A simulation experimental method and experimental device for monitoring air leakage in ground fissures

Abstract

This invention relates to the field of mining engineering experimental technology, and particularly to a method and apparatus for simulating ground fissure monitoring. The experimental method of this invention includes the following steps: S1: establishing an experimental model based on the coal seam structure of the target area; S2: heating the bottom of the experimental model to simulate the underground environment; S3: lowering the height of the experimental model to simulate the coal seam mining process; S4: acquiring temperature data of the cracks generated on the upper surface of the experimental model due to the height reduction, and determining whether the cracks leak air based on the temperature data. This experimental method of the present invention, by heating the bottom of the experimental model to simulate a warm underground environment, and by using the acquired temperature data of the cracks, can determine whether the cracks extend to the bottom of the experimental model and cause air leakage, thereby enabling a better study of the evolution of ground fissures.

Description

Technical Field

[0001] The invention relates to the technical field of mining engineering experiments, and in particular to a ground fissure air leakage monitoring simulation experimental method and an experimental device. Background Art

[0002] Coal will continue to dominate my country's energy structure. As coal resource development shifts to the west, high-intensity mining of shallow coal seams has caused serious surface subsidence and ground fissures, leading to soil erosion and worsening damage to the ecological environment. At the same time, there is a risk that ground fissures caused by mining shallow coal seams in western mining areas will be connected to the goaf, causing the coal in the goaf to spontaneously ignite, threatening mine production safety.

[0003] In recent years, ground fissure air leakage monitoring has been mainly carried out by on-site manual monitoring. Due to the vast scope of the goaf and the complex terrain conditions, the monitoring work has problems such as large workload, long cycle, and delayed monitoring effect, which leads to the failure to eliminate the hidden dangers of ground fissures in time. Similarity simulation test is a commonly used, scientific and reliable research method in the field of mining engineering. Similarity simulation is to make a model in the laboratory according to the similarity principle, and use the results of the study on the model to infer the phenomena and laws that may occur in the prototype. The similarity model is to scale the prototype to the laboratory in proportion according to the similarity ratio, which can truly simulate the actual situation and the results are reliable; similarity simulation is repeatable and can be tested multiple times; in addition, laboratory simulation based on mine geological data can predict the phenomena that may occur in reality.

[0004] However, at present, domestic and foreign scholars have conducted very little research on the use of similar simulations to simulate ground fissures to monitor air leakage in goafs. The domestic patent document CN108333291A discloses an experimental device and test method for simulating spontaneous combustion in goafs, which only describes the process of spontaneous combustion in goafs caused by air leakage in the mine ventilation system, and the experimental method and test bench for monitoring ground fissures causing air leakage in the atmosphere and goafs have not yet appeared. Based on the above situation, there is an urgent need for a reliable ground fissure monitoring simulation experimental method or experimental device to simulate and monitor air leakage in ground fissures during high-intensity mining in coal mines, and provide a reference basis for on-site engineering practice. Summary of the invention

[0005] The invention provides a ground fissure air leakage monitoring simulation experimental method and experimental device, which are used to solve at least one of the above problems.

[0006] One aspect of the present invention provides a ground fissure air leakage monitoring simulation experimental method, comprising the following steps:

[0007] S1: Establish an experimental model based on the coal seam structure of the target area;

[0008] S2: heating the bottom of the experimental model to simulate the underground environment;

[0009] S3: lowering the height of the experimental model to simulate the process of coal seam mining;

[0010] S4: Acquire temperature data of cracks generated on the upper surface of the experimental model caused by the height drop, and determine whether the cracks are leaking air based on the temperature data.

[0011] In one embodiment, step S4 includes the following sub-steps:

[0012] An infrared image of the upper surface of the experimental model is obtained by an infrared camera, and the temperature data of the crack is extracted from the infrared image according to a preset extraction threshold.

