shaped' measuring line, 5-an electrical method monitoring system controller, 6-a memory, 7-an electrical method monitoring data processor, 8-a substation controller, 9-a communication module, 10-an embedded central control module, 11-an infinite control relay, 12-a field source signal transmitting device, 13-a switch matrix module, 14-a signal acquisition device, 15-a network communication module, 16-a multichannel low noise isolation power supply module, 17-a boost DC-DC module, 18-a signal isolator, 19-a full bridge conversion circuit, 20-a first-stage filter amplification module, 21-a power frequency filter module, 22-a second-stage amplification module, 23-an optical coupling isolation module, 24-an AD acquisition module, 25-a stepper motor driver, 26-a stepper motor, 27-an adjustable sliding rheostat, 28-a MOSFET disk switch and 29-a sampling resistor.

Detailed Description

The technical contents of the present invention will be further described in detail with reference to the accompanying drawings and detailed description.

As shown in fig. 1, the core components of the electrical monitoring system for the hidden danger of mine water damage provided by the invention at least comprise:

and the electrical method monitoring system controller 5 is used for sending a control instruction to the first electrical method monitoring substation 1 and the second electrical method monitoring substation 2 according to a set electrical method monitoring scheme to acquire electrical method monitoring data.

The first L-shaped measuring line 3 and the second L-shaped measuring line 4 are respectively connected with a monitoring electrode group consisting of 4-32 monitoring electrodes and used for enclosing a rectangle to enclose a working surface, and the monitoring electrodes in the monitoring electrode group are used for transmitting signals and receiving signals.

The first electrical method monitoring substation 1 and the second electrical method monitoring substation 2 are respectively connected with the first L-shaped measuring line 3 and the second L-shaped measuring line 4 and used for receiving a control instruction of an electrical method monitoring system controller 5, switching the monitoring electrodes according to the control instruction to obtain a combination of the transmitting electrodes and the receiving electrodes and controlling signal transmitting and receiving and electrical method monitoring data acquisition.

The memory is used for storing, processing and quality control the electric method monitoring data acquired by the first electric method monitoring substation 1 and the second electric method monitoring substation 2; and is used for storing the data processed by the electrical method monitoring data processor.

And the electrical method monitoring data processor is used for accessing the memory, performing observation voltage positive and negative attribute correction, electrode polarization effect correction, electrode consistency correction and mixed weight constraint inversion imaging on the electrical method monitoring data taken out of the memory, and storing the processed data into the memory.

1. Mine water disaster hidden danger electrical method monitoring system hardware part

The hardware part of the invention is illustrated from 7 aspects as follows:

1. controller for electric monitoring system

The electrical monitoring system controller 5 is a ground server, is a core component of the present invention, and is connected to the first monitoring substation 1 and the second monitoring substation 2 through an optical fiber or a network cable, so as to implement network communication of a TCP/IP protocol. The electric method monitoring system controller 5 remotely controls the two electric method monitoring substations to carry out data acquisition processes by installing electric method acquisition device control software.

And the electrical method acquisition device control software installed on the electrical method monitoring system controller 5 is used for controlling the first electrical method monitoring substation 1 and the second electrical method monitoring substation 2 to execute monitoring data acquisition instructions according to a set monitoring mode. The control software of the electrical method acquisition device is realized by adopting a software development mode programming based on a BS framework.

2. About a first "L-shaped" measuring line 3 and a second "L-shaped" measuring line 4

The first L-shaped measuring line 3 and the second L-shaped measuring line 4 are arranged along a roadway around the working face and enclose a rectangle to enclose the working face; 32 monitoring electrodes are respectively connected to the first L-shaped measuring line 3 and the second L-shaped measuring line 4 according to the requirement of electric monitoring, and the distance between the monitoring electrodes is selected according to the field condition and the target monitoring precision and is 1-30 meters (preferably 20 meters). The monitoring electrodes are made of copper bars or stainless steel, and all the monitoring electrodes are buried in the bottom plate or the top plate of the coal seam. When the monitoring electrode is embedded into the bottom plate, the monitoring of the pressure-bearing water damage of the bottom plate can be realized; when the monitoring electrode is buried in the top plate, the monitoring of the water damage of the top plate can be realized.

The first L-shaped measuring line 3 and the second L-shaped measuring line 4 both adopt 32-core copper core explosion-proof cables, taps are manufactured at fixed track spacing, and monitoring electrodes are connected to the taps.

In the invention, the inversion imaging result of the observation data obtained by the observation system formed by two common linear measuring lines is compared with the observation system formed by two common linear measuring lines. Fig. 2 is an inversion imaging result of observation data obtained by an observation system formed by two linear survey lines, wherein the survey lines are arranged along the X direction, and it can be seen from the figure that a strip-shaped anomaly occurs in the direction perpendicular to the survey lines, and a false anomaly also exists near the survey lines. Fig. 3 is an inversion imaging result of observation data obtained by a "double L-shaped" full-enclosure array observation system formed by two "L-shaped" measuring lines of the present invention, and it can be seen from the figure that the low-resistance area spread range is better matched with the range of the abnormal body.

Compared with a conventional observation system formed by two linear measuring lines along the working face, the observation data along the working face trend are added, and the space density of the observation data is greatly improved on the premise of not increasing the use cost of equipment. When the system is used for acquiring the electrical data, observation data of an electro-sectioning method and observation data of an electro-fluoroscopy method can be acquired simultaneously, compared with a single observation method, more abundant observation data are further acquired by using a limited observation space, the data volume of single group of observation data is greatly improved, the data contains more abundant geological information, and a data base is laid for improving inversion imaging resolution and monitoring result interpretation precision.

3. First electric method monitoring substation 1 and second electric method monitoring substation 2

The first electric-method monitoring substation 1 and the second electric-method monitoring substation 2 adopt the same structure. The first electric-method monitoring substation 1 and the second electric-method monitoring substation 2 are both installed outside a working face and close to one end of a stoping line, and are connected to an underground power grid and a looped network. As shown in fig. 4, each electrical method monitoring substation at least includes a substation controller 8, a communication module 9, an embedded central control module 10, an infinity control relay 11, a field source signal transmitting device 12, a switch matrix module 13, a signal collecting device 14, a network communication module 15, and a multi-path low-noise isolation power supply module 16. The substation controller 8 is connected with the electrical monitoring system controller 5 and the signal acquisition device 14, and is connected with the embedded central control module 10 through the communication module 9; the embedded central control module 10 is respectively connected with the infinity control relay 11, the field source signal transmitting device 12 and the switch matrix module 13; the switch matrix module 13 is further connected to the field source signal emitting device 12, the signal collecting device 14 and the monitoring electrode set, respectively.

The network communication module 15 is composed of a 10/100M PHY ethernet transceiver DP83848KSQ and its peripheral circuits, and is used to implement the TCP/IP network communication function between the substation controller 8 and the electrical monitoring system controller 5. The corresponding TCP/IP network communication function of the electric method monitoring substation and the electric method monitoring system controller 5 is realized.

The substation controller 8 is used for receiving a control instruction issued by the electrical method monitoring system controller 5 through the network communication module 15, controlling the embedded central control module 10 to realize switching of monitoring electrodes, control signal transmission and signal reception, and controlling the signal acquisition device 14 to acquire electrical method signals;

and the communication module 9 is used for realizing the communication between the substation controller 8 and the embedded central control module 10.

The embedded central control module 10 is used for generating control logic signals of the infinite control relay 11, the field source signal transmitting device 12 and the switch matrix module 13 according to a control instruction of the substation controller 8;

and an infinity control relay 11 for connecting an infinity electrode to an output terminal of the field source signal transmitting device 12 or an input terminal of the signal collecting device 14 through the switch matrix module 13 according to the control logic signal transmitted from the embedded central control module 10 when the monopole transmission or the monopole reception is adopted.

And the field source signal transmitting device 12 is used for receiving the control logic signal transmitted by the embedded central control module 8 and converting the control logic signal into a high-voltage alternating-current square wave field source output signal to be transmitted.

The switch matrix module 13 is used for gating one or two monitoring electrodes in the monitoring electrode group to be correspondingly connected with the output terminal of the field source signal transmitting device 12 according to the control logic signal generated by the embedded central control module 10, and taking the selected monitoring electrodes as transmitting electrodes to form a transmitting channel; one or two of the rest electrodes in the gating monitoring electrode group are correspondingly connected with the input terminal of the signal acquisition device 14, and the selected monitoring electrode is used as a receiving electrode to form a receiving channel.

And the signal acquisition device 14 is used for acquiring electrical monitoring data according to the control instruction of the substation controller 8.

And the multi-path low-noise isolation power supply module 16 is used as a power supply of the electrical monitoring substation.

In a specific implementation process, the design of each part is as follows:

the embedded central control module 10 is an EMB8610I embedded industrial control module produced by embedded clouds in beijing. And controlling the relay 11 at infinity, and selecting a 100-1-C-5D single-pole single-set relay produced by Pickering.

The field source signal transmitting device 12 is shown in fig. 5, and includes a boost DC-DC module 17, a signal isolator 18 and a full bridge conversion circuit 19; the boost DC-DC module 17 and the signal isolator 18 are respectively connected with a full-bridge conversion circuit 19, and the signal isolator 18 is connected with the embedded central control module 10; the output terminal a and the output terminal B of the full-bridge conversion circuit 19 are used to connect one or a pair of electrodes (one selected for the monopole transmission mode and two selected for the dipole transmission mode) gated by the switch matrix module 13, which serve as transmission electrodes for transmitting signals from the electric field source. As shown in fig. 6, it is a schematic circuit diagram of the field source signal transmitter 12, wherein the step-up DC-DC module 17 is an HZD10C-07S100 DC-DC converter manufactured by beijing shogaku power source technologies ltd, which is used to convert a 4V-10V DC input into a maximum 100V/100mA DC output. The signal isolator 18 is a MAX22517 dual-channel digital isolator manufactured by Maxim Integrated, and is used to isolate the control logic signals F1 and F2 generated by the embedded central control module 10 from the control logic signals of the full-bridge conversion circuit 19. The full-bridge inverter circuit 19 selects an MTI85W100GC three-phase full-bridge inverter produced by IXYS corporation, and converts the 100V/100mA direct current output of the DC-DC converter into a square wave field source signal output of alternating current 100V/100mA through four internal MOSFETs under the action of control logic signals. The 1 terminal 1N1F of the device P3 (i.e. the signal isolator 18) is connected with a logic control signal F1 from the embedded central control module 10, the 2 terminal 1N2F is connected with a logic control signal F2 from the embedded central control module 10, the 3 and 4 terminals are connected with a 3.3V power supply and a power ground thereof, the 5 terminal is connected with an output ground terminal of the DC-DC converter P1, the 6 terminal is connected with an input 5V power supply terminal 2 of the DC-DC converter, the 7 terminal is connected with G2 and G3 terminals of the device P2 (i.e. the full-bridge conversion circuit 19), and the 8 terminal is connected with G1 and G4 terminals of the device P2. The S1, S2, S3, S4 terminals of the device P2 are connected with the output ground terminal 5 of the device P1 (i.e. the boost DC-DC module 17), the L + terminal is connected with the 4 terminal of the device P1, the L-terminal is connected with the 5 terminal of the device P1, the L1 terminal is the output terminal A, and the L2 terminal is the output terminal B. The 3 terminal of the device P1 is a null terminal and is not connected to any circuit. In the above technical solution, the control logic signals F1 and F2 from the embedded central control module 10 are square wave signals with opposite phases, and when F1 is high level and F2 is low level, the current direction of the high-voltage output of the DC-DC converter flows from the output terminal a to the output terminal B; when the F1 is low level and the F2 is high level, the current direction of the DC-DC high voltage output is that the output terminal B flows to the output terminal a, so that the control logic signal from the embedded central control module 10 is converted into the square wave field source signal of alternating high voltage on the transmitting electrode a and the transmitting electrode B to be output.

The switch matrix module 13 is a 32x4 medium density matrix switch module produced by Pickering company, and can realize any 32-to-4 logic switch.

The signal acquisition device 14, the structure of which is shown in fig. 7, includes a primary filtering and amplifying module 20, a power frequency filtering module 21, a secondary amplifying module 22, an optical coupling isolation module 23, and an AD acquisition module 24. The signal input end of the first-stage filtering and amplifying module 20 is used as the signal input end of the signal acquisition device 14, the input terminal M and the input terminal N thereof are used for connecting one or two receiving electrodes (one is selected for the monopole receiving mode and two are selected for the dipole receiving mode) selected by the switch matrix module 13 in the monitoring electrode group, and the output end thereof is connected with the signal input end of the power frequency filtering module 21; the signal output end of the power frequency filtering module 21 is connected with the signal input end of the secondary amplification module 22; the signal output end of the secondary amplification module 22 is connected with the signal input end of the AD acquisition module 24; the substation controller 8 is respectively connected with the amplification factor control pins of the primary filtering amplification module 20 and the secondary amplification module 22 through an optical coupling isolation module 23; the substation controller 8 is also connected to the control end and the data output end of the AD acquisition module 24, respectively. Specifically, the first-stage filtering and amplifying module 20 is used as a signal input end of the signal acquisition device 14, is used for primary filtering and signal amplification of electrical monitoring signals, and is composed of an AD8251 program-controlled instrument amplifier and a peripheral circuit thereof, wherein a low-pass filter is arranged in front of the signal input end through a resistor-capacitor, the cut-off frequency is 10KHz, and the selectable amplification factor of the amplifier is 1,2, 4 or 8. The power frequency filtering module 21 is a post-stage circuit of the first-stage filtering amplifying module 20, is used for suppressing a 50Hz power frequency interference signal, and consists of a universal active filter UAF42 and a peripheral circuit thereof, and a second-order Butterworth wave trap is configured on the universal active filter UAF and the peripheral circuit thereof, so that a filtering function of a high Q value of a target frequency point is realized. And the secondary amplification module 22 consists of a program control instrument amplifier PGA205 and a peripheral circuit thereof, and is used for amplifying the monitoring signals passing through the primary filtering amplification module 20 and the power frequency filtering module 21 again, wherein the amplification times can be selected from 1,2, 4 and 8 times. The optical coupling isolation module 23 is composed of a TLP521-4 optical coupling isolator and peripheral circuits thereof, and is used for signal isolation communication between devices with different levels, power supply levels of amplifier amplification factor selection pins of the primary filtering amplification module 20 and the secondary amplification module 22 are +/-7V, power supply levels of control IO pins of the substation controller 8 are 3.3V, and signal communication between the substation controller 8 and the primary filtering amplification module 20 and the secondary amplification module 22 is achieved through the optical coupling isolation module 23. And the AD acquisition module 24 consists of an AD1262IPW and peripheral circuits thereof, and a signal input end of the AD acquisition module is an output end of the secondary amplification module 22, so as to realize analog-to-digital conversion and data acquisition of electrical monitoring signals entering from the two input terminals after passing through the primary filtering amplification module 20, the power frequency filtering module 21 and the secondary amplification module 22. When the data acquisition of the electro-sectioning method is carried out: adopting a rising edge and a falling edge of a signal in one period of a transmitted square wave signal as trigger signals for starting acquisition of an AD chip, and synchronously acquiring response signals on a receiving electrode; at the moment, the sampling frequency of the AD data is set to be 50Hz, and under the data rate, an internal digital filter of the AD chip can be configured to further filter 50Hz interference signals, so that the rejection ratio can reach-100 dB, and the power frequency interference is almost completely filtered. When the data acquisition of the electric perspective method is carried out: the signal acquisition is not synchronous to trigger the signal, produce and start the acquisition signal by the substation controller 8, the AD data sampling frequency can be configured to 1200Hz, 2400Hz, 4800Hz, 7200Hz and 14400Hz at this moment, match and select according to different transmission field source signal frequency and data quality.

The multi-path low-noise isolation power supply module 16 selects a KDY127-12 (A) mining explosion-proof and intrinsic safety type direct current power supply which is produced by the MiddleCardiology, seisan research institute (group) limited company, and an explosion-proof certificate CCCMT22.0958 as a power supply, and the power supply is connected to an underground industrial power grid to supply power to the whole device, so that mutually independent power supply input with low ripple noise is provided, and the weak signal acquisition performance of the multifunctional data acquisition device of the mine electrical method is ensured. Specifically, the power supply scheme for each module is as follows: the primary filtering and amplifying module 20, the power frequency filtering module 21 and the secondary amplifying module 22 are analog signal processing parts, and a +/-9V power supply is supplied to the analog signal processing parts; the switch matrix module 13, the substation controller 8, the optical coupling isolation module 23, the network communication module 15, the embedded central control module 10 and the communication module 9 are digital signal control parts and are supplied with a +5V power supply; the AD acquisition module 24 is an analog and digital hybrid module, and supplies ± 9V to it as a driving power supply and a +5V power supply as a reference power supply. The +/-9V power supply and the 5V power supply are isolated, the power frequency withstand voltage of 500V and 1min can be borne, and the leakage current is not more than 5mA.

The electric method monitoring system controller 5 sends acquisition instructions to the first electric method monitoring substation 1 and the second electric method monitoring substation 2 according to a set monitoring mode to control the working states of the first electric method monitoring substation and the second electric method monitoring substation, the two electric method monitoring substations are matched to execute monitoring data acquisition instructions to respectively acquire electric sectioning method observation data and electric perspective method observation data, and the electric sectioning method observation data and the electric perspective method observation data jointly form complete monitoring data. Specifically, the invention provides a control method of an electrical monitoring system controller, which comprises the following specific processes:

step 1: numbering the monitoring electrodes: number of monitoring electrodes in monitoring electrode group on first L-shaped measuring line 3i ₁ ＝1,2,……,N ₁ (ii) a Number of monitoring electrode in monitoring electrode group of second L-shaped measuring line 4i ₂ ＝N ₁ +1, N ₁ +2, ……, N ₁ +N ₂ Wherein N is ₁ 、N ₂ The number of monitoring electrodes on the first L-shaped measuring line 3 and the second L-shaped measuring line 4 respectively.

Step 2: according to a control instruction of the electrical monitoring system controller 5, executing the step 3 to acquire electrical profile data; step 4 is performed to acquire the electrical fluoroscopy data. The electrical profile data and the electrical fluoroscopy data are collected separately here in order to avoid signal interference with each other.

And step 3: collecting electrical profile data: setting the monitoring substations into an electrical profile working mode, and controlling the two monitoring substations to alternately carry out monitoring data acquisition in a self-sending and self-receiving mode; in the electrical profile working mode, the monitoring substation starts the transmitting and receiving functions at the same time; when the monitoring substation carries out data acquisition, corresponding transmitting electrodes and receiving electrodes are switched according to an electrode alternation sequence, direct-current square wave signals are transmitted and received, square wave amplitudes are read and returned, and the square wave amplitudes (namely the direct-current square wave signals) are stored in a memory in real time; the transmitting electrode and the receiving electrode are located on the same measuring line.

The method specifically comprises the following steps:

step 31, the second electrical monitoring substation 2 is standby, the substation controller 8 of the first electrical monitoring substation 1 issues a control instruction, the embedded central control module 10 operates the infinity control relay 11, the field source signal emission device 12 and the switch matrix module 13 according to the control instruction, and switches the monitoring electrodes on the first L-shaped measurement line 3 to select the emission electrodes, specifically from No. 1 to N ₁ The number is switched by 1 or 2 in turn (the number of monopole transmission modes is 1, and the number of dipole transmission modes is 2); the selected transmitting electrode continuously transmits a direct-current square wave signal every time, in the transmitting process, monitoring electrodes except the current transmitting electrode on the first L-shaped measuring line 3 are switched to select receiving electrodes, specifically, 1 or 2 monitoring electrodes are sequentially switched from front to back according to serial numbers (a single-pole receiving mode needs 1, a dipole receiving mode needs 2), the selected receiving electrodes receive signals every time, and the received signals are processed and acquired through the signal acquisition device 14; thereby obtaining the electrical profile data collected by the first electrical method monitoring substation 1;

step 32, the first electrical monitoring substation 1 is standby, the substation controller 8 of the second electrical monitoring substation 2 issues a control instruction, the embedded central control module 10 operates the infinity control relay 11, the field source signal transmitting device 12 and the switch matrix module 13 according to the control instruction, the monitoring electrodes on the second L-shaped measuring line 4 are switched to select transmitting electrodes, and particularly, the transmitting electrodes are selected from N ₁ +1 starts moving backwards to N ₁ + N ₂ The numbers are sequentially switched by 1 or 2; the selected transmitting electrode continuously transmits a direct-current square wave signal every time, in the transmitting process, monitoring electrodes except the transmitting electrode on the second L-shaped measuring line 4 are switched to select receiving electrodes, and specifically, 1 or 2 receiving electrodes are sequentially switched from front to back according to serial numbers; each time the selected receiving electrode receives signals, the received signals are processed and collected through the signal collecting device 14; thereby obtaining the electrical profile data collected by the second electrical method monitoring substation 2; the operation in which the monitor electrodes are switched to select the transmitting electrode and the receiving electrode is the same as described above. Obtaining a set of electrical profile data for the first electrical method monitoring substation 1 and the second electrical method monitoring substation 2 therefrom;

and 4, step 4: acquiring perspective data: setting the monitoring substations into an electric perspective working mode, namely controlling the two monitoring substations to adopt a mode of mutual transmission and mutual reception for monitoring data acquisition; in the electric perspective working mode, two monitoring substations are matched to carry out data acquisition, one monitoring substation is used as a transmitter, and the other monitoring substation is used as a receiver; the monitoring electrodes connected with the transmitter are all used as transmitting electrodes, and the monitoring electrodes connected with the receiver are all used as measuring electrode receiving electrodes; the transmitting electrode transmits a pseudo-random multi-frequency wave signal, the receiving electrode receives a full-waveform signal (namely multi-frequency data), and the full-waveform data is stored in the memory in real time.

