Device and method for testing vertical permeability coefficient of filter membrane of drain board

Abstract

The invention relates to the technical field of geosynthetic material testing, and discloses a test device and a test method for a vertical permeability coefficient of a drain board filter membrane, the test device comprises a sample sealing system, a pressurization system, a water supply system, a water pressure difference measurement and control system, a seepage water measurement and control system and a data processing module; the data processing module is configured to obtain water head difference, flow and time parameters so as to calculate the vertical permeability coefficient of the filter membrane of the sample piece. According to the invention, the composite in-situ test of the drain board filter membrane can be realized; the test sample sealing system is matched with the pressurizing system, so that the test can be directly carried out on a complete drainage plate without stripping a filter membrane; the combination of the water pressure difference measurement and control system and the seepage water measurement and control system realizes the automatic monitoring of water head difference and flow, the calculation is implemented through the data processing module, the accuracy and efficiency of the test are improved, and the test result can truly reflect the seepage performance of the filter membrane in the actual working state.

Description

Technical Field

[0001] This invention relates to the field of geosynthetic material testing technology, specifically a device and method for testing the vertical permeability coefficient of a drainage board filter membrane. Background Technology

[0002] Plastic drainage boards are widely used geosynthetic materials in soft soil foundation reinforcement, and their performance is mainly determined by the core board and filter membrane. The vertical permeability coefficient of the filter membrane is a key indicator for evaluating the drainage efficiency of the drainage board and directly affects the foundation reinforcement effect. Traditional testing methods usually require peeling the filter membrane from the core board and testing it separately. However, anti-clogging plastic drainage boards use a hot-melt bonding process to firmly bond the filter membrane to the core board, forming an integrated structure. While this structure enhances the bonding strength, it makes it impossible to peel the filter membrane without damage. Forced peeling will damage the integrity of the filter membrane, change its permeability characteristics, and distort the test results. At the same time, the peeled filter membrane cannot simulate the state of bonding with the core board in actual operation, and the test conditions differ significantly from real working conditions. Current testing operations are cumbersome, inefficient, and lack testing standards for hot-melt bonded drainage boards. Summary of the Invention

[0003] In view of this, the present invention provides a device and method for testing the vertical permeability coefficient of a drainage board filter membrane, so as to solve the problems mentioned in the background art.

[0004] In a first aspect, the present invention provides a device for testing the vertical permeability coefficient of a drainage board filter membrane, comprising: The sample sealing system includes a permeation overflow chamber, an upper pressure cap, and a base. The upper pressure cap and the base are disposed in the permeation overflow chamber and are adapted to jointly press the sample. A permeation channel is provided through the center of the base, and a lower permeation chamber is connected below the permeation channel. The pressurization system is adapted to apply vertical pressure to the upper pressure cap, bringing the upper pressure cap close to the base to pressurize the sample. The water supply system includes a water tank, a flow control valve, and an inlet pipe. The inlet end of the inlet pipe is connected to the water tank, and the outlet end is connected to the lower permeation chamber. The flow control valve is installed on the inlet pipe to control the inlet flow rate. The height of the inlet of the inlet pipe is higher than the height of the permeation overflow chamber. A water pressure differential measurement and control system includes an upstream pressure transmitter and a downstream pressure transmitter. The upstream pressure transmitter is connected to the lower permeation chamber, and the downstream pressure transmitter is connected to the permeation overflow chamber. A permeate monitoring and control system includes a permeate collection chamber and a collection pressure transmitter. The permeate collection chamber is connected to the permeate overflow chamber to collect overflow water. The collection pressure transmitter is located in the permeate collection chamber to monitor pressure changes. The data processing module is connected to the water pressure difference measurement and control system and the permeate measurement and control system via signal lines, and is configured to acquire water head difference, flow rate and time parameters to calculate the vertical permeability coefficient of the filter membrane of the sample.

[0005] Beneficial effects: This application enables in-situ composite testing of plastic drainage board filter membranes; through the combination of a sample sealing system and a pressurization system, testing can be performed directly on the intact drainage board without peeling off the filter membrane, solving the problem of non-destructive testing due to thermal fusion bonding. The setting of the inlet pipe in the water supply system above the permeate overflow chamber ensures stable upstream water pressure. The combination of the water pressure difference monitoring and control system and the permeate water monitoring and control system enables automatic monitoring of head difference and flow rate. Calculations are then performed through the data processing module, improving the accuracy and efficiency of the test. The test results accurately reflect the permeation performance of the filter membrane under actual working conditions.

[0006] In one optional embodiment, the pressurization system includes a pressure regulating drive, a piston rod, and a first pull rod. The piston rod is fixedly connected to the drive end of the pressure regulating drive and is connected to the upper pressure cover via the first pull rod. The pressure regulating drive is adapted to drive the piston rod to push the upper pressure cover closer to the base to apply pressure to the sample. Both the piston rod and the first pull rod are vertically arranged.

