A hole sealing device for preventing hole collapse in gas extraction drilling in mines and a method for using the same

Abstract

The application relates to a hole sealing device for preventing hole collapse in gas extraction drilling in mines and a use method thereof, which comprises a gas extraction pipe, a sealing gasket and a first bag fixedly sleeved on the gas extraction pipe, a first grouting pipe fixedly and communicatively connected to the first bag, a second bag fixedly sleeved on the gas extraction pipe, the second bag being spaced from the first bag, and a second grouting pipe fixedly and communicatively connected to the second bag; a pipe slit type sleeve is further sleeved on the gas extraction pipe, the pipe slit type sleeve is a tubular structure with both ends being open, a strip-shaped through hole is formed in the pipe slit type sleeve, one end of the pipe slit type sleeve close to the sealing gasket is in abutment with the sealing gasket, a return grouting pipe is arranged in the pipe slit type sleeve, one end of the return grouting pipe close to the second bag is spaced from the second bag, a second grout leakage hole is formed in one side of the second bag close to the sealing gasket, and the second grouting pipe and the first grouting pipe penetrate through the pipe slit type sleeve. When the application is used for a long time, the sealing performance and safety of the drilling hole can be ensured, and the drilling hole collapse can be prevented.

Description

Technical Field

[0001] This invention belongs to the field of coal mining technology, and in particular relates to a sealing device for preventing collapse of mine boreholes used for gas extraction and its usage method. Background Technology

[0002] Coal is my country's main energy source, and gas drainage is one of the fundamental measures to prevent coal mine gas disasters. Currently, before gas drainage, borehole sealing is required. The traditional method for sealing boreholes involves using hollow, elastic gas bags. Specifically, the gas bag is fixed to a gas drainage pipe, which is then inserted into the borehole. Slurry is injected into the gas bag to inflate it. Once inflated, the gas bag presses against the borehole wall, supporting it and sealing the borehole. However, due to… During gas drainage, high-pressure gas needs to be injected into the borehole to displace the gas in the coal seam. This places high demands on the sealing performance and safety of the borehole. If only a gas bag is used to seal the borehole, the sealing performance will decrease over a long period of use. In addition, during gas drainage, due to the high degree of development of fractures around the borehole wall, the gas bag can only seal the borehole and cannot grout the fractures around the borehole wall. This will make it difficult to meet the sealing requirements during gas drainage and may easily cause borehole collapse. Therefore, the existing technology still has shortcomings and deficiencies. Summary of the Invention

[0003] The purpose of this invention is to provide a sealing device and its method for preventing collapse of mine boreholes used for gas extraction, in order to solve the problems mentioned in the background art.

[0004] The technical solution adopted by the present invention to solve the above problems is as follows:

[0005] A sealing device for preventing collapse of a gas extraction borehole in a mine, comprising a gas extraction pipe, the gas extraction pipe having a head end and a tail end, characterized in that: a sealing gasket made of flexible sealing material is fixedly sleeved at the tail end of the gas extraction pipe, a first bag is fixedly sleeved at the head end of the gas extraction pipe, the first bag being a hollow elastic structure, a first grouting pipe penetrating the sealing gasket is fixedly connected to the first bag, a second bag is also fixedly sleeved on the gas extraction pipe located between the first bag and the sealing gasket, the second bag being spaced apart from the first bag, the second bag also being a hollow elastic structure, a second grouting pipe penetrating the sealing gasket is fixedly connected to the second bag, and the first grouting pipe is located outside the second bag;

[0006] A slotted sleeve is fitted onto the gas extraction pipe located between the second bladder and the sealing gasket. The slotted sleeve is a tubular structure with open ends. A strip-shaped through hole of the same length as the slotted sleeve is opened on the slotted sleeve, and the end of the slotted sleeve near the sealing gasket abuts against the sealing gasket. A slurry return pipe is installed inside the slotted sleeve, penetrating the sealing gasket. The end of the slurry return pipe near the second bladder is spaced apart from the second bladder. A second slurry inlet is opened on the side of the second bladder near the sealing gasket. The second grouting pipe and the first grouting pipe respectively penetrate the slotted sleeve.

