Electrode station network system for goaf fire source detection and its layout method and test method

Abstract

This invention discloses an electrode station network system for detecting fire sources in goaf areas, along with its deployment and testing methods. The system includes roadway electrode stations, goaf area electrode stations, and main roadway reference electrode stations, which are sequentially and alternately deployed below the coal and rock surface in the goaf area of ​​a coal mine. Each electrode station comprises a detection conductor, flexible graphite cloth, a conductor network, a graphite mortar base, and a grounding metal electrode. The resistivity ρ of the coal and rock surface within the goaf area is measured using a rock resistivity meter, and the theoretical grounding resistance R of a single electrode station is calculated. g And thus the theoretical grounding resistance R of the electrode station g Based on this, the dimensions of the pre-deployed electrode stations are determined, and the spacing between the electrode stations in the roadway, the goaf, and the reference electrode station in the main roadway are also determined. This invention features high temperature resistance, corrosion resistance, good stability, and high detection accuracy, making it extremely suitable for detecting concealed fire sources in coal mine goafs in extreme underground environments.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of coal mine fire source detection electrodes, and particularly relates to an electrode station network system for goaf fire source detection and a laying method and a testing method thereof. BACKGROUND

[0002] The conductive electrical method is a mature geophysical prospecting method for observing the ground medium current field through grounding electrodes. Common means of this method include resistivity method, natural electric field method, charging method and induced polarization method, and the method is widely applied to regional geology, hydrogeology, engineering geology, environmental geology and coalfield geology and other fields.

[0003] The grounding electrode, as a sensor probe of the conductive electrical method, can also be used as a sensor for regional fire source detection. The grounding electrode mainly has three types of metal electrode, liquid non-polarizable electrode and solid non-polarizable electrode. The metal electrode is mainly made of copper and iron materials, and has an iron drill shape and electronic conduction. The liquid non-polarizable electrode is filled with electrolyte solutions such as CuSO4 and NaCl in an insulating electrode tank, and the bottom is close to the measured object by using a cork or ceramic diaphragm, and the conduction is ionic conduction. The solid non-polarizable electrode is mainly mixed and solidified by PbCl2, AgCl and other metal salt-containing salts and kaolin, gypsum and other materials, and the conduction is ionic conduction. The above electrodes cannot be practically applied to coalfield fire source detection. Specifically, the metal electrode has poor corrosion resistance in the extreme environment of the coal mine underground, the liquid non-polarizable electrode and the solid non-polarizable electrode are difficult to withstand the impact of the falling rocks in the coal mine underground, and cannot withstand high temperature above 200 DEG C, and need daily maintenance, so they cannot meet the harsh environmental requirements of the goaf in the coal mine underground.

[0004] In addition, in the prior art, the conventional detection network is arranged on the ground, and the laying method is as follows: the electrode points are not in direct contact with the goaf in the coal mine underground, the electrode points are generally arranged according to the profile and the regular survey network, and the point distance and the line distance are set according to the exploration accuracy requirement. Since the electrode points on the ground have a certain distance from the goaf fire source underground, the detection accuracy is not high. SUMMARY

[0005] The application is aimed at the above problems, and provides an electrode station network system for coal mine goaf fire source detection, which has high temperature resistance, corrosion resistance, good stability and high detection accuracy, and a laying method and a testing method thereof.

[0006] To achieve the above object, the application adopts the following technical scheme.

[0007] In one aspect, the application provides a goaf fire source detection electrode station network system, comprising a roadway electrode station, a goaf electrode station and a main roadway reference electrode station, the roadway electrode station, the goaf electrode station and the main roadway reference electrode station are arranged in the coal rock ground of the goaf in the underground coal mine in sequence, and the roadway electrode station, the goaf electrode station and the main roadway reference electrode station are electrode stations of the same structure; each electrode station comprises a detection lead wire, a flexible graphite cloth, a lead wire net, a graphite cement paste base and a grounding metal electrode, the flexible graphite cloth is arranged in layers, the lead wire net is arranged between the layers of the flexible graphite cloth, the graphite cement paste base is arranged below the lower flexible graphite cloth, the grounding metal electrode is vertically connected to the four corners of the layered flexible graphite cloth, the lead wire net and the graphite cement paste base, and the detection lead wire is connected to the combination of the flexible graphite cloth, the lead wire net, the graphite cement paste base and the grounding metal electrode.

