Correction method for positive and negative properties of observed voltage

Abstract

The present invention discloses a method for correcting the positive and negative attributes of observed voltage: step 1, deploying an electrical monitoring system at an underground working face; step 2, using the electrical monitoring system to collect electrical monitoring data; when the collected monitoring data only has initial monitoring data, executing step 3 to correct the positive and negative attributes of the observed voltage value; when it is continuous monitoring data, executing step 3 for the initial monitoring data, and executing step 3 or 4 for the subsequent monitoring data to correct the positive and negative attributes of the observed voltage value; step 3, based on the theoretical voltage curve, using the positional relationship between the measuring points where the transmitting electrode and the receiving electrode are located to correct the positive and negative attributes of the observed voltage value for the independent monitoring data; step 4, using the background elimination method to correct the positive and negative attributes of the observed voltage value for the subsequent monitoring data. The present invention solves the technical problem in the prior art that the actual voltage value is negative while the observed voltage value is recorded as a positive value in the acquisition of electrical monitoring data.

Description

Technical Field

[0001] The present invention relates to a geophysical exploration data correction method, belongs to the field of geophysical exploration, and particularly relates to a method for correcting the positive and negative properties of an observed voltage. Background Art

[0002] Electrical monitoring reveals the temporal evolution of underground resistivity by deploying a fixed electrical exploration system in the target area for long-term repeated detection. This method is widely used in groundwater seepage monitoring, solute migration monitoring, pollution control process monitoring, landfill monitoring, permafrost area monitoring, landslide monitoring, water inrush monitoring during tunnel excavation, thermal diffusion monitoring, grouting effect monitoring, and coal mining face water hazard monitoring, and has achieved good geological results.

[0003] When electrical monitoring is applied underground in coal mines, data can be collected using methods such as single-line high-density electrical methods and dual-line electro-perspective methods, depending on the underground operating environment. Typical observation devices include monopole-monopole, monopole-dipole, and dipole-dipole. When observing in tunnels, to protect the monitoring cables, the observation electrodes are aligned with the measurement lines and are generally placed along the outer side of the tunnel. When observing in boreholes, due to space constraints, the observation electrodes are aligned with the measurement lines. During data collection, to suppress the strong electromagnetic noise interference in coal mines, a frequency signal is typically transmitted for full-waveform data acquisition. After signal processing, the observed voltage values ​​are obtained. These voltage values ​​are generally absolute values ​​of the actual voltage and cannot distinguish between positive and negative voltages.

[0004] Due to limited observation space in underground coal mines, in order to obtain sufficient observation data within this limited space, data collection is generally performed with one measuring point serving as the transmitting point, while all other measuring points serve as observation points. During data collection, the poles are generally moved from left to right, maintaining the same direction throughout the entire acquisition process. In this case, according to theoretical voltage curve analysis, for monopole-dipole and dipole-dipole observation devices, actual voltage values ​​within a certain range may appear negative, while the observed voltage values ​​are recorded as positive, failing to reflect the positive and negative properties of the actual voltage. When conducting electrical monitoring on the surface, acquisition control is generally implemented to avoid collecting observation data within the negative voltage range, or to avoid using observation devices that may produce negative voltage values. Furthermore, the apparent resistivity formula can be used to convert voltage values ​​into apparent resistivity values ​​to eliminate the influence of the positive and negative properties of the voltage.

[0005] However, for electrical monitoring in coal mines, limited observation space and the need to consider monitoring cable protection mean that the available data acquisition methods and observation devices are limited. Furthermore, for monopole-dipole and dipole-dipole observation devices, which offer relatively high detection resolution, the apparent resistivity curve calculated using the commonly used apparent resistivity formula will be distorted within a certain range where the voltage transitions from positive to negative. Therefore, processing and interpretation based on the apparent resistivity values ​​is not feasible. Directly processing and interpreting the voltage data collected using these data acquisition methods, which cannot distinguish between positive and negative voltages, using resistivity inversion can lead to false anomalies in the interpretation results, seriously misleading technicians' judgments. To avoid these issues, data processing typically removes data that is actually negative but recorded as positive. However, this processing method results in a loss of valid data, reducing detection resolution and, to a certain extent, impacting detection effectiveness. For monopole-dipole observation devices in particular, analysis of the theoretical voltage curve shows that the actual voltage values ​​at nearly half of the observation points are negative. Directly removing these data would result in a loss of half of the valid data, severely impacting detection effectiveness.

