Apparatus for simulating a closed mine pollution source and reactive erosion and method of use thereof

Abstract

This invention provides a device and its method for simulating pollution sources and reactive erosion in closed mines, belonging to the technical field of mine production testing devices. The technical solution includes a box body with an opening at the top. Two opposite sidewalls of the box body are closed surfaces, and the other two opposite sidewalls are open surfaces. Multiple horizontal bars are equidistantly arranged on the open surfaces, and acrylic plates are placed between adjacent horizontal bars. Multiple monitoring holes are set on the acrylic plates, and the multiple acrylic plates seal the corresponding open surfaces. Water inlets and outlets are respectively located at the bottom and top of the box body. Inside the box body, similar materials are used to sequentially lay a bottom rock layer, a first coal seam, a first aquitard, a second coal seam, a second aquitard, an aquifer, and a Quaternary rock layer from bottom to top. Monitoring mechanisms are installed within the first and second aquitards. The device also includes a sampling mechanism, a sealing mechanism, and a spring needle mechanism.

Description

Technical Field

[0001] This invention relates to the field of mine production testing equipment technology, and in particular to an apparatus and its method of use for simulating pollution sources and reactive erosion in closed mines. Background Technology

[0002] The environmental problems following coal mine closures are receiving increasing attention, particularly the risks posed by water pollution and chemical reactions. These issues not only affect the quality of groundwater and surface water but also involve the treatment of mine water discharge and the restoration of surrounding ecosystems. When residual coal and sulfide minerals in closed mines come into contact with oxygen and water, they undergo oxidation reactions to produce sulfuric acid, leading to acidification of the mine water and the formation of acidic mine drainage. This drainage not only corrodes mine facilities but also pollutes surrounding water bodies and damages ecosystems. Furthermore, mine water often contains high concentrations of heavy metals such as iron, manganese, lead, zinc, and copper. Once these heavy metals enter water bodies, they pose a serious threat to aquatic life and human health. The migration and accumulation of heavy metals also affect soil quality and agricultural production. Chemical agents and organic solvents used in coal mining and washing processes may also remain in the mines. After closure, these organic pollutants enter water bodies through mine water, further deteriorating water quality. After the mine is closed, sulfide minerals in the mine will undergo redox reactions with oxygen and water to produce sulfuric acid and metal ions, leading to water acidification and the release of a large amount of heat, affecting the groundwater temperature. At the same time, metal ions in the mine water will undergo precipitation reactions when they encounter alkaline substances, forming metal precipitates. These precipitates can block mine passages, affect water flow, and may even cause mine water overflows.

[0003] Currently, our understanding of water pollution and chemical reaction processes after coal mine closure is insufficient, lacking systematic research and comprehensive remediation plans. This lack of understanding of these complex geochemical and environmental processes makes it difficult to formulate effective pollution prevention and ecological restoration measures, thus failing to completely resolve the environmental problems following coal mine closure. Therefore, there is an urgent need to design a device that can recreate the water pollution and reactive erosion caused by coal seam mining, conduct systematic research and scientific remediation combining knowledge from multiple disciplines such as geology, hydrology, chemistry, and biology, and assess the environmental risks after coal mine closure. Through scientific research and effective remediation, the negative environmental impacts of coal mine closure can be reduced, achieving sustainable development of the mining area. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems in the prior art and provide a device and method for simulating the pollution sources and reactive erosion of closed mines, which can realize the reproduction of the changes in the chemical properties of the polluted water source and the reactive erosion of the mine water under the condition that the mine has been excavated and closed.

[0005] To achieve the above-mentioned objectives, the present invention employs the following technical solution: a device for simulating pollution sources and reactive erosion in closed mines, comprising a box body with an opening at the top. Two opposite sidewalls of the box body are closed surfaces, and the other two opposite sidewalls are open surfaces. Multiple horizontal bars are equidistantly arranged on the open surfaces, and acrylic plates are arranged between adjacent horizontal bars. Multiple monitoring holes are provided on the acrylic plates, and the multiple acrylic plates close the corresponding open surfaces. A water inlet and a water outlet are respectively provided at the bottom and top of the box body. Inside the box body, a bottom rock layer, a first coal seam, a first water-resistant layer, a second coal seam, a second water-resistant layer, an aquifer, and a Quaternary rock layer are laid sequentially from bottom to top using similar materials. Monitoring mechanisms are provided within the first and second water-resistant layers.

