JP4695448B2 - Assembly rebar and pile construction method using the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an assembly reinforcing bar suitable for construction of a pile whose tip is expanded, and a pile construction method using the same.

2. Description of the Related Art Conventionally, as an assembly reinforcing bar (also referred to as “rebar bar”) used for construction of a cast-in-place pile, for example, a cylindrical assembly reinforcing bar described in Patent Document 1 is known.
Japanese Patent Laying-Open No. 2003-166238 (paragraphs 0005 to 0007, FIG. 1)

  By the way, in recent years, development of bottom-diameter enlarged piles that increase the diameter of the bottom part (tip part) of the pile and increase the tip support force has been actively conducted. Of these, for pile holes, for example, a drilling device capable of expanding the diameter of the cutting edge is used, or a method of expanding the diameter of only the bottom (tip) of the pile hole by injecting a jet water flow from the tip of the drill has been developed. ing.

  However, when a cylindrical assembly rebar is inserted into such a pile hole and concrete or the like is placed, the rebar is not arranged in the expanded diameter part of the bottom of the pile hole. Cracks may occur at the boundary with the part, and the edges may be cut off. If the edge is cut, a sufficient tip support force cannot be obtained even if the bent bottom is expanded.

  The present invention has been made to solve such a problem, and provides an assembled reinforcing bar capable of easily arranging a reinforcing bar in a diameter-enlarged portion of a bottom portion of a pile hole and a method for constructing a pile using the same. The task is to do.

The invention according to claim 1 of the present application is an assembly reinforcing bar disposed in a pile hole whose bottom portion has an enlarged diameter, and the narrow diameter portion disposed from the narrow diameter portion of the pile hole to the bottom portion of the pile hole. Reinforcing bars, a plurality of enlarged diameter part reinforcing bars connected to a position spaced upward from the lower end of the narrow diameter part reinforcing bars, and arranged in the enlarged diameter part of the pile hole, and the narrow diameter part reinforcing bars are piles in the state prior to contact with the bottom surface of the hole, the projecting from the lower end of small diameter rebar, a slide member slidably disposed relative to the small diameter rebar, one end pivoted on said radially enlarged portion reinforcing bar And a connecting member that is rotatably connected to the slide member at the other end side, and the enlarged-diameter rebar is in a state in which the narrow-diameter rebar is in contact with the bottom surface of the pile hole And having a fixing part located closer to the center of the pile hole than the narrow-diameter part reinforcing bar, The plurality of enlarged-diameter rebars are connected to the fixing unit via the connecting member, and the fixing member is pulled down by the slide member in a state before the slide member contacts the bottom surface of the pile hole. So that the slide member comes into contact with the bottom surface of the pile hole and slides so as to approach the narrow-diameter rebar so that the plurality of large-diameter rebars are opened downward from above. It rotates and arrange | positions at the said enlarged diameter part, It is characterized by the above-mentioned .

  According to such a configuration, in a state before the assembly rebar contacts the bottom surface of the pile hole, the enlarged-diameter rebar is rotatably connected to the narrow-diameter rebar with the fixing portion facing downward, and The slide member is rotatably connected to the fixing portion via a connecting member. At this time, the enlarged diameter portion reinforcing bar is in a state in which the portion arranged in the enlarged diameter portion of the pile hole is directed upward.
  When the assembly rebar further descends and the slide member comes into contact with the bottom surface of the pile hole, the slide member slides relatively upward with respect to the narrow-diameter portion rebar, and the enlarged-diameter portion rebar is lowered via the connecting member. The force that was pulled on will be loosened. As a result, the fixing part rotates in the center direction of the pile around the connection position with the narrow-diameter part reinforcing bar, and the part located above the fixing part rotates in the radially outward direction of the pile, and the enlarged diameter part reinforcing bar Will be arranged in the enlarged part of the pile hole.
  In addition, it is preferable that a diameter expansion part reinforcing bar makes parts other than a fixing part longer than a fixing part. If it does in this way, when a slide member contacts the bottom face of a pile hole, it will become easy to rotate a diameter-expansion part reinforcing bar to the diameter outside direction of a pile with dead weight. Moreover, it is preferable to dug the connection part of the narrow diameter part of a pile hole and an enlarged diameter part so that rotation of an enlarged diameter part reinforcement may not be inhibited.

  Here, it is preferable that the slide member is disposed inside the narrow-diameter portion reinforcing bar. If the sliding member is placed inside the narrow-diameter rebar, the outer diameter of the entire rebar can be reduced, and the diameter of the pile hole can be reduced to reduce unnecessary excavation and less concrete placement. can do. Therefore, cost reduction and construction period shortening can be achieved.
  Moreover, it is preferable to arrange | position a slide member concentrically with a narrow diameter part reinforcement. If it does in this way, a slide member can be smoothly slid with respect to a narrow diameter part reinforcement.
  Note that the slide member is preferably formed in a cylindrical shape by combining a plurality of rod-shaped reinforcing bars and a plurality of hoop bars. If it does in this way, while being easy to arrange | position concentrically with a narrow diameter part reinforcement, procurement of a material is also easy.

Further, the invention according to claim 2 is the assembled reinforcing bar according to claim 1, wherein the plurality of enlarged diameter portion reinforcing bars are such that both the narrow diameter portion reinforcing bar and the slide member are in contact with the bottom surface of the pile hole. In the state, it is arranged substantially horizontally.

The invention according to claim 3 of the present application is the assembled reinforcing bar according to claim 1 or 2 , further comprising a reinforcing member that connects the enlarged diameter portion reinforcing bars adjacent to each other, and the reinforcing member is bendable. It is comprised by these.

