A pile head treatment device for cast-in-place piles and a pile head treatment method using the same.

Abstract

The present invention provides a pile head processing device for cast-in-place piles and a pile head processing method using the same, which enable the installation of each bag-shaped object to be performed easily and quickly, thereby improving work efficiency during installation. [Solution] The present invention relates to a pile head processing device X for cast-in-place piles, in which concrete is poured into pile holes through which a reinforcing cage 3 consisting of multiple main reinforcing bars 31, 32 and hoop reinforcing bars 33 is inserted, and the excess concrete at the top of the pile head is crushed and removed by the expansion action of a static crushing agent placed along the crushing plan line. The static crushing agent 21 is individually contained in multiple permeable bag-shaped objects 2. A roughly hexagonal frame-shaped jig 4 is divided equally into two parts in the circumferential direction, and each bag-shaped object 2 is attached to the divided jig piece 41 by cable ties, so as to follow the inner circumferential surface of the temporary hoop reinforcing bars 33T for installation that are on the crushing plan line of the cast-in-place pile. Each divided jig piece 41 is then locked to the temporary hoop reinforcing bars 33T for installation by locking parts 421 to 424.

Description

Technical Field

[0001] The present invention relates to a pile head treatment device for cast-in-place piles and a pile head treatment method using the same. In particular, it relates to a method of causing a cracking phenomenon based on a static crusher in concrete hardened by the expansion action of the static crusher, and crushing and removing excess concrete on the pile head.

Background Art

[0002] Generally, as foundation piles for buildings such as buildings and bridges, so-called cast-in-place piles are used, in which a pile hole is excavated in the ground on site, and fresh concrete is filled into the pile hole to form a reinforced concrete pile. In the construction of cast-in-place piles, first, a cylindrical pile hole is excavated in the ground using an earth drill or the like. When the excavation of the pile hole is completed, a steel cage assembled in a cylindrical shape by a plurality of main reinforcing bars and a plurality of hoop reinforcing bars is inserted into the pile hole. Then, fresh concrete is driven into the pile hole through a tremie pipe with an outer diameter of about 250 mm inserted through the center of the pile hole, thereby constructing a cast-in-place pile made of reinforced concrete.

[0003] When driving fresh concrete into a cast-in-place pile, as the top surface of the concrete rises, the soil particles deposited at the bottom of the pile hole are pushed up and discharged to the upper part of the pile hole. Therefore, at the stage when the driving of the concrete is completed, the concrete near the top end is regarded as poor concrete mixed with soil particles. For this reason, in the case of cast-in-place piles, it is necessary to drive the fresh concrete higher than the designed pile top end height by an extra amount, and after the upper part higher than the designed pile top end height hardens as excess concrete, it is removed.

[0004] From this point, in order to remove the excess part of the pile head, the designed pile top end height or just above it is set as the crushing planned line, a static crusher is arranged on this line, and the static crushing phenomenon of concrete due to the expansion action of this static crusher is utilized to perform crushing and removal without the concrete chopping work accompanied by noise (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 59-91214 [Overview of the project] [Problems that the invention aims to solve]

[0006] Incidentally, when installing static crushing agent along the crushing plan line set at or directly above the design pile top height of a cast-in-place pile, the static crushing agent is contained in a permeable bag-like object, and this bag-like object containing the static crushing agent is attached to the corresponding portion of the reinforcing cage that corresponds to the crushing plan line.

[0007] In that case, the bag-like objects containing the static crushing agent are not light, and the installation work of attaching them to the main reinforcement and hoop reinforcement in the areas corresponding to the crushing plan lines of the rebar cage is extremely cumbersome. Furthermore, the installation of multiple bag-like objects takes a considerable amount of time, resulting in very poor work efficiency.

[0008] The present invention has been made in view of the above, and its objective is to provide a pile head processing device for cast-in-place piles and a pile head processing method using the same, which can improve work efficiency during installation by enabling the installation of each bag-shaped object to be carried out easily and quickly. [Means for solving the problem]

[0009] To achieve the above objective, the present invention is based on a pile head processing device for cast-in-place piles, in which the excess pile head portion of a cast-in-place pile made of concrete, which is driven into a pile hole through which a reinforcing cage assembled in a cylindrical shape by multiple main reinforcing bars and multiple hoop reinforcing bars is inserted, is crushed and removed by the expansion action of a static crushing agent placed on a crushing design line set at or directly above the design pile top height of the cast-in-place pile. Furthermore, the static crushing agent is individually contained in multiple permeable bag-shaped objects.The bag-shaped objects are then attached by attachment means to divided jig pieces, which are obtained by dividing a frame-shaped jig that is positioned along the inner circumference of a temporary hoop reinforcing bar for installation, which is placed on the crushing plan line of the reinforcing cage corresponding to the crushing design line of the cast-in-place pile, in the circumferential direction.Furthermore, each of the divided jig pieces to which the bag-shaped objects are attached is locked to the temporary hoop reinforcing bar for installation by a locking part.

[0010] Furthermore, it is preferable to provide each of the division jig pieces with an additional mounting portion positioned closer to the center of the temporary hoop reinforcement for mounting than the division jig piece itself, and to attach the bag-shaped object to this mounting portion using the mounting means.

[0011] In contrast, the locking portion is formed in a roughly grid shape by four reinforcing bars extending in the in-plane direction of the temporary hoop reinforcement for mounting, such that both ends of the locking portion straddle the temporary hoop reinforcement for mounting. An additional mounting portion is provided in the portion surrounded by each of the reinforcing bars, positioned closer to the center of the temporary hoop reinforcement for mounting than each of the dividing jig pieces, and the bag-shaped object may also be attached to this mounting portion by the mounting means.

[0012] Furthermore, a fastening device for attaching the bag-shaped object by binding may be used as the attachment means.

[0013] Furthermore, each of the division jig pieces may be provided with a wire to restrain the locking portion in a state where it is locked to the temporary hoop reinforcement for mounting.

[0014] Furthermore, it is preferable to secure each of the divided jig pieces to the temporary hoop reinforcement for mounting at three or more points using the locking portion, so as to ensure the equilibrium of each bag-shaped object with respect to the temporary hoop reinforcement for mounting, and to hold them in the in-plane direction of the temporary hoop reinforcement for mounting.

