Test system and test method for high-frequency pulsation grouting slurry diffusion of tiny cracks of rock stratum

Abstract

The invention relates to the technical field of rock stratum fracture grouting tests, in particular to a high-frequency pulsation grouting slurry diffusion testing system and method for tiny rock stratum fractures, and the high-frequency pulsation grouting slurry diffusion testing system comprises a slurry supply unit; the testing system further comprises a grouting pipe, an electromagnetic valve, a pulsation controller and a slab fracture model. One end of the grouting pipe is communicated with the slurry supply unit and is used for conveying slurry; the electromagnetic valve is arranged on the grouting pipe and is used for opening or closing the grouting pipe; the pulsation controller is arranged on one side of the electromagnetic valve, electrically connected with the electromagnetic valve and used for controlling the electromagnetic valve to be opened according to the rated pulsation frequency, and the rated pulsation frequency is larger than or equal to 0 hz and smaller than or equal to 10 hz; the plate crack model is arranged at the end, away from the slurry supply unit, of the grouting pipe and communicates with the grouting pipe. According to the method, the grouting advantages of the pulsating grouting method in the tiny cracks are verified, the higher the frequency is, the more obvious the advantages are, and meanwhile the diffusion uniformity of grout obtained after grouting is better.

Description

Technical Field

[0001] This invention relates to the field of rock fracture grouting test technology, specifically to a high-frequency pulsating grout diffusion test system and test method for rock fracture micro-fractures. Background Technology

[0002] Traditional grouting technology is carried out under pressure and is widely used for seepage prevention, plugging, and ground reinforcement. Under pressure, grout particles easily clog pore channels, resulting in low grouting efficiency. 60% to 80% of the grout tends to flow along the dominant channels, leading to poor uniformity and high economic costs.

[0003] Chinese Patent Publication No. CN108519308B discloses a method for testing the diffusion of grout in rock masses with penetrating fractures. The method includes: Step 1, determining the structural surface characteristic parameters of the fractured rock mass: fracture spatial orientation, strike, dip, hydraulic pore width, rock strata properties, roughness, and excavation stress; simultaneously scanning the connectivity of the fracture network and digitally processing the penetrating fracture parameters; Step 2, based on the penetrating fracture parameters, using appropriate printing materials and a 3D printer to print penetrating fractures. The thickness of the printed penetrating fracture shell meets the test preload requirements, and the penetrating fracture skeleton is hollow, with the inner diameter of the hollow being the hydraulic width of the fracture; Step 3, pre-setting the determined hollow penetrating fracture as the skeleton on the test device, and arranging monitoring elements at the two ends and key areas in the middle of the fracture according to the test requirements and connecting them to a PC; Step 4, using… One end of the sampling capillary is connected to the end of the through-fracture, and the other end is connected to the water pump to effectively control the water saturation of the fracture. At the same time, rock gravel is evenly laid around the through-fracture for stratification treatment, ensuring the safety of the sampling capillary during the treatment. Step five: After the rock strata are laid, the rock strata are cooled and a pre-tightening force is applied to the rock strata using a test bench loading frame and a servo stress loader to simulate in-situ stress. After loading, a high-temperature grouting operation is performed into the fracture using a grouting pump. During this process, the reaction signals of the monitoring elements at different locations are recorded in real time, and the diffusion line and velocity of the grout are recorded using a thermal sensor. The real-time changes of the grouting parameters are also recorded. Step six: After the grouting is completed and the grout solidifies, the device is demolded, the rock gravel is removed, and the diffusion and solidification of the grout in the through-fracture are observed.

