Static fracturing method for mine use with capsule expansion tube

Abstract

The present invention discloses a mining capsule expansion tube type static fracturing method, which specifically relates to the field of mining and comprises the following steps: S1, dividing a working area; S2, positioning drilling; S3, grooving a drill rod; S4, connecting a pipeline; and S5, expanding and cutting the roof. The present invention achieves the purpose of fracturing roof coal and rock by designing an expansion tube and utilizing the expansion amount of the expansion tube. Since high-pressure liquid is in a closed state in the inner cavity of the expansion tube, there is no need to block the drill hole during the implementation process. Compared with the existing deep hole blasting technology, high-pressure water injection technology and carbon dioxide phase change fracturing technology, the method eliminates the need for blocking the drilling process, saves labor, and thus improves work efficiency.

Description

Technical Field

[0001] The present invention relates to the field of mining, in particular to a mining capsule expansion tube type static fracturing method. Background Art

[0002] Usually, as the mining face advances, the direct roof in the middle of the goaf will naturally collapse and fill the goaf. However, the goaf near the upper and lower ends of the chute (corner area) is supported by the unmined coal seam and will not collapse in time, forming a cantilever structure. The roof pressure in the corner area continues to increase, and roof accidents are very likely to occur, causing hidden dangers such as coal wall spalling, floor bulging or gas accumulation. Therefore, it is necessary to use the pre-cracking method to timely drop the corner roof and manage the roof pressure to ensure the safety of the working face. Summary of the Invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a mining capsule expansion tube type static fracturing method.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The mining capsule expansion tube static fracturing method specifically includes the following steps:

[0006] S1. Work area division: The roof of the upper and lower drifts is divided into three zones. Zone A is located in the corner area behind the end support, Zone B is located directly above the end support, and Zone C is located in the roadway roof in front of the end support. Zone A is the expansion cracking zone, and Zones B and C are pre-cracking zones.

[0007] S2. Positioning drilling: Use a drilling rig to drill holes at a certain angle to the roof near the end supports of the upper and lower drifts. The holes can be drilled in areas B and A above the end supports, or in area C of the roadway roof.

[0008] S3, Drill pipe grooving: replace the drill pipe with an annular grooving drill bit, cut an annular groove at the crack initiation position inside the drill hole to form a stress concentration area;

[0009] S4. Pipeline connection: According to the drilling length and expansion process requirements, push the expansion tubes into the drill hole individually or in series, and connect the expansion tubes to the pressurization system with a high-pressure rubber hose;

[0010] S5. Expansion and topping: Open the pressurization system and fill the expansion tube with high-pressure emulsion, and then complete the topping by the expansion tube's expansion and rupture.

[0011] Preferably, the drilling process in step S2 has the following corresponding parameters:

[0012] (1) Immediate roof thickness h: The vertical thickness of the immediate roof of the mining face is related to the properties of the roof rock layer and is usually 10-30m;

[0013] (2) Drilling inclination angle α: It is the angle between the drill hole and the horizontal plane, usually between 15° and 90°. When the roof thickness h is constant, the smaller the inclination angle, the greater the drilling depth l. When drilling for expansion fracture, in order to facilitate the placement of expansion tubes in the hole and minimize the drilling workload, the reasonable inclination angle range is between 30° and 45°.

[0014] (3) Drilling diameter d: Determined by the drill bit diameter. For fracturing holes, it needs to be 1.1-1.2 times the diameter of the expansion tube. The drilling diameter is usually between 80-120 mm.

[0015] (4) Drill hole distance m: the distance between two drill holes measured on the roof, reflecting the density of drill holes. The size selection in the expansion fracturing technology is related to the lithology of the roof;

[0016] (5) Borehole parallel spacing n: It is the minimum distance between the center lines of two boreholes and is one of the most important parameters of static fracturing, namely the thickness of the fracture top plate. It is determined by the borehole inclination α and the borehole distance m, n = msinα.