[0006] A detachable sampling mechanism is provided on the monitoring hole corresponding to the aquifer and the base rock layer. The sampling mechanism is used to sample the water in the aquifer and the base rock layer.

[0007] A detachable sealing mechanism is provided on the monitoring hole corresponding to the first and second waterproof layers, and the sealing mechanism is provided with a wiring port;

[0008] A detachable spring needle mechanism is provided on the monitoring hole corresponding to the first and second coal seams. The spring needle mechanism is used to stimulate the mining of the first and second coal seams to simulate the coal seam goaf.

[0009] Furthermore, the monitoring hole is provided with internal threads; the similar materials used to simulate the bottom rock layer, the first aquitard, the second aquitard and the aquifer are all mixtures of sand, gypsum and calcium carbonate with different proportions; the similar material used to simulate the Quaternary rock layer is soil; the first coal seam and the second coal seam are simulated using water bags, and multiple water bags are set. The spring needle mechanism simulates the excavation of coal seams in different areas by puncturing the water bags at different positions.

[0010] Furthermore, the sampling mechanism includes a first threaded tube that is threadedly connected to the monitoring hole. The outer surface of the first threaded tube is provided with an external thread that is adapted to the monitoring hole. The inside of the first threaded tube is provided with an internal thread. A threaded post is provided at the end of the first threaded tube away from the monitoring hole. The first threaded tube is sealed by the threaded post. When it is necessary to sample the polluted water, the threaded post can be removed and the polluted water will flow out from the first threaded tube.

[0011] A limiting ring plate is provided on the outside of the first threaded tube. The limiting ring plate can limit the size of the first threaded tube entering the box. A disc knob is provided at the end of the threaded column. The disc knob makes it easy for the experimenter to rotate the threaded column.

[0012] Furthermore, the sealing mechanism includes a second threaded tube that is threadedly connected to the monitoring hole. The outer surface of the second threaded tube is provided with an external thread that is adapted to the monitoring hole. The other end of the second threaded tube is threadedly connected to a threaded cylinder. The wiring port is located at the bottom of the threaded cylinder, and the signal line of the monitoring mechanism is led out from the wiring port.

[0013] Furthermore, the spring needle mechanism includes a sealing cylinder threadedly connected to the monitoring hole. The outer surface of the sealing cylinder is provided with an external thread that mates with the monitoring hole. The open end of the sealing cylinder faces the inside of the box. An annular baffle and a movable plate that slides in contact with the inner wall of the sealing cylinder are fixedly provided on the inner wall of the sealing cylinder. A spring is connected between the annular baffle and the movable plate. A needle is also provided on the side wall of the movable plate. The end of the needle away from the movable plate passes through the spring and the inside of the annular baffle. The side of the movable plate away from the spring is connected to one end of a slide rod. The other end of the slide rod slides through the bottom wall of the sealing cylinder and is connected to a pressure plate. When the pressure plate is pressed, the needle can penetrate into the box and puncture the water bag to simulate the occurrence of a goaf in the first or second coal seam. During the experiment, when the pressure plate is pressed, the pressure plate pushes the movable plate into the box through the slide rod. The movable plate drives the needle into the box and compresses the spring at the same time. When the needle enters the first or second coal seam, it will puncture the corresponding water bag. Then the pressure plate is released. Due to the restoring force of the spring, the needle can retract back into the sealing cylinder.

[0014] Furthermore, threaded holes are provided on the crossbar and the side wall of the box, and a frame is provided around the acrylic plate. The frame is provided with mounting holes, and bolts are used to install the acrylic plate onto the box through the mounting holes and threaded holes.

[0015] The frame sidewall is provided with a protruding strip that extends into the box and can block the gaps in the inner wall of the box, allowing water to pass through the middle of the bottom rock layer. There will be gaps between the similar material of the bottom rock layer and the inner wall of the box. In order to prevent the water injected from the bottom from not passing through the gaps, the protruding strip will block the inner wall of the box, thus blocking the bottom water and forcing the bottom water to pass through the inside of the bottom rock layer.

[0016] Furthermore, the monitoring mechanism includes a pressure sensor and a position sensor installed in the first and second waterproof layers. The signal lines of the pressure sensor and the position sensor pass through the sealing mechanism and are led out from the wiring port. In the experiment, the pressure sensor and the position sensor are used to detect the stress changes and displacement of similar materials in the first and second waterproof layers.

