Rainfall infiltration physical similar simulation experiment platform and experiment method

Abstract

The present application relates to the technical field of rainfall seepage physical simulation, and particularly relates to a rainfall seepage physical simulation experiment platform and an experiment method, comprising a base, a photogrammetry point, a Perspex baffle, a platform frame, a similar simulation coal rock stratum, a seepage monitor, a computer, a second plastic water pipe, a wastewater tank, a camera, a moisture sensor and a filter assembly, and the top outer wall of the base is fixedly connected with the platform frame; the present application is simple in experiment work, convenient in operation, high in practicability and safety, and accurate in obtained data, is suitable for a coal seam mining simulation experiment process under rainfall conditions, can obtain physical parameters such as a migration law of overburden rock, a development law of mining fissure and rainfall seepage characteristics in a coal seam mining process under rainfall seepage conditions; simulation experiment data is monitored in real time through a three-dimensional photogrammetry system and a coal rock stratum seepage monitoring system, the influence of other factors on the similar simulation experiment data is reduced, and the stability and accuracy of the data are ensured.

Description

Technical Field

[0001] This invention relates to the field of physical similarity simulation technology for rainfall seepage, and in particular to an experimental platform and method for physical similarity simulation of rainfall seepage. Background Technology

[0002] The main characteristics of weakly cemented overburden movement caused by coal seam mining are: the roof strata are cut along the full thickness, the bedrock fracture angle is large, and mining-induced fractures directly affect the surface. When it rains, rainwater flows into the goaf and coal face through the mining-induced fractures. The flow of rainwater changes the permeability and penetration of the mining-induced fractures, causing changes in overburden stress and resulting in safety hazards such as water seepage, sand collapse, and frame collapse at the working face, which endanger the safe production of the working face. Physical similarity simulation experimental platforms are commonly used to study the movement law of overburden under coal seam mining conditions. However, traditional physical similarity simulation platforms do not take rainfall conditions into account in their design and construction. Therefore, existing physical similarity simulation experimental platforms cannot simulate conditions such as rainfall and seepage during coal seam mining. Summary of the Invention

[0003] The problem solved by this invention is to provide a physical similarity simulation experimental platform and method for rainfall seepage. The experiment is simple, easy to operate, highly practical, safe, and the data obtained is accurate. It is suitable for simulating coal seam mining under rainfall conditions and can obtain physical parameters such as the migration law of overlying strata, the development law of mining-induced fractures, and the characteristics of rainfall seepage during coal seam mining under rainfall seepage conditions. The simulation experimental data is monitored in real time through a three-dimensional photogrammetry system and a coal and rock strata seepage monitoring system, which reduces the influence of other factors on the similarity simulation experimental data and ensures the stability and accuracy of the data.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a physical similarity simulation experimental platform and method for rainfall seepage, comprising a base, photogrammetry points, acrylic baffles, a platform frame, a similar simulated coal and rock layer, a seepage monitoring instrument, a computer, a second plastic water pipe, a wastewater tank, a camera, a moisture sensor, and a filter assembly. The platform frame is fixedly connected to the top outer wall of the base, and acrylic baffles are fixedly connected to both outer walls of the platform frame. Photogrammetry points are distributed and installed on one outer wall of the acrylic baffles. A camera is installed on the outside of the base corresponding to the photogrammetry points. A moisture sensor is distributed and installed on one outer wall of the other acrylic baffle. A seepage monitoring instrument is installed on the outside of the base corresponding to the moisture sensor. A computer is connected to one side of the seepage monitoring instrument via wires. A second plastic water pipe is connected through the bottom outer wall of the platform frame. A wastewater tank is installed on the outer wall of the end of the second plastic water pipe, and a filter assembly is installed inside the wastewater tank.

[0005] Preferably, a pure water tank is installed outside the base, a water pump is installed on one side of the outer wall of the pure water tank, a first plastic water pipe is connected through the top outer wall of the water pump, PVC water pipes are installed on the inner walls of both sides of the platform frame, and one end of the first plastic water pipe is connected through the outer wall of the PVC water pipe, and atomizing spray heads are distributed at the bottom end of the PVC water pipe.

