Ground anchor head and forming method of ground anchor head

Abstract

To provide a ground anchor head which can be expected to provide higher anticorrosive effect and from which anticorrosive members can be easily removed, and a forming method of a ground anchor head.SOLUTION: A ground anchor head according to the present invention includes a nut part 3, a threaded part 5 that is screwed into the nut part 3, a tendon 7 that is exposed from the end face opposite the nut part 3 through the inside of the threaded part 5, and a wedge part 8 that is arranged in a gap between the tendon 7 and the end face; the side surfaces of the nut part 3, the side surfaces of the threaded part 5, and the end face of the nut part 3 including the gap between the wedge part 8 and an excessive length portion 7a of the tendon 7 and the excessive length portion 7a of the tendon 7 are covered with silicone elastomers 12, 31, 34.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a ground anchor head and a method of forming a ground anchor head. [Background technology]

[0002] Conventionally, a ground anchor method has been known as a construction method for stabilizing buildings or ground, in which a wire is used to tension and fix the underground and ground plate. The basic structure of a ground anchor is broadly divided into an underground anchor part, a ground support plate, and a ground anchor head that holds a wire called a tendon on the ground. The ground anchor head refers to the part above the ground support plate. Many ground anchor heads are equipped with a protective cap to protect the ground anchor head from falling rocks, wind, rain, and dirt. The tendon includes a part exposed above ground and a part buried underground, but in the following explanation, the part of the tendon exposed above ground may be simply called the tendon.

[0003] The ground anchor head is mainly composed of a nut portion, an anchor head screw portion (hereinafter referred to as the screw portion), an excess length portion of the tendon, a wedge portion, and a protective cap. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2987404 [Patent Document 2] JP 2005-213335 A Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, the material that makes up the ground anchor head is generally metal. Therefore, if the ground anchor head is directly exposed to the elements, the metal part may corrode even if a protective cap is attached. This is because rain penetrates through tiny gaps and water leaks from the ground along the tendon. In view of this situation, a more effective corrosion prevention method is desired.

[0006] As a corrosion prevention method, for example, a waterproof structure for the head of an anchor to be buried in the ground has been proposed, in which a thick collar is provided at the mouth of the outer sheath, a groove is formed in the inner circumference of the collar, a water-swelling rubber waterproof seal material is provided in the groove, and the synthetic resin sheath and the mouth of the outer sheath are sealed with the waterproof seal material (see Patent Document 1). However, this waterproof structure requires a dedicated design, so it cannot be applied to waterproofing and corrosion prevention of existing facilities. Also, inspection is only possible after removing the cap and removing the rust-preventive oil.

[0007] As another example of a corrosion prevention method, for example, a form in which the inside of a cap is filled with fluidized grease has been proposed (see Patent Document 2). However, since a dedicated design is required for filling with grease, it cannot be applied to all shapes of ground anchor heads. In addition, the fluidity of grease is extremely low. For this reason, it is difficult to fill small gaps in the fixing member with grease. For this reason, corrosion in small gaps cannot be prevented, and there are cases in which sufficient corrosion prevention effects are not achieved overall.

[0008] An object of the present invention is to provide a ground anchor head which can be expected to have a higher anticorrosive effect and from which the anticorrosive member can be easily removed, and a method of forming a ground anchor head. [Means for solving the problem]

[0009] (1) In order to achieve the above object, a ground anchor head according to one embodiment comprises: a nut portion, a threaded portion that screws into the nut portion, a tendon that is exposed from an end face opposite the nut portion through the inside of the threaded portion, and a wedge portion that is disposed in a gap between the tendon and the end face; The side of the nut portion, the side of the threaded portion, and the end face of the nut portion including the gap between the wedge portion and the excess length of the tendon, and the excess length of the tendon are covered with silicone elastomer. (2) In order to achieve the above object, a ground anchor head according to one embodiment includes a nut portion, a threaded portion that screws into the nut portion, a tendon that passes through the inside of the threaded portion and is exposed from an end face opposite the nut portion, and a wedge portion that is disposed in a gap between the tendon and the end face, The end face of the nut portion, including the side of the nut portion, the side of the threaded portion, and the gap between the wedge portion and the excess portion of the tendon, are covered with silicone elastomer, the excess portion of the tendon is inserted into a silicone rubber tube, and the opening of the tube is sealed with silicone elastomer. (3) In a ground anchor head according to another embodiment, it is preferable that the silicone rubber tube has a hardness of 40 or more and 80 or less when measured based on Durometer Type A (Shore A) in accordance with JIS K 6253, and a total light transmittance of 60% or more when measured based on JIS K 7375. (4) In the ground anchor head according to another embodiment, the silicone elastomer preferably has a total light transmittance of 60% or more when measured according to JIS K 7375. (5) In another embodiment of the ground anchor head, the silicone elastomer has an adhesion strength of 2N / mm in an adhesion test to a hot-rolled steel plate (JIS K 6849) based on JIS K 6849. 2 It is preferable that the adhesive strength is as follows: (6) In the ground anchor head according to another embodiment, it is preferable that at least a portion of the ground anchor head is made of transparent glass or a transparent resin body and is covered with a protective cap that allows the inside to be visually observed. (7) To achieve the above object, a method for forming a ground anchor head according to one embodiment includes the steps of filling an end face of the nut portion, including a gap between the wedge portion and the excess length of the tendon, and the excess length of the tendon with a curable silicone putty in an uncured state of the silicone elastomer, and covering a side surface of the nut portion and a side surface of the threaded portion with the curable silicone putty. (8) To achieve the above object, a method for forming a ground anchor head according to one embodiment includes the steps of filling an end face of the nut portion, including a gap between the wedge portion and the excess length of the tendon, with curable silicone putty in an uncured state of the silicone elastomer, inserting a silicone rubber tube into the excess length of the tendon and sealing an opening of the tube with the curable silicone putty, and covering a side surface of the nut portion and a side surface of the threaded portion with the curable silicone putty. (9) In the method for forming a ground anchor head according to another embodiment, the curable silicone putty may preferably have a plasticity of 100 or more and 600 or less when the plasticity before curing is measured based on ISO 7323. Effect of the Invention