[0007] Beneficial effects: The vertical transmission design of the pressure regulating drive, piston rod, and first pull rod can apply uniform, controllable, and vertically downward pressure to the sample, ensuring the stability and accuracy of pressure transmission. On the one hand, it ensures that the sample sealing system can effectively seal the non-test area and prevent water flow short circuit. On the other hand, it can simulate the real lateral pressure of soil on the drainage board, so that the filter membrane is in a stress state close to the actual engineering situation during the test, thereby improving the reliability of the test data.

[0008] In one optional embodiment, the system further includes a base and a bracket, the bracket being fixedly disposed on the upper end of the base, and the permeation chamber being installed on the upper end of the bracket; the bracket is provided with a plurality of second pull rods, and the mounting end of the pressure regulating drive is fixedly disposed with all the second pull rods; the second pull rods are vertically disposed, and the piston rod and the first pull rod are disposed on the inner side of all the second pull rods.

[0009] Beneficial effects: The combination of the base, bracket, and second tie rod can jointly establish a stable and rigid support frame; the pressure regulating drive is installed on the second tie rod, and the piston rod and the first tie rod are placed inside it, making the force distribution of the entire pressurization system more reasonable and effectively reducing the vibration or off-center load that may occur during the test; it ensures that the device can maintain high stability and repeatability in long-term tests and tests under different pressure conditions, providing a favorable structural foundation for obtaining accurate and reproducible test results.

[0010] In one optional embodiment, the sample sealing system further includes a first sealing gasket and a second sealing gasket. The first sealing gasket is fixedly disposed on the side of the upper pressure cap facing the base. The first sealing gasket has a circular seepage channel in the middle, and the radial dimension of the circular seepage channel is the same as the radial dimension of the seepage channel in the center of the base. The second sealing gasket is fixedly disposed on the side of the base facing the upper pressure cap.

[0011] Beneficial effects: The first and second sealing gaskets, as sealing components, are fixed to the upper cover and base, respectively. Under the action of the pressurization system, the high filling capacity of the sealing material is used to tightly adhere to the non-test areas on the upper and lower surfaces of the drainage board sample to form an effective water-proof layer. This arrangement ensures that water flows only through the effective area of ​​the filter membrane defined by the base permeation channel, and does not leak from the edges or other non-test areas, thereby effectively limiting the permeation area. At the same time, it guides the water flow through the filter membrane and seeps from both sides of the drainage board core plate, ensuring the reliability of the calculated vertical permeability coefficient of the filter membrane of the sample.

[0012] In one optional embodiment, the water pressure differential measurement and control system further includes a pressure measuring tube and a measuring element, the measuring element being disposed on the pressure measuring tube to measure the water head height of the pressure measuring tube; the first pressure measuring end of the pressure measuring tube is connected to the upstream pressure transmitter, and the second pressure measuring end is connected to the downstream pressure transmitter.

[0013] Beneficial effects: The device can achieve automatic data acquisition through the upstream pressure transmitter, and also forms an independent measurement design through the pressure measuring tube and measuring element; by using the added measuring element and pressure measuring tube, a more intuitive and reliable head difference can be provided for manual observation and calibration benchmark; this design allows the operator to verify and calibrate the readings of the electronic sensor on-site at any time, and can promptly detect and correct any zero drift or error that may exist in the pressure transmitter, which helps to enhance the reliability of the head difference parameter and the long-term measurement accuracy of the device.

[0014] In one optional embodiment, the differential pressure measurement and control system further includes a first tee and a second tee. The first tee is installed on the lower permeation chamber, with its first interface connected to the lower permeation chamber, its second interface connected to the upstream pressure transmitter, and its third interface connected to the first pressure measuring end of the pressure measuring tube. The second tee is installed on the permeation overflow chamber, with its first interface connected to the permeation overflow chamber, its second interface connected to the downstream pressure transmitter, and its third interface connected to the second pressure measuring end of the pressure measuring tube.

[0015] Beneficial effects: This scheme uses a first tee and a second tee for fluid connection, connecting the upstream and downstream pressure transmitters for automatic measurement and the two measuring ends of the manually calibrated pressure measuring tube to the lower permeation chamber and the permeation overflow chamber to achieve dynamic calibration. This connection method ensures that the two measurement systems measure the water pressure at the same location, providing a benchmark for data comparison and enabling convenient and reliable implementation of the device's calibration function.

[0016] In one optional embodiment, the water supply system further includes a level gauge, a heating wire, and a condenser; the level gauge is installed inside the water tank to monitor the water level inside the tank; the heating wire is spirally wound inside the water tank, and the condenser is disposed inside the water tank and spaced apart from the heating wire; the heating wire and the condenser are adapted to regulate the water temperature inside the water tank to a constant temperature state.

[0017] Beneficial effects: The introduction of level gauges, heating wires, and condensers ensures that the water supply system can provide a constant water flow. Since water viscosity is highly sensitive to temperature, temperature changes directly lead to fluctuations in the calculated permeability coefficient. Maintaining a stable water level through level gauges, combined with closed-loop temperature control via heating wires and condensers, eliminates testing errors caused by water temperature variations. This design improves the standardization of testing conditions and the comparability of experimental results from different times and experiments, making the data more reasonable and accurate.

