JP2024077276A - Suspension tool and steel pipe pile erecting method using the same - Google Patents

Abstract

To provide a suspension tool for efficiently installing a steel pipe pile, and a steel pipe pile erecting method using the same.SOLUTION: A suspension tool 10 is detachably attached to a pile structure 20 having a cylindrical screw-type mechanical joint 23 provided at an axial end. The suspension tool 10 comprises: a circular-arc attachment 11 along the outer periphery of the mechanical joint 23; and a suspension 15 engaged with a shackle. A fixing hole 11h for inserting a bolt B1 in alignment with a screw hole 25 formed in the mechanical joint 23 is formed in the attachment 11. By repeating suspension of the pile structure 20 using the suspension tool 10 and connection to the pile structure 20 disposed below, a steel pipe pile formed by a plurality of pile structures 20 is erected in the ground.SELECTED DRAWING: Figure 2

Description

This disclosure relates to a lifting jig that can be detachably attached to a pile structure equipped with a screw-type mechanical joint, and a method for erecting steel pipe piles using the same.

Conventionally, when the ground of a building is weak, a cylindrical steel pile (steel pipe pile) may be driven into the ground (see, for example, Patent Documents 1 and 2). Patent Document 1 describes a method for inserting a steel pipe pile, in which a steel pipe pile is pressed into a borehole. In this case, a borehole is formed in the ground by rotating the drilling bit while applying a vibratory force. Then, after stirring the soil and cement milk produced by the excavation of the ground, the steel pipe pile is pressed into the borehole while applying a vibratory force and a rotating force. Patent Document 2 also shows an upper pile and a lower pile that constitute a steel pipe pile. A wire with a ring attached via a shackle to a hole in a hanging bracket welded to the upper pile is lifted by a crane. Then, the lower end of the upper pile is aligned with the upper end of the lower pile, and the male threaded portion provided at the lower end of the upper pile is screwed into the female threaded portion provided at the upper end of the lower pile to connect the upper pile and the lower pile. After that, the hanging bracket of the upper pile is cut by gas cutting.

There is also a technique for forming a steel pipe pile by connecting multiple pile structures in the axial direction. In this case, a pile structure is used in which a screw-type mechanical joint is provided at the axial end of the pile structure (see, for example, Non-Patent Document 1). In Non-Patent Document 1, a steel pipe pile is formed which is connected by screwing together a Hi-Mecha Screw (registered trademark) of a PIN joint provided at the lower end of the upper pile and a Hi-Mecha Screw of a BOX joint provided at the upper end of the lower pile. In this case, the Hi-Mecha Screw at the upper end of the lower pile has multiple holes for inserting a reverse rotation prevention pin.

JP 2011-74726 A Japanese Patent Application Laid-Open No. 8-158359

JFE Steel Corporation, "JFE Steel Pipe Pile", [online], [searched on November 22, 2022], Internet <URL: https://www.jfe-steel.co.jp/products/katakou/catalog/d1j-502.pdf>

In the steel pipe pile described in Patent Document 2, a hanging bracket is welded to the outer periphery of the mechanical joint of the upper pile. Then, after the upper pile and the lower pile are connected, the hanging bracket is removed from the upper pile by gas cutting. At this time, if the steel pipe pile is thermally deformed by welding or melting with a burner or the like, it becomes difficult to connect the upper pile and the lower pile. Furthermore, in a site where the use of fire is restricted, the bracket cannot be cut off.
Furthermore, steel pipe piles generally need to be erected before the soil cement in the pile hole hardens. Here, if the number of extensions to the pile structure that constitutes the steel pipe pile is large due to the low head, the cutting of the hanging brackets and the like will also be increased, which will take a lot of work time.