The method specifically comprises the following sub-processes:

step 41, the substation controller 8 of the first electrical method monitoring substation 1 issues a control instruction, the embedded central control module 10 operates the infinity control relay 11, the field source signal transmitting device 12 and the switch matrix module 13 according to the control instruction, and switches the monitoring electrodes on the first L-shaped measuring line 3 in the first electrical method monitoring substation 1Selecting emitter electrodes, in particular from No. 1 to N ₁ The numbers are sequentially switched by 1 or 2; the method comprises the following steps that a selected transmitting electrode continuously transmits a pseudorandom multi-frequency signal every time, in the transmitting process, a substation controller 8 of a second electrical monitoring substation 2 issues a control instruction, an embedded central control module 10 operates an infinite control relay 11, a field source signal transmitting device 12 and a switch matrix module 13 according to the control instruction, monitoring electrodes on a second L-shaped measuring line 4 in the second electrical monitoring substation 2 are switched to select receiving electrodes, specifically, 1 or 2 receiving electrodes are sequentially switched from front to back according to serial numbers, the selected receiving electrodes receive signals every time, and the received signals are processed and collected through a signal collecting device 14; obtaining electric perspective data collected by the second electric-method monitoring substation 2;

step 42, switching the monitoring electrode on the second L-shaped measuring line 4 in the second electrical method monitoring substation 2 to select the transmitting electrode, specifically from N ₁ Number to N ₁ + N ₂ The numbers are sequentially switched by 1 or 2; the selected transmitting electrodes continuously transmit pseudo-random multi-frequency signals each time, in the transmitting process, all monitoring electrodes on a first L-shaped measuring line 3 in the first electric-method monitoring substation 1 are switched to select receiving electrodes, specifically, 1 or 2 monitoring electrodes are sequentially switched from front to back according to serial numbers, the selected receiving electrodes receive signals each time, and the received signals are processed and acquired through the signal acquisition device 14; obtaining electric perspective data collected by a first electric method monitoring substation 1; obtaining a set of electrical perspective data of the first electrical monitoring substation 1 and the second electrical monitoring substation 2;

specifically, in the process of collecting electrical section and electrical perspective data, three working modes can be adopted for monitoring electrode switching: monopole-monopole mode of operation, monopole-dipole mode of operation, dipole-dipole mode of operation.

In the

above steps

3 and 4, according to different working modes, the operations of switching the monitoring electrode to select the transmitting electrode are respectively as follows:

monopole emission mode: controlling an infinite control relay 11 corresponding to the electric monitoring substation to connect an output terminal B of a field source signal transmitting device 12 into an infinite electrode; the control switch matrix module 13 connects the output terminal a of the field source signal transmitting device 12 to a selected one of the transmitting electrodes.

Dipole transmission mode: controlling a switch matrix module 13 corresponding to the electric monitoring substation to connect the selected two transmitting electrodes into an output terminal A and an output terminal B of the field source signal transmitting device 12;

specifically, in the

above steps

3 and 4, the operations of switching the monitoring electrode to select the receiving electrode according to different working modes are respectively as follows:

monopole reception mode: controlling an infinite control relay 11 corresponding to the electric monitoring substation, and connecting an input terminal N of a functional data acquisition module 12 into an infinite electrode; the switch matrix module 13 is operated to connect the input terminal M of the signal acquisition device 14 to a selected one of the receiving electrodes;

dipole reception mode: and controlling a switch matrix module 13 of the corresponding electrical monitoring substation to connect two selected receiving electrodes in the monitoring electrode group into an input terminal M and an input terminal N of a signal acquisition device 14.

Under the monopole-monopole working mode, switching into a monopole transmitting mode and a monopole receiving mode; under the monopole-dipole working mode, switching into a monopole transmitting mode and a dipole receiving mode; and under the dipole-dipole working mode, the dipole transmitting mode and the dipole receiving mode are switched.

When the electrical section and the electrical perspective data acquisition are carried out, the working mode of monitoring electrode switching must be kept consistent.

And 5: and the first electrical method monitoring substation 1 and the second electrical method monitoring substation 2 continuously receive the acquisition instruction sent by the electrical method monitoring system controller 5, circularly execute the step 3 to the step 4 to obtain multiple groups of required electrical profile data and electrical perspective data, and store the obtained data in a memory.

In the technical scheme, the electric field source signal transmitting electrode and the receiving electrode can be selected from all monitoring electrodes on an L-shaped measuring line, so that the electric monitoring can be flexibly designed in a monitoring scheme, and the transmission step distance, the transmitting pole distance, the receiving step distance and the receiving pole distance can be flexibly adjusted by similarly expanding; it is worth to be noted that, when the prior art scheme carries out electrical method monitoring, a potential acquisition mode is usually adopted, the potential difference between two points is obtained by calculating the difference, and the signal to noise ratio is lower, but the method realizes real acquisition of the potential difference between the electrodes by freely selecting an acquisition channel, and obviously improves the signal to noise ratio of weak effective signals; it is worth to be noted that the monitoring electrodes can be infinitely expanded in a software control mode, so that the cooperative work of a plurality of monitoring substations can be realized, and the control of a more complex electrode array can be carried out; it should be noted that different working modes have different signal strengths and resolutions, the monopole-monopole working mode has the maximum signal strength and the worst resolution, the dipole-dipole working mode has the weakest signal strength and the highest resolution, and the monopole-dipole working mode has the signal strength and the resolution between the two, so that when monitoring data acquisition is performed, a working mode with higher resolution needs to be adopted on the premise of ensuring the signal strength.

4. About memory

The memory is used for processing the acquired original signals (electrical monitoring data), performing quality control and storing various data generated in the monitoring process.

The memory consists of a database, a direct current square wave signal processing module, a multi-frequency data processing module and a monitoring data quality control module. The database is developed by adopting SQLServer or MySQL; the direct-current square wave signal processing module, the multi-frequency data processing module and the electrical method monitoring data quality control module are realized by Matlab language programming, and a dynamic link library is generated for calling a memory. The memory stores various data generated in the monitoring process in a database mode, wherein the data comprises working face information, monitoring substation information, monitoring electrode coordinates, acquisition parameters, original waveform data, data generated after signal processing and data processing and the like; the memory processes the acquired original signals through a direct-current square wave signal processing module and a multi-frequency data processing module which are monitored by an electrical method; the memory carries out quality control on the electrical method monitoring data through a quality control module of the electrical method monitoring data. The electric method monitoring system controller, the first electric method monitoring substation, the second electric method monitoring substation and the electric method monitoring data processor are used for data interaction by accessing the database.

The memory workflow is as follows:

the method comprises the following steps: and establishing a database in a memory, and predefining table structures of various data, including a working face information table, a monitoring substation information table, a monitoring electrode information table, an acquisition mode parameter table, a monitoring log table, a monitoring data processing result table and the like.

Step two: initializing (working face information, monitoring substation information, monitoring electrode information, acquisition mode parameters and the like) through an electrical monitoring system controller, and storing the initialization information into a corresponding table of a database;

step three: the electric method monitoring system controller accesses the database, acquires acquisition mode parameters, sends acquisition instructions to the first electric method monitoring substation and the second electric method monitoring substation according to the acquisition mode parameter setting, and the electric method monitoring substations acquire monitoring data according to the acquisition instructions;

step four: when monitoring data are collected by the first electric-method monitoring substation and the second electric-method monitoring substation, the collected original signals are transmitted in real time and stored in a database;

step five: under the working mode of the electrical profile, the memorizer carries out corresponding signal processing on square wave signal amplitudes acquired by a first electrical method monitoring substation and a second electrical method monitoring substation by using a direct current square wave signal processing method, and processing results are stored in a database in real time;

step six: under the electric perspective working mode, the memory carries out corresponding signal processing on original full-waveform signals acquired by the first electric-method monitoring substation and the second electric-method monitoring substation by using a multi-frequency data processing method, and processing results are stored in a database in real time;

step seven: the memory carries out quality evaluation and control on a group of complete original monitoring data through a quality control process of the electrical monitoring data, screens and marks the monitoring data with qualified quality, marks the monitoring data with qualified quality as an unprocessed state, and stores a processing result into a database in real time;

step eight: the electrical method monitoring data processor accesses the database in real time, carries out preprocessing and inversion imaging on the monitoring data which are qualified in quality and marked as unprocessed states, stores the obtained results into the database in real time, and marks the group of monitoring data as processed states in the database.

5. Data processor for electrical monitoring

The electrical method monitoring data processor comprises key core modules such as an observation voltage positive and negative attribute correction module, an electrode polarization effect correction module, an electrode consistency correction module and a mixed weight constraint inversion processing module. The electric method monitoring data processor eliminates the influence of acquisition errors and shallow unevenness of monitoring equipment by observing preprocessing methods such as a voltage positive and negative attribute correction module, an electrode polarization effect correction module and an electrode consistency correction module, and realizes high-resolution dynamic display of the water damage hidden danger development process by a mixed weight constraint inversion imaging module. The key core modules such as the observation voltage positive and negative attribute correction module, the electrode polarization effect correction module, the electrode consistency correction module, the mixed weight constraint inversion processing module and the like are realized by Matlab language programming, and a dynamic link library power supply method monitoring data processor is generated for calling. The electric method monitoring data processor is used for carrying out the preprocessing and the inversion imaging on the monitoring data marked in the memory and with qualified quality, and the subsequent data processing is not needed for the monitoring data with unqualified quality. The working flow of the electrical monitoring data processor is as follows:

the method comprises the following steps: configuring data preprocessing parameters and inversion parameters, wherein the data preprocessing parameters and the inversion parameters comprise data noise level, inversion grid parameters, inversion iteration times and a reference model, and the reference model is used for constraining prior information in the inversion process;

step two: the electrical monitoring data processor has two modes of manual operation and automatic operation; in a manual mode, a technician sets monitoring data needing to be processed and imaged, an electrical method monitoring data processor accesses a memory to acquire the set monitoring data needing to be processed and imaged, and preprocessing and inversion imaging are carried out; in an automatic operation mode, the electrical method monitoring data processor automatically accesses the memory at fixed time intervals, acquires the monitoring data marked as qualified and unprocessed, and executes the third and fourth steps of preprocessing and inversion imaging;

step three: preprocessing the monitoring data: firstly, correcting positive and negative attributes of monitoring data taken out from a memory by using an observation voltage positive and negative attribute correction module; correcting data abnormity caused by electrode polarization effect in the monitoring data by using an electrode polarization effect correction module; then, correcting the influence of electrode corrosion and shallow part nonuniformity in the monitoring data by using an electrode consistency correction module, and storing the data generated in the process into a memory;

step four: and performing inversion imaging on the preprocessed monitoring data by using a mixed weight constraint inversion processing module, and storing an imaging result into a memory.

Step five: and marking the monitoring data which completes the preprocessing and the inversion imaging as a processed state in the memory.

6. With respect to other general-purpose devices

The invention provides an electric monitoring system for mine water damage hidden danger, which also comprises a universal instrument. The electric monitoring controller 5 is also connected with a display to form a universal instrument; for enabling the display of documents, graphics, images, and the like; the display can also be connected with a communicator to realize screen sharing or remote monitoring.

The mine water damage hidden danger electrical monitoring system has the following advantages:

A. compared with a conventional observation system formed by two linear measuring lines along the direction of the working surface, the invention can simultaneously acquire observation data along the direction and the trend of the rectangular working surface, greatly improves the spatial density of the observation data on the premise of not increasing the use cost of equipment, and acquires richer observation data. Through comparison of the embodiment, strip-shaped abnormity appears in the vertical line measuring direction in a conventional mode, and false abnormity also exists near the measuring line; the low-resistance area spreading range of the invention is better matched with the range of the abnormal body.

B. The two monitoring substations are controlled by the controller 5 of the electrical method monitoring system together, the observation system can be used for collecting observation data of an electro-sectioning method and observation data of an electro-fluoroscopy method, compared with a single observation method, more abundant observation data are further obtained by using a limited observation space, the data volume of single group of observation data is greatly improved, more abundant geological information is contained in the data, and a data base is laid for improving inversion imaging resolution and monitoring result interpretation precision.

C. When the prior technical scheme carries out electrical monitoring, a potential acquisition mode is usually adopted, the potential difference between two points is obtained by calculating the difference, and the signal to noise ratio is lower.

D. The controller 5 of the electric monitoring system can also be expanded to realize the common control of more than two monitoring substations and is used for monitoring the water damage hidden danger of the coal face with the strike length of more than 600 m.

E. The acquired electrical monitoring data is stored in real time, processed by the signal processing and quality control device through the memory, and the data processed by the electrical monitoring data processor is stored in real time, so that the effectiveness of data in each link in the signal processing and data processing flows is guaranteed, and a foundation is laid for the automation of the data processing flows.

F. The electric monitoring data processor accesses the memory, performs observation voltage positive and negative attribute correction, electrode polarization effect correction, electrode consistency correction and mixed weight constraint inversion imaging on the electric monitoring data taken out of the memory, and stores the processed data into the memory, so that the full-flow real-time and automatic processing and storage of the monitoring data are realized, the workload of technical personnel in data processing is greatly reduced, the effectiveness of the monitoring system from data acquisition to monitoring result feedback to users is improved, and the purposes of people reduction and efficiency improvement are achieved.

7. Safety control device for field source signal transmission

In the field of electrical method monitoring, in order to meet the intrinsic safety requirement, the technical method generally adopted at present is that a field source transmitting part is set to be high-voltage and constant-voltage transmitting, the current value of a transmitting loop is detected after transmitting output is started, and when the detected current value exceeds the intrinsic safety current limit value, the transmitting loop is cut off through a comparison circuit and a switch circuit. However, when performing an electrical monitoring task, the field source signal needs to be switched between all monitoring electrodes, and since the monitoring period is long, the ground resistance difference between different field source transmitting electrodes is large and changes with time, in order to make the transmitting loop work normally, the prior art will connect an access resistor with a large and fixed resistance value in series between the transmitting output end and the transmitting electrode according to the pre-sampling test condition, so that the current value of the transmitting loop is always stabilized below the intrinsic safety current-limiting value. By adopting the mode of connecting the fixed resistance value into the resistor, the subjective influence of operators is large, and the automatic adjustment cannot be flexibly carried out according to the ground resistance change between different transmitting electrodes, so that the maximum power output under the intrinsic safety limit cannot be fully utilized, the energy of the monitored field source cannot be maximally loaded to the target monitoring geologic body to obtain the best possible field source response signal, the data acquisition quality is influenced, and the accuracy of inversion interpretation is influenced.

Based on this, the hardware part of the mine water damage hidden danger electrical method monitoring system of the present invention is further supplemented and improved, and a safety control device for field source signal transmission is designed, please refer to fig. 8, which includes a stepping motor driver 25, a stepping motor 26, a disk adjustable slide rheostat 27, a MOSFET switch 28 and a sampling resistor 29. Wherein, the stepping motor driver 25, the MOSFET switch 28 and the sampling resistor 29 are respectively connected with the embedded central control module 10; the stepping motor driver 25, the stepping motor 26 and the disc adjustable slide rheostat 27 are connected in sequence; the sampling resistor 29, the MOSFET switch 28, the switch matrix module 13, the disk adjustable slide rheostat 27 and the monitoring electrode group are sequentially connected end to form a transmitting loop.

In the technical scheme, the embedded central control module 10 is used for acquiring a voltage value of the sampling resistor 29, and further calculating a current between a certain pair of electrodes serving as an electric field source emission in the monitoring electrode group as an emission current value; the device is used for setting an intrinsic safety current limiting value, executing a PID (proportion integration differentiation) feedback algorithm to continuously compare a transmitting current value with the intrinsic safety current limiting value, generating a PWM (pulse width modulation) pulse control signal and a forward and reverse rotation direction signal required by a stepping motor driver 25 according to a comparison result, and driving a stepping motor 26 to adjust the resistance value of a disc adjustable slide rheostat 27 so as to change the resistance value of an access resistor between transmitting loops; for generating the control logic signals required by the field source signal emitting device 12, the switch matrix module 13 and the MOSFET switch 28, respectively.

The stepping motor driver 25 is used for converting the PWM pulse control signal sent by the embedded central control module 10 into a strong current signal required by the stepping motor 26 and driving the stepping motor 26 to operate; the stepping motor 26A is used for receiving forward and reverse rotation direction signals sent by the embedded central control module 10, wherein the forward rotation signals are high level, the reverse rotation signals are low level, and when the forward rotation signals are high level, the stepping motor 26A is controlled to be connected with VCC, the B pole is grounded, and the stepping motor rotates forward; when the voltage is low, the pole a of the reverse stepping motor 26 is grounded, and the pole B is grounded and is reversed.

The stepping motor 26 is an actuator of the stepping motor driver 25, and is used for driving the cantilever of the disc adjustable slide rheostat 27 to rotate under the driving of the stepping motor driver 25.

The disk adjustable slide rheostat 27 is an actuating mechanism of the stepping motor 26, and changes the resistance value thereof through the rotation of the cantilever as an access resistance in the transmitting loop. Considering the requirements that the apparent resistivity of the coal seam, the source voltage of the emission field, the current limiting value and the working power of the intrinsic safety device are not more than 2/3 of the rated power of the intrinsic safety device, the resistance value range R of the disc adjustable slide rheostat 27 is 1-2000 omega, and the power P is not less than 15W.

The MOSFET switch 28, which is an N-channel fet, is configured to cut off the transmission loop under special conditions such as failure of the disc adjustable sliding varistor 27, according to the control logic signal of the embedded central control module 10, i.e., the MOSFET gate control signal, thereby ensuring the intrinsic safety of the system of the present invention.

The sampling resistor 29 is a non-inductive precision resistor with 10 ohms and 1% and is used for converting a current value in the transmitting loop into a voltage value for the embedded central control module 10 to collect.

The safety control method for field source signal emission realized by the safety control device for field source signal emission specifically comprises the following steps:

the method comprises the following steps: the disc adjustable slide rheostat 27 is placed in an initial state (a state of maximum resistance). To ensure that the current value in the transmit loop is the smallest possible value.

Step two: setting voltage value U of field source emission signal _s And intrinsic safety current limiting value I _lim . For a clearer description of the implementation, the typical value U of the signal emitted by the intrinsic safety field source in electrical monitoring is used _s =100V，I _lim =60mA for example;

step three: setting the waveform and frequency of a field source transmitting signal according to the requirement of electrical monitoring;

step four: the embedded central control module 10 generates corresponding control signals to control the switch matrix module 13 to select one or a pair of electrodes in the monitoring electrode group, and the output terminal A and the output terminal B of the field source signal transmitting device 12 are correspondingly connected to be used as transmitting electrodes of field source signals;

step five: the field source signal transmitting device 12 starts a transmitting electrode to realize field source signal transmission according to a control signal generated by the embedded central control module 10; monitoring other electrodes in the electrode group to acquire electrical signal data;

step six: the embedded central control module 10 collects the voltage on the sampling resistor 29, calculates the voltage value Ur on the sampling resistor 29 in a signal amplification mode, and calculates the transmitting current value in the transmitting loop at the moment according to the voltage value Ur

Ur is in the unit V,10 is in the unit

，I _r The unit of (A);

step seven: the embedded central control module 10 will emit a current value I _r The intrinsic safety current limiting value I set in the step two _lim Comparing, if the emission current value I _r Less than intrinsic safety current limiting value I _lim Then the embedded central control module 10 sends to the stepper motor driver 25Sending PWM pulse control signal, the step motor driver 25 controls the step motor 26 according to the received signal, the step motor 26 drives the cantilever of the disk adjustable slide rheostat 27 to rotate anticlockwise, and the access resistance R in the transmitting loop is reduced _t (ii) a If the emission current value I _r Not less than intrinsic safety limiting value I _lim Executing the step ten;

step eight: returning to the step six, forming negative feedback type control logic until the transmitting current value I in the transmitting circuit _r Approximately equal to the intrinsic safety current limiting value I _lim Step nine is executed;

step nine: when the monitoring data acquisition is completed, the embedded central control module 10 controls the field source signal transmitting device 12 to stop the field source signal transmission of the current transmitting electrode, and meanwhile, the embedded central control module 10 generates a corresponding control signal to control the switch matrix module 13 to select another electrode or a pair of electrodes in the monitoring electrode group as the transmitting electrode of the field source signal and mark the transmitting electrode, and the fifth step is returned until all the electrodes in the monitoring electrodes 9 are marked, and the transmitting process is finished.

Step ten: the embedded central control module 10 sends a control logic signal to the MOSFET switch 28 to make the gate control signal of the MOSFET switch 28 low, and disconnects the drain and the source, i.e. cuts off the transmission loop, and then the embedded central control module 10 sends a PWM pulse control signal to the stepping motor driver 25 to control the stepping motor 26 to drive the cantilever of the disc adjustable slide rheostat 27 to rotate clockwise, so as to increase the access resistance R in the transmission loop _t Up to a value of the transmission current I in the transmission circuit _r Approximately equal to the intrinsic safety current limiting value I _lim And returning to the step nine.

