A leaching test device for filling paste

Abstract

This invention relates to the field of leaching test technology for filling pastes, and discloses a leaching test device for filling pastes. The double-layer nested water distribution component has a built-in gridded flow guide skeleton, which is embedded inside the filling paste. Water flow guiding components corresponding to the gridded flow guide skeleton are uniformly connected and installed on the inner wall of the double-layer nested water distribution component. The double-layer nested water distribution component realizes the homogenization of water pressure and flow rate, the water flow guiding components realize the graded flow velocity control of water flow, the microporous transition flow guide medium realizes interference-free infiltration, and the gridded flow guide skeleton realizes the uniform distribution of water flow throughout the entire area, ensuring that the water flow flows evenly and stably along the preset path. Ultimately, it realizes the full-area, undisturbed, and uniform infiltration guidance of the filling paste, providing accurate and stable water flow conditions for the filling paste shower experiment, and ensuring the authenticity and repeatability of experimental data.

Description

Technical Field

[0001] This invention relates to the field of leaching test technology for filling pastes, and particularly to a leaching test device for filling pastes. Background Technology

[0002] In recent years, the problem of coal mining under the "three-down-up" principle has become increasingly prominent in my country. my country's backfilling mining technology has also become more and more advanced. However, the impact of the backfill material on the groundwater environment after it enters the ground has not attracted much attention from scholars. Most of the current research focuses on the leaching experiments of coal gangue and fly ash.

[0003] In the indoor simulation leaching system for coal gangue, fly ash, and filling paste, application number CN201820579125.8, the leaching device includes an soaking unit and a collection unit. The soaking unit includes a box and a cylindrical tank located inside the box. The cylindrical tank is hollow inside and has water-permeable holes on its walls. The top of the box is connected to a water pipe, and a nozzle is connected to the water pipe at the top of the box. The nozzle fits snugly onto the cylindrical tank. An annular filter screen is installed inside the cylindrical tank to simulate the leaching process of coal gangue and fly ash with different ratios.

[0004] However, in actual use, most existing shower tests of filling pastes adopt natural water spraying without a dedicated water flow guidance system. Due to the high viscosity, high density, and low porosity of the filling paste itself, and the heterogeneity of the paste accumulation, problems such as uneven water flow distribution, local crossflow, surface water accumulation, or dry stains occur during the water spraying process. This distorts the experimental conditions and makes it impossible to achieve uniform water penetration throughout the paste. The measured penetration data can only reflect the penetration characteristics of local areas and cannot represent the overall penetration capacity of the paste. The accuracy and repeatability of the experimental data are poor.

[0005] Therefore, the present invention proposes a leaching test device for filling pastes to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a leaching test device for filling pastes to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a leaching test device for filling paste, comprising a double-layer nested water distribution assembly, wherein a sealing cover is fitted on the top of the double-layer nested water distribution assembly, the double-layer nested water distribution assembly has a built-in gridded flow guide skeleton, and the gridded flow guide skeleton is embedded inside the filling paste, and water flow guiding components corresponding to the gridded flow guide skeleton are uniformly connected and installed on the inner sidewall of the double-layer nested water distribution assembly; The water flow guiding component is obliquely and slightly tangentially arranged and not perpendicular to the surface of the filling paste. It includes a surface wide water distribution section, the bottom of which is connected to a middle flow limiting and stabilizing section. The bottom of the middle flow limiting and stabilizing section is connected to a bottom micro-permeation and slow-release section. A microporous transition flow guiding medium layer is provided between the bottom end of the bottom micro-permeation and slow-release section and the surface of the filling paste. The contact surfaces of the microporous transition flow guiding medium layer with the bottom end of the bottom micro-permeation and slow-release section and the filling paste are coated with a waterproof sealing layer. The pore size of the microporous transition flow guiding medium layer is smaller than the minimum particle size of the filling paste particles.

