Deep grouting plugging device for building pile foundation in karst field with water

Abstract

The application discloses a deep grouting plugging device for a building pile foundation in a karst site with water, which comprises a water pressure plug, a plurality of grouting units are arranged on the side of the water pressure plug, a smooth grouting unit is arranged below the water pressure plug, and the smooth grouting unit comprises, from bottom to top, a scraper assembly, a supplementary grouting assembly and a smoothing assembly. The grouting unit comprises a convex lens-shaped capsule, the capsule is filled with cement slurry, and a grouting needle tube extending in the horizontal direction is arranged at the center position of the capsule. The smooth grouting unit can effectively clean the burrs on the hole wall, provide the cement slurry to cover the hole wall and smooth the hole wall, so that the hole wall is smoother, the grouting unit can comprehensively grout the rock-soil body around the hole wall, and the strength, compactness and impermeability of the rock-soil body are improved. The technical problem that the plugging effect is poor due to the burrs on the rough hole wall and the loose rock-soil body around the hole wall in the prior art is solved.

Description

Technical Field

[0001] This invention belongs to the field of grouting reinforcement technology, specifically relating to a deep grouting sealing device for existing building pile foundations in water-bearing karst sites. Technical Background

[0002] Karst is a product of the interaction between water and soluble media. The karst process is essentially the erosion and transformation of soluble rock layers by groundwater. Especially for deep rock and soil masses, water with erosive capabilities dissolves soluble rocks, creating irregular caves in underground spaces. Karst phenomena hidden deep underground usually exist in a very concealed form, and current surveying methods make it difficult to determine their exact location and size during the geological exploration stage.

[0003] During construction, when karst caves exist in the underlying rock mass of the pile foundation, it not only affects the stability of the stratum strength but also has a significant impact on the bearing capacity of the pile foundation. However, this only becomes apparent after the project is completed and put into use, when uneven settlement or other safety issues occur in the building.

[0004] For the treatment of karst caves at the pile bottom in karst sites, the process typically involves drilling a hole from the top of the pile down to the bottom and through the cave. The hole runs vertically through the entire pile, and grout is injected to fill the cave. During grouting, the borehole above the cave needs to be sealed to prevent the grouting pressure from acting backward on the pile top raft or foundation, causing displacement or deformation. Currently, rubber water-filled plugs are commonly used in construction. Water is injected to expand the rubber and achieve a seal against the surrounding borehole wall. However, the intense disturbance during drilling makes the surrounding soil and rock relatively loose, and the rough borehole wall with burrs results in less than ideal sealing performance from the rubber water-filled plugs. Summary of the Invention

[0005] In view of this, the present invention aims to provide a deep grouting sealing device for existing building pile foundations in karst sites with water, so as to solve the technical problem that the sealing effect is poor due to the roughness of the borehole wall and the looseness of the surrounding rock and soil.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A deep grouting sealing device for existing building pile foundations in karst sites with water includes a water pressure bladder plug. Multiple grouting units are provided on the side of the water pressure bladder plug. A smooth grouting unit is provided below the water pressure bladder plug. The smooth grouting unit includes a scraper assembly, a grouting filling assembly, and a smoothing assembly arranged sequentially from bottom to top. The smooth grouting unit removes burrs from the borehole wall, provides cement grout to cover the borehole wall, and smooths it. Each grouting unit includes a convex lens-shaped capsule filled with cement grout. A grouting needle extending horizontally is located at the center of the capsule.

[0008] Furthermore, the free end of the grouting needle passes through a through hole on the surface of the capsule and protrudes. A sealing ring made of a highly elastic material is provided at the through hole. The outer side of the sealing ring is fixedly connected to the wall of the through hole, and the inner side of the sealing ring is pressed against the wall of the grouting needle. The grouting needle and the capsule are connected and sealed through the sealing ring.

[0009] Furthermore, both the inner surface of the sealing ring and the outer wall of the grouting needle are smooth surfaces. The sealing ring and the grouting needle can slide relative to each other under the action of external force, but this does not affect their sealing effect.

[0010] Furthermore, the free end of the grouting needle tube is provided with a cone head, which seals the free end of the grouting needle tube. The tube body of the grouting needle tube is covered with multiple flow holes, and when the capsule is in the initial state, all the flow holes are located inside the capsule.

[0011] Furthermore, the middle part of the water pressure bladder is provided with a grouting pipe extending along the drilling depth direction, and the water pressure bladder is sleeved on the outer wall of the grouting pipe.

