A method for removing a pile head of a large-diameter pile by floating slurry super-filling based on a split structure

Abstract

The application discloses a method for removing a pile head of a large-diameter pile by floating slurry and over-piling based on a separated structure, and comprises a pile head steel casing and a reserved pile foundation steel casing.The pile foundation steel casing adopts a separated structure of a pile head and a main body, so that the pile head steel casing and pile head concrete can be directly lifted away from the pile head when the pile head is removed, and cutting of the steel casing and stripping of the concrete and the like are omitted.The elastic wrapping material and sleeve pipe on the main reinforcement and sounding pipe of the pile head can effectively cut off the grip of the concrete on the main reinforcement and sounding pipe of the pile head, the pile head steel casing and the pile head concrete can be directly lifted away as a whole after the pile is formed by the method, a large amount of manpower and material resources are saved, the main reinforcement can be effectively protected, and the problem of accidental cutting or damage of the main reinforcement in the process of cutting, removing and stripping of the concrete is avoided.Meanwhile, the pile head steel casing is recyclable, can be repeatedly used at the same pile site with the same pile diameter, and can effectively reduce construction cost and improve construction efficiency.

Description

Technical Field

[0001] This invention relates to a construction method for over-grown pile heads of large-diameter piles, specifically a method for removing over-grown pile heads of large-diameter piles based on a separated structure, belonging to the technical field of over-grown pile head removal for large-diameter cast-in-place piles. Background Technology

[0002] Large-diameter drilled (or driven) cast-in-place piles are widely used in bridge pile foundations in marine areas. During concrete pouring, a certain area at the top of the pile contains laitance, which is generally thick and has low strength, failing to meet design requirements. To ensure the quality and strength of the pile head, concrete is usually poured beyond the design elevation. The excess portion is later removed through processes such as pile head breaking, and the exposed main reinforcement is reused in subsequent construction. Furthermore, soil and other impurities inevitably fall into the pile head during concrete pouring. Therefore, regulations stipulate that the pile head elevation should be 0.5-1.0m higher than the design elevation during concrete pile construction, and this portion of the pile head concrete is removed to ensure the strength of the pile body.

[0003] The traditional method of manually removing pile heads involves manually chiseling out the main reinforcing bars and sonic logging tubes of the steel cage using a pneumatic pick after the foundation excavation is completed, then separating the pile head, and finally using heavy machinery to lift the pile head. This method has many shortcomings:

[0004] (1) Sonic logging tubes are difficult to locate, which is time-consuming and inefficient;

[0005] (2) It is slow to chisel out the main reinforcement and sonic logging tube of the steel cage. If the construction workers are not careful, they will often damage the steel bars, causing them to bend and deform, thereby reducing the tensile strength. This will weaken the connection between the pile foundation and the pile cap, creating a weak point when an earthquake occurs.

[0006] (3) The concrete must reach sufficient strength before cutting to ensure that the pile body will not be damaged when the pneumatic cutting machine is used to break it, which will affect the construction period.

[0007] (4) Using manual methods will cause health problems for construction workers. The huge vibration of the hand-held pneumatic equipment will damage the operator's wrists and arms, and the noise and dust generated will also create a poor working environment. Moreover, the pile head after breaking is uneven, which will cause some damage to the pile foundation. Summary of the Invention

[0008] The purpose of this invention is to provide a method for removing over-grouted pile heads of large-diameter piles based on a split structure. During pile chiseling operations, the steel cylinder retaining and pile head of the over-grouted portion can be quickly removed, while protecting the exposed main reinforcement required for subsequent construction from damage, thereby improving construction efficiency.

[0009] This invention achieves the above objective through the following technical solution: a method for removing over-grouting of large-diameter pile heads based on a split structure, comprising...

[0010] The pile head steel casing constitutes the upper structure of the over-irrigated pile head. The top of the pile head steel casing is symmetrically equipped with lifting rings, and the outer side is equipped with a slider control rocker arm for controlling the slider placed in the slider rail. The bottom of the pile head steel casing is set as a pile head steel casing bottom ring. The pile head steel casing bottom ring has an integrated main reinforcement / sonic logging pipe sleeve vertically connected to it. The bottom interlayer of the pile head steel casing bottom ring is equipped with a fan-shaped slider.

[0011] The retained pile foundation steel casing forms the lower end structure of the over-grown pile head and is seamlessly connected to the pile head steel casing. The inner side wall of the retained pile foundation steel casing is vertically connected with the main reinforcement of the steel cage and the sonic logging tube. The lowest point of the elastic material layer is slightly lower than the pile top elevation line after the pile head is removed.

