A pile foundation reinforcement cage lowering, rectifying and positioning device and construction method

Abstract

The present application relates to the field of reinforcing cage deviation correction, in particular to a pile foundation reinforcing cage lowering deviation correction positioning device and construction method, the present application comprises a base disc, the base disc is circumferentially provided with a plurality of nozzles, the nozzles are each provided with a flow control valve, the bottom of the base disc is provided with a camera, the base disc is provided with a wireless module, the top of the base disc is provided with a gas storage tank, the flow control valves are all in communication with the gas storage tank, the gas storage tank is used for storing high-pressure gas, the top of the base disc is provided with a pulling rope; both sides of the base disc are provided with receiving holes, the receiving holes are provided with telescopic rods, the ends of the telescopic rods away from the base disc are fixedly connected with clamping claws; the bottom of the base disc is provided with a gas delivery pipe, the gas delivery pipe is in communication with the gas storage tank, the end of the gas delivery pipe away from the base disc is communicated with a horseshoe-shaped air bag, the gas delivery pipe is provided with a reversing valve, and the air bag is used for expanding outside the reinforcing cage after gas injection. The technical scheme of the present application does not need to be deployed on the ground, the base disc is embedded in the reinforcing cage, and the thrust generated by the jet is used to correct the deviation of the reinforcing cage.

Description

Technical Field

[0001] This invention relates to the field of steel cage correction technology, and more specifically, to a device and construction method for lowering and correcting the positioning of a pile foundation steel cage. Background Technology

[0002] With the rapid development of the transportation industry, many transportation facilities, such as roads and bridges, are no longer able to meet current operational needs, leading to increasingly common construction projects involving reconstruction, expansion, and upgrading of road surfaces. Bridge construction is frequently included in these projects, and the quality of pile foundation construction, as the foundation structure of a bridge, directly impacts its usability. The construction of pile foundations requires the lowering of the reinforcing cage. Strict requirements govern the center deviation and protective layer of the reinforcing cage during this process; deviation during lowering significantly impacts construction. This is especially true for pile-to-column structures, where deviation during cage lowering can damage the protective layer, potentially causing borehole collapse. If the reinforcing cage is misaligned when lowered, rework of the pile foundation is necessary, reducing construction speed and wasting manpower and resources, resulting in substantial losses.

[0003] In existing technologies, positioning devices erected on the pile foundation pit are often used to correct the deviation of the reinforcing cage. However, in some cases, the pile may be located on a slope or on a narrow platform, making it difficult for the operator to guide the pile foundation pit from one side, and it is also inconvenient to deploy the device from the other side of the pile foundation pit. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a pile foundation reinforcement cage lowering and positioning device and construction method, which does not require deployment on the ground. It corrects the reinforcement cage by embedding a base plate inside the reinforcement cage and using the thrust generated by air jets.

[0005] This invention is achieved through the following technical solution: a pile foundation steel cage lowering and positioning device, including a base plate, a plurality of nozzles arranged around the base plate, each nozzle being equipped with a flow control valve, a camera at the bottom of the base plate, a wireless module inside the base plate, the wireless module being connected to a controller, a gas storage tank at the top of the base plate, the flow control valves being connected to the gas storage tank, the gas storage tank being used to store high-pressure gas, and a pull rope at the top of the base plate;

[0006] The base plate has storage holes on both sides, and telescopic rods are installed in the storage holes. The end of the telescopic rod away from the base plate is fixedly connected to a claw. The bottom of the base plate is equipped with an air supply pipe, which is connected to an air storage tank. The end of the air supply pipe away from the base plate is connected to a horseshoe-shaped air bladder. A reversing valve is installed inside the air supply pipe. The reversing valve is used to control the inflation and deflation of the air bladder. The air bladder is used to expand outside the steel cage after inflation.

[0007] Furthermore, the airbag has a puncture-resistant layer on its outer side.

[0008] Furthermore, several elastic elements are fixedly connected to the outside of the receiving hole, and buffer pads are fixedly connected to the elastic elements.

