A pile head cutting system for a cast-in-place pile

Abstract

The application provides a pile head cutting system for a cast-in-place pile, and relates to the technical field of cast-in-place pile production. The cutting system comprises a prefabricated multi-compartment partition plate and an automatic cutting device. The prefabricated multi-compartment partition plate is built in the cast-in-place pile along with the reinforcement cage, is integrally sleeved at one end of the reinforcement cage, seals the end face and the outer wall of the reserved reinforcement of the pile head, and forms a placement cavity in the interior of the reinforcement cage. The automatic cutting device is formed with a cutting rope loop that can be inserted into the placement cavity, and the cutting rope loop is formed with a plurality of cutting portions along the length direction. The hardness of the cutting portions is greater than that of the concrete. The automatic cutting device drives the cutting rope loop to contract along the radial direction of the placement cavity and to displace along the circumferential direction of the placement cavity. The pile head efficient cutting system can realize efficient and silent cutting of the over-poured concrete of the pile head under the premise that the reinforcement in the pile head area is effectively protected from being damaged during the cutting stage, and the pile top is flat after cutting, without subsequent finishing.

Description

Technical Field

[0001] This invention relates to the field of cast-in-place pile production technology, and specifically to a cast-in-place pile head cutting system. Background Technology

[0002] Cast-in-place piles have advantages such as strong adaptability, large adjustable space for pile geometry and single pile bearing capacity, and the ability to penetrate various hard interlayers, embedded rocks and enter various hard bearing layers. They are widely used in pile foundations for large-scale projects such as high-rise buildings and bridges.

[0003] During the pouring of cast-in-place pile concrete, sediment at the pile top and impurities deposited in the slurry during the pouring process will form a certain thickness of laitance on the concrete surface. To ensure the strength of the concrete at the pile top, measures are taken to pour the concrete 0.5-1.0m above the design elevation of the pile top, so as to ensure the compactness of the concrete at the pile top under the self-weight of the over-poured part and that the concrete at the pile head is free of slurry. Before the construction of the superstructure of the pile foundation, the over-poured part needs to be removed so that the reinforcing steel above the pile top elevation is exposed.

[0004] Currently, there are two main methods for removing over-irrigated pile heads: manual removal using pneumatic picks and mechanical removal using hydraulic pile head breakers. Manual removal using pneumatic picks is labor-intensive, inefficient, and generates significant environmental noise, and also poses high personal safety risks. Although hydraulic pile head breakers can effectively solve these problems, improper operation can still result in cracks in the pile head or deformation or even damage to the main reinforcement bars in the over-irrigated area. Furthermore, leveling is required after the pile head is broken.

[0005] Furthermore, with China's goals of achieving carbon peaking and carbon neutrality, energy pile technology based on shallow geothermal energy has received widespread attention from engineering professionals. Energy piles embed heat exchange pipes from a ground source heat pump system within the pile body, with the pile simultaneously serving as a load-bearing and heat exchanger – a novel type of foundation. Cast-in-place piles, as the main type of energy pile, typically employ a method of burying heat exchange pipes bound to a reinforcing cage. When removing these energy piles, whether manually or using a hydraulic pile head crusher for overfilling, deformation of the heat exchange pipes is difficult to avoid, potentially leading to crushing damage and affecting the normal use of the energy pile.

[0006] Therefore, a new, efficient cutting solution for cast-in-place pile heads is needed to address the problems encountered when chiseling and breaking existing pile heads. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to propose a pile head cutting system for cast-in-place piles, the specific solution of which is as follows:

[0008] A pile head cutting system for cast-in-place piles includes a reinforcing cage coaxially arranged inside the pile with its central axis as the center. The portion of the reinforcing cage extending beyond the pile top is designated as pre-reserved reinforcing bars for the pile head. The cutting system comprises a prefabricated multi-compartment partition and an automatic cutting device.

