JPS59173420A - On-site driving reinforced concrete pile and its construction - Google Patents

Abstract

PURPOSE:To avoid troubles with the performance of reinforced concrete piles even when the upper layer of the piles is housed in a covering cylinder by housing unsuitable upper concrete layer mixed with impurities in a precast concrete or steel cylinder fixed to the head of the pile. CONSTITUTION:An unsuitable upper concrete layer 7' mixed with impurities such as cut dust of concrete, bentonite fine powder, etc., having less than a given strength, is housed in a precast concrete or steel cylinder 2 fixed to the head of a reinforced concrete pile A. Since the performance of the head of the pile A is shared by the cylinder 2, no trouble with the given performance of the pile occurs even when the upper layer 7' of the concrete 7 is housed in a covering cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to cast-in-place reinforced concrete piles and methods of construction thereof.

Conventionally, the above-mentioned cast-in-place thermal concrete IJ-to piles are generally constructed by excavating at a predetermined location, placing cage-shaped reinforcing bars in the running pile hole, and gradually pushing up concrete from the bottom of the pile hole using a tremie tube. At the upper end (approximately 0.05 to 1 m), unsuitable concrete with a strength below the specified level and containing impurities such as the remaining layer of the drilling (slime) and fine particles of bentonite is concentrated. Approximately 0.5-1m above the head
Pile cap treatment is performed in which the concrete is formed as a high reinforcement area, and after hardening, the concrete in this reinforcement area is destroyed and removed using a rock drill or a concrete breaker. There were many disadvantages, such as a decrease in work efficiency due to labor, a rise in costs, the occurrence of noise and vibration pollution due to destructive work, and the occurrence of work-related diseases.

The cast-in-place reinforced concrete pile of the present invention accommodates an unsuitable upper layer of concrete containing impurities inside a precast concrete ring or steel cylinder fixed to the pile head, and improves the performance of the pile head using this cylinder. By paying for this, the performance of the pile will not be affected even if the upper layer is left in the pile without being removed.

The method for constructing cast-in-place concrete piles of the present invention involves fixing a precast concrete ring or a cylindrical body made of flA to the upper part of a cage-shaped reinforcing bar, and inserting this reinforcing bar into a pile hole so that the upper end of the cylindrical body is aligned with a predetermined pile cap surface. Concrete is gradually pushed up from the bottom of the pile hole, and all of the unsuitable upper layer mixed with Q impurities such as slime and atonite is contained inside the cylinder. Therefore, the conventional pile cap treatment is made by hand, and the above-mentioned drawbacks associated with the pile head treatment are all solved in one fell swoop.

In the following, regarding the illustrated embodiment, first a cast-in-place reinforced concrete pile A will be explained, and then a method for constructing the same will be explained.

The cast-in-place reinforced concrete pile A is constructed in a pile hole 1 excavated at a predetermined position, as shown in FIG. 1, and has a cylindrical body 2 fixed to the pile head.

The cylindrical body 2 has a plurality of vertical bars 3 arranged in a circular shape and a ring-shaped horizontal bar 4.
It has a cylindrical shape of a precast concrete ring with cage-shaped reinforcing bars 5 connected to each other, and a guide surface 6 that is inclined inwardly and upwardly is formed in the lower part, and each vertical bar 3 protrudes from the upper and lower end surfaces by a certain length. There is.

Then, the lower protruding portion 3a of the vertical reinforcement 3 is connected to the vertical reinforcement 9a and the horizontal reinforcement 9b of the cage-shaped reinforcement 8 buried in the concrete 7 cast in the pile hole 1 of the cylindrical body 2tI'i in a lap joint, In addition, approximately the lower half part is fixed to the concrete 7, and the upper layer part 7' is unsuitable because it has a strength below a predetermined strength and is contaminated with impurities such as the remaining layer of the concrete 7 (slime) and fine particles of bentonite. is housed in the inner center of this cylinder 2.