[0017] Furthermore, the monitoring holes corresponding to the Quaternary rock strata were sealed with bolts.

[0018] The present invention also provides a method for using an apparatus to simulate the sources of pollution and reactive erosion in closed mines, comprising the following steps:

[0019] S1. Before the experiment begins, the geological conditions are sorted out based on the hydrogeological data, borehole and stratigraphic profile data of the engineering site, and similar materials are used to adjust them to be consistent with the engineering conditions on site, so as to ensure that the geological laying and mechanical conditions are consistent with the site when the experiment begins.

[0020] S2. First, install acrylic panels on the side wall of the box from bottom to top. After laying the acrylic panel corresponding to the height of the stratum, put in a similar material for the corresponding stratum. For example, when laying the acrylic panel corresponding to the bottom rock stratum, put in a similar material for the bottom rock stratum, that is, a mixture of sand, gypsum and calcium carbonate in a certain proportion. Continue in this manner, from bottom to top, in the order of bottom rock stratum, first coal seam, first aquitard, second coal seam, second aquitard, aquifer and Quaternary rock stratum. After laying the similar material in one stage, continue to use transparent acrylic panels to support the box in the same way as above, and then continue to lay similar materials.

[0021] S3. During the laying process, pressure sensors and position sensors are pre-embedded in the first and second waterproof layers, and the signal lines are led out from the monitoring holes on the corresponding acrylic plates. In addition, when the aquifer and the second waterproof layer are laid to the protruding strip position, a layer of sealant is laid between the aquifer and the second waterproof layer to block the connection between the aquifer and the second waterproof layer, ensuring that there are no gaps between the internal rock layers and the outer wall of the box, so that water does not seep down or rise through the gaps, and the water pressure in the subsequent experiment can break through this layer of sealant.

[0022] S4. After the acrylic sheet is installed and each layer is laid, install the sampling mechanism, sealing mechanism, spring needle mechanism and bolts into the corresponding monitoring holes. The signal line of the monitoring mechanism is led out from the wiring port of the sealing mechanism. At the same time, start the monitoring mechanism. The pressure sensor and position sensor are started after the model is built and before the test. They are kept in monitoring state throughout the test until the equipment is turned off after the entire test is completed. The data is transmitted to the computer software through the sensor and data line.

[0023] S5. The experiment begins. By pressing the pressure plate, the pressure plate drives the needle to move into the box through the sliding rod and the moving plate. The needle will puncture the water bag inside the box as it moves inward, thus simulating coal seam excavation.

[0024] S6. After the water bag is punctured, it dries out, the upper rock mass sinks, a goaf appears in the middle, and cracks appear in the bottom rock layer. Then, water is continuously injected from the water injection hole at the bottom of the box. The pressure generated by the water at the bottom will eventually destroy the bottom rock layer. After the water at the bottom reaches the goaf, it reacts chemically with the rock material in the goaf, causing water pollution.

[0025] S7. When it is necessary to collect polluted water samples, unscrew the threaded column in the sampling mechanism, and the polluted water sample will flow out from the first threaded tube. The water sample is collected according to the excavation speed of the first and second coal seams.

[0026] S8. After the water injected into the bottom plate mixes and reacts with the water in the coal seam, the polluted water will continue to move upward. During the upward movement, it will break through the sealant between the aquifer 13 and the second water-proof layer 12. Finally, water samples are collected through the outlet. The chemical element changes during its migration process can also be determined. Samples are taken once every 24 hours, and are carried out simultaneously with the water sample collection in step S7.

[0027] Further, in step S7, the method for collecting water samples based on the excavation speed of the first and second coal seams is as follows: Puncture of the water bag represents the first stage of coal seam mining. At this time, the water sample needs a certain amount of time to mix and react with the injected water; therefore, the reaction time is set to 24 hours. Water samples are collected after 24 hours. Simultaneously, after the collection is completed, the second stage of coal seam excavation begins, i.e., the second water bag is punctured. Water samples are collected again after 24 hours. The third stage is then carried out, and so on, until the designated water bag is completely punctured.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. This device is equipped with bottom plate water intake and coal seam excavation. It can reproduce the movement of overlying strata in the coal seam during the coal seam excavation process, and also realize the process of the bottom plate aquifer being guided into the goaf under water pressure, thereby causing physicochemical reactions. In addition, this device has a simple structure, is easy to operate, has good sealing performance, and its components are replaceable. It can effectively realize the quantitative reduction of water pollution during the coal seam excavation process under dual erosion conditions, which helps to understand the mechanism of hydrochemical field changes of water sources under the influence of external conditions.

