JP2000314131A - Pile head treatment method of concrete pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily remove a pile head after concrete is cured in a pile head treatment method wherein an extra portion of a pile head of a cast-in-place concrete pile is crushed and lifted to remove it, wherein air and/or liquid is injected under pressure into a separation device set on the boundary surface between the pile head and the extra portion thereof to vertically separate the concrete. SOLUTION: A separation device is set beforehand in a reinforcing bar cage A located on the boundary surface between an extra portion and a pile head portion of a concrete pile. Just after concrete is placed, air and/or liquid is injected under pressure into the device through a tube B connected thereto to provide a fragile layer in the concrete, and hence the extra portion can be separated without applying any force to the cured concrete. Thus, in the pile head treatment to remove an extra portion of the pile, noises and vibration are not generated and moreover a pile removal operation can be easily and economically performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of treating a pile head of a cast-in-place concrete pile (JP-A-61-257532, JP-A-62-117914, JP-A-64-6).
413, JP-A-5-67732, JP-A-5-67732.
-207661, JP-A-8-60653, etc.) relates to a method for easily removing an extra pile head portion from a pile top.

[0002]

2. Description of the Related Art In the cast-in-place concrete pile method, a reinforced cage assembled on site is inserted into a pile hole, and concrete is sequentially driven from the bottom to form a foundation pile. Since the low-quality layer and the latence layer are formed by entraining the muddy soil and muddy water generated at the pile bottom and in the middle of the pile, extra about 50 to 100 cm is added to the design pile length in advance in consideration of the safety of the pile head strength. Concrete is poured into the area (called extra part).

[0003] It is necessary to remove the excess pile for securing the predetermined strength up to the design pile length at the top of the pile after the concrete is hardened, and since this removal work is usually performed by a breaker or a call pick hammer, noise and noise are reduced. Vibration and dust generation were inevitable, and the work period was prolonged.

For this reason, piles that suppress noise, vibration, and dust, for example, by sucking and removing the excess portion before the concrete hardens, reducing the strength of the concrete after hardening, and injecting and splitting an expansive material. A head processing method has been proposed (see the above-mentioned publication).

However, in these methods, it is difficult to secure the level of the top of the pile, the strength of the concrete is reduced, and a large amount of manpower and equipment is required for the work. It was not possible to suppress noise and vibration, for example, because it had to rely on repairs made by the company, and did not satisfy the intended effects and work efficiency.

[0006]

Recently, the development of a crusher capable of crushing waste concrete on site with low noise has made it possible to reduce the amount of concrete transported outside the site and to recycle it. Is increasing.

Accordingly, the present invention provides a method of removing excess concrete by dividing it into large portions, and then crushing and recycling the material by using a crusher. The present invention has been created in order to provide a pile head treatment method that can achieve a predetermined design length and strength while economically treating the pile head.

[0008]

To achieve the above object, a method for separating excess concrete is to install a tube which needs a spray port in advance at a predetermined position to be a top of a reinforcing bar cage inserted into a pile hole. After the concrete is cast, the tube is extended to the ground and connected.
By injecting air and / or liquid into the concrete by injecting it under pressure and creating a layer between the pile top and the top of the pile, it can be largely divided without additional force after the concrete has hardened. It is one that can be separated and removed.

A tube for injecting air and / or liquid is installed on the outer periphery of the reinforcing bar in the pile hole, and the tube is extended to stretch the inside of the reinforcing bar in a triangular, polygonal or concentric manner. The air and / or liquid to be sprayed should be placed so that it is layered all over the surface and separated easily.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The object of the present invention is to roughly divide the conventional method of processing pile heads while generating noise, vibration and dust by human power with the advent of concrete crushers due to the improvement of technology. By crushing with a crusher and treating the inside of the yard, it is possible to simply and more economically provide a large-scale method of allocating a surplus portion of concrete to contribute to low noise, no dust, and recycling of construction waste.

[0011] Air and / or liquid is injected horizontally or upward into the concrete from injection ports provided as appropriate by pressurized injection from a tube set at a predetermined position on the outer periphery and inside of the rebar cage.

The tube is installed so as not to obstruct the insertion of the tremy tube for placing concrete, so as to avoid the central portion, and to keep the separation surface horizontal.

The tube to be installed is appropriately fixed to a reinforcing bar cage so that it does not move when concrete is poured or when air and / or liquid is injected under pressure.

The liquid to be injected under pressure is sprayed into concrete by using a concrete retarder, bentonite or a polymer polymer, an aluminum powder suspension or the like in addition to fresh water to chemically secure a separation layer.

[0015]

As described above, the present invention aims at suppressing the recycling of construction waste from outside the site and recycling it. The method can be performed very easily and economically.

[Brief description of the drawings]

FIG. 1 is a perspective view of a state in which a tube is installed on the outer periphery of a reinforcing bar cage.

FIG. 2 is a perspective view of a state in which a tube is installed inside a reinforcing bar cage.

FIG. 3 is an explanatory view of a state in which air and / or liquid is ejected from a tube.

FIG. 4 is a perspective view showing a state in which a disk-shaped cap also serving as a spacer on an outer peripheral portion of a reinforcing bar is installed.

[Explanation of symbols]

 A Reinforced basket B Pressurized injection tube C Compressor

Claims (3)

[Claims] 1. A fragile layer is formed in concrete by injecting air and / or liquid from a tube piped at a boundary between an extra pile portion and a pile top portion of a cast-in-place concrete pile, and a remaining layer after the concrete is hardened. A pile head treatment method characterized by facilitating removal of a pile. 2. A tube to be piped for separating concrete between the pile head excess portion and the pile top portion is made of a hollow material such as canvas, vinyl, plastic, rubber, or metal, and is provided with air and / or liquid. It has a jet port for jetting horizontally or upward. 3. The liquid to be jetted when separating the pile top margin and the pile top is made of concrete by using a concrete retarder, bentonite, a polymer polymer, an aluminum powder suspension or the like in addition to fresh water. The inside separating layer is further chemically secured.