JP7527567B2 - Core material for small diameter cast-in-place piles - Google Patents

Description

The present invention relates to a core material for small-diameter cast-in-place piles that is inserted into pile holes 50 filled with a hardening material such as mortar, and in particular to a core material for small-diameter cast-in-place piles that has both a spacing function for the pile holes 50 and a bearing function for the hardening material.

A ground reinforcement method (e.g., root pile method, EP root pile method) is known in which a core material is inserted into a pile hole 50 filled with a hardening material such as mortar to construct a small-diameter cast-in-place pile, and multiple small-diameter cast-in-place piles are used as tension reinforcement or compression reinforcement for the ground or slopes (Patent Documents 1 and 2).

A core material 60 used in a small-diameter cast-in-place pile will be described with reference to FIG.
The conventional core material 60 comprises a bar material 20 such as a different diameter steel bar to be inserted into a pile hole 50, spacers 70 attached to the bar material 20 at appropriate intervals, and a flange material 80 attached to the bar material 20 at appropriate intervals and screwed thereto.
The bar 20 is formed with an external thread along its entire length.
The spacer 70 comprises a cylindrical portion 71 that can be screwed to the bar 20, and a plurality of vanes 72 provided in an arrow feather shape along the axial direction of the outer peripheral surface of the cylindrical portion 71. The vanes 72 function to maintain the distance between the bar 20 and the pile hole 50.
The cast flange material 80 has a cylindrical portion 81 that can be screwed onto the bar material 20, and an enlarged diameter portion 82 that protrudes radially from the outer circumferential surface of the cylindrical portion 1.
The spacer 70 and the flange member 80 have female threads formed in their centers, and the mounting position can be adjusted along the axial direction of the bar member 20 by rotating them.

Japanese Unexamined Patent Publication No. 55-136322 Publication No. 61-6531 Japanese Patent Application Publication No. 58-17931

The above-mentioned core material for small-diameter cast-in-place piles has the following inherent problems.
<1> The core material 60 has a large number of components, and the cost of the core material 60 is high.
<2> Since both the spacer 70 and the flange material 80 are screwed in, the spacer 70 and the flange material 80 are attached by screwing them into the end of the bar 20 up to a predetermined position to produce the core material 60. However, it takes a lot of time and effort to produce the core material 60, and the production efficiency of the core material 60 is low.
In particular, in order to restrict the free rotation of the flange material 80, a wedge must be driven between the bar material 20 and the flange material 80 to fix it in place, which takes extra time to install the flange material 80.
<3> In order to improve corrosion resistance, it is desirable to subject the outer surface of the bar 20 to an anti-rust treatment such as zinc plating.
However, since the outer peripheral surface of the bar 20 is not a smooth surface but has a screw groove formed thereon, plating dripping is likely to occur.
If plating drips from the bar 20, the flange 80 and other parts cannot be screwed in, making it impossible to manufacture the core 60.

The present invention was made in consideration of the above points, and its purpose is to provide a core material for small-diameter cast-in-place piles that reduces the number of components of the core material and can be attached to rod material that has been treated with an anti-rust treatment.

The present invention relates to a core material for small-diameter cast-in-place piles, which is used by inserting it into a pile hole and which comprises a rod material which adheres to the consolidated material filled in the pile hole , the core material comprising: a rod material having at least one of either a concave or convex element on its outer peripheral surface; and a composite flange material which can be attached to the outer peripheral surface of the rod material by clamping it from the side of the rod material and which has both a flange function and a spacing function. The composite flange material comprises a pair of split tubes which can be embraced by the rod material, a flange material protruding circumferentially on the outer peripheral surface of each of the split tubes, and a plurality of spacing retaining portions which intersect with the flange material and protrude radially along the axial direction on the outer peripheral surface of the split tubes, and the composite flange material is integrally molded from resin so that the intersections between the flange material and the spacing retaining portions are integrated .
In another aspect of the present invention, the inner circumferential surfaces of the pair of split cylinders are formed into a shape capable of fitting into a recess or protrusion on the outer circumferential surface of the bar material.
In another form of the present invention, a protrusion may be formed on the inner surfaces of the pair of split tubes, and the protrusion may abut against a flat side surface formed along the axial direction on the outer surface of the rod material to restrict free rotation of the composite rib material relative to the rod material.
In another embodiment of the present invention, the flange member is formed of a pair of split flanges protruding in the circumferential direction from the outer circumferential surface of each of the split cylinders .
In another embodiment of the present invention, the pair of split cylinders have a pair of flanges at both axial end edges, and a hinge is formed between one of the flanges.
In another embodiment of the present invention, the maximum projection dimension of the flange is formed to be the same as the maximum projection dimension of the spacer retaining portion.
In another embodiment of the present invention, the composite flange member further comprises a closing means for closing the opening of the split tube.
The closing means of the composite flange may be either a binding belt or a locking structure of a locking claw and locking hole provided on the other pair of flanges formed on the other of the split tubes, or a combination of both.