[0030] 2. During the coal seam excavation process, external probes can be inserted through monitoring holes to monitor the damage to the upper and lower rock strata of the coal seam. At the same time, the mechanism relationship can be further clarified by the changes in the chemical properties of water samples. This enables the monitoring of the source of polluted water and the entire process of reaction erosion after the mine is excavated and then closed. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0032] Figure 1 This is a schematic diagram of the structure of the side wall of the box in this invention.

[0033] Figure 2 This is a schematic diagram of the acrylic sheet structure in this invention.

[0034] Figure 3 This is a side sectional view of the internal structure of the box in this invention.

[0035] Figure 4 This is a schematic diagram of the external structure of the sampling mechanism in this invention.

[0036] Figure 5 This is a schematic diagram of the internal structure of the sampling mechanism in this invention.

[0037] Figure 6 This is a schematic diagram of the external structure of the sealing mechanism in this invention.

[0038] Figure 7 This is a schematic diagram of the internal structure of the sealing mechanism in this invention.

[0039] Figure 8 This is a schematic diagram of the external structure of the spring needle mechanism in this invention.

[0040] Figure 9 This is a schematic diagram of the internal structure of the spring needle mechanism in this invention.

[0041] The attached diagram is labeled as follows: 1. Box body; 2. Notch surface; 3. Crossbar; 4. Acrylic plate; 5. Monitoring hole; 6. Water inlet; 7. Water outlet; 8. Bottom stratum; 9. First coal seam; 10. First water-resistant layer; 11. Second coal seam; 12. Second water-resistant layer; 13. Aquifer; 14. Quaternary stratum; 15. Cable routing port; 16. First threaded pipe; 17. Threaded column; 18. Limiting ring plate; 19. Second threaded pipe; 20. Threaded cylinder; 21. Sealing cylinder; 22. Annular baffle; 23. Moving plate; 24. Spring; 25. Needle; 26. Slide rod; 27. Pressure plate; 28. Threaded hole; 29. ​​Frame; 30. Mounting hole; 31. Protruding strip. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0043] Example: Figures 1-9As shown, this embodiment provides a device for simulating pollution sources and reactive erosion in closed mines, including a box 1 with an opening at the top. Two opposite side walls of the box 1 are closed surfaces, and the other two opposite side walls are notched surfaces 2. Multiple crossbars 3 are equidistantly arranged on the notched surfaces 2. Acrylic plates 4 are arranged between adjacent crossbars 3. Multiple monitoring holes 5 are arranged on the acrylic plates 4, and internal threads are provided inside the monitoring holes 5. Multiple acrylic plates 4 close the corresponding notched surfaces 2. Water inlets 6 and outlets 7 are respectively provided at the bottom and top of the box 1. Inside the box 1, a bottom rock layer 8, a first coal seam 9, a first water-proof layer 10, a second coal seam 11, a second water-proof layer 12, an aquifer 13, and a Quaternary rock layer 14 are laid from bottom to top using similar materials. Monitoring mechanisms are provided in the first water-proof layer 10 and the second water-proof layer 12.

[0044] A detachable sampling mechanism is provided on the monitoring hole 5 corresponding to the aquifer 13 and the floor stratum 8. The sampling mechanism is used to sample the water in the aquifer 13 and the floor stratum 8. A detachable sealing mechanism is provided on the monitoring hole corresponding to the first water-proof layer 10 and the second water-proof layer 12. The sealing mechanism is provided with a wiring port 15. A detachable spring needle mechanism is provided on the monitoring hole 5 corresponding to the first coal seam 9 and the second coal seam 11. The spring needle mechanism is used to activate the first coal seam 9 and the second coal seam 11 to simulate the coal seam goaf. The monitoring hole 5 corresponding to the Quaternary stratum 14 is sealed with bolts.

[0045] The similar materials used to simulate the bottom rock strata 8, the first aquitard 10, the second aquitard 12 and the aquifer 13 are all mixtures of sand, gypsum and calcium carbonate with different proportions. The similar material used to simulate the Quaternary rock strata 14 is soil. The first coal seam 9 and the second coal seam 11 are simulated using water bags. Multiple water bags are set up, and the spring needle mechanism simulates the excavation of coal seams in different areas by puncturing the water bags at different positions.

