Modified silicate grouting material and preparation method thereof

Abstract

The invention discloses a modified silicate grouting material, which belongs to the technical field of silicate grouting materials and comprises the following components in parts by weight: a component A and a component B, the component A is 100 parts of industrial grade sodium silicate; 100 parts of the component B is prepared from the following raw materials: 40 to 60 parts of self-made silane grafted polymerized aluminum phosphate modified liquid, 5 to 15 parts of composite organic ester, 0.5 to 2 parts of silane coupling agent, 1 to 2.5 parts of nonionic surfactant, 1 to 3 parts of complexing agent and the balance of deionized water. According to the technical scheme, the problem that traditional water glass gel is prone to hydrolysis, shrinkage and even disintegration in a water environment can be greatly solved, and the service life of temporary reinforcement engineering is greatly prolonged.

Description

Technical Field

[0001] This invention belongs to the field of silicate grouting technology, specifically, it relates to a modified silicate grouting material and its preparation method. Background Technology

[0002] Temporary support and ground improvement in underground engineering are crucial aspects of shield tunnel launching and receiving, deep foundation pit excavation, and connecting passage construction. These projects often encounter water-rich, loose strata such as fine sand and gravel. These strata have small pores, high permeability, and extremely poor self-stabilizing ability, making them highly susceptible to water inrush, quicksand, or collapse accidents during excavation.

[0003] Grouting reinforcement for this type of stratum places extremely stringent and contradictory requirements on material properties: on the one hand, it needs to have ultra-low viscosity at the level of a true solution to achieve effective penetration into micropores and avoid the filter cake effect similar to cement-based grouts; on the other hand, unlike permanent foundation reinforcement, this type of project is often a temporary reinforcement, requiring the grout to provide sufficient strength and water-stopping properties during the construction period, but also to be able to be smoothly cut and excavated by the cutterhead of the tunnel boring machine or other mechanical equipment in the later stages of construction.

[0004] Traditional sodium silicate slurry is widely used for temporary reinforcement due to its low cost and low viscosity; however, its poor water resistance is a well-known drawback among those skilled in the art.

[0005] For example, Chinese patent application CN101597497A discloses an acidic water glass grouting material. The above technical solution introduces organic esters such as triacetin as latent curing agents to delay the gelation time and provide a certain strength. However, after careful reading, it is found that the essence of the above technical solution is still based on the physical curing of silica gel. If it is soaked in groundwater for a long time or washed by flowing water, sodium ions in the gel skeleton are easily dissolved, causing the silica gel network to dehydrate, shrink and hydrolyze, ultimately causing the strength of the solidified body to decrease significantly or even collapse.

[0006] For example, Chinese patent application CN114704276A discloses a modified two-component grout for water-rich sand layers. To improve the water resistance and strength of the consolidated structure, it employs a cement-water glass two-component grouting process, hoping to improve grout performance by adding admixtures. However, after introducing cement particles, the grout essentially becomes a suspension with a particle size much larger than the diameter of fine sand, preventing it from penetrating micro-cracks or dense sand layers, thus losing the core advantage of injectability found in chemical grouts. Furthermore, research indicates that cement-water glass grouts are highly prone to segregation and stratification in underwater environments, with underwater consolidation strength only about 20% of its air strength, making it difficult to meet the reinforcement requirements of water-rich formations.

[0007] For example, Chinese patent application CN104558514A discloses a polyurethane-modified silicate grouting material. This technical solution utilizes hydrophilic polyurethane and water glass to form an interpenetrating network structure, significantly improving the material's toughness and water resistance. However, the polyurethane component is expensive, and isocyanates may cause excessive volume expansion upon contact with water, leading to ground disturbance. Furthermore, these organic-inorganic composite materials often have excessively high strength or toughness, easily causing mud cake formation or severe wear on the tunnel boring machine cutterhead, which does not meet the subsequent requirements for easy cutting during construction.

[0008] In conclusion, developing a modified silicate grout with true solution-level permeability, improved water glass water resistance, suitable strength, and easy excavation is of great significance for the temporary reinforcement of shield tunnels. Summary of the Invention

[0009] To address the deficiencies in the aforementioned technical solutions, the present invention aims to provide a modified silicate grouting material and its preparation method.

