Device and method for evaluating crack repairing effect of self-healing hole sealing material

Abstract

The invention belongs to the technical field of self-healing performance evaluation of self-healing hole sealing materials, and particularly discloses a device and a method for evaluating a crack repairing effect of a self-healing hole sealing material. Comprising a constant-temperature and constant-humidity chamber, a curing box, a sucking pump, a one-way valve, a flow meter, a metal container, a pressure sensor, a crack width gauge, a computer, a constant-temperature and constant-humidity chamber power switch, a temperature display, a temperature controller, a humidity display, a humidity controller, a confining pressure simulation device, a sapphire glass window, a pressure reducing valve, a gas cylinder, a plug and a self-repairing hole sealing material after crack prefabrication. Compared with the prior art, the maintenance environment of the self-repairing hole sealing material can be controlled, the crack repairing effect of the self-repairing hole sealing material in a stress state can be simulated by applying confining pressure, and the test efficiency and accuracy of a crack repairing experiment are improved.

Description

Technical Field

[0001] The invention relates to the technical field of self-healing performance evaluation of self-healing sealing materials, and in particular to a device and method for evaluating crack repair effects of self-healing sealing materials. Background Art

[0002] Coal and gas outbursts are important hidden dangers that affect the safe production of coal mines. Pre-extraction of coal seam gas through drilling is an important measure to prevent and control gas disasters. The effect of underground gas extraction is directly affected by the quality of the sealing hole. The quality of the drilling hole sealing directly determines the mining and excavation replacement cycle and whether the entire mine can be safely produced. At present, the most commonly used sealing material is cement-based material, but traditional cement materials are prone to water loss and shrinkage. Under the influence of ground stress, they are easy to crack and produce leakage channels, resulting in poor gas extraction effect. For this reason, it is proposed to develop regenerative fracture self-repairing sealing materials. When regenerative fractures appear at the grouting sealing site, the grouting sealing material can react with the leaking air to generate repair products, re-seal the fractures, and improve the extraction effect. In the study of the self-healing performance of the fractures of the self-repairing sealing material, it is necessary to pre-fabricate the fractures of the self-repairing sealing material and observe the change process of the initial fracture width of the self-repairing sealing material with the help of a high-power microscope. The fracture self-healing performance of the self-repairing sealing material is analyzed by the reduction of the fracture width.

[0003] At present, the experimental systems for observing the self-healing of cracks in sealing materials are all carried out separately through scattered instruments, which take up a large space and cannot control the temperature and humidity. At the same time, in the experimental process of observing the width of the cracks, large errors will occur due to the cumbersome experimental operation steps and the easy changes in the pre-fabricated cracks of the test samples, resulting in large differences in the experimental test results. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a device and method for evaluating the crack repair effect of a self-healing sealing material.

[0005] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a self-healing sealing material crack repair effect evaluation device, including: a constant temperature and humidity chamber, a curing chamber, an air pump, a one-way valve, a flow meter, a metal container, a pressure sensor, a crack width gauge, a computer, a constant temperature and humidity chamber power switch, a temperature display, a temperature controller, a humidity display, a humidity controller, a confining pressure simulation device, a sapphire glass window, a pressure reducing valve, a gas cylinder, a plug, and a self-healing sealing material after prefabricating the cracks;

[0007] The metal container is arranged in a curing box, and a rubber bag is installed in the metal container for placing the self-repairing sealing material after prefabricated cracks; the gas cylinder is connected to the confining pressure simulation device for applying simulated confining pressure to the self-repairing sealing material after prefabricated cracks, and a pressure reducing valve and a plug are installed between the gas cylinder and the metal container; a pressure sensor connected to the confining pressure simulation device is installed on the top of the metal container; the two ends of the metal container are respectively connected to ventilation pipes, and plugs are installed at the ends of the two ventilation pipes; a sapphire glass window is installed at one end of the metal container, and a crack width gauge is provided outside the sapphire glass window, and the crack width gauge is connected to a computer; the air inlet of the vacuum pump is connected to one of the ventilation pipes, and a one-way valve and a flow meter are connected between the air inlet of the vacuum pump and one of the ventilation pipes; the other ventilation pipe is connected to a constant temperature and humidity chamber, and a one-way valve is installed in the other ventilation pipe, and the constant temperature and humidity chamber is provided with a constant temperature and humidity chamber power switch, a temperature display, a temperature controller, a humidity display, and a humidity controller.

