JP2006193958A - Deformed pile with vane and method making use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pile causing no buckling by improving horizontal ground reaction in the ground and bearing capacity of the front end of the pile without causing torsion in the case of construction. <P>SOLUTION: In the pile used for a pile foundation, a deformed pile with vanes is constituted of four vane bodies respectively extended downward of the axial direction from the upper end of the pile body, it is also constituted of an upper cross-shaped vane 3 placed in a cross-shaped cross section of the four vane bodies and the four vane bodies respectively extended upward of the axial direction from the lower end of the pile body mounted on the outer circumference of the pile body, and a lower cross-shaped vane 4 placed in the cross-shaped cross section of the four vane bodies is also included. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method using a rooted deformed pile and a bladed deformed pile having a novel configuration.

The conventional technology of this type is as follows.
1. Usually, the cross-section of the pile is circular and straight in the length direction.
2. Several types of deformed piles have been proposed, but only an increase in horizontal resistance is considered.

For example, there are things that prevent liquefaction (a phenomenon in which the ground flows during an earthquake and the ground reaction force disappears) by attaching plates or making holes in several places on the outer periphery of the pile. (Patent Document 1)
Alternatively, a cross-shaped jig is attached to the pile head to increase the horizontal resistance of the pile. (Patent Document 2)

Japanese Patent Laid-Open No. 7-127053 JP-A-62-202115

The following problems can be pointed out in the prior art.
1. In a conventional pile having a circular cross section, the joint with the concrete structure is not strong, and there are cases where the horizontal ground reaction force in the ground and the vertical pile tip support force cannot be taken.
2. In a conventional pile having a circular cross section, twisting occurs during construction, and when the pile is constructed by the impact method, the pile head and the pile tip are buckled and there is a concern about pile damage.
The objective of this invention is providing the pile which solved these problems, and its construction method.

In order to solve the above problems, the present invention is as follows.
(1) The profiled pile with a blade according to claim 1 is a pile used for a pile foundation,
An upper cross-shaped shape that is composed of four blade bodies that are mounted on the outer peripheral surface of the pile body and extend downward in the axial direction from the upper end of the pile body, and the cross-sectional shapes of the four blade bodies are arranged in a cross-shape. Feathers,
A lower cross-shaped blade that is mounted on the outer peripheral surface of the pile body and that is composed of four blade bodies extending axially upward from the lower end of the pile body, and in which the cross-sectional shape of the four blade bodies is arranged in a cross shape; It is characterized by having.

(2) According to a second aspect of the present invention, the deformed pile with blades according to the second aspect of the present invention is the blade according to the first aspect, wherein the length in the axial direction is 3 to 4 of the diameter of the pile body. It is characterized by being double.

(3) The deformed pile with blades according to claim 3 is the pile main body according to any one of claims 1 and 2, wherein each of the blade bodies constituting the lower cross-shaped blade has a length in the axial direction. It is characterized by being the same as the diameter.

(4) According to a fourth aspect of the present invention, the deformed pile with blades according to any one of the first to third aspects is perpendicular to the axial direction in each of the blade bodies constituting the upper cross-shaped blade and the lower cross-shaped blade. The width in the proper direction is 1/2 to 1 times the diameter of the pile body.

(5) In the construction method using the bladed deformed pile according to claim 5, the method using the bladed deformed pile according to any one of claims 1 to 4,
Placing the blade-shaped deformed pile so that the lower cross-shaped blade is embedded in the supporting ground;
And fixing the blade-shaped deformed pile so that part of the upper side of the upper cross-shaped blade enters the footing concrete.

  Since the present invention is configured as described above, the following effects can be expected.

1. In the case of the first invention (an irregularly shaped pile with blades according to claims 1 to 4) a) By attaching an upper cross-shaped blade to the upper part of the pile, the pile diameter can be increased in a pseudo manner and the pile head connection can be strengthened. At the same time, it is possible to secure a large horizontal resistance of the pile and increase the ground reaction force at all times during an earthquake. That is, since the pile diameter becomes pseudo large at the upper part of the pile, the horizontal bearing pressure and the punching shear force can be kept small at the joint portion between the footing concrete and the pile. And since a pile diameter can be enlarged freely in the pile upper part of the participation range of a pile horizontal resistance, a horizontal ground reaction force increases.
b) Furthermore, the pile tip supporting force in the vertical direction can be increased by attaching a lower cross-shaped blade to the lower part of the pile. That is, by attaching the lower cross-shaped blade and rooting it into the support ground, the pile tip area and tip closing effect increase, so that a large pile tip support force is secured.
c) Since the pile rigidity is strengthened by attaching the upper cross-shaped blade to the upper part of the pile body and the lower cross-shaped blade to the lower part, torsion during pile construction can be prevented and buckling can be prevented.
d) Compared to producing and constructing large-diameter piles, it is possible to reduce the specifications of the piles of the structure, so that the cost can be greatly reduced.
e) In summary, the bladed deformed pile of the present invention can be used as a foundation pile for structures such as bridges, retaining walls, pipes, and overpasses. It can be expected to increase pile horizontal resistance, secure pile tip support and prevent pile buckling.