[0009] The prefabricated multi-compartment partition can be installed in the cast-in-place pile along with the steel cage, and is fitted as a whole onto one end of the steel cage to seal the end face and outer wall of the reserved steel bars at the pile head;

[0010] The prefabricated multi-compartment partition is located inside the steel cage to form a placement cavity, which is set as an annular inner cavity coaxial with the steel cage;

[0011] An automatic cutting device is formed with a cutting rope loop that can be inserted into the placement cavity. The cutting rope loop has several cutting sections along its length. The hardness of the cutting sections is greater than that of concrete. The automatic cutting device drives the cutting rope loop to retract radially along the placement cavity and to move circumferentially along the placement cavity.

[0012] Furthermore, the prefabricated multi-compartment partition includes, from the inside out, three coaxially connected enclosed inner compartments, a top-enclosed intermediate compartment, and an enclosed outer compartment, all of which are cylindrical.

[0013] The enclosed inner compartment is fitted to the inner ring of the steel cage, the enclosed outer compartment is fitted to the outer ring of the steel cage, and the top enclosed intermediate compartment is fitted to the end face of the steel cage.

[0014] Furthermore, the height of the enclosed inner compartment is H1, where H1 = H0 + H2 cm, and the radial width is R1, where R1 is greater than the diameter of the cutting rope loop.

[0015] The height of the top-enclosed intermediate compartment is H2cm, and the radial width is R2, where R2 = R0 + 0.5cm, and R0 is the design diameter of the reinforcing steel.

[0016] The height of the enclosed outer compartment is H3, where H3 = H1, and the radial width is R3, which is less than the design width of the steel reinforcement protective layer.

[0017] Furthermore, the cut rope loops are made of diamond beaded rope.

[0018] Furthermore, the automatic cutting device also includes a drive wheel, a power mechanism, and an automatic tightening mechanism;

[0019] The power mechanism is connected to the drive wheel and can drive the drive wheel to rotate. The outer wall of the drive wheel has a toothed groove for the diamond bead rope to be fitted. The diamond bead rope is engaged with the toothed groove and both ends extend outward to form two cut sections of a certain length. The two ends of the two cut sections can be joined together to form a cut rope loop.

[0020] The automatic tightening mechanism contacts the two cutting segments respectively, and can push the cutting segments to open or close to shorten the length of the cutting segments in the placement cavity.

[0021] Furthermore, the automatic tightening mechanism includes a fixed wheel, a pulley, a stepper motor with gears, and a guide rail with racks;

[0022] The guide rail is equipped with two stepper motors spaced apart. The gears of the stepper motors mesh with the racks on the guide rail, and each stepper motor is equipped with a pulley.

[0023] The guide rail is fixed between two stepper motors and has two spaced fixed wheels.

[0024] One end of the diamond beaded cord is wound in an S-shape around a pulley and a fixed pulley.

[0025] Furthermore, the guide rail is arc-shaped and located on one side of the cast-in-place pile, coaxially arranged with the pile.

[0026] Furthermore, a protective bearing is fitted onto the steel bar near the fixed wheel, and the outer wall of the protective bearing has a groove.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) By setting up prefabricated multi-compartment partitions, the prefabricated multi-compartment partitions are installed on the top of the steel cage before the steel cage is hoisted, so that the reserved steel bars at the pile head are wrapped by the prefabricated multi-compartment partitions. When the concrete is poured, the prefabricated multi-compartment partitions can protect the reserved steel bars. After that, the cast-in-place pile is over-poured.

[0029] When it is necessary to remove the over-filled portion of the cast-in-place pile, since the precast multi-compartment partition of the present invention is cast together with the reinforcing cage in the cast-in-place pile, firstly, the over-filled portion is cut along the cutting surface flush with the end face of the reserved reinforcing bar at the pile head. While removing some plain concrete, the precast multi-compartment partition is opened to open the placement cavity to the outside. The cutting rope is placed at the bottom of the placement cavity. Under the power of the automatic cutting device, the cutting rope gradually tightens and gradually cuts the precast multi-compartment partition and plain concrete in the inner circle of the reinforcing cage along another cutting surface that is lower than the height of the reserved reinforcing bar at the pile head.