According to this structure, since the adjacent enlarged diameter part reinforcement is connected by the reinforcement member, the force which acts on the enlarged diameter part of a pile can be handled by several enlarged diameter part reinforcement. In other words, the force acting on the enlarged diameter portion of the pile can be dispersed. Therefore, the bearing capacity of the pile can be increased.
Further, since the reinforcing member is configured to be bendable, the reinforcing member is folded when the interval between the enlarged-diameter rebars is narrow, and expands following the expansion of the enlarged-diameter reinforcing bar to increase the interval. be able to. Therefore, it is possible to suitably connect the enlarged-diameter reinforcing bars that expand radially in the enlarged-diameter portion of the pile hole.

  Here, it is preferable that the reinforcing member is disposed so as to connect at least the distal end portions of the enlarged diameter portion reinforcing bars. If it does in this way, the effect which restrains a pile can be heightened. Further, the reinforcing member may be arranged in a plurality of stages. If it does in this way, the support power of a pile can be raised further.

The invention according to claim 4 of the present application is the assembled reinforcing bar according to claim 3 , wherein the reinforcing member is configured such that at least two rod-like members are rotatably connected to each other, and both end portions of the reinforcing member are In addition, it is connected to the adjacent enlarged-diameter reinforcing bars so as to be rotatable.

  According to this configuration, the reinforcing member is configured such that at least two rod-like members are rotatably connected to each other, and both end portions of the reinforcing member are rotatably connected to the adjacent enlarged-diameter reinforcing bars. Therefore, in a state in which the enlarged-diameter rebar is not deployed (that is, the state before the slide member contacts the bottom of the pile hole), the expanded-diameter rebar is folded by the slide member and the connecting member. As it expands, the reinforcing member is stretched in a straight line. That is, according to this reinforcing member, adjacent enlarged diameter part reinforcements can be connected, following the expansion of the space | interval of enlarged diameter part reinforcements in the enlarged diameter part of a pile hole.

The invention according to claim 5 of the present application is the assembled reinforcing bar according to claim 3 , wherein the reinforcing member is formed of a wire.

  According to such a configuration, since the reinforcing member is composed of a wire, in a state where the enlarged diameter portion reinforcing bar is not deployed, the reinforcing member is bent (or bent), and the enlarged diameter portion reinforcing bar is deployed. As a result, the wire is stretched in a straight line. That is, according to this reinforcing member, adjacent enlarged diameter part reinforcements can be connected, following the expansion of the space | interval of enlarged diameter part reinforcements in the enlarged diameter part of a pile hole.

The invention which concerns on Claim 6 is the construction method of the bottom enlarged diameter pile using the assembly reinforcing bar of any one of Claim 1 to 5 , Comprising: The pile which constructs the pile hole which the bottom expanded It includes a hole construction step and an assembly rebar insertion step of inserting the assembly rebar into the pile hole.

According to such a method, the bottom diameter is increased by a simple method of constructing a pile hole having a diameter expanded at the bottom and inserting the assembly reinforcing bar according to any one of claims 1 to 5 into the pile hole. Pile can be built easily.

ADVANTAGE OF THE INVENTION According to this invention, the construction method of the assembly reinforcing bar which can arrange a reinforcing bar easily to the diameter-expanded part of the bottom part of a pile hole, and a pile using the same can be provided.
As a result, it is possible to reliably increase the tip supporting force of the bottom enlarged-diameter pile and improve the reliability of the bottom enlarged pile.

< First Reference Form >
A first reference embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted.

[Structure of assembled rebar 1]
First, the structure of the assembled reinforcing bar 1 will be described.
FIG. 1 is a perspective view showing an assembled reinforcing bar according to a first reference embodiment . FIG. 2 is a structural diagram showing the enlarged-diameter reinforcing bar of the assembled reinforcing bar according to the first reference embodiment . FIG. 3 is an enlarged perspective view showing a part of the enlarged diameter portion reinforcing bar, where (a) shows the structure on one end side and (b) shows the structure on the other end side.

As shown in FIG. 1, the assembly reinforcing bar 1 is a reinforcing bar arranged inside the pile hole H, and a narrow diameter mainly arranged in a narrow diameter part Ha that is a narrow part of the diameter (width) of the pile hole H. It is comprised from the part reinforcement 2 and the enlarged diameter part reinforcement 3 arrange | positioned at the enlarged diameter part Hb which is the part to which the diameter of the pile hole H was expanded.
Here, the pile hole H, for example, is constructed by excavating the ground with a constant diameter to construct the narrow-diameter portion Ha, and then, using a dedicated excavating device (diameter expanding device), the vicinity of the bottom thereof is expanded into a truncated cone shape. It is formed by constructing the enlarged diameter portion Hb by making the diameter.

  As shown in FIG. 1, the narrow-diameter rebar 2 is a rebar formed in a tubular shape as a whole by combining a plurality of rod-shaped main bars 21, 21... And a plurality of ring-shaped hoop bars 22, 22. is there. The main bars 21, 21... Are arranged in an annular shape around the center axis of the pile in a state where the axial direction thereof is parallel to the axial direction of the pile. Further, the plurality of hoop bars 22, 22... Are fitted on the outer circumferences of the main bars 21, 21,.

  As shown in FIG. 1, the enlarged diameter part reinforcing bar 3 is a reinforcing bar arranged along the peripheral surface Hd of the enlarged diameter part Hb when the assembled reinforcing bar 1 is installed in the pile hole H, and the narrow diameter part reinforcing bar. 2 is a long member attached to the outer periphery near the lower end of 2 at substantially equal intervals. As shown in FIG. 2, the enlarged-diameter reinforcing bar 3 is mainly composed of two enlarged-diameter main bars 31, 31 arranged in parallel with each other, and a central portion (connection portion) of the two enlarged-diameter main bars 31. 33 and the middle of the roller portion 34 (see FIG. 2). The two enlarged diameter portion reinforcing bars 32 and 32 are arranged perpendicular to each other. Both end portions of the enlarged-diameter portion reinforcing bar 32 extend from the side of the enlarged-diameter main bar 31 so that a force acting in as wide a range as possible can be transmitted to the enlarged-diameter main bar 31. Further, the enlarged diameter portion distribution reinforcing bar 32 is curved along the outer peripheral surface of the narrow diameter portion reinforcing bar 2.