[0009] Furthermore, the gas storage tank is detachably connected to the base plate, and a protective shell is provided on the outside of the gas storage tank. A mating ring is provided on the bottom of the outer side of the protective shell, and several bolt holes are opened on the mating ring.

[0010] Furthermore, the base plate has a groove at the bottom, and a flip block is rotatably connected inside the groove. The camera is located on the flip block, and the base plate has a drive component at the bottom for driving the flip block to rotate.

[0011] Furthermore, the flipping block is equipped with an illumination lamp.

[0012] Furthermore, the airbag is covered by a sheath, and a liquid layer is provided between the sheath and the airbag. Several release ports are provided on the sheath, and elastic valves are provided inside the release ports. The elastic valves are used to release the liquid in the liquid layer after the airbag is squeezed.

[0013] Furthermore, a colored coating is applied to the outside of the casing.

[0014] Furthermore, an electronic compass is installed inside the base plate.

[0015] A construction method for a pile foundation reinforcement cage lowering and positioning device includes: Step 1: Install the base plate into the steel cage, and use the telescopic rod to extend so that the claws engage with the steel cage, thus fixing the base plate inside the steel cage. Step 2: Place the airbag outside the steel cage and inject some gas into the airbag through the reversing valve to keep the airbag outside the steel cage. Step 3: Lift the steel cage, move it above the pile foundation pit, and gradually lower it into the pile foundation pit. During the lowering process, use a camera to observe and determine whether the steel cage is aligned with the pile foundation pit. Step 4: When the reinforcing cage deviates from the pile foundation pit, the flow control valve is remotely controlled via wireless module to release airflow in the same direction as the deviation, thereby reducing the deviation between the reinforcing cage and the pile foundation pit. Step 5: After the airbag enters the pile foundation pit, gas is injected into the airbag to inflate it until it abuts against the side wall of the pile foundation pit, thereby centering the steel cage in the pile foundation pit.

[0016] The technical solution of the present invention has at least the following beneficial effects: Unlike conventional correction devices, the base plate does not need to be placed on one side of the pile foundation pit. Instead, it is placed inside the reinforcing cage. A telescopic rod extends out to engage the clamps with the vertical bars of the reinforcing cage, thus fixing the base plate inside. Subsequently, the base plate will be hoisted into the pile foundation pit along with the reinforcing cage.

[0017] During the hoisting of the reinforcing cage, since the cage is suspended in the air and not affected by friction, a small thrust is sufficient to cause lateral displacement. Therefore, by storing high-pressure gas in a gas storage tank and controlling the airflow using a flow control valve, thrust can be generated during hoisting to drive the suspended reinforcing cage to move and align it with the pile foundation pit.

[0018] The diameter of the pile foundation pit is typically slightly larger than that of the reinforcing cage. After the suspended reinforcing cage is aligned with the pile foundation pit using airflow thrust, it can be lowered into the pit. Further restraint can then be achieved using airbags. Upon inflation, the airbags abut against the sidewalls of the pile foundation pit and the reinforcing cage on both sides, allowing the distance between the reinforcing cage and the pit sidewalls to be controlled by the thickness of the airbags. Furthermore, the circumferential expansion of the airbags centers the reinforcing cage within the pile foundation pit, completing the lowering and positioning correction of the reinforcing cage.

[0019] The telescopic rod of the subsequent base plate can retract, thus removing the fixed relationship between the base plate and the reinforcing cage. It is only suspended inside the reinforcing cage by a pull rope. At the same time, the horseshoe-shaped airbag structure will not wrap around the reinforcing cage after deflating, but will deflate and retract into the reinforcing cage. By pulling the pull rope, the base plate and the deflated airbag can be removed from the reinforcing cage. Attached Figure Description

