A device and method for testing migration and loss of filling particles inside a karst pipeline

Abstract

The present invention provides a device and method for testing the migration and loss of filling particles inside a karst pipeline. A transparent material similar to that of the karst pipeline is filled inside a glass tube. A pressurizing module is arranged at one end of the glass tube. A colored solution is provided between the pressurizing module and the karst pipeline filling material. A sealing module is arranged at the other end of the glass tube. A permeation seam is provided in the middle of the sealing module. The pressurizing module applies pressure, so that the colored solution flows through the karst pipeline filling material, carrying the filling particles through the permeation seam and entering the seepage fluid collection pipe, and finally merging into the flow metering module. During the test, a laser is used to irradiate the karst pipeline filling material to form a laser section and perform digital photography measurement and analysis to obtain the changes in the permeation path of the colored solution and the movement changes of the particles inside the filling material; the permeability coefficient and porosity of the karst pipeline filling structure are analyzed by the water quality and particle quality of the seepage fluid; thereby studying the migration and loss patterns of the particles of the filling material inside the karst pipeline.

Description

Technical Field

[0001] This invention belongs to the technical field of karst pipelines, specifically relating to a test device and method for the migration and loss of filling particles inside karst pipelines. Background Technology

[0002] In underground engineering projects such as karst tunnels, understanding the migration and loss of infill particles within karst conduits helps engineers develop reasonable construction plans and safety measures. Due to the influence of engineering geological and hydrological conditions, the structure of infill particles within karst conduits is often very complex. This leads to various inconsistent movement, deformation, and damage characteristics after they are exposed during tunnel excavation due to seepage and erosion, inducing different types of water and mud inrush disasters. Therefore, during the geological exploration and engineering design of karst tunnels, it is necessary to consider the migration and loss patterns of infill particles within karst conduits to formulate reasonable construction plans and preventative measures.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a test device and method for the migration and loss of filling particles inside karst pipelines.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A test device for the migration and loss of filling particles inside a karst pipeline, the test device comprising:

[0007] A glass tube, which is an L-shaped transparent tube with open ends, is filled with a transparent material similar to the filling material of karst pipes, which is used to simulate the filling structure of karst pipes.

[0008] A pressurization module is disposed at one end of the glass tube, and a colored solution is provided between the pressurization module and the karst pipe filling material. The hydraulic coupling effect of the karst pipe is simulated by pressurizing the colored solution.

[0009] A plugging module is provided at the other end of the glass tube, and a permeation slit is provided in the middle of the plugging module. The permeation slit is connected to the flow metering module through a permeate collection pipe.

[0010] A laser irradiation module is located on the opposite side of the glass tube and the sealing module. The laser irradiation module is a movable red planar laser. After the laser irradiates the transparent similar material filling the karst pipe inside the glass tube, a laser cross-section is formed. An image acquisition instrument is used to continuously acquire images of the laser cross-section in front of the glass tube.

[0011] The colored solution is pressurized by the pressurization module to seep from the karst filling material to the flow metering module. The permeability coefficient and porosity of the karst pipe filling structure are analyzed by the water mass and particle mass of the seepage fluid. By continuously acquiring and digitally photographic measuring images of the laser cross-section of the karst pipe filling material during the experiment, the changes in the seepage path of the colored solution and the movement patterns of particles inside the karst pipe filling material are obtained.

[0012] Preferably, the inner wall of the glass tube is provided with an irregular concave-convex surface, and the karst filling material includes fused silica sand, amorphous silica powder, liquid paraffin, and n-tetane.

[0013] Preferably, the glass tube is disposed on one side of the fixed steel frame, the bottom of the fixed steel frame is provided with a base support for fixing the test platform, and the side of the glass tube away from the fixed steel frame is provided with an inclined brace connecting to the base support.

[0014] Preferably, the diagonal brace and the fixed steel frame are provided with a strip-shaped hole in the middle facing the glass tube. The longitudinal length of the strip-shaped hole is adapted to the height of the karst filling material. The laser emitted by the planar laser passes through the strip-shaped hole and irradiates the transparent similar material filling the karst pipe to form a laser cross-section. An image acquisition instrument is used to continuously acquire the image of the laser cross-section.

