JP2023047612A - Core material for small-diameter cast-in-place pile - Google Patents

Abstract

To provide a core material for a small-diameter cast-in-place pile which can externally fit and fix a non-closed type composite spacer to a plurality of kinds of reinforcement core materials having different dimensions while reducing the number of components of the core material.SOLUTION: A core material for a small-diameter cast-in-place pile includes a reinforcement core material 20 made of a dimple steel pipe, a composite spacer 30 mounted on its outer peripheral surface, and means 34 for restricting the composite spacer 30, wherein the composite spacer 30 has a pair of split cylinders 31 and 31 capable of holding the reinforcement core material 20 in a non-closed state, a flange material 32 projecting in a circumferential direction on the outer peripheral surfaces of each of the split cylinders 31, and a plurality of interval holding parts radially projecting from the outer peripheral surface of the split cylinders 31, the pair of split cylinders 31 and 31 are connected so as to be openable/closable through a hinge formed between a pair of flanges, and when the pair of split cylinders 31 and 31 are externally fit to the reinforcement core material 20 and closed, the inner diameter of the composite spacer 30 is set to be smaller than the outer diameter of the reinforcement core material 20 so as to form an adjustment gap 35 between the pair of flanges positioned on the opening side of the split cylinders 31.SELECTED DRAWING: Figure 1

Description

The present invention relates to a core material for a small-diameter cast-in-place pile that is inserted into a pile hole filled with a solidifying material such as mortar, and in particular, a small-diameter cast-in-place pile that has both a function of maintaining a gap between the pile hole and a bearing function against the solidifying material. It relates to a core material for

A small-diameter cast-in-place pile is constructed by inserting a core material into a pile hole filled with a solidification material such as mortar, and multiple small-diameter cast-in-place piles are used as tensile reinforcement or compression reinforcement for ground or slopes. Ground reinforcement soil construction methods (for example, root pile construction method, EP root pile construction method) are known (Patent Documents 1 to 3).

A core material 50 used for a small-diameter cast-in-place pile will be described with reference to FIG.
The conventional core material 50 includes a threaded reinforcing bar 60 such as a steel bar of different diameter inserted into the pile hole 40, a spacer 70 attached to the threaded reinforcing bar 60 at an appropriate interval, and a threaded reinforcing bar 60 at an appropriate interval. and a threaded collar 80 attached thereto.
The threaded rebar 60 forms a thread over its entire length.
The spacer 70 includes a cylindrical portion 71 that can be screwed onto the threaded reinforcing bar 60 and a plurality of blades 72 that are provided in the shape of arrow feathers along the axial direction of the outer peripheral surface of the cylindrical portion 71 . A plurality of vanes 72 exhibit the function of keeping the distance between the threaded reinforcing bars 60 with respect to the pile holes 40 .
A casting collar member 80 has a tubular portion 81 that can be screwed onto the screw reinforcing bar 60 and an enlarged diameter portion 82 that protrudes radially from the outer peripheral surface of the tubular portion 1 .
The spacer 70 and the collar material 80 form an internal thread at the center thereof, and by rotating these members, the mounting position of the screw reinforcing bar 60 is adjusted along the axial direction.

JP-A-55-136322 Japanese Utility Model Laid-Open No. 61-6531 JP-A-58-17931

The core material for small-diameter cast-in-place piles described above has the following problems.
<1> The number of component parts of the core material 50 is large, and the material cost of the core material 50 is high.
<2> Since both the spacer 70 and the flange member 80 are of the screw-in type, manufacturing the core member 50 takes a lot of time and effort.
In particular, in order to restrain the free rotation of the collar material 80 after installation, a wedge body must be driven between the threaded reinforcing bar 60 and the collar material 80 to fix it. It takes.
<3> Since the spacer 70 and the flange member 80 are of a screw-in type, it is necessary to manufacture a plurality of types according to the diameter of the screw reinforcing bar 60 .
Therefore, not only is the manufacturing cost of the spacer 70 and the flange member 80 high, but also the individual management of standard products with different diameters is troublesome.
<4> Although the screw reinforcing bar 60 is a standard product, some manufacturing errors occur.
If the manufacturing error of the screw reinforcing bar 60 becomes large, the spacer 70 and the collar material 80 cannot be screwed together.

