A zonal grouting sealing device and construction method for karst caves

Abstract

This invention relates to the field of grouting construction technology for karst caves, specifically a karst cave sealing device and method for zoned grouting. The invention features a positioning support component with a bottom-pointed, top-spreading structure, positioned between the grout guide pipe and the karst cave floor. This achieves fixed-point support at the lower end and suspended grout guidance at the upper end. Throughout the installation and positioning process, no manual maintenance of the grout guide pipe is required, reducing the number of steps in the sealing operation and improving sealing efficiency. The grout guide pipe and positioning support component are strictly coaxially arranged, ensuring that the grout guide pipe remains centered throughout the lowering, positioning, and grouting process, without deviation or jamming. This results in more even stress distribution on the positioning support component. During the initial cement grout delivery into the grout guide pipe, the weight of the cement grout and the internal pressure of the pipe separate the positioning support component from the grout guide pipe, completely freeing up space at the lower end of the grout guide pipe. This prevents the positioning support component from affecting the grout discharge rate at the lower end of the grout guide pipe, ensuring normal grout diffusion and sealing quality.

Description

Technical Field

[0001] This invention relates to the field of grouting construction technology for karst caves, specifically a karst cave sealing device and construction method for zoned grouting. Background Technology

[0002] Karst caves are characterized by their concealed distribution, irregular spatial shapes, and variable filling materials, posing a common geological hazard in geotechnical engineering construction. It is essential to seal karst caves in areas adjacent to subway lines (e.g., within 150m of the subway) to improve the stability of the subway foundation. Common cave heights (vertical clearance from top to bottom) range from within 2m, 2-5m, to over 5m.

[0003] The current standard construction process for sealing and grouting karst caves near subway stations is as follows: First, soil samples are collected through preliminary geological surveys to accurately determine the core parameters such as the location, depth, vertical height, and geological type of the karst caves. Based on this, a special sealing construction plan is formulated. Then, according to the hole position, depth, and diameter parameters specified in the plan, a geological drilling rig is used to complete the drilling operation. Subsequently, grout pipes are laid out and fixed, and finally, grouting and sealing construction is carried out.

[0004] Current construction techniques require high precision in the placement of grouting pipes. Construction specifications stipulate that the top of the grouting pipe must extend approximately 0.5m above the ground, and the bottom must be precisely suspended 0.3–0.5m above the cave floor. Due to the considerable drilling depth of the cave (typically reaching approximately 5m), the grouting pipe must be manually or mechanically held and held in mid-air throughout the lowering process until the top of the pipe is securely fixed to the ground structure via concrete pouring and a flanged sealing sleeve at the borehole opening. Only then can the holding equipment and personnel be removed. This operation requires multiple people and equipment working together to lower, align, and fix the grouting pipe. The insertion process is cumbersome, difficult, and involves high costs in terms of manpower and equipment, significantly reducing the overall efficiency of cave sealing.

[0005] Meanwhile, the distance between the bottom of the grout pipe and the floor of the karst cave is a key parameter for ensuring the quality of the sealing. Exceeding the standard distance will directly affect the density and reinforcement effect of the karst cave sealing. To meet the requirements of precise alignment, ultra-high precision geological surveys must be carried out before construction. Drilling and pipe insertion also require strict control of errors, placing extremely high demands on the accuracy of the preliminary survey and the precision of on-site construction operations. In actual construction, deviations in underground geological parameters and drilling errors can easily cause the installation position of the bottom of the grout pipe to exceed the preset error range. This necessitates secondary surveys and adjustments to the installation position of the grout pipe, further increasing the construction procedures and severely restricting the construction progress and work efficiency of karst cave sealing in karst areas. Summary of the Invention

[0006] The purpose of this invention is to provide a karst cave sealing device and construction method with zoned grouting, so as to solve the problems raised in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a karst cave sealing device for zoned grouting, comprising a grout guide pipe for conveying grout downwards; the device further comprises: A positioning support assembly is disposed at the bottom end of the grout guide pipe; the positioning support assembly includes: A radially shaped supporting bone is connected at its upper end to the bottom end of the grout guide pipe, and several gaps a are formed thereon; the grout flowing out of the bottom opening of the grout guide pipe flows into the cave through the gaps a which are in the open state. A pointed positioning element is disposed at the bottom end of the radial support bone and extends vertically downward for insertion into the bottom plate of the cave, so that the positioning support assembly is supported between the grout guide pipe and the bottom plate of the cave.