[0010] According to the present invention, it is possible to provide a ground anchor head and a method of forming a ground anchor head which can be expected to have a higher anticorrosive effect and in which the anticorrosive member can be easily removed. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a side view of the ground anchor head according to the embodiment. [Diagram 2] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Diagram 3] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Figure 4] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Diagram 5]2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Figure 6] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Figure 7] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Figure 8] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Figure 9] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Figure 10] 2A to 2C are diagrams for explaining a method of forming the ground anchor head shown in FIG. [Figure 11] FIG. 2 is a diagram showing the completed ground anchor head portion. [Figure 12] A diagram showing the completed ground anchor head. [Figure 13] 13A and 13B are diagrams showing modified examples of the ground anchor head. [Figure 14] FIG. 12 is a view for explaining the anticorrosive removal work for the completed ground anchor head part shown in FIG. 11. [Figure 15] FIG. 12 is a view for explaining the anticorrosive removal work for the completed ground anchor head part shown in FIG. 11. [Figure 16] FIG. 12 is a view for explaining the anticorrosive removal work for the completed ground anchor head part shown in FIG. 11. [Figure 17] FIG. 12 is a view for explaining the anticorrosive removal work for the completed ground anchor head part shown in FIG. 11. [Figure 18] FIG. 12 is a view for explaining the anticorrosive removal work for the completed ground anchor head part shown in FIG. 11. [Figure 19] FIG. 12 is a view for explaining the anticorrosive removal work for the completed ground anchor head part shown in FIG. 11. [Figure 20]FIG. 12 is a view showing the ground anchor head part after the anticorrosive removal work has been completed for the completed ground anchor head part shown in FIG. 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below does not limit the invention according to each claim of the claims. In addition, not all of the elements and combinations described in the embodiment are necessarily essential to the solution of the present invention. For example, although the present embodiment describes a state in which a protective cap is placed, which will be described later, a state without a protective cap may also be used.

[0013] 1, the ground anchor head 1 according to this embodiment comprises a ground anchor head portion 2 and a protective cap 14 for covering the ground anchor head portion 2. The ground anchor head portion 2 comprises a hollow nut portion 3, a threaded portion 5 having a male thread formed on its outer periphery, a tendon group 6, a wedge portion 8, a silicone rubber tube (silicone tube) 10, a silicone elastomer 12, and sheet-shaped silicone elastomers 31, 34.

[0014] Between the nut part 3 and the ground, a bearing plate 16, which is a pressure-receiving structure, is disposed. Between the nut part 3 and the bearing plate 16, a flange 15 having a through hole (not shown) and a recessed portion 15a, into which the nut part 3 is fitted, is interposed. The nut part 3 is a hollow donut-shaped member. A female thread is formed on the inner periphery of the member, which is screwed into the male thread of the threaded part 5. The nut part 3 is fitted into the threaded part 5 by screwing the male thread and the female thread. The axial position of the nut part 3 can be adjusted by rotating the nut part 3. This allows the tensile force of the tendon group 6 to be adjusted. Note that in FIG. 1, the male thread formed on the outer periphery of the threaded part 5 is omitted. The tendon group 6 is also composed of a plurality of tendons 7. In this embodiment, the number of tendons 7 is described as four, but the number is not limited to this.

[0015] The screw portion 5 has four tendon through holes (not shown). A wedge portion 8 is disposed at a position corresponding to each tendon through hole. The wedge portion 8 has a recess 8a having a shape that fits the outer circumference of the tendon 7. The recess 8a is placed on the outer circumference of the tendon 7, so that the tendon 7 is clamped by the recess 8a. The wedge portion 8 is fitted into a wedge socket (not shown) of the screw portion 5, so that the tendon 7 is in a tensioned state. The wedge portion 8 has an effect of preventing the force of the tendon 7 returning to the support plate 16 side due to vibration or the like. The function of the wedge portion 8 is a well-known function, so a detailed description is omitted here. Each tendon 7 is inserted into the corresponding tendon through hole of the screw portion 5 via the corresponding wedge portion 8, and extends into the ground below the support plate 16 through the hollow of the nut portion 3, the flange 15, and the through hole formed in the support plate 16.

[0016] The flange 15 can be screwed to the support plate 16. A seal ring (not shown) is arranged on the underside of the flange 15 to ensure close contact with the support plate 16 while maintaining a watertight state. The flange 15 and the support plate 16 are formed with a plurality of through holes (not shown) through which a plurality of tendons 7 can be inserted, but they may also be hollow to allow a plurality of tendons 7 to be inserted.

