Two-dimensional infiltration channel hidden way filter material filling drainage test device and method

Abstract

The application discloses a two-dimensional permeation groove hidden way filter material filling drainage test device and method, which comprises a permeation mechanism, a water supply mechanism connected with the permeation mechanism and providing water source for the permeation mechanism, and an overflow mechanism connected with the permeation mechanism; the permeation mechanism comprises a support frame, a permeation box arranged on the support frame, a water-permeable partition plate arranged above the inside of the permeation box, a hidden way arranged in the inside of the permeation box, and a water injection port, a hidden way water outlet, a salt detection hole, an overflow port and a pressure measuring hole arranged on the permeation box respectively, the hidden way is filled with sand and gravel filter material, and the pressure measuring hole is connected with a pressure measuring component through a pipeline. The device adopts a hydraulic permeation box to carry out indoor mechanical clogging backwashing experiment, realizes multi-dimensional control and monitoring of the permeation process, observes and analyzes water flow change, clogging condition and stability of the hidden way structure in the drainage process by simulating actual soil conditions and combining the filter material filling and the hidden way system, so that the recovery condition of the clogging condition is judged, and the device is convenient and reliable.

Description

Technical Field

[0001] This invention relates to the field of underground drainage technology, specifically to a two-dimensional permeation tank underground channel filter media filling drainage test device and method. Background Technology

[0002] Underground drainage is a simple, cost-effective flood control technology, but it is susceptible to damage due to freeze-thaw cycles. To address potential issues such as reduced drainage efficiency, clogging, and collapse in underground drainage systems, this study aims to improve the drainage performance and stability of underground pipe systems. An indoor mechanical clogging and backwashing test was conducted using a self-made hydraulic infiltration tank. By simulating actual soil conditions, the drainage performance, stability, and soil retention of underground pipe systems filled with gravel filter media were evaluated, thus assessing the high-efficiency drainage performance of the underground pipes.

[0003] Commonly used indoor infiltration and clogging test devices have certain limitations in simulating infiltration and clogging of sand and gravel filter media in underground channels. This is because they cannot reflect the effects of slope and channel spacing on the drainage effect and stability after the sand and gravel filter media is filled in the underground channels. Furthermore, the monitoring time for clogging of the sand and gravel filter media in the underground channels is relatively short, and it cannot accurately reflect the clogging situation of the sand and gravel filter media reverse filter layer. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a two-dimensional permeation tank culvert filter media filling and drainage test device and method.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a two-dimensional permeation tank underground channel filter media filling drainage test device, including a permeation mechanism, a water supply mechanism connected to the permeation mechanism and providing a water source for the permeation mechanism, and an overflow mechanism connected to the permeation mechanism;

[0006] The permeation mechanism includes a support frame, a permeation tank mounted on the support frame, a permeable baffle mounted above the inside of the permeation tank, a tunnel inside the permeation tank, and water inlets, tunnel outlets, salinity detection holes, overflow ports, and pressure measuring holes mounted on the permeation tank. The tunnel is filled with gravel filter media. The pressure measuring holes are connected to a pressure measuring component via pipes. The tunnel outlet is connected to the tunnel. The water inlets are located at the upper and lower parts of the permeation tank, and the overflow port is located at the upper end of the permeation tank.

[0007] Furthermore, the pressure testing assembly includes a movable base, a bracket mounted on the movable base, a pressure testing plate mounted on the bracket, and multiple pressure testing tubes mounted on the pressure testing plate with openings at both the top and bottom. The pressure testing tubes are connected to the pressure testing holes via pipes.

[0008] Furthermore, the infiltration box is provided with multiple card slots, in which cards are inserted, and gaps are formed between adjacent cards, which are configured as hidden channels.

[0009] Furthermore, the water supply mechanism includes a support base, a column mounted on the support base, and a water supply tank connected to the column by a locking clamp. The water supply tank is connected to the water inlet via a pipe.

[0010] Furthermore, the overflow mechanism includes a water collection tank and an overflow pipe connecting the water collection tank and the overflow port.

[0011] Furthermore, the support frame includes a frame body, a support platform located at the upper end of the frame body, and a pulley with brakes located at the lower end of the frame body, with the infiltration box located on the support platform.