The lifting jig that solves the above problem is a lifting jig that can be detachably attached to a pile structure having a cylindrical screw-type mechanical joint at the axial end, and is equipped with an arc-shaped mounting part that follows the outer periphery of the mechanical joint and a hanging part that engages with a hanging member, and the mounting part has a fixing hole that aligns with a hole formed in the mechanical joint and allows a bolt to be inserted through it.

Furthermore, a steel pipe pile installation method that solves the above problem involves using a lifting jig to lift a pile structure with a cylindrical screw-type mechanical joint at its axial end, and then erecting the steel pipe pile in the ground while connecting it axially to other pile structures. The mechanical joint has multiple holes formed therein, and the lifting jig has an arc-shaped mounting section that follows the outer periphery of the mechanical joint with the fixing holes formed therein, and a hanging section that engages with a hanging member. The lifting jig is attached to the pile structure by inserting a bolt while aligning the hole and the fixing hole.

According to the present invention, steel pipe piles can be installed efficiently.

FIG. 2 is a perspective view illustrating a configuration of the hanging jig according to the embodiment. FIG. 2 is a perspective view of the lifting jig of the embodiment attached to a pile structure. FIG. 2 is a front view showing a state in which the pile structure is lifted using the lifting jig of the embodiment. FIG. 1 is a top view of a steel pipe pile that has been lifted using a lifting jig in an embodiment and then lowered. FIG. 1 is a side view showing a steel pipe pile that has been lifted using the lifting jig in the embodiment and then lowered.

Hereinafter, an embodiment of a lifting jig and a steel pipe pile installation method using the same will be described with reference to Figures 1 to 5. In this embodiment, a steel pipe pile consisting of multiple pile structures is erected in the ground by repeatedly joining a pile structure lowered into a pile hole to another pile structure placed above it.
FIG. 1 is a perspective view of a lifting jig 10 used to lift a pile structure 20, and FIG. 2 is a perspective view of the lifting jig 10 attached to the pile structure 20. As shown in FIG.

(Configuration of the pile structure 20)
First, the configuration of a pile structure 20 to which the lifting jig 10 is attached will be described with reference to FIG.
The pile structure 20 includes a cylindrical main body tube 21 and screw-type mechanical joints 23, 26 arranged in the axial direction (up-down direction) of the main body tube 21. Specifically, the mechanical joint 23 having an internal thread is fixed integrally to the upper end of the pile structure 20 by welding. A plurality of screw holes 25 are formed in the mechanical joint 23 in a row at equal intervals in the circumferential direction. These screw holes 25 function as pin insertion holes into which reverse rotation prevention pins are inserted and bolt insertion holes. Here, the bolt insertion hole is aligned with the pin insertion hole and is a hole through which the bolt B1 for attaching the lifting jig 10 is inserted. In this embodiment, two adjacent screw holes 25 and two screw holes 25 facing the screw holes 25 (a total of four) are used as bolt insertion holes.

A mechanical joint 26 having a male thread is fixed integrally to the lower end of the pile structure 20 by welding. The lower end of the mechanical joint 26 has a plurality of spaced semicircular arc-shaped cutouts 27. The cutouts 27 are formed so as to align with the screw holes 25 as pin insertion holes of the mechanical joint 23 of the pile structure 20 to be connected when connecting to another pile structure 20. After the cutouts 27 and the pin insertion holes of the screw holes 25 are aligned, a reverse rotation prevention pin is inserted to suppress reverse rotation (rotation in the direction that loosens the screw) of the screwed connection between the upper pile structure 20 (upper pile) and the lower pile structure 20 (lower pile). Note that high-mechanical screws manufactured by JEF Steel Co., Ltd. can be used as the screw-type mechanical joints 23 and 26.

(Configuration of the hanging jig 10)
Next, the configuration of the hanging jig 10 will be described with reference to FIG.
The hanging jig 10 comprises an attachment portion 11 , a horizontal plate portion 12 and a hanging portion 15 .
The mounting portion 11 is configured with a plate member having an inner surface in an arc shape that fits along the outer periphery of the pile structure 20 to be mounted. Two spaced apart fixing holes 11h are formed in the mounting portion 11. In this embodiment, each fixing hole 11h is provided so as to align with a bolt insertion hole of a screw hole 25 formed in the pile structure 20.