The field source signal emission safety control device and method have the following beneficial effects:

(1) In the electric method monitoring process, the embedded central control module 10 calculates the current between field source transmitting electrodes through the sampling resistor 29, executes a PID feedback algorithm, controls the rotation angle of the stepping electrode and further adjusts the resistance value of a resistor between transmitting loops, so that the resistance value is continuously close to a set intrinsic safety current limiting value;

(2) When the field source emission electrode is switched in the electrical method monitoring process, the access resistance between different emission electrodes can be automatically adjusted, so that the emission current between different electrodes is always stabilized below the intrinsic safety current limiting value;

(3) In the long-term electrical method monitoring process, the emission current between the emission electrodes is not influenced by time and the change of the environment where the electrodes are positioned, so that the emission current is always stabilized below the intrinsic safety current limiting value;

(4) The maximum field source transmitting power under the intrinsic safety limiting condition can be fully utilized to obtain reliable received data, so that a credible inversion interpretation result is obtained, and the occurrence of water damage accidents is reduced;

(5) When the current value between the loops exceeds the set intrinsic safety current limiting value, the MOSFET switch 28 is switched off, namely, the transmitting loop is switched off, namely, the MOSFET switch 28 can be used as a first-level intrinsic safety protection circuit; the disc adjustable sliding rheostat 27 is in a maximum resistance value state in an initial state, the current value of the transmitting loop is limited to be not larger than the intrinsic safety current value, and the variable access resistor can serve as another level of intrinsic safety protection circuit. When any one of the intrinsic safety protection currents is used as a fault counting point (namely, the device fails), ignition of a spark ignition test cannot be caused, namely, a two-pole intrinsic safety protection circuit is provided, so that the device principle meets the requirement of an intrinsic safety circuit of electrical equipment of 'ib' grade in GB 3836.4-2021.

The mine water damage hidden danger electrical monitoring system is used for detecting and monitoring the water damage hidden danger through a mine water damage hidden danger electrical detection and monitoring integrated process method, and specifically comprises the following steps:

the method comprises the following steps: system installation: after the roadway of the working face is formed and before stoping is not started, a first L-shaped measuring line 3 and a second L-shaped measuring line 4 are arranged along the roadway around the working face to form a double-L-shaped full-surrounding array; in the installation process, proper protection measures are adopted to avoid the monitoring cables and the electrodes from being damaged after entering the goaf; the method comprises the following steps that a double-L-shaped full-surrounding array is connected into a first electric method monitoring substation 1 and a second electric method monitoring substation 2, the two electric method monitoring substations are arranged at one end, close to a stop production line, outside a working face, and are connected into an underground power grid and a ring network nearby; the electric method monitoring system controller, the memory and the electric method monitoring data processor are connected and installed on the electric method monitoring system controller; the two electric method monitoring substations are connected to an electric method monitoring system controller through a network; the electrical method monitoring system controller, the memory and the electrical method monitoring data processor carry out data interaction through a memory database interface; and performing combined debugging on the ground and the underground monitoring system to ensure the normal operation of each module of the system.

Step two: information initialization: the information is initialized by an electrical monitoring system controller, and the initialized information is stored in corresponding tables of a database of a memory, wherein the tables comprise a working face information table, a monitoring substation information table, a monitoring electrode information table, a monitoring mode parameter table and the like.

Step three: monitoring signal emission and collection: the ground electric method monitoring system controller sends transmitting and collecting instructions to the electric method monitoring substations according to the monitoring mode setting, and controls the working states of the two electric method monitoring substations; the two electric-method monitoring substations are matched to execute monitoring signal transmitting and collecting instructions, the double-L-shaped full-surrounding array is used for realizing the transmitting and collecting of the monitoring signals, and the observation data collection and storage of the electric sectioning method and the electric perspective method are respectively completed.

Step four: signal processing: in the process of monitoring data acquisition, a memory is utilized to carry out real-time signal processing on the acquired original signals; under the working mode of the electrical section, the acquired direct-current square wave signals are processed in real time, and the converted observation voltage is stored in a database of a memory in real time; and under the electric perspective working mode, the acquired pseudo-random multi-frequency signals are processed in real time, electromagnetic noise interference in the pseudo-random multi-frequency signals is suppressed, and the converted observation voltage is stored in a database in real time.

Step five: and (3) cyclic monitoring: and after the acquisition of one group of complete monitoring data is completed, the controller of the electrical monitoring system controls the two electrical monitoring substations to continue to acquire the next group of monitoring data.

Step six: quality control: after a group of complete monitoring data acquisition and corresponding signal processing are completed, the memory carries out quality evaluation and control on the group of monitoring data, the monitoring data are marked as qualified monitoring data and unqualified monitoring data, and processing results are stored in real time to prepare for subsequent monitoring data processing.

Step seven: data processing and imaging: the electric monitoring data processor is used for processing and inversion imaging of monitoring data with qualified quality, and subsequent data processing is not needed for monitoring data with unqualified quality. In the process of monitoring data acquisition, the electrical monitoring data processor continuously accesses the database of the memory, and when a group of monitoring data with qualified quality is detected, the group of monitoring data is preprocessed and inverted for imaging. Preprocessing the qualified monitoring data: firstly, correcting positive and negative attributes of observation voltage of positive and negative attributes of monitoring data; correcting the electrode polarization effect of the data abnormality caused by the electrode polarization effect in the monitoring data; and then, carrying out electrode consistency correction on the influence of electrode corrosion and shallow part nonuniformity in the monitoring data, finally carrying out inversion imaging on the monitoring data obtained by preprocessing, and storing the result obtained in the process and the final inversion imaging result in a database of a memory.

Step eight: carrying out mine water disaster hidden danger electrical method detection: before the stoping of the working face is not started, collecting multiple groups of complete monitoring data to suppress the influence of random noise on the data through repeated detection; superposing and averaging a plurality of groups of monitoring data to obtain a group of detection data, and storing the group of detection data into a database of a memory; setting an electrical method monitoring data processor into a manual mode, and utilizing the electrical method monitoring data processor to carry out preprocessing and inversion imaging on the group of detection data obtained by superposition averaging, wherein the obtained imaging result is the background resistivity of the coal bed which is not influenced by coal mining activities; defining a resistivity abnormal area according to the background resistivity, and marking the corresponding area as a key area for later-stage monitoring; if a strong low-resistance abnormal area exists in the background resistivity, drilling verification work needs to be carried out, and the hidden danger of water damage is eliminated.

Step nine: carrying out mine water disaster hidden danger electrical monitoring: after the working face begins to adopt, carrying out real-time monitoring data acquisition and processing interpretation work; when the electrical method monitoring data processor is subjected to data preprocessing and inversion parameter configuration, setting the background resistivity obtained in the step eight as a reference model for performing mixed weight constraint inversion, so as to perform further prior information constraint on the inversion process, and highlight the change condition of the current monitoring result (namely the resistivity result obtained after inversion imaging of the monitoring data) relative to the background resistivity; after the data preprocessing and the inversion parameter configuration are finished, setting the electrical method monitoring data processor into an automatic operation mode, and performing real-time processing imaging on the monitoring data; when a technician performs comparative analysis on the monitoring imaging result, the resistivity change condition marked as a key area needs to be concerned; when the resistivity is abnormally changed, early warning needs to be sent out in time for potential water damage risks.

By utilizing the electrical detection and monitoring integrated process method for the mine water damage hidden danger, provided by the invention, an observation system for detection and monitoring is uniformly deployed, water damage hidden danger detection is firstly developed, a monitored key area is determined by using detection results, and meanwhile, a background reference model is established by using the detection results to guide geological interpretation of the monitoring results. The same acquisition system can be shared for detection and monitoring, the construction amount of underground operation is reduced, and the interpretation precision of monitoring results is improved.

2. Electric monitoring system software part for mine water disaster hidden danger

The following describes the software part of the invention in detail from 6 aspects based on the mine water disaster hidden danger electrical method monitoring system of the invention.

1. Multifunctional data acquisition and processing method for mine electrical method

The underground coal mine belongs to a special and explosive gas filled dangerous operation environment, all instruments and equipment need to meet the requirements of industrial explosion-proof electricity and obtain related inspection permission, so that when the underground coal mine is monitored by an electrical method, the power of an electrical method field source is strictly limited, a field source response signal is extremely weak, and the underground coal mine has a very high requirement on the weak signal acquisition capacity of monitoring equipment. And when the electrical method data acquisition is carried out, the monitoring electrode is driven into a coal seam bottom plate or a coal seam top plate, the signal acquisition input end of the monitoring equipment is directly connected with the ground, no signal isolation measure is provided, so that the grounding of large electromechanical equipment such as coal mining machines, power transformation equipment and belt conveyors under coal mines causes great electromagnetic interference of signals to the monitoring electrode, and along with the development of a frequency conversion technology, the type and frequency distribution of the electromagnetic interference are gradually complicated and changeable, and the pollution to field source target frequency points is possibly caused. And the electrical method monitoring needs to carry out data acquisition in the full time flow during the exploitation period, and the direct electromagnetic interference is inevitably needed, which puts more rigorous requirements on a signal processing circuit at the front end of the data acquisition of the monitoring instrument, anti-interference measures and a data processing method. In summary, when data acquisition is monitored by an electrical method, the data processing method faces more severe challenges than manual electrical exploration. Firstly, broadband interference needs to be suppressed, and the signal-to-noise ratio of a received signal is improved; secondly, richer observation data need to be obtained in a limited observation space so as to apply appropriate prior information to the resistivity inversion process for constraint and improve the imaging resolution of the inversion result on the abnormal body space position and the spreading range.

Based on the above, the invention provides a multifunctional data acquisition and processing method for mine electrical method by using the electrical method monitoring system for mine water disaster hidden danger, which comprises the following steps:

step 1: the substation controller 8 of each electrical method monitoring substation obtains the IP address distributed by the electrical method monitoring system controller 5 to the substation controller 8 through the network communication module 15;

step 2: the electrical method monitoring system controller 5 selects a signal acquisition mode to be an electrical section mode or an electrical perspective mode; when the electrical section working mode is selected, setting the superposition times (the superposition times can be selected to be 1 time, 5 times and 10 times) and the magnification (the magnification is the combination of the first-stage magnification and the second-stage magnification); when the electric perspective working mode is selected, setting sampling frequency (1200 Hz, 2400Hz, 4800Hz, 7200Hz and 14400Hz, optionally), sampling time (1s to 12s) and magnification (the magnification is the combination of first-level magnification and second-level magnification);

and 3, step 3: the substation controller 8 receives a control command from the electrical method monitoring system controller 5, and configures a first-stage filtering amplification module 20, a second-stage amplification module 22 and an AD acquisition module 24 which meet the set parameters in the second step;

and 4, step 4: according to different signal acquisition modes, the embedded central control module 10 generates different control logic signals, and connects the receiving electrode gated by the switch matrix module 13 to the input end of the first-stage filtering amplification module 20;

and 5: when the data acquisition of the electric cross-section method is carried out, the substation controller 8 captures a field source emission signal, namely a direct-current square wave signal, generates a trigger signal synchronous with the rising edge and the falling edge of the direct-current square wave signal and sends the trigger signal to the AD sampling module 22, the AD sampling module 22 starts to carry out data acquisition after receiving the trigger signal, 20 values of a positive emission half period are acquired at the rising edge, and 20 values of a negative emission half period are acquired at the falling edge, so that the electric section data are acquired according to the direct-current square wave signal, and the acquired electric section data are processed in the step 6;

and 6: and carrying out superposition averaging on the acquired data to obtain a measured value, calibrating the acquired signal by using a square wave signal source, calculating to obtain an experimental value, obtaining an observation voltage coefficient according to the experimental value, and calculating to obtain a final observation voltage according to the measured value and the observation voltage coefficient. The method comprises the following substeps:

(1) The superposition average obtains the measured value: collecting 20 values of the positive transmitting half period at the rising edge, deleting the first 2 values and deleting the last 2 values so as to eliminate the influence of the rising edge and the falling edge slope on the data; then deleting the maximum value and the minimum value in the remaining 16 values to eliminate the influence of random interference on data; the remaining 14 values were then averaged and recorded as U _p (ii) a20 values of the negative half-transmission period are acquired at the falling edge, and are processed similarly and are marked as U _n (ii) a Thus, the voltage value of positive and negative half cycles in a low-frequency square wave period is obtained; take U = | (U) _p -U _n ) I/2 as a measured value S of one square wave period _Measuring (ii) a If the superposition times are more than 1, averaging the measured values of a plurality of square wave periods to obtain a measured value S _Measuring ；

(2) Calibrating the observation data coefficient by an electro-sectioning method: calibrating the electrical profile data collected in the step 5 by using a square wave signal source in a laboratory; square wave signalThe absolute value of the amplitude of the source is noted as S ₀ And the average value of the absolute values of the amplitude values of the acquired square wave signals is recorded as S _{Experiment of} The observation voltage coefficient calculation formula is as follows: δ = S ₀ /S _{Experiment of} (ii) a Calibrating for multiple times by using square wave signal sources with different amplitudes, calculating observation voltage coefficients under different amplitudes, and calculating an average value of the observation voltage coefficients obtained by calibrating for multiple times to serve as a final observation voltage coefficient delta;

(3) Calculating an observation voltage: the calculation formula is as follows: u = δ × S _Measuring 。

And 7: when the data acquisition is carried out by the electro-fluoroscopy method, the full-waveform real-time acquisition is carried out. The AD sampling module 22 performs electric perspective data acquisition according to the set sampling frequency and sampling time to obtain a full waveform file of the pseudo-random multi-frequency signal, and executes the step 8 to perform data processing;

and 8: and carrying out data processing on the full waveform file of the acquired pseudorandom multi-frequency signal so as to suppress electromagnetic noise under the coal mine and improve the signal-to-noise ratio of the received signal. The method specifically comprises the following substeps:

(1) Calibrating a single-frequency receiving signal and calculating an observation voltage value:

if the field source transmits a signal as a single frequency wave, the frequency is recorded asf ¹ The target resolving frequency point corresponding to the received signal is the samef ¹ (ii) a Giving an amplitude of Z by means of a source of a sine wave signal ₀ At a frequency off ¹ The sine wave of (2) is input to the signal input end of the first-stage filtering and amplifying module 20; the substation controller 8 sets initial acquisition parameters, namely sampling frequency k =1200Hz, sampling duration τ =1s, and amplification factor v =1, to acquire data; obtaining the frequency response Z of the transmitted signal and the received signal by correlation detection ₁ Then the target frequency pointf ¹ Calibration factor of

At a transmission frequency off ¹ When different sampling frequencies k, sampling duration tau and amplification factors v are selected for data acquisition, marking the target frequency point amplitude of the received signal as Zf ¹ Frequency point of interestf ¹ The voltage value calculation formula is as follows:

；

(2) Calibrating the pseudo-random multi-frequency signal and calculating an observed voltage value: the method comprises the following steps:

A. if the field source transmits signals as multi-frequency waves, the frequency is recorded as

The target resolving frequency point corresponding to the received signal is the same

(ii) a Frequency points are respectively obtained by adopting the calibration method of the single-frequency receiving signal

Calibration factor of

；

B. The observed voltage is calculated. Because the pseudo-random multi-frequency signal is formed by combining and superposing a plurality of frequencies according to the power of n of 2, the weight of each frequency point is set as

(ii) a After the pseudo-random multi-frequency signals are subjected to correlation detection, the obtained earth frequency responses of different frequency points are recorded as

The voltage value calculation formula of each main frequency point of the pseudo-random multi-frequency wave is as follows:

，

；

C. and voltage values of different frequency points are superposed and averaged. When the voltage values of a plurality of frequency points exist in the current measuring point (the current receiving electrode),

eliminating data with the largest deviation in the voltage values, and calculating the arithmetic mean value of the residual voltage values to obtain a final observed voltage value U, wherein the calculation formula is as follows:

，

for a single measuring pointiThe voltage value of each frequency is set to be,nthe number of the residual voltage values participating in the calculation.

In the past, a downhole direct current electrical detection instrument generally transmits and receives a single-frequency signal, and original data with good quality can be acquired by avoiding a strong interference source in time or space. However, in the monitoring process, the type of electromagnetic noise is complex, the intensity is extremely high, the electromagnetic noise changes along with space-time change, the electromagnetic noise cannot be avoided in space-time, the interference characteristics and the type of the electromagnetic noise are difficult to predict, and once the transmitting frequency is in a strong interference frequency band, effective signals are difficult to acquire. Because the frequency components of the multi-frequency signals are more and dispersed, under the condition that the interference frequency band is unknown, the data influenced by strong electromagnetic interference can be eliminated, and the purpose of improving the signal-to-noise ratio of effective data is achieved. In addition, the underground direct current method monitoring belongs to geometric depth measurement, and earth responses with different frequencies are basically consistent under the condition of not considering the induced polarization effect. Therefore, after the data affected by strong electromagnetic interference is eliminated, the earth response of a single frequency can be replaced by calculating the arithmetic mean of the earth responses of the frequencies. The calculation method can achieve the effect of collecting the single-frequency signals point by point for multiple times on the premise of not consuming instrument memory additionally and not reducing the working efficiency, and further improves the signal-to-noise ratio of effective data. Compared with the prior art, the method has the following beneficial effects:

the method is compatible with data acquisition of an electro-sectioning method and data acquisition of an electro-fluoroscopy method, data acquisition of different methods is carried out in a time-sharing mode, richer observation data are obtained in a limited observation space, proper prior information can be applied to the resistivity inversion process for constraint, and the imaging resolution of the inversion result on the space position and the spread range of an abnormal body is improved. In addition, a two-stage amplifying circuit is adopted for signal processing, an AD acquisition module is adopted for signal synchronous acquisition, and the device has excellent weak signal resolution capability. Meanwhile, the method for processing the pseudo-random multi-frequency signals by adopting a multi-frequency superposition method can effectively suppress broadband electromagnetic noise in the underground coal mine and improve the signal-to-noise ratio of received signals.

2. Quality control process for electrical monitoring data

The method mainly aims at a detection task, is poor in applicability and single in means when monitoring data, and does not form a relevant technology to meet the requirement of monitoring data control of the underground direct current method at the present stage.

Based on this, in the above-mentioned electric monitoring system for mine water damage hidden danger of the invention, the seventh step of the working process of the memory is: the method comprises the following steps that the memory carries out quality evaluation and control on a group of complete original monitoring data through a quality control process of electrical monitoring data, and screening and marking the monitoring data with qualified quality, and specifically comprises the following steps:

step 1: evaluation of emission current: selecting a single group of monitoring data, presetting a maximum threshold and a minimum threshold of emission current, evaluating the size and stability of the emission current of the group of evaluation units by taking a single emission electrode as a group of evaluation units, rejecting unqualified data after all evaluations are finished, and entering the next step for qualified data;

wherein: maximum threshold value of emission currentI _max For monitoring the maximum achievable emission current of the system, minimum thresholdI _min And estimating through a field test in the monitoring system layout stage, and setting according to experience when the field test result is not ideal. When the emission current exceeds the threshold value, the electric potential or the electric potential difference corresponding to the unqualified measuring point in the group of evaluation units is rejectedAnd (4) data. In particular, estimation by field testsI _min The formula of (1) is as follows:

I _min =A _min I _s /A _smin

wherein the content of the first and second substances,I _min is a minimum threshold of the emission current, andA _smin under the same apparatus conditions;A _min minimum signal distinguishable for the monitoring instrument;I _s is the emission current of the field test;A _smin the minimum potential or potential difference received by each measuring point in the field test.

Preferably, a maximum threshold value of the emission current is setI _max 80mA, minimum thresholdI _min At 30mA, received data with a transmit current within this range is considered acceptable.

Wherein: the stability of the emission current is evaluated by the relative mean square error of the set of emission currents, and the calculation formula is as follows:

wherein, the first and the second end of the pipe are connected with each other,m _I is the relative mean square error of the set of transmit currents,nin order to select the number of the measuring points corresponding to the transmitting electrode,I _j for the emission current data of a single station,

is composed ofnAnd (4) averaging emission current data of each measuring point.

In this embodiment, the relative mean square error threshold of the emission current is set to be 5%, the emission current is considered to be unstable when the relative mean square error threshold is higher than the threshold, and all data corresponding to the group of evaluation units are rejected.

And 2, step: evaluation of raw data noise level: aiming at the current monitoring data processed in the step 1 (namely qualified data obtained in the step 1), carrying out Fourier transform on the full waveform data of each measuring point to obtain frequency spectrums with different frequencies, and further calculating the signal-to-noise ratio of the data of each measuring pointSNREvaluating the difference one by oneAnd (4) measuring the noise level of the original monitoring data of the points, eliminating potential or potential difference data corresponding to unqualified measuring points in the group of evaluation units, and entering the next step for qualified data.

Wherein: step 2, calculating the signal-to-noise ratio of each measuring point, wherein the specific calculation formula is as follows:

wherein, in the step (A),V _signal a frequency spectrum of a transmission frequency obtained by performing fourier transform on the full waveform data;V _noise the full waveform data is Fourier transformed to obtain the frequency spectrum of the noise in the frequency band near the transmitting frequency. The frequency band near the transmission frequency is a frequency band with a certain bandwidth and taking the transmission frequency as a center.

Specifically, the bandwidth of the frequency band near the transmission frequency is determined according to the sampling frequency and the sampling duration, and should at least include 10 frequency points. In the embodiment, the bandwidth of a frequency band near the transmitting frequency is set to be 5Hz; and setting the signal-to-noise ratio threshold of the data to be 10dB, and considering the data quality to be qualified when the threshold is higher than the threshold.

And step 3: data stability was evaluated spatially: regarding the current monitoring data processed in step 2 (i.e. the qualified data obtained in step 2), a single transmitting electrode is used as a group of evaluation units, and if the ratio of the measuring points of a single group of evaluation units is small after step 2 (less than 80% in this embodiment), step 4 is directly entered; otherwise, the potential of each measuring point is measuredV _i Or the potential difference deltaV _i Forming an actually measured curve (namely a potential or potential difference change curve), taking a single transmitting electrode as a group of evaluation units, evaluating the stability of data from space, and then entering the current monitoring data processed in the step 2 into a step 4; at this point, the single set of monitoring data processing is complete.

Wherein: data stabilization criteria include: in a group of evaluation units, the potential or potential difference curve of each measuring point is smooth and has good continuity and clear curve form; in two adjacent groups of evaluation units, the type regularity of the potential or potential difference curve of each measuring point is better.

