JPH03241114A - Bedrock solidifying injection bolt and bedrock stabilization method by using the same - Google Patents

Abstract

PURPOSE:To promote the economic efficiency and work efficiency by having a difference in thickness between the front and rear sections, providing a step to the joining section, fixing a stationary mixer to form an injection bolt, and inserting the bolt into a hole bored into a bedrock to pour a quick hardening hard foamable urethane resin. CONSTITUTION:In an injection bolt A, there is a difference in thickness between the front section 2 and rear section 1, a step 5 having a rapidly changed thickness is formed on the boundary, and one-piece seamless working is performed. A stationary mixer 6 is fixed to the step without requiring any special anchorage so that a collar of the stationary mixer 6 is interlocked. A plurality of holes are bored into the bedrock to insert the injection bolts A into them. Then, a chemical fluid constituted of quick hardening hard foamable urethane resin having polyol more than hydroxyl valence 500KOHmg/g and poly-isocyanate compound having poly-isocyanate more than two groups for the main ingredients is injected from an opening section 3 of the injection bolt A. In that case, the polyol and poly-isocyanate compound are so mixed that NCO/OH equivalent ratio becomes 0.5/1 - 10/1, and such quick hardening hard foamable urethane resin as initial mixing viscosity is 1,000cp/less than 20 C, hardening time is 5 seconds - 10 minutes, foaming magnification is 1 - 30 times and compressive strength has 1 - 400kg/cm<2> is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to cracks in rock, ground, artificial structures, etc. (hereinafter referred to as "rock" in this specification),
Rock consolidation injection bolts ( (hereinafter referred to as "injection bolt").

The present invention also has a hydroxyl value of 500K as an injection grout.
The present invention relates to a rock stabilization method in which a two-component hard urethane foam made of polyol and polyisocyanate having an OHmg/g or more is used in combination with the injection bolt.

The present invention further provides an injection grout in which a polyether polyol in which a part of the active hydrogen of the terminal hydroxyl group has been substituted with an alkali metal and/or an alkaline earth metal is used as a polyol component by dicarboxylic acid anhydride in the absence of water. A rock stabilization method in which a modified polyether polyol obtained by the treatment is used as a modifier having an isocyanate trimerization catalyst activity, and a bifoamed isocyanurate-based hard urethane in combination with a polyisocyanate is used in combination with the injection bolt. Regarding the law.

[Problems to be solved by conventional technology and the invention] Conventionally, the presence of faults and rocks that easily peel off at tunnel faces has weakened the ceiling, causing problems in terms of safety, work, and production. Something happened.

For this reason, a predetermined chemical solution is injected into such soft rock to solidify it, thereby preventing cave-ins, falling rocks, etc., and stabilizing the rock.

For example, Japanese Patent Publication No. 83-83687, Japanese Patent Publication No. 63
-63888, JP 63-7413, JP 63-7490, JP 83-7491, JP 63-8477, and JP 63-3
Publication No. 5913, etc. describes a static mixer for a two-component foaming hard urethane chemical solution, a hollow iron pipe equipped with a check valve, etc.
A construction method is described in which the material is injected into an unstable rock layer through a diameter of 25+ am and a length of about 3 m, and then consolidated.

However, the injection vibrator used in conventional construction methods has the structural defects described below, and has a low resistance to the gravity and various stresses of other mountains, making it difficult to sufficiently stabilize unstable ground and rock layers. I can't wander around.

In other words, with conventional injection bolts, in order to mix the two liquids through a static mixer inside the bolt, it is necessary to insert and fix a static mixer in the center or front of the bolt, and as a result, the center and front parts of the bolt are separated. Various measures have been taken, such as making it possible to connect by screwing the screws together, and creating protrusions in between to fix static mixers and check valves.

However, with such separate screw-in type bolts, the yield strength around the screw joint is small, making it difficult to sufficiently stabilize the rock layer as desired. In order to compensate for this decrease in yield strength, it is necessary to increase the wall thickness of the hollow bolt or to upgrade the grade of steel used, but this is not only uneconomical but also reduces workability. Put it away.

In view of the above-mentioned circumstances, the inventors of the present invention have made extensive research and efforts to solve the problems of the conventional injection bolts, and as a result, the present inventors have found that the bolts are economical and easy to work with, as described in detail below. We also succeeded in developing an excellent hollow bolt with holes.

That is, in the injection bolt of the present invention, the wall thickness is different between the front part and the rear part, and a difference is provided in the connecting part, and the stationary mixer is fixed to this difference. In this way, unlike conventional bolts, it is a single bolt without a joint for fixing a static mixer or a check valve, and the front part of the bolt with the chemical discharge hole is thick, and the rear part of the bolt is relatively thin.

On the other hand, inorganic grouts such as cement milk and water glass have been conventionally used as injection chemicals, but since these inorganic grouts are a dispersion of cement particles, they have a high viscosity and cause the formation of small cracks in the rock. The purpose of stabilizing the rock layer and fixing the inserted bolt cannot be achieved due to the fact that it does not penetrate to the depths and requires a long period of time to develop strength, resulting in poor work efficiency and the ability to develop strength in a short period of time.

In addition, as an organic injection chemical solution, for example,
Publication No. 8477 describes a two-component foamed urethane resin with a hydroxyl value of 450 to 250 KOJI/g as a polyol component.
, isocyanate group content as isocyanate component: 1
Systems with polyisocyanates of 8-48% by weight and molecular weights of 174-2000 have been introduced. However, these polyols with hydroxyl value range have a molecular weight range of about 250 to 900 when converted to diol-tetraol, and although they are in the low molecular weight range, they have high viscosity. This necessitates the use of low boiling point solvents, which is undesirable from the standpoints of occupational safety and health and environmental pollution. Furthermore, the density of crosslinks such as urethane bonds and urea bonds is small, and the strength of the solid body is low, making it difficult to stabilize the rock layer. The fixation of the rock bolt is also not sufficient. Additionally, these chemical solutions have the disadvantage of being inherently flammable.

[Means for Solving the Problems] The injection bolt of the present invention is a hollow bolt that is integrally processed without a seam in the middle portion, and has a thick front portion and a thin rear portion having an opening for grout injection. It consists of
A stationary mixer is provided at a step at the boundary between the front part and the rear part, and a plurality of injection holes for mixed grout are formed in the front part.

In addition, the rock stabilization method of the present invention includes: (1) Drilling a plurality of holes in the rock at predetermined intervals, inserting the injection bolt into the hole, and inserting a hydroxyl value of 500 KOHmg/ A rock stabilization method comprising injecting a chemical solution consisting of a fast-curing rigid foamed urethane resin containing as essential components a polyol having a molecular weight of at least 100 g and a polyisocyanate compound having two or more isocyanate groups, the method comprising: when the NCO/OH equivalent ratio is 0
．． 5/1 to 10/1, and the fast-curing rigid foam urethane resin has an initial mixed viscosity of 1000 cP/1.
The temperature is 20°C or less, the curing time is 5 seconds to 10 minutes,
The foaming ratio is 1 to 30 times, and the compressive strength is 1 to 4.
00) have a performance of cg/cj, or (2) drill a plurality of holes in the rock at predetermined intervals, insert the injection bolt into the hole, and from the opening of the bolt, (
(B) A modified polyol obtained by treating a polyether polyol in which a part of the active hydrogen of the terminal hydroxyl group has been replaced with an alkali metal and/or an alkaline earth metal with a dicarboxylic acid anhydride in the absence of water; ) A rock stabilization method consisting of injecting a chemical solution consisting of a two-component fast-setting hard foaming isocyanurate-based urethane resin whose essential components are polyisocyanate, the four components and (
8) Components NGOlo) 1 equivalent ratio is 0.5/1 to 10
/1, and the fast-curing hard foaming isocyanurate-based urethane resin has an initial mixed viscosity of 1000 cP.
/20℃ or less, and the curing time is 720℃ for 5 seconds to 10 minutes.
It is characterized by having an expansion ratio of 1 to 30 times and a compressive strength of 1 to 400 kg/c-.

[Example code] First, the injection bolt of the present invention will be explained in detail.

FIG. 1 is a schematic explanatory diagram of an embodiment of the injection bolt of the present invention.

In FIG. 1, the circle is an injection bolt according to an embodiment of the present invention, and the inside of the bolt is composed of a thin rear part (fl) and a thick front part (2). The bolt is a hollow bolt with a seamless middle part.

The outer diameter and length of the bolt are not particularly limited in the present invention, but are approximately 25 to 30 m1 and 2 to 30 m1, respectively.
The standard is 4m. Depending on the purpose, the inside of the bolt may be made of plastics such as polyethylene or hard vinyl chloride resin, light metals such as aluminum or brass, iron, or steel. When the purpose is to stabilize and strengthen unstable rock or ground by the method, it is preferable to use various steel materials from the viewpoints of yield strength, rust prevention, and durability. In particular, carbon steel pipes are preferable from the viewpoint of strength and proof stress, such as JIS
Carbon content specified in G-3455 0.45-0
．． Particularly preferred is 55% STKM17c.

The thin-walled rear part (1) has at its end an opening (3) for grouting, to which a joint (not shown) with a check valve is connected. , a chemical solution to be described later is injected. The wall thickness of the rear part (1) should be in the range of 3 to 5 degrees, especially 3.5 to 5 degrees, from the viewpoint of stress, workability, economic efficiency, etc.
Preferably, it is in the range of 4.5 degrees.

A plurality of holes (4) for injecting mixed grout into the rock around the four bolts are formed in the thick front part (2). The number of holes (4) should be 8 to 8 in order to penetrate the entire area in the injection direction (axial direction) and from the viewpoint of the proof strength of the bolt.
Twelve (usually eight) holes are drilled from about half of the inside of the thickness to the tip, at approximately equal intervals on the top, bottom, left and right in the thickness direction. In addition, the diameter of the hole (4) is the proof strength of the bolt,
From the viewpoint of the discharge flow rate of the chemical liquid, etc., it is preferably approximately 7 to 9 degrees.

The end of the front part (3) has a threaded structure, and a conical tip stopper (9) is screwed into it.
The ends are sealed. In addition, the wall thickness of the front part (2) is 4
~7 mm, particularly preferably 5~6+ll11.

At the boundary between the front part (2) and the rear part (1), a step part (5) whose wall thickness changes rapidly is formed.
) is adapted to engage with the collar of a stationary mixer (6), which will be described later.

The ratio of the wall thickness of the front part (2) and the rear part (1) is preferably about 1.1 to 2.3:1 in terms of strength, and even if it is larger or smaller than this, it is economical and This may cause problems with durability, etc.

One of the features of the injection bolt of the present invention is that the stepped portion (5
), the stationary mixer (6) can be fixed naturally without the need for special fixing devices.

In other words, two-component heating parts are formed into a spiral shape, assembled into a cylindrical shape, and have a brim with a slightly larger outer diameter on the front side (grout injection side) (for example, the one made by JP-A-Sho). 83-7413 and JP-A No. 83-7490), the cylindrical part (the outer diameter of the sword is connected to the front part of the hollow bolt (
2), and the brim (8 mm).
) is formed so that the outer diameter of the front part ('2I) is larger than the inner diameter of the front part ('2I) and smaller than the inner diameter of the rear part (1) to the extent that it can be smoothly inserted and removed.

When the static mixer (6) with such a device is inserted into the injection bolt (4) of the present invention through the opening (3) and then the chemical solution is pressurized with a pump, the static mixer (6) will naturally fill the stepped portion ( 5), both liquids are well mixed and the injection work can be carried out smoothly.

The chemical solution injected using the injection bolt of the present invention includes 2
Component-type foamed rigid polyurethane is preferable in terms of permeability, rapid hardening, and stabilization effect, and the following chemical solutions are particularly excellent.

That is, it is a two-component rigid foamed urethane resin that exhibits low viscosity and high strength physical properties, and has a hydroxyl value of 500 KOHmg/
A combination of a polyol and a polyisocyanate having a viscosity of 1,000 cP/20° C. or higher and a viscosity of 1,000 cP/20° C. or higher is preferable.

