Full-life-cycle seepage-proofing and leakage-stopping multifunctional coating for subway tunnel and use method thereof

Abstract

The invention provides a full-life-cycle seepage-proofing and leakage-stopping multifunctional coating for a subway tunnel and a use method of the coating, and relates to the field of waterproof coatings. Comprising the following raw materials: 50-60 parts of cement, 10-15 parts of a polyurethane prepolymer, 5-10 parts of modified polyacrylic resin, 5-10 parts of modified vermiculite, 0.1-0.5 part of a cross-linking agent, 1-5 parts of a coagulant, 1-5 parts of glass fibers and 1-2 parts of magnesium stearate. The use method comprises the following steps: mixing the modified polyacrylic resin, part of cement and water, and stirring to obtain a premixed material; carrying out ball milling and dry mixing on the remaining raw materials to obtain a dry mixture; s2, adding the premixed material obtained in the step S1, the dry mixed material obtained in the step S2 and water into a sand mill, and performing sand milling and pulping to obtain slurry; and adding the slurry into a spraying machine, spraying the slurry to the surface of the leakage area, and maintaining until the slurry is cured. The coating has excellent waterproof and leaking stoppage effects and high compressive strength.

Description

Technical Field

[0001] This invention relates to the field of waterproof coatings, and more specifically, to a multifunctional, life-cycle anti-seepage and leak-stopping coating for subway tunnels and its application method. Background Technology

[0002] Subway tunnel waterproofing follows the principles of "prevention first, combining rigid and flexible materials, multiple layers of protection, and comprehensive management." Prevention first: The main waterproofing line relies on the self-waterproofing of tunnel segments and elastic sealing gaskets (such as EPDM) at joints. Combining rigid and flexible materials: Rigid waterproofing refers to the self-waterproofing of the concrete structure; flexible waterproofing refers to flexible materials such as coatings and membranes to compensate for concrete defects. Multiple layers of protection: In addition to the main waterproofing line, a second layer of protection (such as a waterproof coating) is installed on the inner wall of the tunnel. Comprehensive management: Various materials and technologies are combined to address different leakage situations (points, joints, surfaces).

[0003] Waterproof coatings can be used extensively in subway tunnels for waterproofing, and also for sealing leaks and cracks. Classified by raw material type, waterproof coatings include polyurea elastomer waterproof coatings, polymer cement waterproof coatings, and cement-based penetrating crystalline waterproof materials. Polyurea elastomer waterproof coatings cure quickly, producing a continuous, dense, and seamless coating with extremely high tensile strength and toughness, and are corrosion-resistant and aging-resistant. Polymer cement waterproof coatings have good adhesion, can be applied to damp surfaces, and are environmentally friendly. They offer high cost-effectiveness, are relatively easy to apply (by brushing or spraying), and bond firmly to concrete surfaces. Cement-based penetrating crystalline waterproof materials contain active chemical substances that penetrate the concrete, forming water-insoluble crystals that block capillary pores, thus giving the concrete itself waterproof properties and the ability to self-repair micro-cracks, making them suitable for waterproofing the back side of the concrete.

[0004] Patent CN109385124A discloses a multifunctional coating for tunnels. By compounding raw materials such as silicone-acrylic emulsion, lithium silicate, glycidyl methacrylate, polyvinyl alcohol, talc, kaolinite, vermiculite, and mica powder, the coating can fully integrate the various raw material components, thereby leveraging their synergistic effects to enhance and complement performance. This results in a multifunctional coating for tunnels with excellent fire resistance, adhesion, acid and alkali resistance, weather resistance, waterproofing, and antifungal and antibacterial properties; however, its waterproofing is relatively poor. Patent CN119463666A discloses a self-cleaning waterproof polymer coating for tunnels and its preparation method, comprising polyurethane resin, epoxy resin, fluorosilicone resin, titanium dioxide nanoparticles, zinc oxide nanoparticles, aluminum tripolyphosphate, silica nanoparticles, alumina micron-sized particles, graphene nanosheets, toughening agent, curing accelerator, and solvent. This coating achieves synergistic optimization of functions at each layer through a multi-layer composite structure: the bottom waterproof layer provides highly efficient waterproofing and weather resistance. While this waterproof coating achieves multi-functionality, it requires multiple applications, making the process cumbersome. Patent CN110117425A discloses a waterproof coating for tunnel repair engineering, comprising high-alumina cement powder, polypropylene fiber, polyacrylamide dimethyl silicone oil, styrene-butadiene rubber, epoxy resin, petroleum resin, asphalt, hydroxyl silicone oil, ethylene-vinyl acetate copolymer, turpentine, styrene-acrylic emulsion, and polyamide. This coating, specifically designed for tunnel repair, features high hardness, high waterproofness, and strong adhesion, improving construction quality and possessing significant potential for widespread application.