Therefore, in the cast-in-place reinforced concrete pile A, since the performance of the pile head is borne by the cylinder body 2, there is no problem with the required performance of the pile even if the upper layer 7' of the concrete 7 is accommodated. The upper protruding portion 3b of the vertical reinforcement 3 of the cylinder body 2 can be used for connection with an upper structure (not shown).

Next, to explain the construction method of the cast-in-place reinforced concrete pile A, the lower protrusion 3a of the vertical reinforcement 3 of the cylinder body 2 is tied to the upper part of the vertical reinforcement 9a and the horizontal reinforcement 9b of the cage type reinforcement 8 in a lap joint. The cage-shaped reinforcing bars 8 are placed in the pile hole 1 so that the upper end of the cylinder body 2 coincides with a predetermined pile cap surface.

After that, a tremie pipe (not shown) is inserted to the bottom of the pile hole 1, concrete 7 is poured out, and the tip of the tremie pipe is gradually poured while keeping it buried in the concrete that has already been poured. East, the normal concrete 7 is poured from the lower end of the cylinder 2 to the inner surface of approximately the lower half, and the unsuitable upper layer 7' containing impurities is accommodated inside the upper side of the cylinder 2. .

In this case, the upper layer 7' is easily guided inside the cylinder 2 by the guide surface 6 and rises, and the upper layer 7'
Since the piles are not scattered while being housed in the cylinder 2, there is no need to perform conventional pile head treatment at all. ,#
A moxibustion cylinder may be used, and the shape and dimensions of the cylinder must be such that it can adhere to normal concrete according to the pile to be constructed, and accommodate all possible unsuitable upper layers. It is clear that this is a good thing.

As is clear from the above description, according to the cast-in-place reinforced concrete pile of the present invention, a precast concrete ring or a copper cylinder is fixed to the pile head.
Since this cylindrical body takes over the performance of the pile head, even if an unsuitable upper layer containing concrete impurities is housed inside the cylindrical body, the required performance of the pile will not be affected.

Further, according to the method for constructing cast-in-place reinforced concrete piles of the present invention, the upper end of the cylinder fixed to the upper side of the reinforcing bars is placed so that it coincides with the predetermined pile cap surface, and the concrete is poured and the impurities are removed. By storing the mixed and unsuitable upper layer concrete inside the cylinder, it is possible to accurately and accurately form cast-in-place reinforced concrete piles that meet the specified pile cap height formula without performing conventional pile cap treatment. It is easy to construct, and since the upper layer is not removed, there is no need for conventional pile cap treatment, which naturally reduces work efficiency, increases costs, causes noise and vibration pollution, and reduces labor costs. Disadvantages such as the occurrence of various diseases can be eliminated all at once.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Figure 1 is a longitudinal cross-sectional view of the main part of a cast-in-place reinforced concrete pile with a precast concrete cylinder fixed to the pile head; It is a partially cutaway perspective view showing a state in which it is fixed to a type reinforcing bar. 2... Cylindrical body made of precast concrete, 7...
Concrete, 7'... Upper layer, 8... Cage type reinforcement, -1... Pile hole. Figure 2

Claims (1)

[Scope of Claims] 1. An unsuitable upper layer contaminated with impurities due to concrete casting of cast-in-place concrete piles inside a cylinder made of precast concrete or T'i steel fixed to the head of the pile. Contains concrete and piles. 2. Fix a cylindrical body made of precast concrete 1 Note or fJi to the upper part of the cage-shaped reinforcing bar, and force the 1-shaped reinforcing bar into the pile hole to match the upper end force of the cylindrical body (predetermined pile cap ■). Gradually push up the Conch 1 Note from the bottom of the pile hole until the unsuitable Conk 1 Note in the upper layer containing impurities is accommodated inside the cylinder. A method for constructing a cast-in-place reinforced concrete pile, characterized by: