JPH09242067A - Building method for cast-in-place concrete pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce labor and time required for the after work by utilizing a stand pipe (casing) as the form of a footing after completing a cast-ins place concrete pile. SOLUTION: A casing 12 is penetrated into the ground 10 so as to form a large diameter hole 14, and the ground is drilled from the bottom part of the large diameter hole 14 so as to drill a pile hole 16 of small diameter. Next, a partition cage 24 is arranged over the pile hole 16 in the casing 12, a reinforcement cage 22 is inserted into the pile hole 16 through the partition cage 24, and concrete 40 is placed in the pile hole 16 and the partition cage 24. During placing the concrete 40, inferior concrete such as laitance flows out through the net 32 of the partition cage 24. The concrete 40 overflowing the partition cage 24 is laid on the bottom of the large diameter hole 14, and the surface of concrete 40 is finished flatly. Hereby, after curing the concrete 40, a footing can be built by using the casing 12 as the form. Further a bulding frame main body can be succeedingly built.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a method for constructing a cast-in-place concrete pile.

[0002]

2. Description of the Related Art A large diameter hole is formed inside a cylindrical stand pipe that penetrates into the ground, and then a pile hole having a diameter smaller than that of the stand pipe is formed at the bottom of the large diameter hole, and a rebar cage is inserted into this pile hole. As a method of constructing cast-in-place concrete piles after placing the concrete, an inner casing is externally fixed to the rebar cage at the bottom of the large diameter hole, and bad concrete such as breathing and latance is overflowed from the inner casing and discarded. , JP-A-3-
It has been proposed in 158519.

[0003]

According to this method of constructing a cast-in-place concrete pile, the ceiling of the inner casing is aligned with the top of the concrete pile, so that the pile head is not required to be suspended. It is not possible to modify the movement of the reinforced cage inside. Moreover, since the inner casing is formed by processing an iron plate into a cylindrical shape, it is not easy to confirm whether or not defective concrete is completely discharged from the inside of the inner casing, and it is not possible to accurately judge the completion time of concrete placement. In addition, in order to install footing on cast-in-place concrete piles, work to excavate around concrete piles, work to lay rocks on the bottom of the excavation, and work to cast discarded concrete on rocks, Alignment work, casting concrete for footing, and backfilling work were required, and much labor and time were required to build the foundation of the building.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems, and can correct the position of a reinforcing bar during concrete placement, completely discharge defective concrete from a concrete pile, It is another object of the present invention to provide a method of constructing a cast-in-place concrete pile that can reduce the labor and time required for subsequent work by using a stand pipe as a footing formwork after completion of the cast-in-place concrete pile.

Specifically, in the method for constructing a cast-in-place concrete pile according to the present invention, first, a cylindrical casing is arranged in the ground and a large-diameter hole surrounded by the casing is formed. The casing may penetrate into the ground due to vibration or the like, or the surroundings of the casing may be backfilled after excavating the ground and disposing the casing. Next, the ground is drilled from the bottom of the large diameter hole, and a pile hole smaller in diameter than the casing is drilled. The drilling method includes a reverse method, an earth drill method, a Benoto method, and a BH method, and an optimum method is adopted according to ground conditions, various pile conditions, and the like. Next, a partition basket whose outer peripheral portion is surrounded by a net is placed above the pile hole in the large-diameter hole, and a reinforcing steel basket is placed in the pile hole via the partition basket. The partition basket is, for example, externally mounted on a reinforcing rod cage and temporarily fixed, and the reinforcing basket is inserted into the pile hole, and at the same time, the partition basket is seated on the bottom of the large diameter hole in the casing. At this time, the adjusting part of the partition basket may be fixed to the casing. Next, concrete is cast inside the pile hole and the partition basket. Concrete is poured in the same way as underwater concrete is poured using a tremy tube. When the concrete comes up to the partition basket, defective concrete such as latencies and breathing that have emerged on the surface of the poured concrete is discharged to the periphery through the net of the partition basket. Therefore, the inside of the partition basket is filled with high quality concrete while securing the cover. Defective concrete is discharged from the large-diameter hole by, for example, a sand pump. Next, concrete is laid inside the large diameter hole and outside the partition basket. For example, in the case of concrete having relatively poor fluidity, a heaped concrete on a partition basket may be dropped around the surroundings and spread. The spread concrete will be used as a waste concrete when the footing concrete is placed in the large diameter hole later. Next, the surface of the concrete in the basket and the surface of the concrete laid around the basket are finished flat. When the cast-in-place concrete pile is constructed as described above, after arranging reinforcing steel in the large-diameter hole as necessary, concrete is cast using the casing as a formwork,
This concrete can be the superstructure of the cast-in-place concrete pile (eg, footing, column, slab, underground wall, beam, pile head). Further, the skeleton body can be continuously constructed.

