JPH10227200A - Lock bolt method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance integration of ground and a lock bolt by inserting a glass fiber reinforced plastic-made lock bolt in an excavated hole formed in the ground, injecting urethane resin therein and fixing a lock bolt. SOLUTION: After a GRP bolt 10 is inserted in an excavated hole previously formed in the ground by hands, and a hose 30 is connected through a connection member 20 on the side end part of the excavated hole opening part of the GRP bolt 10 to send urethane resin mixing alkaline silicate aqueous solution and a isocyanate component. Urethane resin which is a fixing agent is flowed into the circumference of the GRP bolt 10, the excavated hole 2 is filled to be hardened, and the GRP bolt 10 is integrated with the ground 1. Because the lock bolt and the fixing agent are composed of resin, more excellent stress relaxation than the time when stress is applied on the ground is displayed after the GRP bolt 10 is integrated with the ground, and deformation energy of the ground can be absorbed. In addition, because the GRP bolt 10 is made of glass fiber reinforced plastic, it is lightweight and superior in durability.

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, loose rock has been stabilized by rock bolts in tunnel construction and the like. As a method of integrating the rock and rock bolts, for example, a cutting method formed on the ground is used. The capsule containing the resin was first inserted into the hole wall of the hole, and then the metal lock bolt was pushed in.Then, the capsule was crushed and mixed while applying rotation, and the space between the hole wall and the lock bolt was hardened. A method of filling with a resin is employed. Alternatively, a method has also been adopted in which after a hole wall of a drilling hole provided in advance is filled with cement, mortar, or the like, a lock bolt is inserted and integrated with the ground.

[0003]

However, in the former of such conventional construction methods, it is impossible to insert a resin-filled capsule into a hole when the hole wall is difficult to stand on its own. And the mixing is done only by the rotation of the rock bolt, so it tends to be insufficient,
There was a problem that the performance of the resin was not sufficiently exhibited.

[0004] In addition, the latter has a drawback that it takes a long time to integrate with mortar because the strength of the mortar is low, and in order to solve this, a quick-curing agent is added to cure. If it is accelerated, it hardens and loses fluidity before the lock bolt is inserted after it is injected into the hole, making it impossible to insert the lock bolt or creating a gap between the lock bolt and mortar, There was a problem that the integrity with the mountain was lost.

Further, since the conventional lock bolt is made of metal, it is heavy, easily rusted, and has problems in workability and durability.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art.

That is, in the lock bolt method according to the first aspect, a lock bolt made of glass fiber reinforced plastic is inserted into a hole formed in the ground, and the lock bolt is fixed by injecting urethane resin as a fixing material. Things.

[0008] In the rock bolt method, it is preferable that the lock bolt is hollow, and urethane resin is injected from the hollow portion.

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

Further, the urethane resin may be injected into the hole wall of the hole and penetrate into the underground portion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A glass fiber reinforced plastic lock bolt (hereinafter referred to as a GRP bolt) used in the present invention is obtained by reinforcing a resin such as an epoxy resin or a polyester resin with glass fibers, and has a tensile strength at break. 5t
It is preferable that it is above.

The GRP bolt has an elongated hollow rod shape and has a structure in which both ends are opened. Urethane resin is injected from an opening on the hand side and flows out into a drill hole from an opening on the tip side. Have been like. Although the length is not particularly limited, it is usually about 3 to 6 m, and the length can be adjusted using a joint as needed. However, when a joint is used, it is desirable that the joint portion has a tensile strength at break of 5 t or more.

[0013] One or more through holes through which the urethane resin flows out may be provided on the side wall of the GRP bolt as needed so that the urethane resin can spread more quickly around the bolt. The diameter, number, position, and the like of the through holes may be determined as appropriate according to the viscosity of the fixing agent, the state of the ground, and the like.

As the urethane resin as a fixing material, a two-pack reaction type urethane resin containing a polyol and an isocyanate compound as main components can be used.

Examples of polyols include dihydric alcohols such as 1,3-butanediol, 1,4-butanediol and 1,6-hexanediol; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol Butylene glycol, acetylene glycol, glycerin, trimethylolpropane, diglycerin, castor oil, dehydrated castor oil, sorbitol, sucrose and the like alone or in combination, and polyols obtained by addition-polymerizing an alkylene oxide such as propylene oxide or ethylene oxide. Can be 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 above 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 and polyphenylisocyanate are partially modified with a lower alcohol ethoxylate obtained by adding 1 to 10 moles of ethylene oxide to moles is also useful.