2. In the case of the second invention (invention 5) a) By attaching the upper cross-shaped blade and the lower cross-shaped blade to the pile main body, it is possible to prevent damage to the pile due to buckling during pile driving.
b) By attaching the upper cross-shaped blade and the lower cross-shaped blade to the pile body, it is possible to prevent torsion during pile driving and to construct the pile vertically with accurate pile spacing.
c) By using the blade-shaped deformed pile as a group pile, it is possible to obtain a greater support force than when using a normal pile. .

Details of embodiments of the present invention will be described with reference to the drawings.
1st invention is related with the unusually shaped pile with a blade | wing. Drawing 1 is a figure showing the appearance of one example of a deformed pile with a blade. FIG. 2 is a top view of the deformed pile 1 with blades of FIG. 1, and FIG. 3 is a sectional view taken along line XX of FIG.

  As shown in FIG. 1, the deformed pile 1 with a blade includes a pile body 2, an upper cross-shaped blade 3 attached to the upper part of the outer peripheral surface of the pile body 2, and a lower part attached to the lower part of the outer peripheral surface of the pile body 2. It consists of a cross-shaped blade 4. The pile body 2 is a known pre-made pile called a steel pipe pile, for example.

  The upper cross-shaped blade 3 is composed of four blade bodies that extend downward from the upper end of the pile body 2 in the axial direction. Similarly, the lower cross-shaped blade 4 is composed of four blade bodies each extending in the axial direction upward from the lower end of the pile body 2.

  As shown in FIG. 2, the four blade bodies constituting the upper cross-shaped blade 3 are arranged so that the cross-sectional shape in the horizontal direction is a cross shape. That is, in the range 2a from the upper end of the pile main body 2 to a position lowered downward by a predetermined dimension, the front and rear blade bodies 3a, 3a vertically attached around the pile main body 2 in the front-rear direction and the pile main body 2 It is composed of left and right blade bodies 3b and 3b vertically attached with the left and right direction as the center.

  In this case, each of the front and rear blade bodies 3a and 3a and the left and right blade bodies 3b and 3b has a width 3w of about 1/2 to 1 times the diameter D of the pile body 2 and is along the axial direction of the pile body. The length 3h is made of a vertical rectangular iron plate that is about 3 to 4 times the diameter D of the pile body 2, and is attached to the outer peripheral surface of the pile body 2 by welding or the like.

  As shown in FIG. 3, the four blade bodies constituting the lower cross-shaped blade 4 are also arranged so that the horizontal cross-sectional shape is a cross shape. That is, the lower cross-shaped blade 4 has front and rear blade bodies 4a vertically attached with the front and rear directions centered on the pile body 2 in a range 2b from the tip of the pile body 2 to a position raised by a predetermined dimension. 4a and left and right blade bodies 4b and 4b vertically attached with the left and right directions centered on the pile main body.

  In this case, each of the front and rear blade bodies 4a and 4a and the left and right blade bodies 4b and 4b has a width 4w of about 1/2 to 1 times the diameter D of the pile body 2 and is along the axial direction of the pile body. The length 3h is made of a vertical rectangular iron plate that is about 3 to 4 times the diameter D of the pile body 2, and is attached to the outer peripheral surface of the pile body 2 by welding or the like.

  2nd invention is related with the construction method using the unusual pile 1 with a blade | wing of 1st invention. FIG. 4 is a schematic configuration diagram showing a deformed pile 1 with blades in the ground where a single pile is installed by the method of the present invention.

  The target ground on which the bladed deformed pile 1 is constructed is the ground 5, and there is a relatively strong support ground 6 below a predetermined depth of the ground 5. After construction, the tip of the bladed deformed pile 1 is located in a relatively strong support ground 6.

-1st process A single pile is laid in the state in which the tip part of deformed pile 1 with a blade reaches support ground 6. That is, the lower cross-shaped blade 4 is driven so as to be embedded in the support ground 6 (range C).
-2nd process Like the normal joining method, only the length E shorter than the pile diameter D is put into the footing concrete 7, and the upper part of the bladed deformed pile 1 is fixed. That is, it is fixed so that a part of the upper side of the upper cross-shaped blade 3 enters the footing concrete 7 (range A). On the other hand, the lower side of the upper cross-shaped blade 3 is located in the ground 5 (range B).

  As described above, in the constructed deformed pile 1 with blades, it is possible to realize the strengthening of the pile head coupling in the range of A. Further, an increase in horizontal ground force can be realized in the range of B. Furthermore, the tip support force can be secured in the portion in the range of C. As a whole, the effect of strengthening the structure and preventing buckling can be realized.

