Pebble bed grouting reinforcement device and method

Abstract

The invention discloses a pebble bed grouting reinforcement device and method, and belongs to the technical field of grouting reinforcement. The grouting head structure comprises a grouting outer pipe, an upper end plate and a lower end plate are arranged at the upper end and the lower end of the grouting outer pipe respectively, a through hole is formed in the middle of the upper end plate, a connecting sleeve is arranged in the middle of the inner side face of the lower end plate, a grouting inner pipe is arranged in the connecting sleeve, one end of the grouting inner pipe is connected into the connecting sleeve, and the other end of the grouting inner pipe is connected into the connecting sleeve. The other end of the grouting inner pipe penetrates out of the through hole of the upper end plate, a plurality of grout outlet holes are formed in the end, located in the grouting outer pipe, of the grouting inner pipe, an upper annular groove and a lower annular groove are formed in the outer side face of the lower end of the grouting outer pipe, and a mounting distance is formed between the upper annular groove and the lower annular groove. An upper annular sealing air bag and a lower annular sealing air bag are arranged in the upper annular groove and the lower annular groove respectively. The technical scheme is used for improving the grouting reinforcement effect of the pebble bed.

Description

Technical Field

[0001] The invention belongs to the technical field of grouting reinforcement, and in particular relates to a pebble layer grouting reinforcement device and method. Background Art

[0002] In the pebble layer, grouting reinforcement technology is an effective foundation treatment method, which improves the physical and mechanical properties of the soil layer by injecting slurry, thereby improving the bearing capacity and stability of the foundation.

[0003] In the prior art, when performing grouting operations, the existing grouting devices have the following problems: since the pebble layer is usually loose at the top and relatively dense at the bottom, when grouting is performed into the pebble layer through the grouting pipe, the slurry is usually injected into the loose surface layer, while the relatively dense pebble layer at a depth will not be injected with slurry or only a small amount of slurry will be injected, resulting in a poor grouting reinforcement effect on the pebble layer. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a pebble layer grouting reinforcement device and method, so as to improve the grouting reinforcement effect of the pebble layer.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: The present invention discloses a grouting reinforcement device for a pebble layer, comprising a grouting head structure, wherein the grouting head structure comprises a grouting outer tube, wherein the upper end and the lower end of the grouting outer tube are respectively provided with an upper end plate and a lower end plate, wherein the middle part of the upper end plate is provided with a through hole, and the middle part of the inner side surface of the lower end plate is provided with a connecting sleeve, wherein a grouting inner tube is arranged in the connecting sleeve, wherein one end of the grouting inner tube is connected to the connecting sleeve, and the other end of the grouting inner tube is arranged through the through hole of the upper end plate, wherein a plurality of grouting holes are arranged on one end of the grouting inner tube located inside the grouting outer tube, and an upper annular recess is arranged on the outer side surface of the lower end part of the grouting outer tube Groove and lower annular groove, an installation spacing is provided between the upper annular groove and the lower annular groove, an upper annular sealing airbag and a lower annular sealing airbag are respectively provided inside the upper annular groove and the lower annular groove, the upper annular sealing airbag and the lower annular sealing airbag are respectively fixed in the upper annular groove and the lower annular groove, at least one air inlet channel is provided in the wall thickness of the grouting outer tube, the upper annular sealing airbag and the lower annular sealing airbag are both connected to the air inlet channel, and a plurality of grouting holes are provided on the grouting outer tube between the upper annular airbag and the lower annular airbag; A partition plate is provided inside the grouting outer tube, and the partition plate is located above the grouting hole. The grouting hole is an inclined hole. A sealing rod is provided in the grouting hole, and one end of the sealing rod is slidably connected to the grouting hole, and the other end of the sealing rod is slidably connected to the partition plate and is located above the partition plate. A baffle rod is provided on the end of the sealing rod located above the partition plate, one end of the baffle rod is fixed on the sealing rod, and the other end of the baffle rod is arranged toward the inner wall of the grouting outer tube, an annular mounting shell is provided on the inner wall of the grouting outer tube below the baffle rod, and an annular pushing airbag is provided inside the annular mounting shell, and one end of the annular pushing airbag away from the baffle rod is fixed in the annular mounting shell and is communicated with the air inlet channel, and the other end of the annular pushing airbag is arranged toward the baffle rod.