Step 3, data are not removed, a curve is formed for the data of a single group of evaluation units with more qualified measuring points (80% and above) in the step 2, the curve is subjected to space stability and an evaluation conclusion is formed, the conclusion is used as the basis of a subsequent working link after the method is finished, and the subsequent working link is processed according to the space stability evaluation conclusion (namely curve characteristics) of the potential or potential difference curves of different evaluation units obtained in the step 3; the data of a single transmitting electrode with less qualified measuring points (less than 80%) in the step 2 directly enters the step 5 of the method. And 3, the main function of the step 3 is to observe whether the problems of static effect, electrode polarization, infinite distance deficiency and the like exist in the construction process, and the single group of evaluation units cannot be used when fewer qualified measuring points exist.

And 4, step 4: repeating the step 1-3 to obtain a plurality of groups of monitoring data;

and 5: data stability was evaluated over time: selecting monitoring data with adjacent acquisition time within 48 hours (preferably 8 groups of monitoring data with adjacent acquisition time) from the monitoring data obtained in the step 4, drawing a potential or potential difference change curve of the monitoring data of a single measuring point along with the time by taking the single measuring point as an evaluation unit, calculating the relative mean square error of each measuring point, and evaluating the data stability in time;

wherein: this example selects 8 sets of monitoring data over a 48 hour period and has continuity in time. The time continuity means that a plurality of groups of monitoring data are sequentially selected according to a time sequence, meanwhile, the plurality of groups of monitoring data are under the same underground production environment condition, namely, the data of a production class and a maintenance class are distinguished, and part of time periods are not required to be underground production and part of time periods are required to be underground shutdown. This step is performed on the premise that the number of monitoring data in 24 hours reaches 3 sets or more, and the number of monitoring data in 48 hours reaches 5 sets or more.

Wherein: the potential or potential difference relative mean square error calculation formula of a single measuring point is specifically as follows:

wherein the content of the first and second substances,m _s is the relative mean square error of the individual measuring point potentials or potential differences,nfor the number of sets of monitoring data selected, this example is 8,S _i is the first of the measuring pointiThe group potential or potential difference monitors the data,

for the measuring pointnThe group potential or potential difference monitors the data mean.

Wherein: setting the potential or potential difference of a single measuring point to be 5% relative to the mean square error threshold value, and considering that data in the threshold value range is stable; relative mean square error of single measuring pointm _s If the deviation is more than 5% and the data with larger deviation is in the middle section of the curve, a plurality of groups of related steps such as monitoring data processing and the like need to be added in the subsequent data processing of the method. The technical solution in the embodiment of the method will be clearly and completely described below with reference to the drawings in the embodiment.

Fig. 9 is the emission current for all raw data in a single set of monitored data. In the embodiment, the evaluation criterion considers that the original data in which the emission current is lower than 30mA does not contain the emission frequency signal, the subsequent processing stage eliminates part of data smaller than 30mA in the original data for analyzing noise, and the rest part of data enters the data quality analysis of the following step.

In this embodiment, the evaluation criterion is considered as the relative mean square error of a single set of transmit currentsm _I When the emission current is less than or equal to 5%, the emission current is stable, and the data quality analysis of the following steps is directly carried out on the corresponding original data; relative mean square error of a single set of transmit currentsm _I If the emission current is unstable when the emission current is more than 5%, corresponding data are removed, and a subsequent data quality control flow and other related data processing flows are not started.

Fig. 10 is the signal-to-noise ratio of all raw data in a single set of monitored data after processing in step 1. The signal-to-noise ratios of different measuring points in the group of data are generally between-40 and 60dB, wherein the signal-to-noise ratios of the measuring points at point 900 and before the point 900 are generally between 20 and 60dB, which shows that the noise is about 10 percent of the amplitude of the effective signal, and the signal-to-noise ratios of the measuring points at point 901 and after the point 901 are generally between-20 and 10dB, which shows that the noise is basically equivalent to the amplitude of the effective signal.

The evaluation criterion considers that the original data with the signal-to-noise ratio lower than 10dB is seriously influenced by interference, and the part of data does not enter a subsequent data quality control flow.

FIG. 11 is the potential difference of all the raw data in a single set of monitored data after processing in step 2. The potential value of the measuring point curve of the small point is large, the curve form is clear, and the regularity of the curve type is good; the potential value of a measuring point curve of a large point is small, the curve form is difficult to identify, the curve type regularity is poor, and the large point is probably caused by that a transmitting electrode gradually approaches infinity, a received signal is weakened due to the influence of the infinity, and the signal to noise ratio is reduced.

FIG. 12 shows the potential difference of the partial measuring points after the processing of step 3 and step 4, wherein the average value of the original data of measuring point No. 89 is 19.48μV, relative mean square errorm _s 2.04 percent; the mean value of the original data of the measuring point No. 90 is 16.98μV, relative mean square errorm _s 6.18 percent; the mean value of the raw data of the measuring point No. 91 is 27.55μV, relative mean square errorm _s It was 16.18%.

The evaluation criterion is that: relative mean square error of measured pointm _s If the deviation is more than 5%, and the data with larger deviation is in the middle section of the curve, the measuring point is considered to be subjected to larger short-time random electromagnetic interference, and a plurality of groups of related steps such as monitoring data processing and the like need to be added in subsequent data processing.

The principle of the present embodiment will be described below.

In order to ensure safe production of the downhole working face, downhole electrical methods are often provided with overcurrent protection. The same emission electrode has stable emission current due to unchanged grounding condition, and the emission electrode has step phenomenon when changed, so that the emission current needs to be evaluated by taking a single emission electrode as a group. If the emission current is too large, the problem of the instrument is shown; if the emission current is too small, the transmission end wire or the electrode is damaged in the mining process; if the transmitting current is unstable, the electrode of the transmitting terminal is likely to be loosened, the grounding condition is likely to be changed greatly, or the instrument of the transmitting terminal is likely to be unstable.

When the noise level of the original data is evaluated, the original data frequency spectrum mainly comprises a single or a plurality of emission frequency signals, strong interference power frequency signals and harmonic waves thereof, and the rest background noise is close to Gaussian white noise. The intensity of the background noise is related to the number and the intensity of electromagnetic interference sources of the roadway where the transmitting end and the receiving end are located. The sub-stations 901 to 1800 take the main in-tank electrode transmission and the auxiliary in-tank electrode reception, so that the background noise is obviously stronger, the signal to noise ratio of the signal is lower, and the data quality evaluation is poorer.

When the data stability is evaluated in space, under the condition of a single transmitting electrode, the potentials or potential differences of different measuring points are gradually changed and smooth, and the sawtooth phenomenon shows that the original data are influenced by the outside, so that the receiving end electrode is possible to be loosened and the grounding condition is poor; if the same problem still occurs when the receiving electrode is replaced, a static effect may occur when the receiving electrode is located on the non-uniform body, or a polarization phenomenon may occur in the receiving electrode, and a corresponding correction step needs to be added in the subsequent data processing. Under the condition of adjacent transmitting electrodes, the receiving curve forms of different measuring points are similar or gradually changed and accord with the theory, the potential of the measuring point under the condition of a large-size transmitting electrode in the graph is integrally small and does not accord with the theory, the potential is possibly influenced by infinite distance deficiency, and a corresponding correction step needs to be added in subsequent data processing.

When the stability of the data is evaluated in time, the mining damage process of the top and bottom plates and the development process of the water guide channel are gradually changed in the mining process, so that the mining damage process can be approximately regarded as static in a short time period. The curve form fluctuation represents that the measuring point is influenced by continuous interference, the interference intensity is high, and the stability is poor; a single or a small number of distortion points appear in the middle of the curve to represent that the measuring point is influenced by short-time interference; if the tail branch of the curve is continuously and obviously changed (not less than 3 points), whether the tail branch of the curve is abnormal caused by the damage of a top bottom plate and the development of a water guide channel in the excavation process needs to be considered.

Compared with the prior art, the method has the beneficial effects that:

the data management and control process is based on the characteristics of automation, intellectualization and full waveform uninterrupted data acquisition of underground direct current method monitoring, adopts qualitative and quantitative evaluation methods aiming at three aspects of emission current, original data noise and data stability level, and evaluates and manages and controls the underground direct current method monitoring original data. Firstly, the problem of the emission current does not appear in the conventional electrical prospecting, but can be found and avoided in the field construction stage generally, but the underground direct current electrical monitoring runs through the whole working face construction process, and the electrodes and the electric wires for emission and reception are easily damaged due to the influence of the excavation activity, so that the emission current needs to be subjected to normalized control. Secondly, the original data noise level table mat is quantitatively evaluated aiming at the influence of continuous stable noise, and the signal-to-noise ratio of the emission frequency can be directly obtained. Finally, in view of the difficulty in manual arrangement of detection points in the automatic monitoring process, the flow utilizes the characteristics of gradual change in the space and time of monitoring data to manage and control the data quality aiming at random electromagnetic noise in a short time. In conclusion, the method is strong in pertinence, suitable for underground electrical method monitoring data, rich in evaluation means, capable of relatively comprehensively reflecting noise interference level and providing a reliable basis for subsequent electrical method monitoring data processing.

This is illustrated by comparative tests.

The following comparative tests were designed, selecting certain mine monitoring data for quality control according to the procedures described herein, comparing with monitoring data where a station is not quality controlled, and fig. 13 is a graph of monitoring data before (upper) and after (lower) quality control. It can be seen that, after quality control is performed on the monitoring data through the process described herein, the signal-to-noise ratio of the reserved monitoring data is generally over 30dB, which is available effective data, and meanwhile, the control process provides a selection basis for a subsequent processing method for the original data under different conditions, so that the purpose of effectively controlling the quality of the monitoring data is achieved.

3. Method for correcting positive and negative attributes of observed voltage with respect to electrical monitoring data

The electric monitoring system for the mine water damage hidden danger cannot distinguish the positive attribute and the negative attribute of the voltage when data acquisition is carried out, and for a monopole-dipole working mode and a dipole-dipole working mode, an actual voltage value exceeding a certain observation range can have a negative value, so that the observation range can only be limited in a region with a positive voltage when the data acquisition is carried out by utilizing the two working modes. In order to break through the limitation of the observation range, a method for distinguishing the positive and negative properties of the observation voltage is urgently needed.

Based on this, in the above-mentioned electric method monitoring system for mine water damage hidden danger of the present invention, in the third step of the work flow of the electric method monitoring data processor, the positive and negative attributes of the monitoring data taken out from the memory are corrected by using the observed voltage positive and negative attribute correction module, and the method includes the following steps:

step 1, marking a first group of monitoring data as initial monitoring data; marking the monitoring data obtained by subsequent repeated detection as subsequent monitoring data; each set of monitoring data is regarded as a set of independent monitoring data; when the initial monitoring data and the subsequent monitoring data exist, the continuous monitoring data are regarded as existing;

when the collected monitoring data only comprise initial monitoring data, executing the step 2 to correct the positive and negative attributes of the observed voltage value;

when the collected monitoring data is continuous monitoring data, performing step 2 on the initial monitoring data to correct the positive and negative attributes of the observed voltage value, and performing step 2 or step 3 on the subsequent monitoring data to correct the positive and negative attributes of the observed voltage value;

step 2, on the basis of the theoretical voltage curve, correcting the positive and negative attributes of the observed voltage value of the independent monitoring data by using the position relation of the measuring points where the transmitting electrode and the receiving electrode are located, and specifically comprising the following substeps:

step 21, for the monopole-dipole working mode, the transmitting electrode is a monopole, and the receiving electrode is a dipole; the emitter electrode is denoted by A and the coordinates are given

（

），NsThe total number of the emitter electrodes; the receiving electrodes are represented by M and N, and the coordinates are respectively expressed as

（

) And

（

），Nrthe total number of receiving electrodes; the observed voltage value is recorded as

The corrected voltage value is recorded as

；

Judging the interval in which the voltage has a negative value according to a theoretical voltage curve of a monopole-dipole working mode: under the condition that the polar running direction is from left to right, when the receiving point is positioned at the left side of the transmitting point, the voltage is a negative value, when the receiving point is positioned at the right side of the transmitting point, the voltage is a positive value, and the positive and negative attributes of the voltage value are related to the relative positions of the transmitting and receiving measuring points; monopole-dipole working mode transmitting-receiving measuring point position relationC _AMN The calculation formula of (a) is as follows:

wherein, the first and the second end of the pipe are connected with each other,

being the distance between the transmitting electrode a and the receiving electrode M,

；

being the distance between the transmitting electrode a and the receiving electrode N,

；

the correction formula of the positive and negative properties of the observation voltage of the monopole-dipole working mode is as follows:

，

（

）

step 22, for the dipole-dipole working mode, the transmitting electrode is a dipole, and the receiving electrode is a dipole; the emitter electrodes are represented by A and B, and the coordinates are recorded

（

) And

（

），Nsis the total number of the emitting electrodes; the receiving electrodes are represented by M and N, and the coordinates are respectively expressed as

（

) And

（

The corrected voltage value is recorded as

；

Judging the interval in which the voltage has a negative value according to a theoretical voltage curve of a dipole-dipole working mode: under the condition that the electrode running direction goes from left to right, all voltage values are negative values when single-measuring-line high-density electrical method data acquisition is carried out; when the dual-measurement-line electric perspective method data acquisition is carried out, the voltage value in a sector area just opposite to the emission point is positive, the voltage value outside the sector area is negative, and the range of the sector area is related to the distance and the included angle of the measurement lines; the positive and negative attributes of the voltage values are related to the relative positions of the transmitting and receiving measuring points; dipole-dipole working mode transmitting-receiving measuring point position relationC _ABMN The calculation formula of (c) is as follows:

the distance between the transmitting electrode a and the receiving electrode M,

；

the distance between the transmitting electrode a and the receiving electrode N,

；

the distance between the transmitting electrode B and the receiving electrode N,

；

；

the correction formula of the positive and negative properties of the dipole-dipole working mode observation voltage value is as follows:

（

，

）

when the direction of the electrode running is different from the above direction, the positive and negative attribute intervals of the voltage value change, but the calculation formulas of step 41 and step 32 are also applicable.

And 3, correcting the positive and negative attributes of the observed voltage value of the subsequent monitoring data by using a background elimination method, wherein the method specifically comprises the following operations:

the monitoring data comprises observation voltages of different measuring points, belongs to a one-dimensional vector, and records the initial monitoring data as

And recording the subsequent monitoring data

，NtThe total amount of the monitoring data; recording the corrected monitoring data as

(ii) a Record the simulation monitoring data of any uniform medium

The simulation monitoring data is obtained by calculation through a theoretical formula of the electric field distribution of the point power supply, and the positive and negative properties of the voltage value are completely consistent with a theoretical voltage curve; the positive and negative voltage attribute correction formula of the subsequent monitoring data is as follows:

，

by passing

Can eliminate the influence of background environment and has

>0, such that

And

the positive and negative attributes of the elements in (1) are completely consistent.

And 3, the method for correcting the positive and negative attributes of the observation voltage of the continuous monitoring data by using the background elimination method is suitable for different observation methods and different working modes.

Compared with the prior art, the method has the beneficial effects that:

on the basis of a theoretical voltage curve, the position relation of the transmitting and receiving measuring points is utilized to correct independent monitoring data, the background elimination method is utilized to correct continuous monitoring data, the positive and negative properties of a corrected voltage value and an actual voltage value can be guaranteed to be consistent on the premise of not losing effective observation data, and the detection resolution and the interpretation precision of a monitoring result are greatly improved. The continuous monitoring data are corrected by using a background elimination method, the influence of system errors and a background environment can be eliminated, and weak resistivity abnormity under the background of uneven highness can be highlighted by performing inversion imaging on the corrected monitoring data.

Example (b):

to verify the feasibility and effectiveness of this method, a physical simulation test of a water tank was developed in this example. When carrying out basin physical simulation test, 3 metallic bodies are laid to the surface of water below, and the similar ratio of model size is 1:250, used for simulating a low resistance abnormal body. The positions of the abnormal bodies on the left side and the right side are fixed in the whole test process, and the position of the abnormal body in the middle gradually rises in the whole test process so as to simulate the process that the water-guiding geological structure gradually grows upwards. And a dipole-dipole working mode is adopted for data acquisition. When initial monitoring data are collected, the middle abnormal body is positioned at the depth of 28 cm; when the subsequent monitoring data is collected, the middle abnormal body is positioned at the depth of 16 cm.

The inversion imaging results without correction for subsequent monitoring data of the water tank physical simulation are shown in fig. 14. The imaging results in the figure show that strong false anomalies appear at the left and right ends of the observation region, and the middle anomaly and the small-scale anomalies at the left and right sides are not basically reflected in the imaging results.

According to the step 2 of the method, the positive and negative attributes of the observed voltage are corrected by using the position relation of the transmitting and receiving measuring points on the subsequent monitoring data of the physical simulation of the water tank shown in the figure 14.

For dipole-dipole mode of operation, the transmission is a dipole and the reception is a dipole; the emitter electrodes are denoted by A and B, coordinates are noted

(while line 1 is transmitting

(ii) a When the measuring line 2 is launched

) And

(while line 1 is transmitting

(ii) a When the measuring line 2 is launched

) (ii) a The receiving electrodes are denoted by M and N, and the coordinates are respectively expressed as

(line 1 receiving

(ii) a When the measuring line 2 receives

) And

(line 1 is receiving

(ii) a When the measuring line 2 receives

) (ii) a The observed voltage value is recorded as

The corrected voltage value is recorded as

(ii) a Judging the interval in which the voltage has a negative value according to a theoretical voltage curve of a dipole-dipole working mode: under the condition that the polar direction runs from left to right, when the dual-measurement line electric perspective method data acquisition is carried out, the voltage value in the sector area opposite to the emission pointIf the voltage value is positive, the voltage value outside the sector area has a negative value, and the range of the sector area is related to the distance and the included angle of the measuring lines; the positive and negative attributes of the voltage values are related to the relative positions of the transmitting and receiving measuring points; the calculation formula of the dipole-dipole working mode transmitting and receiving measuring point position relation is as follows:

，

，

，

；

wherein: when the measuring line 1 transmits and the measuring line 2 receives:

，

；

when the measuring line 2 transmits and the measuring line 1 receives:

，

。

according to the step 2 of the method, the inversion imaging result of the water tank physical simulation subsequent monitoring data after the positive and negative attributes of the observation voltage are corrected by using the position relationship of the transmitting and receiving measuring points is shown in fig. 15. The imaging results in the figure show that due to the influence of the background environment such as the water tank boundary effect, false abnormalities occur near the boundary of the observation area, the middle abnormal body is weakly reflected in the imaging results, and the abnormal bodies on the left and right sides are not reflected in the imaging results.

According to the step 3 of the method, the positive and negative attributes of the observation voltage are corrected by utilizing a background elimination method to physically simulate the subsequent monitoring data of the water tank.

The monitoring data comprises observation voltages of different measuring points, belongs to a one-dimensional vector, and the initial monitoring data is recorded as

And the subsequent monitoring data is recorded as

，NtThe total amount of the monitoring data; recording the corrected monitoring data as D _k (ii) a Record the simulation monitoring data of any uniform medium as D ^c The simulation monitoring data is obtained by calculation through a theoretical formula of the point power supply electric field distribution, and the positive and negative properties of the voltage value are completely consistent with a theoretical voltage curve; the positive and negative voltage attribute correction formula of the continuous monitoring data is as follows:

，

；

by passing

Can eliminate background environmentHas the influence of

>0, so that D _k And D ^c The positive and negative attributes of the elements in (1) are completely consistent.

The method for correcting the positive and negative attributes of the observation voltage of the continuous monitoring data by using the background elimination method is suitable for different observation methods and different working modes.

In this embodiment, the analog monitoring data of the homogeneous medium is denoted as D ^c Recording the initial monitoring data of physical simulation of the water tank

Recording the subsequent monitoring data of the physical simulation of the water tank

Physically simulating subsequent monitoring data of the water tank by using a background elimination method according to step 5 of the method

The calculation formula for correcting the positive and negative properties of the observed voltage is as follows:

D ₂ utilizes a background elimination method to physically simulate subsequent monitoring data of the water tank

And carrying out the result of positive and negative attribute correction of the observation voltage.

According to step 3 of the method, the inversion imaging result after the observation voltage positive and negative attributes are corrected by using a background elimination method on the physical simulation subsequent monitoring data of the water tank is shown in fig. 16. The imaging result in the figure shows that the influence of background environment such as water tank boundary effect in the imaging result is eliminated, the middle abnormal body is reflected strongly in the imaging result, and the abnormal bodies on the left side and the right side are reflected strongly in the imaging result.

In conclusion, on the basis of the theoretical voltage curve, the independent monitoring data are corrected by using the position relation of the transmitting and receiving measuring points, and the continuous monitoring data are corrected by using the background elimination method, so that the positive and negative properties of the corrected voltage value and the actual voltage value can be ensured to be consistent on the premise of not losing effective observation data, and the detection resolution and the interpretation precision of the monitoring result are greatly improved; the background elimination method is used for correcting the subsequent monitoring data, the influence of system errors and background environment can be eliminated, and inversion imaging of the corrected monitoring data can highlight weak resistivity abnormity under the background of uneven highness.