[0013] It is determined based on the temperature data whether the crack penetrates through the interior of the test model and causes air leakage.

[0014] In one embodiment, step S4 includes the following sub-steps:

[0015] An infrared image of the upper surface of the experimental model is obtained by an infrared camera, and an initial infrared crack extraction threshold is determined;

[0016] Acquire a visible light image of the upper surface of the experimental model by a visible light shooting device, and extract position data of the crack from the visible light image;

[0017] calibrating an initial infrared crack extraction threshold according to the obtained crack position data, and obtaining a calibrated infrared crack extraction threshold;

[0018] extracting temperature data of surface cracks from the infrared image according to a calibrated infrared crack extraction threshold;

[0019] It is determined based on the temperature data whether the crack penetrates through the interior of the test model and causes air leakage.

[0020] In one embodiment, step S1 includes the following steps:

[0021] S10: setting a heating layer in the model frame;

[0022] S11: Laying bottom layer simulation material on the heating layer to simulate coal pillars;

[0023] S12: at least one set of lifting devices is arranged inside the simulated coal pillar to simulate the coal seam;

[0024] S13: Raise the top plate of the lifting device to be flush with the top of the bottom simulation material;

[0025] S14: Laying the first simulation material layer by layer on the top plate of the jacking device and on the upper surface of the bottom simulation material to simulate the overlying rock strata until a predetermined number of layers is reached to form an experimental model.

[0026] In one embodiment, in step S14, each time a layer of the first simulation material is laid, a layer of baffle is added around the model frame.

[0027] In one embodiment, step S10 includes the following sub-steps:

[0028] Lay insulation material on the base of the model frame as a thermal insulation layer;

[0029] Lay heating elements over the insulation;

[0030] laying a second simulation material on the heating element as a heat transfer layer;

[0031] A temperature sensor is provided between the heat insulating layer and the heat transfer layer to measure the temperature of the heat transfer layer;

[0032] The heating element conducts heat to the heat transfer layer, so that the heat transfer layer can heat the bottom of the experimental model at a constant temperature.

[0033] In one embodiment, step S11 includes the following sub-steps:

[0034] Laying a hollow annular bottom layer simulation material on the heating layer;

[0035] An opening is provided on one side of the annular bottom layer simulation material to simulate a coal pillar;

[0036] Wherein, the output end and / or the input end of the lifting device extends out from the opening.

[0037] In one embodiment, the lifting device includes a jack mechanism, and the jack mechanism is connected to a hydraulic mechanism to achieve lifting and lowering operations.

[0038] In one embodiment, in step S3, the control system controls the top plate of the jacking device to descend in a specified direction at a specified speed to simulate the process of coal seam mining.

[0039] Another aspect of the present invention further provides a ground fissure air leakage monitoring simulation experimental device, comprising:

[0040] An experimental model based on the coal seam structure of the target area;

[0041] A heating system, which is used to heat the bottom of the experimental model to simulate the underground environment;

[0042] a control system for lowering the height of the experimental model to simulate a coal seam mining process; and

[0043] The information acquisition system is used to obtain temperature data of cracks generated on the experimental model caused by height drop.

[0044] In one embodiment, the information collection system includes: a mounting bracket and an infrared camera disposed on the mounting bracket; or

[0045] The information collection system comprises: a mounting bracket, and an infrared shooting device and a visible light shooting device arranged on the mounting bracket.

[0046] In one embodiment, the control system controls the lifting device in the experimental model to reduce the height of the experimental model;

[0047] Wherein, the jacking device includes a jack mechanism, the jack mechanism is connected to a hydraulic mechanism, and the control system is electrically connected to the hydraulic mechanism to control the lifting and lowering operations of the jack mechanism.