[0008] As a preferred scheme of the application, the detection lead wire is composed of mica paper wrapped nickel wire and high-temperature-resistant insulating glass fiber, and the tolerance temperature of the detection lead wire is 1000°C.

[0009] As another preferred scheme of the application, the flexible graphite cloth is made of graphite, cotton yarn, glass fiber and carbonized fiber through a synthesis process, and the solid resistivity of the flexible graphite cloth is 0.06Ω·m. m .

[0010] As another preferred scheme of the application, the lead wire net is woven by nickel alloy wire, stainless steel wire and copper wire.

[0011] As another preferred scheme of the application, the graphite cement paste base is made of superfine flake graphite powder, conductive clay, organic solvent and resin adhesive, the graphite cement paste base is in a semi-solid state, and the tolerance temperature of the graphite cement paste base is 1000°C.

[0012] As another preferred scheme of the application, the grounding metal electrode is made of nickel alloy and stainless steel material.

[0013] In another aspect, the application provides a goaf fire source detection electrode station network system layout method, comprising the following steps:

[0014] (1) Before layout, first measure the coal rock resistivity of the ground in the goaf p , calculate the theoretical grounding resistance of a single electrode station R g , and determine the size of the pre-laid electrode station according to the theoretical grounding resistance of the electrode station R g

[0015] ​(2) Then, respectively determine the arrangement interval of the roadway electrode station, the arrangement interval of the goaf electrode station, and the arrangement interval of the main roadway reference electrode station;

[0016] (3) Then, in the goaf of the coal mine, select the layout position, and intervally arrange the roadway electrode station and the main roadway reference electrode station below the coal rock ground near the coal pillar side, and intervally arrange the goaf electrode station below the coal rock ground at the intermediate position of the main roadway and the auxiliary roadway;

[0017] (4) After the layout position is selected, according to the size and interval determined in step (1), dig a pit on the coal rock ground where the electrode station is arranged, and perform a leveling treatment on the coal rock surface in the pit to ensure that the pit bottom is a fresh original coal rock surface;

[0018] (5) Pour and coat graphite cement paste in the pit to form a graphite cement paste base, and the thickness of the graphite cement paste base depends on the leveling degree of the coal rock surface in the pit to ensure that the upper surface of the static graphite cement paste base completely covers the fresh original coal rock surface of the pit bottom;

[0019] (6) Lay a layer of flexible graphite cloth above the graphite cement paste base in the pit, then lay a wire net above the layer of flexible graphite cloth, and then lay a layer of flexible graphite cloth above the wire net;

[0020] (7) vertically nail the grounding metal electrode from the upper layer of flexible graphite cloth at the four corner edge positions through the wire net, the lower layer of flexible graphite cloth, the graphite cement paste base to the underground, and then connect the detection wire to the combination of the flexible graphite cloth, the wire net, the graphite cement paste base and the grounding metal electrode and lead out on the coal rock ground outside the pit;

[0021] (8) Finally, connect the detection wire of each electrode station to the grounding resistance testing instrument in sequence to test the laying effect of each electrode station, and ensure that the actual test parameter error of each electrode station does not exceed 20% of the design error, if the requirement is met, fill the pit with broken stones and tamp it, if the requirement is not met, increase the area of the flexible graphite cloth and the number of grounding metal electrodes or pour and coat more graphite cement paste around the flexible graphite cloth until the requirement is met.

[0022] Further, the coal rock resistivity p The theoretical grounding resistance of a single electrode station is measured by a rock resistivity measuring instrument R g The calculation formula is: , wherein R 1 the grounding resistance (Ω) of the flexible graphite cloth, R 2 the grounding resistance (Ω) of the grounding metal electrode, R mThe mutual grounding resistance (Ω) between the flexible graphite cloth grounding and the grounding metal electrode.