The horizontal plate portion 12 is a plate-like member whose long side has an arc shape that fits along the underside of the mounting portion 11. This horizontal plate portion 12 is positioned at a right angle to the mounting portion 11 so as to extend in the circumferential direction of the pile structure 20. Specifically, the horizontal plate portion 12 is fixed to the mounting portion 11 by welding the arc-shaped portion to the lower end of the mounting portion 11.

The hanging part 15 is fixed by welding to the center of the horizontal plate part 12. This hanging part 15 is composed of a plate-shaped member with a semicircular upper part. The hanging part 15 is arranged so that it is radially outward from the mounting part 11. Furthermore, a through hole 15h is formed in the center of the hanging part 15.

(Method of installing steel pipe piles)
Next, a method of erecting piles while connecting a plurality of pile structures 20 using the above-mentioned lifting jig 10 will be described.

First, a pile hole is formed in which the steel pipe pile is to be buried, and then the formed pile hole is filled with soil cement.
As shown in Fig. 4, a positioning frame 40 is placed around the upper end of the pile hole H1. The frame 40 is placed according to the size and position of the steel pipe pile to be buried.

Next, as shown in FIG. 2, the lifting jigs 10 are placed at opposing positions on the pile structure 20, and the two lifting jigs 10 are attached to the first (lowest) pile structure 20. Specifically, the threaded hole 25, which serves as the bolt insertion hole of the pile structure 20, is aligned with the fixing hole 11h of the lifting jig 10, and then the bolt B1 is inserted. In this case, a hexagon socket bolt having a portion that screws into the threaded hole 25 of the pile structure 20 is used as the bolt B1. The lifting jig 10 is then attached to the pile structure 20 by tightening the bolt B1.

Next, as shown in FIG. 3, the pile structure 20 to which the lifting jig 10 is attached is engaged with a lifting member. A shackle 50 and a lifting balance 55 are used as the lifting member. Specifically, the bolt of the shackle 50 is inserted into the through hole 15h of the lifting portion 15 of the lifting jig 10. Then, the pile structure 20 is lifted by a lifting device using the lifting member (the shackle 50 via the lifting balance 55).

The lifted pile structure 20 is inserted into the pile hole H1 and then lowered into the pile hole H1. Then, the upper part of the preceding pile structure 20 (lower pile) is exposed from the pile hole H1. In this case, the lifting jig 10 attached to the pile structure 20 is placed on the frame 40.

Then, the following pile structure 20 (upper pile) is lifted in the same manner using the lifting jig 10. Then, the mechanical joint 26 at the lower end of the pile structure 20 (upper pile) is aligned with the mechanical joint 23 at the upper end of the pile structure 20 (lower pile) to which the lifting jig 10 placed on the frame 40 is attached. Then, the upper pile is rotated to screw the male thread of the mechanical joint 26 of the upper pile into the female thread of the mechanical joint 23 of the lower pile. Then, a reverse rotation prevention pin is inserted at a position where the notch 27 and the pin insertion hole of the screw hole 25 are aligned. As a result, the upper pile (pile structure 20) and the lower pile (pile structure 20) are combined. Then, the bolt B1 of the lower pile (pile structure 20) is removed, and the lifting jig 10 is removed from the lower pile (pile structure 20). Thereafter, the upper pile (pile structure 20) lifted by the lifting jig 10 is lowered into the pile hole H1 by the lifting device. As a result, the lower pile (pile structure 20) connected to the upper pile is also lowered into the pile hole H1.
By repeating the above operations, a steel pipe pile consisting of multiple pile structures 20 is formed as it descends into the ground while connecting the upper piles to the lower piles.

