Coal mining subsidence area water and soil loss similar simulation device and experiment method

Abstract

The invention relates to the technical field of mining engineering, environmental geotechnical engineering and water and soil conservation, and particularly discloses a coal mining subsidence area water and soil loss similar simulation device and experimental method.The coal mining subsidence area water and soil loss similar simulation device comprises a support and an experimental box, the experimental box is installed on the support, an experimental soil body is arranged in the experimental box, and a subsidence crack simulation system is arranged in the experimental soil body; the top of the experiment box is matched with a rainfall system; the subsidence fracture simulation system comprises a middle box body arranged in the middle of the experiment box, the middle box body is embedded in an experiment soil body of the experiment box, an experiment soil body is also arranged in the middle box body, and one or more fracture plates are embedded in the middle box body in a matched mode. The method can physically reproduce a complete erosion path of'surface runoff collection-fracture preferential flow-lateral matrix infiltration 'of the subsidence area, and accurately quantify the effect of the fracture in acceleration of water and soil loss.

Description

Technical Field

[0001] This invention relates to the fields of mining engineering, environmental geotechnical engineering, and soil and water conservation, and in particular to an experimental apparatus and method for physically simulating the soil and water loss process under the synergistic effect of surface runoff and soil preferential flow during the dynamic subsidence of coal mining subsidence areas. Background Technology

[0002] Coal mining causes the movement of overlying strata, triggering surface subsidence and creating widespread depressions and surface fissures. This dramatic change in topography and soil structure has fundamentally altered the region's hydrological cycle. Surface runoff converges in the depressions, increasing its scouring capacity; simultaneously, runoff rapidly infiltrates through opening fissures, activating existing or newly formed preferential flow channels in the soil, forming a rapid erosion path coupled with surface conditions, greatly exacerbating soil erosion and groundwater pollution risks.

[0003] Currently, research on this problem largely relies on field surveys and numerical simulations. Field surveys are limited by natural conditions, making it difficult to control variables and capture instantaneous processes, and are also costly and time-consuming. While numerical simulations are flexible, the establishment of models and the determination of parameters heavily depend on an accurate understanding of the physical processes. However, the mechanism of the complex coupled process of subsidence-fracture-preferential flow is not yet fully clear, leading to uncertainties in the simulation results.

[0004] Indoor physical simulation is an effective means to compensate for the shortcomings of the two methods mentioned above. However, most existing soil erosion simulation experimental devices are designed for natural slopes and cannot simulate the dynamic and non-uniform surface subsidence caused by mining. They also lack the ability to actively introduce and control preferential flow paths, thus making it difficult to realistically reproduce the soil erosion phenomena unique to coal mining subsidence areas. Therefore, developing a dedicated experimental device and method that can integrate the simulation of dynamic subsidence, surface runoff, and preferential soil flow is urgent and of great significance for revealing the erosion mechanism, validating numerical models, and guiding ecological restoration practices. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and to propose a similar simulation device and experimental method for soil and water loss in coal mining subsidence areas.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A similar simulation device for soil and water loss in coal mining subsidence areas includes a support frame and an experimental box. The experimental box is installed on the support frame and contains experimental soil. The experimental soil contains a subsidence crack simulation system, and a rainfall system is matched on the top of the experimental box. The subsidence fissure simulation system includes an intermediate box set in the middle of the experimental chamber. The intermediate box is buried in the experimental soil of the experimental chamber. The interior of the intermediate box is also filled with experimental soil, and one or more fissure plates are matched and buried. Each of the multiple fissure plates is matched with a driving mechanism. The lifting and lowering of the multiple fissure plates can be controlled by the driving mechanism, and fissure bodies are generated in the corresponding experimental soil. The top of the intermediate box is covered with a plastic film, and the multiple fissure plates penetrate the plastic film and are set inside the intermediate box. The rainfall system includes several water pipes evenly arranged above the experimental chamber, and several full-cone nozzles evenly arranged on the water pipes. The water pipes can carry water, and the full-cone nozzles can spray liquid water onto the top of the experimental chamber.

[0007] Preferably, the system also includes a water collection system, which includes several collection buckets. The lower part of one side wall of the experimental chamber is provided with a runoff outlet, and the bottom is provided with a seepage outlet. The runoff outlet and the seepage outlet are respectively connected to two collection buckets through water inlet pipes. The two collection buckets are used to collect surface runoff flowing from the runoff outlet and underground seepage flowing from the seepage outlet, respectively.