[0006] Preferably, the filtration assembly includes a motor, a rotating rod, a rotating plate, a rotating groove, a first rotating shaft, an adjusting plate, a second rotating shaft, a tilting filter frame, a silt filter screen, ear blocks, a third rotating shaft, and vibrators. A tilting filter frame is installed inside the wastewater tank, and a silt filter screen is embedded within the tilting filter frame. Vibrators are symmetrically installed on the top outer wall of the tilting filter frame. Second rotating shafts are fixedly connected to both outer walls of the tilting filter frame, and the other ends of the second rotating shafts are rotatably connected to the inner wall of the wastewater tank. Fixed connections are distributed on the bottom outer wall of the tilting filter frame. The wastewater tank is equipped with lugs, and a third rotating shaft is rotatably connected between the lugs. An adjusting plate is fixedly connected to one side of the third rotating shaft. Rotating plates are symmetrically installed inside the wastewater tank. Rotating grooves are opened on both sides of the rotating plates. A first rotating shaft is rotatably connected to the inner wall of both sides of the rotating groove, and one side of the first rotating shaft is fixed to the inner wall of the adjusting plate. A motor is embedded in the inner wall of one side of the wastewater tank. A rotating rod is fixedly connected to one end of the output shaft of the motor, and the other end of the rotating rod is rotatably connected to the inner wall of the wastewater tank. The rotating plate is fixed to the inner wall of the rotating rod.

[0007] Preferably, a drain pipe is connected through one side of the wastewater tank, and a valve is installed on the drain pipe.

[0008] Preferably, a partition plate is fixedly connected inside the wastewater tank, and a soil discharge pipe is connected through the wastewater tank on one side of the partition plate, with a threaded cap threaded to one end of the soil discharge pipe.

[0009] Preferably, the simulated coal and rock layers are laid in the platform frame, and multiple coal and rock layers with different rock types are set. Coal and rock layers with different rock types are simulated by using different proportions, and mica sheets are laid between each rock layer.

[0010] Preferably, the photogrammetry points are fixed on a similar simulated coal and rock layer with a grid of 10×10cm, the camera is placed 3-5m in front of the platform frame, and the electrical output terminal of the camera is electrically connected to the electrical input terminal of the computer.

[0011] Preferably, the electrical output terminal of the moisture sensor is electrically connected to the electrical input terminal of the seepage monitor, and the electrical output terminal of the seepage monitor is electrically connected to the electrical input terminal of the computer.

[0012] Preferably, an experimental method for a physical similarity simulation experimental platform for rainfall seepage includes the following steps: Step 1, platform construction and data calculation; Step 2, simulation platform construction; Step 3, coal and rock strata excavation simulation; Step 4, moisture detection setup; Step 5, rainfall simulation; Step 6, data acquisition and analysis.

[0013] In step one, the similarity ratio, occurrence characteristics, height and related physical properties of the simulated coal and rock strata are determined based on the borehole rock strata columnar section. The proportion and laying thickness of the similar simulation material are calculated based on the physical similarity simulation geometric similarity ratio.

[0014] In step two, the rock layers of the physical similarity simulation model are constructed from bottom to top according to the calculated coal-rock layer ratio and laying thickness. U-shaped channel steel is fixed on the front and back sides of the platform frame to form an internal space. The similar materials of each rock layer are fully mixed by a fully automatic mixer, poured into the platform frame space and spread flat. It is then compacted with a tamping hammer and its thickness is measured with a steel ruler. Mica sheets are laid between each coal-rock layer as a stratification. The coal-rock layers are laid upward in sequence until the coal-rock layer similarity simulation model is laid to the ground surface.

[0015] In step three, the completed coal and rock stratum similar simulation model needs to be left to stand for 7-14 days to confirm that the model is ready for subsequent simulated excavation. After that, remove the channel steel at the front and back of the platform frame, fix positioning rods on the channel steel in the horizontal and vertical directions of the platform frame, draw ink lines on the coal and rock stratum similar simulation model in the horizontal and vertical directions with adjacent ink lines spaced 10cm apart, and arrange photogrammetry points at the intersection of the ink lines. Install acrylic baffles at the front and back of the platform frame. The installation of acrylic baffles should be staggered from the coal seam to facilitate subsequent simulated excavation.