[0017] By adopting the above technical solution: using the existing cut top surface or adjacent drill hole as the free surface, the direction of the expansion cracking can be controlled, which is an engineering problem that has not been solved by the existing pre-cracking technology.

[0018] Preferably, the pressurizing system in step S4 specifically includes an emulsion tank, a large-flow plunger pump, an electric motor and a small-flow plunger pump. The large-flow plunger pump, the electric motor and the small-flow plunger pump are all installed on the top cover of the emulsion tank. The input ends of the large-flow plunger pump and the small-flow plunger pump are both connected to the input pipe running through the emulsion tank. A filter is provided on the input pipe. The output ends of the large-flow plunger pump and the small-flow plunger pump are both connected to the output pipe. The output pipe is a high-pressure rubber hose. The expansion pipe is connected to the emulsion tank through the output pipe, the duplex pump and the input pipe. A hydraulic reversing valve and a manual unloading valve are provided on the output pipe. The large-flow plunger pump and the small-flow plunger pump are respectively connected to the two liquid inlets of the hydraulic reversing valve. The two liquid outlets of the hydraulic reversing valve are respectively connected to the emulsion tank and the high-pressure overflow valve, the pressure gauge and the expansion pipe. The large-flow plunger pump and the small-flow plunger pump together constitute a duplex pump.

[0019] The above technical solution is adopted: the working medium of the pressurization system is emulsion. During pressurization, the emulsion is transported from the pump station to the expansion pipe, and during pressure relief, it returns to the pump station through the expansion pipe for recycling. After the surrounding rock is broken, the used medium will not leak into the external polluted environment. It is safe, clean and economical. A double pump and a multi-stage pressure adjustment control method are used in the pressurization system. The initial fluid supply is in a low-pressure and high-flow mode. At this time, the high-flow plunger pump is started alone. During expansion and pressure maintenance, it is in a high-pressure and low-flow mode. At this time, the small-flow plunger pump and the large-flow plunger pump are started synchronously, and the pressure of the high-pressure relief valve is adjustable, which is both environmentally friendly and energy-saving.

[0020] Preferably, the outside of the expansion tube is sequentially covered with a liquid injection inner sleeve and a tube locking outer sleeve, the expansion tubes are spliced together through joints at both ends, plugs are provided on the joints, and a steel wire rope is wrapped around the middle surface of the expansion tube.

[0021] The above technical solution is adopted: the length of the expansion tube is 4-10m, which is suitable for deep hole pre-cracking, and the working pressure can reach 80-100Mpa. In terms of structural design, it can be used alone or in series, and the series length can reach about 40m. Therefore, it not only ensures convenient transportation, but also has strong adaptability to the drilling depth. In order to make the expansion able to withstand ultra-high pressure, the structure and layout of the steel wire rope inside the expansion tube are reconstructed, and at the same time, the locking tube structure of the liquid injection inner sleeve and the locking tube outer sleeve is innovatively designed.

[0022] Preferably, when the wire rope helix angle α is 15°-30°, the wire rope limits the radial deformation of the expansion tube, and the radial deformation of the expansion tube is small. When the wire rope helix angle is 75°-90°, the wire rope is used to withstand axial force and deformation, and the radial deformation of the expansion tube increases.

[0023] Preferably, the outer side of the liquid injection inner sleeve and the inner side of the locking tube outer sleeve are both provided with chamfers, and the liquid injection inner sleeve and the locking tube outer sleeve are respectively provided with matching card slots, and the liquid injection inner sleeve and the locking tube outer sleeve are clamped together.

[0024] Preferably, in step S4, the expansion pipes are connected in series via joints, and then a plug is inserted into the joint of the expansion pipe at the outer end for sealing.

