Grouting chemical composition for rock mass consolidation and formed body

Abstract

To provide a grouting chemical composition for rock mass consolidation, which can obtain stable workability and reactivity without being affected by moisture even under an environment with much leaked water or spring water, and which can ensure resin strength by controlling foamability for ground reinforcement in chemical injection and tunnel excavation.SOLUTION: A grouting chemical composition for rock mass consolidation comprises a polyol component (A) and a polyisocyanate component (B). The polyol component (A) comprises a sodium silicate aqueous solution (A-1), organic polyol (A-2) having three or more functional groups and a molecular weight of 200 or less, and a tertiary amine catalyst (A-3) having one active hydrogen. The polyisocyanate component (B) comprises a mixture of diphenylmethane diisocyanate and polyphenyl polymethylene polyisocyanate, and a reaction product of the mixture with polyol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a chemical grouting composition that can be used even in environments with a lot of spring water or leaks. [Background technology]

[0002] One method for strengthening unstable rock mass or unstable ground is the rock bolting method, which stabilizes the surrounding ground after tunnel excavation. This method aims to protect the tunnel structure by fixing and securing bolts with a chemical solution. High-strength inorganic materials such as mortar have been used as the injection solution for consolidating rock mass. However, inorganic materials such as mortar require a long time to develop strength, which makes their work inefficient. Furthermore, there are problems with the material flowing into the water in the event of water leaks or springs.

[0003] Currently, tunnel excavation is being carried out in areas prone to water leaks and springs, and there are increasing cases of injecting chemicals to solidify rock under flowing water.However, water contamination by the chemicals and water leakage during injection are hindering the efficiency and safety of tunnel excavation work, and improvements are being called for.

[0004] In order to solve these problems, an injection liquid obtained by combining an aqueous silicate solution called water glass, which is an inorganic-organic composite soil stabilization liquid, and a polyisocyanate composition is used.

[0005] For example, Patent Document 1 discloses that by using a polyol component containing an aqueous silicate solution and a tertiary amine catalyst, and an isocyanate component containing diphenylmethane diisocyanate having an oxyalkylene chain as a grouting solution for rock consolidation, hardening and resin strength can be achieved in a short time, and high resin strength is observed due to a low expansion ratio. However, since the polyol component does not contain an organic polyol component, it has poor miscibility with polyisocyanate, raising concerns about water pollution due to elution into water.

[0006] Patent Document 2 discloses that, by using a silicate solution, a tertiary amine catalyst, and a polyol component containing glycerin or an amino group-containing polyol as the polyol component, and an isocyanate component containing diphenylmethane diisocyanate as an injection liquid for rock consolidation, it is possible to achieve hardening and strength development in a short time, as described above. However, this polyol composition has high foaming properties, making it difficult to ensure high resin strength, and there are concerns that leakage cannot be suppressed under running water, making it difficult to ensure efficiency and safety during work. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 4-318096 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-19959 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above-mentioned background art, and aims to provide a liquid grout composition for rock consolidation that provides stable workability and reactivity without being affected by moisture even in environments with frequent water leaks and springs, and that ensures resin strength by controlling foaming properties for ground reinforcement during liquid grouting and tunnel excavation. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have discovered that the above-mentioned problems can be solved by a rock consolidation grouting composition comprising a specific polyol component (A) containing an aqueous sodium silicate solution and a polyisocyanate component (B), and have thus completed the present invention.

[0010] That is, the present invention includes the following embodiments [1] to [6].

[0011] [1] A grout composition for rock consolidation comprising a polyol component (A) and a polyisocyanate component (B), wherein the polyol component (A) comprises an aqueous sodium silicate solution (A-1), an organic polyol (A-2) having 3 or more functional groups and a molecular weight of 200 or less, and a tertiary amine catalyst (A-3) having one active hydrogen, and the polyisocyanate component (B) comprises a mixture of diphenylmethane diisocyanate and polyphenyl polyphenylene polyisocyanate, and a reaction product of the mixture with a polyol.

[0012] [2] The grout composition for rock consolidation according to the above [1], wherein the organic polyol (A-2) having 3 or more functional groups and a molecular weight of 200 or less is glycerin.