[0006] In summary, there is currently no effective solution to the problem that the actual voltage value is negative while the observed voltage value is recorded as positive in electrical monitoring data collection. Summary of the Invention

[0007] The present invention provides a method for correcting the positive and negative attributes of observed voltage during electrical monitoring data collection. The method mainly solves the technical problem in the prior art that the actual voltage value is negative while the observed voltage value is recorded as positive during electrical monitoring data collection.

[0008] The technical solution adopted by the present invention to solve its technical problem is:

[0009] A method for correcting the positive and negative properties of an observed voltage, comprising the following steps:

[0010] Step 1: deploy an electrical monitoring system at the underground working face;

[0011] Step 2: Collect electrical monitoring data using the electrical monitoring system; mark the first set of monitoring data obtained as initial monitoring data; mark the monitoring data obtained from subsequent repeated detections as subsequent monitoring data; each set of monitoring data is considered an independent set of monitoring data; when both initial monitoring data and subsequent monitoring data exist, it is considered that continuous monitoring data exists;

[0012] If the collected monitoring data is only the initial monitoring data, execute step 3 to correct the positive and negative attributes of the observed voltage value;

[0013] When the collected monitoring data is continuous monitoring data, perform step 3 on the initial monitoring data to correct the positive and negative attributes of the observed voltage value, and perform step 3 or step 4 on the subsequent monitoring data to correct the positive and negative attributes of the observed voltage value;

[0014] Step 3: Based on the theoretical voltage curve, the positional relationship between the transmitting electrode and the receiving electrode is used to correct the positive and negative properties of the observed voltage values ​​of the independent monitoring data;

[0015] Step 4: Use background elimination method to correct the positive and negative attributes of the observed voltage values ​​for subsequent monitoring data.

[0016] Furthermore, the electrical monitoring system includes a monitoring substation, a monitoring cable, and a monitoring electrode, wherein the monitoring electrode has transmitting and receiving functions.

[0017] Furthermore, step 3 includes the following sub-steps:

[0018] Step 31, for a monopole-dipole device, the transmitting electrode is a monopole and the receiving electrode is a dipole; the transmitting electrode is represented by A and the coordinates are Ns is the total number of transmitting electrodes; the receiving electrodes are represented by M and N, and their coordinates are recorded as and Nr is the total number of receiving electrodes; the observed voltage value is recorded as The corrected voltage value is recorded as U i,l,m ;

[0019] Position relationship between the transmitting and receiving points of the monopole-dipole device C AMN The calculation formula is as follows:

[0020] C AMN =r AN -r AM

[0021] Among them, r AM is the distance between the transmitting electrode A and the receiving electrode M,

[0022]

[0023] r AN is the distance between the transmitting electrode A and the receiving electrode N,

[0024]

[0025] The correction formula for the positive and negative properties of the voltage observed by the monopole-dipole device is as follows:

[0026]

[0027] Step 32, for a dipole-dipole device, the transmitting electrode is a dipole and the receiving electrode is a dipole; the transmitting electrode is represented by A and B, and the coordinates are marked as and Ns is the total number of transmitting electrodes; the receiving electrodes are represented by M and N, and their coordinates are recorded as and l=1,......,Nr-1,m=2,......,Nr,Nr is the total number of receiving electrodes; the observed voltage value is recorded as The corrected voltage value is recorded as U i,j,l,m ;

[0028] Position relationship between the transmitting and receiving points of the dipole-dipole device C ABMN The calculation formula is as follows:

[0029]

[0030] Among them, r AM is the distance between the transmitting electrode A and the receiving electrode M,

[0031]

[0032] r AN is the distance between the transmitting electrode A and the receiving electrode N,

[0033]

[0034] r BM is the distance between the transmitting electrode B and the receiving electrode M,

[0035]

[0036] r BN is the distance between the transmitting electrode B and the receiving electrode N,

[0037]

[0038] The correction formula for the positive and negative properties of the voltage values ​​observed by the dipole-dipole device is as follows:

[0039]

[0040] Among them, i=1,......,Ns-1, j=2,......,Ns, l=1,......,Nr-1, m=2,......,Nr.