[0012] As a further embodiment of the present invention: the bottom of the pile head steel casing is integrally enlarged-diameter conical.

[0013] As a further aspect of the present invention: the portions of the main reinforcing bars of the steel cage and the sonic logging pipe located in the over-irrigation area need to be wrapped with an elastic material layer.

[0014] As a further aspect of the present invention: after the pile head steel casing is connected to the retained pile foundation steel casing and the main reinforcement of the steel cage, the top elevation of the main reinforcement / sonic logging pipe casing should be higher than the sum of the design elevation of the pile top and the height of the over-grown portion.

[0015] As a further aspect of the present invention, the inner wall of the pile head steel casing, the outer side of the casing, the upper and lower surfaces of the bottom ring, and the surface of the fan-shaped slider in the bottom interlayer of the pile head steel casing are coated with concrete release agent before construction.

[0016] A method for removing over-grouted slurry from large-diameter pile heads based on a split structure includes the following steps:

[0017] Step 1: During the construction of bored piles, the part of the steel casing at the pile head above the pile top elevation is set as a separate structure. The bottom of the steel casing in the pile head area is an enlarged cone shape, and the minimum inner diameter is the same as that of the steel casing of the retained pile foundation. The two can be directly connected. The top of the steel casing at the pile head is equipped with a lifting ring, which is used to lift the steel casing at the pile head together with the pile head concrete after the pile is completed.

[0018] Step 2: The bottom of the pile head steel casing is circular to ensure that the guide pipe can be lowered normally during the construction of the cast-in-place pile. The bottom circular ring of the pile head steel casing has a hollow sleeve extending upward at the position of the main reinforcement of the reinforcing cage. The top elevation of the hollow sleeve should be slightly higher than the top elevation of the cast-in-place pile before the over-poured part is removed, and the inner diameter is slightly larger than the diameter of the main reinforcement of the cast-in-place pile reinforcing cage. It is an integral structure with the bottom circular ring. After connecting the pile head steel casing and the retained pile foundation steel casing, these hollow sleeves will protect the main reinforcement inside, preventing the main reinforcement of the pile head from getting tangled with the concrete.

[0019] Step 3: Before lowering the steel cage, wrap the area where the main reinforcement bars and the sonic logging pipe are located at the pile head with an elastic material layer. This ensures that after the pile head steel casing is put on, the casing and the elastic material are in close contact to achieve a sealing effect and prevent the poured concrete from floating up and intruding into the gap between the casing and the main reinforcement bars.

[0020] Step 4: The bottom ring structure of the pile head steel casing has a bottom interlayer. Inside the interlayer are eight fan-shaped sliders with a central angle of 45°. These sliders can form a disk with a diameter larger than the inner diameter of the bottom ring of the pile head steel casing. The eight fan-shaped sliders are fixed on their respective guide rails and can be moved by the rocker arm outside the pile head steel casing. After moving outward and dispersing, the eight fan-shaped sliders can be hidden in the interlayer. When they all move inward, the circle formed by the fan-shaped sliders can completely seal the hollow part of the bottom ring of the pile head steel casing. After a period of time after the grouting construction is completed, when the upper layer of laitance is formed, the pile head laitance can be completely separated from the pile foundation concrete by moving the sliders.

[0021] Step 5: During the construction of cast-in-place concrete piles, after the aggregate has settled for a period of time and the slurry has formed at the pile head, control the slider to close the slider in the interlayer, completely separating the pile head concrete from the pile foundation. After the pile is formed, use the lifting ring on the pile head steel casing to lift the pile head steel casing 1 together with the pile head concrete. Then remove the elastic material layer on the pile head reinforcement to expose the main reinforcement. The removal of the pile head and excess steel casing of the over-poured concrete pile is completed, and subsequent construction can proceed.

