A test device and test method for dry filling coupled seepage similar simulation

Abstract

The application discloses a kind of dry filling coupling seepage similar simulation test device and test method, filling body is in the free falling state into observation box to simulate dry filling process;Seepage tank can be disassembled and installed in the upper end of observation box after filling filling body, grouting pump can be through grouting pipe to seepage tank to simulate mine roof seepage working condition, or after disassembling seepage tank, the liquid outlet end of grouting pump is through grouting pipe to the top or inside of filling body and injects filling slurry to simulate top grouting or internal grouting working condition;Pore water pressure sensor is buried in filling body to monitor seepage pressure change;Industrial camera is according to preset frequency and takes the wetting front advance image of filling body;Computer generates pressure, time curve and pressure, depth profile.The application solves the problem that dry filling scene and seepage scene coupling simulation demand in prior art is difficult to meet simultaneously, cannot realize dry filling top filling slurry and internal grouting reinforcement and other composite working condition simulation after filling.

Description

Technical Field

[0001] This invention relates to the field of mining backfilling and seepage testing technology, and more specifically to a test device and test method for dry backfilling coupled seepage similarity simulation. Background Technology

[0002] In the mining industry, backfilling mining is currently the mainstream development trend in underground mining. Compared with cemented backfilling, dry backfilling has the advantages of simple process and lower cost, and is widely used in small-scale mines or thin ore body mining.

[0003] Dry backfill is composed of loose granular materials such as waste rock and tailings, and has high permeability. In actual mining, when groundwater or roof fissure water seeps into the stope, it will infiltrate, migrate, and accumulate in the loosely piled dry backfill. If drainage is poor or the backfill has poor permeability, water can easily accumulate in the unconnected area above the stope. This water accumulation not only changes the stress state of the backfill, but more importantly, it will soak and soften adjacent primary pillars or existing cemented backfill over a long period, significantly weakening their mechanical properties (such as compressive and shear strength), potentially inducing local instability, debris flows, or even water inrush in the stope, seriously threatening the safety of underground operations. At the same time, dry backfill often has difficulty in roof connection and has weak bearing capacity. In order to improve the roof connection rate and the bearing capacity of the backfill, many mines use top grouting for roof connection and internal grouting pipes for later grouting reinforcement. The seepage of grout within the dry backfill will affect the roof connection and reinforcement effects.

[0004] Currently, simulation tests of groundwater seepage processes in soil and rock masses mostly focus on conventional soil and rock seepage tests, which cannot simultaneously meet the coupled simulation requirements of dry backfilling scenarios and seepage scenarios, let alone simulate composite working conditions such as cemented backfilling in areas not connected to the top after dry backfilling and grouting reinforcement inside the backfill body.

[0005] Therefore, how to provide a test device that can simulate both dry filling and seepage scenarios, and simultaneously has the functions of filling top grout and internal grouting, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides an experimental device and method for dry filling coupled with seepage similarity simulation, which solves the problem in the prior art that it is difficult to simultaneously meet the requirements of coupled simulation of dry filling scenario and seepage scenario, and that it is impossible to realize the simulation of composite working conditions such as filling top grout and internal grouting reinforcement after dry filling.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A test apparatus for dry-filling coupled seepage similarity simulation includes: An observation box with an open top surface allows the filling material to enter the observation box in a free-fall state to simulate the dry filling process. The seepage assembly includes a seepage tank and a grouting pump. The seepage tank is detachably installed on the upper end of the observation box after the filling material is filled into the observation box. The bottom wall of the seepage tank has multiple seepage holes that connect to the inner cavity of the observation box. The grouting pump is placed outside the observation box and can inject water into the seepage tank through the grouting pipe to simulate the seepage conditions of the mine roof. Alternatively, after the seepage tank is disassembled, the outlet end of the grouting pump can inject filling slurry into the top or interior of the filling material through the grouting pipe to simulate the conditions of roof grouting or internal grouting. A data acquisition component includes a pore water pressure sensor, an industrial camera, and a computer; the pore water pressure sensor is multiple and embedded in the filling body to monitor the seepage pressure changes within the filling body; the industrial camera captures images of the wetting front propagation of the filling body at a preset frequency; the computer is communicatively connected to the pore water pressure sensor and the industrial camera to generate pressure-time curves and pressure-depth profiles.