[0023] The grounding resistance of the flexible graphite cloth R 1 The calculation formula is: In the formula p The resistivity of coal and rock (Ω· m ), r The radius of the circle representing the equivalent area of ​​the flexible graphite cloth. h The thickness of the upper flexible graphite cloth to the coal and rock surface;

[0024] The grounding resistance of the grounded metal electrode R 2 The calculation formula is: In the formula p The resistivity of coal and rock (Ω· m ), L R The length of each grounding metal electrode ( m ), b The radius of the grounded metal electrode ( m ), n R In an area of s The number of grounding metal electrodes arranged on it;

[0025] The mutual grounding resistance between the flexible graphite cloth grounding and the grounding metal electrode R m The calculation formula is: ,in In the formula: p The resistivity of coal and rock (Ω· m ), L R The length of each grounding metal electrode ( m ), r 1 To reach the long semi-axis of the equipotential surface at the end of the grounded metal electrode, r The radius of the circle representing the equivalent area of ​​the flexible graphite cloth.

[0026] Furthermore, the arrangement spacing between the roadway electrode stations, the arrangement spacing between the goaf electrode stations, and the arrangement spacing between the main roadway reference electrode stations are all set according to the coal seam spontaneous combustion level, the fracture structure development, and the distribution characteristics of the mining space around the fire source detection working face.

[0027] Furthermore, in step (6), graphite mortar is poured between the two layers of flexible graphite cloth and the wire mesh between the layers to remove the interlayer pores.

[0028] Further, in the step (5), the fresh raw coal surface above the pit bottom is more than 1cm above the graphite glue base upper surface.

[0029] Further, in the step (7), the grounding metal electrode is nailed into the ground to a depth of 0.2m.

[0030] Further, in the step (8), the thickness of the gravel filled in the pit is more than 0.3m.

[0031] In another aspect, the application provides a test method for the electrode station network system of the goaf fire source detection, which uses the grounding resistance testing instrument to test the laying effect of each electrode station.

[0032] The two probes connected to the P end and the C end of the grounding resistance testing instrument are respectively inserted into the ground along the radiation direction of a tested electrode station in the electrode station network system, and the insertion depth is 0.4m; the E end of the grounding resistance testing instrument is connected to the detection wire of the tested electrode station; after the grounding resistance testing instrument is placed horizontally, whether the pointer of the galvanometer points to the center line is checked; the magnification scale is placed at the maximum magnification, and the generator handle is slowly rotated, and the measurement scale is rotated at the same time, so that the pointer of the galvanometer points to the center line; when the pointer of the galvanometer approaches to be balanced, the rotation speed of the generator handle is increased to more than 120r / min, and the measurement scale is adjusted at the same time, so that the pointer of the galvanometer points to the center line; if the reading of the measurement scale is too small, it is not easy to accurately read the reading, which indicates that the magnification scale magnification is too large; at this time, the magnification scale is placed at a smaller magnification, and the measurement scale is adjusted again, so that the pointer of the galvanometer points to the center line and the accurate reading is read out.

[0033] The measurement result of the actual measurement grounding resistance R of the electrode station is calculated, that is, the actual measurement grounding resistance R=magnification scale reading x measurement scale reading; when the actual measurement grounding resistance R of the electrode station is greater than the theoretical grounding resistance R R g When the error is more than 100%, it is considered that the laying of the tested electrode station does not meet the requirements, and must be treated or re-laid.

[0034] The beneficial effects of the application are as follows:

[0035] The electrode station laid by the application has the effects of high temperature resistance, corrosion resistance, good stability and high detection precision, and is extremely suitable for the detection of hidden fire sources in the goaf of a coal mine in an extreme environment. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1It is a layout embodiment schematic view of the electrode station net system of the application.

[0037] Figure 2 It is a structure schematic view of the electrode station of the application.

[0038] Figure 3 It is a structure schematic view of the grounding resistance testing instrument of the application.