[0012] Furthermore, limiting members are provided at the four corners of the support platform to prevent the permeation chamber from shifting, and the limiting members are respectively attached to the adjacent sides of the permeation chamber.

[0013] This invention also provides a method for filling and draining filter media in a two-dimensional infiltration tank, which uses a testing device and includes the following steps:

[0014] S1: Determine the gradation of the filter media filled into the duct;

[0015] S2: The filter media determined in S1 is filled into the permeation tank using a layered filling method, and the air is vented and water is injected from the water inlet at the bottom of the permeation tank through the water supply mechanism.

[0016] S3: Let the permeation tank stand until it reaches saturation, then slowly inject water through the water inlet at the top of the permeation tank and control the water level through the overflow outlet.

[0017] S4: After the water injection is completed, the air bubbles in the pressure testing tubes are expelled, so that the water columns in all the pressure testing tubes are at the same height;

[0018] S5: Begin the experiment, and conduct analysis on the flow rate attenuation in the culvert, the permeability of the gravel filter media, the soil retention performance of the gravel filter media, and the anti-clogging performance of the gravel filter media.

[0019] Furthermore, when determining the filter media gradation in step S1, the following steps are included:

[0020] S1.1: Determine the basic properties of the soil;

[0021] S1.2: The filter media gradation was determined using the Sherrard 1989 method and the Tersa criteria;

[0022] S1.3: Screening filter media, screening filter media in each particle size range according to the required particle size;

[0023] S1.4: Mix the filter media. Mix the sieved filter media evenly.

[0024] Further, step S2 includes the following steps:

[0025] S2.1: Lay a layer of quartz sand 2cm-4cm thick and 2mm-4mm in diameter;

[0026] S2.2: Place a permeable partition and lay filter paper on the permeable partition;

[0027] S2.3: Calculate the required dry soil weight for each layer of the soil column filled with soil according to the required unit weight;

[0028] S2.4: Then, the soil is filled in layers and compacted with a tamper to ensure the uniformity of soil density and good contact between adjacent layers.

[0029] S2.5: The water supply method adopts bottom-up water injection. Water is slowly injected into the infiltration tank through the water injection port at the bottom of the infiltration tank, gradually permeating the soil upward and expelling gas.

[0030] S2.6: After the soil in the infiltration chamber is completely soaked, the next layer is filled. After each layer is filled, saturation venting is performed. After the last layer of soil is filled, a layer of filter paper and a permeable baffle are placed on top, and then saturation venting is performed.

[0031] The present invention has the following beneficial effects: The present invention provides a two-dimensional infiltration tank culvert filter media filling drainage test device. This device uses a hydraulic infiltration tank to carry out indoor mechanical clogging backwashing experiments, realizing multi-dimensional control and monitoring of the infiltration process. By simulating actual soil conditions, combined with filter media filling and culvert system, the device observes and analyzes the changes in water flow, clogging situation and stability of culvert structure during drainage, thereby judging the recovery of clogging situation, and further exploring effective prevention and control measures to alleviate mechanical clogging of soda saline-alkali soil culvert filled with gravel filter media. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the present invention;

[0033] Figure 2 This is a front view of the permeation chamber in this invention;

[0034] Figure 3 This is a right view of the permeation chamber in this invention;

[0035] Figure 4 This is a schematic diagram of the penetration method process in this invention;

[0036] Figure 5 This is a gradation curve of soil and filter media in this invention;

[0037] Figures 1 to 5The reference numerals in the attached drawings are as follows: 1-permeation mechanism, 2-water supply mechanism, 3-overflow mechanism, 10-support frame, 11-permeation tank, 12-permeable baffle, 13-underground channel, 14-water inlet, 15-underground channel outlet, 16-salt detection hole, 17-overflow port, 18-pressure measuring hole, 19-pressure measuring component, 190-moving base, 191-bracket, 192-pressure measuring plate, 193-pressure measuring pipe, 20-support base, 21-column, 22-water supply tank, 30-water collection bucket, 31-overflow pipe, 100-frame, 101-support platform, 102-limiting component. Detailed Implementation

