JPS6225816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a concrete helical pile used for the foundation of a relatively small-scale building, such as a house.

[Problem to be solved by the invention]

Various spiral piles have been proposed and known for a long time, in which spiral wing pieces are continuously or intermittently protruded from the outer periphery of the pile and are inserted into the ground by screwing. However, there are almost no examples of practical use in Japan.

By the way, in small buildings such as houses, 1 to 3
It has been implemented to convert small-diameter piles of about 100 m in diameter into helical piles. If this small-diameter hole is used as a foundation pile, it can be rotated and inserted into the ground with a simple tool, so it is considered to be easy to construct and have a large bearing capacity. However, experimental results show that, depending on the geology, there are many cases in which a large amount of earth and sand is discharged, or in which it is difficult to screw in.

This invention was developed to improve these problems.

[Structure and embodiments of the invention]

The drawings show an embodiment of the present invention, and this spiral pile consists of a main body 1 with a circular cross section and spiral wing pieces 2 protruding from the outer periphery of the main body 1. Moreover, concave portions 3 which are planar and curved are formed at required intervals in the blade 2, and the outer periphery of the blade 2 is bent in a wavy manner intermittently. They are arranged in a straight line in the horizontal direction. In this concave portion 3, a portion corresponding to the wing piece 2 is assumed to protrude slightly. The wing piece 2 has a shape that protrudes in three directions when viewed from above. Furthermore, the side edges of the concave portion 3 are more gently sloped on the cutting edge side 4 than on the other side. In other words, as shown in the figure, the pile rotates in the direction of the arrow, and the cutting edge side 4 bites into the ground, but as an example, the angle of the cutting edge side 4 is 60 degrees in the radial direction, while the angle of the other side is 30 degrees.゜.

The pile may have the same diameter over its entire length, or may have a diameter that gradually decreases toward the tip. In addition, the tip is made of concrete or metal 5
shall be established as appropriate. Further, screwing can be facilitated by gradually decreasing the protruding length of the wing piece 2 toward the tip.

Further, a joint fitting 6 is provided protruding from the top of the pile to be connected to a pile screwing tool or to be used as a joint pile. Further, a groove 7 into which a joint fitting 6 is inserted is formed at the lower end of the upper pile.

Further, the upper end of the reinforcing reinforcing bar 8 is welded and attached to the side wall surface of the part of the joint fitting 6 that is buried in the concrete. Furthermore, after the piles are buried underground, anchor reinforcing bars buried in concrete such as a cloth foundation or footing are appropriately inserted into the joint fittings 6 and attached.

〔Effect of the invention〕

In the spiral pile of this invention, the wing pieces of the spiral pile are wave-like and intermittent, and concave portions are formed at required intervals, and the cutting edge side is gently sloped, so that it is difficult to excavate the ground when screwing into the ground. However, since many cutting edges are formed to cut the earth and sand,
Screwing resistance is low and screwing is easier than in the case of connected helical blades. In addition, connected spiral blades lift soil to the ground surface, but since the blades of this invention have an intermittent wave shape, they lift less earth and sand and press the earth and sand into the ground. This will also help strengthen the ground. Furthermore, there is no risk of damage to the wing pieces.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are a plan view and a side view of the main parts of the pile according to the present invention, Figure 4 is a longitudinal sectional view, and Figure 5 is a longitudinal sectional view.
The figure is a side view of reinforcing bars and joint fittings. 1... Main body, 2... Wing piece, 3... Concave portion, 4...
...Cutting blade side, 5...Shoe, 6...Joint fitting, 7...Concave groove, 8...Reinforcing bar, 9...Anchor bar.

Claims (1)

[Claims] 1 Spiral wing pieces are protruded from the outer periphery of the main body with a circular cross section, and the wing pieces are formed with flat curved concave portions at required intervals, and the outer periphery of the wing pieces is bent in a wavy manner. What is claimed is: 1. A helical pile characterized in that the cutting edge side of the concave portion is intermittent and that the cutting edge side of the concave portion is sloped more gently than the other side, and the concave portion is arranged in a linear position in the length direction of the main body.