[0004] The above scheme allows for observation of grout diffusion, but it does not improve the grouting method. In recent years, a new grouting method has emerged, which uses intermittent grouting. During grouting, the grouting pump is started intermittently to apply intermittent pressure to achieve grouting. Intermittent grouting effectively solves the problem of particle blockage. However, during the intermittent period, the lack of grouting pressure in the test equipment causes the grout to be unable to flow smoothly in the test equipment. In practical applications, this will lead to a reduction in the efficiency of seepage prevention, plugging, or stratum reinforcement. Summary of the Invention

[0005] To address the aforementioned issues, a high-frequency pulsating grout diffusion testing system and method for micro-fractures in rock strata are provided. This system comprises a grout supply unit, grouting pipe, solenoid valve, pulsation controller, and a flat plate fracture model. The grout supply unit discharges grout into the flat plate fracture model, and the pulsation controller controls the solenoid valve to continuously open and close at a rated pulsation frequency, thus completing the pulsating grouting test. Simultaneously, a secondary test is conducted using pressure-stabilized grouting. The two sets of data are then compared: the diffusion radius of the grout formed by pressure-stabilized grouting is compared with that formed by pulsating grouting. The diffusion radius of the grout formed by pulsating grouting is significantly larger than that formed by pressure-stabilized grouting.

[0006] To address the problems of existing technologies, this invention provides a high-frequency pulsating grout diffusion testing system for micro-fractures in rock strata, including a grout supply unit;

[0007] The testing system also includes grouting pipes, solenoid valves, pulse controllers, and flat plate fracture models;

[0008] One end of the grouting pipe is connected to the grout supply unit and is used to transport grout.

[0009] The solenoid valve is installed on the grouting pipe and is used to open or disconnect the grouting pipe;

[0010] The pulse controller is located on one side of the solenoid valve and is electrically connected to the solenoid valve. The pulse controller is used to control the solenoid valve to open according to the rated pulse frequency, 0 Hz ≤ rated pulse frequency ≤ 10 Hz.

[0011] The flat plate fracture model is set at the end of the grouting pipe away from the grouting unit, and the flat plate fracture model is connected to the grouting pipe.

[0012] Preferably, the plate crack model includes a transparent plate;

[0013] Two transparent plates are provided, which are arranged parallel to each other with a gap between them. The gap is used to simulate the micro-fractures in the rock strata. A grouting port is provided on the upper transparent plate and is connected to the grouting pipe.

[0014] A camera is installed on the upper part of the flat plate crack model, with the camera end facing the flat plate crack model.

[0015] Preferably, the flat plate crack model also includes a fixing assembly for fixing the two transparent plates, the fixing assembly including gaskets and bolts;

[0016] The gasket is placed between the two transparent plates;

[0017] There are multiple bolts, which pass through one of the transparent plates and are threaded into another transparent plate.

[0018] Preferably, the transparent sheet is made of transparent colorless acrylic sheet.

[0019] This invention also relates to a method for testing the diffusion of grout in high-frequency pulsating grouting in micro-fractures of rock strata, using a high-frequency pulsating grouting diffusion testing system for micro-fractures of rock strata. The specific steps are as follows:

[0020] Step 1, Adjustment: Place the shim between the two transparent plates, ensuring a distance of 0.3mm between them.

[0021] Step 2, Comparative Test: Using pressure-stabilized grouting as the control group and pulsating grouting as the test group, grouting was performed sequentially within the specified spacing according to the test order, with the same test time for each time; after each grouting, the grout remaining in the spacing was cleaned up.

[0022] Step 3, Data Detection: Record the grout diffusion during the test using a camera, and record the final grout diffusion radius formed by pressure stabilization grouting and pulse grouting;

[0023] Step 4: Data Analysis: Analyze the results of pulsating grouting and pressure stabilization grouting under different pulsation frequencies and output charts.

[0024] Preferably, in step 2, the test groups are divided into a 10Hz test group, a 5Hz test group, and a 2.5Hz test group according to the pulsation frequency of the pulsation grouting.

[0025] Preferably, in step 3, after the camera captures the diffusion shape of the slurry in the test group, the diffusion shape is approximately circular, and the processor performs circularization processing on the diffusion shape and calculates the average radius.

[0026] Preferably, the slurry diffusion radius corresponding to the 10Hz test group, 5Hz test group and 2.5Hz test group is plotted as a line graph according to the change of test time, and the test time is 3 seconds.

[0027] Preferably, the pulse frequency is set to 5 Hz, the distance between the two transparent plates is adjusted, and a pulse grouting test and a pressure-stabilized grouting test are performed after each adjustment, with the pressure-stabilized grouting test serving as the control group.