[0046] The sampling mechanism includes a first threaded tube 16 that is threadedly connected to the monitoring hole 5. The outer surface of the first threaded tube 16 is provided with an external thread that matches the monitoring hole 5, and the inside of the first threaded tube 16 is provided with an internal thread. A threaded post 17 is provided at the end of the first threaded tube 16 away from the monitoring hole 5. The first threaded tube 16 is sealed by the threaded post 17. When it is necessary to sample the polluted water, the threaded post 17 can be removed, and the polluted water will flow out from the first threaded tube 16. A limiting ring plate 18 is provided on the outside of the first threaded tube 16. The limiting ring plate 18 can limit the size of the first threaded tube 16 entering the box 1. A disc knob is provided at the end of the threaded post 17, which makes it easy for the experimenter to rotate the threaded post 17.

[0047] The sealing mechanism includes a second threaded tube 19 that is threadedly connected to the monitoring hole 5. The outer surface of the second threaded tube 19 is provided with an external thread that is compatible with the monitoring hole 5. The other end of the second threaded tube 19 is threadedly connected to a threaded cylinder 20. The cable outlet 15 is located at the bottom of the threaded cylinder 20, and the signal line of the monitoring mechanism is led out from the cable outlet 15.

[0048] The spring needle mechanism includes a sealing cylinder 21 threadedly connected to the monitoring hole 5. The outer surface of the sealing cylinder 21 has an external thread that mates with the monitoring hole 5. The open end of the sealing cylinder 21 faces the interior of the housing 1. An annular baffle 22 and a movable plate 23 that slides against the inner wall of the sealing cylinder 21 are fixedly installed on the inner wall of the sealing cylinder 21. A spring 24 connects the annular baffle 22 and the movable plate 23. A needle 25 is also provided on the side wall of the movable plate 23. The end of the needle 25 away from the movable plate 23 passes through the spring 24 and the interior of the annular baffle 22. The side of the movable plate 23 away from the spring 24 is connected to one end of a sliding rod 26. The other end of the sliding rod 26 slides... The needle 25 passes through the bottom wall of the sealing cylinder 21 and is connected to a pressure plate 27. When the pressure plate 27 is pressed, the needle 25 can penetrate into the box 1 and puncture the water bag to simulate the occurrence of a goaf in the first coal seam 9 or the second coal seam 11. During the experiment, when the pressure plate 27 is pressed, the pressure plate 27 pushes the moving plate 23 into the box 1 through the slide rod 26. The moving plate 23 drives the needle 25 into the box 1 and compresses the spring 24 at the same time. When the needle 25 enters the first coal seam 9 or the second coal seam 11, it will puncture the corresponding water bag. Then the pressure plate 27 is released. Due to the restoring force of the spring 24, the needle 25 can retract back into the sealing cylinder 21.

[0049] The monitoring mechanism includes a pressure sensor and a position sensor installed in the first waterproof layer 10 and the second waterproof layer 12. The signal lines of the pressure sensor and the position sensor pass through the sealing mechanism and are led out from the wiring port 15. The signal lines need to be sealed with glue when they are led out. In the experiment, the pressure sensor and the position sensor are used to detect the stress changes and displacement of similar materials in the first waterproof layer 10 and the second waterproof layer 12.

[0050] Threaded holes 28 are provided on the crossbar 3 and the side wall of the box 1. A frame 29 is provided around the acrylic plate 4. The frame 29 is provided with mounting holes 30. Bolts are used to install the acrylic plate 4 onto the box 1 through the mounting holes 30 and the threaded holes 28. A protruding strip 31 is provided on the side wall of the frame 29. The protruding strip 31 extends into the inside of the box 1 and can block the gaps in the inner wall of the box 1, allowing water to pass through the middle of the bottom rock layer 8. There will be gaps between the similar material of the bottom rock layer 8 and the inner wall of the box 1. In order to prevent the water injected at the bottom from not passing through the gaps, the protruding strip 31 will block the inner wall of the box 1, thus blocking the bottom water and forcing the bottom water to pass through the inside of the bottom rock layer 8.