[0008] Preferably, the double-layer nested water distribution assembly includes an outer water distribution frame, an inner guide frame is fixedly sleeved at the bottom of the outer water distribution frame, a pressure equalization cavity is set between the outer water distribution frame and the inner guide frame, and a pressure equalization plate is uniformly fixedly arranged from bottom to top in the pressure equalization cavity, and pressure equalization holes are uniformly opened on the pressure equalization plate.

[0009] Preferably, an inlet pipe is fixedly installed at the bottom of the outer side wall of the outer water distribution frame, and the inlet pipe is connected to the pressure equalization chamber. The outer end of the inlet pipe is connected to a constant flow pump, and a flow regulating valve is installed on the inlet pipe.

[0010] Preferably, the inner guide frame has longitudinally arranged guide grooves evenly distributed inside, and the water flow guiding component also includes a connector that communicates with the guide grooves, and the connector is fixedly connected to the top of the surface wide water distribution part.

[0011] Preferably, the sealing cover is sealed on the top of the outer water distribution frame, and a sealing ring is encapsulated between the sealing cover and the double-layer nested water distribution assembly. An inner pressure plate is fixedly installed inside the sealing cover and sealed on the top of the inner guide frame. A guide port communicating with the pressure equalization chamber is provided between the inner pressure plate and the sealing cover. Vent holes are provided at the four corners of the top of the sealing cover.

[0012] Preferably, the gridded flow guide frame is a three-dimensional grid frame composed of several sets of microtube bundle nodes and flexible micro-flow guide wires. It is embedded inside the filling paste to divide the filling paste into several sets of micro-units with the same space without damaging the main structure of the filling paste. The top of the gridded flow guide frame is provided with a water inlet pipe corresponding to the micro-unit, and the bottom of the gridded flow guide frame is provided with a drainage pipe corresponding to each set of water inlet pipes. The drainage pipe extends out to the bottom of the double-layer nested water distribution component.

[0013] Preferably, the internal pressure plate has a drainage port that corresponds one-to-one with the water inlet pipe. The water inlet pipe is embedded in the drainage port and is connected to the guide channel through a branch pipe, which is used to guide the water to the water flow guiding component. The water flow guiding component corresponds to the micro unit.

[0014] Preferably, the diameter of the guiding channel inside the surface wide water distribution section is 2-5mm, the diameter of the guiding channel inside the middle flow limiting and stabilizing section is 1-2mm, the diameter of the guiding channel inside the bottom micro-permeation and slow-release section is 0.5-1mm, and the angle between the oblique micro-tangential direction of the guiding channel and the surface of the filling paste is 15-30°.

[0015] Preferably, the water collection assembly includes a fixing frame fixed on the outer wall of the outer water distribution frame, a water collection tank corresponding to the drainage pipe is fixedly installed on the fixing frame, and a drainage pipe is installed at the bottom of the water collection tank.

[0016] The technical effects and advantages of this invention are as follows: This invention achieves a complete flow path for water pre-pressurization and wetting, multi-stage pressure equalization, gradient flow guidance, and undisturbed infiltration through the synergistic effect of a double-layer nested water distribution component, a gridded flow guiding frame, and a water flow guiding component. The double-layer nested water distribution component equalizes water pressure and flow rate, the water flow guiding component enables graded flow velocity control, the microporous transition flow guiding medium enables undisturbed infiltration, and the gridded flow guiding frame ensures uniform distribution of water flow throughout the entire area. This ensures that the water flows evenly and stably along the preset path, ultimately achieving undisturbed and uniform infiltration guidance of the filling paste throughout the entire area. This provides precise and stable water flow conditions for the filling paste shower experiment, ensuring the authenticity and repeatability of the experimental data. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic cross-sectional view of the overall structure of the present invention; Figure 3 This is a schematic diagram of the overall exploded structure of the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram of section A in the middle; Figure 5 For the present invention Figure 3 Enlarged structural diagram of section B in the middle; Figure 6 This is a schematic diagram of the sealing cover structure of the present invention; Figure 7 This is a schematic diagram of the first-view structure of the gridded flow guide skeleton of the present invention; Figure 8 This is a schematic diagram of the second-view structure of the gridded flow guide skeleton of the present invention; Figure 9 This is a schematic diagram of the water flow guiding component of the present invention.

