JPH01250524A - Facility construction method for soil cement synthetic steel pipe piles and steel pipe piles used in the construction method - Google Patents

Abstract

PURPOSE:To certainly reinforce a pile head section, by setting a ring-formed concrete layer on the outer peripheral section of a steel pipe column set in a cement column, in a state that the concrete layer is continuously set at the upper end of the soil cement column formed in a vertical slot, at the upper end section of the vertical slot. CONSTITUTION:By an auger, through ground 4, a vertical slot is bored and cement milk is injected therein, and a soil cement column 2 is formed, and before the cement column 2 is hardened, a steel pipe pile 1 is inserted in the cement column 2. After that, at the upper end section of the vertical slot, a ring-formed prefabricated concrete layer 3 is set fitted externally on the head section of the pile 1 in a state that the layer 3 is mounted on the upper end of the cement column 2. After that, a space between the concrete layer 3 and the pile 1 is filled up with mortar or concrete 5.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a soil cement composite steel pipe pile facility in which a vertical hole is formed in the ground and a steel pipe pile is arranged inside a soil cement column formed in the vertical hole. Concerning construction methods and steel pipe piles used in the construction methods.

[Conventional technology]

Conventionally, in the construction method for soil-cement composite steel pipe piles as described above, in order to reinforce the head of the steel pipe pile, the internal soil cement in the head of the steel pipe pile is removed and concrete is poured inside the head of the steel pipe pile to replace it. There was a method for filling (for example, see Japanese Patent Publication No. 61-22089).

[Problem to be solved by the invention]

However, in the conventional method described above, the cross-sectional area of the reinforcing filled concrete layer is only equal to the opening cross-sectional area of the steel pipe pile, which limits the reinforcement strength, and there is still a problem that sufficient reinforcement cannot be achieved. Ta.

An object of the present invention is to more reliably reinforce the pile head through rational improvements.

[Means to solve the problem]

The characteristic means of the soil cement synthetic steel pipe pile construction method according to the present invention is that, in contrast to the basic method of forming a vertical hole in the ground and arranging the steel pipe pile inside the soil cement column formed in the vertical hole, the vertical hole is An annular concrete layer is attached to the outer periphery of the steel pipe pile at the upper end so as to be connected to the upper end of the soil cement column, and its functions and effects are as follows.

[For production]

That is, since the reinforcing concrete layer is attached and formed on the outer periphery of the steel pipe pile, the cross-sectional area of the reinforcing concrete layer can be secured to be larger without any limit, compared to forming a concrete layer inside the steel pipe pile.

〔Effect of the invention〕

As a result, the reinforcement strength of the head of the soil-cement synthetic steel pipe pile could be made sufficient, and the strength of the pile against earthquakes and the like could be greatly improved.

In addition, by ensuring a large cross-sectional area of the strong portion at the upper end of the pile, the support strength for the upper structure can also be improved.

Furthermore, with conventional construction methods, when the steel pipe pile is made thinner, the reinforcement strength also decreases, resulting in a significant drop in pile strength, but with the construction method of the present invention, the steel pipe pile can be made thinner while ensuring sufficient reinforcement strength. In this respect, it is also advantageous in terms of cost reduction due to the small diameter holes of steel pipe piles.

[First example] Next, a first embodiment will be described.

Figure 1 shows soil-cement synthetic steel pipe piles used as the foundations of various above-ground structures, where (1) is a steel pipe pile, (2) is a soil-cement column, and (3) is a reinforcing concrete layer.

As for the facility construction method, first, cement milk is injected while drilling a vertical hole in the ground (4) with an auger, a soil cement column (2) is formed in the vertical hole, and the soil cement column (2) is hardened. Before this, the steel pipe piles (1) are inserted and installed concentrically inside the soil cement columns (2).

After that, at the upper end of the vertical hole, the ring-shaped ready-made concrete layer (3) is placed on the upper end of the soil cement column (2) and fitted over the head of the steel pipe pile (1). Place and then concrete layer (3) and steel pipe pile (1)
Fill the gap with mortar or concrete (5) to integrate the two.

In addition, it is preferable to use a pre-formed concrete layer (3) that has been prestressed using a PC steel rod or the like.

In addition, the head of the steel pipe pile (1) has many lips (
6) is attached, and with this, the concrete layer (3) filled with mortar and concrete and the steel pipe pile (1)
to ensure greater integration with the

[Second example] Next, a second embodiment will be explained.

Figure 2 also shows a soil cement synthetic steel pipe pile, but the construction method for this facility is to insert and install the steel pipe pile (1) inside the soil cement column (2), and then install the steel pipe pile (1) at the upper end of the vertical hole. 1) Fill the outer periphery of the head with concrete to form a reinforcing annular concrete layer (3) on site.

In addition, there are many ribs (6) on the outer peripheral surface of the head of the steel pipe pile (1).
At the same time, a flange (8) with a plurality of PC steel rods (7) erected thereon is attached in advance at a position corresponding to the bottom of the concrete layer (3).
After forming 3), a lifting load is applied to the PC steel bar (7) using the flange (9) placed on the upper end surface of the concrete layer (3) as a reaction force fulcrum, thereby causing the reinforcing concrete layer (3) to Gives prestress.

[Other Examples]

Next, other examples will be listed.

(a) When carrying out the soil cement synthetic steel pipe pile construction method according to the present invention, a steel pipe pile (1) to which a reinforcing annular concrete layer (3) is attached in advance may be used.

(0) Various improvements can be made to the specific integrated structure of the fal pipe shaft (1) and the concrete layer (3).

(c) When applying prestress to the concrete layer (3), various improvements can be made to the specific means and structure for applying prestress.

(=) Soil cement may also be filled inside the steel pipe pile (1). In that case, steel pipe piles (1
) may be formed with a reinforcing concrete layer not only on the outer periphery but also on the inside.

(n) The diameter of the reinforcing concrete layer (3) may be determined as necessary, and the vertical length dimension of the steel pipe pile (1
) may be determined as appropriate, taking into consideration the distribution characteristics of the bending moment.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the facility form shown in the accompanying drawings.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the present invention, and a second embodiment of the present invention is shown in FIG.
The figure is a sectional view showing a second embodiment of the present invention. (1)... Steel pipe pile, (2)... Soil cement column, (3)... Concrete layer.

Claims (1)

[Claims] 1. A soil cement composite steel pipe pile facility in which a vertical hole is formed in the ground (4) and a steel pipe pile (1) is arranged inside a soil cement column (2) formed in the vertical hole. A soil-cement composite steel pipe pile, which is a construction method in which a ring-shaped concrete layer (3) is attached to the outer periphery of the steel pipe pile (1) in a state that it is connected to the top end of the soil-cement column (2) at the top end of the vertical hole. facility construction method. 2. The annular concrete layer (3) is attached to the steel pipe pile (1)
A steel pipe pile for use in a facility construction method for a soil cement synthetic steel pipe pile according to claim 1, wherein the steel pipe pile is integrally attached in advance to the soil cement synthetic steel pipe pile.