A shield synchronous grouting material suitable for water-rich karst strata

Abstract

The present invention discloses a shield synchronous grouting material suitable for water-rich karst strata, which belongs to the technical field of grouting fillers and is used to solve the technical problems that the grouting materials prepared in the prior art have poor fluidity and mechanical strength and are not suitable for shield construction; and the water-reducing agent used in the grouting material has low water-reducing efficiency. A shield synchronous grouting material suitable for water-rich karst strata includes cement, water, modified inorganic powder material, modified water-reducing agent, sulfate early strength agent and polypropylene fiber. Fly ash floating beads, light calcium carbonate and wollastonite are mixed and ground to micron level to obtain a mixture inorganic powder; the mixture inorganic powder is modified by a coupling agent, which can replace fine aggregate and improve the mechanical strength of the grouting material. An esterified monomer containing a long aliphatic chain, hydrolyzed maleic anhydride with multiple functional groups and sodium methyl propylene sulfonate are polymerized to prepare a modified water-reducing agent with high water-reducing efficiency and good dispersibility.

Description

Technical Field

[0001] The invention relates to the technical field of grouting fillers, and in particular to a shield synchronous grouting material suitable for water-rich karst strata. Background Art

[0002] During tunnel construction, shield tunneling has become the primary method due to its high efficiency, safety, reliability, and minimal impact on the natural environment. During shield tunneling, gaps form behind the tunnel segments and the ground, making synchronous grouting behind the tunnel walls essential for safe construction. Water-rich karst formations have high hard rock strength and high saturated uniaxial ultimate compressive strength. Shield tunneling synchronous grouting materials suitable for water-rich karst formations must possess high strength, high toughness, high impermeability, and long-term water resistance. Furthermore, improving the water-reducing efficiency of water-reducing agents and improving the dispersibility of grouting materials remain pressing technical challenges.

[0003] Patent application CN117567124A discloses a green, inorganic, tough TBM (Transportable Machine) backfill grouting material and its application. The TBM backfill grouting material includes cement, fly ash, desulfurized gypsum, bentonite, water-based polyurethane emulsion, and glass fiber. The addition of the water-based polyurethane emulsion improves the mechanical properties of the grouting material. However, compared to inorganic materials, organic polyesters have limited potential for improving the mechanical properties of the grouting material. Furthermore, the addition of modified glass fiber only further reduces the dispersion and water-reducing properties of the resulting grouting material components.

[0004] In view of the technical defects in this aspect, a solution is now proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a shield synchronous grouting material suitable for water-rich karst strata, which is used to solve the technical problems of poor mechanical properties, dispersibility and water-reducing properties of shield synchronous grouting materials suitable for water-rich karst strata in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A shield synchronous grouting material suitable for water-rich karst strata comprises the following components in parts by weight: 2000 parts of cement, 800 parts of water, 100-200 parts of modified inorganic powder material, 5-10 parts of modified water reducing agent, 5-10 parts of sulfate early strength agent and 1-2 parts of polypropylene fiber.

[0008] Furthermore, the preparation method of the modified inorganic powder material comprises the following steps:

[0009] S1. Fly ash beads, light calcium carbonate and wollastonite are mixed and added to a planetary ball mill for ball milling to obtain a mixed inorganic powder with a particle size of 30-40 μm;

[0010] S2. At -10°C, 10-20 g of tetramethylsilane is irradiated with ultraviolet light in a chlorine atmosphere to obtain polychloromethylsilane;

[0011] S3. Add mixed inorganic powder to the above polychloromethylsilane, mix and stir at -20°C for 1-2 hours to obtain modified inorganic powder.

[0012] Furthermore, in step S1, the usage ratio of fly ash beads, light calcium carbonate and wollastonite is 100-120g:10120g:200-210g.

[0013] Furthermore, in step S2, the frequency of ultraviolet light irradiation is 30-60 kW, and the ultraviolet light irradiation time is 30-60 min; in step S3, the amount of mixed inorganic powder is 200 g, and the mixing and stirring speed is 100-200 r / min.