[0018] In the diagram: 10. Double-layer nested water distribution assembly; 11. Outer water distribution frame; 12. Inner guide frame; 13. Pressure equalization chamber; 14. Pressure equalization plate; 15. Pressure equalization hole; 16. Guide channel; 17. Inlet pipe; 20. Mesh guide skeleton; 21. Microtube bundle node; 22. Flexible micro-guide wire; 23. Micro-unit; 24. Inlet water diversion pipe; 25. Drainage diversion pipe; 30. Sealing cover plate; 31. Inner pressure plate; 32. Guide port; 33. Drainage port; 40. Water flow guiding assembly; 41. Connector; 42. Surface wide water distribution section; 43. Middle layer flow limiting and stabilizing section; 44. Bottom layer micro-permeation slow release section; 45. Microporous transition guide medium layer; 50. Water collection assembly; 51. Fixing frame; 52. Water collection pool; 53. Drainage pipe. Detailed Implementation

[0019] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] To address the aforementioned issues, some experimental schemes have attempted to incorporate microchannels, baffles, and other flow-guiding structures within the filling paste to guide water flow uniformly throughout the paste. However, such flow-guiding structures have significant design flaws: Firstly, the flow-guiding structure is in direct contact with the filling paste, easily creating artificial strong channels that alter the paste's own permeation path and resistance. This leads to a conflict between the flow-guiding structure and the paste's permeability testing, making the measured permeability data unable to reflect the paste's true inherent characteristics. Secondly, existing flow-guiding structures are mostly fixed, which can easily generate excessively high local water pressure during water flow guidance, causing hydraulic fracturing of the paste and damaging its original structure, further affecting the accuracy of the experimental results. Based on this, this embodiment proposes the following optimization scheme: like Figures 1 to 9As shown, this embodiment discloses a leaching test device for filling paste, including a double-layer nested water distribution assembly 10. A sealing cover 30 is fitted to the top of the double-layer nested water distribution assembly 10. A gridded flow guide frame 20 is built into the double-layer nested water distribution assembly 10 and embedded inside the filling paste. Water flow guide components 40, corresponding to the gridded flow guide frame 20, are uniformly connected and installed on the inner wall of the double-layer nested water distribution assembly 10. The water flow guide components 40 are inclined towards... The structure is tangentially oriented and not perpendicular to the surface of the filling paste. It includes a surface wide water distribution section 42, a middle flow-limiting and stabilizing section 43 connected to the bottom of the surface wide water distribution section 42, a bottom micro-permeability and slow-release section 44 connected to the bottom of the middle flow-limiting and stabilizing section 43, and a microporous transition flow guiding medium layer 45 disposed between the bottom end of the bottom micro-permeability and slow-release section 44 and the surface of the filling paste. A waterproof sealing layer is applied to the contact surfaces of the microporous transition flow guiding medium layer 45 with the bottom end of the bottom micro-permeability and slow-release section 44 and the filling paste. Furthermore, the pore size of the microporous transition flow guiding medium layer 45 is smaller than the minimum particle size of the filling paste particles. The water flow guiding component 40 has a gradient flow guiding structure to avoid hydraulic splitting caused by high-pressure direct impact. The flexible flow guiding skeleton adapts to the slight deformation of the paste, ensuring that the paste maintains its original structure during the experiment. The test target focuses on the water resistance stability and permeability characteristics of the paste itself, avoiding the distortion of test results caused by improper experimental conditions. The water flow guiding component 40 and the gridded flow guiding skeleton 20 are only responsible for uniformly delivering water to the surface and interior of the filling paste, while the microporous transition flow guiding medium layer 45 is in direct contact with the filling paste, without forming artificial strong channels, and without changing the pore structure, permeation path and permeation resistance of the paste itself. The flow guiding medium ensures that the permeation process after the water enters the paste is completely determined by the physical properties of the paste itself, ensuring that the measured permeation data can truly reflect the inherent permeability of the paste, without any conflict with the permeation test, and has a significant synergistic effect.