It is preferable that the partition basket and the reinforcing bar are connected so that the position of the reinforcing bar relative to the partition basket can be adjusted. In this case, it is preferable that each of the partition basket and the reinforcing bar has an adjusting portion extending near the top end of the casing, and that the adjusting portion can adjust the position of the reinforcing bar relative to the partition basket.

[0007]

As described above, according to the present invention, the casing is used as a formwork of the superstructure of the cast-in-place concrete pile, and the concrete laid in the large diameter pile is used as the waste concrete of the superstructure. As the cast-in-place concrete pile is completed, the process of removing the casing, placing the waste concrete for footing, excavating and backfilling the surrounding ground, assembling and dismantling the formwork is not required after the completion of the cast-in-place concrete pile, and the construction cost is significantly reduced. At the same time, pollution problems such as noise and vibration generated by these operations are eliminated. In addition, by allowing the position of the reinforcing bar cage to be adjusted near the top end of the casing, it is possible to easily correct the reinforcing bar cage that has been moved during the placement of concrete. Furthermore, since defective concrete such as slime and breathing generated during concrete casting is completely discharged from the concrete pile through the net of the partition basket, the completed concrete pile can be given a predetermined strength, and It can be confirmed by visually observing the concrete in the partition basket through a net whether or not the water has been completely discharged.

[0008]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the process of constructing a cast-in-place concrete pile according to the present invention. In this method, first, a cylindrical casing 12 is embedded in the target ground 10, and a large diameter hole 14 is formed inside the casing 12 (FIG. 1A). The casing 12 is determined by the size and shape of a footing (not shown) constructed on a reinforced concrete pile. For example, a circular footing is a cylindrical casing, and a rectangular (eg, a square or hexagonal) footing is supported. A rectangular casing is used. When the heads of a plurality of cast-in-place concrete piles are connected by one footing, a rectangular, oval (ie, truck-shaped) casing is used. The method of embedding the casing 12 and the method of forming the large-diameter hole 14 can be selected variously according to the ground conditions and the like. When the ground 10 is a sand layer or a soft silt layer, the ground 10 is penetrated by applying vibration with a vibrator or the like, and then the casing 10 May be excavated and discharged, or after excavating the ground 10 to a predetermined depth, the casing 12
May be arranged in a predetermined position, and the periphery thereof may be backfilled with earth and sand.

Next, a hole 16 having a diameter smaller than that of the casing 12 is formed by drilling a hole from the bottom of the large diameter hole 14 to a predetermined depth (FIG. 1B). The drilling method is the earth drill method,
From the reverse method, the Benoto method, the BH method, and the like, an appropriate method is selected according to various conditions such as a drilling depth and a pile diameter.
Further, a drilling machine 18 corresponding to the above-described method is used. When the earth drilling method, the reverse method, and the BH method are adopted, the ground shaved while circulating the stable liquid 20 containing bentonite in the large diameter hole 14 and the pile hole 16 to protect the hole wall during the drilling. The earth and sand is discharged by an appropriate method. However, when the Venoto method is employed, it is not necessary to use a stabilizer.

When drilling is completed to a predetermined depth, the drilling machine 18
From the pile hole 16. Next, the cylindrical rebar cage 22 manufactured in a size corresponding to the pile hole 16 is inserted into the pile hole 16 (FIG. 1 (c)). A partition basket 24 is attached to the upper part of the reinforcing basket 22. The bottom of the partition basket 24 is seated on the bottom of the large-diameter hole 14, and the reinforcing basket 22 is arranged at a predetermined height. In order to accurately define the height of the partition basket 24, a support portion (not shown) of the partition basket 24 may be provided at the bottom of the large-diameter hole 14, or the adjusting portion 29 of the partition basket 24 may be provided in a casing. 12 may be fixed by welding. In addition, as shown in FIG. 5, when the inner casing 50 is installed in the pile hole 16 depending on the situation, the adjusting portions 29 and 35 of the partition basket 24 and the reinforcing basket 22 are
It may be tied to the hook-shaped member 50 hooked on the head of the inner casing 50.

As shown in FIGS. 2 (a) and 2 (b), the partition basket 24 has a plurality of hoops 26 formed to have substantially the same diameter as the inside diameter of the pile hole 16, A plurality of vertical streaks 28 arranged and connected at equal intervals; a plurality of spacers 30 arranged at equal intervals inside the hoop streaks 26;
The vertical streaks 28 are composed of a net 32 or lath arranged so as to surround the periphery of the hoop streaks 26,
A predetermined length is extended upward from the end to form an adjusting section 29. Then, as shown in FIG. 2B, the reinforcing basket 22 is provided inside the partition basket 24 using the spacer 30 as a guide.
2 vertical streak, ie, the upper end of the main streak 34, ie, the adjusting portion 35
Is connected to the adjusting section 29 of the partition basket 24 by a connecting means 36 as appropriate (see FIGS. 1C and 1D). In addition, the steel cage 22
And the partition basket 24 are combined with the casing 1
2 or the partition basket 24 is first set in the casing 12, and then the reinforcing basket 22 is inserted into the partition basket 24.
May be furnished.

