A coal rock mass crushing compaction grouting test device and method

Abstract

The application discloses a kind of broken coal rock mass compaction grouting test device and method, the device includes pressure bearing fixed plate and cylinder, the pressure bearing fixed plate is set in the upper of cylinder, and pressure bearing fixed plate is connected with cylinder by bolt, the lower surface of pressure bearing fixed plate is provided with multiple steel columns, steel column is connected with backing plate below and backing plate periphery is wrapped rubber pad, the middle part of backing plate is provided with exhaust port, exhaust port is connected with exhaust hose;The bottom of cylinder is provided with grouting pipe, the grouting pipe is connected with grouting system;The application can simulate the filling reinforcement process of coal mine goaf under different stress conditions, grouting test can be carried out under the condition that pressure is invariable, test device structure is simple, easy to disassemble, and it is favorable to standard sampling after grouting model sample, further analyzes the characteristics of grouting reinforcement body.

Description

Technical Field

[0001] This invention relates to the technical field of filling tests for goaf areas in underground engineering, specifically to a test device and method for compaction grouting of fractured coal and rock masses. Background Technology

[0002] Grouting technology utilizes principles such as air pressure and hydraulic pressure to inject certain solidifiable grouts into fissures or pores in soil or rock layers, causing the grout and rock layers to solidify and bond together. Currently, grouting technology is widely used in tunnel engineering, slope engineering, foundation engineering, and dam engineering, playing a unique and irreplaceable role in geological disaster control, underground rock reinforcement, and structural strengthening. It provides crucial protection for the construction and operational safety of transportation, building, mining, water conservancy, and pipeline projects.

[0003] To obtain more coal resources, the most common mining method currently used is backfilling mining, which has the advantage of extremely high coal extraction rate and can effectively improve mining efficiency. However, its relatively complex process and high cost have hindered the widespread adoption of this mining technology. In underground coal mine grouting projects, reasonable grouting materials, grout ratio, and grouting pressure are important foundations for the successful application of grouting modification and reinforcement technology. Due to the strong concealment of grouting modification and reinforcement, the complex on-site procedures, and the high construction cost, the grout flows, diffuses, and solidifies deep within the coal and rock mass under pressure, making it difficult to conduct in-situ experiments and evaluate the effect of grouting modification and reinforcement in underground coal mines.

[0004] Although some grouting test devices exist in the existing technology, they have the following drawbacks: due to the complexity and variability of coal and rock masses, it is difficult for model tests to be similar to the coal and rock masses underground in all aspects. When simulating grouting reinforcement, due to the limitations of the test equipment, the flow and diffusion of the model grout in the coal and rock mass cannot be realistically observed, which seriously affects the effect and reliability of the model test. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a test device and method for compaction grouting of fractured coal and rock mass, which can simulate the filling and reinforcement process of coal mine goaf under different stress conditions, and improve the accuracy of the data obtained from the simulation test.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the invention, a test device for compaction grouting of fractured coal and rock mass is provided, comprising a pressure-bearing fixing plate and a cylinder. The pressure-bearing fixing plate is disposed above the cylinder and is connected to the cylinder by bolts. A plurality of steel columns are disposed on the lower surface of the pressure-bearing fixing plate. A steel plate is connected below the steel columns and a rubber pad is wrapped around the outer periphery of the plate. An exhaust port is disposed in the middle of the steel plate and is connected to an exhaust hose. A grouting pipe is disposed at the bottom of the cylinder and is connected to a grouting system.

[0008] In some embodiments of the present invention, the bolts comprise a plurality of bolts, which are fixed to the lower surface of the pressure-bearing fixing plate by welding and are evenly arranged along the outer periphery of the pressure-bearing fixing plate.

[0009] In some embodiments of the present invention, the top of the cylinder is provided with an outer edge steel plate, and the outer edge steel plate is provided with a plurality of bolt holes, which correspond to the bolts on the pressure-bearing fixing plate.

[0010] In some embodiments of the present invention, the outer diameter of the rubber pad is the same as the inner diameter of the cylinder, and the rubber pad and the cylinder remain in close contact during the compaction process.

[0011] In some embodiments of the present invention, the grouting system includes a grouting pipe, a grouting bend, a grouting bucket, a grouting hose, and an air compressor connected in sequence.