[0008] The beneficial effects of the technical solution of this invention are that this experimental device couples dry filling, seepage simulation, top grouting and internal grouting into one observation box. The combination of natural stacking dry filling method and pore water pressure sensor for multi-point seepage pressure monitoring allows the evolution law of seepage field inside the filler to be continuously and automatically recorded, overcoming the defect of inconsistent boundary conditions caused by refilling in traditional segmented tests. The multi-purpose design of one pump allows the same device to simulate dry filling process, top slab seepage, top grouting cementation filling and internal grouting reinforcement process, thus expanding the applicability of the device.

[0009] Preferably, the system further includes a drainage assembly, which comprises a drain pipe and a drain ball valve. A drain outlet is provided at the lower end of the side wall of the observation box, and a filter screen is fixed to the inner wall of the observation box corresponding to the drain outlet. One end of the drain pipe is fixedly connected to the drain outlet. The drain ball valve is installed on the drain pipe. The data acquisition assembly also includes a measuring cup and an electronic scale. The measuring cup is located at the other end of the drain pipe to collect the drainage. The electronic scale is used to weigh the measuring cup. The computer is connected to the electronic scale to generate water volume and time curves. After seepage is complete, the drain ball valve is opened to drain the water that has seeped into the filling body. Simultaneously, the drained water is collected in the measuring cup and weighed. The computer then generates water volume and time curves.

[0010] Preferably, a flow control valve is installed on the grouting pipe; the data acquisition component further includes a flow meter, which is installed on the grouting pipe and corresponds to the front end of the flow control valve in the liquid inlet direction; the computer is connected to the flow meter to plot the inlet flow rate and time curve. The flow control valve is opened according to the preset seepage velocity, and the inlet flow rate is monitored by the flow meter, and the inlet flow rate and time curve are generated by the computer.

[0011] Preferably, the data acquisition component further includes a multi-channel data acquisition instrument, which is electrically connected to the flow meter, the electronic scale and the pore water pressure sensor, and is communicatively connected to the computer.

[0012] Preferably, the system also includes a slag discharge assembly; the slag discharge assembly includes a flange pipe and a sealing disc; a slag discharge port is provided at the lower end of the side wall of the observation box; one end of the flange pipe is fixedly connected to the slag discharge port, and the inner diameter of the flange pipe is larger than the maximum particle size of the filling material; the sealing disc is detachably connected to the other end of the flange pipe. After the test is completed, by disassembling the sealing disc, the filling material carrying the pore water pressure sensor is discharged from the slag discharge port, and the pore water pressure sensor can be cleaned before the next simulation test.

[0013] Preferably, the observation box has multiple slots on its two opposing inner sidewalls; the bottom inner wall of the observation box has grooves that communicate with the slots; the two ends of the insert plate are inserted into the slots and the lower end is inserted into the groove, thus dividing the inner cavity of the observation box to adjust the test length. By selecting the insertion position of the insert plate in the observation box, the test length can be adjusted, and the insert plate can be prevented from lateral displacement during the test by the restriction of the slots and grooves.

[0014] Preferably, a sealing strip is embedded between the peripheral surface of the insert plate and the inner wall of the slot and the groove. The sealing strip provides a waterproof seal on the sides and bottom of the insert plate, ensuring the accuracy of the test results.

[0015] Preferably, the top of the observation box is fixed with multiple filling funnels, and the seepage channel is detachably installed below the discharge port of the filling funnels corresponding to the observation box. Filling material is introduced into the observation box using the filling funnels, ensuring that the filling material accumulates in a free-fall manner, thus simulating a dry filling process.

[0016] Preferably, multiple grout pipes are pre-embedded in the filling body, and the end of the grout pipe away from the grouting pump can be connected to multiple grout pipes. An internal grouting reinforcement simulation test is achieved using the multiple grout pipes pre-embedded in the filling body.

