JP2003213675A

JP2003213675A - Wall pile

Info

Publication number: JP2003213675A
Application number: JP2002017076A
Authority: JP
Inventors: Akihiro Takeuchi; Yoshio Takeuchi; 義夫武内; 章博竹内
Original assignee: Nishimatsu Constr Co Ltd; 西松建設株式会社
Priority date: 2002-01-25
Filing date: 2002-01-25
Publication date: 2003-07-30

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wall pile capable of improving earthquake resistance more than a conventional wall pile by uniforming the directional property of horizontal support force and reducing the drilling earth quantity of a surface layer ground or the use quantity of a material for forming the wall pile in the construction of the wall pile. <P>SOLUTION: This wall pile 10 comprises a pile head part 1 having a cross sectional shape such that the cross sections before and after rotation are matched when rotated 90° around the center of the cross section, and buried in the vicinity of the ground surface; a pile shaft part 2 smaller in width than the pile head part 1, integrally formed on the lower end of the pile head part 1, and buried in the surface layer ground 5 under the vicinity of the ground surface; and a pile bottom part 3 larger in width than the pile shaft part 2, integrally formed on the lower end of the pile shaft part 2, stronger than the surface layer ground 5, and buried in a support layer 6 located under the surface layer ground 5. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a wall pile.

[0002]

2. Description of the Related Art As shown in FIG.
It is a wall-shaped pile constructed by the underground continuous wall method and is used at many construction sites. In addition, for example, Japanese Patent Laid-Open No.
Japanese Patent Publication No. 001-226987 discloses an underground continuous wall having a structure similar to that of the wall pile of FIG. Wall stake 20
Has a rectangular cross section, and the upper end of the wall pile 20 is joined to a foundation 4 such as a footing, an underground beam, and a pressure plate constructed on the ground, and from the upper end to a vertically downward direction through the surface ground 5. And the lower end is rooted in the support layer 6 under the surface ground 5, and supports the foundation 4 and the building constructed on the foundation 4. The support layer 6 is a firmer ground than the surface ground 5.

[0003]

By the way, the wall pile plays a role of supporting the foundation and the building on the foundation as described above. However, since the cross section of the wall pile is rectangular, the horizontal bearing capacity is increased. The directionality of the foundation is not uniform, and when a large earthquake occurs, the foundation is eccentric and the inclination of the foundation or the structure on the foundation
May cause collapse. In addition, since bending stress and shearing stress generated in the wall pile differ depending on the depth position from the ground surface, if the width from the upper end to the lower end of the wall pile is made the same as in the conventional case, the surface ground when constructing the wall pile will be There was a problem that the amount of excavated soil and the amount of materials such as concrete used to form wall piles were increased more than necessary.

Therefore, an object of the present invention is to improve the seismic resistance as compared with the conventional wall pile by making the direction of the horizontal bearing force uniform, and to excavate the amount of soil excavated in the surface ground when constructing the wall pile. An object of the present invention is to provide a wall pile that can reduce the amount of material used to form the wall pile.

[0005]

In order to solve the above problems, the invention according to claim 1 is, for example, as shown in FIGS. 1 and 2, a foundation 4 and a building on the foundation which are buried in the ground. It is a wall pile 10 that supports, with the center of the cross section as the axis.
It has a cross-sectional shape that the cross-sections match before and after the rotation when it is rotated by 0 degree, and the pile head 1 buried near the ground surface of the ground and the width narrower than the width of this pile head are used. And a pile shaft portion 2 integrally formed at the lower end of the pile head and embedded in the surface ground 5 below the surface of the earth, and a width wider than the width of the pile shaft portion. It is characterized in that it is integrally formed at the lower end of the shaft portion, and is provided with a pile bottom portion 3 which is stronger than the surface ground and is embedded in the support layer 6 below the surface ground.

According to the invention described in claim 1, when a large earthquake occurs, the largest bending stress and shear stress are generated in the pile head formed near the ground surface of the ground. When rotated 90 degrees around the center of the cross section,
Since it has a cross-sectional shape in which the cross-sections are the same before and after rotation, the directionality of the horizontal bearing force can be made uniform, and it has seismic resistance against seismic waves from multiple directions. Also, since the bending stress and shearing stress of the pile head are not generated in the pile shaft,
Even if the width is narrower than the width of the pile head, the horizontal force can be sufficiently supported. Also, the pile bottom has a width wider than the width of the pile shaft, is stronger than the surface ground, and is embedded in the supporting layer below the surface ground, so the width of the pile shaft is narrow. This prevents the vertical support force from decreasing. in this way,
In the wall pile of the present invention, the directionality of the horizontal supporting force can be made uniform and the vertical supporting force can be prevented from lowering, so that the earthquake resistance can be improved as compared with the conventional wall pile. In addition, since the width of the pile shaft portion is narrowed, it is possible to reduce the amount of excavated soil in the surface ground and the amount of material used to form the wall pile when constructing the wall pile.