[0030] Finally, the remaining concrete cover of the pile head and the precast multi-compartment partitions on the outer ring of the reinforcing cage can be cut with a handheld cutting machine. Since there are precast multi-compartment partitions between the reinforcing cage and the concrete cover, the reserved reinforcing bars at the pile head will not be damaged by the handheld cutting machine.

[0031] In summary, by gradually tightening the cutting rope loop, the concrete inside the rebar cage is cut off, resulting in a smooth cut surface that eliminates the need for subsequent pile top trimming. Furthermore, the cutting rope loop gradually moves away from the rebar cage during the cutting process, which, compared to existing technologies, effectively protects the rebar in the pile head area from damage during the cutting stage.

[0032] (2) Based on the principle of the hardness difference between diamond and concrete, the present invention uses a motor drive to drive the diamond bead rope to cut concrete under the action of friction. Compared with existing pneumatic picks and hydraulic pile head breakers, the environmental noise of the operation process of the present invention is greatly reduced, thereby reducing noise pollution.

[0033] (3) The hydraulic pile head crusher has a complex overall structure. Compared with the hydraulic pile head crusher in the prior art, the automatic cutting device of the present invention has a simple overall mechanical structure and occupies less space. Although the automatic cutting device needs to be used in conjunction with the prefabricated multi-compartment partition that is pre-set inside the cast-in-place pile, the prefabricated multi-compartment partition can not only separate the pre-reserved steel bars and concrete in the process of over-pouring concrete, but also limit the diamond bead rope in the cutting process to complete the cutting with the automatic cutting device. Attached Figure Description

[0034] Figure 1 This is a plan view of the pile head cutting system of the present invention during operation;

[0035] Figure 2 This is a cross-sectional view of the pile head area of ​​a cast-in-place pile;

[0036] Figure 3 A cross-sectional view of the precast multi-compartment partition and the steel reinforcement reserved for the pile head;

[0037] Figure 4 This is a schematic diagram showing the contact between the drive wheel and the diamond beaded rope.

[0038] Reference numerals in the attached diagram: 1. Cast-in-place pile; 2. Precast multi-compartment partition; 21. Enclosed inner compartment; 211. Placement cavity; 22. Top-enclosed intermediate compartment; 23. Enclosed outer compartment; 3. Diamond beaded rope; 4. Cutting section; 5. Drive wheel; 51. Protrusion; 52. Tooth groove; 6. Power mechanism; 7. Automatic tightening mechanism; 71. Fixed wheel; 72. Pulley; 73. Stepper motor; 74. Guide rail; 8. Reinforcing steel bar reserved at the pile head; 9. Protective bearing. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0040] A cast-in-place pile is a type of pile formed by drilling a hole using drilling machinery and then pouring concrete into the hole (or by first placing a reinforcing cage in the hole). When constructing a cast-in-place pile 1 with a reinforcing cage, to ensure the strength of the concrete at the pile top, a measure is taken to pour concrete 0.5-1.0m above the design elevation of the pile top. Before constructing the superstructure of the pile foundation, the excess concrete must be removed to expose the reinforcing steel above the pile top elevation. In this embodiment, the height of the excess concrete can be selected within the range of 0.5-1.0m without specific limitations. Since the reinforcing cage is integrally cast in concrete, for ease of description, the height of the reinforcing steel exceeding the design elevation of the pile top is designated as H0. This H0 is not specifically limited, and this portion of the reinforcing steel can be simply referred to as the pile head reserved reinforcing steel 8.

[0041] In view of the shortcomings of existing methods for removing pile heads in cast-in-place piles, this invention provides a pile head cutting system for cast-in-place piles. This system can achieve efficient and quiet cutting of over-poured concrete in the pile head while effectively protecting the reinforcing steel in the pile head area from damage during the cutting stage. Moreover, the pile top is flat after cutting and requires no subsequent trimming.

[0042] To achieve the above functions, the cutting system consists of two parts: a prefabricated multi-compartment partition 2 and an automatic cutting device that performs the actual cutting operation. The prefabricated multi-compartment partition 2 is used to wrap and protect the reinforcing bars that extend beyond the top H0 of the pile before the concrete is poured into the reinforcing cage during the construction of the cast-in-place pile 1. Another function is to assist the automatic cutting device in positioning and cutting during the cutting stage.