[0022] The beneficial effects of this invention are as follows: The steel casing for pile foundations adopts a structure that separates the pile head from the main body, allowing the steel casing and pile head concrete to be directly lifted away during pile head removal, eliminating the need for cutting and peeling the steel casing from the concrete. The elastic wrapping material and sleeve on the main reinforcement and sonic logging pipe at the pile head effectively prevent the concrete from gripping the main reinforcement and sonic logging pipe. After pile formation, the steel casing and pile head concrete treated in this way can be lifted away as a whole, eliminating the need for the traditional pile head removal method, which involves breaking the entire concrete cover of the pile head, pulling out the reinforcement, and finally breaking the core concrete. This saves a significant amount of manpower and resources, shortens the time required for pile head removal, and effectively protects the main reinforcement, avoiding accidental cutting or damage to the main reinforcement during the cutting, removal, and peeling of concrete. Furthermore, the use of a recyclable steel casing allows for reuse at pile locations of the same diameter, effectively reducing construction costs and improving construction efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the split pile foundation casing of the present invention;

[0024] Figure 2 This is a cross-sectional view of the steel casing for the pile head of the present invention;

[0025] Figure 3 This is a schematic diagram of the elastic material wrapping of the reinforcing bar / acoustic logging tube of the present invention;

[0026] Figure 4 This is a schematic diagram illustrating the closing principle of the interlayer slider of the pile head steel casing according to the present invention;

[0027] Figure 5 This is a schematic diagram illustrating the opening principle of the sliding block of the pile head steel casing interlayer in this invention.

[0028] In the diagram: 1. Steel casing for pile head; 2. Retained steel casing for pile foundation; 21. Main reinforcement of steel cage; 22. Sonic logging tube; 23. Elastic material layer; 24. Over-irrigated area; 25. Elevation line of pile top after pile head removal; 3. Lifting ring; 31. Slider; 32. Slider rail; 33. Bottom interlayer of steel casing for pile head; 4. Main reinforcement / sonic logging tube sleeve; 5. Fan-shaped slider; 6. Slider control rocker arm; 7. Bottom ring of steel casing for pile head. Detailed Implementation

[0029] 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.

[0030] Example 1

[0031] Please see Figures 1-5 A method for removing over-grouting of large-diameter pile heads based on a split structure, comprising:

[0032] The pile head steel casing 1 constitutes the upper structure of the over-irrigated pile head. The top of the pile head steel casing 1 is symmetrically provided with lifting rings 3, and the outer side is provided with a slider control rocker arm 6 for controlling the slider 31 placed in the slider rail 32. The bottom of the pile head steel casing 1 is provided with a pile head steel casing bottom ring 7. The pile head steel casing bottom ring 7 is vertically connected with an integrated main reinforcement / sonic logging pipe sleeve 4. The pile head steel casing bottom interlayer 33 of the pile head steel casing bottom ring 7 is provided with a fan-shaped slider 5.

[0033] The retained pile foundation steel casing 2 constitutes the lower end structure of the over-grown pile head and is seamlessly connected to the pile head steel casing 1. The inner side wall of the retained pile foundation steel casing 2 is vertically connected with the main reinforcing bar 21 of the steel cage and the sonic logging tube 22. The lowest point of the elastic material layer 23 is slightly lower than the pile top elevation line 25 after the pile head is removed.

[0034] In this embodiment of the invention, the bottom of the pile head steel casing 1 is an enlarged-diameter cone shape.

[0035] In this embodiment of the invention, the portion of the main reinforcement 21 and the sonic logging pipe 22 located in the over-pouring area 24 needs to be wrapped with an elastic material layer 23. After wrapping, there is no gap between the main reinforcement and the sonic logging pipe and the main reinforcement / sonic logging pipe sleeve 4, so as to avoid the intrusion of floating concrete.

[0036] In this embodiment of the invention, after the pile head steel casing 1 is connected to the retained pile foundation steel casing 2 and the main reinforcement 21 of the reinforcing cage, the top elevation of the main reinforcement / sonic logging tube casing 4 should be higher than the sum of the design elevation 25 of the pile top and the height of the over-poured portion. This can prevent concrete from entering from the top of the casing 4 and causing difficulties for the pile head removal work.

[0037] In this embodiment of the invention, the inner wall of the pile head steel casing 1, the outer side of the casing, the upper and lower surfaces of the bottom ring, and the surface of the fan-shaped slider 5 in the bottom interlayer 33 of the pile head steel casing are coated with concrete release agent before construction, so that the pile head steel casing 1 and the pile head concrete do not stick to the lower pile body concrete when the whole is lifted, reducing the difficulty of construction.

[0038] Example 2

[0039] A method for removing over-grouted slurry from large-diameter pile heads based on a split structure includes the following steps:

[0040] Step 1: During the construction of bored piles, the portion of the steel casing 1 at the pile head above the pile top elevation is set as a separate structure. The bottom of the steel casing in the pile head area is an enlarged cone shape, and the minimum inner diameter is the same as that of the retained pile foundation steel casing 2. The two can be directly connected. The top of the steel casing 1 at the pile head is equipped with a lifting ring 3, which is used to lift the steel casing 1 at the pile head together with the pile head concrete after the pile is completed.

