JP2000129696A - Pile foundation method and pile foundation constructed by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively perform reinforcement of horizontal receiving resistance by closing a circumference constructing footing by a sheet pile having large rigidity and connecting the sheet pile to the footing to be left as a part of a structure. SOLUTION: A reinforced concrete or steel-made sheet pile 50 having large rigidity is buried by surrounding a space constructing a footing 20 to close a footing structure part. A prescribed number of piles 10 are driven in the space closed by the sheet pile 50, and the footing 20 constituted by concrete is placed in contact with the head part of the pike 10. During placing the sheet pile 50 acts as a form for placing the footing 20, and the footing 20 and the sheet pile 50 are integrated with concrete by connecting a reinforcing bar constituting the sheet pile 50 and the footing 20. As the result, horizontal receiving resistance can be largely obtained by leaving the sheet pile 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pile foundation method for constructing a pile foundation for supporting, for example, a pier and the like, and a pile foundation constructed by this pile foundation method.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a general pile foundation. In the drawing, reference numeral 10 denotes a plurality of piles which are driven into the ground G or are driven into place. As the pile, a concrete pile called a concrete pile or the like or a steel pile called a steel pipe pile is generally used. The head 11 of the pile 10 is driven from the ground surface to a desired depth or cut at a desired depth. A footing 20 made of reinforced concrete is constructed on the upper part of the pile 10, and a pier 30, for example, to be supported on the upper part of the footing 20 is constructed. Here, a plurality of piles 10 and a footing 2 constructed on the
Point to 0 and call it the pile foundation.

[0003] A construction method for constructing this conventional pile foundation will be schematically described with reference to FIG. Conventionally, while driving the pile 10,
A sheet pile 40 made of steel or the like is driven into the periphery, and the periphery is closed with the sheet pile 40. The soil on the upper part of the pile 10 is removed in a state where the periphery is closed, and the footing 20 is cast (cast concrete) on the removed portion. In this case, a gap W is provided between the sheet pile 40 and the footing 20, and the gap W is used as a working space. The gap W is generally 50 to 70 cm
It is taken to the extent.

[0004]

Conventionally, a footing 20 is used.
Is completed, the sheet pile 40 is pulled out and removed.
When the sheet pile 40 is pulled out, there are disadvantages such as that the surrounding ground sinks and affects underground objects. Footing 20
There is also a drawback that the horizontal passive resistance is reduced because the ground around is soft.

For this reason, conventionally, for example, in order to increase the horizontal passive resistance during an earthquake, the diameter of the pile 10 is increased,
Although measures are taken such as increasing the number of these methods, there is a drawback that the cost increases when these measures are adopted. Furthermore, since the method of performing the work while securing the work space is adopted, there is a disadvantage that the plane shape of the deadline becomes large and the work in a narrow place becomes difficult.

An object of the present invention is to propose a pile foundation construction method capable of performing construction even in a narrow place and increasing the horizontal passive resistance at a low cost, and a pile foundation constructed by this construction method. .

[0007]

According to the present invention, in a pile foundation method in which a pile is driven into the ground and a footing is constructed on an upper part of the pile, a large rigidity is previously provided around a footing to be constructed. A reinforced concrete sheet pile or a steel sheet pile is buried or cast, and a pile is driven into the space closed by the sheet pile or before the cut-off, and a footing is built on the pile. The present invention proposes a pile foundation method in which a footing is combined with a sheet pile when the footing is constructed, and the sheet pile is left as part of the structure.

Therefore, by employing this pile foundation method, the work space conventionally required becomes unnecessary, and construction can be performed even in a narrow place. In addition, pile foundations constructed by this method leave piles with high rigidity around the footing, so that the horizontal load during an earthquake is mainly received by the piles, so a large resistance to horizontal loads is obtained. Can be. Moreover, since the ground is not softened by pulling out the sheet pile around the footing, there is no possibility that the passive resistance is lowered in the horizontal direction due to the softened surrounding ground. In addition, since the horizontal load is received by the sheet pile, the number of piles can be reduced if the same passive resistance is obtained in the horizontal direction as compared with the conventional pile foundation structure. Also, the diameter of the pile can be reduced. As a result, the advantage that the cost of the pile foundation can be reduced is also obtained.