[0025] Preferably, the step S5 is specifically as follows:

[0026] S5.1, filling stage: the pressurizing system works, the dual pumps in the pressurizing system supply liquid simultaneously, the flow rate is large, and the emulsion quickly fills the expansion tube cavity;

[0027] S5.2, Initial support stage: Continue to fill the expansion tube with liquid, the pressure of the pressurized system gradually increases, and the expansion tube initially expands. This stage is from the time when the outer wall of the expansion tube contacts the drilled rock mass to the time when the pressure inside the expansion tube reaches the pressure of the first safety valve of the pump station.

[0028] S5.3, resistance increase stage: After the initial support stage, the first safety valve is unloaded, the high-flow plunger pump stops working, and the low-flow plunger pump in the duplex pump supplies fluid, causing the pressure in the expansion tube to continuously increase. The expansion pressure generated by the expansion tube also increases accordingly. The expansion pressure is transmitted from the outer wall to the surrounding rock. Under the action of this pressure, the surrounding rock of the borehole first cracks at the stress concentration point a. Subsequently, the number of cracks increases and the length of cracks continues to extend toward the free surface.

[0029] S5.4, pressure holding and cracking stage: When the pressure in the expansion pipe reaches the rated pressure of the pump station, the pump station is in the pressure holding state, and the pressure in the expansion pipe reaches the maximum value. At this time, the cracks in the rock mass are fully developed and the rock is cracked. The pressure holding time varies greatly depending on the rock properties.

[0030] S5.5. Roof fracture stage: When the cracks in the surrounding rock penetrate from the borehole to the free surface, this part of the roof falls off, the pressure in the expansion tube suddenly drops, and the roof cutting process is completed.

[0031] The above technical solution utilizes the expansion volume of the expansion tube to achieve the purpose of fracturing the roof coal rock. Since the high-pressure liquid is in a closed state in the inner cavity of the expansion tube, there is no need to block the drill hole during the implementation process. Compared with the existing deep hole blasting technology, high-pressure water injection technology and carbon dioxide phase change fracturing technology, the drilling plugging process is eliminated, labor is saved, and work efficiency is improved.

[0032] The beneficial effects of the present invention are:

[0033] 1. This invention utilizes the expansion capacity of the expansion tube to achieve the purpose of fracturing the roof coal rock. Since the high-pressure liquid is in a closed state in the inner cavity of the expansion tube, there is no need to block the drill hole during the implementation process. Compared with existing deep hole blasting technology, high-pressure water injection technology and carbon dioxide phase change fracturing technology, this method eliminates the need for blocking the drill hole, saves labor, and improves work efficiency.

[0034] 2. The present invention utilizes the existing top cut surface or adjacent drilled hole as the free surface to control the direction of the cracking, which is an engineering problem that has not been solved by existing pre-cracking technology;

[0035] 3. The expansion tube in this invention is 4-10m long and suitable for deep-hole pre-cracking. Its operating pressure can reach 80-100 MPa. Its structural design allows for single or tandem use, with a maximum tandem length of approximately 40m. This ensures convenient transportation and strong adaptability to drilling depths. To enable the expansion tube to withstand ultra-high pressures, the structure and arrangement of the steel wire rope inside the expansion tube have been redesigned, along with innovative designs for the inner injection sleeve and the outer locking sleeve.

[0036] 4. The working medium of the pressurizing system of the present invention is emulsion. When pressurizing, the emulsion is transported from the pump station to the expansion pipe, and when the pressure is released, it returns to the pump station through the expansion pipe for recycling. After the surrounding rock is broken, the used medium will not leak into the external polluted environment. It is safe, clean and economical. A double pump and a multi-stage pressure control method are used in the pressurizing system. The initial liquid supply is a low-pressure and high-flow mode, and the expansion and pressure maintenance is in a high-pressure and low-flow mode. The pressure of the high-pressure overflow valve is adjustable, which is both environmentally friendly and energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the working surface in the present invention;

[0038] Figure 2 Schematic diagram of the annular groove in the present invention;

[0039] Figure 3 This is a schematic diagram of the connection of the pressurizing system in the present invention;

[0040] Figure 4 Schematic diagram of the structure of the expansion tube in the present invention;

[0041] Figure 5 Schematic diagram of the expansion tube assembly of the present invention;

[0042] Figure 6 A partial view of the expansion tube in the present invention;

[0043] Figure 7 Schematic diagram of the pressurization system in the present invention.