[0012] Furthermore, the scraper assembly includes a fixing plate sleeved on the outer wall of the grouting pipe. The top and bottom of the fixing plate are provided with limiting plates concentric with the fixing plate. The outer diameter of the limiting plate is larger than the outer diameter of the fixing plate, and both the outer diameter of the limiting plate and the outer diameter of the fixing plate are smaller than the drilling diameter. An annular scraper is sleeved on the outer surface of the fixing plate. The annular scraper is slidably connected to the fixing plate in the vertical direction. The annular scraper is frustum-shaped and gradually expands outward from bottom to top. The outer diameter of the top surface of the annular scraper is consistent with the drilling diameter. An elastic reset member is provided between the annular scraper and the limiting plate located at the top of the fixing plate.

[0013] Furthermore, the grouting assembly includes a grouting ring and a grout storage ring sleeved on the outer wall of the grouting pipe. The grout storage ring is located above the grouting ring and is connected to the grouting ring. The grouting ring is hollow and its outer diameter is the same as the borehole diameter. Multiple grout outlet holes are opened circumferentially at the bottom of the outer wall of the grouting ring. A connecting ring concentric with the grouting ring is provided inside the grouting ring. Multiple sealing rods are distributed circumferentially on the outer surface of the connecting ring. A sealing plate is provided at the end of the sealing rod away from the connecting ring. The sealing plate enables the opening and closing of the grout outlet holes. Multiple connecting rods are provided between the connecting ring and the annular scraper.

[0014] Furthermore, the smoothing assembly includes a smoothing ring and a recovery ring fitted onto the outer wall of the grouting pipe. The outer diameter of the smoothing ring is the same as the diameter of the drill hole. The recovery ring is located below the smoothing ring. The recovery ring is frustum-shaped and hollow inside. The top surface diameter of the recovery ring is the same as the diameter of the drill hole, and the top surface of the recovery ring is in contact with the bottom surface of the smoothing ring. Multiple recovery holes are provided circumferentially on the outer side wall of the recovery ring. The recovery ring is connected to the grout storage ring.

[0015] The beneficial effects of this invention are as follows:

[0016] (1) Compared with the existing technology, by setting up scraper assembly, grouting assembly and smoothing assembly, on the one hand, the burrs on the hole wall can be cleaned to prevent the burrs from damaging the water pressure bladder and affecting the normal use of the water pressure bladder. On the other hand, by grouting and smoothing the hole wall, the hole wall can be made smoother, so that the water pressure bladder will be in closer contact with the hole wall after water injection and expansion, thereby improving the sealing effect.

[0017] (2) By setting up the grouting unit, on the one hand, the rock and soil around the borehole wall can be fully grouted. The grout fills the pores and cracks in the rock and soil and consolidates the rock and soil, thereby improving the strength, density and impermeability of the rock and soil around the borehole wall. This prevents the grout from penetrating the rock and soil around the borehole wall and carrying away the fine particles in the rock and soil under the action of grouting pressure, causing the pores to continuously increase, the borehole wall to deform and break, and the sealing to fail. On the other hand, the grouting needle extends into the rock and soil around the borehole wall and plays a reinforcing role, which is conducive to improving the physical and mechanical properties of the rock and soil around the borehole wall. Attached Figure Description

[0018] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0019] Figure 1 This is a schematic diagram of the overall structure of a deep grouting sealing device for existing building pile foundations in a karst site with water, according to Embodiment 1 of the present invention.

[0020] Figure 2This is a schematic diagram of the scraper assembly, grouting assembly, and smoothing assembly in Embodiment 1 of the present invention;

[0021] Figure 3 for Figure 2 Enlarged view at point A1;

[0022] Figure 4 This is a cross-sectional view of the fixing plate in Embodiment 1 of the present invention;

[0023] Figure 5 for Figure 4 Enlarged view at point A2;

[0024] Figure 6 This is a schematic diagram of the limiting protrusion in Embodiment 1 of the present invention;

[0025] Figure 7 This is a schematic diagram of the internal structure of the grouting ring in Embodiment 1 of the present invention;

[0026] Figure 8 for Figure 7 Enlarged view at point A3;

[0027] Figure 9 This is a cross-sectional view of the grouting unit in Embodiment 1 of the present invention;

[0028] Figure 10 for Figure 9 Enlarged view at A4 in the middle.