  One end side (upper end side) of the enlarged diameter portion reinforcing bar 3 is rotatably connected to the narrow diameter portion reinforcing bar 2 via the connecting portion 33. Specifically, as shown in FIG. 3A, the connecting portion 33 is fixed horizontally across the plate 33a and the plate 33a fixed across the two main reinforcing bars 21 and 21 of the narrow-diameter portion reinforcing bar 2. It is comprised from the hollow pipe 33b made and the rotating shaft 33c penetrated by the hollow part of the pipe 33b. And the enlarged diameter part reinforcement 3 can be rotated with respect to the narrow diameter part reinforcement 2 by attaching the upper end side of the enlarged diameter part main reinforcement 31 to the both ends of the rotating shaft 33c.

  As shown in FIG. 2, the other end side (lower end side) of the enlarged diameter portion reinforcing bar 3 protrudes by a length L from the lower end portion of the main reinforcement 21 of the narrow diameter portion reinforcing bar 2, and the assembly reinforcing bar 1 is lifted to pile. When it is lowered into the hole H, it comes into contact with the bottom surface Hc (see FIG. 1) of the pile hole H before the lower end of the narrow-diameter portion reinforcing bar 2.

  Moreover, the other end side of the enlarged diameter part reinforcement 3 is provided with the roller part 34 as shown in FIG.2 and FIG.3, and when it contact | abuts to the bottom face Hc of the pile hole H, the center axis | shaft of the pile hole H It is easy to slide in the direction away from the. Specifically, as shown in FIG. 3B, the roller portion 34 includes a cylindrical roller 34a and a shaft 34b. The roller 34a has a shaft hole 34c at the center thereof, and the shaft 34b can be inserted into the shaft hole 34c. Further, both end portions of the shaft 34 b are fixed to the lower end portion of the enlarged diameter portion main bar 31. Thereby, the roller 34a is rotatably fixed to the lower end part of the enlarged diameter main part 31 via the shaft 34b. The roller 34a is preferably formed to have a large diameter and a wide width so as to increase the ground contact area so that the roller 34a is not easily stabbed (slidable) with respect to the bottom surface Hc.

  Here, it is preferable to form the enlarged diameter portion main bar 31 in a dimension corresponding to the length of the peripheral surface Hd of the enlarged diameter portion Hb of the pile hole H. Moreover, the attachment position of the one end part of the enlarged diameter part reinforcement 31 with respect to the narrow diameter part reinforcement 2 is the diameter of the narrow diameter part Ha and the enlarged diameter when the lower end part of the narrow diameter part reinforcement 2 contacts the bottom face Hc of the pile hole H. It is preferable that the height position corresponds to the boundary with the portion Hb. If it does in this way, when the assembly reinforcement 1 is installed in the pile hole H, the surrounding surface Hd of the enlarged diameter part Hb and the enlarged diameter part reinforcement 3 become parallel, and it is suitable (refer FIG.4 (c)). In addition, it is more preferable to adjust the dimension of the enlarged diameter portion reinforcing bar 3 so that an appropriate concrete cover can be formed between the peripheral surface Hd of the enlarged diameter portion Hb and the enlarged diameter portion reinforcing bar 3.

[Pile construction method]
It continues and the construction method of a pile is explained.
FIG. 4 is a diagram showing the assembled reinforcing bars arranged in the pile holes over time, (a) before landing, (b) during deployment, (c) shows the state when installation is completed. It is.

(Pile hole construction process)
First, using a known excavator such as an earth drill, a pothole (narrow diameter portion Ha) having the same diameter is constructed in the ground. After constructing the narrow-diameter portion Ha, the enlarged-diameter portion Hb is constructed at the bottom of the narrow-diameter portion Ha using a dedicated device for enlarging the bottom of the narrow-diameter portion Ha. Thereby, the pile hole H whose bottom part was expanded in diameter is constructed. After excavation, it is preferable to inject muddy water or the like so that the hole wall does not collapse.

(Assembly rebar insertion process)
Next, the rebar 1 constructed as described above is lifted using a lifting machine such as a crane and inserted into the pile hole H. At this time, since the enlarged-diameter reinforcing bar 3 is configured to be rotatable, the assembled reinforcing bar 1 has the enlarged-diameter reinforcing bar 3 stretched along the narrow-diameter reinforcing bar 2 as shown in FIG. It will be in a state of attaching. Therefore, the diameter of the assembly reinforcing bar 1 is reduced, and the size of the pile hole H can be reduced.

  When the assembled reinforcing bar 1 is lowered toward the bottom surface Hc of the pile hole H, the lower end portion of the enlarged diameter portion reinforcing bar 3 protrudes from the lower end portion of the narrow diameter portion reinforcing bar 2. 2 will come into contact with the bottom surface Hc of the pile hole H before the lower end portion.

  Further, when the assembly reinforcing bar 1 is lowered, the enlarged diameter part reinforcing bar 3 is fixed to the narrow diameter part reinforcing bar 2 through the connection part 33 so as to be rotatable, and the narrow hole is formed at the center side of the pile hole H. Since the partial rebar 2 exists and restricts the movement, the lower end portion of the enlarged diameter portion reinforcing bar 3 is in the direction away from the narrow diameter portion reinforcing bar 2, as shown in FIG. The hole H moves in a direction approaching the peripheral surface Hd of the enlarged diameter portion Hb.

  And when the lower end part of the narrow diameter part reinforcement 2 contact | abuts to the bottom face Hc of the pile hole H, the movement of the enlarged diameter part reinforcement 3 stops. Thereby, as shown in FIG.4 (c), the enlarged diameter part reinforcing bar 3 will be arrange | positioned at the enlarged diameter part Hb of the pile hole H. FIG. In addition, it is suitable to adjust the dimension and attachment position of the enlarged diameter part reinforcing bar 3 so that it may be arranged along the peripheral surface Hd of the enlarged diameter part Hb.