[0043] See Figure 2 The prefabricated multi-compartment partition 2 is cylindrical in shape and made of PVC. Structurally, it consists of three independent compartments, specifically three coaxially connected closed inner compartments 21, a top-closed middle compartment 22, and a closed outer compartment 23. The three compartments are also cylindrical, and their enclosure is achieved by hollow interiors and sealed end faces, which reduces the weight of the entire compartment. To accommodate the specifications of the reinforcing bars exceeding the pile top H0, the height of the enclosed inner chamber 21 is H1, where H1 = H0 + H2cm, and the radial width is R1, which is greater than the diameter of the cutting rope loop in the automatic cutting device. The height of the top enclosed intermediate chamber 22 is H2cm, which is set to 10cm in this embodiment, and the radial width is R2, where R2 = R0 + 0.5cm, and R0 is the design diameter of the reserved reinforcing bar 8 at the pile head. The height of the enclosed outer chamber 23 is H3, where H3 = H1, and the radial width is R3, which is less than the design width of the reinforcing bar protective layer. The reinforcing bar protective layer refers to the concrete covering the area from the outer edge of the reinforcing bar to the surface of the component to protect the reinforcing bar. In this embodiment, it is the width from the outer edge of the reserved reinforcing bar 8 at the pile head to the surface of the cast-in-place pile 1. For example, when the design thickness of the reinforcing bar protective layer is 5.0cm, R3 can generally be set to 4.0cm.

[0044] It should be noted that although the enclosed inner compartment 21, the top enclosed intermediate compartment 22, and the enclosed outer compartment 23 are different in size and specifications, when they are assembled into the prefabricated multi-compartment partition 2, the side walls of the three are fixedly connected in sequence, and the two end faces of the prefabricated multi-compartment partition 2 along the axial direction are uniformly on the same plane.

[0045] like Figure 3 As shown, before hoisting the steel cage, the prefabricated multi-compartment partition 2 is installed on the top of the steel cage. Specifically, the pre-reserved steel bars 8 at the pile head are inserted into the gap between the closed inner compartment 21 and the closed outer compartment 23. At the same time, the end face of the pre-reserved steel bars 8 at the pile head abuts against the top closed intermediate compartment 22. Figure 2 The figure shows a cross-sectional view of the pile head area of ​​the cast-in-place pile 1. As can be seen from the figure, the cross-section of the precast multi-compartment diaphragm 2 is U-shaped. At this time, the outer wall of the precast steel bar 8 at the pile head within the range of H0 along its length is wrapped by the closed inner compartment 21 and the closed outer compartment 23. It should be noted that the gap between the steel bar and the precast multi-compartment diaphragm 2 is filled with clay to improve the stability between the steel cage and the precast multi-compartment diaphragm 2.

[0046] After the steel cage is hoisted, concrete is poured. The precast multi-compartment diaphragm 2 protects the pre-reserved steel bars 8 at the pile head, preventing direct contact with the concrete. To ensure the strength of the concrete at the pile top, over-pouring of concrete is performed. The over-pouring concrete only contacts the outer surface of the precast multi-compartment diaphragm 2. When removing the over-pouring portion later, since there is no connection strength between the pre-reserved steel bars 8 at the pile head and the precast multi-compartment diaphragm 2, it is only necessary to separate the precast multi-compartment diaphragm 2 from the pre-reserved steel bars 8 at the pile head. There is no need to cut the concrete from the pre-reserved steel bars 8 at the pile head, thus avoiding damage to the steel bars.

[0047] like Figure 1 As shown, the automatic cutting device has a cutting rope loop that can be controlled to retract and move. The cutting rope loop has several cutting sections along its length, and the hardness of these sections is greater than that of concrete. In the prior art, diamond is the hardest naturally occurring substance. Therefore, in this invention, the cutting rope loop can be made of diamond beaded rope 3, meaning that multiple diamonds are spaced apart on the rope, and the cutting sections on the cutting rope loop correspond to the diamond beads. The specific specifications can be set according to the actual working conditions. To achieve the cutting effect of the diamonds, during the cutting operation, the automatic cutting device is positioned on the adjacent side of the cast-in-place pile 1. It can control the retraction of the cutting rope loop along the radial direction of the cast-in-place pile 1. During the retraction process, the cutting rope loop is displaced and swings relative to the cast-in-place pile 1. Under the action of friction, the diamond beads cut the over-poured concrete, and the cutting rope loop gradually retracts until the concrete is cut off.