[0010] To achieve the above objectives, the present invention provides a modified silicate grouting material, which, by weight, comprises the following raw materials: A modified silicate grouting material, by weight, has the following raw material composition, including: component A and component B, wherein component A is 100 parts of industrial grade sodium silicate; The raw material composition of the 100 parts of component B is as follows: 40-60 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 5-15 parts of composite organic ester, 0.5-2 parts of silane coupling agent, 1-2.5 parts of nonionic surfactant, 1-3 parts of complexing agent, and the balance being deionized water.

[0011] Furthermore, the volume ratio of component A to component B is 1:1.

[0012] The industrial-grade sodium silicate in component A is an industrial-grade sodium silicate solution with a modulus of 2.4-3.3 and a Baume degree of 35-45°Bé, and a silica content of ≥26%. The composite organic ester is a homogeneous liquid formed by mixing triethanolamine glyceride and propylene glycol diacetate in a mass ratio of 1:1. The silane coupling agent is: γ-glycidoxypropyltrimethoxysilane or γ-methacryloxypropyltrimethoxysilane; The nonionic surfactant is Tween-80 or Tween-60; The complexing agent is citric acid monohydrate or tartaric acid.

[0013] The self-made silane-grafted polymerized aluminum phosphate modified solution was prepared by the following method: Step A: Silane pre-hydrolysis and activation: In a three-necked flask equipped with a reflux condenser, a constant temperature water bath, and a precision mechanical stirrer, add 100 mL of 95% ethanol aqueous solution; turn on the stirrer and control the speed at 200-300 rpm; add 2 g of γ-methacryloyloxypropyltrimethoxysilane; then add glacial acetic acid dropwise to precisely adjust the pH of the system to 4.0-5.0; at room temperature (25°C), turn on ultrasonic-assisted dispersion for 30 minutes until the solution changes from turbid to completely transparent, allowing the silane to be fully hydrolyzed to generate highly active silanol groups; Step B: Graft copolymerization reaction: Keep the solution stirred in Step A and increase the speed to 300-500 rpm; slowly add 50g of industrial-grade polyaluminum phosphate solution to the flask through a constant pressure dropping funnel, and complete the addition within 20-30 minutes; after the addition is complete, slowly heat the system to 60-80℃ and stir the reaction at a constant temperature for 4-6 hours. Step C: Solvent removal and post-treatment: After the reaction is completed, the reaction solution is transferred to a rotary evaporator; the water bath temperature is controlled at 50-60℃ and the vacuum degree is -0.08MPa, and vacuum distillation is carried out; most of the ethanol solvent is removed until the residual ethanol content is <5%; that is, a self-made silane-grafted polymerized aluminum phosphate modified solution with a slightly yellow, viscous, and semi-transparent luster is prepared.

[0014] Furthermore, the solid content of the industrial-grade polyaluminum phosphate solution in step B is ≥50%; A method for preparing a modified silicate grout includes the following steps: Component B is prepared using the following method: Step 1: In a dry stainless steel mixing tank, add the weighed composite organic ester and start low-speed stirring; then add the silane coupling agent and nonionic surfactant in sequence; stir at 25-30℃ for 5-10 minutes until a transparent and homogeneous organic oil phase solution is formed. Step 2: Then, in a jacketed cooling stirred tank, add deionized water and start stirring at medium speed (300-400 rpm); slowly add the complexing agent and stir until completely dissolved; Step 3: Then turn on the inline high-shear emulsifier and set the speed to 1500-2000 rpm; slowly inject the well-stirred organic oil phase solution prepared in Step 1 into the aqueous phase prepared in Step 2, and circulate and emulsify for 10 minutes to form an oil-in-water emulsion. Step 4: Slowly pour the prepared self-made silane-grafted polymerized aluminum phosphate modified liquid into the emulsion prepared in Step 3; reduce the stirring speed to 500 rpm and continue stirring for 15-20 minutes until a uniform and stable milky white or semi-transparent dispersion is formed, thus obtaining component B.