[0044] Legend: 1. Expansion tube; 2. Lock tube outer sleeve; 3. Liquid injection inner sleeve; 4. Connector; 5. Plug; 6. Wire rope; 7. Emulsion tank; 8. Filter; 9. High-flow plunger pump; 10. Electric motor; 11. Low-flow plunger pump; 12. Hydraulic reversing valve; 13. High-pressure relief valve; 14. Manual unloading valve; 15. Pressure gauge. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0046] like Figure 1-7As shown, the mining capsule expansion tube static fracturing method includes an expansion tube 1 and a pressurizing system, and the expansion amount of the expansion tube 1 is used to achieve the purpose of fracturing the roof coal rock. Since the high-pressure liquid is in a closed state in the inner cavity of the expansion tube 1, there is no need to seal the borehole during implementation. Compared with the existing deep hole blasting technology, high-pressure water injection technology and carbon dioxide phase change fracturing technology, the sealing drilling process is eliminated, labor is saved, which means that work efficiency is improved. The outside of the expansion tube 1 is sequentially provided with an injection inner sleeve 3 and a locking tube outer sleeve 2. The expansion tubes 1 are spliced with each other through joints 4 at both ends, and a plug 5 is provided on the joint 4. A steel wire rope 6 is wrapped around the middle surface of the expansion tube 1, and the outer side of the injection inner sleeve 3 and the inner side of the locking tube outer sleeve 2 are both provided with chamfers. The injection inner sleeve 3 and the locking tube outer sleeve 2 are respectively provided with matching card slots, and the injection inner sleeve 3 and the locking tube outer sleeve 2 are clamped together. The pressurizing system includes an emulsion tank 7, a large-flow plunger pump 9, an electric motor 10 and a small The flow plunger pump 11, the large flow plunger pump 9, the motor 10 and the small flow plunger pump 11 are all installed on the top cover of the emulsion tank 7, the input ends of the large flow plunger pump 9 and the small flow plunger pump 11 are communicated with the input pipe set through the emulsion tank 7, the input pipe is provided with a filter 8 for filtering impurities in the emulsion, the output ends of the large flow plunger pump 9 and the small flow plunger pump 11 are communicated with the output pipe, the output pipe is a high-pressure rubber hose, the expansion pipe 1 is communicated with the emulsion tank 7 through the output pipe, the duplex pump and the input pipe, a hydraulic reversing valve 12 and a manual unloading valve 14 are provided on the output pipe, the large flow plunger pump 9 and the small flow plunger pump 11 are respectively connected to the two liquid inlets of the hydraulic reversing valve 12, the two liquid outlets of the hydraulic reversing valve 12 are respectively communicated with the emulsion tank 7 and the high-pressure relief valve 13, the pressure gauge 15 and the expansion pipe 1, the large flow plunger pump 9 and the small flow plunger pump 11 together constitute a duplex pump, which specifically includes the following steps:

[0047] S1. Work area division: The roof of the upper and lower drifts is divided into three zones. Zone A is located in the corner area behind the end support, Zone B is located directly above the end support, and Zone C is located in the roadway roof in front of the end support. Zone A is the expansion cracking zone, and Zones B and C are pre-cracking zones.

