A test apparatus and method for testing the permeability of a concrete panel

Abstract

The application belongs to the technical field of concrete permeability testing, and specifically provides a test device and method for testing the permeability of a concrete panel, a panel test piece bending and tension loading device for applying bending and tension load to the concrete panel test piece, a vacuum water saturation machine for vacuum water saturation of the concrete panel test piece, and a panel test piece resistance testing device for testing the resistance of the concrete panel test piece or for testing the resistance of the concrete panel test piece under the bending and tension load, solving the problem that the existing technology cannot accurately test the permeability of the concrete panel under the bending and tension load, and realizing nondestructive testing of the permeability of the concrete panel under the bending and tension load, which is simple, convenient and fast to operate.

Description

Technical Field

[0001] This invention belongs to the field of concrete permeability testing technology, specifically relating to a test device and method for testing the permeability of concrete panels. Background Technology

[0002] my country is seeing an increasing number of ultra-high dam projects, including the Shuibuya Dam (233m high), the Yulongkash Hydropower Project (229.5m high), the Dashixia Hydropower Project (247m high), and the Lianghekou Dam (295m high). The concrete panel is the main seepage barrier in a concrete-faced rockfill dam, and its permeability directly impacts the safety of the seepage control system. Under actual service conditions, the seepage resistance of the concrete panel changes, and when it fails to meet design requirements, it threatens the safety and stability of the dam. Therefore, accurately testing and evaluating the seepage resistance of concrete panels under actual service conditions is crucial. Currently, my country mainly uses the hydraulic pressure method and the chloride ion penetration method to evaluate concrete permeability. The tests use frustum and cylindrical specimens, and the specimens are not subjected to load during the testing process. Under actual service conditions, the concrete panels near the abutments and perimeter joints of high-faced concrete dams are often subjected to flexural tensile stress. This stress easily leads to cracks on the surface and inside the concrete panel, severely reducing its seepage resistance. Therefore, accurately testing the permeability of concrete panels under flexural loads is crucial for objectively evaluating the permeability resistance of panels and the safety and stability of panel dams under actual service conditions. However, no methods for testing the permeability of concrete panels under flexural loads have been reported.

[0003] Chinese patent document CN113310878A, published on August 27, 2021, discloses a concrete permeability testing device, including a test bench, a detachable mold mounted on the test bench, and a pressurized liquid pipeline leading to the mold near the ground. An inlet hole is located on the test bench corresponding to the pressurized liquid pipeline, and the pressurized liquid flowing through the inlet hole is a contrast agent. The document also discloses a concrete permeability testing method using the device. After testing, a contrast agent is used to longitudinally scan the sample step-by-step to obtain concrete pore permeability imaging data, applicable to all concrete permeability tests. However, this document cannot accurately test the permeability of concrete panels under bending tensile loads. Summary of the Invention

[0004] The present invention provides a test device and method for testing the permeability of concrete panels, aiming to overcome the problem in the prior art that the permeability of concrete panels under bending tensile loads cannot be accurately tested.

[0005] Therefore, the present invention provides a test apparatus for testing the permeability of concrete panels, including a panel specimen bending and tensile loading device, a vacuum saturation machine, and a panel specimen resistance testing device; the panel specimen bending and tensile loading device is used to apply bending and tensile loads to the concrete panel specimen; the vacuum saturation machine is used to vacuum saturate the concrete panel specimen; and the panel specimen resistance testing device is used to test the resistance of the concrete panel specimen or to test the resistance of the concrete panel specimen under bending and tensile loads.

[0006] Preferably, the panel specimen bending and tensile loading device includes a loading device and a stress testing device. The loading device includes a reaction frame, a mechanical jack, and an upper pressure plate. The stress testing device includes a load sensor, a strain gauge, and a data acquisition device. The mechanical jack, load sensor, and upper pressure plate are connected sequentially from top to bottom inside the reaction frame. The strain gauge is connected to the reaction frame. Both the load sensor and the strain gauge are electrically connected to the data acquisition device.

[0007] Preferably, the reaction frame includes an upper horizontal frame, a first vertical support, a second vertical support, a third vertical support, a fourth vertical support, and a lower horizontal frame. The upper and lower horizontal frames are arranged symmetrically from top to bottom. The front left end of the upper horizontal frame is connected to the front left end of the lower horizontal frame through the first vertical support. The front right end of the upper horizontal frame is connected to the front right end of the lower horizontal frame through the second vertical support. The rear left end of the upper horizontal frame is connected to the rear left end of the lower horizontal frame through the third vertical support. The rear right end of the upper horizontal frame is connected to the rear right end of the lower horizontal frame through the fourth vertical support.

[0008] Preferably, a boss is provided on the lower part of the upper cross frame, and the boss is connected to the top of the mechanical jack.

[0009] Preferably, the upper pressure plate further includes two first support rollers, and the reaction frame further includes two second support rollers. The two first support rollers are longitudinally connected to the lower part of the upper pressure plate with left and right symmetrical intervals. One second support roller is longitudinally connected between the first vertical support and the third vertical support, and the other second support roller is longitudinally connected between the second vertical support and the fourth vertical support. The two second support rollers are left and right symmetrical, and the two first support rollers are located above the two second support rollers.

[0010] Preferably, the panel specimen resistance testing device includes a positive test cell, a negative test cell, and an AC digital bridge, with the AC digital bridge electrically connected to the positive test cell and the negative test cell respectively.

