Formwork separator and underground formwork construction method using the same

Abstract

This invention provides a formwork separator and an underground formwork construction method using the same, which enable simple installation by allowing the separator to be installed on the retaining wall by nailing it in place, and by fixing the separator in place by nailing it in place, waterproofing between the separator and the retaining wall is immediately completed. [Solution] This is used for concrete formwork for forming a basement. A formwork separator 3 is made of a hollow tube 5 with a flange 4 formed at one end for nailing into a retaining wall 1, and a screw shaft 7 is screwed into the tube 3. A polyurea resin molded plate 9 that extends beyond the outer circumference of the flange 4 is attached to the contact surface of the flange 4 with adhesive.

Description

Technical Field

[0001] The present invention relates to a formwork separator for holding formworks at arbitrary intervals and for use in leak prevention measures for a constructed concrete underground wall, and an underground formwork construction method using the same.

Background Art

[0002] Conventionally, when constructing a concrete underground wall, for example, a separator is attached to a retaining wall, and a sheet-like waterproof material is laid along the wall surface of the retaining wall while being pierced through the separator. A formwork separated from the wall surface of the retaining wall by a predetermined interval is supported by the separator, and concrete is placed between the retaining wall and the formwork.

[0003] However, when placing concrete in the formwork, the sheet-like waterproof material is often pulled downward, and a gap is often generated between the separator and the sheet-like waterproof material, leading to water leakage.

[0004] [[ID=Id=19]] [[ID=Id=Id=20]]In contrast, Patent Document 1 below constitutes a separator device with a mounting fitting fixed to a retaining wall and a separator attached to the retaining wall via the mounting fitting. At the stage where the sheet-like waterproof material is installed while piercing through the shaft portion of this mounting fitting, a tightening nut is screwed onto the shaft portion, and the sheet-like waterproof material is clamped and fixed between the tightening nut and the base end flange portion.

Patent Document 1

[0005] And a rod-shaped separator is attached to the connection portion of the shaft portion, and a formwork is supported on the tip side thereof.

[0006] When the separator device is installed in this way, even if the sheet-like waterproof material is pulled downward when placing concrete in the formwork, the sheet-like waterproof material is clamped and fixed between the tightening nut and the base end flange portion, so it is said that a gap can be prevented from occurring in this portion.

[0007] Patent Document 2 below describes a separator into which a waterproofing material can be injected. When water leakage occurs after the construction of the underground wall, the separator part, which is detachably connected to the cylindrical part, can be removed to supply the waterproofing material to a hole in the concrete that communicates with the inner hole of the cylindrical part, thereby filling the gap between the ground and the underground wall from the tip side of the cylindrical part with the waterproofing material. [Patent Document 2] Japanese Patent Publication No. 2007-277881 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In the method of laying sheet-type waterproofing material along the wall surface of the retaining wall, cracks may occur in the sheet-type waterproofing material when concrete is poured, or the joints between the sheet-type waterproofing materials may peel off over time, causing water leakage from joints and cracks in the underground wall.

[0009] Furthermore, in the method described in Patent Document 2, where a waterproofing material is injected into the separator, it is difficult to reliably fill the gap between the ground and the underground wall from the tip of the separator with the waterproofing material. Moreover, the time and effort required to inject the waterproofing material into each separator is considerable.

[0010] Furthermore, regarding the installation of separators, if they are attached by welding as described in Patent Document 1, the installation locations are limited to the steel sheet piles of the H-shaped steel that constitute the retaining wall.

[0011] The object of the present invention is to eliminate the disadvantages of the conventional example and to provide a formwork separator and an underground formwork construction method using the same that enable simple installation, such as being able to install the separator to the retaining wall by nailing it in place, and immediately completing waterproofing between the separator and the retaining wall by fixing the separator in place with nails. [Means for solving the problem]

[0012] To achieve the above objective, the present invention provides a formwork separator that, firstly, is used in concrete formwork for forming basements, and is a formwork separator in which a screw shaft is screwed into a hollow tube body with a flange formed at one end for nailing into a retaining wall, and a polyurea resin molded plate with an outer circumference that extends beyond the outer circumference is attached with adhesive to the contact surface of the flange; secondly, the polyurea resin molded plate is 2 mm thick; and thirdly, the flange is a 50 mm x 50 mm square, and the polyurea resin molded plate is an 85 mm x 85 mm square.