[0017] This invention also provides an experimental method for dry-fill coupled seepage similarity simulation, comprising: Seepage simulation: The filling material enters the observation box in a free-fall state. After the filling material reaches the target height, the seepage channel is installed. The inlet of the grouting pump is connected to a water source, and the outlet is injected with clean water into the seepage channel through the grouting pipe. The seepage channel continuously seeps water into the observation box through the seepage holes, eventually forming a water layer on the upper part of the observation box and corresponding to the surface of the filling material. The data acquisition component collects the water pressure and wetting front propagation images in the filling material in real time to complete the seepage simulation test. Simulation of top grouting or internal grouting: The filling material enters the observation box in a free-fall state. After the filling material is filled to the target height, the inlet end of the grouting pump is connected to the slurry tank, and the outlet end is injected into the surface or interior of the filling material through the grouting pipe. The penetration depth and range of the filling material slurry are observed to complete the simulation test of top grouting or internal grouting.

[0018] As can be seen from the above technical solution, compared with the prior art, this invention discloses a test device and test method for dry filling coupled seepage similarity simulation, integrating test length adjustment, natural accumulation filling, automatic image recognition, pore water pressure sensor recovery, and grouting functions into a single observation box. The cooperation between the insert plate and the slot not only realizes length adjustment, but also, in conjunction with the groove and sealing strip, ensures reliable sealing under variable length conditions; the combination of natural accumulation filling method and multi-point seepage pressure monitoring allows the evolution law of the seepage field inside the filling material under different length conditions to be continuously and automatically recorded, overcoming the defect of inconsistent boundary conditions caused by refilling in traditional segmented tests; the flange pipe design significantly improves the recovery rate of the pre-embedded pore water pressure sensor, reducing test costs; the multi-purpose design of the pump allows the same device to simulate both top seepage and top cemented filling and internal grouting reinforcement, expanding the applicability of the device and realizing continuous automatic monitoring of seepage and grouting processes under multiple working conditions in dry filling mines under variable length conditions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 A cross-sectional view of the seepage simulation of the experimental apparatus provided by the present invention; Figure 2 A simulated cross-sectional view of the test device for grouting provided by the present invention; Figure 3This is a simulated cross-sectional view of the grouting process inside the experimental device provided by the present invention. Figure 4 A side view of the test apparatus provided by the present invention; Figure 5 Top view of the test apparatus provided by the present invention; Figure 6 This is a partial schematic diagram of the insert plate installation provided by the present invention; Figure 7 This is a schematic diagram of the slag discharge assembly structure provided by the present invention; Figure 8 This is a schematic diagram of the seepage channel structure provided by the present invention; Figure 9 This is a schematic diagram of the drainage component structure provided by the present invention; Figure 10 A schematic diagram of the data acquisition component provided by the present invention.

[0021] Among them, 1-observation box; 11-slot; 12-insertion plate; 13-universal wheel; 2-filling funnel; 3-filling body; 4-seepage component; 41-grouting pump; 42-grouting pipe; 43-seepage channel; 44-slurry pipe; 45-flow control valve; 46-seepage hole; 5-data acquisition component; 51-flow meter; 52-electronic scale; 53-pore water pressure sensor; 54-industrial camera; 55-multi-channel data acquisition instrument; 56-computer; 57-measuring cup; 6-drainage component; 61-drainage pipe; 62-drainage ball valve; 63-filter screen; 7-slag discharge component; 71-flange pipe; 72-sealing plate; 8-water accumulation layer; 9-filling slurry. Detailed Implementation

[0022] 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.