[0018] In one optional embodiment, the permeate collection chamber is arranged around the outer periphery of the permeate overflow chamber, and the permeate collection chamber is provided with a drain outlet, which is spaced apart from the collection pressure transmitter.

[0019] Beneficial effects: By surrounding the permeate overflow chamber with a permeate collection chamber, a water collection and metering space is formed, ensuring that all water overflowing from the permeate overflow chamber is completely collected, avoiding metering errors caused by local stagnation or splashing; the collection pressure transmitter accurately calculates the flow rate by monitoring the pressure change caused by the rise in water level in this sealed collection chamber. Compared with traditional volume readings, it is more sensitive, easier to automate, and reduces human reading errors.

[0020] Secondly, the present invention also provides a testing method for a drainage board filter membrane vertical permeability coefficient testing device, comprising the following steps: Cut a sample piece to the specified size; The saturated specimen is installed on the base, and vertical pressure is applied by the pressurization system so that the upper cover and the base press together to press the specimen. Open the flow control valve and inject constant temperature water into the permeation chamber through the inlet pipe. Observe and remove air bubbles until the permeation overflow chamber overflows. Adjust the flow control valve to stabilize the head difference between upstream and downstream, start the data processing module to collect data, start collecting infiltration water, and stop when the collected water volume reaches the preset condition. The data processing module calculates the vertical permeability coefficient of the filter membrane in the sample based on the collected head difference, flow rate, and time.

[0021] Beneficial effects: This test method obtains the vertical permeability coefficient of the filter membrane of the sample through sample preparation, saturation, sealing, water injection and venting, and automatic testing and calculation. This method can ensure the consistency of the test process and the repeatability of the results, so that different operators and different times can obtain comparable data by following this method, so as to carry out standardized, non-destructive, and in-situ accurate determination of the vertical permeability coefficient of the filter membrane of the sample.

[0022] In one alternative implementation, during the permeation test, the head difference is manually observed using the pressure measuring tube and measuring element of the water pressure difference measurement and control system, and compared with the collected head difference data to calibrate the head difference.

[0023] Beneficial effects: While automating data acquisition, operators can manually compare the data through the pressure measuring tubes of the differential pressure measurement and control system to obtain original, more reliable head difference data; it can verify the validity of the data during testing, and can also monitor the degradation of sensor performance during long-term use of the equipment, which helps to discover potential errors and ensure that the entire testing device has accurate measurement performance. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the drainage board filter membrane vertical permeability coefficient testing device according to an embodiment of the present invention; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a partial schematic diagram of the vertical permeability coefficient testing device for drainage board filter membrane according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the first sealing gasket in the drainage plate filter membrane vertical permeability coefficient testing device according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the sample in the vertical permeability coefficient testing device for drainage plate filter membrane according to an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached figures: 1. Base; 2. Bracket; 3. Permeation overflow chamber; 401. First sealing gasket; 402. Second sealing gasket; 5. Sample piece; 6. Upper pressure cap; 7. Base; 8. Permeation water collection chamber; 9. First pull rod; 10. Piston rod; 11. Pressure regulating drive; 12. Second pull rod; 13. Lower permeation chamber; 14. Collection pressure transmitter; 151. Upstream pressure transmitter; 152. Downstream pressure transmitter; 16. Pressure measuring tube; 17. Measuring element; 18. Data processing module; 19. Inlet pipe; 20. Water tank; 21. Level gauge; 22. Heating wire; 23. Condenser; 24. Drain outlet; 251. First tee fitting; 252. Second tee fitting; 26. Flow control valve; 27. Signal line. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0029] According to an embodiment of the present invention, in one aspect, a device for testing the vertical permeability coefficient of a drainage board filter membrane is provided, which includes a sample sealing system, a pressurization system, a water supply system, a water pressure difference measurement and control system, a permeate water measurement and control system, and a data processing module 18. The data processing module 18 is connected to the water pressure difference measurement and control system and the permeate water measurement and control system via a signal line 27, and is configured to acquire head difference, flow rate, and time parameters to calculate the vertical permeability coefficient of the filter membrane of the sample 5.

[0030] In a specific implementation, the sample sealing system is used to fix and seal the sample 5 and form a seepage channel and space; specifically, such as Figures 1 to 3 , Figure 5As shown, the sample sealing system includes a permeation overflow chamber 3, an upper pressure cap 6, and a base 7. The upper pressure cap 6 and the base 7 are disposed within the permeation overflow chamber 3 and are adapted to jointly press against the sample 5. A permeation channel is provided through the center of the base 7, and a lower permeation chamber 13 is connected below the permeation channel. The permeation channel is used to define the permeation area. The base 7 may have a permeation channel with an inner diameter of 80 mm, the inner diameter of which defines the permeation area A to be tested. The upper pressure cap 6 is a solid structure. The pressurization system is adapted to apply vertical pressure to the upper pressure cap 6, bringing the upper pressure cap 6 close to the base 7 to pressurize the sample 5. By applying vertical pressure through the pressurization system, the filter membrane in the non-test area is sealed, forming a water-proof layer that prevents water from flowing through the filter membrane in that area, leaving the unsealed filter membrane surface completely exposed to the water flow.