4. Correction for electrode polarization effects

In the field of electrical method monitoring, because the monitoring electrode is buried underground for a long time and is directly contacted with surrounding rocks, the monitoring electrode is extremely easy to corrode and polarize under the high-temperature and high-humidity environment of a coal mine underground, and generates large interference on monitoring data. If the corrosion resistance and polarization resistance of the electrode are improved by electrode process improvement, the electrode processing cost is increased. However, when monitoring the water damage hidden danger of the mine is carried out, the monitoring electrode cannot be reused generally, so that the problem that the reduction of the electrode cost is important to consider in the construction process of monitoring the water damage hidden danger of the mine is solved. In the electric monitoring system for the water damage hidden danger of the mine, in order to reduce the construction cost, an anchor rod or stainless steel is generally used as a monitoring electrode when monitoring the water damage hidden danger in a roadway, and the electrode is easy to corrode and polarize in the underground coal mine monitoring environment.

Based on this, in the above-mentioned electric method monitoring system for mine water damage hidden danger of the present invention, in the third step of the work flow of the electric method monitoring data processor, the electrode polarization effect correction module is used to correct the data abnormality caused by the electrode polarization effect in the monitoring data, and the specific steps are as follows:

step 1, measuring a correction coefficient of an electrode through an experiment, and specifically comprising the following steps:

step 11, adopting a single-pole-single-pole working mode to measure experimental data; marking the tested electrode as a No. 1 electrode, wherein the No. 1 electrode can be made of conductive materials such as stainless steel, copper, graphite and the like according to requirements; preparing 3 auxiliary electrodes, namely a No. 2 electrode, a No. 3 electrode and a No. 4 electrode in sequence, wherein the materials of the auxiliary electrodes are consistent with that of the No. 1 electrode;

step 12, installing the No. 1 electrode at the position of the measuring electrode and the No. 3 electrode at the position of the transmitting electrode according to the working modes of unipolar transmitting and unipolar receiving, wherein the distance between the No. 1 electrode and the No. 3 electrode is about 100 m; arranging the No. 2 electrode and the No. 4 electrode as infinite electrodes at a place which is kilometers away, and ensuring a sufficient distance between the No. 2 electrode and the No. 4 electrode;

step 13, forming a measuring loop by the electrode No. 1 and the electrode No. 2, and forming a power supply loop by the electrode No. 3 and the electrode No. 4; supplying power to a power supply loop formed by the No. 3 electrode and the No. 4 electrode, wherein the No. 3 electrode is connected with the positive electrode of a power supply during power supply, and the No. 4 electrode is connected with the negative electrode of the power supply; the power supply current is kept stable, and the power supply current and the power supply time are consistent with those of actual exploration equipment; the potential difference is measured by a measuring loop formed by the No. 1 electrode and the No. 2 electrode, and the measured value is recorded as

The measured value at this time is the measured value before the electrode No. 1 is not polarized;

step 14, performing power supply polarization on the No. 1 battery: replacing the No. 3 electrode with the No. 1 electrode, and installing the No. 1 electrode and the No. 4 electrode at the position of the transmitting electrode to form a power supply loop; supplying power to a power supply loop formed by the No. 1 electrode and the No. 4 electrode, wherein the No. 1 electrode is connected with the positive electrode of a power supply during power supply, and the No. 4 electrode is connected with the negative electrode of the power supply; the power supply current is kept stable, and the power supply current and the power supply duration are consistent with those of actual exploration equipment; at the moment, measurement is not needed, and the polarization of the No. 1 electrode is realized only by supplying power to the No. 1 electrode;

step 15, installing the No. 1 electrode back to the original measuring electrode position, and installing the No. 3 electrode back to the original transmitting electrode position; the No. 1 electrode and the No. 2 electrode form a measuring loop, and the No. 3 electrode and the No. 4 electrode form a power supply loop; supplying power to a power supply loop formed by the No. 3 electrode and the No. 4 electrode, wherein the No. 3 electrode is connected with the positive electrode of a power supply and the No. 4 electrode is connected with the negative electrode of the power supply during power supply; for supplying toThe electric current keeps stable, and the power supply current and the power supply time are consistent with those of actual exploration equipment; the potential difference is measured by a measuring loop formed by the No. 1 electrode and the No. 2 electrode, and the measured value is recorded as

The measured value at this time is the measured value after the electrode No. 1 is polarized;

step 16, defining a correction coefficient alpha; contrast U ₁ And U ₀ Size of (1), if U ₁ Greater than U ₀ α =1; if U is ₁ Is less than U ₀ ，α=-1。

Step 2, measuring a polarization potential difference attenuation curve of the electrode through an experiment, and specifically comprising the following steps:

taking out the No. 1 electrode, standing for a sufficient time until the polarization potential difference between the two ends of the electrode is reduced to 0; re-electrifying the No. 1 electrode (adopting the electrifying method in the step 14), stopping supplying power, and recording the power-off time (the electrodes are alternately electrified in actual exploration, the power supply time of a single electrode is fixed, the power supply loop of the current electrode is cut off after a certain time, the other electrode is connected into the power supply loop, and the power-off time refers to the time of cutting off the power supply loop of the current electrode) as t ₀ (ii) a Continuously measuring the polarization potential difference between two ends of No. 1 electrode by using a potential difference measuring device, and recording the measuring timet _i And measured value

Let us ordert = t _i - t ₀ In time oftIs the abscissa, the polarization potential difference

The decay curve of the polarization potential difference over time is plotted for the ordinate.

Step 3, selecting a proper fitting formula according to the change characteristics of the polarization potential difference attenuation curve obtained in the step 2, and obtaining a functional relation U between the polarization potential difference and time through curve fitting _{Polarization of} = f (t) And the polarization potential difference of the power supply electrode which is made of the same material as the No. 1 electrode at any moment after the power failure can be calculated through the functional expression.

Step 4, utilizing the functional relation U obtained in the step 3 _{Polarization of} = f (t) The method is used for correcting the polarization effect of the power supply electrode which is made of the same material as the No. 1 electrode, and comprises the following specific steps:

during the acquisition of electrical monitoring data, the electrodes used for power supply are marked by a control program and the time interval from the time of power supply to the time of signal measurement is recordedt(ii) a In the process of completing one-time complete data acquisition, each electrode only participates in one-time power supply, the power supply duration is fixed, but each electrode may participate in multiple signal measurement; each time an electrode participates in a signal measurement, if it has been marked as a powered electrode, it needs to update its duration from being used for power to being used for the signal measurement intervalt。

When signal measurement is carried out, whether the electrode participating in the measurement is marked as a power supply electrode is judged, and if not, no polarization effect correction is needed; if yes, correcting according to the following operations:

(1) When performing unipolar measurement, the current electrode is recorded as M, and U is obtained according to step 3 _{Polarization of} = f (t) Calculating the polarization potential difference of the electrode M

The formula for correcting polarization effect is as follows:

in the formula (I), the compound is shown in the specification,U _measuring Representing the measurement data;U _{correction of} Data indicating that the measurement data is corrected; α represents a correction coefficient of the electrode; obtained in step 1.

(2) When performing dipole measurement, let the electrode near the positive side of the power supply be M, the electrode near the negative side of the power supply be N, according to U _{Polarization of} = f (t) Respectively calculating the polarization potential difference of the electrode M and the electrode N

And

(ii) a If only one of the electrodes is used as an over-feeding electrode, the polarization potential difference of the other electrode is 0; the polarization effect correction formula is as follows:

。

the technical scheme realizes the polarization effect correction by utilizing the polarization potential difference attenuation curve of the power supply electrode, can well eliminate the influence of the electrode polarization effect, and belongs to a universal correction method.

When the time of the adjacent electrode participating in power supply is closer, the polarization potential difference can be offset through the recombination of the measured data of the adjacent electrode, and the polarization effect correction of the power supply electrode is realized. Because the electrode materials used in the data acquisition process are the same, the influence of the polarization effect on different electrodes is theoretically consistent. The difference of the polarization potential differences of different electrodes is mainly caused by different attenuation time, under the condition that the time of the adjacent electrodes participating in power supply is relatively close, the difference of the attenuation time is relatively small, the difference of the polarization potential differences is relatively small, and at the moment, the polarization potential differences can be counteracted through the recombination of the measured data of the adjacent electrodes, and the specific technical scheme is as follows:

(1) Under the condition that all the electrodes are sequentially involved in power supply, the unipolar-unipolar working mode measures the potential difference of a certain electrode relative to an infinite electrode, the infinite electrode at the measuring end generally does not participate in power supply, so that the influence of the polarization effect of the power supply electrode on unipolar-unipolar measurement data is large, and the technical scheme for correcting the polarization effect of the power supply electrode in the unipolar-unipolar working mode is as follows:

A. when the monopole-monopole working mode is adopted for measurement, the influence of electrode polarization effect can be reduced by extracting monopole-dipole observation data,recording unipolar-unipolar measurement data

，iIn order to number the measuring electrodes,i=1,2,3, \8230;, N; n is the total number of measuring electrodes, and the measured data includes the true potential difference and the polarization potential difference, i.e. the

，αIs a correction factor; and extracting observation data of the monopole-dipole working mode, wherein the extraction formula is as follows:

，

i=1,2,3,……,N-1；

the above formula applies to

And correcting the polarization effect of the power supply electrode of the time monopole-monopole observation data.

B. When the monopole-monopole working mode is adopted for measurement, the influence of electrode polarization effect can be reduced by extracting dipole-dipole observation data, and the monopole measurement data corresponding to two different power supply electrodes are respectively recorded as

And

，

；

and extracting observation data of the dipole-dipole working mode, wherein the extraction formula is as follows:

i=1,2,3,……,N-1；

the above formula applies to

Under the condition that all the electrodes are sequentially involved in power supply, when the time for the adjacent electrodes to participate in power supply is relatively close, the potential difference of the adjacent electrodes is measured in the monopole-dipole working mode and the dipole-dipole working mode, the polarization potential differences of the adjacent electrodes are basically counteracted mutually in the acquisition process, the influence of the polarization effect of the power supply electrode on monopole-dipole and dipole-dipole measurement data is relatively small, and the influence of the polarization effect of the electrodes can be ignored when the exploration equipment is adopted to directly measure the dipoles.

(2) When power is supplied across the electrodes and all the electrodes participate in measurement, for different working modes, sawtooth-shaped abnormity can occur in a measurement curve due to the influence of the polarization effect of the power supply electrode, and at the moment, the influence of the polarization effect of the electrodes can be eliminated through the superposition average of adjacent observation data. Because the monopole-dipole and dipole-dipole observation data can be obtained by the combined superposition of the observation data of the adjacent electrodes on the basis of the monopole-monopole observation data, the step of correcting the polarization effect of the power supply electrode when power is supplied across the electrodes is described by taking the case of only using the odd-numbered electrodes as an example on the basis of the monopole-monopole observation data, and the specific steps are as follows:

record the measurement data of the odd-numbered electrodes as

，（i ₁ Is the number of the odd numbers,i ₁ =1,3,5, \8230;), and measured data of even-numbered electrodes

，（i ₂ Is an even-numbered one and is,i ₂ =i ₁ + 1); the odd-numbered electrodes participate in the power supply,

(ii) a The even-numbered electrodes do not participate in the power supply,

；

the extraction formula of the monopole-dipole observation data is as follows:

i ₁ =1，3，5，……；i ₂ =i ₁ +1；

when the temperature is higher than the set temperature

，i ₁ =1,3,5, \8230, and when the power supply electrode polarization effect correction formula is as follows:

。

the above power supply electrode polarization effect correction formula for monopole-monopole observation data when only odd-numbered electrodes are used for power supply can be generalized to electrode polarization effect correction in other forms of cross-electrode power supply, and can be further generalized to power supply electrode polarization effect correction for monopole-dipole and dipole-dipole observation data in cross-electrode power supply. The method corrects the polarization effect of the power supply electrode by a data processing method, can effectively eliminate the influence of the polarization effect of the power supply electrode, improves the quality of detection/monitoring data, and lays a data foundation for high-precision interpretation of electrical prospecting results; the method does not need to carry out special process improvement on the electrode, thereby reducing the manufacturing cost of the electrode; the method does not need to plan the arrangement sequence of the electrodes again through a complex algorithm, thereby improving the utilization efficiency of the electrodes; the method fully considers the power supply electrode polarization effect correction under different use conditions, different working modes and different observation modes, and has universality.

Compared with the prior art, the method has the following beneficial effects:

(1) The method determines the attenuation curve of the polarization potential difference of the electrode along with the time through experiments, and corrects the potential difference data measured in the field by using the attenuation curve.

(2) When the time of the adjacent electrode participating in power supply is closer, the polarization potential difference can be offset through the recombination of the measured data of the adjacent electrode, and the polarization effect correction of the power supply electrode is realized.

(3) The method does not need to carry out special process improvement on the electrode, thereby reducing the manufacturing cost of the electrode; the arrangement sequence of the electrodes does not need to be re-planned through a complex algorithm, so that the utilization efficiency of the electrodes is improved; the influence of the polarization effect of the power supply electrode can be eliminated, the quality of detection/monitoring data is improved, and a data foundation is laid for high-precision interpretation of electrical prospecting results.

In this embodiment, an underground electrical monitoring engineering test is performed, monitoring data is acquired in a monopole-dipole working mode, and the monitoring electrode is made of stainless steel.

The mine water damage hidden danger electrical method monitoring system is deployed on a test working face, and the working face is more than 600m in length, so that 4 monitoring substations are accessed in the embodiment by expanding the actual condition; one measuring line is arranged on a bottom plate of the transport roadway (the electrode numbers are 1 to 60), and the other measuring line is arranged on a bottom plate of the return airway (the electrode numbers are 61 to 120). Each survey line is formed by splicing two substations, wherein one substation is connected with 32 channels, and the other substation is connected with 28 channels. In the acquisition process of the monitoring equipment, only odd electrodes participate in power supply, and all the electrodes can be used for signal measurement. In the data acquisition process, odd-numbered electrodes participate in power supply in sequence from small to large in number; the electrodes used for measurement sequentially measure signals according to the sequence of the numbers from small to large.

Fig. 17 is a graph of downhole measured data in this example, with the horizontal axis representing the number of receiving electrodes and the vertical axis representing the voltage values. The figure shows the potential difference curves measured by supplying power to No. 3 electrodes and measuring No. 61 to No. 120 electrodes in different time periods (data IDs: 20220315-001, 20220315-002, 20220315-012 and 20220315-013), wherein the original potential difference curve is in a zigzag form of ' low-high-low-high ' \ 8230; ' and the measured data are obviously influenced by the polarization potential difference of the power supply electrode.

In order to realize the polarization effect correction of the power supply electrode, the polarization effect of the stainless steel electrode is measured through experiments on the ground.

Firstly, the calibration coefficient of the stainless steel electrode is measured through experiments, and the method comprises the following specific steps:

experimental data measurement is carried out by adopting a single-pole-single-pole working mode; marking the tested electrode as a No. 1 electrode, wherein the No. 1 electrode is made of stainless steel; 3 auxiliary electrodes are prepared, and are marked as a No. 2 electrode, a No. 3 electrode and a No. 4 electrode in sequence, and the materials of the auxiliary electrodes are consistent with that of the No. 1 electrode.

According to a single-pole transmitting and receiving mode, the No. 1 electrode is arranged at the position of the measuring electrode, the No. 3 electrode is arranged at the position of the transmitting electrode, and the distance between the No. 1 electrode and the No. 3 electrode is about 100 m; the No. 2 electrode and the No. 4 electrode are arranged at the place which is kilometer away as the infinite electrodes, and a sufficient distance is ensured between the No. 2 electrode and the No. 4 electrode.

The No. 1 electrode and the No. 2 electrode form a measuring circuit, and the No. 3 electrode and the No. 4 electrode form a power supply circuit; supplying power to a power supply loop formed by the No. 3 electrode and the No. 4 electrode, wherein the No. 3 electrode is connected with the positive electrode of a power supply and the No. 4 electrode is connected with the negative electrode of the power supply during power supply; the power supply current is kept stable, and the power supply current and the power supply time are consistent with those of underground monitoring equipment; measuring potential difference by using a measuring loop formed by the No. 1 electrode and the No. 2 electrode, and recording the measured value as U ₀ The measurement value at this time is the measurement value before the electrode No. 1 is not polarized.

Replacing the No. 3 electrode with the No. 1 electrode, and installing the No. 1 electrode and the No. 4 electrode at the position of the transmitting electrode to form a power supply loop; supplying power to a power supply loop formed by the No. 1 electrode and the No. 4 electrode, wherein the No. 1 electrode is connected with the positive electrode of a power supply during power supply, and the No. 4 electrode is connected with the negative electrode of the power supply; the power supply current is kept stable, and the power supply current and the power supply time are consistent with those of underground monitoring equipment; no measurement is required at this point, and polarization of electrode # 1 is achieved by simply powering that electrode.

Installing the No. 1 electrode back to the original measuring electrode position, and installing the No. 3 electrode back to the original transmitting electrode position; the No. 1 electrode and the No. 2 electrode form a measuring circuit, and the No. 3 electrode and the No. 4 electrode form a power supply circuit; supplying power to a power supply loop formed by the No. 3 electrode and the No. 4 electrode, wherein the No. 3 electrode is connected with the positive electrode of a power supply during power supply, and the No. 4 electrode is connected with the negative electrode of the power supply; the power supply current is kept stable, and the power supply current and the power supply time are kept consistent with that of underground monitoring equipment; measuring potential difference by using a measuring loop formed by the No. 1 electrode and the No. 2 electrode, and recording the measured value as U ₁ The measurement value at this time is the measurement value after the electrode No. 1 is polarized.

Defining a correction coefficient alpha; contrast U ₁ And U ₀ Size of (1), if U ₁ Greater than U ₀ α =1; if U is ₁ Less than U ₀ ，α=-1。

Further, a polarization potential difference attenuation curve of the stainless steel electrode is determined through experiments, and the method comprises the following specific steps:

taking out the No. 1 electrode, standing for a long enough time until the polarization potential difference between the two ends of the electrode is reduced to 0; the No. 1 electrode is electrified again, and the power supply current and the power supply time are consistent with those of underground monitoring equipment; recording the moment of power failure as t ₀ (ii) a Continuously measuring the polarization potential difference between two ends of No. 1 electrode by using a potential difference measuring device, and recording the measuring time t _i And measured value

(ii) a Let t = t _i – t ₀ With time t as abscissa, polarization potential difference

Selecting a proper fitting formula according to the change characteristics of the polarization potential difference attenuation curve, and obtaining a functional relation U between the polarization potential difference and time through curve fitting _Polarization = f (t) The function expression can be used for calculating the power supply electrode after power failureA polarization potential difference at any moment.

The attenuation curve of the polarization potential difference of the stainless steel electrode shows that the attenuation of the polarization potential difference is fast in the early stage, and the attenuation speed is slow after a period of time. In this embodiment, the downhole electrical monitoring engineering test adopts an electrical perspective observation method to collect monitoring data, the time interval from the time when the electrode is used for power supply to the time when the electrode is used for signal measurement exceeds 1 hour, and at this time, the polarization potential difference enters a slow decay period.

Because the electrode materials used in the data acquisition process are the same, the influence of the polarization effect on different electrodes is theoretically consistent. The difference of the polarization potential differences of different electrodes is mainly caused by different attenuation time, under the condition that the time of the adjacent electrodes participating in power supply is closer, the difference of the attenuation time is smaller, the difference of the polarization potential differences is also relatively smaller, and at the moment, the polarization potential differences can be counteracted through the recombination of the measured data of the adjacent electrodes.

In the embodiment, in the process of acquiring the downhole test data, the time of the adjacent electrodes participating in power supply is closer, and the polarization potential difference of the adjacent electrodes is also closer, so that the polarization potential difference can be offset through the recombination of the measured data of the adjacent electrodes, and the polarization effect correction of the power supply electrodes is realized.

In this embodiment, a monopole-dipole working mode is adopted to collect monitoring data, only odd-numbered electrodes are used to supply power during the collection process, the influence of the polarization effect of the power supply electrode causes jagged abnormality of the measurement curve (as shown in fig. 17), and at this time, the influence of the polarization effect of the electrode can be eliminated by the superposition average of adjacent observation data, and the specific technical scheme is as follows:

the monopole-dipole observation data can be obtained by the combined superposition of the observation data of the adjacent electrodes on the basis of the monopole-monopole observation data, and the step of correcting the electrode polarization effect when only the odd-numbered electrodes are used for power supply is described on the basis of the monopole-monopole observation data, which is specifically as follows:

record the measurement data of the odd-numbered electrodes as

，i ₁ Is the number of the odd numbers,i ₁ =1,3,5, \8230;, and the measurement data of the even-numbered electrodes are recorded as

，i ₂ Is an even-numbered one and is,i ₂ =i ₁ +1; the odd-numbered electrodes participate in the power supply,

the even-numbered electrodes do not participate in power supply,

；

the extraction formula of the monopole-dipole observation data is as follows:

i ₁ =1，3，5，……；i ₂ =i ₁ +1；

when in use

，i ₁ =1,3,5, \8230; \8230atime, the feed electrode polarization effect correction formula is as follows:

。

the potential difference curve corrected by the polarization effect of the feeding electrode is shown in fig. 18, and the result in the graph shows that the sawtooth-shaped abnormality caused by the polarization of the feeding electrode is better suppressed.

The method corrects the polarization effect of the power supply electrode by a data processing method, effectively eliminates the influence of the polarization effect of the power supply electrode, improves the quality of monitoring data, and lays a data foundation for high-precision interpretation of electrical prospecting results. In the embodiment, special process improvement on the electrode is not needed, so that the manufacturing cost of the electrode is reduced; meanwhile, the arrangement sequence of the electrodes does not need to be re-planned through a complex algorithm, and the utilization efficiency of the electrodes is improved.