The present invention has at least one of the following advantages.
<1> In the present invention, a single sandwich-type composite flange material can be used in place of the conventional spacer and flange material.
Therefore, in the present invention, the number of components of the core material can be reduced, and the production process of the core material can be made more efficient.
<2> Since the composite flange material is a clamping type, it can be attached to any position on the bar material without screwing it in by simply clamping and closing the opening of the composite flange material from the side of the bar material.
<3> Since the composite flange material is not a screw-in type, it can be attached to any position on the bar even if plating drips from the surface of the bar that has been treated with an anti-rust treatment such as zinc plating.
<4> By adjusting the maximum protrusion dimension of the flange to the maximum protrusion dimension of the spacing retaining portion, the flange can be given a spacing retaining function.
<5> By bringing the protrusions formed on the inner peripheral surfaces of the pair of split cylinders into contact with the flat outer peripheral surface of the bar, the free rotation of the composite flange material relative to the bar can be restricted.
<6> By integrating the intersection portion of the flange material and the spacing retaining portion, the strength of the flange material and the spacing retaining portion can be increased.

An explanatory diagram of the core material for small-diameter cast-in-place piles according to the present invention. Overall perspective view of composite tsuba material Overall perspective view of the expanded composite tsuba material An explanatory diagram of the method of manufacturing the core material. (A) is an explanatory diagram of the mounting of the expanded composite tsuba material onto the bar material, and (B) is an explanatory diagram of the core material with the composite tsuba material fixed to the bar material. An explanatory diagram of the expanded composite tsuba material Conventional core material for small-diameter cast-in-place piles

The present invention will be described in detail below with reference to the drawings.

<1> Core material for small-diameter cast-in-place piles Referring to Figures 1 to 5, the core material for small-diameter cast-in-place piles (hereinafter referred to as the "core material") 10 comprises a bar material 20 such as a different diameter steel bar to be inserted into a pile hole 50, and a composite flange material 30 which can be attached to the outer peripheral surface of the bar material 20 by clamping it from the side.

<2> Bar material The bar material 20 may be, for example, a steel bar such as a deformed reinforcing bar having knots and ribs, a deformed steel bar, or a steel pipe having steps or depressions on the outer circumferential surface, such as a stepped steel pipe, an oblique stepped steel pipe, or a dimpled steel pipe. Any bar material 20 may be used as long as it has at least one of the elements of a recess or a projection on the outer circumferential surface.
In this example, a form will be described in which the bar material 20 is a threaded steel bar having a helical male thread 21 formed on the outer circumferential surface.

The bar 20 may be made of steel material whose surface has not been treated for rust prevention, or may be made of steel material whose outer circumferential surface has been treated for rust prevention.
As the rust-preventive material, a known plating material such as zinc plating can be used.
In the present invention, since the composite flange material 30 is of a non-screw type, the composite flange material 30 can be attached even if plating drips are present on the outer peripheral surface of the bar material 20.

<3> Composite flange material In describing the composite flange material 30 , the “axial direction” refers to a direction parallel to the axial direction of the bar material 20 , and the “circumferential direction” refers to a direction parallel to the circumferential direction of the bar material 20 .