[0048] In this regard, the automatic cutting device, in addition to cutting rope loops, specifically includes a drive wheel 5, a power mechanism 6, and an automatic tightening mechanism 7. The power mechanism 6 can be a drive motor, whose output shaft is coaxially and fixedly connected to the drive wheel 5, providing rotational torque to the drive wheel 5, thereby driving the drive wheel 5 to rotate. Figure 4 As shown, on the outer periphery of the drive wheel 5, there are multiple protrusions 51 arranged in a ring. Between two adjacent protrusions 51, there are grooves 52 for diamond beads to be embedded. The diamond bead rope 3 is engaged with the grooves 52, so that when the drive wheel 5 rotates, it applies additional force to the diamond beads through the protrusions 51, driving the diamond bead rope 3 to work.

[0049] After the diamond beaded rope 3 is installed on the drive wheel 5, both ends of it extend outward to form two cutting sections 4 of a certain length. By setting a joint, the two ends of the two cutting sections 4 can be joined to form a closed loop, that is, a cutting rope loop. Since the diameter of the cutting rope loop is much larger than the diameter of the grouting pile 1, an automatic tightening mechanism 7 is needed to adjust the cutting rope loop to a suitable size.

[0050] The automatic tightening mechanism 7 specifically includes fixed wheels 71, pulleys 72, geared stepper motors 73, and rack-and-pinion guide rails 74. The guide rails 74 are arc-shaped and located on one side of the cast-in-place pile 1, coaxially arranged with the pile to reduce space occupation. Two spaced-apart stepper motors 73 are mounted on the guide rails 74, symmetrically arranged with the drive wheel 5 as the center point. The gears of the stepper motors 73 mesh with the racks on the guide rails 74. Each stepper motor 73 is equipped with a pulley 72, which provides power to the gears, thereby moving the pulleys 72 along the guide rails 74. Two spaced-apart fixed wheels 71 are fixedly connected to the guide rails 74 between the two stepper motors 73, also symmetrically arranged with the drive wheel 5 as the center point.

[0051] When the automatic tightening mechanism 7 is used in conjunction with the diamond beaded rope 3, one end of the cutting segment 4 passes in an S-shape around a pulley 72 and a fixed wheel 71. It should be noted that, since the pulleys 72 and 71 will contact the cutting segment 4, to prevent diamond wear on the wheels, the outer walls of the pulleys 72 and 71 that contact the cutting segment 4 are provided with protrusions 51 and grooves 52 consistent with those of the drive wheel 5. When the automatic tightening mechanism 7 is working, as the stepper motor 73 moves along the guide rail 74, if the two pulleys 72 are relatively far apart, under the limiting action of the fixed wheel 71, the length of the cutting segment 4 between the pulleys 72 and 71, and between the pulleys 72 and 71, will gradually lengthen. Conversely, if the two pulleys 72 are relatively close, the length of the cutting segment 4 between the pulleys 72 and 71, and between the pulleys 72 and 71, will gradually shorten, thereby adjusting the tension of the diamond beaded rope 3.

[0052] The specific operating method of this cutting system is as follows:

[0053] As shown in the figure, the first step is to make an initial cut along the cutting line 1 to the overfilled part. The initial cut is made along the cutting surface flush with the end face of the steel bar. At this time, the top closed intermediate compartment 22 of the precast multi-compartment partition 2 is cut off along with the concrete. While removing some of the plain concrete, the closed inner compartment 21 and closed outer compartment 23 of the precast multi-compartment partition 2 are opened with skylights. That is, the two end faces of the closed inner compartment 21 and closed outer compartment 23 are removed. At the same time, two openings are made on the side walls of the closed inner compartment 21 and closed outer compartment 23 to facilitate the cutting segment 4 to enter the placement cavity 211 and extend out of the placement cavity 211. At this time, the cavity inside the closed inner compartment 21 is open to the outside, forming the placement cavity 211 for placing the cutting segment 4. The placement cavity 211 is a circular inner cavity.