[0038] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0039] like Figure 1 As shown, a two-dimensional infiltration tank with filter media filling and drainage test device (channel 13) includes an infiltration mechanism 1, a water supply mechanism 2 connected to and providing a water source for the infiltration mechanism 1, and an overflow mechanism 3 connected to the infiltration mechanism 1. The infiltration mechanism 1 is the core component of the test device, mainly used to simulate and observe two-dimensional seepage phenomena, especially the drainage effect after the filter media in channel 13 is filled. It provides a controllable seepage environment so that researchers can accurately measure and analyze seepage characteristics. During use, an appropriate amount of soil and filter media in channel 13 are filled into the infiltration tank to simulate actual geological conditions. Water is injected into the infiltration tank through the water supply mechanism 2 to form a stable seepage field. The flow of water through the filter media and soil during the seepage process is observed and recorded, including parameters such as flow velocity and flow rate. The water supply mechanism 2 provides a stable water source for the infiltration mechanism 1, ensuring the continuous seepage process. It can also control the flow rate and pressure of the water source to adapt to different test requirements. The flow rate and pressure of the water source are adjusted according to the test requirements to form a stable seepage field, and the water supply is monitored to ensure the smooth progress of the test. The overflow mechanism 3 is used to collect and discharge excess water exceeding the capacity of the infiltration tank to prevent water overflow and affecting the test results. It can also be used to monitor and measure the drainage volume to evaluate the drainage efficiency of the filter media in channel 13. The overflow mechanism 3 ensures moisture balance during the test, preventing water overflow from affecting the test results. Simultaneously, by monitoring and measuring the drainage volume, the drainage efficiency of the filter media in channel 13 can be accurately evaluated, providing data support for optimizing filter media design and improving drainage performance.

[0040] like Figures 2 to 3As shown, the permeation mechanism 1 includes a support frame 10, a permeation chamber 11 mounted on the support frame 10, a permeable baffle 12 positioned above the interior of the permeation chamber 11, a channel 13 inside the permeation chamber 11, and an injection port 14, a channel outlet 15, a salinity detection port 16, an overflow port 17, and a pressure measuring port 18 respectively mounted on the permeation chamber 11. The channel 13 is filled with gravel filter media. The pressure measuring port 18 is connected to a pressure measuring component 19 via a pipe. The channel outlet 15 is connected to the channel 13. The injection ports 14 are located at the upper and lower parts of the permeation chamber 11, and the overflow port 17 is located at the upper end of the permeation chamber 11. The support frame 10 is the supporting structure for the entire permeation mechanism 1, used to fix and support the permeation chamber 11, ensuring its stability and safety during the test and avoiding test errors caused by shaking or tilting. The infiltration chamber 11 is the main part of the experimental setup, housing components such as the permeable baffle 12, the underground channel 13, and the gravel filter media, forming a closed infiltration environment. Before the experiment begins, the permeable baffle 12, the underground channel 13, and the gravel filter media are installed inside the infiltration chamber 11 according to design requirements. Then, water is injected into the infiltration chamber 11 through the water inlet 14, creating a seepage field. The permeable baffle 12 is located at the top inside the infiltration chamber 11, separating the water source from the gravel filter media, preventing direct scouring of the filter media by the water source, while allowing water to permeate through the baffle into the filter media below. It also prevents saturation venting and soil erosion during the infiltration process. When water is injected into the infiltration chamber 11 through the water inlet 14, the water first contacts the permeable baffle 12. Under the action of the baffle, the water is evenly distributed into the gravel filter media below, forming a stable seepage field. The underground channel 13 is located inside the infiltration chamber 11 to simulate groundwater channels. Gravel filter media is filled in the tunnel 13, serving both filtering and drainage functions. This allows for direct observation and analysis of water flow changes, clogging, and the stability of the tunnel 13 structure during drainage. Water inlet 14 above the infiltration chamber 11 is used for drainage tests of the tunnel 13, allowing water to infiltrate and wash away salt. Water inlet 14 below is used during backfilling to allow for saturation and air release. Overflow outlet 17 works in conjunction with upper inlet 14 to control the infiltration water. Water discharged from the tunnel 13 is collected at tunnel outlet 15, and its flow rate and turbidity are measured. Salt content detection hole 16 measures soil salinity changes to analyze desalination patterns and effectiveness. Pressure measurement hole 18 measures water head at different locations, calculates the permeability coefficient, and analyzes changes in the permeability coefficient at different times and locations.