[0011] Preferably, the positive electrode test cell includes a first test cell, a first copper electrode mesh plate, a first sealing gasket, and a first sealant. A hole is horizontally opened from the outside to the inside in the middle of one side of the first test cell. The first sealing gasket and the first copper electrode mesh plate are fitted into the hole from the outside to the inside. A first liquid injection hole and a first terminal are opened on the positive electrode test cell. The first liquid injection hole passes through the upper part of the first test cell and the upper part of the first sealing gasket in sequence and is connected to the first copper electrode mesh plate. The lower end of the first terminal passes through the upper part of the first test cell and the upper part of the first sealing gasket in sequence and is connected to the first copper electrode mesh plate. The upper end of the first terminal extends out of the first test cell. A salt solution is injected into the first liquid injection hole. The first terminal is electrically connected to an AC digital bridge.

[0012] Preferably, the negative electrode test cell includes a second test cell, a second copper electrode mesh plate, a second sealing gasket, and a second sealant. A second hole is horizontally opened from the outside to the inside in the middle of one side of the second test cell. The second sealing gasket and the second copper electrode mesh plate are fitted into the second hole from the outside to the inside. A second injection hole and a second terminal are opened on the negative electrode test cell. The second injection hole passes through the upper part of the second test cell and the upper part of the second sealing gasket in sequence and is connected to the second copper electrode mesh plate. The lower end of the second terminal passes through the upper part of the second test cell and the upper part of the second sealing gasket in sequence and is connected to the second copper electrode mesh plate. The upper end of the second terminal extends out of the second test cell. Salt solution is injected into the second injection hole. The second terminal is electrically connected to an AC digital bridge.

[0013] Preferably, the vacuum filling machine includes a housing, a vacuum filling cylinder, a power supply, an air extraction device, an inlet / outlet device, a cylinder cover, and an exhaust device. The cylinder cover is connected to the top of the vacuum filling cylinder. The vacuum filling cylinder, the power supply, and the air extraction device are all connected inside the housing, and the power supply and the air extraction device are located outside the vacuum filling cylinder. The power supply is electrically connected to the air extraction device. The air extraction end of the air extraction device is connected to the vacuum filling cylinder. One end of the air extraction device is connected to the lower end of the inlet / outlet device, and the other end of the air extraction device extends out of the housing.

[0014] A test method based on the aforementioned test apparatus for testing the permeability of concrete panels includes the following steps:

[0015] 1) Select concrete panels with multiple mix proportions, and use the same process to make concrete panel specimens and concrete frustum specimens for each mix proportion. Then, cure the concrete panel specimens and concrete frustum specimens of each mix proportion to the required age, and test the resistance of the concrete panel specimens of each mix proportion and the permeability coefficient of the concrete frustum specimens after curing. Through regression analysis, establish the relationship curve between the resistance and permeability coefficient of the concrete panel specimens. When testing the resistance of the concrete panel specimens of each mix proportion after curing, a panel specimen resistance testing device is used. Before the test, a vacuum saturation machine is used to vacuum saturate the cured concrete panel specimens.

[0016] 2) Based on the mix proportion of the concrete panel to be tested, prepare the concrete panel specimens to be tested and cure them to the required age. Use a vacuum saturation machine to vacuum saturate the cured concrete panel specimens to be tested. Use a panel specimen bending tension loading device to apply bending tension load to the vacuum saturated concrete panel specimens to be tested. At the same time as applying the bending tension load, use a panel specimen resistance testing device to test the resistance of the concrete panel specimens to be tested under the bending tension load.

[0017] 3) Based on the relationship curve between the resistance and permeability coefficient of the concrete panel specimen established in step 1) and the resistance of the concrete panel specimen to be tested in step 2), the permeability coefficient of the concrete panel specimen to be tested under bending tensile load is obtained.

[0018] The beneficial effects of this invention are:

[0019] 1. The test apparatus for testing the permeability of concrete panels provided by this invention includes a panel specimen bending and tensile loading device, a vacuum saturation machine, and a panel specimen resistance testing device. The panel specimen bending and tensile loading device is connected to the panel specimen resistance testing device. The panel specimen bending and tensile loading device is used to apply bending and tensile loads to the concrete panel specimen. The vacuum saturation machine is used to vacuum saturate the concrete panel specimen. The panel specimen resistance testing device is used to test the resistance of the concrete panel specimen or to test the resistance of the concrete panel specimen under bending and tensile loads. This achieves non-destructive testing of the permeability of concrete panels under bending and tensile loads, and is simple, convenient, and fast to operate.

[0020] 2. The test device for testing the permeability of concrete panels provided by this invention includes a panel specimen bending and tensile loading device comprising a loading device and a stress testing device. A mechanical jack applies a four-point bending load to the concrete panel specimen, subjecting it to a uniform bending moment to simulate the bending and tensile stress experienced by the panel under actual service conditions. By adjusting the pressure applied by the mechanical jack, the bending and tensile stress value of the concrete panel specimen can be changed. This loading device has high loading accuracy and the load can remain stable over a long period, enabling the application of different levels of bending and tensile stress to the concrete panel specimen. The stress testing device can test the pressure applied by the mechanical jack and the bending and tensile deformation of the concrete panel specimen in real time, verifying the magnitude and stability of the bending and tensile stress on the concrete panel specimen. Within the allowable range of the bending and tensile strength of the concrete panel specimen, the magnitude of the bending and tensile stress can be arbitrarily adjusted, thereby achieving the testing of the permeability of the concrete panel under different bending and tensile stress levels.