[0023] The present invention aims to solve the problems in the prior art that it is difficult to simultaneously meet the coupled simulation requirements of dry filling scenario and seepage scenario, and cannot realize the simulation of composite working conditions such as filling the top grout and internal grouting reinforcement after dry filling. At the same time, it overcomes the defects such as the test length is not adjustable, the filling method deviates greatly from the field, the wet front identification depends on manual labor, the sensor recovery is difficult, and the cleaning efficiency is low. Example 1

[0024] See appendix Figure 1 Appendix Figure 4 - Appendix Figure 10This invention discloses an experimental device for dry filling coupled with seepage similarity simulation, used for seepage simulation experiments. It includes an observation box 1, a seepage component 4, and a data acquisition component 5. The top of the observation box 1 is open, and the side and bottom walls of the observation box 1 are made of transparent acrylic sheets, allowing optical transmission and direct observation of the interior of the observation box 1. The filling material 3 enters the observation box 1 in a free-fall state to simulate the dry filling process. The seepage component 4 includes a seepage channel 43 and a grouting pump 41. The seepage channel 43 is detachably installed on the upper end of the observation box 1 after the filling material 3 is filled in. The bottom wall of the seepage channel 43... Multiple seepage holes 46 are provided to connect to the inner cavity of the observation box 1; the grouting pump 41 is placed outside the observation box 1 and injects water into the seepage channel 43 through the grouting pipe 42 to simulate the seepage conditions of the mine roof; the data acquisition component 5 includes a pore water pressure sensor 53, an industrial camera 54 and a computer 56; the number of pore water pressure sensors 53 is multiple and they are buried in the filling body 3 to monitor the seepage pressure changes in the filling body 3; the industrial camera 54 takes images of the wet front propagation of the filling body 3 at a preset frequency; the computer 56 is connected to the pore water pressure sensor 53 and the industrial camera 54 to generate pressure-time curves and pressure-depth profiles.

[0025] In this embodiment, to facilitate the adjustment of the test length, multiple slots 11 are provided on the two inner sidewalls opposite to each other of the observation box 1; a groove corresponding to and communicating with the slots 11 is provided on the inner bottom wall of the observation box 1; the two ends of the insert plate 12 are inserted into the slots 11 and its lower end is inserted into the groove, thus dividing the inner cavity of the observation box 1 to adjust the test length.

[0026] like Figure 1 and Figure 6 As shown, the observation box adopts a cuboid box body. Multiple vertical slots are opened on the opposite side walls along its long axis. Multiple grooves are opened on the bottom wall, which are connected to the two slots arranged opposite to the two side walls. A handle is fixed to the upper end of the insertion plate. The two sides of the insertion plate are inserted into the two slots using the handle, and the bottom end of the insertion plate is inserted into the groove. The groove and slot limit the insertion plate. At the same time, the insertion plate can divide the inner cavity of the observation box. The insertion position of the insertion plate can be selected according to the preset test length, and the test length can be adjusted. Under the limitation of the slot and groove, the insertion plate will not undergo lateral displacement during the dry filling process.

[0027] To further optimize the above technical solution and prevent leakage on the periphery of the insert plate, a sealing strip 14 is embedded between the periphery of the insert plate 12 and the inner wall of the slot 11 and the groove.

[0028] To further optimize the above technical solution, the grouting pump is a small screw pump with an outlet pressure of 0.5-2MPa and an adjustable flow rate. It can deliver clean water to achieve constant pressure water supply, and it can also deliver cement slurry or tailings binder slurry to achieve grouting and filling.

[0029] In this embodiment, an energy dissipation elbow is provided at the end of the grouting pipe away from the grouting pump to prevent water from directly impacting the bottom of the seepage channel and causing local scouring.

[0030] To further optimize the above technical solution and ensure that the filling material falls naturally to simulate the natural accumulation filling process, multiple filling funnels 2 are fixed to the top of the observation box 1. A seepage channel 43 is detachably installed below the corresponding discharge port of the filling funnel 2 in the observation box 1. The multiple filling funnels 2 allow for uniform feeding along the length of the observation box 1, and the dry filling material formed by free fall more closely resembles the actual state of dry filling in the field, improving the similarity of the experiment.

[0031] In this embodiment, a drainage component 6 is also included, which includes a drainage pipe 61 and a drainage ball valve 62. A drainage port is provided at the lower end of the side wall of the observation box 1, and a filter screen 63 is fixed on the inner wall of the observation box 1 corresponding to the drainage port. One end of the drainage pipe 61 is fixedly connected to the drainage port. The drainage ball valve 62 is installed on the drainage pipe 61.