[0048] Compared with the prior art, the advantages of the present invention are: the experimental method and device of the present invention can restore the movement process of the overlying rock layer to the surface during the underground coal mining process in the mine, more realistically simulate the generation and development process of surface deformation and ground fissures caused by coal mining, and can simulate the warm underground environment and simulate the ground temperature conditions at different mining depths. By heating the bottom of the experimental model, the temperature inside the model is significantly higher than the temperature of the model surface (upper surface), so the internal temperature of the cracks appearing on the model surface will be greatly increased, and the cracks of different depths have obvious differences in temperature. According to the obtained crack temperature data, it can be judged whether the cracks are leaking, so as to better study the law of the evolution of ground cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0050] Figure 1 is a flow chart of the method of the present invention;

[0051] Figure 2 It is a schematic diagram of the overall structure of the device of the present invention;

[0052] Figure 3 It is a structural schematic diagram of the model framework of the present invention;

[0053] Figure 4 It is a structural schematic diagram of the rectangular notch of the rear baffle of the present invention;

[0054] Figure 5It is a schematic diagram of establishing an experimental model in a model framework of the present invention;

[0055] Figure 6 It is a structural schematic diagram of a simulated coal pillar of the present invention;

[0056] Figure 7 It is a schematic structural diagram of the jacking device of the present invention;

[0057] Figure 8 It is a structural schematic diagram of the heating system of the present invention;

[0058] Fig. 9 It is a structural schematic diagram of the control system of the present invention;

[0059] Fig.10 It is a structural schematic diagram of the information collection system of the present invention.

[0060] Reference numerals:

[0061] 1-base; 2-column; 3-baffle; 4-first notch; 5-second notch;

[0062] 6-simulated coal seam; 7-simulated coal pillar; 8-hollow rectangular steel; 9-jack mechanism;

[0063] 10-bottom plate; 11-hydraulic cylinder; 12-hydraulic plunger; 13-top plate;

[0064] 14-simulated overburden; 15-insulation layer; 16-heat transfer layer; 17-heating resistance wire;

[0065] 18- hydraulic pump; 19- hydraulic oil pipe; 20- hydraulic oil tank; 21- wire;

[0066] 22-heating controller; 23-central server; 24-display; 25-visible light shooting device;

[0067] 26-infrared camera; 27-data cable; 28-temperature sensor; 29-mounting bracket. DETAILED DESCRIPTION

[0068] The present invention will be further described below in conjunction with the accompanying drawings.

[0069] One aspect of the present invention provides a ground fissure air leakage monitoring simulation experimental method, such as Figure 1 As shown in , the following steps are included:

[0070] S1: Establish an experimental model based on the coal seam structure in the target area.

[0071] S2: heating the bottom of the experimental model to simulate the underground environment.

[0072] S3: lowering the height of the experimental model to simulate the process of coal seam mining.

[0073] S4: Acquire temperature data of cracks generated on the upper surface of the experimental model caused by the height drop, and determine whether the cracks are leaking air based on the temperature data.

[0074] The experimental method of the present invention can restore the movement process of the overlying rock layer to the surface during the underground coal mining process in the mine, more realistically simulate the generation and development process of surface deformation and ground fissures caused by coal mining, and can simulate the warm underground environment and simulate the ground temperature conditions under different mining depths. By heating the bottom of the experimental model, the temperature inside the model is significantly higher than the temperature of the model surface (upper surface), so the internal temperature of the cracks appearing on the model surface will be greatly increased, and the cracks of different depths have obvious differences in temperature. According to the obtained crack temperature data, it can be judged whether the cracks are leaking air, so as to better study the law of the evolution of ground cracks.

[0075] Among them, there is an obvious difference in temperature between the cracks that penetrate into the heat transfer layer at the bottom of the model and the cracks that do not penetrate into the heat transfer layer at the bottom of the model, and the cracks that penetrate into the heat transfer layer at the bottom of the experimental model are equivalent to the surface cracks penetrating into the goaf during the actual mining process. The goaf refers to the "hole" produced under the surface by artificial excavation or natural geological movement. If the surface cracks penetrate into the goaf, the coal seam is in danger of collapse.