The present invention has been made in view of the above points, and its object is to reduce the number of component parts of the core material and to provide a non-closed composite for multiple types of reinforcing core materials with different dimensions. To provide a core material for a small-diameter cast-in-place pile capable of mounting and fixing a spacer.

The present invention is a core material for a small-diameter cast-in-place pile that is used by inserting it into a pile hole and adheres to the consolidation material filled in the pile hole, and is inserted into the pile hole and has at least a recess on the outer peripheral surface. or a reinforcing core member having an element of any one of convex portions, a composite spacer immovably attached to the outer peripheral surface of the reinforcing core member by sandwiching the reinforcing core member from the side of the reinforcing core member, and tightening and restraining the composite spacer. The composite spacer comprises a pair of split cylinders that can be held in a non-closed state with respect to the reinforcing core material, and a flange material protruding along the circumferential direction from the outer peripheral surface of each split cylinder. and a plurality of space holding portions protruding radially along the axial direction of the outer peripheral surface of the split cylinder, and flanges are formed on both end edges of the pair of split cylinders along the axial direction, respectively, The pair of split cylinders are connected so that they can be opened and closed via a hinge formed between one of the flanges. The inner diameter of the composite spacer is made smaller than the outer diameter of the reinforcing core so as to form an adjustment gap between the pair of flanges.
In another aspect of the present invention, the split cylinder constituting the composite spacer has, on its inner peripheral surface, one or more pressing protrusions capable of pressing the outer peripheral surface of the reinforcing core member.
In another aspect of the present invention, a pair of flanges located on the hinge side of the composite spacer are formed with locking holes and locking claws that can be locked into the locking holes.
In another aspect of the present invention, the maximum overhang dimension of the hinge-side and opening-side flanges constituting the composite spacer may be formed to be the same as the maximum overhang dimension of the gap retaining portion.
In another aspect of the present invention, the intersecting portion of the gap holding portion and the flange member protruding from the outer peripheral surface of the split cylinder constituting the composite spacer are integrated.
In another aspect of the invention, a restraining belt can be used as the restraining means for the composite spacer.
In another aspect of the invention, the reinforcing core can be a dimpled steel pipe or a threaded steel bar.

The present invention has at least one of the following effects.
<1> Since the composite spacer can be used as both a conventional spacer and a collar material, it is possible to reduce the number of component parts of the core material for a small-diameter cast-in-place pile.
<2> Since the composite spacer is not of a screw-in type, it is possible to assemble the core material for a small-diameter cast-in-place pile by a simple operation of sandwiching the opening of the composite spacer from the side of the reinforcing core material.
<3> By making the inner diameter of the composite spacer smaller than the outer diameter of the reinforcing core material, a single composite spacer can be attached to a plurality of types of reinforcing core materials having different diameters, and at the same time, Composite spacers can be attached by absorbing manufacturing errors.
<4> Since there is no need to manufacture composite spacers that match the diameter of the reinforcing core material, the number of types of composite spacers can be greatly reduced.
<5> Since the pressing protrusions provided on the inner peripheral surface of the split cylinder constituting the composite spacer press against the outer peripheral surface of the reinforcing core material, the reinforcing core material is restrained from being displaced in the circumferential and axial directions. Composite spacers can be attached.
<6> When the pair of flanges located on the hinge side are brought into contact with each other to engage the locking hole with the locking pawl, the composite spacer can be elastically temporarily fixed to the outer peripheral surface of the reinforcing core member.
Therefore, the work of aligning the composite spacer and the reinforcing core member and the work of fixing the composite spacer using the restraining means can be performed stably and efficiently without worrying about the composite spacer falling off.
<7> When attached to the reinforcing core material, the adjustment gap formed between the flanges on the opening side of the composite spacer functions as a passage for the consolidation material, so when injecting the consolidation material, the entire area of the pile hole The consolidation material can be injected without gaps.
<8> By matching the maximum overhang dimension of the flange with the maximum overhang dimension of the gap holding portion, the flange can be provided with a gap holding function.
<9> By integrating the intersecting portion of the brim material and the space keeping portion, the strength of the brim material and the space keeping portion can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing of the core material for small-diameter cast-in-place piles which concerns on Example 1 of this invention It is an explanatory view of the core material, (A) is a perspective view of a hollow part with a part broken, (B) is an explanatory view of a form in which a plurality of hollow parts are formed on the same circumference of the pipe body, (C) is Explanatory drawing of a configuration in which rows of a plurality of recesses adjacent in the circumferential direction are formed with phase differences in the tube axial direction. Sectional view of III-III in Fig. 1 Overall perspective view of composite spacer and restraint belt Perspective view of deployed composite spacer Explanatory drawing of the manufacturing method of the core material in which the composite spacer is wrapped around the reinforcing core material Explanatory drawing of the manufacturing method of the core material that restrains and fixes the composite spacer with the restraint belt Sectional view of VIII-VIII in Fig. 1 Explanatory drawing of core material for small-diameter cast-in-place pile according to Example 2 of the present invention Explanatory drawing of the conventional root pile construction method