[0013] The underground formwork construction method using formwork separators involves using a formwork separator in which a polyurea resin molded plate extending beyond the outer circumference is attached with adhesive to the contact surface of the flange. The flange is then nailed to the retaining wall so that the polyurea resin molded plate passes through the nail holes in the flange, and the formwork separator is set between the formwork and the retaining wall. Reinforcement is then placed between the retaining wall and the formwork, and concrete is poured to construct the underground wall.

[0014] According to the present invention as described in claim 1, unlike the method of laying sheet-like waterproofing material, by nailing the flange to the retaining wall and installing the formwork separator, a polyurea resin molded plate can be sandwiched between the flange and the retaining wall. Moreover, the nails that penetrate the flange and are driven into the retaining wall also penetrate the polyurea resin molded plate, and the area around the nails can also be sealed with this polyurea resin molded plate.

[0015] Furthermore, the formwork separator, used as concrete formwork for basement construction, consists of a hollow tube with a flange at one end that is nailed to the retaining wall, and a screw shaft that is threaded onto it. Water could potentially leak out through the flange and the hollow tube, but the polyurea resin molded plate seals the entire flange and completely closes the opening in the hollow tube, thus preventing water from leaking to the outside of the formwork separator.

[0016] According to the present invention described in claim 2, in order for the polyurea resin molded plate to fully exhibit water stoppage, it is necessary for the polyurea resin molded plate to have a predetermined thickness, which can be ensured by setting the thickness to 1 mm or more.

[0017] According to the present invention described in claim 3, the overhang degree of the polyurea resin molded plate with respect to the flange is set to a size that can obtain a sufficient water stoppage effect.

[0018] According to the present invention described in claim 4, as an underground formwork construction method using the formwork separator described in claim 1, water stoppage is completed only by fixing this formwork separator to the retaining wall with the flange.

Effect of the Invention

[0019] As described above, the formwork separator of the present invention and the underground formwork construction method using the same enable a simple installation in which the separator can be installed by fixing it to the retaining wall, and water stoppage between the separator and the retaining wall is immediately completed by fixing the separator.

Brief Description of the Drawings

[0020] [Figure 1] It is a side view showing one embodiment of the formwork separator of the present invention and the underground formwork construction method using the same. [Figure 2] It is a perspective view of a main part showing one embodiment of the formwork separator of the present invention. [Figure 3] It is an explanatory view of a water stop ring used in the formwork separator of the present invention. [Figure 4] It is a perspective view showing the construction situation of an experimental device for confirming the water stoppage effect of the formwork separator of the present invention. [Figure 5] It is a perspective view of the concrete placement of the construction situation of an experimental device for confirming the water stoppage effect of the formwork separator of the present invention. [Figure 6] It is a perspective view of the water injection test of an experimental device for confirming the water stoppage effect of the formwork separator of the present invention. [Figure 7]This is a front view of the wooden hole of an experimental device for confirming the water-stopping effect of the formwork separator of the present invention. [Figure 8] This is a schematic diagram of the experimental process of an experimental device for confirming the water-stopping effect of the formwork separator of the present invention.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing one embodiment of the formwork separator of the present invention and an underground formwork construction method using the same. In the figure, 1 is a retaining wall, 2 is the ground, and 3 is a metal formwork separator made of steel or the like. This formwork separator 3 is used for the concrete formwork of basement formation.