[0021] In actual use, the double-layer nested water distribution component 10 allows for pre-pressurized water storage, which can achieve initial homogenization of water flow pressure, completely eliminate pressure fluctuations at the water inlet, and ensure stable water flow pressure flowing into the gridded guide frame 20 and water flow guiding component 40. During the slow flow of water, the air inside the guide network such as the double-layer nested water distribution component 10 and the gridded guide frame 20, as well as the air on the surface of the paste sample, is squeezed by the water flow and gradually flows upward, eventually being discharged through the vent hole at the top of the sealing cover plate 30. This process continues until no air bubbles are discharged from the vent hole, indicating that the entire guide network has been filled with unpressurized water, completely eliminating the problems of water flow impact, air blockage, and local scouring caused by "sudden water ingress into the dry channel".

[0022] Please see Figures 2-5The double-layer nested water distribution assembly 10 includes an outer water distribution frame 11, an inner guide frame 12 fixedly fitted inside the bottom of the outer water distribution frame 11, and micro-sized mesh drainage channels evenly distributed on the outer side wall of the inner guide frame 12. A pressure equalization chamber 13 is set between the outer water distribution frame 11 and the inner guide frame 12. Pressure equalization plates 14 are evenly fixedly arranged from bottom to top in the pressure equalization chamber 13. Pressure equalization holes 15 are evenly opened on the pressure equalization plates 14. A water inlet pipe 17 is fixedly installed at the bottom of the outer side wall of the outer water distribution frame 11, and the water inlet pipe 17 is connected to the pressure equalization chamber 13. The outer end of the inlet pipe 17 is connected to the constant flow pump, and a flow regulating valve is installed on the inlet pipe 17. When the constant flow pump is working, it can pump water into the pressure equalization chamber 13 through the inlet pipe 17. The flow regulating valve is used to adjust the water flow rate in the pre-pressurization stage. The water flow rate in the pre-pressurization stage is 1 / 5 of the actual water flow rate in the experiment. The pressure equalization plate 14 and the pressure equalization hole 15 are used to achieve a uniform distribution of water flow pressure in the pressure equalization chamber 13, eliminate water flow pressure fluctuations, and ensure that the water flow pressure entering the water flow guide component 40 is stable and the flow rate is uniform.

[0023] Please see Figure 3 and Figure 5 The inner guide frame 12 is provided with longitudinally arranged guide grooves 16 evenly distributed. The water flow guiding component 40 also includes a connector 41 that communicates with the guide grooves 16. The connector 41 is fixedly connected to the top of the surface wide water distribution part 42, so as to ensure that the water inside the guide grooves 16 can flow into the water flow guiding component 40 through the connector 41, thereby realizing the secondary diversion of water flow, improving the uniformity of water distribution, and ensuring that the water input of each water inlet node is consistent.

[0024] Please see Figures 1-3 and Figure 6 The sealing cover 30 covers the top of the outer water distribution frame 11, and a sealing ring is sealed between the sealing cover 30 and the double-layer nested water distribution assembly 10. An inner pressure plate 31 is fixedly installed inside the sealing cover 30 and covers the top of the inner guide frame 12. A guide port 32 communicating with the pressure equalization chamber 13 is provided between the inner pressure plate 31 and the sealing cover 30. Vent holes are opened at the four corners of the top of the sealing cover 30. After the sealing cover 30 covers the top of the double-layer nested water distribution assembly 10, the water inside the pressure equalization chamber 13 can flow from the bottom to the top of the guide port 32 and into the inner pressure plate 31, which facilitates the flow of water. The pre-pressurized uniform water inlet can eliminate water flow impact and air blockage.