(Concrete placing process)
Next, concrete is placed in the pile hole H in which the assembly reinforcing bars 1 are arranged. When the concrete is hardened and integrated with the assembly rebar 1, a pile having a bottom expanded in diameter is completed.

  Since the pile constructed in this manner has the narrow-diameter part reinforcing bar 2 and the enlarged-diameter part reinforcing bar 3 arranged so as to connect the narrow-diameter part Ha and the enlarged-diameter part Hb, it is applied to the concrete of the enlarged-diameter part Hb. The acting force can be reliably transmitted to the concrete of the narrow diameter portion Ha. Conversely, the force acting on the concrete of the narrow diameter portion Ha can be reliably transmitted to the concrete of the large diameter portion Hb. Therefore, the support force of the pile increased by the enlarged diameter part Hb can be utilized effectively.

  The best mode for carrying out the present invention has been described in detail with reference to the drawings. However, the present invention is not limited to the embodiment, and can be appropriately changed without departing from the gist thereof. is there.

FIG. 5 is a perspective view showing the other end of the enlarged-diameter reinforcing bar according to the modification of the first reference embodiment .
The configuration of the other end portion of the enlarged diameter portion reinforcing bar 3 is not limited to the configuration shown in FIG. 3B. For example, as shown in FIG. 5, gear-shaped rollers 134a and 134a and the rollers 134a, You may comprise from the bearing part 134b which connects 134a, and the shaft 134c penetrated by the hollow part of the said bearing part 134b. According to such a configuration, the protrusion of the gear-shaped roller 134a abuts on the bottom surface Hc of the pile hole H and rotates, so that the other end portion of the enlarged diameter portion reinforcing bar 3 is directed toward the peripheral surface Hd of the enlarged diameter portion Hb. Moving.

FIG. 6 is a structural diagram showing an assembled reinforcing bar according to a modification of the first reference embodiment .
The number of steps of the enlarged-diameter rebar 3 attached to the narrow-diameter rebar 2 is not limited to one (see FIG. 1), and includes, for example, two-stage enlarged-diameter rebars 3A and 3B as shown in FIG. You may comprise as follows. Furthermore, it is not restricted to 2 steps | paragraphs, You may make it provide the multistage expanded diameter part reinforcement 3 (illustration omitted). If it does in this way, the force which acts on the concrete with which the enlarged diameter part Hb was filled can be more efficiently transmitted to the narrow diameter part Ha.

  In addition, as shown in FIG. 6, the enlarged diameter part reinforcing bar 3B is arranged further inside the enlarged diameter part reinforcing bar 3A arranged along the peripheral surface Hd of the enlarged diameter part Hb. The full length is formed shorter than 3A, and the one end side is attached to the narrow diameter part reinforcing bar 2 below the enlarged diameter part reinforcing bar 3A. In addition, since the structure of the enlarged diameter part reinforcement 3A, 3B is substantially the same as the structure of the enlarged diameter part reinforcement 3 shown in FIG. 2, detailed description is abbreviate | omitted.

FIGS. 7A and 7B are structural views showing a diameter-enlarged portion reinforcing bar according to a modification of the first reference embodiment , where FIG. 7A is a front view and FIG. 7B is a side view.
The diameter-enlarged portion reinforcing bar 3C shown in FIG. 7 is provided with a fixing portion 31C on one end side (upper end side), and by the spacer S attached to the lower end portion of the main reinforcing bar 21, the angle α is set outward with respect to the vertical. The tilted point is different from the enlarged diameter portion reinforcing bar 3 shown in FIG.

  The enlarged portion main reinforcing bar 31 of the enlarged diameter portion reinforcing bar 3C is connected to the connecting portion 33 at a position spaced apart from the upper end thereof by a predetermined distance, and passes through the connecting portion 33 to the main reinforcing rod 21 of the narrow diameter portion reinforcing bar 2. It is fixed so that it can move. A portion extending upward from the connection position constitutes the fixing portion 31C. The fixing portion 31C is bent as shown in FIG. 7 (b) so as not to hinder the rotation of the enlarged diameter portion reinforcing bar 3C, and is arranged inside the hoop reinforcement 22, that is, in the hollow portion of the narrow diameter portion reinforcing bar 2. Has been. If the hoop line 22 does not exist at a position where the fixing unit 31C comes into contact, the fixing unit 31C may not be bent.

  A spacer S made of L-shaped steel is attached to the lower end portion of the narrow-diameter portion reinforcing bar 2. The enlarged diameter portion reinforcing bar 3C is inclined outward by α ° with respect to the vertical by the spacer S. Therefore, when the roller part 34 of the enlarged diameter part reinforcing bar 3C comes into contact with the bottom surface Hc of the pile hole H, the enlarged diameter part reinforcing bar 3C is easily moved in a direction away from the center of the pile hole H. Therefore, the enlarged diameter part reinforcing bar 3C can be arranged very easily in the enlarged diameter part Hb of the pile hole H.

In the first reference embodiment , the connecting portion 33 of the enlarged diameter portion reinforcing bar 3 is configured as shown in FIG. 3A, but the enlarged diameter portion reinforcing bar 3 is connected to the narrow diameter portion reinforcing bar 2 so as to be rotatable. As long as it is possible, it is not limited to such a configuration. For example, it may be configured in a hinge-like structure.

In the first reference embodiment , the enlarged-diameter reinforcing bar 3 is composed of two enlarged-diameter main bars 31. However, the present invention is not limited to this, and the enlarged-diameter reinforcing bar 3 is composed of one enlarged-diameter main bar. You may make it comprise.

