A tunnel crack repair material containing a modified marine silt carrier and a method of preparation

Abstract

This invention belongs to the field of tunnel engineering materials technology, and specifically relates to a tunnel crack repair material containing modified marine silt carrier and its preparation method. The tunnel crack repair material prepared by this invention consists of ultrafine cement, anti-shrinkage self-healing components, polymer emulsion, anti-corrosion components, quick-setting stabilizer, high-efficiency water-reducing agent, penetration promoter, and water. It constructs an integrated repair system of "self-healing - anti-shrinkage - high adhesion - erosion resistance," realizing the resource utilization of marine silt solid waste. The material has a 7-day self-healing efficiency ≥90%, a retention rate ≥98% under 0.8 MPa flowing water pressure, a 28-day compressive strength ≥48 MPa, and an interfacial bonding strength ≥3.8 MPa. It can resist corrosive ion erosion and freeze-thaw cycles, and is suitable for waterproofing, reinforcement, and long-term repair of various cracks in underground engineering projects such as subway tunnels and highway tunnels under high groundwater levels and freeze-thaw cycles. It is not prone to re-cracking after repair and has strong construction adaptability.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering materials technology, and specifically relates to a tunnel crack repair material containing a modified marine silt carrier and its preparation method. Background Technology

[0002] When using cement-based materials to repair tunnel cracks in special geological environments (such as karst hydrogeological environments or high groundwater levels), the following challenges are often encountered: high groundwater levels and high water pressure, traditional grouting materials are easily washed away, making it difficult to effectively seal cracks; and the presence of SO4... 2- Cl - Corrosive ions can cause the restoration to become loose and peel off or the steel reinforcement to rust; when the temperature is below 0°C, repeated freezing and swelling due to water seepage can cause the restoration to crack, and there is a freeze-thaw cycle phenomenon.

[0003] Currently, tunnel crack repair mainly involves ordinary cement-based grouting materials, ultrafine cement grouting materials, and polymer-modified cement-based materials. However, when applied in environments with high groundwater levels, these materials have several drawbacks: weak erosion resistance, making them unable to effectively seal cracks; high brittleness and poor deformation resistance, leading to easy re-cracking after repair; high shrinkage rate, making them prone to self-cracks and debonding under wet-dry cycles; insufficient resistance to chemical corrosion and freeze-thaw cycles; and difficulty in penetrating to microcracks below 0.1 mm, thus failing to achieve comprehensive sealing.

[0004] Existing self-healing technologies mostly rely on special additives, which have problems such as complex construction and high cost, making them difficult to adapt to high water level repair scenarios. Moreover, existing traditional repair materials are prone to environmental pollution. Therefore, it is urgent to develop a cement-based composite material and supporting repair method that takes solid waste resource utilization as the core, takes into account erosion resistance, shrinkage resistance, corrosion resistance, high adhesion, strong permeability and self-healing functions, and is suitable for water-conducting construction environments. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a tunnel crack repair material containing a modified marine silt carrier and its preparation method. The cement-based composite material prepared by the present invention uses modified marine silt self-healing carrier particles as the core functional component. Specifically, the modified marine silt carrier is prepared through directional pore formation, vacuum saturation, and composite coating processes to achieve water storage and crack-triggered self-healing. In conjunction with ultrafine cement, polymer emulsion, and other components, an integrated repair system of "self-healing, anti-shrinkage, high adhesion, and erosion resistance" is constructed to adapt to the long-term repair of tunnel cracks in high groundwater environments, while simultaneously realizing the resource utilization of marine silt solid waste.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a tunnel crack repair material containing a modified marine silt carrier, comprising the following components by weight: 48-58 parts of ultrafine cement, 5-10 parts of anti-shrinkage self-healing component, 10-16 parts of polymer emulsion, 5-12 parts of anti-corrosion component, 3-7 parts of quick-setting stabilizer, 0.8-2.2 parts of high-efficiency water-reducing agent, 1-4 parts of penetration promoter, and 18-26 parts of water.

[0007] Preferably, the tunnel crack repair material comprises, by weight, the following components: 53 parts ultrafine cement, 8 parts anti-shrinkage self-healing component, 13 parts polymer emulsion, 8 parts anti-corrosion component, 5 parts quick-setting stabilizer, 1.5 parts high-efficiency water-reducing agent, 2 parts penetration promoter, and 22 parts water.

[0008] Preferably, the ultrafine cement is selected from one or more of silicate ultrafine cement, sulfoaluminate ultrafine cement, and ferroaluminate ultrafine cement, with a particle size of 5~10 μm and a specific surface area of ​​600~800 m² / kg, and is more preferably silicate ultrafine cement.

[0009] Preferably, the anti-shrinkage self-healing component is composed of ettringite-type expanding agent, sodium polyacrylate water-retaining agent and modified marine silt self-healing carrier particles in a mass ratio of 3~4:1:2~3; The modified marine silt self-healing carrier particles are etched, water-saturated particles with a cement-silica-nano silica composite shell on the surface.

[0010] More preferably, the etched water-saturated particles have a particle size of 40~80 μm and a water saturation rate of 35%~45%; the coating solution used for surface coating is prepared by ordinary silicate cement, silica fume, nano silica, polycarboxylate superplasticizer and water in a mass ratio of 150~170:25~35:5~8:1.5~2:70~90 to form a coating layer with a thickness of 2~5 μm.

[0011] Preferably, the polymer emulsion is an acrylate-styrene-butadiene rubber composite emulsion, wherein the mass ratio of acrylate to styrene-butadiene rubber in the composite emulsion is 3~5:1.

[0012] Preferably, the polymer emulsion has a solid content of 45% to 60%, a glass transition temperature (Tg) of -20 to 10°C, and a minimum film-forming temperature (MFT) of ≤5°C; more preferably, the glass transition temperature is -10 to 5°C and the minimum film-forming temperature is ≤3°C.

[0013] Preferably, the anti-corrosion component is composed of slag powder, silica fume, and rust inhibitor in a mass ratio of 4~5:2~3:1, wherein the slag powder has a particle size of 1~3 μm, the silica fume has a particle size of 0.1~0.5 μm, and the rust inhibitor is calcium nitrite or an amino alcohol rust inhibitor; more preferably, the mass ratio of slag powder, silica fume, and rust inhibitor is 4:2:1.

[0014] Preferably, the quick-setting stabilizer is a mixture of aluminate quick-setting agent and clay minerals in a mass ratio of 2 to 3:1.

[0015] More preferably, the clay minerals include bentonite and attapulgite.

[0016] Preferably, the high-efficiency water-reducing agent is a polycarboxylate-based high-efficiency water-reducing agent with a water reduction rate of ≥25%.

[0017] Preferably, the penetration enhancer is an organosilicon penetration enhancer, wherein the effective component (organosilicon) is 98%.

[0018] A second aspect of the present invention provides a method for preparing the above-mentioned tunnel crack repair material, comprising the following steps: After drying the marine silt, it is ground and sieved. The silt powder is mixed with a polyvinyl alcohol aqueous solution and granulated to obtain silt-based core particles. Then, the silt-based core particles are placed in a composite etching solution and stirred. After the reaction is completed, etched marine silt porous particles are obtained. Then, the etched marine silt porous particles were vacuumed to remove the air from the pores and water was introduced. The pressure was restored to normal and the particles were allowed to stand to fully absorb water and reach a supersaturated state. The saturated particles were then mixed with the coating liquid and stirred to obtain modified marine silt self-healing carrier particles. A shrinkage-resistant self-healing component is obtained by mixing ettringite-type expansive agent, sodium polyacrylate water-retaining agent, and modified marine silt self-healing carrier particles. Then, ultrafine cement, shrinkage-resistant self-healing component, corrosion-resistant component, quick-setting stabilizer, and high-efficiency water-reducing agent are mixed evenly to obtain a dry powder mixture. Then, a penetration promoter and water are added to the dry powder mixture, and after stirring, a polymer emulsion is added to obtain the final product.