[0020] Figure 1 This is an isometric schematic diagram of an embodiment of the pile foundation reinforcement cage lowering and positioning device of the present invention; Figure 2 This is a front view schematic diagram of an embodiment of the pile foundation reinforcement cage lowering and correction positioning device and construction method of the present invention; Figure 3 This is a top view schematic diagram of an embodiment of the pile foundation reinforcement cage lowering and positioning device of the present invention; Figure 4 This is a schematic diagram of the telescopic rod after retraction in a top view of an embodiment of the pile foundation reinforcement cage lowering and correction positioning device of the present invention; Figure 5 This is a schematic diagram of the flipping block in an embodiment of the pile foundation reinforcement cage lowering and positioning device of the present invention; Figure 6 This is a schematic diagram of the rotating block after rotation in an embodiment of the pile foundation reinforcement cage lowering and correction positioning device of the present invention; Figure 7 This is a schematic cross-sectional view of the airbag structure in an embodiment of the pile foundation reinforcement cage lowering and correction positioning device and construction method of the present invention. Figure 8 This is a cross-sectional schematic diagram of the protective shell of an embodiment of the pile foundation reinforcement cage lowering and positioning device of the present invention.

[0021] Reference numerals: 1. Base plate; 2. Nozzle; 3. Camera; 4. Gas tank; 5. Pull rope; 6. Claw; 7. Gas pipe; 8. Airbag; 9. Elastic element; 10. Buffer pad; 11. Protective shell; 12. Pairing ring; 13. Tank; 14. Tilting block; 15. Illumination lamp; 16. Sheath; 17. Liquid layer; 18. Elastic valve; 19. Telescopic rod. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The following detailed description illustrates the specific implementation method: Example 1 As attached Figures 1-8 As shown, a pile foundation reinforcement cage lowering and positioning device includes a base plate 1, a plurality of nozzles 2 arranged around the base plate 1, each nozzle 2 having a flow control valve installed inside, a camera 3 located at the bottom of the base plate 1, a wireless module located inside the base plate 1, the wireless module being either a WiFi module or a Bluetooth module, the wireless module signal being connected to a controller, the controller being a mobile terminal, a gas storage tank 4 located at the top of the base plate 1, the flow control valves being connected to the gas storage tank 4, the gas storage tank 4 being used to store high-pressure gas, and a pull rope 5 attached to the top of the base plate 1.

[0026] The base plate 1 has storage holes on both sides, and a telescopic rod 19 is bolted in the storage holes. The telescopic rod 19 is a cylinder, and a pawl 6 is bolted to the end of the telescopic rod 19 away from the base plate 1.

[0027] The bottom of the base plate 1 is provided with an air supply pipe 7, which is connected to the air storage tank 4. The end of the air supply pipe 7 away from the base plate 1 is connected to a horseshoe-shaped air bladder 8. The outside of the air bladder 8 is provided with an anti-puncture layer. The air supply pipe 7 is provided with a reversing valve, which is used to control the air release and air injection of the air bladder 8. The air bladder 8 is used to expand outside the steel cage after air injection.

[0028] A construction method for a pile foundation reinforcement cage lowering and positioning device includes: Step 1: Install the base plate 1 inside the steel cage. Extend the telescopic rod 19 to engage the claw 6 with the steel cage, thus fixing the base plate 1 inside the steel cage.

[0029] Step 2: Place the airbag 8 outside the steel cage and inject some gas into the airbag 8 through the reversing valve to keep the airbag 8 outside the steel cage.

[0030] Step 3: Lift the steel cage, move it above the pile foundation pit, and gradually lower it into the pile foundation pit. During the lowering process, use camera 3 to observe and determine whether the steel cage is aligned with the pile foundation pit.

[0031] Step four: When the reinforcing cage deviates from the pile foundation pit, the flow control valve is remotely controlled via a wireless module to release airflow in the same direction as the deviation, thereby reducing the deviation between the reinforcing cage and the pile foundation pit.

[0032] Step 5: After the airbag 8 enters the pile foundation pit, gas is injected into the airbag 8 to inflate it until it abuts against the side wall of the pile foundation pit, thereby centered the steel cage in the pile foundation pit.

