Pile head insertion jig

Abstract

To prevent soil cement from adhering to an inner peripheral surface of a pile head of a precast pile.SOLUTION: A pile head insertion jig is removably inserted into a hollow portion formed in a pile head of a prefabricated pile having a cylindrical cross section, and comprises a main body portion which is inserted into the hollow portion formed in the pile head with a gap between it and an inner peripheral surface and which has a through hole that penetrates from bottom to top, and a hardening gel material which is placed in the gap between the inner peripheral surface and a main body portion, adheres to the inner peripheral surface, hardens over time, and in its hardened state peels off from the inner peripheral surface, when moved in a direction along the surface of the inner peripheral surface.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a pile head insertion jig. [Background technology]

[0002] Patent Document 1 describes a construction method for hollow foundation piles in which a root hardening agent is injected into an excavated hole, a hollow foundation pile is sunk into the excavated hole, and the base part of a structure is fixed in the hollow part of the pile head.The construction method for hollow foundation piles describes a construction method for hollow foundation piles in which a pile head filler is loaded into the head of the hollow foundation pile in advance, and after the hollow foundation pile has been sunk, the pile head filler is removed to form the hollow part of the pile head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 03-08922 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, one configuration involves inserting reinforcing bars or the like into a hollow space formed at the top of a prefabricated pile with a cylindrical cross section and pouring concrete into it, thereby transmitting the load from the superstructure to the prefabricated pile via the reinforcing bars.

[0005] However, when a pre-cast cylindrical pile is placed in a pile hole filled with soil cement using the pre-boring method, the soil cement clogs the hollow portion of the pile and adheres to the inner surface of the pile head. Therefore, after removing the soil cement that has adhered to the inner surface of the pile head, rebar must be inserted into the hollow portion formed in the pile head and concrete must be poured.

[0006] The object of the present disclosure is to prevent soil cement from adhering to the inner surface of the pile head of a precast pile. [Means for solving the problem]

[0007] The pile head insertion jig of the first embodiment is a pile head insertion jig that is removably inserted into a hollow portion formed in the pile head of a prefabricated pile that has a cylindrical cross section, and is characterized by comprising: a main body portion that is inserted into the hollow portion formed in the pile head with a gap between it and the inner surface of the pile head of the prefabricated pile and that has a through hole that penetrates from bottom to top; and a hardening gel material that is placed in the gap between the inner surface and the main body portion, adheres to the inner surface, hardens from a liquid state to a gel state over time, and peels off from the inner surface when moved in a hardened state along the inner surface.

[0008] According to the above aspect, a hardening gel material is placed in the gap between the inner surface of the pile head and the main body, which adheres to the inner surface and hardens from a liquid state to a gel state over time, and in its hardened state peels off from the inner surface when moved in a direction along the inner surface of the pile head.

[0009] Therefore, after a prefabricated pile with a pile head insertion jig with hardened hardening gel material inserted into the pile head is sunk into a pile hole containing stored soil cement, the pile head insertion jig is pulled out along the inner circumferential surface of the pile head, causing the hardening gel material that has adhered to the inner circumferential surface to peel off from the inner circumferential surface of the pile head. In this way, it is possible to prevent soil cement from adhering to the inner circumferential surface of the pile head of a prefabricated pile.

[0010] The pile head insertion jig of the second aspect is characterized in that, in the pile head insertion jig described in the first aspect, the main body portion is provided with a positioning portion that contacts the upper end surface of the prefabricated pile and determines the position in the insertion direction relative to the prefabricated pile.

[0011] According to the above aspect, the positioning portion of the main body comes into contact with the upper end surface of the precast pile, thereby determining the position of the pile head insertion jig in the insertion direction relative to the precast pile. In this way, the position of the pile head insertion jig in the insertion direction relative to the precast pile can be determined.

[0012] The pile head insertion jig of the third aspect is characterized in that, in the pile head insertion jig described in the first aspect, the main body portion is provided with a gasket that prevents the hardening gel material from leaking through the gap.