[0008] Furthermore, the grout guide pipe and the positioning support assembly are coaxially arranged.

[0009] Furthermore, the radial support bone includes a plurality of skeleton pieces distributed along the circumferential direction of the tip positioning member. The bottom end of the skeleton piece is rotatably connected to the tip positioning member, and the edges of two adjacent skeleton pieces overlap each other, so that the radial support bone can open or close in a lotus shape. The upper end of the skeleton piece is slidably connected to or separated from the slurry guide tube. The gap a is the gap between two adjacent skeleton pieces, which opens or closes synchronously with the radial support bones.

[0010] Furthermore, each of the skeleton pieces is provided with a limiting block at its top, and the bottom of the grout guide tube is provided with a limiting groove that opens downwards. The limiting groove corresponds one-to-one with the limiting block. When the radial support skeleton opens or closes, the limiting groove and the limiting block are inserted into or separated. The limiting block is T-shaped or I-shaped and is adapted to the limiting groove; the limiting groove penetrates the side wall of the slurry guide pipe.

[0011] Furthermore, the tip positioning member has an outer cylinder coaxially mounted on its top, and an inner cylinder is slidably inserted into the outer cylinder. The inner cylinder slides up and down along the axial direction of the outer cylinder. A bowl-shaped tray is fixedly installed on the top of the inner cylinder, with the opening of the tray facing the slurry guide pipe to receive the slurry falling from the slurry guide pipe. A spring is sleeved on the outer side of the outer cylinder, with the lower end of the spring abutting against the bottom of the outer cylinder and the upper end abutting against the lower surface of the tray. The spring always applies an upward elastic force to the tray. When the radial support member is in a fully closed state and the tray is lifted by the spring to its highest point of travel, the outer edge of the top of the tray is tightly fitted with the inner wall of the radial support member.

[0012] Furthermore, the tip positioning component includes a positioning cone and a connecting part at its tip. The connecting part is provided with a plurality of main connecting seats along the circumferential direction. The inner side of the bottom of the skeleton piece is provided with a secondary connecting seat. A rotating shaft is rotatably provided on the main connecting seat. The secondary connecting seat is rotatably connected to the main connecting seat. The top of the connecting part is concentrically provided with an inner diameter limiting plate; when the radial support bone is fully closed, it fits against the outer wall of the inner diameter limiting plate.

[0013] Furthermore, the upper surface of the skeleton piece is arc-shaped, and the lower surface of the grout guide tube is arc-shaped; when the radial support bone is in a fully closed state, the limiting block matches the corresponding limiting groove, and the upper surface of the skeleton piece is in contact with the lower surface of the grout guide tube.

[0014] A method for sealing karst caves using zoned grouting, the method comprising: Step S1: Obtain soil data through on-site survey, input the soil data into the analysis model, and output the sealing plan after running. Drill holes at the construction site according to the hole location, hole depth and hole diameter in the sealing plan. Step S2: After drilling is completed, insert the grout guide pipe with the positioning support component installed at the bottom into the corresponding hole, lower it to the preset elevation, and fix the top of the grout guide pipe to the ground. Step S3: Insert the grouting head into the grouting pipe, fix it, and seal it; Step S4: Prepare grout, and use a power pump to deliver the grout to the grouting head to start the grouting operation until the grouting is completed.

[0015] Furthermore, the slurry concentration delivered to one of the slurry pipes ranges from dilute to viscous.

[0016] Furthermore, both the grout guide pipe and the positioning support assembly are made of PVC material.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention features a positioning support component with a bottom-pointed, top-spreading structure, positioned between the grout guide pipe and the cave floor. This achieves fixed-point support at the bottom and suspended grout guidance at the top. Throughout the installation and positioning process, no manual maintenance of the grout guide pipe is required, reducing the number of steps in the sealing operation and improving sealing efficiency. The grout guide pipe and positioning support component are strictly coaxially arranged, ensuring that the pipe remains centered throughout the lowering, positioning, and grouting process, without deviation or jamming. This results in more even force distribution on the positioning support component. During the initial cement grout delivery, the weight of the cement grout and the internal pressure of the pipe separate the positioning support component from the grout guide pipe, completely freeing up space at the bottom of the grout guide pipe. This prevents the positioning support component from affecting the grout discharge rate at the bottom of the grout guide pipe, ensuring normal grout diffusion and sealing quality. Attached Figure Description

[0018] Figure 1This is a front view of an embodiment of the present invention; Figure 2 This is a front view of another embodiment of the present invention; Figure 3 This is a cross-sectional view of the positioning support component in this invention; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 This is a schematic diagram of the positioning support component when it is fully closed in this invention; Figure 6 This is a partial structural diagram of the present invention; Figure 7 This is a schematic diagram of the positioning support component in this invention when it is opened to its maximum angle; Figure 8 This is a front view of the inner and outer cylinders when they are sleeved together in this invention; Figure 9 This is a schematic diagram of the limiting block in this invention.

[0019] In the diagram: 1. Grout guide pipe; 2. Positioning support assembly; 3. Radial support frame; 4. Tip positioning component; 5. Limiting groove; 6. Outer cylinder; 7. Inner cylinder; 8. Tray; 9. Spring; 10. Main connecting seat; 11. Secondary connecting seat; 12. Rotating shaft; 13. Inner diameter limiting plate; 30. Skeleton piece; 31. Limiting block; 40. Positioning cone; 41. Connecting part. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] See Figures 1-9 The present invention provides a technical solution: a karst cave sealing device for zoned grouting, comprising a grout guide pipe 1, wherein the grout guide pipe 1 is used to convey grout downward; characterized in that the device further comprises: A positioning support assembly 2 is disposed at the bottom end of the grout guide pipe 1; the positioning support assembly 2 includes: The radially shaped support bone 3 is connected at its upper end to the bottom end of the grout pipe 1, and has several gaps a formed thereon; the grout flowing out of the bottom opening of the grout pipe 1 flows into the cave through the gaps a which are in the open state. The tip positioning element 4 is located at the bottom end of the radial support bone 3 and extends vertically downward to be inserted into the bottom plate of the cave, so that the positioning support assembly 2 is supported between the grout pipe 1 and the bottom plate of the cave.

[0022] In one embodiment, reference Figure 1 The positioning support component 2 has an overall structure that is pointed at the bottom and spreads out at the top. It is supported between the grout guide pipe 1 and the bottom plate of the karst cave, realizing fixed support at the lower end and suspended grout guidance at the upper end. During the entire installation and positioning process, there is no need for manual continuous maintenance of the grout guide pipe 1. In this embodiment, the radial support bones 3 are always closed. The positioning support component 2 is provided with several gaps a that are always open for the grout to flow into the karst cave. However, the radial support bones 3 cannot be separated from the grout guide pipe 1. A portion of the grout will be intercepted at the location of the grout guide pipe 1, which will reduce the rate of grout flow and diffusion, resulting in an increasingly higher grout separation rate and affecting the pouring quality.

[0023] In one embodiment, the grout guide pipe 1 and the positioning support assembly 2 are coaxially arranged.

[0024] With this design, the grout guide pipe 1 and the positioning support component 2 are arranged strictly coaxially, ensuring that the grouting, positioning and grouting are centered throughout the process, without deviation or jamming, and the positioning support component 2 is subjected to more uniform force.

[0025] In one embodiment, Figure 2 The radial support bone 3 includes a plurality of skeleton pieces 30 distributed along the circumferential direction of the tip positioning member 4. The bottom end of the skeleton piece 30 is rotatably connected to the tip positioning member 4. The edges of two adjacent skeleton pieces 30 overlap, so that the radial support bone 3 can open or close in a lotus shape. The upper end of the skeleton piece 30 is connected or separated from the slurry pipe 1 by sliding. Figure 1 and Figure 7 The gap a is the gap between two adjacent skeleton pieces 30, which opens or closes synchronously with the radial support bone 3.