[0015] In contrast, to achieve the above objective, the present invention is based on a pile head treatment method using a pile head treatment device for cast-in-place piles, in which the excess pile head portion of a cast-in-place pile made of concrete, which is driven into a pile hole through which a reinforcing cage assembled in a cylindrical shape by a plurality of main reinforcing bars and a plurality of hoop reinforcing bars is inserted, is crushed and removed by the expansion action of a static crushing agent placed on a crushing design line set at or directly above the design pile top height of the cast-in-place pile. The static crushing agent is individually contained in a plurality of permeable bag-shaped objects. Next, each of the bag-shaped objects is attached by means of attachment to a divided jig piece obtained by dividing a frame-shaped jig, which is positioned along the inner circumferential surface of the temporary hoop reinforcing bars for installation that are placed on the reinforcing cage corresponding to the crushing design line of the cast-in-place pile, in the circumferential direction. Then, each of the divided jig pieces to which each of the bag-shaped objects is attached is locked to the temporary hoop reinforcing bars for installation by locking parts. [Effects of the Invention]

[0016] In short, when attaching the static crushing agent to the temporary hoop reinforcement for attaching the reinforcing cage, which is positioned on the crushing plan line set at or directly above the design pile top height of the cast-in-place pile, a frame-shaped jig that follows the inner circumference of the temporary hoop reinforcement is divided into multiple sections in the circumferential direction. Multiple permeable bag-shaped objects, each containing the static crushing agent, are attached to these sections using attachment means, and then each section of the jig is locked to the temporary hoop reinforcement for attaching the reinforcing cage using a locking mechanism.

[0017] Therefore, the work of attaching each bag-shaped object to the main reinforcement and hoop reinforcement of the reinforcing cage is eliminated, and each bag-shaped object can be easily attached to each segmented jig piece before being locked to the temporary hoop reinforcement for attaching the reinforcing cage. As a result, each segmented jig piece to which multiple bag-shaped objects containing static crushing agent are attached by the attachment means can be attached to the temporary hoop reinforcement for attachment smoothly and quickly, making the attachment work of each bag-shaped object easy and fast, and improving the work efficiency when attaching each bag-shaped object.

[0018] Furthermore, by attaching a bag-like object to the attachment point located closer to the center of the temporary hoop reinforcement than each segmented jig piece using an attachment means, the static crushing phenomenon of concrete caused by the expansion of the static crushing agent can be utilized even closer to the center of the temporary hoop reinforcement. This allows the static crushing effect to be more uniformly distributed within the plane of the temporary hoop reinforcement, enabling efficient crushing and removal of the excess concrete at the pile head.

[0019] Furthermore, four reinforcing bars are secured to the temporary hoop reinforcement for installation, with their ends straddling each other to form a roughly grid shape. Bag-shaped objects are also attached by means of attachment to the attachment points in the areas surrounded by each reinforcing bar, which are closer to the center of the temporary hoop reinforcement than each divided jig piece. This allows the static crushing phenomenon of concrete caused by the expansion of the static crushing agent to be utilized even closer to the center of the temporary hoop reinforcement, and the static crushing effect can be more uniformly distributed within the plane of the temporary hoop reinforcement, enabling efficient crushing and removal of the excess concrete at the pile head.

[0020] Furthermore, by using fasteners as the attachment method, bag-shaped objects can be attached easily and quickly simply by fastening them together, thereby simplifying and speeding up the attachment process for each bag-shaped object.

[0021] Also, by restraining each locking part of the divided jig pieces with a wire rod while being locked to the temporary installation hoop bars for attachment, each divided jig piece can be securely locked to the temporary installation hoop bars for attachment, and the static crushing phenomenon of the concrete due to the expansion action of the static crusher can be surely exhibited on the crushing planned line of the pile head surplus part.

[0022] Furthermore, each divided jig piece is locked at three or more points by the locking part to the temporary installation hoop bars for attachment so that the balance of each bag-like object is ensured, and is held in the in-plane direction of the temporary installation hoop bars for attachment. As a result, each bag-like object is maintained in the in-plane direction of the temporary installation hoop bars for attachment, preventing the occurrence of the static crushing phenomenon below the crushing planned line of the pile head surplus part, which is very advantageous for ensuring the quality of the driven pile.

Brief Description of the Drawings

[0023] [Figure 1] It is a side view showing a state where a driven pile using the pile head processing device according to the first embodiment of the present invention is formed by concrete placed in a pile hole. [Figure 2] It is a plan view of one of the divided jig pieces obtained by dividing the frame jig of the pile head processing device of FIG. 1 into two. [Figure 3] It is a perspective view of one of the divided jig pieces of FIG. 2. [Figure 4] It is a side view of one of the divided jig pieces of FIG. 2. [Figure 5] It is a plan view of a reinforcing cage showing a state where the two divided jig pieces of FIG. 2 are respectively locked to the temporary installation hoop bars for attachment by the locking parts. [Figure 6] It is a perspective view showing a state where one of the divided jig pieces of FIG. 5 is locked to the temporary installation hoop bars for attachment by the locking part. [Figure 7] It is a plan view of a reinforcing cage showing a state where each bag-like object is respectively attached to each of the divided jig pieces of FIG. 5 by a binding tool. [Figure 8] It is a perspective view showing a state where each bag-like object is respectively attached to one of the divided jig pieces of FIG. 5 by a binding tool. [Figure 9]This is a side view showing the state in which the reinforcing cage in Figure 7 has begun to be lifted by the wire. [Figure 10] Figure 9 is a perspective view showing the reinforcing cage being lifted by wires. [Figure 11] Figure 10 is a side view showing the state in which the reinforcing cage is being lowered by wire and inserted into the surface casing and steel pipe of the pile hole. [Figure 12] This is a side view showing the reinforcing cage in Figure 11 being placed on the steel pipe in the pile hole via a hanger. [Figure 13] This is a plan view of one of the two divided jig pieces of a frame-shaped jig for a pile head processing device for cast-in-place piles according to a second embodiment of the present invention. [Figure 14] This is a perspective view of one of the dividing jig pieces in Figure 13. [Figure 15] This is a side view of one of the dividing jig pieces in Figure 13. [Figure 16] Figure 13 is a plan view of the reinforcing cage showing the two divided jig pieces secured to the temporary hoop reinforcement using their respective locking parts. [Figure 17] This is a plan view of the reinforcing cage, showing each bag-shaped object attached to each segmented jig piece in Figure 16 using fasteners. [Figure 18] This is a plan view of one of the two divided jig pieces of a frame-shaped jig for a pile head processing device for cast-in-place piles according to a third embodiment of the present invention. [Figure 19] This is a perspective view of one of the dividing jig pieces in Figure 18. [Figure 20] This is a side view of one of the dividing jig pieces in Figure 18. [Figure 21] Figure 18 is a plan view showing the two divided jig pieces combined with the mounting part at the locking part for securing them to the temporary hoop reinforcement for mounting. [Figure 22] Figure 21 is a perspective view of the locking mechanism. [Figure 23] Figure 21 is a side view of the locking mechanism. [Figure 24]Figure 18 is a plan view of the reinforcing cage showing the state in which the two divided jig pieces and mounting parts are secured to the temporary hoop reinforcement for mounting by four reinforcing bars formed in a roughly grid shape. [Figure 25] This is a plan view of the reinforcing cage, showing each bag-shaped object attached to each segmented jig piece using fasteners. [Modes for carrying out the invention]

[0024] Hereinafter, a pile head processing device for cast-in-place piles according to the first embodiment of the present invention will be described based on the drawings.