[0029] The following labels are shown in the attached diagram:

[0030] 1. Grouting pipe; 2. Water pressure bladder plug; 21. Grouting unit; 22. Capsule; 23. Grouting needle tube; 24. Cone head; 25. Pad; 26. Sealing ring; 27. Flow hole; 3. Scraper assembly; 31. Fixing plate; 311. Limiting groove; 32. Limiting plate; 33. Annular scraper; 331. Limiting protrusion; 34. Elastic reset component; 35. Connecting rod; 4. Grouting assembly; 41. Grouting ring; 411. Grout outlet hole; 42. Connecting ring; 43. Sealing rod; 44. Sealing plate; 45. Grout storage ring; 46. Connecting pipe; 5. Smoothing assembly; 51. Smoothing ring; 52. Recovery ring; 521. Detailed Implementation

[0031] Example 1, see details Figures 1-10 .

[0032] like Figure 1 As shown, a deep grouting sealing device for existing building pile foundations in karst sites with water includes a water pressure bladder 2, multiple grouting units 21 located on the side of the water pressure bladder 2, and a smooth grouting unit located below the water pressure bladder 2.

[0033] The water pressure bladder 2 is sleeved on the outer wall of the grouting pipe 1. The water pressure bladder 2 is made of a highly elastic material (such as rubber), and its interior is hollow to hold liquid. The length of the water pressure bladder 2 is greater than twice its outer diameter. A water filling pipe is connected to the top of the water pressure bladder 2. The water filling pipe extends along the depth of the hole to the ground and is connected to a water pressure pump (not shown in the figure). Liquid is injected into the water pressure bladder 2 by the water pressure pump to make it expand.

[0034] In this embodiment, a hole is drilled from the top of the pile down to below the pile bottom and through the karst cave. The borehole runs vertically through the entire pile. The pile itself is made of cast concrete, which has high strength and good overall uniformity. The drill rod is unlikely to disturb the concrete around the borehole wall, resulting in a smooth borehole wall. However, the drilling process disturbs the soil and rock around the borehole wall, making it loose and the borehole wall rough with burrs. Even when the water pressure plug 2 is pressed against the borehole wall under water pressure, the burrs prevent a tight contact between the borehole wall and the water pressure plug 2, leaving gaps through which the grout can seep upwards. Furthermore, the grout, under the grouting pressure, carries away fine particles from the loose soil and rock around the borehole wall, causing the pores to continuously enlarge, the borehole wall to deform and break down, and the sealing to fail. In addition, the sharp and pointed burrs on the water pressure plug 2 can damage it, leading to leaks and other adverse consequences.

[0035] In this embodiment, a smooth grouting unit is provided below the water pressure bladder plug 2, such as... Figures 1-3 As shown, the smooth grouting unit includes a scraper assembly 3, a grouting and filling assembly 4, and a smoothing assembly 5 arranged sequentially from bottom to top. The scraper assembly 3 includes a fixing plate 31 sleeved on the outer wall of the grouting pipe 1. The inner side of the fixing plate 31 is welded to the outer wall of the grouting pipe 1. Limiting plates 32 are provided at the top and bottom of the fixing plate 31. The limiting plates 32 are also sleeved on the outer wall of the grouting pipe 1. The limiting plates 32 and the fixing plate 31 are fixedly connected by vertical threads and bolts. It should be noted that the outer diameter of the limiting plate 32 is larger than the outer diameter of the fixing plate 31. An annular scraper 33 is sleeved on the outer surface of the fixing plate 31. In this embodiment, the outer surface of the fixing plate 31 has an opening such as... Figure 4 , Figure 5 The limiting groove 311 shown has a groove welded to the inner side of the annular scraper 33, as shown. Figure 6The limiting protrusion 331 shown enables the fixed plate 31 and the annular scraper 33 to slide vertically together via the limiting groove 311 and the limiting protrusion 331. In this embodiment, the annular scraper 33 is generally frustum-shaped with a hollow interior. Its bottom surface coincides with the top surface of the limiting plate 32, and it gradually expands outward from bottom to top. The size of its top surface is consistent with the diameter of the drill hole. Multiple elastic reset members 34 are provided between the annular scraper 33 and the limiting plate 32. The elastic reset members 34 are located within the projection range of the limiting plate 32 onto the annular scraper 33. In this embodiment, the elastic reset members 34 are springs. One end of the elastic reset member 34 is welded to the top surface of the annular scraper 33, and the other end of the elastic reset member 34 is welded to the bottom surface of the limiting plate 32 above it.