[0007] Furthermore, the outer wall of the slotted sleeve away from the sealing gasket has several leakage through holes.

[0008] Furthermore, the end of the slotted sleeve away from the sealing gasket is configured as a tapered structure, and the outer diameter of the tapered structure away from the sealing gasket is smaller than the outer diameter of the other end of the tapered structure.

[0009] Furthermore, the first slurry outlet is provided on the side of the first sac near the sealing gasket.

[0010] Furthermore, there are multiple first bags, which are equidistantly distributed along the length of the gas extraction pipe. Each first bag has a first grouting port on the side near the sealing gasket. Each first bag is fixedly connected to a first grouting pipe, which passes through multiple first bags, second bags and sealing gaskets in sequence and is located outside the sealing gasket.

[0011] Furthermore, a first sealing sleeve is installed at the end of the first grouting pipe away from the first bladder; a second sealing sleeve is installed at the end of the second grouting pipe away from the second bladder; and a third sealing sleeve is installed at the end of the return grouting pipe away from the second bladder.

[0012] Furthermore, the method of using the aforementioned sealing device for mine borehole gas drainage and anti-collapse holes includes the following steps:

[0013] Step 1: First, fix the first grouting bag connected to the first grouting pipe and the second grouting bag connected to the second grouting pipe onto the gas extraction pipe. The distance between the first grouting bag and the second grouting bag should be 5-10m. Second, install the slotted casing onto the gas extraction pipe and install a return grouting pipe inside the slotted casing. Finally, fix the sealing gasket onto the gas extraction pipe, pass the first grouting pipe through the second grouting bag and then through the sealing gasket, and then pass the second grouting pipe and the return grouting pipe through the sealing gasket respectively, and seal the penetration points on the sealing gasket.

[0014] Step 2: In the initial state, the outer diameter of the slotted casing is larger than the borehole diameter. Under the action of external force, the slotted casing needs to be embedded into the borehole. During the process of embedding the slotted casing into the borehole, the strip-shaped through holes on the slotted casing will shrink, causing the slotted casing to deform. After the slotted casing deforms, its outer wall will fit against the borehole wall. Then, the gas extraction pipe with the first and second bladders is inserted into the borehole after passing through the slotted casing, and the sealing gasket is located outside the borehole opening.

[0015] Step 3: Seal the opening of the drilled hole using a sealing gasket;

[0016] Step 4: Grout is injected into the second grouting bag through the second grouting pipe. When the second grouting bag is full of grout, it will adhere to the borehole wall. After the second grouting bag is full of grout, the grout in the second grouting bag will flow into the slotted casing and into the borehole between the slotted casing and the second grouting bag through the second grouting port until the grout flows out through the return grouting pipe. Grouting will continue for a period of time. Then, the second grouting pipe is sealed through the second sealing sleeve, and the return grouting pipe is sealed through the third sealing sleeve to complete the first sealing of the borehole.

[0017] Step 5: Grout is injected into the first grouting bag through the first grouting pipe. When the first grouting bag is full of grout, it will adhere to the borehole wall. When the first grouting bag is full of grout, a grouting space will be formed between the first grouting bag, the second grouting bag and the borehole. The grout in the first grouting bag will also flow into the grouting space through the first grouting port. When the grouting space is full of grout, the first grouting pipe is sealed through the first sealing sleeve to complete the second sealing of the hole.

[0018] Furthermore, in step four, when the slurry in the second bag flows into the slotted casing through the second slurry inlet, the slurry can flow into the fissures around the borehole wall through the seepage throughlet.

[0019] Furthermore, in step three, when the sealing gasket seals the opening of the drilled hole, a sealing agent is used to seal the opening of the drilled hole, and the sealing gasket is tightly attached to the opening of the drilled hole for sealing.