[0051] To better achieve the aforementioned effects, this invention also provides a method for using a device to simulate the pollution sources and reactive erosion of closed mines, comprising the following steps:

[0052] S1. Before the experiment begins, the geological conditions are sorted out based on the hydrogeological data, borehole and stratigraphic profile data of the engineering site, and similar materials are used to adjust them to be consistent with the engineering conditions on site, so as to ensure that the geological laying and mechanical conditions are consistent with the site when the experiment begins.

[0053] S2. First, install acrylic panels 4 sequentially from bottom to top on the side wall of the box body 1. After laying each acrylic panel 4 at the corresponding stratum height, put in a similar material for the corresponding stratum. For example, when laying the acrylic panel 4 corresponding to the bottom rock layer 8, put in a similar material for the bottom rock layer 8, that is, a mixture of sand, gypsum and calcium carbonate in a certain proportion. And so on, from bottom to top, in the order of bottom rock layer 8, first coal seam 9, first aquifer 10, second coal seam 11, second aquifer 12, aquifer 13 and Quaternary rock layer 14. After the similar materials of the first stage are laid, continue to use transparent acrylic panels to support the box body in the same way as above, and then continue to lay similar materials.

[0054] S3. During the laying process, pressure sensors and position sensors are pre-embedded in the first waterproof layer 10 and the second waterproof layer 12, and the signal lines are led out from the monitoring holes 5 on the corresponding acrylic plate 4. In addition, when the aquifer 13 and the second waterproof layer 12 are laid to the position of the protruding strip 31, a layer of sealant is laid between the aquifer 13 and the second waterproof layer 12 to block the connection between the aquifer 13 and the second waterproof layer 12, ensuring that there are no gaps between the internal rock layer and the outer wall of the box 1, so that the water does not seep down or rise through the gaps, and the water pressure in the subsequent experiment can break through this layer of sealant.

[0055] After S4, acrylic plate 4 are installed and each layer is laid, the sampling mechanism, sealing mechanism, spring needle mechanism and bolts are installed in the corresponding monitoring holes 5 respectively. The signal line of the monitoring mechanism is led out from the wiring port 15 of the sealing mechanism. At the same time, the monitoring mechanism is started. The pressure sensor and position sensor are started after the model is built and before the test. They are kept in monitoring state throughout the test until the equipment is turned off after the entire test is completed. The data is transmitted to the computer software through the sensor and data line.

[0056] S5. The experiment begins. By pressing the pressure plate 27, the pressure plate 27 drives the needle 25 to move into the box 1 through the slide rod 26 and the moving plate 23. The needle 25 moves inward and punctures the water bag inside the box 1 to simulate coal seam excavation.

[0057] S6. After the water bag is punctured, it dries out, the upper rock mass sinks, a goaf appears in the middle, and at the same time, cracks appear in the bottom rock layer 8. Then, water is continuously injected from the water injection hole 6 at the bottom of the box 1. The pressure generated by the water at the bottom will eventually destroy the bottom rock layer 8. After the water at the bottom reaches the goaf, it reacts chemically with the rock material in the goaf, causing water pollution.

[0058] S7. When it is necessary to collect polluted water samples, unscrew the threaded column 17 in the sampling mechanism. The polluted water sample flows out from the first threaded tube 16. The sampling frequency is supported by field data, that is, the water sample is collected according to the excavation speed of the first coal seam 9 and the second coal seam 11 (the frequency of water bag puncture). For example, after the water bag is punctured, it represents the first stage of coal seam mining. At this time, the water sample and the injected water need a certain amount of time to mix and react. Therefore, the reaction time is set to 24 hours. The water sample is collected after 24 hours. At the same time, after the collection is completed, the second stage of coal seam excavation is carried out, that is, the second water bag is punctured. After waiting for 24 hours, the water sample is collected. At the same time, the third stage is carried out, and so on, until the set water bag is completely punctured.