[0005] The aforementioned waterproof coatings for subway tunnels have multiple functions, but they also have drawbacks such as slow curing speed and long curing time. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-functional anti-seepage and leak-stopping coating for subway tunnels throughout its entire life cycle and its application method. This coating has good waterproof properties and high compressive strength, and is easy to apply.

[0007] The technical problem solved by this invention is achieved by the following technical solution.

[0008] On one hand, embodiments of the present invention provide a multi-functional anti-seepage and leak-stopping coating for subway tunnels throughout its entire life cycle, comprising the following raw materials:

[0009] 50-60 parts cement, 10-15 parts polyurethane prepolymer, 5-10 parts modified polyacrylic acid resin, 5-10 parts modified vermiculite, 0.1-0.5 parts crosslinking agent, 1-5 parts accelerator, 1-5 parts glass fiber, and 1-2 parts magnesium stearate.

[0010] In some embodiments of the present invention, the preparation method of the modified polyacrylic acid resin includes the following steps: plasma treatment of dried sodium polyacrylate resin particles to obtain activated resin; addition of the activated resin to an ethanol-water solution, stirring to obtain a suspension; addition of γ-methacryloxypropyltrimethoxysilane to the suspension, heating to 60-70°C, and dropwise addition of potassium persulfate solution under an inert atmosphere, stirring for 4-8 hours; cooling and filtering; placing the filtered resin particles into a Soxhlet extractor, using ethanol as a solvent, continuously extracting for 24-48 hours, and drying to obtain the modified polyacrylic acid resin. The amount of γ-methacryloxypropyltrimethoxysilane added is 5-10% of the mass of the sodium polyacrylate resin particles.

[0011] First, the dried resin is subjected to plasma treatment in an atmosphere of air, oxygen, or argon. This process etches peroxy groups (-OO-) or free radicals on the resin surface, which serve as active sites for subsequent grafting reactions. γ-Methacryloxypropyltrimethoxysilane (KH-570 monomer) possesses methacrylate double bonds suitable for polymerization and trimethoxysilane groups suitable for hydrolysis and condensation. Under the action of an initiator, the free radicals generated by the initiator decomposition attack the active sites on the resin surface, initiating the polymerization of KH-570 monomer and thus grafting silane molecules onto the resin surface. The silane molecular chains on the resin surface can form chemical bonds and strong hydrogen bonds with cement hydration products (such as CSH gel), significantly enhancing the interfacial adhesion between the resin and the cement matrix, reducing interfacial defects, and thus macroscopically improving compressive and flexural strength.

[0012] In some embodiments of the present invention, the preparation method of the modified vermiculite includes the following steps: calcining and expanding vermiculite at 850-1000℃, pulverizing, washing with dilute hydrochloric acid 2-3 times, and drying to obtain activated vermiculite; pulverizing diatomaceous earth and washing with dilute hydrochloric acid to obtain ultrafine diatomaceous earth; adding the activated vermiculite and the ultrafine diatomaceous earth to an ethanol aqueous solution containing a silane coupling agent and stirring at 60-70℃ for 2-3 hours; filtering, dry ball milling the filtered solid for 1-2 hours, and then drying at 100-120℃ for 1-2 hours to obtain the modified vermiculite.

[0013] In the ethanol-water solution, the mass ratio of the activated vermiculite to the ultrafine diatomaceous earth is 3:1-5:1, and the concentration of the silane coupling agent is 1-3 wt%. The silane coupling agent is KH-550 or KH-570.

[0014] The modified vermiculite provided by this invention uses vermiculite as a framework, with its large interlayer pores and expansibility providing the main water absorption channels and volume effect; and diatomaceous earth as a functional skin, with its huge specific surface area and nanoscale pores providing extremely strong surface adsorption and interfacial compatibility.