[0036] With the scraper assembly 3 in place, during the downward movement, the annular scraper 33, which contracts inward at the bottom, can squeeze the burrs on the hole wall through its outer surface, causing the burrs on the hole wall to move inward and retract into the surrounding rock and soil, rather than simply scraping off the burrs. This ensures the integrity of the hole wall and is beneficial for subsequent grouting and smoothing.

[0037] The grouting assembly 4 includes a grouting ring 41 fitted onto the outer wall of the grouting pipe 1. The inner wall of the grouting ring 41 is welded to the outer wall of the grouting pipe 1, and the outer wall of the grouting ring 41 is columnar with a diameter consistent with the borehole diameter. The grouting ring 41 is hollow, and multiple grout outlet holes 411 are opened at the bottom of its outer wall, and the multiple grout outlet holes 411 are evenly distributed along the circumference. Figure 2 As shown, multiple connecting rods 35 are evenly distributed along the circumferential direction on the outer edge of the top surface of the annular scraper 33. The connecting rods 35 are in a continuous bent shape. One end of the connecting rod 35 is welded to the top surface of the annular scraper 33 in the vertical direction, and the other end of the connecting rod 35 passes through the bottom plate of the grouting ring 41 in the vertical direction and extends into the internal space of the grouting ring 41. It should be noted that the connection between the connecting rod 35 and the bottom plate of the grouting ring 41 is sealed (such as with sealant) to prevent grout from leaking from the connection.

[0038] like Figure 7 , Figure 8As shown, the grouting ring 41 has a connecting ring 42 concentric with it inside. The inner diameter of the connecting ring 42 is larger than the outer diameter of the grouting pipe 1, and the outer diameter of the connecting ring 42 is smaller than the inner diameter of the grouting ring 41. The bottom surface of the connecting ring 42 is welded to the end face of the connecting rod 35 that extends into the grouting ring 41. Multiple sealing rods 43 are distributed circumferentially on the outer surface of the connecting ring 42. One end of the sealing rod 43 is welded to the outer surface of the connecting ring 42, and the other end of the sealing rod 43 is welded to a sealing plate 44. The sealing plate 44 is larger than the grout outlet hole 411 and can seal the grout outlet hole 411. A grout storage ring 45 is also provided above the grouting ring 41. Similarly, the grout storage ring 45 is fitted onto the outer wall of the grouting pipe 1 and is hollow inside, used to store cementitious grout (such as cement grout). In this embodiment, the top plate of the grouting ring 41 is in close contact with the bottom plate of the grout storage ring 45, and a through hole (not shown in the figure) is provided between the two, so that the grouting ring 41 is replenished in real time through the grout storage ring 45.

[0039] It should be further explained that, on the one hand, in this embodiment, when the annular scraper 33 is in its initial position, that is, when the bottom surface of the annular scraper 33 is at the same horizontal plane as the bottom surface of the fixed plate 31, the sealing plate 44 precisely seals the grout outlet 411; when the annular scraper 33 slides upward under the action of external force, the connecting rod 35 drives the connecting ring 42, the sealing rod 43, and the sealing plate 44 to move upward, thereby opening the grout outlet 411, and the grout inside the grouting ring 41 flows out along the grout outlet 411 and covers the hole wall. On the other hand, the grouting of the grouting component 4 is selective. In this embodiment, part of the borehole is located inside the pile body, and part is located in the rock and soil at the bottom of the pile. For the pile body, its hole wall is smooth and burr-free, and the concrete around the hole wall has high strength and good stability. During the downward movement, the annular scraper 33 will not slide vertically, so the grout outlet 411 is always in a closed state, thereby saving grout and avoiding waste. For the soil and rock mass at the pile bottom, the borehole wall is rough and has burrs. During the downward movement, the annular scraper 33 is resisted by the surrounding burrs and moves vertically upward, thereby driving the grouting component 4 to continuously discharge grout, covering the borehole wall. By adjusting the grout discharge timing according to the change in borehole wall roughness, the rational utilization of grout is ensured.