[0008] Furthermore, the confining pressure simulation device is an annular rubber bladder bag, a through hole is provided at the center of the annular rubber bladder bag, and a cavity is provided inside the annular rubber bladder bag.

[0009] The second technical solution of the present invention is to provide a method for evaluating the crack repair effect of a self-healing sealing material, comprising the following steps:

[0010] S1. Check the tightness of each component before conducting the experiment;

[0011] S2. Preparing a self-repairing sealing material after prefabricating the cracks externally by a prefabricated crack method;

[0012] S3. The prepared self-repairing sealing material after the prefabricated crack is placed in a metal container equipped with a confining pressure simulation device in a curing box, and the position of the self-repairing sealing material after the prefabricated crack is adjusted by a computer connected to the crack width gauge, and the crack part is aligned with the sapphire glass window to facilitate subsequent observation, and the curing box is sealed after adjustment;

[0013] S4. Open the gas cylinder to inlet and pressurize the confining pressure simulation device, adjust the pressure reducing valve to the confining pressure to be simulated, and during the air intake process, monitor the pressure changes in the confining pressure simulation device in real time, adjust the gas flow rate as needed, and ensure stable air intake;

[0014] S5. Turn on the power switch of the constant temperature and humidity chamber, adjust the setting parameters, and set the temperature and humidity to the parameters under the standard air environment: 20℃, relative humidity 50%;

[0015] S6. Turn on the vacuum pump and control the wind speed so that the air in the constant temperature and humidity chamber slowly enters the metal container, and observe and record the amount of gas flowing through the cracks of the self-repairing sealing material after the prefabricated cracks through the flow meter, record the initial flow meter parameters, and conduct real-time monitoring and record the flow meter parameters at 1d, 2d, 3d, and 7d, and judge the crack repair rate of the sealing material by the change of gas flow;

[0016] S7. Record the crack width of the self-repairing sealing material after prefabricated cracks observed in the crack width meter by a computer, record the average crack width at the beginning and the average crack width after repair for 1d, 2d, 3d, and 7d, and evaluate the crack repair rate by the change in crack width;

[0017] S8. Comprehensively evaluate the crack repair effect of the self-healing sealing material by measuring the changes in the crack width and flow meter instrument parameters of the samples at the initial time and at different repair days.

[0018] Furthermore, when preparing the self-repairing sealing material after prefabricating the cracks, firstly, the hardened cement specimen is taken out for demoulding, the cement specimen is split by a splitting experiment, a plastic sheet is placed in the middle of the two parts, and the sample is fastened with a cable tie to reserve a crack of a certain width in the middle of the repaired sample.

[0019] Furthermore, in step S6, the specific formula for determining the crack repair rate of the sealing material is as follows:

[0020]

[0021] Where: Q 0 is the initial gas flow rate; Q t is the gas flow rate at different repair days, in milliliters per minute, mL / min.

[0022] Furthermore, in step S7, the specific formula for evaluating the crack repair rate by the crack width change is as follows:

[0023]

[0024] Where: L 0 is the average crack width at the beginning; L t is the average remaining crack width after different repair days, in cm.

[0025] Compared with the prior art, the present invention places the cement sample with prefabricated cracks in a sealed box and fixes it in a metal cylindrical container with a rubber liner with a fixed support frame, connects the two ends of the sealed box to the constant temperature and humidity chamber and the vacuum pump respectively through a one-way valve, and places a crack observation instrument in the sealed box to observe the crack width through a glass window and installs a flow meter at the front end of the vacuum pump to observe the change of gas flow, while improving the external operability of the observation platform. In this way, the maintenance environment of the self-repairing sealing material can be controlled, and the crack repair effect of the self-repairing sealing material under the stress state of applying confining pressure can be simulated, thereby improving the test efficiency and accuracy of the crack repair experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the device for evaluating the crack repair effect of the self-healing sealing material of the present invention.