[0015] Furthermore, in the preparation method of the modified silicate grout, when in use, component A and the prepared component B are placed in the two hoppers of a dual-liquid grouting pump respectively; after being mixed by a Y-type mixer at a volume ratio of 1:1, they are injected into the formation; thus, a modified silicate grout is prepared.

[0016] The beneficial effects of this invention are: 1. This invention prepares a self-made silane-grafted polymerized aluminum phosphate modified liquid and introduces it into a water glass grouting system. By utilizing the pre-grafted hydrophobic long chains and high-strength aluminum phosphate inorganic framework on the silane-grafted polymerized aluminum phosphate molecular chain, a dense hydrophobic barrier is constructed inside the gel, effectively blocking the attack of water molecules on silicon-oxygen bonds and the dissolution channels of sodium ions. This greatly delays the problems of easy hydrolysis, shrinkage, and even disintegration of traditional water glass gels in a water environment, and significantly extends the service life of temporary reinforcement projects. 2. The technical solution of this application encapsulates a highly active modified curing agent, namely a self-made silane-grafted polymerized aluminum phosphate modified liquid and a composite organic ester, in a microemulsion micelle; this allows the grout to maintain an extremely low initial viscosity before injection, enabling it to penetrate into micro-cracks or fine sand layers; and at the moment the grout is injected into the formation and mixed with water glass, the emulsion breaks down, triggering a rapid cross-linking reaction, and the resulting hybrid network structure has extremely strong adhesion and erosion resistance. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. Furthermore, regarding numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0018] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0019] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0020] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0021] Example 1 A modified silicate grout, by weight, has the following raw material composition, including: component A and component B, wherein the mixing volume ratio of component A and component B is 1:1; Component A is 100 parts of industrial-grade sodium silicate; The raw material composition of component B is as follows: 50 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 10 parts of composite organic ester, 1.0 part of silane coupling agent, 2.0 parts of nonionic surfactant, 2.0 parts of complexing agent, and 35 parts of deionized water.

[0022] The industrial-grade sodium silicate is a liquid water glass with a modulus of 3.0 and a Baume degree of 40°Bé. The composite organic ester is a homogeneous liquid formed by mixing triethanolamine glyceride and propylene glycol diacetate in a mass ratio of 1:1. The silane coupling agent is: γ-glycidoxypropyltrimethoxysilane, with a purity ≥98%; The nonionic surfactant is Tween-80; The complexing agent is citric acid monohydrate.

[0023] The self-made silane-grafted polymerized aluminum phosphate modified solution was prepared by the following method: Step A: Silane pre-hydrolysis and activation: In a three-necked flask equipped with a reflux condenser, a constant temperature water bath, and a precision mechanical stirrer, add 100 mL of 95% ethanol aqueous solution; turn on the stirrer and control the speed at 200-300 rpm; add 2 g of γ-methacryloyloxypropyltrimethoxysilane; then add glacial acetic acid dropwise to precisely adjust the pH of the system to 4.0-5.0; at room temperature (25°C), turn on ultrasonic-assisted dispersion for 30 minutes until the solution changes from turbid to completely transparent, allowing the silane to be fully hydrolyzed to generate highly active silanol groups; Step B: Graft copolymerization reaction: Maintain the stirring state of the solution in Step A and increase the rotation speed to 300-500 rpm; slowly add 50g of industrial-grade polyaluminum phosphate solution to the flask through a constant pressure dropping funnel, controlling the addition time to be completed within 20-30 minutes; after the addition is completed, slowly raise the temperature of the system to 60-80℃ and stir the reaction at a constant temperature for 4-6 hours; during the reaction, the silanol groups generated by silane hydrolysis undergo a dehydration condensation reaction with the hydroxyl groups on the surface of the polyaluminum phosphate molecular chain to form stable Al-O-Si or PO-Si covalent bonds, thereby realizing the chemical grafting of organic hydrophobic segments onto the inorganic framework; Step C: Solvent removal and post-treatment: After the reaction is completed, the reaction solution is transferred to a rotary evaporator; the water bath temperature is controlled at 50-60℃ and the vacuum degree is -0.08MPa, and vacuum distillation is carried out; most of the ethanol solvent is removed until the residual ethanol content is <5%; that is, a self-made silane-grafted polymerized aluminum phosphate modified solution with a slightly yellow, viscous, and semi-transparent luster is prepared.