[0032] The drainage pipes are used for drainage after seepage is completed. In this embodiment, there are multiple drainage pipes distributed on the four side walls of the observation box to ensure complete drainage.

[0033] To further optimize the above technical solution, the data acquisition component 5 also includes a measuring cup 57 and an electronic scale 52; the measuring cup 57 is located at the other end of the drain pipe 61 to receive the drainage; the electronic scale 52 is used to support the weight of the measuring cup 57; the computer 56 is connected to the electronic scale 52 to generate water output and time curves.

[0034] In this embodiment, a flow control valve 45 is installed on the grouting pipe 42; the opening of the flow control valve 45 is adjusted according to the preset seepage rate.

[0035] To further optimize the above technical solution, the data acquisition component 5 also includes a flow meter 51, which is installed on the grouting pipe 42 and corresponds to the front end of the flow control valve 45 in the liquid inlet direction; the computer 56 is connected to the flow meter 51 for communication to plot the inlet flow rate and time curve. The flow control valve 45 adopts a high-precision needle valve, and the flow meter 51 adopts an electronic turbine flow meter or a rotor flow meter with an accuracy of not less than ±2%.

[0036] In this embodiment, to simulate seepage from the top slab, multiple seepage holes are evenly distributed along the bottom wall of the seepage channel. The seepage channel is made of 5mm thick transparent acrylic sheet, with multiple 2mm diameter seepage holes evenly distributed at the bottom. In practical applications, the inner wall of the top of the observation box has a stepped surface, and a limiting strip is bonded to the outer periphery of the seepage channel. The limiting strip can be engaged with the stepped surface to prevent displacement of the seepage channel during seepage.

[0037] To further optimize the above technical solution, the data acquisition component 5 also includes a multi-channel data acquisition instrument 55, which is electrically connected to a flow meter 51, an electronic scale 52 and a pore water pressure sensor 53, and is communicatively connected to a computer 56.

[0038] In this embodiment, a slag discharge assembly 7 is also included; the slag discharge assembly 7 includes a flange pipe 71 and a sealing disc 72; a slag discharge port is provided at the lower end of the side wall of the observation box 1; one end of the flange pipe 71 is fixedly connected to the slag discharge port, and the inner diameter of the flange pipe 71 is larger than the maximum particle size of the filling material 3; the sealing disc 72 is detachably connected to the other end of the flange pipe 71. Figure 4 As shown, the sealing disc 72 is fastened to the flange pipe 71 by bolts, and a sealing gasket is provided between the end faces of the sealing disc 72 and the flange pipe 71 to ensure sealing performance and prevent leakage.

[0039] To further optimize the above technical solution, the bottom of the observation box 1 is rotatably connected with multiple casters 13 with braking function, which facilitates the movement of the observation box 1.

[0040] To further optimize the above technical solution, the observation box 1 includes a main frame and an observation plate. The main frame is welded from square tubes, and the observation plate is a transparent acrylic plate. The observation plate is fixed to the inside and bottom of the main frame, and the two adjacent observation plates are sealed with sealant.