[0025] Figure 1 is a side view showing a state in which a cast-in-place pile has been formed by concrete driven into a pile hole using a pile head processing device according to the first embodiment of the present invention.

[0026] As shown in Figure 1, the pile head processing device X for cast-in-place piles A is used when constructing foundation piles for buildings, bridges, etc., by excavating a pile hole 11 in the ground at the construction site G and filling this pile hole 11 with ready-mixed concrete to form the cast-in-place pile A. In this case, reference numeral 10 denotes a foundation hole for installing a foundation (not shown), which is excavated in a roughly rectangular shape around the cast-in-place pile A after the ready-mixed concrete filled in the pile hole 11 has cured.

[0027] In cast-in-place piles A, when concrete is poured through a tubular surface casing 12 (shown in Figures 11 to 13) inserted along the inner circumference of the pile hole 11 and a steel pipe 13 inserted inside it, soil particles that had accumulated at the bottom of the pile hole 11 are pushed up by the excavation of the pile hole and discharged to the top of the pile hole 11. Therefore, at the stage when the concrete pouring is completed, the concrete near the top is considered to be poor quality concrete mixed with soil particles. For this reason, in the case of cast-in-place piles A, the concrete is poured to a height greater than the design pile top height, so that the concrete above the design pile top height is treated as the pile head excess portion 14 and then crushed and removed after it hardens. At this time, the crushing and removal of the pile head excess portion 14 is carried out quietly by placing a static crushing agent 21 (shown in Figures 7 and 8) on a predetermined crushing plan line M of the cast-in-place pile A and utilizing the static crushing phenomenon of the concrete caused by the expansion action of this static crushing agent 21. In this case, the planned crushing line M for the pile head (cast-in-place pile A) is set to the design pile top height of cast-in-place pile A.

[0028] The static crushing agent 21 used is based on calcium aluminoferrite [(CaO)4-Al2O3-Fe2O3], free calcium oxide (CaO), and magnesium oxide (MgO), with the addition of a retarder such as a borate. The time it takes for hydration expansion pressure to occur can be adjusted by appropriately changing the type and amount of retarder. The static crushing agent 21 is not limited to this, and any agent that can cause static crushing of concrete due to expansion during concrete curing can be used.

[0029] Figure 2 is a plan view of one of the two divided jig pieces of the pile head processing device X shown in Figure 1, Figure 3 is a perspective view of one of the divided jig pieces in Figure 2, and Figure 4 is a side view of one of the divided jig pieces in Figure 2. Furthermore, Figure 5 is a plan view of the reinforcing cage showing the two divided jig pieces from Figure 2 locked to the temporary hoop reinforcement for installation by their respective locking parts.

[0030] As shown in Figures 2 to 5, the static crushing agent 21 is individually contained in multiple permeable bag-like containers 2, 2, ... Each bag-like container 2 is made of a long, narrow cloth bag, and the weight of a single bag containing the static crushing agent 21 is approximately 2 kg. Moisture from the fresh concrete permeates into each bag-like container 2, causing the static crushing agent 21 to slowly expand, thereby creating cracks in the concrete when curing is complete.

[0031] Each bag-shaped object 2 is placed inside a cylindrical reinforcing cage 3. This reinforcing cage 3 comprises a plurality of inner main reinforcing bars 31, 31, ... extending vertically at regular intervals in the circumferential direction, a plurality of outer main reinforcing bars 32, 32, ... extending vertically on the radially outer side of each inner main reinforcing bar 31, and a plurality of hoop reinforcing bars 33, 33, ... extending circumferentially at regular intervals in the vertical direction along each outer main reinforcing bar 32. These main reinforcing bars 31, 32 and hoop reinforcing bars 33 form a cage shape. In this case, each main reinforcing bar 31, 32 is formed in a roughly cylindrical shape, and each hoop reinforcing bar 33 and the temporary hoop reinforcing bar 33T for attachment (described later) are formed in a roughly annular shape by curving a roughly cylindrical steel material into a rounded shape.

[0032] Of the hoop reinforcements 33 of the reinforcing cage 3, the temporary hoop reinforcements 33T for installation, which are located at the part corresponding to the predetermined crushing plan line M on the crushing plan line of the pile head, are fitted with a frame-shaped jig 4 that follows the inner circumference of the hoop reinforcement. The frame-shaped jig 4 is equipped with two equally spaced, roughly trapezoidal frame-shaped divided jig pieces 41, 41 that are separated by 180° phase differences in the circumferential direction.

[0033] Each segmented jig piece 41 comprises a central piece 411 in the longitudinal center and inclined pieces 412, 412 at the longitudinal corner positions of the central piece 411, each inclined at approximately 55° relative to the central piece 411. Each segmented jig piece 41 is also provided with an attachment portion 43 positioned closer to the center of the temporary hoop reinforcement 33T than the segmented jig piece 41. Both longitudinal ends of this attachment portion 43 are connected to the inclined pieces 412 closer to the inside than the central piece 411. In this case, even though the attachment portion 43 is positioned closer to the inside than the central piece 411 of each segmented jig piece 41, there is sufficient space inside it so that the tremie pipe (not shown) for pouring the ready-mix concrete can be inserted with ample clearance, taking into account the swaying caused by the flow during concrete pouring.

[0034] Each segmented jig piece 41 has two elongated holes 44, 44 extending in the longitudinal direction in the central piece 411 and each inclined piece 412, respectively, in order to reduce weight. The mounting piece 43 also has two elongated holes 44, 44 extending in the longitudinal direction.

[0035] Figure 7 is a plan view of the reinforcing cage 3 showing each bag-shaped object 2 attached to each dividing jig piece 41 of Figure 5 using a fastener (attachment means), and Figure 8 is a perspective view showing each bag-shaped object 2 attached to one of the dividing jig pieces 41 of Figure 5 using a fastener.

[0036] As shown in Figures 7 and 8, the central piece 411 and each inclined piece 412 of each dividing jig piece 41 are attached to the central piece 411 and each inclined piece 412, respectively, by fastening bands 46 at both ends in the longitudinal direction. The ends of the bag-shaped object 2 are also attached to the mounting part 43 by fastening bands 46. In this case, the mounting points for the bag-shaped object 2 are increased by the mounting part 43, which is positioned closer to the center of the temporary hoop reinforcement 33T for mounting than each dividing jig piece 41.

