JPH10292799A - Lock bolt construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase integrality with ground and improve durability and workability by inserting a GRP bolt that is a hollow rod member and has bolt-thread form and fixing it to the ground with a resin fixing material. SOLUTION: A glass fiber reinforced plastic lock bolt (GRP bolt) 10 is a rod member with almost a circular cross section with a bolt thread form by providing a thread on the external face of the side wall. The GRP bolt 10 is in a hollow state with both ends opened, and a fixing material injection pipe 30 is connected to the opening in this side through a connecting member 20. The connecting member 20 is of a nut-thread form and is screwed together with the GRP bolt 10. When it is made of aluminum it can be made lightweight, strong and corrosion resistant. The GRP bolt 10 is inserted into an excavated hole 2 in ground 1, and then the fixing material injection pipe 30 is connected through the connecting member 20. When a silica resin is injected from the fixing material injection pipe 30, the silica resin flows out from the head of the GRP bolt 10 and is filled into the excavated hole 2 and the GRP bolt 10 is integrated with the ground 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for stabilizing loose ground with rock bolts.

[0002]

2. Description of the Related Art Conventionally, in a tunnel construction or the like, a rock bolt is inserted into a loose ground to be integrated with the ground,
A construction method that stabilizes the ground by the anchor effect is adopted.

[0003] As a method of integrating the ground and the rock bolt, for example, a capsule containing a resin-based fixing material is first inserted into the hole wall of a hole formed in the ground, and then a metal-made material is formed. Is pressed in, and the capsule is crushed and mixed while applying rotation, and the space between the hole wall and the lock bolt is filled with a cured resin. Alternatively, a method in which a cement-based fixing material such as cement or mortar is filled in a hole wall of a drilled hole provided in advance, and a lock bolt is inserted to integrate with a ground is adopted.

[0004]

However, the conventional lock bolts are made of metal such as steel and are susceptible to corrosion, so that they have poor durability and have a problem in the sustainability of the ground stabilizing effect. . In addition, the weight was large and workability was poor.

In the former method of integrating the ground and the lock bolt, in the former method, when it is difficult to make the hole wall independent, a capsule containing a resin-based fixing material is inserted into the hole. Since the mixing of the fixing material components is performed only by the rotation of the lock bolt, the fixing material tends to be insufficient, and the performance of the fixing material is not sufficiently exhibited.

On the other hand, the latter method using a cement-based fixing material has the disadvantage that it takes a long time to integrate with the ground because the strength of the fixing material is slow to develop. If a hardener is added to accelerate the hardening, the hardening will proceed and the fluidity will be lost before the lock bolt is inserted after the injection into the hole and the lock bolt will not be able to be inserted. There is a problem that a gap is generated between them and the integrity with the ground is lost.

The present invention has been made in view of such problems of the prior art, and provides a lock bolt method which is excellent in integration with the ground and has excellent durability and workability. What you want to do.

[0008]

According to the first aspect of the present invention, a lock bolt made of glass fiber reinforced plastic (hereinafter, referred to as a GRP bolt) is provided in a hole formed in a ground to solve the above-mentioned problem. In a lock bolt method for stabilizing the ground by fixing the lock bolt to the ground using a resin-based fixing material (hereinafter simply referred to as a fixing material), a rod-shaped member having a substantially circular cross section is used. A GRP bolt having an external thread and having a thread on the outer surface of the side wall is used.

In the rock bolt method, it is preferable that the lock bolt is hollow, and the fixing material is injected from the hollow portion.

Therefore, the fixing material injection side end of the lock bolt can be connected to the pipe into which the fixing material is injected via an aluminum female screw connection member.

The lock bolt is extended by connecting the lock bolts via an aluminum female threaded connecting member as required (claim 4).

The fixing material is preferably a silica resin containing an aqueous alkali silicate solution and isocyanate as main components.

Further, the fixing material may be injected into the hole wall of the hole and penetrate into the underground portion.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A GRP bolt used in the present invention is an elongated rod-like member having a substantially circular cross section and made of a material reinforced with a resin such as an epoxy resin or a polyester resin with glass fibers. It is provided and has a male screw shape. The tensile rupture strength of GRP bolts is 5
It is preferably at least t.