[0012] In some embodiments of the present invention, a grouting pipe valve is provided on the grouting pipe, and a grouting bend valve is provided on the grouting bend.

[0013] In some embodiments of the present invention, the connection between the grouting pipe and the grouting bend is sealed with a sealing ring.

[0014] In some embodiments of the present invention, an exhaust hose valve is provided inside the exhaust hose.

[0015] In a second aspect of the present invention, a method for compaction grouting test of fractured coal and rock mass is provided, comprising the following steps:

[0016] (1) Place the cylinder on the servo machine, put the crushed coal and rock into the cylinder, and put the whole assembly consisting of the pressure fixing plate and the pad wrapped with rubber pad into the cylinder. At this time, all valves are closed.

[0017] (2) Using computer-controlled servo motor hydraulic rods to apply a set load to the device to simulate the stress on the broken coal and rock mass in the goaf;

[0018] (3) After loading is completed, the pressure fixing plate is fixed to the cylinder with high-strength bolts to fix the position of the pad and keep the pressure state of the crushed coal and rock mass unchanged at this time;

[0019] (4) Remove the device and place it on the support frame. Grout the compacted broken coal and rock mass in the device through the grouting system. Stop grouting after the predetermined grouting effect is achieved, and cure the sample.

[0020] (5) After the grouting sample is cured, it is demolded and can be ground into a standard sample, numbered, so that subsequent mechanical tests can be carried out.

[0021] In some embodiments of the present invention, in step (2), the pressure loading range is 0-3 MPa.

[0022] One or more technical solutions of the present invention have the following beneficial effects:

[0023] The test device for compaction grouting of fractured coal and rock mass provided by the present invention can simulate the filling and reinforcement process of coal mine goaf under different stress conditions. Grouting tests can be carried out under constant pressure. The test device has a simple structure, is easy to disassemble, and is conducive to standard sampling of model samples after grouting, so as to further analyze the characteristics of the grouting solid.

[0024] The crushed coal and rock mass compaction grouting test device provided by the present invention can, after the hydraulic rod applies a set load to the device to simulate the stress on the crushed coal and rock mass in the goaf, fix the pressure fixing plate and the cylinder together with the set high-strength bolts to fix the position of the pad plate and keep the pressure state on the crushed coal and rock mass unchanged at this time.

[0025] The crushed coal and rock mass compaction grouting test device provided by the present invention uses high-strength bolts to fix the position of the pressure plate. This allows the cylinder to be disassembled and placed on the support frame for grouting while maintaining the pressure state. It also allows for subsequent maintenance and other work while saving on uniaxial compression test equipment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the test device for compaction grouting of fractured coal and rock mass according to the present invention;

[0027] Figure 2 This is a front view of the cylinder and pressure-bearing fixing plate of the present invention;

[0028] Figure 3 This is a front view of the pressure-bearing fixing plate of the present invention;

[0029] Figure 4 This is a schematic diagram of the installation of the cylinder and grouting pipe of the present invention.

[0030] In the diagram: 1-Pressure bearing plate; 2-Bolt; 3-Exhaust hose valve; 4-Exhaust hose; 5-Steel column; 6-Rubber pad; 7-Bolt hole; 8-Cylinder; 9-Grouting pipe; 10-Grouting pipe valve; 11-Support frame; 12-Grouting bend valve; 13-Sealing ring; 14-Grouting bend; 15-Grouting bucket; 16-Grouting hose; 17-Air compressor. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Example 1

[0033] In a typical embodiment of the present invention, such as Figure 1 As shown, a test device for compaction grouting of crushed coal and rock mass is proposed, including a pressure-bearing fixing plate 1 and a cylinder 8. The pressure-bearing fixing plate 1 is set above the cylinder 8 and is connected to the cylinder 8 by bolts 2. Multiple steel columns 5 are set on the lower surface of the pressure-bearing fixing plate 1. A pad is connected below the steel columns 5. The pad is a circular steel plate with a rubber pad 6 wrapped around its outer periphery. When pressurized, it can fit tightly against the cylinder to increase the compaction of the crushed coal and rock mass. An exhaust port is set in the middle of the pad and is connected to an exhaust hose 4. A grouting pipe 9 is set at the bottom of the cylinder 8 and is connected to the grouting system.