[Example 1]
<1> Core material for small-diameter cast-in-place pile Referring to FIG. 20, a composite spacer 30 that can be attached to the outer peripheral surface of the reinforcing core member 20 by sandwiching the reinforcing core member 20 from the side thereof, and restraining means that tightens and restrains the composite spacer 30.

<2> Reinforcing Core Material The reinforcing core material 20 includes steel pipes such as dimple steel pipes, stepped steel pipes having steps or depressions on the outer peripheral surface, obliquely stepped steel pipes, deformed reinforcing bars having knots and ribs, deformed steel bars, and the like. Steel bars can be used.
The reinforcing core material 20 can be used as long as it has at least one type of element, either concave or convex, on the outer peripheral surface.

In this example, a form in which the reinforcing core material 20 is a dimpled steel pipe having a plurality of depressions 22 formed on the outer peripheral surface of the pipe main body 21 will be described.

The reinforcing core member 20 is a hollow tubular body with both ends open, and the diameter _d1 and the body thickness t of the reinforcing core member 20 can be appropriately selected.
Practically, a steel pipe having a diameter _d1 of 40A (diameter 48.6 mm) and a body thickness t of 6 mm is suitable for the reinforcing core member 20 so that manual construction is possible.

<2.1> Recessed Portion The outer peripheral surface of the pipe main body 21 of the reinforcing core member 20 is not flat, but has an uneven shape to enhance adhesion with the consolidating material 41 .
The reinforcing core material 20 made of the dimpled steel pipe of this example has a plurality of depressions 22 along the pipe axial direction and the circumferential direction of the pipe main body 21 .

<2.2> Structural Example of Recessed Portion To explain the recessed portion 22 illustrated in FIG. In addition, a columnar groove 22b deeper than the flat portion is formed in the center of the flat portion 22a.
The size of the flat portion 22a and the depth of the columnar groove 22b can be appropriately selected.

In this example, the recessed portion 22 has both the flat portion 22a and the columnar grooves 22b.

When the recessed portion 22 has the columnar grooves 22b, the solidifying material 25 enters the columnar grooves 22b, thereby further improving the adhesion of the recessed portion 22. As shown in FIG.

<2.3> Arrangement Example of Recess FIG. 2 shows an arrangement example of the recess 22 . 4B shows a configuration in which a plurality of recessed portions 22 are formed in rows along the axial direction of the pipe body 21 at regular intervals, and formed at regular intervals on the same circumference of the pipe body 21. , and FIG. 2C shows a form in which rows of a plurality of recessed portions 22 adjacent in the circumferential direction are formed with a phase difference in the tube axial direction.

<2.4> Number of Dimples Formed in Circumferential Direction The number of dimples 22 formed at regular intervals in the circumferential direction of the pipe body 21 can be selected as appropriate.
FIG. 3 shows a configuration in which three depressions 22 are formed along the circumferential direction of the pipe body 21 . One or more hollow portions 22 along the circumferential direction of the pipe body 21 may be provided.

<2.5> Method for Forming Recessed Portion The recessed portion 22 can be formed, for example, by hot roll forming using a steel pipe forming roll having projections on its surface.