[0008] Preferably, the bottom of the intermediate box is connected to a funnel, and the bottom of the funnel is connected to a collection bucket via a water inlet pipe. The collection bucket is used to collect the preferred flow from the bottom of the intermediate box, and the bottom of the experimental box is provided with a bottom slot for the water inlet pipe to pass through.

[0009] Preferably, the system also includes a data acquisition system, which comprises: flow rate and velocity sensors deployed on the surface of the experimental soil and at the runoff outlet; an array of soil moisture sensors and a pore water pressure sensor deployed at different depths and horizontal positions on both sides of the fracture body; a high-definition camera device positioned directly in front of the experimental chamber; a turbidimeter installed in the collection bucket and an electronic balance at the bottom of the collection bucket; a laser rain spectrometer deployed on the surface of the experimental soil; and an ultrasonic detector for detecting the geometric dimensions of the fracture body.

[0010] Preferably, the experimental box is made of high-strength steel, the front of the experimental box is a transparent acrylic plate, and the interior of the experimental box is laid with a gravel drainage layer and a geotextile filter layer from bottom to top. The experimental soil is placed on top of the geotextile filter layer. The experimental soil is reconstituted soil filled in layers according to the original soil structure, or directly taken from the original soil of the coal mining subsidence area.

[0011] Preferably, the support includes a base frame, a bottom frame on top of the base frame, a fixed connection between the bottom of the experimental box and the bottom frame, a rotatable connection between one end of the bottom frame and the base frame, an arc-shaped slide rail symmetrically fixed at one end of the base frame, and a sliding connection between the other end of the bottom frame and two arc-shaped slide rails via two sliders. A circular hole is provided in the middle of the slider, and several notches are provided at equal intervals on both sides of the arc-shaped slide rails. A pin can be inserted into the circular hole, and a positioning rod is provided at both ends of the pin. The two positioning rods can be fitted into the two notches respectively. The pin can position the bottom frame and the arc-shaped slide rails. A hydraulic cylinder for driving the bottom frame to rotate is installed on the base frame.

[0012] Preferably, the water pipe is detachably and fixedly mounted on the mounting frame, which can be supported on the ground by a support column, and the water pipe can be connected to the water pump.

[0013] Preferably, the driving mechanism includes a fixed frame, which is detachably fixed to the top of the experimental box. The bottom of the fixed frame is provided with a waist-shaped hole, and the middle of the fixed frame is provided with multiple electric telescopic rods. The telescopic rods are controlled by telescopic guide rods. The telescopic guide rods are vertically downward and telescopically connected to a connecting rod. The top of the slit plate is provided with a threaded hole, and the end of the connecting rod can be threadedly connected to the threaded hole. The other end of the electric telescopic rod can be fixedly connected to the waist-shaped hole by bolts.

[0014] The experimental method for the above-mentioned device includes the following steps: S1: A gravel drainage layer and a geotextile filter layer are laid from top to bottom inside the test chamber. Then, the test soil is filled in layers above the geotextile filter layer, and the density and moisture content of the test soil are controlled. When the filling reaches the design height, an intermediate box is buried in the middle of the test chamber. The intermediate box is buried in the test soil of the test chamber. The intermediate box also contains the same number of test soil layers as the test soil in the test chamber, and a slit plate is buried in it. The slit plate is matched with a driving mechanism. The top of the intermediate box is covered with a plastic film, and the slit plate penetrates the plastic film and is set inside the intermediate box. S2: Then, the lifting and lowering of multiple fracture plates can be controlled by the drive mechanism to generate a fracture body with controllable position, depth and width in the experimental soil of the intermediate box. S3: Activate the rainfall system to simulate rainfall by injecting pigment into the generated fracture body. The pigment is used to trace the preferential flow. S4: During the experiment, the surface runoff time, runoff and seepage process lines were recorded simultaneously, runoff and seepage samples were collected to measure sediment content, and the spatiotemporal dynamic distribution of water in the preferential flow simulation system was monitored. At the same time, images of surface erosion and water flow processes in the fissure body were recorded. S5: After the experiment, analyze all the collected data; then drain the water from the box, take out the experimental soil from the middle box, and observe and record the preferential flow path morphology shown by the tracer, the soil erosion characteristics of the fracture wall, and the depth and range of lateral water infiltration.