[0039] Marked in the figure: 1 is a roadway electrode station; 2 is a goaf electrode station; 3 is a detection lead wire; 4 is a main roadway reference electrode station; 5 is a grounding metal electrode; 6 is a flexible graphite cloth; 7 is a graphite paste base; 8 is a lead wire net; 9 is a grounding resistance testing instrument; 10 is a measurement scale disc; 11 is a generator handle; 12 is a galvanometer; 13 is a magnification scale; 14 is a probe. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and beneficial effects solved by the application more clearly understood, the application is further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0041] Reference Figure 1 and Figure 2 As shown in the figure, the electrode station net system for goaf fire source detection provided by the embodiment of the application comprises a roadway electrode station 1, a goaf electrode station 2 and a main roadway reference electrode station 4, the roadway electrode station 1, the goaf electrode station 2 and the main roadway reference electrode station 4 are arranged in the coal rock ground below the goaf in the underground coal mine in sequence with intervals, and the roadway electrode station 1, the goaf electrode station 2 and the main roadway reference electrode station 4 are all electrode stations with the same structure; each electrode station comprises a detection lead wire 3, a flexible graphite cloth 6, a lead wire net 8, a graphite paste base 7 and a grounding metal electrode 5, the flexible graphite cloth 6 is arranged in layers from top to bottom, the lead wire net 8 is arranged between the layers of the flexible graphite cloth 6, the graphite paste base 7 is arranged below the lower flexible graphite cloth 6 below the lead wire net 8, the flexible graphite cloth 6, the lead wire net 8 and the graphite paste base 7 arranged in layers are vertically connected to the grounding metal electrode 5 at the four corners, and the detection lead wire 3 is connected to the combination of the flexible graphite cloth 6, the lead wire net 8, the graphite paste base 7 and the grounding metal electrode 5.

[0042] The detection lead wire 3 is composed of mica paper wrapped nickel wire and high-temperature-resistant insulating glass fiber, and the tolerance temperature of the detection lead wire 3 is 1000℃.

[0043] The flexible graphite cloth 6 is made of graphite, cotton yarn, glass fiber and carbonized fiber through a synthesis process, and the solid resistivity of the flexible graphite cloth 6 is 0.06Ω· m .

[0044] The wire net 8 is woven by nickel alloy wire, stainless steel wire and copper wire.

[0045] The graphite paste base 7 is made of superfine flake graphite powder, conductive clay, organic solvent and resin adhesive, and is in a semi-solid state.

[0046] The ground metal electrode 5 is made of nickel alloy and stainless steel material.

[0047] The electrode station formed by the detection wire 3, the flexible graphite cloth 6, the wire net 8, the graphite paste base 7 and the ground metal electrode 5 can ensure that the electrode station net system has the effects of high temperature resistance, corrosion resistance and long-term stability.

[0048] The electrode station net system for goaf fire source detection provided by the embodiment of the application comprises the following steps:

[0049] (1) Considering the detection accuracy and the best coupling ground effect, before the layout, the coal and rock resistivity of the ground in the goaf is measured first p , the theoretical ground resistance of a single electrode station is calculated R g , and the size of the pre-laid electrode station is determined according to the theoretical ground resistance of the electrode station R g , the layout spacing of the roadway electrode station 1, the layout spacing of the goaf electrode station 2 and the layout spacing of the main roadway reference electrode station 4 are determined respectively.

[0050] (2) Then, in the goaf of the coal mine, the layout position is selected, the roadway electrode station 1 and the main roadway reference electrode station 4 are laid at intervals below the coal and rock ground near the coal pillar, and the goaf electrode station 2 is laid at intervals below the coal and rock ground at the intermediate position of the main roadway and the auxiliary roadway; the geological stress stable area far away from the structure and the lithology interface is selected as much as possible, and the production operation of the underground coal mine is not affected and is not easy to be damaged.

[0051] (3) After the layout position is selected, the pit is opened on the coal and rock ground of the electrode station according to the size and spacing determined in step (1), and the coal and rock surface in the pit is flattened to ensure that the pit bottom is a fresh coal and rock surface.

