Pile head cap, pile head structure, pile foundation structure and construction method thereof

Abstract

To provide a pile head cap, a pile head structure, a pile foundation structure and its construction method, capable of easily and accurately positioning a member for joining a pile head side of a tubular pile and a footing of a foundation in a proper position of the tubular pile.SOLUTION: A pile-head cap 1 is mounted on the pile-head side 8a of a steel-pipe pile 8 buried into the ground G. The pile-head cap 1 includes a plate portion 11 that covers a pile-head 8a, a positioning engagement portion 12 that engages with an outer peripheral side or an inner peripheral side of the pile-head 8a to position the plate portion 11, an inner-pipe mounting hole 13 that is formed in the plate portion 11 and through which an inner pipe 2 (a member for coupling a pile-head side of the steel-pipe pile 8 and a footing 9 of a base) passing through a center side of the plate portion 11 in a length direction of the steel-pipe pile 8 passes, and an air vent hole 14 formed in the plate portion 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pile head cap attached to the head of a tubular pile buried in the ground, a pile head structure, a pile foundation structure, and a construction method thereof. [Background technology]

[0002] Patent Document 1 discloses a footing-to-pile connection structure in which a footing and a pile head placed below the footing and filled with filler material are connected via one or more connecting members, wherein the connecting members have a plurality of shear stoppers on their outer peripheral surfaces, the upper end of the connecting member provided with the shear stoppers is embedded in the footing, and the lower end of the connecting member provided with the shear stoppers is embedded in the filler material of the pile head, making the connection between the footing and the pile a semi-rigid connection, and a buffer material is inserted at least either between the upper end surface of the connecting member and the footing, or between the lower end surface of the connecting member and the filler material of the pile head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4595545 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, there is no means for fixing the position of the connecting member, so the position of the connecting member must be adjusted vertically and horizontally during construction while pouring the filler, which is a drawback as it requires a lot of work. Also, such position adjustment has the drawback of lowering the accuracy of positioning the connecting member.

[0005] The present invention aims to provide a pile head cap, a pile head structure, a pile foundation structure, and a construction method thereof that can easily and accurately position a member for connecting the pile head side of a tubular pile to the footing of a foundation at an appropriate position on the tubular pile. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the pile head cap of this invention is a pile head cap that is attached to the pile head of a tubular pile buried in the ground, and is characterized by having a plate portion that covers the pile head, a positioning engagement portion that engages with the outer or inner side of the pile head of the tubular pile to position the plate portion, an inner tube attachment hole formed in the plate portion through which an inner tube that penetrates the center side of the plate portion in the lengthwise direction of the tubular pile passes, and an air vent hole formed in the plate portion.

[0007] With the above configuration, the plate portion is positioned and arranged at the appropriate position of the head of the tubular pile by the positioning engagement portion, and the inner pipe attachment hole located on the center side of the plate portion allows the inner pipe to be easily and accurately arranged at the appropriate position of the tubular pile. In addition, since the plate portion is formed with air vent holes, it is possible to smoothly fill the inner pipe and the head of the tubular pile with filler material.

[0008] The pile head structure of the present invention is also a pile head structure equipped with the above-mentioned pile head cap, characterized in that the inner pipe is attached to the inner pipe attachment hole.

[0009] In the pile head structure, the inner pipe may have a plurality of recesses that extend into the inside of the inner pipe, thereby increasing resistance to the inner pipe being pulled out of the pile head.

[0010] An outer enclosure pipe may be located above the pile cap at a distance from the inner pipe, surrounding the inner pipe, and a bottom plate located below the outer enclosure pipe may be attached to the inner pipe. This allows the outer enclosure pipe to be filled with filler material.

[0011] In the pile head structure, the outer pipe may be provided with a reinforcing bar that protrudes upward beyond the height of the outer pipe, thereby making it easier to increase the bonding strength between the outer pipe and the footing of the foundation.

[0012] In the pile head structure, a filler may be precast inside the outer pipe and outside the inner pipe, which eliminates the need to fill the outer pipe with filler on-site, thereby reducing the amount of filler required on-site and shortening the construction time.

[0013] Furthermore, the pile foundation structure of this invention is a pile foundation structure obtained by attaching the above-mentioned pile head structure to the pile head of a tubular pile buried in the ground, and is characterized in that a backing plate is fixed to the tubular pile at a position lower than the lower end of the inner pipe, and filler material is filled above the backing plate up to the position of the pile head cap and into the inner pipe to a height higher than the position of the pile head cap, and the upper side of the inner pipe is located within the footing of the foundation.