[0020] The beneficial effects of the present invention by adopting the above technical solution are as follows:

[0021] This invention, based on existing gas extraction pipes, also seals the borehole using a first and second bladder bag, and seals the borehole opening with a sealing gasket. Furthermore, it uses a slotted casing fitted onto the gas extraction pipe. Initially, the outer diameter of the slotted casing is larger than the borehole diameter, requiring external force to embed it into the borehole. Upon embedding, the slotted casing deforms, causing its outer wall to conform to the borehole wall, thus providing radial support. It can prevent borehole collapse; in addition, based on the sealing of the borehole by the first and second slurry bags, by opening a second grouting port on the second slurry bag, the grout can fill the slotted casing and the borehole between the slotted casing and the second slurry bag. This not only grouts the cracks around the borehole wall, but also reseals the borehole, thereby improving the sealing performance and safety of the borehole. Therefore, during long-term use, the present invention can ensure the sealing performance and safety of the borehole, and after the grout solidifies, it can also prevent borehole collapse. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

[0023] Figure 2 for Figure 1 A schematic diagram of the middle part of the device.

[0024] Reference numerals in the attached diagram: 1. Gas extraction pipe; 2. First sluice bag; 21. First grouting port; 3. Second sluice bag; 31. Second grouting port; 4. First grouting pipe; 41. First sealing sleeve; 5. Second grouting pipe; 51. Second sealing sleeve; 6. Slotted casing; 61. Strip-shaped through hole; 62. Seepage through hole; 63. Conical structure; 7. Sealing gasket; 8. Return grout pipe; 81. Third sealing sleeve; 9. Drill hole. Detailed Implementation

[0025] To make the objectives, technical solutions, and beneficial effects of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0026] like Figure 1 and Figure 2As shown, this invention provides a sealing device for a mine borehole gas drainage anti-collapse hole, including a gas drainage pipe 1, which has a head end and a tail end. A sealing gasket 7 made of flexible sealing material is fixedly fitted onto the tail end of the gas drainage pipe 1. Both the gas drainage pipe 1 and the flexible sealing material are existing technologies. The sealing gasket 7 is used to seal the borehole opening of the borehole 9. A first bag 2 is fixedly fitted onto the head end of the gas drainage pipe 1. The first bag 2 is a hollow elastic structure. A first grouting pipe 4, which penetrates the sealing gasket 7, is fixedly connected to the first bag 2. The first grouting pipe 4 is used to inject grout into the first bag 2, and when the first bag 2 is filled with grout and expanded, it can press against the borehole wall of the borehole 9 to seal it. A second bag 3 is fixedly fitted onto the gas extraction pipe 1 located between the first bag 2 and the sealing gasket 7. The second bag 3 is spaced apart from the first bag 2, with a distance of 5-10m between them. This distance can be selected based on the gas extraction borehole parameters, coal seam geological conditions, and the degree of fracture development around the borehole wall of borehole 9. The second bag 3 is also a hollow elastic structure. A second grouting pipe 5, which penetrates the sealing gasket 7, is fixedly connected to the second bag 3. The second grouting pipe 5 is used to inject grout into the second bag 3. When the second bag 3 is filled with grout and expanded, it can press against the borehole wall of borehole 9 to seal the borehole 9. The first grouting pipe 4 is located outside the second bag 3.