[0006] Furthermore, it also includes a pumping pipe, a protective pipe and an air pipe. The pumping pipe is arranged inside the protective pipe. The wall thickness of the protective pipe is also provided with an air inlet channel that matches the position of the grouting outer pipe. One end of the protective pipe is fixed to the upper end of the grouting outer pipe. The pumping pipe is detachably connected to the end of the grouting inner pipe located outside the grouting outer pipe. The other end of the protective pipe is connected to the air pipe for inputting high-pressure gas into the air inlet channel.

[0007] Furthermore, the end of the pumping pipe is threadedly connected to the end of the grouting inner pipe.

[0008] Furthermore, a spring is sleeved on the blocking rod, one end of the spring is fixed to the partition plate, and the other end of the spring is fixed to the blocking rod. When the spring is not subjected to external force, the end of the blocking rod is located inside the grouting hole.

[0009] Furthermore, the annular mounting shell is arranged at an angle, and the opening end of the annular mounting shell is arranged at an angle pointing toward the blocking rod.

[0010] Furthermore, a hollow conical tip is provided below the lower end plate, a sealing plug is provided on the small diameter end of the conical tip, and the lower end plate is hollowed out.

[0011] A grouting method for a pebble layer grouting reinforcement device comprises the following steps: S1, assembling the protection pipe, pumping pipe, grouting head structure and gas pipe; S2, hoisting the assembled grouting head structure to a designated position in the grouting borehole; S3, input high-pressure air into the air transmission pipe to expand the upper annular sealing airbag, the lower annular sealing airbag and the annular push airbag. At this time, the upper annular airbag and the lower annular airbag are blocked in the grouting space above and below the grouting hole, so that only the pebble layer between the upper annular airbag and the lower annular airbag can be grouted. At the same time, the expansion of the annular push airbag will push the blocking rod, so that the grouting hole is connected with the inside of the grouting outer pipe; S4, inputting slurry into the pumping pipe, the slurry is discharged outward through the slurry outlet hole and the grouting hole, and grouting is performed to reinforce the pebble layer in the plugging area; S5, when the pebble layer at the designated position is grouted and solidified, the gas in the gas pipe is discharged, and the upper annular airbag, the lower annular airbag and the annular push airbag are reset, and then the grouting mechanism is lifted upward to the next grouting pebble layer area; S6, repeating steps S1-S5 until grouting is completed in each area of ​​the pebble layer.

[0012] The beneficial effects of the present invention are: In the present technical solution, when the grouting operation is performed on the pebble layer, the grouting area is sealed by expanding the upper annular sealing airbag and the lower annular sealing airbag, that is, after sealing, most of the slurry cannot penetrate to the outside of the upper annular sealing airbag and the lower annular sealing airbag, that is, only the pebble layer area between the upper annular airbag and the lower annular airbag can be penetrated and grouting can be performed, thereby ensuring the penetration of the slurry and the grouting effect of the area; that is, by performing layered grouting on the pebble layer, the grouting effect of the pebble layer in each grouting area can be guaranteed, thereby improving the grouting effect of the pebble layer as a whole, and there will be no problem that most of the grouting slurry penetrates into the loose part of the pebble layer, resulting in poor grouting effect in the relatively dense part.

[0013] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration: Figure 1 It is a three-dimensional schematic diagram of the grouting head structure in the pebble layer grouting reinforcement device of the present invention; Figure 2 A schematic cross-sectional view of a grouting head structure in a pebble layer grouting reinforcement device according to the present invention from one viewing angle; Figure 3 It is a schematic cross-sectional view of the grouting head structure in the pebble layer grouting reinforcement device of the present invention from another perspective; Figure 4 It is a schematic diagram of a front view and a cross-sectional view of a grouting head structure in a pebble layer grouting reinforcement device of the present invention; Figure 5 It is a schematic diagram of a side view and a cross-sectional view of a grouting head structure in a pebble layer grouting reinforcement device of the present invention; Figure 6It is a three-dimensional schematic diagram of the pebble layer grouting reinforcement device of the present invention; Figure 7 It is a schematic cross-sectional view of the pebble layer grouting reinforcement device of the present invention used for grouting of a pebble layer.