[0037] Each segmented jig piece 41 is provided with four locking parts 421, 422, 423, and 424, each consisting of a rod-shaped piece whose base end is joined to the lower surface of the central piece 411 and each inclined piece 412, respectively. The tips of each locking part 421 to 424 are bent downward at approximately 90° so as to be locked from above to the temporary hoop reinforcement 33T for mounting.

[0038] Each segmented jig piece 41 is then secured at four points by its locking parts 421-424 to the temporary hoop reinforcement 33T, ensuring equilibrium of each bag-shaped object 2 with respect to the temporary hoop reinforcement 33T, and is held in the in-plane direction of the temporary hoop reinforcement 33T. In other words, each segmented jig piece 41 is secured at four points to the temporary hoop reinforcement 33T by its locking parts 422 and 423, which are substantially parallel to each other and extend radially outward from both ends of the central piece 411 of each segmented jig piece 41, and by its locking parts 421 and 424, which extend radially outward from both ends of the inclined piece 412 of each segmented jig piece 41, and is held in the in-plane direction of the temporary hoop reinforcement 33T.

[0039] Each locking portion 421 to 424 of each dividing jig piece 41 is equipped with a wire 45 that restrains the tip of each locking portion 421 to 424 in a state where it is locked to the temporary hoop reinforcement 33T for attachment. This wire 45 is stretched between the tips of each locking portion 421 to 424 of each dividing jig piece 41 and the temporary hoop reinforcement 33T for attachment.

[0040] Here, in order to explain the process of driving cast-in-place piles A into pile holes 11, we will first explain the pile head treatment method using the pile head treatment device X for cast-in-place piles A.

[0041] First, in the pile head treatment method using the pile head treatment device X, the static crushing agent 21 is individually contained in multiple permeable bag-shaped objects 2.

[0042] Next, the frame-shaped jig 4 is divided into two circumferential jig pieces 41, 41, and the central piece 411 and each inclined piece 412 of the divided jig pieces are attached to each of the bag-shaped object 2 with cable ties 46. The bag-shaped object 2 is also attached to the attachment part 43 with both ends secured to each of the cable ties 46.

[0043] Then, the ends of the four locking parts 421, 422, 423, and 424, whose base ends are joined to the lower surfaces of the central part 411 and each inclined part 412 of each divided jig piece 41, are secured from above (from the side) to the temporary hoop reinforcement 33T for attaching the reinforcing cage 3, which is laid horizontally at the site G, and are restrained by binding wire 45. At this time, each divided jig piece 41 is secured to the temporary hoop reinforcement 33T for attaching by the four locking parts 421, 422, 423, and 424 at four points and is held in the in-plane direction of the temporary hoop reinforcement 33T.

[0044] Next, an example of the process of driving cast-in-place piles A into pile holes 11 will be explained based on Figures 9 to 13.

[0045] Figure 9 is a side view showing the state in which the reinforcing cage 3 from Figure 7 is being lifted by a wire, and Figure 10 is a perspective view showing the state in which the reinforcing cage 3 from Figure 9 has been lifted by a wire. Furthermore, Figure 11 is a side view showing the state in which the reinforcing cage 3 from Figure 10 is being lowered by a wire and inserted into the surface casing 12 and steel pipe 13 of the pile hole 11. In addition, Figure 12 is a side view showing the state in which the reinforcing cage 3 from Figure 11 has been placed on the steel pipe 13 of the pile hole 11 via a hanger.

[0046] Here, a 5000mm long surface casing 12 is used, and an 8000mm long steel pipe 13 is used. H-shaped steel beams 15, 15 that protrude outward from the outer surface are welded to the upper end of the surface casing 12, and when the surface casing 12 is inserted into the pile hole 11, each H-shaped steel beam 15 abuts against the ground at site G and is supported, thereby restricting further insertion of the surface casing 12 into the pile hole 11. In addition, multiple protruding pieces 16, 16 that protrude outward from the outer surface are provided on the upper end of the steel pipe 13, and when the steel pipe 13 is inserted into the surface casing 12, each protruding piece 16 abuts against the top of the surface casing 12 and is supported, thereby restricting further insertion below the surface casing 12.

[0047] First, in the process of driving the cast-in-place pile A into the pile hole 11 using a pile head processing device, as shown in Figure 9, a chain 51 is attached to the reinforcing cage 3, which is laid horizontally at the site G with each divided jig piece 41 attached to the temporary hoop reinforcement 33T for installation. In other words, the chain 51 is attached to each reinforcing ring 34 attached to the inside of each inner main reinforcement 31 of the reinforcing cage 3 at positions with a 180° phase difference in the circumferential direction, and the cage is lifted via the wires 52 of a crane (not shown). In this case, the reinforcing ring 34 is located slightly (for example, 400mm to 500mm) below the temporary hoop reinforcement 33T for installation.

[0048] Then, as shown in Figure 10, the reinforcing cage 3 is lifted via the wires 52 until it is in a vertical position. Then, as shown in Figure 11, the surface casing 12 is inserted into the pile hole 11, and the H-shaped steels 15, 15 protruding from the outer surface of the surface casing 12 are supported by contacting them with the ground at site G. After that, the steel pipe 13 is inserted into the surface casing 12, and the protruding pieces 16 of the steel pipe 13 are supported by contacting them with the top surface casing 12. After that, the reinforcing cage 3 is lowered via the wires 52 so that it is inserted inside the steel pipe 13. At this time, the reinforcing cage 3 is temporarily held near the top surface of the surface casing 12.

[0049] Then, as shown in Figure 12, the reinforcing ring 34 of the reinforcing cage 3 is fixed to the steel pipe 13 with hangers 54. Specifically, multiple (for example, 3 to 4) L-shaped hangers 54, each having a roughly U-shaped hook portion 541 at its upper end, are used. These hangers 54 are welded to the upper end of the steel pipe 13 at multiple locations (for example, 3 to 4 locations) in the circumferential direction of the steel pipe 13, with the hook portions 541 locked to each hanger 54, and the reinforcing ring 34 is welded to the lower end of each hanger 54.

[0050] Subsequently, the upper end of the reinforcing bar 56, whose lower end is screwed into each of the lock nuts 55 attached near the top of the outer surface of the steel pipe 13, is suspended by a lifting hook 57. When the lower end of the reinforcing cage 3 contacts the bottom surface of the pile hole 11, the top of the reinforcing cage 3 is positioned slightly below the ground level of the site G. At this time, the bag-shaped objects 2,2,... each containing the static crushing agent 21 on each dividing jig piece 41 are kept in the in-plane direction of the temporary hoop reinforcement 33T for attachment so that they are positioned on the crushing plan line M of the pile head of the cast-in-place pile A.