[0052] (4) The graphite paste is poured in the pit to form the graphite paste base 7, and the thickness of the graphite paste base 7 depends on the flatness of the coal and rock surface in the pit, so that the upper surface of the static graphite paste base 7 is completely above the fresh coal and rock surface of the pit bottom; specifically, the upper surface of the graphite paste base 7 is above the fresh coal and rock surface of the pit bottom by more than 1 cm.

[0053] (5) A layer of flexible graphite cloth 6 is laid on top of the graphite mortar base 7 in the pit, and then a wire mesh 8 is laid on top of this layer of flexible graphite cloth 6, and then another layer of flexible graphite cloth 6 is laid on top of the wire mesh 8. In order to ensure the contact coupling between the wire mesh 8 and the flexible graphite cloth 6, and to avoid the wire mesh 8 from being exposed to natural oxidation for a long time, graphite mortar is poured between the two layers of flexible graphite cloth 6 and the wire mesh 8 between them to drain the interlayer pores.

[0054] (6) The grounding metal electrode 5 is driven vertically into the ground from the four corners of the upper flexible graphite cloth 6, through the wire mesh 8, the lower flexible graphite cloth 6, and the graphite mortar base 7. The depth of the grounding metal electrode 5 is 0.2m. Then the detection wire 3 is connected to the combination of the flexible graphite cloth 6, the wire mesh 8, the graphite mortar base 7 and the grounding metal electrode 5 and led out to the coal and rock ground outside the pit.

[0055] (7) Finally, connect the test wires 3 of each electrode station to the grounding resistance test instrument 9 in sequence, and test the laying effect of each electrode station accordingly. Ensure that the actual test parameter error of each electrode station does not exceed 20% of the design error. If the requirements are met, fill the pit with crushed stone and compact it. The thickness of the crushed stone should be more than 0.3m. If the requirements are not met, increase the area of ​​the flexible graphite cloth 6 and the number of grounding metal electrodes 5, or pour more graphite slurry around the flexible graphite cloth 6 until the requirements are met.

[0056] The resistivity of the coal and rock p The theoretical grounding resistance of a single electrode station was measured using a rock resistivity meter. R g The calculation formula is: In the formula R 1 The grounding resistance (Ω) of flexible graphite cloth 6. R 2 The grounding resistance (Ω) of the grounded metal electrode 5. R m The mutual grounding resistance (Ω) between the flexible graphite cloth 6 grounding and the grounding metal electrode 5.

[0057] The grounding resistance of the flexible graphite cloth 6 R 1 The calculation formula is: In the formula p The resistivity of coal and rock (Ω· m ), r The radius of the circle representing the equivalent area of ​​the flexible graphite cloth 6. h The thickness of the upper flexible graphite cloth is 6 to that of the coal and rock surface.

[0058] The grounding resistance of the grounded metal electrode R2 The calculation formula is: In the formula p The resistivity of coal and rock (Ω· m ), L R The length of each grounding metal electrode 5 ( m ), b The radius of the grounded metal electrode 5 ( m ), n R In an area of s The number of grounding metal electrodes 5 arranged on it;

[0059] The mutual grounding resistance between the flexible graphite cloth 6 and the grounding metal electrode 5 R m The calculation formula is: ,in In the formula: p The resistivity of coal and rock (Ω· m ), L R The length of each grounding metal electrode 5 ( m ), r 1 To reach the long semi-axis of the equipotential surface at the end of the grounded metal electrode 5, r The radius of the circle representing the equivalent area of ​​the flexible graphite cloth 6.

[0060] Based on the above-mentioned electrode station theoretical grounding resistance R g The calculation method shows that the theoretical grounding resistance of the electrode station R g The area of ​​the flexible graphite cloth 6 and the grounding metal electrode 5 is inversely proportional to the area of ​​the grounding metal electrode 5. Since the coal and rock in the well environment are relatively hard, the grounding metal electrode 5 is laid at a relatively shallow depth. Therefore, the area of ​​the flexible graphite cloth 6 plays a decisive role in the grounding effect. The larger the grounding area, the lower the grounding resistance.

