JP2506398B2 - Construction method of cast-in-place concrete pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is to form a pile hole in the ground by excavation while pouring a stabilizing solution into the pile hole, and put a reinforcing bar basket inside the pile hole to form the pile. The present invention relates to a method for constructing a cast-in-place concrete pile in which concrete is placed in a hole.

[Conventional technology]

Conventionally, as shown in FIG. 3 (a), a pile hole (3) is excavated and formed in the ground (2), and a stabilizing solution (4) such as bentonite slurry is added to stabilize the hole wall. Reinforcing bar basket (5) is immersed in (4) and pile hole (3)
Then, concrete (11) is poured into the whole pile hole (3), as shown in the whole Fig. 3 (b).
It was building a columnar cast-in-place concrete pile.

[Problems to be Solved by the Invention]

However, if the area of the peripheral surface and the bottom surface is increased in order to increase the bearing capacity of the pile, the volume of the pile hole (3) becomes extremely large, and the amount of concrete (11) to be placed becomes enormous, resulting in high cost. There was a drawback.

The purpose of the present invention is to make it possible to greatly reduce the required amount of concrete in spite of enlarging the area of the peripheral surface and the bottom surface to obtain a strong supporting force, and moreover, the construction becomes troublesome. In addition, there is a point to devise so as not to cause an inconvenient situation in which the strength of the pile is significantly reduced.

[Means for solving the problem]

The characteristic means of the present invention is to install a pipe with both ends open in a pile hole containing a stable liquid in a state of being positioned inside a reinforced basket, and to pour concrete into the pile hole above the lower end of the pipe. It is to block the lower end of the pipe with the concrete, and then to pour the concrete on the outside of the pipe and to put the filler inside the pipe, and the effect is as follows. Is.

[Action]

In other words, the pipe is installed inside the pile hole, and the concrete is placed only on the outside of the pipe where the cage is installed.Therefore, the diameter of the pile hole should be large and the circumference and bottom of the pile should be large. However, by appropriately setting the diameter of the pipe in accordance with the required strength of the pile, the required amount of concrete can be greatly reduced and the cost can be sufficiently reduced.

By the way, if concrete is prevented from flowing into the pipe from the lower end when pouring the concrete, it is possible to cover the lower end of the pipe, for example, but the pipe will settle against the buoyancy in the pile holes containing the stabilizing liquid. The problem that a large amount of expense, labor, and construction period are required for construction is generated, and it is practically impossible to achieve sufficient cost reduction.

However, according to the present invention, after installing a pipe with both ends open in a pile hole containing a stable liquid, concrete is poured into the pile hole to a position above the lower end of the pipe, and the high viscosity of the concrete causes the pipe to Closing the lower end and then placing concrete on the outside of the pipe to prevent a large amount of concrete from flowing into the pipe, so the pipe can be installed easily and quickly without being adversely affected by the buoyancy of the stabilizing liquid. .

Furthermore, if the pile is to be provided with sufficient strength while the inside of the pipe is emptied, the pipe must have a large wall thickness and strength or a small diameter to achieve cost reduction. There are obstacles, and conversely, if importance is placed on achieving cost reduction, reliability in terms of strength will be adversely affected.

However, according to the present invention, for example, a filling material such as residual soil, sand, and crushed stone is put into the pipe, so that the pipe has a relatively low strength and a large diameter to sufficiently achieve cost reduction, and sufficient pile strength. Can be obtained in a reliable condition.

〔The invention's effect〕

As a result, the cost required for constructing the pile can be greatly reduced while the bearing capacity and strength of the pile are sufficiently increased, and the construction work is not troublesome, and the cast-in-place concrete pile is more economically advantageous. The construction method was completed.

〔Example〕

 Next, examples will be shown.

As shown in FIG. 1 (a), a pile hole (3) is excavated and formed in the ground (2) with a ground drill (1) in a state where the pile hole (3) has a substantially equal diameter over a whole length and a cross section has a substantially circular shape. A stabilizing solution (4) such as bentonite slurry is injected into the pile hole (3) to prevent the hole wall from collapsing.

As shown in Fig. 1 (b), a substantially cylindrical reinforcing bar basket (5) is installed in the pile hole (3), and a pipe (6) made of spiral steel or resin with both ends opened is piled. It is installed in the hole (3) so as to be located substantially concentrically inside the reinforcing bar basket (5).

The reinforcing bar basket (5) and the pipe (6) may be inserted into the pile hole (3) at the same time or separately.

As shown in FIG. 1 (c), the tremie pipe (7) is inserted between the reinforcing bar basket (5) and the pipe (6), and the tremie is inserted into the pile hole (3) above the lower end of the pipe (6). Placing concrete (8) with pipe (7), and then concrete (8)
The lower end of the pipe (6) is closed by solidification of.

As shown in FIG. 1D, concrete (9) is placed on the outside of the pipe (6) with the tremie pipe (7), and the filler (10) such as residual soil, sand and crushed stone is piped (6). )
The stabilizing liquid (4) discharged from the pile hole (3) is collected inside the pile, and as shown in FIG. 1 (e),
Concrete (9) is poured to the upper end of the pile hole (3), and the filler (10) is charged to the upper end of the pipe (6),
Then, the concrete (9) is solidified to construct a cast-in-place concrete pile whose sectional structure is shown in FIG.

The timing of pouring concrete (9) and the injection of filler (10) may be the same or different.

[Another embodiment]

 Next, another embodiment will be described.

The shape of the pile hole (3) can be changed as appropriate, and the excavation method can be appropriately selected.

The kind of the stabilizing solution (4) and the injection timing can be appropriately selected.

The structure, shape, size, and number of the reinforcing bar baskets (5) can be freely selected, and a plurality of reinforcing bar baskets (5) may be concentrically provided.

The material, shape, size, and number of pipes (6) can be freely selected, and a plurality of pipes (6) may be arranged in parallel.

The method of placing concrete (8) and (9) can be changed as appropriate, and the tremie pipe (7) is inserted into the outside of the reinforcing steel basket (5) or the concrete (8) is placed to close the lower end of the pipe (6). When installing the tremie pipe (7) pipe (6)
It may be inserted in.

A partition plate to be placed on the concrete (8) that closes the lower end of the pipe (6) may be put in the pipe (6), and the filler (10) may be put on the partition plate.

[Brief description of drawings]

FIGS. 1 and 2 show an embodiment of the present invention, FIGS. 1 (a) to (e) are explanatory views of the construction procedure, and FIG. 2 is a transverse sectional view of a pile. FIGS. 3 (a) to 3 (b) are explanatory views of the construction procedure of the conventional method. (2) …… Soil, (3) …… Pile holes, (4) …… Stabilizer,
(5) …… Reinforcing bar basket, (6) …… Pipe, (8),
(9) …… Concrete, (10) …… Filler.

Claims (1)

(57) [Claims] 1. A pile hole (3) is formed in the ground (2) by pouring a stabilizing liquid (4) into the pile hole (3), and a reinforcing bar basket (5) is put inside the pile hole (3). A method for constructing a cast-in-place concrete pile in which concrete is placed in the pile hole (3), wherein a pipe (6) having open ends is provided in the pile hole (3) containing the stabilizing solution (4). It is installed in a state where it is located inside the reinforced steel basket (5), and concrete (8) is placed in the pile hole (3) above the lower end of the pipe (6) and the concrete (8) is used. A cast-in-place concrete in which the lower end of the pipe (6) is closed, then concrete (9) is placed on the outside of the pipe (6), and a filler (10) is put inside the pipe (6). How to build a pile.