Hydroxyl value 500 KOtl+++g/ Viscosity 1 at g or more
000 cP/20℃ or less polyol component:
■ 1,3- or 1,4-butanediol, 1,3-
Or dihydric alcohols such as 2.3-butylene glycol, 1,6-hexanediol, pentylene gelicol, and hexylene glycol alone or addition polymerized with alkylene oxides such as ethylene oxide and propylene oxide with a hydroxyl value of 500 kOH/ diols of g or more, ■ ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, diethylene glycol, tributylene glycol, glycerin,
Trimethylolpropane, mono, jetanolamine,
Polyols with a hydroxyl value of 500KOH+I1g/g or more, such as triethanolamine, diglycerin, etc. alone or added and polymerized with alkylene oxides; ■ Polyols with a hydroxyl value of 500KOH+I1g/g or more, which are made by addition-polymerizing aniline, ethylenediamine, etc. with ethylene oxide, propylene oxide, etc. / g or more of amine polyol, ■ alcohols such as methanol, ethanol, propatool, butanol, hexanol alone or by addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to a hydroxyl value of 500 KO.
Examples include monools with Hmg/g or more. These polyols may be used alone or in combination.

Next, examples of the polyisocyanate to be combined with these polyols include tolylene diisocyanate, crude tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylisocyanate, and the like alone or in mixtures. In addition, these organic polyisocyanates can be mixed with water, the polyols shown in ① to ① above, and further with a hydroxyl value of 500 KOHmg/g.
It may also be used in the form of a so-called NGO group-terminated urethane prepolymer modified with the above polyols. Furthermore, a catalyst may be added to a single organic polyisocyanate to form a dimer or trimer.

A known method can be employed to obtain a predetermined foamed rigid urethane composition by combining the polyol and organic polyisocyanate.

That is, first, a polyol component having a hydroxyl value of 500 KOHmg/g or more and a viscosity of 1000 cP/20°C or less,
Trichloromonofluoromethane as a blowing agent if necessary;
A low boiling point organic solvent such as dichlorodifluoromethane, methylene chloride, trichloroethane, hexane, etc., water, nitroethane, formamide, urea, boric acid, borax, etc. are blended.

Further, as surfactants and foam stabilizers, for example, siloxane-oxyalkylene copolymer organopolysiloxane, nonylphenol ethoxylate, etc. are blended.

In addition, various catalysts such as dibutyltin laurate, tin octylate, triethylenediamine, triethylamine, etc. are added to promote the reaction with the polyisocyanate.

Furthermore, phosphorus, halogen compounds, antimony dioxide, aluminum hydroxide, etc. may be added to exhibit a flame retardant effect, and organic diluents such as dibutyl phthalate, dioctyl phthalate, geltaric acid methyl ester, Glycols, acetate esters of cellosolves, etc. may be added.

The reaction ratio between the hydroxyl group in the polyol component and the NGO group in the polyisocyanate component, that is, the NC010!1 equivalent ratio is 0.5/1 to 10/1, and 0.971 to 2/1.
It is preferable that The polyol component and polyisocyanate component are mixed uniformly by a static mixer inserted into an injection bolt, and then injected into a predetermined rock mass or fractured zone layer.

In order to stabilize the rock solidification, the curing time is 5 seconds to 10 minutes.
Foaming ratio is 1 to 30 times, compressive strength is 1 to 400 kg/c
It is necessary that the resin exhibits the properties d.

Next, as a useful injection grout, which is one of the features of the method of the present invention, we will introduce a special two-component type fast-setting hard foaming isoplastic,
The point of using cyanurate-based urethane resin will be explained.