[0076] The following is an explanation of step S4: obtaining temperature data of cracks generated on the upper surface of the experimental model caused by the height drop, and judging whether the cracks are leaking air based on the temperature data.

[0077] In one embodiment, step S4 includes the following sub-steps:

[0078] An infrared image of the upper surface of the experimental model is acquired by the infrared camera 26, and temperature data of the crack is extracted from the infrared image according to a preset extraction threshold, and it is determined based on the temperature data whether the crack penetrates through the interior of the experimental model and causes air leakage.

[0079] In this embodiment, the infrared camera 26 can directly extract all the cracks according to the crack temperature without manual counting, and the infrared camera 26 can simulate the identification of surface cracks at night.

[0080] Specifically, the infrared photographing device 26 is an infrared camera, which monitors the upper surface of the experimental model (simulated ground surface) in real time, continuously, and throughout the entire process, so as to better study the evolution law of ground fissures.

[0081] In another embodiment, step S4 includes the following sub-steps:

[0082] Acquire an infrared image of the upper surface of the experimental model through an infrared camera 26, and determine an initial infrared crack extraction threshold;

[0083] Obtaining a visible light image of the upper surface of the experimental model through a visible light shooting device 25, and extracting position data of the cracks from the visible light image;

[0084] calibrating an initial infrared crack extraction threshold according to the obtained crack position data, and obtaining a calibrated infrared crack extraction threshold;

[0085] The temperature data of the surface cracks are extracted from the infrared image according to the calibrated infrared crack extraction threshold;

[0086] It is determined based on the temperature data whether the crack penetrates through the interior of the test model and causes air leakage.

[0087] In this embodiment, the visible light shooting device 25 is used to calibrate the infrared camera to directly identify cracks according to temperature. Since cracks at different positions on the experimental model have different crack sizes and crack depths, the visible light shooting device 25 is set to shoot cracks on the surface of the experimental model under visible light conditions, and the position information of the cracks can be obtained from the visible light image, which is used to calibrate the infrared crack extraction threshold to improve the accuracy of the obtained crack temperature data.

[0088] Specifically, the visible light shooting device 25 is a high-speed camera, and the infrared shooting device 26 is an infrared camera. The infrared camera and the high-speed camera monitor the upper surface of the experimental model (simulated ground surface) in real time, continuously, and throughout the entire process, so as to better study the evolution law of ground fissures.

[0089] The following is an explanation of step S1: establishing an experimental model based on the coal seam structure of the target area.

[0090] In one embodiment, step S1 comprises the following steps:

[0091] S10: Setting a heating layer in the model frame.

[0092] S11: Laying a bottom layer simulation material on the heating layer to simulate the coal pillar 7.

[0093] S12: at least one set of lifting devices is arranged inside the simulated coal pillar 7 to simulate the coal seam 6 .

[0094] S13: Raise the top plate 13 of the lifting device to be flush with the top of the bottom layer simulation material.

[0095] S14: Laying the first simulation material layer by layer on the top plate 13 of the jacking device and on the upper surface of the bottom simulation material to simulate the overlying rock layer 14 until a predetermined number of layers is reached to form an experimental model.

[0096] Among them, the experimental model includes a heating layer, a simulated coal seam 6 and a simulated overlying rock layer 14 arranged in sequence from bottom to top. The heating layer is used to simulate the underground environment. The simulated coal seam 6 includes a simulated coal pillar 7 and multiple sets of jacking devices in the middle of the simulated coal pillar 7. The height of the top plate 13 of the jacking device can be adjusted within a certain range to simulate coal seams of different thicknesses, and by separately controlling the rising or falling actions of the corresponding jacking devices, the separate excavation of the coal seam 6 can be simulated.

[0097] Furthermore, if Figure 7 As shown in FIG. 1 , multiple groups of lifting devices are closely arranged inside the simulated coal pillar 7 so that the top plates 13 of all the lifting devices form a complete plane.