[0041] Furthermore, the specific operations of step 4 are as follows:

[0042] The initial monitoring data is recorded as Subsequent monitoring data are recorded as Nt is the total number of monitoring data; the corrected monitoring data is recorded as D k , k=2,......,Nt; the simulated monitoring data of any uniform medium is recorded as D c , the voltage positive and negative attribute correction formula of subsequent monitoring data is as follows:

[0043]

[0044] Where, k=2,......,Nt.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] On the basis of the theoretical voltage curve, the independent monitoring data is corrected using the positional relationship of the transmitting and receiving measuring points, and the continuous monitoring data is corrected using the background elimination method. This can ensure that the positive and negative attributes of the corrected voltage value are consistent with the actual voltage value without losing valid observation data, greatly improving the detection resolution and the interpretation accuracy of the monitoring results.

[0047] The background elimination method is used to correct the continuous monitoring data, which can also eliminate the influence of system errors and background environment. Inversion imaging of the corrected monitoring data can highlight weak resistivity anomalies in the background of strong electrical inhomogeneity. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the observation system;

[0049] Figure 2 Theoretical voltage curve for simulating monitoring data for uniform media;

[0050] Figure 3 Observed voltage curves of initial monitoring data for the flume physical simulation;

[0051] Figure 4 Observed voltage curves for subsequent monitoring data from the flume physical simulation;

[0052] Figure 5 The voltage curve after the initial monitoring data of the water tank physical simulation is corrected using the positional relationship between the transmitting and receiving measuring points;

[0053] Figure 6 The voltage curve after correction is made using the positional relationship of the transmitting and receiving measuring points for subsequent monitoring data of the water tank physical simulation;

[0054] Figure 7 Voltage curve after background elimination method was used to correct the subsequent monitoring data of the water tank physical simulation;

[0055] Figure 8The inversion imaging results are not corrected for the subsequent monitoring data of the flume physical simulation;

[0056] Figure 9 The inversion imaging results after correction of the positional relationship between the transmitting and receiving measuring points are used for the subsequent monitoring data of the water tank physical simulation;

[0057] Figure 10 The inversion imaging results after correction of the subsequent monitoring data of the flume physical simulation using the background elimination method. DETAILED DESCRIPTION

[0058] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0059] The present invention provides a method for correcting the positive and negative properties of an observed voltage during electrical monitoring data collection, comprising the following steps:

[0060] Step 1: Design a monitoring plan based on the actual working conditions of the working face where electrical monitoring is required, and select an electrical monitoring system suitable for the working face while ensuring effective signal strength; deploy the electrical monitoring system at the underground working face according to the monitoring plan. The electrical monitoring system includes a monitoring substation, monitoring cables, and monitoring electrodes, where the monitoring electrodes have transmitting and receiving functions.

[0061] Step 2: Use the electrical monitoring system to collect monitoring data (electrical monitoring is to repeatedly detect the same target area, and each detection will obtain a set of monitoring data); mark the first set of monitoring data obtained as initial monitoring data; mark the monitoring data obtained from subsequent repeated detections as subsequent monitoring data; each set of monitoring data is regarded as an independent set of monitoring data; when both initial monitoring data and subsequent monitoring data exist, it is regarded as continuous monitoring data;

[0062] If the collected monitoring data is only the initial monitoring data, execute step 3 to correct the positive and negative attributes of the observed voltage value;

[0063] When the collected monitoring data is continuous monitoring data, perform step 3 on the initial monitoring data to correct the positive and negative attributes of the observed voltage value, and perform step 3 or step 4 on the subsequent monitoring data to correct the positive and negative attributes of the observed voltage value;

[0064] Step 3: Based on the theoretical voltage curve, the positional relationship between the transmitting electrode and the receiving electrode is used to correct the positive and negative properties of the observed voltage values ​​of the independent monitoring data. This step specifically includes the following sub-steps:

[0065] Step 31, for a monopole-dipole device, the transmitting electrode is a monopole and the receiving electrode is a dipole; the transmitting electrode is represented by A and the coordinates are Ns is the total number of transmitting electrodes; the receiving electrodes are represented by M and N, and their coordinates are recorded as and Nr is the total number of receiving electrodes; the observed voltage value is recorded as The corrected voltage value is recorded as U i,l,m ;

[0066] According to the theoretical voltage curve of the monopole-dipole device, the voltage range where the voltage will be negative is determined: when the pole direction is from left to right, the voltage is negative when the receiving point is on the left side of the transmitting point, and positive when the receiving point is on the right side of the transmitting point. The positive and negative properties of the voltage value are related to the relative positions of the transmitting and receiving measuring points. The position relationship C of the transmitting and receiving measuring points of the monopole-dipole device is AMN The calculation formula is as follows:

[0067] C AMN =r AN -r AM

[0068] Among them, r AM is the distance between the transmitting electrode A and the receiving electrode M,

[0069]

[0070] r AN is the distance between the transmitting electrode A and the receiving electrode N,

[0071]

[0072] The correction formula for the positive and negative properties of the voltage observed by the monopole-dipole device is as follows:

[0073]

[0074] Step 32, for a dipole-dipole device, the transmitting electrode is a dipole and the receiving electrode is a dipole; the transmitting electrode is represented by A and B, and the coordinates are marked as and Ns is the total number of transmitting electrodes; the receiving electrodes are represented by M and N, and their coordinates are recorded as and Nr is the total number of receiving electrodes; the observed voltage value is recorded as The corrected voltage value is recorded as U i,j,l,m ;

[0075] The voltage range where negative voltage occurs is determined based on the theoretical voltage curve of the dipole-dipole device: when the pole direction is from left to right, all voltage values ​​are negative when collecting data using the single-line high-density electrical method; when collecting data using the dual-line electro-perspective method, the voltage value is positive within the sector directly opposite the transmitting point, and negative outside the sector. The extent of the sector is related to the spacing and angle between the measuring lines; the positive and negative properties of the voltage value are related to the relative positions of the transmitting and receiving measuring points; the position relationship between the transmitting and receiving measuring points of the dipole-dipole device C ABMN The calculation formula is as follows:

[0076]

[0077] Among them, r AM is the distance between the transmitting electrode A and the receiving electrode M,

[0078]

[0079] r AN is the distance between the transmitting electrode A and the receiving electrode N,

[0080]

[0081] r BM is the distance between the transmitting electrode B and the receiving electrode M,

[0082]

[0083] r BN is the distance between the transmitting electrode B and the receiving electrode N,

[0084]

[0085] The correction formula for the positive and negative properties of the voltage values ​​observed by the dipole-dipole device is as follows:

[0086]

[0087] When the running direction is different from the above direction, the positive and negative attribute ranges of the voltage value will change, but the calculation formulas of step 41 and step 32 are still applicable.

[0088] Step 4: Use the background elimination method to correct the positive and negative properties of the observed voltage values ​​for the subsequent monitoring data. The specific operations are as follows:

[0089] The monitoring data contains the observed voltages at different measuring points and is a one-dimensional vector. The initial monitoring data is recorded as Subsequent monitoring data are recorded as Nt is the total number of monitoring data; the corrected monitoring data is recorded as D k(k=2,......,Nt); the simulated monitoring data of any uniform medium is recorded as D c The simulated monitoring data is obtained by calculating the theoretical formula of the electric field distribution of the point source. The positive and negative attributes of the voltage value are completely consistent with the theoretical voltage curve. The correction formula for the positive and negative attributes of the voltage of the subsequent monitoring data is as follows:

[0090]

[0091] pass Can eliminate the influence of background environment, and at the same time Make D k With D c The positive and negative attributes of the elements in are exactly the same.

[0092] The method of using the background elimination method in step 4 to correct the positive and negative properties of the observed voltage of the continuous monitoring data is applicable to different observation methods and different observation devices.

[0093] Example:

[0094] In order to verify the feasibility and effectiveness of the method of the present invention, a water tank physical simulation test was carried out in this embodiment, and monitoring data were collected using an electro-perspective observation method and a dipole-dipole observation device. Figure 1 As shown, two electrode holders are installed in mirror-image fashion, oriented around the centerline of the flume, with a spacing of 80 cm between them. Each holder holds 30 electrodes, with a spacing of 6 cm between them. Electrodes on survey line 1 are numbered 1 to 30, while electrodes on survey line 2 are numbered 31 to 60. The observation system has a scale similarity of 1:250, simulating a working face with a dip width of 200 m and a strike length of 435 m. Three metal objects, also modeled at a scale similarity of 1:250, are placed beneath the water surface to simulate low-resistance anomalies.