[0017] The excess length 7a of the tendon 7 exposed above the upper end surface of the wedge portion 8 is covered with a silicone tube 10 having a transmittance that allows at least the inside to be seen. The axial length of the silicone tube 10 is approximately the same as the axial length of the excess length 7a. A sheet-shaped silicone elastomer 34 having a transmittance that allows at least the inside to be seen is formed (attached) so as to cover the entire side surface of the nut portion 3. In addition, a sheet-shaped silicone elastomer 31 having a transmittance that allows at least the inside to be seen is formed (attached) so as to cover the entire side surface of the threaded portion 5. Furthermore, a silicone elastomer 12 having a transmittance that allows at least the inside to be seen is formed so as to cover the outer periphery of the silicone tube 10, the opening of the silicone tube 10, the end surface of the threaded portion 5, the gap between the wedge portion 8 and the excess length 7a, and the gap between the wedge portions 8 and 8.

[0018] In this way, the entire periphery of the components (except for the protective cap 14) constituting the ground anchor head 1 is covered without any gaps with the sheet-shaped silicone elastomer 31, 34 and the silicone elastomer 12, so that the anticorrosive effect can be increased. The method of forming the silicone tube 10, the silicone elastomer 12 and the sheet-shaped silicone elastomer 31, 34, and the materials therefor will be described later.

[0019] The protective cap 14 is preferably made of transparent glass or transparent resin so that the inside can be seen.

[0020] (Modification) In the above example, the silicone elastomer 12 is formed to cover the outer periphery of the silicone tube 10, the opening of the silicone tube 10, the end face of the threaded portion 5, the gap between the wedge portion 8 and the extra length portion 7a, and the gap between the wedge portions 8 and the wedge portions 8. However, the silicone elastomer 12 may be formed to cover each tendon 7, the end face of the threaded portion 5, the gap between the wedge portion 8 and the extra length portion 7a, and the gap between the wedge portions 8 and the wedge portions 8 without covering each tendon 7 with the silicone tube 10 (see FIG. 13). According to this modification, the silicone elastomer 12 is formed without covering the extra length portion 7a of the tendon 7 with the silicone tube 10, which has the advantage of reducing the number of parts.

[0021] [Silicone elastomer and sheet-like silicone elastomer] The silicone elastomer 12 and the sheet-like silicone elastomers 31 and 34 are silicone elastomers formed by curing a curable silicone putty, which is a curable silicone rubber composition. The curable silicone putty contains, as a main material, an organopolysiloxane polymer represented by the following formula (I). Note that formula (I) is also referred to as chemical formula (I). The same applies to the following formulas (II) and (III).

[0022] [ka] (R in formula (I) 1 is a hydrocarbon group having 1 to 10 carbon atoms. In formula (I), n is, for example, 1.98 to 2.02.

[0023] R in formula (I) 1is a hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms. Examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, an alkenyl group, and an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the cycloalkyl group include a cyclohexyl group. Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, and a hexenyl group. Examples of the aryl group include a phenyl group and a tolyl group. In addition, R 1 The n in the formula (I) may be a group in which some or all of the hydrogen atoms of the hydrocarbon group have been substituted with halogen atoms, cyano groups, etc. In the formula (I), n is 1.98 to 2.02.

[0024] The kinetic viscosity of the organopolysiloxane at 25° C. is preferably 100 to 100,000,000 cSt, and more preferably 100,000 to 10,000,000 cSt. When the kinetic viscosity of the organopolysiloxane at 25° C. is within the above range, the organopolysiloxane has excellent handleability.

[0025] Fillers are not essential ingredients for curable silicone putty, but can be suitably used for the purpose of reinforcing silicone elastomers. Examples of fillers include reinforcing agents (fumed silica, precipitated silica, silica whose surface is hydrophobized with an organic silicon compound, quartz powder, talc, zeolite, bentonite, etc.), fibrous fillers (asbestos, glass fiber, organic fiber, etc.), basic fillers (calcium carbonate, zinc carbonate, zinc oxide, magnesium oxide, celite, etc.), and thickeners (MQ resin, rosin derivatives, etc.). Among these, silica, calcium carbonate, and zeolite are preferably used, and fumed silica and calcium carbonate whose surface is hydrophobized are more preferably used. The amount of the fillers to be added can be selected depending on the purpose and the type of filler, but is within the range of 1 to 90% by volume, and preferably within the range of 5 to 60% by volume, based on 100% by volume of the curable silicone putty.

[0026] The constituent materials of the curable silicone putty may contain, in addition to the main material and filler, a plasticizer, a heat-resistant agent, and the like.

[0027] The plasticity of the curable silicone putty is preferably 100 or more and 600 or less when measured according to ISO 7323. The total light transmittance of the silicone elastomers 12, 31, and 34 after the curable silicone putty is cured is preferably 60% or more when measured according to JIS K 7375. The adhesive strength of the silicone elastomers 12, 31, and 34 to a steel plate (particularly a hot-rolled steel plate) is preferably 2 N / mm when measured according to JIS K 6849. 2 The following is the result.

[0028] The curable silicone putty is also a curable silicone adhesive. The curable silicone adhesive preferably has a Williams plasticity at 25°C in the range of 50 to 500. The Williams plasticity is measured using a parallel plate plasticity meter (Williams plasticometer) in accordance with the measurement method specified in JIS K6249 "Testing method for uncured and cured silicone rubber". The curable silicone adhesive is a condensation reaction type curable silicone rubber composition, and can be cured by a simple means, preferably by leaving it at room temperature to react with moisture in the air. The silicone elastomer (i.e., silicone elastomers 12, 31, and 34) obtained by curing the curable silicone adhesive is preferably a moisture-cured silicone elastomer. The curable silicone adhesive may be an addition reaction type curable silicone rubber composition that is cured by heating. In that case, the curable silicone adhesive is made of a heat-cured silicone elastomer. The condensation reaction type curable silicone rubber composition and the addition reaction type curable silicone rubber composition will be described in detail below.

