JP4713277B2 - Pile foundation reinforcement structure - Google Patents

Description

  The present invention relates to a pile foundation reinforcing structure for improving the horizontal and vertical resistance of a pile foundation structure.

The construction method which reinforces the existing pile is described in Unexamined-Japanese-Patent No. 2003-155752 (patent document 1) by this applicant. In this method, a reinforcing body formed by solidifying and improving the ground is provided in the underground portion in the depth direction of the existing pile.
As a conventional method for solidifying and improving the ground in this way, there is a high pressure injection method. The high-pressure injection method is a method of spraying hardened materials such as water, air and cement onto the ground at ultrahigh pressure, and creating solidified improved bodies by cutting ground, mixing hardened materials, and stirring. Since it becomes work, there exists a subject that construction cost becomes high.
In addition, as in Patent Document 1, when a sufficient horizontal resistance force and vertical resistance force are obtained by providing a reinforcement body in the depth direction underground part of the existing pile, the lengths of the reinforcement bodies in the depth direction are compared. There is a problem that the construction cost becomes high.

JP 2003-155752 A

  An object of the present invention is to make the length in the depth direction of the reinforcing body provided in the ground relatively small, and even if the reinforcing body is relatively small, sufficient horizontal resistance and vertical resistance are obtained. It is to provide a pile foundation reinforcement structure capable of obtaining force.

In the present invention, a footing for supporting the structure, a plurality of piles reaching the support layer from the footing , a depth direction underground part of the pile spaced apart from the structure and separated upward from the support layer the reinforcing member as the solidified body comprising a cement for connecting the piles each other in basic structure consisting of a plurality of increasing pile side ground of the footing, bulking and the upper end of the pile on the side of the footing, the bottom end A pile foundation reinforcing structure characterized in that is fixed to the reinforcing body is provided.

  In the above-mentioned pile foundation reinforcement structure, a reinforcement body is provided in the depth direction underground part of the foundation structure composed of the footing and a plurality of piles, and the reinforcement body and the footing are connected by a reinforcing material or an additional pile. This increases the rigidity of the entire foundation structure. By increasing the rigidity of the entire foundation structure in this way, the length of the reinforcing body in the depth direction can be made relatively small, and in that case, sufficient horizontal resistance force and vertical resistance force can be obtained. .

  The pile foundation reinforcing structure of the present invention has a relatively large size of the reinforcing body, that is, the length in the depth direction of the ground, as compared with Patent Document 1 in which only the reinforcing body is provided in the depth direction underground portion of the pile. It becomes possible to make it small, and it becomes possible to significantly reduce the cost. Further, even when the reinforcing body is formed to be relatively small, it is possible to obtain a sufficient horizontal resistance force and vertical resistance force.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 is a cross-sectional view of a pile foundation reinforcing structure 10 according to the present invention. In FIG. 1, the pier 11 as a ground structure has a footing 13 on the ground 12, and a plurality of piles 15 are provided in the ground 12 so as to reach the support layer 14 from the footing 13. With respect to such a pile foundation, the pile foundation reinforcement structure 10 according to the present invention is provided with a reinforcing body 16 in the depth direction underground portion of the pile 15 separated from the footing 13 as shown in FIG. A reinforcing material 17 such as a lock bolt or an anchor extends from the predetermined position 13 to the reinforcing body 16 in the ground, and the footing 13 and the reinforcing body 16 are connected.
In the pile foundation reinforcement structure 10, the footing 13 and the reinforcement body 16 are connected by the plurality of reinforcement members 17 as described above, and the rigidity L of the reinforcement body 16 is increased by increasing the rigidity of the foundation structure as a whole. In this case, sufficient horizontal resistance force and vertical resistance force can be obtained.