[0098] Preferably, the experimental model is established in a model frame. In step S14, each time a layer of the first simulation material is laid, a layer of baffle 3 is added around the model frame to prevent the experimental model from collapsing.

[0099] In one embodiment, step S10 includes the following sub-steps: laying a heat insulating material on the base 1 of the model frame as a heat insulating layer 15, laying a heating element on the heat insulating layer 15, laying a second simulation material on the heating element as a heat transfer layer 16, and setting a temperature sensor 28 between the heat insulating layer 15 and the heat transfer layer 16 to measure the temperature of the heat transfer layer 16.

[0100] The heating element conducts heat to the heat transfer layer 16, so that the heat transfer layer 16 can heat the bottom of the experimental model at a constant temperature.

[0101] Specifically, the heating element is a heating resistance wire 17 , and the heating resistance wire 17 is evenly laid between the heat insulation layer 15 and the heat transfer layer 16 .

[0102] Preferably, the temperature sensor 28 and the heating element are respectively connected to the heating controller 22. When the heating controller 22 detects that the heat transfer layer 16 reaches the set temperature through the temperature sensor 28, the heating controller 22 keeps the heating element heated at a constant temperature. In addition, by controlling the heating temperature of the heating element through the heating controller 22, multi-level heating can be achieved to simulate the underground environment temperature at different mining depths.

[0103] In addition, a first notch 4 is provided on the baffle plate 3 on the model frame corresponding to the position of the temperature sensor 28 , so that the data line 27 of the temperature sensor 28 can extend from the first notch 4 and be connected to the heating controller 22 .

[0104] In one embodiment, step S11 includes the following sub-steps: laying an annular bottom layer simulation material with a hollow interior on the heating layer, and setting an opening on one side of the annular bottom layer simulation material. At the same time, a second notch 5 is correspondingly opened on the baffle 3 of the bottom layer of the model frame, so that the output end and the input end of the jacking device can extend from the opening of the simulated coal pillar 7 and the second notch 5 of the baffle 3. For example, the output end and the input end of the jacking device can be a hydraulic oil pipe 19, an electric wire, etc.

[0105] Specifically, if Figure 6 As shown in FIG. , a hollow rectangular steel 8 is placed at the rear of the simulated coal pillar 7 to form an opening at the rear of the simulated coal pillar 7, as shown in FIG. Figure 4 As shown in FIG. 1 , a notch is provided on the baffle plate 3 of the bottom layer.

[0106] The following is an explanation of step S3: lowering the height of the experimental model to simulate the process of coal seam mining.

[0107] In one embodiment, the jacking device includes a jack mechanism 9, which is connected to a hydraulic mechanism, which is also connected to a control system. The control system controls the top plate 13 of the jacking device to descend in a specified direction at a specified speed to simulate the process of coal seam mining.

[0108] The jack mechanism 9 includes a bottom plate 10, a hydraulic cylinder 11 and a top plate 13 which are connected in sequence. The hydraulic cylinder 11 is provided with a retractable hydraulic plunger 12. The hydraulic mechanism is connected to the hydraulic cylinder 11 and drives the hydraulic plunger 12 to retract and retract up and down to control the rise and fall of the top plate 13. Specifically, the hydraulic mechanism is a hydraulic pump 18, which is connected to a hydraulic oil tank 20 to obtain hydraulic oil. The group control of the hydraulic mechanism is achieved by controlling the switching sequence of the hydraulic pump 18, simulating the step-by-step excavation of the coal seam 6.

[0109] It should be noted that the above-mentioned bottom simulation material, the first simulation material and the second simulation material can be the same simulation material or different simulation materials. Among them, similar simulation materials are configured according to the geological data and similarity ratio of the target area, specifically, as shown in Table 1.