[0029] (1) Condensation reaction type curable silicone rubber composition When the curable silicone putty is a condensation reaction type curable silicone rubber composition, the condensation reaction type curable silicone rubber composition can be composed mainly of the following components, for example.

[0030] (1-1) Organopolysiloxane The organopolysiloxane is a main component of a condensation reaction type curable silicone rubber composition, and is preferably a diorganopolysiloxane represented by the following chemical formula (II) or chemical formula (III). The chemical formula may be referred to as an average composition formula.

[0031] [ka]

[0032] [ka]

[0033] In the above chemical formulas (II) and (III), R is a monovalent hydrocarbon group. Examples of R include one or more hydrocarbon groups selected from alkyl groups (methyl, ethyl, propyl, butyl, 2-ethylbutyl, octyl, etc.), cycloalkyl groups (cyclohexyl, cyclopentyl, etc.), alkenyl groups (vinyl, propenyl, butenyl, heptenyl, hexenyl, allyl, etc.), aryl groups (phenyl, tolyl, xylyl, naphthyl, diphenyl, etc.), aralkyl groups (benzyl, phenylethyl, etc.), and the above hydrocarbon groups in which at least a part of the hydrogen atoms bonded to the carbon atoms is replaced with a halogen, a cyano group, etc. (chloromethyl, trifluoropropyl, 2-cyanoethyl, 3-cyanopropyl, etc.). The number of carbon atoms in R is preferably 1 to 12, more preferably 1 to 10. In the above chemical formulas (II) and (III), A is an oxygen atom or a polymethylene group (including a methylene group) represented by -(CH2)m- (m is 1 to 8). A is preferably an oxygen atom or an ethylene group.

[0034] In the above chemical formulas (II) and (III), n is the kinematic viscosity of component (1-1) at 25°C of 100 to 1,000,000 cm 2 The kinematic viscosity is an arbitrary number within the range of 500 to 500,000 cm / s. 2 It is more preferable that the range is 1 / s.

[0035] In the above chemical formulas (II) and (III), B is a hydrolyzable group. Examples of B include alkoxy groups (methoxy, ethoxy, propoxy, butoxy, etc.), ketoxime groups (dimethylketoxime, methylethylketoxime, etc.), acyloxy groups (acetoxy, etc.), and alkenyloxy groups (isopropenyloxy, isobutenyloxy, etc.). In the above chemical formulas (II) and (III), x is 2 or 3.

[0036] The above component (1-1) can be produced by known methods (for example, a method based on an equilibrium reaction using a cyclic siloxane or a linear oligomer with an acid catalyst or a base catalyst).

[0037] In addition, when introducing a branched structure into the diorganopolysiloxane, which is the component (1-1), the usual method is to add SiO 3 / 2 Units and SiO 4 / 2 A method can be used in which a silane or siloxane containing at least one of the units is added to an extent that the diorganopolysiloxane does not gel. In order to reduce contamination, it is preferable to remove low molecular weight siloxanes by washing or the like before use of component (1-1).

[0038] (1-2) Crosslinking agent As the crosslinking agent, a silane having two or more, preferably three or more, hydrolyzable groups in one molecule, or a partial hydrolysis condensate of the silane is used. Examples of the hydrolyzable group include an alkoxy group (methoxy group, ethoxy group, butoxy group, etc.), a ketoxime group (dimethylketoxime group, methylethylketoxime group, etc.), an acyloxy group (acetoxy group, etc.), an alkenyloxy group (isopropenyloxy group, isobutenyloxy group, etc.), an amino group (N-butylamino group, N,N-diethylamino group, etc.), and an amide group (N-methylacetamide group, etc.). Among these, it is preferable to use an alkoxy group, a ketoxime group, an acyloxy group, or an alkenyloxy group. The amount of the crosslinking agent to be blended is preferably within the range of 1 to 50 parts by mass, more preferably within the range of 2 to 30 parts by mass, and even more preferably within the range of 5 to 20 parts by mass, relative to 100 parts by mass of the (1-1) component.

[0039] (1-3) Curing catalyst Although the curing catalyst is not essential, the use of the curing catalyst can promote the curing of the curable silicone rubber composition. Examples of the curing catalyst include alkyl tin ester compounds (dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctoate, etc.), titanate ester or titanium chelate compounds (tetraisopropoxytitanium, tetra n-butoxytitanium, tetrakis(2-ethylhexoxy)titanium, dipropoxybis(acetylacetonate)titanium, titanium isopropoxyoctylene glycol, etc.), other suitable organometallic compounds (zinc naphthenate, zinc stearate, zinc-2-ethyloctoate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2-ethylhexoate, cobalt naphthenate, alkoxyaluminum compounds, etc.), aminoalkyl group-substituted alkoxysilanes (3-aminopropionyl silanes, etc.), and the like. Examples of the silanes or siloxanes having a guanidyl group include butyltriethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, etc.), amine compounds or salts thereof (hexylamine, dodecylamine phosphate, etc.), quaternary ammonium salts (benzyltriethylammonium acetate, etc.), lower fatty acid salts of alkali metals (potassium acetate, sodium acetate, lithium oxalate, etc.), lower fatty acid salts of alkali metals, dialkylhydroxylamines (dimethylhydroxylamine, diethylhydroxylamine, etc.), and silanes or siloxanes having a guanidyl group (tetramethylguanidylpropyltrimethoxysilane, tetramethylguanidylpropylmethyldimethoxysilane, tetramethylguanidylpropyltris(trimethylsiloxy)silane, etc.). These may be used alone or as a mixture of two or more. The amount of the curing catalyst added is preferably within the range of 0 to 20 parts by mass, more preferably within the range of 0.001 to 10 parts by mass, and even more preferably within the range of 0.01 to 5 parts by mass, per 100 parts by mass of the component (1-1).