[0031] In specific implementation methods, such as Figures 2 to 5 As shown, the sample sealing system also includes a first sealing gasket 401 and a second sealing gasket 402. The first sealing gasket 401 is fixedly disposed on the side of the upper pressure cover 6 facing the base 7. A circular seepage channel is provided in the middle of the first sealing gasket 401, and the radial dimension of the circular seepage channel is the same as the radial dimension of the seepage channel in the center of the base 7. The second sealing gasket 402 is fixedly disposed on the side of the base 7 facing the upper pressure cover 6. The first sealing gasket 401 and the second sealing gasket 402 serve as sealing parts and are fixed to the upper pressure cover 6 and the base 7, respectively. Under the action of the pressurization system, the high filling capacity of the sealing material is used to tightly adhere to the non-test areas on the upper and lower surfaces of the drainage board sample to form an effective water-proof layer. This arrangement ensures that the water flow only passes through the effective area of ​​the filter membrane defined by the seepage channel of the base 7 and does not leak from the edges or other non-test areas, thereby effectively limiting the seepage area and ensuring the reliability of calculating the vertical permeability coefficient of the filter membrane of the sample 5. At the same time, the water-proof layer can guide the water flow through the filter membrane and seep from both sides of the drainage board core plate.

[0032] In a specific implementation, the first sealing gasket 401 and the second sealing gasket 402 can be configured as EPDM rubber sealing gaskets.

[0033] In a specific implementation, the permeation overflow chamber 3 is made of transparent plexiglass, which has good strength and facilitates observation of the entire test process.

[0034] In specific implementation methods, such as Figure 1 As shown, the water supply system is used to provide a stable water flow; specifically, the water supply system includes a water tank 20, a flow control valve 26, and an inlet pipe 19. The inlet end of the inlet pipe 19 is connected to the water tank 20, and the outlet end is connected to the permeation lower chamber 13. The flow control valve 26 is installed on the inlet pipe 19 to control the inlet flow rate. The height of the inlet of the inlet pipe 19 is higher than the height of the permeation overflow chamber 3.

[0035] In specific implementation methods, such as Figure 1As shown, the water supply system also includes a level gauge 21, a heating wire 22, and a condenser 23. The level gauge 21 is installed inside the water tank 20 to monitor the water level. The heating wire 22 is spirally wound inside the water tank 20, and the condenser 23 is located inside the water tank 20, spaced apart from the heating wire 22. The heating wire 22 and the condenser 23 are suitable for regulating the water temperature in the water tank 20 to a constant temperature. The introduction of the level gauge 21, heating wire 22, and condenser 23 ensures that the water supply system can provide a constant temperature water flow. Since the viscosity of water is very sensitive to temperature, temperature changes will directly cause fluctuations in the calculated permeability coefficient. By maintaining a stable water level with the level gauge 21, combined with the closed-loop temperature control of the heating wire 22 and the condenser 23, the test error caused by water temperature changes is eliminated. This design can improve the standardization of test conditions and the comparability of experimental results at different times and in different experiments, making the data more reasonable and accurate.

[0036] In specific implementation methods, such as Figure 1 As shown, the water pressure differential monitoring and control system includes an upstream pressure transmitter 151 and a downstream pressure transmitter 152. The upstream pressure transmitter 151 is connected to the lower permeation chamber 13, and the downstream pressure transmitter 152 is connected to the permeation overflow chamber 3. The permeate monitoring and control system includes a permeate collection chamber 8 and a collection pressure transmitter 14. The permeate collection chamber 8 is connected to the permeation overflow chamber 3 to collect overflow water, and the collection pressure transmitter 14 is located in the permeate collection chamber 8 to monitor pressure changes.

[0037] In specific implementation methods, such as Figure 1 and Figure 2 As shown, a pressure transmitter 14 is installed on each side of the permeate collection chamber 8 to provide real-time feedback on pressure changes within the permeate collection chamber 8 and to record the flow rate.

[0038] In a specific embodiment, the permeate collection chamber 8 is arranged around the periphery of the permeate overflow chamber 3, and the permeate collection chamber 8 is provided with a drain outlet 24, which is spaced apart from the collection pressure transmitter 14. The permeate collection chamber 8 is arranged around the periphery of the permeate overflow chamber 3 to form a water collection and metering space, ensuring that all water overflowing from the permeate overflow chamber 3 is completely collected, avoiding metering errors caused by local stagnation or splashing; the collection pressure transmitter 14 accurately calculates the flow rate by monitoring the pressure change caused by the rise in water level in this sealed collection chamber. Compared with traditional volume readings, it is more sensitive, easier to automate, and can reduce human reading errors.