As shown in Figures 4 and 5, before removing the lifting jig 10 from the pile structure 20 that is the top of the steel pipe pile, the position of the steel pipe pile is adjusted. Specifically, with the top of the top pile structure 20 exposed from the pile hole, four jacks 70 are placed between the lifting jig 10 attached to the pile structure 20 and the frame 40. For example, journal jacks are used as the jacks 70. The jacks 70 are placed on the frame 40 and are placed on both ends of the horizontal plate portion 12 of the lifting jig 10. The height of the horizontal plate portion 12 relative to the frame 40 is adjusted by the jacks 70, thereby adjusting the inclination of the steel pipe pile relative to the pile hole H1. After the inclination adjustment of the steel pipe pile is completed, the lifting jig 10 is removed from the top pile structure 20.

(Action)
The fixing hole 11h of the mounting portion 11 of the lifting jig 10 is aligned with the screw hole 25 of the mechanical joint provided in the pile structure 20, and the bolt B1 is inserted therethrough, thereby fixing the lifting jig 10 to the pile structure 20. Then, the bolt B1 is removed, whereby the lifting jig 10 is detached from the pile structure 20.

According to this embodiment, the following effects can be obtained.
(1) The lifting jig 10 of this embodiment includes an attachment portion 11 having a fixing hole 11h and extending along the outer periphery of the pile structure 20, and a hanging portion 15 having a through hole 15h. The fixing hole 11h of the attachment portion 11 is aligned with the screw hole 25 of the mechanical joint provided on the pile structure 20, and the bolt B1 is inserted to attach the lifting jig 10 to the pile structure 20. This allows the pile structure 20 to be lifted by attaching a shackle 50 or the like to the through hole 15h of the hanging portion 15. In addition, the lifting jig 10 can be removed by removing the bolt B1, so that the pile structure 20 is not thermally deformed during removal, and the lifting jig 10 can be attached and removed in a short time. Furthermore, the lifting jig 10 can be reused.

(2) The lifting jig 10 of this embodiment includes a horizontal plate portion 12 that is connected to the mounting portion 11. By rotating the upper pile while this horizontal plate portion 12 is placed on the frame 40, the upper pile and the lower pile can be efficiently integrated. Furthermore, the inclination of the steel pipe pile constituted by the pile structure 20 relative to the pile hole H1 can be adjusted by the jacks 70 arranged between both ends of the horizontal plate portion 12 and the frame 40.

(3) In this embodiment, the hanging jig 10 welds the hanging portion 15 to the center of the side plate portion 12. This reinforces the plate-shaped side plate portion 12, thereby suppressing twisting of the side plate portion 12.

(4) In this embodiment, a hexagon socket bolt is used as the bolt B1 that is inserted by aligning the fixing hole 11h of the lifting jig 10 with the screw hole 25 of the pile structure 20. This eliminates the need to grip and rotate the outer periphery of the bolt B1 to tighten the bolt, and allows the fixing hole 11h to be located near the horizontal plate portion 12. Therefore, the height of the lifting jig 10 can be reduced.

(5) In this embodiment, multiple screw holes 25 are formed in the mechanical joint 23 provided at the upper end of the pile structure 20. These screw holes 25 function as pin insertion holes and bolt insertion holes into which the reverse rotation prevention pins are inserted. Therefore, the bolt insertion holes and the pin insertion holes can be formed at the same time.

This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.
In the above embodiment, the threaded holes 25 used as the pin insertion holes and the bolt insertion holes are provided at equal intervals in the mechanical joint 23 of the pile structure 20. The intervals and sizes of the threaded holes 25 do not have to be the same. For example, pin insertion holes for inserting reverse rotation prevention pins may be provided at equal intervals, and bolt insertion holes may be provided between the pin insertion holes. Furthermore, the pin insertion holes and the bolt insertion holes may be provided in different sizes.