Returning to FIG. 1, after the rebar basket 22 is inserted into the pile hole 16, the tremy tube 38 is inserted into the pile hole 16, and concrete 40 is poured in the same manner as underwater concrete (FIG. 1 ( d)). At this time, the distance between the reinforcing cage 22 and the hole wall of the pile hole 16, that is, the covering of the concrete is determined by
An appropriate value is secured by the spacer 30 of No. 4. When the surface of the concrete 40 rises to near the top end of the partition basket 24, the defective concrete 41 such as latence or breathing floating on the surface of the concrete basket 24 becomes a part of the partition basket 2.
4 is discharged to the periphery thereof through the net 32 (see FIG. 3).
The discharged defective concrete 41 is discharged out of the casing 12 by a sand pump 44 arranged in the large-diameter hole 14 (FIG. 1E). In addition, whether the concrete flowing out through the net of the partition basket 24 is the defective concrete 41 can be visually observed.

When the surface of the concrete 40 rises above the top end of the partition basket 24 and the concrete 40 overflows the partition basket 24, the placing of the concrete 40 is stopped. Also, concrete 40 is placed on the partition basket 24.
If there is a surplus part of this, concrete 4 of this surplus part
Drop 0 around. Next, when the reinforcing cage 22 moves during the placement of the concrete 40, the connection between the vertical bars 28 of the partition basket 24 and the main bars 34 of the reinforcing basket 22 is disconnected, and the positions and heights of the reinforcing basket 22 and the partition basket 24 are changed. Correct the etc. When the correction is completed, the reinforcing basket 22 is connected to the partition basket 24 again. Then, the top of the concrete 40 in the partition basket 24 and the surface of the concrete 40 overflowing around the partition basket 24 are leveled (FIG. 1F).

After a predetermined curing time, necessary reinforcing bars are arranged inside the casing 12, and as shown in FIG. 4, concrete is cast into the casing 12 as a mold to form a footing 46. In addition, the footing 46 is connected by an underground beam 48.

In the above embodiment, the casing 12 is used as the formwork of the footing 46. However, the structure constructed using the formwork inside the casing 12 includes columns, slabs, underground walls, Any of a beam and a pile head may be used. In addition, the partition basket 24 can be variously used in addition to the above-described application by changing the shape and the material to be used.
For example, it can be used as a general concrete formwork.

[Brief description of drawings]

FIG. 1 is a view showing a method for constructing a cast-in-place concrete pile according to the present invention.

FIG. 2 is a sectional view and a plan view of a partition basket.

FIG. 3 is a view showing a state in which defective concrete flows out of a net of a partition basket.

FIG. 4 is a sectional view showing a final shape of a cast-in-place concrete pile and a footing.

FIG. 5 is a diagram showing a method of constructing a cast-in-place concrete pile using an inner casing.

[Explanation of symbols]

10 ... ground, 12 ... casing, 14 ... large diameter hole, 16 ...
Piles, 20: Stabilizing liquid, 22: Reinforcing cage, 24: Partition basket, 2
9: adjusting member, 32: net, 35: adjusting member, 36: connecting means, 40: concrete.

Claims (5)

[Claims] 1. A step of: (a) disposing a tubular casing in the ground and forming a large diameter hole surrounded by the casing; (b) drilling the ground from the bottom of the large diameter hole to form the casing. A step of drilling a pile hole having a smaller diameter than that, (c) a step of arranging a reinforcing bar cage in the pile hole and arranging a partition basket surrounded by a net on the upper side of the pile hole, A method for constructing cast-in-place concrete piles, which includes the step of placing concrete inside the basket and discharging defective concrete outside the partition basket during the placing of concrete, and (e) finishing the surface of the concrete flat. . 2. The construction of a cast-in-place concrete pile according to claim 1, wherein after the step (e), concrete is placed in the large-diameter hole using the casing as a formwork, and the concrete is used as an upper structure of the cast-in-place concrete pile. Method. 3. The method for constructing a cast-in-place concrete pile according to claim 2, wherein the upper structure is any one of footing, pillar, slab, underground wall, beam and pile head. 4. The method for constructing a cast-in-place concrete pile according to claim 1, wherein the partition basket and the rebar cage are connected with adjusting members for adjusting them so that they are in predetermined positions. 5. The method for constructing a cast-in-place concrete pile according to claim 4, wherein each of the adjusting members is arranged near the top of the casing.