[0051] Subsequently, a tremie pipe is inserted into the reinforcing cage 3 through the mounting parts 43 of each dividing jig piece 41, and ready-mix concrete is poured up to a predetermined height (for example, about 800 mm) above the predetermined crushing plan line M of the pile head. After the start of pouring the ready-mix concrete, each gebin rod 56 is detached from the lock nut 55 of the steel pipe 13 and lifted up by the suspension hook 57, and the surface casing 12 is pulled out. Once the concrete is poured up to the crushing plan line M, the moisture from the ready-mix concrete permeates into each bag-like object 2, and the static crushing agent 21 slowly begins to expand while the concrete is curing, thus curing the concrete.

[0052] Subsequently, as shown in Figure 1, once the concrete curing is complete, a foundation hole 10 is excavated in the ground at site G, approximately 2000mm to 3000mm outward from the periphery of the cast-in-place pile A, forming a roughly rectangular space in plan view, down to below the planned crushing line M at the pile head. At this time, cracks are formed on the planned crushing line M at the pile head due to the expansion of the static crushing agent 21 inside each bag-like object 2. The excess concrete at the pile head (the portion of the pile head with poorly made concrete) that has risen to a predetermined height above the planned crushing line M can be quietly crushed and removed by utilizing the static crushing phenomenon of the concrete caused by the expansion of the static crushing agent 21.

[0053] Therefore, in this embodiment, when attaching the static crushing agent 21 to the temporary hoop reinforcement 33T for installation on the crushing plan line M set at the design pile top height of the cast-in-place pile A, a frame-shaped jig 4 with a roughly hexagonal frame shape that follows the inner circumference of the temporary hoop reinforcement 33T is divided equally into two parts in the circumferential direction, and both ends of a plurality of permeable bag-shaped objects 2,2,... each containing the static crushing agent 21 are attached to each part by cable ties 46. Then, each part of the jig 41 is secured to the temporary hoop reinforcement 33T of the reinforcing cage 3 by four locking parts 421 to 424, and then restrained by binding wire 45.

[0054] Therefore, the work of attaching each bag-shaped object to the main reinforcement and hoop reinforcement of the reinforcing cage is eliminated, and each bag-shaped object 2 can be easily attached to each dividing jig piece 41 before it is locked to the temporary hoop reinforcement 33T for attachment of the reinforcing cage 3. As a result, each dividing jig piece 41, to which each bag-shaped object 2 containing the static crushing agent 21 is bound with a cable tie 46, can be attached smoothly and quickly by being locked to the temporary hoop reinforcement 33T for attachment, making the attachment work of each bag-shaped object 2 easy and quick and improving the work efficiency when attaching each bag-shaped object 2.

[0055] Furthermore, since the bag-shaped object 2 is also attached by a cable tie 46 to the attachment portion 43, which is positioned closer to the center of the temporary hoop reinforcement 33T than each divided jig piece 41, the static crushing phenomenon of concrete due to the expansion action of the static crushing agent 21 can be utilized even closer to the center of the temporary hoop reinforcement 33T. This allows the static crushing effect to be more uniformly distributed within the plane of the temporary hoop reinforcement 33T, enabling efficient crushing and removal of the pile head excess concrete 14.

[0056] Furthermore, each divided jig piece 41 is secured at four points by the locking parts 421 to 424 to the temporary hoop reinforcement 33T for installation, ensuring equilibrium of each bag-shaped object 2 with respect to the temporary hoop reinforcement 33T, and is held in the in-plane direction of the temporary hoop reinforcement 33T. This keeps each bag-shaped object 2 in the in-plane direction of the temporary hoop reinforcement 33T, preventing static crushing below the crushing plan line M of the pile head excess portion 14, which is extremely advantageous in ensuring the quality of the cast-in-place pile A.

[0057] Next, a second embodiment of the present invention will be described based on the drawings.

[0058] In this embodiment, the shape of the frame-shaped jig has been modified. Note that the other components, excluding the frame-shaped jig, are the same as in the first embodiment; therefore, the same reference numerals are used for the same parts, and their detailed descriptions are omitted.

[0059] Figure 13 shows a plan view of one of the two divided jig pieces of a frame-shaped jig for a pile head processing device for cast-in-place piles A according to a second embodiment of the present invention. Figure 14 shows a perspective view of one of the divided jig pieces in Figure 13, and Figure 15 shows a side view of one of the divided jig pieces in Figure 13.

[0060] In other words, as shown in Figures 13 to 15, a frame-shaped jig 6 with a roughly decagonal frame shape is attached to the temporary hoop reinforcement 33T for installation, so as to follow its inner circumferential surface. The frame-shaped jig 6 is equipped with two equally divided jig pieces 61, 61 that are positioned at angular positions with a 180° phase difference between them in the circumferential direction.

[0061] Each dividing jig piece 61 comprises a central piece 611 in the center of its longitudinal direction, first inclined pieces 612, 612 whose longitudinal ends are connected to the corner positions at both longitudinal ends of the central piece 611 and are inclined at approximately 30° with respect to the central piece 611, and second inclined pieces 613, 613 whose longitudinal ends are connected to the other longitudinal end of each first inclined piece 612 and are inclined at approximately 35° with respect to the central piece 611.

[0062] Furthermore, each segmented jig piece 61 is provided with an attachment portion 63 positioned closer to the center of the temporary hoop reinforcement 33T than the segmented jig piece 61. Both longitudinal ends of this attachment portion 63 are connected between the other end of each first inclined piece 612 and one end of each second inclined piece 613, and are positioned closer to the inside than the central piece 611 and each inclined piece 612. In this case, even though the attachment portion 63 is positioned closer to the inside than the central piece 611 and each inclined piece 612 of each segmented jig piece 61, there is sufficient space further inside, so that the tremie pipe for pouring the ready-mix concrete can be inserted with ample clearance, taking into account the swaying caused by the flow during concrete pouring.

[0063] Each segmented jig piece 61 is provided with an elongated hole 64 extending in the longitudinal direction in the central piece 611 and each inclined piece 612, 613, respectively, in order to reduce weight. The mounting portion 63 is also provided with an elongated hole 64 extending in the longitudinal direction.

[0064] Figure 16 shows a plan view of the rebar cage showing the two segmented jig pieces from Figure 13 secured to the temporary hoop reinforcement using the locking parts. Figure 17 also shows a plan view of the rebar cage showing each bag-shaped object attached to each segmented jig piece from Figure 16 using cable ties 46.