[0110] Table 1 Proportions of similar simulation materials

[0111]

[0112] Another aspect of the present invention also provides a ground fissure air leakage monitoring simulation experimental device, such as Figure 2As shown in , it includes: an experimental model, a heating system, a control system and an information collection system. The heating system is used to heat the bottom of the experimental model to simulate the underground environment, the control system is used to lower the height of the experimental model to simulate the coal seam mining process, and the information collection system obtains the temperature data of the cracks on the experimental model caused by the height drop.

[0113] Among them, Figure 5 As shown in , the experimental model is established in the model framework according to the coal seam structure of the target area, such as Figure 3 As shown in , the model frame includes a base 1 and columns 2 arranged on the four corners of the base 1. Removable baffles 3 are arranged around the model frame. The baffles 3 can be connected and fixed to the columns 2 by bolts, which is convenient for installation and disassembly.

[0114] like Figure 8 As shown in the figure, the heating system is the heating layer at the bottom of the experimental model, wherein the heating layer includes a heat insulation layer 15, a heat transfer layer 16, and a heating resistor 17. The heat insulation layer 15 is a layered structure in which a heat insulation material is laid on the base 1, and the heat transfer layer 16 is a layered structure in which a similar simulation material is laid on top of the heat insulation layer 15. The heating resistor 17 is evenly laid between the heat insulation layer 15 and the heat transfer layer 16.

[0115] like Fig. 9 As shown in the figure, the control system includes a hydraulic pump 18, a pressure oil pipe, a hydraulic oil tank 20, a heating controller 22, a central server 23 and a display 24, etc. The hydraulic pump 18 is connected to the hydraulic oil tank 20 and the jack mechanism 9 respectively through a hydraulic oil pipe 19, the hydraulic oil pipe 19 is led out of the baffle 3 through a hollow rectangular steel 8 and a rectangular notch, the hydraulic pump 18 is connected to the central server 23 through a wire 21, the heating controller 22 is connected to the heating resistor wire 17, and the display 24 is connected to the central server 23.

[0116] like Fig.10 As shown in , the information collection system includes a mounting bracket 29, an infrared camera 26, a visible light camera 25, and a temperature sensor 28. The steel bracket is placed across the model frame, the high-speed camera and the infrared camera are fixed in parallel in the center of the crossbeam of the mounting bracket 29, the temperature sensor 28 is placed between the insulation layer 15 and the heat transfer layer 16, and the data cable 27 connects the visible light camera 25, the infrared camera 26, and the temperature sensor 28 to the central server 23 respectively.

[0117] The steps of conducting an experiment using the experimental device of the present invention are described in detail below, which are as follows:

[0118] a. Check the working status of each system component. After confirming that each system component is normal, install the bottom baffle 3 on the column 2;

[0119] b. Lay a layer of heat insulation material inside the baffle 3 as the heat insulation layer 15, evenly lay the heating resistance wire 17 on the heat insulation layer 15, place the temperature sensor 28 on the heat insulation layer 15 and connect the data line 27, lead the two ends of the heating resistance wire 17 and the data line 27 out of the baffle 3 through the notch of the baffle 3, and lay a layer of similar simulation material on the heating resistance wire 17 as the heat transfer layer 16;

[0120] c. Lay similar simulated materials around the upper edge of the heat transfer layer 16 as simulated coal pillars 7, and place hollow rectangular steel 8 at the rear of the simulated coal pillars 7. Place multiple sets of jack mechanisms 9 closely inside the simulated coal pillars 7, lead the hydraulic oil pipes 19 of the jack mechanisms 9 through the hollow rectangular steel 8 of the simulated coal pillars 7 and the gaps of the baffle 3, connect the hydraulic pump 18, the hydraulic oil pipe 19 and the hydraulic oil tank 20, and check whether the connection is leaking. If so, check the leaking position and reconnect. If there is no leakage, proceed to the next step;