[0059] S8. After the water injected into the bottom plate mixes and reacts with the water in the coal seam, the polluted water will continue to move upward. During the upward movement, it will break through the sealant between the aquifer 13 and the second water-proof layer 12. Finally, water samples are collected through the outlet 7. The chemical element changes during its migration process can also be determined. Samples are taken once every 24 hours, which is carried out simultaneously with the water sample collection in step S7.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for simulating pollution sources and reactive erosion in closed mines, characterized in that, The box includes a box body (1), with an opening at the top. Two opposite side walls of the box body (1) are closed surfaces, and the other two opposite side walls are notched surfaces (2). Multiple horizontal bars (3) are equidistantly arranged on the notched surfaces (2). An acrylic plate (4) is arranged between adjacent horizontal bars (3). Multiple monitoring holes (5) are arranged on the acrylic plate (4). Multiple acrylic plates (4) close the corresponding notched surfaces (2). A water inlet (6) and a water outlet (7) are respectively arranged at the bottom and top of the box body (1). Inside the box body (1), a bottom rock layer (8), a first coal seam (9), a first water-proof layer (10), a second coal seam (11), a second water-proof layer (12), an aquifer (13), and a Quaternary rock layer (14) are laid from bottom to top using similar materials. A monitoring mechanism is arranged in the first water-proof layer (10) and the second water-proof layer (12). A detachable sampling mechanism is provided on the monitoring hole (5) corresponding to the aquifer (13) and the bottom rock layer (8), and the sampling mechanism is used to sample the water in the aquifer (13) and the bottom rock layer (8); A detachable sealing mechanism is provided on the monitoring hole corresponding to the first waterproof layer (10) and the second waterproof layer (12), and a wiring port (15) is provided on the sealing mechanism. A detachable spring needle mechanism is provided on the monitoring hole (5) corresponding to the first coal seam (9) and the second coal seam (11). The spring needle mechanism is used to stimulate the first coal seam (9) and the second coal seam (11) to mine, so as to simulate the coal seam goaf. The monitoring hole (5) is provided with an internal thread; The similar materials used to simulate the bottom rock layer (8), the first aquitard (10), the second aquitard (12) and the aquifer (13) are all mixtures of sand, gypsum and calcium carbonate with different proportions. The similar material used to simulate the Quaternary rock layer (14) is soil. The first coal seam (9) and the second coal seam (11) are simulated using water bags. Multiple water bags are set up, and the spring needle mechanism simulates the excavation of coal seams in different areas by puncturing water bags at different positions. The sampling mechanism includes a first threaded tube (16) that is threadedly connected to the monitoring hole (5). The first threaded tube (16) has an internal thread, and a threaded post (17) is provided at the end of the first threaded tube (16) away from the monitoring hole (5). A limiting ring plate (18) is provided on the outside of the first threaded tube (16), and a round knob is provided at the end of the threaded column (17); The sealing mechanism includes a second threaded tube (19) that is threaded to the monitoring hole (5), and a threaded cylinder (20) is threaded to the other end of the second threaded tube (19). The cable outlet (15) is located at the bottom of the threaded cylinder (20). The spring needle mechanism includes a sealing cylinder (21) threadedly connected to the monitoring hole (5). The opening end of the sealing cylinder (21) faces the inside of the housing (1). An annular baffle (22) and a movable plate (23) slidingly contacting the inner wall of the sealing cylinder (21) are fixedly provided on the inner wall of the sealing cylinder (21). A spring (24) is connected between the annular baffle (22) and the movable plate (23). A needle (25) is also provided on the side wall of the movable plate (23). The end of the moving plate (23) away from the spring (24) and the annular baffle (22) passes through the inside of the spring (24). The side of the moving plate (23) away from the spring (24) is connected to one end of the slide rod (26). The other end of the slide rod (26) slides through the bottom wall of the sealing cylinder (21) and is connected to a pressure plate (27). When the pressure plate (27) is pressed, the needle (25) can penetrate into the box (1) and puncture the water bag to simulate the occurrence of a goaf in the first coal seam (9) or the second coal seam (11).

2. The apparatus for simulating pollution sources and reactive erosion in closed mines according to claim 1, characterized in that, The crossbar (3) and the side wall of the box (1) are provided with threaded holes (28). The acrylic plate (4) is surrounded by a frame (29). The frame (29) is provided with mounting holes (30). Bolts are used to install the acrylic plate (4) onto the box (1) through the mounting holes (30) and the threaded holes (28). The side wall of the frame (29) is provided with a protruding strip (31), which extends into the interior of the box (1) and can block the gaps in the inner wall of the box (1) so that water can pass through the middle of the bottom rock layer (8).

3. The apparatus for simulating pollution sources and reactive erosion in closed mines according to claim 1, characterized in that, The monitoring mechanism includes a pressure sensor and a position sensor installed in the first waterproof layer (10) and the second waterproof layer (12). The signal lines of the pressure sensor and the position sensor pass through the sealing mechanism and are led out from the wiring port (15).