[0065] As shown in Figure 17, the bag-shaped object 2 is attached to the first and second inclined pieces 612 and 613 of each dividing jig piece 61, with both ends of the bag-shaped object 2 secured to each inclined piece 612 and 613 by cable ties 46. The bag-shaped object 2 is also attached to the mounting part 63 with both ends of the bag-shaped object 2 secured to the mounting part 63 by cable ties 46. In this case, the mounting area of ​​the bag-shaped object 2 is increased by the mounting part 63, which is positioned closer to the center of the temporary hoop reinforcement 33T for mounting than each dividing jig piece 61.

[0066] Furthermore, as shown in Figure 16, each dividing jig piece 61 is provided with six locking parts 621 to 626, each consisting of a rod-shaped piece whose base end is joined to the lower surface of the central piece 611 and each inclined piece 612, 613. Specifically, each dividing jig piece 61 has approximately parallel locking parts 623, 624 extending radially outward from both ends of the central piece 611 of each dividing jig piece 61, locking parts 622, 625 extending radially outward from the other end of each first inclined piece 612 of each dividing jig piece 61, and locking parts 621, 626 extending radially outward from the other end of each second inclined piece 613 of each dividing jig piece 61. Each of the locking parts 621 to 626 has its tip bent downwards by approximately 90° so that it can be locked onto the temporary hoop reinforcement 33T for attachment from above.

[0067] Each segmented jig piece 61 is secured at six points by locking parts 621 to 626 to ensure equilibrium of each bag-shaped object 2 with respect to the temporary hoop reinforcement 33T for mounting. Specifically, each segmented jig piece 61 is secured at six points to the temporary hoop reinforcement 33T for mounting by locking parts 623 and 624 which are substantially parallel to each other and extend radially outward from both ends of the central piece 611 of each segmented jig piece 61, locking parts 622 and 625 which extend radially outward from the other end of each first inclined piece 612 of each segmented jig piece 61, and locking parts 621 and 626 which extend radially outward from the other end of each second inclined piece 613 of each segmented jig piece 61, and is held in the in-plane direction of the temporary hoop reinforcement 33T for mounting.

[0068] Each locking portion 621 to 626 of each dividing jig piece 61 is equipped with a wire 45 that restrains the tip of each locking portion 621 to 626 in a locked state against the temporary hoop reinforcement 33T for attachment. This wire 45 is stretched between the tips of each locking portion 621 to 626 of each dividing jig piece 61 and the temporary hoop reinforcement 33T for attachment.

[0069] Therefore, in this embodiment, each divided jig piece 61 is secured at six points by the locking parts 621 to 626 to the temporary hoop reinforcement 33T for installation, ensuring equilibrium of each bag-shaped object 2 with respect to the temporary hoop reinforcement 33T, and is held in the in-plane direction of the temporary hoop reinforcement 33T. As a result, each bag-shaped object 2 is kept in the in-plane direction of the temporary hoop reinforcement 33T for installation, which prevents the occurrence of static crushing below the crushing plan line M of the pile head excess portion 14, and is extremely advantageous in ensuring the quality of the cast-in-place pile A.

[0070] Next, a third embodiment of the present invention will be described based on the drawings.

[0071] In this embodiment, the shape of the frame-shaped jig has been modified. Note that the other components, excluding the frame-shaped jig, are the same as in the first embodiment; therefore, the same reference numerals are used for the same parts, and their detailed descriptions are omitted.

[0072] Figure 18 is a plan view of one of the two divided jig pieces of the frame-shaped jig of the pile head processing device X for cast-in-place piles A according to the third embodiment of the present invention, Figure 19 is a perspective view of one of the divided jig pieces of Figure 18, and Figure 20 is a side view of one of the divided jig pieces of Figure 18.

[0073] In other words, as shown in Figures 18 to 20, the divided jig pieces 71, 71, which are formed by equally dividing a frame-shaped jig 7, which has a roughly hexagonal frame shape that follows the inner circumferential surface of the temporary hoop reinforcement 33T for installation, into two pieces at angular positions that are 180° apart in phase in the circumferential direction, are formed in a roughly trapezoidal frame shape. Each divided jig piece 71 comprises a pair of central steel wires 711, 711 that extend roughly parallel to each other along their longitudinal center, a pair of one-end inclined steel wires 712, 712 that extend roughly parallel to each other with one end connected to one end of each central steel wire 711 and inclined at approximately 60° with respect to each central steel wire 711, and a pair of other-end inclined steel wires 713, 713 that extend roughly parallel to each other with one end connected to the other end of each central steel wire 711 and inclined at approximately 60° with respect to each central steel wire 711.

[0074] The ends of each central steel wire 711, the ends of each one-end inclined steel wire 712, and the ends of each other-end inclined steel wire 713 are connected by perpendicular steel wires 714, 714 that are perpendicular to each of the respective steel wires 711, 712, and 713. In addition, the upper ends of positioning steel wires 715 that protrude downward for positioning with the locking portion 8, which will be described later, are connected to the inside of the inner one-end inclined steel wire 712 and to the inside of the inner other-end inclined steel wire 713.

[0075] Figure 21 is a plan view showing the attachment part combined with the locking part for securing the two divided jig pieces of Figure 18 to the temporary hoop reinforcement 33T for attachment, Figure 22 is a perspective view of the locking part of Figure 21, and Figure 23 is a side view of the locking part of Figure 21.

[0076] Each frame-shaped jig 7 (each divided jig piece 71) is provided with a locking portion 8 for engaging the frame-shaped jig 7 with the temporary hoop reinforcement 33T for mounting. This locking portion 8 is formed in a roughly grid shape by four reinforcing bars 811, 812, 813, and 814 that intersect with each other and extend in the in-plane direction of the temporary hoop reinforcement 33T for mounting, so that both ends of the locking portion 8 straddle the temporary hoop reinforcement 33T for mounting.

[0077] Each of the reinforcing bars 811, 812, 813, and 814 consists of two lower reinforcing bars 811 and 812 that intersect each other parallel to one another vertically and are stretched across the temporary hoop reinforcement 33T for attachment, and two upper reinforcing bars 813 and 814 that are placed on top of these lower reinforcing bars 811 and 812 and are stretched across the temporary hoop reinforcement 33T for attachment. One end of each upper reinforcing bar 813 and 814 (the upper end in Figures 21 and 22) is bent downward at approximately 90° and secured to the temporary hoop reinforcement 33T for attachment from above.

