JP6689591B2 - Pile cement extraction method and extraction tool - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for extracting cement in a pile and a extracting tool for forming vertical holes for establishing columns in the upper part of a concrete pile buried in the ground as a foundation of a building.

  A cylindrical paper tube is previously attached to the upper part of the hollow concrete pile, and the concrete pile is buried in the ground by the pile driving method, and uncured cement (a mud also called "Noro", "milk", etc.) (A mixture of cement and cement) has been solidified, the method of opening a vertical hole for establishing a pillar at the top of the concrete pile by lifting the paper cylinder with a digging heavy machine etc. and removing it from the concrete pile Are known.

Further, the pile cement removal tool shown in the following Patent Document 1 related to the applicant's application wraps the outer peripheral surface of the extraction tool body with a well-known aerated plastic film having a large number of small chambers in which air is enclosed, The extraction tool body is preset on the top of the concrete pile, the concrete pile is buried in the ground, and the plastic film intervenes when the extraction tool body is lifted after uncured cement is solidified. The extraction tool body is designed to be easily removed from the concrete pile, thereby facilitating the opening of the vertical hole for establishing the pillar.
Further, the device for extracting cement in a pile, which is disclosed in the following Patent Document 2 filed by the present applicant, is a hexagonal tubular assembly by detachably connecting three folded plate-shaped partition plates to each other at both side edges. And an air bag is arranged so as to cover the outer surface of each partition plate, the assembly is loaded into a concrete pile, and the air bag is inflated so that the assembly is placed in the concrete pile. It is to be set without gaps.

Japanese Examined Patent Publication No. 7-30548 Japanese Patent No. 3911065

By the way, in the cement extracting device for pile shown in Patent Document 1, since the bubble-containing plastic film does not sufficiently adhere to the inner peripheral surface of the concrete pile and a gap is formed, uncured cement may enter the gap. is there. For this reason, a cement layer is formed on the inner peripheral surface of the concrete pile after the extraction tool body is removed, and if it is left as it is, a cement layer having no strength will be interposed between the building pillar and the seismic resistance. There was a risk of loss of sex. There is a problem that it takes a lot of labor and time to cleanly remove the cement layer.
Further, the in-pile cement extraction tool disclosed in Patent Document 2 is intended to eliminate the above-mentioned gap by inflating the airbag, but for forming a hexagonal tubular assembly. Since the manufacturing cost of the partition plate and the air bag is high, there is a problem that it cannot be provided inexpensively like the paper tube extraction tool shown in Patent Document 1 and it cannot be disposable, and it is repeatedly used. In order to do so, it is necessary to cleanly remove the adhered cement, which is a problem in that it takes time.

  The present invention solves the above problems, provides a pile in-cement extraction tool that does not infiltrate uncured cement between the tool body and the inner peripheral surface of the concrete pile, and a cement layer on the inner peripheral surface of the concrete pile. By preventing the formation of the foundation, the workability of building foundation work is improved, and at the same time, a robust foundation is constructed and the earthquake resistance of the building is improved.

In order to achieve the object, the method for extracting cement in a pile according to the present invention is to dispose an annular tube surrounding at least an upper outer peripheral surface and a lower outer peripheral surface of a cylindrical tool body made of a cardboard made of cardboard. After the tool body is loaded into a hollow concrete pile, a fluid such as air is pressure-fed to the tube to expand the tube to bring the tube into close contact with the inner peripheral surface of the concrete pile, and in that state, The feature is that the concrete pile is buried in the ground.
Further, the device for extracting cement in piles according to the present invention is an at least upper outer peripheral surface and lower outer peripheral part of a cylindrical tool body made of a paper tube made of cardboard, which is an annular tube that can expand when filled with a fluid such as air. It is characterized in that it is arranged so as to surround the surface.
Further, the present invention is characterized in that, in the above-mentioned pile cement removing tool, a small hole is formed in the paper cylinder for allowing the water in the uncured cement to flow out into the space between the upper and lower tubes.
Further, the present invention is characterized in that, in the above-mentioned device for extracting cement in a pile, a guard member is provided at a lower end edge of the paper tube to expand outward in a funnel shape to protect the tube.

  According to the present invention, by expanding the annular tube, it is possible to prevent the uncured cement from entering the gap between the tool body and the inner peripheral surface of the concrete pile. Prevents the formation of a cement layer with low strength on the inner peripheral surface of the vertical hole when the tool body is lifted up with a tool such as to pull it out of the concrete pile and open a vertical hole for establishing columns at the top of the concrete pile. can do. Therefore, it is possible to perform reliable building foundation work with high earthquake resistance, without requiring laborious work such as peeling off the cement layer.

The perspective view of the tool main body of the cement extraction tool in a pile which concerns on this invention. FIG. 3 is a vertical cross-sectional view of the tool main body of the pile cement removal tool according to the present invention. 1 is a perspective view of a pile cement removal tool according to the present invention. 1 is a cross-sectional view of a device for extracting cement in a pile according to the present invention. FIG. 3 is a vertical cross-sectional view of a concrete pile in which the cement removing tool for pile according to the present invention is loaded. FIG. 3 is a vertical cross-sectional view of a concrete pile in which the cement extracting tool for piles according to the present invention is inserted, which is buried in the ground.