[0026] With this design, the slurry flowing from the slurry guide pipe 1 falls into the radial support member 3. After the radial support member 3 is filled, the pressure pump continues to deliver slurry into the slurry guide pipe 1. The pressure inside the radial support member 3 gradually increases. Finally, under the application of external force, the skeleton plate 30 rotates and opens outward. Because the edges of two adjacent skeleton plates 30 overlap, the opening of one skeleton plate 30 will sequentially drive all the remaining skeleton plates 30 to rotate and open outward. During the outward rotation, the upper end of the skeleton plate 30 separates from the slurry guide pipe 1. During the opening process, the gap a between two adjacent skeleton plates 30 gradually increases, and the slurry flows out from the gap a. Figure 7After the skeleton plate 30 is fully opened, the entire positioning support component 2 separates from the grout pipe 1. The grout pipe 1 tilts to one side or does not tilt, and is eventually buried in the concrete and left in the karst cave for single use. When the cement grout is first delivered into the grout pipe 1, the gravity of the cement grout and the pressure inside the pipe are used to separate the positioning support component 2 from the grout pipe 1, so as to avoid the positioning support component 2 affecting the grout discharge rate at the lower end of the grout pipe 1, and to ensure the normal diffusion of the grout and the sealing quality.

[0027] In one embodiment, Figure 6 and Figure 9 Each of the skeleton pieces 30 has a limiting block 31 at its top end, and the bottom of the slurry guide pipe 1 has a limiting groove 5 with an opening facing downward. The limiting groove 5 corresponds one-to-one with the limiting block 31. When the radial support bone 3 opens or closes, the limiting groove 5 is inserted into or separated from the limiting block 31. The limiting block 31 is T-shaped or I-shaped, and the limiting block 31 is adapted to the limiting groove 5; the limiting groove 5 penetrates the side wall of the slurry pipe 1.

[0028] With this design, the limiting groove 5 and the limiting block 31 are tightly connected. The so-called tight connection means that external force is required to make the limiting block 31 slide in the limiting groove 5.

[0029] In one embodiment, the tip positioning member 4 is coaxially provided with an outer cylinder 6, and an inner cylinder 7 is slidably inserted into the outer cylinder 6. The inner cylinder 7 slides up and down along the axial direction of the outer cylinder 6. A bowl-shaped tray 8 is fixedly installed at the top of the inner cylinder 7. The opening of the tray 8 faces the slurry guide pipe 1 and is used to receive the slurry falling from the slurry guide pipe 1. A spring 9 is sleeved on the outer side of the outer cylinder 6. The lower end of the spring 9 abuts against the bottom of the outer cylinder 6, and the upper end abuts against the lower surface of the tray 8. The spring 9 always applies an upward elastic force to the tray 8. When the radial support member 3 is in a fully closed state and the tray 8 is lifted by the spring 9 to its highest point of travel, the top outer edge of the tray 8 is tightly fitted with the inner wall of the radial support member 3.

[0030] With this design, when the radial support bone 3 is closed: the spring 9 pushes the tray 8 to the highest point, and the outer edge of the tray 8 fits against the inner wall of all the skeleton pieces 30, forming a closed grout-receiving cavity, where the grout is temporarily stored and does not leak out; therefore, the outer edge of the tray 8 is not a complete circle, but an irregular shape that fits the inner wall of the skeleton piece 30. After grouting, when the radial support members 3 open: the weight of the grout presses down on the tray 8, causing the inner cylinder 7 to slide down. As the tray 8 moves downward, it pushes the skeleton pieces 30 outward. The grout flows out evenly from the gap a, so that all the skeleton pieces 30 open outward at the same time. There will be no situation where one or more skeleton pieces 30 are closed in place and fail to open successfully, thus avoiding the failure of the radial support members 3 to open and affecting the normal operation of the sealing operation.

[0031] In one embodiment, the tip positioning member 4 includes a positioning cone 40 and a connecting portion 41 at its tip. The connecting portion 41 is provided with a plurality of main connecting seats 10 along the circumferential direction. The inner side of the bottom of the skeleton piece 30 is provided with a secondary connecting seat 11. A rotating shaft 12 is rotatably provided on the main connecting seat 10. The secondary connecting seat 11 is rotatably connected to the main connecting seat 10. The top of the connecting part 41 is concentrically provided with an inner diameter limiting plate 13; when the radial support bone 3 is completely closed, it fits against the outer wall of the inner diameter limiting plate 13.

[0032] With this design, the connection between the positioning support component 2 and the grout guide pipe 1 must be properly made on the ground, aligning the positioning support component 2 with the bottom end of the grout guide pipe 1; the skeleton piece 30 is rotated inward one by one in sequence to close it. During the closing process, the limiting block 31 is inserted into the limiting groove 5 one by one. Because of the obstruction of the inner diameter limiting plate 13, the skeleton piece 30 cannot continue to rotate after encountering the inner diameter limiting plate 13. During the process of the grout guide pipe 1 and the positioning support component 2 in the hole, the inner side of the skeleton piece 30 is obstructed by the inner diameter limiting plate 13, and the outer side is obstructed by the hole wall, ensuring that the skeleton piece 30 will not deform or detach during the process of descending.