5. Correction for electrode uniformity

In the electric method monitoring system for the mine water damage hidden danger, disclosed by the invention, in the third step in the working process of the electric method monitoring data processor, the influence of electrode corrosion and shallow part nonuniformity in the monitoring data is corrected by using the electrode consistency correction module, and the specific steps are as follows:

step 1: the monitoring data corrected by the electrode polarization effect are sequenced according to the common transmitting point sequence and a common transmitting point curve is drawn, when the corroded electrode is used as a receiving electrode or when shallow uneven bodies exist near the receiving electrode, sawtooth-shaped abnormity occurs on the common transmitting point curve at the position of the electrode, the sawtooth-shaped abnormity of the common transmitting point curve is eliminated through smooth filtering, and the influence of corrosion of the receiving electrode and the shallow uneven bodies near the receiving electrode can be corrected at the same time.

Step 2: the monitoring data corrected by the electrode polarization effect are sequenced according to the sequence of the common receiving points, a common receiving point curve is drawn, when the corroded electrode is used as a transmitting electrode or when shallow uneven bodies exist near the transmitting electrode, sawtooth-shaped abnormity occurs on the common receiving point curve at the position of the electrode, the sawtooth-shaped abnormity of the common receiving point curve is eliminated through smooth filtering, and the influence of corrosion of the transmitting electrode and the shallow uneven bodies near the transmitting electrode can be corrected at the same time.

In the scheme, the monitoring data corrected by the electrode polarization effect are subjected to secondary sequencing and smooth filtering according to the sequence of the common transmitting point and the common receiving point, so that the acquisition error caused by electrode corrosion can be effectively eliminated, meanwhile, the influence of shallow unevenness can be eliminated, and the quality of the monitoring data is improved.

6. Inversion imaging with respect to mixed weight constraints

When the electric monitoring system for the mine water damage hidden danger carries out data acquisition, the data acquisition of two observation methods of an electric section and electric perspective is respectively carried out. However, due to the limitation of the underground observation space of the coal mine, although the electric method monitoring system for the water hazard potential of the coal mine improves the data acquisition density to a certain extent, the obtained electric reconstruction data volume is uneven in spatial distribution and still low in spatial average density, and the information contained in the observation data is limited, so that serious multi-solution exists when the inversion interpretation is carried out by using the electric reconstruction data volume. Aiming at the problems, an inversion method needs to be improved, proper prior information is applied to the resistivity inversion process for constraint, and the imaging resolution of the inversion result on the abnormal body space position and the spread range is improved.

Based on this, in the electrical method monitoring system for mine water damage hidden danger of the invention, step four in the working process of the electrical method monitoring data processor utilizes the mixed weight constraint inversion processing module to perform inversion imaging on the preprocessed monitoring data, and stores the imaging result into the memory, and the method specifically comprises the following processes:

step 1, according to the monitoring scheme, when the preprocessed monitoring data is processed in real time, a rectangular coordinate system is established by taking the central point of the working surface as the origin of coordinates,xthe direction is consistent with the direction of the working surface,ythe direction is consistent with the inclination of the working face,zthe direction is vertical to the working surface and faces downwards; and establishing an inversion grid for the observation area under the coordinate system.

Specifically, the inversion grid is established as follows:xdirection grid numerologyN _x ；yDirection grid numerologyN _y ；zThe number of direction grids is countedN _z (ii) a Total number of grid cellsN=N _x ×N _y ×N _z (ii) a Any grid cell number is given asi，j，k）（1≤i≤N _x ，1≤j≤N _y ，1≤k≤N _z ) (ii) a The coordinates of the center point of any grid cell are defined as (x _i ，y _j ，z _k ）（1≤i≤N _x ，1≤j≤N _y ，1≤k≤N _z ）。

And 2, determining the weight of the monitoring point for each grid unit.

Specifically, the resistivity information of each grid unit obtained through inversion reconstruction gradually attenuates along with the increase of the distance from the grid unit to the monitoring point, and the monitoring point information constraint is applied according to the characteristics to form the monitoring point weight. The weight of the monitoring point is generally a constant larger than 1, and the weight of the monitoring point of different grid units is gradually attenuated along with the increase of the distance from the grid unit to the monitoring point. Based on this, the method specifically comprises the following substeps:

step 21, recording the monitoring point weight of any grid cell as

Defining the watch point weight by:

assigning the initial value of the weight of the monitoring point of all grid cells to 1, namely, ordering

（i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z ) (ii) a Marking the number of the grid cell where the monitoring point is positioned as

And grid cell

The adjacent grid cells are marked as

(not including being marked as

Grid cell of) and

the adjacent grid cells are marked as

(excluding labels as

、

Grid cell of) and

the adjacent grid cells are marked as

(excluding labels as

、

、

Grid cell of) and

the adjacent grid cells are marked as

(not including being marked as

、

、

、

Grid cell of (c) and so on;

step 22, weight definition: order to

(C is a constant greater than 1), the weight of the monitoring points of the grid cells near the monitoring points is defined as follows:

and so on in turn;

，

，

，

waiting for the attenuation coefficient of the weight of the monitoring point, and generally taking a constant which is more than 0 and less than 1;

step 23, starting with the grid cells numbered (1, 1), searching for the grid cells in step 21 respectively

、

、

、

、

The weights of the monitoring points are assigned again according to the weight definition in the step 22; the method comprises the following steps: calculating the weight value to be given to the current grid unit according to the weight definition in the step 22wJudging the weight value to be given to the current grid cellwWhether to compare the initial value of the monitoring point weight of the grid cell

Big: if it is

Let us order

(ii) a If it is

，

The value of (c) is kept constant with the initial value of the weight. Through the process, the weight of the monitoring point of each grid unit can be ensured to meet the change rule that the weight values of different grid units gradually attenuate along with the increase of the distance from the grid unit to the monitoring point, and simultaneously the requirements of the change rule

（1≤i≤N _x ，1≤j≤N _y ，1≤k≤N _z ）。

And 3, determining the depth weight of each grid unit.

Specifically, in the direct current resistivity method, the electric field intensity has a characteristic of decreasing with depth, the resolution of the anomaly also decreases gradually with depth, and depth information constraint is applied according to the characteristic to form a depth weight. Depth weight and depth z of current grid cell _k （1≤k≤N _z ) In this regard, the depth weight values of different grid cells gradually decay as the depth at which the grid cell is located increases. Will be arbitrary latticeThe depth weight of the cell is noted

In the form as follows:

（i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z ）

wherein a is a constant greater than 0.

And 4, fusing the monitoring point weight and the depth weight of each grid unit to form a mixed weight. This step enables the simultaneous application of monitor point information constraints and depth information constraints to each grid cell.

Specifically, the mixing weight of any grid cell is noted as

The hybrid weights are formed by the product of the depth weights and the watch point weights, and are of the form:

（i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z ）。

and 5, constructing a diagonal matrix by taking the mixed weight of each grid unit as a diagonal element, and taking the diagonal matrix as a mixed weight matrix containing monitoring point information and depth information.

In particular, to

（i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z ) For diagonal elements, construct dimensions ofN×NDiagonal matrix W of _m ：

（1≤n≤N，1≤i≤N _x ，1≤j≤N _y ，1≤k≤N _z ）

In the formula

，W _m Is a hybrid weight matrix.

And 6, applying prior constraint information to the target function of the three-dimensional resistivity inversion by using the mixed weight matrix obtained in the step 5 to obtain the target function to which the prior constraint is applied.

Specifically, the inversion objective function is normalized for the three-dimensional resistivity in the following form:

in the formula:

residual errors of the actually measured data and the simulated observation data d are obtained;

is a resistivity model generated by inverse fitting;

is a reference model; w _d Is a data weight matrix;

is a model weight matrix;

is a regularization parameter, in which method a model weight matrix is passed

Applying prior information constraint to the objective function:

in the formula: w _m Is a hybrid weight matrix, which contains monitoring point information and depth information; i is an identity matrix; g _x ，G _y ，G _z Are respectively asx，y，zA gradient operator of direction;

is a model matrix

The weight of the diagonal element of (a);

are respectively asx，y，zGradient weight of direction. (gradient weights can be user-defined)

And 7, linearizing and minimizing the target function obtained in the step 6 to obtain a model updating formula applying mixed weight constraint. The model update formula is the inverse problem to be solved for applying the mixed weight constraint.

Specifically, the three-dimensional resistivity regularization inversion target function in step 6 is linearized and minimized to obtain the following model updating formula applying the mixed weight constraint:

wherein

In order to search for the parameters in a linear manner,

is a sensitivity matrix.

And 8, solving the inversion problem subjected to the mixed weight constraint by using an inversion algorithm, namely reconstructing the resistivity value of each grid unit in the observation area, and realizing three-dimensional inversion imaging of the underground low-density electrical reconstruction data volume of the coal mine.

Compared with the prior art, the method has the following beneficial effects:

the method has the advantages that the distribution range of the imaging result is more focused by applying the weight of the monitoring point, the resolution of the imaging result in the depth direction is effectively improved by applying the depth weight, the imaging resolution of the inversion result in the working face tendency and the depth direction is improved simultaneously by applying the mixed weight formed based on the weight of the monitoring point and the depth weight, and the resolution of the imaging result to deep anomaly is improved; the mixed weight constraint method is suitable for inversion imaging of the direct current resistivity method detection data obtained by adopting different working modes and observation systems under a coal mine, and is also suitable for inversion imaging of the direct current resistivity method detection data obtained by adopting different working modes and observation systems under the ground or well-ground combined condition.

To verify the feasibility and effectiveness of the method, the following tests were designed and tested:

separately applying no a priori information constraint (

) Applying watch point weights (

) Applying a depth weight of (

) And applying a mixing weight of (

) Four weight application methods are calculated. The length of the working face is 200m, the inclination width is 100m, electrodes are respectively arranged on a transport lane and a return airway of the working face, the distance between adjacent electrodes is 10m, the length of a measuring line is 200m, and each lane is respectively21 electrodes were arranged and fluoroscopy data was acquired using a dipole-dipole mode of operation. A low-resistance spherical abnormal body with the radius of 30m and the specific resistance of the spherical abnormal body exists below the bottom plate of the working surface

Resistivity of surrounding rock

. The case where the sphere burial depth h was 0m and 20m, respectively, was compared. When the imaging results are analyzed, the resistivity value is compared to the background resistivity: (

) When the variation amount of (2) is more than 10%, it is recognized as a resistivity abnormality, and the threshold value of the low-resistance abnormality is

。

Fig. 19 is a convergence curve of the inversion algorithm when different weights are applied when h =0m, where 1 is a convergence curve when prior information constraint is not applied, 2 is a convergence curve when a monitor point weight is applied, 3 is a convergence curve when a depth weight is applied, and 4 is a convergence curve when a mixture weight is applied. When prior information constraint is not applied and monitoring point weight is applied, the convergence curve is basically straight after about 5 iterations, the relative residual error cannot be further reduced after 10 iterations, and inversion is terminated. The descending speed of the convergence curve is faster when the depth weight and the mixed weight are applied, and after more than 10 iterations, the convergence curve basically approaches to a straight line parallel to the abscissa, which means that the attenuation of the data residual is extremely slow at the moment, and the inversion result cannot be further improved by more iterations. By contrast, the convergence of the algorithm is better when applying the depth weights and the blending weights, which is slightly better than applying the depth weights. In order to avoid invalid iterative calculation, a criterion for inversion stop is established according to the falling speed of the relative residual error when

（

Is a firstiThe relative residual after the sub-inversion iteration,

is as followsiThe relative residual before the sub-inversion iteration,iand more iterations are considered to be incapable of further improving the inversion result when the number is more than or equal to 1), and the inversion is stopped. The following model examples develop inversion calculations based on this criterion.

When h =0m, the spatial distribution range of the sphere is-30 m-x-30 m, -30 m-y-30m, 0 m-z-60 m, and the sphere center depth z =30m, the inversion result of the electrical perspective data when h =0m under different model additional weights is given in fig. 20-23, and the extreme value of the low-resistance area in the graph is defined as the center of the low-resistance area. FIG. 20 is the imaging result when h =0m and no prior information constraint is applied, and it can be seen from the figure that the low-resistance region spatial spread range is-20 m ≦ x ≦ 20m, -70m ≦ y ≦ 70m,0m ≦ z ≦ 50m, the low-resistance region center depth z =0m, and the spatial spread range and depth have large deviation with the model. FIG. 21 is the imaging result when the weight of the monitor point is applied when h =0m, and it can be seen that the spatial spread range (-20 m x 20m, -40m y 40m,0m z 50 m) of the low resistance region is closer to the model range, but the center depth z =0m of the low resistance region is more deviated from the model depth. FIG. 22 shows the imaging results when depth weighting is applied at h =0m, and it can be seen that the spread range (-20 m x 20 m) of the low-resistance region along the working plane is closer to the model range, the spread range (-60 m y 60 m) along the working plane is larger than the model range, the spread range (0 m z 60 m) in the depth direction substantially coincides with the model range, and the center depth z =30m of the low-resistance region substantially coincides with the model depth. FIG. 23 is an imaging result when the mixing weight is applied when h =0m, and it can be seen from the figure that the spread range (-30 m. Ltoreq. X.ltoreq.30 m) of the low resistance region along the working plane and the spread range (0 m. Ltoreq. Z.ltoreq.60 m) in the depth direction substantially coincide with the model range, the spread range (-50 m. Ltoreq. Y.ltoreq.50 m) along the working plane is larger than the model range, and the center depth z =30m of the low resistance region substantially coincides with the model depth. As can be seen by comparison, for the spherical model with h =0m, the deviation between the imaging result and the model is large when prior information constraint is not applied; the application of the monitoring point weight can effectively improve the resolution of the imaging result along the working face trend, but the improvement effect of the resolution in the depth direction is poor; applying depth weights is effective to improve the resolution of the imaging results in the depth direction, but substantially no improvement in resolution along the working plane trend; the mixed weight is applied to improve the resolution of the imaging result along the working face tendency and the depth direction at the same time, the strip-shaped abnormity along the working face tendency is improved to a certain degree, the improvement effect of the resolution along the depth direction is slightly better than that when the depth weight is applied, but the improvement effect of the resolution along the working face tendency is slightly lower than that when the monitoring point weight is applied.

When h =20m, the space distribution range of the sphere is-30 m-x-30 m, -30 m-y-30m, 20m-z-80 m, the sphere center depth z =50mFig. 24 to 27 show the inversion results of the electrical perspective data under different model additional weights when h =20 m. Fig. 24 is an imaging result when prior information constraint is not applied when h =20m, and it can be seen from the figure that the low resistance anomaly strength is weak, the low resistance region is not focused, obvious low resistance false anomaly occurs below the survey line, and the spread range (z is more than or equal to 0m and less than or equal to 30 m) in the depth direction of the low resistance region has a large deviation from the model range. FIG. 25 is the imaging result when the monitoring point weight is applied when h =20m, and it can be seen from the figure that the low resistance abnormal intensity is weaker, the spread range (-20 m x 20 m) of the low resistance region along the working surface and the spread range (-40 m y 40 m) along the working surface trend are closer to the model range, the spread range (0 m z 50 m) in the depth direction is smaller than the model range, and the center depth of the low resistance region is z =20m and is shallower than the model depth. FIG. 26 shows the imaging results when depth weighting is applied at h =20m, and it can be seen that the low resistance is enhanced significantly, the spread range (-20 m x 20 m) of the low resistance region along the working surface is closer to the model range, the spread range (-70 m y 70 m) along the working surface is larger than the model range, the spread range (10 m z 50 m) in the depth direction is smaller than the model range, and the center depth of the low resistance region is z =30m and shallower than the model depth. Drawing (A)27 is the imaging result when the mixing weight is applied when h =20m, and it can be seen from the figure that the low resistance is abnormally enhanced, the spread range (-30 m x 30 m) of the low resistance region along the working surface is basically consistent with the model range, the spread range (-50 m y 50 m) along the working surface is larger than the model range, the spread range (10 m z 70 m) in the depth direction is closer to the model range, and the center depth of the low resistance region is located at z =40m and closer to the model depth. As can be seen by comparison, for the spherical model with h =20m, the deviation between the imaging result and the model is large when the prior information constraint is not applied; the resolution of the imaging result along the working face trend can be improved by applying the monitoring point weight, but the improvement effect of the resolution in the depth direction is poor; applying depth weights may improve the resolution of the imaging results in the depth direction, but not along the working plane trend; the application of the mixed weight can obviously improve the resolution of the imaging result in the depth direction, the improvement effect is better than that when the depth weight is applied, the strip-shaped abnormity inclined along the working face is improved to a certain extent, but the low-resistance false abnormity appears below the measuring line. In addition, the low-resistance anomaly is remarkably enhanced when the depth weight is applied and the mixing weight is applied, wherein the strength of the low-resistance anomaly is maximum when the mixing weight is applied, and the method is favorable for improving the detection capability of the deep low-resistance anomaly structure.

Comprehensive comparison shows that the resolution of an imaging result in the depth direction can be effectively improved by applying the depth weight to the electric perspective data obtained by adopting a dipole-dipole working mode; the spreading range of the imaging result can be more focused by applying the weight of the monitoring point; the resolution capability of the imaging result on deep abnormity can be greatly improved by applying the mixed weight, and the strip abnormity inclined along the working surface is improved to a certain extent; when the depth of the sphere changes, the depth change of the sphere can be identified by the imaging results obtained by applying the depth weight and the mixed weight, wherein the reflection of the depth change by the imaging results obtained by applying the mixed weight is closer to the real change of the model.

Claims

1. The utility model provides a mine water damage hidden danger electrical method monitoring system which characterized in that includes at least:

the electrical method monitoring system controller (5) is used for sending a control instruction to the first electrical method monitoring substation (1) and the second electrical method monitoring substation (2) according to a set electrical method monitoring scheme;

the first L-shaped measuring line (3) and the second L-shaped measuring line (4) are respectively connected to a monitoring electrode group consisting of at least 4 monitoring electrodes and are used for enclosing a rectangle to enclose the working surface;

the first electrical method monitoring substation (1) and the second electrical method monitoring substation (2) are respectively connected with the first L-shaped measuring line (3) and the second L-shaped measuring line (4) and used for receiving a control instruction of an electrical method monitoring system controller (5), switching the monitoring electrodes according to the control instruction to obtain a combination of the transmitting electrode and the receiving electrode and controlling signal transmitting and receiving and acquisition of electrical method monitoring data;

the memory (6) is used for storing, processing and quality control the electric method monitoring data acquired by the first electric method monitoring substation (1) and the second electric method monitoring substation (2) in a control mode; the data processing device is used for storing the data processed by the electrical method monitoring data processor (7);

and the electrical monitoring data processor (7) is used for accessing the memory (6), carrying out observation voltage positive and negative attribute correction, electrode polarization effect correction, electrode consistency correction and mixed weight constraint inversion imaging on the electrical monitoring data taken out of the memory (6), and storing the processed data into the memory (6).

2. The mine water damage hidden danger electrical monitoring system of claim 1, characterized in that the first L-shaped measuring line (3) and the second L-shaped measuring line (4) are installed along the surrounding roadway of the working face; 32 monitoring electrodes are respectively connected to the first L-shaped measuring line (3) and the second L-shaped measuring line (4) according to the requirement of electrical monitoring, and the distance between the monitoring electrodes is 20 meters.

3. The electrical monitoring system for mine water damage hidden danger according to claim 1, characterized in that the material of the monitoring electrode is copper or stainless steel; the first L-shaped measuring line (3) and the second L-shaped measuring line (4) both adopt 32-core copper core explosion-proof cables.

4. The electrical method monitoring system for the mine water damage hidden danger according to claim 1 is characterized in that the first electrical method monitoring substation (1) and the second electrical method monitoring substation (2) adopt the same structure, and each electrical method monitoring substation at least comprises a substation controller (8), a communication module (9), an embedded central control module (10), an infinite control relay (11), a field source signal transmitting device (12), a switch matrix module (13), a signal acquisition device (14), a network communication module (15) and a multi-path low-noise isolation power module (16); the substation controller (8) is connected with the electric method monitoring system controller (5) and the signal acquisition device (14), and is connected with the embedded central control module (10) through the communication module (9); the embedded central control module (10) is respectively connected with the infinity control relay (11), the field source signal transmitting device (12) and the switch matrix module (13); the switch matrix module (13) is also respectively connected with a field source signal transmitting device (12), a signal collecting device (14) and a monitoring electrode group.

5. The mine water damage hidden danger electrical method monitoring system of claim 4, characterized in that the field source signal transmitting device (12) comprises a boost DC-DC module (17), a signal isolator (18) and a full-bridge conversion circuit (19); the boost DC-DC module (17) and the signal isolator (18) are respectively connected with a full-bridge conversion circuit (19), and the signal isolator (18) is connected with the embedded central control module (10); the full-bridge conversion circuit (19) is connected with the monitoring electrode gated by the switch matrix module (13).

6. The electric method monitoring system for mine water damage hidden danger according to claim 4, characterized in that the signal acquisition device (14) comprises a primary filtering and amplifying module (20), a power frequency filtering module (21), a secondary amplifying module (22), an optical coupling isolation module (23) and an AD acquisition module (24); the signal input end of the primary filtering amplification module (20) is used as the signal input end of the signal acquisition device (14), and the output end of the primary filtering amplification module (20) is connected with the signal input end of the power frequency filtering module (21); the signal output end of the power frequency filtering module (21) is connected with the signal input end of the secondary amplification module (22); the signal output end of the secondary amplification module (22) is connected with the signal input end of the AD acquisition module (24); the substation controller (8) is respectively connected with amplification factor control pins of a primary filtering amplification module (20) and a secondary amplification module (22) through an optical coupling isolation module (23); and the substation controller (8) is also respectively connected with a control end and a data output end of the AD acquisition module (24).

