Monitoring device for simulating slurry invasion film formation and pollutant migration process

Abstract

The invention provides a monitoring device for simulating a slurry invasion film forming and pollutant migration process, and belongs to the technical field of environmental geotechnical engineering. Comprising a soil column permeation module used for simulating a stratum environment and providing a sealed space for mud invasion and pollutant migration; the air pressure driving module is used for providing and adjusting air pressure power for mud invasion and pollutant migration processes; the pollutant migration module is used for injecting pollution liquid into the soil layer invaded by the mud and collecting samples; the monitoring and recording module is used for collecting and recording pore water pressure, images and percolate quality data in the experiment process in real time. According to the invention, the integration of mud invasion and pollutant migration experiments is realized, the determination of key parameters is realized, the invasion film-forming rule of mud under the influence of multiple factors is dynamically revealed, the specific mechanism and quantitative evaluation of the heterogeneous mud permeation zone influencing the pollutant migration behavior are clear and definite, and the operation is simple and convenient. Therefore, key data and theoretical support are provided for evaluating and improving the overall barrier efficiency of the vertical separation wall.

Description

Technical Field

[0001] This invention provides a monitoring device for simulating the process of mud intrusion film formation and pollutant migration, belonging to the field of environmental geotechnical engineering technology. Background Technology

[0002] Bentonite-based vertical barriers, with their excellent low permeability, adsorption properties, and environmental compatibility, have become an important barrier measure for contaminated sites such as landfills and metal smelters. Engineering practice shows that during barrier construction, bentonite slurry, under pressure, infiltrates the surrounding strata, forming a "slurry infiltration zone." This zone, as an extension of the barrier, constitutes a "secondary barrier" against pollutants, and its formation quality and distribution characteristics directly determine the overall antifouling effectiveness of the barrier system.

[0003] Currently, research in this field faces two major challenges: First, the formation of mud infiltration zones is influenced by a combination of factors, including grouting pressure, mud properties, and formation gradation, resulting in complex distribution patterns (such as mud film type and intrusion zone type). The mechanisms of intrusion film formation and their spatial distribution patterns have not yet been systematically revealed. Second, how existing heterogeneous mud infiltration zones affect pollutant migration behavior, i.e., the specific mechanisms and quantitative assessments of their "pollution prevention and efficiency enhancement" effects, remain unclear. Based on these findings, this invention provides a monitoring device for simulating the process of mud intrusion film formation and pollutant migration. Summary of the Invention

[0004] The technical problem solved by this invention is that the invasion and film formation law of mud under the influence of multiple factors has not been systematically revealed, and the specific mechanism and quantitative assessment of the influence of heterogeneous mud infiltration zone on pollutant migration behavior are still unclear, making it impossible to achieve the integration of mud invasion and pollutant migration experiments.

[0005] To address the technical problem, the present invention provides a monitoring device for simulating the process of mud intrusion film formation and pollutant migration, comprising:

[0006] Soil column permeation module is used to simulate geological environments and provide a sealed space for mud intrusion and contaminant migration;

[0007] The pneumatic drive module is used to provide and regulate pneumatic power for mud intrusion and contaminant migration processes;

[0008] The pollutant migration module is used to inject contaminated liquid into soil layers that have been infiltrated by mud and to collect samples.

[0009] The monitoring and recording module is used to collect and record pore water pressure, images, and exudate quality data in real time during the experiment.

[0010] Furthermore, the soil column permeation module includes a permeation column, a grouting valve, a pressure relief valve, a pressure boosting valve, a pressure gauge, a slurry discharge valve, a mud tank, and a peristaltic pump; the permeation column has a grouting valve on its side wall, which is connected to the mud tank via the peristaltic pump; the permeation column has a pressure relief valve, a pressure boosting valve, and a pressure gauge at its top; and the permeation column has a slurry discharge valve at its bottom.

[0011] Furthermore, the permeation column is made of acrylic material, and both the top and bottom covers of the permeation column are fastened with screws and nuts to ensure the airtightness of the device.