[0039] The testing device provided in this embodiment enables in-situ composite testing of plastic drainage board filter membranes. Through the combination of the sample sealing system and the pressurization system, testing can be performed directly on the intact drainage board without peeling off the filter membrane, solving the problem of non-destructive testing due to thermal fusion bonding. The setting of the inlet pipe 19 above the permeate overflow chamber 3 in the water supply system ensures stable upstream water pressure. The combination of the water pressure difference monitoring system and the permeate water monitoring system enables automatic monitoring of head difference and flow rate. Calculations are then performed through the data processing module 18, improving the accuracy and efficiency of the test. The test results accurately reflect the permeation performance of the filter membrane under actual working conditions.

[0040] In specific implementation methods, such as Figure 1 As shown, the testing device also includes a base 1 and a support 2. The support 2 is fixedly mounted on the upper end of the base 1, and the permeation chamber 13 is installed on the upper end of the support 2. Several second tie rods 12 are provided on the support 2, and the pressurization system is installed on the second tie rods 12. Through the combination of the base 1, the support 2, and the second tie rods 12, a stable and rigid support frame can be established.

[0041] In specific implementation methods, such as Figure 1 As shown, the pressurization system includes a pressure regulating drive 11, a piston rod 10, and a first pull rod 9. The piston rod 10 is fixedly connected to the drive end of the pressure regulating drive 11, and the piston rod 10 is connected to the upper pressure cover 6 via the first pull rod 9. The pressure regulating drive 11 is adapted to drive the piston rod 10 to push the upper pressure cover 6 closer to the base 7 to apply pressure to the sample 5. The mounting end of the pressure regulating drive 11 is fixedly set with all the second pull rods 12. By mounting the pressure regulating drive 11 on the second pull rods 12 and placing the piston rod 10 and the first pull rod 9 inside it, the force distribution of the entire pressurization system is more reasonable, effectively reducing the vibration or off-center load that may occur during the test. This ensures that the device can maintain high stability and repeatability during long-term testing under different pressure conditions, providing a favorable structural basis for obtaining accurate and reproducible test results.

[0042] This embodiment, through the vertical transmission design of the pressure regulating drive component 11, piston rod 10, and first pull rod 9, can apply uniform, controllable, and vertically downward pressure to the sample, ensuring the stability and accuracy of pressure transmission. On the one hand, it ensures that the sample sealing system can effectively seal the non-test area and prevent water flow short circuits. On the other hand, it can simulate the real lateral pressure of soil on the drainage board, so that the filter membrane is in a stress state close to the actual engineering situation during testing, thereby improving the reliability of test data.

[0043] In a specific implementation, the pressure regulating drive 11 adopts a pneumatic loading working mode.

[0044] In a specific embodiment, the piston rod 10 and the first pull rod 9 are both vertically arranged, the second pull rod 12 is vertically arranged, and the piston rod 10 and the first pull rod 9 are located inside all the second pull rods 12.

[0045] In a further implementation, such as Figure 1 As shown, the water pressure difference measurement and control system also includes a pressure measuring tube 16 and a measuring element 17. The measuring element 17 is installed on the pressure measuring tube 16 to measure the water head height of the pressure measuring tube 16. The first pressure measuring end of the pressure measuring tube 16 is connected to the upstream pressure transmitter 151, and the second pressure measuring end is connected to the downstream pressure transmitter 152. The testing device can achieve automatic data acquisition through the upstream pressure transmitter 151, and also forms an independent measurement design through the pressure measuring tube 16 and the measuring element 17. By using the added measuring element 17 in conjunction with the pressure measuring tube 16, a more intuitive and reliable water head difference can be provided for manual observation and calibration. This design allows the operator to verify and calibrate the readings of the electronic sensor on-site at any time, and can promptly detect and correct any zero drift or error that may exist in the pressure transmitter, which helps to enhance the reliability of the water head difference parameter and the long-term measurement accuracy of the device.

[0046] In specific implementation methods, such as Figure 1 As shown, the water pressure differential measurement and control system also includes a first tee fitting 251 and a second tee fitting 252. The first tee fitting 251 is installed on the lower permeation chamber 13. The first interface of the first tee fitting 251 is connected to the lower permeation chamber 13, the second interface of the first tee fitting 251 is connected to the upstream pressure transmitter 151, and the third interface of the first tee fitting 251 is connected to the first pressure measuring end of the pressure measuring tube 16. The second tee fitting 252 is installed on the permeation overflow chamber 3. The first interface of the second tee fitting 252 is connected to the permeation overflow chamber 3, the second interface of the second tee fitting 252 is connected to the downstream pressure transmitter 152, and the third interface of the second tee fitting 252 is connected to the second pressure measuring end of the pressure measuring tube 16.