  FIG. 5 is a schematic configuration diagram showing a plurality of bladed deformed piles 1 in the ground where group piles are installed by the method of the present invention. FIG. 6 is a top view of FIG.

  The target ground on which the plurality of bladed deformed piles 1 are constructed is the ground 5, and there is a relatively strong support ground 6 below a predetermined depth of the ground 5. After the construction, the tip ends of the plurality of bladed deformed piles 1 are located in the relatively strong support ground 6.

-1st process In the state which the front-end | tip part of the deformed pile 1 with a blade | wing reaches the support ground 6, it casts in a group pile shape. In other words, the lower cross-shaped blade 4 is driven so as to be embedded in the support ground 6. In this case, the space | interval F of the adjacent shaped piles 1 with each blade | wing shall be 2.5D or more similarly to a normal pile.

  Moreover, as shown in FIG. 6, it constructs so that the direction of the blade | wing body of adjacent deformed pile 1 with each blade | wing adjacent may become the same on right and left and front and back. This is because in pile design, the axis is perpendicular to the axis against the load.

-2nd process Like the normal coupling | bonding method, only the length shorter than the pile diameter D is put into the upper part of the several shaped blade 1 with a blade | wing with respect to the footing concrete 7, and it fixes. That is, a part of the upper side of the upper cross-shaped blade 3 is fixed so as to enter the footing concrete 7. On the other hand, the lower side of the upper cross-shaped blade 3 is located in the ground 5.

Examples are as follows.
Using the model pile, the effect of the bladed deformed pile 1 of the present invention was tested with a centrifugal force model.
FIG. 7 is an external view showing the shape of the model pile. As for the shape of the model pile, the pile diameter D of the pile body is 10 mm, the length L is 400 mm, the length 3 h of the blade body 3 is 100 mm, and the width 3 w is 5 mm. A weight 17 imitating a footing was attached to the upper end of the pile body 2. The lower end of the pile main body 2 was fixed on the shaking table with soil cement, and the pile main body 2 was placed in the model ground. In addition, a plurality of strain gauges 19 were attached to predetermined positions on the outer peripheral surface of the pile body 2 in order to measure pile stress. The test was a pile horizontal loading test in a 50G field and a vibration test using a sine wave.

  The horizontal loading test and the vibration test were conducted, and it was verified that by attaching the blade 3, the horizontal resistance of the pile increased by about 2 times at all times and by about 3 times at the time of an earthquake than without the blade.

It is a figure which shows the external appearance of one Example of a deformed pile with a blade | wing. It is a top view of the deformed pile 1 with a blade | wing of FIG. It is XX sectional drawing of FIG. It is a typical block diagram which shows the unusual pile 1 with a blade | wing in the ground which installed the single pile by the construction method of this invention. It is a typical block diagram which shows the some shaped pile 1 with a blade | wing in the ground which installed the group pile by the construction method of this invention. FIG. 6 is a top view of FIG. 5. It is an external view which shows the shape of the model pile for a test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaped pile with blade 2 Pile body 3 Upper cross-shaped blade 3a Front and rear blade body 3b Left and right blade body 4 Lower cross-shaped blade 4a Front and rear blade body 4b Left and right blade body 5 Ground 6 Support ground 7 Footing concrete

Claims (5)

In piles used for pile foundations,
An upper cross-shaped shape that is composed of four blade bodies that are mounted on the outer peripheral surface of the pile body and extend downward in the axial direction from the upper end of the pile body, and the cross-sectional shapes of the four blade bodies are arranged in a cross-shape. Feathers,
A lower cross-shaped blade that is mounted on the outer peripheral surface of the pile body and that is composed of four blade bodies extending axially upward from the lower end of the pile body, and in which the cross-sectional shape of the four blade bodies is arranged in a cross shape; An irregularly shaped pile with a blade, characterized by comprising:   2. The deformed pile with blades according to claim 1, wherein in each of the blade bodies constituting the upper cross-shaped blades, the length in the axial direction is 3 to 4 times the diameter of the pile body.   In each of the said blade body which comprises the said lower cross-shaped blade | wing, the length of the said axial direction is the same as the diameter of the said pile main body, The variant with a blade | wing in any one of Claim 1 or 2 characterized by the above-mentioned. Pile.   In each of the blade bodies constituting the upper cross-shaped blade and the lower cross-shaped blade, the width in the direction perpendicular to the axial direction is 1/2 to 1 times the diameter of the pile body. The bladed deformed pile according to any one of claims 1 to 3. In the construction method using the deformed pile with a blade according to any one of claims 1 to 4,
Placing the blade-shaped deformed pile so that the lower cross-shaped blade is embedded in the supporting ground;
And a step of fixing the bladed deformed pile so that a part of the upper cross of the upper cross-shaped blade enters the footing concrete. A method using the bladed deformed pile.

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