[0061] The theoretical grounding resistance of the electrode station R g With the resistivity of coal and rock p Let the ratio be a, when the theoretical grounding resistance of the electrode station is... R g With the resistivity of coal and rock p When the ratio 'a' is less than 1 / 2, the grounding area is too small and the resistance reduction effect is poor; when the theoretical grounding resistance of the electrode station... R g With the resistivity of coal and rock pWhen the ratio a is greater than 1 / 4, the reduction of the grounding resistance is not obvious, and the utilization rate of the electrode material is greatly reduced. Therefore, the area of the flexible graphite cloth 6 is designed to meet the requirement of 1 / 4 < a < 1 / 2, and the relationship between the electrode station laying cost and the resistance reduction effect is comprehensively considered.

[0062] The arrangement spacing between the roadway electrode stations 1, the arrangement spacing between the goaf electrode stations 2, and the arrangement spacing between the main roadway reference electrode stations 4 are set according to the coal seam spontaneous combustion grade, the fracture structure development condition, and the distribution characteristics of the fire source detection working face surrounding mining space.

[0063] Specifically, the basic spacing of the electrode stations is set according to the coal seam spontaneous combustion grade: when the coal seam spontaneous combustion grade is extremely easy to combust, the basic spacing of the electrode stations is not less than 20 m; when the coal seam spontaneous combustion grade is easy to combust, the basic spacing of the electrode stations is not less than 30 m; and when the coal seam spontaneous combustion grade is relatively easy to combust, the basic spacing of the electrode stations is not less than 40 m.

[0064] Specifically, the basic spacing of the electrode stations is set according to the fracture structure development condition: in the fracture structure development section, the basic spacing of the electrode stations is not less than 10 m; and in the fracture structure relatively developed section, the basic spacing of the electrode stations is not less than 20 m.

[0065] Specifically, the basic spacing of the electrode stations is set according to the distribution characteristics of the fire source detection working face surrounding mining space: in the goaf and roadway staggered complex section, the basic spacing of the electrode stations is not less than 10 m; and in the goaf and roadway distribution relatively complex section, the basic spacing of the electrode stations is not less than 20 m.

[0066] In combination with the above-mentioned electrode station arrangement spacing setting method, the electrode station arrangement spacing setting method is applied to the electrode station arrangement spacing setting of the coal seam spontaneous combustion grade, the fracture structure development condition, and the distribution characteristics of the fire source detection working face surrounding mining space. Figure 3As shown in the embodiment of the present invention, a testing method for an electrode station network system for detecting fire sources in a goaf area is provided. The grounding resistance testing instrument 9 is used to test the laying effect of each electrode station. The grounding resistance testing instrument 9 is equipped with a measuring scale 10, a generator handle 11, a galvanometer 12, a magnification scale 13, probes 14, and three connection terminals: E terminal, P terminal, and C terminal. Probes 14 are connected to both P and C terminals. The two probes 14 connected to the P and C terminals of the grounding resistance testing instrument 9 are inserted into the ground along the radiation direction of one of the tested electrode stations in the electrode station network system, to a depth of 0.4m. The E terminal of the grounding resistance testing instrument 9 is connected to the detection wire 3 of the tested electrode station. After placing the grounding resistance testing instrument 9 horizontally, it is checked whether the pointer of the galvanometer 12 points to the center line. The magnification scale is then... 13. Set the multiplier to the maximum and slowly rotate the generator handle 11 while simultaneously rotating the measuring scale 10 until the galvanometer 12 pointer points to the center line. When the galvanometer 12 pointer is close to equilibrium, accelerate the rotation of the generator handle 11 to a speed of 120 r / min or higher, while simultaneously adjusting the measuring scale 10 to make the galvanometer 12 pointer point to the center line. If the reading on the measuring scale 10 is too small and difficult to read accurately, it indicates that the multiplier 13 is too large. In this case, set the multiplier 13 to a smaller multiplier, readjust the measuring scale 10, and make the galvanometer 12 pointer point to the center line and read an accurate reading. Calculate the actual measured grounding resistance R of the electrode station, i.e., actual measured grounding resistance R = multiplier 13 reading × measuring scale 10 reading. When the actual measured grounding resistance R of the electrode station is compared with the theoretical grounding resistance... R g If the error exceeds 100%, the electrode station under test is considered to be unsatisfactory and must be treated or re-laid.