[0015] When vermiculite and diatomaceous earth are combined, they have a synergistic water absorption effect: vermiculite quickly absorbs a large amount of free water, while diatomaceous earth uses its micropores and surface adsorption to "lock in" the moisture and absorb the trace amounts of water vapor that are difficult to capture between vermiculite layers, thus creating a more thorough dry environment.

[0016] Enhanced strength: Diatomite nanoparticles fill the macroscopic pores of vermiculite, acting as "micron-nanoscale fillers" and significantly improving the mechanical strength and compressive strength of the composite particles.

[0017] Interface optimization: The surface of diatomaceous earth is rich in silanol groups, which can more effectively form a chemical bond with cement, greatly improving the dispersibility and interfacial adhesion of composite materials in coatings.

[0018] On the other hand, embodiments of the present invention provide a method for using a multi-functional anti-seepage and leak-stopping coating for subway tunnels throughout its entire life cycle, comprising the following steps:

[0019] S1, mix modified polyacrylic acid resin, some cement and water, stir to obtain premixed material;

[0020] S2, the remaining raw materials are ball-milled and dry-mixed to obtain a dry mixture;

[0021] S3, add the premixed material from step S1, the dry mixture from step S2, and water into a sand mill, and grind them into a slurry to obtain a slurry;

[0022] S4. Add the slurry to the spraying machine, spray it onto the surface of the leaking area, and cure it until the slurry is solidified.

[0023] In step S3, the solid content of the slurry is 70-90%. In step S1, the amount of cement added is 20-30% of the total cement content.

[0024] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0025] The coating provided by this invention uses cement as the main component, compounded with polyurethane prepolymer, modified polypropylene resin, modified vermiculite, and other raw materials, and exhibits excellent waterproofing and leak-stopping effects. Through chemical modification, silane functional groups are grafted onto the surface of the polyacrylic resin, enabling it to react with silicates in the cement, achieving a bridging effect. This significantly enhances the interfacial adhesion between the resin and the cement matrix, reduces interfacial defects, and thus macroscopically improves compressive and flexural strength. The multi-layered structure of the modified vermiculite has a certain degree of water absorption, and the diatomaceous earth embedded in the interlayer structure works synergistically to improve the coating's waterproofness. Specifically, vermiculite can quickly absorb large amounts of free water, while diatomaceous earth uses its micropores and surface adsorption to lock in moisture between layers and absorb trace amounts of water vapor that are difficult to capture between vermiculite layers, creating a more thoroughly dry environment. Furthermore, diatomaceous earth fills the macroscopic pores of vermiculite, acting as a "micron-nanoscale filler," significantly improving the coating's mechanical strength and compressive strength. The surface of diatomaceous earth is rich in silanol groups, which can more effectively form a chemical bond with the cement matrix, greatly improving the dispersibility and interfacial adhesion of vermiculite in coatings. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] Specifically, the sources of some of the raw materials in the embodiments and comparative examples are shown below.

[0028] Cement: ACZ ultrafine cement, Shandong Wenqu New Material Technology Co., Ltd.;

[0029] Sodium polyacrylate resin granules: Shandong Nuoer Biotechnology;

[0030] Vermiculite: Shijiazhuang Mayue Building Materials Co., Ltd.;

[0031] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0032] Example 1

[0033] 1. Prepare the ingredients according to the following proportions:

[0034] 60 parts cement, 15 parts polyurethane prepolymer, 10 parts modified polyacrylic acid resin, 10 parts modified vermiculite, 0.5 parts crosslinking agent (diisopropylbenzene peroxide), 5 parts accelerator (sodium aluminate), 5 parts glass fiber, and 2 parts magnesium stearate.

[0035] 2. Prepare modified polyacrylic acid resin according to the following method:

[0036] Dry sodium polyacrylate resin particles were subjected to plasma treatment to obtain activated resin. The parameters of the plasma treatment were: discharge voltage 3.6KV, treatment time 180s, working gas air, and gas flow rate 30L / min.

[0037] The activated resin was added to an ethanol-water solution (50 vol%), stirred, and nitrogen gas was bubbled into the solution to remove oxygen, resulting in a suspension. γ-methacryloxypropyltrimethoxysilane was added to the suspension, and the temperature was slowly raised to 60°C. Under an inert atmosphere, potassium persulfate solution was added dropwise, and the reaction was stirred for 8 hours. After cooling and filtration, the filtered resin particles were placed in a Soxhlet extractor and extracted continuously for 24 hours using ethanol as the solvent. The extracted particles were then dried to obtain the modified polyacrylic acid resin. The amount of γ-methacryloxypropyltrimethoxysilane added was 10% of the mass of the sodium polyacrylate resin particles. The mass fraction of the potassium persulfate solution was 1%, and the volume added was 5% of the suspension volume.