[0078] Furthermore, each side of the roughly square-shaped enclosed portion 82 (enclosed portion) surrounded by each reinforcing bar 811-814 is provided with an attachment portion 72 positioned closer to the center of the temporary hoop reinforcement 33T for attachment than each dividing jig piece 71. This attachment portion 72 is placed on the upper side of the enclosed portion 82 of each reinforcing bar 811-814 and comprises a pair of inner and outer steel wires 731, 732 that extend roughly parallel to each lower reinforcing bar 811, 812 on both the inner and outer sides of each lower reinforcing bar 811, 812, and a connecting steel wire 733 that extends roughly parallel to each upper reinforcing bar 813, 814 on the outside of each upper reinforcing bar 813, 814, with both ends connected to the inner steel wire 731.

[0079] Both ends of the outer steel wire 732 are stretched across the upper reinforcing bars 813 and 814. In this case, the attachment portion 72 is restrained by binding wire (not shown) to the lower reinforcing bars 811 and 812 and the upper reinforcing bars 813 and 814 of the locking portion 8.

[0080] Furthermore, each inner and outer steel wire member 731, 732 is provided with connecting steel wire members 734, 734 that connect both ends of the inner and outer steel wire members 731, 732 between the upper reinforcing bars 813, 814. Each connecting steel wire member 733 is provided with protruding steel wire members 735, 735 at both ends, with their base ends (outer ends) connected to each other and projecting inwards in a direction opposite to each other.

[0081] The tip of each protruding steel wire 735 is stretched across each of the upper reinforcing bars 813 and 814. Each dividing jig piece 71 is then restrained by binding wire (not shown) while placed on each of the lower reinforcing bars 811 and 812 and each of the upper reinforcing bars 813 and 814 of the locking portion 8.

[0082] Figure 24 shows a plan view of the rebar cage 3, in which the two dividing jig pieces 71, 71 from Figure 18 are each locked to the temporary hoop reinforcement 33T by the locking parts 8. Figure 25 also shows a plan view of the rebar cage 3, in which each bag-shaped object 2 is attached to each dividing jig piece 71 from Figure 24 by the cable ties 46.

[0083] As shown in Figure 25, the central steel wire 711, the inclined steel wire 712 at one end, and the inclined steel wire 713 at the other end of each dividing jig piece 71 are each attached with both ends of the bag-shaped object 2 secured by cable ties 46. In addition, the inner and outer steel wires 731, 732 and the connecting steel wire 733 of the attachment section 72 are also each attached with both ends of the bag-shaped object 2 secured by cable ties 46. In this case, the attachment points for the bag-shaped object 2 are increased by the attachment section 72, which is positioned closer to the center of the temporary hoop reinforcement 33T for attachment than each dividing jig piece 71.

[0084] Furthermore, the locking portion 8 that restrains each segmented jig piece 71 is equipped with a wire 45 that restrains both ends of each of its lower reinforcing bars 811, 812 and each of its upper reinforcing bars 813, 814 to the temporary hoop reinforcement 33T for attachment. This wire 45 is stretched between both ends of each of the lower reinforcing bars 811, 812 and each of its upper reinforcing bars 813, 814 and the temporary hoop reinforcement 33T for attachment. In addition, each segmented jig piece 71 is locked at four points by each of its lower reinforcing bars 811, 812 and each of its upper reinforcing bars 813, 814 to the temporary hoop reinforcement 33T for attachment, so as to ensure the equilibrium of each bag-shaped object 2 with respect to the temporary hoop reinforcement 33T, and is held in the in-plane direction of the temporary hoop reinforcement 33T.

[0085] Furthermore, as shown in Figure 24, the lower ends of the positioning steel wires 715 that protrude downward from the inside of the inner inclined steel wire 712 of each inclined steel wire 712, and from the inside of the inner inclined steel wire 713 of each inclined steel wire 713, contact the inner steel wires 731 of the mounting portion 72 from the outside (from above or below in Figure 24) when each dividing jig piece 71 is placed on the lower reinforcing bars 811, 812 and upper reinforcing bars 813, 814 of the locking portion 8, thereby positioning with respect to the locking portion 8.

[0086] Furthermore, the mounting portion 72 is attached to each segmented jig piece 71 via the lower reinforcing bars 811, 812 and upper reinforcing bars 813, 814 of the locking portion 8, so that it is positioned closer to the center of the temporary hoop reinforcement 33T for mounting than each segmented jig piece 71. In this case, the locking portion 8 and the mounting portion 72 are each formed in a roughly square shape, so that a tremie pipe into which ready-mix concrete is poured can be inserted with ample clearance.

[0087] Therefore, in this embodiment, the four reinforcing bars 811, 812, 813, and 814 are secured to the temporary hoop reinforcement 33T for installation, with both ends straddling it to form a roughly square shape. The ends of each bag-shaped object 2 are also attached by cable ties 46 to the attachment portion 72 of the enclosed portion 82 surrounded by the reinforcing bars 811, 812, 813, and 814, which is closer to the center of the temporary hoop reinforcement 33T than each dividing jig piece 71. This allows the static crushing phenomenon of concrete C due to the expansion action of the static crushing agent 21 to be utilized even closer to the center of the temporary hoop reinforcement 33T, and the static crushing effect can be more uniformly distributed within the plane of the temporary hoop reinforcement 33T, enabling efficient crushing and removal of the pile head excess portion 14.

[0088] Furthermore, since both ends of the bag-shaped object 2 are attached by cable ties 46 to the inner and outer steel wires 731, 732 and each connecting steel wire 733 of the attachment portion 72 on which the attachment portion 8 is formed in a roughly grid shape by four reinforcing bars 811, 812, 813, and 814 that are locked to the temporary hoop reinforcement 33T with both ends straddling it, it is possible to position the static crushing agent 21 even closer to the center of the temporary hoop reinforcement 33T. As a result, the static crushing phenomenon of concrete C due to the expansion action of the static crushing agent 21 can be utilized even closer to the center of the temporary hoop reinforcement 33T, which is very advantageous in more uniformly distributing the static crushing effect within the plane of the temporary hoop reinforcement 33T.

[0089] It should be noted that the present invention is not limited to the embodiments described above, but encompasses a variety of other modifications. For example, in the embodiments described above, a frame-shaped jig 4, 7 with a substantially hexagonal frame shape or a frame-shaped jig 6 with a substantially decagonal frame shape was used, which follows the inner circumferential surface of the temporary hoop reinforcement 33T for installation. However, a frame-shaped jig with a polygonal frame shape or a frame-shaped jig with a circular frame shape may also be used, which follows the inner circumferential surface of the temporary hoop reinforcement for installation.