[0019] Preferably, the drying temperature is 105~110℃, the grinding speed is 300~400 rpm, the grinding time is 30~45 min, and the particle size of the sieve is 500 mesh.

[0020] Preferably, the mass ratio of the sludge powder to the polyvinyl alcohol aqueous solution is 1:0.8~1.2; and the particle size of the sludge-based core particles is 35~75 μm.

[0021] Preferably, the composite etching solution is prepared by mixing a 1.5 M HCl solution and a 5% H2O2 solution; the solid-liquid ratio of the silt-based core particles to the composite etching solution is 1:5.

[0022] Preferably, after the silt-based core particles are mixed with the composite etching solution, they are stirred at a speed of 180-220 rpm for 45-60 min in a constant temperature water bath at 45-50℃. After the reaction is completed, the mixture is washed and dried at 70-90℃ for 10-15 h to obtain etched marine silt porous particles.

[0023] Preferably, the vacuuming pressure is below -0.09 MPa and is maintained for 30 minutes to expel pore air; the settling time is 36~48 hours to allow the particles to reach a supersaturated water content state.

[0024] Preferably, the stirring speed is 150~180 rpm and the stirring time is 120~150 s to ensure that a dense cement-silica-nano silica composite coating layer with a thickness of 2~5 μm is formed on the particle surface.

[0025] Preferably, the particles obtained after stirring are first air-dried in an environment with a relative humidity of 60%~70% for 20~30 hours, and finally passed through a 150-mesh sieve to obtain modified marine silt self-healing carrier particles.

[0026] Preferably, the stirring is first performed at 100-120 r / min for 2-3 min, then the polymer emulsion is added, and the speed is adjusted to 150-180 r / min and stirring is continued for 3-5 min, so that the viscosity of the slurry of the tunnel crack repair material is finally controlled to be 500-1500 mPa·s.

[0027] A third aspect of the present invention provides a method for repairing tunnel cracks using the material described in the first aspect, comprising the following steps: After the crack is pretreated, a V-shaped groove is chiseled along the direction of the crack extension. Then, the water is diverted according to the seepage flow rate. The grouting pressure is adjusted according to the crack width for grouting. After grouting, the V-shaped groove is filled and smoothed with the tunnel crack repair material described in the first aspect. Finally, the repair surface is subjected to adaptive curing.

[0028] Preferably, the crack pretreatment includes mechanical dust removal and chemical degreasing of the crack base surface to remove debris, laitance and loose concrete from the tunnel crack surface.

[0029] Preferably, after the V-groove is excavated, compressed air is used to remove the cracks and dust inside the V-groove, and organic solvent is used to clean the inner wall and the surface of the groove. Then, corresponding diversion measures are taken according to the water flow rate. More preferably, the organic solvent is selected from one or more of acetone, anhydrous ethanol, and isopropanol.

[0030] Preferably, the width of the V-groove is 5-10 mm and the depth is 3-8 mm.

[0031] Preferably, when the seepage flow rate is ≤0.5 mL / min, the flow is directly guided by a drainage pipe; if the seepage flow rate is >0.5 mL / min, 45° inclined drainage holes are drilled on both sides of the crack, and the drainage pipe is inserted after being staggered to control the seepage flow rate to ≤0.5 mL / min. The spacing between the drainage holes is 50~80 cm, the hole diameter is 12~16 mm, and the hole depth is 1.2~1.8 times the crack depth.

[0032] Preferably, microcracks with a crack width < 0.1 mm are treated with low-pressure permeation grouting at 0.1~0.3 MPa; fine cracks with a crack width of 0.1~2 mm are treated with medium-pressure grouting at 0.3~0.6 MPa; and medium-wide / wide cracks with a crack width ≥ 2 mm are treated with high-pressure grouting at 0.6~1.0 MPa.

[0033] Preferably, after the grouting is completed, the pressure is stabilized for 3 to 5 minutes to ensure that the cracks are filled tightly.

[0034] Preferably, the adaptive maintenance includes covering the repair surface with a moisturizing maintenance cloth to maintain humidity ≥90% and maintenance temperature 5~35℃; or during winter construction, applying a heat-insulating maintenance agent or building a heat-insulating shed to ensure that the temperature is not lower than 5℃.

[0035] Preferably, the adaptation curing time is no less than 14 days, with watering 2-3 times a day for the first 7 days. After curing, the filling density is tested, a water pressure test is conducted, and a pull-out test is used to test the interface bonding strength. If the test fails, the part is removed and repaired. The water pressure test is conducted at 1.2-1.5 times the groundwater pressure, i.e., no leakage is considered acceptable after 30 minutes of constant pressure. The interface bonding strength is considered acceptable in the pull-out test if it is ≥3.5 MPa.

[0036] A fourth aspect of the present invention provides the application of the tunnel crack repair material described in the first aspect and / or the repair method described in the third aspect in a high groundwater level environment.

[0037] Preferably, the high groundwater level environment includes subway tunnels, highway tunnels, water conservancy tunnels, underground integrated pipe corridors, and hydraulic dam corridors.

[0038] The beneficial effects achieved by one or more technical solutions of the present invention are as follows: (1) Solid waste resource utilization, environmental and economic benefits: This invention uses marine silt to prepare self-healing carrier particles to solve the problem of solid waste disposal; the carrier particles have a water saturation rate of 35%~45% and excellent water storage performance. Their active minerals enhance the strength of the repair body and form a chemical anchor with the polymer emulsion to improve the stability of the repair.

[0039] (2) Self-healing and anti-shrinkage synergy to reduce the risk of cracking again: The anti-shrinkage self-healing component involved in this invention compensates for hydration and drying shrinkage, with a drying shrinkage rate ≤0.025%; the carrier particles trigger water release from cracks, stimulating secondary hydration to fill cracks, with a self-healing efficiency ≥90% in 7 days, significantly reducing the probability of cracking again in the repair body.

[0040] (3) Suitable for construction with water level and erosion resistance and high adhesion: The quick-setting stabilizer involved in this invention accelerates the setting, and the material retention rate is ≥98% under 0.8MPa flowing water pressure, avoiding slurry loss; the polymer emulsion improves the toughness and interfacial adhesion of the material, and the interfacial adhesion strength is ≥3.8 MPa after 28 days. The elastic modulus matches the lining concrete and adapts to the deformation of the base.

[0041] (4) Excellent overall performance and suitable for complex service environment: The components in this invention work together to achieve a 28-day compressive strength of ≥48 MPa, excellent resistance to freeze-thaw and corrosion, and low strength loss rate after freeze-thaw cycles; the penetration promoter can achieve penetration and sealing of microcracks below 0.1mm, resist corrosive ion erosion, and is suitable for complex tunnel environments such as high groundwater level and freeze-thaw cycles, thus extending the service life of the repair body. Detailed Implementation

[0042] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0043] As mentioned above, current mainstream repair materials, such as ordinary cement-based grouting materials and polymer-modified cement-based materials, can seal cracks in the short term, but lack long-term self-healing capabilities and are prone to cracking again after repair. Existing self-healing technologies mostly rely on special chemical additives, which have drawbacks such as high cost and complex construction, and have not effectively solved the problem of solid waste disposal such as marine silt. Therefore, this invention provides a cement-based composite material with solid waste resource utilization as its core, which combines high-efficiency self-healing and anti-shrinkage properties and is suitable for high groundwater level environments, in order to solve the above problems.