[0121] d. Start all the hydraulic pumps 18, raise the top plate 13 of the jack mechanism 9 to a specified height, and then shut down all the hydraulic pumps 18;

[0122] e. Install the baffles 3 on the columns 2 in sequence, prepare similar simulation materials according to geological data and similarity ratios, and lay them layer by layer to form the simulated overburden stratum 14 until the simulated overburden stratum 14 is laid;

[0123] f. Let the experimental model stand for a period of time to allow the similar simulation material to fully solidify, retain the left and right side baffles 3, and remove the front and rear side baffles 3;

[0124] g. Continue to let the experimental model stand still, so that the similar simulation material can be fully air-dried, and then reinstall the removed baffle 3;

[0125] h. Install the high-speed camera and the infrared camera on the crossbeam of the mounting bracket 29, connect the high-speed camera and the infrared camera to the central server 23 using the data cable 27, connect the data cable 27 of the temperature sensor 28 to the central server 23, connect the heating resistor wire 17 to the heating controller 22, and turn on the relevant power supply;

[0126] i. When the data of the temperature sensor 28 shows that the heat transfer layer 16 reaches the set temperature, the heating controller 22 keeps the heating resistor 17 heated at a constant temperature;

[0127] j. Turn on the high-speed camera and the infrared camera to start monitoring the upper surface of the simulated overburden stratum 14;

[0128] k. Control the corresponding hydraulic pump 18 through the central server 23 to pump liquid from one side of the jack mechanism 9, so as to realize the grouped descent of the jack mechanism 9 and simulate the process of coal seam mining;

[0129] 1. After the coal seam is mined, the high-speed camera and the infrared camera are turned off after the simulated overburden stratum 14 movement is stable for a period of time, the data is exported, and the heating controller 22 is turned off to stop heating;

[0130] m. Analyze the experimental data, compare the ground fissure location information of the images taken by the high-speed camera and the infrared camera, and calibrate the shooting information of the infrared camera;

[0131] n. Extract the temperature data of ground fissures in infrared images to determine whether the cracks are leaking air;

[0132] o. Clean similar simulation materials in the model frame, remove each system component and put it back in place for the next experiment.

[0133] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A simulation experimental method for monitoring air leakage in ground fissures, characterized in that: The following steps are involved: S1: Establish an experimental model based on the coal seam structure of the target area; S2: heating the bottom of the experimental model to simulate the underground environment; S3: lowering the height of the experimental model to simulate the process of coal seam mining; S4: acquiring temperature data of cracks generated on the upper surface of the experimental model caused by the height drop, and determining whether the cracks are leaking air according to the temperature data; Step S4 includes the following sub-steps: An infrared image of the upper surface of the experimental model is obtained by an infrared camera, and an initial infrared crack extraction threshold is determined; Acquire a visible light image of the upper surface of the experimental model by a visible light shooting device, and extract position data of the crack from the visible light image; calibrating an initial infrared crack extraction threshold according to the obtained crack position data, and obtaining a calibrated infrared crack extraction threshold; extracting temperature data of surface cracks from the infrared image according to a calibrated infrared crack extraction threshold; Determining, based on the temperature data, whether the crack penetrates through the interior of the experimental model and causes air leakage; Among them, the cracks generated in the experimental model include cracks that penetrate the heat transfer layer at the bottom of the model and cracks that do not penetrate the heat transfer layer at the bottom of the model. The cracks that penetrate the heat transfer layer at the bottom of the model and the cracks that do not penetrate the heat transfer layer at the bottom of the model have obvious differences in their temperatures, and the cracks penetrating the heat transfer layer at the bottom of the experimental model are equivalent to the surface cracks penetrating into the goaf during actual mining. The goaf refers to the "holes" generated below the surface by artificial excavation or natural geological movement.