[0016] In step four, a moisture sensor is inserted into the small hole of the acrylic baffle on the back of the model, and the seepage monitor and computer are connected. A camera is placed in front of the model and connected to the computer. A PVC water pipe is placed above the platform frame and connected to the water pump, the first plastic water pipe and the pure water tank. Red dye is added to the pure water tank.

[0017] In step five, based on local weather data, the number of rainy days, duration, and amount of precipitation during coal seam mining are calculated, and the water pump suction capacity, atomizing nozzle spray pattern, and spray volume are adjusted.

[0018] In step six, after the relevant measurement and monitoring systems are debugged, a simulated coal seam excavation operation is carried out. During the simulated coal seam mining, rainfall is simulated and recorded with a camera until the coal seam is excavated. The displacement data and leakage data collected by the computer are then analyzed.

[0019] The beneficial effects of this invention are: simple experimental work, convenient operation, strong practicality, high safety, accurate data obtained, applicable to the simulation experiment of coal seam mining under rainfall conditions, and can obtain physical parameters such as the migration law of overburden, the development law of mining-induced fractures, and the characteristics of rainfall seepage during coal seam mining under rainfall seepage conditions;

[0020] The simulation experiment data is monitored in real time through a three-dimensional photogrammetry system and a coal and rock strata seepage monitoring system, which reduces the influence of other factors on similar simulation experiment data and ensures the stability and accuracy of the data;

[0021] The system employs a filtration structure that can perform preliminary filtration of wastewater and remove silt, ensuring the continuity of the filtration structure and improving the filtration effect. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0023] Figure 2 This is a perspective view of the other side of the invention;

[0024] Figure 3 This is a three-dimensional structural diagram of the wastewater tank of the present invention;

[0025] Figure 4 This is a front sectional view of the wastewater tank of the present invention;

[0026] Figure 5 This is a partial three-dimensional structural diagram of the wastewater tank of the present invention;

[0027] Figure 6 This is a process flow diagram of the present invention.

[0028] Legend:

[0029] 1. Base; 2. Pure water tank; 3. Water pump; 4. First plastic water pipe; 5. Photogrammetry point; 6. Acrylic baffle; 7. Platform frame; 8. Similar simulated coal and rock strata; 9. PVC water pipe; 10. Atomizing spray head; 11. Seepage monitor; 12. Computer; 13. Second plastic water pipe; 14. Wastewater tank; 15. Camera; 16. Moisture sensor; 17. Filter assembly; 18. Drain pipe; 9. Valve; 20. Isolation plate; 21. Drainage pipe; 22. Threaded cap; 1701. Motor; 1702. Rotating rod; 1703. Rotating plate; 1704. Rotating groove; 1705. First rotating shaft; 1706. Adjusting plate; 1707. Second rotating shaft; 1708. Tilting filter frame; 1709. Sediment filter screen; 17010. Ear block; 17011. Third rotating shaft; 17012. Vibrator. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] See Figures 1-2A physical similarity simulation experimental platform for rainfall seepage includes a base 1, photogrammetry points 5, acrylic baffles 6, a platform frame 7, a similar simulated coal and rock layer 8, a seepage monitoring instrument 11, a computer 12, a second plastic water pipe 13, a wastewater tank 14, a camera 15, and a moisture sensor 16. The platform frame 7 is fixedly connected to the top outer wall of the base 1. Acrylic baffles 6 are fixedly connected to both outer walls of the platform frame 7. Photogrammetry points 5 are distributed and installed on one outer wall of the acrylic baffles 6. A camera 15 is installed on the outside of the base 1 corresponding to the photogrammetry points 5. Moisture sensors 16 are distributed and installed on one outer wall of the other acrylic baffle 6. Sensor 16, a seepage monitor 11 is installed on the outside of the base 1 corresponding to the position of the moisture sensor 16, a computer 12 is installed on one side of the seepage monitor 11 via a wire, a second plastic water pipe 13 is connected through the bottom outer wall of the platform frame 7, a wastewater tank 14 is installed on the outer wall of the end of the second plastic water pipe 13, and a filter assembly 17 is installed inside the wastewater tank 14; a pure water tank 2 is installed outside the base 1, a water pump 3 is installed on one side of the outer wall of the pure water tank 2, a first plastic water pipe 4 is connected through the top outer wall of the water pump 3, PVC water pipes 9 are installed on the inner walls of both sides of the platform frame 7, and one end of the first plastic water pipe 4 is connected through... A water jet is connected to the outer wall of a PVC water pipe 9. Atomizing nozzles 10 are installed at the bottom of the PVC water pipe 9. The water volume is adjusted according to the rainfall. The water is then sprayed onto the simulated coal and rock layer 8 through the atomizing nozzles 10, and then permeates the simulated coal and rock layer 8. The simulated coal and rock layer 8 is laid within the platform frame 7, with multiple coal and rock layers of different rock types simulated using different proportions. Mica sheets are laid between each rock layer to make the simulated coal and rock layer 8 more closely resemble a real coal and rock layer, thus simulating the excavation of a real coal seam. Photogrammetry points 5 are 10×10cm. The grid points are fixed on the similar simulated coal and rock layer 8. The camera 15 is placed 3-5m in front of the platform frame 7. The electrical output terminal of the camera 15 is electrically connected to the electrical input terminal of the computer 12. The camera 15 takes pictures of different photogrammetry points 5 to record the parts through which the red clear water flows. The electrical output terminal of the moisture sensor 16 is electrically connected to the electrical input terminal of the seepage monitor 11. The electrical output terminal of the seepage monitor 11 is electrically connected to the electrical input terminal of the computer 12. The moisture sensor 16 is activated to detect the moisture in different coal and rock layers. Then the data is transmitted to the computer 12 through the seepage monitor 11.