[0067] In addition, to ensure the accuracy of fire source detection in goaf areas, it is essential to ensure the grounding resistance of all measured electrode stations within the electrode station network system. R C To meet the requirement of relative uniformity, that is, the standard deviation σ of the grounding resistance of all electrode stations is not greater than the average measured grounding resistance of all electrode stations. 10% of the total grounding resistance is used as the criterion for determining the qualification of the electrode station network combination; the formula for calculating the standard deviation σ of the grounding resistance of all electrode stations is as follows:

[0068] ;

[0069] in, n This represents the number of electrode stations in the electrode station network. R Ci Let be the measured grounding resistance of the i-th electrode station; σ is the average measured grounding resistance of all electrode stations; σ is the standard deviation of the grounding resistance of all electrode stations.

[0070] It can be understood that the above specific description of the present application is only for illustrating the present application and is not limited to the technical solutions described in the embodiments of the present application. Those skilled in the art should understand that the present application can still be modified or replaced equivalently to achieve the same technical effects. As long as the use needs are met, it is within the protection scope of the present application.

Claims

1. A method for deploying an electrode station network system for detecting fire sources in goaf areas, characterized in that: Includes the following steps: (1). Before deployment, the resistivity of coal and rock on the ground in the goaf area should be measured first. ρ Calculate the theoretical grounding resistance of a single electrode station. R g And thus the theoretical grounding resistance of the electrode station R g This serves as the basis for determining the dimensions of the pre-deployed electrode stations; (2). Then determine the arrangement spacing of the electrode stations in the roadway, the arrangement spacing of the electrode stations in the goaf, and the arrangement spacing of the reference electrode stations in the main roadway respectively; (3). Then, in the goaf area of ​​the coal mine, select the deployment location and deploy the roadway electrode station and the main roadway reference electrode station at intervals below the coal rock surface on the side close to the coal pillar, and deploy the goaf area electrode station at intervals below the coal rock surface in the middle of the main roadway and the auxiliary roadway. (4). After the location is selected, pits are dug on the coal and rock surface where the electrode station is to be deployed, according to the size and spacing determined in step (1), and the coal and rock surface in the pit is leveled to ensure that the bottom of the pit is a fresh raw coal and rock surface. (5) Pour graphite mortar into the pit to form a graphite mortar base. The thickness of the graphite mortar base depends on the flatness of the coal and rock surface in the pit. Ensure that the surface of the static graphite mortar base completely covers the fresh raw coal and rock surface at the bottom of the pit. (6) Lay a layer of flexible graphite cloth on top of the graphite mortar base in the pit, then lay a wire mesh on top of this layer of flexible graphite cloth, and then lay a layer of flexible graphite cloth on top of the wire mesh. (7) The grounding metal electrode is driven vertically into the ground from the four corners of the upper flexible graphite cloth, through the wire mesh, the lower flexible graphite cloth, and the graphite mortar base; then the detection wire is connected to the combination of the flexible graphite cloth, the wire mesh, the graphite mortar base and the grounding metal electrode and led out to the coal and rock surface outside the pit. (8). Finally, connect the test wires of each electrode station to the grounding resistance tester in sequence, and test the laying effect of each electrode station accordingly. Ensure that the actual test parameter error of each electrode station does not exceed 20% of the design error. If the requirements are met, fill the pit with gravel and compact it. If the requirements are not met, the area of ​​the flexible graphite cloth and the number of grounding metal electrodes can be increased, or more graphite slurry can be poured around the flexible graphite cloth until the requirements are met. The resistivity of the coal and rock ρ The theoretical grounding resistance of a single electrode station was measured using a rock resistivity meter. R g The calculation formula is: In the formula R 1 The grounding resistance of the flexible graphite cloth. R 2 The grounding resistance of the grounded metal electrode. R m The mutual grounding resistance between the flexible graphite cloth grounding and the grounding metal electrode; The grounding resistance of the flexible graphite cloth R 1 The calculation formula is: In the formula ρ For the resistivity of coal and rock, r The radius of the circle representing the equivalent area of ​​the flexible graphite cloth. h The thickness of the upper flexible graphite cloth to the coal and rock surface; The grounding resistance of the grounded metal electrode R 2 The calculation formula is: In the formula ρ For the resistivity of coal and rock, L R The length of each grounding metal electrode, b Let be the radius of the grounded metal electrode. n R In an area of s The number of grounding metal electrodes arranged on it; The mutual grounding resistance between the flexible graphite cloth grounding and the grounding metal electrode R m The calculation formula is: ,in In the formula: ρ For the resistivity of coal and rock, L R The length of each grounding metal electrode, r 1 To reach the long semi-axis of the equipotential surface at the end of the grounded metal electrode, r The radius of the circle representing the equivalent area of ​​the flexible graphite cloth.