[0012] Furthermore, the pneumatic drive module includes an air compressor, a second pressure gauge, a two-way air guide pipe, a first pressure regulating valve, a second pressure regulating valve, a first ventilation valve, and a second ventilation valve. The air compressor is equipped with a second pressure gauge for monitoring its internal air pressure. The air compressor is connected to a pressurizing valve and a second pressure regulating valve via the two-way air guide pipe. One end of the two-way air guide pipe is equipped with a first pressure regulating valve and a first ventilation valve connected to the pressurizing valve, and the other end of the two-way air guide pipe is equipped with a second ventilation valve connected to the second pressure regulating valve.

[0013] Furthermore, the contaminant migration module includes a gas-driven liquid booster connected to the second pressure regulating valve, an injection valve, a drain valve, a second liquid guide tube, an outlet valve, and a syringe; the gas-driven liquid booster is used to store the contaminated liquid and is connected to the lower part of the permeation column via the second liquid guide tube and the injection valve; the side wall of the permeation column is provided with multiple sampling ports, which are respectively connected to the corresponding outlet valves and syringes for extracting contaminated liquid at different heights; the upper part of the side wall of the permeation column is provided with a drain valve for collecting the exudate.

[0014] Furthermore, the monitoring and recording module includes a pore pressure sensor, wires, a paperless recorder, a computer, a high-speed camera, a liquid guide tube, a beaker, and an electronic scale. The pore pressure sensor is installed on the side wall of the permeation column at the same height as the syringe tube. The pore pressure sensor is connected to the paperless recorder and the computer via wires. The high-speed camera is used to record the mud intrusion process and the contaminant migration process. One end of the liquid guide tube is connected to the slurry discharge valve, and the other end of the liquid guide tube is connected to the beaker. The beaker is used to collect the pore solution and slurry discharged during the mud intrusion process.

[0015] Furthermore, the upper part of the side wall of the permeation column is provided with a drain pipe connected to the drain valve, and the end of the drain pipe is provided with a beaker two for collecting the leachate contaminated liquid so as to subsequently determine the concentration of the leachate contaminated liquid; the electronic scale is used to weigh the mass of the collected liquid in beaker one and beaker two.

[0016] The beneficial effects of this invention are:

[0017] This invention integrates mud intrusion and pollutant migration experiments, enables the determination of key parameters, dynamically reveals the intrusion and film formation patterns of mud under the influence of multiple factors, and accurately quantifies the cross-media migration behavior of pollutants in heterogeneous mud infiltration zones. The specific mechanisms and quantitative assessments of the influence of heterogeneous mud infiltration zones on pollutant migration behavior are clearly defined, thus providing key data and theoretical support for evaluating and improving the overall barrier effectiveness of vertical isolation walls. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a monitoring device for simulating the process of mud intrusion film formation and pollutant migration according to the present invention.

[0019] 1. Permeation column; 2. Grouting valve; 3. Pressure relief valve; 4. Pressure boosting valve; 5. Pressure gauge 1; 6. Pressure regulating valve 1; 7. Pore pressure sensor; 8. Drain valve; 9. Two-way venting tube; 10. Ventilation valve 1; 11. Ventilation valve 2; 12. Injection valve; 13. Grout discharge valve; 14. Pressure regulating valve 2; 15. Liquid guide tube 2; 16. Discharge valve; 17. Liquid guide tube 1; 18. Beaker 1; 19. Syringe; 20. Wire; 21. Air compressor; 22. Pressure gauge 2; 23. Paperless recorder; 24. Computer; 25. High-speed camera; 26. Screw; 27. Nut; 28. Electronic scale; 29. ​​Air-driven liquid booster; 30. Contaminated liquid; 31. Mud tank; 32. Peristaltic pump; 33. Beaker 2. Detailed Implementation

[0020] The invention will be further described below with reference to the accompanying drawings.