According to a second aspect of the present invention, for example, as shown in FIGS. 1 and 2, in the wall pile according to the first aspect, the pile head has a plurality of wall bodies that divide the width of the wall body into two halves. It is characterized in that it is integrally formed so as to intersect at a position.

According to the invention of claim 2, the pile head is
Since the plurality of wall bodies are integrally formed so as to intersect each other at a position that divides the width of the wall body into two, the structure is simple,
Design and construction become easy, and construction cost can be reduced.

The invention according to claim 3 is, for example, as shown in FIGS. 1 and 2, in the wall pile according to claim 2, the number of the wall bodies is two, and these wall bodies are mutually wall bodies. Is formed integrally so as to be orthogonal to each other at a position that divides the width of the.

According to the invention described in claim 3, the pile head is
Since the two wall bodies are integrally formed so as to be orthogonal to each other at a position that bisects the width of the wall body, it is possible to minimize the components required to make the directionality of the horizontal supporting force uniform. Further, the structure is simple, the design and construction are easy, and the construction cost can be reduced.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A wall pile according to an embodiment of the present invention will be described in detail below with reference to the drawings. At first,
The structure of the wall pile will be described. The same components as those of the wall pile 20 described in the related art will be described with the same symbols. As shown in FIGS. 1 and 2, the wall pile 10 is embedded in the ground to support the foundation 4 and a building on the foundation 4, and the pile head 1, the pile shaft portion 2, and the pile bottom portion 3 are provided. Are integrally formed.

When the pile head 1 is rotated 90 degrees about the center of the horizontal cross section so that the horizontal bearing force with respect to seismic waves from multiple directions becomes uniform, the cross sections of the pile head 1 match before and after the rotation. It has a cross-sectional shape such as that which prevents tilting or collapse of the foundation 4 and the building on the foundation 4 when a large earthquake occurs. It is formed from a wall body having a shape (see FIG. 2A). Further, the pile head 1 is buried in a portion where the largest bending stress or shear stress is generated when a large earthquake occurs, that is, near the ground surface in the surface ground 5, and as shown in FIG. It is arranged so that the upper end is almost flush with the ground surface. In addition, the pile head 1 is not limited to the cross-section substantially cross shape, but may be the cross-section substantially US shape, the cross-section circular shape, the cross-section substantially square shape, or the like. Further, the material forming the pile head 1 is not limited to concrete, and soil cement may be used.

The pile shaft portion 2 supports the pile head portion 1 in the surface layer ground 5, and is formed of, for example, a wall body made of concrete and having a rectangular cross section (see FIG. 2 (b)). There is. In addition, the pile shaft portion 2 has an upper end integrally formed with the lower end of the pile head 1, extends vertically downward from the upper end, and has a lower end that is stronger than the surface soil 5 and is also the surface soil. It is arranged so as to be located at the boundary between the support layer 6 and the surface layer ground 5 below 5. Further, since the pile shaft portion 2 is separated from the ground surface, when a large earthquake occurs, the bending stress and the shear stress as large as those of the pile head portion 1 do not occur, and the width of the pile head portion 1 is smaller than that of the pile head portion 1. Has a narrow width. The support layer 6 is preferably a naturally existing strong rock layer or the like, or a treated soil layer that has been subjected to ground improvement in advance if the surface layer 5 is soft.

The pile bottom portion 3 is a pile shaft portion 2 for supporting the pile head portion 1.
Is supported in the support layer 6, and is formed of, for example, a wall body made of concrete and having a rectangular shape in cross section (see FIG. 2C). Further, as shown in FIG. 1, the pile bottom portion 3 is embedded in the support layer 6 such that the upper end thereof is substantially flush with the boundary between the surface ground 5 and the support layer 6, and further, the pile shaft 3 It is formed integrally with the lower end of the portion 2. Further, the pile bottom portion 3 has a width wider than the width of the pile shaft portion 2, and prevents the vertical support force from being reduced due to the narrow width of the pile shaft portion 2.

Next, a method of constructing the wall pile 10 will be described with reference to FIGS. 3 and 4. To build the wall stake 10, first use a general-purpose excavator, as shown in FIG.
Excavate two first excavation parts 71. At that time, an interval slightly shorter than the length of the first excavation part 71 is provided between the first excavation parts 71.

Next, one second excavation part 72 is excavated so as to connect the two first excavation parts 71. At this time, the second excavation part 72 is excavated so as to overlap a part of the first excavation part 71, whereby a substantially oval hole is formed. Also,
The length L of the formed hole is slightly longer than the width of the pile head 1. Hereinafter, the first excavation part 71 and the second excavation part 72 are alternately excavated up to a depth of the pile head 1, for example, about 5 m from the ground surface.

When the excavation of the first excavation part 71 and the second excavation part 72 is completed, as shown in FIG. 4, the same procedure is performed in the direction orthogonal to the longitudinal direction of the first excavation part 71 and the second excavation part 72. The two third drilling parts 73 and one fourth drilling part 74 are drilled. The third excavation unit 73 and the fourth excavation unit 74
Is formed so that the fourth excavation portion 74 is aligned with the position orthogonal to the second excavation portion 72. As a result, the surface ground 5 is excavated in a substantially cross shape slightly larger than the cross section of the pile head 1.

