JPH08291518A - Steel pipe pile with spiral blade - Google Patents

Abstract

PURPOSE: To bury a steel pipe pile correctly and stably without the movement of the steel pipe pile during work in a position preset as a burying place for the steel pipe pile so that a burying work progresses smoothly by eliminating the unbalanced force generated by the rotation of the steel pipe pile to the utmost. CONSTITUTION: In a steel pipe pile 1 having a spiral blade 3 fixed to the outer peripheral end part of a steel pipe 2, the spiral blade 3 comprises several spiral blades, and the vicinity of the lower end of the outer periphery of the steel pipe 2 is taken as the start end 4 of each spiral blade 3. Several spiral blades 3 are positioned at equal intervals round the outer periphery of the steel pipe, and the length of each spiral blade 3 is substantially set to a length of (one divided by a number of blades) turn. At the start end 4 of the spiral blade 3, the height of the spiral blade is gradually decreased to add an incomplete blade part 5 extended to the lower end of the outer periphery of the steel pipe 2.

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 with spiral blades. At the position where the steel pipe pile should be buried,
It can be applied to a construction method for burying accurately and stably.

[0002]

2. Description of the Related Art A steel pipe pile having spiral blades at the lower end of the steel pipe pile is disclosed in Japanese Examined Patent Publication No. 2-62648 (JP-A-59-85).
No. 028) is known. Tokkyo 2-6
As shown in FIG. 4, the steel pipe pile 8 of No. 2648 has a bottom plate 9 fixed to the lower end of the pile main body, an excavating blade 10 provided on the bottom plate 9, and a spiral for screwing the pile into the lower end of the pile main body. Wings (spiral blades)
11, the steel pipe pile 8 is rotated and pressed into the ground, the earth and sand at the tip of the pile body is weakened by the excavating blade 10 at the tip, and the spiral blade 11 is inserted into the unexcavated earth and sand on the side surface thereof. It is something that is screwed in like a cut.

[0003]

As described above, the steel pipe pile of Japanese Patent Publication No. 2-62648 is provided with the spiral blades 11 for cutting the earth and sand, but the spiral blades 11 continuously have a single blade. Since the structure has one winding, when a steel pipe is buried by applying a rotating force at the place where the steel pipe pile is buried, an unbalanced force is generated with respect to the center of rotation of the steel pipe pile, and the axial center of the steel pipe pile is generated. It occurs that the slab moves from the position where it is positioned to be buried. Further, the movement of the steel pipe pile during the burying work not only impairs the smooth progress of the burying work, but also reduces the construction accuracy.

In view of the above-mentioned problems of the prior art, the object of the present invention is to eliminate the unbalanced force generated during the burying work due to the rotation of the steel pipe pile as much as possible, and work at the position set as the burying place of the steel pipe pile. It is an object of the present invention to provide a steel pipe pile with spiral blades, which enables accurate and stable burying of the steel pipe pile without moving the steel pipe pile therein and which enables the burying work to proceed smoothly.

[0005]

In the steel pipe pile with spiral blades and the steel pipe pile in which spiral blades are fixed at the outer peripheral end of the steel pipe according to the present invention, the spiral blades are several spiral blades. The lower end of the outer circumference of the steel pipe serves as the starting end of the spiral blade, and the above-mentioned several spiral blades are arranged at equal intervals around the outer circumference of the steel pipe. Here, in the present invention, the spiral blade fixedly provided on the outer peripheral end of the steel pipe is a spiral blade of several threads, but preferably has two threads or three threads. This is because if the number of threads is increased too much, the structure will become complicated as a steel pipe pile, and the relaxation of the unbalanced force will not increase so much. Several spiral blades are placed at equal intervals around the outer circumference of the steel pipe. Therefore, in a plan view of several spiral blades, the spiral blades are arranged at an equal pitch around the outer circumference of the steel pipe. In this way, the reaction force generated by each spiral blade when a torque is applied to the steel pipe pile maintains the equilibrium as much as possible. The winding length of each spiral blade is preferably approximately (1 / (number of threads)). The total winding length of each spiral blade is approximately one. This level is enough to cause the spiral blade to be caught in the formation by the rotating force and to propel the steel pipe pile vertically in the formation. If the winding length is too long, the resistance of the sand and sand increases with each spiral blade. Because it will be.

Further, the steel pipe pile with spiral blades of the present invention is a steel pipe pile in which spiral blades are fixed at the outer peripheral end of the steel pipe, wherein the spiral blades are several spiral blades. The vicinity of the lower end of the outer circumference is taken as the start end of the spiral blade, the above-mentioned several spiral blades are positioned at equal intervals around the outer circumference of the steel pipe, and the height of the spiral blade is gradually reduced at the start end of the steel pipe. It is configured by additionally providing an incomplete blade portion reaching the lower end of the outer periphery of the. In the present invention, the shape of the spiral blade may be, for example, a surface formed by a perpendicular line of the same length provided from a point that draws a spiral trajectory on the outer peripheral surface of the steel pipe of the steel pipe pile. In the present invention, it is preferable that such a spiral blade is provided with an incomplete blade portion that gradually decreases the height of the spiral blade at the start end of the spiral blade and reaches the lower end of the outer circumference of the steel pipe. The presence of such incomplete blade portions can suppress the reaction force of the ground at the start of penetration of the steel pipe pile to be small. This contributes to preventing an unexpected movement of the steel pipe pile from the set position to be buried at the start of burying the steel pipe pile. When the incomplete blade portion is provided, the position where the spiral blade, which is the complete blade portion, is provided shifts from the lower end to the upper portion. The outer diameter D of the spiral blade is preferably (1.5 to 2.0) times the outer diameter d of the steel pipe.