[0014] Furthermore, the preparation method of the modified water-reducing agent comprises the following steps:

[0015] A1, polyethylene glycol monomethyl ether, acrylic acid, p-toluenesulfonic acid as a catalyst, and cyclohexane as a water-carrying agent are mixed evenly, and refluxed at 120-140° C. for 2-4 hours to obtain an esterified monomer;

[0016] A2, ammonium persulfate and deionized water are uniformly mixed to obtain an initiator solution; sodium methyl propylene sulfonate and maleic anhydride are added to the above-mentioned esterified monomer at room temperature to obtain a uniform monomer mixed solution; the initiator solution is then added dropwise to the monomer mixed solution. After the addition is complete, the mixture is kept at 110-120° C. for reaction for 4-6 hours, and then naturally cooled to room temperature to obtain a mixed solution; 0.1 mol / L NaOH solution is added dropwise to the mixed solution, and the pH value of the mixed solution is adjusted to 6-7 to obtain a modified water reducer solution.

[0017] Furthermore, in step A1, the ratio of polyethylene glycol monomethyl ether, acrylic acid, catalyst p-toluenesulfonic acid and water-carrying agent cyclohexane is 35-50g:10g:1-2g:1-5g; in step A2, the ratio of ammonium persulfate and deionized water is 5-10g:100mL; and the ratio of sodium methacrylate sulfonate and maleic anhydride is 30-40g:10-20g.

[0018] As another aspect of the present invention, a shield synchronous grouting material suitable for water-rich karst formations is prepared by the following steps:

[0019] B1. Take the raw materials of the formula by mass, add cement, water, polypropylene fiber and modified water reducer into a mixer in sequence, and stir at 100-200 r / min for 20-30 seconds to obtain a premix;

[0020] B2. Add modified inorganic powder material and sulfate early strength agent to the premix, stir at 500 r / min for 2-5 minutes, then pour into the mold, stir evenly, and cure for 28 days to obtain shield synchronous grouting material suitable for water-rich karst formations.

[0021] The present invention has the following beneficial effects:

[0022] 1. The shield synchronous grouting material suitable for water-rich karst strata prepared by the present invention comprises cement, modified inorganic powder material, sulfate early strength agent, polypropylene fiber and water; wherein, the modified inorganic powder material can replace the aggregate component to improve the mechanical properties and mechanical strength of the prepared grouting material; fly ash beads, light calcium carbonate and wollastonite are mixed and ground to micron level to obtain a mixed inorganic powder; wollastonite is a pyroxene-like mineral with a chain structure. It is a triclinic mineral of metamorphic origin, mostly produced in the form of needle-shaped, radial, and fibrous aggregates, and even microscopic The particles maintain a needle-like structure, resulting in high hardness and good chemical stability. Filling fly ash beads into grouting materials can improve the processing flowability of the grouting materials, increase the strength of the grouting materials, and also impart thermal insulation properties to the grouting materials. Chloromethylsilane, used as a coupling agent, can undergo a silane hydrolysis reaction with the hydroxyl groups on the surface of the mixed inorganic powder to prepare a modified inorganic powder, thereby improving the compatibility of the mixed inorganic powder in the cement matrix. Micron-level mixed inorganic powders can fill the tiny pores in cement, thereby improving the mechanical strength and mechanical properties of the prepared cement. Green inorganic tough backfill material has the advantages of high strength, high toughness, high impermeability, and long-term durability and water resistance. Inorganic powder materials have active and filling effects, generating a large number of hydration products, improving the interface structure within the grouting material, reducing porosity, and effectively enhancing the strength of the matrix. Inorganic early strength agents can form insoluble complex salts with a large amount of bound water in the matrix, increase the solid phase ratio, quickly generate calcium vanadium, and at the same time consume part of the cement hydration products, ultimately making the cement stone structure denser, thereby improving the strength of the cement. 2. The present invention pre-esterifies polyethylene glycol monomethyl ether with a long fatty chain and acrylic acid to obtain an esterified monomer containing an unsaturated double bond; the modified water-reducing agent with a long side chain has good initial fluidity, and the physical space hindrance generated by the long fatty chain side chain can prevent the cement particles from agglomerating and maintain dispersibility. Maleic anhydride is hydrolyzed to obtain an organic body with a double bond and a carboxyl group; under the action of ammonium persulfate initiator, the esterified monomer, maleic anhydride and sodium methyl propylene sulfonate undergo an addition polymerization reaction, thereby preparing a modified water-reducing agent containing functional groups such as carboxyl and sulfonic acid groups and a long aliphatic chain. The above-mentioned modified water-reducing agent has the advantages of high water-reducing efficiency, uniform dispersion in cement, and green environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0023] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] When preparing modified inorganic powders in Example 1-3, the fly ash beads used were purchased from Lingshou County Xuyang Mining Co., Ltd., the CAS number of light calcium carbonate is 71-34-1, and the CAS number of wollastonite is 13983-17-0; when preparing modified water-reducing agents in Example 4-6, the CAS number of polyethylene glycol monomethyl ether is 9004-74-4; when preparing shield synchronous grouting materials suitable for water-rich karst formations in Example 7-9, the cement used is ordinary Portland cement, model PO32.5, and the CAS number of polypropylene fiber is 9003-07-0.

