High-strength pumpable anchoring agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of geotechnical engineering reinforcing materials, in particular to a high-strength pumpable anchoring agent and a preparation method and application thereof. The anchoring agent is composed of a component A and a component B, wherein the component A comprises 60-80 parts of a first sodium silicate solution, 20-40 parts of a second sodium silicate solution, 2-8 parts of a catalyst, 5-20 parts of a chain extender, 1-5 parts of a thixotropic agent and 0.5-2 parts of a reinforcing agent; the component B comprises the following components in parts by weight: 90-110 parts of isocyanate substances, 10-30 parts of a plasticizer and 2-6 parts of polyether polyol. According to the preparation method, a one-step mechanical blending process is adopted, and the component A and the component B are respectively mixed, stirred and defoamed. Through synergistic compounding of specific components, a traditional complex pre-polymerization process is abandoned, and the obtained anchoring agent has the advantages of being simple in preparation process, controllable in curing time, high in compressive strength, good in pumpability, environmentally friendly, safe and the like, and is particularly suitable for rock-soil anchoring of underground engineering such as coal mines and tunnels.

Description

Technical Field

[0001] This invention relates to the field of engineering reinforcement materials technology, and in particular to a high-strength pumpable anchoring agent, its preparation method, and its application. Background Technology

[0002] In underground engineering projects such as coal mine shaft support and tunnel surrounding rock reinforcement, the performance of anchoring agents has a decisive impact on support safety and project durability. Currently widely used anchoring materials, such as cement-based anchoring agents and resin anchoring agents, all have significant defects.

[0003] Traditional anchoring agents, represented by cement-based ones, have been described in CN201711321405.5 as a super-strong composite material. While this material offers cost advantages, it suffers from slow curing speed and low early strength, making it unsuitable for dynamic mining pressure environments. Resin anchoring agents have high viscosity, poor flowability, and poor pumpability, hindering mechanization and automation and failing to meet the demands of rapid coal mine excavation. Although organic anchoring agents exhibit excellent mechanical properties, their strength is reduced due to intense exothermic reactions and foaming, limiting their application under high-stress geological conditions.

[0004] Some existing water glass modified polyurethane systems attempt to combine the advantages of inorganic and organic materials, but still have obvious shortcomings: some formulations (such as CN202210026813.2) require complex prepolymerization processes, the material properties are extremely sensitive to the composition ratio, the curing time adjustment is not flexible enough, and it is difficult to meet the requirements of rapid construction under diverse geological conditions.

[0005] In addition, some formulations have certain safety risks and environmental issues in the selection of raw materials. For example, CN202310857459.2 uses small molecule isocyanates with high vapor pressure, which poses a significant safety hazard, especially in underground closed environments. CN201210518231.2 uses organotin catalysts, which do not meet environmental protection requirements. At the same time, the solidified bodies of most systems lack synergistic enhancement between compressive and shear strength, and due to insufficient thixotropy or excessive viscosity, they have poor pumpability and are difficult to adapt to the long-distance transportation requirements of high-pressure grouting equipment.

[0006] Therefore, developing an environmentally friendly anchoring agent with simple preparation process, controllable curing time, excellent mechanical properties, and excellent pumpability has become an urgent technical problem to be solved in this field. Summary of the Invention

[0007] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a high-strength pumpable anchoring agent, its preparation method, and its application. This anchoring agent, through specific component design and simplified processes, achieves multiple advantages such as high strength, excellent pumpability, rapid curing, and environmental safety.

[0008] The technical solution adopted by this invention to solve its technical problem is: A high-strength pumpable anchoring agent, characterized in that it is composed of component A and component B, and is mixed in a volume ratio of 1:1 when used; The A component, by mass, comprises: 60-80 parts of a first sodium silicate solution, 20-40 parts of a second sodium silicate solution, 2-8 parts of a catalyst, 5-20 parts of a chain extender, 1-5 parts of a thixotropic agent, and 0.5-2 parts of a reinforcing agent. Component B, by mass, comprises: 90-110 parts isocyanate, 10-30 parts plasticizer, and 2-6 parts polyether polyol.