[0013] [3] The grout composition for rock consolidation according to [1] or [2] above, characterized in that the tertiary amine catalyst (A-3) having one active hydrogen is contained in the polyol component (A) in an amount of 0.1 to 5 mass %.

[0014] [4] A grouting composition for rock consolidation according to any one of [1] to [3] above, characterized in that the solid content of the sodium silicate aqueous solution (A-1) is 30 to 50 mass % and the molar ratio of SiO2 / Na2O in the solid content is 2.0 to 3.0.

[0015] [5] A grouting composition for rock consolidation according to any one of [1] to [4] above, characterized in that the mass ratio of the polyol component (A) to the polyisocyanate component (B) is polyol component (A) / polyisocyanate component (B) = 100 / 50 to 100 / 150.

[0016] [6] A molded body obtained from the grouting composition for rock consolidation according to any one of [1] to [5] above. [Effects of the Invention]

[0017] The grouting composition for rock consolidation of the present invention provides stable workability and reactivity without being affected by moisture, even in environments where there is a lot of water leakage or spring water that occurs during tunnel excavation, and ensures resin strength by controlling foaming for ground reinforcement during chemical injection and tunnel excavation. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will now be described in further detail.

[0019] The grouting composition for rock consolidation in the present invention comprises a polyol component (A) (hereinafter also referred to simply as "component (A)") and a polyisocyanate component (B) (hereinafter also referred to simply as "component (B)").

[0020] First, the polyol component (A) will be described.

[0021] Component (A) in the present invention comprises an aqueous sodium silicate solution (A-1) (hereinafter also referred to as (A-1)), an organic polyol (A-2) (hereinafter also referred to as (A-2)) having three or more functional groups and a molecular weight of 200 or less, and a tertiary amine catalyst (A-3) (hereinafter also referred to as (A-3)) having one active hydrogen.

[0022] As the sodium silicate aqueous solution (A-1), commercially available sodium silicate aqueous solutions can be used. This sodium silicate is generally represented by the formula Na2O·xSiO2·nH2O. Here, x represents the molar ratio of SiO2 (silicon dioxide) to Na2O (sodium oxide), and in the present invention, it is preferably 2.0 to 3.0, more preferably 2.0 to 2.5, and most preferably 2.0 to 2.4. If x is less than 2.0, the curing properties may be poor when components (A) and (B) are mixed and cured. If x exceeds 3.0, the viscosity of the sodium silicate aqueous solution increases, which may impair the mixability with component (B) and may also reduce workability at low temperatures.

[0023] The solids content of (A-1) is preferably 30 to 50% by mass, more preferably 35 to 42% by mass, even more preferably 36 to 41% by mass, and most preferably 37 to 41% by mass. If the solids content of the sodium silicate aqueous solution is too high, it can be adjusted by diluting it with water. If the solids content is lower than 30% by mass, when components (A) and (B) are mixed and cured, the cured product may not be curable and the mechanical strength of the molded product may decrease. If the solids content exceeds 50% by mass, the viscosity of the sodium silicate aqueous solution increases, which may impair its mixability with component (B) and may also reduce workability at low temperatures.

[0024] In the present invention, the solid content of (A-1) refers to the proportion of all components other than water in (A-1).

[0025] Examples of organic polyols (A-2) having three or more functional groups and a molecular weight of 200 or less include aliphatic and alicyclic triols such as glycerin, butanetriol, pentanetriol, cyclopentanetriol, hexanetriol, cyclohexanetriol, heptanetriol, octanetriol, cyclooctanetriol, heptanetriol, nonanetriol, and decanetriol; aromatic triols such as trihydroxybenzene; ether-based triols; aliphatic tetraols such as erythritol, diglycerin, pentanetetraol, and hexanetetraol; and aromatic tetraols such as tetrahydroxybenzene, with glycerin being preferred. The number of functional groups in (A-2) of the present invention is three or more; if it is less than three, the injection solution will foam and sufficient resin strength will not be obtained. These may be used alone or in combination of two or more.