[0095] In the physical model, an iron rod measuring 8 cm × 40 cm was placed vertically, with its center facing electrode 8 on survey line 1. The horizontal distance from its center to survey line 1 was 20 cm, and the depth from its top surface to the water surface was 1 cm. The iron rod remained fixed throughout the experiment. An aluminum plate measuring 3 cm × 13 cm × 45 cm was placed horizontally, with its center facing electrode 16 on survey line 1. The horizontal distance from its center to survey line 2 was 20 cm, and the initial depth from its top surface to the water surface was 28 cm. The aluminum plate gradually rose throughout the experiment to simulate the upward development of water-conducting geological structures. A copper rod measuring 5 cm × 20 cm was placed horizontally, with its center facing electrode 24 on survey line 1. The horizontal distance from its center to survey line 1 was 40 cm, and the depth from its top surface to the water surface was 4 cm. The copper rod remained fixed throughout the experiment.

[0096] according to Figure 1The monitoring system shown in the figure adopts the electro-perspective observation method and the dipole-dipole observation device. The theoretical formula of electric field distribution is used to calculate the theoretical observation data when the uniform dielectric resistivity is 200Ω.m. The simulated monitoring data is obtained. The voltage curve is shown in the figure below. Figure 2 The voltage curves corresponding to electrodes 1 to 30 on the left side of the figure are the voltage curves obtained by transmission through measurement line 2 and reception through measurement line 1. The voltage curves corresponding to electrodes 31 to 60 on the right side of the figure are the voltage curves obtained by transmission through measurement line 1 and reception through measurement line 2. The positive and negative properties of the voltage values ​​in the figure are completely consistent with the theoretical voltage curve. The voltage values ​​are positive within the sector-shaped area directly opposite the transmission point, and negative values ​​are outside the sector-shaped area.

[0097] The observed voltage curve of the initial monitoring data of the water tank physical simulation is as follows Figure 3 As shown, the aluminum plate was not lifted at this time, and its similar depth was 70m. The voltage curves corresponding to electrodes 1 to 30 on the left side of the figure are the voltage curves obtained by transmission through measuring line 2 and reception through measuring line 1. The voltage curves corresponding to electrodes 31 to 60 on the right side of the figure are the voltage curves obtained by transmission through measuring line 1 and reception through measuring line 2. The voltage curves in the figure are drawn based on data observed by the monitoring equipment, and the curves show that the observed voltage values ​​are all positive.

[0098] The observed voltage curve of the subsequent monitoring data of the water tank physical simulation is as follows Figure 4 As shown, the aluminum plate is lifted 50 meters, and its similar depth is 20 meters. The voltage curves corresponding to electrodes 1 to 30 on the left side of the figure are the voltage curves generated by transmission through measuring line 2 and reception through measuring line 1. The voltage curves corresponding to electrodes 31 to 60 on the right side of the figure are the voltage curves generated by transmission through measuring line 1 and reception through measuring line 2. The voltage curves in the figure are drawn based on data observed by the monitoring equipment, and the curves show that the observed voltage values ​​are all positive.

[0099] contrast Figure 2 、 Figure 3 and Figure 4 visible, Figure 3 and Figure 4 The voltage curve observed by the monitoring equipment does not have Figure 2 The voltage curve obtained through theoretical calculation is smooth, while the voltage data observed by the monitoring equipment contains the influence of system errors and background environment.

[0100] According to step 4 of the method of the present invention, the position relationship between the transmitting and receiving measuring points is used to Figure 3 The initial monitoring data of the water tank physical simulation shown is corrected for the positive and negative properties of the observed voltage.

[0101] For a dipole-dipole device, the transmitter is a dipole and the receiver is a dipole; let A and B represent the transmitter electrodes, and the coordinates are (i = 1, ..., 29 when line 1 is launched; i = 31, ..., 59 when line 2 is launched) and (j=2,......,30 when measuring line 1 is transmitting; j=32,......,60 when measuring line 2 is transmitting); the receiving electrodes are represented by M and N, and their coordinates are recorded as (l=1,......,29 when receiving on line 1; l=31,......,59 when receiving on line 2) and (When measuring line 1 receives, m=2,......,30; when measuring line 2 receives, m=32,......,60); record the observed voltage value as The corrected voltage value is recorded as U i,j,l,m Based on the theoretical voltage curve of the dipole-dipole device, determine the range where the voltage will be negative: when running from left to right, when collecting data using the dual-line electroscopic method, the voltage value in the sector directly opposite the transmitting point is positive, and the voltage value outside the sector is negative. The range of the sector is related to the spacing and angle between the measuring lines. The positive and negative properties of the voltage value are related to the relative positions of the transmitting and receiving measuring points. The formula for calculating the positional relationship of the transmitting and receiving measuring points of the dipole-dipole device is as follows:

[0102]

[0103]

[0104] The correction formula for the positive and negative properties of the voltage values ​​observed by the dipole-dipole device is as follows:

[0105]

[0106] Where: when measuring line 1 transmits and measuring line 2 receives: i=1,......,29,j=2,......,30,l=31,......,59,m=32,......,60;

[0107] When measuring line 2 transmits and measuring line 1 receives: i = 31,......,59, j = 32,......,60, l = 1,......,29, m = 2,......,30.