In the first reference embodiment , the roller portion 34 is provided on the other end side (lower end portion) of the enlarged diameter portion reinforcing bar 3. For example, by forming the lower end of the enlarged diameter portion main reinforcement 31 in a J shape, You may make it easy to slide with respect to the bottom face Hc of the pile hole H. FIG.

In the first reference embodiment , the shape of the enlarged diameter portion Hb is a truncated cone shape. However, the shape is not limited to this. For example, the enlarged diameter portion Hb may be formed in a cylindrical shape having a larger diameter than the narrow diameter portion Ha. Good.

Moreover, in 1st reference form , although the pile hole H was circular and the shape of the narrow diameter part reinforcement 2 was made into the cylindrical shape, it is not restricted to this, For example, the continuous underground wall where the lower end part was expanded is used. It may be applied when building. In such a case, the pile hole may be formed in a flat rectangular shape, or the narrow-diameter portion reinforcing bar may be formed in a rectangular bowl shape. Moreover, you may make it attach an enlarged diameter part reinforcement only to one side of a narrow diameter part reinforcement. In addition, in this specification, a continuous underground wall shall also be contained in a kind of pile (clay pile).

< Second Reference Form >
Next, the assembled reinforcing bar according to the second embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted.
FIG. 8 is a perspective view showing an assembled reinforcing bar according to the second reference embodiment . FIG. 9 is an enlarged view of the enlarged-diameter portion reinforcing bar of the assembled reinforcing bar according to the second reference embodiment , where (a) is a front view and (b) is a side view. FIG. 10 is a front view showing a reinforcing member of the assembled reinforcing bar according to the second reference embodiment . FIG. 11 is a drawing showing a state in which the assembly rebar according to the second reference embodiment is inserted into a pile hole, (a) is a view showing a state before the slide member contacts the bottom of the pile hole, (B) is the figure which showed the state which installation of the assembly reinforcement was completed. FIG. 12 is a plan view showing a developed state of the assembled reinforcing bar according to the second reference embodiment .

[Structure of assembled rebar 10]
Assembly rebar 10 according to the second referential embodiment, as shown in FIG. 8, by the connecting member 5 and the sliding member 4 to be described later, that is configured as push the enlarged diameter portion reinforcing bars 3, the first reference mentioned above It is different from the form .
Specifically, as shown in FIG. 8, the assembled rebar 10 is located at a position spaced upward from the lower end of the narrow-diameter rebar 2 disposed in the narrow-diameter portion Ha of the pile hole H and the lower-diameter rebar 2. A plurality of enlarged-diameter rebars 3 that are rotatably connected and a slide that is arranged so as to protrude from the lower end of the narrow-diameter rebar 2 before the assembly rebar 10 contacts the bottom surface Hc of the pile hole H. A member 4 (see FIG. 11A) and a connecting member 5 having one end side rotatably connected to the enlarged diameter portion reinforcing bar 3 and the other end side rotatably connected to the slide member 4. Yes.
Here, since the structure of the narrow-diameter portion reinforcing bar 2 has a configuration substantially similar to that of the first reference embodiment described above, a duplicate description is omitted.

As shown in FIGS. 8 and 9, the enlarged diameter portion reinforcing bar 3 is formed by bending one enlarged diameter portion main reinforcement 31 into a substantially U shape. As shown in FIG. 9A, the enlarged diameter portion main bar 31 is substantially parallel from one end side (upper side of FIG. 9A) to the intermediate portion, and the other end side of the intermediate portion (FIG. 9). They are formed so as to be separated from each other toward the lower side of (a).
As in the first reference embodiment , a connecting portion 33 is provided on one end side of the enlarged-diameter rebar 3 and is rotated upward from the lower end of the main rebar 21 of the narrow-diameter portion rebar 2 at a predetermined interval. It is mounted movably. Further, as shown in FIG. 9B, the end portion on one end side of the enlarged diameter portion reinforcing bar 3 is bent into a J shape, and a fixing portion 31C is formed. As shown in FIG. 12, the fixing portion 31 </ b> C is disposed inside the narrow-diameter portion reinforcing bar 2 when the large-diameter portion reinforcing bar 3 is deployed. Thereby, fixation with the concrete with which the inside of the narrow diameter part reinforcement 2 is filled and the enlarged diameter part reinforcement 3 is achieved. The length of the fixing unit 31C is preferably about 45 times the diameter of the reinforcing bar.
Further, in the second reference form , since the enlarged diameter portion reinforcing bar 3 is pushed up by the slide member 4 and the connecting member 5, the other end side of the enlarged diameter portion reinforcing bar 3 needs to protrude from the lower end of the narrow diameter portion reinforcing bar 2. There is no. In the state where the assembly reinforcing bar 10 is installed in the pile hole H, the enlarged diameter portion reinforcing bar 3 is arranged substantially horizontally by rotating the other end side in the radially outward direction.

The slide member 4 is a member that plays a role of pushing up (pushing out) the enlarged diameter portion reinforcing bar 3 via the connecting member 5 by sliding upward relative to the narrow diameter portion reinforcing bar 2. As shown in FIGS. 8 and 11, the slide member 4 has a plurality of rod-shaped reinforcing bars 41 arranged vertically in an annular shape, and a ring-shaped hoop bar 42 is fitted on the outside thereof to form a cylindrical shape as a whole. It is a formed member. In the second reference embodiment , the slide member 4 is formed to have a smaller diameter than the narrow-diameter portion reinforcing bar 2 and is disposed concentrically inside the narrow-diameter portion reinforcing bar 2. The slide member 4 is connected to the narrow-diameter part reinforcing bar 2 via a plurality of connecting members 5 and a plurality of enlarged-diameter part reinforcing bars 3.