[0027] Figure 2 Schematic diagram of the structure of the confining pressure simulation device.

[0028] The accompanying drawings are denoted by the following symbols: constant temperature and humidity chamber 1, curing chamber 2, vacuum pump 3, one-way valve 4, flow meter 5, metal container 6, pressure sensor 7, crack width gauge 8, computer 9, constant temperature and humidity chamber power switch 10, temperature display 11, temperature controller 12, humidity display 13, humidity controller 14, confining pressure simulation device 15, cavity 1501, sapphire glass window 16, pressure reducing valve 17, gas cylinder 18, plug 19 and self-repairing sealing material 20 after prefabricated cracks. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0030] like Figure 1 , Figure 2 As shown, this embodiment exemplarily shows a self-healing sealing material crack repair effect evaluation device, including: a constant temperature and humidity chamber 1, a curing chamber 2, an air pump 3, a one-way valve 4, a flow meter 5, a metal container 6, a pressure sensor 7, a crack width gauge 8, a computer 9, a constant temperature and humidity chamber power switch 10, a temperature display 11, a temperature controller 12, a humidity display 13, a humidity controller 14, a confining pressure simulation device 15, a sapphire glass window 16, a pressure reducing valve 17, a gas cylinder 18, a plug 19 and a self-healing sealing material 20 after prefabricating cracks;

[0031] The metal container 6 is arranged in the curing box 2. The metal container 6 contains a rubber bag 15 for placing the self-repairing sealing material 20 after the prefabricated cracks. The gas cylinder 18 is connected to the confining pressure simulation device 15 to apply a simulated confining pressure to the self-repairing sealing material 20 after the prefabricated cracks. Figure 2 As shown, the confining pressure simulation device 15 is an annular rubber bladder bag, the center of which is provided with a through hole, and the interior of which is provided with a cavity 1501; a pressure reducing valve 17 and a plug 19 are installed between the gas cylinder 18 and the metal container 6, and the confining pressure is controlled by the pressure reducing valve 17; a pressure sensor 7 connected to the confining pressure simulation device 15 is installed at the top of the metal container 6 to monitor the pressure change in the annular rubber bladder bag in real time; ventilation pipes are connected to both ends of the metal container 6, and plugs 19 are installed at the ends of the two ventilation pipes for gas sealing to ensure that the container does not leak; a sapphire glass window 16 is installed at one end of the metal container 6, and a crack width gauge 8 is provided outside the sapphire glass window 16, and the crack width gauge 8 is connected to a computer Machine 9; the crack can be photographed through the sapphire glass window 16, projected on the computer 9 and observe the change in crack width; the air inlet of the vacuum pump 3 is connected to one of the ventilation pipes, and a one-way valve 4 and a flow meter 5 are connected between the air inlet of the vacuum pump 3 and one of the ventilation pipes; the other ventilation pipe is connected to the constant temperature and humidity chamber 1, and a one-way valve 4 is installed in the other ventilation pipe. The constant temperature and humidity chamber 1 is provided with a constant temperature and humidity chamber power switch 10, a temperature display 11, a temperature controller 12, a humidity display 13, and a humidity controller 14; the gas flow of the entire device can be controlled and air can be pumped, so that the air in the constant temperature and humidity chamber 1 can flow into the self-repairing sealing material continuously. The flow meter 5 can measure the amount of gas flowing through the device in real time, and further judge the change in the crack width of the self-repairing sealing material by the amount of gas.

[0032] The above device can be used to evaluate the crack repair effect of the self-healing sealing material. The specific operation steps are as follows:

[0033] 1) Check the tightness of each component before conducting the experiment.