[0041] The seepage simulation test is conducted using a test apparatus for dry-filling coupled seepage similarity simulation according to this embodiment, including the following steps: A1. Fill the filling funnel 2 with filling material 3, which is made of loose materials such as waste rock or tailings. Fill material 3 enters the observation box 1 in a free-fall state through the filling funnel 3. During the filling process, pore water pressure sensors 53 are arranged in three rows along the longitudinal direction inside the filling material 3, with a row spacing of 150mm to 200mm. Each row is equipped with 3 to 4 sensors in the vertical direction, and the layer spacing between each sensor is 150mm to 250mm. The pore water pressure sensors 53 are arranged according to the filling height. The segmented filling method is adopted. After filling to the target height, the filling is stopped and the pore water pressure sensors 53 are installed with their pressure sensing surfaces facing upwards. They are led upwards through the lead wires and connected to the multi-channel data acquisition instrument 55. A2. After the filling body 3 is filled to the target height, install the seepage channel 43; A3. The inlet end of the grouting pump 41 is connected to a water source, and the outlet end injects clean water into the seepage tank 43 through the grouting pipe 42. During the water injection process, the opening of the flow control valve 45 is adjusted according to the seepage speed. The clean water injected into the seepage tank 43 continuously seeps into the observation box 1 through multiple evenly arranged seepage holes 46, and finally a water accumulation layer 8 is generated on the upper end of the observation box 1 and the surface of the corresponding filling body 3. A4. An industrial camera 54 captures images of the front of the observation box 1 at a frequency of 1 frame / minute to obtain images of the advancing wet front. A pore water pressure sensor 53 has a range of 0-10 kPa, an accuracy of ±0.1%FS, a diameter of ≤15 mm, and an IP68 protection rating. A miniature pore water pressure sensor 35 monitors the seepage pressure changes at each measuring point in real time, and the signals are acquired and stored by a multi-channel data acquisition instrument 55. A flow meter 51 monitors the instantaneous flow rate and cumulative inflow in real time, and an electronic scale 52 weighs the seepage in real time. All data are collected uniformly at a sampling frequency of 1 Hz and stored in the computer with a unified timestamp. The inflow-time curve, pressure-time curve, and pressure-depth profile of each measuring point are plotted in real time. A5. After the seepage is completed, open the drain ball valve 62 to drain the water inside the observation box 1, collect the water through the measuring cup 57, weigh it with the electronic scale 52, and then feed the data back to the computer 56 to generate the water output-time curve. A6. After the test, loosen the fastening bolts, remove the sealing cap 72, and the filling body 3 will be automatically discharged from the slag discharge port under the action of gravity; pick out the pore water pressure sensor 53 from the discharged material, clean and dry it for later use; use tools such as high-pressure water gun to clean the inside of the observation box 1 and check the sealing performance before proceeding to the next test. Example 2

[0042] This invention discloses a test apparatus for dry filling coupled seepage similarity simulation, used for grouting simulation tests. Unlike Embodiment 1, this embodiment does not use a seepage tank; the rest of the structure is the same. The grouting simulation test includes the following steps: B1. Add filling material 3 into filling funnel 2. Filling material 3 is made of loose materials such as waste rock or tailings. Filling material 3 enters observation box 1 in a free-fall state through filling funnel 3. After filling is completed, the height of filling material 3 is lower than the top of observation box 1 to reserve a top contact area. B2. After filling is completed, when preparing the filling slurry 9, add red dye (such as red ink or special tracer dye) at 0.5‰ to 1‰ of the slurry volume, stir thoroughly and evenly, so that the solidified cementitious body forms a clear color difference with the surrounding loose filling material; turn on the grouting pump 41, and inject the filling slurry 9 into the unconnected area at the top of the observation box 1 through the grouting pipe 42; continue grouting until the unconnected area is completely filled with the filling slurry 9. B3. Observe and record the flow and filling process of the filling grout 9 in the unconnected area, as well as the penetration depth and range of the filling grout 9 into the dry backfill 3 below before solidification; after static curing until the filling grout 9 solidifies, observe the bonding between the cemented backfill and the dry backfill below. B4. After the test, open the drain ball valve 62 to drain the excess filling slurry 9 (if any); loosen the fastening bolts, remove the sealing cap 72, and the filling body 3 will be automatically discharged from the slag discharge port under gravity; pick out the pore water pressure sensor 53 from the discharged material, clean and dry it for later use; use tools such as a high-pressure water gun to clean the inside of the observation box 1 and check the sealing performance before proceeding to the next test. Example 3

[0043] This invention discloses a test device for dry filling coupled seepage similarity simulation, used for internal grouting reinforcement simulation test. Unlike embodiment 1, this embodiment does not use a seepage tank, but the rest of the structure is the same. It also includes grout pipes 44. Multiple grout pipes 44 are pre-embedded in the filling body 3. The end of the grouting pipe 42 away from the grouting pump 41 can be connected to multiple grout pipes 44. Multiple grout outlet holes are opened on the closed part of the multiple grout pipes 44.