[0021] According to the appendix Figure 1 As shown: This invention provides a monitoring device for simulating the process of mud intrusion film formation and contaminant migration, comprising: a soil column infiltration module, used to simulate the formation environment and provide a sealed space for mud intrusion and contaminant migration; the soil column infiltration module includes an infiltration column 1, a grouting valve 2, a pressure relief valve 3, a pressure valve 4, a pressure gauge 5, a slurry discharge valve 13, a mud tank 31, and a peristaltic pump 32; the grouting valve 2 is provided on the side wall of the infiltration column 1, and is connected to the mud tank 31 through the peristaltic pump 32 for injecting mud from the mud tank 31 into the chamber of the infiltration column 1; the pressure relief valve 3 is provided at the top of the infiltration column 1. The permeation column 1 is equipped with a pressure relief valve 4 and a pressure gauge 5. A slurry discharge valve 13 is installed at the bottom of the permeation column 1 to discharge the bentonite slurry from the permeation soil layer. The permeation column 1 is made of acrylic. Due to the high requirements for the sealing of the device in the experiment, the top and bottom covers of the permeation column 1 are fastened with screws 26 and nuts 27 to ensure the sealing of the device. Specifically, a hole is drilled in the upper top cover of the permeation column 1 and a pressure relief valve 3, a pressure relief valve 4, and a pressure gauge 5 are installed. The pressure relief valve 3 is used for releasing air pressure after the experiment, the pressure relief valve 4 is used for injecting air pressure before the experiment, and the pressure gauge 5 is used to monitor changes in air pressure in the chamber.

[0022] The pneumatic drive module provides and regulates pneumatic power for the mud intrusion and contaminant migration processes. The pneumatic drive module includes an air compressor 21, a second pressure gauge 22, a two-way air guide pipe 9, a first pressure regulating valve 6, a second pressure regulating valve 14, a first ventilation valve 10, and a second ventilation valve 11. The air compressor 21 is equipped with a second pressure gauge 22 for monitoring its internal air pressure. The air compressor 21 is connected to the pressurization valve 4 and the second pressure regulating valve 14 via the two-way air guide pipe 9. One end of the two-way air guide pipe 9 is equipped with a first pressure regulating valve 6 and a first ventilation valve 10 connected to the pressurization valve 4, and the other end of the two-way air guide pipe 9 is equipped with a second ventilation valve 11 connected to the second pressure regulating valve 14. Specifically, the first ventilation valve 10 and the second ventilation valve 11 control the ventilation during the mud intrusion and contaminant migration processes, while the first pressure regulating valve 6 and the second pressure regulating valve 14 regulate the injection pressure during mud intrusion.

[0023] The contaminant migration module is used to inject contaminated liquid into the soil layer after mud intrusion and collect samples. The module includes a gas-driven liquid booster 29 connected to pressure regulating valve 14, an injection valve 12, a discharge valve 8, a guide tube 15, an outlet valve 16, and a syringe 19. The gas-driven liquid booster 29 stores contaminated liquid 30 and is connected to the lower part of the permeation column 1 via the guide tube 15 and injection valve 12. The permeation column 1 has multiple sampling ports on its side wall, each connected to a corresponding outlet valve 16 and syringe 19 for extracting contaminants at different heights. The permeation column 1 has a drain valve 8 on the upper side wall for collecting the leachate. Specifically, when air pressure is applied to the air-driven liquid booster 29, the contaminated liquid enters the permeable soil layer inside the permeation column 1 through the injection valve 12. The contaminated liquid can be extracted when the outlet valve 16 is opened using needles 19 at different positions. Finally, the contaminated liquid seeps out through the drain valve 8 and flows into beaker 2 33 through the drain pipe. The concentration of the contaminated liquid at different heights can be measured using needles 19, which is convenient for calculating the hydrodynamic dispersion coefficient and the retardation factor. The relevant parameters of the breakdown curve can be obtained from the seeping contaminated liquid.