[0044] The first typical embodiment of the present invention provides a tunnel crack repair material containing a modified marine silt carrier, comprising the following components by weight: 48-58 parts of ultrafine cement, 5-10 parts of anti-shrinkage self-healing component, 10-16 parts of polymer emulsion, 5-12 parts of anti-corrosion component, 3-7 parts of quick-setting stabilizer, 0.8-2.2 parts of high-efficiency water-reducing agent, 1-4 parts of penetration promoter, and 18-26 parts of water.

[0045] In one or more embodiments of this implementation, the tunnel crack repair material, by weight, comprises the following components: 53 parts ultrafine cement, 8 parts anti-shrinkage self-healing component, 13 parts polymer emulsion, 8 parts anti-corrosion component, 5 parts quick-setting stabilizer, 1.5 parts high-efficiency water-reducing agent, 2 parts penetration promoter, and 22 parts water.

[0046] In one or more embodiments of this implementation, the ultrafine cement is selected from one or more of silicate ultrafine cement, sulfoaluminate ultrafine cement, and ferroaluminate ultrafine cement, with a particle size of 5~10 μm and a specific surface area of ​​600~800 m² / kg.

[0047] In one or more embodiments of this implementation, the anti-shrinkage self-healing component is composed of ettringite-type expanding agent, sodium polyacrylate water-retaining agent and modified marine silt self-healing carrier particles mixed in a mass ratio of 3~4:1:2~3, wherein the modified marine silt self-healing carrier particles are etched water-saturated particles with a cement-silica-nano silica composite shell on the surface.

[0048] In one or more embodiments of this implementation, the etched water-saturated particles have a particle size of 40-80 μm and a water saturation rate of 35%-45%; the coating solution used for surface coating is prepared by ordinary silicate cement, silica fume, nano silica, polycarboxylate superplasticizer and water in a mass ratio of 150-170:25-35:5-8:1.5-2:70-90 to form a coating layer with a thickness of 2-5 μm.

[0049] In one or more embodiments of this implementation, the ettringite-type expanding agent, sodium polyacrylate water-retaining agent, and modified marine silt self-healing carrier particles are mixed in a mass ratio of 3:1:2.

[0050] In one or more embodiments of this implementation, the polymer emulsion is an acrylate-styrene-butadiene rubber composite emulsion, wherein the mass ratio of acrylate to styrene-butadiene rubber in the composite emulsion is 3~5:1.

[0051] In one or more embodiments of this implementation, the mass ratio of acrylate to styrene-butadiene rubber in the composite emulsion is 4:1.

[0052] In one or more embodiments of this implementation, the polymer emulsion has a solid content of 45% to 60%, a glass transition temperature (Tg) of -20 to 10°C, and a minimum film-forming temperature (MFT) of ≤5°C.

[0053] In one or more embodiments of this implementation, the anti-corrosion component is composed of slag powder, silica fume and rust inhibitor mixed in a mass ratio of 4~5:2~3:1, wherein the slag powder has a particle size of 1~3 μm, the silica fume has a particle size of 0.1~0.5 μm, and the rust inhibitor is calcium nitrite or an amino alcohol rust inhibitor.

[0054] In one or more embodiments of this implementation, the quick-setting stabilizer is a mixture of aluminate quick-setting agent and clay minerals in a mass ratio of 2 to 3:1.

[0055] In one or more embodiments of this implementation, the ratio of the aluminate quick-setting agent to clay minerals is 2:1.

[0056] In one or more embodiments of this implementation, the high-efficiency water-reducing agent is a polycarboxylate-based high-efficiency water-reducing agent with a water reduction rate of ≥25%.

[0057] In one or more embodiments of this implementation, the penetration enhancer is an organosilicon penetration enhancer, and the effective component (organosilicon) is 98%.

[0058] A second typical embodiment of the present invention provides a method for preparing the above-mentioned tunnel crack repair material, comprising the following steps: After drying the marine silt, it is ground and sieved. The silt powder is mixed with a polyvinyl alcohol aqueous solution and granulated to obtain silt-based core particles. Then, the silt-based core particles are placed in a composite etching solution and stirred. After the reaction is completed, etched marine silt porous particles are obtained. Then, the etched marine silt porous particles were vacuumed to remove the air from the pores and water was introduced. The pressure was restored to normal and the particles were allowed to stand to fully absorb water and reach a supersaturated state. The saturated particles were then mixed with the coating liquid and stirred to obtain modified marine silt self-healing carrier particles. A shrinkage-resistant self-healing component is obtained by mixing ettringite-type expansive agent, sodium polyacrylate water-retaining agent, and modified marine silt self-healing carrier particles. Then, ultrafine cement, shrinkage-resistant self-healing component, corrosion-resistant component, quick-setting stabilizer, and high-efficiency water-reducing agent are mixed evenly to obtain a dry powder mixture. Then, a penetration promoter and water are added to the dry powder mixture, and after stirring, a polymer emulsion is added to obtain the final product.

[0059] In one or more embodiments of this implementation, the drying temperature is 105~110℃, the grinding speed is 300~400 rpm, the grinding time is 30~45 min, and the sieve particle size is 500 mesh.

[0060] In one or more embodiments of this implementation, the ratio of the sludge powder to the polyvinyl alcohol aqueous solution is 1:0.8~1.2; the particle size of the sludge-based core particles is 35~75 μm.

[0061] In one or more embodiments of this implementation, the composite etching solution is prepared by mixing a 1.5 M HCl solution and a 5% H2O2 solution; the solid-liquid ratio of the silt-based core particles to the composite etching solution is 1:5.

[0062] In one or more embodiments of this implementation, the silt-based core particles are mixed with the composite etching solution and stirred at a speed of 180-220 rpm for 45-60 minutes in a constant temperature water bath at 45-50°C. After the reaction is completed, the mixture is washed and dried at 70-90°C for 10-15 hours to obtain etched marine silt porous particles.

[0063] In one or more embodiments of this implementation, the vacuuming process is performed at a pressure lower than -0.09 MPa for 30 minutes to expel pore air; the settling time is 36-48 hours to allow the particles to reach a supersaturated water content state.

[0064] In one or more embodiments of this implementation, the stirring speed is 150~180 rpm and the stirring time is 120~150 s, to ensure that a dense cement-silica-nano silica composite coating layer with a thickness of 2~5 μm is formed on the particle surface.

[0065] In one or more embodiments of this implementation, the particles obtained after stirring are first air-dried in an environment with a relative humidity of 60%~70% for 20~30 hours, and finally passed through a 150-mesh sieve to obtain modified marine silt self-healing carrier particles.

[0066] In one or more embodiments of this implementation, the stirring is first carried out at 100~120 r / min for 2~3 min, after adding the polymer emulsion, the speed is adjusted to 150~180 r / min and stirring is continued for 3~5 min, and finally the viscosity of the slurry of the tunnel crack repair material is controlled to be 500~1500 mPa·s.