[0038] 3. Prepare modified vermiculite as follows:

[0039] Vermiculite was calcined and expanded at 1000℃, pulverized, washed three times with dilute hydrochloric acid (5%), and dried to obtain activated vermiculite. Diatomaceous earth was pulverized and washed twice with dilute hydrochloric acid to obtain ultrafine diatomaceous earth. The activated vermiculite and ultrafine diatomaceous earth were added to an ethanol-water solution containing a silane coupling agent (KH-550) and stirred at 70℃ for 2 hours. The mixture was filtered, and the filtered solid was dry-ball-milled for 2 hours, followed by drying at 100℃ for 2 hours to obtain the modified vermiculite. The mass ratio of the activated vermiculite to the ultrafine diatomaceous earth was 5:1, and the concentration of the silane coupling agent in the ethanol-water solution was 3 wt%.

[0040] 4. Prepare polyurethane prepolymers as follows:

[0041] Under an inert atmosphere, polyoxypropylene diol N220, MDI-50 and phosphoric acid (0.1% by weight of the diol) were added to the reactor in a weight ratio of 6:1. The reaction was carried out at 80°C for 4 hours, followed by degassing for 1 hour and cooling to obtain polyurethane prepolymer.

[0042] 5. The coating of this embodiment is prepared according to the following method:

[0043] S1, mix modified polyacrylic acid resin, 20% cement and water, stir to obtain premixed material;

[0044] S2, the remaining raw materials are ball-milled and dry-mixed for 10 minutes to obtain a dry mixture;

[0045] S3. Add the premixed material from step S1, the dry mixture from step S2, and water into a sand mill and mill for 30 minutes to make a slurry. By adjusting the amount of water added, control the solid content of the slurry to be 70-90%.

[0046] S4. Add the slurry to the spraying machine, spray it onto the surface of the leaking area, and cure it until the slurry is solidified.

[0047] Example 2

[0048] The difference from Example 1 is that the raw materials are prepared according to the following proportions:

[0049] 50 parts cement, 10 parts polyurethane prepolymer, 5 parts modified polyacrylic acid resin, 5 parts modified vermiculite, 0.1 parts crosslinking agent, 1 part accelerator, 1 part glass fiber, and 1 part magnesium stearate.

[0050] The remaining raw materials, preparation methods, and usage methods are the same as in Example 1.

[0051] Example 3

[0052] The difference from Example 1 is that the raw materials are prepared according to the following proportions:

[0053] 55 parts cement, 12 parts polyurethane prepolymer, 8 parts modified polyacrylic acid resin, 8 parts modified vermiculite, 0.3 parts crosslinking agent, 3 parts accelerator, 3 parts glass fiber, and 1.5 parts magnesium stearate.

[0054] The remaining raw materials, preparation methods, and usage methods are the same as in Example 1.

[0055] Example 4

[0056] The difference from Example 1 is that the raw materials are prepared according to the following proportions:

[0057] 50 parts cement, 15 parts polyurethane prepolymer, 10 parts modified polyacrylic acid resin, 5 parts modified vermiculite, 0.3 parts crosslinking agent, 3 parts accelerator, 3 parts glass fiber, and 1 part magnesium stearate.

[0058] The remaining raw materials, preparation methods, and usage methods are the same as in Example 1.

[0059] Example 5

[0060] The difference from Example 1 is that the modified polyacrylic acid resin was prepared according to the following method:

[0061] Dry sodium polyacrylate resin particles were subjected to plasma treatment to obtain activated resin. The parameters of the plasma treatment were: discharge voltage 3.6KV, treatment time 180s, working gas air, and gas flow rate 30L / min.

[0062] The activated resin was added to an ethanol-water solution (50 vol%), stirred, and nitrogen gas was bubbled into the solution to remove oxygen, resulting in a suspension. γ-methacryloxypropyltrimethoxysilane was added to the suspension, and the temperature was slowly raised to 70°C. Under an inert atmosphere, potassium persulfate solution was added dropwise, and the reaction was stirred for 4 hours. After cooling and filtration, the filtered resin particles were placed in a Soxhlet extractor and extracted continuously for 30 hours using ethanol as the solvent. The extracted particles were then dried to obtain the modified polyacrylic acid resin. The amount of γ-methacryloxypropyltrimethoxysilane added was 5% of the mass of the sodium polyacrylate resin particles. The mass fraction of the potassium persulfate solution was 1%, and the volume added was 5% of the suspension volume.