[0013] According to the above aspect, by providing the packing, leakage of the hardenable gel material from the gap can be suppressed. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to prevent soil cement from adhering to the inner surface of the pile head of a precast pile. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing a construction machine used in a construction method for a prefabricated pile into which a pile head insertion jig according to an embodiment of the present disclosure has been inserted. [Figure 2] 1A, 1B, and 1C are process diagrams showing the steps of a construction method for a prefabricated pile into which a pile head insertion jig according to an embodiment of the present disclosure has been inserted. [Figure 3] 1A, 1B, and 1C are process diagrams showing the steps of a construction method for a prefabricated pile into which a pile head insertion jig according to an embodiment of the present disclosure has been inserted. [Figure 4] FIG. 1 is a perspective view showing a pile head insertion jig according to an embodiment of the present disclosure. [Figure 5] 1A, 1B, and 1C are process diagrams showing a construction method for installing a pile head insertion jig according to an embodiment of the present disclosure. [Figure 6] 1A, 1B, and 1C are process diagrams showing a construction method for removing a pile head insertion jig according to an embodiment of the present disclosure. [Figure 7] 1A and 1B are process diagrams showing a construction method in which a pile head insertion jig according to an embodiment of the present disclosure is removed from a prefabricated pile and concrete is poured into the hollow space formed therein. DETAILED DESCRIPTION OF THE INVENTION

[0016] An example of a pile head insertion jig according to an embodiment of the present disclosure will be described with reference to Figures 1 to 7. Note that arrow H shown in each figure indicates the up-down direction, i.e., the vertical direction, arrow W shown in each figure indicates the width direction perpendicular to arrow H and also the horizontal direction, and arrow D shown in each figure indicates the depth direction perpendicular to arrows H and W and also the horizontal direction.

[0017] The pile head insertion jig according to this embodiment is used for cylindrical prefabricated piles. First, the construction machine used for constructing the prefabricated piles and the construction method for the prefabricated piles will be described, and then the pile head insertion jig, which is the main component, will be described.

[0018] (Construction machinery used to construct prefabricated piles 10) At the construction site where the precast piles 10 (see Figure 3) are installed, as shown in Figure 1, a pile driver (excavator) 20, a drilling fluid mixer (not shown), a cement milk plant 22, a generator 24, a water tank 26, and a silo 28 are installed.

[0019] The pile driver 20 includes a pile driver body 20a, a mast 20b, and a motor 20c. The pile driver body 20a is self-propelled, and a mast 20b is attached to the pile driver body 20a. A motor 20c is attached to the mast 20b so that the motor 20c can move up and down. Furthermore, a connecting machine 20d and a drill 20e are connected to the motor 20c.

[0020] A generator (not shown) is provided to supply power to the motor 20c, and the drilling drill 20e is rotated by the driving force of the motor 20c. Meanwhile, the drilling drill 20e has an internal flow path, and drilling fluid and cement milk (pile periphery fixing fluid and foot protection fluid) can be supplied to the internal flow path of the drilling drill 20e from a drilling fluid mixer or a cement milk plant 22 via a connector 20d. The drilling fluid and cement milk supplied to the internal flow path are then discharged from the tip (lower end) of the drilling drill 20e.

[0021] (Outline of construction method for prefabricated pile 10) The precast pile 10 to be constructed is a cylindrical precast concrete pile. First, an outline of the construction method for the precast pile 10 will be explained, and the construction method for the main parts will be described later.

[0022] 2(A) and 2(B), the drilling drill 20e is rotated to excavate the ground, thereby forming a pile hole 30. Specifically, the pile hole 30 is formed so as to penetrate the intermediate layer M of the ground and reach the bearing layer S.

[0023] In addition, in the root compaction liquid injection / stirring / mixing process shown in Figure 2(C), the root compaction liquid is supplied to the pile hole 30 while the root compaction liquid and the excavated soil are stirred and mixed to produce soil cement S02, which will become the root compaction portion, inside the pile hole 30.

[0024] Furthermore, in the pile periphery fixing liquid injection and stirring / mixing process shown in Figure 3(A), the pile periphery fixing liquid is supplied to the pile hole 30 while stirring and mixing the pile periphery fixing liquid and the excavated soil, and soil cement S01, which will become the pile periphery fixing portion, is generated inside the pile hole 30, while the drilling drill 20e is pulled up.

[0025] 3(A), (B), and (C), the drilling drill 20e is pulled up, and the prefabricated pile 10 is sunk into the pile hole 30 in which the soil cements S01 and S02 are stored by a crane and pile driver 20 (see FIG. 1), not shown. Then, the soil cement S01 overflows from the pile hole 30.