[0025] Please see Figure 2 , Figure 7 and Figure 8The gridded flow guide frame 20 is a three-dimensional grid framework composed of several sets of microtube bundle nodes 21 and flexible micro-flow guide wires 22. It is embedded inside the filling paste and divides the filling paste into several sets of micro-units 23 with the same space without destroying the structure of the filling paste body. The top of the gridded flow guide frame 20 is provided with water inlet pipes 24 corresponding to the micro-units 23, and the bottom of the gridded flow guide frame 20 is provided with drainage pipes 25 corresponding to each set of water inlet pipes 24. The drainage pipes 25 extend to the bottom of the double-layer nested water distribution component 10, dividing the filling paste into uniform micro-units 23, realizing uniform and dead-angle-free water flow guidance to the entire area of ​​the paste, completely eliminating problems such as local crossflow, water accumulation, and dry stains caused by natural water spray, and ensuring the uniformity and standardization of experimental conditions.

[0026] The internal pressure plate 31 has a corresponding inlet 33 for each of the inlet pipes 24. The inlet pipes 24 are embedded in the inlet 33 and are connected to the guide channel 16 via branch pipes. This guide channel 16 is used to guide water to the water flow guiding component 40. The water flow guiding component 40 corresponds to the micro-unit 23. In actual use, the water inside the equalizing chamber 13 flows naturally into the inlet pipes 24 through the inlet 33. At this time, the water flow is divided into two paths for coordinated infiltration. One part of the water flow flows along the gaps of the flexible micro-guide wires 22 of the gridded guide frame 20, wetting the entire grid structure. Due to the gridded guide frame 20... The 0 is embedded inside the filling paste. Water can slowly penetrate into the surrounding spatial micro-units 23 through the grid gaps. Another part of the water flows into the water flow guiding component 40 through the branch pipe and the guide groove 16 on the inner guide frame 12. After being gradient controlled by the water flow guiding component 40, it passes through the microporous transition guide medium layer 45. Its pores are smaller than the paste particles, allowing only water to pass through. In this way, the water can directly penetrate into the surface of the filling paste. The two types of water flow converge in the spatial micro-units 23 and slowly penetrate along the pores of the paste itself. Finally, it flows out through the drainage pipe 25 at the bottom of the gridded guide frame 20, achieving full-area penetration without dead corners.

[0027] Please see Figure 9The guide channel inside the surface wide water distribution section 42 has a diameter of 2mm, the guide channel inside the middle flow limiting and stabilizing section 43 has a diameter of 1mm, and the guide channel inside the bottom micro-permeation and slow-release section 44 has a diameter of 0.5mm. The angle between the oblique micro-tangential direction of the guide channel and the surface of the filling paste is 20°, which can avoid the water flow from vertically rushing into the paste and causing hydraulic splitting. At the same time, when the water flow passes through the surface wide water distribution section 42, the middle flow limiting and stabilizing section 43 and the bottom micro-permeation and slow-release section 44 in sequence, the water flow can be released in stages to adapt to the different depths of the paste's penetration characteristics. This ensures that the water flow slowly and evenly approaches the paste surface, laying the foundation for undisturbed penetration. The water flow guiding component 40 can not only ensure the rapid and uniform distribution of the surface water flow, but also achieve the stabilization and flow limiting of the middle water flow to avoid crossflow, while ensuring that the bottom water flow can slowly penetrate, truly reflecting the deep penetration characteristics of the paste.

[0028] Please see Figure 1 and Figure 3 The water collection component 50 includes a fixing frame 51 fixed on the outer wall of the outer water distribution frame 11. A water collection tank 52 corresponding to the drainage pipe 25 is fixedly installed on the fixing frame 51, and a drain pipe 53 is installed at the bottom of the water collection tank 52. Water flowing out from the drainage pipe 25 can fall directly into the water collection tank 52 for collection, and finally be discharged through the drain pipe 53 for easy recycling.