[0041] The pressure measuring assembly 19 includes a movable base 190, a bracket 191 mounted on the movable base 190, a pressure measuring plate 192 mounted on the bracket 191, and multiple pressure measuring tubes 193 mounted on the pressure measuring plate 192 with openings at both the top and bottom. The pressure measuring tubes 193 are connected to the pressure measuring port 18 via pipes. The movable base 190 is the foundation of the pressure measuring assembly 19, used to support and fix components such as the bracket 191, pressure measuring plate 192, and pressure measuring tubes 193. It provides sufficient stability and load-bearing capacity to ensure the normal operation of the pressure measuring assembly 19 during the test. The bracket 191 is a key component connecting the movable base 190 and the pressure measuring plate 192, used to support and fix the pressure measuring plate 192 and the pressure measuring tubes 193 on it. It provides the necessary strength and rigidity to ensure that the pressure measuring plate 192 does not deform or shift during the measurement process. The pressure measuring plate 192 is one of the core components of the pressure measuring assembly 19, used to directly bear and measure the water pressure inside the permeation tank 11. When the water pressure inside the permeation chamber 11 changes, the pressure measuring plate 192 experiences a corresponding pressure. This pressure is transmitted to the pressure measuring tube 193 through the pipe connecting the pressure measuring hole 18 and the pressure measuring tube 193, and is then converted into a measurable signal such as a pressure value. Multiple pressure measuring tubes 193 on the pressure measuring plate 192 are connected to the pressure measuring hole 18 through pipes, ensuring that the water pressure inside the permeation chamber 11 is accurately transmitted to the pressure measuring tubes 193. The pressure measuring tube 193 connects the pressure measuring plate 192 and a measuring instrument such as a pressure gauge, transmitting the water pressure inside the permeation chamber 11 to the measuring instrument for measurement. It typically has sufficient inner diameter and length to ensure that no blockage or leakage occurs during measurement. The pressure measuring tube 193, with its open top and bottom, is connected to the pressure measuring plate 192 and the pressure measuring hole 18. When the water pressure inside the permeation chamber 11 changes, this pressure is transmitted through the pressure measuring plate 192 to the pressure measuring tube 193 and then along the pipes to the measuring instrument. After receiving this pressure signal, the measuring instrument converts it into a readable pressure value. The pressure measuring tube 193 can accurately transmit the water pressure inside the permeation tank 11 to the measuring instrument for measurement, providing researchers with precise data support.

[0042] The infiltration chamber 11 contains multiple slots into which cards are inserted. Gaps are formed between adjacent cards, creating channels 13. The slots, located inside the chamber 11, secure and support the cards, ensuring they do not move or deform during the experiment. By adjusting the number and position of the cards, different shapes and sizes of channels 13 can be flexibly created to simulate groundwater passages. After the cards are inserted into the slots, gaps are formed between adjacent cards; these gaps, acting as channels 13, separate and guide the water flow. By adjusting the number and position of the cards, groundwater passages of different shapes and sizes can be simulated, allowing for the study of seepage characteristics under different conditions. These gaps, acting as channels 13, are the main pathways for water flow within the chamber 11. They simulate the flow path of groundwater in soil or rock strata. By observing and analyzing the flow of water within these channels 13, seepage characteristics under different conditions can be studied.

[0043] The water supply mechanism 2 includes a support base 20, a column 21 mounted on the support base 20, and a water supply tank 22 connected to the column 21 by a locking clamp. The water supply tank 22 is connected to the water inlet 14 via a pipe. The locking clamp is an important connecting component between the column 21 and the water supply tank 22. It provides a reliable connection and fixation, allowing the water supply tank 22 to be securely installed on the column 21 and preventing it from shaking or falling off during use. The water supply tank 22 is one of the core components of the water supply mechanism 2. It is used to store and supply water, ensuring that the water supply mechanism 2 can continuously and stably supply water. During the operation of the water supply mechanism 2, the water supply tank 22 is connected to the water inlet 14 via a pipe. When water is needed, water is injected into the water supply tank 22 and transported to the water inlet 14 via a pipe. Subsequently, the water flows through the water inlet 14 into the infiltration tank 11 or other components that require water supply. During the water supply process, the water supply tank 22 maintains a certain water level and pressure to ensure the stability and continuity of the water flow.