7. The electrical monitoring system for mine water damage hidden danger according to claim 6, characterized in that the power supply scheme of the multi-path low-noise isolation power supply module (16) is as follows: supplying a +/-9V power supply to the primary filtering amplification module (20), the power frequency filtering module (21) and the secondary amplification module (22); supplying +5V power to the switch matrix module (13), the substation controller (8), the optical coupling isolation module (23), the network communication module (15), the embedded central control module (10) and the communication module (9); and a +/-9V driving power supply and a +5V reference power supply are supplied to the AD acquisition module (24), and the +/-9V driving power supply and the +5V reference power supply are isolated.

8. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 4, characterized in that the flow of the control method of the electrical method monitoring system controller 5 is as follows:

step 1: numbering the monitoring electrodes: the number of monitoring electrodes in the monitoring electrode group on the first L-shaped measuring line (3)i ₁ ＝1,2,……,N ₁ (ii) a Number of monitoring electrode in monitoring electrode group of second L-shaped measuring line (4)i ₂ ＝N ₁ +1, N ₁ +2, ……, N ₁ +N ₂ Wherein, N is ₁ 、N ₂ Respectively a first L-shaped measuring line (3) and a second L-shaped measuring lineThe number of monitoring electrodes on the line (4);

and 2, step: according to a control instruction of an electrical monitoring system controller (5), executing the step 3 to acquire electrical profile data; step 4, collecting the electric perspective data;

and 3, step 3: acquiring a group of electrical profile data of a first electrical method monitoring substation (1) and a second electrical method monitoring substation (2);

and 4, step 4: acquiring a group of electric perspective data of a first electric method monitoring substation (1) and a second electric method monitoring substation (2);

and 5: the first electrical method monitoring substation (1) and the second electrical method monitoring substation (2) continuously receive the acquisition instruction sent by the electrical method monitoring system controller (5), circularly execute the step 3 to the step 4 to obtain multiple groups of required electrical profile data and electrical perspective data, and store the obtained data in a memory.

9. The mine water damage hidden danger electrical monitoring system of claim 8, wherein the step 3 specifically comprises the following steps:

step 31, the second electrical method monitoring substation (2) is standby, the substation controller (8) of the first electrical method monitoring substation (1) issues a control instruction, the embedded central control module (10) operates the infinite control relay (11), the field source signal transmitting device (12) and the switch matrix module (13) according to the control instruction, monitoring electrodes on the first L-shaped measuring line (3) are switched to select transmitting electrodes, and particularly the transmitting electrodes are selected from No. 1 to N ₁ The numbers are sequentially switched by 1 or 2; the selected transmitting electrode continuously transmits a direct-current square wave signal every time, in the transmitting process, monitoring electrodes except the current transmitting electrode on the first L-shaped measuring line (3) are switched to select receiving electrodes, specifically, 1 or 2 monitoring electrodes are sequentially switched from front to back according to serial numbers, the selected receiving electrodes receive signals every time, and the received signals are processed and collected through a signal collecting device (14); thereby obtaining the electrical profile data collected by the first electrical monitoring substation (1);

step 32, the first electric method monitoring substation (1) is standby, the second electric method monitoring substation: (2) The substation controller (8) issues a control instruction, the embedded central control module (10) operates the infinite control relay (11), the field source signal transmitting device (12) and the switch matrix module (13) according to the control instruction, and switches the monitoring electrodes on the second L-shaped measuring line (4) to select transmitting electrodes, specifically from N ₁ +1 starting backward to N ₁ +N ₂ The numbers are sequentially switched by 1 or 2; the selected transmitting electrode continuously transmits a direct-current square wave signal every time, in the transmitting process, monitoring electrodes except the transmitting electrode on the second L-shaped measuring line (4) are switched to select receiving electrodes, and specifically, 1 or 2 receiving electrodes are sequentially switched from front to back according to serial numbers; each time the selected receiving electrode receives signals, the received signals are processed and collected through a signal collecting device (14); thereby obtaining the electrical profile data collected by the second electrical monitoring substation (2).

10. The mine water damage hidden danger electrical monitoring system of claim 8, wherein the step 4 specifically comprises the following sub-processes:

step 41, a substation controller (8) of the first electrical monitoring substation 1 issues a control instruction, an embedded central control module (10) operates an infinite control relay (11), a field source signal transmitting device (12) and a switch matrix module (13) according to the control instruction, and switches monitoring electrodes on a first L-shaped measuring line 3 in the first electrical monitoring substation (1) to select transmitting electrodes, specifically from No. 1 to N ₁ The numbers are sequentially switched by 1 or 2; the selected transmitting electrode continuously transmits a pseudorandom multi-frequency signal every time, in the transmitting process, a substation controller (8) of a second electrical method monitoring substation (2) issues a control instruction, an embedded central control module (10) operates an infinite control relay (11), a field source signal transmitting device (12) and a switch matrix module (13) according to the control instruction, monitoring electrodes on a second L-shaped measuring line (4) in the second electrical method monitoring substation (2) are switched to select receiving electrodes, specifically, 1 or 2 receiving electrodes are sequentially switched from front to back according to sequence numbers, the selected receiving electrodes receive signals every time, and the received signals are all received signalsProcessing and collecting are carried out through a signal collecting device (14); obtaining electric perspective data collected by the second electric-method monitoring substation (2);

step 42, switching the monitoring electrode on the second L-shaped measuring line (4) in the second electrical method monitoring substation (2) to select the transmitting electrode, specifically from N ₁ Number to N ₁ + N ₂ The numbers are sequentially switched by 1 or 2; the selected transmitting electrodes continuously transmit pseudorandom multi-frequency signals every time, in the transmitting process, all monitoring electrodes on a first L-shaped measuring line (3) in a first electrical method monitoring substation (1) are switched to select receiving electrodes, specifically, 1 or 2 monitoring electrodes are sequentially switched from front to back according to serial numbers, the selected receiving electrodes receive signals every time, and the received signals are processed and collected through a signal collecting device (14); obtaining electric perspective data collected by a first electric method monitoring substation (1); a set of electrical perspective data of the first electrical monitoring substation (1) and the second electrical monitoring substation (2) is obtained therefrom.

11. The electrical monitoring system for mine water damage hidden danger according to claim 9 or 10, characterized in that the operations of switching the monitoring electrode to select the emitting electrode according to different working modes are as follows:

monopole emission mode: controlling an infinite control relay (11) corresponding to the electric monitoring substation to connect an output terminal B of a field source signal transmitting device (12) into an infinite electrode; controlling a switch matrix module (13) to connect an output terminal A of the field source signal transmitting device (12) to a selected one of the transmitting electrodes;

dipole emission mode: controlling a switch matrix module (13) of a corresponding electrical monitoring substation to connect the selected two transmitting electrodes into an output terminal A and an output terminal B of a field source signal transmitting device (12);

according to different working modes, the operations of switching the monitoring electrode to select the receiving electrode are respectively as follows:

monopole reception mode: controlling an infinite control relay (11) corresponding to the electric method monitoring substation, and connecting an input terminal N of a functional data acquisition module (12) into an infinite electrode; the switch matrix module (13) is operated, and an input terminal M of the signal acquisition device (14) is connected to a selected receiving electrode;

dipole reception mode: controlling a switch matrix module (13) corresponding to the electric method monitoring substation to connect two receiving electrodes selected from the monitoring electrode group into an input terminal M and an input terminal N of a signal acquisition device (14);

under the monopole-monopole working mode, switching into a monopole transmitting mode and a monopole receiving mode; under the monopole-dipole working mode, switching into a monopole transmission mode and a dipole receiving mode; and under the dipole-dipole working mode, the dipole transmitting mode and the dipole receiving mode are switched.

12. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 1, characterized in that the working process of the memory is as follows:

the method comprises the following steps: establishing a database in a memory, and predefining a table structure of various data;

step two: initializing through an electrical monitoring system controller (5), and storing initialization information into a corresponding table of a database;

step three: the electrical method monitoring system controller (5) accesses a database, acquires acquisition mode parameters, sends acquisition instructions to the first electrical method monitoring substation and the second electrical method monitoring substation according to the acquisition mode parameters, and the electrical method monitoring substations acquire monitoring data according to the acquisition instructions;

step four: when a first electric method monitoring substation (1) and a second electric method monitoring substation (2) carry out monitoring data acquisition, transmitting acquired original signals in real time and storing the acquired original signals into a database;

step five: under the electrical profile working mode, the storage performs corresponding signal processing on square wave signal amplitudes acquired by the first electrical method monitoring substation (1) and the second electrical method monitoring substation (2) by using a direct current square wave signal processing method, and stores the processing result in a database in real time;

step six: under an electric perspective working mode, the memory carries out corresponding signal processing on original full waveform signals acquired by the first electric method monitoring substation (1) and the second electric method monitoring substation (2) by using a multi-frequency data processing method, and processing results are stored in a database in real time;

step seven: the memory carries out quality evaluation and control on a group of complete original monitoring data through a quality control flow of electrical monitoring data, screens and marks monitoring data with qualified quality, marks the monitoring data with qualified quality as an unprocessed state, and stores a processing result in a database in real time;

13. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 1, characterized in that the workflow of the electrical method monitoring data processor is as follows:

the method comprises the following steps: configuring data preprocessing parameters and inversion parameters, wherein the data preprocessing parameters and the inversion parameters comprise data noise level, inversion grid parameters, inversion iteration times and a reference model, and the reference model is used for further prior information constraint on an inversion process;

step three: preprocessing the qualified monitoring data: firstly, correcting positive and negative attributes of monitoring data taken out of a memory by using an observation voltage positive and negative attribute correction module; correcting data abnormity caused by electrode polarization effect in the monitoring data by using an electrode polarization effect correction module; then, correcting the influence of electrode corrosion and shallow part nonuniformity in the monitoring data by using an electrode consistency correction module, and storing the data generated in the process into a memory;

step four: performing inversion imaging on the preprocessed monitoring data by using a mixed weight constraint inversion processing module, and storing an imaging result into a memory;

step five: and marking the monitoring data which completes the preprocessing and the inversion imaging as a processed state and storing the processed state in a memory.

14. The electrical mine water damage hazard monitoring system according to claim 1, further comprising a display connected to the electrical monitoring controller (5).

15. The electrical method monitoring system for mine water damage hidden danger according to claim 4, characterized by further comprising a safety control device for field source signal emission, wherein the safety control device for field source signal emission comprises a stepping motor driver (25), a stepping motor (26), a disc adjustable sliding rheostat (27), a MOSFET switch (28) and a sampling resistor (29); the stepping motor driver (25), the MOSFET switch (28) and the sampling resistor (29) are respectively connected with the embedded central control module (10); the stepping motor driver (25), the stepping motor (26) and the disc adjustable slide rheostat (27) are connected in sequence; the switch matrix module (13) is connected with a field source signal transmitting device (12); the sampling resistor (29), the MOSFET switch (28), the switch matrix module (13), the disc adjustable sliding rheostat (27) and the monitoring electrode group are sequentially connected end to form a transmitting loop.

16. The electrical monitoring system for mine water damage hidden danger according to claim 15, characterized in that the safety control method for field source signal emission realized by the safety control device for field source signal emission comprises the following steps:

the method comprises the following steps: placing the disc adjustable slide rheostat (27) in an initial state;

step two: setting voltage value U of field source emission signal _s And intrinsic safety current limiting value I _lim ；

step four: the embedded central control module (10) generates corresponding control signals to control the switch matrix module (13) to select one or a pair of electrodes in the monitoring electrode group, and the output terminal A and the output terminal B of the field source signal transmitting device (12) are correspondingly connected to be used as transmitting electrodes of field source signals;

step five: the field source signal transmitting device (12) starts a transmitting electrode to realize field source signal transmission according to a control signal generated by the embedded central control module (10); monitoring other electrodes in the electrode group to acquire electrical signal data;

step six: the embedded central control module (10) collects the voltage on the sampling resistor (29), calculates the voltage value Ur on the sampling resistor (29) in a signal amplification mode, and calculates the transmitting current value in the transmitting loop at the moment according to the voltage value Ur

Ur is in the unit V,10 is in the unit

，I _r The unit of (a);

step seven: the embedded central control module (10) transmits a current value I _r The intrinsic safety current limiting value I set in the step two _lim Comparing, if the emission current value I _r Less than intrinsic safety current limiting value I _lim If the embedded central control module (10) sends a PWM pulse control signal to the stepping motor driver (25), the stepping motor driver (25) controls the stepping motor (26) according to the received signal, the stepping motor (26) drives the cantilever of the disk adjustable slide rheostat (27) to rotate anticlockwise, and the access resistance R in the transmitting loop is reduced _t (ii) a If one has a hairRadio current value I _r Not less than intrinsic safety limiting value I _lim Executing the step ten;

step eight: returning to the step six until the transmitting current value I in the transmitting circuit _r Approximately equal to intrinsic safety limiting value I _lim Step nine is executed;

step nine: when the data acquisition is finished, the embedded central control module (10) controls the field source signal transmitting device (12) to stop transmitting the field source signal of the current transmitting electrode, meanwhile, the embedded central control module (10) generates a corresponding control signal to control the switch matrix module (13) to select another electrode or a pair of electrodes in the monitoring electrode group as the transmitting electrode of the field source signal and mark the transmitting electrode, the fifth step is returned until all the electrodes in the monitoring electrodes (9) are marked, and the transmitting process is finished;

step ten: the embedded central control module (10) sends a control logic signal to the MOSFET switch (28), so that a grid control signal of the MOSFET switch (28) is in a low level, a drain electrode and a source electrode are disconnected, namely, a transmitting loop is cut off, then the embedded central control module (10) sends a PWM (pulse width modulation) pulse control signal to the stepping motor driver (25), the stepping motor (26) is controlled to drive a cantilever of the disc adjustable sliding rheostat (27) to rotate clockwise, and an access resistor R in the transmitting loop is increased _t Up to a value of the transmission current I in the transmission circuit _r Approximately equal to the intrinsic safety current limiting value I _lim And returning to the step nine.

17. The electrical monitoring system for mine water damage hidden danger of claim 16, wherein in the second step, U is adopted _s =100V，I _lim =60mA。

18. The mine water damage hidden danger electrical method monitoring system of claim 6, wherein the mine electrical method multifunctional data acquisition and processing method using the system comprises the following steps:

step 1: the substation controller (8) of each electric method monitoring substation obtains the IP address distributed to the substation controller (8) by the electric method monitoring system controller (5) through the network communication module (15);

step 2: the electrical method monitoring system controller (5) selects a signal acquisition mode to be an electrical profile mode or an electrical perspective mode; when the working mode of the electrical section is selected, the superposition times and the amplification factor are set; when the electric perspective working mode is selected, setting sampling frequency, sampling time and amplification factor;

and step 3: the substation controller (8) receives a control command from the electrical method monitoring system controller (5), and configures a first-stage filtering amplification module (20), a second-stage amplification module (22) and an AD acquisition module (24) which accord with the set parameters in the second step;

and 4, step 4: according to different signal acquisition modes, the embedded central control module (10) generates different control logic signals, and a receiving electrode gated by the switch matrix module (13) is connected to the input end of the first-stage filtering amplification module (20);

and 5: when the data acquisition of the electric section method is carried out, a substation controller (8) captures a field source emission signal, namely a direct-current square wave signal, generates a trigger signal synchronous with the rising edge and the falling edge of the direct-current square wave signal and sends the trigger signal to an AD sampling module (22), the AD sampling module (22) starts to carry out data acquisition after receiving the trigger signal, acquires 20 values of a positive emission half period at the rising edge and 20 values of a negative emission half period at the falling edge, acquires electric section data according to the direct-current square wave signal, and executes step 6 to process the acquired electric section data;

and 6: carrying out superposition averaging on the acquired data to obtain a measured value, calibrating the acquired signal by using a square wave signal source, calculating to obtain an experimental value, obtaining an observation voltage coefficient according to the experimental value, and calculating to obtain a final observation voltage according to the measured value and the observation voltage coefficient;

and 7: the AD sampling module (22) performs electric perspective data acquisition according to the set sampling frequency and sampling time to obtain a full waveform file of the pseudo-random multi-frequency signal, and executes the step 8 to perform data processing;

and step 8: calibrating a full waveform file of the collected pseudo-random multi-frequency signals, if the field source emission signals are single-frequency waves, calculating calibration coefficients of the target frequency points, and calculating to obtain observation voltage values of the target frequency points; if the voltage value is a multi-frequency wave signal, obtaining a calibration coefficient of the multi-frequency point, calculating the voltage value of each main frequency point in the pseudo-random multi-frequency signal according to the calibration coefficient, eliminating data with the maximum deviation in the voltage values, and calculating the arithmetic mean value of the residual voltage values to obtain the final observed voltage value.

19. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 18, characterized in that the step 6 specifically comprises the following substeps:

(1) The measurement values are obtained by superposition averaging: collecting 20 values of a positive transmitting half period at a rising edge, deleting the first 2 values and deleting the last 2 values so as to eliminate the influence of a rising edge slope and a falling edge slope on data; then deleting the maximum value and the minimum value in the remaining 16 values to eliminate the influence of random interference on data; the remaining 14 values were then averaged and recorded as U _p (ii) a20 values of the negative half-transmission period are acquired at the falling edge, and are processed similarly and are marked as U _n (ii) a Thus, the voltage value of positive and negative half cycles in a low-frequency square wave period is obtained; take U = | (U) _p -U _n ) I/2 as a measured value S of one square wave period _Measuring (ii) a If the superposition times are more than 1, averaging the measured values of a plurality of square wave periods to obtain a measured value S _Measuring ；

(2) Calibrating the observation data coefficient by an electro-sectioning method: calibrating the electrical profile data acquired in the step 5 by using a square wave signal source; the absolute value of the amplitude of the square wave signal source is recorded as S ₀ And the average value of the absolute values of the amplitude values of the acquired square wave signals is recorded as S _{Experiment of the invention} The calculation formula of the observation voltage coefficient is as follows: δ = S ₀ /S _{Experiment of the invention} (ii) a Calibrating for multiple times by using square wave signal sources with different amplitudes, calculating observation voltage coefficients under different amplitudes, and calculating an average value of the observation voltage coefficients obtained by calibrating for multiple times to serve as a final observation voltage coefficient delta;

20. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 18, wherein the step 8 specifically comprises the following substeps:

if the field source transmits a signal as a single frequency wave, the frequency is recorded asf ¹ The target resolving frequency point corresponding to the received signal is the samef ¹ (ii) a Giving an amplitude of Z by means of a source of a sine wave signal ₀ At a frequency off ¹ The sine wave of (2) is input into a signal input end of a first-stage filtering and amplifying module (20); setting initial acquisition parameters, namely sampling frequency k =1200Hz, sampling duration tau =1s and amplification factor v =1, by a substation controller (8) to acquire data; obtaining the frequency response Z of the transmitted signal and the received signal by correlation detection ₁ Then target frequency pointf ¹ Is calibrated by the calibration factor

At a transmission frequency off ¹ When different sampling frequencies k, sampling duration tau and amplification factors v are selected for data acquisition, marking the target frequency point amplitude of the received signal as Zf ¹ Frequency point of the targetf ¹ The voltage value calculation formula is as follows:

；

(ii) a By adopting the calibration method of the single-frequency receiving signal,respectively obtain frequency points

Is calibrated by the calibration factor

；

B. According to the energy ratio of different frequency points in the multi-frequency wave signal, setting the weight of each frequency point as

The formula for calculating the voltage value of each main frequency point of the pseudorandom multi-frequency wave is as follows:

，

；

C. voltage values of different frequency points are superposed and averaged: and eliminating data with the largest deviation in the voltage values, and calculating the arithmetic mean value of the residual voltage values to obtain the final observed voltage value U.

21. The electrical mine water damage hazard monitoring system of claim 12, wherein the workflow of said memory comprises the seventh step of: the method comprises the following steps that the memory carries out quality evaluation and control on a group of complete original monitoring data through a quality control process of electrical monitoring data, and screening and marking monitoring data with qualified quality, and specifically comprises the following steps:

step 2: evaluation of raw data noise level: aiming at the current monitoring data processed in the step 1, carrying out Fourier transform on the full waveform data of each measuring point to obtain frequency spectrums with different frequencies, and further calculating the signal-to-noise ratio of the data of each measuring pointSNREvaluating the noise levels of the original monitoring data of different measuring points one by one, eliminating potential or potential difference data corresponding to unqualified measuring points in the group of evaluation units, and entering the next step for qualified data;

and step 3: evaluation of data stability spatially: regarding the current monitoring data processed in the step 2, taking a single transmitting electrode as a group of evaluation units, and if the reserved ratio of the measuring points of the single group of evaluation units after the step 2 is small, directly entering a step 4; otherwise, the potential of each measuring point is measuredV _i Or the potential difference deltaV _i Forming an actual measurement curve, taking a single transmitting electrode as a group of evaluation units, evaluating the stability of data from space, and then entering the current monitoring data processed in the step 2 into a step 4; at the moment, single group monitoring data processing is finished;

and 4, step 4: repeating the steps 1-3 to obtain a plurality of groups of monitoring data;

and 5: data stability was evaluated over time: and 4, selecting a plurality of monitoring data with adjacent acquisition time within a certain time period from the monitoring data obtained in the step 4, drawing a potential or potential difference change curve of the monitoring data of a single measuring point along with the time by taking the single measuring point as an evaluation unit, calculating the relative mean square error of each measuring point, and evaluating the data stability from the time according to the relative mean square error.

22. The electrical mine water damage hazard monitoring system of claim 21, wherein in step 1, the maximum threshold value of the emission current is setI _max Minimum threshold for maximum achievable emission current of the monitoring systemI _min Setting according to experience; when the emission current exceeds a threshold value, rejecting the electric potential or electric potential corresponding to the unqualified measuring point in the group of evaluation unitsDifference data; estimation by field testI _min The formula (c) is as follows:

I _min =A _min I _s /A _smin

wherein the content of the first and second substances,I _min a minimum threshold for emission current;A _min minimum signal distinguishable for the monitoring instrument;I _s is the emission current of the field test;A _smin the minimum potential or potential difference received by each measuring point in the field test.