[0028] Preferably, during the pulsating grouting test, due to the continuous opening and closing of the solenoid valve, an oscillating pressure is formed in the flat plate crack model, and the oscillating pressure is 150000*sin(6.28*5.4[rad / s]*t)+300000.

[0029] The advantages of this invention compared to the prior art are:

[0030] 1. This invention, by setting up a grout supply unit, grouting pipe, solenoid valve, pulsation controller, and flat plate fracture model, allows the grout supply unit to discharge grout into the flat plate fracture model. The pulsation controller controls the solenoid valve to continuously open and close at a rated pulsation frequency, thus completing the pulsation grouting test. Simultaneously, a secondary test is conducted using pressure-stabilized grouting. The two sets of data are compared: the grout diffusion radius formed by pressure-stabilized grouting is compared with that formed by pulsation grouting. The grout diffusion radius formed by pulsation grouting is significantly larger than that formed by pressure-stabilized grouting, indicating that within 0.3... In the gap of mm, the efficiency of traditional pressure-stabilized grouting is lower than that of pulsed grouting. At the same time, due to the long interval of existing intermittent grouting, it is impossible to guarantee that the grout will be under pressure throughout the grouting process. When the grout is not under pressure, it cannot move within the gap. Therefore, the efficiency of existing intermittent grouting is also lower than that of pulsed grouting. Therefore, the high-frequency pulsed grouting method in this invention has the advantage of higher efficiency compared with traditional pressure-stabilized grouting and existing intermittent grouting. In addition, the grout diffusion shape formed by pulsed grouting is more uniform. When applied to actual operations, it can fill the micro-cracks in the rock strata more efficiently.

[0031] 2. The pulsation frequency during pulsation grouting must be greater than or equal to 5 Hz. When the pulsation frequency of pulsation grouting is greater than or equal to 5 Hz, the grout diffusion radius formed by pulsation grouting is significantly increased compared with that of constant pressure grouting.

[0032] 3. By changing the gap between the two transparent plates and using a constant pulsation frequency of at least 5 Hz for pulsation grouting, the analysis revealed that the increase in grout diffusion distance after pulsation grouting was negatively correlated with time, indicating that the grouting speed of pulsation grouting technology under micro-crack conditions is significantly improved compared with the grouting speed of pressure-stabilized grouting. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the configuration of the high-frequency pulsating grout diffusion test system for micro-fractures in rock strata according to the present invention.

[0034] Figure 2 This is a side view of a flat plate fracture model in the high-frequency pulsating grout diffusion test system for micro-fractures in rock strata of the present invention.

[0035] Figure 3 This is a graph showing the change in the slurry diffusion radius when the high-frequency pulsating grouting slurry diffusion testing system for micro-fractures in rock strata of this invention is tested using the pressure-stabilized grouting method.

[0036] Figure 4 This is a graph showing the change in the slurry diffusion radius when the high-frequency pulsating grouting slurry diffusion test system for micro-cracks in rock strata of this invention is tested using the pulsating grouting method with a pulsating frequency of 5 Hz.

[0037] Figure 5This is a line graph showing the effect of fracture opening on the pulsating grouting method using the high-frequency pulsating grout diffusion test system for micro-fractures in rock strata according to the present invention.

[0038] Figure 6 This is a graph showing the change in the slurry diffusion radius when the high-frequency pulsating grouting slurry diffusion test system for micro-cracks in rock strata is tested using a 10Hz pulsating grouting method.

[0039] Figure 7 This is a graph showing the change in the slurry diffusion radius when the high-frequency pulsating grouting slurry diffusion test system for micro-cracks in rock strata of this invention is tested using the pulsating grouting method with a pulsating frequency of 2.5 Hz.

[0040] Figure 8 This is a line graph showing the changes in the diffusion diameter of grout formed by the high-frequency pulsating grouting method and the diffusion diameter formed by the pressure-stabilized grouting method at different frequencies over time using the high-frequency pulsating grouting diffusion test system for micro-fractures in rock strata of this invention.