[0015] Preferably, the pressurization module includes:

[0016] The main frame has a first pressure rod pointing towards the glass tube in the middle, and a first piston plate is provided at one end of the first pressure rod that extends into the glass tube.

[0017] A pressurizing pipe, one end of which is connected to a pressurizing pump, and the other end of which passes through the first piston plate and points towards the karst pipe filling material, so as to pump a high-pressure colored solution between the first piston plate and the karst pipe filling material.

[0018] Preferably, the blocking module includes:

[0019] The second piston plate is slidably fitted onto the glass tube to abut against the karst pipe filling material, and a permeation slit is provided in the middle of the second piston plate;

[0020] The second pressure rod is supported on the corner of the second piston plate by multiple support claws;

[0021] The slide plate has a groove on one side of the second piston plate near the karst pipe filling material. The groove is located on one side of the seepage joint, and the depth of the groove is adapted to the thickness of the slide plate, so that the second piston plate has a flat surface facing the karst pipe filling material. The width of the seepage joint can be adjusted by sliding the slide plate.

[0022] The edge of the slide plate is provided with a folded portion corresponding to the seepage joint, and the side of the second piston plate away from the karst pipe filling material is provided with a limiting strip corresponding to stop the folded portion.

[0023] Preferably, the flow metering module includes a permeate collection pipe, a metering tank, a filter screen, and an electronic scale. The filter screen is positioned above the metering tank to filter out particles in the permeate.

[0024] Preferably, the testing apparatus further includes an image acquisition device and a pressure acquisition device connected to the controller;

[0025] The image acquisition device is positioned directly in front of the glass tube to continuously acquire laser cross-sectional images of the karst pipe filling material inside the glass tube; the pressure acquisition device is connected to the pressurization module and the sealing module to acquire the rated pressure data of the pressurization module and the sealing module.

[0026] A method for testing the migration and loss of particles filling the interior of a karst pipe is provided. The test is conducted using any of the aforementioned test devices. By obtaining the water mass and particle mass of the seepage fluid through the test devices, the permeability coefficient and porosity of the karst pipe filling structure can be analyzed. By continuously acquiring and analyzing laser cross-sectional images of the karst pipe filling material during the test, the changes in the infiltration path of the colored solution and the movement and changes of particles inside the filling material can be obtained.

[0027] Preferably, it includes the following steps:

[0028] Step S1: Seal the bottom of the glass tube with a temporary cover plate;

[0029] Step S2: Prepare a transparent similar material for filling karst pipes, mix multi-walled carbon nanotubes into the karst pipe filling material and fill it into the glass tube in multiple times, with a filling height of 40mm each time. After filling, put it into a vacuum chamber for 15 minutes of vacuum treatment until the filling height reaches 360mm.

[0030] Step S3: Fix the glass tube to the test bench using a fixed steel frame, and install the sealing module and pressurization module;

[0031] Step S4: Slide the sliding blockage module to close the seepage joint; turn off the colored solution pressurization pump, so that the piston plate of the pressurization module is in close contact with the karst pipe and filled with transparent similar material; apply the rated pressure to the piston plate of the pressurization module, so that the transparent similar material filling the pipe is statically solidified for the rated time under the rated consolidation pressure;

[0032] Step S5: After consolidation, turn on the planar laser and irradiate the transparent similar material filling the karst channel inside the glass tube to form a laser cross-section. Use an image acquisition instrument to continuously acquire images of the laser cross-section in front of the glass tube. By performing digital photogrammetric analysis on the acquired images, the changes in the infiltration path of the colored solution and the movement and changes of particles inside the karst channel filling material can be obtained.

[0033] Step S6: Adjust the width of the seepage joint to a predetermined value by sliding the sliding plate of the sealing module, turn on the pressurization module and the colored solution pressurization pump, so that the colored solution seeps from the top of the karst pipe filling material to the flow metering module, and discharge the seepage liquid into the metering tank after being filtered by the filter screen. Analyze the permeability coefficient and porosity of the karst pipe filling structure by the water quality and particle quality of the seepage liquid.