[0009]

1 and 2 show the structure of a pile foundation constructed by a pile foundation method according to the present invention. FIG.
6 are denoted by the same reference numerals. In the present invention, a sheet pile 50 made of reinforced concrete or steel having high rigidity is buried around a space in which the footing 20 is to be constructed, and the footing construction part is closed. The sheet pile 50 has a dimension D2 in the depth direction that is several times as large as the thickness D1 of the footing 20. Therefore, the ground at the driving portion of the pile 10 is closed by the sheet pile 50 from the surface to the thickness D2.

The pile 1 is placed in the space closed by the sheet pile 50.
A predetermined number of 0s are input. Alternatively, the sheet pile 50 may be buried after the pile 10 is driven in a predetermined number. A footing 20 made of concrete is placed in contact with the head of the driven pile 10. At the time of this driving, the sheet pile 50 acts as a formwork for driving the footing 20 and connects the sheet steel 50 and the reinforcing steel constituting the footing 20, thereby integrating the footing 20 and the sheet pile 50 with concrete.

The sheet pile 50 can be a precast material that has been previously standardized and manufactured at a factory. In addition, an underground continuous wall that continuously casts concrete piles at the site and forms a wall, an underground continuous wall that casts concrete in a wall shape,
Alternatively, it may be constituted by a steel sheet pile or a steel pipe sheet pile having high rigidity. The upper part of the footing 20 shows a case where a desired supported structure, for example, a pier 30 is constructed in the example of FIG.

FIG. 3 shows a modified embodiment of the present invention. In this embodiment, the footing 20 has a large plane area and a large scale. When the footing 20 has a large plane area, the pile 1 is located on the lower side (in the soil) of the footing 20.
In this structure, a partition wall 60 is formed to shield between the soils existing between each other, and the presence of the partition wall 60 enhances the rigidity and the load capacity of the entire foundation.

[0013]

As described above, according to the present invention, the periphery of the footing 20 is closed with the rigid sheet pile 50, and the rigid sheet pile 50 is left in a state of being combined with the footing 20, so that the earthquake is prevented. Sometimes footing 2
Even if a load in the horizontal direction acts on 0, the horizontal load is received by the sheet pile 50, and a large passive resistance can be obtained. Therefore, there is an advantage that the amount of movement of the footing 20 with respect to the horizontal load can be reduced, and the earthquake resistance can be improved.

Further, in the present invention, since the sheet pile 50 is buried in contact with the periphery of the planned construction location of the footing 20, the area required for construction can be reduced. Therefore, there is an advantage that the work can be performed even in a narrow place. Further, since the sheet pile 50 is left, a large passive resistance can be obtained in the horizontal direction. Therefore, even if the number of the piles 10 is smaller than before and the diameter of the pile 10 is smaller, sufficient horizontal resistance can be obtained. Passive resistance can be obtained. Therefore, the number of piles 10 can be reduced, and thin piles can be used, so that an effect that cost reduction can be expected can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA shown in FIG.

FIG. 3 is a sectional view showing a modified embodiment of the present invention.

FIG. 4 is a cross-sectional view for explaining a structure of a pile foundation constructed by a conventional construction method.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a cross-sectional view for explaining a conventional pile foundation method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pile 20 Footing 30 Pier 40 Steel sheet pile 50 Sheet pile 60 Partition wall

Claims (7)

[Claims] 1. A pile foundation construction method in which a plurality of piles are driven into the ground, a footing is constructed on the plurality of piles, and a method of supporting a supported part is provided on the top of the footing. A pile foundation method, wherein the periphery of the pile is closed with a rigid sheet pile and the footing is constructed by combining with the sheet pile. 2. A. A pile foundation including a plurality of piles driven into the ground and a footing constructed on top of the plurality of piles; A pile foundation method, wherein a rigid sheet pile is left in contact with a periphery of the footing. 3. The pile foundation according to claim 2, wherein said sheet pile is made of a reinforced concrete precast material. 4. The pile foundation according to claim 2, wherein said sheet pile is composed of a reinforced concrete column-type continuous underground continuous wall. 5. The pile foundation according to claim 2, wherein said sheet pile is constituted by a reinforced concrete underground continuous wall. 6. The pile foundation according to claim 2, wherein said sheet pile is made of steel sheet pile. 7. The pile foundation according to claim 2, wherein said sheet pile is constituted by a steel pipe sheet pile.