[0024] The monitoring and recording module is used to collect and record pore water pressure, images, and exudate quality data in real time during the experiment. The module includes a pore pressure sensor 7, a wire 20, a paperless recorder 23, a computer 24, a high-speed camera 25, a liquid guide tube 17, a beaker 18, and an electronic scale 28. The pore pressure sensor 7 is installed on the side wall of the permeation column 1 at the same height as the syringe 19. The pore pressure sensor 7 is connected to the paperless recorder 23 and the computer 24 via the wire 20 to achieve real-time data acquisition of pore water pressure. The high-speed camera... 25 is used to record the mud intrusion process and the contaminant migration process; one end of the liquid guide tube 17 is connected to the slurry discharge valve 13, and the other end of the liquid guide tube 17 is connected to the beaker 18. The beaker 18 is used to collect the pore solution and slurry discharged during the mud intrusion process; the upper part of the side wall of the permeation column 1 is provided with a discharge guide tube connected to the discharge valve 8, and the end of the discharge guide tube is provided with a connected beaker 2 33 for collecting the leachate contaminant liquid so as to subsequently determine the concentration of the leachate contaminant liquid; the electronic scale 28 is used to weigh the mass of the collected liquid in the beaker 18 and the beaker 2 33.

[0025] Working principle:

[0026] Mud Intrusion Experiment

[0027] Experimental Procedure: Before the experiment, the airtightness of the apparatus must be checked; inside the permeation column 1, a certain thickness of large-diameter gravel layer and a specific particle size-graded soil layer (porosity of [missing information]) are laid sequentially from top to bottom. The pre-mixed mud is injected into the mud tank 31 and stirred evenly to prevent particle sedimentation. The mud in the mud tank 31 is pumped into the chamber of the permeation column 1 by the peristaltic pump 32. After the slurry level reaches the set height, the grouting valve 2 is closed. The air compressor 21 and the vent valve 10 are turned on, and the pressure regulating valve 6 is adjusted to make the grouting pressure reach the experimental set value. Then, open the pressurization valve 4. After the air pressure value displayed on the pressure gauge 5 meets the experimental requirements, open the slurry discharge valve 13 (drainage valve 8 and liquid outlet valve 16 remain closed during this stage). During the pressurization process, the pore pressure sensor 7 collects the pore water pressure in the soil layer in real time. The data is recorded in real time by the paperless recorder 23 and then uploaded to the computer 24 for further processing; at the same time, the liquid discharged from the slurry discharge valve 13 is collected using beaker 18 and electronic scale 28, and its volume is recorded. With quality The entire mud infiltration process is filmed using a high-speed camera 25; when the state of the infiltrated slurry stabilizes, the current grouting pressure is reached. The following experiment was conducted; subsequently, the pressure regulating valve was adjusted to a higher set pressure value. By repeating all the above experimental steps, the permeability curves of mud under different pressure conditions and the relationship curve between permeability and permeation time can be obtained. The permeability coefficient of soil layer at different times and in different sections can be calculated by using the pressure difference between pore pressure sensors 7 at different locations. The dynamic formation process of mud permeation zone can be obtained by combining the dynamic changes of permeability coefficient of soil layer in different sections with high-speed camera 25.

[0028] Data processing:

[0029] a. Calculation of permeability coefficient in different sections

[0030] 1. Determine the position and elevation of the pore pressure sensor 7: Assume the installation elevation of the pore pressure sensor 7 is calculated from top to bottom as follows: The vertical distance between two adjacent orifice pressure sensors 7 (m); (taking the readings of the two orifice pressure sensors 7 as an example)

[0031] 2. Convert pressure readings to total head: The pore pressure sensor 7 measures pore water pressure, which needs to be converted to total head before Darcy's law can be used. The formula for calculating total head at any location is:

[0032]

[0033] =Total head (m), =Local head (elevation of the point relative to the reference surface, in meters), = Pore water pressure (kPa). =The specific gravity of water, usually taken as 9.8 kN / m³

[0034] Therefore, the water heads corresponding to P1 and P2 are:

[0035]

[0036] 3. Calculate the head difference:

[0037]

[0038] 4. Calculate the permeability coefficient:

[0039]

[0040] in:

[0041] =Effluent flow rate (m³ / s) =Cross-sectional area perpendicular to the seepage direction (m²)

[0042] 5. Final Formula Summary:

[0043]