[0067] A third typical embodiment of the present invention provides a repair method for the above-mentioned tunnel crack repair material, comprising the following steps: After the crack is pretreated, a V-shaped groove is chiseled along the direction of the crack extension. Then, the water is diverted according to the seepage flow rate. The grouting pressure is adjusted according to the crack width for grouting. After grouting, the V-shaped groove is filled and smoothed with the tunnel crack repair material described in the first aspect. Finally, the repair surface is subjected to adaptive curing.

[0068] In one or more embodiments of this implementation, the crack pretreatment includes mechanical dust removal and chemical degreasing of the crack base surface to remove debris, laitance and loose concrete from the tunnel crack surface.

[0069] In one or more embodiments of this implementation, after the V-groove is excavated, compressed air is used to remove the cracks and dust in the V-groove, and organic solvent is used to clean the inner wall and the surface of the groove. Then, corresponding diversion measures are taken according to the water flow rate. More preferably, the organic solvent is selected from one or more of acetone, anhydrous ethanol, and isopropanol.

[0070] In one or more embodiments of this implementation, the width of the V-groove is 5-10 mm and the depth is 3-8 mm.

[0071] In one or more embodiments of this implementation, when the seepage flow rate is ≤0.5 mL / min, the flow is directly guided by a drainage pipe; if the seepage flow rate is >0.5 mL / min, 45° inclined drainage holes are drilled on both sides of the crack, and the drainage pipe is inserted after being staggered to control the seepage flow rate to ≤0.5 mL / min. The spacing between the drainage holes is 50~80 cm, the hole diameter is 12~16 mm, and the hole depth is 1.2~1.8 times the crack depth.

[0072] In one or more embodiments of this implementation, microcracks with a crack width < 0.1 mm are grouted with low-pressure permeation at 0.1~0.3 MPa; fine cracks with a crack width of 0.1~2 mm are grouted with medium-pressure at 0.3~0.6 MPa; and medium-wide / wide cracks with a crack width ≥ 2 mm are grouted with high-pressure at 0.6~1.0 MPa.

[0073] In one or more embodiments of this implementation, after the grouting is completed, the pressure is stabilized for 3 to 5 minutes to ensure that the cracks are filled densely.

[0074] In one or more embodiments of this implementation, the adaptive maintenance includes covering the repair surface with a moisturizing maintenance cloth to maintain humidity ≥90% and a maintenance temperature of 5~35℃; or during winter construction, applying a heat-insulating maintenance agent or building a heat-insulating shed to ensure that the temperature is not lower than 5℃.

[0075] In one or more embodiments of this implementation, the adaptation curing time is no less than 14 days. During the first 7 days, water is sprayed 2-3 times a day. After the curing is completed, the filling density is tested, the water pressure test is performed, and the interface bonding strength is tested by pull-out test. If it fails, it is removed and repaired. The water pressure test is conducted at 1.2-1.5 times the groundwater pressure, that is, it is considered qualified if there is no leakage after 30 minutes of constant pressure. The interface bonding strength is ≥3.5 MPa in the pull-out test.

[0076] The fourth typical embodiment of the present invention provides an application of the tunnel crack repair material described in the first typical embodiment and / or the repair method described in the third typical embodiment in a high groundwater level environment.

[0077] In one or more embodiments of this implementation, the high groundwater level environment includes subway tunnels, highway tunnels, water conservancy tunnels, underground integrated pipe corridors, and hydraulic dam corridors.

[0078] Raw materials and their functions: Anti-shrinkage self-healing components: Eundumite-type expansive agent hydrates to form ettringite crystals, producing moderate volume expansion to compensate for material hydration and drying shrinkage; sodium polyacrylate-based water-retaining agent adsorbs and locks in moisture, prolonging hydration time and reducing drying shrinkage cracks; modified marine silt carrier particles are etched to form a porous structure, which stores a large amount of water after vacuum saturation. When cracks occur in the repair, internal stress breaks the surface composite shell, releasing moisture and triggering a secondary hydration reaction to fill the cracks and achieve self-healing. In addition, trace amounts of active minerals in the silt can strengthen the strength of the repair, and residual organic components form a chemical anchor with the polymer emulsion, improving interface stability.

[0079] Polymer emulsion: The acrylate component can form a chemical bond with cement hydration products, improving the bond strength between the repair and the old concrete interface; the styrene-butadiene rubber component gives the material good flexibility and deformation capacity, reduces brittleness, and makes the elastic modulus of the repair precisely match that of the tunnel lining concrete, adapting to small deformations caused by substrate softening and reducing the risk of cracking again; after the emulsion forms a film, it seals the internal capillary pores of the repair, enhancing impermeability and water resistance.

[0080] Anti-corrosion component: The anti-corrosion component is a mixture of slag powder, silica fume, and rust inhibitor in a specific ratio. The filling and densifying effect of the slag powder and silica fume, combined with the rust-inhibiting function of the rust inhibitor, effectively resists SO4 in groundwater. 2- Cl - It resists corrosive ion erosion while inhibiting steel corrosion.

[0081] Accelerating stabilizer: The aluminate accelerator in the accelerating stabilizer is combined with clay minerals (bentonite, attapulgite) in a specific ratio, which can accelerate the setting speed of the material, significantly improve the material's resistance to erosion and segregation in dynamic water environment, and ensure that the slurry is stable and does not run off when construction is carried out in water.

[0082] High-efficiency water-reducing agent: The addition of high-efficiency water-reducing agent can reduce the water-cement ratio and further improve the material density. The synergistic effect of each component constructs a multi-mechanism repair system, realizing full-range, long-term, and crack-resistant repair of tunnel cracks under karst hydrogeological conditions.

[0083] Penetration enhancer: Organosilicon penetrants can effectively reduce the surface tension of grout and enhance its ability to wet and penetrate micro-cracks in concrete.

[0084] Water: The amount of water used must be appropriate for each component to ensure stable slurry performance.

[0085] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0086] Example 1: This example provides a tunnel crack repair material, its preparation method, and a tunnel crack repair method. The components of the tunnel crack repair material, by weight, include: 48 parts of ultrafine cement (particle size 5~8 μm, specific surface area 600~700 m² / kg), 5 parts of anti-shrinkage self-healing component (ettringite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 3:1:2), 10 parts of acrylate styrene-butadiene rubber composite emulsion (mass ratio 4:1, solid content 45%, Tg = -20~-10℃, MFT≤5℃), 5 parts of anti-corrosion component (slag powder: silica fume: calcium nitrite = 4:2:1), 3 parts of quick-setting stabilizer (aluminate quick-setting agent: bentonite = 2:1), 0.8 parts of polycarboxylate-based high-efficiency water-reducing agent (water reduction rate 25%, solid content 40%), 1 part of organosilicon penetrant (effective ingredient 98%), and 18 parts of water.