[0015] Preferably, in step S2, the soil erosion process under different settlement intensities and multi-fracture network conditions can be simulated by changing the position and number of fracture plates or selecting fracture plates of different widths.

[0016] Compared with the prior art, the beneficial effects of the present invention are: For the first time, dynamic subsidence simulation is combined with active priority flow simulation, which can physically reproduce the key processes of soil and water loss in the coal mining subsidence area, and the mechanism is clear and intuitive.

[0017] High controllability: Experimental conditions (such as subsidence velocity and range, rainfall characteristics, and preferential flow location) are completely controllable, and single-factor or multi-factor sensitivity analysis can be performed, which is unmatched by field experiments.

[0018] Highly comprehensive: It integrates multiple sensors and image recording devices, enabling it to simultaneously acquire multi-physics field information from the surface and underground, providing rich and accurate data support for mechanism research and model verification.

[0019] Highly practical: This device and method can be used to test the effectiveness of different soil and water conservation measures (such as crack filling materials and vegetation types) in suppressing this coupled erosion, and has direct application value. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is an isometric view of the present invention; Figure 2 This is a front sectional view of the experimental box of the present invention; Figure 3 This is a schematic diagram of the structure of the intermediate box of the present invention; Figure 4 This is a schematic diagram of the drive mechanism of the present invention mounted on the experimental box; Figure 5 This is a schematic diagram of the drive mechanism of the present invention; Figure 6 This is a schematic diagram of the structure of the pin and positioning rod of the present invention.

[0022] 1. Support frame; 101. Base frame; 102. Base frame; 103. Arc-shaped slide rail; 104. Pin; 105. Positioning rod; 106. Hydraulic cylinder; 2. Experimental chamber; 201. Runoff outlet; 202. Seepage outlet; 203. Crushed stone drainage layer; 204. Geotextile filter layer; 205. Experimental soil; 3. Water pipe; 4. Intermediate box; 401. Funnel; 5. Drive mechanism; 501. Fixing frame; 502. Waist-shaped hole; 503. Electric telescopic rod; 504. Telescopic smooth rod; 505. Connecting rod; 6. Fissure plate; 601. Threaded hole; 602. Fissure body; 7. Collection bucket. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] like Figures 1-6 As shown, the simulation device of the present invention mainly includes the following parts: Support 1 and Experiment Box 2: Experiment Box 2 is made of high-strength steel and transparent acrylic sheet. The front is made of transparent acrylic sheet, and an acrylic sheet transparent observation window can also be embedded in the front of Experiment Box 2 for easy observation. High-strength steel serves as the frame and side walls, and the sides of the box are designed with sliding grooves to facilitate the use of movable baffles to cut the soil after the experiment. The grooves also provide sliding positioning for the movable baffles. The dimensions of Experiment Box 2 are (length × width × height) 2.0m × 0.5m × 0.8m.

[0025] The support frame 1 includes a base frame 101, with a bottom frame 102 on top of the base frame 101. The bottom of the experimental box 2 is fixedly connected to the bottom frame 102. One end of the bottom frame 102 is rotatably connected to the base frame 101. One end of the base frame 101 is symmetrically fixed with arc-shaped slide rails 103. The other end of the bottom frame 102 is slidably connected to two arc-shaped slide rails 103 via two sliders. The sliders have a round hole in the middle, and the arc-shaped slide rails 103 have several notches equidistantly arranged on both sides. The round holes are suitable for inserting pins 104. The pin 104 has positioning rods 105 at both ends. The two positioning rods 105 can be inserted into two notches respectively, providing three-point positioning. The pin 104 can position the base frame 102 and the arc-shaped slide rail 103. A hydraulic cylinder 106 is installed on the base frame 101 to drive the base frame 102 to rotate. The two ends of the hydraulic cylinder 106 are rotatably connected to the base frame 101 and the bottom of the base frame 102 respectively. The hydraulic cylinder 106 can control the active rotation and adjustment of the base frame 102 and the corresponding experimental chamber 2. The tilt angle adjustment range of the experimental chamber 2 is 0°-30°, which can simulate different terrain slopes. Specifically... Figure 1 and Figure 6As shown. Experimental chamber 2 contains experimental soil 205, which is equipped with a settlement and crack simulation system. A rainfall system is also installed on the top of experimental chamber 2, as detailed below. Figure 1 , Figure 2 As shown.