That is, as the polyol component (Component (2)), a polyether polyol in which a part of the active hydrogen of the terminal hydroxyl group has been replaced with an alkali metal and/or an alkaline earth metal is prepared by treating it with a dicarboxylic anhydride in the absence of water. A modified polyether polyol is used as a modifier having isocyanate trimerization catalytic activity, and a polyisocyanate is used as the former component. Then, the (4) component and the 0) component are NGO101 + equivalent ratio 0.5 /1 ~ 10 /
1. Mix and inject preferably at a blending ratio of 2/l to 8/l,
Initial mixed viscosity of both components: 1000 cP/20°C or lower Curing time: 5 seconds to 10 minutes/20°C, foaming ratio of 1 to 30 times, compressive strength of 1 to 400 kg/(1!-) Fast-curing rigid foam with consolidation performance A polyisocyanurate-based urethane resin is used.The polyisocyanurate-based urethane resin composition using the modified polyether polyol can be produced by the method described below, for example, as described in Japanese Patent Publication No. 57-42646. I can do it.

First, a special modified polyether polyol with isocyanate trimerization catalytic activity is produced. That is, it is obtained by treating a polyether polyol in which a portion of the active hydrogens of the terminal hydroxyl groups are substituted with an alkali metal and/or an alkaline earth metal with a dicarboxylic acid anhydride in the absence of water.

First, as a polyether polyol in which a part of the active hydrogen of the terminal hydroxyl group is substituted with an alkali metal and/or an alkaline earth metal, for example, an organic compound having at least two or more active hydrogen groups (hereinafter referred to as "initiating A polyether polyol containing a catalyst obtained by adding an alkali metal and/or alkaline earth metal hydroxide as a catalyst to a compound (referred to as "agent"), subjecting the mixture to heating and depressurizing treatment, and then addition-polymerizing alkylene oxide. (
Hereinafter, referred to as "crude polyether polyol"), crude polyether polyol is further added with an alkali metal and (
or) polyether polyol obtained by heating and reducing pressure after adding an alkaline earth metal hydroxide;
After adding an alkali metal and/or alkaline earth metal hydroxide to a polyether polyol obtained by purifying the crude polyether polyol to remove the catalyst (hereinafter referred to as "purified polyether polyol"), it is heated under reduced pressure. Examples include polyether polyols and mixtures thereof.

Examples of the initiator include low-molecular polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and sucrose; alkanolamines such as monoethanolamine, jetanolamine, and triethanolamine; Examples include aliphatic polyamines such as ethylene diamine, diethylene triamine, and triethylene teleramine, aromatic polyamines such as tolylene diamine, 4,4'-diphenylmethane diamine, and phenylene diamine, and aromatic polyhydric alcohols such as bisphenol A1 novolak. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, etc., and one or more of these are added to the initiator in the form of a random or block copolymer. The polyether polyol obtained in this way, in which a part of the active hydrogen of the terminal hydroxyl group is substituted with an alkali metal and/or an alkaline earth metal, usually has an average molecular weight of 1 before modification.
00-20,000, preferably 100-io, ooo
, the number of hydroxyl groups is 2 to 8, and the content of oxyethylene chains in the oxyalkylene chains is 0 to 100%.

Next, the alkali metal and/or alkaline earth metal hydroxides to be added to the initiator as a catalyst or added to the crude polyether polyol or purified polyether polyol include sodium, potassium,
Examples include hydroxides of calcium and magnesium.

The amount of the alkali metal and/or alkaline earth metal hydroxide added is 100 parts by weight of a polyether polyol in which a part of the active hydrogen of the terminal hydroxyl group has been replaced with an alkali metal and/or an alkaline earth metal. They are 0.05 to 10 parts by weight as a single metal, preferably 0.1 to 10 parts by weight.
Add so as to contain 5 parts by weight.

What is particularly important in the production of modified polyether polyols is to use hydroxides of alkali metals and/or alkaline earth metals as the alcoholade of polyether polyols, and to minimize the amount of hydroxides. . If the conversion to alcoholade is insufficient, when the dicarboxylic anhydride is added and heat treated, a large amount of free salt will be present, resulting in a result that does not meet the purpose of trimerizing the isocyanate.

In order to increase the alcoholade conversion rate as much as possible, it is possible to increase the stirring efficiency, heating temperature and degree of depressurization, and to lengthen the treatment time. Increasing the conversion rate is also an effective method. A general method for increasing the primaryization rate of terminal hydroxyl groups is to increase the amount of ethylene oxide added to the terminals of the polyether polyol.