[0063] The remaining raw materials, preparation methods, and usage methods are the same as in Example 1.

[0064] Example 6

[0065] The difference from Example 1 is that the modified polyacrylic acid resin was prepared according to the following method:

[0066] Dry sodium polyacrylate resin particles were subjected to plasma treatment to obtain activated resin. The parameters of the plasma treatment were: discharge voltage 3.6KV, treatment time 180s, working gas air, and gas flow rate 30L / min.

[0067] The activated resin was added to an ethanol-water solution (50 vol%), stirred, and nitrogen gas was bubbled into the solution to remove oxygen, resulting in a suspension. γ-methacryloxypropyltrimethoxysilane was added to the suspension, and the temperature was slowly raised to 65°C. Under an inert atmosphere, potassium persulfate solution was added dropwise, and the reaction was stirred for 6 hours. After cooling and filtration, the filtered resin particles were placed in a Soxhlet extractor and continuously extracted for 48 hours using ethanol as the solvent. The extracted particles were then dried to obtain the modified polyacrylic acid resin. The amount of γ-methacryloxypropyltrimethoxysilane added was 8% of the mass of the sodium polyacrylate resin particles. The mass fraction of the potassium persulfate solution was 1%, and the volume added was 5% of the suspension volume.

[0068] The remaining raw materials, preparation methods, and usage methods are the same as in Example 1.

[0069] Example 7

[0070] The difference from Example 1 is that the modified vermiculite was prepared according to the following method:

[0071] Vermiculite was calcined and expanded at 900°C, pulverized, washed three times with dilute hydrochloric acid (5%), and dried to obtain activated vermiculite. Diatomaceous earth was pulverized and washed twice with dilute hydrochloric acid to obtain ultrafine diatomaceous earth. The activated vermiculite and ultrafine diatomaceous earth were added to an ethanol-water solution containing a silane coupling agent (KH-570) and stirred at 60°C for 3 hours. After filtration, the filtered solid was dry-ball-milled for 1-2 hours and then dried at 120°C for 1 hour to obtain the modified vermiculite. The mass ratio of the activated vermiculite to the ultrafine diatomaceous earth was 3:1, and the concentration of the silane coupling agent in the ethanol-water solution was 1 wt%. The remaining raw materials, preparation methods, and usage methods were the same as in Example 1.

[0072] Example 8

[0073] The difference from Example 1 is that the modified vermiculite was prepared according to the following method:

[0074] Vermiculite was calcined and expanded at 850-1000℃, pulverized, washed twice with dilute hydrochloric acid (5%), and dried to obtain activated vermiculite. Diatomaceous earth was pulverized and washed twice with dilute hydrochloric acid to obtain ultrafine diatomaceous earth. The activated vermiculite and ultrafine diatomaceous earth were added to an ethanol-water solution containing a silane coupling agent (KH-570) and stirred at 60℃ for 2 hours. The mixture was filtered, and the filtered solid was dry-ball-milled for 2 hours, followed by drying at 100℃ for 2 hours to obtain the modified vermiculite. The mass ratio of the activated vermiculite to the ultrafine diatomaceous earth was 4:1, and the concentration of the silane coupling agent in the ethanol-water solution was 2 wt%.

[0075] The remaining raw materials, preparation methods, and usage methods are the same as in Example 1.

[0076] Comparative Example 1

[0077] The difference from Example 1 is that polyacrylic acid resin is used instead of the modified polyacrylic acid resin in Example 1, while the other raw materials, preparation methods and usage methods are the same as in Example 1.

[0078] Comparative Example 2

[0079] The difference from Example 1 is that vermiculite is used instead of the modified vermiculite in Example 1, while the other raw materials, preparation methods and usage methods are the same as in Example 1.

[0080] Comparative Example 3

[0081] The difference from Example 1 is that polyacrylic acid resin is used instead of the modified polyacrylic acid resin in Example 1, and vermiculite is used instead of the modified vermiculite in Example 1. All other raw materials, preparation methods and usage methods are the same as in Example 1.