[0025] Example 1

[0026] This embodiment provides a method for preparing a modified inorganic powder for use as a shield synchronous grouting material in water-rich karst formations, comprising the following steps:

[0027] S1. Mix 100 g of fly ash beads, 100 g of light calcium carbonate and 200 g of wollastonite (it is best to indicate the models of these three raw materials), add them to a planetary ball mill for ball milling, and grind to obtain a mixed inorganic powder with a particle size of 30 μm.

[0028] S2. Transfer the three-necked flask to an ice-water bath, adjust the temperature of the three-necked flask to -10°C, add 10 g of tetramethylsilane to the three-necked flask, then introduce chlorine gas into the three-necked flask to exclude air, and then irradiate the three-necked flask with ultraviolet light at a frequency of 30 kW and a duration of 30 min to obtain polychlorosilane.

[0029] S3. Then, 200 g of mixed inorganic powder was added to the three-necked flask, and the three-necked flask was placed in an ice bath. The mixture was stirred at -10°C and 100 r / min for 1 h to obtain modified inorganic powder.

[0030] Example 2

[0031] This embodiment provides a method for preparing a modified inorganic powder for use as a shield synchronous grouting material in water-rich karst formations, comprising the following steps:

[0032] S1. Mix 105 g of fly ash beads, 105 g of light calcium carbonate and 205 g of wollastonite, add them to a planetary ball mill and grind them to obtain a mixed inorganic powder with a particle size of 35 μm.

[0033] S2. Transfer the three-necked flask to an ice-water bath, adjust the temperature of the three-necked flask to -10°C, add 15 g of tetramethylsilane to the three-necked flask, then introduce chlorine gas into the three-necked flask to exclude air, and then irradiate the three-necked flask with ultraviolet light at a frequency of 40 kW and a duration of 50 min to obtain polychlorosilane.

[0034] S3. Then, 200 g of mixed inorganic powder was added to the three-necked flask, and the three-necked flask was placed in an ice bath. The mixture was stirred at -10°C and 150 r / min for 1.3 h to obtain modified inorganic powder.

[0035] Example 3

[0036] This embodiment provides a method for preparing a modified inorganic powder for use as a shield synchronous grouting material in water-rich karst formations, comprising the following steps:

[0037] S1. Mix 110 g of fly ash beads, 110 g of light calcium carbonate and 210 g of wollastonite, add the mixture into a planetary ball mill and perform ball milling to obtain a mixed inorganic powder with a particle size of 40 μm.

[0038] S2. Transfer the three-necked flask to an ice-water bath, adjust the temperature of the three-necked flask to -10°C, add 20 g of tetramethylsilane to the three-necked flask, then introduce chlorine gas into the three-necked flask to exclude air, and then irradiate the three-necked flask with ultraviolet light at a frequency of 60 kW and a duration of 30-60 min to obtain polychlorosilane.