[0048] S2. Positioning drilling: Use a drilling rig to drill holes at a certain angle to the roof near the upper and lower drift end supports. The holes can be drilled in areas B and A above the end supports, or in area C of the roadway roof. The following parameters are used during the drilling process:

[0049] (1) Immediate roof thickness h: The vertical thickness of the immediate roof of the mining face is related to the properties of the roof rock layer and is usually 10-30m;

[0050] (2) Drilling inclination angle α: It is the angle between the drill hole and the horizontal plane, usually between 15° and 90°. When the roof thickness h is constant, the smaller the inclination angle, the greater the drilling depth l. When drilling for expansion fracture, in order to facilitate the placement of the expansion tube 1 in the hole and minimize the drilling workload, the reasonable inclination angle range is between 30° and 45°.

[0051] (3) Drilling diameter d: Determined by the drill bit diameter. For fracturing holes, it needs to be 1.1-1.2 times the diameter of the expansion tube 1. The drilling diameter is usually between 80-120 mm.

[0052] (4) Drill hole distance m: the distance between two drill holes measured on the roof, reflecting the drill hole density. The size selection in the expansion fracturing technology is related to the lithology of the roof;

[0053] (5) Borehole parallel spacing n: It is the minimum distance between the center lines of two boreholes and is one of the most important parameters of static fracturing, namely the thickness of the expansion roof. It is determined by the borehole inclination angle α and the borehole distance m, n =;

[0054] S3. Drill pipe grooving: An annular grooving drill bit is installed on the drill pipe to cut an annular groove at the crack initiation location inside the borehole, forming a stress concentration area. The existing cut top surface or adjacent borehole is used as the free surface to control the cracking direction. This is an engineering problem that has not been solved by existing pre-cracking technology.

[0055] S4. Pipeline connection: According to the drilling length and the requirements of the expansion cracking process, the expansion tubes 1 are pushed into the borehole individually or in series. When the expansion tubes 1 are used in combination, the expansion tubes 1 are connected in series through the joints 4. Then, the plug 5 is inserted into the joint 4 of the expansion tube 1 at the outer end for sealing. The expansion tube 1 is connected to the pressurized system with a high-pressure rubber hose. The expansion tube 1 is 4-10m long and is suitable for deep hole pre-cracking. The working pressure can reach 80-100Mpa. In terms of structural design, it can be used individually or in series, and the series length can reach about 40m. Therefore, it ensures convenient transportation and strong adaptability to the drilling depth. In order to enable the expansion to withstand ultra-high pressure, the structure and arrangement of the steel wire rope 6 inside the expansion tube 1 are reconstructed, and the locking structure of the injection inner sleeve 3 and the locking tube outer sleeve 2 is innovatively designed;

[0056] S5, expansion and top cutting: start the pressurization system, fill the expansion tube 1 with high-pressure emulsion, and then complete the top cutting by the expansion tube 1 bursting. Specifically:

[0057] S5.1, filling stage: the pressurizing system is working, the dual pumps in the pressurizing system supply liquid simultaneously, the flow rate is large, and the emulsion quickly fills the inner cavity of the expansion tube 1;

[0058] S5.2, initial support stage: Continue to fill the expansion tube 1 with liquid, gradually increase the pressure of the pressurized system, and the expansion tube will initially expand. This stage is called the initial support stage, from the time when the outer wall of the expansion tube contacts the drilled rock mass until the pressure inside the expansion tube reaches the pressure of the first safety valve of the pump station;

[0059] S5.3, resistance increase stage: After the initial support stage, the first safety valve is unloaded, the high-flow plunger pump 9 stops working, and the low-flow plunger pump 11 in the duplex pump supplies liquid, causing the pressure in the expansion tube to continuously increase. The expansion pressure generated by the expansion tube 1 also increases accordingly. The expansion pressure is transmitted from the outer wall to the surrounding rock. Under the action of this pressure, cracks first appear at point a where stress is concentrated. Subsequently, the number of cracks increases and the length of cracks continues to extend toward the free surface.

[0060] S5.4, pressure holding and cracking stage: When the pressure in the expansion pipe 1 reaches the rated pressure of the pump station, the pump station is in the pressure holding state, and the pressure in the expansion pipe 1 reaches the maximum value. At this time, the cracks in the rock mass are fully developed and the rock is cracked. The pressure holding time varies greatly depending on the rock properties.