[0090] Furthermore, in each of the above embodiments, the frame-shaped jigs 4, 6, and 7 were evenly divided into two divided jig pieces 41, 61, and 71 at angular positions with a 180° phase difference in the circumferential direction. However, the frame-shaped jig may be divided into three or more divided jig pieces in the circumferential direction.

[0091] Furthermore, in each of the above embodiments, the crushing plan line M at the pile head is set to the design pile top height of the cast-in-place pile A, but the crushing plan line at the pile head may be set directly above the design pile top height of the cast-in-place pile. In this case, the temporary hoop reinforcement for attachment is provided corresponding to directly above the design pile top height of the cast-in-place pile.

[0092] Furthermore, in each of the above embodiments, the surface casing 12 was withdrawn immediately after the concrete pouring was completed, and then the steel pipe 13 was withdrawn in time with the concrete curing. However, it is not always necessary to withdraw the steel pipe, and only a portion of the steel pipe may be left near the top of the pile hole.

[0093] Furthermore, in the first and second embodiments described above, each segmented jig piece 41 was locked to the temporary hoop reinforcement 33T for mounting at four points by the locking parts 421 to 424, each segmented jig piece 61 was locked to the temporary hoop reinforcement 33T for mounting at six points by the locking parts 621 to 626, and each segmented jig piece 71 was locked to the temporary hoop reinforcement 33T for mounting at four points by the reinforcing bars 811, 812, 813, and 814. However, it is sufficient if each segmented jig piece is locked to the temporary hoop reinforcement for mounting at three or more points by the locking parts.

[0094] Furthermore, in each of the embodiments described above, both ends of each bag-shaped object 2 (static crushing agent 21) were attached to the respective dividing jig pieces 41, 61, 71 and attachment parts 43, 63, 72 by cable ties 46, but each bag-shaped object may also be attached to the dividing jig pieces by wire or other wire material or fasteners such as clips. In addition, it goes without saying that attachment means other than fasteners may include tape, adhesive (sealant), hook-and-loop fasteners, magnets, etc.

[0095] Furthermore, in each of the above embodiments, the tips of each locking portion 421-424, 621-626 and one end of each upper reinforcing bar 813, 814 of the locking portion 8 are bent downward by approximately 90°, but the tips of the locking portions and one end of each upper reinforcing bar may be formed in a shape that makes it easy to lock onto the temporary hoop reinforcement for attachment from above and difficult to detach. [Explanation of symbols]

[0096] 11 Pile holes 14. Excess pile head portion 2 bags 21 Static crushing agent 3 Reinforcement cage 31 Internal main reinforcement (main reinforcement) 32 Outside main reinforcement (main reinforcement) 33 Hoop Muscles 33T Temporary hoop reinforcement for installation 4. Frame-shaped jig 41 Dividing jig pieces 421~424 Locking part 43 Mounting part Track 45 (wire material) 46 Cable ties (fastening devices, mounting means) 6. Frame-shaped jig 61 Dividing jig pieces 621~626 Locking part 63 Mounting part 7. Frame-shaped jig 71 Dividing jig pieces 72 Mounting part 8 Locking part 82. Enclosed area (the enclosed part) A Cast-in-place pile M Crushing Plan Line X Pile head processing device

Claims

1. A pile head processing device for a cast-in-place pile, which is made of concrete and is driven into a pile hole through which a reinforcing cage assembled in a cylindrical shape by multiple main reinforcements and multiple hoop reinforcements is inserted, is used to crush and remove the excess pile head portion of the cast-in-place pile by the expansion action of a static crushing agent placed on a crushing design line set at or directly above the design pile top height of the cast-in-place pile, The static crushing agent is contained individually in a plurality of permeable bag-like objects. A frame-shaped jig, which is positioned along the inner circumferential surface of the temporary hoop reinforcement for installation that is placed on the crushing plan line of the reinforcing cage corresponding to the crushing design line of the cast-in-place pile, is divided into multiple circumferential jig pieces, and each of the bag-shaped objects is attached to each of these pieces by an attachment means, A pile head processing device for cast-in-place piles, characterized in that each of the divided jig pieces to which the bag-shaped objects are attached is locked to the aforementioned temporary hoop reinforcement for attachment by a locking portion.

2. Each of the division jig pieces is provided with an additional mounting portion positioned closer to the center of the temporary hoop reinforcement for mounting than the respective division jig piece. The pile head processing device for cast-in-place piles according to claim 1, wherein the bag-shaped object is also attached to this mounting portion by the mounting means.

3. The locking portion is formed in a roughly grid shape by four reinforcing bars extending in the in-plane direction of the temporary hoop reinforcement for attachment, such that both ends of the locking portion straddle the temporary hoop reinforcement for attachment, In the portion surrounded by each of the aforementioned reinforcing bars, an additional mounting section is provided, positioned closer to the center of the temporary hoop reinforcement for attachment than each of the aforementioned dividing jig pieces. The pile head processing device for cast-in-place piles according to claim 1, wherein the bag-shaped object is also attached to this mounting portion by the mounting means.

4. The pile head processing device for cast-in-place piles according to any one of claims 1 to 3, wherein the attachment means is a fastening device for attaching the bag-shaped object by binding.

5. The pile head processing device for cast-in-place piles according to claim 4, wherein the locking portion of each divided jig piece is provided with a wire that restrains the locking portion in a state of being locked to the temporary hoop reinforcement for mounting.

6. The pile head processing device for cast-in-place piles according to claim 5, wherein each of the divided jig pieces is locked at three or more points by the locking portion to the temporary hoop reinforcement for mounting so as to ensure equilibrium of each bag-shaped object with respect to the temporary hoop reinforcement for mounting, and is held in the in-plane direction of the temporary hoop reinforcement for mounting.

7. A pile head treatment method for cast-in-place piles, which involves driving concrete piles into pile holes through which a reinforcing cage assembled in a cylindrical shape by multiple main reinforcements and multiple hoop reinforcements is inserted, wherein the excess pile head portion of a cast-in-place pile is crushed and removed by the expansion action of a static crushing agent placed on a crushing plan line set at or directly above the design pile top height of the cast-in-place pile, The static crushing agent is individually contained in multiple permeable bag-like objects. A frame-shaped jig, which is positioned along the inner circumferential surface of the temporary hoop reinforcement for installation that is placed on the crushing plan line of the reinforcing cage corresponding to the crushing design line of the cast-in-place pile, is divided into multiple circumferential jig pieces, and each of the bag-shaped objects is attached to each of these divided jig pieces using the attachment means. A pile head treatment method for cast-in-place piles, characterized in that each of the divided jig pieces to which the bag-shaped objects are attached is locked to the temporary hoop reinforcement for attachment by a locking portion.

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