[0026] (Main part configuration) Next, we will explain the pile head insertion jig 50 that is inserted in advance into the pile head of the precast pile 10, and the construction method for the main part of the precast pile 10. The construction method for the main part of the precast pile 10 will be explained by dividing it into a construction method for attaching the pile head insertion jig 50 to the pile head of the precast pile 10 and a construction method for removing the pile head insertion jig 50 from the pile head of the precast pile 10.

[0027] [Pile head insertion jig 50] The pile head insertion jig 50 is detachably inserted into the hollow portion 10b (see Figure 5) formed in the pile head of the prefabricated pile 10, and as shown in Figure 4, is composed of a cylindrical paper void tube 52, steel plates 56, 58, a plurality of steel rods 62, packings 64, 66, and a hardening gel material 70 (see Figure 5(C)). The cylindrical paper void tube 52, steel plates 56, 58, a plurality of steel rods 62, and packings 64, 66 form the main body 50a of the pile head insertion jig 50.

[0028] -Paper void tube 52- As shown in Figure 4, the paper void tube 52 is cylindrical and extends in the vertical direction. When inserted into the head of the prefabricated pile 10, a gap 12 is formed between the outer surface 52a of the paper void tube 52 and the inner surface 10a of the head of the prefabricated pile 10, as shown in Figure 5(A).

[0029] -Steel plates 56, 58, steel rod 62- As shown in Fig. 4, the steel plate 56 is disposed above the paper void tube 52 and is disk-shaped with a circular through-hole 56a formed in the center. The outer diameter of the steel plate 56 is larger than the outer diameter of the paper void tube 52. Furthermore, a through-hole 56b is formed along the outer periphery of the steel plate 56. Furthermore, a through-hole 56c is formed in the steel plate 56 so as to surround the through-hole 56a of the steel plate 56.

[0030] 4, the steel plate 58 is disposed below the paper void tube 52 and is disk-shaped with a circular through-hole 58a formed in the center. The outer diameter of the steel plate 58 is larger than the outer diameter of the paper void tube 52 and smaller than the outer diameter of the steel plate 56.

[0031] 4, a plurality of steel rods 62 are provided, and are arranged at intervals along the inner peripheral surface of the paper void tube 52 so as to extend in the vertical direction. The lower ends of the steel rods 62 are attached by welding to the upper surface of the steel plate 58. A male thread is formed at the upper end portion of the steel rod 62, and the upper end portion of the steel rod 62 passes through a through-hole 56c of the steel plate 56 and protrudes above the steel plate 56.

[0032] Furthermore, by tightening a nut 90 (see Figure 5 (C)) to the part of the steel rod 62 that protrudes above the steel plate 56, the steel plate 58 is attached to the steel plate 56, and the paper void tube 52 is sandwiched between the steel plates 56 and 58.

[0033] In this configuration, with the pile head insertion jig 50 inserted into the pile head of the precast pile 10, the outer peripheral portion of the steel plate 56 is placed on the upper end surface 14 of the precast pile 10, as shown in Figure 5(C). Furthermore, the outer peripheral end surface of the steel plate 58 faces the inner peripheral surface 10a of the pile head of the precast pile 10.

[0034] Then, the bolt 92 is passed through the through hole 56b (see Figure 4) formed in the steel plate 56 and tightened into a female threaded hole (not shown) formed in the upper end surface 14 of the prefabricated pile 10, thereby attaching the pile head insertion jig 50 inserted into the pile head of the prefabricated pile 10 to the prefabricated pile 10.

[0035] In this way, the steel plate 56 comes into contact with the upper end surface 14 of the precast pile 10, and the pile head insertion jig 50 is attached to the pile head of the precast pile 10, thereby determining the position of the pile head insertion jig 50 in the insertion direction relative to the precast pile 10. The insertion direction of the pile head insertion jig 50 is the longitudinal direction of the precast pile 10. The steel plate 56 is an example of a positioning part.

[0036] -Packing 64, 66, Hardening gel material 70- As shown in Figure 4, the gasket 64 is positioned at the corner formed by the paper void tube 52 and the steel plate 56, surrounding the upper end portion of the outer surface 52a of the paper void tube 52 from the outside, and has a rectangular cross section.

[0037] The packing 66 is positioned at the corner formed by the paper void tube 52 and the steel plate 58 so as to surround the lower end portion of the outer surface 52a of the paper void tube 52 from the outside, and has a rectangular cross section.