[0026] Furthermore, (A-2) has a molecular weight of 200 or less, preferably 180 or less, and more preferably 160 or less. If the molecular weight exceeds 200, the mechanical strength of the molded product after curing decreases. Furthermore, it is preferable that at least one of the OH groups in (A-2) is a primary OH group. If all of the OH groups in (A-2) are secondary or tertiary, the reaction with polyisocyanate will be slow, making it impossible to ensure curability and potentially causing leakage of the chemical solution components into water.

[0027] The tertiary amine catalyst (A-3) in the present invention has one active hydrogen in the molecule. Examples of functional groups having one active hydrogen include a hydroxy group and a secondary amino group. When the catalyst has two or more active hydrogens or a primary amino group, it acts as a crosslinking agent during the reaction with component (B), making it difficult to control the reactivity, which may result in filling defects due to clogging of the injection machine.

[0028] Examples of tertiary amines having a hydroxy group include N,N-dimethylethanolamine, N-methyl-N-(N',N'-dimethylaminoethyl)aminoethanol, N,N-dimethylethoxyethanol, 1,4-diazabicyclo[2.2.2]octane-2-methanol, 6-dimethylamino-1-hexanol, N',N-dimethylethoxy-N'-methyl-N'-ethylmethanol, N'',N''-dimethylamino-N'-methylethylamino-N-methyl-2-propanol, and bis(2-dimethylaminoethylamino)-2-propanol.

[0029] Examples of tertiary amines having a secondary amino group include N'-[2-(dimethylamino)ethyl]-N,N-dimethylethylenediamine, 3,3-iminobis(N,N-dimethyl-1-propanamine), N'-[2-(dimethylamino)methyl]-N,N-dimethylmethylenediamine, N,N,N',N'-tetraethyldiethylenetriamine, and 2-[2-(dimethylamino)ethoxy]-N-[2-[2-(dimethylamino)ethoxy]ethyl]-ethanamine.

[0030] Among these, N-methyl-N-(N',N'-dimethylaminoethyl)aminoethanol and N',N-dimethylethoxy-N'-methyl-N'-ethylmethanol are preferred from the viewpoint of reactivity and foaming properties.

[0031] In the present invention, the content of (A-3) in the polyol component (A) is preferably 0.1 to 5% by mass.

[0032] In the present invention, additives such as surfactants may be used to improve the dispersion stability of component (A) and the compatibility between component (A) and component (B). Examples of surfactants include anionic surfactants, cationic surfactants, and nonionic surfactants.

[0033] Examples of the anionic surfactant include alkyl carboxylates, alkyl sulfates, alkyl sulfonates, and alkyl phosphates.

[0034] Examples of cationic surfactants include ammonium salts such as benzalkonium chloride.

[0035] Examples of nonionic surfactants include glycerin fatty acid esters, alkyl polyethylene glycols, polyoxyethylene alkyl phenyl ethers, and alkyl glycosides.

[0036] These surfactants may be used alone or in combination.

[0037] In addition, antifoaming agents, diluents, antioxidants, reaction modifiers, etc. may be added to component (A) within the scope of the present invention.

[0038] Next, the polyisocyanate component (B) will be described.

[0039] Component (B) in the present invention is a reaction product of a mixture of diphenylmethane diisocyanate (hereinafter referred to as MDI) and polyphenylpolymethylene polyisocyanate (hereinafter referred to as polymeric MDI) with a polyol.

[0040] In the present invention, MDI includes various isomers of 4,4'-MDI, 2,4'-MDI, and 2,2'-MDI, and polymeric MDI refers to MDI to which one or more phenyl groups having an isocyanate group are further added via a methylene group.

[0041] The mass ratio of MDI to polymeric MDI is preferably MDI / polymeric MDI=20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30.

[0042] In the present invention, the prepolymer is preferably an isocyanate group-terminated prepolymer obtained by reacting a mixture of MDI and polymeric MDI with a polyol by a known method so that the equivalent ratio of isocyanate groups (hereinafter referred to as NCO groups) to OH groups (NCO groups / OH groups) is preferably in the range of 2 to 300, more preferably 5 to 100.