Explaining with reference to Figures 2 and 3, the composite flange material 30 is a composite material having both a flange function and a space-retaining function, and is integrally molded from resin or the like.
The composite flange material 30 comprises a pair of split tubes 31, 31 which can be fitted around the rod material 20 and embraced thereon, a flange material 32 consisting of split flanges 23a, 32a which protrude circumferentially from the central outer circumferential surface of the split tubes 31, 31, a plurality of spacing retaining portions 33 which protrude axially from the outer circumferential surface of the split tubes 31, 31, and closing means for closing the openings of the split tubes 31, 31.

<3.1> Split Cylinder The split cylinders 31, 31 are a pair of half cylinders formed by dividing a cylinder capable of being fitted onto the outer circumferential surface of the bar 20 in the axial direction.

<3.1.1> Flanges Each split tube 31, 31 has flanges 31a, 31b bent outward at both axial ends, so that when the split tubes 31, 31 are closed, a pair of opposing flanges 31a, 31a and a pair of opposing flanges 31b, 31b can come into contact with each other.

<3.1.2> Hinge In this example, the flanges 31b, 31b on one side are integrally connected via a hinge 31c, and the split cylinders 31, 31 can be opened and closed around the hinge 31c.

The pair of split tubes 31, 31 may be configured as separate and independent tubes 31, 31 without providing the hinge 31c.

<3.1.3> Inner Surface of Split Cylinder The inner surface of the split cylinders 31 , 31 has a shape that can fit into the shape of the concave or convex portion on the outer surface of the bar 20 .
The reason why the inner surface of the split tubes 31, 31 is shaped to match the uneven shape of the outer surface of the bar 20 is so that when the composite flange material 30 is attached to the bar 20, it cannot slide in the axial direction of the bar 20.
In this example, a helical female thread 31d is formed on the inner peripheral surface of the split tubes 31, 31 in accordance with the outer peripheral surface of the bar material 20 on which the helical male thread 21 is formed.

Furthermore, as shown in FIG. 5, protrusions 31h, 31h that protrude along the axial direction are formed on part of the female thread 31d on the inner peripheral surface of the split tubes 31, 31, and these protrusions 31h, 31h are abutted against the flat side surface 22 formed along the axial direction on the outer peripheral surface of the bar material 20 shown in FIG. 1, thereby clamping them together, thereby preventing the composite flange material 30 from freely rotating relative to the bar material 20.

<3.2> Flange Material A split flange 32a, 32a is protruded from the central outer circumferential surface of each split cylinder 31, 31, and a continuous annular flange material 32 is formed by the split flanges 32a, 32a when the split cylinders 31, 31 are closed.
Along the circumferential direction, the jaw members 32 are projections which function to increase adhesion to the consolidation material 51 .

<3.2.1> Shape of the flange material In this example, the three-dimensional shape of the flange material 32 is a hexagonal nut, but there are no particular restrictions on the three-dimensional shape of the flange material 32. In addition to the hexagonal nut shape, the three-dimensional shape of the flange material 32 may be a disk shape or a polygon other than a hexagon.
The protruding dimension and axial thickness of the flange member 32 are appropriately selected depending on the purpose, etc.

The protruding dimension of the flange material 32 is smaller than the protruding dimension of the spacing retaining portion 33 (or the diameter of the pile hole 50). This is to prevent the flange material 32 from blocking the space of the pile hole 50.

<3.3> Spacing retaining portions On the outer circumferential surface of the split cylinders 31, 31, a plurality of spacing retaining portions 33 are provided so as to protrude radially along the axial direction.
The multiple spacing retaining portions 33 are plate-like protrusions that provide the composite flange material 30 with a spacing retaining function (centering function).
As shown in FIGS. 1 and 2, the spacing portion 33 has a semicircular shape so as to facilitate movement within the pile hole 50.
Furthermore, by adjusting the maximum protruding dimension of each of the flanges 31a, 31b to the same dimension as the maximum protruding dimension of the semicircular spacing retaining portion 33, it is possible to impart a spacing retaining function to each of the flanges 31a, 31b.

<3.4> Dimensional Relationship Between the Flange Material and the Spacing Retaining Portion The maximum protruding dimension of the spacing retaining portion 33 having the spacing retaining function of the bar 20 and each of the flanges 31 a, 31 b is approximately the same diameter as the pile hole 50.
The spacing portion 33 has a larger diameter than the flange member 32 .