[0022] As shown in FIG. 2, the formwork separator 3 is formed by screwing a screw shaft 7 into a hollow tube 5 having a rectangular flange 4 formed at one end. The hollow tube 5 stands upright from the flange 4 at the center of the flange 4, and the hollow portion of the hollow tube 5 opens and passes through the flange 4.

[0023] Further, the flange 4 is drilled with bolt through-holes 6, three on each side in the illustrated example. As an example, one side of the flange 4 is 50 mm, but it is not particularly limited thereto.

[0024] [[ID=尽23]]Also, the height of the hollow tube 5 is 100 mm in the illustrated example.

[0025] In the figure, 8 is a wooden block, which is called a P-block as a plastic part and is screwed to the end of the screw shaft 7.

[0026] An outer peripheral polyurea resin molding plate 9 that protrudes from the outer periphery is attached to the contact surface of the flange 4 with an adhesive.

[0027] The polyurea in the polyurea resin of the polyurea resin molded sheet 9 has the molecular structure shown in Formula 1 below, and is produced by reacting polyisocyanate and polyamine. Polyurea resin is a resin compound produced by mixing two liquids: Agent A, which mainly consists of isocyanate, and Agent B, which mainly consists of an amine compound.

number

[0028] Polyurea resins, which are compounds primarily composed of urea bonds formed by the chemical reaction between isocyanates and amino groups, have an extremely fast curing time of just a few seconds, are solvent-free and catalyst-free, are environmentally friendly, and exhibit excellent chemical resistance such as acid and alkali resistance, as well as durability. Compared to (poly)urethane, they have stronger bonding strength and do not hydrolyze, resulting in superior water resistance, corrosion resistance, and chemical resistance.

[0029] Furthermore, polyurea resins have excellent mechanical strength. In addition, aliphatic polyurea resins exhibit less yellowing due to UV exposure, which is a drawback of aromatic polyurea resins.

[0030] The difference between polyurea and polyurethane lies in the fact that, although polyurea is also based on the exothermic reaction between MDI and polyisocyanate, the crucial difference is the use of an active hydrogen group called "amine." This reaction with amine allows polyurea to form a stronger and more stable compound compared to conventional polyurethane. In particular, the CN bonds in the polyurea structure are stronger than the CO bonds in the polyurethane structure, resulting in significantly improved heat resistance and impact resistance.

[0031] Polyurea possesses high elasticity and the ability to flexibly follow the movement and cracking of the substrate. This property effectively absorbs stress on buildings and structures, preventing cracks and damage. Conventional polyurethane has weaker conformability and tends to crack easily.

[0032] Conventional polyurethanes are highly sensitive to moisture and humidity, often leading to curing failures and degradation. In particular, under high humidity conditions, the curing process of polyurethane can be inhibited, reducing the strength of the coating. In contrast, polyurea is 100% hydrophobic, and its curing is not inhibited by moisture or humidity. It can even cure on a water surface, and its performance after curing is not compromised.

[0033] Polyurethane, after curing, is prone to degradation when exposed to ultraviolet light, so it generally requires a topcoat. Polyurea, however, is largely unaffected by ultraviolet light and can maintain its coating performance for a long period, significantly reducing maintenance effort.

[0034] Conventional polyurethanes are prone to hydrolysis in environments constantly exposed to moisture, which reduces their durability. In contrast, polyurea is highly resistant to hydrolysis, maintaining its strength and performance even when exposed to moisture. Therefore, it can be used with confidence even in harsh outdoor environments and high-humidity locations.

[0035] The polyurea resin molded sheet 9 is formed by heating a two-component material consisting of a main material and a hardener using a dedicated machine, pumping it through a hose, mixing and stirring it at the end of the hose, and then spraying it onto a flat, concave, or convex mold.

[0036] There are no particular limitations on the adhesive used to attach the polyurea resin molded plate 9 to the flange 4, but modified silicone-based adhesives, or one-component or two-component urethane or urea-based adhesives are suitable. Examples of one-component adhesives include Highflex UH-1 from Daiflex Co., Ltd. and SU Sealant QUIC NB from Toko Sangyo Co., Ltd. Modified silicone-based adhesives are preferable because they do not undergo hydrolysis at all.