[0039] S3. Then, 200 g of mixed inorganic powder was added to the three-necked flask, and the three-necked flask was placed in an ice bath. The mixture was stirred at -10°C and 200 r / min for 2 h to obtain modified inorganic powder.

[0040] Example 4

[0041] This embodiment provides a method for preparing a modified water-reducing agent for use as a shield synchronous grouting material in a water-rich karst stratum, comprising the following steps:

[0042] B1. A 500 mL reactor equipped with a thermometer, a stirring device, a titration device, and an oil-water separator was added to the reactor. 35 g of polyethylene glycol monomethyl ether was added, followed by evenly mixing 10 g of acrylic acid, 1 g of catalyst p-toluenesulfonic acid, and 1 g of water-carrying agent cyclohexane. The reactor was then heated to 120° C. and esterification was carried out under reflux for 2 h to prepare an esterified monomer.

[0043] B2, 5g of ammonium persulfate and 100ml of deionized water were mixed evenly to obtain an initiator solution; the outlet at the bottom of the oil-water separator in the reactor received the water generated by the esterification reaction, and then the reactor was cooled to room temperature. 100mL of deionized water, 30g of sodium methyl propylene sulfonate, and 10g of maleic anhydride were added to the reactor, and the mixture was mixed and stirred evenly to obtain a uniform monomer mixture; all the initiator solution was then added dropwise to the reactor. After the addition was completed, the mixture was kept warm at 110°C for 4h and then naturally cooled to room temperature to obtain a mixed solution; 0.1mol / L NaOH solution was added dropwise to the mixed solution, and the pH value of the mixed solution was adjusted to 6 to obtain a modified water reducer solution.

[0044] Example 5

[0045] This embodiment provides a method for preparing a modified water-reducing agent for use as a shield synchronous grouting material in a water-rich karst stratum, comprising the following steps:

[0046] B1. A 500 mL reactor equipped with a thermometer, a stirring device, a titration device, and an oil-water separator was added to the reactor. 45 g of polyethylene glycol monomethyl ether was added to the reactor, followed by evenly mixing 10 g of acrylic acid, 2 g of catalyst p-toluenesulfonic acid, and 3 g of water-carrying agent cyclohexane. The reactor was then heated to 130° C. and an esterification reaction was carried out under reflux for 3 h to prepare an esterified monomer.

[0047] B2, 6g of ammonium persulfate and 100ml of deionized water were mixed evenly to obtain an initiator solution; the outlet at the bottom of the oil-water separator in the reactor received the water generated by the esterification reaction, and then the reactor was cooled to room temperature. 100mL of deionized water, 35g of sodium methyl propylene sulfonate, and 15g of maleic anhydride were added to the reactor, and the mixture was mixed and stirred evenly to obtain a uniform monomer mixture; all the initiator solution was then added dropwise to the reactor. After the addition was completed, the mixture was kept warm at 115°C for 5h and then naturally cooled to room temperature to obtain a mixed solution; 0.1mol / L NaOH solution was added dropwise to the mixed solution, and the pH value of the mixed solution was adjusted to 7 to obtain a modified water reducer solution.

[0048] Example 6

[0049] This embodiment provides a method for preparing a modified water-reducing agent for use as a shield synchronous grouting material in a water-rich karst stratum, comprising the following steps:

[0050] B1. A 500 mL reactor equipped with a thermometer, a stirring device, a titration device, and an oil-water separator was added to the reactor. 50 g of polyethylene glycol monomethyl ether was added, followed by evenly mixing 10 g of acrylic acid, 2 g of catalyst p-toluenesulfonic acid, and 5 g of water-carrying agent cyclohexane. The reactor was then heated to 140° C. and esterification was carried out under reflux for 4 h to prepare an esterified monomer.