[0043] Examples of the polyol include organic diols such as butanediol, polyols such as the above-mentioned glycerin, trimethylolpropane, sorbitol, and sucrose, and polyether polyols obtained by adding alkylene oxides such as monoethanolamine, diethanolamine, triethanolamine, and ethylenediamine to these polyols.

[0044] Furthermore, a diluent for adjusting viscosity may be used in combination with component (B). Examples of diluents that have excellent compatibility with component (B), viscosity reducing properties, and mixing stability include alkylene carbonates such as propylene carbonate, and alkyl ethers such as propylene glycol monomethyl ether acetate and diethylene glycol monomethyl ether acetate. From the viewpoints of the working environment and safety, the amount of these added is preferably 1 to 5 mass% relative to component (B).

[0045] In the rock consolidation grout solution of the present invention, the blending ratio of component (A) to component (B) is preferably 50 to 150 parts by mass, more preferably 70 to 130 parts by mass, per 100 parts by mass of component (A). If the amount of component (B) is less than 50 parts by mass, urethane conversion may be insufficient, resulting in a lack of strength in the solidified product, while if it exceeds 150 parts by mass, the water may become cloudy or foam excessively during underwater curing.

[0046] The rock consolidation grout composition of the present invention overcomes the drawbacks of conventional inorganic-organic composite rock consolidation grout compositions. Specifically, the rock consolidation grout composition of the present invention has high compatibility between the polyol component (A) and the polyisocyanate component (B), making it possible to obtain uniform molded articles and to produce stable reinforced soil that is not affected by moisture even in environments where water leakage or spring water is frequent. [Example]

[0047] Examples of the present invention will be described in detail below, but the present invention is not limited to these examples. Unless otherwise specified, "%" in the examples is based on mass.

[0048] <Preparation of Polyisocyanate Component> <Preparation Example 1> A 1 L reactor equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube was charged with 952.0 g of Polyisocyanate 3 and 38.0 g of PPG-4000, and the temperature was raised to 80°C. While maintaining the temperature and mixing uniformly with a stirring blade, a urethane reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 50°C and 10.0 g of foam stabilizer was added to obtain Polyisocyanate Composition (S-2) (NCO content 30.2%, viscosity 110 mPa·s at 25°C).

[0049] <Preparation Example 2> A 1 L reactor equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube was charged with 972.0 g of Polyisocyanate 2 and 18.0 g of PPG-400, and the temperature was raised to 80°C. While maintaining the temperature and mixing uniformly with a stirring blade, a urethane reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 50°C, and 10.0 g of foam stabilizer and 50 g of propylene carbonate as a diluent were added to obtain Polyisocyanate Composition (S-3) (NCO content 28.6%, viscosity 160 mPa·s at 25°C).

[0050] [Table 1]

[0051] The ingredients in Table 1 are as follows: Polyisocyanate 1: Polymeric MDI (product name: MR-200, manufactured by Tosoh Corporation), MDI / Polymeric MDI = 39 / 61 (PA ratio), NCO content 31.1% Polyisocyanate 2: MDI / polymeric MDI = 68 / 32 (PA ratio), NCO content 32.9%, MDI (trade name: Millionate NM, manufactured by Tosoh Corporation) and polymeric MDI (trade name: MR-200, manufactured by Tosoh Corporation) mixed in a ratio of 21 / 79 (mass ratio) Polyisocyanate 3: MDI / polymeric MDI = 46 / 54 (PA ratio), NCO content 32.2%, MDI (trade name: Millionate NM, manufactured by Tosoh Corporation) and polymeric MDI (trade name: MR-200, manufactured by Tosoh Corporation) mixed in a ratio of 12 / 88 (mass ratio) PPG-4000: Polypropylene glycol, molecular weight 4000, functional group 2 (trade name: PP-4000, manufactured by Sanyo Chemical Industries, Ltd.) PPG-400: Polypropylene glycol, molecular weight 400, functional group number 2 (trade name: PP-400, manufactured by Sanyo Chemical Industries, Ltd.) Foam stabilizer: Siloxane-polyalkylene oxide copolymer (product name: NIAX SILICONE Y-16136, manufactured by MOMENTIVE) Diluent: Propylene carbonate (product name: Propylene Carbonate S, manufactured by BASF) The MDI / polymeric MDI ratio for Polyisocyanate 1, Polyisocyanate 2, and Polyisocyanate 3 is the peak area ratio (PA ratio) obtained by GPC measurement, and is expressed as (MDI monomer peak area) / (sum of peak areas of MDI oligomers other than MDI monomer).