[0014] With the above-mentioned pile foundation structure, the filler is filled on the upper side of the support plate and at least the lower side of the inner pipe, resulting in a semi-rigid joint structure in which the upper side of the inner pipe is located within the footing of the foundation.

[0015] Furthermore, the pile foundation structure of this invention is a pile foundation structure obtained by attaching the above-mentioned pile head structure, wherein a backing plate is fixed to the tubular pile at a position lower than the lower end of the inner pipe, and filling material is filled above the backing plate up to the position of the pile head cap, and also filled into the inner pipe to about the height where the pile head cap is located, the upper side of the inner pipe and the outer enclosing pipe are located within the footing of the foundation, and the hardening material that constitutes the footing is present on the upper side of the inner pipe and within the outer enclosing pipe.

[0016] With the above-mentioned pile foundation structure, the filler is filled on the upper side of the support plate and the lower side of the inner pipe, resulting in a semi-rigid joint structure in which the upper side of the inner pipe and the outer enclosing pipe are positioned within the footing of the foundation without any filler.

[0017] Furthermore, the pile foundation structure of this invention is a pile foundation structure obtained by attaching the above-mentioned pile head structure to the pile head of a tubular pile buried in the ground, and is characterized in that a backing plate is fixed to the tubular pile at a position lower than the lower end of the inner pipe, and filler material is filled above the backing plate up to the position of the pile head cap, and is filled into almost the entire interior of the inner pipe and almost the entire interior of the outer enclosing pipe, and the upper side of the inner pipe and the outer enclosing pipe are located within the footing of the foundation.

[0018] With the above-mentioned pile foundation structure, the filler is filled into almost the entire inner pipe, the upper side of the support plate, and almost the entire inside of the outer enclosure pipe, resulting in a semi-rigid joint structure in which the upper side of the inner pipe and the outer enclosure pipe are located within the footing of the foundation.

[0019] In addition, the construction method for a pile foundation structure of this invention is characterized by including the steps of attaching the pile head structure to the pile head of the tubular pile, and pouring filler material from the upper end side of the inner pipe to supply the filler material to the space above the support plate of the tubular pile and to the inner pipe.

[0020] In addition, the construction method for a pile foundation structure of this invention is characterized by including the steps of attaching the pile head structure to the pile head of the tubular pile, and pouring filler material from the upper end side of the inner pipe to supply the filler material to the space above the support plate of the tubular pile and the lower side of the inner pipe.

[0021] In addition, the construction method of the pile foundation structure of this invention includes the steps of attaching the pile head structure to the pile head of the tubular pile, and pouring filler material from the upper side of the inner pipe to supply the filler material to the space above the support plate of the tubular pile and to almost the entire inner pipe, and is characterized in that if the inside of the enclosure outer pipe is not filled with the filler material, the filler material is poured into the enclosure outer pipe during on-site construction. [Effects of the Invention]

[0022] The present invention has the effect of enabling the inner pipe, which can connect the pile head side of the tubular pile with the footing side of the foundation, to be easily and accurately positioned at an appropriate position on the tubular pile. [Brief explanation of the drawings]

[0023] [Figure 1] 1A is an explanatory diagram of a plan view of the pile head cap of the embodiment, and FIG. 1B is an explanatory diagram showing the attachment of this pile head cap to a steel pipe pile. [Figure 2] FIG. 1 is an explanatory diagram showing a pile head structure according to an embodiment. [Figure 3] FIG. 1 is an explanatory diagram showing a pile foundation structure according to an embodiment. [Figure 4] FIG. 1 is an explanatory diagram showing a step of burying a steel pipe pile underground in a construction method for a pile foundation structure according to an embodiment. [Figure 5] FIG. 5 is an explanatory diagram showing a step of attaching a pile head structure to the pile head of the steel pipe pile as a post-step in the construction method of the pile foundation structure of FIG. 4. [Figure 6] FIG. 6 is an explanatory diagram showing a step of filling a filler material into the pile head, the inner pipe, and the outer pipe of the steel pipe pile as a post-step of the construction method of the pile foundation structure of FIG. 5. [Figure 7] FIG. 10 is an explanatory diagram showing a pile head structure according to another embodiment. [Figure 8] FIG. 10 is an explanatory diagram showing a pile head structure according to another embodiment. [Figure 9] FIG. 10 is an explanatory diagram showing a pile foundation structure according to another embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing a pile foundation structure according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. As shown in Figures 1(A) and 1(B), a pile head cap 1 according to the embodiment is attached to the upper end of a pile head 8a of a steel pipe pile 8 (tubular pile) buried underground G. The pile head cap 1 is made of, for example, a metal material and has a disk-shaped plate portion 11 that covers the upper end of the pile head 8a and a positioning engagement portion 12 that protrudes from the underside of the plate portion 11. The positioning engagement portion 12 is, for example, a flat round steel pipe welded to the underside of the plate portion 11, and engages with the outer periphery (or the inner periphery) of the pile head 8a of the steel pipe pile 8 to position the plate portion 11.