[0033] Under certain construction conditions, such as when the pile foundation pit is located on a slope or the platform on which the pile foundation pit is located is small, it is difficult to deploy correction or positioning devices on the ground. In this embodiment, a base plate 1 is used as the structural carrier for the positioning operation of the reinforcing cage. By assembling it into the reinforcing cage and enabling it, the reinforcing cage can be corrected and positioned without occupying ground space.

[0034] The base plate 1 is fixed to the reinforcing cage by the claws 6 on the telescopic rod 19 inside the receiving hole. The claws 6 can conform to the shape of the vertical reinforcing bars and thus lock onto the reinforcing cage. At the same time, the telescopic rod 19 continuously drives the claws 6 to move closer to the vertical reinforcing bars of the reinforcing cage, so that the claws 6 are tightly pressed against the vertical reinforcing bars of the reinforcing cage, and the base plate 1 is stably locked in the reinforcing cage.

[0035] The base plate 1 provides driving force by ejecting high-pressure gas through nozzle 2. During the hoisting of the reinforcing cage, since the cage is suspended and not affected by friction, a small thrust is sufficient to cause lateral displacement. Therefore, by storing high-pressure gas in the gas storage tank 4, thrust can be generated during hoisting to drive the suspended reinforcing cage to move and align it with the pile foundation pit. The thrust can be controlled by adjusting the airflow rate using a flow control valve. By controlling the airflow rate based on the deviation distance of the reinforcing cage, the correction force can be adjusted. The user can remotely control the system from the ground via a wireless module to regulate the airflow rate. A camera 3 located at the bottom of the base plate 1 can capture images from the bottom for remote viewing, facilitating analysis of the deviation.

[0036] However, jet propulsion only adjusts the position of the steel cage by generating thrust. Since the instability of steel cage hoisting mainly comes from hoisting sway, and hoisting sway is random and difficult to predict accurately, the thrust can only compensate after swaying occurs, so there is a delay. Therefore, the adjustment capability of jet propulsion is still limited.

[0037] The reinforcing cage will be lowered into the pile foundation pit, where it can be further restrained using airbags 8. After inflating, the airbags 8 will abut against the sidewalls of the pile foundation pit and the reinforcing cage on both sides, allowing the distance between the reinforcing cage and the sidewalls of the pile foundation pit to be controlled by the thickness of the airbags 8. Furthermore, through the circumferential expansion of the airbags 8, the reinforcing cage is centered in the pile foundation pit, completing the lowering and positioning correction of the reinforcing cage.

[0038] Therefore, this embodiment divides the correction process into two parts. One part is to use the nozzle 2 to spray high-pressure gas to adjust the position of the reinforcing cage so that the reinforcing cage can be aligned with the pile foundation pit and smoothly enter the pile foundation pit. After the airbag 8 enters the pile foundation pit, the airbag 8 expands and uses the pile foundation pit wall as support to center the reinforcing cage in the pile foundation pit.

[0039] The telescopic rod 19 of the subsequent base plate 1 can retract, so that the base plate 1 is no longer fixed to the reinforcing cage, but is only suspended inside the reinforcing cage by the pull rope 5. At the same time, the horseshoe-shaped airbag 8 structure will not wrap around the reinforcing cage after deflating, but will deflate and retract into the reinforcing cage. By pulling the pull rope 5, the base plate 1 and the deflated airbag 8 can be removed from the opening at the top of the reinforcing cage, leaving only the reinforcing cage in the pile foundation pit, without affecting the subsequent grouting.

[0040] Since the airbag 8 is small in volume when deflated, a certain amount of gas should be injected into the airbag 8 before hoisting the steel cage to keep the airbag 8 on the outside of the steel cage. After the airbag 8 enters the pile foundation pit, it should be further inflated to expand it, so as to prevent the airbag 8 from failing to expand properly outside the steel cage after entering the pile foundation pit.

[0041] Example 2 The difference from the above embodiment is that several elastic elements 9 are welded and fixed to the outside of the receiving hole, and a buffer pad 10 is bonded and fixed to the elastic elements 9. The bottom of the base plate 1 is provided with a groove 13, and a flip block 14 is rotatably connected in the groove 13. The camera 3 is located on the flip block 14, and an illumination lamp 15 is provided on the flip block 14. The bottom of the base plate 1 is provided with a driving component for driving the flip block 14 to rotate, and the driving component is a motor.