[0026] A subsidence fracture simulation system, used to collect preferential flow, includes an intermediate box 4 located in the middle of experimental chamber 2. The sidewall structure of the intermediate box 4 is the same as that of experimental chamber 2, i.e., the front side of the intermediate box 4 is a transparent acrylic plate. The size of the intermediate box 4 is smaller than that of experimental chamber 2. The intermediate box 4 is buried within the experimental soil 205 of experimental chamber 2, and the front side of the intermediate box 4 is attached to the front side of experimental chamber 2, allowing the internal condition of the intermediate box 4 to be observed through the front side of experimental chamber 2. Experimental soil 205 is also set inside the intermediate box 4, and one or more fracture plates 6 are embedded therein. Each fracture plate 6 is equipped with a drive mechanism 5, which controls the raising and lowering of the multiple fracture plates 6, generating fracture bodies 602 in the corresponding experimental soil 205. The top of the intermediate box 4 is covered with a plastic film, and the multiple fracture plates 6 penetrate the plastic film and are set inside the intermediate box 4. (Details follow...) Figure 2 and Figure 3 As shown.

[0027] It also includes a water collection system for collecting priority flow, seepage, and surface runoff. The water collection system includes several collection tanks 7. The lower part of one side wall of the experimental box 2 is provided with a runoff outlet 201 and the bottom is provided with a seepage outlet 202. The runoff outlet 201 and the seepage outlet 202 are respectively connected to the two collection tanks 7 through water inlet pipes. The two collection tanks 7 are used to collect the surface runoff flowing out of the runoff outlet 201 and the underground seepage flowing out of the seepage outlet 202, respectively.

[0028] Internal structure of experimental box 2: as follows Figure 2 As shown, a 5cm thick layer of gravel drainage 203 is first laid at the bottom of experimental chamber 2, covered with a geotextile filter layer 204 to prevent soil erosion. Then, undisturbed soil directly taken from the coal mining subsidence area or reconstituted soil layered according to the undisturbed soil structure is filled in layers as experimental soil 205. Each layer needs to be compacted after filling to achieve the preset unit weight, i.e., controlling the density and moisture content of the experimental soil 205 to be as consistent as possible. Furthermore, the number of layers of experimental soil 205 inside the intermediate chamber 4 is the same as that inside experimental chamber 2, and both layers maintain the same density and moisture content as much as possible.

[0029] The bottom of the intermediate chamber 4 is connected to a funnel 401, which contains a filter screen, similar to the effect of the geotextile filter layer 204, providing a certain filtration effect. The bottom of the funnel 401 is connected to a collection bucket 7 via a water inlet pipe. The collection bucket 7 is used to collect the preferred flow from the bottom of the intermediate chamber 4. The bottom of the experimental chamber 2 has a bottom slot for the water inlet pipe to pass through, and a sealing ring is installed in the slot to achieve a leak-proof sealing effect.

[0030] The drive mechanism 5 includes a fixed frame 501, which is detachably fixed to the top of the experimental chamber 2. The bottom of the fixed frame 501 is provided with a waist-shaped hole 502. The middle of the fixed frame 501 is provided with multiple electric telescopic rods 503. The telescopic rods 503 are controlled by telescopic rods 504. The telescopic rods 504 are vertically downward and telescopically connected to a connecting rod 505. The top of the slit plate 6 is provided with a threaded hole 601. The end of the connecting rod 505 can be threadedly connected to the threaded hole 601. The other end of the electric telescopic rod 503 can be fixedly connected to the waist-shaped hole 502 by bolts. Both the fixed frame 501 and the electric telescopic rod 503 are detachable. The number of electric telescopic rods 503 can be changed according to needs. The telescopic smooth rod 504 and the corresponding connecting rod 505 are telescopically limited. The connecting rod 505 rotates along the axis and will not move after reaching the maximum telescopic amount. After the end of the connecting rod 505 is threadedly connected to the threaded hole 601 of the fracture plate 6, the corresponding electric telescopic rod 503 can control the retraction of the telescopic smooth rod 504, that is, it can control the raising and lowering of the corresponding fracture plate 6. Furthermore, it is not limited to pulling out the fracture plate 6 through the drive mechanism 5; the corresponding fracture plate 6 can also be pulled out from the experimental soil 205 manually using pliers.