[0024] Furthermore, the solid content of the industrial-grade polyaluminum phosphate solution in step B is ≥50%.

[0025] A method for preparing a modified silicate grout includes the following steps: Component B is prepared using the following method: Step 1: In a dry stainless steel mixing tank, add the weighed composite organic ester and start low-speed stirring; then add the silane coupling agent and nonionic surfactant in sequence; stir at 25-30℃ for 5-10 minutes until a transparent and homogeneous organic oil phase solution is formed. Step 2: Then, in a jacketed cooling stirred tank, add deionized water, turn on the stirrer, and set the speed to 300-400 rpm; slowly add the complexing agent and stir until completely dissolved. Step 3: Then turn on the inline high-shear emulsifier and set the speed to 1500-2000 rpm; slowly inject the well-stirred organic oil phase solution prepared in Step 1 into the aqueous phase prepared in Step 2, and circulate and emulsify for 10 minutes to form an oil-in-water emulsion. Step 4: Slowly pour the prepared self-made silane-grafted polymerized aluminum phosphate modified liquid into the emulsion prepared in Step 3; reduce the stirring speed to 500 rpm and continue stirring for 15-20 minutes until a uniform and stable milky white or semi-transparent dispersion is formed, thus obtaining component B.

[0026] Furthermore, in the preparation method of the modified silicate grout, when in use, component A and the prepared component B are placed in the two hoppers of a dual-liquid grouting pump respectively; after being mixed by a Y-type mixer at a volume ratio of 1:1, they are injected into the formation; thus, a modified silicate grout is prepared.

[0027] Example 2 A modified silicate grout, by weight, has the following raw material composition, including: component A and component B, wherein the mixing volume ratio of component A and component B is 1:1; Component A is 100 parts of industrial-grade sodium silicate; The raw material composition of component B is as follows: 60 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 15 parts of composite organic ester, 2 parts of silane coupling agent, 2.5 parts of nonionic surfactant, 3.0 parts of complexing agent, and 17.5 parts of deionized water.

[0028] The industrial-grade sodium silicate in component A is an industrial-grade sodium silicate solution with a modulus of 2.4 and a Baume degree of 45°Bé, and a silica content of ≥26%. The silane coupling agent is: γ-glycidoxypropyltrimethoxysilane; The nonionic surfactant is Tween-80; The complexing agent is citric acid monohydrate; The preparation methods of the self-made silane-grafted polymerized aluminum phosphate modified liquid and the preparation method of the modified silicate grout in Example 2 are the same as those in Example 1.

[0029] Example 3 A modified silicate grout, by weight, has the following raw material composition, including: component A and component B, wherein the mixing volume ratio of component A and component B is 1:1; Component A is 100 parts of industrial-grade sodium silicate; The raw material composition of component B is as follows: 40 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 8 parts of composite organic ester, 0.5 parts of silane coupling agent, 1.5 parts of nonionic surfactant, 1 part of complexing agent, and 49 parts of deionized water.

[0030] The industrial-grade sodium silicate in component A is an industrial-grade sodium silicate solution with a modulus of 3.3 and a Baume degree of 35°Bé, and a silica content of ≥26%. The silane coupling agent is: γ-glycidoxypropyltrimethoxysilane; The nonionic surfactant is Tween-60; The complexing agent is tartaric acid; The preparation methods of the self-made silane-grafted polymerized aluminum phosphate modified liquid and the preparation method of the modified silicate grouting material in Example 3 are the same as those in Example 1.

[0031] Example 4 A modified silicate grout, by weight, has the following raw material composition, including: component A and component B, wherein the mixing volume ratio of component A and component B is 1:1; Component A is 100 parts of industrial-grade sodium silicate; The raw material composition of component B is as follows: 45 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 5 parts of composite organic ester, 0.8 parts of silane coupling agent, 1.0 part of nonionic surfactant, 1.5 parts of complexing agent, and 46.7 parts of deionized water.