[0042] The reinforcing cage will sway during hoisting. After the reinforcing cage reaches the designated position, the base plate 1 will also sway as it is pulled out by the tug rope 5, potentially causing a collision with the reinforcing cage. The telescopic rod 19 and the claws 6, located on the outer side of the base plate 1, are more susceptible to impact. Therefore, a buffer pad 10 connected by an elastic element 9 is installed. The claws 6 can extend the telescopic rod 19 to push open the buffer pad 10, allowing it to contact the reinforcing cage. After the telescopic rod 19 retracts, the buffer pad 10 can also return to its original position via the elastic element 9, thus protecting the claws 6 and the telescopic rod 19 from collision.

[0043] The camera 3 at the bottom of the base plate 1 is relatively expensive, and its repair cost would be high if damaged by a collision. Therefore, a flipping block 14 is installed at the bottom of the base plate 1. During the non-use period of the camera 3, the flipping block 14 will flip the camera 3 upwards, so that even if the bottom of the base plate 1 is hit, the flipping block 14 can effectively protect the camera 3. At the same time, since the light inside the pile foundation pit is limited, an illumination lamp 15 is installed next to the camera 3 so that there is sufficient light for observation after the airbag 8 is inserted into the pile foundation pit.

[0044] Example 3 The difference from the above embodiment is that the gas storage tank 4 is detachably connected to the base plate 1, the gas storage tank 4 is provided with a protective shell 11, the bottom of the outer side of the protective shell 11 is provided with a mating ring 12, and the mating ring 12 is provided with several bolt holes.

[0045] After the reinforcement cage is lowered, the base plate 1 will be lifted out through the openings at both ends of the reinforcement cage due to the narrowness of the pile foundation pit. However, when assembling the base plate 1, it is not necessary to enter through the openings at both ends of the reinforcement cage. It can be directly inserted into the reinforcement cage through the gaps between the reinforcement bars. The detachable connection between the air storage tank 4 and the base plate 1 reduces the overall volume and makes it easier for users to insert the air storage tank 4 and the base plate 1 into the reinforcement cage through the gaps between the reinforcement bars and then assemble them.

[0046] Example 4 The difference from the above embodiment is that the airbag 8 is provided with a sleeve 16, and a liquid layer 17 is provided between the sleeve 16 and the airbag 8. The liquid layer 17 is clean water. The sleeve 16 has several release ports, and an elastic valve 18 is provided in the release ports. The elastic valve 18 is used to release the liquid in the liquid layer 17 after the airbag 8 is squeezed. The sleeve 16 is provided with a colored coating.

[0047] The liquid layer 17 between the sleeve 16 and the airbag 8 acts as a lubricant. When the airbag 8 inflates to a certain volume or comes into contact with the pile foundation pit wall, the liquid layer 17 is subjected to significant compressive pressure, causing it to break through the constraint of the elastic valve 18 and be released onto the surface of the sleeve 16. This lubricates the sleeve 16 against the pile foundation pit wall, facilitating the sliding of the airbag 8 against the pit wall and aiding in the centering and insertion of the reinforcing cage. Furthermore, the sleeve 16 has a colored coating that is more conspicuous than the silver-gray of the reinforcing steel, making it easier to judge the edges. When the user observes through the camera 3, they can determine the edge of the airbag 8 by the position of the sleeve 16, and then correct any deviations to align the reinforcing cage with the pile foundation pit.

[0048] Example 5 The difference from the above embodiment is that the base plate 1 is equipped with an electronic compass.

[0049] Since the airflow needs to be ejected from the nozzles 2 remotely based on the offset direction, the orientation of each nozzle 2 needs to be known. The electronic compass can measure the orientation of the base plate 1, thus allowing the user to obtain the orientation of each nozzle 2 for adjustment of the offset.