Here, the reinforcing body 16 is constructed from a hardened material containing cement so as to connect the plurality of piles 15 to each other, and can be constructed by, for example, a conventional high-pressure injection method. Although not shown in the drawings, this high-pressure injection method uses a pipe body that is provided with a nozzle at its tip that can eject a hardened material such as water, air, and cement toward the ground at an ultrahigh pressure. To a predetermined depth in the ground, and by this, ground solid cutting, hardening material mixing and stirring are carried out to create a solidified improved body in the ground. It is possible to form the reinforcing body 16 by forming a plurality of columnar solidified improvement bodies at a predetermined depth in the ground at a predetermined length by connecting them within a predetermined range in the ground by a high pressure injection method.
The reinforcing body 16 is provided in the depth direction underground part of the pile 15 spaced apart from the footing 13 and spaced upward from the support layer 14, and more specifically, piles against horizontal loads such as earthquakes. The position at which the stress generated in is the smallest is determined as appropriate.
Moreover, the cross-sectional shape of the reinforcing body 16 in the horizontal direction can take several forms as illustrated in FIGS. 2 (a) to 2 (c). FIG. 2 (a) shows that the reinforcing body 16a is formed over the entire predetermined range by the high-pressure injection method, and in FIG. 2 (b), the reinforcing body 16b is formed leaving the original ground 18 in the center of the predetermined range. In FIG. 2C, the base ground 18 is left wider than in FIG. 2B, and the reinforcing body 16c is formed in an annular shape.

Next, FIGS. 3A and 3B are plan views looking down along the line III-III in FIG. 1, respectively, illustrating the relative arrangement of the reinforcing material 17 with respect to the footing 13.
The reinforcing member 17 can be obliquely driven from the side ground of the footing 13 to the reinforcing body 16 and the upper end thereof can be fixed to the side surface of the footing 13 with a fixing member 19 as shown in FIG. is there. Alternatively, the reinforcing member 17 has a through-hole formed in the footing 13, and the reinforcing member 17 is obliquely driven from here to the reinforcing member 16, and the upper end thereof is placed on the footing 13 as shown in FIG. Fixing can be performed by the fixing member 19. The reinforcing member 17 is not limited to installation in an oblique direction, and may be extended vertically downward from the positions of FIGS. 3 (a) and 3 (b), for example.

FIG. 4 is a cross-sectional view of a pile foundation reinforcing structure 20 having a form different from that of FIG.
In FIG. 4, a reinforcing body 16 is provided in the depth direction underground portion of the pile 15 separated from the footing 13 with respect to the existing pile foundation similar to FIG. 1, and the reinforcing body 16 is provided from a plurality of locations on the outer peripheral ground of the footing 13. An additional pile 21 extending to the top is provided, the upper end of the additional pile 21 is fixed to the side surface of the footing with concrete 22 or the like, and the lower end is embedded in the reinforcing body 16 and fixed integrally.
In addition, the reinforcement body 16 can be formed similarly to what was illustrated by FIG.1 and FIG.3.
In the pile foundation reinforcement structure 20, the footing 13 and the reinforcement body 16 are connected by a plurality of additional piles 21, and the rigidity L of the reinforcement body 16 is relatively reduced by increasing the rigidity of the foundation structure as a whole. In this case as well, sufficient horizontal resistance force and vertical resistance force can be obtained.

It is sectional drawing of the pile foundation reinforcement structure concerning this invention. (A)-(c) is sectional drawing of the position corresponding to the II-II line | wire of FIG. (A) and (b) are the top views looked down along the III-III line of FIG. It is sectional drawing of the pile foundation reinforcement structure of a form different from FIG.

Explanation of symbols

10 Pile foundation reinforcement structure 11 Pier (structure)
12 Ground 13 Footing 15 Plural piles 16 Reinforcement body 17 Reinforcement material 20 Pile foundation reinforcement structure 21 Additional pile

Claims (1)

A footing for supporting the structure , a plurality of piles reaching the support layer from the footing , and a pile between the piles spaced downward from the structure and spaced upward from the support layer. In the basic structure consisting of a reinforcing body as a solidified body containing cement to be connected ,
The footing a plurality of increasing pile laterally ground of bulking and the upper end side of footing piles, lower end pile foundation reinforcement structure, characterized in that the fixing to the reinforcing member.

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