[0027] Furthermore, a slotted sleeve 6 is fitted onto the gas extraction pipe 1 located between the second bag 3 and the sealing gasket 7. The slotted sleeve 6 is a tubular structure with open ends. A strip-shaped through hole 61 of the same length as the slotted sleeve 6 is formed on the slotted sleeve 6, and the end of the slotted sleeve 6 near the sealing gasket 7 abuts against the sealing gasket 7. Specifically, in the initial state, the outer diameter of the slotted sleeve 6 is larger than the diameter of the borehole 9. The slotted sleeve 6 needs to be embedded into the borehole 9 under the action of external force. When the slotted sleeve 6 is embedded into the borehole 9, it will deform. After deformation, its outer wall will fit against the borehole wall of the borehole 9, which can provide radial support force to the borehole wall of the borehole 9, thereby preventing the borehole 9 from collapsing. Secondly, a return slurry pipe 8 that penetrates the sealing gasket 7 is provided inside the slotted sleeve 6. The end of the return slurry pipe 8 near the second bag 3 abuts against the second bag 7. The bags 3 are spaced apart, and the distance between the end of the return pipe 8 and the second bag 3 fluctuates within 0.2m. The second bag 3 has a second grout inlet 31 on the side near the sealing gasket 7. Specifically, after the grout fills the second bag 3, it can flow into the slotted sleeve 6 and the borehole 9 between the slotted sleeve 6 and the second bag 3 through the second grout inlet 31 until the grout flows out through the return pipe 8. After grouting continues for a period of time, the grout can fill the slotted sleeve 6 and the borehole 9 between the slotted sleeve 6 and the second bag 3. This can grout the cracks around the borehole wall of the borehole 9 and reseal the borehole 9, thereby improving the sealing performance and safety of the borehole 9. In addition, after the grout solidifies, it can also prevent the borehole 9 from collapsing. The second grouting pipe 5 and the first grouting pipe 4 respectively penetrate the slotted sleeve 6.

[0028] Based on the existing gas extraction pipe 1, the borehole 9 is sealed using the first bag 2 and the second bag 3. A sealing gasket 7 is installed to seal the borehole opening. A slotted sleeve 6 is fitted onto the gas extraction pipe 1. When the slotted sleeve 6 is embedded in the borehole 9, it deforms, and its outer wall adheres to the borehole wall, providing radial support and preventing borehole collapse. Furthermore, the first bag 2 and the second bag 3... Based on the sealing of borehole 9, by opening a second grout inlet 31 on the second bag 3, the grout can fill the slotted casing 6 and the borehole 9 between the slotted casing 6 and the second bag 3. This not only allows grouting of the cracks around the borehole wall of borehole 9, but also re-seales borehole 9, thereby improving the sealing performance and safety of borehole 9. Therefore, during long-term use, the present invention can ensure the sealing performance and safety of borehole 9, and when the grout solidifies, it can also prevent borehole 9 from collapsing.

[0029] Furthermore, such as Figure 2As shown, several seepage holes 62 are provided on the outer wall of the slotted casing 6 at the end away from the sealing gasket 7. Specifically, the length of the slotted casing 6 is 2~3m, and the length of the seepage holes 62 on the slotted casing 6 is 1~1.5m. The length of the slotted casing 6 can be selected according to the degree of development of the fractures around the borehole wall of the borehole 9 and the stability of the rock strata around the borehole 9. When in use, when the grout flows into the slotted casing 6, it can seep into the fractures around the borehole wall of the borehole 9 located at the position of the slotted casing 6 through the seepage holes 62 to seal the fractures around the borehole wall of the borehole 9, thus achieving a better sealing effect for the borehole 9.

[0030] To facilitate the insertion of the slotted casing 6 into the borehole 9, therefore, as Figure 2 As shown, the end of the slotted sleeve 6 away from the sealing gasket 7 is set as a tapered structure 63. The outer diameter of the tapered structure 63 away from the sealing gasket 7 is smaller than the outer diameter of the other end of the tapered structure 63. By setting the tapered structure 63, it is easy to embed the slotted sleeve 6 into the borehole 9.

[0031] Furthermore, such as Figure 1 As shown, the first slurry inlet 21 is provided on the side of the first slurry bag 2 near the sealing gasket 7. Specifically, in use, when the first slurry bag 2 and the second slurry bag 3 are opened, a grouting space is formed between them and the borehole 9. When the grout fills the first slurry bag 2, it can flow into the grouting space through the first grouting inlet 21, thereby grouting the cracks around the borehole wall of the borehole 9 at that location, and also sealing the borehole 9 to improve the sealing performance and safety of the borehole 9. In addition, when the grout solidifies, it can also prevent the borehole 9 from collapsing.