[0021] 3. The test method for testing the permeability of concrete panels provided by this invention obtains the permeability coefficient of the concrete panel specimen under bending tensile load based on the relationship curve between the resistance and permeability coefficient of the concrete panel specimen established in step 1) and the resistance of the concrete panel specimen to be tested in step 2). This method enables the testing of concrete panel permeability under bending tensile load, thus providing a more objective and accurate evaluation of the permeability of the panel in the bending tensile stress zone under actual service conditions. On the one hand, it can accurately assess the evolution law of the permeability of the concrete panel in the bending tensile stress zone, thereby achieving accurate understanding of the safety of the panel dam seepage prevention system and timely early warning of risks. On the other hand, it can obtain the influence and law of bending tensile stress on the permeability of concrete panels, thereby guiding the optimal design of concrete panels in the bending tensile stress zone. Attached Figure Description

[0022] The present invention will now be described in further detail with reference to the accompanying drawings;

[0023] Figure 1 This is the left structural view of the panel specimen bending and tensile loading device;

[0024] Figure 2 This is the main structural view of the bending and tensile loading device for the panel specimen;

[0025] Figure 3 This is a graph showing the stress stability of the loading device over time under bending tensile stress.

[0026] Figure 4 This is a top view of the structure of a vacuum saturation machine;

[0027] Figure 5 This is the main structural view of the vacuum saturation machine;

[0028] Figure 6A cross-sectional view of the panel specimen resistance testing device connected to a concrete panel specimen.

[0029] Figure 7 This is a cross-sectional view of the negative electrode test cell;

[0030] Figure 8 This is a longitudinal cross-sectional view of the injection hole of the positive electrode plate;

[0031] Figure 9 This is a graph showing the relationship between the electrical resistance and permeability coefficient of a concrete panel specimen;

[0032] Figure 10 This is a resistance test diagram of a concrete panel specimen under bending tensile stress.

[0033] Explanation of reference numerals in the attached drawings: 1. Reaction frame; 2. Mechanical jack; 3. Load sensor; 4. Upper pressure plate; 5. Concrete panel specimen; 6. First support roller; 7. Second support roller; 8. Positive electrode test tank; 9. Exhaust device; 10. Pressure gauge; 11. Strain gauge; 12. Housing; 13. Vacuum saturated cylinder; 14. Power supply; 15. Air extraction device; 16. Negative electrode test tank; 17. Inlet and outlet drainage device; 18. Cylinder cover; 1-1. Upper horizontal frame; 1-2. First vertical support; 1-3. Second vertical support; 1-4. Third vertical support; 1-5. Fourth vertical support; 1-6. Lower horizontal frame; 1-7. Boss; 1-11 1-12, 2-13, 1-61, 1-62, 2-63, 1-64, 1-65, 1-66, 1-67, 1-68, 1-69, 1-60, 1-61, 1-62, 1-63, 1-64, 1-65, 1-66, 1-67, 1-68, 1-69, 1-60 ...9, 1-60, 1-61, 1-62, 1-63, 1-64, 1-65, 1-66, 1-67, 1-68, 1-69, 1-60, Detailed Implementation

[0034] Example 1:

[0035] like Figure 1 , Figure 2 and Figure 10 As shown, a test apparatus for testing the permeability of a concrete panel includes a panel specimen bending and tensile loading device, a vacuum saturation machine, and a panel specimen resistance testing device. The panel specimen bending and tensile loading device is used to apply bending and tensile loads to the concrete panel specimen 5; the vacuum saturation machine is used to vacuum saturate the concrete panel specimen 5; and the panel specimen resistance testing device is used to test the resistance of the concrete panel specimen 5.

[0036] The test device for testing the permeability of concrete panels was used to achieve non-destructive testing of the permeability of concrete panels under bending and tensile loads. The operation is simple, convenient and fast.

[0037] Example 2:

[0038] Based on Example 1, the panel specimen bending and tensile loading device includes a loading device and a stress testing device. The loading device includes a reaction frame 1, a mechanical jack 2, and an upper pressure plate 4. The stress testing device includes a load sensor 3, a strain gauge 11, and a data acquisition device. The mechanical jack 2, the load sensor 3, and the upper pressure plate 4 are connected sequentially from top to bottom inside the frame of the reaction frame 1. The strain gauge 11 is connected to the reaction frame 1. Both the load sensor 3 and the strain gauge 11 are electrically connected to the data acquisition device.

[0039] In use, the concrete panel specimen 5 is placed on the reaction frame 1. The strain gauge 11 is removed from the frame 1 and connected to the underside of the concrete panel specimen 5. A mechanical jack is used to load the concrete panel specimen 5, subjecting it to a uniform bending moment to simulate the bending tensile stress experienced by the concrete panel under actual service conditions. By adjusting the pressure applied by the mechanical jack, the bending tensile stress value of the concrete panel specimen 5 can be changed. This loading device has high loading accuracy and can maintain a stable load over a long period, enabling the application of different levels of load to the concrete panel specimen 5. Bending tensile stress; the stress testing device collects the bending tensile stress and strain data of the concrete panel specimen 5 in real time through load sensor 3 and strain gauge 11, and transmits the collected data to the data acquisition device in real time. Based on the collected data, the applied pressure of the mechanical jack is adjusted, and the bending tensile deformation of the concrete panel specimen 5 is tested in real time. This verifies the magnitude and stability of the bending tensile stress on the concrete panel specimen 5, allowing for arbitrary adjustment of the bending tensile stress within the allowable range of the concrete panel specimen 5's bending tensile strength, thereby enabling the testing of the permeability of the concrete panel under different bending tensile stress levels. The data acquisition device is an existing device and will not be described in detail here; an imported Australian Datataker DT80 data acquisition instrument can be used.

[0040] The strain gauge 11 of this invention is connected to the bottom of the concrete panel specimen 5, and is an external strain gauge, which satisfies both measurement accuracy and economic practicality.