[0050] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A device for positioning and correcting deviations when lowering a pile foundation reinforcement cage, characterized in that, Includes a base plate (1), which has several nozzles (2) arranged around its perimeter. Each nozzle (2) is equipped with a flow control valve. A camera (3) is installed at the bottom of the base plate (1). A wireless module is installed inside the base plate (1). The wireless module is connected to a controller. A gas storage tank (4) is installed at the top of the base plate (1). The flow control valves are all connected to the gas storage tank (4). The gas storage tank (4) is used to store high-pressure gas. A pull rope (5) is installed at the top of the base plate (1). The base plate (1) has storage holes on both sides, and a telescopic rod (19) is provided in the storage holes. A claw (6) is fixedly connected to the end of the telescopic rod (19) away from the base plate (1). The bottom of the base plate (1) is provided with an air supply pipe (7), which is connected to the air storage tank (4). The end of the air supply pipe (7) away from the base plate (1) is connected to a horseshoe-shaped air bladder (8). A reversing valve is provided inside the air supply pipe (7). The reversing valve is used to control the air release and air injection of the air bladder (8). The air bladder (8) is used to expand outside the steel cage after air injection.

2. The pile foundation reinforcement cage lowering and positioning device according to claim 1, characterized in that, The airbag (8) has a puncture-proof layer on the outside.

3. The pile foundation reinforcement cage lowering and positioning device according to claim 1, characterized in that, Several elastic elements (9) are fixedly connected to the outside of the receiving hole, and a buffer pad (10) is fixedly connected to the elastic elements (9).

4. The pile foundation reinforcement cage lowering and positioning device according to claim 1, characterized in that, The gas storage tank (4) is detachably connected to the base plate (1). The gas storage tank (4) is provided with a protective shell (11). A matching ring (12) is provided at the bottom of the outer side of the protective shell (11). Several bolt holes are provided on the matching ring (12).

5. The pile foundation reinforcement cage lowering and positioning device according to claim 1, characterized in that, The base plate (1) has a groove (13) at the bottom, and a flip block (14) is rotatably connected inside the groove (13). The camera (3) is located on the flip block (14). The base plate (1) has a drive component at the bottom for driving the flip block (14) to rotate.

6. The pile foundation reinforcement cage lowering and positioning device according to claim 5, characterized in that, An illumination lamp (15) is provided on the flip block (14).

7. The pile foundation reinforcement cage lowering and positioning device according to claim 1, characterized in that, The airbag (8) is provided with a sleeve (16) on the outside, and a liquid layer (17) is provided between the sleeve (16) and the airbag (8). Several release ports are provided on the sleeve (16), and an elastic valve (18) is provided in the release port. The elastic valve (18) is used to release the liquid in the liquid layer (17) after the airbag (8) is squeezed.

8. The pile foundation reinforcement cage lowering and positioning device according to claim 7, characterized in that, The outer layer (16) is coated with a color coating.

9. The pile foundation reinforcement cage lowering and positioning device according to claim 1, characterized in that, An electronic compass is installed inside the base plate (1).

10. The construction method of the pile foundation reinforcement cage lowering and positioning device according to claim 1, characterized in that, include: Step 1: Install the base plate (1) into the steel cage. Extend the telescopic rod (19) to make the claw (6) engage with the steel cage and fix the base plate (1) inside the steel cage. Step 2: Place the airbag (8) outside the steel cage and inject some gas into the airbag (8) through the reversing valve to keep the airbag (8) outside the steel cage; Step 3: Lift the steel cage, move it above the pile foundation pit and gradually lower it into the pile foundation pit. During the lowering process, use camera (3) to observe and determine whether the steel cage is aligned with the pile foundation pit. Step 4: When the reinforcing cage deviates from the pile foundation pit, the flow control valve is remotely controlled via wireless module to release airflow in the same direction as the deviation, thereby reducing the deviation between the reinforcing cage and the pile foundation pit. Step 5: After the airbag (8) enters the pile foundation pit, gas is injected into the airbag (8) to inflate it until it abuts against the side wall of the pile foundation pit, thereby centered the steel cage in the pile foundation pit.

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