[0033] In one embodiment, the upper surface of the skeleton piece 30 is arc-shaped, and the lower surface of the slurry guide tube 1 is arc-shaped; when the radial support bone 3 is in a fully closed state, the limiting block 31 fits into the corresponding limiting groove 5, and the upper surface of the skeleton piece 30 is in contact with the lower surface of the slurry guide tube 1.

[0034] A method for sealing karst caves using zoned grouting, the method comprising: Step S1: Obtain soil data through on-site survey, input the soil data into the analysis model, and output the sealing plan after running. Drill holes at the construction site according to the hole location, hole depth and hole diameter in the sealing plan. Step S2: After drilling is completed, insert the grout guide pipe 1, with the positioning support component 2 installed at the bottom, into the corresponding hole and lower it to the preset elevation. Fix the top of the grout guide pipe 1 to the ground. The positioning support component 2 directly abuts against the bottom plate of the karst cave, ensuring that the lower end of the grout guide pipe 1 is 0.4m above the bottom plate of the karst cave. The upper end of the grout guide pipe 1 is about 0.5m above the ground surface. If it is too high, it can be cut on site. At this time, under the support of the positioning support component 2, the grout guide pipe 1 is naturally suspended in the air without the need for manual or equipment clamping. Then, pour cement grout within 1 meter below the hole opening to fill the gap between the grout guide pipe 1 and the hole wall. After solidification, fix the grout guide pipe 1 to prevent it from shifting during the pumping of cement grout. Step S3: Insert the grouting head into the grouting pipe 1, fix and seal it; so that the grouting pipe 1 is connected to the pressure pump delivery pipe; Step S4: Prepare the grout. Use a power pump to deliver the grout to the grouting head to begin grouting operations until completion. Before grouting each karst cave, set up 3-5 settlement observation points on the ground to achieve millimeter-level monitoring accuracy. Closely monitor changes in the ground surface during grouting to prevent cracks and uplift. If cracks or uplift are detected, immediately reduce the pump pressure and flow rate. Maintain accurate grouting records, including grouting pressure, flow rate, and cement usage. Complete the "Grouting Record Form" and submit it for inspection promptly. Three days after grouting completion, inspect the grouting areas. Re-grout areas that fail to meet standards until all are satisfactory. This achieves the goal of stabilizing and reinforcing the karst cave while maintaining a dynamic balance of zero-disturbance protection for the subway structure.

[0035] The curtain wall is filled with C15 plain concrete.

[0036] With this design, soil data such as soil sample data, location, height, and volume of karst caves, etc., will not be listed here one by one.

[0037] In one embodiment, the slurry concentration delivered to one of the slurry conduits 1 ranges from dilute to viscous. This avoids clogging and better promotes slurry diffusion.

[0038] In one embodiment, both the grout guide pipe 1 and the positioning support assembly 2 are made of PVC. This results in lower construction costs, and after grouting is completed, the grout guide pipe 1 can be left in place, and cement grout can be poured directly to fill the gaps.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0040] It should be noted that if the embodiments of the invention involve directional indicators (such as up and down), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0041] Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B. Additionally, if the embodiments of the invention involve descriptions such as "first," "second," etc., these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, "several" refers to two or more.

[0042] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the invention.

Claims

1. A karst cave sealing device for zoned grouting, comprising a grout guide pipe (1) for conveying grout downwards; characterized in that, The device also includes: A positioning support assembly (2) is disposed at the bottom end of the grout guide pipe (1); the positioning support assembly (2) includes: The radial support bone (3) is connected at its upper end to the bottom end of the grout guide pipe (1), and has a plurality of gaps a formed thereon; the grout flowing out of the bottom opening of the grout guide pipe (1) flows into the cave through the gaps a which are in the open state; The tip positioning component (4) is located at the bottom end of the radial support bone component (3) and extends vertically downwards to be inserted into the bottom plate of the cave, so that the positioning support component (2) is supported between the grout pipe (1) and the bottom plate of the cave.

2. The karst cave sealing device with zoned grouting according to claim 1, characterized in that, The grout guide pipe (1) and the positioning support assembly (2) are coaxially arranged.