[0108] The initial monitoring data of the water tank physical simulation is observed using the position relationship of the transmitting and receiving measuring points. The voltage curve after the voltage positive and negative attributes are corrected is as follows: Figure 5As shown. The voltage curves corresponding to electrodes 1 to 30 on the left side of the figure are the voltage curves obtained by transmitting through measuring line 2 and receiving through measuring line 1; the voltage curves corresponding to electrodes 31 to 60 on the right side of the figure are the voltage curves obtained by transmitting through measuring line 1 and receiving through measuring line 2; the voltage curves in the figure are obtained by correcting the initial monitoring data of the water tank physical simulation using the positional relationship of the transmitting and receiving measuring points. The positive and negative properties of the corrected voltage values ​​are basically consistent with the theoretical voltage curves. The voltage value is positive in the fan-shaped area directly opposite the transmitting point, and negative values ​​appear outside the fan-shaped area; there is no voltage curve in the figure. Figure 2 The voltage curve obtained by theoretical calculation is smooth, but the data corrected by the positional relationship between the transmitting and receiving measuring points still contains the influence of system errors and background environment.

[0109] According to step 4 of the method of the present invention, the position relationship between the transmitting and receiving measuring points is used to Figure 4 The water tank physical simulation shown is used to correct the positive and negative properties of the observed voltage using subsequent monitoring data.

[0110] For a dipole-dipole device, the transmitter is a dipole and the receiver is a dipole; let A and B represent the transmitter electrodes, and the coordinates are (i = 1, ..., 29 when line 1 is launched; i = 31, ..., 59 when line 2 is launched) and (j=2,......,30 when measuring line 1 is transmitting; j=32,......,60 when measuring line 2 is transmitting); the receiving electrodes are represented by M and N, and their coordinates are recorded as (l=1,......,29 when receiving on line 1; l=31,......,59 when receiving on line 2) and (When measuring line 1 receives, m=2,......,30; when measuring line 2 receives, m=32,......,60); record the observed voltage value as The corrected voltage value is recorded as U i,j,l,m Based on the theoretical voltage curve of the dipole-dipole device, determine the range where the voltage will be negative: when running from left to right, when collecting data using the dual-line electroscopic method, the voltage value in the sector directly opposite the transmitting point is positive, and the voltage value outside the sector is negative. The range of the sector is related to the spacing and angle between the measuring lines. The positive and negative properties of the voltage value are related to the relative positions of the transmitting and receiving measuring points. The formula for calculating the positional relationship of the transmitting and receiving measuring points of the dipole-dipole device is as follows:

[0111]

[0112] The correction formula for the positive and negative properties of the voltage values ​​observed by the dipole-dipole device is as follows:

[0113]

[0114] Among them: when survey line 1 transmits and survey line 2 receives: i = 1,......,29, j = 2,......,30, l = 31,......,59, m = 32,......,60; when survey line 2 transmits and survey line 1 receives: i = 31,......,59, j = 32,......,60, l = 1,......,29, m = 2,......,30.

[0115] The subsequent monitoring data of the water tank physical simulation is observed using the position relationship of the transmitting and receiving measuring points. The voltage curve after the voltage positive and negative attributes are corrected is shown in the attached figure. Figure 6 As shown. The voltage curves corresponding to electrodes 1 to 30 on the left side of the figure are the voltage curves obtained by transmitting through measuring line 2 and receiving through measuring line 1; the voltage curves corresponding to electrodes 31 to 60 on the right side of the figure are the voltage curves obtained by transmitting through measuring line 1 and receiving through measuring line 2; the voltage curves in the figure are obtained by correcting the subsequent monitoring data of the water tank physical simulation using the positional relationship of the transmitting and receiving measuring points. The positive and negative properties of the corrected voltage values ​​are basically consistent with the theoretical voltage curve. The voltage value is positive in the sector area directly opposite the transmitting point, and negative values ​​appear outside the sector area; the voltage curve shape in the figure does not have Figure 2 The voltage curve obtained by theoretical calculation is smooth, but the data corrected by the positional relationship between the transmitting and receiving measuring points still contains the influence of system errors and background environment.