[0044] The overflow mechanism 3 includes a water collection tank 30 and an overflow pipe 31 connecting the water collection tank 30 and the overflow port 17. The water collection tank 30 is the main component of the overflow mechanism 3, used to collect and store excess water flowing out of the overflow port 17. The overflow pipe 31 connects the water collection tank 30 and the overflow port 17, serving as the channel for water to flow from the overflow port 17 to the water collection tank 30. When the water pressure or flow rate in the system exceeds a preset value, the overflow port 17 opens, allowing excess water to pass through. This excess water then flows into the water collection tank 30 through the overflow pipe 31. During the overflow process, the water collection tank 30 continuously receives and stores this water until the water pressure or flow rate in the system returns to normal levels.

[0045] The support frame 10 includes a frame body 100, a support platform 101 located at the upper end of the frame body 100, and pulleys with brakes located at the bottom end of the frame body 100. The permeation chamber 11 is mounted on the support platform 101. Limiting members 102 are provided at the four corners of the support platform 101 to prevent the permeation chamber 11 from shifting. The limiting members 102 are respectively attached to adjacent sides of the permeation chamber 11. The pulleys are located at the bottom end of the frame body 100 to facilitate the movement and positioning of the support frame 10. The brakes are used to fix the support frame 10 when needed, preventing it from sliding or moving. The limiting members 102 are located at the four corners of the support platform 101 to prevent the permeation chamber 11 from shifting during placement or use, ensuring the safety and accuracy of the test or operation.

[0046] like Figure 4 As shown, the present invention also provides a method for filling and draining filter media in a two-dimensional infiltration tank, which uses a test apparatus and includes the following steps:

[0047] S1: Determine the gradation of the filter media filled into the duct 13;

[0048] Step S1 specifically includes the following steps:

[0049] S1.1: Determine the basic properties of the soil; understand the basic physical and chemical properties of the soil, such as particle size distribution, density, and moisture content, to provide a basis for the selection of subsequent filter media gradation. Ensure that the selection of filter media matches the soil characteristics to improve the overall efficiency of the infiltration system.

[0050] S1.2: The Sherrard 1989 method and Terzaghi's standard are used to determine the filter media gradation. These two methods scientifically determine the particle size distribution of the filter media to ensure its filtration efficiency and permeability. Optimizing the filter media gradation improves filtration accuracy and permeability while reducing the risk of clogging.

[0051] Step S1.2 is exemplified below:

[0052] Existing test soil samples were collected, and soil particle size distribution data are shown in Table 1. Filter media gradation was calculated using the Sherrard 1989 method and the Terzaghi standard, and the results are shown in Table 1. Soil and filter media gradation curves were plotted. Figure 5 .

[0053] Table 1

[0054]

[0055]

[0056] S1.3: Screening the filter media. The filter media within each particle size range is screened according to the required particle size. Screening ensures the filter media meets design requirements. This improves the uniformity and consistency of the filter media, ensuring stable operation of the permeation system.

[0057] The specific operating steps for S1.3 are as follows:

[0058] The filter media were screened using existing laboratory sieves with sizes of 0.08, 0.1, 0.2, 0.6, 1, 2, 4, 8, 12, and 20 mm as an example.

[0059] S1.3.1: Based on soil particle size data, the filter media gradation curve was calculated and determined using the Sherrard reverse filtration criterion 1989 method and the Terzaghi standard. The filter media gradation curve is shown in Figure a.

[0060] S1.3.2 Using sieve size as the x-axis on the filter media gradation curve ( Figure 1 Points are taken on the green curve, and the corresponding vertical axis represents the percentage of filter media mass smaller than the sieve aperture size, as shown in Table 2, "Percentage of filter media mass smaller than a certain particle size (%)".

[0061] For example, if the sieve specification is 0.2mm, find the point with the horizontal coordinate of 0.2 in Figure a, and then find the corresponding vertical coordinate value, which is 15 in Figure a; if the sieve specification is 0.6mm, find the point with the horizontal coordinate of 0.6 in Figure a, and then find the corresponding vertical coordinate value, which is 34 in Figure a; the same applies to other sieve specifications.

[0062] S1.3.3: Calculate the percentage of filter media mass in each particle size range. The percentage is obtained by subtracting the percentage of filter media mass smaller than a given particle size from the next two values. For example: Particle size range: 0.2-0.6 mm, mass percentage: 34-15=19 (%); Particle size range: 0.6-1 mm, mass percentage: 46-34=12 (%). See Table 2 for "Percentage of Filter Media Mass in Each Particle Size Range (%)".