[0025] Furthermore, an inner pipe mounting hole 13 is formed at a central position of the plate portion 11 in the pile head cap 1, and a plurality of air vent holes 14 are formed at a position approximately midway between the outer edge of the plate portion 11 and the inner pipe mounting hole 13. In this embodiment, the inner pipe mounting hole 13 is a hole formed at the center of the plate portion 11, and the inner pipe 2 is inserted into this inner pipe mounting hole 13 in the length direction (driving direction) of the steel pipe pile 8.

[0026] As shown in FIG. 2, the pile head structure 100 of the embodiment includes a pile head cap 1, an inner pipe 2, and an outer surrounding pipe 3.

[0027] The inner pipe 2 is a member that connects the pile head 8a side of the steel pipe pile 8 with the footing 9 of the foundation, and is made of, for example, a cylindrical metal member, and is fixed by welding to the plate portion 11 at a predetermined position in the height direction of the inner pipe 2. The inner pipe 2 also has multiple recesses 2a that penetrate into the inside of the inner pipe 2. These recesses 2a are formed by pressing a member from the outer periphery of the inner pipe 2 to recess it, or by pressing a spatula against the rotating inner pipe 2 to perform a squeezing process, etc.

[0028] The outer enclosure pipe 3 is made of a cylindrical steel pipe material that surrounds the inner pipe 2 at a distance from the inner pipe 2, at a location above the plate portion 11 of the pile head cap 1, and can have the same diameter as the steel pipe pile 8. A bottom plate 31 is located below the outer enclosure pipe 3. This bottom plate 31 is welded to the outer periphery of the inner pipe 2 at a predetermined position.

[0029] As shown in FIG. 3 , a pile foundation structure 101 according to this embodiment is a structure using a pile head structure 100. In this pile foundation structure 101, a backing plate 81 is fixed to a steel pipe pile 8 at a position below the lower end of the inner pipe 2. A filler material 7 (grout material, polymer material, etc.) is filled into substantially the entire interior of the inner pipe 2, the upper side of the backing plate 81 (up to the upper end of the pile head 8 a), and substantially the entire interior of the outer enclosure pipe 3. Furthermore, the range from the middle to the upper side of the inner pipe 2 and the entire outer enclosure pipe 3 are located within the footing 9 of the foundation. In this embodiment, reinforcing bars 83 are arranged in multiple stages in an annular shape or spirally on the inner circumferential surface above the backing plate 81 of the steel pipe pile 8, and are fixed to the steel pipe pile 8 by welding or the like.

[0030] In an embodiment of the method for constructing a pile foundation structure 101, a process of burying a steel pipe pile 8 in the ground G is carried out, as shown in Fig. 4. In this embodiment, the steel pipe pile 8 has a tip used for burying the pile on the outer periphery of its upper end. Then, as shown in Fig. 5, a pile head structure 100 is lowered from above the steel pipe pile 8, and the pile head structure 100 is attached to the pile head 8a of the steel pipe pile 8.

[0031] Next, as shown in Figure 6, filler material 7 is poured into the upper side of the inner pipe 2. As the filler material 7 is poured, the space above the backing plate 81 of the steel pipe pile 8 and almost the entire inner pipe 2 are filled with filler material 7. When the poured filler material 7 reaches the pile head cap 1 located at the upper end of the steel pipe pile 8, the filler material 7 begins to leak out through the air vent holes 14 in the plate portion 11 of the pile head cap 1. However, by blocking the air vent holes 14 at this time, the filler material 7 can be allowed to reach the upper end of the inner pipe 2.

[0032] In this embodiment, since the filler 7 is not filled inside the outer enclosure pipe 3 at the manufacturing stage of the pile head structure 100, the filler 7 is poured into the outer enclosure pipe 3 on-site, and the filler 7 is filled inside the outer enclosure pipe 3. Both fillers 7 may be made of the same material, or may have different properties.

[0033] Then, as shown in Figure 3, the pile foundation structure 101 is created by burying the area from the middle to the upper part of the inner pipe 2 located above the plate portion 11 of the pile head cap 1 and the surrounding outer pipe 3 in the footing 9 of the foundation.