Next, the dicarboxylic acid anhydride used to treat the polyether polyol in which a part of the active hydrogen of the terminal hydroxyl group has been substituted with an alkali metal and/or an alkaline earth metal in the presence of water is, for example, succinic anhydride, glutaric anhydride. Saturated aliphatic dicarboxylic acid anhydrides such as acids, fumaric anhydride,
Examples include unsaturated aliphatic dicarboxylic acid anhydrides such as maleic anhydride, aromatic dicarboxylic acid anhydrides such as phthalic anhydride, and alicyclic dicarboxylic acid anhydrides such as cyclohexanedicarboxylic anhydride, either alone or in combination of two or more. I don't mind if you do. The amount of these dicarboxylic acid anhydrides added is determined by the amount of alkali metal and/or alkaline earth metal 1 The amount is 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, and the heating conditions are 30 to 150°C.
, preferably at 60 to 120°C for 1 to 3 hours.

Monocarboxylic anhydride (instead of dicarboxylic anhydride)
For example, when using an acid anhydride other than a secondary basic acid, such as acetic anhydride), tricarboxylic anhydride (e.g., trimellitic anhydride), or tetracarboxylic acid anhydride (e.g., pyromellitic anhydride), the free salt is Produce a large amount or
Modified polyether polyols are polymerized by esterification, and none of them can achieve the trimerization effect of isocyanate.

When the modified polyether polyol thus obtained is used as a modifier with isocyanate trimerization catalytic activity, a cured product mainly consisting of a non-foamed to foamed modified polyisocyanurate bond is formed. The NCO/OH reaction equivalent ratio with the polyisocyanate of component B is generally preferably 2 or more, but if heat resistance, flame retardance, etc. are not severely required, the reaction with a polyisocyanate with an equivalent ratio of 2 or less is preferable. Good solids can be obtained even if That is, a good cured product can be obtained even if a polyol that reacts at an equivalent ratio of about 0.8 to 1.2 and has urethanization catalyst activity for so-called hard urethane foams is used.

In addition, when reacting with polyisocyanate at an equivalent ratio of 2 or more, in addition to the modified polyether polyol, if necessary, other known isocyanate trimerization catalysts or urethanization catalysts may be used. Various known active hydrogen compounds can also be used in combination as agents.

Next, the polyisocyanate of component B to be combined with component A to form a cured polyisocyanurate product includes, for example, 4,4'-diphenylmethane diisocyanate crude product (hereinafter referred to as "crude HDI J"), polymethylene polyphenyl Isocyanate (PAPI),
Tolylene diisocyanate crude (crude TDI), 2.
Polyisocyanates such as 44 lylene diisocyanate, 2.64 lylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and mixtures thereof, as well as prepolymers of these polyisocyanates and polyols and/or prepolymers thereof and mixtures of the above-mentioned polyisocyanates.

If a foamed cured polyisocyanurate product is to be formed, foaming agents such as trichloromonofluoromethane (F-11), dichlorodifluoromethane (['-12), and methylene chloride may be used, if necessary. Low boiling point organic solvents, water, nitroethane, formamide, urea, boric acid, borax, etc. are added, and the amount added is generally 0.
．． It is blended into component A so that it is contained in an amount of 5 to 5% by weight.

In addition, in order to improve the compatibility and foam regulating properties of components A and B, surfactants such as siloxane-oxyalkylene copolymer (hereinafter referred to as "silicone oil") are used.
, organopolysiloxane, oxyethylated alkylphenol, oxyethylated higher alcohol, ethylene oxide-propylene oxide block copolymer, etc. may be added, and are generally blended into component A in an amount of 1 to 10% by weight.

Next, liquid or powder additives that are added to improve the sealing effect and consolidation strength of the cured product, as well as to support the flame retardant effect, include halogen compounds such as phosphorus, bromine, and chlorine, and hydroxide. aluminum, boric acid, gypsum,
There are slaked lime, calcium carbonate cement, carbon, bentonite, clay, coloring agents, etc., and the amount of these added is A.
The total amount of both SB components is preferably 0 to 100% by weight. These liquid or powder additives can be blended into either the A component or the B component, but in consideration of product stability due to moisture contamination, it is preferable to blend them into the A component side.