[0116] According to step 5 of the method of the present invention, the background elimination method is used to Figure 4 The water tank physical simulation shown is used to correct the positive and negative properties of the observed voltage using subsequent monitoring data.

[0117] The monitoring data contains the observed voltages at different measuring points and is a one-dimensional vector. The initial monitoring data is recorded as Subsequent monitoring data are recorded as Nt is the total number of monitoring data; the corrected monitoring data is recorded as D k (k=2,......,Nt); the simulated monitoring data of any uniform medium is recorded as D c The simulated monitoring data is obtained by calculating the theoretical formula of the electric field distribution of the point source. The positive and negative attributes of the voltage value are completely consistent with the theoretical voltage curve. The correction formula for the positive and negative attributes of the voltage of the continuous monitoring data is as follows:

[0118]

[0119] pass It can eliminate the influence of background environment and have Make D k With D c The positive and negative attributes of the elements in are exactly the same.

[0120] The method of correcting the positive and negative properties of the observed voltage of continuous monitoring data using a background elimination method is applicable to different observation methods and different observation devices.

[0121] In this embodiment, Figure 2 The simulated monitoring data shown is denoted as D c ,Will Figure 3 The initial monitoring data of the water tank physical simulation is recorded as Will Figure 4 The subsequent monitoring data of the water tank physical simulation shown is recorded as According to step 5 of the method of the present invention, the background elimination method is used to Figure 4 Subsequent monitoring data from the flume physical simulation shown The calculation formula for correcting the positive and negative properties of the observed voltage is as follows:

[0122]

[0123] D2 is the background elimination method Figure 4 Subsequent monitoring data from the flume physical simulation shown The result after correction of the positive and negative properties of the observed voltage.

[0124] The background elimination method in step 5 of the method of the present invention is used to observe the subsequent monitoring data of the water tank physical simulation. The voltage curve after the voltage positive and negative attributes are corrected is as follows: Figure 7 As shown. The voltage curves corresponding to electrodes 1 to 30 on the left side of the figure are the voltage curves obtained by transmitting through line 2 and receiving through line 1; the voltage curves corresponding to electrodes 31 to 60 on the right side of the figure are the voltage curves obtained by transmitting through line 1 and receiving through line 2; the voltage curves in the figure are obtained by correcting the subsequent monitoring data of the water tank physical simulation using the background elimination method. The positive and negative properties of the corrected voltage values ​​are basically consistent with the theoretical voltage curve. The voltage value is positive in the fan-shaped area opposite the emission point, and negative values ​​appear outside the fan-shaped area; the shape of the voltage curve in the figure is consistent with the theoretical voltage curve. Figure 2 The voltage curve obtained by theoretical calculation is as smooth as the one in the figure. The influence of systematic error and background environment in the data corrected by background elimination method is well eliminated.

[0125] The inversion imaging results of the subsequent monitoring data of the water tank physical simulation without correction are as follows: Figure 8 The imaging results in the figure show that strong false anomalies appear at the left and right ends of the observation area, while the aluminum plate anomaly in the middle and the small-scale iron and copper rod anomalies on the left and right sides are basically not reflected in the imaging results.

[0126] According to step 4 of the method of the present invention, the inversion imaging result after the positive and negative attributes of the observed voltage are corrected by using the position relationship of the transmitting and receiving measuring points for the subsequent monitoring data of the water tank physical simulation is as follows: Figure 9The imaging results in the figure show that due to the influence of the background environment such as the water tank boundary effect, false anomalies appear near the boundary of the observation area. The aluminum plate anomaly in the center is weakly reflected in the imaging results, and the small-scale iron and copper rod anomalies on the left and right sides are not reflected in the imaging results.

[0127] According to step 5 of the method of the present invention, the inversion imaging result after the positive and negative attributes of the observed voltage are corrected by using the background elimination method for the subsequent monitoring data of the water tank physical simulation is as follows: Figure 10 The imaging results in the figure show that the influence of the background environment, such as the water tank boundary effect, has been eliminated. The aluminum plate anomaly in the middle is strongly reflected in the imaging results, as are the small-scale iron and copper rod anomalies on the left and right sides.