[0015] The following are marked in the accompanying drawings: 1. Grouting outer tube; 2. Lower end plate; 3. Upper end plate; 4. Conical tip; 5. Sealing plug; 6. Upper annular groove; 7. Upper annular sealing airbag; 8. Lower annular groove; 9. Lower annular sealing airbag; 10. Grouting hole; 11. Sealing rod; 12. Stop rod; 13. Annular mounting shell; 14. Annular push airbag; 15. Spring; 16. Grouting inner tube; 17. Slurry outlet hole; 18. Air inlet channel; 19. First connecting hole; 20. Second connecting hole; 21. Pebble layer; 22. Protective tube; 23. Pumping tube; 24. Connecting sleeve. DETAILED DESCRIPTION

[0016] like Figure 1 to Figure 7 As shown, a pebble layer grouting reinforcement device of the present invention comprises a grouting head structure, which comprises a grouting outer tube 1, wherein the upper end and the lower end of the grouting outer tube 1 are respectively provided with an upper end plate 3 and a lower end plate 2, a through hole is provided in the middle of the upper end plate 3, a connecting sleeve 24 is provided in the middle of the inner side surface of the lower end plate 2, a grouting inner tube 16 is provided in the connecting sleeve 24, one end of the grouting inner tube 16 is connected to the connecting sleeve 24, the ends of the connecting sleeve 24 and the grouting inner tube 16 can be welded or threaded, the other end of the grouting inner tube 16 passes through the through hole of the upper end plate 3 (this part can also be welded later), a plurality of slurry outlet holes 17 are provided on one end of the grouting inner tube 16 located inside the grouting outer tube 1, and the slurry outlet holes 17 are preferably evenly distributed in an annular manner, an upper annular groove 6 and a lower annular groove 8 are provided on the outer side surface of the lower end portion of the grouting outer tube 1, and the upper annular groove 6 and the lower annular groove 8 are provided on the upper annular groove 6 and the lower annular groove 8 are provided on the lower side surface of the lower end portion of the grouting outer tube 1. An installation spacing is provided between the lower annular grooves 8, and the installation spacing can be set according to actual conditions. An upper annular sealing airbag 7 and a lower annular sealing airbag 9 are respectively provided inside the upper annular groove 6 and the lower annular groove 8. The upper annular sealing airbag 7 and the lower annular sealing airbag 9 are respectively fixed in the upper annular groove 6 and the lower annular groove 8 (the contact parts are fixed, such as bonding). At least one air inlet channel 18 is provided in the wall thickness of the grouting outer tube 1. In the present specific embodiment, the number of the air inlet channels 18 is 2, and the upper annular sealing airbag 7 and the lower annular sealing airbag 9 are both connected to the air inlet channel 18. The connection method is that a first connecting hole 19 connected to the air inlet channel 18 is provided in the upper annular groove and the lower annular groove, and a plurality of grouting holes 10 are provided on the grouting outer tube 1 between the upper annular airbag and the lower annular airbag.

[0017] In one practicable manner, it also includes a pumping pipe 23, a protective pipe 22 and an air pipe. The pumping pipe 23 is arranged inside the protective pipe 22. The wall thickness of the protective pipe 22 is also provided with an air inlet channel 18 that matches the position of the grouting outer pipe 1. One end of the protective pipe 22 is fixed to the upper end of the grouting outer pipe 1. The pumping pipe 23 is detachably connected to the grouting inner pipe 16 at one end outside the grouting outer pipe 1. The other end of the protective pipe 22 is connected to the air pipe to input high-pressure gas into the air inlet channel 18. Of course, in actual use, equipment such as grouting pumps and air compressors will also be used. These are existing technologies and will not be elaborated on here.