[0038] In this configuration, as shown in Figure 5(C), the packing 64 is sandwiched between the upper end portion of the paper void tube 52 and the inner peripheral surface 10a of the pile head, and the packing 66 is sandwiched between the lower end portion of the paper void tube 52 and the inner peripheral surface 10a of the pile head. The inner peripheral surface 10a of the pile head, the packing 64, the outer peripheral surface 52a of the paper void tube 52, and the packing 66 make the gap 12 a blocking area that blocks the infiltration of fluid from the outside.

[0039] The hardening gel material 70 is disposed in the gap 12 as shown in Fig. 5(C). Here, the hardening gel material 70 is a "two-component mixed gel that adheres closely to the surface of the concrete and the surface of the steel, hardens from a liquid state to a gel state in a predetermined time after mixing, and after hardening into a gel state, peels off from the surface of the concrete and the surface of the steel when moved along the surface of the concrete and the steel. An example of the hardening gel material 70 is reactive PVOH (manufactured by Mitsubishi Chemical Corporation). In this embodiment, "peeling off from the surface of the concrete and the surface of the steel" means peeling off at least 80% of the concrete and the surface of the steel, where 100% is total peeling off from the surface of the concrete and the steel.

[0040] [Construction method for attaching pile head insertion jig 50 to prefabricated pile 10] Next, a construction method for attaching the pile head insertion jig 50 to the prefabricated pile 10 will be described. First, as shown in Figure 5(A), a steel plate 58 with a steel rod 62 attached, a paper void pipe 52, and a packing 66 are placed inside the head of the prefabricated pile 10. A jig (not shown) is used to keep these parts in place.

[0041] Furthermore, as shown in FIG. 5(B), a liquid main material and a liquid hardener are injected into the gap 12 and mixed together to form a hardenable gel material 70 that hardens into a gel state after a predetermined time has passed.

[0042] 5(C), a steel plate 56 is placed on the upper end surface of the paper void pipe 52 and the upper end surface 14 of the prefabricated pile 10. Then, a nut 90 is tightened onto the male thread formed on the steel rod 62 at the portion protruding upward from the through hole 56c (see FIG. 4) of the steel plate.

[0043] Furthermore, the bolt 92 is passed through the through hole 56b (see FIG. 4) formed in the steel plate 56 and tightened into a female threaded hole (not shown) formed in the upper end surface 14 of the prefabricated pile 10, thereby attaching the pile head insertion jig 50 to the prefabricated pile 10. Then, after a predetermined time has passed, the hardening gel material 70 hardens into a gel state while adhering closely to the inner peripheral surface 10a of the pile head.

[0044] 6(A), the precast pile 10 to which the pile head insertion jig 50 is attached is sunk into the pile hole 30 in which soil cement S01 is stored. The steel plate 56 has a through hole 56a formed therein, and the steel plate 58 has a through hole 58a formed therein. As a result, when the precast pile 10 is sunk, the soil cement S01 flows inside the pile head insertion jig 50, and the soil cement S01 provides resistance so that the pile head insertion jig 50 does not come off the precast pile 10.

[0045] [Construction method for removing the pile head insertion jig 50] Next, a construction method for removing the pile head insertion jig 50 will be described. First, as shown in Figure 6(B), the soil cement S01 is partially removed so as to expose the pile head of the precast pile 10. Next, the bolts 92 are removed, and using a construction machine (not shown), the pile head insertion jig 50 is pulled out and detached from the pile head of the precast pile 10, as shown in Figure 6(C). Specifically, the pile head insertion jig 50 is pulled out and detached from the pile head of the precast pile 10 in the direction along the inner peripheral surface 10a of the precast pile 10.

[0046] Here, the hardening gel material 70, which has hardened into a gel state while adhering to the inner peripheral surface 10a of the pile head, is a material that peels off from the surface of the concrete when moved along the surface of the concrete, thereby exposing the inner peripheral surface 10a to which the hardening gel material 70 had adhered.

[0047] Furthermore, by removing the pile head insertion jig 50, reinforcing bars 110 such as steel frames or reinforcing bars are inserted into the exposed hollow portion 10b, and concrete is poured, as shown in Figures 7(A) and 7(B). As a result, the force from the superstructure is transmitted to the precast pile 10 via the reinforcing bars 110 and the poured concrete.