[0032] The industrial-grade sodium silicate in component A is an industrial-grade sodium silicate solution with a modulus of 2.8 and a Baume degree of 42°Bé, and a silica content of ≥26%. The silane coupling agent is: γ-methacryloyloxypropyltrimethoxysilane; The nonionic surfactant is Tween-60; The complexing agent is citric acid monohydrate; The preparation methods of the self-made silane-grafted polymerized aluminum phosphate modified liquid and the preparation method of the modified silicate grouting material in Example 4 are the same as those in Example 1.

[0033] Example 5 A modified silicate grout, by weight, has the following raw material composition, including: component A and component B, wherein the mixing volume ratio of component A and component B is 1:1; Component A is 100 parts of industrial-grade sodium silicate; The raw material composition of component B is as follows: 55 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 12 parts of composite organic ester, 1.5 parts of silane coupling agent, 2.0 parts of nonionic surfactant, 2.5 parts of complexing agent, and 27 parts of deionized water.

[0034] The industrial-grade sodium silicate in component A is an industrial-grade sodium silicate solution with a modulus of 3.1 and a Baume degree of 38°Bé, and a silica content of ≥26%. The silane coupling agent is: γ-glycidoxypropyltrimethoxysilane; The nonionic surfactant is Tween-80; The complexing agent is tartaric acid; The preparation methods of the self-made silane-grafted polymerized aluminum phosphate modified liquid and the preparation method of the modified silicate grout in Example 5 are the same as those in Example 1.

[0035] Comparative Example 1 This comparative example is based on Example 1, but differs from Example 1 in that: in the preparation process of the self-made silane-grafted polyaluminum phosphate modified liquid, specifically, steps A and B are omitted, and equal amounts of industrial-grade polyaluminum phosphate solution and γ-methacryloyloxypropyltrimethoxysilane that has not undergone pre-hydrolysis treatment are directly added to the system in step 4 of the preparation process of component B of a modified silicate grout.

[0036] Apart from the above, the other components, their amounts, and preparation methods in this comparative example are the same as in Example 1.

[0037] Comparative Example 2 This comparative example is based on Example 1, but differs from Example 1 in that: the self-made silane-grafted polymerized aluminum phosphate modification liquid is replaced with a common acidic curing agent; specifically: in the formulation of component B, the self-made silane-grafted polymerized aluminum phosphate modification liquid is not used, but is replaced with an equal mass of industrial-grade polymerized aluminum phosphate solution. Apart from the above, the other components, their amounts, and preparation methods in this comparative example are the same as in Example 1.

[0038] Comparative Example 3 This comparative example is based on Example 1. The difference between this example and Example 1 is that: in the preparation process of component B of the modified silicate grout, steps 1, 2, and 3 are omitted. Instead, the composite organic ester, silane coupling agent, and surfactant are directly poured into a stirred tank containing a self-made silane-grafted polymerized aluminum phosphate modified liquid and a complexing agent. The mixture is then stirred at a low speed of about 300 rpm to achieve uniform mixing and obtain component B.

[0039] Apart from the above, the other components, their amounts, and preparation methods in this comparative example are the same as in Example 1.

[0040] Comparative Example 4 This comparative example is based on Example 1, but differs from Example 1 in that: the complexing agent in component B is omitted; specifically, in the formulation of component B, the complexing agent is removed, and the mass fraction removed is made up by deionized water; other preparation steps remain unchanged.

[0041] Apart from the above, the other components, their amounts, and preparation methods in this comparative example are the same as in Example 1.

[0042] Comparative Example 5 This comparative example is based on Example 1, but differs from Example 1 in that: in the preparation of the self-made silane-grafted polymerized aluminum phosphate modified liquid; specifically, in step A, glacial acetic acid is not added to adjust the pH value, and ultrasonic dispersion is carried out directly at the natural pH value; then the subsequent reaction in step B is carried out directly.

[0043] Apart from the above, the other components, their amounts, and preparation methods in this comparative example are the same as in Example 1.