[0047] This scheme uses a first tee fitting 251 and a second tee fitting 252 for fluid connection, connecting the upstream pressure transmitter 151 and downstream pressure transmitter 152 (automatic measurement) and the two pressure measuring ends of the manually calibrated pressure measuring tube 16 to the lower permeation chamber 13 and the permeation overflow chamber 3 to achieve dynamic calibration. This connection method ensures that the two measurement systems measure the water pressure at the same location, providing a benchmark for data comparison and enabling convenient and reliable implementation of the device's calibration function.

[0048] The testing device provided in this embodiment adopts a composite in-situ testing mechanism. Under a set pressure, two sealing gaskets form a permeation channel for a single-sided filter membrane. The core plate grooves of the sample 5 are directly connected to the permeation overflow chamber 3, simulating the actual drainage path. It can simulate stress states; vertical pressure can simultaneously simulate lateral soil pressure, restoring the lateral soil pressure or partial stress conditions experienced by the drainage board in actual soil, thus placing the filter membrane in a compression state closer to actual conditions during testing. It features automatic data acquisition, specifically through a pressure transmitter, automatically acquiring head difference and seepage flow rate, reducing manual measurement errors; and real-time cross-calibration between the pressure transmitter and the pressure measuring tube 16 facilitates instrument verification and calibration, forming dynamic calibration.

[0049] According to an embodiment of the present invention, in another aspect, a testing method for a drainage board filter membrane vertical permeability coefficient testing device is also provided, comprising the following steps: Cut a sample piece of the specified size; The saturated sample 5 is installed on the base 7, and vertical pressure is applied by the pressurization system so that the upper cover 6 and the base 7 press together against the sample 5. Open the flow control valve 26 and inject constant temperature water into the permeation chamber 13 through the inlet pipe 19. Observe and remove air bubbles until the permeation overflow chamber 3 overflows. Adjust the flow control valve 26 to stabilize the head difference between upstream and downstream, start the data processing module 18 to collect data, start collecting infiltration water, and stop when the collected water volume reaches the preset condition. The data processing module 18 calculates the vertical permeability coefficient of the filter membrane in sample 5 based on the collected head difference, flow rate, and time.

[0050] This test method obtains the vertical permeability coefficient of the filter membrane of sample 5 through sample preparation, saturation, sealing, water injection and venting, and automatic testing and calculation. This method can ensure the consistency of the test process and the repeatability of the results, so that different operators and different times can obtain comparable data by following this method, so as to carry out standardized, non-destructive, and accurate in-situ determination of the vertical permeability coefficient of the filter membrane of sample 5.

[0051] In a specific implementation, during the permeation test, the head difference is manually observed through the pressure measuring tube 16 and measuring element 17 of the water pressure difference measurement and control system, and compared with the collected head difference data to calibrate the head difference.

[0052] While automating data acquisition, operators can manually compare the data using the pressure measuring tube 16 of the differential pressure measurement and control system to obtain original, more reliable head difference data. This allows for verification of data validity during testing and monitoring of sensor performance degradation during long-term use, helping to identify potential errors and ensuring the entire testing device has accurate measurement performance.

[0053] I. Preparations before the test 1. Sample preparation Sampling: Randomly cut a 100mm long sample piece 5 from the plastic drainage board product to be tested.

[0054] Inspection: Ensure that the surface of sample 5 is clean and free of dirt, oil stains and obvious damage.

[0055] Saturation: Place sample 5 in water containing a wetting agent (such as isopropanol to reduce the surface tension of water) and immerse it at laboratory standard temperature for at least 12 hours to ensure that the filter membrane is fully saturated.

[0056] 2. Equipment and Environmental Preparation Equipment Inspection: Check that all connecting pipes of the testing equipment are unobstructed and that the gaskets are intact and clean. Ensure that the pressurization system, all pressure transmitters, and data processing module 18 are functioning properly.

[0057] Preparation of constant temperature water: Turn on the heating wire 22 and condenser 23 of the constant temperature water supply tank 20 to set and stabilize the water temperature at the standard test temperature (e.g., 20±2°C).

[0058] II. Test Steps Step 1: Install and seal the sample piece 5 Remove the saturated sample 5 from the soaking solution and gently wipe away excess moisture from the surface with a damp cloth.

[0059] Place the sample 5 flat on the second sealing gasket 402 of the base 7, ensuring that it completely covers the permeation channel in the center of the base 7.

[0060] Start the pressurization system to move the upper pressure cover 6 downwards and into contact with the upper surface of the sample 5.

[0061] The vertical pressure was slowly increased to 100 kPa and kept stable. This pressure caused the upper and lower sealing gaskets to deform and tightly press against the non-tested areas of the drainage board filter membrane, forming an effective sealing and waterproof layer, while simulating soil pressure.

[0062] Step 2: System water filling and air venting Slowly open the flow control valve 26 to allow constant temperature water to be injected into the lower permeation chamber 13 from the bottom through the inlet pipe 19; Carefully observe whether air bubbles are generated in the permeation chamber 13, the contact surface between the sample 5 and the sealing gasket, and the connecting pipeline.