[0041] Step 2: The bottom of the pile head steel casing 1 is circular to ensure that the guide pipe can be lowered normally during the construction of the cast-in-place pile. The bottom circular ring 7 of the pile head steel casing has a hollow sleeve extending upward at the position of the main reinforcement 21 of the reinforcing cage. The top elevation of the hollow sleeve should be slightly higher than the top elevation of the cast-in-place pile before the over-poured part is removed, and the inner diameter is slightly larger than the diameter of the main reinforcement of the cast-in-place pile reinforcing cage. It is an integral structure with the bottom circular ring. After connecting the pile head steel casing 1 and the retained pile foundation steel casing 2, these hollow sleeves will protect the main reinforcement inside to prevent the main reinforcement of the pile head from getting tangled with the concrete.

[0042] Step 3: Before lowering the steel cage, wrap the area of ​​the main steel bar 21 and the sonic logging tube 22 at the pile head with an elastic material layer 23 so that after the pile head steel casing is put on, the casing and the elastic material are in close contact to achieve a sealing effect and prevent the poured concrete from floating and intruding into the gap between the casing and the main steel bar.

[0043] Step 4: The bottom ring 7 of the pile head steel casing has a bottom interlayer 33. Inside the interlayer are eight fan-shaped sliders 5 with a central angle of 45°. These sliders can form a disk with a diameter larger than the inner diameter of the bottom ring 7 of the pile head steel casing. The eight fan-shaped sliders 5 are fixed on their respective guide rails and can be moved by the rocker arm outside the pile head steel casing 1. After moving outward and dispersing, the eight fan-shaped sliders 5 can be hidden in the interlayer. When they all move inward, the circle formed by the fan-shaped sliders 5 can completely seal the hollow part of the bottom ring 7 of the pile head steel casing. After a period of time after the grouting construction is completed, when the upper layer of laitance is formed, the pile head laitance can be completely separated from the pile foundation concrete by moving the slider 31.

[0044] Step 5: During the construction of cast-in-place concrete piles, after the aggregate settles for a period of time and the slurry forms at the pile head, the rocker arm 6 is controlled by the slider to close the slider in the interlayer, completely separating the pile head concrete from the pile foundation. After the pile is formed, the pile head steel casing 1 is lifted off together with the pile head concrete using the lifting ring 3 on the pile head steel casing 1. Then, the elastic material layer 23 on the pile head steel reinforcement is removed to expose the main reinforcement. The removal of the pile head and excess steel casing of the over-poured concrete pile is completed, and subsequent construction can proceed.