[0032] Furthermore, there are multiple first bags 2, which are equidistantly distributed along the length of the gas extraction pipe 1. Each first bag 2 has a first grouting port 21 on the side near the sealing gasket 7. Each first bag 2 is fixedly connected to a first grouting pipe 4. Each first grouting pipe 4 passes through multiple first bags 2, second bags 3 and sealing gasket 7 in sequence and is located outside the sealing gasket 7. Specifically, the number of first bags 2 can be determined according to the depth of the borehole 9 and the degree of development of cracks around the borehole wall of the borehole 9, so as to seal the borehole 9 multiple times, thereby improving the sealing performance of the borehole 9. During use, the multiple first bags 2 are used sequentially from the shallow part to the deep part of the borehole 9.

[0033] Furthermore, such as Figure 1As shown, a first sealing sleeve 41 is installed at the end of the first grouting pipe 4 away from the first bladder 2, and the first sealing sleeve 41 is used to seal the first grouting pipe 4; a second sealing sleeve 51 is installed at the end of the second grouting pipe 5 away from the second bladder 3, and the second sealing sleeve 51 is used to seal the second grouting pipe 5; a third sealing sleeve 81 is installed at the end of the return grouting pipe 8 away from the second bladder 3, and the third sealing sleeve 81 is used to seal the return grouting pipe 8.

[0034] Furthermore, the method of using the aforementioned sealing device for mine borehole gas drainage and anti-collapse holes includes the following steps:

[0035] Step 1: First, fix the first grouting bag 2, which is connected to the first grouting pipe 4, and the second grouting bag 3, which is connected to the second grouting pipe 5, onto the gas extraction pipe 1. The distance between the first grouting bag 2 and the second grouting bag 3 is 5-10m. This distance can be selected according to the gas extraction borehole parameters, coal seam geological conditions, and the degree of fracture development around the borehole wall 9 as determined in advance. Second, fit the slotted casing 6 onto the gas extraction pipe 1, and install the return grouting pipe 8 inside the slotted casing 6. Finally, fix the sealing gasket 7 onto the gas extraction pipe 1, and pass the first grouting pipe 4 through the second grouting bag 3 and then through the sealing gasket 7. Then, pass the second grouting pipe 5 and the return grouting pipe 8 through the sealing gasket 7 respectively, and seal the penetration position on the sealing gasket 7 to complete the assembly of the sealing device.

[0036] Step 2: After the sealing device is assembled, in the initial state, the outer diameter of the slotted casing 6 is larger than the borehole diameter of the borehole 9. Under the action of external force, the slotted casing 6 needs to be embedded into the borehole 9. During the process of the slotted casing 6 being embedded into the borehole 9, the strip-shaped through hole 61 on the slotted casing 6 will shrink, causing the slotted casing 6 to deform. After the slotted casing 6 deforms, its outer wall will fit against the borehole wall of the borehole 9. Then, the gas extraction pipe 1 with the first bag 2 and the second bag 3 is inserted into the borehole 9 after passing through the slotted casing 6, and the sealing gasket 7 is located outside the borehole opening of the borehole 9, thus completing the installation of the gas extraction pipe 1.

[0037] Step 3: After the gas extraction pipe 1 is installed, use the sealing gasket 7 to seal the opening of the borehole 9 to complete the sealing of the opening of the borehole 9.