[0040] like Figure 2As shown, the smoothing component 5 includes a smoothing ring 51 fitted onto the outer wall of the grouting pipe 1. The inner wall of the smoothing ring 51 is welded to the outer wall of the grouting pipe 1. The outer wall of the smoothing ring 51 is cylindrical, and its diameter is the same as the borehole diameter. A hollow recovery ring 52 is provided below the smoothing ring 51. The recovery ring 52 is also fitted onto the outer wall of the grouting pipe 1. The recovery ring 52 is frustum-shaped, with its bottom diameter smaller than its top diameter, and its top surface is in contact with the bottom surface of the smoothing ring 51. It should be noted that in this embodiment, multiple recovery holes 521 are evenly distributed along the circumference on the outer wall of the recovery ring 52. Multiple vertical connecting pipes 46 are evenly distributed on the bottom surface of the recovery ring 52 near the inner ring of the grouting pipe 1. The top end of the connecting pipe 46 communicates with the smoothing ring 51, and the bottom end of the connecting pipe 46 communicates with the grout storage ring 45. During the downward movement, the slurry on the borehole wall is smoothed by the smoothing ring 51. Excess slurry can enter the recovery ring 52 through the recovery hole 521. The slurry in the recovery ring 52 flows into the slurry storage ring 45 through the connecting pipe 46, thereby realizing the recycling of excess slurry and achieving the effect of saving resources.

[0041] The above technical solution can, on the one hand, clean the burrs on the hole wall to prevent them from damaging the water pressure bladder plug 2 and affecting its normal use; on the other hand, by filling and smoothing the hole wall with slurry, the hole wall can be made smoother, so that the water pressure bladder plug 2 will have a tighter contact with the hole wall after it expands with water, thereby improving the sealing effect.

[0042] like Figure 1 As shown, the side of the water pressure bladder 2 is provided with multiple grouting units 21 along the circumferential direction from top to bottom. In this embodiment, the grouting unit 21 includes a capsule 22 in the shape of a convex lens. The capsule 22 is made of rubber material, and the bottom surface of the capsule 22 is arc-shaped and closely attached to the side of the water pressure bladder 2. The two can be attached by adhesive. Figure 9 As shown, a horizontally extending grouting needle tube 23 is provided at the center of the capsule 22. One end of the grouting needle tube 23, near the grouting pipe 1, is fixedly connected to the inner surface of the capsule 22's base plate via a pad 25. The pad 25 is integrally formed with the capsule 22, and its surface has a groove corresponding to the grouting needle tube 23. The bottom end of the grouting needle tube 23 extends into the groove for fixation. The pad 25 effectively prevents stress concentration at the end of the grouting needle tube 23 from damaging the capsule 22.

[0043] The end of the grouting needle tube 23 away from the grouting tube 1 passes through a through hole on the surface of the capsule 22 and protrudes therefrom. The through hole is provided with... Figure 10The sealing ring 26 shown is made of a highly elastic rubber material (such as high cis-butadiene rubber). The outer side of the sealing ring 26 is bonded to the wall of the through hole, and the inner side of the sealing ring 26 is pressed against the wall of the grouting needle tube 23. The sealing ring 26 achieves the connection and sealing between the grouting needle tube 23 and the capsule 22. It is worth noting that in this embodiment, both the inner side of the sealing ring 26 and the outer wall of the grouting needle tube 23 are smooth surfaces. They can slide relative to each other under the action of external force, but this does not affect the sealing effect of both.

[0044] The free end of the grouting needle tube 23 is provided with a cone head 24, which is integrally formed with the grouting needle tube 23. The tube body of the grouting needle tube 23 is covered with multiple flow holes 27. It should be noted that when the capsule 22 is in the initial state, that is, the capsule 22 does not come into contact with the hole wall and the capsule 22 is not subjected to external force, the flow holes 27 are all located in the internal space of the capsule 22.

[0045] When the water pressure bladder 2 expands continuously under water pressure, firstly, the cone 24 at the free end of the grouting needle tube 23 enters the borehole wall; then, the borehole wall contacts and abuts against the surface of the capsule 22 and compresses the capsule 22 in the horizontal direction, thereby causing the sealing ring 26 to slide along the tube body, so that the flow hole 27 near the cone 24 end is exposed outside the capsule 22. At the same time, the cementitious slurry (such as cement slurry) contained inside the capsule 22 enters the grouting needle tube 2 through the flow hole 27 under pressure and passes through the tube body and is discharged from the flow hole 27 near the cone 24 end. The discharged slurry fills and reinforces the rock and soil around the borehole wall; finally, as the slurry in the capsule 22 is completely squeezed out, the grouting and reinforcement process of the grouting unit 21 ends.