[0029] In summary, this embodiment went through two stages: pre-pressure impregnation and trial operation, specifically as follows: I. Pre-pressure impregnation stage First, start the constant flow pump and slowly open the flow regulating valve to adjust the water flow rate to the preset pre-pressure flow rate (0.05 L / min in this embodiment). The constant flow pump delivers unpressurized water to the inlet pipe 17. After the water flow is regulated by the flow regulating valve, it slowly flows into the pressure equalization chamber 13 of the double-layer nested water distribution assembly 10 through the inlet pipe 17. Under the obstruction of the pressure equalization plate 14 and the diversion effect of the pressure equalization hole 15, the water flow entering the pressure equalization chamber 13 is evenly diffused throughout the pressure equalization chamber 13, realizing the initial equalization of water flow pressure, completely eliminating pressure fluctuations at the water inlet, and ensuring the stability of the water flow pressure flowing into the inner guide frame 12.

[0030] Then, the water, after being pressure-equalized in the pressure-equalizing chamber 13, slowly seeps into the outer wall of the inner guide frame 12, achieving secondary diversion along the micro-mesh drainage channels on the inner wall. The water spreads evenly within the drainage channels. Since the water fills the pressure-equalizing chamber 13 from bottom to top, it flows into the interior of the sealing cover plate 30 through the guide port 32, and then into the water inlet pipe 24 in the gridded guide frame 20 through the guide port 33. Part of the water flows downward along the flexible micro-guide wires 22 of the gridded guide frame 20, gradually wetting the entire three-dimensional grid structure. Another part of the water flows to the water flow guiding component 40 through the branch pipe, eventually wetting the microporous transition guide medium layer 45, gradually saturating it. During the slow flow of water, the air inside the pressure-equalizing chamber 13, the guide channel 16, the gridded guide frame 20, and other guide networks, as well as the air filling the surface of the paste sample, is... The water is squeezed and gradually flows upward, eventually being discharged through the vent at the top of the outer water distribution frame 11. This process continues until no more air bubbles are discharged from the vent, indicating that the entire flow guiding network and the microporous transition flow guiding medium layer 45 are filled with unpressurized water, completely eliminating the problems of water flow impact, air blockage, and local scouring caused by "sudden water ingress into the dry channel". At the end of the pre-pressure wetting stage, the water flow that fills the microporous transition flow guiding medium layer 45 will slowly seep into the surface of the filled paste sample through its tiny pores. After some water flows through the surface of the paste, it slowly flows into the water collection pool 52 through the bottom drainage pipe 25 of the gridded flow guiding skeleton 20. When a small amount of water is observed to seep out of the drainage pipe 25, it indicates that the pre-pressure wetting has achieved the expected effect, the flow guiding network and the microporous transition flow guiding medium layer 45 are saturated, the pre-pressure wetting stage is over, and it is ready to enter the formal experimental operation stage.

[0031] II. Trial Operation Phase First, after the pre-pressure impregnation is completed, the constant flow pump is kept running continuously, and the water flow rate is slowly adjusted through the flow regulating valve to gradually increase to the preset formal water spray flow rate (0.5L / min in this embodiment). The flow rate adjustment process is slow and stable to avoid water flow impact caused by sudden flow changes, prevent damage to the original structure of the filled paste sample, and ensure the authenticity of the experimental data.

[0032] Secondly, the water flow from the formal water spray is continuously delivered through the inlet pipe 17 to the pressure equalization chamber 13 inside the outer water distribution frame 11. Under the constraint of the outer water distribution frame 11, the water flow is fully diffused in the pressure equalization chamber 13, and the pressure is further equalized through the pressure equalization holes 15 of the pressure equalization plate 14, ensuring that the water flow pressure in each area of ​​the pressure equalization chamber 13 is consistent and the flow rate is uniform, thus achieving the first-level equalization of the water flow. After pressure equalization, the water flow is diverted a second time through the mesh drainage channel on the outer wall of the inner guide frame 12, thus achieving the second-level equalization of the water flow. Through this pressure equalization water distribution mode, the influence of water flow pressure fluctuations on the permeation test is completely eliminated, providing stable water flow conditions for subsequent gradient guidance and undisturbed permeation.