[0054] The second step is to place the two cutting segments 4 at the bottom of the placement cavity 211. At this time, the height of the cutting segments 4 is flush with the end of the pre-reserved steel bar 8 at the pile head. The ends of the two cutting segments 4 are joined together with a connector to form a cutting coil. The drive motor and stepper motor 73 are turned on to shorten the length of the cutting segments 4 in the placement cavity 211. The cutting coil is gradually tightened, and the over-filled part can be cut a second time along the cutting line 2 in the figure. That is, the pile core plain concrete of the over-filled part is cut off along another cutting surface that is lower than the height of the previous cutting surface H0.

[0055] The final step involves using a handheld cutter to cut the remaining protective concrete layer of the pile head and the precast multi-compartment slab 2, and then washing away the clay that was originally filled in.

[0056] In the second step, since all the reinforcing bars are in the gap between the closed inner chamber 21 and the closed outer chamber 23, the cutting section 4 will pass through the gap when it extends into and out of the placement cavity 211. In the gap, two reinforcing bars near the fixed wheel 71 are fitted with protective bearings 9. The outer circumference of the bearing is a groove. When cutting the pile head, the bearing is fitted on the pile head reserved reinforcing bar 8 to prevent the diamond bead rope 3 from contacting the pile head reserved reinforcing bar 8 and causing wear on the pile head reserved reinforcing bar 8.

[0057] In summary, in the first step, since the top surface of the over-filled section is much higher than the plane where the end face of the pre-reserved reinforcing bar 8 of the pile head is located, the initial cut will not affect the internal pre-reserved reinforcing bar 8 of the pile head. A hydraulic pile head crusher can be used, and even if the cut surface is uneven, it will not have any impact. In fact, the most important step is the second step. During the secondary cutting process, as can be seen from the figure, except for the two reinforcing bars with protective bearings 9, the cutting rope loop will not come into contact with other reinforcing bars on the reinforcing cage, thus effectively protecting the reinforcing bars in the pile head area from damage during the cutting stage.

[0058] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for using a pile head cutting system for cast-in-place piles, wherein a reinforcing cage is coaxially arranged inside the cast-in-place pile (1) with its central axis as the center, and the portion of the reinforcing cage extending beyond the top of the pile is designated as a pre-reserved reinforcing bar (8) for the pile head, characterized in that, The pile head cutting system includes a prefabricated multi-compartment partition (2) and an automatic cutting device. The prefabricated multi-compartment partition (2) is installed in the cast-in-place pile (1) as a steel cage is placed inside, and is fitted onto one end of the steel cage to seal the end face and outer wall of the reserved steel bar (8) at the pile head; The prefabricated multi-compartment partition (2) includes three coaxially connected closed inner compartments (21), a top closed middle compartment (22), and a closed outer compartment (23) from the inside to the outside. All three are cylindrical and their side walls are fixed in sequence. Each compartment is hollow inside and closed at the end. The closed inner compartment (21) is fitted to the inner ring of the steel cage, the closed outer compartment (23) is fitted to the outer ring of the steel cage, and the top closed middle compartment (22) is fitted to the end face of the steel cage. Before hoisting the steel cage, the prefabricated multi-compartment partition (2) is installed on the top of the steel cage. Specifically, the pre-reserved steel bars (8) at the pile head are inserted into the gap between the closed inner compartment (21) and the closed outer compartment (23). The gap between the steel bars and the prefabricated multi-compartment partition (2) is filled with clay to fill the remaining space. The prefabricated multi-compartment partition (2) is located inside the steel cage and forms a placement cavity (211). The placement cavity (211) is set as an annular inner cavity coaxial with the steel cage. An automatic cutting device is formed with a cutting rope loop that can be inserted into the placement cavity (211). The cutting rope loop has several cutting parts along its length. The hardness of the cutting parts is greater than that of concrete. The automatic cutting device drives the cutting rope loop to retract radially along the placement cavity (211) and to move circumferentially along the placement cavity (211). The method of use includes the following steps: The first step is to make an initial cut along the cutting line to the overfilled part. The initial cut is made along the cutting surface flush with the end face of the steel bar. At this time, the top closed intermediate compartment (22) of the precast multi-compartment partition is cut off as the concrete is removed. While cleaning up some plain concrete, the closed inner compartment (21) and closed outer compartment (23) of the precast multi-compartment partition are opened with skylights. That is, the two end faces of the closed inner compartment (21) and closed outer compartment (23) are removed. At the same time, two openings are made on the side walls of the closed inner compartment (21) and closed outer compartment (23) to facilitate the cutting segment to enter the placement cavity (211) and extend out of the placement cavity (211). At this time, the cavity inside the closed inner compartment (21) is open to the outside, forming the placement cavity (211) for placing the cutting segment. The second step is to place the two cutting segments into the bottom of the placement cavity (211). At this time, the height of the cutting segments is flush with the end of the pre-reserved steel bar (8) at the pile head. The ends of the two cutting segments (4) are joined together with a joint to form a cutting coil. The length of the cutting segments in the placement cavity (211) is shortened. The cutting coil is gradually tightened so that the over-filled part can be cut a second time. The third step involves using a handheld cutting machine to cut the remaining protective concrete layer of the pile head and the precast multi-compartment partition (2), and washing away the clay that was originally filled.