[0044] Comparative Example 6 This comparative example is based on Example 1, but differs from Example 1 in that the silane coupling agent in component B is omitted; specifically, in step 1 of the preparation process of component B, no silane coupling agent is added.

[0045] Apart from the above, the other components, their amounts, and preparation methods in this comparative example are the same as in Example 1.

[0046] Test case Viscosity test: Referring to GB / T22235-2008 "Determination of viscosity of liquids", a digital rotational viscometer was used to measure the initial viscosity of Examples 1-5 and Comparative Examples 1-6 immediately after mixing at 25°C.

[0047] Compressive strength test: Refer to JGJ / T70-2009 "Standard for Test Methods of Basic Performance of Building Mortar"; use standard fine sand (particle size 0.075-0.25mm), and inject the mixed slurry into a mold (70.7mm×70.7mm×70.7mm) containing standard sand, allowing it to naturally penetrate and solidify; after the test blocks are cured under standard curing conditions for 3 days, 7 days and 28 days respectively, the unconfined compressive strength test is carried out using an electronic universal testing machine, with the loading rate set to 1-2mm / min, and the compressive strength after 3 days, 7 days and 28 days is measured.

[0048] Water-to-land curing strength ratio: According to the molding method of mortar test blocks in JGJ / T70-2009 "Standard for Test Methods of Basic Performance of Building Mortar", standard fine sand and slurry are mixed evenly at a volume ratio of 1:1, poured into the mold, and vibrated to compact; and all test blocks are placed in a standard curing room at a temperature of 20±2℃ and a relative humidity of ≥95% for 24 hours before demolding.

[0049] Subsequently, group curing was carried out: The underwater immersion curing group: the test blocks were completely submerged in static deionized water in a constant temperature water bath, with the water level at least 20mm above the top of the test blocks; the water temperature was set at 20±2℃, and after 28 consecutive days of curing, its compressive strength was tested, and the compressive strength after 28 days was recorded as R. 水下 In the onshore curing group: the test blocks were placed in a constant temperature and humidity curing chamber, with the temperature set at 20±2℃ and the relative humidity at ≥95%, and cured continuously for 28 days. Their compressive strength was then tested, and the compressive strength after 28 days was recorded as R. 陆地 Calculate the water-land intensity ratio = (R 水下 / R 陆地 )*100%.

[0050] Water erosion simulation test: Similar to the compressive strength test, test blocks of Examples 1-5 and Comparative Examples 1-6 were prepared. Then, all test blocks were cured in a standard curing room at a temperature of 20±2℃ and a relative humidity of ≥95% for 28 days. Then, an initial drying treatment was carried out: the cured test blocks were placed in an electric heating drying oven at 60±5℃ and dried to constant weight, and their initial dry weight M0 was recorded. The dried specimen was then fixed to the sample rack at the bottom of the water tank of the circulating water rinsing device, ensuring that the water flow direction was parallel to one side of the specimen. During the rinsing process, the water pump was started and the valve was adjusted to keep the average flow velocity through the specimen cross-section in the water tank stable at 0.4 m / s, and the water temperature was kept at 20±2℃. After rinsing continuously for 72 hours, carefully remove the test block and then put it back into an electric heating drying oven at 60±5℃ to dry to constant weight. Record its final dry weight M1. Calculate the mass loss rate = [(M0-M1) / M0]*100%.

[0051] The test results are shown in Table 1: Table 1 As shown in Table 1, the modified silicate grouts prepared in Examples 1-5 of this invention exhibit excellent performance in all performance tests. Taking Example 1 as an example, while maintaining an extremely low initial viscosity of 6.5 mPa·s, its 28-day water-to-land strength ratio is as high as 95.8%, indicating minimal impact from water erosion. Furthermore, in the 72-hour dynamic water scouring test, the mass loss rate is only 1.15%, and the structure remains intact without peeling. This demonstrates that the materials in Examples 1-5 possess excellent erosion resistance. The underlying reason is that the technical solution of this application, through the preparation of a self-made silane-grafted polymerized aluminum phosphate modified liquid and its introduction into the water glass grouting system, utilizes the pre-grafted hydrophobic long chains and high-strength aluminum phosphate inorganic framework on the silane-grafted polymerized aluminum phosphate molecular chain to construct a dense hydrophobic barrier within the gel, effectively blocking the attack of water molecules on silicon-oxygen bonds and the dissolution channels of sodium ions.