[0041] Preferably, the reaction frame 1 includes an upper horizontal frame 1-1, a first vertical support 1-2, a second vertical support 1-3, a third vertical support 1-4, a fourth vertical support 1-5, and a lower horizontal frame 1-6. The upper horizontal frame 1-1 and the lower horizontal frame 1-6 are arranged symmetrically from top to bottom. The front left end of the upper horizontal frame 1-1 is connected to the front left end of the lower horizontal frame 1-6 through the first vertical support 1-2. The front right end of the upper horizontal frame 1-1 is connected to the front right end of the lower horizontal frame 1-6 through the second vertical support 1-3. The rear left end of the upper horizontal frame 1-1 is connected to the rear left end of the lower horizontal frame 1-6 through the third vertical support 1-4. The rear right end of the upper horizontal frame 1-1 is connected to the rear right end of the lower horizontal frame 1-6 through the fourth vertical support 1-5.

[0042] The reaction frame 1 has a simple and stable structure, which can stably install the concrete panel specimen 5, the remaining parts of the panel specimen bending and tension loading device and the panel specimen resistance testing device together. It occupies little space and is stable in operation.

[0043] Preferably, a boss 1-7 is provided on the lower part of the upper cross frame 1-1, and the boss 1-7 is connected to the top of the mechanical jack 2.

[0044] The diameter of the boss is the same as the top size of the mechanical jack 2, which makes it easy to place the mechanical jack 2 in the center position.

[0045] Preferably, the upper pressure plate 4 further includes two first support rollers 6, and the reaction frame 1 further includes two second support rollers 7. The two first support rollers 6 are longitudinally connected to the lower part of the upper pressure plate 4 with symmetrical spacing. One second support roller 7 is longitudinally connected between the first vertical support 1-2 and the third vertical support 1-4, and the other second support roller 7 is longitudinally connected between the second vertical support 1-3 and the fourth vertical support 1-5. The two second support rollers 7 are symmetrical to each other, and the two first support rollers 6 are located above the two second support rollers 7.

[0046] In use, a concrete panel specimen 5 is connected between two first support rollers 6 and two second support rollers 7. The two first support rollers 6 and two second support rollers 7 form a four-point bending load. Under the four-point bending test conditions, the concrete panel specimen 5 is simplified into a simply supported beam. A pure bending segment is formed between the two first support rollers 6 of the concrete panel specimen 5, and the bending moment is evenly distributed. By adjusting the position between the two first support rollers 6, most of the panel specimen can be subjected to a uniform bending moment, thereby better simulating the bending tensile stress of the concrete panel under actual service conditions.

[0047] Preferably, the distance between the two first support rollers 6 is adjustable. Adjusting the distance between the two first support rollers 6 as needed allows most of the panel specimen to be subjected to a uniform bending moment, thereby better simulating the bending and tensile stresses experienced by the concrete panel under actual service conditions.

[0048] Preferably, the upper horizontal frame 1-1 includes a first upper horizontal plate 1-11, a second upper horizontal plate 1-12, and a plurality of first ribs 1-13. The first upper horizontal plate 1-11 and the second upper horizontal plate 1-12 are arranged symmetrically horizontally, and are connected by the plurality of first ribs 1-13, which are vertically connected at even intervals. The lower horizontal frame 1-6 includes a first lower horizontal plate 1-61 and a plurality of second ribs 1-62. The upper part of the first lower horizontal plate 1-61 is connected to a second support roller 7, and the lower part of the first lower horizontal plate 1-61 is vertically connected to the second ribs 1-62 at even intervals. The lower part of the second upper horizontal plate 1-12 is connected to a boss 1-7. The structure is simple and has high stability.

[0049] Preferably, the reaction frame 1 is welded from high-strength chrome-plated anti-corrosion steel plate, the upper pressure plate 4 is made of high-strength chrome-plated anti-corrosion steel plate, and the first support roller 6 and the second support roller 7 are both made of high-strength chrome-plated anti-corrosion support rollers.

[0050] Both the high-strength chrome-plated anti-corrosion steel plate and the high-strength chrome-plated anti-corrosion support rollers can ensure no deformation during loading, guaranteeing long-term stability of bending tensile loads; they are corrosion-resistant and do not easily rust when exposed to air or in contact with water-saturated concrete panel specimens. The loading device has sufficient rigidity to ensure long-term stability of bending tensile loads (e.g., Figure 3 (As shown).

[0051] The method of using the panel specimen bending and tensile loading device of the present invention is as follows:

[0052] A concrete panel specimen 5 is placed on top of two second support rollers 7, and then a pressure plate 4 is placed on top of the concrete panel specimen 5, connecting the two first support rollers 6 to the top of the concrete panel specimen 5. A mechanical jack applies a four-point load to the concrete panel specimen 5, subjecting it to a uniform bending moment to simulate the bending tensile stress of a concrete panel under actual service conditions. By adjusting the pressure applied by the mechanical jack, the bending tensile stress value of the concrete panel specimen 5 can be changed. This loading device has high loading accuracy and can maintain a stable load over a long period, enabling stable loading of the concrete panel specimen 5. Different levels of bending tensile stress are applied; the stress testing device collects the bending tensile data of the concrete panel specimen 5 in real time through the load sensor 3 and strain gauge 11, and transmits the collected data to the data acquisition device in real time. Based on the collected data, the pressure applied by the mechanical jack is adjusted, and the pressure applied by the mechanical jack and the bending tensile deformation of the concrete panel specimen 5 are tested in real time. The magnitude and stability of the bending tensile stress on the concrete panel specimen 5 are verified in real time, so that the magnitude of the bending tensile stress can be arbitrarily adjusted within the allowable range of the bending tensile strength of the concrete panel specimen 5, thereby realizing the test of the permeability of the concrete panel under different bending tensile stress levels.

[0053] Example 3:

[0054] like Figures 6-8 As shown, based on Embodiment 2, the panel specimen resistance testing device includes a positive test cell 8, a negative test cell 16, and an AC digital bridge, which is electrically connected to the positive test cell 8 and the negative test cell 16 respectively.