23. The electrical mine water damage hazard monitoring system of claim 22 in which said maximum threshold of emitted current isI _max 80mA, minimum thresholdI _min And was 30mA.

24. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 21, characterized in that in the step 1: the stability of the transmit current is evaluated by the relative mean square error of the set of transmit currents, which is calculated as follows:

wherein the content of the first and second substances,m _I is the relative mean square error of the set of transmit currents,nin order to select the number of the measuring points corresponding to the transmitting electrode,I _j for the emission current data of a single station,

is composed ofnMean value of emission current data of each measuring point.

25. The electrical mine water damage hazard monitoring system of claim 24 wherein a threshold of the relative mean square error of the transmit current is set to 5% above which the transmit current is deemed unstable.

26. The electrical monitoring system for mine water damage hidden danger according to claim 21, characterized in that in step 2, the signal-to-noise ratio of the measuring points is calculated according to the following formula:

wherein the content of the first and second substances,V _signal a frequency spectrum of a transmission frequency obtained by performing Fourier transform on the full waveform data;V _noise the frequency spectrum of the noise of the frequency band near the transmitting frequency is obtained by carrying out Fourier transform on the full waveform data; the frequency band near the transmission frequency is a frequency band with a certain bandwidth and taking the transmission frequency as a center.

27. The electrical method monitoring system for mine water damage hidden danger according to claim 26, characterized in that the bandwidth of the frequency band near the emission frequency is determined according to the sampling frequency and the sampling duration, and at least comprises 10 frequency points; the signal-to-noise threshold for the data is 10dB.

28. The electrical monitoring system for mine water damage hidden danger according to claim 21, characterized in that in step 3, the measuring points of the single group of evaluation units are considered to be smaller when the reserved ratio after step 2 is smaller than a threshold value, and the threshold value is set to be in a range of 60% -80%.

29. The electrical mine water damage risk monitoring system of claim 21, wherein in the step 5, the plurality of substations with adjacent collection time within the certain time period are a plurality of sets of monitoring data under the same underground production environment condition within 24 hours or 48 hours.

30. The electrical monitoring system for mine water damage hidden danger according to claim 21, characterized in that in step 5, the calculation formula of the potential or potential difference of a single measuring point relative to the mean square error is:

wherein, the first and the second end of the pipe are connected with each other,m _s as the relative mean square error of the individual measured point potentials or potential differences,nfor the number of sets of monitoring data selected,S _i is the first of the measuring pointiThe group potential or potential difference monitors the data,

31. The electrical monitoring system for mine water damage hidden danger according to claim 13, wherein in the third step of the workflow of the electrical monitoring data processor, the positive and negative attributes of the monitoring data taken out from the memory are corrected by using the observed voltage positive and negative attribute correction module, and the method comprises the following steps:

step 1, marking a first group of monitoring data as initial monitoring data; marking the monitoring data obtained by subsequent repeated detection as subsequent monitoring data; each group of monitoring data is regarded as a group of independent monitoring data; when the initial monitoring data and the subsequent monitoring data exist, the continuous monitoring data are regarded as existing;

step 2, on the basis of the theoretical voltage curve, correcting the positive and negative attributes of the observed voltage value of the independent monitoring data by using the position relation of the measuring points of the transmitting electrode and the receiving electrode;

and 3, correcting the positive and negative attributes of the observed voltage value of the subsequent monitoring data by using a background elimination method.

32. The electrical method monitoring system for mine water damage hidden danger according to claim 31, wherein the step 2 specifically comprises the following substeps:

，NsThe total number of the emitter electrodes; the receiving electrodes are represented by M and N, and the coordinates are respectively expressed as

And

，Nrthe total number of receiving electrodes; the observed voltage value is recorded as

The corrected voltage value is recorded as

，

，

，

；

Monopole-dipole working mode transmitting-receiving measuring point position relationC _AMN The calculation formula of (c) is as follows:

wherein the content of the first and second substances,

；

；

the correction formula of the positive and negative properties of the monopole-dipole working mode observation voltage is as follows:

，

；

And

，

，

And

，

，

The corrected voltage value is recorded as

；

Dipole-dipole working mode transmitting-receiving measuring point position relationC _ABMN The calculation formula of (a) is as follows:

wherein:

；

；

；

being the distance between the transmitting electrode B and the receiving electrode N,

；

，

。

33. the electrical mine water hazard monitoring system of claim 31, wherein the specific operations of step 3 are as follows:

record initial monitoring data as

And the subsequent monitoring data is recorded as

，NtThe total amount of the monitoring data; recording the corrected monitoring data as D _k (ii) a Recording the simulation monitoring data of any uniform medium as D ^c The positive and negative voltage attribute correction formula of the subsequent monitoring data is as follows:

in the formula (I), the compound is shown in the specification,

。

34. the electrical method monitoring system for mine water damage hidden danger according to claim 13, wherein in step three of the workflow of the electrical method monitoring data processor, an electrode polarization effect correction module is used for correcting data abnormality caused by electrode polarization effect in monitoring data, and the specific steps are as follows:

step 1, measuring a correction coefficient of a tested electrode;

step 2, measuring a polarization potential difference attenuation curve of the tested electrode through an experiment;

step 3, selecting a proper fitting formula according to the change characteristics of the polarization potential difference attenuation curve obtained in the step 2, and obtaining a functional relation U between the polarization potential difference and time through curve fitting _{Polarization of} = f (t)；

Step 4, utilizing the functional relation U obtained in the step 3 _Polarization = f (t) The method is used for correcting the polarization effect of the power supply electrode which is made of the same material as the tested electrode, and comprises the following specific steps:

during the process of collecting the electrical monitoring data, the electrode used for supplying power is marked and the time from the electrode used for supplying power to the electrode used for supplying power is recordedDuration for signal measurement time intervalst(ii) a In the process of completing one-time complete data acquisition; every time an electrode participates in signal measurement, if the electrode is marked as a power supply electrode, the time interval from the time when the electrode is used for power supply to the time when the electrode is used for signal measurement needs to be updatedt；

(1) When a unipolar measurement is performed, the current electrode is noted as M, U being obtained according to step 3 _{Polarization of} = f (t) Calculating the polarization potential difference of the electrode M

The formula for correcting polarization effect is as follows:

in the formula (I), the compound is shown in the specification,U _measuring Representing the measurement data;U _{correction of} Data indicating that the measurement data is corrected; α represents a correction coefficient of the electrode;

(2) When dipole measurement is performed, the electrode near the positive side of the power supply is denoted as M, the electrode near the negative side of the power supply is denoted as N, and the reference U is given _Polarization = f (t) Respectively calculating the polarization potential difference of the electrode M and the electrode N

And

。

35. the electrical mine water damage hazard monitoring system of claim 34, wherein said step 2 comprises the operations of:

electrifying the electrode, stopping power supply, and recording the power-off time ast ₀ (ii) a Continuously measuring the polarization potential difference between two ends of the electrode by using a potential difference measuring device, and recording the measuring timet _i And measured value

36. The electrical monitoring system for mine water damage hidden danger according to claim 13, characterized in that in the third step in the work flow of the electrical monitoring data processor, the electrode polarization effect correction module is used to correct data abnormality caused by electrode polarization effect in the monitoring data, and in the monopolar-monopolar work mode, the specific steps are as follows:

step 1, under the condition that all electrodes participate in power supply in sequence, executing step 2 or step 3; when the electrodes are powered and all the electrodes participate in the measurement, executing the step 4;

step 2, recording the unipolar-unipolar measurement data

，

i=1,2,3,……,N-1；

step 3, respectively recording the unipolar measurement data corresponding to the two different power supply electrodes

And

，

；

i=1,2,3,……,N-1；

step 4, recording the measurement data of the odd-numbered electrodes as

and the even-numbered electrodes do not participate in power supply,

；

and extracting observation data of the monopole-dipole working mode, wherein the extraction formula is as follows:

i ₁ =1，3，5，……；i ₂ =i ₁ +1；

when in use

。

37. the electrical monitoring system for the hidden danger of mine water damage according to any one of claims 34 to 36, wherein the method for measuring the correction coefficient specifically comprises the following substeps:

step 11, adopting a monopole-monopole observation device to measure experimental data; marking the tested electrode as a No. 1 electrode, wherein the No. 1 electrode can be made of conductive materials such as stainless steel, copper, graphite and the like according to requirements; preparing 3 auxiliary electrodes, namely a No. 2 electrode, a No. 3 electrode and a No. 4 electrode in sequence, wherein the materials of the auxiliary electrodes are consistent with that of the No. 1 electrode;

step 12, according to the mode of unipolar transmission and unipolar reception, installing the No. 1 electrode at the position of the measuring electrode, and installing the No. 3 electrode at the position of the transmitting electrode, wherein the distance between the No. 1 electrode and the No. 3 electrode is about 100 m; taking the No. 2 electrode and the No. 4 electrode as infinite electrodes;

step 13, forming a measuring loop by the electrode No. 1 and the electrode No. 2, and forming a power supply loop by the electrode No. 3 and the electrode No. 4; supplying power to a power supply loop formed by the No. 3 electrode and the No. 4 electrode, wherein the No. 3 electrode is connected with the positive electrode of a power supply and the No. 4 electrode is connected with the negative electrode of the power supply during power supply; the power supply current is kept stable, and the power supply current and the power supply duration are consistent with those of actual exploration equipment; measuring potential difference by using a measuring loop formed by the No. 1 electrode and the No. 2 electrode, and marking the measured value as U ₀ The measured value at this time is the measured value before the electrode No. 1 is not polarized;

step 14, performing power supply polarization on the No. 1 battery: replacing the No. 3 electrode with the No. 1 electrode, and installing the No. 1 electrode and the No. 4 electrode at the position of the transmitting electrode to form a power supply loop; supplying power to a power supply loop formed by the No. 1 electrode and the No. 4 electrode, wherein the No. 1 electrode is connected with the positive electrode of a power supply during power supply, and the No. 4 electrode is connected with the negative electrode of the power supply; the power supply current is kept stable, and the power supply current and the power supply duration are consistent with those of actual exploration equipment; at the moment, the No. 1 electrode is polarized by supplying power to the No. 1 electrode;

step 15, installing the No. 1 electrode back to the original measuring electrode position, and installing the No. 3 electrode back to the original transmitting electrode position; the No. 1 electrode and the No. 2 electrode form a measuring circuit, and the No. 3 electrode and the No. 4 electrode form a power supply circuit; supplying power to a power supply loop formed by the No. 3 electrode and the No. 4 electrode, wherein the No. 3 electrode is connected with the positive electrode of a power supply and the No. 4 electrode is connected with the negative electrode of the power supply during power supply; the power supply current is kept stable, and the power supply current and the power supply time are consistent with those of actual exploration equipment; measuring potential difference by using a measuring loop formed by the No. 1 electrode and the No. 2 electrode, and marking the measured value as U ₁ The measured value at this time is the measured value after the electrode No. 1 is polarized;

step 16, defining a correction coefficient alpha; contrast U ₁ And U ₀ Size of (1), if U ₁ Greater than U ₀ α =1; if U is ₁ Less than U ₀ ，α=-1。

38. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 13, wherein in the third step in the working process of the electrical method monitoring data processor, the influence of electrode corrosion and shallow unevenness in the monitoring data is corrected by using the electrode consistency correction module, and the specific steps are as follows:

step 1: sequencing the monitoring data corrected by the electrode polarization effect according to the sequence of the common transmitting points, drawing a curve of the common transmitting points, and eliminating saw-tooth-shaped abnormity of the curve of the common transmitting points through smooth filtering;

step 2: and (3) sequencing the monitoring data corrected in the step (1) according to the sequence of the common receiving points, drawing a common receiving point curve, and eliminating sawtooth-shaped abnormity of the common receiving point curve through smooth filtering.

39. The electrical method monitoring system for mine water damage hidden danger as claimed in claim 13, wherein step four in the workflow of the electrical method monitoring data processor is that a mixed weight constraint inversion processing module is used to perform inversion imaging on the preprocessed monitoring data, and an imaging result is stored in a memory, and the method specifically comprises the following processes:

step 1, real-time processing is carried out on the preprocessed monitoring data, a rectangular coordinate system is established by taking the central point of the working surface as the origin of coordinates,xthe direction is consistent with the trend of the working surface,ythe direction is consistent with the inclination of the working face,zthe direction is vertical to the working surface and faces downwards; establishing an inversion grid for the observation area under the coordinate system;

the inversion grid is built as follows:xthe number of direction grids is countedN _x ；yThe number of direction grids is countedN _y ；zThe number of direction grids is countedN _z (ii) a Total number of grid cellsN=N _x ×N _y ×N _z (ii) a The arbitrary grid cell number is given by (i，j，k），1≤i≤N _x ，1≤j≤N _y ，1≤k≤N _z (ii) a The coordinates of the center point of any grid cell are defined as (x _i ，y _j ，z _k ），1≤i≤N _x ，1≤j≤N _y ，1≤k≤N _z ；

Step 2, determining the weight of the monitoring point for each grid unit

，i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z ；

Step 3, determining depth weight for each grid cell

，i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z ；

Step 4, fusing the monitoring point weight and the depth weight of each grid unit to form a mixed weight

；

Step 5, mixing weight of each grid unit

For diagonal elements, construct dimensions ofN×NThe diagonal matrix is used as a mixed weight matrix containing monitoring point information and depth information;

step 6, utilizing the mixed weight matrix obtained in the step 5 to apply prior constraint information to the target function of the three-dimensional resistivity inversion to obtain the target function to which the prior constraint is applied;

step 7, carrying out linearization and minimization on the objective function which is obtained in the step 6 and is applied with the prior constraint to obtain a model updating formula which is applied with the mixed weight constraint and is an inverse problem to be solved and applied with the mixed weight constraint;

and 8, solving the inversion problem subjected to the mixed weight constraint by using an inversion algorithm, namely reconstructing the resistivity value of each grid unit in the observation area, realizing three-dimensional inversion imaging of the underground low-density electrical reconstruction data volume of the coal mine, and storing the imaging result into a memory.

40. The electrical mine water damage hazard monitoring system of claim 39, wherein said step 2 comprises the substeps of:

step 21, recording the monitoring point weight of any grid cell as the monitoring point weight

，i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z (ii) a Marking the number of the grid cell where the monitoring point is positioned as

And grid cells

The adjacent grid cells are marked as

And is prepared by

The adjacent grid cells are marked as

And is and

the adjacent grid cells are marked as

And is and

the adjacent grid cells are marked as

And so on in turn;

step 22, monitoring point weight definition is carried out: order to

And C is a constant larger than 1, the monitoring point weights of the grid units near the monitoring points are sequentially defined as:

，

and so on;

，

，

，

waiting for the attenuation coefficient of the weight of the monitoring point, and taking a constant which is greater than 0 and less than 1;

and step 23, searching from the grid unit with the number of (1, 1), and respectively assigning the monitoring point weights of the grid unit in the step 21 according to the weight definition in the step 22.

41. The electrical mine water damage hazard monitoring system of claim 40, wherein said step 23 comprises the operations of:

calculating the weight value to be given to the current grid unit according to the weight definition in the step 22wJudging the weight value to be given to the current grid cellwWhether to compare the initial value of the monitoring point weight of the grid cell

Big: if it is

Let us order

(ii) a If it is

，

The value of (c) is kept constant at the initial value of the weight.

42. The electrical mine water disaster potential monitoring system as recited in claim 39 in which in said step 3, said depth weights are of the form:

，i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z (ii) a a is a constant greater than 0.

43. The mine water disaster hazard of claim 39The electrical monitoring system, wherein in step 4, the mixing weight is in the form of:

，i=1，……，N _x ；j=1，……，N _y ；k=1，……，N _z 。

44. the electrical mine hazard monitoring system of claim 39 wherein in step 5, said diagonal matrix is as follows:

，

in the formula, 1 is less than or equal ton≤N，1≤i≤N _x ，1≤j≤N _y ，1≤k≤N _z ；

。

45. The electrical mine water disaster condition monitoring system as recited in claim 39 in which in said step 6, said a priori constrained objective function is as follows:

in the formula (I), the compound is shown in the specification,

residual errors of the actually measured data and the simulated observed data d are obtained;

is a resistivity model generated by inverse fitting;

is a reference model; w _d Is a data weight matrix;

is a model weight matrix;

is the regularization parameter: w _m Is a mixing weight matrix; i is an identity matrix; g _x ，G _y ，G _z Are respectively asx，y，zA directional gradient operator;

is a model matrix

The weight of the diagonal element of (1);

are respectively asx，y，zGradient weight of direction.

46. An electrical method for monitoring hidden danger of mine water damage is characterized in that the electrical method for monitoring hidden danger of mine water damage is used for detecting and monitoring hidden danger of water damage, and comprises the following steps:

the method comprises the following steps: installing a system;

step two: information initialization: initializing information through an electrical monitoring system controller, and storing the initialized information into a corresponding table of a database of a memory;

step three: monitoring signal emission and collection: the electric method monitoring system controller sends transmitting and collecting instructions to the electric method monitoring substations according to the monitoring mode setting, and controls the working states of the two electric method monitoring substations; the two electric monitoring substations are matched to execute monitoring signal transmitting and collecting instructions to realize the transmission and collection of the monitoring signals and respectively finish the collection and storage of observation data by an electric sectioning method and an electric perspective method;

step four: signal processing: in the process of monitoring data acquisition, a memory is utilized to carry out real-time signal processing on the acquired original signals; under the working mode of the electrical profile, the collected direct-current square wave signals are processed in real time, and the converted observation voltage is stored in a memory in real time; under an electric perspective working mode, processing the acquired pseudo-random multi-frequency signals in real time, suppressing electromagnetic noise interference in the pseudo-random multi-frequency signals, and storing converted observation voltage into a memory in real time;

step five: and (3) cycle monitoring: the electro-sectioning observation data and the electro-perspective observation data jointly form a group of complete monitoring data, and after the group of complete monitoring data is acquired, the controller of the electro-monitoring system controls the two electro-monitoring substations to continue to acquire the next group of monitoring data;

step six: and (3) quality control: after completing a group of complete monitoring data acquisition and corresponding signal processing, the memory performs quality evaluation and control on the group of monitoring data, marks the monitoring data as qualified quality and unqualified quality, and stores the processing result in real time;

step seven: data processing and imaging: the electric method monitoring data processor is used for processing and inversion imaging of the monitoring data with qualified quality, and the subsequent data processing is not needed for the monitoring data with unqualified quality; in the process of monitoring data acquisition, an electrical monitoring data processor continuously accesses a memory, and when a group of monitoring data with qualified quality is detected, the group of monitoring data is preprocessed and inverted for imaging; preprocessing the qualified monitoring data: firstly, correcting positive and negative attributes of observation voltage on positive and negative attributes of monitoring data; correcting the electrode polarization effect of the data abnormality caused by the electrode polarization effect in the monitoring data; then, electrode consistency correction is carried out on the influence of electrode corrosion and shallow part nonuniformity in the monitoring data, inversion imaging is carried out on the monitoring data obtained by preprocessing, and the result obtained in the process and the final inversion imaging result are stored in a memory;

step eight: developing an electrical method for detecting the water hazard of the mine: before the stoping of the working face is not started, collecting multiple groups of complete monitoring data to suppress the influence of random noise on the data through repeated detection; superposing and averaging a plurality of groups of monitoring data to obtain a group of detection data, and storing the group of detection data in a memory; setting an electrical method monitoring data processor into a manual mode, and utilizing the electrical method monitoring data processor to carry out preprocessing and inversion imaging on the group of detection data obtained by superposition averaging, wherein the obtained imaging result is the background resistivity of the coal bed which is not influenced by coal mining activities; defining a resistivity abnormal area according to the background resistivity, and marking the corresponding area as a key area for later-stage monitoring; if a strong low-resistance abnormal region exists in the background resistivity, carrying out the ninth step;

step nine: and carrying out electric monitoring on the hidden danger of the mine water damage and giving out early warning on the potential water damage risk.

47. The method for electrically monitoring the hidden danger of mine water damage as claimed in claim 46, wherein the specific operation of the first step is as follows:

after the roadway of the working face is formed and before stoping is not started, a first L-shaped measuring line and a second L-shaped measuring line are arranged along the roadway around the working face to form a double-L-shaped full-surrounding array; the method comprises the following steps that a double-L-shaped full-surrounding array is connected into a first electric method monitoring substation and a second electric method monitoring substation, the two electric method monitoring substations are arranged at one end, close to a stop production line, outside a working face, and are connected into an underground power grid and a ring network; the electric method monitoring system controller, the memory and the electric method monitoring data processor are connected and installed on the electric method monitoring system controller; the two electric method monitoring substations are connected to an electric method monitoring system controller through a network; the electrical method monitoring system controller, the memory and the electrical method monitoring data processor carry out data interaction through an interface of the memory; and performing combined debugging on the ground and the underground monitoring system.

48. The electrical method for monitoring the hidden danger of mine water damage according to claim 46, characterized in that the concrete operations of the ninth step are as follows:

after the working face begins to adopt, carrying out real-time monitoring data acquisition and processing interpretation work; when the electrical method monitoring data processor is subjected to data preprocessing and inversion parameter configuration, setting the background resistivity obtained in the step eight as a reference model for performing mixed weight constraint inversion, and performing further prior information constraint on the inversion process; after data preprocessing and inversion parameter configuration are completed, setting an electrical method monitoring data processor into an automatic operation mode, and performing real-time processing imaging on monitoring data; when the monitoring imaging result is subjected to comparative analysis, paying attention to the resistivity change condition marked as a key area; when the resistivity is abnormally changed, early warning is given out on potential water damage risks.