The GRP formed in a male screw shape as described above
The bolt has a large contact area with the fixing material as compared with a bolt having a flat surface, and thus has an excellent effect of integration with the ground. In addition, as described later, there is an effect that connection with other members is facilitated. The thread is not necessarily provided in the entire length direction of the GRP bolt, but is preferably provided at least at both ends for connection with other members. In order to make the formation more robust, it is preferable that the coating be provided over a wide range. Therefore,
Most preferably, it is provided entirely.

It is preferable that the GRP bolt is formed in a hollow shape having both ends opened so that the fixing material is injected from the opening on the hand side and flows out into the hole from the opening on the tip side. To do so, open the hand side opening of the GRP bolt,
It is necessary to connect to a tube such as a hose for injecting the fixing material (hereinafter, referred to as a fixing material injection tube). The connecting member used for this purpose preferably has a female screw-shaped portion that can be screwed with the GRP bolt, and is preferably made of aluminum because it is light and high in strength and corrosion resistant. The connection method between the connection member and the fixing material injection pipe is not particularly limited, and a method such as insertion and screwing can be used as appropriate.

The length of the GRP bolt is not particularly limited, but is usually about 3 to 6 m, and can be extended by connecting two or more GRP bolts as needed. In this case, the tensile rupture strength of the connecting portion is 5t.
It is desirable that this is the case.

The shape of the connecting member used for the connection is not particularly limited, but it is preferable that the connecting member has a female screw portion which can be screwed with a male screw GRP bolt from the viewpoint of easy connection. The connecting member is preferably made of aluminum for the same reason as the connecting member.

In order to allow the fixing material to spread more quickly around the bolt, one or a plurality of through holes through which the fixing material flows out may be provided on the side wall of the GRP bolt as necessary. The diameter, number, position, and the like of the through holes may be determined as appropriate according to the viscosity of the fixing material, the state of the ground, and the like.

The resin-based fixing material used in the present invention comprises a synthetic resin as a main component, and the type thereof is not particularly limited. For example, a two-liquid reaction type urethane resin containing a polyol and an isocyanate compound as main components. Further, a silica resin containing an aqueous alkali silicate solution and an isocyanate compound as main components can be given as an example.

Examples of the polyol which is a component of the urethane resin include dihydric alcohols such as 1,3-butanediol, 1,4-butanediol and 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, and the like. Single or mixture of propylene glycol, dipropylene glycol, butylene glycol, acetylene glycol, glycerin, trimethylolpropane, diglycerin, castor oil, dehydrated castor oil, sorbitol, sucrose, etc., and alkylene oxide such as propylene oxide or ethylene oxide added to these Examples include a polymerized polyol. Also, amine polyols obtained by addition polymerization of ethylenediamine, aniline, tolylenediamine, mono-, di- or triethanolamine with an alkylene oxide such as propylene oxide or ethylene oxide are effective. Various polyester polyols obtained by a dehydration condensation reaction of dibasic acids such as adipic acid and phthalic anhydride with glycols such as ethylene glycol, diethylene glycol and trimethylolpropane, and lactones obtained by ring-opening polymerization of ε-caprolactam Polyester polyols, phosgenation of polyols, polycarbonate diols synthesized by transesterification with diphenyl carbonate, other acrylic polyols, polybutadiene-based polyols, Mannich polyols, novolak resins, resol resins, etc. obtained by addition polymerization of propylene oxide or ethylene oxide Phenolic polyols, and those obtained by radical polymerization of vinyl monomers such as acrylonitrile and styrene in the polyol. Polymer polyol obtained by dispersing dissolving these polymers in polyols, polytetramethylene glycol obtained by cationic polymerization of tetrahydrofuran, these modified polyols obtained by addition polymerization of alkylene oxides.

The isocyanate compound may be any as long as it reacts with the polyol to form a polyurethane.
Polymers such as isocyanate monomers, dimers and trimers thereof, and those modified with alcohols and polyols are all effective. The content of the isocyanate group is from 5 to 48% by weight, preferably from 10 to 33%, from the viewpoint of the physical properties of the solidified body.
Preferably, it is weight%.

Specific examples of such isocyanate compounds include polymethylene polyphenyl isocyanate, liquid diphenylmethane diisocyanate, tolylene diisocyanate, crude tolylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate,
Naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, a single or mixture of polyisocyanates such as trimethylene xylylene diisocyanate, and further reacting the polyisocyanate with an adduct or a polyisocyanate modified with water or a lower mono- to polyhydric alcohol and various polyols. Or a mixture of an adduct or a prepolymer thereof with one or more of the above-mentioned various polyisocyanates, and further adding a catalyst to the polyisocyanate. And those in the form of a trimer or trimer.