4. The apparatus for simulating pollution sources and reactive erosion in closed mines according to claim 1, characterized in that, The monitoring hole (5) corresponding to the Quaternary rock layer (14) is sealed with bolts.

5. A method of using an apparatus for simulating pollution sources and reactive erosion in a closed mine, the method being based on the apparatus for simulating pollution sources and reactive erosion in a closed mine as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Before the experiment begins, the geological conditions are sorted out based on the hydrogeological data, borehole and stratigraphic profile data of the engineering site, and similar materials are used to adjust them to be consistent with the engineering conditions on site, so as to ensure that the geological laying and mechanical conditions are consistent with the site when the experiment begins. S2. First, install acrylic plates (4) on the side wall of the box (1) from bottom to top. After laying the acrylic plate (4) at the corresponding stratum height, put in the similar material of the corresponding stratum. For example, when laying the acrylic plate (4) corresponding to the bottom rock layer (8), put in the similar material of the bottom rock layer (8). In this way, from bottom to top, in the order of bottom rock layer (8), first coal seam (9), first water-proof layer (10), second coal seam (11), second water-proof layer (12), aquifer (13) and Quaternary rock layer (14), after the similar material of the first stage is laid, continue to use transparent acrylic plates to support the box in the above manner, and then continue to lay similar materials. S3. During the laying process, pressure sensors and position sensors are pre-embedded in the first waterproof layer (10) and the second waterproof layer (12), and the signal lines are led out from the monitoring holes (5) on the corresponding acrylic plate (4); in addition, when the aquifer (13) and the second waterproof layer (12) are laid to the position of the protruding strip (31), a layer of sealant is laid between the aquifer (13) and the second waterproof layer (12) to block the connection between the aquifer (13) and the second waterproof layer (12), ensuring that there are no gaps between the internal rock layers and the outer wall of the box (1), so that the water does not seep down or rise through the gaps; After S4, acrylic plate (4) is installed and each layer is laid, the sampling mechanism, sealing mechanism, spring needle mechanism and bolt are installed in the corresponding monitoring hole (5) respectively. The signal line of the monitoring mechanism is led out from the wiring port (15) of the sealing mechanism, and the monitoring mechanism is started at the same time. S5. The experiment begins. By pressing the pressure plate (27), the pressure plate (27) drives the needle (25) to move into the box (1) through the slide rod (26) and the moving plate (23). The needle (25) will puncture the water bag inside the box (1) as it moves inward, thus simulating coal seam excavation. S6. After the water bag is punctured, it dries out, the upper rock mass sinks, a goaf appears in the middle, and at the same time, cracks appear in the bottom rock layer (8). Then, water is continuously injected from the water inlet (6) at the bottom of the box (1). The pressure generated by the water at the bottom will eventually destroy the bottom rock layer (8). After the water at the bottom reaches the goaf, it reacts chemically with the rock material in the goaf, causing water pollution. S7. When it is necessary to collect polluted water samples, unscrew the threaded column (17) in the sampling mechanism, and the polluted water sample flows out from the first threaded tube (16). The water sample is collected according to the excavation speed of the first coal seam (9) and the second coal seam (11). S8. After the water injected into the bottom plate mixes and reacts with the water in the first coal seam (9) and the second coal seam (11), the polluted water will continue to move upward. During the upward movement, it will break through the sealant between the aquifer (13) and the second water-proof layer (12). Finally, water samples are collected through the outlet (7). Similarly, the changes in chemical elements during its migration process can be determined. Samples are taken once every 24 hours, which is carried out synchronously with the water sample collection in step S7.

6. The method of using the device for simulating pollution sources and reactive erosion in a closed mine according to claim 5, characterized in that, In step S7, the method for collecting water samples based on the excavation speed of the first coal seam (9) and the second coal seam (11) is as follows: After the water bag is punctured, it represents the first stage of coal seam mining. At this time, the water sample and the injected water need a certain amount of time to mix and react. Therefore, the reaction time is set to 24 hours. After 24 hours, the water sample is collected. At the same time, after the collection is completed, the second stage of coal seam excavation is carried out, that is, the second water bag is punctured. After waiting for 24 hours, the water sample is collected. At the same time, the third stage is carried out, and so on, until the set water bag is completely punctured.

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