[0051] B. 10g of ammonium persulfate and 100ml of deionized water were mixed evenly to obtain an initiator solution; the outlet at the bottom of the oil-water separator in the reactor received water generated by the esterification reaction, and then the reactor was cooled to room temperature. 100mL of deionized water, 40g of sodium methyl propylene sulfonate, and 20g of maleic anhydride were added to the reactor, and the mixture was mixed and stirred evenly to obtain a uniform monomer mixed solution; all the initiator solution was then added dropwise to the reactor. After the addition was completed, the mixture was kept warm at 120°C for 6h, and then naturally cooled to room temperature to obtain a mixed solution; 0.1mol / L NaOH solution was added dropwise to the mixed solution, and the pH value of the mixed solution was adjusted to 7 to obtain a modified water reducer solution.

[0052] Example 7

[0053] This embodiment provides a method for preparing a shield synchronous grouting material suitable for water-rich karst formations, comprising the following steps:

[0054] According to weight parts, 2000 parts of cement, 800 parts of water, 1 part of polypropylene fiber and 5 parts of modified water-reducing agent were added to a mixer in sequence, and stirred at 100 r / min for 20 seconds. Then, 100 parts of modified inorganic powder material and 5 parts of sodium sulfate were added, and the mixture was mixed and stirred at 500 r / min for 2 minutes to obtain a grouting material. The grouting material was poured into a mold, stirred evenly, and cured for 28 days to obtain a shield synchronous grouting material suitable for water-rich karst strata.

[0055] Example 8

[0056] This embodiment provides a method for preparing a shield synchronous grouting material suitable for water-rich karst formations, comprising the following steps:

[0057] According to weight parts, 2000 parts of cement, 800 parts of water, 2 parts of polypropylene fiber and 6 parts of modified water-reducing agent are added to a mixer in sequence and stirred for 25 seconds. Then, 150 parts of modified inorganic powder material and 6 parts of potassium sulfate are added and stirred for 3 minutes to obtain a grouting material. The grouting material is poured into a mold, stirred evenly, and cured for 28 days to obtain a shield synchronous grouting material suitable for water-rich karst strata.

[0058] Example 9

[0059] This embodiment provides a method for preparing a shield synchronous grouting material suitable for water-rich karst formations, comprising the following steps:

[0060] According to weight parts, 2000 parts of cement, 800 parts of water, 2 parts of polypropylene fiber and 10 parts of modified water-reducing agent are added to a mixer in sequence and stirred for 30 seconds. Then, 200 parts of modified inorganic powder material and 10 parts of calcium sulfate are added and stirred for 5 minutes to obtain a grouting material. The grouting material is poured into a mold, stirred evenly, and cured for 28 days to obtain a shield synchronous grouting material suitable for water-rich karst strata.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 9 is that the modified inorganic powder is not added, and the modified inorganic powder is replaced by polypropylene fiber of the same mass.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 9 is that no esterified monomer was added when preparing the modified water-reducing agent.

[0065] Comparative Example 3

[0066] The difference between this comparative example and Example 9 is that maleic anhydride was not added when preparing the modified water-reducing agent.

[0067] Performance testing:

[0068] 1. According to JGJ / T70-2009 "Test Method for Basic Properties of Building Mortar", the 28-day compressive strength of the shield synchronous grouting material suitable for water-rich karst formations prepared in Examples 7-9 was tested; wherein, the size of the specimen used for the compressive strength test was 70 mm × 70 mm × 70 mm.

[0069] 2. According to JGJ / T70-2009 "Test Method for Basic Properties of Building Mortar", the consistency of the shield synchronous grouting materials suitable for water-rich karst formations prepared in Examples 7-9 was tested.

[0070] 3. The water separation rate and stone formation rate of the shield synchronous grouting materials suitable for water-rich karst formations prepared in Examples 7-9 were measured using the graduated cylinder method. Specific test results are shown in Table 1.

[0071] Table 1. Performance test data of the samples.

[0072]

[0073] Analyzing the data in Table 1, the shield synchronous grouting materials suitable for water-rich karst formations prepared in Examples 7-9 of the present invention have excellent mechanical properties, as shown by excellent 28d compressive strength values. However, in Comparative Example 1, the modified inorganic powder material of equal mass is replaced with polypropylene fiber, and the mechanical properties of the grouting material prepared by the present invention decrease, indicating that the modified inorganic powder material has excellent mechanical properties and strength.