[0040] (1-4) Filler Fillers are not essential, but can be suitably used for the purpose of reinforcement, etc. Examples of fillers include reinforcing agents (fumed silica, precipitated silica, silica whose surface is hydrophobized with an organic silicon compound, quartz powder, talc, zeolite, bentonite, etc.), fibrous fillers (asbestos, glass fiber, organic fiber, etc.), and basic fillers (calcium carbonate, zinc carbonate, zinc oxide, magnesium oxide, celite, etc.). Among these, silica, calcium carbonate, and zeolite are preferably used, and fumed silica and calcium carbonate whose surface is hydrophobized are more preferably used. The amount of the filler to be blended can be selected depending on the purpose and the type of filler, but is within the range of 1 to 90% by volume, and preferably within the range of 5 to 60% by volume, relative to the (1-1) component.

[0041] (1-5) Adhesive properties imparting component The adhesion-imparting component is not essential but is preferably used. Examples of the adhesion-imparting component include amino group-containing organoalkoxysilanes (γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, etc.), epoxy group-containing organoalkoxysilanes (γ-glycidoxypropyltrimethoxysilane, etc.), mercapto-containing organoalkoxysilanes (γ-mercaptopropyltrimethoxysilane, etc.), and reaction mixtures of amino group-containing organoalkoxysilanes and epoxy group-containing organoalkoxysilanes. The amount of the adhesion-imparting component is preferably within the range of 0.1 to 5 parts by mass per 100 parts by mass of the (1-1) component.

[0042] (2) Addition-curing type curable silicone rubber composition When the curable silicone putty is an addition-curing type curable silicone rubber composition, the addition-curing type curable silicone rubber composition can be composed mainly of the following components, for example.

[0043] (2-1) Organopolysiloxane Organopolysiloxane is the main component of the addition-curing type curable silicone rubber composition, and has an average of two or more alkenyl groups in one molecule. Examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, hexenyl, and heptenyl groups. Of these, it is preferable to use vinyl groups. Examples of organic groups bonded to silicon atoms other than alkenyl groups in this component include alkyl groups (methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.), aryl groups (phenyl, tolyl, xylyl, etc.), and halogenated alkyl groups (3-chloropropyl, 3,3,3-trifluoropropyl, etc.). Of these, it is preferable to use methyl groups. Examples of the molecular structure of this component include linear, partially branched linear, branched, network, and dendritic. The viscosity of this component at 25°C is preferably at least 100,000 mPa·s, and more preferably at least 1,000,000 mPa·s.

[0044] Examples of organopolysiloxanes of this component include polydimethylsiloxanes terminated with dimethylvinylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylvinylsiloxane copolymers terminated with dimethylvinylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylvinylsiloxane copolymers terminated with trimethylsiloxy groups at both molecular chain ends, (CH3)3SiO 1 / 2 and (CH3)2(CH2=CH)SiO 1 / 2 The siloxane unit represented by and SiO 4 / 2 and organopolysiloxanes in which at least a portion of the methyl groups of these organopolysiloxanes have been substituted with substituents selected from alkyl groups (ethyl groups, propyl groups, etc.), aryl groups (phenyl groups, tolyl groups, etc.) and halogenated alkyl groups (3,3,3-trifluoropropyl groups, etc.); organopolysiloxanes in which at least a portion of the vinyl groups of these organopolysiloxanes have been substituted with alkenyl groups (allyl groups, propenyl groups, etc.); and mixtures of two or more of these organopolysiloxanes can be used.

[0045] (2-2) Hydrogenated organopolysiloxane Hydrogenated organopolysiloxanes act as curing agents for addition-curable silicone rubber compositions, and have an average of two or more silicon-bonded hydrogen atoms per molecule. Examples of organic groups bonded to silicon in this component include alkyl groups (methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.), aryl groups (phenyl, tolyl, xylyl, etc.), and halogenated alkyl groups (3-chloropropyl, 3,3,3-trifluoropropyl, etc.). Of the above, it is preferable to use methyl groups. Examples of the molecular structure of this component include linear, partially branched linear, branched, network, and dendritic. There are no limitations on the viscosity of this component at 25°C, but it is preferably in the range of 1 to 1,000,000 mPa·s, and more preferably in the range of 1 to 10,000 mPa·s.