[0087] The specific preparation method of tunnel crack repair material includes the following steps: Marine silt was placed in a forced-air drying oven and dried at 105℃ to constant weight. The dried silt was then placed in a ball mill and ground at 300 rpm for 30 min. The silt powder was obtained by passing it through a 500-mesh standard sieve. The silt powder and polyvinyl alcohol aqueous solution were mixed at a mass ratio of 1:0.8 and granulated using a granulator to obtain silt-based core particles with a particle size of 35-50 μm. A composite etching solution (equal volumes of 1.5 M HCl solution and 5% H2O2 solution) was prepared. The silt-based core particles and the composite etching solution were mixed at a solid-liquid ratio of 1:5 and placed in a 45℃ constant temperature water bath, stirred at 180 rpm for 45 min. After the reaction, the mixture was repeatedly washed with deionized water until neutral and then dried in a drying oven at 75℃ for 10 h to obtain etched porous marine silt particles. The etched porous marine silt particles were placed in a vacuum drying oven, evacuated to a pressure of -0.092 MPa and maintained for 30 min, then rapidly injected with deionized water. After restoring to normal pressure, the particles were allowed to stand for 36 h to reach a supersaturated water content. A coating solution (ordinary silicate cement: silica fume: nano silica: polycarboxylate superplasticizer: water) was prepared at a mass ratio of 150:25:5:1.5:70. The saturated particles and the coating solution were mixed at a solid-liquid ratio of 1:3 and stirred at 150 rpm for 120 s to form a 2-3 μm thick composite coating layer on the particle surface. The coated particles were then air-dried in an environment with a relative humidity of 60% for 20 h and passed through a 150-mesh sieve to obtain modified marine silt self-healing carrier particles (water saturation rate 35%-38%, particle size 40-60 μm).

[0088] According to the mass ratio of ettringite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 3:1:2, the three raw materials are put into a horizontal mixer and mixed at 100 rpm for 5 min to obtain a uniform anti-shrinkage self-healing component for later use.

[0089] According to the formula, take the ultrafine cement, the prepared anti-shrinkage self-healing component, the anti-corrosion component, the quick-setting stabilizer, and the polycarboxylate-based high-efficiency water-reducing agent, put them into a planetary mixer, and dry mix at 100 r / min for 2 min to obtain a uniform dry powder mixture; add the formula amount of organosilicon penetrant and water to the dry powder mixture, and stir at 100 r / min for 2 min to fully wet the dry powder; add the formula amount of acrylate styrene-butadiene rubber composite emulsion, adjust the stirring speed to 150 r / min, and continue stirring for 3 min to obtain the tunnel crack repair material slurry with a viscosity of 1300~1500 mPa·s.

[0090] The method for repairing tunnel cracks includes the following steps: Mechanical dust removal and chemical degreasing were performed on the 0.8 mm wide fine crack base surface. A 5 mm × 3 mm V-groove was chiseled, and the dust was removed with compressed air and cleaned with acetone. The seepage flow rate was 0.3 mL / min, and a diversion pipe was used for drainage. Prepare a dry powder mixture according to the formula, add a penetration promoter and water and stir for 2 min, then add a polymer emulsion and stir for 3 min to obtain a slurry with a viscosity of 1300~1500 mPa·s; use medium pressure grouting of 0.3~0.5MPa, starting from the lowest point until the slurry overflows, and stabilize the pressure for 3 min; fill the V-shaped groove with the slurry, smooth and compact it; cover with a moisture-retaining curing cloth, maintain humidity ≥90%, control the temperature at 10~25℃, and cure for 14 days; test results show that the filling density is 95%, there is no leakage in the water pressure test (1.2 times the groundwater level pressure), the bonding strength is 3.8 MPa, and the resistance to chloride ion penetration and sulfate erosion is qualified, and the repair is qualified.

[0091] Example 2: This example provides a tunnel crack repair material, its preparation method, and a tunnel crack repair method. By weight, the components of the tunnel crack repair material include: 53 parts ultrafine cement (particle size 6~10 μm, specific surface area 700~800 m²). 2 / kg), anti-shrinkage self-healing component (ettringite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 3:1:2) 8 parts, acrylate styrene-butadiene rubber composite emulsion (mass ratio 4:1, solid content 50%, Tg = -10~5℃, MFT≤3℃) 13 parts, anti-corrosion component (slag powder: silica fume: amino alcohol rust inhibitor = 4:2:1) 8 parts, quick-setting stabilizer (aluminate quick-setting agent: bentonite = 2:1) 5 parts, polycarboxylate-based high-efficiency water-reducing agent (water reduction rate 28%, solid content 45%) 1.5 parts, organosilicon penetrant (active ingredient 98%) 2 parts, water 22 parts.

[0092] The specific preparation method of tunnel crack repair material includes the following steps: Marine silt was placed in a forced-air drying oven and dried at 108℃ to constant weight. The dried silt was then placed in a ball mill and ground at 350 rpm for 38 min. The silt powder was obtained by passing it through a 500-mesh standard sieve. The silt powder and polyvinyl alcohol aqueous solution were mixed at a mass ratio of 1:1.0 and granulated using a granulator to obtain silt-based core particles with a particle size of 45-65 μm. A composite etching solution (equal volumes of 1.5 M HCl solution and 5% H2O2 solution) was prepared. The silt-based core particles and the composite etching solution were mixed at a solid-liquid ratio of 1:5 and placed in a constant temperature water bath at 48℃. The mixture was stirred at 200 rpm for 52 min. After the reaction, the mixture was repeatedly washed with deionized water until neutral and then dried in a drying oven at 82℃ for 12 h to obtain etched porous marine silt particles. The etched porous marine silt particles were placed in a vacuum drying oven, evacuated to a pressure of -0.095 MPa and maintained for 30 min, then rapidly injected with deionized water. After restoring to normal pressure, the particles were allowed to stand for 42 h to reach a supersaturated water content. A coating solution (ordinary silicate cement: silica fume: nano silica: polycarboxylate superplasticizer: water) was prepared at a mass ratio of 160:30:6:1.8:80. The saturated particles and the coating solution were mixed at a solid-liquid ratio of 1:3 and stirred at 165 rpm for 135 s to form a 3-4 μm thick composite coating layer on the particle surface. The coated particles were then air-dried in an environment with a relative humidity of 65% for 24 h and passed through a 150-mesh sieve to obtain modified marine silt self-healing carrier particles (water saturation rate 40%-42%, particle size 50-70 μm).

[0093] According to the mass ratio of ettringite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 3:1:2, the three raw materials are put into a horizontal mixer and mixed at 100 rpm for 6 min to obtain a uniform anti-shrinkage self-healing component for later use.

[0094] According to the formula, take the ultrafine cement, the prepared anti-shrinkage self-healing component, the anti-corrosion component, the quick-setting stabilizer, and the polycarboxylate-based high-efficiency water-reducing agent, put them into a planetary mixer, and dry mix at 110 r / min for 2.5 min to obtain a uniform dry powder mixture; add the formula amount of organosilicon penetrant and water to the dry powder mixture, and stir at 110 r / min for 2.5 min to fully wet the dry powder; add the formula amount of acrylate styrene-butadiene rubber composite emulsion, adjust the stirring speed to 165 r / min, and continue stirring for 4 min to obtain the tunnel crack repair material slurry with a viscosity of 800~1000 mPa·s.

[0095] The method for repairing tunnel cracks includes the following steps: Mechanical dust removal and chemical degreasing were performed on the 2.5 mm wide crack base surface. An 8 mm × 6 mm V-groove was chiseled, and the dust was removed with compressed air and cleaned with acetone. The seepage flow rate was 0.7 mL / min. 45° inclined drainage holes were drilled (hole spacing 60 cm, hole diameter 14 mm) and the water was guided through the diversion pipe to a seepage flow rate of 0.4 mL / min. Prepare a dry powder mixture according to the formula, add a penetration promoter and water and stir for 2.5 min, then add a polymer emulsion and stir for 4 min to obtain a slurry with a viscosity of 800~1000 mPa·s; use 0.7~0.9 MPa high-pressure grouting, starting from the lowest point until the slurry overflows, and maintain pressure for 4 min; fill the V-shaped groove with the slurry, smooth and compact it; during winter construction, cover with a moisture-retaining curing cloth and apply a heat-insulating curing agent, control the temperature at 5~10℃, and cure for 16 days; the test results show that the filling density is 98%, there is no leakage in the water pressure test (1.4 times the groundwater level pressure), the bonding strength is 4.5 MPa, and the resistance to chloride ion penetration and sulfate erosion is qualified, and the repair is qualified.