[0007]

According to the present invention, in the steel pipe pile in which the spiral blades are fixed at the outer peripheral end of the steel pipe, the spiral blades are several spiral blades, and the lower end of the outer periphery of the steel pipe is the starting end of the spiral blade. By arranging the above-mentioned several spiral blades at equal intervals around the outer circumference of the steel pipe, the reaction force received by the steel pipe pile from the ground when penetrating by applying a rotational force is balanced.
Further, by making the length of each spiral blade approximately (1 / (number of threads)) winding length, the steel pipe pile is propelled vertically into the formation without increasing the resistance of the sand and sand by each spiral blade. Further, the height of the spiral blade is gradually reduced at the start end of the spiral blade, and an incomplete blade portion reaching the lower end of the outer circumference of the steel pipe is added to provide a reaction force at the start of penetration of the steel pipe pile. It can be kept small.

[0008]

An embodiment of the present invention will be described with reference to the drawings.
1 and 2, there is shown a steel pipe pile 1 in which a spiral blade 3 is fixed at an outer peripheral end of a steel pipe 2. In this example,
The spiral blade 3 is a two-row spiral blade, and each of the steel pipes 2
The vicinity of the lower end of the outer circumference of the spiral blade 3 is defined as the starting end 4 of the spiral blade 3, and the two spiral blades 3 are positioned at equal intervals around the outer circumference of the steel pipe 2, and the length of each spiral blade 3 is (1 / (2 rows)) = The length should be 1/2 roll. In this way, the generation of the unbalanced force when the spiral blade is provided is eliminated as much as possible. Further, in this example, at the starting end 4 of the spiral blade 3, the height of the spiral blade 3 is gradually reduced, and an incomplete blade portion 5 reaching the lower end of the outer circumference of the steel pipe 2 is additionally provided. This is for alleviating the impact due to the reaction force at the start of penetration of the steel pipe pile 1. In FIG. 1, the length of 1 is a half pitch of the spiral blade 3.

FIG. 3 is a perspective view of the lower end of the steel pipe pile 1 of the present invention seen from below. A bottom plate 6 for closing the opening at the lower end of the steel pipe pile 1 is provided, and two cutting blades 7 are attached to the bottom plate 6. ing.
In this example, the outer diameter D of the spiral blade is twice the outer diameter d of the steel pipe.

[0010]

The present invention has the following effects. (1) The present invention alleviates unbalance of reaction force from the ground when a steel pipe pile is subjected to a rotational force to penetrate the steel pipe pile, and prevents the steel pipe pile from moving from a setting position to be buried, Accurate construction can be performed smoothly. (2) By adding an incomplete blade part to the spiral blade, the reaction force from the ground when the steel pipe pile penetrates is mitigated, unexpected movement of the steel pipe pile is prevented, and more accurate construction can be performed. it can.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a perspective view of the lower end of the steel pipe pile of the present invention seen from below.

FIG. 4 is a diagram showing a conventional technique.

[Explanation of symbols]

 1 Steel Pipe Pile 2 Steel Pipe 3 Spiral Blade 4 Starting Point 5 Incomplete Blade 6 Bottom Plate 7 Excavation Blade 8 Steel Pipe Pile 9 Bottom Plate 10 Cutting Blade 11 Spiral Blade

Claims (5)

[Claims] 1. A steel pipe pile in which spiral blades are fixed at the outer peripheral end of a steel pipe, wherein the spiral blades are several spiral blades, and the lower end of the outer periphery of the steel pipe is the starting end of the spiral blades. A steel pipe pile with spiral blades, characterized in that the above-mentioned several spiral blades are arranged at equal intervals around the outer circumference of the steel pipe. 2. In a steel pipe pile in which spiral blades are fixed at the outer peripheral end of the steel pipe, the spiral blades are several spiral blades, and the lower end of the outer periphery of the steel pipe is the starting end of the spiral blades. Steel pipe pile with spiral blades, characterized in that the above-mentioned several spiral blades are arranged at equal intervals around the outer circumference of the steel pipe, and the length of each spiral blade is approximately (1 / (number of threads)) winding length. . 3. A steel pipe pile having spiral blades fixed to the outer peripheral end of a steel pipe, wherein the spiral blades are several spiral blades, and the vicinity of the lower end of the outer periphery of the steel pipe is the starting end of the spiral blade. , The above-mentioned several spiral blades are arranged at equal intervals around the outer circumference of the steel pipe, and the height of the spiral blade is gradually reduced at the starting end of the spiral blade, and the incomplete blade portion reaching the lower end of the outer circumference of the steel pipe is Steel pipe pile with spiral blades, which is characterized by being additionally provided. 4. A steel pipe pile in which spiral blades are fixed at the outer peripheral end of the steel pipe, wherein the spiral blades are several spiral blades, and the vicinity of the lower end of the outer periphery of the steel pipe is the starting end of the spiral blade. , The above-mentioned several spiral blades are arranged at equal intervals around the outer circumference of the steel pipe, and the length of each spiral blade is approximately (1 /
(Number of threads)) The winding length is set, and the height of the spiral blade is gradually reduced at the start end of the spiral blade, and an incomplete blade portion reaching the lower end of the outer circumference of the steel pipe is added. Steel pipe pile with spiral blades. 5. The steel pipe pile with spiral blades according to claim 1, 2, 3, or 4, wherein the number of spiral blades is two or three.