[0045] Working Principle: The pile head steel casing 1 is equipped with a lifting ring. The bottom of the casing has a sandwich structure containing a fan-shaped slider that can move along a guide rail. The slider's movement is controlled by a control rocker arm outside the casing. A sleeve is located at the main reinforcement position of the pile head steel casing 1. The main reinforcement and sonic logging tube at the pile head are first wrapped with elastic material. After the steel casing is fitted, there is no gap between the sleeve and the main reinforcement, preventing them from gripping the poured concrete. This facilitates the removal of the pile head concrete and protects the main reinforcement, avoiding accidental cutting or damage to the reinforcement during concrete cutting, chiseling, and stripping. After a period of concrete pouring, laitance forms. At this time, the bottom of the steel casing can be closed by moving the slider with the rocker arm, separating the pile head concrete from the pile body concrete. After pile formation, the steel casing and pile head concrete can be lifted away together using the lifting ring, exposing the main reinforcement, completing the pile head removal work.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for removing over-grouting of large-diameter pile heads based on a split structure, characterized in that: include The pile head steel casing (1) constitutes the upper structure of the over-irrigated pile head. The top of the pile head steel casing (1) is symmetrically provided with lifting rings (3), and the outside is provided with a slider control rocker arm (6) for controlling the slider (31) placed in the slider rail (32). The steel casing (2) of the pile foundation is retained, which constitutes the lower end structure of the over-irrigated pile head and is seamlessly connected with the steel casing (1) of the pile head; The bottom of the pile head steel casing (1) is set as a bottom ring (7) of the pile head steel casing, and an integrated main reinforcement / sonic logging pipe sleeve (4) is vertically connected to the bottom ring (7) of the pile head steel casing. The bottom ring (7) of the pile head steel casing is provided with a fan-shaped slider (5) in the bottom interlayer (33) of the pile head steel casing. The above-mentioned method for removing over-grouting of large-diameter pile heads based on a split structure includes the following steps: Step 1: During the construction of bored piles, the part of the pile head steel casing (1) above the pile top elevation is set as a separate structure. The bottom of the steel casing in the pile head area is an enlarged cone shape, and the minimum inner diameter is consistent with the retained pile foundation steel casing (2). The two can be directly connected. The top of the pile head steel casing (1) is equipped with a lifting ring (3) to lift the pile head steel casing (1) together with the pile head concrete after the pile is completed. Step 2: The bottom of the pile head steel casing (1) is circular to ensure that the guide pipe can be lowered normally during the construction of the cast-in-place pile. The bottom circular ring (7) of the pile head steel casing has an upward-extending hollow sleeve at the position of the main reinforcement (21) of the steel cage. The top elevation of the hollow sleeve should be slightly higher than the top elevation of the cast-in-place pile before the over-poured part is removed. The inner diameter is slightly larger than the diameter of the main reinforcement of the cast-in-place pile steel cage. It is an integral structure with the bottom circular ring. After connecting the pile head steel casing (1) and the retained pile foundation steel casing (2), these hollow sleeves will protect the main reinforcement inside to prevent the main reinforcement of the pile head from getting tangled with the concrete. Step 3: Before lowering the steel cage, wrap the area of ​​the main steel bar (21) and the sonic logging tube (22) at the pile head with an elastic material layer (23) so that after the pile head steel casing (1) is put on, the casing and the elastic material are in close contact to achieve a sealing effect and prevent the poured concrete from floating and invading the gap between the casing and the main steel bar. Step 4: The bottom ring (7) of the pile head steel casing is equipped with a bottom interlayer (33). Inside the interlayer are eight fan-shaped sliders (5) with a central angle of 45°. They can form a disc with a diameter larger than the inner diameter of the bottom ring (7) of the pile head steel casing. The eight fan-shaped sliders (5) are fixed on their respective guide rails and can be moved by the rocker arm outside the pile head steel casing. After moving outward and dispersing, the eight fan-shaped sliders (5) can be hidden in the interlayer. When they all move inward, the circle formed by the fan-shaped sliders (5) can completely seal the hollow part of the bottom ring (7) of the pile head steel casing. After a period of time after the grouting construction is completed, when the upper layer of slurry is formed, the slurry of the pile head can be completely separated from the pile foundation concrete by moving the slider (31). Step 5: During the construction of the concrete cast-in-place pile, after the aggregate settles for a period of time after the grout is poured, the rocker arm (6) is controlled by the slider to close the fan-shaped slider in the interlayer, completely separating the concrete at the pile head from the pile foundation. After the pile is formed, the steel casing (1) at the pile head is lifted off together with the concrete at the pile head through the lifting ring (3) on the steel casing (1). Then, the elastic material layer (23) on the steel reinforcement at the pile head is removed to expose the main reinforcement. The removal of the over-poured concrete pile head and the excess steel casing is completed, and subsequent construction can proceed.

2. The method for removing over-grouting of large-diameter pile heads based on a split structure according to claim 1, characterized in that: The inner wall of the retained pile foundation steel casing (2) is vertically connected with the main reinforcement of the steel cage (21) and the sonic logging tube (22), and the lowest point of the elastic material layer (23) is lower than the pile top elevation line (25) after the pile head is removed.

3. The method for removing over-grouting of large-diameter pile heads based on a split structure according to claim 1, characterized in that: The bottom of the pile head steel casing (1) is an enlarged cone shape.

4. The method for removing over-grouting of large-diameter pile heads based on a split structure according to claim 2, characterized in that: The portion of the main reinforcing bar (21) and sonic logging pipe (22) located in the over-irrigation area (24) needs to be wrapped with an elastic material layer (23).

5. The method for removing over-grouting of large-diameter pile heads based on a split structure according to claim 2, characterized in that: After the pile head steel casing (1) is connected with the retained pile foundation steel casing (2) and the main reinforcement cage (21), the top elevation of the main reinforcement / sonic logging sleeve (4) should be higher than the sum of the design elevation of the pile top and the height of the over-grown portion.

6. The method for removing over-grouting of large-diameter pile heads based on a split structure according to claim 1, characterized in that: Before construction, concrete release agent was applied to the inner wall of the pile head steel casing (1), the outer side of the casing, the upper and lower surfaces of the bottom ring, and the surface of the fan-shaped slider (5) in the bottom interlayer (33) of the pile head steel casing.

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