<3> Composite Spacer The composite spacer 30 will be described with reference to FIGS.
The composite spacer 30 is a composite material having both a brim function and a spacing function.
The composite spacer 30 comprises a pair of split cylinders 31, 31 with a hinge that can be held in an unclosed state with respect to the reinforcing core member 20, and split cylinders 31, 31 protruding along the circumferential direction from the central outer peripheral surfaces of the split cylinders 31, 31. It comprises a flange material 32 consisting of flanges 32a, 32a, and a plurality of interval holding portions 33 protruding along the axial direction on the outer peripheral surfaces of the split cylinders 31, 31. As shown in FIG.

<3.1> Split Tubes The split tubes 31, 31 are a pair of half-cylinders obtained by dividing a cylinder that can be attached to the outer peripheral surface of the reinforcing core member 20 in the axial direction.
Each split cylinder 31 has flanges 31 a and 31 b , a split brim 32 a , and a gap holding portion 33 .
The pair of split cylinders 31, 31 can be easily manufactured by, for example, synthetic resin molding such as resin injection molding.

<3.1.1> Flanges Each of the split cylinders 31, 31 has semicircular flanges 31a, 31b bent outward at both ends along the axial direction.

<3.1.2> Hinge The ends of one pair of flanges 31a, 31a are integrally connected via a hinge 31c, and the split cylinders 31, 31 can move (open and close) around the hinge 31c. is.

In the following description, the side of the flanges 31a, 31a on which the hinge 31c is formed is referred to as the "hinge side," and the side of the flanges 31b, 31b, on which the hinge is not formed, is referred to as the "opening side."

<3.1.3> Locking Claw and Locking Hole A pair of flanges 31a, 31a on the hinge side can be in contact with each other.
The flanges 31a, 31a on the hinge side are formed with a locking claw 31f and a locking hole 31g, which can be engaged and locked with each other. 31f is locked in the locking hole 31g.
The pair of flanges 31b, 31b on the opening side are not provided with the locking claws 31f and the locking holes 31g.

<3.1.4> Insertion hole A part of the flanges 31a and 31b has an insertion hole 31e, and a restraining belt 34, which is restraining means described later, can be inserted through the plurality of insertion holes 31e. A part of the gap holding portion 33 may also be provided with the insertion hole 31e.

<3.2> Collar Material Divided collars 32a, 32a protrude along the circumferential direction on the central outer peripheral surface of each of the split cylinders 31, 31. As shown in FIG.

In this example, the three-dimensional shape of the collar material 32 is disk-shaped, but the three-dimensional shape of the collar material 32 is not particularly limited, but may be a polygonal nut shape.

The projecting dimension of the collar material 32 is smaller than the projecting dimension of the interval holding portion 33 (or the diameter of the pile hole 40). This is to prevent the space of the pile hole 40 from being blocked by the collar material 32 .
The projecting dimension and axial length of the flange member 32 can be selected as appropriate.

<3.3> Space Holding Portion The space holding portion 33 is a plate-shaped pressing projection formed along the axial direction on the outer peripheral surface of each split cylinder 31, and has a space holding function (centering function).
The interval holding part 33 has a semicircular shape so that it can be easily moved within the pile hole 40 .
In this example, two space holding portions 33 radially protrude from the outer peripheral surface of each split tube 31 along the axial direction, but the number of space holding portions 33 to be formed can be appropriately selected.

Further, by matching the maximum overhang dimension of each of the flanges 31a and 31b to the same dimension as the maximum overhang dimension of the semicircular space holding portion 33, the flanges 31a and 31b can be provided with a space holding function. can.

<3.4> Dimensional Relationship between Collar Material and Space Holding Portion The diameter is made slightly smaller than the hole diameter of the pile hole 40 .

<3.5> Reason for Integrating Crossing Portion of Collar Material and Space Holding Portion The crossing portion of the flange member 32 projecting from the outer peripheral surface of each of the split cylinders 31, 31 and the space holding portion 33 is integrally formed.
The reason why the intersecting portions of the brim member 32 and the interval holding portion 33 are integrated is to reinforce each other and increase the strength of the brim member 32 and the interval holding portion 33 .