Next, using a hard urethane resin or a polyisocyanurate urethane resin composition with such a special composition and the injection bolt of the present invention, it is possible to inject into cracks, voids, fractured zones, etc. of rock, and stabilize the solidification. A known method is adopted.

The injection bolt and rock stabilization method of the present invention will be described below based on Examples, but the present invention is not limited to these Examples.

Example 1 and Comparative Example 1 A load bearing capacity test was conducted on the injection bolt of the present invention and the conventional injection bolt having the specifications shown in Table 1. The results are shown in Table 1.

In addition, 20 holes with a depth of 3 m were drilled at 2 m intervals in the rock having a fracture zone using a 42 mmφ bit leg auger.

The diameter of the drilled hole was about 50 mm, but the inside of the hole was blocked by something called slag.

The bolt of Example 1 was inserted into the hole prepared 10 times, and was able to be inserted reliably all 10 times. on the other hand,
I also tried inserting the bolt of Comparative Example 1 10 times, but in each case a crack occurred in the central joint, and 6 out of 10
The book has been destroyed.

[Left below] Example 2 Holes were drilled at 2m intervals at angles of 25 to 35 degrees using a 42m11φ Bittreng auger in the top of a tunnel with a fracture zone.
(at an angle to the tunnel excavation direction), and injected the injection bolt of the present invention (outer diameter 27.2 mvA) into the drilled holes.
sInner diameter 18.2mm (front part), 19.2mm (
rear part), length 3m, static mixer and check valve internal)
was inserted, and a quick-set cement was pressed into the mouth for approximately 30 cm to seal it.

Then, the following two-component rigid foamed urethane resin was injected from each fixed injection hole at an injection pressure of about 5 to 10 kg/cdG, and about 100 to 150 kg of drug 'tfM per hole.

In addition, each component in the following components A and B is expressed in parts by weight.

A component Polyol component Addition polymerization of ethylene oxide to glycerin (molecular weight 300, viscosity 160cP/20℃) 40 Dipropylene glycol (viscosity 80cP 725℃) 60 Water
1
．． 0 Foam stabilizer DKS Shi! J Con D332 2
．． 0DABCO33LV L,
0 Dibutyltin dilaurate 0.2 Mixed polyol average hydroxyl value (■KOH/g) 727B component C-MDI (Myriotate MR-100) 2
08 Methylene chloride 2° Blending (weight) ratio: A component/B component - 104, 2/213 Mixed viscosity (
cP /20℃) 11°Cream time: 33 seconds Gel timeco 40 seconds Rise time: 52 seconds Approximately 90 minutes after injecting the chemical solution, the improvement state of the ground was investigated by excavation, and the consolidation area was 2 m deep. thickness 2
It had a semicircular shape of m, and was solidified and stabilized.

When the injected solidified part was sampled in a cylindrical shape of φ5cm x IOcm using a sampler and the -axial compressive strength was measured, 14
It was 0 kg/c-. Note that sampling was not possible in the unimproved area due to the fractured zone.

As a result, the effectiveness of the injection bolt of the present invention was fully proven, and it was found that a consolidated stabilizing layer having a strength of 181 or more was formed in conjunction with the bolt yield strength of Example 1.

Example 3 and Comparative Example 2 In order to stabilize the tunnel ceiling part of the granite fracture zone having large voids, stabilization was carried out by injection of a two-component rigid foamed polyisocyanurate-based polyurethane resin (
Example 3). For comparison, a general rigid urethane foam formulation was also tested (Comparative Example 2). The construction method was the same as in Example 2.

That is, one injection hole (Nα1 to 10) with a depth of 2 m was made at approximately 2 m intervals on the top plate using a φ42 bit leg auger.
0 holes were drilled. The drilling angle was 20°. An iron lock bolt of the present invention similar to that in Example 2 was inserted into the hole thus obtained, and the mouth portion was sealed in the same manner as in Example 2.