[0038] Step 4: After the borehole opening of borehole 9 is sealed, grout is injected into the second grouting bag 3 through the second grouting pipe 5. When the second grouting bag 3 is full of grout, it will adhere to the borehole wall of borehole 9. After the second grouting bag 3 is full of grout, the grout in the second grouting bag 3 will flow through the second grouting port 31 into the slotted casing 6 and into the borehole 9 between the slotted casing 6 and the second grouting bag 3, until the grout flows out through the return grouting pipe 8. Grouting will continue for a period of time. Then, the second grouting pipe 5 is sealed through the second sealing sleeve 51, and the return grouting pipe 8 is sealed through the third sealing sleeve 81, completing the first sealing. At this time, since the grout has filled the slotted casing 6 and the borehole 9 between the slotted casing 6 and the second grouting bag 3, the cracks around the borehole wall of borehole 9 can be grouted, and borehole 9 can be sealed again, thereby improving the sealing performance and safety of borehole 9. In addition, when the grout solidifies, it can also prevent borehole 9 from collapsing.

[0039] Step 5: After the first sealing is completed, grout is injected into the first grouting bag 2 through the first grouting pipe 4. When the first grouting bag 2 is full of grout, it will adhere to the borehole wall of borehole 9. A grouting space will be formed between the first grouting bag 2, the second grouting bag 3, and borehole 9. The grout in the first grouting bag 2 will also flow into the grouting space through the first seepage port 21. When the grouting space is full, the first grouting pipe 4 is sealed through the first sealing sleeve 41, completing the second sealing. At this point, since the grout has been filled... Within the full grouting space, grout can be injected into the cracks around the borehole wall at this location, and borehole 9 can also be resealed, which can improve the sealing performance and safety of borehole 9. In addition, after the grout solidifies, it can also prevent borehole 9 from collapsing. Furthermore, after the first sealing is completed, you can either wait for the grout used in the first sealing to solidify before performing a second sealing, or you can carry out gas extraction operations first, and then perform a second sealing of borehole 9 after gas extraction for a period of time, which can increase the gas extraction output.

[0040] Furthermore, in step four, when the slurry in the second bag 3 flows into the slotted casing 6 through the second slurry inlet 31, the slurry can flow into the cracks around the borehole wall of the borehole 9 through the seepage throughlet 62. At this time, the cracks around the borehole wall of the borehole 9 located at the position of the slotted casing 6 will be sealed tightly to improve the sealing performance of the borehole 9. Moreover, after the slurry solidifies, it can also prevent the borehole 9 from collapsing.

