A prestressed vertical duct grouting pressure water seepage test device and test method

Abstract

The present invention discloses a prestressed vertical duct grouting pressure seepage test device and test method, wherein the experimental device includes a grouting device, a pressurizing device and a columnar pressure vessel; the pressure vessel includes a closed cylinder and a grouting port, an exhaust port and a seepage discharge port arranged on the closed cylinder; valves and pressure gauges are respectively arranged at the grouting port and the exhaust port; the pressurizing device can inflate and pressurize the columnar pressure vessel through the exhaust port; the grouting device grouts the columnar pressure vessel through the grouting port. The prestressed vertical grouting pressure seepage test device and test method of the present invention can accurately simulate the pressure seepage situation during on-site vertical grouting, so that relevant data can be obtained in advance during formal grouting, effectively reducing the unforeseen pressure seepage situation during formal grouting.

Description

Technical field:

[0001] The invention relates to a prestressed vertical grouting pressure water seepage test device, belonging to the technical field of building engineering construction, and more specifically, to a prestressed construction technology. Background technology:

[0002] Prestressed cement slurry contains bound water and free water. When the slurry is subjected to a certain pressure, a large amount of free water in the cement slurry will precipitate, which is called "bleeding". For example, in the construction of large-scale LNG storage tanks with bonded post-tensioning prestressing, when the height of the prestressed vertical channel is above 50m, the slurry is subjected to huge pressure during the grouting process and produces a large amount of bleeding. Therefore, before the formal grouting, the slurry needs to be tested for bleeding to understand the bleeding of the slurry, thereby improving the slurry performance or improving the grouting process. At present, the slurry pressure bleeding devices sold and used on the market can only test the pressure bleeding of pure slurry in a static state, and cannot simulate the bleeding of slurry in a dynamic state and under prestressed steel strands in actual grouting. Summary of the invention:

[0003] The purpose of the present invention is to provide a test device and a test method which can simulate the grout pressure seepage situation in the actual grouting of a prestressed vertical channel.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A prestressed vertical grouting pressure seepage test device, characterized in that it includes a grouting device, a pressurizing device and a columnar pressure vessel; the pressure vessel includes a closed cylinder and a slurry inlet, an exhaust port and a seepage outlet arranged on the closed cylinder; valves and pressure gauges are respectively arranged at the slurry inlet and the exhaust port; the pressurizing device can inflate and pressurize the columnar pressure vessel through the exhaust port; the grouting device grouts the columnar pressure vessel through the slurry inlet.

[0006] The closed cylinder is composed of a cylinder and a cover plate arranged on the upper end of the cylinder; the exhaust port is arranged on the cover plate.

[0007] A steel strand is arranged in the cylinder.

[0008] The cover plate is welded by a carbon steel disc and a steel pipe. A hole having the same size as the outer diameter of the steel pipe is provided in the center of the disc, and bolt holes are provided around the disc. The pressure gauge and the ball valve are connected to the steel pipe in sequence.

[0009] A carbon steel flange is welded on the top of the cylinder, bolt holes are arranged around it and carbon steel stiffening ribs are added; the cylinder is fixed with the carbon steel disc bolts of the cover plate through the carbon steel flange.

[0010] The seepage water outlet is connected to a steel pipe and a ball valve.

[0011] The grouting device uses a grouting pump for grouting; and the pressurizing device uses an air compressor for pressurizing.

[0012] A prestressed vertical grouting pressure seepage test method, characterized in that the steps are:

[0013] Step 1: Connect the pressurizing device to the exhaust port of the columnar pressure vessel, close the water seepage observation hole and the slurry inlet valve, open the exhaust port valve on the top of the cover plate, and proceed to the next step after the air tightness inspection is qualified;

[0014] Step 2: Close the exhaust port valve on the top of the cover plate and open the slurry inlet valve;

[0015] Step 3: The grout inlet is connected to the grouting device, and grouting begins in the cylindrical pressure vessel;

[0016] Step 4: Observe the pressure gauges at the slurry inlet and the top of the cover plate. When the pressure value of the top pressure gauge reaches the required pressure, stop grouting and close the slurry inlet valve. The pressure gauge at the slurry inlet is used to calibrate the pressure value of the top pressure gauge.

[0017] Step 5: Let it stand, and observe the top pressure gauge every 15-30 minutes. If there is pressure loss, use a pressure booster to replenish the pressure.

[0018] Step 6: After the specified time, open the ball valve on the top of the cover to release the pressure. After the pressure is released, open the water seepage observation hole and record the slurry water seepage height and amount.