[0096] Example 3: This example provides a tunnel crack repair material, its preparation method, and a tunnel crack repair method. The components of the tunnel crack repair material, by weight, include: 58 parts ultrafine cement, 10 parts anti-shrinkage self-healing component (calcite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 3:1:2), 16 parts acrylate styrene-butadiene rubber composite emulsion (mass ratio 5:1, solid content 60%, Tg = 0~10℃, MFT ≤ 2℃), 12 parts anti-corrosion component (slag powder: silica fume: calcium nitrite = 5:3:1), 7 parts quick-setting stabilizer (aluminate quick-setting agent: attapulgite = 3:1), 2.2 parts polycarboxylate-based high-efficiency water-reducing agent (water reduction rate 30%, solid content 50%), 4 parts organosilicon penetrant (effective ingredient 98%), and 26 parts water.

[0097] The specific preparation method of tunnel crack repair material includes the following steps: Marine silt was placed in a forced-air drying oven and dried at 110℃ to constant weight. The dried silt was then placed in a ball mill and ground at 400 rpm for 45 min. The silt powder was obtained by passing it through a 500-mesh standard sieve. The silt powder and polyvinyl alcohol aqueous solution were mixed at a mass ratio of 1:1.2 and granulated using a granulator to obtain silt-based core particles with a particle size of 60-75 μm. A composite etching solution (equal volumes of 1.5 M HCl solution and 5% H2O2 solution) was prepared. The silt-based core particles and the composite etching solution were mixed at a solid-liquid ratio of 1:5 and placed in a 50℃ constant temperature water bath, stirred at 220 rpm for 60 min. After the reaction, the mixture was repeatedly washed with deionized water until neutral and then dried in a drying oven at 90℃ for 15 h to obtain etched porous marine silt particles. The etched porous marine silt particles were placed in a vacuum drying oven, evacuated to a pressure of -0.098 MPa and maintained for 30 minutes, then rapidly injected with deionized water. After restoring to normal pressure, the particles were allowed to stand for 48 hours to reach a supersaturated water content. A coating solution (ordinary silicate cement: silica fume: nano silica: polycarboxylate superplasticizer: water) was prepared at a mass ratio of 170:35:8:2.0:90. The saturated particles and the coating solution were mixed at a solid-liquid ratio of 1:3 and stirred at 180 rpm for 150 seconds to form a 4-5 μm thick composite coating layer on the particle surface. The coated particles were then air-dried in an environment with a relative humidity of 70% for 30 hours and passed through a 150-mesh sieve to obtain modified marine silt self-healing carrier particles (water saturation rate 43%-45%, particle size 60-80 μm).

[0098] According to the mass ratio of ettringite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 4:1:4, the three raw materials are put into a horizontal mixer and mixed at 100 rpm for 7 min to obtain a uniform anti-shrinkage self-healing component for later use.

[0099] According to the formula, take the ultrafine cement, the prepared anti-shrinkage self-healing component, the anti-corrosion component, the quick-setting stabilizer, and the polycarboxylate-based high-efficiency water-reducing agent, put them into a planetary mixer, and dry mix at 120 r / min for 3 min to obtain a uniform dry powder mixture; add the formula amount of organosilicon penetrant and water to the dry powder mixture, and stir at 120 r / min for 3 min to fully wet the dry powder; add the formula amount of acrylate styrene-butadiene rubber composite emulsion, adjust the stirring speed to 180 r / min, and continue stirring for 5 min to obtain the tunnel crack repair material slurry with a viscosity of 500~700 mPa·s.

[0100] The method for repairing tunnel cracks includes the following steps: The repair of a 0.08 mm wide microcrack followed the same procedures as in Example 2, including crack pretreatment, grouting, surface sealing, curing, and testing. The only difference was the grouting pressure: low-pressure permeable grouting of 0.1–0.2 MPa, pressure stabilization for 5 minutes, curing temperature controlled at 20–35℃, and curing for 18 days. All raw material specifications and preparation methods were identical to those in Example 2. Test results showed a 99% filling density, no leakage in the water pressure test (1.5 times the groundwater level), a bond strength of 5.2 MPa, and satisfactory resistance to chloride ion penetration and sulfate attack. The repair was deemed successful.

[0101] Comparative Example 1: The difference between this comparative example and Example 2 is that the marine silt-based core particles were not etched, while the other components and preparation methods are the same as in Example 2.

[0102] Comparative Example 2: The difference between this comparative example and Example 2 is that the porous particles of etched marine silt were not subjected to composite coating treatment, while the other components and preparation methods are the same as in Example 2.

[0103] Comparative Example 3: The difference between this comparative example and Example 2 is that no modified marine silt self-healing carrier particles were added, while the other components and preparation methods are the same as in Example 2.

[0104] Comparative Example 4: The difference between this comparative example and Example 2 is that the amount of modified marine silt self-healing carrier particles added to the anti-shrinkage self-healing component is reduced. The specific mass ratio is: anti-shrinkage self-healing component (ettringite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 3:1:0.5, and other components and preparation methods are the same as in Example 2.

[0105] Comparative Example 5: The difference between this comparative example and Example 2 is that the amount of modified marine silt self-healing carrier particles added to the anti-shrinkage self-healing component is increased. The specific mass ratio is: anti-shrinkage self-healing component (ettringite-type expanding agent: sodium polyacrylate water-retaining agent: modified marine silt self-healing carrier particles = 3:1:5). The other components and preparation methods are the same as in Example 2.

[0106] Comparative Example 6: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component was added, while the other components and preparation methods are the same as in Example 2.

[0107] Comparative Example 7: The difference between this comparative example and Example 2 is that no polymer emulsion was added, while the other components and preparation methods are the same as in Example 2.

[0108] Comparative Example 8: The difference between this comparative example and Example 2 is that the mass ratio of acrylate to styrene-butadiene rubber in the polymer emulsion is 2:1, while the other components and preparation methods are the same as in Example 2.

[0109] Comparative Example 9: The difference between this comparative example and Example 2 is that the mass ratio of acrylate to styrene-butadiene rubber in the polymer emulsion is 6:1, while the other components and preparation methods are the same as in Example 2.

[0110] Comparative Example 10: The difference between this comparative example and Example 2 is that no anti-corrosion component was added, while the other components and preparation methods are the same as in Example 2.

[0111] Comparative Example 11: The difference between this comparative example and Example 2 is that no quick-setting stabilizer was added, while the other components and preparation methods are the same as in Example 2.

[0112] Comparative Example 12: The difference between this comparative example and Example 2 is that no penetration enhancer was added, while the other components and preparation methods are the same as in Example 2.

[0113] Comparative Example 13: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component and polymer emulsion were added, while the other components and preparation methods are the same as in Example 2.

[0114] Comparative Example 14: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component and anti-corrosion component were added, while the other components and preparation methods are the same as in Example 2.

[0115] Comparative Example 15: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component and quick-setting stabilizer were added, while the other components and preparation methods are the same as in Example 2.

[0116] Comparative Example 16: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component and penetration promoter were added, while the other components and preparation methods are the same as in Example 2.