[0074] The shield synchronous grouting materials suitable for water-rich karst formations prepared in Examples 7-9 of the present invention have good fluidity and moderate consistency; however, when preparing the grouting material, no esterified monomer was added when preparing the modified water-reducing agent in Comparative Example 2; when preparing the modified water-reducing agent in Comparative Example 3, no maleic anhydride was added, resulting in poor water-reducing efficiency of the prepared water-reducing agent; accordingly, the prepared grouting material has poor dispersibility, which is manifested as poor consistency, decreased water separation rate and stone formation rate. The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above embodiments, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the raw materials of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims

1. A shield synchronous grouting material suitable for water-rich karst strata, characterized in that: The invention comprises the following components in parts by weight: 2000 parts of cement, 800 parts of water, 100-200 parts of modified inorganic powder material, 5-10 parts of modified water reducing agent, 5-10 parts of sulfate early strength agent and 1-2 parts of polypropylene fiber; The preparation method of the modified inorganic powder material comprises the following steps: S1. Fly ash beads, light calcium carbonate and wollastonite are mixed and added to a planetary ball mill for ball milling to obtain a mixed inorganic powder with a particle size of 30-40 μm; S2. At -10°C, tetramethylsilane is irradiated with ultraviolet light in a chlorine atmosphere to obtain polychloromethylsilane; S3. Add mixed inorganic powder to the above polychloromethylsilane, mix and stir at -20°C for 1-2 hours to obtain modified inorganic powder.

2. The shield synchronous grouting material suitable for water-rich karst strata according to claim 1, characterized in that: In step S1, the usage ratio of fly ash floating beads, light calcium carbonate and wollastonite is 100-120g:100-120g:200-210g.

3. The shield synchronous grouting material suitable for water-rich karst strata according to claim 1, characterized in that: In step S2, the frequency of ultraviolet light irradiation is 30-60 kW, and the ultraviolet light irradiation time is 30-60 min; in step S3, the amount of mixed inorganic powder is 200 g, and the mixing and stirring speed is 100-200 r / min.

4. The shield synchronous grouting material suitable for water-rich karst strata according to claim 1, characterized in that: The preparation method of the modified water-reducing agent comprises the following steps: A1, polyethylene glycol monomethyl ether, acrylic acid, p-toluenesulfonic acid as a catalyst, and cyclohexane as a water-carrying agent are mixed evenly, and refluxed at 120-140° C. for 2-4 hours to obtain an esterified monomer; A2, ammonium persulfate and deionized water are uniformly mixed to obtain an initiator solution; sodium methyl propylene sulfonate and maleic anhydride are added to the above-mentioned esterified monomer at room temperature to obtain a uniform monomer mixture; the initiator solution is then added dropwise to the monomer mixture. After the addition is complete, the mixture is kept at 110-120° C. for reaction for 4-6 hours, and then naturally cooled to room temperature to obtain a mixed solution; 0.1 mol / L NaOH solution is added dropwise to the mixed solution, and the pH value of the mixed solution is adjusted to 6-7 to obtain a modified water reducer.

5. The shield synchronous grouting material suitable for water-rich karst strata according to claim 4, characterized in that: In step A1, the ratio of polyethylene glycol monomethyl ether, acrylic acid, catalyst p-toluenesulfonic acid and water-carrying agent cyclohexane is 35-50g:10g:1-2g:1-5g; in step A2, the ratio of ammonium persulfate and deionized water is 5-10g:100mL; and the ratio of sodium methacrylate sulfonate and maleic anhydride is 30-40g:10-20g.

6. A method for preparing shield synchronous grouting material suitable for water-rich karst strata according to claim 1, characterized in that: The following steps are involved: B1. Take the raw materials of the formula by mass, add cement, water, polypropylene fiber and modified water reducer into a mixer in sequence, and stir at 100-200 r / min for 20-30 seconds to obtain a premix; B2. Add modified inorganic powder material and sulfate early strength agent to the premix, stir at 500 r / min for 2-5 minutes, then pour into the mold, stir evenly, and cure for 28 days to obtain shield synchronous grouting material suitable for water-rich karst formations.

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