[0033] Working principle: The red water in the pure water tank 2 is drawn by the water pump 3 and then injected into the PVC water pipe 9 through the first plastic water pipe 4. The water spray volume is adjusted according to the rainfall. The water is then sprayed onto the simulated coal and rock layer 8 through the atomizing nozzle 10 and then seeps into the simulated coal and rock layer 8. At this time, the moisture sensor 16 is activated to detect the moisture in different coal and rock layers. The data is then transmitted to the computer 12 through the seepage monitoring instrument 11. The camera 15 then takes pictures of different photogrammetry points 5 to record the parts through which the red water flows. The simulation experimental data is monitored in real time through the three-dimensional photogrammetry system and the coal and rock layer seepage monitoring system, which reduces the influence of other factors on the similar simulation experimental data and ensures the stability and accuracy of the data.

[0034] Example 2

[0035] See Figures 3-5The filter assembly 17 includes a motor 1701, a rotating rod 1702, a rotating plate 1703, a rotating groove 1704, a first rotating shaft 1705, an adjusting plate 1706, a second rotating shaft 1707, a tilting filter frame 1708, a silt filter screen 1709, an ear block 17010, a third rotating shaft 17011, and a vibrator 17012. The tilting filter frame 1708 is installed inside the wastewater tank 14, and the silt filter screen 1709 is embedded and connected inside the tilting filter frame 1708. The top of the tilting filter frame 1708... Vibrators 17012 are symmetrically installed on the outer wall of the filter frame 1708. Second rotating shafts 1707 are fixedly connected to both outer walls of the flip filter frame 1708, and the other end of each second rotating shaft 1707 is rotatably connected to the inner wall of the wastewater tank 14. Ear blocks 17010 are fixedly connected to the bottom outer wall of the flip filter frame 1708. A third rotating shaft 17011 is rotatably connected between the ear blocks 17010. An adjusting plate 1706 is fixedly connected to one side of the third rotating shaft 17011. Rotary... The rotating plate 1703 has rotating grooves 1704 on both sides. A first rotating shaft 1705 is rotatably connected to the inner walls of both sides of the rotating groove 1704. One side of the first rotating shaft 1705 is fixed to the inner wall of the adjusting plate 1706. A motor 1701 is embedded in the inner wall of one side of the wastewater tank 14. One end of the output shaft of the motor 1701 is fixedly connected to a rotating rod 1702, and the other end of the rotating rod 1702 is rotatably connected to the inner wall of the wastewater tank 14. The rotating plate 1703 is fixedly connected to the rotating shaft 1706. On the inner wall of the moving rod 1702; a drain pipe 18 is connected through to one side of the wastewater tank 14, and a valve 19 is installed on the drain pipe 18. Opening the valve 19 allows the filtered water to be discharged along the drain pipe 18; an isolation plate 20 is fixedly connected inside the wastewater tank 14, and a soil discharge pipe 21 is connected through to one side of the wastewater tank 14 located on the isolation plate 20. One end of the soil discharge pipe 21 is threadedly connected to a threaded cap 22. Unscrewing the threaded cap 22 allows the mud and sand located on one side of the isolation plate 20 to be discharged through the soil discharge pipe 21.