[0046] When the water pressure plug 2 reaches the designated position for water injection and sealing, the grouting unit 21 can, on the one hand, comprehensively grout the rock and soil around the borehole wall. The grout fills the pores and fissures in the rock and soil and consolidates the rock and soil, thereby improving the strength, density and impermeability of the rock and soil around the borehole wall. This prevents the grout from penetrating the rock and soil around the borehole wall and carrying away fine particles in the rock and soil under the action of grouting pressure, which would cause the pores to continuously increase, the borehole wall to deform and break, and the sealing to fail. On the other hand, the grouting needle 23 extends into the rock and soil around the borehole wall and plays a reinforcing role, thereby improving the physical and mechanical properties of the rock and soil around the borehole wall.

[0047] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended 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 to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A deep grouting sealing device for existing building pile foundations in karst sites with water, comprising a water pressure bladder, characterized in that, The side of the hydraulic bladder plug is provided with multiple grouting units, and a smooth grouting unit is provided below the hydraulic bladder plug. The smooth grouting unit includes a scraper assembly, a grouting component, and a smoothing component arranged sequentially from bottom to top. The smooth grouting unit removes burrs from the hole wall, provides cement grout to cover the hole wall, and smooths it. The grouting unit includes a capsule shaped like a convex lens, which is filled with cement grout. A grouting needle extending horizontally is provided at the center of the capsule. The hydraulic bladder plug has a grouting pipe extending along the drilling depth direction in its middle part, and the hydraulic bladder plug is sleeved on the outer wall of the grouting pipe; the scraper assembly includes a fixing plate sleeved on the outer wall of the grouting pipe, and limiting plates concentric with the fixing plate are provided at the top and bottom of the fixing plate. The outer diameter of the limiting plate is larger than the outer diameter of the fixing plate, and both the outer diameter of the limiting plate and the outer diameter of the fixing plate are smaller than the drilling diameter; an annular scraper is sleeved on the outer surface of the fixing plate, and the annular scraper is slidably connected to the fixing plate in the vertical direction. The annular scraper is frustum-shaped and gradually expands outward from bottom to top. The outer diameter of the top surface of the annular scraper is consistent with the drilling diameter, and an elastic reset member is provided between the annular scraper and the limiting plate located at the top of the fixing plate; The grouting assembly includes a grouting ring and a grout storage ring sleeved on the outer wall of the grouting pipe. The grout storage ring is located above the grouting ring and is connected to the grouting ring. The grouting ring is hollow and its outer diameter is the same as the borehole diameter. Multiple grout outlet holes are opened circumferentially at the bottom of the outer wall of the grouting ring. A connecting ring concentric with the grouting ring is provided inside the grouting ring. Multiple sealing rods are distributed circumferentially on the outer surface of the connecting ring. A sealing plate is provided at the end of the sealing rod away from the connecting ring. The sealing plate enables the opening and closing of the grout outlet holes. Multiple connecting rods are provided between the connecting ring and the annular scraper. The smoothing assembly includes a smoothing ring and a recovery ring fitted onto the outer wall of the grouting pipe. The outer diameter of the smoothing ring is the same as the diameter of the drill hole. The recovery ring is located below the smoothing ring. The recovery ring is frustum-shaped and hollow inside. The top diameter of the recovery ring is the same as the diameter of the drill hole, and the top surface of the recovery ring is in contact with the bottom surface of the smoothing ring. Multiple recovery holes are provided circumferentially on the outer wall of the recovery ring. The recovery ring is connected to the grout storage ring.

2. The deep grouting sealing device for existing building pile foundations in water-bearing karst sites according to claim 1, characterized in that, The free end of the grouting needle passes through a through hole on the surface of the capsule and protrudes. A sealing ring made of highly elastic material is provided at the through hole. The outer side of the sealing ring is fixedly connected to the wall of the through hole, and the inner side of the sealing ring is pressed against the wall of the grouting needle. The grouting needle and the capsule are connected and sealed through the sealing ring.

3. The deep grouting sealing device for existing building pile foundations in water-bearing karst sites according to claim 2, characterized in that, The inner surface of the sealing ring and the outer wall of the grouting needle are both smooth surfaces. The sealing ring and the grouting needle can slide relative to each other under the action of external force, but this does not affect the sealing effect of the two.

4. A deep grouting sealing device for existing building pile foundations in water-bearing karst sites according to claim 2, characterized in that, The free end of the grouting needle tube is provided with a cone head, which seals the free end of the grouting needle tube. The tube body of the grouting needle tube is covered with multiple flow holes. When the capsule is in the initial state, all the flow holes are located inside the capsule.

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