[0046] Examples of the hydrogenated organopolysiloxane of this component include polydimethylsiloxane terminated with dimethylhydrogensiloxy groups at both molecular chain ends, polymethylhydrogensiloxane terminated with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylhydrogensiloxane copolymer terminated with trimethylsiloxy groups at both molecular chain ends, cyclic polymethylhydrogensiloxane, (CH3)2HSiO 1 / 2 The siloxane unit represented by and SiO 4 / 2 Organopolysiloxanes having siloxane units represented by the formula (I) and (II), organopolysiloxanes in which at least a portion of the methyl groups of these organopolysiloxanes have been substituted with alkyl groups (ethyl groups, propyl groups, etc.), aryl groups (phenyl groups, tolyl groups, etc.), or halogenated alkyl groups (3,3,3-trifluoropropyl groups, etc.), and mixtures of two or more of these organopolysiloxanes can be used. Among these, it is preferable to use a mixture of an organopolysiloxane having silicon-bonded hydrogen atoms only at both ends of the molecular chain and an organopolysiloxane having silicon-bonded hydrogen atoms in the molecular chain side chains, because this improves the mechanical properties (elongation in particular) of the cured product obtained.

[0047] The content of this component in the addition-curable curable silicone rubber composition is an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component to the alkenyl groups in component (2-1) is in the range of 0.01 to 20, preferably in the range of 0.1 to 10, and more preferably in the range of 0.1 to 5. The reason for specifying the above range is that when the content of this component is at or above the lower limit of the above range, the adhesive silicone rubber tends to be sufficiently cured easily, whereas when it is below the upper limit of the above range, the mechanical properties of the cured adhesive sheet tend to be improved. Furthermore, when a mixture of an organopolysiloxane having silicon-bonded hydrogen atoms only at both molecular terminals and an organopolysiloxane having silicon bonds in side chains on the molecular chain is used as component (2-1), the content of the former organopolysiloxane is preferably an amount such that the molar ratio of silicon-bonded hydrogen atoms in component (2-1) to alkenyl groups is in the range of 0.01 to 10, more preferably 0.1 to 10, and even more preferably 0.1 to 5. Furthermore, the content of the latter organopolysiloxane is preferably an amount such that the molar ratio of silicon-bonded hydrogen atoms in component (2-1) to alkenyl groups is in the range of 0.5 to 20, more preferably 0.5 to 10, and even more preferably 0.5 to 5.

[0048] (2-3) Curing catalyst A curing catalyst is not essential, but a preferred example is a platinum catalyst for hydrosilylation reaction. Examples of platinum catalysts for hydrosilylation reaction include platinum fine powder, platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of platinum and diketones, complexes of chloroplatinic acid and olefins, complexes of chloroplatinic acid and alkenylsiloxanes, and catalysts supported on a carrier (alumina, silica, carbon black, etc.). Among these, it is preferable to use a complex of chloroplatinic acid and alkenylsiloxane because of its high catalytic activity. It is more preferable to use a complex of chloroplatinic acid and divinyltetramethyldisiloxane. The amount of this component is preferably 1 to 1,000 parts by mass, more preferably 1 to 100 parts by mass, in terms of platinum metal atoms, per 1 million parts by mass of component (2-1).

[0049] (2-4) Filler The filler is preferably added to improve the mechanical strength of the addition-curing type curable silicone rubber composition, and a known compound that is usually used in compounding silicone rubber can be used. Examples of this component include fumed silica, precipitated silica, calcined silica, crushed quartz, and powders of these silica powders that have been surface-treated with an organosilicon compound (organoalkoxysilane, organohalosilane, organosilazane, etc.). In particular, to sufficiently improve the mechanical strength of the cured adhesive sheet, it is preferable to use a filler having a BET specific surface area of ​​50 m as this component. 2 It is preferable to use a silica powder having a silica content of 1 / g or more.

[0050] In addition curable silicone rubber compositions of the addition curing type, the addition of this component is optional, but in order to improve the mechanical strength of the cured adhesive silicone rubber, the amount of this component is preferably in the range of 1 to 1000 parts by mass, more preferably in the range of 1 to 400 parts by mass, relative to 100 parts by mass of component (2-1). In addition, the addition curing silicone rubber composition may contain other optional components such as inorganic fillers and organic fillers, such as fumed titanium oxide, diatomaceous earth, iron oxide, aluminum oxide, aluminosilicate, calcium carbonate, zinc oxide, and aluminum hydroxide. The addition curing silicone rubber composition may contain fillers whose surfaces have been treated with the above-mentioned organosilicon compound. The amount of filler to be added can be selected depending on the purpose and the type of filler, but is preferably in the range of 1 to 90% by volume, and more preferably in the range of 5 to 60% by volume, relative to component (2-1).

[0051] (2-5) Adhesive properties imparting component This component is not essential, but can be suitably used to impart and improve the adhesiveness of an addition-curing type curable silicone rubber composition so that it can function as an adhesive. Examples of this component include silane coupling agents and partial hydrolysates thereof (methyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(trimethoxysilyl)propane, bis(trimethoxysilyl)hexane, etc.), organic compounds having "epoxy groups, acid anhydride groups, α-cyanoacrylic groups", siloxane compounds having "epoxy groups, acid anhydride groups, α-cyanoacrylic groups", organic compounds or siloxane compounds having both "epoxy groups, acid anhydride groups, α-cyanoacrylic groups" and alkoxysilyl groups, titanium Examples of the siloxane compounds include tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra(2-ethylhexyl) titanate, titanium ethyl acetonate, titanium acetyl acetonate, etc., aluminum compounds (ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum tris(acetyl acetonate), aluminum monoacetyl acetonate bis(ethyl acetoacetate), etc.), and zirconium compounds (zirconium acetyl acetonate, zirconium butoxy acetyl acetonate, zirconium bisacetyl acetonate, zirconium ethyl acetoacetate, etc.). As the siloxane compounds, those having lower aliphatic unsaturated groups such as alkenyl groups, acryloyl groups, and methacryloyl groups, or those having both of these and hydrosilyl groups, can be expected to effectively contribute to improving adhesion. The content of the adhesion-imparting component is not particularly limited, but is preferably within the range of 0.01 to 10 parts by mass per 100 parts by mass of the component (2-1).