[0034] like Figure 2 and Figure 3 As shown, the pressure-bearing fixing plate 1 is circular in shape, with multiple bolts (specifically four) used. These high-strength bolts are welded to the lower surface of the pressure-bearing fixing plate and evenly distributed along its outer perimeter. Multiple steel columns 5 are arranged within the inner ring of the pressure-bearing fixing plate 1, with steel plates connected to the bottom of each column. Eight steel columns 5 are used, with each column longer than the bolt. The pressure-bearing fixing plate, steel columns, bolts, and a pad encasing a rubber gasket constitute a pressure-bearing pad module. After the load is applied, the pressure-bearing fixing plate is fixed to the cylinder using bolts. The pressure-bearing steel plate connected below the steel columns remains in place to simulate the grouting and filling test of fractured coal and rock mass under this stress. The cylinder is made of high-strength rolled steel. An outer edge steel plate is pre-set at the top of the cylinder 8, with multiple bolt holes 7 corresponding to the bolts on the pressure-bearing fixing plate 1. The outer diameter of the rubber gasket is the same as the inner diameter of the cylinder, ensuring a tight fit between the rubber gasket and the cylinder during the compaction process.

[0035] In this embodiment, an exhaust hose valve 3 is installed inside the exhaust hose 16. On the one hand, it can remove air from the pores during grouting to reduce the pressure in the cylinder and make grouting easier. On the other hand, when grout flows out of the hole, it can be seen that the grouting is completed and the grout has filled the pores in the broken coal and rock mass.

[0036] The grouting system includes a grouting pipe 9, a grouting bend 14, a grouting tank 15, a grouting hose 16, and an air compressor 17 connected in sequence. Figure 4 As shown, a hole is opened at the bottom of the cylinder to connect to the grouting pipe of the grouting system. An extra section of the cylinder is left at the bottom to maintain the flatness of the device. After compaction, it can be connected to the grouting system to grout the crushed coal and rock mass. A grouting pipe valve 10 is installed on the grouting pipe 9. The valve closes when compacting the crushed coal and rock to prevent small-diameter crushed stones from leaking out. During grouting, the valve opens to fill the grouting mass. A grouting bend valve 12 is installed inside the grouting bend 14. One end of the grouting hose 16 is connected to the grouting tank 15, and the other end is connected to the air compressor 17. The size of the grouting pipe is slightly larger than the size of the grouting bend of the grouting system. The connection between the grouting pipe 9 and the grouting bend 14 is sealed with a sealing ring 13. The air compressor provides stable pressure to the grout in the grouting tank, thereby enabling the device to simulate the filling and reinforcement of goaf areas.

[0037] The method of using the crushed coal and rock mass compaction grouting device provided in this embodiment is as follows:

[0038] (1) Place the cylinder 8 on the servo machine in sequence, put the crushed coal and rock into the cylinder 8, and place the pressure fixing plate 1 into the cylinder. At this time, the exhaust hose valve 3 and the grouting pipe valve 10 are closed.

[0039] (2) The computer-controlled servo motor hydraulic rod applies a set load to the device to simulate the stress on the broken coal and rock mass in the goaf. The pressure can be set from 0 to 3 MPa.

[0040] (3) After loading is completed, the pressure fixing plate 1 and the cylinder 8 are fixed together by high-strength bolts 2 to fix the position of the pad and keep the pressure state of the crushed coal and rock mass unchanged at this time.

[0041] (4) such as Figure 1 As shown, the device is removed and placed on the support frame 11. The grouting pipe 9 is connected to the grouting bend 14 of the grouting system. The grouting bend is connected to the grouting hose 16. The other end of the grouting hose is connected to the grouting tank 15. The air compressor 17 is connected to the other end of the grouting tank via the grouting hose. After that, the exhaust hose valve 3, the grouting pipe 10, and the grouting bend valve 12 are opened. The air compressor is turned on to grout the compacted crushed coal and rock mass in the device. After the predetermined grouting effect is achieved, the grouting is stopped, and the sample is cured.

[0042] (5) After the grouting sample is cured, it is demolded and can be ground into a standard sample, numbered, so that subsequent mechanical tests can be carried out.

[0043] Example 2

[0044] In a typical embodiment of the present invention, a method for compaction grouting test of fractured coal and rock mass is proposed, comprising the following steps:

[0045] (1) Place the cylinder on the servo machine, put the crushed coal and rock into the cylinder, and put the whole assembly consisting of the pressure-bearing fixing plate and the pad wrapped with rubber pad into the cylinder. At this time, all valves are closed.