<3.6> Peripheral Groove Referring to FIG. 5, in the center of the inner peripheral surface of each split cylinder 31, a peripheral groove 31d is formed as a trace of molding of the split collar 32a.

<3.7> Pressing Protrusion Description will be made with reference to FIG. The inner peripheral surface of each split cylinder 31 has a single or a plurality of pressing projections 31h parallel to the tube axis direction with the circumferential groove 31d interposed therebetween.
The pressing protrusion 31 h is a protrusion that can press the outer peripheral surface of the reinforcing core member 20 .
The projecting dimension, width dimension, and overall length of the pressing projection 31 h can be appropriately selected according to the uneven shape of the outer peripheral surface of the reinforcing core member 20 .

The pressing protrusions 31h may be formed on the upper and lower inner peripheral surfaces of the split cylinder 31 with the circumferential groove 31d interposed therebetween, or may be formed on either the upper or lower inner peripheral surface of the split cylinder 31 with the circumferential groove 31d interposed therebetween. may be formed.

In this example, the pressing protrusion 31h is formed in a columnar shape along the axial direction of the split tube 31, and the columnar pressing protrusion 31h is pressed against the flat portion 22a or the columnar groove 22b of the recess portion 22 formed on the outer peripheral surface of the reinforcing core member 20. It shows a possible formed form.

The pressing projection 31h may be hemispherical instead of columnar, and the shape of the pressing projection 31h is not particularly limited as long as it can press the outer peripheral surface of the reinforcing core member 20 .

The number of pressing protrusions 31h formed in the circumferential direction of the inner peripheral surface of the split tube 31 may be formed in the same number so as to correspond to the depressions 22 formed in the circumferential direction of the reinforcing core material 20. The number of press protrusions 31h formed in the circumferential direction of 31 may be less than or greater than the number of recesses 22 formed.

<4> Dimensional relationship between the outer diameter of _the reinforcing core material and the inner diameter of the composite spacer Referring to _FIG . Instead of having the same diameter, the inner diameter d ₂ of the composite spacer 30 is set to be smaller than the outer diameter d ₁ of the reinforcing core 20 (d ₁ >d ₂ ).
In other words, the circumferential length of the inner circumferential surface of the split cylinder 31 constituting the composite spacer 30 is set to be shorter than the circumferential length of the outer circumferential surface of the reinforcing core member 20 .

<4.1> Adjustment gap The diameter difference (peripheral length difference) between the composite spacer 30 and the reinforcing core material 20 is provided by closing the pair of split cylinders 31, 31 on the reinforcing core material 20. This is because sometimes the pair of flanges 31b, 31b located on the opening side of the composite spacer 30 do not close (unclosed), and the adjustment gap 35 is formed between the opposing surfaces of the pair of flanges 31b, 31b.

<4.2> Reason for Forming Adjustment Gap The composite spacer 30 used in the present invention is not manufactured individually according to the specific diameter of the reinforcing core member 20 .
The composite spacer 30 used in the present invention is adjusted between a pair of flanges 31b, 31b located on the opening side when mounted on the reinforcing core 20 so that it can be attached to a plurality of types of reinforcing core 20 having different diameters. A gap 35 is formed.
The adjustment gap 35 is obtained from the diameter difference (peripheral length difference) between the composite spacer 30 and the reinforcing core member 20 .

<5> Constraint Means The restraint means is for fixing the divided cylinders 31, 31 constituting the composite spacer 30 to the reinforcing core 20 so as to be immovable (non-slidable and non-rotatable) in the axial and circumferential directions. It is a member.
Referring to FIG. 4, as a restraining means for the composite spacer 30, for example, a restraining belt 34 made of known resin or the like is used, and the restraining belt 34 is wound around the outer circumferences of the split cylinders 31, 31 for use.
Insertion holes 31e are formed in each of the flanges 31a and 31b and part of the interval holding portion 33 so that the restraint belt 34 does not come off from the composite spacer 30, and one or more restraint belts 34 are inserted through these insertion holes 31e. and tighten.

[Manufacturing method of core material]
A method of manufacturing the reinforcing core member 20 will be described with reference to FIGS.