Among these various isocyanate compounds, liquid diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, urethane prepolymer containing terminal isocyanate group, adduct, and the like are preferable from the viewpoints of solidification strength, safety and hygiene, and economy. It is preferable to use a material which has a very low volatility at ambient temperature, is liquid, and has solidification strength and economy. In addition, methyl alcohol, ethyl alcohol, etc.
A water-dispersed type in which polymethylene polyphenylisocyanate is partially modified with a lower alcohol ethoxylate obtained by adding 1 to 10 moles of ethylene oxide to a mole thereof is also useful.

The urethane resin may be foamed.
Excessive foaming is not preferable because the pull-out strength of the RP bolt after fixing is reduced.

Next, as the aqueous alkali silicate solution which is a component of the silica resin, water glass usually used for civil engineering is used, and a polyol, a catalyst, a surfactant and the like can be added as required. Further, water can be added for adjusting the viscosity.

As the polyol to be added, those usually used in the production of urethane resins as described above are used, and among them, low molecular polyols such as ethylene glycol, propylene glycol and triethanolamine are preferable.

Examples of the catalyst include dimethyloctylamine, dimethyllaurylamine, N-methylmorpholine,
Dimethylpiperazine, triethylenediamine, imidazole, N-methyldiethanolamine, N, N, N'-
Trimethylaminoethylethanolamine, N-dimethylethanolamine, polyethyleneimine, N, N, N
Amine-based catalysts such as', N'-tetramethylhexamethylenediamine are exemplified.

As the surfactant, any of cationic, anionic, nonionic and zwitterionic surfactants can be used.

The viscosity of the water glass is 1000 mpa
S / 25 ° C. or less, preferably 500 mpa · s / 25
C. or lower is more preferable.

As the isocyanate compound to be reacted with the aqueous alkali silicate solution, those generally used in the production of the urethane resin described above are used, and the viscosity thereof is 100%.
0 mpa · s / 25 ° C. or less is preferable, and 500 mpa · s
s / 25 ° C. or lower is more preferable.

In order to improve the compatibility with the aqueous alkali silicate solution, a part of the isocyanate can be previously reacted with the hydrophilic polyol. For adjusting the viscosity, a low-viscosity diluent such as propylene carbonate and dioctyl adipate can be added.

Next, an example of a method of fixing a GRP bolt in a drilled hole will be described with reference to the drawings. Here, a silica resin composed of an aqueous solution of an alkali silicate and an isocyanate compound is used as a fixing material, but is not limited thereto.

FIG. 1 is a sectional view showing an embodiment of the present invention, in which a GRP bolt 1 inserted into a borehole 2 in a ground 1 is shown.
It indicates 0. FIG. 2 is a cross-sectional view showing a connection state between the GRP bolt 10 and the connection member 20, and FIG.
FIG. 3 is a cross-sectional view showing a state where a connecting member 40 is attached to a P bolt 10.

The GRP bolt 10 is a hollow tubular member as shown in FIGS. 1 and 2, and has a thread formed on the entire outer surface of the side wall to have a male screw shape. In addition, the connection member 20
A substantially annular member having a through hole 21 in the center,
A cylindrical recess 22 is provided coaxially with 1, and a thread is provided on the inner wall of the recess 22 to form a female screw. The GRP bolt 10 is screwed into the recess 22.

The connecting member 40 shown in FIG. 3 is an annular member having a through hole 41, which has a female thread with a thread provided on the inner wall of the through hole 41.
The RP bolt 10 is screwed. Two or more GRP bolts 10 are connected using this connecting member 40 as necessary.

The GRP bolt 10 is manually inserted into a hole 2 provided in the ground 1 in advance. After insertion, GRP bolt 1
The fixing material injection pipe 30 is connected to the end of the hole 0 on the side of the hole opening via the connecting member 20.

The aqueous alkali silicate solution and the isocyanate compound are mixed by a static mixer or the like, and then mixed.
The liquid is sent through the fixing material injection pipe 30 by an injection pump or the like,
It is injected into the hollow portion of the GRP bolt, flows out from the discharge end of the GRP bolt 10 as shown by the arrow, flows around the GRP bolt 10, and fills the inside of the drill hole 2. When the mixture of the two components is completely filled in the drilling hole 2, it overflows from the drilling hole portion, and the injection is stopped when overflow is recognized. Both components react and harden in about 30 seconds to 30 minutes after mixing, and the GRP bolt 10 is integrated with the ground 1.