[0034] Step S7: Stop the experiment, turn off the instrument, and clean and store the instrument.

[0035] Beneficial Effects: A transparent, similar material was used to simulate the filling structure of karst pipes. A pressurization module was used to pressurize the material, allowing a colored solution to flow through the filling material, carrying the filling particles through the seepage joints and into the seepage collection pipe, ultimately flowing into the flow metering module. During the experiment, a laser was used to irradiate the filling material to create a laser cross-section, and digital photographic measurement and analysis were performed to obtain the changes in the colored solution's seepage path and the movement patterns of particles within the filling material. The permeability coefficient and porosity of the karst pipe filling structure were analyzed using the water mass and particle mass of the seepage fluid, thus allowing for the study of the particle migration and loss patterns within the karst pipe filling material. Attached Figure Description

[0036] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0037] Figure 1 This is a schematic diagram of the experimental apparatus in a specific embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of the assembly of the glass tube in a specific embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the assembly of the slide plate and the second piston plate in a specific embodiment of the present invention;

[0040] Figure 4 This is a simplified structural diagram of the skateboard in a specific embodiment of the present invention;

[0041] Figure 5 This is a simplified side view of the fixed steel frame in a specific embodiment of the present invention.

[0042] In the diagram: 1. Digital camera; 2. Pressure pipe; 3. Glass tube; 4. Transparent similar material used to fill the karst pipe; 5. Measuring tank; 6. Filter screen; 7. Image acquisition instrument and pressure acquisition instrument; 8. Fixed steel frame; 9. Main frame; 10. First pressure rod; 11. First piston plate; 12. Controller; 13. Injection pressurizer; 14. Water pump; 15. Oil pump; 16. Strip hole; 17. Diagonal brace; 18. Second pressure rod; 19. Second piston plate; 20. Limiting strip; 21. Slide plate; 22. Folding part; 23. Seepage seam; 24. Planar laser; 25. Electronic scale; 26. Test bench; 27. Seepage collection pipe. Detailed Implementation

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0044] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0045] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0046] like Figure 1-5As shown, to study the migration and loss patterns and deformation and failure characteristics of particles inside a karst pipeline filling structure under hydraulic coupling, this application provides an experimental device for the migration and loss of particles inside a karst pipeline filling structure. The experimental device includes a glass tube 3, a pressurization module, a sealing module, and a laser irradiation module. The glass tube 3 is a transparent tube with open ends. The glass tube 3 is preferably made of plexiglass and is a square tube formed by bonding multiple plexiglass sheets. The glass tube 3 is filled with a transparent similar material 4 for karst pipeline filling. Fused silica sand is used to simulate gravel and sand particles in the karst pipeline filling material, and amorphous silica powder is used to simulate... The clay particles in the karst conduit filling material are simulated by mixing liquid paraffin and n-tetane at a mass ratio of 1:0.85 to simulate the pore water in the karst conduit filling structure. This is used to simulate the filling material of the karst channel. A pressurization module is set at one end of the glass tube 3. A colored solution is placed between the pressurization module and the transparent similar material 4 used to fill the karst conduit, in order to simulate the internal pore water in the karst conduit filling material. The colored solution can be a mineral oil solution with 1% light blue dye. By pressurizing the colored solution, it is allowed to permeate through the transparent similar material 4 used to fill the karst conduit, thus simulating the hydraulic coupling effect of the karst conduit.

[0047] A sealing module is located at the other end of the glass tube 3. A permeation slit 23 is provided in the middle of the sealing module to discharge the permeate that has passed through the transparent similar material 4 filling the karst pipe. The permeation slit 23 is connected to the flow metering module through the permeate collection pipe 27. The flow metering module separates the water and particles in the permeate. In response to the pressurization by the pressurization module, the colored solution permeates from the karst pipe filling material 4 to the flow metering module. The permeability coefficient and porosity of the karst pipe filling structure are analyzed by the water mass and particle mass of the permeate, so as to study and observe the migration and loss law of the filling particles inside the karst pipe.

