JPS60242217A - Formwork for pile head - Google Patents

Abstract

PURPOSE:To easily obtain the head of a pile by providing a tube which prevents the intrusion of soil cement by pressingly contacing with the inner surfacae of a pile by expansion caused by injection of a fluid on the outside of a cylinder with tapered face. CONSTITUTION:A tube 3 contracted in such a way as to position a coupling portion upwards and a cylinder 2 with a tapered face 1 are fitted on the head of a concrete pile B. Air or a liquid is injected into the tube 3 to cause it to expand so that the tube 3 is pressingly contacted with the inner surface of the pile B to set a formwork A for the head of pile. Cement milk and excavated soil are mixed together with stirring to form a soil cement column, and while the soil cement column is unhardened, the pile B is penetrated into an excavated pit C. The head of the pile is excavated, air is discharged from the tube 3 to cause the tube 3 to contract, and the coupling portion 4 is pulled to draw out the formwork A.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention relates to pile cap formwork for concrete piles.

(2) Conventional technology To create a footing, an auger screw is used to excavate from the ground to a predetermined depth underground, and during excavation, bentonite is mixed using a through hole provided in the axis of the auger screw. A hole is drilled while injecting a self-hardening mill such as a cement mill, and the mill and the excavated soil are stirred and kneaded to create a soil cement pillar underground. Insert and bury concrete piles.

At this time, since the head of the concrete pile is buried at the same level as the ground or below the ground, soil cement fills the hollow part of the concrete pile and hardens over time.

After scraping out the soil cement that has filled the hollow part of the concrete pile for about 1/2 meter or more from the head end of the concrete pile, and carefully cleaning it, pour fresh concrete into the hollow part of the concrete pile to connect the footing. It is being poured.

(3) Problems to be solved by the invention Since soil cement is removed after a number of days have passed after the concrete pile is buried, the soil cement filling the hollow part of the concrete pile can be easily removed. I rarely had problems that I couldn't do.

In addition, since soil cement is firmly attached to the inner periphery of the hollow part, there is the problem that it takes time and effort to completely remove the soil cement without adversely affecting the bond between the freshly poured concrete and the concrete pile. there were.

(4) Means for Solving the Problems In order to solve the above problems, the present invention provides a cylindrical body having a tapered surface on its inner periphery to facilitate upward pulling;
A pile cap formwork is constructed of tubes that are attached to at least the upper and lower ends of the outside of this cylindrical body, and that are inflated when air or liquid is injected to press against the inner periphery of the concrete pile.

(5) Function This invention creates a fill cement column in a bored hole by stirring and kneading excavated soil with a self-hardening mill, and then inflates a tube inside the head end of the above-mentioned drilled hole to cap the pile. Insert and bury concrete piles with formwork set.

After the soil cement has hardened, the air and liquid in the tube are discharged, the pile cap formwork is pulled out, and the tapered column remaining inside the concrete pile head is crushed and removed, and a layer of soil cement is applied to the inner circumference of the pile cap. Sand with a material that has a recess that will not prevent sanding.

(6) Examples In FIG. 1 and the Cancer λ diagram, A is the pile head formwork.

The above pile head type #A has a tapered surface 1 on the inner circumference that facilitates upward pulling. a tube 3 that can be injected and discharged with air or liquid to at least the upper and lower ends of the outer periphery of the cylinder 2, and that presses against the circumference of the concrete pile when inflated; and a pull-out retaining part 4.

Although the tubes 3 described above are provided along the entire outer length of the cylinder body 2 in the illustrated case, they may be provided only at the upper and lower ends of the cylinder body 2, and may have a structure in which the upper and lower tubes are connected by a bypass pipe.

In addition, in the illustrated case, the retaining part 4 is composed of a plate-shaped body 5 that is integrally provided within the upper end of the cylinder body 2 so as to cross the center thereof, and a through hole provided in the center of this plate-shaped body 5. Although the wire or hook inserted into the through hole 6 is engaged and pulled out by pulling, other structures may be used.

Furthermore, the air and liquid are injected and discharged through the tube 3.
Although a spout 7 with a stopper 8 is provided on the top wall of the mouth, other structures may be used.

Note that the cylindrical body 2 is made of synthetic resin, metal, or the like.

The pile head formwork according to the present invention has the above-mentioned configuration, and the method of use will be explained below. First, an auger screw is used to excavate from the ground to a predetermined depth underground, and during excavation, the auger screw Using the through hole provided in the shaft core, the hole is drilled while injecting self-hardening milk such as cement mill mixed with bentonite, and the mill and the excavated soil are stirred and kneaded to form a soil-cement pillar underground. After creating the
A concrete pile B is inserted into the drilled hole C while the fill cement column is not yet hardened.

At the head end of the concrete pile B of the above-mentioned inserted and buried IJ, the tube 3 and the cylindrical body 2, which have been contracted so that the retaining part 4 is on the upper side, are mounted low, and then the tube 3 is injected with air or The tube 3 is inflated by injecting liquid, and the tube 3 is pressed against the inner peripheral surface of the concrete pile B, and the pile cap formwork A is set at the head end of the concrete pile B.

When the concrete pile B is inserted and buried in the drilled hole C, soil cement fills the inside of the body 2, and between the concrete pile B and the pile head formwork A, p soil cement enters through the tube 3. thwarted.

After the burying work of the concrete pile B is completed, the pile head is excavated and the air or liquid inside the tube 3 is discharged to contract the tube 3, and then the retaining part 4 is pulled. Pull out the pile head formwork A.

The tapered column remaining within the head end of concrete pile B due to the above-mentioned pulling out will be crushed upward from the chain line E in the diagram with a shovel or the like and removed.

Then, concrete is poured and a footing D is provided as shown in Figure 3.

At this time, poured concrete flows into the head end of the concrete pile B.

(7) Effects As described above, when the pile cap formwork according to the present invention is pulled out, a tapered column is formed within the head end of the concrete pile that does not adhere to the inner wall of the head end at all. Moreover, it can be quickly crushed and removed.

Furthermore, since the inflated tube prevents soil cement from entering between the concrete pile and the pile cap formwork, time-consuming spacing can be omitted.

Furthermore, it is economical to reuse the pile head formwork that has been pulled out, as it can be reused.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional front view of a pile cap form according to the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a partially cutaway front view with a footing provided. A...Pile head formwork, 1...Tapered surface, 2...Cylinder body,
3...Tube, 4...Retaining part, 7... Mouthpiece, 8
...Applicant for the plug patent: Otodo Enoki, Hiroshi Enoki, Fumito Enoki, agent: Kama 1) Bun 2

Claims (1)

[Claims] A cylindrical body has a tapered surface on the inner circumference that makes it easy to pull out upwards, and the outside of this cylindrical body is inflated by injecting air or liquid at least at the top and bottom ends, and the fill cement enters while being pressed against the inner circumference of the concrete pile. A pile cap formwork consisting of a tube provided to prevent the air or liquid from being removed and to discharge the injected air or liquid, and a pull-out retaining part provided at the upper end of the cylindrical body.