[0063] If there are air bubbles, gently tap the corresponding area to help them rise and escape.

[0064] Continue injecting water until it completely fills the lower permeation chamber 13 and passes through the filter membrane of the sample 5, seeping from both sides of the drainage plate core until it fills the entire permeation overflow chamber 3 and the overflow stabilizes. This indicates that the water flow channel is clear and most of the air in the system has been expelled.

[0065] Step 3: Stabilizing the head and calibration Adjust the flow control valve 26 and observe the readings of the upstream pressure transmitter 151 and the downstream pressure transmitter 152; so that a stable head difference Δh that meets the test requirements is formed between the upstream and downstream.

[0066] Calibration: Simultaneously read the water column height displayed in the pressure measuring tube 16 and perform manual measurement using the measuring element 17. Compare the measured manual head difference with the electronic head difference collected by the actual pressure transmitter. If there is a significant deviation, the pressure transmitter should be calibrated using the calibration program of the data processing system to ensure the accuracy of the data source.

[0067] Step 4: Conduct penetration testing After confirming that the head difference Δh is stable, close the drain outlet 24 of the infiltration water collection chamber 8.

[0068] In the data processing system's software interface, start the test program. The system will automatically start timing.

[0069] The permeate continues to pass through the filter membrane, flows into the permeate overflow chamber 3 through the grooves of the core plate, and then overflows into the peripheral permeate collection chamber 8.

[0070] The pressure transmitter 14 collects the pressure increase in the collection chamber due to the rise in water level in real time and converts it into seepage flow rate V.

[0071] The program automatically stops data acquisition when it determines that the collected water volume has reached 1000 mL or the infiltration time has reached 30 seconds.

[0072] Step 5: Post-test processing After the test, open the drain outlet 24 to drain the water from the infiltration water collection chamber 8.

[0073] Release the pressure of the pressurization system, loosen the upper pressure cap 6, and remove the sample piece 5.

[0074] Clean and wipe all parts of the device in preparation for future use.

[0075] III. Data Processing and Reporting The data processing module 18 will automatically record the head difference Δh (cm) and the infiltration volume V (cm). 3 Given the infiltration time t(s), substitute it into Darcy's law formula to calculate: k=(V×δ) / (A×t×Δh) Where, k: vertical permeability coefficient of the filter membrane (cm / s); V: total water volume passing through the filter membrane in time t (cm³ / s). 3 ); δ: Filter membrane thickness (cm), which needs to be measured separately using a thickness gauge before the test; A: Effective permeation area of ​​the filter membrane (cm²) 2 The area of ​​the permeation channel at the center of base 7 is determined by the area of ​​the channel (for example, for a channel with a diameter of 80 mm, A = π × (4)² ≈ 50.27 cm). 2 ); t: time (s) for the infiltration volume V; Δh: average head difference (cm) between upstream and downstream; Test report: The report should include at least the following information: sample information, test conditions (temperature, vertical pressure), parameters used in the calculation (A, δ), test results (k value), and any anomalies observed.

[0076] The testing apparatus and methods described above are applicable to the vertical permeability coefficient testing of various types of plastic drainage board filter membranes, including but not limited to hot-melt adhesive drainage boards.

[0077] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A device for testing the vertical permeability coefficient of a drainage board filter membrane, characterized in that, include: The sample sealing system includes a permeation overflow chamber (3), an upper pressure cap (6), and a base (7). The upper pressure cap (6) and the base (7) are disposed in the permeation overflow chamber (3). The upper pressure cap (6) and the base (7) are adapted to press together the sample piece (5). A permeation channel is provided through the center of the base (7), and a lower permeation chamber (13) is connected below the permeation channel. The pressurization system is adapted to apply vertical pressure to the upper pressure cap (6) so that the upper pressure cap (6) is close to the base (7) to pressurize the sample (5); The water supply system includes a water tank (20), a flow control valve (26), and an inlet pipe (19). The inlet end of the inlet pipe (19) is connected to the water tank (20), and the outlet end is connected to the permeation lower chamber (13). The flow control valve (26) is installed on the inlet pipe (19) to control the inlet flow rate. The height of the inlet of the inlet pipe (19) is higher than the height of the permeation overflow chamber (3). The water pressure differential measurement and control system includes an upstream pressure transmitter (151) and a downstream pressure transmitter (152). The upstream pressure transmitter (151) is connected to the lower permeation chamber (13), and the downstream pressure transmitter (152) is connected to the permeation overflow chamber (3). The permeate water monitoring and control system includes a permeate water collection chamber (8) and a collection pressure transmitter (14). The permeate water collection chamber (8) is connected to the permeate overflow chamber (3) to collect overflow water. The collection pressure transmitter (14) is located in the permeate water collection chamber (8) to monitor pressure changes. The data processing module (18) is connected to the water pressure difference measurement and control system and the permeate measurement and control system via the signal line (27), and is configured to acquire the head difference, flow rate and time parameters to calculate the vertical permeability coefficient of the filter membrane of the sample (5).