[0055] In use, the positive test cell 8 is connected to one end of the concrete panel specimen 5, and the negative test cell 16 is connected to the other end of the concrete panel specimen 5. An AC digital bridge is connected to both the positive and negative test cells 8 and 16 respectively, with the positive test cell 8 serving as the positive terminal and the negative test cell 16 as the negative terminal. At the start of the test, the resistance value of the AC digital bridge is read and recorded. The electrodes connect the concrete panel specimen 5 as a resistor to the AC digital bridge via connecting wires. The digital bridge can directly measure the resistance of the concrete panel specimen 5. The structure is simple, the operation is convenient, and the measurement is accurate.

[0056] Preferably, the positive electrode test cell 8 includes a first test cell 8-1, a first copper electrode mesh plate 8-2, a first sealing gasket 8-3, and a first sealant 8-4. A hole 8-5 is horizontally formed from the outside to the inside on one side of the center of the first test cell 8-1. The first sealing gasket 8-3 and the first copper electrode mesh plate 8-2 are fitted into the hole 8-5 from the outside to the inside. A first liquid injection hole 8-6 and a first terminal 8-7 are formed on the positive electrode test cell 8. The first liquid injection hole 8-6 passes through the first test cell sequentially. The upper part of 8-1 and the upper part of the first sealing gasket 8-3, and the first injection hole 8-6 are connected to the first copper electrode mesh plate 8-2. The lower end of the first terminal 8-7 passes through the upper part of the first test tank 8-1 and the upper part of the first sealing gasket 8-3 in sequence, and the lower end of the first terminal 8-7 is connected to the first copper electrode mesh plate 8-2. The upper end of the first terminal 8-7 extends out of the first test tank 8-1. Salt solution is injected into the first injection hole 8-6. The first terminal 8-7 is electrically connected to the AC digital bridge.

[0057] Preferably, the negative electrode test tank 16 includes a second test tank 16-1, a second copper electrode mesh plate 16-2, a second sealing gasket 16-3, and a second sealant 16-4. A second hole 16-5 is horizontally formed from the outside to the inside on one side of the middle of the second test tank 16-1. The second sealing gasket 16-3 and the second copper electrode mesh plate 16-2 are fitted into the second hole 16-5 from the outside to the inside. A second injection hole 16-6 and a second terminal block 16-7 are formed on the negative electrode test tank 16. The second injection hole 16-6 passes through the second test tank in sequence. The upper part of 16-1 and the upper part of the second sealing gasket 16-3, and the second injection hole 16-6 are connected to the second copper electrode mesh plate 16-2. The lower end of the second terminal 16-7 passes through the upper part of the second test tank 16-1 and the upper part of the second sealing gasket 16-3, and the lower end of the second terminal 16-7 is connected to the second copper electrode mesh plate 16-2. The upper end of the second terminal 16-7 extends out of the second test tank 16-1. Salt solution is injected into the second injection hole 16-6. The second terminal 16-7 is electrically connected to the AC digital bridge.

[0058] When testing the resistance of concrete panel specimen 5 or the resistance of concrete panel specimen 5 under bending and tensile load, the concrete panel specimen 5 to be tested is wiped dry to a surface-dry state. The specimen is then installed between the positive electrode test tank 8 and the negative electrode test tank 16 (i.e., one end of the concrete panel specimen 5 is connected to hole 8-5 and the concrete panel specimen 5 is located outside the first copper electrode mesh plate 8-2 and the first sealing gasket 8-3, with the first sealant 8-4 filling the space between the concrete panel specimen 5 and the first test tank 8-1; the other end of the concrete panel specimen 5 is connected to hole 16-5 and the concrete panel specimen 5 is located outside the second copper electrode mesh plate 16-2 and the second sealing gasket 16-3). The soil panel specimen 5 and the second test tank 16-1 are filled with a second sealant 16-4, and the concrete panel specimen 5 and the first test tank 8-1 are filled with a first sealant 8-4 until there is no leakage between the concrete panel specimen 5 and the first test tank 8-1. The positive electrode test tank 8 is connected to the salt solution through the first terminal 8-7, and the negative electrode test tank 16 is connected to the salt solution through the second terminal 16-7. The AC digital bridge applies AC voltage to both ends of the concrete panel specimen 5, forming a stable current inside the concrete.

[0059] The positive electrode test cell 8 uses the first copper electrode mesh plate 8-2 and salt solution, while the negative electrode test cell 16 uses the second copper electrode mesh plate 16-2 and salt solution. The conductivity is more stable. The salt solution is in full contact with the end face of the concrete panel specimen 5, and the contact area is constant, which ensures that the internal current of the concrete is stable under AC voltage. This ensures that the resistance test results are accurate and reliable after the panel specimen is connected to the AC digital bridge.

[0060] The first terminal 8-7 has two functions: first, to fix the first copper electrode mesh plate 8-2 immersed in the salt solution; and second, to connect the connecting wire, i.e., the conductor. The second terminal 16-7 has two functions: first, to fix the second copper electrode mesh plate 16-2 immersed in the salt solution; and second, to connect the connecting wire, i.e., the conductor.

[0061] Preferably, the second test groove 16-1 and the second sealing gasket 16-3, the second test groove 16-1 and the concrete panel specimen 5, the first test groove 8-1 and the first sealing gasket 8-3, and the first test groove 8-1 and the concrete panel specimen 5 are all fastened together by bolts; this is economical, practical, and easy to install and disassemble.

[0062] Preferably, there are multiple bolts, which are evenly distributed circumferentially along the first test groove 8-1 or the second test groove 16-1. This improves the stability of the connection seal.

[0063] Preferably, both the first sealing gasket 8-3 and the second sealing gasket 16-3 are rubber sealing gaskets. The rubber sealing gaskets mainly serve to stop water seepage, preventing salt solution from seeping out from the contact surface between the test tank and the concrete panel specimen 5, and also reduce the wear of the specimen on the side wall of the test tank.