[0052] The GPC measurement conditions are as follows: (1) Measuring instrument: HLC-8220 (manufactured by Tosoh Corporation) (2) Column: TSKgel (Tosoh Corporation) G3000H-XL G2500H-XL G2000H-XL G1000H-XL (3) Carrier: THF (tetrahydrofuran) (4) Detector: RI (refractive index) detector (5) Temperature: 40℃ (6)Flow rate: 1.000ml / min (7) Calibration curve: Standard polystyrene (manufactured by Tosoh Corporation) ·F-80 (molecular weight: 7.06×105, molecular weight distribution: 1.05) ·F-20 (molecular weight: 1.90×105, molecular weight distribution: 1.05) ·F-10 (molecular weight: 9.64×104, molecular weight distribution: 1.01) ·F-2 (molecular weight: 1.81×104, molecular weight distribution: 1.01) ·F-1 (molecular weight: 1.02×104, molecular weight distribution: 1.02) ·A-5000 (molecular weight: 5.97×103, molecular weight distribution: 1.02) ·A-2500 (molecular weight: 2.63×103, molecular weight distribution: 1.05) ·A-500 (molecular weight: 5.0×102, molecular weight distribution: 1.14) (8) Sample solution concentration: 0.5% THF solution.

[0053] [Table 2]

[0054] The ingredients in Table 2 are as follows: Sodium silicate aqueous solution 1: solid content 44.5%, molar ratio (SiO2 / Na2O) = 2.0 (product name: No. 1 sodium silicate K0, manufactured by Toso Sangyo Co., Ltd.) Sodium silicate aqueous solution 2: solid content 40.5%, molar ratio (SiO2 / Na2O) = 2.0 (product name: No. 1 sodium silicate O0, manufactured by Toso Sangyo Co., Ltd.) Sodium silicate aqueous solution 3: solid content 40.5%, molar ratio (SiO2 / Na2O) = 2.6 (trade name: No. 2 sodium silicate O6, manufactured by Toso Sangyo Co., Ltd.) 1,3-BG: 1,3-butanediol, molecular weight 90, functional group number 2 (trade name: 1,3-butanediol, manufactured by KH Neochem Co., Ltd.) Triethylene glycol: molecular weight 106, functional group number 2 (trade name: Triethylene glycol, manufactured by Mitsubishi Chemical Corporation) Glycerin: molecular weight 92, functional groups 3 (trade name: purified glycerin, manufactured by Sakamoto Pharmaceutical Co., Ltd.) Diglycerin: molecular weight 166, number of functional groups 4 (trade name: Diglycerin, manufactured by Sakamoto Pharmaceutical Co., Ltd.) Polyether 1: Polypropylene oxide, molecular weight 250, functional group number 3 (trade name: GP-250, manufactured by Sanyo Chemical Industries, Ltd.) Polyether 2: Polypropylene oxide, molecular weight 650, functional group number 3 (trade name: GP-600, manufactured by Sanyo Chemical Industries, Ltd.) Amine catalyst 1: N,N,N'-trimethyl-N'-hydroxyethyl bisaminoethyl ether (trade name: TOYOCAT RX10, manufactured by Tosoh Corporation) Amine catalyst 2: N-methyl-N-(N',N'-dimethylaminoethyl)aminoethanol (trade name: TOYOCAT RX5, manufactured by Tosoh Corporation) Amine catalyst 3: N,N,N',N'-tetramethylhexamethylenediamine (trade name: TOYOCAT MR, manufactured by Tosoh Corporation) Amine catalyst 4: triethylenediamine (trade name: TEDA L-33, manufactured by Tosoh Corporation).

[0055] <Method for evaluating reaction behavior> A foaming test was carried out using the polyol component (A) and polyisocyanate component (B) in the formulation shown in Table 3 (liquid temperature: 20°C, stirring conditions: 300 rpm x 10 seconds using a Three-One motor). The results are shown in Table 3.