[0041] Figure 9 This is a pressure waveform diagram of the high-frequency pulsating grout diffusion test system for micro-cracks in rock strata of the present invention when tested using a pulsating frequency of 2.5 Hz.

[0042] Figure 10 This is a pressure waveform diagram of the high-frequency pulsating grout diffusion test system for micro-cracks in rock strata according to the present invention, when tested at a pulsating frequency of 5 Hz.

[0043] Figure 11 This is a pressure waveform diagram of the high-frequency pulsating grout diffusion test system for micro-cracks in rock strata of the present invention during testing at a pulsating frequency of 10 Hz.

[0044] The following are the labels in the diagram: 1. Grouting unit; 11. Air compressor; 12. Air supply pipe; 13. Pressure tank; 131. Pressure regulating valve; 132. Electronic pressure gauge; 133. Safety valve; 2. Grouting pipe; 3. Solenoid valve; 4. Pulse controller; 5. Flat plate fracture model; 51. Transparent plate; 52. Gasket; 53. Bolt. Detailed Implementation

[0045] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0046] Reference Figure 1 : High-frequency pulsating grout diffusion testing system for micro-fractures in rock strata, including grout supply unit 1;

[0047] The testing system also includes a grouting pipe 2, a solenoid valve 3, a pulse controller 4, and a flat plate fracture model 5;

[0048] One end of the grouting pipe 2 is connected to the grout supply unit 1 and is used to transport grout;

[0049] Solenoid valve 3 is installed on grouting pipe 2 and is used to open or disconnect grouting pipe 2;

[0050] The pulse controller 4 is located on one side of the solenoid valve 3 and is electrically connected to the solenoid valve 3. The pulse controller 4 is used to control the solenoid valve 3 to open according to the rated pulse frequency, 0 Hz ≤ rated pulse frequency ≤ 10 Hz.

[0051] The flat plate fracture model 5 is set at the end of the grouting pipe 2 away from the grout supply unit 1, and the flat plate fracture model 5 is connected to the grouting pipe 2.

[0052] The grout supply unit 1 includes an air compressor 11, an air supply pipe 12, and a pressure tank 13. The air compressor 11 is connected to the upper part of the pressure tank 13 via the air supply pipe 12, providing a constant air pressure to the pressure tank 13. A pressure regulating valve 131, an electronic pressure gauge 132, and a safety valve 133 are installed on the upper part of the pressure tank 13. The electronic pressure gauge 132 is used to detect the grouting pressure in real time. A processor is connected to one side of the electronic pressure gauge 132. The grouting pressure detected by the electronic pressure gauge 132 is processed by the processor, which then sends a command to the controller, causing the pressure regulating valve 131 to control the grouting pressure in the pressure tank 13. The rated pressure of the safety valve 133 is 0.8 MPa. When the air pressure in the pressure tank 13 exceeds the rated value, the safety valve 133 automatically releases pressure to ensure experimental safety. A grouting port is provided on the upper part of the flat plate fracture model 5. A grouting pipe 2 is provided between the pressure tank 13 and the flat plate fracture model 5. The two ends of the grouting pipe 2 are connected to the bottom of the pressure tank 13 and the grouting port on the upper part of the flat plate fracture model 5, respectively.

[0053] During the grouting test, pressure is applied to the pressure tank 13 by the air compressor 11. The pressure tank 13 contains grout. When the pressure in the pressure tank 13 reaches the preset value of the pressure regulating valve 131, the air compressor 11 stops running. Then, the solenoid valve 3 is controlled by the pulse controller 4, causing the solenoid valve 3 to open and close continuously according to the rated pulse frequency. The rated pulse frequency is between 0-10 Hz, where 0 Hz ≤ rated pulse frequency ≤ 10 Hz. In this test, the rated pulse frequencies used are 10 Hz, 5 Hz, and 2.5 Hz for testing. After the test, the grout diffusion test system needs to stand for 3 minutes. Then, the grouting pipe 2 is removed from the grouting port on the top of the flat crack model 5 and cleaned to prevent blockage.