[0034] 2) The self-repairing sealing material 20 after prefabricating the cracks is prepared externally by a prefabricated crack method. When prefabricating the cracks, firstly, the hardened cement specimen is taken out for demoulding, and the cement specimen is split by a splitting experiment, and a plastic sheet with a certain width is placed in the middle of the two parts, and after being fastened with a cable tie, a crack of a certain width is reserved in the middle of the repaired sample.

[0035] 3) The prepared self-repairing sealing material 20 for prefabricated cracks is placed in a metal container 6 equipped with an annular rubber bag in a curing box 2, and the position of the self-repairing sealing material 20 for prefabricated cracks is adjusted by a computer 9 connected to a crack width gauge 8, and the crack part is aligned with the sapphire glass window 16 to facilitate subsequent observation, and the curing box 2 is sealed after adjustment.

[0036] 4) Open the gas cylinder 18 to inlet air and pressurize the annular rubber bladder, adjust the pressure reducing valve 17 to the ambient pressure to be simulated, and during the air intake process, monitor the pressure changes in the tight annular rubber bladder in real time, adjust the gas flow rate as needed, and ensure stable air intake.

[0037] 5) Turn on the power switch 10 of the constant temperature and humidity chamber, adjust the setting parameters, and set the temperature and humidity to the parameters under the standard air environment: 20°C and relative humidity 50%. Let it stand for a few minutes to allow the temperature and humidity in the constant temperature and humidity chamber to reach the preset temperature and humidity state.

[0038] 6) Turn on the vacuum pump 3, control the wind speed, let the air in the constant temperature and humidity chamber 1 slowly enter the metal container 6, and observe and record the amount of gas flowing through the cracks of the self-repairing sealing material 20 after the prefabricated cracks through the flow meter 5, record the initial flow meter 5 parameters, and conduct real-time monitoring and record the flow meter parameters at 1d, 2d, 3d, and 7d, and judge the crack repair rate of the sealing material by the change of gas flow. The specific formula is as follows:

[0039]

[0040] Where: Q 0 is the initial gas flow rate, Q t is the gas flow rate at different repair days, in milliliters per minute (mL / min)

[0041] 7) The crack width of the self-repairing sealing material 20 after the prefabricated cracks observed in the crack width measuring instrument 8 is recorded by the computer 9, and the average crack width at the beginning and the average crack width after repairing for 1d, 2d, 3d, and 7d are recorded. The crack repair rate is evaluated by the change in crack width. The specific formula is as follows:

[0042]

[0043] Where: L 0 is the average crack width at the beginning, L t is the average remaining crack width after different repair days, in cm.

[0044] 8) The crack repair effect of the self-healing sealing material is comprehensively evaluated by the changes in the crack width of the samples and the flow meter instrument parameters at the initial time and different repair days.

[0045] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A device for evaluating the crack repair effect of a self-healing sealing material, characterized in that: include: Constant temperature and humidity chamber (1), curing chamber (2), vacuum pump (3), one-way valve (4), flow meter (5), metal container (6), pressure sensor (7), crack width gauge (8), computer (9), constant temperature and humidity chamber power switch (10), temperature display (11), temperature controller (12), humidity display (13), humidity controller (14), confining pressure simulation device (15), sapphire glass window (16), pressure reducing valve (17), gas cylinder (18), plug (19) and self-repairing sealing material (20) after prefabricating cracks; The metal container (6) is arranged in the curing box (2), and a rubber bag (15) is installed in the metal container (6) for placing the self-repairing sealing material (20) after the prefabricated cracks; the gas cylinder (18) is connected to the confining pressure simulation device (15) for applying a simulated confining pressure to the self-repairing sealing material (20) after the prefabricated cracks, and a pressure reducing valve (17) and a plug 19 are installed between the gas cylinder (18) and the metal container (6); a pressure sensor (7) connected to the confining pressure simulation device (15) is installed at the top of the metal container (6); the two ends of the metal container (6) are respectively connected to the ventilation pipes, and plugs (19) are installed at the ends of the two ventilation pipes; the metal container (6) ) is provided with a sapphire glass window (16) at one end, a crack width gauge (8) is provided outside the sapphire glass window (16), and the crack width gauge (8) is connected to a computer (9); an air inlet of the vacuum pump (3) is connected to one of the ventilation pipes, and a one-way valve (4) and a flow meter (5) are connected between the air inlet of the vacuum pump (3) and one of the ventilation pipes; the other ventilation pipe is connected to a constant temperature and humidity chamber (1), a one-way valve (4) is provided in the other ventilation pipe, and the constant temperature and humidity chamber (1) is provided with a constant temperature and humidity chamber power switch (10), a temperature display (11), a temperature controller (12), a humidity display (13), and a humidity controller (14).