[0031] Rainfall system: Employing multiple evenly arranged full-cone nozzles supplied by a constant-pressure water pump, the system comprises several evenly arranged water pipes 3, each with an evenly arranged full-cone nozzle. The water pipes 3 are connected to the water pump via flexible hoses. The water pump, a constant-pressure pump, can be placed in a water tank. When powered on, the pump pumps water into the flexible hoses, which then distribute the water to the various water pipes 3, ultimately spraying it out through the nozzles. The water pipes 3 are detachably and securely mounted on a mounting frame, which can be configured for vertical lifting and can be supported on the ground by pillars. The rainfall system can simulate large-scale uniform rainfall and water infiltration on the experimental soil 205. Furthermore, by adjusting the water pressure and nozzle combinations, simulated rainfall of varying intensities and uniformities can be achieved.

[0032] The system also includes a data acquisition system comprising: flow rate and velocity sensors deployed on the surface of the experimental soil 205 and at the runoff outlet 201 for real-time monitoring of runoff; an array of soil moisture sensors and pore water pressure sensors deployed at different depths and horizontal positions on both sides of the fracture body 602 for monitoring the lateral migration of water from the fracture body 602 to the matrix; a high-definition camera positioned directly in front of the experimental chamber 2 for recording dynamic images of surface runoff development, soil erosion, and water flow processes within the fracture body 602; a turbidimeter installed in the collection tank 7 and an electronic balance at the bottom of the collection tank 7; a laser rain spectrometer deployed on the surface of the experimental soil 205 for calibrating rainfall characteristics; and an ultrasonic detector for detecting the geometric dimensions of the fracture body 602. It should be noted that all of the above sensors are commercially available, and the system is not limited to these sensors; additional data acquisition-related sensors can also be installed.

[0033] The electronic balance can weigh in real time, and can periodically remove the water sample collected in the collection bucket 7 during the collection process, and determine the sand content using the drying method.

[0034] The experimental procedure is as follows: S1: Preparation stage. Adjust the tilt angle of experimental chamber 2 to 5°. Lay the gravel drainage layer 203 and geotextile filter layer 204 according to the design. Then, fill the experimental soil 205 in layers on top of the geotextile filter layer 204, and control the density and moisture content of the experimental soil 205. When the filling reaches the design height, bury the intermediate box 4 in the experimental soil 205. The intermediate box 4 is also equipped with the same number of layers of experimental soil 205 as the experimental soil 205 in experimental chamber 2, and a cracked plate 6 is buried in it. The cracked plate 6 is matched with the driving mechanism 5. The top of the intermediate box 4 is covered with a plastic film, and the cracked plate 6 penetrates the plastic film and is set inside the intermediate box 4.

[0035] S2: Settlement simulation. After the soil has consolidated and stabilized, and after a period of time, the lifting and lowering of multiple fracture plates 6 can be controlled by the drive mechanism 5 to generate a fracture body 602 with controllable position, depth and width in the experimental soil 205 of the intermediate box 4.

[0036] S3: Coupling Experiment. Maintaining the post-settlement state, activate the rainfall system to simulate a rainstorm with an intensity of 60 mm / h. Ten minutes after the rainfall begins, inject tracer directly into the fracture body 602, i.e., inject pigment. The tracer consists of brilliant blue dye and sodium chloride solution. Injection continues for 10 minutes. The pigment is used to trace the preferential flow.

[0037] S4: Data Acquisition. From the start of the rainfall system, all sensors and cameras are simultaneously activated. Runoff time, runoff flow rate, and infiltration flow rate are recorded, and runoff and infiltration samples are collected periodically. Simultaneously, the spatiotemporal dynamic distribution of moisture in the priority flow simulation system is monitored. Changes in soil moisture sensor readings are monitored throughout the process. Specifically, flow rate and velocity sensors deployed on the surface of the experimental soil 205 and at the runoff outlet 201 record the surface runoff time, runoff flow rate, and infiltration flow rate, and priority flow flowing from the bottom of the intermediate box 4 is collected through corresponding collection buckets 7. A turbidimeter installed in collection bucket 7 and an electronic balance at the bottom of collection bucket 7 collect runoff and infiltration samples to measure sediment content. The electronic balance can weigh in real time, and water samples collected in collection bucket 7 can be periodically removed during the collection process and their sediment content determined using a drying method. A soil moisture sensor array is used to monitor the spatiotemporal dynamic distribution of moisture in the priority flow simulation system. Simultaneously, a high-definition camera is used to record images of surface erosion and water flow within the fracture body 602.