[0044] The following steps are included in the simulation test of internal grouting reinforcement: C1. Add filling material 3 into filling funnel 2. Filling material 3 is made of loose materials such as waste rock or tailings. Filling material 3 enters observation box 1 through filling funnel 3 in a free-falling state. C2. After filling is completed, when preparing the filling slurry 9, add red dye (such as red ink or special tracer dye) at 0.5‰ to 1‰ of the slurry volume and stir thoroughly; turn on the grouting pump 41, adjust the flow control valve 45 to the preset grouting pressure, and send the filling slurry 9 through the grouting pipe 42. The filling slurry 9 permeates and diffuses into the surrounding filling body 3 from the slurry outlet hole on the pipe wall of the grouting pipe 44. C3. Observe and record the process of the filling slurry 9 permeating and diffusing from the slurry outlet into the surrounding filling body 3, as well as the effects of different grouting pressures and different slurry ratios on the diffusion radius and cementation range; C4. After grouting is completed, turn off grouting pump 41, let it stand for curing, and observe the formation of cementitious material. C5. After the test, open the drain ball valve 62 to drain the excess filling slurry 9 (if any); loosen the fastening bolts, remove the sealing cap 72, and the filling body 3 will be automatically discharged from the slag discharge port under gravity; pick out the pore water pressure sensor 53 from the discharged material, clean and dry it for later use; use high-pressure water gun and other tools to clean the inside of the observation box 1 and check the sealing performance before proceeding to the next test. Example 4

[0045] Unlike Examples 1-3, in this example, different insertion positions of the insert plate 12 can be selected according to experimental needs to simulate the influence of different filling step distances or stope lengths on the seepage process. When simulating a shorter filling length, the insert plate 12 is inserted into the vertical slot 11 closer to the slag discharge port; when simulating a longer filling length, the insert plate 12 is inserted into the slot 11 farther from the slag discharge port. By adjusting the experimental length, the relationship between stope length and seepage characteristics can be systematically studied. Example 5

[0046] Unlike Example 1, this example allows for variation in the thickness of the backfill material 3 to simulate the impact of different stope backfill heights on the seepage process. Specifically, by controlling the amount of material fed into the backfill funnel 2, three sets of tests were conducted with backfill thicknesses of 500mm, 800mm, and 1000mm. Under the same seepage conditions, the differences in wetting front penetration time, pore water pressure distribution along depth, and bottom drainage volume under different backfill thicknesses were compared and analyzed. By changing the backfill thickness, the relationship between stope backfill height and seepage response can be systematically studied. Example 6

[0047] Unlike Example 1, in this example, a dye can be incorporated into the filling body 3 to improve the color contrast between the wet and dry areas, thereby enhancing the recognition accuracy of images captured by the industrial camera. After the images are transmitted to the computer, a custom program developed based on Python + OpenCV is used to automatically identify the position of the leading edge of the wet front and record its coordinates through grayscale binarization and edge detection algorithms.

[0048] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0049] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test apparatus for dry-filling coupled seepage similarity simulation, characterized in that, include: The observation box (1) has an open top surface, and the filling material (3) enters the observation box (1) in a free-fall state to simulate the dry filling process; The seepage assembly (4) includes a seepage tank (43) and a grouting pump (41). The seepage tank (43) is detachably installed on the upper end of the observation box (1) after the filling body (3) is filled into the observation box (1). The bottom wall of the seepage tank (43) is provided with multiple seepage holes (46) that connect to the inner cavity of the observation box (1). The grouting pump (41) is placed outside the observation box (1) and can inject water into the seepage tank (43) through the grouting pipe (42) to simulate the seepage condition of the mine roof. Alternatively, after the seepage tank (43) is disassembled, the liquid outlet of the grouting pump (41) injects filling slurry (9) into the top or inside of the filling body (3) through the grouting pipe (42) to simulate the top grouting or internal grouting condition. The data acquisition component (5) includes a pore water pressure sensor (53), an industrial camera (54), and a computer (56). The pore water pressure sensor (53) is multiple and is embedded in the filling body (3) to monitor the seepage pressure changes in the filling body (3). The industrial camera (54) captures images of the wet front propagation of the filling body (3) at a preset frequency. The computer (56) is communicatively connected to the pore water pressure sensor (53) and the industrial camera (54) to generate pressure-time curves and pressure-depth profiles.

2. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 1, characterized in that, It also includes a drainage assembly (6), which includes a drain pipe (61) and a drain ball valve (62); a drain outlet is provided at the lower end of the side wall of the observation box (1), and a filter screen (63) is fixed on the inner wall of the observation box (1) corresponding to the drain outlet; one end of the drain pipe (61) is fixedly connected to the drain outlet; the drain ball valve (62) is installed on the drain pipe (61); The data acquisition component (5) also includes a measuring cup (57) and an electronic scale (52); the measuring cup (57) is located at the other end of the drain pipe (61) to receive the drainage; the electronic scale (52) is used to support the weight of the measuring cup (57); the computer (56) is connected to the electronic scale (52) to generate the water output and time curve.

3. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 2, characterized in that, A flow control valve (45) is installed on the grouting pipe (42); the data acquisition component (5) also includes a flow meter (51), which is installed on the grouting pipe (42) and corresponds to the front end of the flow control valve (45) in the liquid inlet direction; the computer (56) is connected to the flow meter (51) to plot the water inlet and time curves.

4. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 3, characterized in that, The data acquisition component (5) also includes a multi-channel data acquisition instrument (55), which is electrically connected to the flow meter (51), the electronic scale (52) and the pore water pressure sensor (53), and is communicatively connected to the computer (56).

5. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 1, characterized in that, It also includes a slag discharge assembly (7); the slag discharge assembly (7) includes a flange pipe (71) and a sealing disc (72); a slag discharge port is provided at the lower end of the side wall of the observation box (1); one end of the flange pipe (71) is fixedly connected to the slag discharge port, and the inner diameter of the flange pipe (71) is larger than the maximum particle size of the filling body (3); the sealing disc (72) is detachably connected to the other end of the flange pipe (71).

6. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 1, characterized in that, Multiple slots (11) are provided on the two inner sidewalls opposite to each other of the observation box (1); a groove corresponding to and communicating with the slots (11) is provided on the inner bottom wall of the observation box (1); the two ends of the insert plate (12) are inserted into the slots (11) and its lower end is inserted into the groove, and the inner cavity of the observation box (1) is divided to adjust the test length.

7. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 6, characterized in that, A sealing strip (14) is embedded between the circumferential surface of the insert plate (12) and the inner wall of the slot (11) and the groove.

8. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 7, characterized in that, The top of the observation box (1) is fixed with multiple filling funnels (2), and the seepage channel (43) is detachably installed below the discharge port of the filling funnel (2) of the observation box (1).

9. The experimental apparatus for dry-filling coupled seepage similarity simulation according to claim 1, characterized in that, Multiple grout pipes (44) are pre-embedded in the filling body (3), and the end of the grouting pipe (42) away from the grouting pump (41) can be connected to multiple grout pipes (44).

10. A test method for dry-fill coupled seepage similarity simulation, characterized in that, The experimental apparatus for dry-filling coupled seepage similarity simulation according to any one of claims 1 to 9 comprises: Seepage simulation: The filling body (3) enters the observation box (1) in a free-fall state. After the filling body (3) is filled to the target height, the seepage trough (43) is installed. The inlet end of the grouting pump (41) is connected to a water source, and the outlet end injects clean water into the seepage trough (43) through the grouting pipe (42). The seepage trough (43) continuously seeps water into the observation box (1) through the seepage hole (46), and finally a water accumulation layer (8) is generated on the upper end of the observation box (1) and the surface corresponding to the filling body (3). The data acquisition component (5) collects the water pressure and wetting front propagation image in the filling body (3) in real time to complete the seepage simulation test. Top grouting or internal grouting simulation: The filling body (3) enters the observation box (1) in a free fall state. When the filling body (3) is filled to the target height, the inlet end of the grouting pump (41) is connected to the slurry tank, and the outlet end is injected into the surface or interior of the filling body (3) through the grouting pipe (42). The penetration depth and range of the filling slurry (9) are observed to complete the top grouting or internal grouting simulation test.

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