[0048] (summary) As described above, the pile head insertion jig 50 is attached to the pile head of the precast pile 10, and after the precast pile 10 is sunk, the pile head insertion jig 50 is detached from the precast pile 10. The hardening gel material 70, which has hardened into a gel state while adhering to the inner peripheral surface 10a of the pile head, is a component that peels off from the concrete surface when moved along the concrete surface. Therefore, the inner peripheral surface 10a to which the hardening gel material 70 was adhered is exposed to the outside. In this way, the adhesion of the soil cement S01 to the inner peripheral surface 10a of the pile head of the precast pile 10 can be suppressed. In other words, the effort required to remove the soil cement S01 from the inner peripheral surface 10a of the pile head of the precast pile 10 can be reduced.

[0049] Furthermore, a steel plate 56 is provided in the main body 50a of the pile head insertion jig 50, which comes into contact with the upper end surface 14 of the prefabricated pile 10 to determine its position in the insertion direction relative to the prefabricated pile 10. In this way, the position of the pile head insertion jig 50 in the insertion direction relative to the prefabricated pile 10 can be determined.

[0050] Furthermore, the main body 50a of the pile head insertion jig 50 is provided with a steel plate 56 that comes into contact with the upper end surface 14 of the prefabricated pile 10 to determine its position in the insertion direction relative to the prefabricated pile 10. In this way, the position of the main body 50a in the insertion direction can be determined.

[0051] Furthermore, the main body 50a of the pile head insertion jig 50 is provided with packings 64, 66 that prevent the hardening gel material 70 from leaking from the gap 12. This makes it possible to prevent the hardening gel material 70 from leaking from the gap 12 before hardening.

[0052] Furthermore, the main body 50a of the pile head insertion jig 50 is provided with packings 64, 66 that hold the hardening gel material 70 in place from above and below. As a result, the packings 64, 66 can protect the hardening gel material 70 when the prefabricated pile 10 is sunk into the pile hole 30 in which the soil cements S01, S02 are stored.

[0053] Although the present disclosure has been described in detail with respect to a specific embodiment, it will be apparent to those skilled in the art that the present disclosure is not limited to such an embodiment and that various other embodiments are possible within the scope of the present disclosure. For example, in the above embodiment, the precast pile 10 is a cylindrical precast concrete pile, but it may also be a cylindrical steel pipe pile.

[0054] Furthermore, although not specifically explained in the above embodiment, any hardening gel material may be used for the hardening gel material 70, as long as it is a two-component mixed gel that adheres closely to the surface of the concrete and the surface of the steel material, hardens from a liquid state to a gel state within a predetermined time after mixing, and, after hardening into a gel state, peels off from the surface of the concrete and the surface of the steel material when moved in a direction along the surface of the concrete and the steel material.

[0055] Furthermore, in the above embodiment, the reinforcing bar 110 is inserted into the hollow portion 10b, but it is not necessary to insert the reinforcing bar 110.

[0056] In the above embodiment, the paper void tube 52 is used as the cylindrical member constituting the pile head insertion jig 50, but other members may also be used. [Explanation of symbols]

[0057] 10 Prefabricated piles 10a Inner surface 10b Hollow part 12 Gap 14 Upper end surface 50 Pile head insertion jig 50a Main body 56 Steel plate (example of positioning part) 56a Through hole 58a Through hole 64 Gasket 66 Gasket 70 Hardening gel material S01 Soil cement

Claims

1. A pile head insertion jig that is detachably inserted into a hollow portion formed in the pile head of a prefabricated pile having a cylindrical cross section, A main body portion having a through hole formed therein and penetrating from below to above, the main body portion being inserted into a hollow portion formed in the head portion of the prefabricated pile with a gap between the main body portion and the inner peripheral surface of the head portion of the prefabricated pile; a hardening gel material that is disposed in a gap between the inner circumferential surface and the main body, that adheres closely to the inner circumferential surface, that hardens from a liquid state into a gel state over time, and that peels off from the inner circumferential surface when moved in a surface-aligning direction relative to the inner circumferential surface in the hardened state; A pile head insertion jig equipped with:

2. The main body is provided with a positioning portion that contacts the upper end surface of the prefabricated pile to determine the position of the prefabricated pile in the insertion direction. The pile head insertion jig according to claim 1.

3. The main body is provided with a packing that prevents the hardening gel material from leaking through the gap. The pile head insertion jig according to claim 1.

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