[0044] Through mud permeability experiments, different sections can be obtained. With different times permeability coefficient Obtained using different times and different sections The footage captured by the high-speed camera 25 can provide a basis for depicting the dynamic formation process of the mud infiltration zone. The soil column is divided into n segments along its height, and the data of each segment is calculated using data from adjacent pore pressure sensors 7. ,draw The contour map shows the change of permeability coefficient with time and altitude; a set of stable contour lines will be obtained in the final steady-state permeation stage. This group The value represents the final permeability coefficient of different sections when the slurry seepage rate is stable. (Definition) ,in Let k be the initial permeability coefficient for different sections. r A value less than 1 indicates a decrease in the soil permeability coefficient during mud infiltration. This decrease in permeability coefficient affects pollutant migration; therefore, k... r This improved the fouling resistance of the mud penetration zone in the later stages.

[0045] b. Identification of mud permeability zone formation based on pore pressure data

[0046] 1. Initial intrusion stage: Pore pressure rises sharply, hydraulic gradient i > critical gradient Δh can be calculated using the pore pressure sensor 7;

[0047] 2. Stable permeation stage: Pore pressure tends to stabilize, and discharge flow rate is constant;

[0048] 3. Mud film formation stage: The pore pressure in the upper layer increases, the pore pressure in the lower layer decreases, and the permeability coefficient decreases significantly;

[0049] 4. Completely closed stage: The pore pressure at each point tends to be consistent, and the discharge flow rate approaches zero.

[0050] c. Define the effective permeation zone thickness using pore pressure sensor 7.

[0051]

[0052] in:

[0053] The location where the pore pressure changes most significantly; The location where the pore pressure changes significantly;

[0054] Since the pore water pressure changes as mud particles infiltrate the formation, the depth of mud infiltration can be determined based on the location of the pore pressure change, and the thickness of the effective infiltration zone can be calculated.

[0055] Pollutant migration experiment

[0056] Experimental Procedure: After the mud intrusion experiment, close the pressurization valve 4, vent valve 10, and slurry discharge valve 13 in sequence, then open the pressure relief valve 3 to completely release the internal air pressure of the permeation column 1; open the top cover of the permeation column 1, extract the remaining slurry, and then close the top cover of the permeation column 1 again, taking care not to damage the formed mud film during the operation; then open the drain valve 8, vent valve 11, and injection valve 12, and adjust the pressure regulating valve 14 to the experimental set pressure, allowing a certain concentration of contaminated liquid in the gas-driven liquid booster 29 to migrate upwards from the bottom of the permeation column 1 and enter the soil layer where the mud intrusion zone has been formed; throughout the migration of the contaminated liquid, open the outlet valve 16 and use the syringe 19 to extract contaminated liquid at different locations for contaminant concentration measurement, ensuring that the pore water pressure in the soil layer remains stable; simultaneously, collect the permeated contaminated liquid through the drain valve 8 (collection container is beaker 33), and record the data at different times. Corresponding exudate concentration With quality This allows for the plotting of breakdown curves representing the pollutant migration process; finally, the pore water pressure data recorded by pore pressure sensor 7 at different times and locations can be combined with this data. The soil permeability coefficient after pollutant migration was calculated. This allows us to determine the chemical impact of pollutants on the mud infiltration zone.

[0057] Data processing:

[0058] a. Calculate the hydrodynamic dispersion coefficient and blocking factor

[0059] Hydrodynamic dispersion coefficient and blocking factor These are key parameters describing the migration of pollutants in porous media; they can be calculated by combining data from pore pressure sensor 7 (pore water pressure) and eluent concentration data (collected from drain valve 8). The specific steps are as follows:

[0060] 1. Calculate the pore water flow velocity :

[0061] For two adjacent sensors, the head difference is:

[0062]

[0063] Hydraulic gradient for:

[0064]

[0065] If there are enough pore pressure sensors 7, a plot can be drawn. and The curve yields a continuous hydraulic gradient distribution.

[0066] 2. Calculate Darcy velocity :

[0067] Darcy velocity It can be obtained by injection flow rate or percolation flow rate; under steady flow conditions, the injection flow rate... Controlled by the air-driven liquid booster 29.