[0033] Then, the water in the equalizing chamber 13 flows into the water inlet pipe 24 in the gridded flow guide frame 20 through the inlet 33. Part of the water flows downward along the flexible micro-guide wires 22 of the gridded flow guide frame 20, gradually wetting the entire three-dimensional grid structure. The other part of the water flows to the water flow guide component 40 through the branch pipe. The water flow guide component 40 is divided into a surface wide water distribution section 42, a middle flow limiting and stabilizing section 43, and a bottom micro-permeation and slow release section 44 along the depth direction of the filled paste sample. The pore size of the internal guide channel decreases gradually from top to bottom along the depth direction of the paste (in this embodiment, it is set to 2mm for the surface layer, 1mm for the middle layer, and 0.5mm for the bottom layer), and the opening direction is obliquely tangential (in this embodiment, the angle between it and the paste surface is set to 20°). When the water flows along the guide channel, the flow rate is regulated according to the pore size gradient. The surface water flow rate is moderate and the coverage is wide, the middle water flow is stable and limited, and the bottom water flow is slowly released to avoid vertical water flow. The hydraulic fracturing of the paste causes water to flow out through the outlet of the guide channel. It then needs to pass through the microporous transition guide medium layer 45. Since the pore size of the microporous transition guide medium layer 45 is smaller than the minimum particle size of the filling paste particles, the water can only slowly seep into the interior of the filling paste sample through its tiny pores by utilizing the isolation effect of the medium. The paste particles cannot enter the guide channel. At the same time, the microporous transition guide medium layer 45 avoids direct contact between the water flow guiding component 40 and the paste, does not form an artificial strong channel, and does not change the pore structure, permeation path and permeation resistance of the paste itself. This achieves undisturbed and interference-free water flow infiltration into the paste. Moreover, the gridded guide skeleton 20 divides the filling paste sample into several uniform spatial micro-units 23. Each spatial micro-unit 23 corresponds to an independent water inlet and seepage outlet, ensuring that the water flow infiltrating the paste can be evenly distributed to every area of ​​the paste, with no dead spots or local water accumulation, achieving uniform permeation throughout the entire area.

[0034] Finally, the water that has seeped into the paste sample slowly permeates to the bottom of the paste under its own gravity and osmotic pressure. It eventually flows slowly into the water collection tank 52 through the bottom drainage pipe 25 of the gridded flow guide frame 20. Excess water that has not completely permeated, such as water that has not permeated into the paste on the surface, will also flow along the surface of the paste to the water collection tank 52, so as to achieve centralized collection of all water flow. The water in the water collection tank 52 is continuously returned to the experimental water storage device through the return pipe, so as to achieve water recycling and at the same time avoid excess water from accumulating at the bottom of the paste and forming hydrostatic pressure, which would affect the permeation test results.

[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A leaching test apparatus for filling a paste, characterized by: The system includes a double-layer nested water distribution assembly (10), the top of which is fitted with a sealing cover plate (30). The double-layer nested water distribution assembly (10) has a built-in gridded flow guide skeleton (20), which is embedded inside the filling paste. Water flow guide components (40) corresponding to the gridded flow guide skeleton (20) are uniformly connected and installed on the inner wall of the double-layer nested water distribution assembly (10). The water flow guiding component (40) is set at an oblique micro-tangential angle and is not perpendicular to the surface of the filling paste. It includes a surface wide water distribution part (42), the bottom of which is connected to a middle flow limiting and stabilizing part (43). The bottom of the middle flow limiting and stabilizing part (43) is connected to a bottom micro-permeation and slow-release part (44). A microporous transition flow guiding medium layer (45) is provided between the bottom end of the bottom micro-permeation and slow-release part (44) and the surface of the filling paste. A waterproof sealing layer is coated on the contact surface between the microporous transition flow guiding medium layer (45), the bottom end of the bottom micro-permeation and slow-release part (44), and the filling paste. The pore size of the microporous transition flow guiding medium layer (45) is smaller than the minimum particle size of the filling paste particles.

