JPS6160926B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pile fixing method used in construction and civil engineering.

(Prior Art and Problems) Types of piles used in construction and civil engineering include support piles and friction piles. The method of fixing friction piles has conventionally been carried out as shown in FIGS. 1A to 1C. 1 is the concrete pile body, and 2 is the ground. The pile body 1 is formed with knot-shaped protrusions 3. In order to fix a friction hole formed with a knot-shaped protrusion into the soil to a predetermined depth, pour sand 4 into the recess each time a knot is driven, and remove the gap between the ground and the pile body. It was necessary to blend it in with the ground. Furthermore, the larger the cross-sectional area of the knot-like protrusions 3, the greater the force required for pouring, necessitating the use of a large-sized pouring machine. If a buried construction method is adopted instead of a method of pouring, a large diameter vertical hole into which the protrusion 3 is inserted is required, and a machine must be used to excavate this hole. In any case, the conventional method of fixing friction piles has the drawback of requiring large machinery, resulting in high construction costs. In addition, it took time and effort to fill the recesses with sand. Furthermore, because the gap between the pile and the ground was eliminated through the sand, it was difficult to obtain sufficient friction with the ground. Furthermore, since the tip of the pile was sharp to make it easier to drive, it was not stable as a support pile.

(Means for Solving the Problems) The pile fixing method of the present invention consists of a hollow pile body formed by forming a plurality of slits at several points around the tip and the middle, and an opening at the tip of the hollow pile body. After closing the opening at the end of the pile body with the pile tip metal fitting, the pile body is driven into the soil from the pile tip metal fitting to the desired depth, and then, An expansion agent is put into the pile body, and as time passes, the slit portions formed at the pile tip and in the middle of the pile body are expanded at multiple locations.

(Example) Reference numeral 5 denotes a hollow pile body made of metal or synthetic resin material, and the tip 5a and the middle 5b of this pile body 5.
A plurality of slits 6a, 6b, and 6c are formed around the periphery. These slits are preferably formed along the axial direction or at an angle with respect to the axial direction, but the middle slits 6b, 6c, etc. may be formed approximately at right angles to the axial direction. .

The slits 6a, 6b, and 6c are respectively attached to the pile body 5.
It is desirable to form two or more of them around the circumference.
The length and number of slits are determined depending on the expansion performance of the expansion agent, which will be described later. Reference numeral 7 denotes a pile tip metal fitting, which is fitted into the tip opening of the pile body 5 to close it. It is desirable that the pile tip metal fitting 7 is a bullet-shaped metal fitting with a pointed tip.
Why, when driving the pile body 5 into the soil,
This is because it is important that soil does not enter the pile body and that it is easy to drive.

A small shaft body 7b that fits into the opening at the tip of the pile body 5 projects from the rear surface 7a of the pile tip metal fitting 7. Therefore, in order to attach the pile tip fitting 7 to the tip of the pile body 5, it is sufficient to fit the small shaft body 7b into the tip opening of the pile body 5. With this configuration, the tip of the pile main body 5 is received by the rear surface 7a of the pile tip fitting 7. In addition, the outer diameters of the pile tip fitting 7 and the pile body 5 are formed to be the same.

In this way, the pile body 5 and the pile tip fitting 7 are formed,
After fitting the pile tip fitting 7 into the tip opening of the pile body 5,
This pile body 5 is driven into the soil.

After the pile body 5 is placed in the soil at a desired depth, an expansion agent 8 is injected into the inside of the pile. Expanding agent 8 is an agent that, when mixed with water and filled into a target hole or cylinder, hardens and expands to cause planned cracking and expansion in the target object.For example, a product manufactured by Onoda Cement Co., Ltd. The name is Bleister etc.

After injecting the swelling agent 8 into the inside of the pile in this way, approximately
After 15 to 24 hours have elapsed, as shown in FIG. 6, the slit portions provided at the tip and middle of the pile body 5 are enlarged by the hardening and expansion of the expanding agent.
The expansion agent 8 expands 2 to 3 times within the pile. Since the tip and middle part of the pile expands and expands in a knot-like manner at multiple locations, the pull-out resistance becomes large and the supporting force at the tip also increases.
In order to expand the pile, the parts other than those forming the slits 6a may be filled with concrete or the like instead of the expanding agent. In other words, since the expansion agent is expensive, it is preferable to fill the area other than the area to be expanded with inexpensive concrete or the like. It is also conceivable to mix the expanding agent and concrete and inject it into the pile.

The expansion agent solidifies to some extent and expands inside the pile body over time. Therefore, the amount of the expanding agent flowing out from each slit is small, and the expanding agent forms a lump and expands the diameter of the pile body at each slit.

(Effects of the Invention) The construction method of the present invention as described above has the following effects.

(1) Conventional friction piles lacked stability as support piles because their tips were sharpened for ease of driving, but the piles produced using the method of the present invention The stability of the support pile is extremely high due to its expansion. In addition, the pile also has characteristics as a friction pile.

(2) Conventional friction piles have knots in several places in the middle of the pile body, so driving requires a huge force and a powerful driving machine, but with the method of the present invention, it is possible to drive straight pipes. Because of this, driving is smooth and the work can be done quickly with little force.

(3) Since a pointed bullet-shaped pile tip fitting is fitted into the opening at the end of the hollow pile body, it is possible to quickly drive the pile body into the soil, and the pile body Easy to manufacture. In addition, the small shaft protruding from the rear of the pile tip fitting is inserted into the pile body, and the rear face receives the tip of the pile body, so even when driving into the soil, the pile body does not touch the soil. It cannot be destroyed by resistance.

(4) After the pile body is driven into the soil to the desired depth, the specified position is expanded using an expanding agent, which allows the pile body to fit closely with the soil, providing reliable support and friction. can get.

(5) When transporting and placing completed concrete piles, large transport equipment and driving equipment were required due to their weight, but with the construction method of the present invention, concrete piles made of metal or resin can be Since a hollow pipe is used as the main body of the pile, it is light and easy to carry and drive, and has good workability.

(6) There is no need for formwork, etc. to manufacture the piles, and they can be manufactured at low cost because they can be constructed on-site.

[Brief explanation of the drawing]

Figures 1A, B, and C are explanatory diagrams showing the conventional friction pile fixing method, Figure 2 is a front view of the pile body used in the method of the present invention, Figure 3 is a bottom view of the same, and Figure 4 is the pile tip metal fitting. Figure 5A is a perspective view of the pile body with the pile tip fitting attached to the tip of the pile body and is about to be driven into the soil, and Figure B is a diagram showing the pile body being driven into the soil at the desired depth with an expansion agent applied. Figure 6 shows several parts of the pile body enlarged by the expansion agent. 5...Pile body, 5a...Pile body tip, 5b...
Pile main body middle, 6a, 6b, 6c... slit, 7
... Pile tip metal fitting, 8... Expansion agent.

Claims (1)

[Claims] 1. A pile consists of a hollow pile body with a plurality of slits formed at several points around the tip and middle, and a pile tip fitting that closes the tip opening of the hollow pile body. After blocking the section with a pile tip metal fitting, the pile body is driven into the soil from the pile tip metal fitting to the desired depth, and after that, an expansion agent is put into the pile body, and over time, A pile fixing method characterized in that the slit portion formed at the tip of the pile and in the middle of the pile body is enlarged at multiple locations.