<1> Composite spacer exterior work Since the composite spacer 30 has a hinge structure that can be opened, the flanges 31b, 31b sides of the split cylinders 31, 31 are opened around the hinge 31c, and the opened composite spacer The opening of 30 is sandwiched from the side of the reinforcing core material 20 to cover it.

<2> Temporarily fixing the composite spacer With the reinforcing core material 20 sandwiched, the flanges 31a, 31a on the side of the hinge 31c are pinched with fingers in the tangential direction until the locking claws 31f are locked in the locking holes 31g. sandwiched between
By locking the locking claw 31f into the locking hole 31g, one flange 31a, 31a maintains the contact surface state. By keeping the one flanges 31a, 31a in contact with each other, the pair of split cylinders 31, 31 are elastically held on the outer peripheral surface of the reinforcing core material 20 due to the elasticity of the one flanges 31a, 31a. , the composite spacer 30 can be temporarily fixed to the outer peripheral surface of the reinforcing core member 20 only by this elastic holding force.
Therefore, it is not necessary for the operator to hold and support the composite spacer 30 by hand.

Even if the pair of split cylinders 31, 31 are mounted on the reinforcing core material 20, there is a diameter difference (peripheral length difference) between the composite spacer 30 and the reinforcing core material 20. The pair of flanges 31b, 31b are not closed, and an adjustment gap 35 is formed between the pair of separated flanges 31b, 31b.

<3> Alignment Work of Composite Spacer and Reinforcing Core Material When temporarily fixing the composite spacer 30, the composite spacer 30 is moved slightly in the circumferential direction or axial direction with respect to the reinforcing core material 20, and the composite spacer 30 is The composite spacer 30 is aligned with the reinforcing core member 20 so that the pressing protrusions 31 h formed on the inner peripheral surface of the reinforcing core member 20 are aligned with the depressions 22 of the reinforcing core member 20 .
Since the composite spacer 30 is temporarily fixed to the outer peripheral surface of the reinforcing core member 20 by self-elasticity, the alignment work with the reinforcing core member 20 can be performed without worrying that the composite spacer 30 will fall off.

<4> Composite spacer fixing operation Merely temporarily fixing the composite spacer 30 displaces the composite spacer 30 along the circumferential direction and the axial direction of the reinforcing core member 20 .
Therefore, by tightening the restraining belt 34 inserted through the insertion hole 31 e and restraining the restraining belt 34 to the outer circumference of the split cylinders 31 , 31 constituting the composite spacer 30 , the composite spacer 30 is opened to the reinforcing core member 20 . can be permanently fixed.

Even if the composite spacer 30 is tightened with the restraint belt 34, the adjustment gap 35 formed between the facing surfaces of the pair of flanges 31b, 31b is slightly narrowed, but the pair of flanges 31b, 31b do not come into contact with each other.
Since the composite spacer 30 is temporarily fixed to the outer peripheral surface of the reinforcing core member 20 by self-elasticity, the restraint belt 34 can be fixed without worrying about the composite spacer 30 falling off.

The core member 10 is manufactured by fixing the composite spacer 30 to an arbitrary position of the reinforcing core member 20 in the manner described above.

<5>Characteristics of core material Conventionally, a threaded spacer and a collar material were individually screwed into and attached to a threaded reinforcing bar.
On the other hand, in the present invention, only the composite spacer 30 having both a collar function and a spacer function can cope with this problem.
Therefore, in the present invention, the number of component parts of the reinforcing core member 20 can be reduced, and the manufacturing cost of the core member can also be reduced.
Ultimately, it is possible to greatly reduce the labor and work hours of workers, and to improve the efficiency of the manufacturing (assembling) work of the reinforcing core member 20 .

[Construction method of small-diameter cast-in-place piles]
An example of a method for constructing a small-diameter cast-in-place pile will be described with reference to FIG.

<1> Drilling Step A boring machine is used to drill a pile hole 40 with a predetermined depth.

<2> Step of Inserting Core Material The already described core material 10 is inserted into the pile hole 40 .