2. The method of using the pile head cutting system according to claim 1, characterized in that, The height of the enclosed inner chamber (21) is H1, H1 = H0 + H2cm, the radial width is R1, R1 is greater than the diameter of the cutting rope loop, and H0 is the design height of the steel bars in the steel cage exceeding the top of the pile. The height of the top-closed intermediate compartment (22) is H2cm, and the radial width is R2, R2=R0+0.5cm, where R0 is the design diameter of the steel bar; The height of the enclosed outer chamber (23) is H3, H3 = H1, and the radial width is R3, which is less than the design width of the steel reinforcement protective layer.

3. The method of using the pile head cutting system for cast-in-place piles according to claim 2, characterized in that, The cutting loops are made of diamond beaded rope (3).

4. The method of using the pile head cutting system according to claim 3, characterized in that, The automatic cutting device also includes a drive wheel (5), a power mechanism (6), and an automatic tightening mechanism (7); The power mechanism (6) is connected to the drive wheel (5) and can drive the drive wheel (5) to rotate. The outer wall of the drive wheel (5) has a tooth groove (52) for the diamond bead rope (3) to fit. The diamond bead rope (3) meshes with the tooth groove (52) and both ends extend outward to form two cutting sections (4) of a certain length. The two ends of the two cutting sections (4) can be joined to form a cutting rope loop. The automatic tightening mechanism (7) contacts the two cutting segments (4) respectively, and can push the cutting segments (4) to open or close to shorten the length of the cutting segments (4) in the placement cavity (211).

5. The method of using the pile head cutting system for cast-in-place piles according to claim 4, characterized in that, The automatic tightening mechanism (7) includes a fixed wheel (71), a pulley (72), a stepper motor with gears (73), and a guide rail with racks (74); The guide rail (74) is provided with two stepper motors (73) spaced apart. The gears of the stepper motors (73) mesh with the racks on the guide rail (74). Each stepper motor (73) has a pulley (72) mounted on its gear. The guide rail (74) is located between two stepper motors (73) and has two spaced fixed wheels (71) fixedly connected to it; One end of the diamond beaded cord (3) is wrapped in an S-shape around a pulley (72) and a fixed pulley (71).

6. The method of using the pile head cutting system according to claim 5, characterized in that, The guide rail (74) is arc-shaped and is located on one side of the cast-in-place pile (1), and is coaxial with the cast-in-place pile (1).

7. The method of using the pile head cutting system according to claim 6, characterized in that, A protective bearing (9) is fitted on the steel bar near the fixed wheel (71), and a groove is provided on the outer wall of the protective bearing (9).

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