[0054] Reference Figure 1 and Figure 2 The flat plate crack model 5 includes a transparent plate 51;

[0055] Two transparent plates 51 are provided. The two transparent plates 51 are arranged parallel to each other and there is a gap between the two transparent plates 51. The gap is used to simulate the micro-fractures in the rock strata. A grouting port is opened on the upper transparent plate 51 and is connected to the grouting pipe 2.

[0056] A camera is installed on the upper part of the flat plate crack model 5, with the camera end facing the flat plate crack model 5.

[0057] During the test, the grouting pipe 2 injects grout into the gap between the two transparent plates 51 through the grouting port, and the camera detects the diffusion state of the grout injected between the two transparent plates 51.

[0058] Reference Figure 1 and Figure 2 The flat plate crack model 5 also includes a fixing assembly for fixing the two transparent plates 51, which includes a gasket 52 and a bolt 53.

[0059] The gasket 52 is disposed between the two transparent plates 51;

[0060] Multiple bolts 53 are provided, and the bolts 53 pass through one of the transparent plates 51 and are threaded into another transparent plate 51.

[0061] According to the experimental requirements, the gaskets 52 can be divided into three types: 0.3mm, 0.5mm and 1mm, depending on their thickness. Each test requires the use of a gasket 52 of uniform thickness placed between two transparent plates 51.

[0062] Reference Figure 2 Transparent panel 51 is made of transparent colorless acrylic sheet.

[0063] To ensure the accuracy of the camera's detection results during the experiment, the transparent plate 51 needs to remain colorless and transparent. Since the transparent plate 51 needs to withstand pressure during the test, and acrylic sheets have good impact and pressure resistance, it is safer than glass if the transparent plate 51 breaks during the test. Furthermore, acrylic sheets are lightweight. Before each test, the slurry remaining between the two transparent plates 51 from the previous test must be removed. Before removal, the upper transparent plate 51 needs to be removed to ensure that its weight does not cause excessive effort during removal.

[0064] Reference Figure 3 and Figure 4 This invention also relates to a method for testing the diffusion of grout in high-frequency pulsating grouting in micro-fractures of rock strata, employing a high-frequency pulsating grout diffusion testing system for micro-fractures of rock strata. The specific steps are as follows:

[0065] Step 1, Adjustment: Place the shim 52 between the two transparent plates 51, so that the distance between the two transparent plates 51 is 0.3mm.

[0066] Step 2, Comparative Test: Using pressure-stabilized grouting as the control group and pulsating grouting as the test group, grouting was performed sequentially within the specified spacing according to the test order, with the same test time for each time; after each grouting, the grout remaining in the spacing was cleaned up.

[0067] Step 3, Data Detection: Record the grout diffusion during the test using a camera, and record the final grout diffusion radius formed by pressure stabilization grouting and pulse grouting;

[0068] Step 4: Data Analysis: Analyze the results of pulsating grouting and pressure stabilization grouting under different pulsation frequencies and output charts.

[0069] By comparing the grout diffusion radius formed by pressure-stabilized grouting with that formed by intermittent grouting, the diffusion radius of the grout formed by intermittent grouting is significantly larger than that formed by pressure-stabilized grouting. This indicates that within a 0.3mm gap, the efficiency of traditional pressure-stabilized grouting is lower than that of intermittent grouting. Furthermore, due to the long intervals in existing intermittent grouting methods, it is impossible to guarantee continuous pressure during the grouting process. When the grout is not under pressure, it cannot move within the gap. Therefore, the efficiency of existing intermittent grouting is also lower than that of intermittent grouting. Additionally, according to... Figure 3 and Figure 4 In comparison, the grout diffusion shape formed by pulsed grouting is more uniform, and it can fill the tiny cracks in the rock strata more efficiently when applied to actual operations.

[0070] Reference Figure 4 , Figure 6 and Figure 7 In step 2, the test groups are divided into 10Hz test group, 5Hz test group and 2.5Hz test group according to the pulsation frequency of the pulsation grouting.

[0071] Figure 6 This corresponds to the 10Hz test group. Figure 4 This corresponds to the 5Hz test group. Figure 7 This corresponds to the 2.5Hz test group.