2. The experimental method according to claim 1, characterized in that Step S1 includes the following steps: S10: setting a heating layer in the model frame; S11: Laying bottom layer simulation material on the heating layer to simulate coal pillars; S12: at least one set of lifting devices is arranged inside the simulated coal pillar to simulate the coal seam; S13: Raise the top plate of the lifting device to be flush with the top of the bottom simulation material; S14: Laying the first simulation material layer by layer on the top plate of the jacking device and on the upper surface of the bottom simulation material to simulate the overlying rock strata until a predetermined number of layers is reached to form an experimental model.

3. The experimental method according to claim 2, characterized in that In step S14, each time a layer of the first simulation material is laid, a layer of baffle is added around the model frame.

4. The experimental method according to claim 2, characterized in that: Step S10 includes the following sub-steps: Lay insulation material on the base of the model frame as a thermal insulation layer; Lay heating elements over the insulation; laying a second simulation material on the heating element as a heat transfer layer; A temperature sensor is provided between the heat insulating layer and the heat transfer layer to measure the temperature of the heat transfer layer; The heating element conducts heat to the heat transfer layer, so that the heat transfer layer can heat the bottom of the experimental model at a constant temperature.

5. The experimental method according to claim 2, characterized in that: Step S11 includes the following sub-steps: Laying a hollow annular bottom layer simulation material on the heating layer; An opening is provided on one side of the annular bottom layer simulation material to simulate a coal pillar; Wherein, the output end and / or the input end of the lifting device extends out from the opening.

6. The experimental method according to claim 2, characterized in that: The jacking device comprises a jack mechanism, and the jack mechanism is connected with a hydraulic mechanism to realize lifting and lowering operations.

7. The experimental method according to claim 2, characterized in that: In step S3, the control system controls the top plate of the jacking device to descend in a specified direction at a specified speed to simulate the process of coal seam mining.

8. A ground fissure air leakage monitoring simulation experimental device, characterized in that: include: An experimental model based on the coal seam structure of the target area; A heating system, which is used to heat the bottom of the experimental model to simulate the underground environment; a control system for lowering the height of the experimental model to simulate the coal seam mining process; as well as An information acquisition system, which is used to obtain temperature data of cracks generated on the experimental model caused by height drop; obtain an infrared image of the upper surface of the experimental model through an infrared shooting device, and determine an initial infrared crack extraction threshold; obtain a visible light image of the upper surface of the experimental model through a visible light shooting device, and extract position data of the cracks from the visible light image; calibrate the initial infrared crack extraction threshold according to the obtained crack position data, and obtain the calibrated infrared crack extraction threshold; extract temperature data of surface cracks from the infrared image according to the calibrated infrared crack extraction threshold; determine whether the cracks penetrate the interior of the experimental model and cause air leakage according to the temperature data; Among them, the cracks generated in the experimental model include cracks that penetrate the heat transfer layer at the bottom of the model and cracks that do not penetrate the heat transfer layer at the bottom of the model. The cracks that penetrate the heat transfer layer at the bottom of the model and the cracks that do not penetrate the heat transfer layer at the bottom of the model have obvious differences in their temperatures, and the cracks penetrating the heat transfer layer at the bottom of the experimental model are equivalent to the surface cracks penetrating into the goaf during actual mining. The goaf refers to the "holes" generated below the surface by artificial excavation or natural geological movement.

9. The ground fissure air leakage monitoring simulation experimental device according to claim 8 is characterized in that: The information collection system comprises: a mounting bracket and an infrared shooting device arranged on the mounting bracket; or The information collection system comprises: a mounting bracket, and an infrared shooting device and a visible light shooting device arranged on the mounting bracket.

10. The ground fissure air leakage monitoring simulation experimental device according to claim 8 or 9, characterized in that: The control system controls the lifting device in the experimental model to reduce the height of the experimental model; Wherein, the jacking device includes a jack mechanism, the jack mechanism is connected to a hydraulic mechanism, and the control system is electrically connected to the hydraulic mechanism to control the lifting and lowering operations of the jack mechanism.

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