[0056] [Table 3]

[0057] In the reactivity test, "free foaming" refers to blending the polyol component (A) and the polyisocyanate component (B) in a 1-L cup, mixing and stirring, and allowing the mixture to foam in the cup. "Foaming in water" refers to blending the polyol component (A) and the polyisocyanate component (B) in a 1-L cup, mixing and stirring, and then quickly pouring 100 ml of the blended liquid into another 1-L cup containing 500 ml of water, and vigorously stirring the water with a stirring rod for 30 seconds to allow the mixture to foam.

[0058] Cream time: The time (seconds) from the start of mixing and stirring the polyol component (A) and the polyisocyanate component (B) until the mixture becomes cloudy and creamy and the liquid surface rises.

[0059] Rise time: The time (seconds) from the start of mixing and stirring the polyol component (A) and the polyisocyanate component (B) until the compounded liquid foams and reaches its maximum height. However, when the foaming ratio is 1.0, this indicates the time it takes for the resin to lose its tack and harden. If the rise time in water is within 20 seconds of the rise time in free foaming, it can be said that the reactivity in water is good.

[0060] · Expansion ratio: The expansion ratio during free expansion is calculated using the following formula. Expansion ratio (times) = volume of foamed product (cm 3 ) / volume of the mixture before foaming (cm 3 ) A foaming ratio of 2.0 or less is considered to be good.

[0061] Water turbidity after foaming: In the underwater foaming test, the turbidity of the water was measured using a turbidity meter (TURBIDIMETER 2100N, manufactured by HACH) as an index of water contamination after the rise time had finished. A value of 20 or less is considered to be good.

[0062] Foaming after foaming: In the underwater foaming test, foaming of water is measured as an indicator of water contamination after the rise time has finished. 125 ml of the water used in the underwater foaming test after the rise time has finished is placed in a 250 ml polyethylene bottle, sealed, shaken vigorously for 10 seconds, and then left to stand. The time (seconds) until the foam disappears from the water surface is measured. A time of 60 seconds or less is considered good.

[0063] pH of water after foaming: The pH of the water used in the underwater foaming test is measured after the rise time has finished as an indicator of water contamination. The test is expressed as values ​​measured in 0.5 increments using pH test paper. A value of 9.5 or less is considered good.

[0064] Compression strength: Measured according to JIS K 7220 (compression test method for rigid foam plastics), with 10 MPa or more rated as A and less than 10 MPa rated as C. A rating of A indicates that the resin strength is sufficient when excavating.

Claims

1. A grouting composition for rock consolidation comprising a polyol component (A) and a polyisocyanate component (B), The polyol component (A) is Sodium silicate aqueous solution (A-1), an organic polyol (A-2) having 3 or more functional groups and a molecular weight of 200 or less, and Tertiary amine catalyst having one active hydrogen (A-3) Including, The polyisocyanate component (B) is comprising a mixture of diphenylmethane diisocyanate and polyphenyl polyphenylene polyisocyanate, and a reaction product of the mixture with a polyol; A grouting composition for rock consolidation, characterized by:

2. 2. The grouting composition for rock consolidation according to claim 1, wherein the organic polyol (A-2) having a functionality of 3 or more and a molecular weight of 200 or less is glycerin.

3. The tertiary amine catalyst (A-3) having one active hydrogen is contained in the polyol component (A) in an amount of 0.1 to 5% by mass. The grouting composition for rock consolidation according to claim 1 or 2.

4. The solid content of the aqueous sodium silicate solution (A-1) is 30 to 50 mass %, and SiO ２ / Na ２ 4. The grout composition for rock consolidation according to claim 1, wherein the molar ratio of O is 2.0 to 3.

0.

5. The grouting composition for rock consolidation according to any one of claims 1 to 4, characterized in that the mass ratio of the polyol component (A) to the polyisocyanate component (B) is polyol component (A) / polyisocyanate component (B) = 100 / 50 to 100 / 150.

6. A molded body obtained from the grout composition for rock consolidation according to any one of claims 1 to 5.

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