2. The method for evaluating the crack repair effect of a self-healing sealing material according to claim 1, characterized in that: The confining pressure simulation device (15) is an annular rubber bag, a through hole is provided at the center of the annular rubber bag, and a cavity (1501) is provided inside the bag.

3. A method for evaluating the crack repair effect of a self-healing sealing material according to claim 1 or 2, characterized in that: The following steps are involved: S1. Check the tightness of each component before conducting the experiment; S2. Prefabricating the cracks by prefabricating the cracks externally to prepare the self-repairing sealing material (20); S3. The prepared self-repairing sealing material (20) after prefabricated cracks is placed in a metal container (6) equipped with a confining pressure simulation device (15) in a curing box (2), and the position of the self-repairing sealing material (20) after prefabricated cracks is adjusted by a computer (9) connected to a crack width gauge (8), and the crack part is aligned with the sapphire glass window (16) to facilitate subsequent observation, and the curing box (2) is sealed after adjustment; S4. Open the gas cylinder to pressurize the confining pressure simulation device (15), adjust the pressure reducing valve to the confining pressure to be simulated, and during the air intake process, monitor the pressure change in the confining pressure simulation device (15) in real time, adjust the gas flow rate as needed, and ensure stable air intake; S5. Turn on the power switch of the constant temperature and humidity chamber (10), adjust the setting parameters, and set the temperature and humidity to the parameters under the standard air environment: 20°C, relative humidity 50%; S6. Turn on the vacuum pump (3), control the wind speed, and allow the air in the constant temperature and humidity chamber (1) to slowly enter the metal container (6), and observe and record the amount of gas flowing through the cracks of the self-repairing sealing material (20) after the prefabricated cracks through the flow meter (5), record the initial flow meter (5) parameters, and conduct real-time monitoring and record the flow meter parameters at 1d, 2d, 3d, and 7d, and determine the crack repair rate of the sealing material by the change in gas flow; S7. Recording the crack width of the self-repairing sealing material (20) after prefabricated cracks observed in the crack width measuring instrument (8) by a computer (9), recording the average crack width at the beginning and the average crack width after repair for 1d, 2d, 3d, and 7d, and evaluating the crack repair rate by the change in crack width; S8. Comprehensively evaluate the crack repair effect of the self-healing sealing material by measuring the changes in the crack width and flow meter instrument parameters of the samples at the initial time and at different repair days.

4. The method for evaluating the crack repair effect of a self-healing sealing material according to claim 3, characterized in that: The self-repairing sealing material (20) after prefabricating cracks is firstly to take out the hardened cement specimen for demoulding, split the cement specimen by using a splitting experiment, place a plastic sheet in the middle of the two parts, and tie it with a cable tie to reserve a crack of a certain width in the middle of the repaired sample.

5. The method for evaluating crack repair effect of the self-healing sealing material according to claim 3, characterized in that: In step S6, the specific formula for determining the crack repair rate of the sealing material is as follows: Where: Q0 is the initial gas flow rate; Q t is the gas flow rate at different repair days, in milliliters per minute, mL / min.

6. The method for evaluating crack repair effect of the self-healing sealing material according to claim 3, characterized in that: In step S7, the specific formula for evaluating the crack repair rate by the crack width change is as follows: Where: L0 is the average crack width at the initial time; L t is the average remaining crack width after different repair days, in cm.

Images