[0064] Preferably, the salt solution is a 3% NaCl solution. A 3% NaCl solution meets the requirements for conductivity and has low corrosiveness.

[0065] Preferably, the first copper electrode mesh plate 8-2 and the second copper electrode mesh plate 16-2 are perforated copper plates with dimensions of 80mm*155mm and a thickness of 0.50±0.05mm. The mesh diameter of the perforated copper plate is 0.95mm±0.09mm. This ensures the conductivity of the electrodes.

[0066] Preferably, the AC digital bridge is electrically connected to the first terminal 8-7 and the second terminal 16-7 via connecting wires. The connecting wires are copper wires with a diameter greater than 0.3mm. This meets the requirements for the test current carrying capacity and is not easily broken.

[0067] Preferably, both the first test tank 8-1 and the second test tank 16-1 are made of rigid plexiglass. They are corrosion-resistant and have the rigidity required for use.

[0068] The method of using the panel specimen resistance testing device of the present invention is as follows:

[0069] The concrete panel specimen 5 is connected between the positive test tank 8 and the negative test tank 16. The AC digital bridge is connected to the first terminal 8-7 and the second terminal 16-7 through electrodes. The positive test tank 8 is used as the positive electrode and the negative test tank 16 is used as the negative electrode. Salt solution is injected into the first injection hole 8-6 and the second injection hole 16-6 respectively. The resistance value of the AC digital bridge is read and recorded at the start of the test. The concrete panel specimen 5 is connected to the AC digital bridge as a resistor through the connecting wire. The digital bridge can directly test the resistance of the concrete panel specimen 5.

[0070] Example 4:

[0071] like Figure 4 and Figure 5 As shown, based on Embodiment 3, the vacuum filling machine includes a housing 12, a vacuum filling cylinder 13, a power supply 14, an air extraction device 15, an inlet / outlet device 17, a cylinder cover 18, and an exhaust device 9. The cylinder cover 18 is connected to the top of the vacuum filling cylinder 13. The vacuum filling cylinder 13, the power supply 14, and the air extraction device 15 are all connected inside the housing 12, and the power supply 14 and the air extraction device 15 are located outside the cylinder of the vacuum filling cylinder 13. The power supply 14 is electrically connected to the air extraction device 15. The air extraction end of the air extraction device 15 is connected to the vacuum filling cylinder 13. One end of the air extraction device 15 is connected to the lower end of the inlet / outlet device 17, and the other end of the air extraction device 15 extends out of the housing 12.

[0072] Power supply 14 supplies power to vacuum pumping device 15, which is used to extract the air pressure in vacuum saturated cylinder 13 to the target air pressure; inlet and outlet device 17 facilitates water inlet and outlet in vacuum saturated cylinder 13; exhaust device 9 facilitates pressure release in vacuum saturated cylinder 13.

[0073] The method of using the vacuum saturation machine of the present invention is as follows:

[0074] When conducting the vacuum saturation test, the concrete panel specimen 5 is placed in the vacuum saturation cylinder 13, and distilled water is injected into the vacuum saturation cylinder 13. The air extraction device 15 can make the air pressure in the vacuum saturation cylinder 13 reach the experimental requirements, and the water enters the interior of the concrete panel specimen 5 under negative pressure and is maintained until it reaches saturation.

[0075] Preferably, a pressure gauge 10 is connected to the top of the cylinder cover 18. The pressure gauge 10 facilitates the detection of the air pressure inside the vacuum saturated cylinder 13.

[0076] Preferably, the inlet and outlet device 17 includes an inlet valve, an outlet valve, an inlet pipe, and an outlet pipe. One end of the vacuum filling cylinder 13 is connected to the inlet pipe via the inlet valve, and the other end of the vacuum filling cylinder 13 is connected to the outlet pipe via the outlet valve. The structure is simple and the inlet and outlet are convenient.

[0077] Preferably, a first sealing gasket 13-1 is provided between the vacuum filling cylinder 13 and the cylinder cover 18 to ensure the airtightness of the vacuum filling cylinder 13.

[0078] Preferably, a second sealing element is provided at the connection between the vacuum filling cylinder 13 and the inlet / outlet device 17 to ensure that the connection can be sealed.

[0079] Preferably, the vacuum saturation cylinder 13 is made of stainless steel. Stainless steel has good corrosion resistance.

[0080] Example 5:

[0081] A test method based on the aforementioned test apparatus for testing the permeability of concrete panels includes the following steps:

[0082] 1) Select concrete panels with multiple mix proportions, and use the same process to make concrete panel specimens and concrete frustum specimens for each mix proportion. Then, cure the concrete panel specimens and concrete frustum specimens of each mix proportion to the required age, and test the resistance of the concrete panel specimens of each mix proportion and the permeability coefficient of the concrete frustum specimens after curing. Through regression analysis, establish the relationship curve between the resistance of the concrete panel specimens and the permeability coefficient. When testing the resistance of the concrete panel specimens of each mix proportion after curing, a panel specimen resistance testing device is used. Before the test, a vacuum saturation machine is used to vacuum saturate the cured concrete panel specimens.

[0083] 2) Based on the mix proportion of the concrete panel to be tested, prepare the concrete panel specimens to be tested and cure them to the required age. Use a vacuum saturation machine to vacuum saturate the cured concrete panel specimens to be tested. Use a panel specimen bending tension loading device to apply bending tension load to the vacuum saturated concrete panel specimens to be tested. At the same time as applying the bending tension load, use a panel specimen resistance testing device to test the resistance of the concrete panel specimens to be tested under the bending tension load.