[0046] (2) Using computer-controlled servo motor hydraulic rods to apply a set load to the device to simulate the stress on the broken coal and rock mass in the goaf;

[0047] (3) After loading is completed, the pressure fixing plate is fixed to the cylinder with high-strength bolts to fix the position of the pad and keep the pressure state of the crushed coal and rock mass unchanged at this time;

[0048] (4) Remove the device and place it on the support frame. Grout the compacted broken coal and rock mass in the device through the grouting system. Stop grouting after the predetermined grouting effect is achieved, and cure the sample.

[0049] (5) After the grouting sample is cured, it is demolded and can be ground into a standard sample, numbered, so that subsequent mechanical tests can be carried out.

[0050] Furthermore, in step (2), the pressure loading range is 0-3MPa. In step (3), high-strength bolts are used to fix the position of the bearing plate. This allows the cylinder to be disassembled and placed on the support frame for grouting while maintaining the pressure state. It also allows subsequent maintenance and other work to be carried out while saving uniaxial compression test equipment.

[0051] The embodiments described above provide a detailed explanation of the technical solution of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test device for compaction grouting of fractured coal and rock mass, characterized in that, The device includes a pressure-bearing fixing plate and a cylinder. The pressure-bearing fixing plate is positioned above the cylinder and is bolted to the cylinder. Multiple steel columns are installed on the lower surface of the pressure-bearing fixing plate, with the length of each column exceeding the length of the bolts. A pad is connected below the steel columns, and the pad is wrapped with a rubber pad. An exhaust port is located in the center of the pad and connected to an exhaust hose. A grouting pipe is installed at the bottom of the cylinder and connected to a grouting system. The outer diameter of the rubber pad is the same as the inner diameter of the cylinder, ensuring a tight fit between the rubber pad and the cylinder during the compaction process. The bolts include multiple bolts, which are fixed to the lower surface of the pressure-bearing fixed plate by welding and are evenly arranged along the outer perimeter of the pressure-bearing fixed plate; the top of the cylinder is pre-set with an outer edge steel plate, and multiple bolt holes are provided on the outer edge steel plate, which correspond to the bolts on the pressure-bearing fixed plate; After loading is completed, the pressure-bearing fixing plate is fixed to the cylinder with high-strength bolts to fix the position of the pad and keep the pressure state of the crushed coal and rock mass unchanged.

2. The test device for compaction grouting of fractured coal and rock mass as described in claim 1, characterized in that, The grouting system includes a grouting pipe, a grouting bend, a grouting bucket, a grouting hose, and an air compressor connected in sequence.

3. The test device for compaction grouting of fractured coal and rock mass as described in claim 2, characterized in that, A grouting pipe valve is installed on the grouting pipe, and a grouting bend valve is installed on the grouting bend.

4. The test device for compaction grouting of fractured coal and rock mass as described in claim 2, characterized in that, The connection between the grouting pipe and the grouting bend is sealed with a sealing ring.

5. The test device for compaction grouting of fractured coal and rock mass as described in claim 1, characterized in that, An exhaust hose valve is installed inside the exhaust hose.

6. A method for compaction grouting test of fractured coal and rock mass, implemented using the test apparatus described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Place the cylinder on the servo machine, put the crushed coal and rock into the cylinder, and put the whole assembly consisting of the pressure fixing plate and the pad wrapped with rubber pad into the cylinder. At this time, all valves are closed. (2) Using computer-controlled servo motor hydraulic rods to apply a set load to the device to simulate the stress on the broken coal and rock mass in the goaf; (3) After loading is completed, the pressure fixing plate is fixed to the cylinder with high-strength bolts to fix the position of the pad and keep the pressure state of the crushed coal and rock mass unchanged at this time; (4) Remove the device and place it on the support frame. Grout the compacted broken coal and rock mass in the device through the grouting system. Stop grouting after the predetermined grouting effect is achieved, and cure the sample. (5) After the grouting sample is cured, it is demolded, ground into a standard sample, and numbered for subsequent mechanical tests.

7. The test method for compaction grouting of fractured coal and rock mass as described in claim 6, characterized in that, In step (2), the pressure loading range is 0-3 MPa.

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