[0038] S5: Post-processing and Analysis. After the experiment, the total sediment volume of the collected runoff, seepage, and preferential flow was first measured. Then, the experimental soil 205 in the intermediate box 4 was carefully removed layer by layer (the side walls of the intermediate box 4 can be made detachable for easy removal of the experimental soil 205). The distribution, morphology, and connectivity with the subsidence cracks of the preferential flow path indicated by the dye tracer were observed, photographed, and recorded. Finally, all data were synthesized to analyze the coupling effect among subsidence, rainfall, and preferential flow.

[0039] By changing variables such as subsidence, rainfall intensity, and the timing of preferential flow injection, and repeating the above experiment, the impact of various factors on soil erosion can be systematically studied.

[0040] Furthermore, the above operations allow for comparative studies by setting different experimental scenarios, including: rainfall without fissures, rainfall with closed fissures, and rainfall with open fissures and the application of fissure flow, to quantify the individual and coupled effects of fissures and their preferred flow on runoff, sediment yield, and water transport. It also allows for the simulation of soil erosion processes under different settlement intensities and multi-fissure network conditions by changing the position and number of fissure plates 6, or by selecting fissure plates 6 of different widths.

[0041] All of the above electrical equipment is controlled by a control module, that is, by a programmable PLC controller, and is available on the market unless otherwise stated.

[0042] 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 device for simulating soil and water loss in coal mining subsidence areas, characterized in that, Includes a support (1) and an experimental box (2). The experimental box (2) is installed on the support (1). The experimental box (2) contains an experimental soil (205). The experimental soil (205) contains a settlement crack simulation system. The top of the experimental box (2) is also equipped with a rainfall system. The subsidence fissure simulation system includes an intermediate box (4) set in the middle of the experimental box (2). The intermediate box (4) is buried in the experimental soil (205) of the experimental box (2). The intermediate box (4) is also set with experimental soil (205) and matched with one or more fissure plates (6). Each of the multiple fissure plates (6) is matched with a drive mechanism (5). The drive mechanism (5) can control the lifting and lowering of multiple fissure plates (6) and generate fissure bodies (602) in the corresponding experimental soil (205). The top of the intermediate box (4) is covered with a plastic film. Multiple fissure plates (6) penetrate the plastic film and are set inside the intermediate box (4). The rainfall system includes several water pipes (3) evenly arranged above the experimental chamber (2), and several full-cone nozzles evenly arranged on the water pipes (3). The water pipes (3) can carry water, and the full-cone nozzles can spray liquid water onto the top of the experimental chamber (2).

2. The soil and water loss simulation device for coal mining subsidence areas according to claim 1, characterized in that, It also includes a water collection system, which includes several collection buckets (7). The lower part of one side wall of the experimental box (2) is provided with a runoff outlet (201) and the bottom is provided with a seepage outlet (202). The runoff outlet (201) and the seepage outlet (202) are respectively connected to the two collection buckets (7) through water inlet pipes. The two collection buckets (7) are used to collect the surface runoff flowing out from the runoff outlet (201) and the underground seepage flowing out from the seepage outlet (202), respectively.

3. The soil and water loss simulation device for coal mining subsidence areas according to claim 2, characterized in that, The bottom of the intermediate box (4) is connected to a funnel (401), and the bottom of the funnel (401) is connected to a collection bucket (7) through a water pipe. The collection bucket (7) is used to collect the preferred flow from the bottom of the intermediate box (4). The bottom of the experimental box (2) is provided with a bottom slot for the water pipe to pass through.

4. The soil and water loss simulation device for coal mining subsidence areas according to claim 2, characterized in that, It also includes a data acquisition system, which includes: flow rate and velocity sensors installed on the surface of the experimental soil (205) and at the runoff outlet (201); soil moisture sensor array and pore water pressure sensor installed at different depths and horizontal positions on both sides of the fracture body (602); a high-definition camera device installed in front of the experimental box (2); a turbidity meter installed in the collection bucket (7) and an electronic balance at the bottom of the collection bucket (7); a laser rain spectrometer arranged on the surface of the experimental soil (205); and an ultrasonic detector for detecting the geometric dimensions of the fracture body (602).