[0048] In this embodiment, the colored solution is prepared by mixing liquid paraffin and n-tetane at a mass ratio of 1:0.85 and adding 1% light blue dye. The refractive indices of the fused silica sand, amorphous silica powder and the colored solution are basically the same, thus avoiding errors caused by image acquisition.

[0049] In an optional embodiment, the glass tube 3 is L-shaped, with an outer length of 250mm, a height of 450mm, a thickness of 150mm, and an inner surface with irregular concave and convex surfaces. The inner space cross-sectional dimension is approximately a square glass tube with a side length of 100mm, and an outer steel frame fixing device. This is used to simulate the irregular curved karst pipe with an actual inner surface. The karst pipe is filled with a transparent similar material 4, which includes fused silica sand, amorphous silica powder, liquid paraffin, and n-tetane, with a mass ratio of 1:5:5:4.25.

[0050] Fused silica sand was used to simulate gravel and sand particles in the karst tunnel filling material, amorphous silica powder was used to simulate clay particles, and a mineral oil solution (a mixture of liquid paraffin and n-tetrane at a mass ratio of 1:0.85) was used to simulate internal pore water. When the glass tube 3 is filled with a transparent similar material to the karst tunnel filling structure, it can be combined with a digital photogrammetry system to observe and analyze the migration patterns and deformation and failure characteristics of particles inside the karst tunnel filling structure.

[0051] Specifically, based on the composition and particle size distribution curve of the actual karst pipeline filling structure medium, the incorporation mass and particle size range of fused silica sand and amorphous silica powder are determined. They are then mixed with mineral oil solution and subjected to vacuum treatment to prepare a transparent similar material for karst pipeline filling.

[0052] In an optional embodiment, the glass tube 3 is disposed on one side of the fixed steel frame 8. The fixed steel frame 8 is used to ensure the safety and stability of the L-shaped glass tube 3 under test loading. It is fixed to the steel plate of the test bench 26 using a "diagonal brace" method. Specifically, the bottom of the fixed steel frame 8 is provided with a bottom support for fixing the test bench 26. The side of the glass tube 3 away from the fixed steel frame 8 is provided with a diagonal brace 17 connected to the bottom support. The two ends of the diagonal brace 17 are fixed to the bottom support and the fixed steel frame 8 by bolts.

[0053] The test bench 26 is composed of a steel plate on the test bench 26 and a bottom support frame. The steel plate on the test bench 26 is 1200mm long and 500mm wide, and mainly provides a test operation platform for the pressurization module and the sealing module.

[0054] In addition, a water passage hole is reserved at the position of the seepage joint 23 of the sealing module on the test bench 26, so that the water and particles flowing out of the seepage collection pipe 27 can be introduced into the flow metering module below through the loss collection port.

[0055] Specifically, a guide plate or guide groove is provided at the lower end of the glass tube 3 or at the outlet of the permeation seam 23 of the sealing module, so that the permeate is collected and guided to the flow metering module through the permeate collection pipe 27 below.

[0056] In this embodiment, the bottom support platform is 600mm high. The main purpose is to ensure the stability of the visualization seepage test system for the filling structure of the deep-buried karst tunnel and to provide a height space to facilitate test operation.

[0057] In an optional embodiment, the diagonal brace 17 and the fixed steel frame 8 are provided with a strip hole 16 facing the glass tube 3 in the middle. The longitudinal length of the strip hole 16 is adapted to the height of the karst pipe filling material 4, so as to ensure that the planar laser emitted by the laser 24 can penetrate the entire glass tube 3. After the laser emitted by the laser 24 passes through the strip hole 16, it irradiates the transparent similar material 4 filling the karst pipe to form a laser cut surface.