[0019] Also includes:

[0020] Step 7: Adjust the pressure or standing time and repeat the above steps to obtain multiple sets of slurry seepage height and seepage amount data.

[0021] The pressure value of the top pressure gauge is calibrated by the difference between the pressure value of the slurry inlet pressure gauge and the pressure value of the top pressure gauge. The pressure value of the slurry inlet pressure gauge is 0.8-1.2 bar higher than the pressure value of the top pressure gauge.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The invention discloses a vertical channel grouting pressure seepage test device and test method, which achieves the required pressure by compressing air in the slurry itself, and simulates the gradual pressurization state of the slurry in the flow during the actual grouting process, which is more consistent with the actual working conditions.

[0024] Compared with the test device on the market that pressurizes the upper part to a certain pressure and then squeezes out water from the bottom in a static state, by using the prestressed vertical channel grouting pressure seepage test device of the present invention, the slurry naturally precipitates from the top of the pipe when the slurry is gradually rising and pressurized. The similarity between the seepage of the slurry and the seepage produced by the actual grouting reaches more than 90%, the test effect is obvious, and the accuracy of the test is greatly improved.

[0025] Practice has proved that after many tests and combined with the on-site formal grouting situation, the device and test method of the present invention have the following advantages:

[0026] It can simulate the actual grouting conditions on site, adding a dynamic grouting process from the previous single pressure seepage test, and can simulate the effect of steel strands on grout seepage, which fits the actual situation and makes the test more convincing;

[0027] No additional pressurizing equipment is required. The test can reach the required pressure by utilizing the grouting pump's own pumping pressure combined with the principle of compressed air.

[0028] In summary, by using a prestressed vertical grouting pressure seepage test device and test method of the present invention, the pressure seepage situation during on-site vertical grouting can be accurately simulated, so that relevant data can be obtained in advance during formal grouting, effectively reducing the unforeseen pressure seepage situation during formal grouting. Description of the drawings:

[0029] Figure 1 It is the overall schematic diagram of the prestressed vertical grouting pressure seepage test device;

[0030] Figure 2 It is a schematic diagram of the pressure vessel of the prestressed vertical grouting pressure seepage test device;

[0031] Figure 3 Schematic diagram of the pressure vessel cover of the prestressed vertical grouting pressure seepage test device.

[0032] Among them: 11. Pressure vessel; 12. Grouting pump; 13. Air compressor; 21. Cover plate; 22. Cylinder; 23. Pressure gauge; 24. Water seepage observation hole; 25. Ball valve; 26. Slurry inlet. Specific implementation method:

[0033] Embodiment 1:

[0034] like Figure 1-Figure 3 The prestressed vertical grouting pressure seepage test device of the present invention comprises a pressure vessel 11, a grouting pump and accessories 12, and an air compressor and accessories 13.

[0035] The pressure vessel 11 includes a cover plate 21 , a pressure vessel body 22 , a pressure gauge 23 and a ball valve 25 .

[0036] The cover plate 21 is welded by a disc 31 and a steel pipe 33; wherein the disc 31 is a 20 mm thick 235B carbon steel plate. A hole is opened in the center of the disc 31, and four bolt holes are opened around it. The steel pipe 33 is connected to the interior of the pressure vessel cylinder 22 through the center hole on the disc 31, and the pressure gauge 23 and the ball valve 25 are connected to the steel pipe 33 in sequence.

[0037] A flange 32 is welded on the top of the pressure vessel cylinder 21, and the flange 32 is made of 10mm thick 235B carbon steel. Four bolt holes are opened around the flange 32, and four 10mm thick 235B carbon steel stiffening ribs 34 are added; three seepage observation holes 24 are opened on the upper part of the cylinder 21, which are connected by steel pipes and connected to ball valves 25; a slurry inlet 26 is opened at the bottom of the cylinder 21, which is connected by steel pipes and connected to ball valves 25 and pressure gauges 23.

[0038] Embodiment 2:

[0039] A prestressed vertical grouting pressure water seepage test method of the present invention comprises the following steps:

[0040] Step 1: Secure the 6m high pressure vessel and set up a warning area;

[0041] Step 2: Insert 54 steel strands into the pressure vessel cylinder, cover it with a cover plate, and tighten it with M16 high-strength bolts;

[0042] Step 3: Connect the exhaust port to the air compressor, close all three upper water seepage observation holes and one lower slurry inlet valve, open the exhaust port valve on the top of the cover plate, and check the air tightness. After the pressure drop does not exceed 0.1 bar in 30 seconds, proceed to the next step;

[0043] Step 4: Close the exhaust port valve on the top of the cover plate and open the slurry inlet valve;

[0044] Step 5: Connect the slurry inlet to the grouting pump and start grouting using a slurry with a water-cement ratio of 0.313:1.