GRP bolts are usually inserted after drilling holes as described above, but they may be self-drilling if necessary.

Further, the fixing material can be injected into the hole wall of the hole and also penetrate into the underground portion, so-called "forepoling" or "forepiling". In that case, injection pressure is applied to forcibly penetrate the underground portion, or the viscosity of the resin is reduced to facilitate penetration into the ground.

[0041]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Examples 1 to 3 A GRP bolt (a 75% glass fiber / epoxy 25% mixed type hollow GRP bolt manufactured by Catex Co., Ltd.) was drilled at a depth of 32 mm and an angle of 45 ° upward at an angle of 45 ° in the ground. , A bolt outer diameter of 22 mm, an inner diameter of 12 mm, a length of 6 m, and a tensile strength at break of 21.2 t). The GRP bolt was injected from the hollow portion, and was discharged from the tip of the GRP bolt to fill the hole wall of the drilled hole.

After 6 hours, the pull-out strength of the GRP bolt was measured. As a result, each showed an intensity of 10 t or more.

[0044]

[Table 1] .

Comparative Example 1 A hole was drilled in the ground in the same manner as in the example, mortar shown in Table 2 was injected into the hole, and a steel lock bolt (outer diameter 22 mm, length 6 m) was inserted. After 6 hours, the pull-out strength of the rock bolt was measured. As a result, the strength of the mortar was weak, and the rock bolt easily came off.

[0046]

[Table 2] .

[0047]

According to the first aspect of the present invention, since a male screw-shaped GRP bolt having a thread on the surface is used as a lock bolt, the contact area with the fixing material is large, and the integration with the ground is improved. Excellent and stable anchor effect over a long period of time. Further, since the bolt is made of plastic, it is light and durable.

As described in the second aspect, when a fixing material is injected from a hollow portion using a hollow lock bolt, poor mixing that occurs when a capsule-shaped fixing material is used does not occur.
Therefore, the space can be filled without gaps, and the performance of the fixing material such as urethane resin is sufficiently exhibited.

In particular, with the construction as described in claim 3, the connection between the lock bolt and the fixing material injection pipe is facilitated, and since the connecting member is made of aluminum, it is light and high in strength and has corrosion resistance. Also excellent.

According to the construction method of the fourth aspect, the lock bolts can be easily connected to each other, and since the connecting member is made of aluminum, it is light and high in strength, has excellent corrosion resistance, and has a long life. As a result, the effect of stabilizing the ground will be maintained.

According to the fifth aspect of the present invention, since the fixing material mainly comprises an aqueous solution of an alkali silicate and an isocyanate compound, the reaction hardening time is as short as about 30 seconds to 30 minutes, and the fixing material is integrated with the ground. Is fast.

Further, according to the construction method of the sixth aspect, the fixing material permeates into the underground portion, so that the ground stabilizing effect is particularly excellent.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a connection state between a GRP bolt 10 and a connection member 20.

FIG. 3 is a cross-sectional view showing a state in which a connecting member 40 is attached to the GRP bolt 10.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ground 2 ... Drilling 10 ... GRP bolt 20 ... Connection member 21 ... Through hole 22 ... Depression 30 ... Fixing material injection pipe 40 ... Connection member

Claims (6)

[Claims] A rock bolt made of glass fiber reinforced plastic is inserted into a hole formed in the ground, and the rock bolt is fixed to the ground using a resin-based fixing material to stabilize the ground. In the lock bolt method, the lock bolt is a rod-shaped member having a substantially circular cross section, and is a male screw having a thread provided on an outer surface of a side wall. 2. The lock bolt method according to claim 1, wherein the lock bolt is hollow, and the fixing material is injected from the hollow portion. 3. The fixing material injection side end of the lock bolt,
The lock bolt method according to claim 2, wherein the lock bolt construction method is connected to the tube into which the fixing material is injected, via an aluminum female screw connection member. 4. The lock bolt method according to claim 1, wherein the lock bolts are connected to each other via a female screw connection member made of aluminum. 5. The rock bolt method according to claim 1, wherein the fixing material is a silica resin containing an aqueous alkali silicate solution and an isocyanate compound as main components. 6. The method according to claim 1, wherein said fixing material is injected into a hole wall of a hole and penetrates into an underground portion.
The rock bolt method according to any one of Items 1 to 5.