Thereby, as shown in FIG. 11A, the slide member 4 is in a state before the assembly rebar 10 lands on the bottom surface Hc of the pile hole H (hereinafter, may be referred to as “before installation is completed”). It will be in the state suspended by the narrow diameter part reinforcement 2 via the enlarged diameter part reinforcement 3 and the connection member 5. FIG. At this time, the lower end portion of the slide member 4 protrudes from the lower end portions of the narrow-diameter portion reinforcing bar 2 and the enlarged-diameter portion reinforcing bar 3. Moreover, since the slide member 4 plays the role of a weight, the enlarged diameter portion reinforcing bar 3 does not spread while the assembly reinforcing bar 10 is being inserted into the pile hole H.
In addition, in the 2nd reference form , although the slide member 4 was comprised with the steel rod, it is not restricted to this, You may comprise using another member (for example, steel pipe etc.).

  As shown in FIGS. 8 and 9, the connecting member 5 is a member that connects the enlarged diameter portion reinforcing bar 3 and the slide member 4, and in the present embodiment, is constituted by two bar-shaped reinforcing bars arranged in parallel. ing. As shown in FIG. 9, a connecting portion 51 including a pipe 51a and a rotating shaft 51b is provided on one end side of the connecting member 5. The connecting member 5 is attached to the pipe 51a, and both ends of the rotating shaft 51b inserted through the hollow portion of the pipe 51a are attached to the enlarged-diameter main bar 31 so that the connecting member 5 can be rotated to the enlarged-diameter reinforcing bar 3. It is connected to. Although not shown, a connecting portion 52 (see FIG. 11) having the same structure is provided on the other end side of the connecting member 5 and is connected to the slide member 4 so as to be rotatable. . Therefore, the connecting member 5 can be rotated so as to push up the enlarged diameter portion reinforcing bar 3 as the narrow diameter portion reinforcing bar 2 descends with respect to the slide member 4 landing on the bottom surface Hc of the pile hole H. Yes.

As shown in FIG. 9, the connecting member 5 is in a state before the slide member 4 contacts the bottom surface Hc of the pile hole H (see FIG. 11 (a)). That is, it is connected to a position spaced downward from the connection position with the narrow-diameter portion reinforcing bar 2. Further, the distance between the connecting portion 33 and the connecting portion 51, the length of the connecting member 5, and the protrusion amount L1 of the slide member 4 (see FIG. It is preferable to set the diameter of the enlarged diameter portion reinforcing bar 3 so as to be substantially horizontal when landing. Moreover, in the 2nd reference form , although the connection member 5 was comprised with the steel rod, it is not restricted to this, For example, you may comprise with steel materials, such as L-shaped steel and a channel steel.

The reinforcing member 6 is a member that connects and reinforces adjacent enlarged-diameter rebars 3. As shown in FIG. 10, one end portions 61 b and 62 b of the two rod-shaped members 61 and 62 are pin-joined. Configured. The other end portions 61a and 62a of the two rod-shaped members 61 and 62 are respectively pin-bonded to the distal end portion of the enlarged diameter portion reinforcing bar 3 via the plate 31a.
Thereby, the reinforcing member 6 is folded as shown in FIG. 10 in a state where the enlarged diameter reinforcing bar 3 is not spread, that is, in a state where the assembled reinforcing bar 10 is not landed on the bottom surface Hc of the pile hole H. It has become. And the angle (alpha) which the rod-shaped members 61 and 62 comprise becomes large as the diameter expansion part reinforcement 3 expand | deploys. Furthermore, when the installation of the assembled reinforcing bars 10 is completed and the enlarged diameter portion reinforcing bars 3 are radially expanded, the reinforcing member 6 is in a straight line state as shown in FIG. Thereby, the front-end | tip part of the enlarged diameter part reinforcement 3 will be connected cyclically | annularly, and the support force of a pile can be improved further. The same applies to the reinforcing member 6 connected to the intermediate portion of the enlarged diameter portion reinforcing bar 3.

In the second reference embodiment , the reinforcing members 6 are provided at two positions, that is, the distal end portion and the intermediate portion of the enlarged-diameter portion reinforcing bar 3. However, the present invention is not limited to this. It may be more than one place. In the second reference embodiment , the two rod-shaped members 61 and 62 are formed by pin joining, but a larger number of rod-shaped members may be formed by pin joining. Further, in the second reference embodiment , the rod-shaped member is connected to be rotatable, but is not limited thereto, and may be formed of a wire having a predetermined strength. Even in such a case, the expanded-diameter rebar 3 can be annularly connected in the expanded state while expanding from the folded state to the straight line state following the expansion of the expanded-diameter portion reinforcing bar 3.

As shown in FIGS. 8 and 11, the pile hole H in which the assembled reinforcing bar 10 according to the second reference form is installed has the side surface of the enlarged diameter part Hb formed substantially perpendicularly to the first reference form . Is different. And, in the portion where the narrow diameter portion Ha and the wide diameter portion Hb are continuous, the overexcavated portion He is chamfered in a taper shape, so that the earth and sand of this portion collapses and does not hinder the development of the assembled rebar 10. It has become. In addition, it is suitable to design the concrete filled in the excavation part He ignoring in structural calculation.
Here, the height D1 (see FIG. 11B) of the vertical side surface of the enlarged diameter portion Hb is preferably about 1000 mm, for example, although it depends on the pile diameter. The difference D2 between the reinforcing bar 3 and the upper end of the vertical side surface is preferably about 200 mm.

[Pile construction method]
Next, with reference to FIG. 11, a method for constructing a pile using the assembled reinforcing bars 10 will be described.

(Pile hole construction process)
First, using a known excavator such as an earth drill, a pothole (narrow diameter portion Ha) having the same diameter is constructed in the ground. After constructing the narrow-diameter portion Ha, the enlarged-diameter portion Hb is constructed at the bottom of the narrow-diameter portion Ha using a dedicated device for enlarging the bottom of the narrow-diameter portion Ha. At this time, a portion where the narrow-diameter portion Ha and the wide-diameter portion Hb are continuous is excavated in a tapered shape to form the overexcavated portion He. Thereby, the pile hole H whose bottom part was expanded in diameter is constructed. After excavation, it is preferable to inject muddy water or the like so that the hole wall does not collapse.

