JP2001152446A - Steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel pipe pile, which can be manufactured simply at a low cast and in which deformation is difficult to form in an excavation blade. SOLUTION: Approximately each half of the lower-end cross sections 11a, 11b of a pile body 11 composed of a steel pipe is cut in the severally different inclined directions, and the inclined directions do not cross at right angles in the pile-axial directions respectively, an axial projecting blade 14 is formed by the welding of a plate body, so as to be extended in the same axial direction at approximately the center of the lower-end cross sections of the pile body, each lower-end cross section of approximately halves is welded to each surface of two rectangular plate bodies larger than the lower-end cross sections of approximately halves, and radial projecting blades 12, 13 are formed on both sides holding the axial projecting blade.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe pile driven into the ground by rotation.

[0002]

2. Description of the Related Art A conventional steel pipe pile 50 as shown in FIGS. 5 (a) and 5 (b) has a lower end 51a of a steel pipe pile main body 51 cut in a direction substantially orthogonal to a steel pipe axis.
Are fixed by welding, a drilling blade 54 is projected downward from the bottom plate 52, and a spiral drilling blade 53 is fixed to the outer peripheral surface of the pile main body 51 by welding. In such a steel pipe pile 50, the spiral excavating blade 53 has the purpose of propelling the steel pipe pile 50 in the ground and promoting the transmission of the ground reaction force to the pile main body 51 to bear the load of the building.

[0003]

However, since the spiral excavating blade 53 is formed in a protruding shape fixed at one end, the excavating blade 53 is likely to be deformed when receiving a force from the direction of arrow F when excavating underground. When the excavation blade 53 is deformed, an error also occurs in the excavation direction of the steel pipe pile 50. Therefore, the excavation blade 53 has a circular planar shape, and its outer diameter is limited to about twice the diameter of the steel pipe.

More specifically, the strength of the spiral excavating blade 53 is determined by the following three factors: the thickness of the excavating blade 53, the thickness of the steel pipe of the pile body 51, and the strength of the welded portion 53a. Although it is easy to make a certain excavating blade 53 thick, it is difficult to obtain a certain quality because the strength of the welding portion 53a is highly dependent on the skill of the maker, and in order to increase the strength of the welding portion 53a. However, there is a disadvantage that the steel pipe needs to be thick, and if the above is satisfied, the material cost increases.

Accordingly, an object of the present invention is to provide a steel pipe pile in which the pile itself can be easily manufactured at low cost and the drilling blade hardly deforms.

[0006]

According to the present invention, approximately one half of the lower end cross section of the pile body made of steel pipe has a different inclination angle, and the inclination crosses each other without being orthogonal to the axial direction of the pile body. The plate body is welded so as to extend coaxially at substantially the center of the lower end cross section of the pile body to form an axially projecting blade, and the two piles are larger than the approximately half lower end cross section. The steel pipe pile is provided, wherein the substantially half lower cross-section is welded to each surface of each of the rectangular plates, and radial projecting blades are formed on both sides of the axial projecting blade. Is done.

In the present invention, a steel plate can be used as the plate constituting the radially projecting blade and the axially projecting blade.

[0008]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a side view of a steel pipe pile according to the present invention, FIG. 2 is a side view of the steel pipe pile of FIG. 1 rotated by 90 °, and FIG. 3 is a view of the steel pipe pile of FIG. 1 viewed from below. FIG. 4 is a sectional view taken along line IV-IV in FIG.

1 to 4, a steel pipe pile 10 includes a pile main body 11 made of a steel pipe, an axially projecting blade 14 extending coaxially from the center of the lower end of the pile main body 11, and a pile main body 11.
At the lower end thereof are radially projecting blades 12, 13 welded to both sides of the axially projecting blade 14.

The pile main body 11 has lower end sections 11a, 11a.
b is different from each other by approximately 1/2, and
It is not perpendicular to the axial direction of the pile body, but is formed by cutting at two intersecting inclination angles. That is, the lower end sections 11a and 11b have
When the surfaces of the steel plates constituting the radially projecting blades 12 and 13 are abutted and fixed, these radially projecting blades 12 and 13
The lower end cross sections 11a and 11b are formed so as to have the inclination angles α and β as shown in FIG.