2. The leaching test device for filling paste according to claim 1, characterized in that: The double-layer nested water distribution assembly (10) includes an outer water distribution frame (11), an inner guide frame (12) is fixedly sleeved at the bottom of the outer water distribution frame (11), and a pressure equalization chamber (13) is set between the outer water distribution frame (11) and the inner guide frame (12). A pressure equalization plate (14) is uniformly fixedly arranged from bottom to top in the pressure equalization chamber (13), and pressure equalization holes (15) are uniformly opened on the pressure equalization plate (14).

3. The leaching test device for filling paste according to claim 2, characterized in that: The bottom of the outer wall of the outer water distribution frame (11) is fixedly equipped with a water inlet pipe (17), and the water inlet pipe (17) is connected to the pressure equalization chamber (13). The outer end of the water inlet pipe (17) is connected to the constant flow pump, and a flow regulating valve is installed on the water inlet pipe (17).

4. The leaching test device for filling paste according to claim 2, characterized in that: The inner guide frame (12) is provided with longitudinally arranged guide grooves (16), and the water flow guiding component (40) also includes a connector (41) that communicates with the guide grooves (16), and the connector (41) is fixedly connected to the top of the surface wide water distribution part (42).

5. The leaching test device for filling paste according to claim 4, characterized in that: The sealing cover (30) covers the top of the outer water distribution frame (11), and a sealing ring is encapsulated between the sealing cover (30) and the double-layer nested water distribution assembly (10). An inner pressure plate (31) is fixedly installed inside the sealing cover (30) and covers the top of the inner guide frame (12). A guide port (32) communicating with the pressure equalization chamber (13) is provided between the inner pressure plate (31) and the sealing cover (30). Exhaust holes are opened at the four corners of the top of the sealing cover (30).

6. The leaching test device for filling paste according to claim 5, characterized in that: The gridded flow guide frame (20) is a three-dimensional grid frame composed of several sets of microtube bundle nodes (21) and flexible micro-flow guide wires (22). It is embedded inside the filling paste and divides the filling paste into several sets of micro-units (23) with the same space without damaging the structure of the filling paste body. The top of the gridded flow guide frame (20) is provided with water inlet pipes (24) corresponding to the micro-units (23), and the bottom of the gridded flow guide frame (20) is provided with drainage pipes (25) corresponding to each set of water inlet pipes (24). The drainage pipes (25) extend out to the bottom of the double-layer nested water distribution component (10).

7. The leaching test device for filling paste according to claim 6, characterized in that: The inner pressure plate (31) has a flow port (33) that corresponds one-to-one with the water inlet pipe (24). The water inlet pipe (24) is embedded in the flow port (33) and is connected to the flow guide channel (16) through a branch pipe. It is used to guide the water to the water flow guide component (40). The water flow guide component (40) corresponds to the micro unit (23).

8. The leaching test device for filling paste according to claim 7, characterized in that: The diameter of the guiding channel inside the surface wide water distribution section (42) is 2-5mm, the diameter of the guiding channel inside the middle flow limiting and stabilizing section (43) is 1-2mm, the diameter of the guiding channel inside the bottom micro-permeation and slow release section (44) is 0.5-1mm, and the angle between the oblique micro-tangential direction of the guiding channel and the surface of the filling paste is 15-30°.

9. The leaching test device for filling paste according to claim 6, characterized in that: The water collection assembly (50) includes a fixing frame (51) fixed on the outer wall of the outer water distribution frame (11), a water collection pool (52) corresponding to the drainage pipe (25) is fixedly installed on the fixing frame (51), and a drainage pipe (53) is installed at the bottom of the water collection pool (52).

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