[0018] The working principle of the above technical solution is: When grouting, the grouting components are lifted by a lifting machine and then lowered to a designated pebble layer 21 area in the grouting borehole, such as from the bottom of the grouting borehole (grouting borehole refers to the need to drill a hole from the ground to the underground pebble layer 21 before grouting, so as to facilitate the subsequent deep grouting of the underground pebble layer 21), and then high-pressure air is injected into the air inlet channel 18, that is, at this time, the upper annular sealing airbag 7 and the lower annular sealing airbag 9 will expand, and when expanded, they will be in close contact with the inner wall of the grouting borehole, thereby realizing a sealing operation, that is, after sealing, the slurry flowing out of the grouting hole 10 cannot penetrate the outer side of the upper annular sealing airbag 7 and the lower annular sealing airbag 9, that is, only the pebble layer 21 area between the upper annular airbag and the lower annular airbag can be penetrated and grouted, thereby ensuring the penetration of the slurry and the grouting effect of the area. After the grouting of this area is completed, the grouting head structure can be lifted upward, and then the next pebble layer 21 area is gradually grouted, and the grouting operation can be completed in this cycle.

[0019] In the above technical scheme, by performing layered grouting on the pebble layer 21, the grouting effect of the pebble layer 21 in each grouting area can be guaranteed, thereby improving the overall grouting effect of the pebble layer 21, and there will be no problem that most of the grouting slurry penetrates into the fluffy part of the pebble layer 21, resulting in poor grouting effect in the relatively dense part. At the same time, the upper annular groove 6 and the lower annular groove 8 are arranged so that the airbag is located within the wall thickness of the grouting outer tube 1 when it is not inflated, thereby avoiding the problem that it protrudes from the grouting outer tube 1 and causes friction damage to the inner wall of the grouting borehole, and increases the movement resistance of the grouting outer tube 1 in the grouting borehole.

[0020] In one practicable manner, the end of the pumping pipe 23 is threadedly connected to the end of the grouting inner pipe 16 for easy installation and removal. Of course, the protection pipe 22 can be connected to the grouting outer pipe 1 by welding or threading.

[0021] In one practicable manner, a partition plate is provided inside the grouting outer tube 1, and the edge of the partition plate is welded and fixed to the inner wall of the grouting outer tube 1, and the partition plate is located above the grouting hole 10, and the grouting hole 10 is an inclined hole, wherein one end of the axis passes through the middle of the partition plate, and a blocking rod 11 is provided in the grouting hole 10, and one end of the blocking rod 11 is slidably connected to the grouting hole 10, and the other end of the blocking rod 11 is slidably connected to the partition plate and is located above the partition plate, and a blocking rod 12 is provided on one end of the blocking rod 11 located above the partition plate, and one end of the blocking rod 12 is fixed to the blocking rod 1 1, the other end of the blocking rod 12 is arranged toward the inner wall of the grouting outer tube 1, an annular mounting shell 13 is arranged on the inner wall of the grouting outer tube 1 below the blocking rod 12, the inside of the annular mounting shell 13 is hollow, and one end close to the blocking rod 12 is opened, an annular mounting shell 13 is arranged inside the annular mounting shell 13, one end of the annular mounting shell 14 away from the blocking rod 12 is fixed in the annular mounting shell 13, and is communicated with the air inlet channel 18, and the communication method is that a second communicating hole 20 is arranged on the inner wall of the grouting outer tube 1, and the other end of the annular pushing airbag 14 is arranged toward the blocking rod 12.

[0022] That is, under normal circumstances, one end of the sealing rod 11 is located inside the grouting hole 10 to seal the grouting hole 10, thereby preventing the grouting hole 10 from being blocked by pebbles and soil when the grouting head structure is lowered into the grouting borehole. During grouting, the high-pressure air in the air inlet channel 18 will drive the annular sealing airbag to expand. Under the guidance of the annular mounting shell 13, the annular sealing airbag will push the blocking rod 12 when it expands, thereby driving the sealing rod 11 to slide out of the grouting hole 10, thereby facilitating subsequent grouting operations.

[0023] It is not difficult to understand that the blocking rod 11 is slidably connected to the partition plate, and a sealing structure similar to a telescopic sealing sleeve should be provided at the sliding connection portion (such as a flexible material made of a balloon in a cylindrical shape, which is sleeved on the blocking rod 11, with one end fixed on the blocking rod 11 and the other end fixed on the surface of the partition plate outside the blocking rod 11) to prevent slurry from entering the space above the partition plate.