For each injection hole, add 100 to 15 ml of the chemical solution shown in Table 2.
0 kg (injection pressure 2-10 kg/c-) was injected and sealed. Approximately 90 minutes after injecting the chemical solution, we excavated and investigated the area around the injection hole to confirm the stabilization status of the ground, and found that the area had consolidated in a semicircular shape approximately 2 m deep and 2 m thick. Moreover, even large voids were sealed well with high density.

For reference, a core sample was taken of a portion where urethane resin was sealed and solidified in a particularly large gap, and the compressive strength was measured and a combustion test was conducted.

[Blank below] From Example 3, a modified polyol and polyisocyanate treated with dicarboxylic acid anhydride, and if necessary, a special polyisocyanurate-based rigid foamed urethane chemical solution containing a flame retardant were used in combination with the injection bolt of the present invention. By injecting it into the rock fracture zone, it is possible to form a solidified material mainly consisting of a flame-retardant isocyanurate structure and stabilize the rock mass, which is extremely useful in tunnel excavation work. One thing has been proven.

[Effects of the Invention] As explained above, since the injection bolt of the present invention does not have a seam in the middle part, it is possible to economically produce a bolt with excellent yield strength. In addition, the rock stabilization method of the present invention using such injection bolts can be applied to fracture zones, unstable rock,
It is possible to improve the ability and efficiency of strengthening the stabilization of the ground layer, and when used in combination with low molecular weight, low viscosity injection chemicals, and chemicals that form polyisocyanurate solids, it can improve permeability,
High-strength solids, flame retardance, etc. were added, and we were able to establish a technological improvement in the stability and reinforcement of rock mass.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an embodiment of the injection bolt of the present invention. (Main symbols in the drawing) (A): Injection bolt (1); Rear part (2): Front part (5): Step part (6): Stationary mixer

Claims (1)

[Scope of Claims] 1. An integrally processed hollow bolt with no seam in the middle portion, consisting of a thick front part and a thin rear part having an opening for grout injection. 1. An injection bolt for rock consolidation, characterized in that a stationary mixer is provided at a stepped portion at the boundary between the two parts, and a plurality of injection holes for mixed grout are formed in the front part. 2. The injection bolt for rock consolidation according to claim 1, further comprising a check valve provided inside the bolt on the side of the opening of the static mixer. 3. A plurality of holes are drilled at predetermined intervals in the rock, the injection bolt according to claim 1 is inserted into the hole, and two polyols and isocyanate groups having a hydroxyl value of 500 KOHmg/g or more are inserted through the opening of the bolt. A rock stabilization method comprising injecting a chemical solution made of a fast-curing hard foamed urethane resin containing a polyisocyanate compound having the above as an essential component, wherein the polyol and the polyisocyanate compound have an NCO/OH equivalent ratio of 0.5. /1 to 10/1, and the fast-curing rigid foam urethane resin has an initial mixed viscosity of 1000 cP/20°C or less, a curing time of 5 seconds to 10 minutes, and an expansion ratio of 1 to 10/1. A rock stabilization method characterized by having a compressive strength of 1 to 400 kg/cm^2. 4. Drill a plurality of holes at predetermined intervals in the rock, insert the injection bolt according to claim 1 into the holes, and discover from the opening of the bolt that (A) a part of the active hydrogen of the terminal hydroxyl group is an alkali metal. and (or) a modified polyol obtained by treating a polyether polyol substituted with an alkaline earth metal with a dicarboxylic anhydride in the absence of water, and (B) a polyisocyanate as essential components.
A rock stabilization method consisting of injecting a chemical solution made of a component-type fast-setting hard foaming isocyanurate-based urethane resin, wherein the (A) component and (B) component are mixed at an NCO/OH equivalent ratio of 0.5/1. ~10
/1, and the fast-curing hard foaming isocyanurate-based urethane resin has an initial mixed viscosity of 1000c.
P/20℃ or less, curing time is 5 seconds to 10 minutes/20
℃, a foaming ratio of 1 to 30 times, and a compressive strength of 1 to 400 kg/cm^2.