  First, the tool body 1 will be described with reference to FIGS. The tool body 1 includes a paper tube 2 made of cardboard having a thickness of about 3 to 8 mm, and a pair of reinforcing materials 3 and 3 made of steel flat bars having a width of several centimeters and a thickness of several millimeters. The inverted U-shaped engaging pieces 4 and 4 are fixed to the upper ends of the pieces 3 and 3 by welding in advance. The reinforcing members 3 and 3 are fixed to the opposing portions of the inner peripheral surface of the paper tube 2 by a plurality of screws 5a and 5b. Further, 6 is a plastic guard member composed of a tubular mounting portion 6a and an umbrella-shaped portion 6b. By fixing the tubular mounting portion 6a to the inner surface of the lower portion of the paper tube 2 with a screw 5b, the umbrella-shaped The portion 6b is provided so as to expand outward from the lower edge of the paper tube 2 in a funnel shape. In addition, a large number of small holes 7 having a diameter of about 1 to 3 mm are formed in a substantially middle portion of the paper tube 2 in the longitudinal direction.

Then, as shown in FIGS. 3 and 4, annular tubes 8a and 8b are fastened so as to surround the upper outer surface and the lower outer surface of the tool body 1 and are provided on the tubes 8a and 8b. Air-supplying hoses 10a and 10b are connected to the valves 9a and 9b, and the other ends of the hoses 10a and 10b are arranged above the tool body 1 as shown in the drawing. The tubes 8a and 8b can be expanded by filling the inside with a fluid such as air. For example, a hose for discharging water from a fire or a waste tire tube can be used, and an inexpensive waste tire tube must be used. Depending on the case, the manufacturing cost can be reduced. If the inner diameter of the tubes 8a, 8b is smaller than the outer diameter of the paper tube 2, the tubes 8a, 8b are naturally fixed to the outer periphery of the tool body 1 by the elasticity of the tubes. It is also possible to provide a fastening means such as a strap or a hook.
The small hole 7 is formed in the portion between the upper and lower tubes 8a and 8b of the paper tube 2.

  As shown in FIG. 5, the cement removing tool for piles constructed as described above is loaded into a hollow concrete pile 20 horizontally placed at a construction site, and the reinforcing bars 21 are attached to the engaging pieces 4 and 4. It is inserted and both ends of the reinforcing bar are fixed to the upper end metal fitting 20a of the concrete pile 20 by welding or the like. Then, a compressor (not shown) is connected to the hoses 10a and 10b, and compressed air is supplied to the tubes 8a and 8b to expand the hoses 10a and 10b, and the tubes 8a and 8b are connected to the outer circumference of the tool body 1. And the inner peripheral surface of the concrete pile 20.

After inflating the tubes 8a and 8b in this way, the concrete pile 20 is lifted up by a digging heavy machine to make it vertical, and as shown in FIG. The pile 20 is buried. Then, the uncured cement 22 rises in the hollow holes of the concrete pile 20 and fills the inside of the paper tube 2, and the uncured cement 22 overflows from the upper end opening of the paper tube 2 but expands the tube. Since 8a and 8b are in close contact with the outer peripheral surface of the tool body 1 and the inner peripheral surface of the concrete pile 20, the uncured cement 22 does not enter the space 23 between the tubes 8a and 8b. Here, the guard member 6 prevents the uncured cement 22 rising from below with rubble from colliding with the tube 8b and damaging the tube 8b. That is, the guard member 6 protects the tubes 8a, 8b by guiding the uncured cement 22 rising in the hollow holes of the concrete pile 20 into the paper tube 2.
By the formation of the small holes 7, the water in the uncured cement 22 filled in the paper tube 2 passes through the small holes 7 and flows into the void 23, and the void 23 is filled with the water. By doing so, the pressure in the void 23 is maintained. Therefore, it is possible to more reliably prevent the uncured cement 22 from entering the voids 23.

  Then, after the uncured cement 22 is solidified, the reinforcing bar 21 is detached from the concrete pile 20, the hanging hook (not shown) of the excavating heavy machine is hooked on the reinforcing bar 21, and the tool body 1 is lifted. Then, the tool body 1 is suspended from the concrete pile 20 together with the hardened cement in the paper tube 2, the tubes 8a and 8b, and the guard member 6. The presence of the void 23 reduces the frictional resistance during the lifting. As a result, vertical holes for establishing columns are formed in the upper portion of the concrete pile 20.

  By expanding the tubes 8a and 8b in this way, the tubes 8a and 8b are brought into a state of strongly adhering to the outer peripheral surface of the tool body 1 and the inner peripheral surface of the concrete pile 20, so that the uncured cement 22 is adhered to the concrete pile 20. It is possible to prevent adhesion and solidification on the inner peripheral surface. Therefore, it is not necessary to perform a troublesome work such as peeling off the solidified cement layer after the tool body 1 is extracted as in the conventional case, and the cement layer having no strength does not intervene between the concrete pile 20 and the building pillar. The strength of the connection with the building is secured, and a strong foundation can be built, improving the earthquake resistance of the building.

  Since the tubes 8a and 8b are annular and are provided so as to surround the upper outer peripheral surface and the lower outer peripheral surface of the tool body 1, as shown in FIG. By inflating 8b, the tool body 1 can be always positioned at the center of the concrete pile 20 without being offset. Therefore, the work of installing the tool body 1 in the concrete pile 20 is also facilitated.

1 Tool Main Body 2 Paper Tube 3, 3 Reinforcing Material 4, 4 Engaging Piece 6 Guard Member 7 Small Holes 8a, 8b Tube 20 Concrete Pile 22 Unhardened Cement 23 Void

Claims (1)

An annular tube that can expand when filled with a fluid such as air is arranged so as to surround at least the upper and lower outer peripheral surfaces of a cylindrical tool body made of a cardboard cardboard, and is uncured. A device for extracting cement in a pile, characterized in that a small hole is formed in the paper cylinder to allow water in the cement to flow out into a space between the upper and lower tubes .

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