JP2848212B2 - Cast-in-place concrete pile method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cast-in-place concrete pile method in which the rigidity of a pile tip ground is improved.

[0002]

2. Description of the Related Art As a method of casting a cast-in-place concrete pile, a drilling fluid such as a stabilizing solution or muddy water is injected by an earth drill, an all casing, a reverse construction method, etc. to prevent collapse of a hole wall and abnormal loosening of a tip ground. It is a common practice to excavate a pile hole while inserting a steel cage into the pile hole, and then place underwater concrete with a tremy tube.

[0003]

Although the conventional construction method uses a drilling fluid, the ground around the pile hole, particularly the ground at the bottom of the pile hole, is loosened when excavating the pile hole. Slime remains at the bottom and accumulates. (During excavation, slime was removed thoroughly but could not be completely removed. Also, when slime was solidified by injecting a consolidation liquid at the end of excavation, slime settled and deposited on it before the underwater concrete was poured. If underwater concrete is poured into the pile hole in this state, the underwater concrete cannot penetrate into the ground, so that the loose ground cannot be firmly solidified and does not integrate with the slime. As a result, a cast-in-place concrete pile is created while leaving weak points in the ground at the tip of the pile, and the ground rigidity at the tip of the pile is small, and the deformation before reaching the ultimate bearing capacity is increased.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to improve the above-mentioned drawbacks of the conventional method, and injects cement milk which can penetrate into the tip ground of a loose pile into the tip ground. The purpose is to increase the rigidity at the tip of the cast-in-place concrete pile by solidifying the loose ground and integrating it with the pile concrete while solidifying the slime that accumulates and integrating it into the pile concrete.

That is, the present invention provides (A) a step of drilling a pile hole in the ground while injecting a drilling fluid, (B) a step of inserting and installing a reinforced cage in the pile hole, and (C) a tip of the tremy pipe. Inserting and installing a tremy tube with the injection pipe branching around it around its side in the pile hole, and pressing cement milk into the pile hole bottom from the injection pipe, (D) Pile hole by the tremy pipe A method of casting concrete underwater into a concrete pile, starting with placing the submerged concrete into the interior, continuing the casting while pulling up the tremy pipe with an injection pipe, and placing it to the pile head.

The gist of the present invention is that, at the time of insertion and installation of a tremy tube into a pile hole, an injection tube whose distal end is branched so as to surround the periphery of the tremy tube is attached to the side of the tremy tube. The point is that the pipe is inserted to the bottom of the pile hole in the same way as the tremy pipe, and cement milk is injected into the ground at the tip of the pile using the injection pipe shortly before the underwater concrete is poured by the tremy pipe. The injected cement milk penetrates into the loose ground and hardens, and is integrated with the pile concrete that is cast after solidifying the ground, and at the same time, the slime is also integrated with the pile concrete that is cast after the solidification.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view showing the construction process of the present invention. The construction procedure of the present invention will be described with reference to FIG.

(1) The ground is excavated to a predetermined depth by an excavator while pouring the excavating liquid 2, and the pile hole 1 is drilled.
(FIG. 1A) (2) Insert the reinforcing bar 3 into the pile hole 1. (Figure 1
(B)) (3) While attaching the injection pipe 4 to the tremy pipe 5, insert both of them into the pile hole 1 until the tip reaches the pile hole bottom.
The injection tube 4 is a steel tube or a plastic tube, and is attached to the tremy tube 5 while being connected by screws cut at both ends. A small hole is bored at the tip of the injection pipe 4 with a different direction so that the cement milk to be pressed can be uniformly pressed into the bottom of the pile hole. (Fig. 1 (c)) (4) Cement milk 7 is poured into the ground at the bottom of the pile hole by the injection pipe 4.
Press-fit. (FIG. 1 (d)) (5) Pour of underwater concrete into the pile hole 1 from the tremy tube 5 is started. Pouring is continued while pulling up the tremy pipe 5 and the injection pipe 4 to the pile head. (Figure 1
(E)) After that, the pile head processing is performed as usual, and the construction of the pile is completed.

FIG. 2 shows an example of a structure in which the injection tube 4 is attached to the tremie tube 5, (a) is a vertical sectional view, and (b).
(A) is a view taken along the line AA, and (c) is a view taken along the line BB in (a).

In this example, one-way metal fittings 9 and three-way metal fittings 10 made of several steel plates are used to connect the tremy tube 5 and the injection tube 4 by bolting them around the periphery thereof. In this example, at the tip, the injection pipe 4 is branched into three so as to surround the tremie pipe 5, and at the tip of each injection pipe 4, a multi-directional small hole 11 is drilled. The uniform injection of the cement milk 7 is achieved. The more the number of branches of the injection tube 4, the more uniform injection can be achieved, but usually the number of branches is about three or four. When it is necessary to connect the injection pipe 4, it is connected by screws 8 cut at both ends.

[0012]

According to the present invention, cement milk which can penetrate into the loose ground at the tip of the pile is poured into the ground at the tip as uniformly as possible, so that the loose ground is integrated with the pile concrete while firmly solidifying and remains together. Since the slime can also be solidified and integrated into the pile concrete, the ground rigidity at the tip of the cast-in-place concrete pile can be increased.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a construction step of the present invention.

FIGS. 2A and 2B show an example of a structure in which an injection pipe 4 is connected to a tremie pipe, wherein FIG. 2A is a vertical sectional view, and FIG.
FIG. 2A is a view as seen from the direction of the arrow A, and FIG.

[Explanation of symbols]

1. Pile hole, 2. Drilling fluid, 3. Reinforcing cage, 4. Injection pipe, 5. Ptolemy pipe, 6. Concrete, 7. Cement milk, 8. Screw, 9. One side Connection hardware, 10
..Three-way connection hardware, 11...

Claims (1)

(57) [Claims] (A) a step of drilling a pile hole in the ground while pouring a drilling fluid; (B) a step of inserting and installing a reinforcing cage in the pile hole; and (C) a form in which the tip surrounds the periphery of the tremy tube. Inserting a tremy tube with an injection pipe branched at the side into the pile hole and installing it in the pile hole, and pressing cement milk from the injection pipe into the bottom of the pile hole, (D) submerging into the pile hole by the tremy tube A cast-in-place concrete pile method consisting of starting concrete placement, continuing the placement while pulling up the tremy tube with an injection pipe, and placing it to the pile head.