[0058] The experimental setup also includes an image acquisition device and a pressure acquisition device 7, which are connected to the controller 12. The image acquisition device is a digital camera 1, which faces the glass tube 3 to acquire images of the karst conduit filling material 4 inside the glass tube 3. The laser 24 emits laser light to create laser spots on the internal planar surface of the transparent similar material of the karst conduit filling structure. The digital camera 1, connected to a computer, is responsible for acquiring the laser-created images at fixed times and locations. The controller 12 can be a PC, pre-installed with data processing software. The software analyzes the acquired experimental images for aspects such as seepage path, particle migration, and deformation and failure characteristics of the filling material.

[0059] Furthermore, the pressure acquisition instrument is connected to both the pressurization module and the sealing module to collect their pressure readings. The instrument uses pressure sensors and a pressure gauge for this purpose. Specifically, two sets of pressure sensors are installed on the first pressurization rod 10 and the second pressurization rod 18, respectively, for pressure data acquisition. The pressure gauge is located on the pressurization pipe 2 to collect internal hydraulic data, including pressure at the inlet and outlet of the glass tube 3 and water pressure on the inner wall. This data is used to analyze the water pressure, hydraulic gradient, and sliding force of the karst pipe filling structure. Connecting the pressure acquisition instrument to a computer allows the data collected by the system to be stored for subsequent experimental data analysis.

[0060] In an optional embodiment, the pressurization module includes a main frame 9 and a pressurization tube 2. The main frame 9 is fixed to the test bench 26 by bolts. A first pressurization rod 10 pointing towards the glass tube 3 is provided in the middle of the main frame 9. The first pressurization rod 10 can be any of a screw, worm gear, hydraulic rod, or pneumatic cylinder solenoid rod. A first piston plate 11 is provided at one end of the first pressurization rod 10 that extends into the glass tube 3. The first piston plate 11 is a square structure corresponding to the inner cavity of the upper end of the glass tube 3, including multiple square plates with rubber layers between them. Alternatively, the first piston plate 11 has a certain thickness, and two layers of rubber waterstop strips are sleeved around the outer ring of the first piston plate 11 to form a piston structure.

[0061] This forms a piston structure. Two pressurization pipes are provided on the first piston plate 11 for connecting the pressurization pipes 2. One end of the pressurization pipe 2 is connected to a pressurization pump, and the other end passes through the first piston plate 11 and points towards the karst pipe filled with transparent similar material 4, so as to pump high-pressure colored solution into the space between the first piston plate 11 and the karst pipe filled with transparent similar material 4.

[0062] The pressurizing pump mainly consists of an oil pump 15, a water pump 14, an injection pressurizer 13, pipelines, and connecting joints. The injection pressurizer 13 has a pressurizing piston on the inner wall of a piston cylinder. One end of the piston cylinder corresponding to the pressurizing piston is connected to the oil pump 15, and the other end of the side wall is connected to the pressurizing pipe 2 through a three-way valve. The other end of the three-way valve is connected to the water pump 14 through a shut-off valve and a reversing valve. The water pump 14 is connected to the colored solution holding tank. A shut-off valve is provided on the pressurizing pipe 2 between the three-way valve and the glass tube 3.

[0063] In an optional embodiment, the seepage joint 23 of the sealing module can be adjusted in width, thereby simulating different seepage fissure widths and support forces at the outlet of the karst pipeline filling structure by adjusting the width of the seepage joint 23.

[0064] The sealing module includes a second piston plate 19, a second pressure rod 18, and a sliding plate 21. The second piston plate 19 is a square plate corresponding to its lower end, and its outer wall is fitted with two layers of rubber waterstop strips. It is slidably assembled with the glass tube 3 to form a piston structure. Driven by the second pressure rod 18, it abuts against the transparent similar material 4 filling the karst pipe, thereby preventing the transparent similar material 4 filling the karst pipe from shifting. A seepage slit 23 is provided in the middle of the second piston plate 19. The seepage slit 23 is a rectangular hole. A sliding plate 21 is provided on the seepage slit 23 to adjust the width of the seepage slit 23. The second pressure rod 18 can be any one of a screw, worm gear, hydraulic rod, or cylinder-moving electromagnetic rod.

[0065] The second pressure rod 18 is supported by multiple claws at the corners of the second piston plate 19, so as not to affect the installation and sliding of the slide plate 21.

[0066] In an optional embodiment, the infiltration slot 23 is a rectangular hole located in the middle of the second piston plate 19. The second piston plate 19 has a groove on the side near the karst pipe filled with transparent similar material 4. The length of the groove is adapted to the length of the infiltration slot 23, so that the sliding plate 21 can slide in the groove to block the infiltration slot 23. The width of the blocked part can be adjusted to block the infiltration slot 23. The groove is located on one side of the infiltration slot 23, and the depth of the groove is adapted to the thickness of the sliding plate 21. This makes the second piston plate 19 have a flat surface facing the karst pipe filled with transparent similar material 4, thereby ensuring that the second piston plate 19 can fit tightly against the karst pipe filled with transparent similar material 4.

[0067] In this embodiment, the edge of the slide plate 21 is provided with a folded portion 22 corresponding to the infiltration seam 23. The length of the folded portion 22 is adapted to the length of the infiltration seam 23, and the width is adapted to the depth of the infiltration seam 23. The side of the folded portion 22 away from the karst pipe filled with transparent similar material 4 is on the same plane as the side of the second piston plate 19 away from the karst pipe filled with transparent similar material 4. The side of the second piston plate 19 away from the karst pipe filled with transparent similar material 4 is provided with a limiting strip 20 corresponding to stop the folded portion 22, thereby blocking and limiting the folded portion 22 to avoid the slide plate 21 tilting due to excessive pressure.

[0068] In an optional embodiment, the flow metering module includes a metering tank 5, a filter screen 6, and an electronic scale 25. The filter screen 6 is disposed above the metering tank 5 to filter out particles in the permeate, thereby measuring the mass of water and particles respectively.

[0069] In an optional embodiment, this application also provides a method for testing the loss of particles inside a karst pipeline. The test is conducted using any of the above-mentioned test devices. By obtaining the water mass and particle mass of the seepage fluid from the test devices, the permeability coefficient and porosity of the karst pipeline filling structure can be analyzed.

[0070] Specifically, the following steps are included:

[0071] Step S1: The bottom of the glass tube 3 is sealed by vertically inserting a permeable stone and using a temporary cover plate (with multiple regularly spaced small holes for drainage).

[0072] Step S2: Prepare the transparent similar material 4 for filling karst pipes according to the type of filling structure medium. Mix 0.5% by mass of multi-walled carbon nanotubes into the transparent similar material 4 for filling karst pipes and fill it into the glass tube 3 in multiple times. Each filling height is 40mm. After filling, put it into a vacuum chamber for 15 minutes of vacuum treatment until the filling height reaches 360mm.

[0073] Step S3: Fix the glass tube 3 to the test bench 26 using the fixed steel frame 8, and install the sealing module and pressurization module.

[0074] Step S4: The sliding sealing module slide plate 21 closes the seepage joint 23, and the colored solution pressurization pump is turned off, so that the pressurization module piston plate is in close contact with the karst pipe filled with transparent similar material 4; the rated pressure is applied to the pressurization module piston plate, so that the transparent similar material filling the pipe is statically solidified for a rated time under the rated consolidation pressure.

[0075] Step S5: After consolidation, connect the injection pressurizer 13 to the pressurization tube 2 and open the valve between them. Turn on the planar laser to irradiate the transparent similar material 4 filling the karst channel inside the glass tube to form a laser cut surface. Use an image acquisition device to continuously acquire images of the laser cut surface directly in front of the glass tube 3. Control the computer to make the digital camera 1 acquire images of the spot plane at regular intervals, with the acquisition speed set to 1 image per second. Turn on the data acquisition device and electronic scale 25 to collect the pressure and permeate mass of each part. By performing digital photographic measurement and analysis on the acquired images, obtain the changes in the permeation path of the colored solution and the movement and change of particles inside the karst channel filling material.

[0076] In step S6, the width of the seepage joint 23 is adjusted to a predetermined value by sliding the slide plate 21 of the sealing module. The pressurization module and the colored solution pressurization pump are turned on, and the injection pressurizer 13 is driven by the oil pump 15 to gradually increase the water pressure inside the glass tube 3, with each pressurization step increasing by 0.1 MPa. After pressurization, the pressure is stabilized for 600 seconds. The support pressure value of the second pressurization rod 18 is increased synchronously according to the applied water pressure value until the design support pressure is reached. During the gradual loading of water pressure, the colored solution seeps from the transparent similar material 4 filling the karst pipe to the flow metering module. The seepage liquid is filtered through the filter screen 6 and discharged into the metering tank 5. When particles begin to appear on the filter screen 6, the filter screen 6 is replaced every 60 seconds until the filling structure experiences a sudden water inrush or instability. The permeability coefficient and porosity of the karst pipe filling structure are analyzed by the water quality and particle quality of the seepage liquid.

[0077] Step S7: Stop the experiment, turn off the instrument, and clean and store the instrument.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be within the scope of protection of the pending claims of the present invention.

Claims

1. A test device for the migration and loss of particles filling the interior of a karst pipeline, characterized in that, The test apparatus includes: A glass tube, which is an L-shaped transparent tube with open ends, is filled with a transparent material similar to the filling material of karst pipes, which is used to simulate the filling structure of karst pipes. A pressurization module is disposed at one end of the glass tube, and a colored solution is provided between the pressurization module and the karst pipe filling material. The hydraulic coupling effect of the karst pipe is simulated by pressurizing the colored solution. A plugging module is provided at the other end of the glass tube, and a permeation slit is provided in the middle of the plugging module. The permeation slit is connected to the flow metering module through a permeate collection pipe. A laser irradiation module is located on the opposite side of the glass tube and the sealing module. The laser irradiation module is a movable red planar laser. After the laser irradiates the transparent similar material filling the karst pipe inside the glass tube, a laser cross-section is formed. An image acquisition instrument is used to continuously acquire images of the laser cross-section in front of the glass tube. The colored solution is pressurized by the pressurization module to seep from the karst filling material to the flow metering module. The permeability coefficient and porosity of the karst pipe filling structure are analyzed by the water mass and particle mass of the seepage fluid. By continuously acquiring and digitally photographic measuring images of the laser cross-section of the karst pipe filling material during the experiment, the changes in the seepage path of the colored solution and the movement patterns of particles inside the karst pipe filling material are obtained.

2. The test device for the migration and loss of particles filling the interior of a karst pipeline according to claim 1, characterized in that, The inner wall of the glass tube is configured with an irregular concave-convex surface, and the karst filling material includes fused silica sand, amorphous silica powder, liquid paraffin, and n-tetane.

3. The test device for the migration and loss of particles filling the interior of a karst pipeline according to claim 1, characterized in that, The glass tube is positioned on one side of the fixed steel frame, and the bottom of the fixed steel frame is provided with a base support for fixing the test platform. The side of the glass tube away from the fixed steel frame is provided with an inclined brace that connects to the base support.

4. The test device for the migration and loss of particles filling the interior of a karst pipeline according to claim 3, characterized in that, The diagonal brace and the fixed steel frame are provided with a strip-shaped hole in the middle facing the glass tube. The longitudinal length of the strip-shaped hole is adapted to the height of the karst filling material. The laser emitted by the planar laser passes through the strip-shaped hole and irradiates the transparent similar material filling the karst pipe to form a laser cross-section. An image acquisition instrument is used to continuously acquire the laser cross-section image.

5. The test device for the migration and loss of particles filling the interior of a karst pipeline according to claim 1, characterized in that, The pressurization module includes: The main frame has a first pressure rod pointing towards the glass tube in the middle, and a first piston plate is provided at one end of the first pressure rod that extends into the glass tube. A pressurizing pipe, one end of which is connected to a pressurizing pump, and the other end of which passes through the first piston plate and points towards the karst pipe filling material, so as to pump a high-pressure colored solution between the first piston plate and the karst pipe filling material.