<3.5> Reason for integrating the intersection portion of the flange material and the spacing maintaining portion The intersection portion of the flange material 32 protruding from the outer circumferential surface of each split cylinder 31, 31 and the spacing maintaining portion 33 is integrated.
The intersection portion between the flange material 32 and the spacing portion 33 is integrated because they reinforce each other, increasing the strength of the flange material 32 and the spacing portion 33.
For example, it is possible to separate and intersect the flange material 32 and the spacing retaining portion 33 without integrating them, but if the flange material 32 and the spacing retaining portion 33 are formed separately, the reinforcing effect between the flange material 32 and the spacing retaining portion 33 cannot be obtained.

<4> Closing Means Referring to Figs. 2 and 3, the means for closing the split tubes 31, 31 may be, for example, a known resin binding belt 34 wrapped around the outer periphery of the split tubes 31, 31 to close them.
To prevent the tie belt 34 from coming off the composite flange material 30, the tie belt 34 may be inserted through an insertion hole 31e provided in each of the flanges 31a, 31b and a part of the spacing retaining portion 33 to tie the composite flange material 30 together.

Further, as a closing means for the split barrels 31, 31, a locking claw 31f and a locking hole 31g are formed on the other pair of flanges 31b, 31b formed on the other of the split barrels 31, 31, respectively.
The locking claws 31f can be inserted into the locking holes 31g to lock the split tubes 31, 31 together.

As the closing means for the split cylinders 31, 31, any one of the closing means described above or a combination of a plurality of the closing means can be applied.
Furthermore, the closing means of the split tubes 31, 31 is not limited to the above-mentioned exemplary means, and any known closing means can be applied.

The closing means is not essential, and if a commercially available vinyl tape or the like can be used instead, the merging means described above may be omitted.

<5> Manufacturing of the Composite Tsuba Material Since the composite tsuba material 30 described above has a simple shape and structure, it can be easily manufactured by molding synthetic resin, for example, by resin injection molding or other such molding process.

[How to use composite tsuba material]
Next, a method of using the composite flange material 30 will be described.

1. Manufacturing of the Core Material A method for manufacturing the core material 10 will be described with reference to FIG.

<1> Installation of the composite flange material As shown in FIG. 4(A), in the present invention, the composite flange material 30 has a structure that allows it to be opened, so there is no need to rotate and screw in the end of the bar material 20 as in the conventional method.
In the present invention, the composite tsuba material 30 is prepared with the split tubes 31, 31 in an open state centered on the hinge 31c. The composite tsuba material 30 can be fitted to any position of the bar material 20 by a simple operation of clamping and closing the openings of the split tubes 31, 31 that make up the composite tsuba material 30 from the side of the bar material 20.

When the split cylinders 31 , 31 are clamped to the bar 20 , the female threads 31 d formed on the inner peripheral surfaces of the split cylinders 31 , 31 are fitted into the male threads 21 formed on the outer peripheral surface of the bar 20 .
The female thread 31d of the split tube 31 and the male thread 21 of the bar 20 are not intended to be screwed together by rotation, but rather function to position them in fixed positions without displacing them axially relative to each other.
Therefore, in the present invention, even if plating drips occur on the outer peripheral surface of the bar 20 due to rust prevention treatment such as zinc plating, the composite flange material 30 can be attached to any position of the bar 20.

<2> Closing of the split barrels When closing the pair of split barrels 31, 31, the locking claws 31f are locked into the locking holes 31g and the pair of flanges 31b, 31b are brought into face-to-face contact to close the barrels.
Furthermore, one or more tie belts 34 are wound around the outer periphery of the split tubes 31, 31 to tie the split tubes 31, 31 together so that they cannot be opened.

Conventionally, two independent components, a spacer and a flange, were attached separately to the rod.
In contrast, in the present invention, this can be achieved with only the composite flange material 30 that has both the flange material function and the spacer function, and since the composite flange material 30 is of a clamping type, it does not need to be screwed into the bar material 20.
Therefore, in the present invention, the number of components of the core 10 can be reduced, and the manufacturing costs of the core can also be reduced.
Ultimately, the labor and work time required by workers can be significantly reduced, making the production (assembly) of the core material 10 more efficient.