3. The karst cave sealing device with zoned grouting according to claim 2, characterized in that, The radial support bone (3) includes a plurality of skeleton pieces (30) distributed along the circumferential direction of the tip positioning piece (4). The bottom end of the skeleton piece (30) is rotatably connected to the tip positioning piece (4). The edges of two adjacent skeleton pieces (30) overlap, so that the radial support bone (3) can open or close in a lotus shape. The upper end of the skeleton piece (30) is connected or separated from the slurry tube (1) by sliding. The gap a is the gap between two adjacent skeleton pieces (30), which opens or closes synchronously with the radial support bone (3).

4. A karst cave sealing device with zoned grouting according to claim 2, characterized in that, Each of the skeleton pieces (30) is provided with a limiting block (31) at its top end, and the bottom of the slurry pipe (1) is provided with a limiting groove (5) with an opening facing downward. The limiting groove (5) corresponds one-to-one with the limiting block (31). When the radial support bone (3) is opened or closed, the limiting groove (5) is inserted into or separated from the limiting block (31). The limiting block (31) is T-shaped or I-shaped, and the limiting block (31) is adapted to the limiting groove (5); the limiting groove (5) penetrates the side wall of the slurry pipe (1).

5. A karst cave sealing device with zoned grouting according to claim 4, characterized in that, The tip positioning member (4) is coaxially provided with an outer cylinder (6), and an inner cylinder (7) is slidably inserted into the outer cylinder (6). The inner cylinder (7) slides up and down along the axial direction of the outer cylinder (6). A bowl-shaped tray (8) is fixedly installed at the top of the inner cylinder (7). The opening of the tray (8) faces the slurry pipe (1) and is used to receive the slurry falling from the slurry pipe (1). A spring (9) is sleeved on the outside of the outer cylinder (6). The lower end of the spring (9) abuts against the bottom of the outer cylinder (6), and the upper end abuts against the lower surface of the tray (8). The spring (9) always applies an upward elastic force to the tray (8). When the radial support member (3) is in a fully closed state and the tray (8) is lifted by the spring (9) to its highest point of travel, the outer edge of the top of the tray (8) is tightly fitted with the inner wall of the radial support member (3).

6. A karst cave sealing device with zoned grouting according to claim 5, characterized in that, The tip positioning component (4) includes a positioning cone (40) and a connecting part (41) at its top. The connecting part (41) is provided with a plurality of main connecting seats (10) along the circumferential direction. The skeleton piece (30) is provided with a secondary connecting seat (11) on the inner side of its bottom. The main connecting seat (10) is provided with a rotating shaft (12). The secondary connecting seat (11) is rotatably connected to the main connecting seat (10). The top of the connecting part (41) is concentrically provided with an inner diameter limiting plate (13); when the radial support bone (3) is fully closed, it fits against the outer wall of the inner diameter limiting plate (13).

7. A karst cave sealing device with zoned grouting according to claim 6, characterized in that, The upper surface of the skeleton piece (30) is arc-shaped, and the lower surface of the slurry guide tube (1) is arc-shaped; when the radial support bone (3) is in a fully closed state, the limiting block (31) fits into the corresponding limiting groove (5), and the upper surface of the skeleton piece (30) is in contact with the lower surface of the slurry guide tube (1).

8. A method for sealing karst caves using zoned grouting, employing the apparatus described in claim 4 of any one of claims 1-7, characterized in that, This construction method includes: Step S1: Obtain soil data through on-site survey, input the soil data into the analysis model, and output the sealing plan after running. Drill holes at the construction site according to the hole location, hole depth and hole diameter in the sealing plan. Step S2: After drilling is completed, insert the grout guide pipe (1) with the positioning support component (2) installed at the bottom into the corresponding hole, lower it to the preset elevation, and fix the top of the grout guide pipe (1) to the ground. Step S3: Insert the grouting head into the grouting pipe (1), fix it and seal it; Step S4: Prepare grout, and use a power pump to deliver the grout to the grouting head to start the grouting operation until the grouting is completed.

9. The method for sealing karst caves by zonal grouting according to claim 8, characterized in that, The slurry concentration delivered to one of the slurry pipes (1) ranges from dilute to viscous.

10. A method for sealing karst caves by zonal grouting according to claim 8, characterized in that, Both the grout guide pipe (1) and the positioning support assembly (2) are made of PVC material.

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