[0052] None of the properties of Comparative Example 4 could be measured because the complexing agent was omitted in Comparative Example 4, which caused the slurry to solidify in less than 1 minute after mixing. Therefore, the subsequent performance test data could not be obtained. This shows that the technical solution of this application effectively delayed the violent reaction between component A and component B by introducing a complexing agent and establishing a sacrificial layer, so that there was enough time for construction.

[0053] Although Comparative Example 2 had a low initial viscosity, its water-to-land strength ratio was only 32.5%, and its mass loss rate was as high as 55.8%. These characteristics are typical of soft gels: rapid skeletal hydrolysis and dissolution in water, making it unsuitable for long-term or dynamic water environments requiring reinforcement. This indirectly illustrates that simply neutralizing water glass with inorganic acids cannot fundamentally improve its water resistance; rather, it is necessary to introduce a hydrophobic framework with chemical bonding capabilities for modification.

[0054] Although Comparative Example 1 has the exact same formulation as Example 1, its water-to-land strength ratio decreased significantly to 62.4% and its dynamic water loss rate increased to 15.2% due to the use of a "physical mixing" process instead of a "chemical grafting" process. This indicates that simply mixing silane, polyaluminum phosphate, and water glass can easily cause silane to self-polymerize or float in the system, making it impossible to effectively graft onto the inorganic framework to form a protective layer. In contrast, the technical solution of this application, through specific preparation methods and processes, ensures that hydrophobic groups can be uniformly anchored on the framework, thereby playing a role over a longer time span.

[0055] For Comparative Example 5, the initial viscosity was high, reaching 18.2 mPa·s, with a water-to-land strength ratio of only 68.5% and a dynamic water mass loss rate of 12.4%. This may be because, in step A of preparing the self-made silane-grafted polyaluminum phosphate modified solution, Comparative Example 5 omitted the use of glacial acetic acid for pH adjustment. The hydrolysis of γ-methacryloyloxypropyltrimethoxysilane is extremely sensitive to pH; without pH adjustment, the hydrolysis rate of silane is extremely slow and incomplete, resulting in a severely insufficient concentration of generated active silanol groups. This directly caused the failure of the subsequent grafting reaction: a large amount of silane failed to be chemically anchored to the polyaluminum phosphate backbone, instead existing in free or oligomer forms.

[0056] The ungrafted polyaluminum phosphate skeleton still has strong hydrophilicity and is prone to hydrolysis and dissolution in underwater environments, resulting in a low water-to-land strength ratio. Furthermore, the free silane self-polymer increases the viscosity of the system (18.2 mPa·s) and cannot form effective cross-linking points in the gel network, making the solidified structure loose and reducing its resistance to water erosion.

[0057] Comparative Example 3 omitted steps 1, 2, and 3 of the preparation process, resulting in slurry stratification, an increase in viscosity to 35.0 mPa·s, and subsequent water-to-land strength ratio and mass loss rate failing to achieve the technical effects of Example 1 of this application. This fully demonstrates that only through the preparation process and method of this application can the various active components of component B be encapsulated, thereby achieving uniformity and stability of the slurry.

[0058] Comparative Example 6, which removed the silane coupling agent, showed a decent water-to-land strength ratio, approaching 80%, but its mass loss rate was as high as 8.65%, significantly higher than that of Example 1. The possible reason is that the additional free silane coupling agent migrated to the interface between the solidified body and the formation during gel solidification, enhancing interfacial adhesion and effectively preventing water erosion and peeling along the edges.

[0059] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modified silicate grout, characterized in that, By weight, its composition is as follows, including: component A and component B; Component A is 100 parts of industrial grade sodium silicate; The raw material composition of the 100 parts of component B is as follows: 40-60 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 5-15 parts of composite organic ester, 0.5-2 parts of silane coupling agent, 1-2.5 parts of nonionic surfactant, 1-3 parts of complexing agent, and the balance being deionized water.