[0068] formula:

[0069]

[0070] Where A is the cross-sectional area of ​​the cylindrical cavity.

[0071] 3. Calculate the pore water flow velocity :

[0072]

[0073] in It refers to porosity.

[0074] 4. Calculation using concentration breakthrough curve and :

[0075] The one-dimensional convection-dispersion-adsorption equation for pollutant migration is:

[0076]

[0077] in:

[0078] C is the concentration of contaminated liquid at the point of final breakdown (mg / L).

[0079] Indicates the initial concentration of the contaminated liquid (mg / L).

[0080] t is time (s).

[0081] It is the pore water flow velocity (L / s).

[0082] z represents the position (m).

[0083] It is the hydrodynamic dispersion coefficient (m 2 / s)

[0084] It is a blocking factor (dimensionless).

[0085] ERFC is the complementary error function.

[0086] The contaminated liquid can be obtained by collecting the solution through drain valve 8 and beaker 2 33. The image (breakdown curve) can be obtained by fitting it with a one-dimensional convection-dispersion-adsorption equation. and .

[0087] b. Utilizing the stable phase of contaminated liquid migration Assess the chemical effects of contaminants on the mud seepage zone.

[0088] Stable phase The calculation method is the same as that for the mud intrusion stage, and will not be repeated here. Through comparison... Compared with the stable state of the exudate during the early mud intrusion stage ,if Value less than This indicates that the presence of contaminated liquid will alter the permeability of the mud infiltration zone and reduce its fouling resistance.

[0089] c. Characterizing the fouling resistance of the mud seepage zone

[0090] The fouling resistance of mud infiltration zones can be characterized by comparing the pollutant migration parameters and dynamic behavior in control experiments with and without mud infiltration.

[0091] 1. Comparison based on migration parameters:

[0092] 1. Blocking factor : An increase in the value indicates strong adsorption capacity and good fouling resistance of the mud penetration zone. Comparison of values ​​with and without mud is needed. value;

[0093] 2 Hydrodynamic Dispersion Coefficient : A decrease in the value indicates weak dispersion, making it difficult for pollutants to diffuse and resulting in good pollution barrier performance.

[0094] 3 Value: Through The magnitude of the value indicates the change in the permeability coefficient of the soil layer after the formation of the mud seepage zone. The smaller the value, the greater the reduction in permeability coefficient, and the stronger the ability to block pollutants.

[0095] 2. Based on exudate data:

[0096] 1 Breakthrough Time The time it takes for pollutants to first reach a certain altitude (e.g., =0.1); the longer the breakthrough time, the better the fouling resistance.

[0097] 2 Peak concentration The maximum concentration of a certain highly permeable liquid; the lower the peak concentration, the better the fouling resistance.

[0098] In summary, the present invention has the following beneficial effects:

[0099] 1. Integration of mud intrusion and pollutant migration experiments: A complete set of devices enables pollutant migration experiments to be conducted in strata that have been intruded by mud and have formed mud infiltration, reducing damage to the mud infiltration zone and allowing for a more comprehensive exploration of the pollution-blocking performance of the mud infiltration zone.

[0100] 2. Determination of key parameters: During the mud intrusion stage, the permeability coefficient k of different sections was continuously measured using the pore pressure sensor 7, which systematically characterized the dynamic formation process of the mud infiltration zone; during the pollutant migration stage, the hydrodynamic dispersion coefficient was measured by extracting pollutant liquid from different sections. With blocking factor And combined with the permeability monitored by pore pressure sensor 7 The continuous variation can be used to quantitatively assess the barrier performance of the mud infiltration zone against pollutants; in addition, by comparing the changes in the permeability coefficient before and after pollutant migration, the chemical effects of pollutants on the mud infiltration zone can be further analyzed.

[0101] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A monitoring device for simulating the process of mud intrusion film formation and pollutant migration, characterized in that, include: Soil column permeation module is used to simulate geological environments and provide a sealed space for mud intrusion and contaminant migration; The pneumatic drive module is used to provide and regulate pneumatic power for mud intrusion and contaminant migration processes; The pollutant migration module is used to inject contaminated liquid into soil layers that have been infiltrated by mud and to collect samples. The monitoring and recording module is used to collect and record pore water pressure, images, and exudate quality data in real time during the experiment.