In the above embodiment, the hanging portion 15 of the hanging jig 10 is fixed by welding to the center of the horizontal plate portion 12 on top of the horizontal plate portion 12. The hanging portion 15 is not limited to being fixed to the horizontal plate portion 12, but may be fixed to the side surface of the mounting portion 11. In this case, the horizontal plate portion 12 may be omitted. In addition, the shape of the hanging portion 15 is not limited to an arc shape at the top, and may be other shapes, such as a rectangular shape with rounded corners. Furthermore, the number of fixing holes 11h provided in the mounting portion 11 is not limited to two, and may be provided according to the load of the steel pipe pile.
The hanging portion 15 is provided to extend radially outward from the mounting portion 11 in order to reinforce the horizontal plate portion 12. In order to reinforce the horizontal plate portion 12, a reinforcing member other than the hanging portion 15 (for example, a reinforcing member extending in a direction perpendicular to the hanging portion 15) may be further provided on the horizontal plate portion 12.
Furthermore, although the horizontal plate portion 12 is provided so as to be connected to the lower end portion of the mounting portion 11, it may be provided so as to be connected to the upper end portion or the center of the mounting portion 11. Furthermore, although the horizontal plate portion 12 has an inner arc shape and an outer shape with right-angled corners, the outer corners may be cut out obliquely or may have an outer arc shape.

In the above embodiment, a hexagon socket head bolt is used as the bolt B1 for attaching the lifting jig 10 to the pile structure 20. The bolt for attaching the lifting jig 10 to the pile structure 20 is not limited to this, and a normal bolt may be used. When a normal bolt is used, it is preferable to widen the distance between the fixing hole 11h of the attachment portion 11 and the horizontal plate portion 12 in terms of the operability of a wrench for rotating the bolt.
Moreover, when connecting the upper pile to the lower pile, the lifting jig 10 attached to the lower pile is placed on the frame 40. Even when connecting the upper pile to the lower pile, the inclination of the lower pile may be adjusted using the jack 70 before being connected to the upper pile.

Next, the technical ideas that can be understood from the above embodiment and other examples will be described below.
(a) A hanging jig as described in claim 3, characterized in that the hanging portion is fixed by welding at the center of the horizontal plate portion in a state where it is arranged so as to protrude radially outward from the mounting portion.

B1...bolt, H1...pile hole, 10...suspension jig, 11...mounting portion, 11h...fixing hole, 12...horizontal plate portion, 15...suspension portion, 15h...through hole, 20...pile structure, 21...main pipe, 23, 26...mechanical joint, 25...screw hole, 27...notch portion, 40...frame, 50...shackle, 55...suspension balance, 70...jack.

Claims (4)

A lifting jig that can be detachably attached to a pile structure having a cylindrical screw-type mechanical joint at an axial end,
An arc-shaped mounting portion that fits along an outer periphery of the mechanical joint;
A hanging portion that engages with the hanging member,
A lifting jig, characterized in that the mounting portion is formed with a fixing hole for inserting a bolt in alignment with a hole formed in the mechanical joint. The lifting jig according to claim 1, characterized in that the fixing hole is formed alongside a hole into which a reverse rotation prevention pin formed on the outer periphery of the mechanical joint is inserted. The lifting jig according to claim 1 or 2, further comprising a horizontal plate portion connected to one end of the mounting portion and protruding radially outward from the mounting portion. A steel pipe pile installation method in which a pile structure having a cylindrical screw-type mechanical joint at an axial end is lifted using a lifting jig and connected to another pile structure in the axial direction while erecting a steel pipe pile in the ground,
The mechanical joint has a plurality of holes formed therein,
The hanging jig includes an arc-shaped mounting portion that is aligned along an outer periphery of the mechanical joint in which a fixing hole is formed, and a hanging portion that engages with a hanging member,
A steel pipe pile installation method, characterized in that the lifting jig is attached to the pile structure by inserting a bolt while aligning the hole with the fixing hole.

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