2. The method for deploying an electrode station network system for detecting fire sources in goaf areas as described in claim 1, characterized in that: The spacing between the electrode stations in the roadway, the spacing between the electrode stations in the goaf, and the spacing between the reference electrode stations in the main roadway are all set according to the spontaneous combustion level of the coal seam, the development of the fracture structure, and the distribution characteristics of the mining space around the fire source detection working face.

3. An electrode station network system for detecting fire sources in goaf areas, characterized in that: The method of deploying the electrode station network system for detecting fire sources in goaf areas as described in claim 1 or 2 includes roadway electrode stations, goaf area electrode stations, and main roadway reference electrode stations. The roadway electrode stations, goaf area electrode stations, and main roadway reference electrode stations are deployed sequentially and at intervals below the coal and rock surface in the goaf area of ​​the coal mine. The roadway electrode stations, goaf area electrode stations, and main roadway reference electrode stations are all electrode stations with the same structure. Each electrode station includes a detection wire, flexible graphite cloth, a wire mesh, a graphite slurry base, and a grounding metal electrode. The flexible graphite cloth is arranged in upper and lower layers. The wire mesh is arranged between the layers of the flexible graphite cloth. The graphite slurry base is arranged below the flexible graphite cloth below the wire mesh. The grounding metal electrode is vertically connected to the four corners of the layered flexible graphite cloth, wire mesh, and graphite slurry base. The detection wire is connected to the assembly composed of the flexible graphite cloth, wire mesh, graphite slurry base, and grounding metal electrode.

4. The electrode station network system for detecting fire sources in goaf areas as described in claim 3, characterized in that: The detection lead is composed of mica paper wrapped with nickel wire and high-temperature resistant insulating glass fiber, and the detection lead can withstand a temperature of 1000℃.

5. The electrode station network system for detecting fire sources in goaf areas as described in claim 3, characterized in that: The flexible graphite cloth is made from graphite, cotton yarn, glass fiber, and carbon fiber through a synthesis process. The solid-state resistivity of the flexible graphite cloth is 0.06 Ω·m. m .

6. The electrode station network system for detecting fire sources in goaf areas as described in claim 3, characterized in that: The conductor mesh is woven from nickel alloy wire, stainless steel wire, and copper wire.

7. The electrode station network system for detecting fire sources in goaf areas as described in claim 3, characterized in that: The graphite mortar base is made of ultrafine flake graphite powder, conductive clay, organic solvent and resin binder. The graphite mortar base is in a semi-solid state and has a temperature resistance of 1000℃.

8. The electrode station network system for detecting fire sources in goaf areas as described in claim 3, characterized in that: The grounding metal electrode is made of nickel alloy or stainless steel.

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