[0084] 3) Based on the relationship curve between the resistance and permeability coefficient of the concrete panel specimen established in step 1, and the resistance of the concrete panel specimen to be tested in step 2, the permeability coefficient of the concrete panel specimen to be tested under bending tensile load is obtained.

[0085] This experimental method can test the permeability of concrete panels under flexural loads, thus providing a more objective and accurate evaluation of the permeability of panels in areas subjected to flexural stress under actual service conditions. On the one hand, it can accurately assess the evolution of permeability of concrete panels in areas subjected to flexural stress, thereby enabling accurate understanding of the safety of the anti-seepage system of panel dams and timely early warning of risks. On the other hand, it can obtain the influence and influence law of flexural stress on the permeability of concrete panels, thereby guiding the optimal design of concrete panels in areas subjected to flexural stress.

[0086] Example 6:

[0087] A test method based on the aforementioned test apparatus for testing the permeability of concrete panels includes the following steps:

[0088] 1) Establish the relationship curve between the resistivity and permeability coefficient of concrete panel specimens;

[0089] Five concrete panel mix proportions were selected, and each of the five mix proportions was used to make concrete panel specimens with dimensions of 550mm*150mm*75mm and concrete frustum specimens. The dimensions were in accordance with the requirements of "Relative Permeability Test of Concrete" in SL / T 352-2020. After demolding, the specimens were cured to the required age according to standard.

[0090] The resistivity of concrete panel specimens and the permeability coefficient of concrete frustum specimens were tested at curing ages of 3d, 7d, 14d, 28d, 56d, and 90d. The resistivity of concrete panel specimens was tested using the aforementioned panel specimen resistivity testing device. Before testing, the concrete panel specimens were vacuumed for 3 hours and then saturated with water for 18 hours using a vacuum saturation machine. The permeability coefficient of the concrete frustum specimens was determined according to the requirements of "Relative Permeability Test of Concrete" in SL / T 352-2020.

[0091] The relationship curve between the resistivity and permeability coefficient of the concrete panel specimens was established through regression analysis, as shown in the attached figure. Figure 9 Where y is the permeability coefficient of the panel specimen, x is the resistance of the panel specimen, and R is the electrical resistance of the panel specimen. 2 It is the coefficient of determination

[0092] 2) Resistance test of concrete panel specimens under bending and tensile load

[0093] Based on the mix proportions of the concrete panel to be tested, concrete panel specimens with dimensions of 550mm*150mm*75mm were prepared. After curing under standard conditions for 28 days, the concrete panel specimens were then vacuum-sealed for 3 hours and saturated with water for 18 hours using a vacuum saturation machine.

[0094] The aforementioned panel specimen bending tension loading device was used to apply a bending tension load to the saturated concrete panel specimen. Simultaneously, a panel specimen resistance testing device was used to test the resistance of the concrete panel specimen under the bending tension load. (See attached diagram.) Figure 10 .

[0095] 3) Estimation of permeability coefficient of concrete panel specimens under bending and tensile loads

[0096] By substituting the resistance of the concrete panel specimens tested in step 2 into the corresponding formula in step 1 using the resistance-permeability coefficient relationship curve established in step 1, the permeability coefficient of the concrete panel specimens under bending tensile load is calculated.

[0097] This invention enables non-destructive testing of the permeability of concrete panels under bending tensile loads. The operation is simple, convenient, and fast, providing technical support for the safety assessment of concrete panel dam seepage prevention systems under actual service conditions.

[0098] In the description of this invention, it should be understood that if terms such as "upper," "inner," or "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting the invention.

[0099] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A test method for a test apparatus for testing the permeability of concrete panels, characterized in that: Includes the following steps: 1) Select concrete panels with multiple mix proportions, and use the same process to make concrete panel specimens and concrete frustum specimens for each mix proportion. Then, cure the concrete panel specimens and concrete frustum specimens of each mix proportion to the required age, and test the resistance of the concrete panel specimens of each mix proportion and the permeability coefficient of the concrete frustum specimens after curing. Through regression analysis, establish the relationship curve between the resistance of the concrete panel specimens and the permeability coefficient. When testing the resistance of the concrete panel specimens of each mix proportion after curing, a panel specimen resistance testing device is used. Before the test, a vacuum saturation machine is used to vacuum saturate the cured concrete panel specimens. 2) Based on the mix proportion of the concrete panel to be tested, prepare the concrete panel specimens to be tested and cure them to the required age. Use a vacuum saturation machine to vacuum saturate the cured concrete panel specimens to be tested. Use a panel specimen bending tension loading device to apply bending tension load to the vacuum saturated concrete panel specimens to be tested. At the same time as applying the bending tension load, use a panel specimen resistance testing device to test the resistance of the concrete panel specimens to be tested under the bending tension load. 3) Based on the relationship curve between the resistance and permeability coefficient of the concrete panel specimen established in step 1) and the resistance of the concrete panel specimen to be tested in step 2), the permeability coefficient of the concrete panel specimen to be tested under bending tensile load is obtained. The test apparatus for testing the permeability of concrete panels includes a panel specimen bending load device, a vacuum saturation machine, and a panel specimen resistance test device; the panel specimen bending load device is used to apply bending load to the concrete panel specimen (5); the vacuum saturation machine is used to vacuum saturate the concrete panel specimen (5); the panel specimen resistance test device is used to test the resistance of the concrete panel specimen (5) or to test the resistance of the concrete panel specimen (5) under bending load; the vacuum saturation machine includes a shell (12), a vacuum saturation cylinder (13), a power supply (14), an air extraction device (15), an inlet and outlet drainage device (17), and a cylinder cover (18). 18) and exhaust device (9), the cylinder cover (18) is connected to the top of the vacuum filling cylinder (13), the vacuum filling cylinder (13), the power supply (14) and the air extraction device (15) are all connected inside the shell (12) and the power supply (14) and the air extraction device (15) are located outside the cylinder of the vacuum filling cylinder (13), the power supply (14) is electrically connected to the air extraction device (15), the air extraction end of the air extraction device (15) is connected to the vacuum filling cylinder (13), one end of the air extraction device (15) is connected to the lower end of the inlet and outlet device (17), and the other end of the air extraction device (15) passes through the shell (12); a pressure gauge (10) is provided on the top of the cylinder cover (18).