5. A soil and water loss simulation device for coal mining subsidence areas according to claim 1, characterized in that, The experimental box (2) is made of high-strength steel. The front of the experimental box (2) is a transparent acrylic plate. The interior of the experimental box (2) is laid with a gravel drainage layer (203) and a geotextile filter layer (204) from bottom to top. The experimental soil (205) is placed above the geotextile filter layer (204). The experimental soil (205) is reconstituted soil filled in layers according to the original soil structure, or directly taken from the original soil of the coal mining subsidence area.

6. The soil and water loss simulation device for coal mining subsidence areas according to claim 1, characterized in that, The support (1) includes a base frame (101), a base frame (102) is provided on the top of the base frame (101), the bottom of the experimental box (2) is fixedly connected to the base frame (102), one end of the base frame (102) is rotatably connected to the base frame (101), one end of the base frame (101) is symmetrically fixed with an arc-shaped slide rail (103), the other end of the base frame (102) is slidably connected to the two arc-shaped slide rails (103) respectively through two sliders, a round hole is provided in the middle of the slider, and several notches are provided at equal intervals on both sides of the arc-shaped slide rail (103). The round hole can be inserted into the pin (104), and both ends of the pin (104) are provided with positioning rods (105). The two positioning rods (105) can be fitted into the two notches respectively. The pin (104) can position the base frame (102) and the arc-shaped slide rail (103). A hydraulic cylinder (106) for driving the base frame (102) to rotate is installed on the base frame (101).

7. The soil and water loss simulation device for coal mining subsidence areas according to claim 1, characterized in that, The water pipe (3) is detachably and fixedly mounted on the mounting frame, which can be placed on the ground by a support column, and the water pipe (3) can be connected to the water pump.

8. A soil and water loss simulation device for coal mining subsidence areas according to claim 1, characterized in that, The drive mechanism (5) includes a fixed frame (501), which is detachably fixed to the top of the experimental box (2). The bottom of the fixed frame (501) is provided with a waist-shaped hole (502). The middle part of the fixed frame (501) is provided with multiple electric telescopic rods (503). The telescopic rods (503) are controlled by telescopic rods (504). The telescopic rods (504) are vertically downward and telescopically connected to a connecting rod (505). The top of the rift plate (6) is provided with a threaded hole (601). The end of the connecting rod (505) can be threadedly connected to the threaded hole (601). The other end of the electric telescopic rod (503) can be fixedly connected to the waist-shaped hole (502) by bolts.

9. An experimental method using the apparatus according to any one of claims 1-8, characterized in that, Includes the following steps: S1: A gravel drainage layer (203) and a geotextile filter layer (204) are laid from top to bottom in the experimental box (2). Then, experimental soil (205) is filled in layers above the geotextile filter layer (204). The density and moisture content of the experimental soil (205) are controlled. When the filling reaches the design height, an intermediate box (4) is buried in the middle of the experimental box (2) in the experimental soil (205). The intermediate box (4) is buried in the experimental soil (205) of the experimental box (2). The intermediate box (4) is also equipped with the same number of layers of experimental soil (205) as the experimental soil (205) of the experimental box (2). A crack plate (6) is buried in the intermediate box (6). A drive mechanism (5) is matched in the crack plate (6). The top of the intermediate box (4) is covered with a plastic film. The crack plate (6) penetrates the plastic film and is set inside the intermediate box (4). S2: Then, the lifting and lowering of multiple fracture plates (6) is controlled by the drive mechanism (5), and a fracture body (602) with controllable position, depth and width is generated in the experimental soil (205) of the intermediate box (4). S3: Start the rainfall system to simulate rainfall by injecting pigment into the generated fracture body (602), the pigment is used to trace the preferential flow; S4: During the experiment, the surface runoff time, runoff and seepage process lines were recorded simultaneously, runoff and seepage samples were collected to measure sediment content, and the spatiotemporal dynamic distribution of water in the preferential flow simulation system was monitored. At the same time, images of surface erosion and water flow process in the fracture body (602) were recorded. S5: After the experiment, analyze all the collected data; then drain the water in the box, take out the experimental soil (205) in the middle box (4), observe and record the preferential flow path morphology shown by the tracer, the soil erosion characteristics of the wall of the fracture body (602), and the depth and range of lateral water infiltration.

10. The method according to claim 9, characterized in that, In step S2, the soil and water loss process under different settlement intensities and multi-fracture network conditions can be simulated by changing the position and number of the fracture plates (6) or by selecting fracture plates (6) of different widths.

Images