2. The monitoring device for simulating the process of mud intrusion film formation and pollutant migration according to claim 1, characterized in that: The soil column infiltration module includes an infiltration column (1), a grouting valve (2), a pressure relief valve (3), a pressure boosting valve (4), a pressure gauge (5), a slurry discharge valve (13), a mud tank (31), and a peristaltic pump (32). The side wall of the infiltration column (1) is provided with a grouting valve (2), which is connected to the mud tank (31) through the peristaltic pump (32). The top of the infiltration column (1) is provided with a pressure relief valve (3), a pressure boosting valve (4), and a pressure gauge (5). The bottom of the infiltration column (1) is provided with a slurry discharge valve (13).

3. The monitoring device for simulating the process of mud intrusion film formation and pollutant migration according to claim 2, characterized in that: The permeation column (1) is made of acrylic material. The top cover and bottom cover of the permeation column (1) are fastened with screws (26) and nuts (27) to ensure the sealing of the device.

4. The monitoring device for simulating the process of mud intrusion film formation and pollutant migration according to claim 2, characterized in that: The pneumatic drive module includes an air compressor (21), a second pressure gauge (22), a two-way air guide pipe (9), a first pressure regulating valve (6), a second pressure regulating valve (14), a first ventilation valve (10), and a second ventilation valve (11). The air compressor (21) is equipped with a second pressure gauge (22) for monitoring its internal air pressure. The air compressor (21) is connected to the pressurizing valve (4) and the second pressure regulating valve (14) respectively through the two-way air guide pipe (9). One end of the two-way air guide pipe (9) is equipped with a first pressure regulating valve (6) and a first ventilation valve (10) connected to the pressurizing valve (4). The other end of the two-way air guide pipe (9) is equipped with a second ventilation valve (11) connected to the second pressure regulating valve (14).

5. The monitoring device for simulating the process of mud intrusion film formation and pollutant migration according to claim 4, characterized in that: The contaminant migration module includes a gas-driven liquid booster (29), an injection valve (12), a drain valve (8), a guide tube (15), an outlet valve (16), and a syringe (19) connected to the pressure regulating valve (14). The gas-driven liquid booster (29) is used to store contaminated liquid (30) and is connected to the lower part of the permeation column (1) via the guide tube (15) and the injection valve (12). The side wall of the permeation column (1) is provided with multiple sampling ports, which are respectively connected to the corresponding outlet valve (16) and syringe (19) to extract contaminated liquid at different heights. The upper part of the side wall of the permeation column (1) is provided with a drain valve (8) for collecting exudate.

6. The monitoring device for simulating the process of mud intrusion film formation and pollutant migration according to claim 5, characterized in that: The monitoring and recording module includes a pore pressure sensor (7), a wire (20), a paperless recorder (23), a computer (24), a high-speed camera (25), a liquid guide tube (17), a beaker (18), and an electronic scale (28). The pore pressure sensor (7) is installed on the side wall of the permeation column (1) at the same height as the needle tube (19). The pore pressure sensor (7) is connected to the paperless recorder (23) and the computer (24) through the wire (20). The high-speed camera (25) is used to record the mud intrusion process and the pollutant migration process. One end of the liquid guide tube (17) is connected to the slurry discharge valve (13), and the other end of the liquid guide tube (17) is connected to the beaker (18). The beaker (18) is used to collect the pore solution and slurry discharged during the mud intrusion process.

7. The monitoring device for simulating the process of mud intrusion film formation and pollutant migration according to claim 6, characterized in that: The upper side wall of the permeation column (1) is provided with a drain pipe connected to the drain valve (8), and the end of the drain pipe is provided with a beaker two (33) for collecting the leached contaminated liquid so as to subsequently determine the concentration of the leached contaminated liquid; the electronic scale (28) is used to weigh the mass of the collected liquid collected in beaker one (18) and beaker two (33).

Images