[0052] Furthermore, in order to adjust the curing property of the addition curing type curable silicone rubber composition, acetylene compounds (3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-phenyl-1-butyn-3-ol, etc.), ene-yne ​​compounds (3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne, etc.), organosiloxane compounds having 5 mass% or more of vinyl groups in one molecule (1,3,5,7-tetramethylphenyl) and the like may be added. It is preferable that the composition contains, for example, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, methylvinylsiloxane capped with silanol groups at both molecular chain ends, methylvinylsiloxane-dimethylsiloxane copolymer capped with silanol groups at both molecular chain ends, etc., and other cure inhibitors (triazoles such as benzotriazole, phosphines, mercaptans, hydrazines, etc.). The content of these is not limited, but is preferably within the range of 0.001 to 5 parts by mass per 100 parts by mass of component (2-1).

[0053] The method for preparing the addition curing type curable silicone rubber composition is not limited, and it can be prepared by mixing other optional components as necessary, but it is preferable to add the remaining components to a base compound prepared in advance by heating and mixing the (2-1) and (2-3) components. When other optional components are added, they may be added when preparing the base compound, or when the other optional components are altered by heating and mixing, they may be added when adding the (2-2) and (2-4) components. When preparing the base compound, the above-mentioned organosilicon compound may be added to in-situ treat the surface of the (2-3) component.

[0054] [Silicone rubber tube] The silicone rubber tube is a tube made of cured silicone rubber. The curable silicone composition for producing the tube-shaped silicone rubber may contain the main material shown in the above formula (I) and the components required for curing, as well as the above-mentioned filler, plasticizer, heat resistance agent, etc. Here, the components required for curing can include, for example, a crosslinking agent and a curing catalyst. When the curable silicone composition is a photocurable composition, a photoinitiator can be included as a component required for curing.

[0055] The silicone rubber preferably has a hardness of 40 or more and 80 or less, as measured by durometer type A (Shore A) according to JIS K 6253. The silicone rubber preferably has a total light transmittance of 60% or more, as measured by JIS K 7375. It is preferable that the silicone rubber has both a hardness and a total light transmittance in the above ranges, but the silicone rubber may have only a hardness or only a total light transmittance in the above range.

[0056] [How to form a ground anchor head] A method for forming the ground anchor head 1 will be described in detail below with reference to FIGS. The method for forming the ground anchor head according to one embodiment includes the steps of filling the end face of the nut part 3, including the gap between the wedge part 8 and the excess part 7a of the tendon 7, with a curable silicone putty 12a, inserting a silicone rubber tube (also called a silicone tube) 10 into the excess part 7a of the tendon 7 and sealing the opening of the tube 10 with the curable silicone putty 12a, and covering the side surface of the nut part 3 and the side surface of the threaded part 5 with the curable silicone putty 31a, 34a. The formation method will be described in more detail below. (1) As shown in FIG. 2, a clay-like hardening silicone putty 12a is molded to cover the periphery of the four wedge portions 8. (2) The tendon 7 is inserted into the through hole 21 of a bowl-shaped jig 20 having a through hole 21 formed at a position corresponding to the tendon 7, and pressure is applied vertically downward to push it in (see Figure 3: the curable silicone putty 12a is omitted in Figure 3), forming the curable silicone putty 12a covering the periphery of the wedge portion 8 into a disk shape (see Figure 4). (3) After that, the jig is removed, and the four exposed excess lengths 7a are covered with silicone tubes 10 (see FIG. 5), and the silicone tubes 10 are further pushed downward to bury the bottoms of the silicone tubes 10 in the curable silicone putty 12a (see FIG. 6). (4) The opening 24 of the silicone tube 10 is sealed with a curable silicone putty 12a (see FIG. 7). (5) A sheet-like member 30 consisting of a sheet-like curable silicone putty 31a and a peelable release film 32 attached to one side of the sheet-like curable silicone putty 31a is wrapped around the outer periphery of the screw portion 5 and fixed in place (see FIG. 8). (6) A sheet-like member 33 consisting of a sheet-like curable silicone putty 34a and a peelable release film 35 attached to one side of the sheet-like curable silicone putty 34a is wrapped around the outer periphery of the nut portion 3 and fixed in place (see Figure 9). (7) Thereafter, the release films 32, 35 are peeled off (see FIG. 10), and after the peeling, sheet-like curable silicone putties 31a, 34a are formed on the outer peripheral surface of the nut portion 3 (see FIG. 11). Note that, regarding the film peeling operation, the release film 32 may be peeled off after wrapping the sheet-like member 30, and then the sheet-like member 33 may be wrapped around it, and then the release film 35 may be peeled off, or the sheet-like members 30 and 33 may be wrapped around it at the same time, and then the release films 32, 35 may be peeled off at the same time. (8) When the above-mentioned film peeling operation is completed, the construction of the ground anchor head portion 2 is completed (see FIG. 11), the curable silicone putty 12a, 31a, 34a cures to become silicone elastomer 12, 31, 34, and the corrosion prevention process is completed. (9) After that, the protective cap 14 is placed on the ground anchor head portion 2 to complete the ground anchor head 1 (see FIG. 12). Note that the protective cap 14 may be placed on the ground anchor head portion 2 before the curable silicone putties 12a, 31a, and 34a are cured. [Corrosion prevention and removal process] (1) The sheet-like silicone elastomer 34 attached to the outer periphery of the nut portion 3 is peeled off (see FIG. 14). (2) Next, the sheet-like curable silicone elastomer 31 attached to the outer periphery of the threaded portion 5 is peeled off (see FIG. 15). (3) Next, the silicone elastomer 12 in the vicinity of the top of the threaded portion 5 including the wedge portion 8 is peeled off (see FIG. 16). (4) All of the silicone tubes 10 are removed from the corresponding tendons 7 using an elongated removal tool 40 (see FIG. 17). (5) The silicone elastomer 12 remaining in the recessed portion 8a of the wedge portion 8 is removed using a removal tool 40 (see FIG. 19). Note that it is easier to remove the silicone elastomer 12 by inserting the removal tool 40 into the recessed portion 8a and prying it up. (6) When all of the above-mentioned removal steps are completed, the anticorrosion removal work is finished. After the anticorrosion removal work is finished, the ground anchor head part 2a (see FIG. 20) that has not been subjected to anticorrosion treatment is subjected to predetermined maintenance and inspection.