[0024] In one feasible manner, a spring 15 is sleeved on the blocking rod 11, one end of the spring 15 is fixed on the partition plate, and the other end of the spring 15 is fixed on the blocking rod 12. When the spring 15 is not subjected to external force, the end of the blocking rod 11 is located inside the grouting hole 10. The setting of the spring 15 can provide resistance to the pebbles and soil outside the grouting hole 10 pushing the blocking rod 11, thereby preventing the soil from pushing the blocking rod 11 to move and causing the grouting hole 10 to be blocked. At the same time, after the annular push airbag 14 is reset, the blocking rod 11 can slide down and reset into the grouting hole 10.

[0025] It is easy to understand that the diameter of the blocking rod 11 can be slightly smaller than the diameter of the grouting hole 10, so that the end of the blocking rod 11 can enter the grouting hole 10 more easily, and the soil will not completely block the grouting hole 10.

[0026] In one feasible manner, the annular mounting shell 13 is tilted, and the open end of the annular mounting shell 13 is tilted toward the baffle rod 12, thereby guiding the expansion direction of the annular push airbag 14 so that it can act on the baffle rod 12. It is not difficult to understand that under the guidance of the partition plate, the sliding path of the blocking rod 11 is fixed, and thus it can be blocked in the grouting hole 10 after being reset.

[0027] In one feasible manner, a hollow conical tip 4 is provided below the lower end plate 2, and a sealing plug 5 is provided on the small diameter end of the conical tip 4. The lower end plate 2 is hollowed out, and by opening the sealing plug 5, the residual slurry inside the grouting head structure can be cleaned by injecting clean water, so that it is easy to reuse.

[0028] A grouting method for a pebble layer grouting reinforcement device comprises the following steps: S1, assembling the protection pipe 22, the pumping pipe 23, the grouting head structure and the gas pipe; S2, hoisting the assembled grouting head structure to a designated position in the grouting borehole; S3, input high-pressure air into the air pipe to expand the upper annular sealing airbag 7, the lower annular sealing airbag 9 and the annular pushing airbag 14. At this time, the upper annular airbag and the lower annular airbag are blocked in the grouting space above and below the grouting hole 10, so that only the pebble layer 21 between the upper annular airbag and the lower annular airbag can be grouted. At the same time, the expansion of the annular pushing airbag 14 will push the blocking rod 11, so that the grouting hole 10 is connected with the inside of the grouting outer tube 1; S4, input slurry into the pumping pipe 23, and the slurry is discharged outward through the slurry outlet hole 17 and the grouting hole 10, and the pebble layer 21 in the plugging area is grout-reinforced; S5, when the pebble layer 21 at the designated position is grouted and solidified, the gas in the gas pipe is discharged, and the upper annular airbag, the lower annular airbag and the annular push airbag 14 are reset, and then the grouting mechanism is lifted upward to the next grouting pebble layer 21 area; S6, repeating steps S1-S5 until grouting of each area in the pebble layer 21 is completed.

[0029] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A pebble layer grouting reinforcement device, characterized in that: The invention comprises a grouting head structure, wherein the grouting head structure comprises a grouting outer tube (1), wherein the upper end and the lower end of the grouting outer tube (1) are respectively provided with an upper end plate (3) and a lower end plate (2), wherein the middle part of the upper end plate (3) is provided with a through hole, and the middle part of the inner side surface of the lower end plate (2) is provided with a connecting sleeve (24), wherein a grouting inner tube (16) is provided inside the connecting sleeve (24), wherein one end of the grouting inner tube (16) is connected to the connecting sleeve (24), and the other end of the grouting inner tube (16) is arranged to pass through the through hole of the upper end plate (3), wherein one end of the grouting inner tube (16) located inside the grouting outer tube (1) is provided with a plurality of grouting holes (17), and an upper annular groove (6) and a lower annular groove (6) are provided on the outer side surface of the lower end of the grouting outer tube (1). shaped groove (8), an installation spacing is provided between the upper annular groove (6) and the lower annular groove (8), an upper annular sealing airbag (7) and a lower annular sealing airbag (9) are provided inside the upper annular groove (6) and the lower annular groove (8), respectively, the upper annular sealing airbag (7) and the lower annular sealing airbag (9) are fixed in the upper annular groove (6) and the lower annular groove (8), respectively, at least one air inlet channel (18) is provided in the wall thickness of the grouting outer tube (1), the upper annular sealing airbag (7) and the lower annular sealing airbag (9) are both connected to the air inlet channel (18), and a plurality of grouting holes (10) are provided on the grouting outer tube (1) between the upper annular airbag and the lower annular airbag; A partition plate is provided inside the grouting outer tube (1), and the partition plate is located above the grouting hole (10). The grouting hole (10) is an inclined hole. A blocking rod (11) is provided inside the grouting hole (10), and one end of the blocking rod (11) is slidably connected to the grouting hole (10). The other end of the blocking rod (11) is slidably connected to the partition plate and is located above the partition plate. A blocking rod (12) is provided on one end of the blocking rod (11) located above the partition plate, and one end of the blocking rod (12) is fixed to the blocking rod. On the rod (11), the other end of the blocking rod (12) is arranged toward the inner wall of the grouting outer tube (1), an annular mounting shell (13) is provided on the inner wall of the grouting outer tube (1) below the blocking rod (12), an annular pushing airbag (14) is provided inside the annular mounting shell (13), one end of the annular pushing airbag (14) away from the blocking rod (12) is fixed in the annular mounting shell (13) and communicated with the air inlet channel (18), and the other end of the annular pushing airbag (14) is arranged toward the blocking rod (12).