<3> Step of Injecting Consolidation Material The reinforcing core material 20 constituting the core material 10 is used as a substitute for the injection hose.
A consolidating material 41 such as mortar or cement milk is injected from the bottom of the pile hole 40 through the reinforcing core 20 to complete the construction of the small-diameter cast-in-place pile.

The composite spacer 30 is positioned in the transverse direction of the pile hole 40, and the adjustment gap 35 formed between the pair of flanges 31b, 31b of the composite spacer 30 serves as a passage for the consolidation material 41. As shown in FIG.
Therefore, since the consolidating material 41 discharged to the bottom of the hole can flow through the adjustment gap 35 of the composite spacer 30 , the consolidating material 41 can be injected into the entire area of the pile hole 40 .

<4> Adhesion between Reinforcing Core Material and Consolidating Material The reinforcing core material 20 adheres to the consolidating material 41 on the outer peripheral surface of the pipe body 21 formed in an uneven shape.
In particular, since the recessed portion 22 formed on the outer peripheral surface of the reinforcing core material 20 and the recessed portion 22 formed on the inner peripheral surface of the reinforcing core material 20 are in close contact with the consolidating material 41, there is no gap between the reinforcing core material 20 and the consolidating material. high adhesion (frictional resistance) can be obtained.

[Function of composite spacer]
Various functions of the composite spacer 30 embedded in the consolidation material 41 will be described with reference to FIG.

<1> Function of Adjusting Holding Dimension by Composite Spacer As described above, the composite spacer 30 is adjusted such that the inner diameter _d2 of the composite spacer 30 is smaller than the outer diameter _d1 of the reinforcing core member 20. and the reinforcing core member 20 (FIG. 6), the composite spacer 30 can exhibit the function of adjusting the holding dimension.
Therefore, since one composite spacer 30 can be attached to a plurality of types of reinforcing core members 20 having different diameters, the number of types of composite spacers 30 can be reduced.

Furthermore, when a dimpled steel pipe is used for the reinforcing core material 20, dimensional differences occur due to manufacturing errors even with the same standard product.
By providing the composite spacer 30 with a holding dimension adjusting function, the composite spacer 30 can absorb the manufacturing error of the reinforcing core member 20 and can be fixed in close contact with the outer peripheral surface of the reinforcing core member 20 .

<2> Spacing Maintaining Function Referring to FIG. 8, the composite spacer 30 has a plurality of spacing retaining portions 33 along the axial direction and flanges 31a and 31b exhibiting a spacing retaining function.
Therefore, when the reinforcing core material 20 is inserted into the pile hole 40 filled with the unhardened consolidation material 41, the gap holding portion 33 and the flanges 31a and 31b projecting in the radial direction of the composite spacer 30 perform the gap holding function. The reinforcing core material 20 can be arranged at a position close to the axis of the pile hole 40. - 特許庁

<3> Extraction Resistance by Collar Material The consolidating material 41 filled in the pile hole 40 adheres to the outer peripheral surface of the composite spacer 30 and hardens.
Since the flange material 32 projecting in the radial direction increases the adhesive force with the consolidation material 41 and the upper surface of the flange material 32 functions as a resistance surface, the core material 10 is pulled out with a greater resistance.

<4> Prevention of Mouth Opening of Composite Spacer The binding material 41 hardened in close contact with the outer peripheral surface of the composite spacer 30 constrains the composite spacer 30 .
Therefore, even if a separation force acts between the reinforcing core member 20 and the consolidation material 41, the restraint action of the hardened consolidation material 41 reliably prevents the opening of the composite spacer 30. FIG.

[Example 2]
Other embodiments will be described below. In the description, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

<1> Reinforcing Core Material Made of Steel Bar FIG. 9 illustrates a configuration in which the reinforcing core material 20 is a threaded steel bar (threaded reinforcing bar) having an external thread 23 .
The reinforcing core member 20 can also be applied to a threaded steel bar having a flat side surface 24 along the axial direction on its outer peripheral surface.

<2> Composite spacer The composite spacer 30 used in this example has the same structure as in the first embodiment. , 31, a plurality of gap holding portions 33 projecting axially from the outer peripheral surfaces of the divided cylinders 31, 31, and the divided cylinders 31, 31. and a binding belt 34 which is a restraining means for closing.