(Assembly rebar insertion process)
Next, the assembled rebar 10 configured as described above is lifted using a lifting machine such as a crane and inserted into the pile hole H. At this time, since the enlarged diameter portion reinforcing bar 3 and the connecting member 5 are rotatably connected to the narrow diameter portion reinforcing bar 2 and the slide member 4, the assembled reinforcing bar 10 is as shown in FIG. In addition, the enlarged diameter portion reinforcing bar 3 is stuck along the narrow diameter portion reinforcing bar 2. Therefore, the diameter of the assembled reinforcing bar 10 is reduced, and the size of the pile hole H can be reduced. Further, as shown in FIG. 11A, the slide member 4 hangs from the narrow-diameter part reinforcing bar 2 via the enlarged-diameter part reinforcing bar 3 and the connecting member 5, and the narrow-diameter part reinforcing bar 2 and the enlarged-diameter part reinforcing bar 3. It will be in the state which protruded from the lower end of.

  When the assembled rebar 10 is lowered in this state, the slide member 4 protrudes from the lower ends of the narrow-diameter portion rebar 2 and the enlarged-diameter portion rebar 3, so that the lower end portion of the slide member 4 is the narrow-diameter portion rebar 2 and It will contact | abut to the bottom face Hc ahead of the enlarged diameter part reinforcement 3.

  Further, when the assembled reinforcing bar 10 is lowered, the slide member 4 and the connecting member 5, the connecting member 5 and the enlarged diameter part reinforcing bar 3, and the enlarged diameter part reinforcing bar 3 and the narrow diameter part reinforcing bar 2 can rotate with respect to each other. 11 (b), the enlarged-diameter reinforcing bar 3 rotates around the connecting portion 33 as the distance between the connecting portion 33 and the connecting portion 52 approaches. And rotation of the enlarged diameter part reinforcement 3 is complete | finished when the lower end part of the narrow diameter part reinforcement 2 contact | abuts to the bottom face Hc. At this time, the enlarged-diameter rebar 3 is separated from the bottom surface Hc of the pile hole H and is in a substantially horizontal state, and is expanded radially as shown in FIG.

  Further, as the plurality of enlarged-diameter rebars 3, 3... Expand radially, the reinforcing member 6 connected between the adjacent enlarged-diameter reinforcing bars 3 is straight from the folded state (see FIG. 10). (See FIG. 12). Thereby, the enlarged diameter part reinforcement 3 will be connected cyclically | annularly and the support force of a pile will improve.

(Concrete placing process)
Next, concrete is placed in the pile hole H in which the assembled reinforcing bars 10 are arranged (not shown). When the concrete is hardened and integrated with the assembled rebar 10, a pile with a bottom expanded in diameter is completed.

Since the pile constructed in this manner has the narrow-diameter part reinforcing bar 2 and the enlarged-diameter part reinforcing bar 3 arranged so as to connect the narrow-diameter part Ha and the enlarged-diameter part Hb, it is applied to the concrete of the enlarged-diameter part Hb. The acting force can be reliably transmitted to the concrete of the narrow diameter portion Ha. Conversely, the force acting on the concrete of the narrow diameter portion Ha can be reliably transmitted to the concrete of the large diameter portion Hb. Therefore, the support force of the pile increased by the enlarged diameter part Hb can be utilized effectively.
Moreover, according to the assembly reinforcing bar 10 which concerns on a 2nd reference form , since the enlarged diameter part reinforcing bar 3 can be expand | deployed in a substantially horizontal state, the burden of a cross-sectional force larger than a 1st reference form becomes possible, and structurally Is advantageous. Therefore, a larger supporting force can be obtained with the same size pile. In other words, an equivalent supporting force can be obtained with a pile having a smaller structural dimension.

The second reference embodiment for carrying out the present invention has been described in detail with reference to the drawings. However, the present invention is not limited to this, and can be appropriately changed without departing from the gist of the present invention. .

For example, in the second reference embodiment , the enlarged-diameter rebar 3 is formed in a substantially U shape, but is not limited to this, and is configured by a straight (I-shaped) rebar as shown in FIG. May be. According to this structure, the enlarged diameter part reinforcement 3 can be correctly arrange | positioned radially at the enlarged diameter part Hb of the pile hole H. FIG.

In the second reference embodiment , the fixing portion 31C is formed in a J shape. However, the shape is not limited to this shape as long as a predetermined fixing length can be obtained.

Moreover, in the 2nd reference form, although it comprised so that the edge part of the other end side of the enlarged diameter part reinforcement 3 may be located above the lower end part of the narrow diameter part reinforcement 2, it is not restricted to this. For example, the end portion on the other end side of the enlarged diameter portion reinforcing bar 3 may protrude below the lower end portion of the narrow diameter portion reinforcing bar 2.

In the second reference embodiment , the fixing portion 31C is positioned above the connecting portion 33 between the enlarged diameter portion reinforcing bar 3 and the narrow diameter portion reinforcing bar 2 in a state before the assembly reinforcing bar contacts the bottom surface of the pile hole. However, the present invention is not limited to this. As shown in FIG. 14, the fixing portion 31 </ b> C is located below the connection portion 33 between the enlarged diameter portion reinforcing bar 3 and the narrow diameter portion reinforcing bar 2. May be.

FIG. 14 is a view showing a state where the assembly reinforcing bar according to the present embodiment is inserted into a pile hole, and (a) is a view showing a state before the slide member comes into contact with the bottom surface of the pile hole. b) is a diagram showing a state in which the installation of the assembled reinforcing bars has been completed.
As shown in FIG. 14A, the assembled reinforcing bar 20 according to the present embodiment has the fixing portion 31 </ b> C positioned below the connecting portion 33 in a state before the assembled reinforcing bar 20 contacts the bottom surface Hc of the pile hole H. The one end side of the connecting member 5 is rotatably connected to the fixing portion 31C. The other end side of the connecting member 5 is rotatably connected to the slide member 4.