[0036] After the test is completed, the wastewater is injected into the wastewater tank 14 through the second plastic water pipe 13. At this time, it is filtered by the sediment filter screen 1709 on the flip filter frame 1708. After filtration, the motor 1701 is started, causing the rotating plate 1703 on the rotating rod 1702 to rotate to a specified angle. Then, the first rotating shaft 1705 in the rotating groove 1704 causes the adjusting plate 1706 to adjust its position. Finally, the third rotating shaft 17011 on the lug 17010 causes the flip filter frame 1708 to rotate. 08 flips the isolation plate 20, and then the vibrator 17012 is started to vibrate the flip filter frame 1708, causing the mud and sand to fall along the flip filter frame 1708 and the mud and sand filter screen 1709, and then fall onto the isolation plate 20. At this time, the valve 19 is opened to allow the filtered water to be discharged along the drain pipe 18. Then the threaded cap 22 is unscrewed to allow the mud and sand to be discharged through the soil discharge pipe 21. This process can perform preliminary filtration of sewage and clean the mud and sand, ensuring the continuity of the filter structure and improving the filtration effect.

[0037] Example 3

[0038] See Figure 6 An experimental method for a physical similarity simulation platform for rainfall seepage includes the following steps: Step 1, platform construction and data calculation; Step 2, simulation platform construction; Step 3, simulated excavation of coal and rock strata; Step 4, moisture detection and construction; Step 5, rainfall simulation; Step 6, data acquisition and analysis.

[0039] In step one, the similarity ratio, occurrence characteristics, height and related physical properties of the simulated coal and rock strata are determined based on the borehole rock strata columnar section. The proportion and laying thickness of the similar simulation material are calculated based on the physical similarity simulation geometric similarity ratio.

[0040] In step two, the rock layers of the physical similarity simulation model are constructed from bottom to top according to the calculated coal and rock layer ratio and laying thickness. U-shaped channel steel is fixed on the front and back sides of the platform frame 7 to form an internal space. The similar materials of each rock layer are fully mixed by a fully automatic mixer, poured into the space of the platform frame 7 and spread flat. It is compacted with a tamping hammer and its thickness is measured with a steel ruler. Mica sheets are laid between each coal and rock layer as a stratification. The coal and rock layers are laid upward in sequence until the coal and rock layer similarity simulation model is laid to the ground surface.

[0041] In step three, the completed coal and rock stratum similar simulation model needs to be left to stand for 7-14 days. After confirming that the model is ready for subsequent simulated excavation, remove the channel steel at the front and back of the platform frame. Fix positioning markers on the channel steel in the horizontal and vertical directions of the platform frame 7. Draw ink lines in the horizontal and vertical directions on the coal and rock stratum similar simulation model with adjacent ink lines spaced 10cm apart. Arrange photogrammetry points 5 at the intersection of the ink lines. Install acrylic baffles 6 at the front and back of the platform frame 7. The installation of acrylic baffles 6 should be staggered from the coal stratum to facilitate subsequent simulated excavation.

[0042] In step four, a moisture sensor 16 is inserted into the small hole of the acrylic baffle 6 on the back of the model, and the seepage monitor 11 and computer 12 are connected. A camera 15 is placed in front of the model and connected to the computer 12. The PVC water pipe 9 is placed above the platform frame and connected to the water pump 3, the first plastic water pipe 4 and the pure water tank 2. Red dye is added to the pure water tank 2.