Next, the excavated second excavated portion 72 is further excavated to the boundary between the surface layer ground 5 and the support layer 6. Then
By using an excavator equipped with a widening bucket, the support layer 6 is excavated to a predetermined depth while widening the width of the second excavation portion 72 to form the excavation hole 7. Finally, a reinforcing steel cage (not shown) is inserted into the excavation hole 7, concrete is placed, and the wall pile 10
To build.

Next, the operation of the wall pile 10 when a large earthquake occurs will be described. If a large earthquake occurs and in the conventional case, the wall pile 10 has a poor horizontal bearing capacity, that is, if the seismic wave propagates from the front (back) side to the back (front) side with respect to the paper surface of FIG. 1, the surface ground 5 Since the vicinity of the pile head 1 shakes most inside, the largest bending stress and shear stress are generated in the pile head 1. Here, since the cross section of the pile head 1 is substantially cross-shaped, the pile head 1 is left (right) with respect to the plane of FIG.
It exerts the same horizontal bearing capacity as when a seismic wave propagates from one side to the right (left) side. Further, since bending stress and shearing stress generated in the pile shaft portion 2 integrally formed at the lower end of the pile head portion 1 are much smaller than those in the pile head portion 1, the pile shaft portion 2 is Even if the width is narrower than the above, the influence of these stresses is small and the pile head 1 can be sufficiently supported. Further, the pile bottom portion 3 formed integrally with the lower end of the pile shaft portion 2 has a width wider than that of the pile shaft portion 2 and prevents the vertical supporting force from decreasing.

According to the wall pile 10 of the present embodiment, since the cross section of the pile head 1 is substantially cross-shaped, the directionality of the horizontal supporting force is substantially uniform. Therefore, when a large earthquake occurs,
The eccentricity of the foundation 4 on the wall pile 10 can be eliminated, and the foundation 4 and the foundation 4
It is possible to prevent the upper building from tilting or collapsing. Further, since the maximum values of bending stress and shear stress occur near the ground surface in the surface ground 5, the width of the pile shaft portion 2 can be made narrower than the width of the pile head 1, and the amount of excavated soil in the surface soil 5 can be reduced. The amount of material used for the wall pile 10 can be reduced. Further, since the pile bottom portion 3 is wider than the pile shaft portion 2, even if the width of the pile shaft portion 2 is narrowed, the vertical support force is not reduced.

The present invention is not limited to the above embodiment. For example, the shape, material, size, etc. of the pile head portion, the pile shaft portion, and the pile bottom portion can be modified within the scope of the invention.

[0022]

According to the invention of claim 1, the wall pile is
Since the direction of the horizontal bearing capacity can be made uniform and the vertical bearing capacity can be prevented from decreasing, seismic resistance can be improved compared to conventional wall piles. In addition, since the width of the pile shaft portion is narrowed, it is possible to reduce the amount of excavated soil in the surface ground and the amount of material used to form the wall pile when constructing the wall pile.

According to the invention of claim 3, the pile head is
Since the two wall bodies are integrally formed so as to be orthogonal to each other at a position that bisects the width of the wall body, it is possible to minimize the components required to make the directionality of the horizontal supporting force uniform. Further, the structure is simple, the design and construction are easy, and the construction cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view for explaining a wall pile according to an embodiment of the present invention.

FIG. 2 is a transverse cross-sectional view for explaining the wall pile in the above embodiment.

FIG. 3 is a schematic diagram for explaining a method of excavating the surface layer ground when constructing the wall pile in the above embodiment.

FIG. 4 is a schematic diagram for explaining a method for excavating the surface ground when constructing the wall pile in the above-described embodiment.

FIG. 5 is a vertical cross-sectional view for explaining a wall pile in the related art.

[Explanation of symbols]

1 pile head 2 pile shaft 3 pile bottom 4 basics 5 surface ground 6 Support layer 10 wall stakes

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Claims

[Claims]

1. A wall pile that is buried in the ground and supports a foundation or a structure on a foundation, and when the cross section is rotated 90 degrees about the center of the cross section, the cross sections before and after the rotation match. A pile head that has a unique cross-sectional shape and is buried near the surface of the ground, and a width that is narrower than the width of this pile head, and is integrally formed at the lower end of the pile head, A pile shaft portion that is embedded in the lower surface layer ground, and a width that is wider than the width of this pile shaft portion, is integrally formed at the lower end of the pile shaft portion, is stronger than the surface layer ground, and is also the surface layer ground. A wall pile, comprising: a pile bottom portion embedded in a lower support layer.

2. The wall pile according to claim 1, wherein the pile head is integrally formed so that a plurality of wall bodies intersect each other at a position that bisects the width of the wall body. Wall stake.

3. The wall pile according to claim 2, wherein the number of the wall bodies is two, and these wall bodies are integrally formed so as to be orthogonal to each other at a position that bisects the width of the wall body. A wall pile characterized by.