[0041] Furthermore, in step three, when the sealing gasket 7 seals the opening of the drill hole 9, a sealing agent is used to seal the opening of the drill hole 9, and the sealing gasket 7 is tightly attached to the opening of the drill hole 9 for sealing.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for using a sealing device for a mine borehole gas drainage and anti-collapse hole, comprising a sealing device, the sealing device including a gas drainage pipe, the gas drainage pipe including a head end and a tail end, characterized in that: The gas extraction pipe is fixedly fitted with a sealing gasket made of flexible sealing material at its tail end, and a first bag is fixedly fitted at its head end. The first bag is a hollow elastic structure. A first grouting pipe that penetrates the sealing gasket is fixedly connected to the first bag. A second bag is also fixedly fitted on the gas extraction pipe located between the first bag and the sealing gasket. The second bag is spaced apart from the first bag. The second bag is also a hollow elastic structure. A second grouting pipe that penetrates the sealing gasket is fixedly connected to the second bag. The first grouting pipe is located outside the second bag. A slotted sleeve is fitted onto the gas extraction pipe located between the second bladder and the sealing gasket. The slotted sleeve is a tubular structure with open ends. A strip-shaped through hole of the same length as the slotted sleeve is opened on the slotted sleeve, and the end of the slotted sleeve near the sealing gasket abuts against the sealing gasket. A slurry return pipe is installed inside the slotted sleeve, penetrating the sealing gasket. The end of the slurry return pipe near the second bladder is spaced apart from the second bladder. A second slurry inlet is opened on the side of the second bladder near the sealing gasket. The second grouting pipe and the first grouting pipe respectively penetrate the slotted sleeve. The outer wall of the slotted sleeve away from the sealing gasket has several seepage holes. The first slurry outlet is provided on the side of the first bladder near the sealing gasket; A first sealing sleeve is installed at the end of the first grouting pipe away from the first bladder; a second sealing sleeve is installed at the end of the second grouting pipe away from the second bladder; and a third sealing sleeve is installed at the end of the return grouting pipe away from the second bladder. The method of using the sealing device includes the following steps: Step 1: First, fix the first grouting bag connected to the first grouting pipe and the second grouting bag connected to the second grouting pipe onto the gas extraction pipe. The distance between the first grouting bag and the second grouting bag should be 5-10m. Second, install the slotted casing onto the gas extraction pipe and install a return grouting pipe inside the slotted casing. Finally, fix the sealing gasket onto the gas extraction pipe, pass the first grouting pipe through the second grouting bag and then through the sealing gasket, and then pass the second grouting pipe and the return grouting pipe through the sealing gasket respectively, and seal the penetration points on the sealing gasket. Step 2: In the initial state, the outer diameter of the slotted casing is larger than the borehole diameter. Under the action of external force, the slotted casing needs to be embedded into the borehole. During the process of embedding the slotted casing into the borehole, the strip-shaped through holes on the slotted casing will shrink, causing the slotted casing to deform. After the slotted casing deforms, its outer wall will fit against the borehole wall. Then, the gas extraction pipe with the first and second bladders is inserted into the borehole after passing through the slotted casing, and the sealing gasket is located outside the borehole opening. Step 3: Seal the opening of the drilled hole using a sealing gasket; Step 4: Grout is injected into the second grouting bag through the second grouting pipe. When the second grouting bag is full of grout, it will adhere to the borehole wall. After the second grouting bag is full of grout, the grout in the second grouting bag will flow into the slotted casing and into the borehole between the slotted casing and the second grouting bag through the second grouting port until the grout flows out through the return grouting pipe. Grouting will continue for a period of time. Then, the second grouting pipe is sealed through the second sealing sleeve, and the return grouting pipe is sealed through the third sealing sleeve to complete the first sealing of the borehole. Step 5: Inject grout into the first grouting bag through the first grouting pipe; when the first grouting bag is full of grout, it will adhere to the borehole wall, and when the first grouting bag is full of grout, a grouting space will be formed between the first grouting bag, the second grouting bag and the borehole. The grout in the first grouting bag will also flow into the grouting space through the first grouting port. When the grouting space is full of grout, the first grouting pipe is sealed through the first sealing sleeve to complete the second sealing of the hole.

2. The method of using the sealing device for preventing collapse of a mine borehole gas extraction hole according to claim 1, characterized in that: The end of the slotted sleeve away from the sealing gasket is configured as a tapered structure, and the outer diameter of the tapered structure away from the sealing gasket is smaller than the outer diameter of the other end of the tapered structure.

3. The method of using the sealing device for preventing collapse of a mine borehole gas extraction hole according to claim 1, characterized in that: There are multiple first bags, which are equidistantly distributed along the length of the gas extraction pipe. Each first bag has a first grouting port on the side near the sealing gasket. Each first bag is fixedly connected to a first grouting pipe. Each first grouting pipe passes through multiple first bags, second bags and sealing gaskets in sequence and is located outside the sealing gasket.

4. The method of using a sealing device for preventing collapse of a mine borehole gas extraction hole according to claim 1, characterized in that: In step four, when the slurry in the second bag flows into the slotted casing through the second seepage port, the slurry can flow into the fissures around the borehole wall through the seepage through-hole.

5. The method of using a sealing device for preventing collapse of a mine borehole gas extraction hole according to claim 1, characterized in that: In step three, when the sealing gasket seals the opening of the drilled hole, the opening of the drilled hole is sealed with a sealing agent, and the sealing gasket is tightly attached to the opening of the drilled hole to achieve a seal.

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