However, since the urethane resin comprising the polyol and the isocyanate compound as described above is expensive, an aqueous alkali silicate solution and a silica resin containing an isocyanate compound as a main component are advantageous.

As the aqueous alkali silicate solution, 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 for the production of the urethane resin 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, those usually used in the production of the urethane resin described above are used.
The viscosity is preferably 1000 mpa · s / 25 ° C. or less, more preferably 500 mpa · s / 25 ° C. or less.

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.

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

A method for fixing a GRP bolt in a borehole using the fixing material comprising the above-described aqueous alkali silicate solution and an isocyanate compound will be described with reference to the drawings.

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.
0 is shown.

The GRP bolt 10 is a hollow tubular member as shown in this figure, and is manually inserted into a drilled hole 2 provided in the ground 1 in advance. After the insertion, the hose 30 is connected to the end of the GRP bolt 10 on the hole opening side via the connecting member 20.

The aqueous alkali silicate solution and the isocyanate component are mixed by a static mixer or the like, and then sent through a hose 30 by an injection pump or the like.
It is injected into the hollow portion of the RP 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 resin is completely filled in the hole 2, the resin overflows from the hole, and the injection is stopped when the overflow is recognized. The urethane resin composed of the water glass component and the isocyanate component reacts and cures in about 30 seconds to 30 minutes after mixing,
The RP bolt 10 is integrated with the ground 1.

The GRP bolts are usually inserted after drilling holes as described above, but they can be of a self-drilling type if necessary.

It is also possible to construct a so-called "hole poling" or "hole piling" in which the urethane resin is injected into the hole wall of the hole and also penetrates into the underground portion. 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.

As described above, in the lock bolt method of the present invention, since both the lock bolt and the fixing material are made of resin, stress is applied to the ground after the lock bolt is integrated with the ground. In this case, compared with the case where the conventional steel lock bolt is fixed with mortar or the like, the stress relaxation property is excellent, and the deformation energy of the ground can be absorbed.

[0035]

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 hollow GRP bolt manufactured by Catex Co., Ltd.) was drilled in the ground at a diameter of 32 mm and an angle of 45 ° upward at an angle of 45 ° upward. , A bolt outer diameter of 22 mm, an inner diameter of 12 mm, a length of 6 m, a tensile strength at break of 31.6 t), a urethane resin composed of each of the components A and B shown in Table 1 was mixed with a static mixer, and a GRP bolt was formed by an injection pump. Inject from the hollow, G
The RP bolt was discharged from the tip and filled in the hole wall of the hole.

After 6 hours, the pull-out strength of the GRP bolt was measured. As a result, all showed a strength of 5 t or more.

[0038]

[Table 1] .

Comparative Example 1 A hole was drilled in the ground in the same manner as in the example, a 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.

[0040]

[Table 2] .

[0041]

According to the method of the first aspect, since both the GRP bolt and the fixing material are made of resin, the stress on the ground is alleviated, and the ground stabilizing effect is excellent. Also,
Since the GRP bolt is made of glass fiber reinforced plastic, it is light and durable.

According to the method of the second aspect, since the GRP bolt is hollow and the fixing material can be injected from the hollow portion, the mixing failure that occurs when using a capsule as the fixing material does not occur. Therefore, the space can be filled without gaps, and the performance of the urethane resin is sufficiently exhibited.

According to the method of claim 3, since the urethane resin contains an aqueous solution of alkali silicate and isocyanate as main components, it is inexpensive and has a reaction curing time of about 3 hours.
Since it is as short as 0 seconds to 30 minutes, integration with the ground is fast.

Furthermore, according to the construction method of claim 4, since the urethane resin penetrates into the underground portion, 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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ground pile 2 ... Drilling 10 ... GRP bolt 20 ... Connection member 30 ... Hose

Claims (4)

[Claims] 1. A rock bolt method comprising inserting a lock bolt made of glass fiber reinforced plastic into a hole formed in a ground, and fixing the lock bolt by injecting urethane resin as a fixing material. 2. The lock bolt method according to claim 1, wherein the lock bolt is hollow, and the urethane resin is injected from the hollow portion. 3. The rock bolt method according to claim 1, wherein the urethane resin is an aqueous solution of an alkali silicate and a silica resin containing isocyanate as a main component. 4. The rock bolt method according to claim 1, wherein the urethane resin is injected into a hole wall of the drilled hole and also penetrates into an underground portion.