2. A pebble layer grouting reinforcement device according to claim 1, characterized in that: It also includes a pumping pipe (23), a protective pipe (22) and an air supply pipe, wherein the pumping pipe (23) is arranged inside the protective pipe (22), and an air intake passage (18) matching the position of the grouting outer pipe (1) is also provided in the wall thickness of the protective pipe (22), one end of the protective pipe (22) is fixed to the upper end of the grouting outer pipe (1), the pumping pipe (23) is detachably connected to one end of the grouting inner pipe (16) located outside the grouting outer pipe (1), and the other end of the protective pipe (22) is connected to the air supply pipe for inputting high-pressure gas into the air intake passage (18).

3. A pebble layer grouting reinforcement device according to claim 2, characterized in that: The end of the pumping pipe (23) is threadedly connected to the end of the grouting inner pipe (16).

4. The pebble layer grouting reinforcement device according to claim 1, characterized in that: A spring (15) is sleeved on the blocking rod (11), one end of the spring (15) is fixed to the partition plate, and the other end of the spring (15) is fixed to the blocking rod (12); when the spring (15) is not subjected to external force, the end of the blocking rod (11) is located inside the grouting hole (10).

5. The pebble layer grouting reinforcement device according to claim 1, characterized in that: The annular mounting shell (13) is arranged obliquely, and the opening end of the annular mounting shell (13) is arranged obliquely to point toward the blocking rod (12).

6. The pebble layer grouting reinforcement device according to claim 1, characterized in that: A hollow conical tip (4) is provided below the lower end plate (2), a sealing plug (5) is provided on the small diameter end of the conical tip (4), and the lower end plate (2) is hollowed out.

7. A grouting method for a pebble layer grouting reinforcement device according to any one of claims 1 to 6, characterized in that: The steps include: S1, assembling the protection pipe (22), the pumping pipe (23), the grouting head structure and the air delivery pipe; S2, hoisting the assembled grouting head structure to a designated position in the grouting borehole; S3, inputting high-pressure air into the air transmission pipe to expand the upper annular sealing airbag (7), the lower annular sealing airbag (9) and the annular pushing airbag (14), at which time the upper annular airbag and the lower annular airbag are blocked in the grouting space above and below the grouting hole (10), so that only the pebble layer (21) between the upper annular airbag and the lower annular airbag can be grouted, and at the same time, the expansion of the annular pushing airbag (14) will push the blocking rod (11), so that the grouting hole (10) is connected with the inside of the grouting outer tube (1); S4, inputting slurry into the pumping pipe (23), the slurry is discharged outward through the slurry outlet hole (17) and the grouting hole (10), and grouting is performed to reinforce the pebble layer (21) in the plugging area; S5, when the pebble layer (21) at the designated position is grouted and solidified, the gas in the gas pipe is discharged, and the upper annular airbag, the lower annular airbag and the annular push airbag (14) are reset, and then the grouting mechanism is lifted upward to the next grouting pebble layer (21) area; S6, repeating steps S1-S5 until grouting of each area in the pebble layer (21) is completed.

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