[0063] S1.3.4: Indoor screening of filter media, taking a total filter media weight of 1000g as an example; if the weight is greater than 1000g, multiply by a proportional coefficient. That's it. Calculate the mass of filter media in each particle size range for a total of 1000g of filter media, as shown in Table 2, "Mass of each particle size range per 1000g of mixed filter media (g)". For example, 0.2-0.6mm, 1000 × 19% = 190 (g); 0.6-1mm, 1000 × 12% = 120 (g).

[0064] Table 2 Filter Media Sieving Table

[0065]

[0066] S2: The filter media determined in S1 is filled into the permeation tank 11 by layered filling, and the air is vented and water is injected from the water inlet 14 at the bottom of the permeation tank 11 through the water supply mechanism 2.

[0067] Step S2 specifically includes the following steps:

[0068] S2.1: Lay a layer of quartz sand 2cm-4cm thick and 2mm-4mm in diameter;

[0069] S2.2: Place the permeable baffle 12 and lay filter paper on the permeable baffle 12;

[0070] S2.3: Calculate the required dry soil weight for each layer of the soil column filled with soil according to the required unit weight;

[0071] S2.4: Then, the soil is filled in layers and compacted with a tamper to ensure the uniformity of soil density and good contact between adjacent layers.

[0072] Layered filling ensures uniform distribution of filter media and soil within the infiltration chamber 11, while simultaneously improving soil density and interlayer contact quality. This enhances the overall stability and permeability of the infiltration system and reduces resistance during the infiltration process.

[0073] S2.5: A bottom-up water supply method is adopted. Water is slowly injected into the infiltration tank 11 through the water inlet 14 at the bottom of the infiltration tank 11, gradually permeating the soil and expelling gas. By injecting water from the bottom up, the soil is gradually permeated and gas is expelled, ensuring close contact between the soil and the filter media. This reduces air bubble interference during the infiltration process and improves the accuracy and reliability of the infiltration system.

[0074] S2.6: After the soil in the infiltration chamber 11 is completely soaked, the next layer is filled. Saturation air is vented after each layer is filled. After the last layer of soil is completed, a layer of filter paper and a permeable baffle 12 are placed on top, followed by saturation air release. Saturation air release after each layer of soil is filled ensures that the soil and filter media reach saturation, reducing water loss during infiltration. This improves the water use efficiency of the infiltration system and ensures the accuracy of the test results.

[0075] S3: Let the permeation tank 11 stand until it reaches the saturation requirement, then slowly inject water through the water inlet 14 above the permeation tank 11, and control the water level through the overflow outlet 17.

[0076] S4: After the water injection is completed, the air bubbles in the pressure measuring tube 193 are expelled, so that the water columns in all pressure measuring tubes 193 are at the same height;

[0077] S5: Begin the experiment, conducting flow attenuation analysis of channel 13, permeability analysis of gravel filter media, soil retention performance analysis of gravel filter media, and anti-clogging performance analysis of gravel filter media. A comprehensive evaluation of the performance of the filter media gradation in permeation chamber 11 will provide a scientific basis for optimized design and improvement.

[0078] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. 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 two-dimensional permeation tank with underground filter media filling and drainage test device, characterized in that, It includes an infiltration mechanism (1), a water supply mechanism (2) connected to the infiltration mechanism (1) and providing a water source for the infiltration mechanism (1), and an overflow mechanism (3) connected to the infiltration mechanism (1); The permeation mechanism (1) includes a support frame (10), a permeation tank (11) disposed on the support frame (10), a permeable baffle (12) disposed above the inside of the permeation tank (11), a culvert (13) disposed inside the permeation tank (11), and a water inlet (14), a culvert outlet (15), a salinity detection hole (16), an overflow outlet (17), and a pressure measuring hole (18) respectively disposed on the permeation tank (11). The culvert (13) is filled with gravel filter media. The pressure measuring hole (18) is connected to the pressure measuring component (19) through a pipe. The culvert outlet (15) is connected to the culvert (13). The water inlet (14) is located at the upper and lower parts of the permeation tank (11) respectively. The overflow outlet (17) is located at the upper end of the permeation tank (11). The pressure measuring assembly (19) includes a movable base (190), a bracket (191) disposed on the movable base (190), a pressure measuring plate (192) disposed on the bracket (191), and multiple pressure measuring tubes (193) disposed on the pressure measuring plate (192) with openings at both the top and bottom. The pressure measuring tubes (193) are connected to the pressure measuring hole (18) through pipes. The infiltration box (11) is provided with multiple card slots, and cards are inserted into the card slots. A gap is formed between adjacent cards, and the gap is configured as a hidden channel (13).