[0072] Reference Figure 4 , Figure 6 and Figure 7 In step 3, after the camera captures the diffusion shape of the slurry in the test group, the diffusion shape is roughly circular. The processor then performs a circularization process on the diffusion shape and calculates the average radius.

[0073] Based on the pulsation frequency of the grouting, the test groups were divided into 10Hz, 5Hz and 2.5Hz. The final grout diffusion shape formed in the above three test groups all exhibited a near-circular structure. In order to facilitate calculation and comparison, the near-circular structure needs to be rounded by the processor so that the processed grout diffusion shape is a perfect circle, and the radius of the corresponding grout diffusion shape is calculated.

[0074] Reference Figure 8 The diffusion radius of the slurry corresponding to the 10Hz test group, 5Hz test group and 2.5Hz test group was plotted as a line graph according to the change of test time, and the test time was 3 seconds.

[0075] After plotting the slurry diffusion radius of the 10Hz, 5Hz, and 2.5Hz test groups as a function of test time into a line graph, and then... Figure 8 The graph includes a line segment with a pulsation frequency of 0, representing the pulsation during pressure-stabilized grouting. Comparison shows that when the gap between the two transparent plates 51 is 0.3 mm, a higher pulsation frequency results in a larger slurry diffusion radius. From... Figure 8 As can be seen from the data, at time 3s, the grout diffusion radius of the 10Hz test group is 280.1mm, while the grout diffusion radius corresponding to pressure-stabilized grouting is 248.2mm, an increase of 12.8%. However, at a pulsation frequency of 2.5Hz, the grout diffusion radius of pulsating grouting is basically the same as that of pressure-stabilized grouting. But at a pulsation frequency of 5Hz, there is a significant difference between the grout diffusion radius of pulsating grouting and that of pressure-stabilized grouting, meaning that the grout diffusion radius of pulsating grouting is significantly larger than that of pressure-stabilized grouting. Therefore, in practical applications, the pulsation frequency of pulsating grouting needs to be greater than or equal to 5Hz to ensure that when pulsating grouting micro-cracks, a pulsation frequency greater than or equal to 5Hz is used, and the grouting speed of pulsating grouting is significantly faster than that of pressure-stabilized grouting.

[0076] Reference Figure 5 The pulse frequency was set to 5 Hz, the distance between the two transparent plates 51 was adjusted, and a pulse grouting test and a pressure-stabilized grouting test were performed after each adjustment, with the pressure-stabilized grouting test serving as the control group.

[0077] according to Figure 5As shown, within the 0-3s time period, the grout diffusion radius of both grouting modes exhibited a significant increasing trend with time. The pulsating grouting method showed the best effect at 0.5s, with a diffusion radius of 95.84mm for pulsating grouting and 85.73mm for pressure-controlled grouting, representing an 11.8% increase in diffusion distance. The diffusion distance of pulsating grouting was significantly better than that of pressure-controlled grouting. Further analysis revealed a negative correlation between the diffusion distance increase and time, indicating that pulsating grouting technology significantly improves the grouting speed under micro-crack conditions compared to pressure-controlled grouting.

[0078] Reference Figures 9-11 During the pulsating grouting test, due to the continuous opening and closing of the solenoid valve 3, an oscillating pressure is formed in the flat plate crack model 5. The oscillating pressure is 150000*sin6.28*5.4[rad / s]*t+300000.

[0079] As can be seen from the oscillation pressure diagrams at 2.5Hz, 5Hz, and 10Hz, the grouting pressure during the pulsating grouting process never drops to 0. This ensures that the grout is constantly pushed and diffused by pressure during the grouting process, thus achieving a faster pulsating grouting speed than existing intermittent grouting methods.