[0061] S5.5, roof fracture stage: when the cracks in the surrounding rock penetrate from the borehole to the free surface, this part of the roof falls off, and the pressure in the expansion pipe 1 suddenly drops, completing the roof cutting process. The working medium of the pressurizing system is emulsion. During pressurization, the emulsion is transported from the pump station to the expansion pipe 1, and during pressure relief, it returns to the pump station from the expansion pipe 1 for recycling. After the surrounding rock breaks, the used medium will not leak to the external polluting environment. It is safe, clean and economical. A double pump and a multi-stage pressure control method are used in the pressurizing system. The initial fluid supply is in a low-pressure and high-flow mode. At this time, the high-flow plunger pump 9 is started separately. During expansion and pressure maintenance, it is in a high-pressure and low-flow mode. At this time, the small-flow plunger pump 11 is started synchronously with the large-flow plunger pump 9, and the pressure of the high-pressure relief valve 13 is adjustable, which is both environmentally friendly and energy-saving.

[0062] Among them, when the helix angle α of the wire rope 6 is 15°-30°, the wire rope 6 limits the radial deformation of the expansion tube 1, and the radial deformation degree of the expansion tube 1 is small. When the helix angle of the wire rope 6 is 75°-90°, the wire rope 6 is used to withstand axial force and deformation, and the radial deformation degree of the expansion tube 1 increases.

[0063] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A static fracturing method using a capsule expansion tube for mining, characterized in that: The specific steps include: S1. Work area division: The roof of the upper and lower drifts is divided into three zones. Zone A is located in the corner area behind the end support, Zone B is located directly above the end support, and Zone C is located in the roadway roof in front of the end support. Zone A is the expansion cracking zone, and Zones B and C are pre-cracking zones. S2. Positioning drilling: Use a drilling rig to drill holes at an inclined angle into the roof near the end supports of the upper and lower drifts. The holes should be drilled in areas B and A above the end supports or in area C of the roadway roof. S3, Drill pipe grooving: replace the drill pipe with an annular grooving drill bit, cut an annular groove at the crack initiation position inside the drill hole to form a stress concentration area; S4. Pipeline connection: According to the drilling length and expansion process requirements, push the expansion tubes into the drill hole individually or in series, and connect the expansion tubes to the pressurization system with a high-pressure rubber hose; S5, expansion and topping: start the pressurization system, fill the expansion tube with high-pressure emulsion, and then complete the topping by the expansion tube bursting. The specific steps of step S5 are as follows: S5.1, filling stage: the pressurizing system works, the dual pumps in the pressurizing system supply liquid simultaneously, the flow rate is large, and the emulsion quickly fills the expansion tube cavity; S5.2, Initial support stage: Continue to fill the expansion tube with liquid, the pressure of the pressurized system gradually increases, and the expansion tube initially expands. This stage is from the time when the outer wall of the expansion tube contacts the drilled rock mass to the time when the pressure inside the expansion tube reaches the pressure of the first safety valve of the pump station. S5.3, resistance increase stage: After the initial support stage, the first safety valve is unloaded, the high-flow plunger pump stops working, and the low-flow plunger pump in the duplex pump supplies fluid, causing the pressure in the expansion tube to continuously increase. The expansion pressure generated by the expansion tube also increases accordingly. The expansion pressure is transmitted from the outer wall to the surrounding rock. Under the action of this pressure, the surrounding rock of the borehole first cracks at the stress concentration point a. Subsequently, the number of cracks increases and the length of cracks continues to extend toward the free surface. S5.4, pressure holding and cracking stage: When the pressure in the expansion pipe reaches the rated pressure of the pump station, the pump station is in the pressure holding state, and the pressure in the expansion pipe reaches the maximum value. At this time, the cracks in the rock mass are fully developed and the rock is cracked. The pressure holding time varies greatly depending on the rock properties. S5.