2. Functions of the Composite Flange Material Various functions of the composite flange material 30 embedded in the consolidated material 51 will be described with reference to FIG.

<1> Spacing retention function The composite flange material 30 has a plurality of spacing retention portions 33 along the axial direction and flanges 31a, 31b that exert a spacing retention function.
Therefore, when the core material 10 is inserted into the pile hole 50 filled with unhardened consolidated material 51, the radially protruding spacing retaining portion 33 and flanges 31a, 31b of the composite flange material 30 perform a spacing retaining function, allowing the rod material 20 to be positioned close to the axis of the pile hole 50.

<2> Effect of flange material When the core material 10 is inserted into the pile hole 50 filled with unhardened consolidated material 51, the radially protruding flange material 32 of the composite flange material 30 increases the adhesion force with the consolidated material 51, thereby increasing the adhesion strength between the rod material 20 and the consolidated material 51.

<3> Why the composite flange material does not open The closing means provided in the composite flange material 30 is intended to temporarily fix the composite flange material 30 to the bar material 20.
The composite flange material 30 is fixed to the bar material 20 by being restrained by the hardened binder 51 .
Therefore, even if a separating force acts between the core material 10 and the consolidated material 51, the hardened consolidated material 51 restrains the composite flange material 30, so there is no need to worry about the split tubes 31, 31 opening up.

10. Core material for small diameter cast-in-place piles (core material)
20... Rod material 21... Male thread 22... Side surface 30... Composite flange material 31, 31... Divided tube 31a... One flange 31b... The other flange 31c... Hinge 31d... Female thread 31e... Through hole 31f... Locking claw 31g... Locking hole 31h... Protrusion 32... Flange material 33... Spacing retaining portion

Claims (8)

A core material for small-diameter cast-in-place piles, which is inserted into a pile hole and has a rod material that adheres to the solidification material filled in the pile hole ,
A rod having at least one of a recess and a protrusion on an outer circumferential surface;
A composite flange member that can be attached to the outer circumferential surface of the bar material by sandwiching the bar material from the side and has both a flange function and a spacing function .
A pair of split tubes that can be held by the rod material,
A flange member protruding from an outer circumferential surface of each of the split cylinders in a circumferential direction;
a plurality of spacing retaining portions intersecting the flange material and protruding radially along the axial direction of the outer peripheral surface of the split tube;
The composite flange material is integrally molded with resin so that the intersection portion of the flange material and the spacing retaining portion is integrated .
Core material for small diameter cast-in-place piles. The core material for small-diameter cast-in-place piles according to claim 1, characterized in that the inner circumferential surfaces of the pair of split tubes are formed in a shape that can fit into the recessed or protruding portions on the outer circumferential surface of the rod. A core material for small-diameter cast-in-place piles as described in claim 1 or 2 , characterized in that a protrusion is formed on the inner surface of the pair of split tubes, and the protrusion abuts against a flat side surface formed along the axial direction on the outer surface of the rod material to restrict free rotation of the composite flange material relative to the rod material. 4. The core material for small-diameter cast-in-place piles according to claim 1, wherein a flange member is formed by a pair of split flanges protruding in the circumferential direction from the outer peripheral surface of each of the split tubes. A core material for small-diameter cast-in-place piles as described in any one of claims 1 to 4 , characterized in that the pair of split tubes have a pair of flanges on both axial ends, and a hinge is formed between one of the flanges. 6. The core material for small-diameter cast-in-place piles according to claim 5 , characterized in that the maximum projection dimension of the flange is formed to be the same as the maximum projection dimension of the spacing retaining portion. The core material for small-diameter cast-in-place piles according to claim 1, characterized in that the composite flange material further comprises a closing means for closing the opening of the split tube. The core material for small-diameter cast-in-place piles as described in claim 7, characterized in that the closing means of the composite flange material is either one or a combination of both of a tie belt, a locking structure of a locking claw and a locking hole provided on the other pair of flanges formed on the other side of the split tube.

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