[0043] In step five, based on local weather data, the number of rainy days, duration, and amount of precipitation during coal seam mining are calculated, and the water pump suction capacity, atomizing nozzle spray pattern, and spray volume are adjusted.

[0044] In step six, after the relevant measurement and monitoring systems are debugged, a simulated coal seam excavation operation is carried out. During the simulated coal seam mining, rainfall is simulated and recorded by camera 15 until the coal seam excavation is completed. The displacement data and leakage data collected by computer 12 are then analyzed.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A physical similarity simulation experimental platform for rainfall seepage, characterized in that, The system includes a base (1), photogrammetry points (5), acrylic baffles (6), a platform frame (7), a simulated coal and rock strata (8), a seepage monitoring instrument (11), a computer (12), a second plastic water pipe (13), a wastewater tank (14), a camera (15), and a moisture sensor (16). The platform frame (7) is fixedly connected to the top outer wall of the base (1), and acrylic baffles (6) are fixedly connected to both outer walls of the platform frame (7). Photogrammetry points (5) are distributed and installed on one outer wall of the acrylic baffles (6). The base (1) is connected to the photogrammetry points (5) on the outside of the platform frame (7). A camera (15) is installed at the measuring point (5). Moisture sensors (16) are distributed on one side of the outer wall of another acrylic baffle (6). A seepage monitor (11) is installed on the outside of the base (1) corresponding to the moisture sensor (16). A computer (12) is installed on one side of the seepage monitor (11) via a wire. A second plastic water pipe (13) is connected through the bottom outer wall of the platform frame (7). A wastewater tank (14) is installed on the outer wall of the end of the second plastic water pipe (13). A filter assembly (17) is installed inside the wastewater tank (14).

2. The physical similarity simulation experimental platform for rainfall seepage according to claim 1, characterized in that, A pure water tank (2) is installed outside the base (1). A water pump (3) is installed on one side of the outer wall of the pure water tank (2). A first plastic water pipe (4) is connected through the top outer wall of the water pump (3). PVC water pipes (9) are installed on the inner walls of both sides of the platform frame (7). One end of the first plastic water pipe (4) is connected through the outer wall of the PVC water pipe (9). Atomizing spray heads (10) are distributed at the bottom of the PVC water pipe (9).

3. The rainfall seepage physical similarity simulation experimental platform according to claim 1, characterized in that, The filter assembly (17) includes a motor (1701), a rotating rod (1702), a rotating plate (1703), a rotating groove (1704), a first rotating shaft (1705), an adjusting plate (1706), a second rotating shaft (1707), a tilting filter frame (1708), a silt filter screen (1709), an ear block (17010), a third rotating shaft (17011), and a vibrator (17012). The tilting filter frame is installed inside the wastewater tank (14). (1708), a silt filter screen (1709) is embedded in the flip filter frame (1708), a vibrator (17012) is symmetrically installed on the top outer wall of the flip filter frame (1708), a second rotating shaft (1707) is fixedly connected to both outer walls of the flip filter frame (1708), and the other end of the second rotating shaft (1707) is rotatably connected to the inner wall of the wastewater tank (14), and the bottom of the flip filter frame (1708) is... Ear blocks (17010) are fixedly connected to the wall. A third rotating shaft (17011) is rotatably connected between the ear blocks (17010). An adjusting plate (1706) is fixedly connected to one side of the third rotating shaft (17011). Rotating plates (1703) are symmetrically installed inside the wastewater tank (14). Rotating grooves (1704) are opened on both sides of the rotating plates (1703). A first rotating plate is rotatably connected to the inner wall of both sides of the rotating grooves (1704). A shaft (1705) is fixed on one side of the first rotating shaft (1705) to the inner wall of the adjusting plate (1706). A motor (1701) is embedded in the inner wall of one side of the wastewater tank (14). One end of the output shaft of the motor (1701) is fixed to a rotating rod (1702), and the other end of the rotating rod (1702) is rotatably connected to the inner wall of the wastewater tank (14). The rotating plate (1703) is fixed to the inner wall of the rotating rod (1702).

4. The rainfall seepage physical similarity simulation experimental platform according to claim 1, characterized in that, A drain pipe (18) is connected through one side of the wastewater tank (14), and a valve (19) is installed on the drain pipe (18).