[0034] With the pile head cap 1 and pile head structure 100 described above, the positioning engagement portion 12 positions and arranges the plate portion 11 at an appropriate position on the pile head 8a of the steel pipe pile 8, and a structure can be easily and accurately obtained in which the inner pipe 2 located at the center of the plate portion 11 is positioned at an appropriate horizontal position with an appropriate vertical protruding height relative to the steel pipe pile 8. In addition, because the plate portion 11 has air vent holes 14, the filler material 7 can be smoothly filled into the inner pipe 2 and the pile head 8a of the steel pipe pile 8.

[0035] If the inner pipe 2 has a plurality of recesses 2a that penetrate into the inside of the inner pipe 2, it is possible to increase the resistance to the inner pipe 2 coming out of the pile head 8a. In addition, since the recesses 2a are not convex, the inner pipe 2 can be smoothly inserted into the inner pipe mounting hole 13.

[0036] When an outer surrounding pipe 3 is positioned on the outer surface of the inner pipe 2 located above the pile head cap 1 at a distance from the inner pipe 2, the structure can be such that the filling material 7 is also filled inside the outer surrounding pipe 3.

[0037] In the above-mentioned pile foundation structure 101, the filler material 7 is filled above the bottom plate 31 up to the position of the pile head cap 1, and is filled almost entirely within the inner pipe 2 and the outer enclosing pipe 3, resulting in a semi-rigid joint structure in which the upper side of the inner pipe 2 and the entire outer enclosing pipe 3 are located within the footing 9 of the foundation.

[0038] Furthermore, when grout is used as the filler 7, the compressive strength is higher than that of ordinary foundation concrete, resulting in higher structural performance. When a polymer material is used as the filler 7, the compressive strength is slightly lower than that of ordinary foundation concrete, and the rigidity is also lower, making it possible to further reduce the fixation level of the pile head. Furthermore, by using filler 7 with the same rigidity on the upper and lower outer peripheries of the inner pipe 2, it is possible to avoid to some extent the concentration of bending and shear stress. Depending on the performance requirements of the building, in addition to the pile head structure 100 shown in Figure 2, a pull-out type and a type without an outer surrounding pipe, as shown below, can be used to meet a wide range of design conditions.

[0039] As shown in Fig. 7, in the pile head structure 100, a plurality of reinforcing bars 32 that protrude upward beyond the height of the outer enclosure pipe 3 may be attached, for example, to the outer periphery of the outer enclosure pipe 3. This makes it easy to increase the bonding strength between the outer enclosure pipe 3 and the footing 9 of the foundation. Note that the reinforcing bars 32 can also be omitted by increasing the length of the inner pipe 2 with the recessed portion 2a.

[0040] As shown in Fig. 8, in the pile head structure 100, the filler material 7 may be precast inside the outer enclosure pipe 3 and outside the inner pipe 2. This eliminates the need to fill the outer enclosure pipe 3 with the filler material 7 on-site, thereby reducing the amount of filler material required on-site and shortening the on-site construction time.

[0041] The pile foundation structure 101 shown in Figure 9 can also be obtained by attaching a pile head structure 100 to the pile head 8a of a steel pipe pile 8. However, the filler material 7 is filled above the backing plate 81 up to the position of the pile head cap 1, and is also filled inside the inner pipe 2 to approximately the height of the pile head cap 1, and the upper side of the inner pipe 2 and the enclosing outer pipe 3 are located within the footing 9 of the foundation without the filler material 7, and the upper side of the inner pipe 2 and inside the enclosing outer pipe 3 contain the hardening material that constitutes the footing 9.

[0042] In the above-mentioned pile foundation structure 101, the upper side of the receiving plate 81 and the lower side of the inner pipe 2 are filled with filler material 7, and a semi-rigid joint structure is obtained in which the upper side of the inner pipe 2 and the outer enclosing pipe 3 are filled with the hardening material of the foundation footing 9.

[0043] 10, the pile head structure 100 and the pile foundation structure 101 may have a structure without the surrounding outer pipe 3. In this structure, the filler 7 may be filled above the backing plate 81 up to the position of the pile head cap 1, and may also be filled into the inner pipe 2 at a height equal to or higher than the position of the pile head cap 1.