2. The vertical permeability coefficient testing device for drainage board filter membrane according to claim 1, characterized in that, The pressurization system includes a pressure regulating drive (11), a piston rod (10), and a first pull rod (9). The piston rod (10) is fixedly connected to the drive end of the pressure regulating drive (11). The piston rod (10) is connected to the upper pressure cover (6) through the first pull rod (9). The pressure regulating drive (11) is adapted to drive the piston rod (10) to push the upper pressure cover (6) closer to the base (7) to pressurize the sample (5). The piston rod (10) and the first pull rod (9) are both vertically arranged.

3. The vertical permeability coefficient testing device for drainage board filter membrane according to claim 2, characterized in that, It also includes a base (1) and a bracket (2), the bracket (2) is fixedly disposed on the upper end of the base (1), and the permeation chamber (13) is installed on the upper end of the bracket (2); the bracket (2) is provided with a plurality of second pull rods (12), and the mounting end of the pressure regulating drive (11) is fixedly disposed with all the second pull rods (12); the second pull rods (12) are vertically disposed, and the piston rod (10) and the first pull rod (9) are disposed on the inner side of all the second pull rods (12).

4. The vertical permeability coefficient testing device for drainage board filter membrane according to claim 1, characterized in that, The sample sealing system further includes a first sealing gasket (401) and a second sealing gasket (402). The first sealing gasket (401) is fixedly disposed on the side of the upper pressure cap (6) facing the base (7). A circular seepage channel is provided in the middle of the first sealing gasket (401). The radial dimension of the circular seepage channel is the same as the radial dimension of the seepage channel in the center of the base (7). The second sealing gasket (402) is fixedly disposed on the side of the base (7) facing the upper pressure cap (6).

5. The vertical permeability coefficient testing device for drainage board filter membrane according to claim 1, characterized in that, The water pressure differential measurement and control system also includes a pressure measuring tube (16) and a measuring element (17). The measuring element (17) is installed on the pressure measuring tube (16) to measure the water head height of the pressure measuring tube (16). The first pressure measuring end of the pressure measuring tube (16) is connected to the upstream pressure transmitter (151), and the second pressure measuring end is connected to the downstream pressure transmitter (152).

6. The vertical permeability coefficient testing device for drainage board filter membrane according to claim 5, characterized in that, The water pressure differential measurement and control system further includes a first tee (251) and a second tee (252). The first tee (251) is installed on the lower permeation chamber (13). The first interface of the first tee (251) is connected to the lower permeation chamber (13), the second interface of the first tee (251) is connected to the upstream pressure transmitter (151), and the third interface of the first tee (251) is connected to the first pressure measuring end of the pressure measuring tube (16). The second tee (252) is installed on the permeation overflow chamber (3). The first interface of the second tee (252) is connected to the permeation overflow chamber (3), the second interface of the second tee (252) is connected to the downstream pressure transmitter (152), and the third interface of the second tee (252) is connected to the second pressure measuring end of the pressure measuring tube (16).

7. The device for testing the vertical permeability coefficient of a drainage board filter membrane according to any one of claims 1-6, characterized in that, The water supply system also includes a level gauge (21), a heating wire (22), and a condenser (23); the level gauge (21) is installed in the water tank (20) to monitor the water level in the water tank (20); the heating wire (22) is spirally wound in the water tank (20); the condenser (23) is set in the water tank (20) and spaced apart from the heating wire (22); the heating wire (22) and the condenser (23) are adapted to regulate the water temperature in the water tank (20) to a constant temperature state.

8. The device for testing the vertical permeability coefficient of a drainage board filter membrane according to claim 1, characterized in that, The permeate collection chamber (8) is arranged around the periphery of the permeate overflow chamber (3), and the permeate collection chamber (8) is provided with a drain outlet (24), which is spaced apart from the collection pressure transmitter (14).

9. A test method for the vertical permeability coefficient testing device for drainage board filter membranes as described in any one of claims 1-8, characterized in that, Includes the following steps: Cut a sample piece of the specified size (5); The saturated sample (5) is installed on the base (7), and vertical pressure is applied by the pressurization system so that the upper pressure plate (6), the first sealing gasket (401), the base (7), and the second sealing gasket (402) press together against the sample (5); Open the flow control valve (26) and inject constant temperature water into the permeation chamber (13) through the water inlet pipe (19). Observe and remove air bubbles until the permeation overflow chamber (3) overflows. Adjust the flow control valve (26) to stabilize the head difference between upstream and downstream, start the data processing module (18) to collect data, start collecting infiltration water, and stop when the collected water volume reaches the preset condition; The data processing module (18) calculates the vertical permeability coefficient of the filter membrane of the sample (5) based on the collected head difference, flow rate and time.

10. The test method according to claim 9, characterized in that, In the permeation test, the head difference is manually observed through the pressure measuring tube (16) and measuring element (17) of the water pressure difference measurement and control system, and compared with the collected head difference data to calibrate the head difference.

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