[0037] Examples of two-component types include Highflex PU-2 from Daiflex Co., Ltd. and Bond Viewseal 6909 from Konishi Corporation.

[0038] The polyurea resin molded sheet 9 shall have a thickness of 1 mm or more. In the illustrated example, it is 2 mm thick.

[0039] As an example, the flange was a 50mm x 50mm square, and the polyurea resin molded plate 9 was an 85mm x 85mm square.

[0040] In this underground formwork construction method using the formwork separator 3 of the present invention, the flange 4 is nailed to the retaining wall 2 with nails 10 so that the polyurea resin molded plate 9 passes through the nail through holes 6 of the flange 4, and the formwork separator 3 is brought into contact with the formwork (not shown).

[0041] After that, reinforcement bars are placed between retaining wall 2 and the formwork, and concrete is poured to construct the underground wall.

[0042] When setting the formwork separator 3, the water-stopping ring 11 may be attached in the middle of the formwork separator 3. The water-stopping ring 11 is a disc-shaped, thick ring body molded from a water-swellable resin, with a through hole 11a in the center and bulging out around the periphery as ribs 11b.

[0043] An experiment was conducted to confirm the water-stopping effect of the formwork separator 3 of the present invention. 1. Subjects of the experiment Creating a virtual model of a basement using concrete structures. The experimental structure is Concrete wall W1,200×H2,000@2204 sides (A,B,C,D) 2. Challenges The separator holes have weak waterproofing and are at risk of water pressure and ingress. (See Figure 7) The effectiveness of the following waterproofing methods under water pressure was verified. 3. Experimental Process Waterproofing treatment was applied to the separator body and the sheet pile contact surface (assuming it is on the mountain side). A certain amount of water is added, and pressure is applied. A schematic diagram is shown in Figure 8. 4. Evaluation Items Waterproofing performance under water pressure (presence or absence of water leakage). Durability of the processed separator holes. <Injection time> Water filling started at 13:00 and ended at 13:45. External dimensions of container: 1200mm x 1200mm x 2000mm Concrete side thickness: 220mm (applies to each side) Internal dimensions: 760mm x 760mm Effective water depth: 2000mm (2.0 m) Internal volume (water volume): Approx. 1.1552m 3 = about 1155L

[0044] The evaluation results showed no water leakage at all in the areas where the mold separator of the present invention was used, but water leakage was confirmed in the areas where the mold separator was used without the polyurea resin molded plate attached. [Explanation of symbols]

[0045] 1…Mountain retaining wall 2…Underground ground 3…Formwork separator 4…Flange 5…Hollow tube body 6…Nail penetration hole 7...Screw shaft 8...Wooden concrete 9…Polyurea resin molded sheet 10... Nail 11... Water stop ring 11a...Through hole 11b...Rib

Claims

1. A formwork separator for use in concrete formwork for forming basements, characterized in that a screw shaft is screwed into a hollow tube body with a flange formed at one end for nailing into a retaining wall, and a polyurea resin molded plate with an outer circumference that protrudes from the outer circumference is attached with adhesive to the contact surface of the flange.

2. The mold separator according to claim 1, wherein the polyurea resin molded plate has a thickness of 1 mm or more.

3. The mold separator according to claim 2, wherein the flange is a 50 mm x 50 mm square and the polyurea resin molded plate is an 85 mm x 85 mm square.

4. This underground formwork construction method uses a formwork separator, which has a polyurea resin molded plate with an outer circumference that extends beyond the outer circumference attached to the contact surface of the flange with adhesive. The flange is nailed to the retaining wall so that the polyurea resin molded plate passes through the nail holes in the flange, and the formwork separator is set between the formwork and the retaining wall. Reinforcement is placed between the retaining wall and the formwork, and concrete is poured to construct the underground wall.

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