2. The modified silicate grouting material according to claim 1, characterized in that, The modified silicate grouting material comprises: component A and component B; Component A is 100 parts of industrial-grade sodium silicate; The raw material composition of component B is as follows: 50 parts of self-made silane-grafted polymerized aluminum phosphate modified liquid, 10 parts of composite organic ester, 1.0 part of silane coupling agent, 2.0 parts of nonionic surfactant, 2.0 parts of complexing agent, and 35 parts of deionized water. The volume ratio of component A to component B is 1:

1.

3. The modified silicate grouting material according to claim 1, characterized in that, The industrial-grade sodium silicate in component A is an industrial-grade sodium silicate solution with a modulus of 2.4-3.3 and a Baume degree of 35-45°Bé, and a silica content of ≥26%.

4. The modified silicate grouting material according to claim 1, characterized in that, The composite organic ester is a homogeneous liquid formed by mixing triethanolamine glyceride and propylene glycol diacetate in a mass ratio of 1:

1.

5. The modified silicate grouting material according to claim 1, characterized in that, The silane coupling agent is: γ-glycidoxypropyltrimethoxysilane or γ-methacryloxypropyltrimethoxysilane.

6. The modified silicate grouting material according to claim 1, characterized in that, The nonionic surfactant is Tween-80 or Tween-60.

7. The modified silicate grouting material according to claim 1, characterized in that, The complexing agent is citric acid monohydrate or tartaric acid.

8. The modified silicate grouting material according to claim 1, characterized in that, The self-made silane-grafted polymerized aluminum phosphate modified solution was prepared by the following method: Step A: Silane pre-hydrolysis and activation: Add 95% ethanol aqueous solution to a three-necked flask; start stirring; add γ-methacryloyloxypropyltrimethoxysilane; then add glacial acetic acid dropwise to adjust the pH of the system to 4.0-5.0; and perform ultrasonic-assisted dispersion at room temperature (25°C) for 30 minutes. Step B: Graft copolymerization reaction: Keep the solution stirred in Step A; slowly add industrial-grade polyaluminum phosphate solution dropwise to the flask through a constant pressure dropping funnel, and complete the addition within 20-30 minutes; after the addition is complete, slowly heat the system to 60-80℃ and stir the reaction at a constant temperature for 4-6 hours. Step C: Solvent removal and post-treatment: After the reaction is completed, the reaction solution is transferred to a rotary evaporator for vacuum distillation; thus, the self-made silane-grafted polymerized aluminum phosphate modified solution is prepared.

9. A modified silicate grouting material according to any one of claims 1-8, characterized in that, Component B is prepared by the following method: Step 1: In the mixing tank, add the compound organic ester and start low-speed stirring; then add the silane coupling agent and nonionic surfactant in sequence; stir at 25-30℃ for 5-10 minutes until a transparent and homogeneous organic oil phase solution is formed; Step 2: Then, in a jacketed cooling stirred tank, add deionized water and start stirring; slowly add the complexing agent and stir until completely dissolved; Step 3: Then turn on the inline high-shear emulsifier and set the speed to 1500-2000 rpm; slowly inject the well-stirred organic oil phase solution prepared in Step 1 into the aqueous phase prepared in Step 2, and circulate and emulsify for 10 minutes to form an oil-in-water emulsion. Step 4: Slowly pour the prepared self-made silane-grafted polymerized aluminum phosphate modified liquid into the emulsion prepared in Step 3; reduce the stirring speed to 500 rpm and continue stirring for 15-20 minutes until a uniform and stable milky white or semi-transparent dispersion is formed, thus obtaining component B.

10. A method for preparing a modified silicate grouting material according to any one of claims 1-8, characterized in that, The method for preparing the modified silicate grout involves placing component A and the prepared component B into the two hoppers of a dual-liquid grouting pump during use. The modified silicate grout is prepared by mixing the materials in a 1:1 volume ratio using a Y-type mixer and then injecting them into the formation.

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