The radially projecting blades 12 and 13 are arranged as shown in FIG.
As shown in FIG. 3, two rectangular steel plates having a long side almost twice as long as the steel pipe diameter D and a short side almost the same length as the steel pipe diameter D are used, and the lower end cross sections 11a and 11b of the pile body 11 are shown in FIG. In the arrangement shown by the dotted line in FIG. 3, each of the steel plates is brought into contact with the surface of the steel plate and fixed by welding 15, and the central portion of the long side of each steel plate is brought into contact with both surfaces of the axially projecting blade 14, respectively. And fixed by welding 16. The axially projecting blade 14 can also be formed of a rectangular steel plate.

Next, the operation of the steel pipe pile 10 will be described.
When the steel pipe pile 10 is excavated in the ground while rotating, as shown by an arrow F in FIG.
Receives the resisting force F from the ground, the lower end sections 11a and 11b of the pile body 11 are fixed on the surfaces of the radially projecting blades 12 and 13, respectively.
The radially protruding blades 12, 1 are formed by the reaction force V from 1a, 11b.
3 is supported, and its deformation is suppressed.

Here, no bending stress acts on the welded portion 15 of the steel pipe pile 10 as compared with the welded portion 53a of the conventional excavating blade 53 shown in FIG.
Irrespective of the strength of the welded portion 15 of the steel pipe, and is obtained by the compressive strength of the pile body 11 in the axial direction of the steel pipe, so that the radially projecting blades 12 and 13 can be sufficiently formed without using a specially large steel pipe. High deformation resistance.

Further, in the steel pipe pile 10 of the present invention, as described above, the radially projecting blades 12, 13 and the axially projecting blade 14 are formed of a flat member such as a steel plate. There is an advantage that the steel pipe pile 10 including the,, and can be easily manufactured. Furthermore, the radially projecting blade 12,
13 and the axially projecting blade 14 are made of a small piece of steel plate as compared with the pile body 11, so that even if a steel plate having a large thickness is used, the material cost does not increase, and therefore, a steel plate having a large thickness is used. Thereby, the strength of the welded portion 16 between the radially projecting blades 12 and 13 and the axially projecting blade 14 can be increased.

[0015]

According to the steel pipe pile of the present invention, almost the entire lower end section of the pile body is welded to the surface of the radially projecting blade except for the portion where the axially projecting blade is attached. Even if a resistance force from the ground acts during the driving of the steel pipe pile, the radially projecting blade is hardly deformed, and the accuracy of the excavation direction of the steel pipe pile can be improved. Further, as described above, since the radially projecting blade is supported by the lower end cross section of the pile main body, it is possible to increase the radially projecting blade, thereby increasing the supporting force of the steel pipe pile after driving. Can be improved.

[Brief description of the drawings]

FIG. 1 is a side view of a steel pipe pile according to the present invention.

FIG. 2 is a side view of the steel pipe pile of FIG.

FIG. 3 is a view of the steel pipe pile of FIG. 1 as viewed from below.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5A is a side view of a conventional steel pipe pile, and FIG.
2 is a longitudinal sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Steel pipe pile 11 Pile main body 11a, 11b Lower end cross section 12, 13 Radially projecting blade 14 Axial projecting blade

Claims (1)

[Claims] 1. A substantially lower section of a lower end section of a pile body made of a steel pipe.
/ 2 each is formed with a different inclination angle, and an inclination angle that does not intersect at right angles with the pile main body axis direction but intersects,
A plate body is welded so as to extend coaxially at substantially the center of the lower end section of the pile body to form an axially projecting blade, and each of the two rectangular plate bodies larger than the substantially half lower end section is formed. A steel pipe pile characterized in that the substantially lower half cross-sections are welded to each other on a surface, and radial projecting blades are formed on both sides of the axial projecting blade.