[0044] In these structures, the inner pipe 2 may not have the recessed portions 2a. Alternatively, instead of the recessed portions 2a, holes may be formed in the peripheral wall surface of the inner pipe 2, and these holes may generate pull-out resistance. Alternatively, instead of the recessed portions 2a, protrusions may be provided. These protrusions may be formed, for example, at 90-degree intervals along the circumferential direction of the inner pipe 2. By forming notches at 90-degree intervals on the edge of the inner pipe mounting hole 13 through which the protrusions pass, the inner pipe 2 can be inserted into the inner pipe mounting hole 13. If a partial gap is formed between the inner pipe mounting hole 13 and the inner pipe 2 by the notches, this gap functions as an air vent hole, so it is possible not to form the air vent hole 14.

[0045] Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as the present invention or within an equivalent scope. [Explanation of symbols]

[0046] 1: Pile cap 2: Inner tube 2a: Depression 3: Enclosure outer tube 7: Filling material 8: Steel pipe pile 8a:Pile head 9: Footing 11: Plate part 12: Positioning engagement part 13:Inner tube mounting hole 14: Air vent hole 31: Bottom plate 32: Reinforcement 81: Receiving plate 83: Reinforced concrete 100: Pile cap structure 101: Pile foundation structure G: Underground

Claims

1. A pile head cap that is attached to the head of a tubular pile buried in the ground, characterized in that it has a plate portion that covers the pile head, a positioning engagement portion that engages with the outer or inner side of the pile head of the tubular pile to position the plate portion, an inner tube attachment hole formed in the plate portion through which an inner tube that penetrates the center side of the plate portion in the lengthwise direction of the tubular pile passes, and an air vent hole formed in the plate portion.

2. A pile head structure comprising the pile head cap according to claim 1, wherein the inner pipe is attached to the inner pipe attachment hole.

3. 3. The pile head structure according to claim 2, wherein the inner pipe has a plurality of recesses extending into the inner pipe.

4. 3. The pile head structure according to claim 2, wherein an outer surrounding pipe surrounding the inner pipe is located at a distance from the inner pipe at a position above the pile head cap, and a bottom plate located on the lower side of the outer surrounding pipe is attached to the inner pipe.

5. 5. The pile head structure according to claim 4, wherein a reinforcing bar is attached to the outer enclosure pipe so as to protrude upward beyond the height of the outer enclosure pipe.

6. 5. The pile head structure according to claim 4, wherein a filler material is precast inside the outer enclosure pipe and outside the inner pipe.

7. A pile foundation structure obtained by attaching the pile head structure described in claim 2 or claim 3 to the head of a tubular pile buried in the ground, wherein a backing plate is fixed to the tubular pile at a position lower than the lower end of the inner pipe, and filler is filled above the backing plate up to the position of the pile head cap and into the inner pipe to a height higher than the position of the pile head cap, and the upper side of the inner pipe is located within the footing of the foundation.

8. A pile foundation structure obtained by attaching the pile head structure according to claim 4 or claim 5 to the head of a tubular pile buried in the ground, wherein a backing plate is fixed to the tubular pile at a position lower than the lower end of the inner pipe, and filling material is filled above the backing plate up to the position of the pile head cap, and also filled into the inner pipe to about the height where the pile head cap is located, the upper side of the inner pipe and the enclosing outer pipe are located within the footing of the foundation, and the hardening material that constitutes the footing is present on the upper side of the inner pipe and within the enclosing outer pipe.

9. A pile foundation structure obtained by attaching the pile head structure described in any one of claims 4 to 6 to the pile head of a tubular pile buried in the ground, wherein a backing plate is fixed to the tubular pile at a position below the lower end of the inner pipe, and filler is filled above the backing plate up to the position of the pile head cap, and also fills almost the entire interior of the inner pipe and almost the entire interior of the enclosing outer pipe, and the upper side of the inner pipe and the enclosing outer pipe are located within the footing of the foundation.

10. 8. A construction method for constructing a pile foundation structure as described in claim 7, comprising the steps of: attaching the pile head structure to the pile head of the tubular pile; and pouring filler material from the upper end side of the inner pipe to supply the filler material to the space above the support plate of the tubular pile and to the inner pipe.

11. 9. A construction method for constructing a pile foundation structure as described in claim 8, comprising the steps of: attaching the pile head structure to the pile head of the tubular pile; and pouring filler material from the upper end side of the inner pipe to supply the filler material to the space above the backing plate of the tubular pile and to the lower side of the inner pipe.

12. 10. A construction method for constructing a pile foundation structure as described in claim 9, comprising the steps of: attaching the pile head structure to the pile head of the tubular pile; and pouring filler material from the upper side of the inner pipe to supply the filler material to the space above the support plate of the tubular pile and to almost the entire inner pipe, wherein if the inside of the enclosure outer pipe is not filled with the filler material, the filler material is poured into the enclosure outer pipe during on-site construction.

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