5. Roof fracture stage: When the cracks in the surrounding rock penetrate from the borehole to the free surface, this part of the roof falls off, the pressure in the expansion tube suddenly drops, and the roof cutting process is completed.

2. The mining capsule expansion tube static fracturing method according to claim 1, characterized in that: The drilling process in step S2 has the following corresponding parameters: (1) Roof thickness h: the vertical thickness of the immediate roof of the mining face, which is related to the properties of the roof rock layer and is 10-30m; (2) Drilling inclination angle α: It is the angle between the drill hole and the horizontal plane, usually between 15° and 90°. When the roof thickness h is constant, the smaller the inclination angle, the greater the drilling depth l. When drilling for expansion fracture, in order to facilitate the placement of expansion tubes in the hole and minimize the drilling workload, the inclination angle range is between 30° and 45°. (3) Drilling diameter d: Determined by the drill bit diameter. For fracturing holes, it needs to be 1.1-1.2 times the diameter of the expansion tube. The drilling diameter is between 80-120 mm. (4) Drill hole distance m: the distance between two drill holes measured on the roof, reflecting the drill hole density. The size selection in the expansion fracturing technology is related to the lithology of the roof; (5) Borehole parallel spacing n: It is the minimum distance between the center lines of two boreholes and is one of the most important parameters of static fracturing, namely the thickness of the fracture top plate. It is determined by the borehole inclination α and the borehole distance m, n = msinα.

3. The mining capsule expansion tube static fracturing method according to claim 1, characterized in that: The pressurizing system in step S4 specifically includes an emulsion tank, a large-flow plunger pump, an electric motor and a small-flow plunger pump. The large-flow plunger pump, the electric motor and the small-flow plunger pump are all installed on the top cover of the emulsion tank. The input ends of the large-flow plunger pump and the small-flow plunger pump are both connected to the input pipe running through the emulsion tank. A filter is provided on the input pipe. The output ends of the large-flow plunger pump and the small-flow plunger pump are both connected to the output pipe. The output pipe is a high-pressure rubber hose. The expansion pipe is connected to the emulsion tank through the output pipe, the duplex pump and the input pipe. A hydraulic reversing valve and a manual unloading valve are provided on the output pipe. The large-flow plunger pump and the small-flow plunger pump are respectively connected to the two liquid inlets of the hydraulic reversing valve. The two liquid outlets of the hydraulic reversing valve are respectively connected to the emulsion tank and the high-pressure overflow valve, the pressure gauge and the expansion pipe. The large-flow plunger pump and the small-flow plunger pump together constitute a duplex pump.

4. The mining capsule expansion tube static fracturing method according to claim 1, characterized in that: The expansion tubes are sequentially covered with a liquid injection inner sleeve and a tube locking outer sleeve. The expansion tubes are connected to each other through joints at both ends. The joints are provided with plugs. A steel wire rope is wrapped around the middle surface of the expansion tubes.

5. The mining capsule expansion tube static fracturing method according to claim 4, characterized in that: When the wire rope helix angle α is 15°-30°, the wire rope limits the radial deformation of the expansion tube, and the radial deformation of the expansion tube is small. When the wire rope helix angle is 75°-90°, the wire rope is used to withstand axial force and deformation, and the radial deformation of the expansion tube increases.

6. The mining capsule expansion tube static fracturing method according to claim 1, characterized in that: The outer side of the liquid injection inner sleeve and the inner side of the locking tube outer sleeve are both provided with chamfers, and the liquid injection inner sleeve and the locking tube outer sleeve are respectively provided with matching card slots, and the liquid injection inner sleeve and the locking tube outer sleeve are clamped together.

7. The mining capsule expansion tube static fracturing method according to claim 4, characterized in that: In step S4, the expansion pipes are connected in series via joints, and then plugs are inserted into the joints of the expansion pipes at the outer ends for sealing.

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