  14B, when the assembly reinforcing bar 20 is lowered into the pile hole H, the slide member 4 first contacts the bottom surface Hc of the pile hole H. When the assembled reinforcing bar 20 is further lowered, the slide member 4 slides relatively upward with respect to the narrow-diameter portion reinforcing bar 2, and the interval between the connecting portion 33 and the connecting portion 52 is narrowed. Therefore, the force pulling the enlarged diameter portion reinforcing bar 3 downward via the connecting member 5 is loosened, and the enlarged diameter portion reinforcing bar 3 is rotated in the direction of arrow A (outer diameter direction). Thereby, the enlarged diameter part reinforcement 3 will be arranged by the enlarged diameter part Hb of the pile hole H in a substantially horizontal state.

It is the perspective view which showed the assembly reinforcing bar which concerns on a 1st reference form . It is the structure figure which showed the enlarged diameter part reinforcement of the assembly reinforcement which concerns on 1st reference form . It is the perspective view which expanded and showed a part of enlarged diameter part reinforcement, (a) is the figure which showed the structure of the one end side, (b) respectively showed the structure of the other end side. It is the figure which showed the assembly reinforcing bar arrange | positioned at a pile hole with time, (a) is before landing, (b) is during expansion | deployment, (c) is the figure which showed the state at the time of completion of installation, respectively. It is the perspective view which showed the other end part of the enlarged diameter part reinforcing bar which concerns on the modification of 1st reference form . It is the structure figure which showed the assembly reinforcing bar which concerns on the modification of 1st reference form . It is the structure figure which showed the enlarged diameter part reinforcing bar which concerns on the modification of 1st reference form , (a) is a front view, (b) is a side view. It is the perspective view which showed the assembly reinforcing bar which concerns on a 2nd reference form . It is the figure which expanded and showed the enlarged diameter part reinforcement of the assembly reinforcing bar which concerns on a 2nd reference form , (a) is a front view, (b) is a side view. It is the front view which showed the reinforcement member of the assembly reinforcing bar which concerns on a 2nd reference form . It is drawing which showed the state which inserted the assembly reinforcing bar which concerns on a 2nd reference form in the pile hole, (a) is the figure which showed the state before a slide member contacts the bottom face of a pile hole, (b) It is the figure which showed the state which installation of the assembly reinforcement was completed. It is the top view which showed the expansion | deployment state of the assembly reinforcing bar which concerns on a 2nd reference form . It is the top view which showed the expansion | deployment state of the assembly reinforcing bar which concerns on this embodiment . It is drawing which showed the state which inserted the assembly reinforcing bar which concerns on this embodiment in the pile hole, (a) is the figure which showed the state before a slide member contacts the bottom face of a pile hole, (b) is assembly. It is the figure which showed the state which installation of the reinforcing bar was completed.

1,10,20 Assembly Rebar 2 Narrow Diameter Rebar 3 Large Diameter Reinforcing Bar 31 Large Diameter Main Bar 32 Large Diameter Distribution Force 33 Connection Portion 34 Roller 4 Slide Member 5 Connecting Member 6 Reinforcement Member H Pile Hole Ha Narrow Diameter Part Hb Expanded part Hc Bottom

Claims (6)

An assembly rebar placed in a pile hole with an expanded bottom,
A narrow-diameter rebar disposed over the bottom of the pile hole from the narrow-diameter part of the pile hole ;
A plurality of enlarged-diameter rebars that are rotatably connected to a position spaced upward from the lower end of the narrow-diameter part reinforcing bars, and are arranged in the enlarged-diameter part of the pile hole ;
In a state before the small diameter reinforcing bars into contact with the bottom surface of Kuiana, the projects from the lower end of the small diameter rebar, a slide member slidably disposed relative to the small diameter rebar,
One end side is rotatably connected to the enlarged-diameter rebar, and the other end side is configured to include a connecting member rotatably connected to the slide member,
The enlarged-diameter reinforcing bar has a fixing portion located closer to the center of the pile hole than the narrow-diameter part reinforcing bar in a state where the narrow-diameter part reinforcing bar is in contact with the bottom surface of the pile hole,
The slide member is coupled to the fixing unit via the coupling member,
The plurality of enlarged-diameter reinforcing bars are rotated by the slide member so that the fixing portion is on the lower side before the slide member comes into contact with the bottom surface of the pile hole. The plurality of enlarged-diameter rebars rotate so as to open downward from above by being in contact with the bottom surface of the pile hole and approaching the narrow-diameter part reinforcing bars, and are arranged in the enlarged-diameter part. Assembly rebar characterized by   2. The assembly reinforcing bar according to claim 1, wherein the plurality of enlarged diameter portion reinforcing bars are arranged substantially horizontally with both the narrow diameter portion reinforcing bar and the slide member being in contact with the bottom surface of the pile hole. . Further comprising a reinforcing member that connects the adjacent enlarged-diameter rebars,
The reinforcing member is assembled rebar according to claim 1 or claim 2, characterized in that it is constituted foldably. The reinforcing member is composed of at least two rod-like members connected to each other so as to be rotatable.
The assembled reinforcing bar according to claim 3 , wherein both ends of the reinforcing member are rotatably connected to adjacent enlarged diameter portion reinforcing bars. The assembled reinforcing bar according to claim 3 , wherein the reinforcing member is made of a wire. A method for constructing a pile using the assembled reinforcing bar according to any one of claims 1 to 5 ,
Pile hole construction process for constructing a pile hole with an expanded bottom,
An assembly rebar insertion step of inserting the assembly rebar into the pile hole.

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