5. The rainfall seepage physical similarity simulation experimental platform according to claim 1, characterized in that, An isolation plate (20) is fixedly connected inside the wastewater tank (14). A soil discharge pipe (21) is connected through the wastewater tank (14) on one side of the isolation plate (20). A threaded cap (22) is threadedly connected to one end of the soil discharge pipe (21).

6. The physical similarity simulation experimental platform for rainfall seepage according to claim 1, characterized in that, The simulated coal and rock layer (8) is laid in the platform frame (7), and multiple coal and rock layers with different rock types are set. Coal and rock layers with different rock types are simulated by using different proportions, and mica sheets are laid between each rock layer.

7. The rainfall seepage physical similarity simulation experimental platform according to claim 1, characterized in that, The photogrammetry point (5) is fixed on the similar simulated coal and rock layer (8) with a grid of 10×10cm. The camera (15) is placed 3-5m in front of the platform frame (7). The electrical output terminal of the camera (15) is electrically connected to the electrical input terminal of the computer (12).

8. The physical similarity simulation experimental platform for rainfall seepage according to claim 1, characterized in that, The electrical output terminal of the moisture sensor (16) is electrically connected to the electrical input terminal of the seepage monitor (11), and the electrical output terminal of the seepage monitor (11) is electrically connected to the electrical input terminal of the computer (12).

9. The experimental method for a physical similarity simulation experimental platform for rainfall seepage according to any one of claims 1-8, characterized in that, The process includes the following steps: Step 1, platform setup and data calculation; Step 2, simulation platform setup; Step 3, coal and rock strata simulation excavation; Step 4, moisture detection setup; Step 5, precipitation simulation; Step 6, data acquisition and analysis. In step one, the similarity ratio, occurrence characteristics, height and related physical properties of the simulated coal and rock strata are determined based on the borehole rock strata columnar section. The proportion and laying thickness of the similar simulation material are calculated based on the physical similarity simulation geometric similarity ratio. In step two, the rock layers of the physical similarity simulation model are built from bottom to top according to the calculated coal and rock layer ratio and laying thickness. U-shaped channel steel is fixed on the front and back sides of the platform frame (7) to form an internal space. The similar materials of each rock layer are fully mixed by a fully automatic mixer, poured into the space of the platform frame (7) and spread flat. It is compacted with a tamping hammer and its thickness is measured with a steel ruler. Mica sheets are laid between each coal and rock layer as a stratification. The coal and rock layers are laid upward in sequence until the coal and rock layer similarity simulation model is laid to the ground surface. In step three, the coal and rock strata similar simulation model that has been laid out needs to be left to stand for 7-14 days. After confirming that the model can be used for subsequent simulated excavation, the channel steel in front and behind the platform frame is removed. Positioning rods are fixed on the channel steel in the horizontal and vertical directions of the platform frame (7). Ink lines are drawn on the coal and rock strata similar simulation model in the horizontal and vertical directions with an interval of 10cm between adjacent ink lines. Photogrammetry points (5) are arranged at the intersection of ink lines. Acrylic baffles (6) are installed in front and behind the platform frame (7). The installation of acrylic baffles (6) needs to be staggered from the coal strata to facilitate subsequent simulated excavation. In step four, a moisture sensor (16) is inserted into the small hole of the acrylic baffle (6) on the back of the model, and a seepage monitor (11) and a computer (12) are connected. A camera (15) is placed in front of the model and connected to the computer (12). A PVC water pipe (9) is placed above the platform frame and connected to a water pump (3), a first plastic water pipe (4) and a pure water tank (2). Red dye is added to the pure water tank (2). In step five, based on local weather data, the number of rainy days, duration, and amount of precipitation during coal seam mining are calculated, and the water pump suction capacity, atomizing nozzle spray pattern, and spray volume are adjusted. In step six, after the relevant measurement and monitoring system is debugged, a simulated coal seam excavation operation is carried out. During the simulated coal seam mining, rainfall is simulated and recorded with a camera (15) until the coal seam excavation is completed. The displacement and leakage data collected by the computer (12) will be analyzed in subsequent steps.

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