6. The test device for the migration and loss of particles filling the interior of a karst pipeline according to claim 1, characterized in that, The blocking module includes: The second piston plate is slidably fitted onto the glass tube to abut against the karst pipe filling material, and a permeation slit is provided in the middle of the second piston plate; The second pressure rod is supported on the corner of the second piston plate by multiple support claws; The slide plate has a groove on one side of the second piston plate near the karst pipe filling material. The groove is located on one side of the seepage joint, and the depth of the groove is adapted to the thickness of the slide plate, so that the second piston plate has a flat surface facing the karst pipe filling material. The width of the seepage joint can be adjusted by sliding the slide plate. The edge of the slide plate is provided with a folded portion corresponding to the seepage joint, and the side of the second piston plate away from the karst pipe filling material is provided with a limiting strip corresponding to stop the folded portion.

7. The test device for the migration and loss of particles filling the interior of a karst pipeline according to claim 1, characterized in that, The flow metering module includes a permeate collection pipe, a metering tank, a filter screen, and an electronic scale. The filter screen is positioned above the metering tank to filter out particles in the permeate.

8. The test device for the migration and loss of particles filling the interior of a karst pipeline according to claim 4, characterized in that, The test apparatus also includes an image acquisition device and a pressure acquisition device that are connected to the controller. The image acquisition device is positioned directly in front of the glass tube to continuously acquire laser cross-sectional images of the karst pipe filling material inside the glass tube; the pressure acquisition device is connected to the pressurization module and the sealing module to acquire the rated pressure data of the pressurization module and the sealing module.

9. A method for testing the migration and loss of filling particles inside a karst pipeline, wherein the test is conducted using the testing apparatus described in any one of claims 1-8, characterized in that... By obtaining the water mass and particle mass of the seepage fluid from the experimental device, the permeability coefficient and porosity of the karst conduit filling structure can be analyzed. By continuously acquiring laser cross-sectional images of the karst conduit filling material during the experiment and performing digital photogrammetric analysis, the changes in the infiltration path of the colored solution and the movement patterns of particles inside the filling material can be obtained.

10. The test method for the migration and loss of filling particles inside karst pipes according to claim 9, characterized in that, Includes the following steps: Step S1: Seal the bottom of the glass tube with a temporary cover plate; Step S2: Prepare a transparent similar material for filling karst pipes, mix multi-walled carbon nanotubes into the karst pipe filling material and fill it into the glass tube in multiple times, with a filling height of 40mm each time. After filling, put it into a vacuum chamber for 15 minutes of vacuum treatment until the filling height reaches 360mm. Step S3: Fix the glass tube to the test bench using a fixed steel frame, and install the sealing module and pressurization module; Step S4: Slide the sliding blockage module to close the seepage joint; turn off the colored solution pressurization pump, so that the piston plate of the pressurization module is in close contact with the karst pipe and filled with transparent similar material; apply the rated pressure to the piston plate of the pressurization module, so that the transparent similar material filling the pipe is statically solidified for the rated time under the rated consolidation pressure; Step S5: After consolidation, turn on the planar laser and irradiate the transparent similar material filling the karst channel inside the glass tube to form a laser cross-section. Use an image acquisition instrument to continuously acquire images of the laser cross-section in front of the glass tube. By performing digital photogrammetric analysis on the acquired images, the changes in the infiltration path of the colored solution and the movement and changes of particles inside the karst channel filling material can be obtained. Step S6: Adjust the width of the seepage joint to a predetermined value by sliding the sliding plate of the sealing module, turn on the pressurization module and the colored solution pressurization pump, so that the colored solution seeps from the top of the karst pipe filling material to the flow metering module, and discharge the seepage liquid into the metering tank after being filtered by the filter screen. Analyze the permeability coefficient and porosity of the karst pipe filling structure by the water quality and particle quality of the seepage liquid. Step S7: Stop the experiment, turn off the instrument, and clean and store the instrument.

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