[0117] Comparative Example 17: The difference between this comparative example and Example 2 is that no anti-corrosion components and polymer emulsion were added, while the other components and preparation methods are the same as in Example 2.

[0118] Comparative Example 18: The difference between this comparative example and Example 2 is that no quick-setting stabilizer and polymer emulsion were added, while the other components and preparation methods are the same as in Example 2.

[0119] Comparative Example 19: The difference between this comparative example and Example 2 is that no penetration enhancer or polymer emulsion was added, while the other components and preparation methods are the same as in Example 2.

[0120] Comparative Example 20: The difference between this comparative example and Example 2 is that no anti-corrosion components and quick-setting stabilizers were added, while the other components and preparation methods are the same as in Example 2.

[0121] Comparative Example 21: The difference between this comparative example and Example 2 is that no anti-corrosion components and penetration enhancers were added, while the other components and preparation methods are the same as in Example 2.

[0122] Comparative Example 22: The difference between this comparative example and Example 2 is that no quick-setting stabilizer and penetration promoter were added, while the other components and preparation methods are the same as in Example 2.

[0123] Comparative Example 23: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component, polymer emulsion, and anti-corrosion component were added; all other components and preparation methods are the same as in Example 2.

[0124] Comparative Example 24: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component, polymer emulsion, and quick-setting stabilizer were added; all other components and preparation methods are the same as in Example 2.

[0125] Comparative Example 25: The difference between this comparative example and Example 2 is that no anti-shrinkage self-healing component, polymer emulsion, and penetration enhancer were added; all other components and preparation methods are the same as in Example 2.

[0126] Comparative Example 26: The difference between this comparative example and Example 2 is that no polymer emulsion, anti-corrosion components, and quick-setting stabilizer were added; all other components and preparation methods are the same as in Example 2.

[0127] Comparative Example 27: The difference between this comparative example and Example 2 is that no polymer emulsion, anti-corrosion components, and penetration enhancers were added; all other components and preparation methods are the same as in Example 2.

[0128] Comparative Example 28: The difference between this comparative example and Example 2 is that no anti-corrosion components, quick-setting stabilizers, and penetration promoters were added; all other components and preparation methods are the same as in Example 2.

[0129] Experimental Example 1: In order to verify the technical effect of the tunnel crack repair material of the present invention, this experimental example conducts performance tests on the repair materials prepared in the above embodiments and comparative examples.

[0130] The test items included 28-day compressive strength, 28-day interfacial bond strength, 7-day crack self-healing efficiency, material retention rate under 0.8 MPa flowing water pressure, and 28-day drying shrinkage. The performance test results of each component are shown in Table 1. Table 1

[0131] Analysis of the data in Table 1 shows that: (1) Compared with Example 2, Examples 1 and 3 are complete component examples with different proportions. The amount of ultrafine cement and functional components added in Example 1 is relatively low. Although the amount of some components added in Example 3 is increased, the compatibility is slightly inferior to that of Example 2. The compressive strength, self-healing efficiency, and water pressure retention rate of both are lower than those of Example 2, and the drying shrinkage rate is also higher. This proves that the proportion of Example 2 is the optimal proportion for the synergistic effect of each component, which can maximize the improvement of various properties.

[0132] (2) Compared with Example 2, Comparative Example 4 and Comparative Example 5 differ only in the proportion of marine silt carrier particles in the anti-shrinkage self-healing component. Too little (Comparative Example 4) or too much (Comparative Example 5) carrier particles significantly reduce the self-healing efficiency. The self-healing efficiency of Comparative Example 4 is only 73.2% and that of Comparative Example 5 is only 33.5%. Moreover, excessive addition will severely dilute the cementitious system, causing the compressive strength to drop to 36.5 MPa and the interfacial bonding strength to be only 2.5 MPa, verifying that 3:1:2 is the optimal proportion of carrier particles.

[0133] (3) Compared with Example 2, Comparative Examples 6-12 either lacked a single component or had deviations in the proportion of a single component. Comparative Example 6, lacking the anti-shrinkage self-healing component, saw its drying shrinkage rate rise to 0.041%, with a self-healing efficiency of only 42.6%, representing the largest single missing component in terms of performance degradation. This demonstrates that the anti-shrinkage component is the core component for compensating for shrinkage and achieving self-healing. Comparative Example 7, lacking the polymer emulsion, experienced a decrease in interfacial bond strength to 2.6 MPa and a significant increase in brittleness, indicating that the emulsion is crucial for improving interfacial bond, reducing brittleness, and matching the deformation of the lining concrete. In Comparative Examples 8 and 9, the proportions of the polymer emulsions changed, with the acrylate to styrene-butadiene rubber ratio deviating from the 3-5:1 range, resulting in interfacial bond strengths decreasing to 2.3 MPa and 3.8 MPa, respectively. The self-healing efficiency was also lower than that of Example 2, proving that this ratio is the optimal range for the emulsion to exert a synergistic effect of adhesion and toughness. Comparative Example 10 did not add any anti-corrosion components, and its core performance did not decrease significantly in the short term, with only the water retention rate dropping to 66.5%. Its main function is to resist long-term corrosive ion erosion and improve the durability of the repair. Comparative Example 11 did not add any quick-setting stabilizer, and its water retention rate dropped sharply to 68.8%, indicating that it is the core of improving the material's resistance to erosion in dynamic water environments. Comparative Example 12 did not add any penetration promoter, and its self-healing efficiency dropped sharply to 30.2% and its compressive strength was only 32.5 MPa. This was because the penetration ability of the slurry to microcracks decreased significantly, and the cracks were not filled sufficiently, proving that it is the key to improving the penetration and sealing ability of microcracks.

[0134] (4) Compared with Example 2, Comparative Examples 13-28 lacked multiple components. If two or more components are missing at the same time, it will lead to a significant reduction in at least one core property of the material, and the more components are missing, the greater the performance reduction.

[0135] Comparative Examples 13, 23, 24, and 25 lacked core components such as anti-shrinkage self-healing components and polymer emulsions, resulting in interfacial bonding strengths of less than 2.4 MPa for all four combinations, which completely failed to meet repair requirements. Comparative Examples 14, 17, 19, 21, 23, 25, and 27 lacked anti-corrosion components and other components, resulting in water retention rates of less than 65.5% for all seven combinations. In dynamic water environments with high groundwater levels, these water retention rates would rapidly dissipate, failing to achieve effective sealing. Comparative Examples 12, 16, 18, 22, 24, 26, and 28 lacked penetration promoters and other components, resulting in self-healing efficiencies of less than 73.0% for all seven combinations. This led to insufficient sealing of microcracks, making them prone to re-cracking after repair.

[0136] The results show that the anti-shrinkage self-healing component based on marine silt carrier particles, in synergy with the other components, significantly improves the composite material in terms of mechanical properties, permeability plugging, corrosion resistance, and self-healing.