[0080] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A high-frequency pulsating grout diffusion test system for micro-fractures in rock strata, including a grout supply unit (1); Its features are, The testing system also includes a grouting pipe (2), a solenoid valve (3), a pulse controller (4), and a flat plate fracture model (5); One end of the grouting pipe (2) is connected to the grouting unit (1) and used to transport grout; The solenoid valve (3) is installed on the grouting pipe (2) and is used to open or close the grouting pipe (2); The pulse controller (4) is located on one side of the solenoid valve (3) and is electrically connected to the solenoid valve (3). The pulse controller (4) is used to control the solenoid valve (3) to open according to the rated pulse frequency, 0hz≤rated pulse frequency≤10hz; The flat plate fracture model (5) is set at the end of the grouting pipe (2) away from the grouting unit (1), and the flat plate fracture model (5) is connected to the grouting pipe (2).

2. The high-frequency pulsating grout diffusion testing system for micro-fractures in rock strata according to claim 1, characterized in that, The plate crack model (5) includes a transparent plate (51); Two transparent plates (51) are provided. The two transparent plates (51) are arranged parallel to each other and there is a gap between the two transparent plates (51). The gap is used to simulate the micro-cracks in the rock strata. The upper transparent plate (51) is provided with a grouting port and is connected to the grouting pipe (2). A camera is installed on the upper part of the flat plate crack model (5), with the camera end facing the flat plate crack model (5).

3. The high-frequency pulsating grout diffusion testing system for micro-fractures in rock strata according to claim 2, characterized in that, The flat plate crack model (5) also includes a fixing assembly for fixing the two transparent plates (51), which includes a gasket (52) and a bolt (53); A gasket (52) is placed between two transparent plates (51); Multiple bolts (53) are provided, and the bolts (53) pass through one of the transparent plates (51) and are threaded into another transparent plate (51).

4. The high-frequency pulsating grout diffusion testing system for micro-fractures in rock strata according to claim 2, characterized in that, The transparent panel (51) is made of transparent colorless acrylic sheet.

5. A method for testing the diffusion of grout in high-frequency pulsating grouting in micro-fractures of rock strata, employing the high-frequency pulsating grout diffusion testing system for micro-fractures of rock strata as described in claim 3, characterized in that... The specific steps are as follows: Step 1, Adjustment: Place the shim (52) between the two transparent plates (51) so that the distance between the two transparent plates (51) is 0.3mm. Step 2, Comparative Test: Using pressure-stabilized grouting as the control group and pulsating grouting as the test group, grouting was performed sequentially within the specified spacing according to the test order, with the same test time for each time; after each grouting, the grout remaining in the spacing was cleaned up. Step 3, Data Detection: Record the grout diffusion during the test using a camera, and record the final grout diffusion radius formed by pressure stabilization grouting and pulse grouting; Step 4: Data Analysis: Analyze the results of pulsating grouting and pressure stabilization grouting under different pulsation frequencies and output charts.

6. The method for testing the diffusion of grout in high-frequency pulsating grouting in micro-fractures of rock strata according to claim 5, characterized in that, In step 2, the test groups are divided into 10Hz test group, 5Hz test group and 2.5Hz test group according to the pulsation frequency of the pulsation grouting.

7. The method for testing the diffusion of grout in high-frequency pulsating grouting in micro-fractures of rock strata according to claim 5, characterized in that, In step 3, after the camera captures the diffusion shape of the slurry in the test group, the diffusion shape is roughly circular. The processor then performs a circularization process on the diffusion shape and calculates the average radius.

8. The method for testing the diffusion of grout in high-frequency pulsating injection in micro-fractures of rock strata according to claim 6, characterized in that, The slurry diffusion radius corresponding to the 10Hz, 5Hz and 2.5Hz test groups was plotted as a line graph according to the change of test time, with the test time being 3 seconds.

9. The method for testing the diffusion of grout in high-frequency pulsating injection in micro-fractures of rock strata according to claim 5, characterized in that, The pulse frequency was set to 5 Hz, the distance between the two transparent plates (51) was adjusted, and a pulse grouting test and a pressure stabilizing grouting test were performed after each adjustment, with the pressure stabilizing grouting test serving as the control group.

10. The method for testing the diffusion of grout in high-frequency pulsating grouting in micro-fractures of rock strata according to claim 5, characterized in that, During the pulsating grouting test, the continuous opening and closing of the solenoid valve (3) creates oscillating pressure in the flat plate crack model (5).

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