[0082] Experimental Example

[0083] The coatings of Examples 1-8 and Comparative Examples 1-3 were tested in accordance with GB / T 16777-2008 and GB 45671-2025, and the results are shown in Table 1.

[0084] Specifically, the Vicat method was used to test the initial setting time and final setting time of the coating. The initial setting time was recorded when the needle penetrated the slurry to a depth of 4 mm ± 1 mm, and the final setting time was recorded when the needle penetration depth was ≤ 0.5 mm. Each group of coatings was tested 3 times and the average value was taken.

[0085] Table 1

[0086]

[0087]

[0088] As can be seen from Table 1, the coatings of Examples 1-8 have short initial setting time and final setting time, and good waterproof performance.

[0089] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A multi-functional, life-cycle seepage-proofing and leak-stopping coating for subway tunnels, characterized in that: By weight, it includes the following ingredients: 50-60 parts cement, 10-15 parts polyurethane prepolymer, 5-10 parts modified polyacrylic acid resin, 5-10 parts modified vermiculite, 0.1-0.5 parts crosslinking agent, 1-5 parts accelerator, 1-5 parts glass fiber, and 1-2 parts magnesium stearate.

2. The multi-functional anti-seepage and leak-stopping coating for subway tunnels according to claim 1, characterized in that, The preparation method of the modified polyacrylic acid resin includes the following steps: Dry sodium polyacrylate resin particles are subjected to plasma treatment to obtain activated resin; The activated resin was added to an ethanol-water solution and stirred to obtain a suspension. Add γ-methacryloxypropyltrimethoxysilane to the suspension, heat to 60-70℃, add potassium persulfate solution dropwise under an inert atmosphere, and stir the reaction for 4-8 hours. After cooling and filtration, the filtered resin particles are placed in a Soxhlet extractor and extracted continuously for 24-48 hours using ethanol as a solvent. After drying, the modified polyacrylic acid resin is obtained.

3. The multi-functional anti-seepage and leak-stopping coating for subway tunnels according to claim 2, characterized in that, The amount of γ-methacryloyloxypropyltrimethoxysilane added is 5-10% of the mass of sodium polyacrylate resin particles.

4. The multi-functional anti-seepage and leak-stopping coating for subway tunnels according to claim 1, characterized in that, The preparation method of the modified vermiculite includes the following steps: Vermiculite is calcined at 850-1000℃ to expand, pulverized, washed 2-3 times with dilute hydrochloric acid, and dried to obtain activated vermiculite. Diatomaceous earth is pulverized and washed with dilute hydrochloric acid to obtain ultrafine diatomaceous earth. The activated vermiculite and the ultrafine diatomaceous earth were added to an ethanol aqueous solution containing a silane coupling agent and stirred at 60-70°C for 2-3 hours. The solid was filtered and then dry-ball-milled for 1-2 hours, followed by drying at 100-120°C for 1-2 hours to obtain the modified vermiculite.

5. The multi-functional anti-seepage and leak-stopping coating for subway tunnels according to claim 4, characterized in that, In the ethanol-water solution, the mass ratio of the activated vermiculite to the ultrafine diatomaceous earth is 3:1-5:1, and the concentration of the silane coupling agent is 1-3 wt%.

6. The multi-functional anti-seepage and leak-stopping coating for subway tunnels according to claim 4, characterized in that, The silane coupling agent is KH-550 or KH-570.

7. A method of using a multi-functional, life-cycle seepage-proofing and leak-stopping coating for subway tunnels as described in any one of claims 1-6, characterized in that, Includes the following steps: S1, mix modified polyacrylic acid resin, some cement and water, stir to obtain premixed material; S2, the remaining raw materials are ball-milled and dry-mixed to obtain a dry mixture; S3, add the premixed material from step S1, the dry mixture from step S2, and water into a sand mill, and grind them into a slurry to obtain a slurry; S4. Add the slurry to the spraying machine, spray it onto the surface of the leaking area, and cure it until the slurry is solidified.

8. The method of using the multi-functional anti-seepage and leak-stopping coating for subway tunnels according to claim 7, characterized in that, In step S3, the solid content of the slurry is 70-90%.

9. The method of using the multi-functional anti-seepage and leak-stopping coating for subway tunnels according to claim 7, characterized in that, In step S1, the amount of cement added is 20-30% of the total cement volume.

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