[0057] [Variations] Next, a method for forming a ground anchor head according to a modified example will be described. The method for forming a ground anchor head according to the modified example includes a step of filling the end face of the nut part 3, including the gap between the wedge part 8 and the excess part 7a of the tendon 7, and the excess part 7a of the tendon 7 with a curable silicone putty 12a, and a step of covering the side surface of the nut part 3 and the side surface of the threaded part 5 with the curable silicone putty 12a (or 31a, 34a). As a result, a ground anchor head covered with a silicone elastomer 12 can be formed without using a silicone tube 10 (see FIG. 13). [Explanation of symbols]

[0058] 1 Ground anchor head, 2 Ground anchor head portion, 3 Nut portion, 5 Screw portion, 6, 7 Tendon, 7a Extra length portion, 8 Wedge portion, 10 Silicone tube, 12 Silicone elastomer, 12a Curable silicone putty, 14 Protective cap, 31, 34 Sheet-shaped silicone elastomer, 31a, 34a Curable silicone putty

Claims

1. A ground anchor head comprising a nut portion, a threaded portion that screws into the nut portion, a tendon that is exposed from an end face opposite to the nut portion through the inside of the threaded portion, and a wedge portion that is disposed in a gap between the tendon and the end face, A ground anchor head characterized in that the side of the nut portion, the side of the threaded portion, and the end face of the nut portion including the gap between the wedge portion and the excess portion of the tendon, and the excess portion of the tendon are covered with silicone elastomer.

2. A ground anchor head comprising a nut portion, a threaded portion that screws into the nut portion, a tendon that is exposed from an end face opposite to the nut portion through the inside of the threaded portion, and a wedge portion that is disposed in a gap between the tendon and the end face, A ground anchor head characterized in that the end face of the nut portion, including the side face of the nut portion, the side face of the screw portion, and the gap between the wedge portion and the excess portion of the tendon, are covered with silicone elastomer, the excess portion of the tendon is inserted into a silicone rubber tube, and the opening of the tube is sealed with silicone elastomer.

3. 3. The ground anchor head according to claim 2, characterized in that the silicone rubber tube has a hardness of 40 or more and 80 or less when measured based on durometer type A (Shore A) in accordance with JIS K 6253, and a total light transmittance of 60% or more when measured based on JIS K 7375.

4. 4. The ground anchor head according to claim 1, wherein the silicone elastomer has a total light transmittance of 60% or more in a measurement of the total light transmittance based on JIS K 7375.

5. The silicone elastomer had an adhesion strength of 2 N / mm in a hot-rolled steel plate (JIS K 6849) based on JIS K 6849. ２ A ground anchor head according to any one of claims 1 to 3, characterized in that it has an adhesive strength of:

6. 4. The ground anchor head according to claim 1, characterized in that at least a portion of the ground anchor head is made of transparent glass or a transparent resin body and is covered with a protective cap that allows the inside to be visually observed.

7. 2. A method of forming the ground anchor head of claim 1, comprising the steps of: filling the end face of the nut portion, including the gap between the wedge portion and the excess portion of the tendon, and the excess portion of the tendon with a curable silicone putty in a state before the silicone elastomer is cured; covering a side surface of the nut portion and a side surface of the screw portion with the curable silicone putty; 13. A method for forming a ground anchor head comprising:

8. 3. A method of forming a ground anchor head according to claim 2, comprising the steps of: filling the end surface of the nut portion, including the gap between the wedge portion and the excess portion of the tendon, with a curable silicone putty in a state before the silicone elastomer is cured; a step of inserting a silicone rubber tube into the excess portion of the tendon and sealing an opening of the tube with the curable silicone putty; covering a side surface of the nut portion and a side surface of the screw portion with the curable silicone putty; 13. A method for forming a ground anchor head comprising:

9. 9. The method for forming a ground anchor head according to claim 7 or 8, wherein the curable silicone putty has a plasticity of 100 or more and 600 or less when measured for plasticity before curing according to ISO 7323.

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