Claims

1. A tunnel crack repair material containing a modified marine silt carrier, characterized in that, By weight, it includes the following components: 48-58 parts ultrafine cement, 5-10 parts anti-shrinkage self-healing component, 10-16 parts polymer emulsion, 5-12 parts anti-corrosion component, 3-7 parts quick-setting stabilizer, 0.8-2.2 parts high-efficiency water-reducing agent, 1-4 parts penetration promoter, and 18-26 parts water. The anti-shrinkage self-healing component is composed of ettringite-type expanding agent, sodium polyacrylate water-retaining agent and modified marine silt self-healing carrier particles mixed in a mass ratio of 3~4:1:2~3; wherein, the modified marine silt self-healing carrier particles are etched water-saturated particles with a cement-silica-nano silica composite shell on the surface. The etched water-saturated particles have a particle size of 40-80 μm and a water saturation rate of 35%-45%; the coating solution used for surface coating is prepared by ordinary silicate cement, silica fume, nano silica, polycarboxylate superplasticizer and water in a mass ratio of 150-170:25-35:5-8:1.5-2:70-90 to form a coating layer with a thickness of 2-5 μm; The ultrafine cement is selected from one or more of silicate ultrafine cement, sulfoaluminate ultrafine cement, and ferroaluminate ultrafine cement, with a particle size of 5~10 μm and a specific surface area of ​​600~800 m² / kg. The polymer emulsion is an acrylate-styrene-butadiene rubber composite emulsion, wherein the mass ratio of acrylate to styrene-butadiene rubber in the composite emulsion is 3~5:1; the solid content of the polymer emulsion is 45%~60%, the glass transition temperature is -20~10℃, and the minimum film-forming temperature is ≤5℃. The anti-corrosion component is composed of slag powder, silica fume and rust inhibitor mixed in a mass ratio of 4~5:2~3:1, wherein the slag powder has a particle size of 1~3 μm, the silica fume has a particle size of 0.1~0.5 μm, and the rust inhibitor is calcium nitrite or amino alcohol rust inhibitor. The quick-setting stabilizer is composed of an aluminate quick-setting agent and clay minerals in a mass ratio of 2 to 3:1, wherein the clay minerals include bentonite and attapulgite. The high-efficiency water-reducing agent is a polycarboxylate-based high-efficiency water-reducing agent with a water reduction rate of ≥25%; The penetration enhancer is an organosilicon penetration agent with an effective ingredient content of 98%.

2. A method for preparing a tunnel crack repair material as described in claim 1, characterized in that, Includes the following steps: After drying the marine silt, it is ground and sieved. The silt powder is mixed with a polyvinyl alcohol aqueous solution and granulated to obtain silt-based core particles. Then, the silt-based core particles are placed in a composite etching solution and stirred. After the reaction is completed, etched marine silt porous particles are obtained. Then, the etched marine silt porous particles were vacuumed to remove the air from the pores and water was introduced. The pressure was restored to normal and the particles were allowed to stand to fully absorb water and reach a supersaturated state. The saturated particles were then mixed with the coating liquid and stirred to obtain modified marine silt self-healing carrier particles. A shrinkage-resistant self-healing component is obtained by mixing ettringite-type expansive agent, sodium polyacrylate water-retaining agent, and modified marine silt self-healing carrier particles. Then, ultrafine cement, shrinkage-resistant self-healing component, corrosion-resistant component, quick-setting stabilizer, and high-efficiency water-reducing agent are mixed evenly to obtain a dry powder mixture. Then, a penetration promoter and water are added to the dry powder mixture, and after stirring, a polymer emulsion is added to obtain the final product.

3. The preparation method according to claim 2, characterized in that, The drying temperature is 105~110℃, the grinding speed is 300~400 rpm, the grinding time is 30~45 min, and the particle size of the sieve is 500 mesh. The mass ratio of the sludge powder to the polyvinyl alcohol aqueous solution is 1:0.8~1.2; the particle size of the sludge-based core particles is 35~75 μm; The composite etching solution is prepared by mixing a 1.5 M HCl solution and a 5% H2O2 solution; the solid-liquid ratio of the silt-based core particles to the composite etching solution is 1:

5. After the silt-based core particles are mixed with the composite etching solution, they are stirred at a speed of 180-220 rpm for 45-60 min in a constant temperature water bath at 45-50℃. After the reaction is completed, the particles are washed and dried at 70-90℃ for 10-15 h to obtain etched marine silt porous particles.

4. The preparation method according to claim 2, characterized in that, The vacuuming process is performed at a pressure below -0.09 MPa for 30 minutes to expel pore air; the settling time is 36-48 hours to allow the particles to reach a supersaturated water content state. The stirring speed is 150~180 rpm and the stirring time is 120~150 s to ensure that a dense cement-silica-nano silica composite coating layer with a thickness of 2~5 μm is formed on the particle surface. The particles obtained after stirring are first air-dried in an environment with a relative humidity of 60%~70% for 20~30 hours, and finally passed through a 150-mesh sieve to obtain modified marine silt self-healing carrier particles.

5. The preparation method according to claim 2, characterized in that, The stirring process involves first stirring at 100-120 r / min for 2-3 minutes, then adding the polymer emulsion, adjusting the speed to 150-180 r / min and continuing stirring for 3-5 minutes, ultimately controlling the slurry viscosity of the tunnel crack repair material to be 500-1500 mPa·s.

6. A repair method for a tunnel crack repair material as described in claim 1, characterized in that, Includes the following steps: After the crack is pretreated, a V-shaped groove is chiseled along the direction of the crack extension. Then, the water is diverted according to the seepage flow rate. Then, the grouting pressure is adjusted according to the crack width to carry out the grouting operation. After the grouting is completed, the V-shaped groove is filled and smoothed with the tunnel crack repair material described in claim 1. Finally, the repair surface is subjected to adaptive curing operation.

7. The repair method as described in claim 6, characterized in that, The crack pretreatment includes mechanical dust removal and chemical degreasing of the crack base surface to remove debris, laitance and loose concrete from the tunnel crack surface; After the V-groove is excavated, compressed air is used to remove the cracks and dust inside the V-groove, and organic solvents are used to clean the inner wall and the surface of the groove. Then, corresponding diversion measures are taken according to the water flow rate. The width of the V-groove is 5~10 mm and the depth is 3~8 mm; When the seepage rate is ≤0.5 mL / min, the water is directly drained using a guide pipe; if the seepage rate is >0.5 mL / min, 45° inclined drainage holes are drilled on both sides of the crack, and the guide pipe is inserted after being staggered to control the seepage rate to ≤0.5 mL / min. The spacing between the drainage holes is 50~80 cm, the hole diameter is 12~16 mm, and the hole depth is 1.2~1.8 times the crack depth. Microcracks with a width < 0.1 mm are treated with low-pressure permeable grouting at 0.1~0.3 MPa; fine cracks with a width of 0.1~2 mm are treated with medium-pressure grouting at 0.3~0.6 MPa; and medium / wide cracks with a width ≥ 2 mm are treated with high-pressure grouting at 0.6~1.0 MPa. After the grouting is completed, the pressure is stabilized for 3-5 minutes to ensure that the cracks are filled tightly. The adaptive maintenance includes covering the repaired surface with a moisturizing maintenance cloth to maintain humidity ≥90% and a maintenance temperature of 5~35℃; or, during winter construction, applying a heat-insulating maintenance agent or building a heat-insulating shed to ensure that the temperature is not lower than 5℃. The adaptation curing period shall not be less than 14 days. During the first 7 days, water shall be sprayed 2-3 times a day. After the curing is completed, the filling density shall be tested, the water pressure test shall be conducted, and the interface bonding strength shall be tested by pull-out test. If the test fails, the part shall be removed and repaired. The water pressure test shall be conducted at 1.2-1.5 times the groundwater pressure, i.e., no leakage shall be considered as qualified after 30 minutes of constant pressure. The interface bonding strength shall be ≥3.5 MPa in the pull-out test.

8. The application of the tunnel crack repair material as described in claim 1 in the field of tunnels and underground engineering.

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