2. The test method of the test apparatus for testing the permeability of concrete panels as described in claim 1, characterized in that: The panel specimen bending and tension loading device includes a loading device and a stress testing device. The loading device includes a reaction frame (1), a mechanical jack (2) and an upper pressure plate (4). The stress testing device includes a load sensor (3), a strain gauge (11) and a data acquisition device. The mechanical jack (2), the load sensor (3) and the upper pressure plate (4) are connected sequentially from top to bottom inside the frame of the reaction frame (1). The strain gauge (11) is connected to the reaction frame (1). The load sensor (3) and the strain gauge (11) are both electrically connected to the data acquisition device.

3. The test method of the test apparatus for testing the permeability of concrete panels as described in claim 2, characterized in that: The reaction frame (1) includes an upper horizontal frame (1-1), a first vertical support (1-2), a second vertical support (1-3), a third vertical support (1-4), a fourth vertical support (1-5), and a lower horizontal frame (1-6). The upper horizontal frame (1-1) and the lower horizontal frame (1-6) are arranged symmetrically from top to bottom. The front left end of the upper horizontal frame (1-1) is connected to the front left end of the lower horizontal frame (1-6) through the first vertical support (1-2). The front right end of the upper horizontal frame (1-1) is connected to the front right end of the lower horizontal frame (1-6) through the second vertical support (1-3). The rear left end of the upper horizontal frame (1-1) is connected to the rear left end of the lower horizontal frame (1-6) through the third vertical support (1-4). The rear right end of the upper horizontal frame (1-1) is connected to the rear right end of the lower horizontal frame (1-6) through the fourth vertical support (1-5).

4. The test method of the test apparatus for testing the permeability of concrete panels as described in claim 3, characterized in that: A boss (1-7) is provided on the lower part of the upper cross frame (1-1), and the boss (1-7) is connected to the top of the mechanical jack (2).

5. The test method of the test apparatus for testing the permeability of concrete panels as described in claim 3, characterized in that: The upper pressure plate (4) also includes two first support rollers (6), and the reaction frame (1) also includes two second support rollers (7). The two first support rollers (6) are longitudinally connected to the lower part of the upper pressure plate (4) with left and right symmetrical intervals. One second support roller (7) is longitudinally connected between the first vertical support (1-2) and the third vertical support (1-4). The other second support roller (7) is longitudinally connected between the second vertical support (1-3) and the fourth vertical support (1-5). The two second support rollers (7) are symmetrical to each other. The two first support rollers (6) are located above the two second support rollers (7).

6. The test method of the test apparatus for testing the permeability of concrete panels as described in claim 1, characterized in that: The panel specimen resistance testing device includes a positive test cell (8), a negative test cell (16), and an AC digital bridge, which are electrically connected to the positive test cell (8) and the negative test cell (16), respectively.

7. The test method of the test apparatus for testing the permeability of concrete panels as described in claim 6, characterized in that: The positive electrode test tank (8) includes a first test tank (8-1), a first copper electrode mesh plate (8-2), a first sealing gasket (8-3), and a first sealant (8-4). A hole (8-5) is horizontally opened from the outside to the inside on one side of the middle of the first test tank (8-1). The first sealing gasket (8-3) and the first copper electrode mesh plate (8-2) are fitted into the hole (8-5) from the outside to the inside. A first liquid injection hole (8-6) and a first terminal (8-7) are opened on the positive electrode test tank (8). The first liquid injection hole (8-6) passes through the first test tank in sequence. The upper part of the first test tank (8-1) and the upper part of the first sealing gasket (8-3) are connected to the first copper electrode mesh plate (8-2). The lower end of the first terminal (8-7) passes through the upper part of the first test tank (8-1) and the upper part of the first sealing gasket (8-3) in sequence, and the lower end of the first terminal (8-7) is connected to the first copper electrode mesh plate (8-2). The upper end of the first terminal (8-7) passes out of the first test tank (8-1). Salt solution is injected into the first injection hole (8-6). The first terminal (8-7) is electrically connected to the AC digital bridge.

8. The test method of the test apparatus for testing the permeability of concrete panels as described in claim 6, characterized in that: The negative electrode test tank (16) includes a second test tank (16-1), a second copper electrode mesh plate (16-2), a second sealing gasket (16-3), and a second sealant (16-4). A second hole (16-5) is horizontally opened from the outside to the inside in the middle of one side of the second test tank (16-1). The second sealing gasket (16-3) and the second copper electrode mesh plate (16-2) are fitted into the second hole (16-5) from the outside to the inside. A second injection hole (16-6) and a second terminal (16-7) are opened on the negative electrode test tank (16). The second injection hole (16-6) passes through the second test tank in sequence. The upper part of the second test tank (16-1) and the upper part of the second sealing gasket (16-3) are connected to the second copper electrode mesh plate (16-2). The lower end of the second terminal (16-7) passes through the upper part of the second test tank (16-1) and the upper part of the second sealing gasket (16-3) in sequence. The lower end of the second terminal (16-7) is connected to the second copper electrode mesh plate (16-2). The upper end of the second terminal (16-7) passes out of the second test tank (16-1). Salt solution is injected into the second injection hole (16-6). The second terminal (16-7) is electrically connected to the AC digital bridge.

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