[0045] Step 6: Observe the pressure gauges at the slurry inlet and the top of the cover plate. Stop grouting when the pressure reaches 5 bar, and close the slurry inlet valve and the grouting pump.

[0046] Step 7: Let it stand for 1 hour and observe the top pressure gauge. If there is pressure loss, use an air compressor to replenish the pressure.

[0047] Step 8: After 15 minutes, open the ball valve on the top of the cover to release the pressure. After the pressure is released, open the water seepage observation hole to measure the water seepage height or amount of the slurry.

[0048] Step 9: Repeat the above steps by adjusting the pressure or the resting time to obtain multiple sets of data.

[0049] The following is some test data:

[0050]

[0051] The slurry water seepage rate measured by the test device on the market is below 5%.

[0052] Actual grouting seepage in the project:

[0053] V1 has a seepage length of 8.4m, a grouting length of 66.9m, and a seepage rate of approximately 12.6%;

[0054] The V2 seepage length is 10.0m, the grouting length is 66.9m, and the seepage rate is about 14.9%.

[0055] Affected by factors such as ambient temperature, slurry fluidity, and slurry temperature, the water seepage rate will vary to a certain extent. The average values ​​of the actual grouting water seepage rates of two times are taken for comparison:

[0056] The average water seepage rate is: (V1+V2) / 2=(12.6%+14.9%) / 2=13.75%

[0057] The water seepage rate measured by the device of the present invention is: 705÷5645×100%=12.5%

[0058] Similarity rate = 1-(|experimental water seepage rate-actual water seepage rate| / actual water seepage rate)×100%=1-(|12.5%-13.75%| / 13.75%)×100%=90.9%.

Claims

1. The test method based on the prestressed vertical grouting pressure seepage test device is characterized in that: A prestressed vertical grouting pressure seepage test device comprises a grouting device, a pressurizing device and a columnar pressure vessel; the pressure vessel comprises a closed cylinder and a grout inlet, an exhaust port and a seepage outlet arranged on the closed cylinder; valves and pressure gauges are respectively arranged at the grout inlet and the exhaust port; the pressurizing device inflates and pressurizes the columnar pressure vessel through the exhaust port; the grouting device grouts the columnar pressure vessel through the grout inlet; the closed cylinder is composed of a cylinder and a cover plate arranged at the upper end of the cylinder; the exhaust port is provided with a valve and a pressure gauge; The cover plate is placed on the cover plate; a steel strand is arranged in the cylinder; the cover plate is welded by a carbon steel disc and a steel pipe, a hole with the same size as the outer diameter of the steel pipe is opened in the center of the disc, bolt holes are opened around it, and the pressure gauge and the ball valve are connected to the steel pipe in sequence; a carbon steel flange is welded on the top of the cylinder, bolt holes are opened around it and carbon steel stiffening ribs are added; the cylinder is fixed to the carbon steel disc of the cover plate through the carbon steel flange; the seepage outlet is connected to the steel pipe and connected to the ball valve; the grouting device adopts a grouting pump for grouting; the pressurizing device adopts an air compressor for pressurizing; the steps are: Step 1: Connect the pressurizing device to the exhaust port of the columnar pressure vessel, close the water seepage observation hole and the slurry inlet valve, open the exhaust port valve on the top of the cover plate, and proceed to the next step after the air tightness inspection is qualified; Step 2: Close the exhaust port valve on the top of the cover plate and open the slurry inlet valve; Step 3: The grout inlet is connected to the grouting device, and grouting begins in the cylindrical pressure vessel; Step 4: Observe the pressure gauges at the slurry inlet and the top of the cover plate. When the pressure value of the top pressure gauge reaches the required pressure, stop grouting and close the slurry inlet valve. The pressure gauge at the slurry inlet is used to calibrate the pressure value of the top pressure gauge. Step 5: Let it stand, and observe the top pressure gauge every 15-30 minutes. If there is pressure loss, use a pressure booster to replenish the pressure. Step 6: After the specified time, open the ball valve on the top of the cover plate to release the pressure. After the pressure is released, open the water seepage observation hole and record the water seepage height and amount of the slurry; The pressure value of the top pressure gauge is calibrated by the difference between the pressure value of the slurry inlet pressure gauge and the pressure value of the top pressure gauge. The difference between the two is 0.8-1.2 bar.

2. The test method according to claim 1, characterized in that Also includes: Step 7: Adjust the pressure or standing time and repeat the above steps to obtain multiple sets of slurry seepage height and seepage amount data.

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