[0128] In summary, it can be seen that on the basis of the theoretical voltage curve, the positional relationship between the transmitting and receiving measuring points is used to correct the independent monitoring data, and the background elimination method is used to correct the continuous monitoring data. This can ensure that the positive and negative attributes of the corrected voltage value are consistent with the actual voltage value without losing the effective observation data, thereby greatly improving the detection resolution and the interpretation accuracy of the monitoring results. The background elimination method is used to correct the subsequent monitoring data, and the influence of systematic errors and background environment can also be eliminated. Inversion imaging of the corrected monitoring data can highlight weak resistivity anomalies in the background of strong electrical inhomogeneity.

Claims

1. A method for correcting the positive and negative properties of an observed voltage, characterized in that: The specific steps include: Step 1: deploy an electrical monitoring system at the underground working face; Step 2: Collect electrical monitoring data using the electrical monitoring system; mark the first set of monitoring data obtained as initial monitoring data; mark the monitoring data obtained from subsequent repeated detections as subsequent monitoring data; each set of monitoring data is considered an independent set of monitoring data; when both initial monitoring data and subsequent monitoring data exist, it is considered that continuous monitoring data exists; If the collected monitoring data is only the initial monitoring data, execute step 3 to correct the positive and negative attributes of the observed voltage value; When the collected monitoring data is continuous monitoring data, perform step 3 on the initial monitoring data to correct the positive and negative attributes of the observed voltage value, and perform step 3 or step 4 on the subsequent monitoring data to correct the positive and negative attributes of the observed voltage value; Step 3: Based on the theoretical voltage curve, the positional relationship between the transmitting electrode and the receiving electrode is used to correct the positive and negative properties of the observed voltage values ​​of the independent monitoring data; Step 4: Correct the positive and negative properties of the observed voltage values ​​using the background elimination method for the subsequent monitoring data; The step 3 includes the following sub-steps: Step 31, for a monopole-dipole device, the transmitting electrode is a monopole and the receiving electrode is a dipole; the transmitting electrode is represented by A and the coordinates are i=1,......,Ns, Ns is the total number of transmitting electrodes; the receiving electrodes are represented by M and N, and their coordinates are recorded as and l=1,......,Nr-1,m=2,......,Nr;Nr is the total number of receiving electrodes; the observed voltage value is recorded as The corrected voltage value is recorded as U i,l,m ; Position relationship between the transmitting and receiving points of the monopole-dipole device C AMN The calculation formula is as follows: C AMN ＝r AN -r AM Among them, r AM is the distance between the transmitting electrode A and the receiving electrode M, r AN is the distance between the transmitting electrode A and the receiving electrode N, The correction formula for the positive and negative properties of the voltage observed by the monopole-dipole device is as follows: Step 32, for a dipole-dipole device, the transmitting electrode is a dipole and the receiving electrode is a dipole; the transmitting electrode is represented by A and B, and the coordinates are marked as and i=1,......,Ns-1,j=2,......,Ns;Ns is the total number of transmitting electrodes; the receiving electrodes are represented by M and N, and their coordinates are recorded as and l=1,......,Nr-1,m=2,......,Nr,Nr is the total number of receiving electrodes; the observed voltage value is recorded as The corrected voltage value is recorded as U i,j,l,m ; Position relationship between the transmitting and receiving points of the dipole-dipole device C ABMN The calculation formula is as follows: Among them, r AM is the distance between the transmitting electrode A and the receiving electrode M, r AN is the distance between the transmitting electrode A and the receiving electrode N, r BM is the distance between the transmitting electrode B and the receiving electrode M, r BN is the distance between the transmitting electrode B and the receiving electrode N, The correction formula for the positive and negative properties of the voltage values ​​observed by the dipole-dipole device is as follows: Among them, i=1,......,Ns-1, j=2,......,Ns, l=1,......,Nr-1, m=2,......,Nr.

2. The method for correcting the positive and negative properties of observed voltage according to claim 1, wherein: In step 1, the electrical monitoring system includes a monitoring substation, a monitoring cable, and a monitoring electrode, wherein the monitoring electrode has transmitting and receiving functions.

3. The method for correcting the positive and negative properties of observed voltage according to claim 1, wherein: The specific operations of step 4 are as follows: The initial monitoring data is recorded as Subsequent monitoring data are recorded as k=2,......,Nt, Nt is the total number of monitoring data; the corrected monitoring data is recorded as D k , k=2,......,Nt; the simulated monitoring data of any uniform medium is recorded as D c , the voltage positive and negative attribute correction formula of subsequent monitoring data is as follows: Where, k=2,......,Nt.

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