2. The two-dimensional permeation tank underground channel filter media filling drainage test device according to claim 1, characterized in that, The water supply mechanism (2) includes a support base (20), a column (21) set on the support base (20), and a water supply tank (22) connected to the column (21) by a locking clamp. The water supply tank (22) is connected to the water inlet (14) through a pipe.

3. The two-dimensional permeation tank underground channel filter media filling drainage test device according to claim 1, characterized in that, The overflow mechanism (3) includes a water collection tank (30) and an overflow pipe (31) connecting the water collection tank (30) and the overflow port (17).

4. The two-dimensional permeation tank underground channel filter media filling drainage test device according to claim 1, characterized in that, The support frame (10) includes a frame (100), a support platform (101) located at the upper end of the frame (100), and a pulley with a brake located at the bottom end of the frame (100). The infiltration box (11) is located on the support platform (101).

5. The two-dimensional permeation tank underground channel filter media filling drainage test device according to claim 4, characterized in that, The four corners of the support platform (101) are provided with limiting members (102) to prevent the permeation tank (11) from shifting. The limiting members (102) are respectively attached to the adjacent sides of the permeation tank (11).

6. A method for filling and draining filter media in a two-dimensional infiltration tank, characterized in that, The test is conducted using the test apparatus according to any one of claims 1 to 5, comprising the following steps: S1: Multiple card slots are provided in the permeation box (11), and cards are inserted in the card slots. A gap is formed between adjacent cards, and the gap is configured as the dark channel (13). By adjusting the number and position of the cards, dark channels (13) of different shapes and sizes can be flexibly formed. The gradation of the filter media filled into the dark channel (13) is determined. S2: The filter material determined in S1 is filled into the permeation tank (11) by layered filling, and water injection and air release are carried out from the water inlet (14) at the bottom of the permeation tank (11) through the water supply mechanism (2); S3: Let the permeation tank (11) stand until it reaches the saturation requirement, then slowly inject water through the water inlet (14) above the permeation tank (11), and control the water level height through the overflow port (17); S4: After the water injection is completed, the air bubbles in the pressure measuring tube (193) are discharged so that the water columns in all pressure measuring tubes (193) are at the same height; S5: Start the experiment and conduct flow attenuation analysis of the underground channel (13), permeability analysis of gravel filter media, soil retention performance analysis of gravel filter media, and anti-clogging performance analysis of gravel filter media.

7. The two-dimensional permeation tank underground channel filter media filling and drainage test method according to claim 6, characterized in that, When determining the filter media gradation in step S1, the following steps are included: S1.1: Determine the basic properties of the soil; S1.2: The filter media gradation was determined using the Sherrard 1989 method and the Tersa criteria; S1.3: Screening filter media, screening filter media in each particle size range according to the required particle size.

8. The two-dimensional permeation tank underground channel filter media filling and drainage test method according to claim 6, characterized in that, Step S2 includes the following steps: S2.1: Lay a layer of quartz sand 2cm-4cm thick and 2mm-4mm in diameter; S2.2: Place a permeable partition (12) and lay filter paper on the permeable partition (12); S2.3: Calculate the required dry soil weight for each layer of the soil column filled with soil according to the required unit weight; S2.4: Then, the soil is filled in layers and compacted with a tamper to ensure the uniformity of soil density and good contact between adjacent layers. S2.5: The water supply method is to inject water from bottom to top. Water is slowly injected into the infiltration tank (11) through the water inlet (14) at the bottom of the infiltration tank (11), gradually permeating the soil upward and expelling gas. S2.6: After the soil in the infiltration box (11) is completely soaked, the next layer is filled. After each filling, saturation venting is performed. After the last layer of soil is filled, a layer of filter paper and a permeable partition (12) are covered on top, and then saturation venting is performed.

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