In this example, the inner diameter of the composite spacer 30 is set to be smaller than the outer diameter of the reinforcing core member 20, and when the composite spacer 30 is held and fixed to the outer peripheral surface of the reinforcing core member 20, Since the formation of the adjustment gap 35 between the opposing surfaces of the pair of flanges 31b, 31b is the same as in the first embodiment, detailed description thereof will be omitted.

<3> Engagement Structure of Reinforcing Core Material and Composite Spacer By attaching the composite spacer 30 to the reinforcing core material 20, the pressing protrusions 31h formed on the inner peripheral surface of the composite spacer 30 are recessed on the outer peripheral surface of the reinforcing core material 20. The composite spacer 30 can be secured to the reinforcing core 20 by engaging (the valley between the external threads 23).

<4> Effect of this example This example also has the same effect as that of the first example.
Especially in this example, it is possible to correspond to several types of reinforcing core members 20 made of threaded steel bars having different diameters.

10: Core material for small-diameter cast-in-place pile (core material)
20 Reinforcing core material 21 Tube main body 22 Recessed portion 22a Flattened portion 22b of recessed portion Columnar groove 30 of recessed portion Composite spacers 31, 31 Split tube 31a Flange 31b on one side Flange 31c on the other side Hinge 31d Circumferential groove 31e Insertion hole 31f Locking claw 31g Locking hole 31h Pressing projection 32 Collar member 33 Spacing portion 34 Restraining belt

Claims (8)

A core material for a small-diameter cast-in-place pile that is used by inserting it into a pile hole and adheres to the consolidation material filled in the pile hole,
A reinforcing core material inserted into the pile hole and having at least one type of element, either a concave portion or a convex portion, on the outer peripheral surface;
a composite spacer immovably attached to the outer peripheral surface of the reinforcing core material by sandwiching the reinforcing core material from the side thereof;
and a restraining means for tightening and restraining the composite spacer,
The composite spacer includes a pair of split cylinders that can be held in an unclosed state with respect to the reinforcing core material,
a flange member protruding along the circumferential direction on the outer peripheral surface of each of the split cylinders;
a plurality of space holding portions protruding radially along the axial direction of the outer peripheral surface of the split cylinder,
forming flanges on both ends along the axial direction of the pair of split cylinders,
connecting the pair of split cylinders so as to be able to open and close via a hinge formed between the one flanges;
The inner diameter of the composite spacer is adjusted to the reinforcing core material so that an adjustment gap is formed between the pair of flanges positioned on the opening side of the pair of split cylinders when the pair of split cylinders is wrapped around the reinforcing core material and closed. characterized by having a small diameter dimensional relationship with respect to the outer diameter of
Core material for small diameter cast-in-place piles. The divided cylinder constituting the composite spacer has, on its inner peripheral surface, one or more pressing projections capable of pressing the outer peripheral surface of the reinforcing core material, and the pressing projections are pressed against the outer peripheral surface of the reinforcing core material to press the reinforcing core. The core material for a small-diameter cast-in-place pile according to claim 1, characterized in that a composite spacer is held on the outer peripheral surface of the material. 3. The small hinge according to claim 1, wherein a pair of flanges located on the hinge side of said composite spacer are formed with locking holes and locking claws that can be locked into said locking holes. Core material for cast-in-place piles. 2. The small-diameter place according to claim 1, wherein the maximum overhang dimension of the flanges on the hinge side and the opening side constituting the composite spacer is set to the same dimension as the maximum overhang dimension of the space holding portion. Core material for driving piles. 2. The core material for a small-diameter cast-in-place pile according to claim 1, wherein the intersecting part of the flange material protruding to the outer peripheral surface of the split tube constituting the composite spacer and the gap holding part are integrated. The core material for a small-diameter cast-in-place pile according to claim 1, wherein the restraining means of the composite spacer is a restraining belt. The core material for a small-diameter cast-in-place pile according to claim 1, wherein the reinforcing core material is a dimpled steel pipe having a plurality of depressions formed on the outer peripheral surface of the pipe body. The core material for a small-diameter cast-in-place pile according to claim 1, wherein the reinforcing core material is a threaded steel bar.

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