[0009] The mechanism of action of this invention is analyzed as follows: Component A and component B are mixed and reacted in a 1:1 volume ratio. Under the action of a catalyst, firstly, water in component A reacts with isocyanate in component B to generate amine and release carbon dioxide. It is worth noting that the generated carbon dioxide does not directly escape from the system to trigger conventional foaming and expansion, but is captured and absorbed by sodium silicate in the system, and converted into inorganic salts such as silicic acid and sodium carbonate. Figure 1 (a) shows a porous structure, which is a remnant of carbon dioxide release, and the particles inside the pores are condensed products of precipitated inorganic salts. Secondly, as the reaction proceeds, the rising system temperature further activates the catalyst, significantly accelerating the gelation reaction of isocyanate with polyols and amines, generating urethane and urea, promoting the rapid formation of a three-dimensional polyurethane network, thereby endowing the anchoring system with high strength properties. For example... Figure 1 As shown in (b), the continuous phase is a polyurethane structure, and its thickness is positively correlated with the compressive strength of the anchoring system. Furthermore, it should be noted that the isocyanate can react with the generated silicic acid, introducing Si-O bonds into the polyurethane macromolecular backbone; simultaneously, the unstable silicic acid molecules can further dehydrate and condense to form a silica network; sodium carbonate precipitates in crystalline form, intercalating between the organic and inorganic networks, ultimately forming a multiphase interpenetrating organic-inorganic network structure. This unique structure, through interfacial interactions and component synergistic effects, jointly endows the anchoring agent consolidation body with excellent mechanical strength and toughness.

[0010] Further, the first sodium silicate solution is a sodium silicate solution with a modulus of 2.1 to 2.8 and a Baume degree of 45 to 51°Bé; the second sodium silicate solution is a sodium silicate solution with a modulus of 2.8 to 3.5 and a Baume degree of 40 to 45°Bé.

[0011] Furthermore, the mass ratio of the first sodium silicate solution to the second sodium silicate solution is 7:3.

[0012] The selected sodium silicate solution is a mixture of solutions with different Baumé degrees and moduli. Baumé degree and modulus are important properties of sodium silicate solutions. The higher the modulus, the higher the silicon content and the stronger the adhesive force, but it will also be more difficult to dissolve in water. Therefore, it is important to select an appropriate range of moduli. Baumé degree indicates the concentration of the solution; the higher the concentration, the more sodium silicate and silicate it contains. By mixing sodium silicate solutions with different Baumé degrees and moduli, the viscosity of component A can be controlled, resulting in a final anchoring agent with good solubility and adhesive force.

[0013] Further, in component A, the catalyst is selected from a complex system of tertiary amine catalysts and carboxylates, wherein the tertiary amine catalyst is selected from one or more of N,N-dimethylbenzylamine, N,N-dimethylcyclohexylamine, tetramethyl-1,6-hexanediamine, triethylenediamine, dimethylaminoethoxyethanol, and tetramethyldipropylenetriamine; the carboxylate is selected from one or more of potassium acetate, potassium oleate, and potassium octanoate; the chain extender is selected from one or more of glycerol, isophorone diamine, and methylallylpropanediamine; the reinforcing agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, carbodiimide, and 1,10-diaminodecane; and the thixotropic agent is selected from one or more of fumed silica, precipitated silica, silane-modified silica, organobentonite, and hydrogenated castor oil.

[0014] Catalysts (such as tertiary amine catalysts combined with carboxylates) offer high catalytic efficiency and are environmentally friendly and non-toxic, avoiding the environmental pollution problems of traditional organotin catalysts and improving product safety and environmental friendliness. Chain extenders (such as glycerol) can effectively participate in and regulate the polymerization reaction network, enhance crosslinking density, and improve the strength and toughness of the cured body.

[0015] Thixotropic agents impart excellent thixotropic properties to the slurry, meaning it is thick at rest and thin under shear. This allows the anchoring agent to have good fluidity during pumping, and it can quickly recover its viscosity after being injected into rock fissures, preventing flow and ensuring the anchoring effect. This is the key to achieving "pumpability".

[0016] The sodium silicate solution in component A is a compound solution with different moduli, which can effectively reduce the viscosity of component A and regulate its solubility and binding force.

[0017] The catalyst in component A is a complex system of a tertiary amine catalyst and a carboxylate. During mixing, an acid-base reaction occurs, generating in situ a quaternary ammonium carboxylate salt with higher catalytic activity, which significantly enhances the catalytic efficiency of the subsequent gelation reaction. In the initial stage of the reaction, the tertiary amine catalyst and the newly generated quaternary ammonium cations effectively activate water molecules, promoting the reaction between water and isocyanate. At this time, the carboxylate has low activity and limited catalytic effect on the gelation reaction, thus effectively delaying the increase in system viscosity and ensuring that the anchoring agent maintains good fluidity and permeability in the early stages of construction. As the reaction progresses to the middle and later stages, the increase in system temperature significantly activates the catalytic activity of carboxylate ions, accelerating the gelation reaction between isocyanate and polyols and amines, promoting rapid gelation of the system and the formation of a highly cross-linked three-dimensional network structure, thereby achieving rapid curing and significantly improving the mechanical properties of the anchoring agent.

[0018] The reinforcing agent in component A is a small molecule containing bifunctional groups, which can effectively improve the interfacial interaction between inorganic and organic substances and enhance the mechanical strength of the anchoring agent system.

[0019] Furthermore, the mechanical properties of the anchoring agent system are closely related to its crosslinking density. By controlling the type and amount of chain extender in component A, and the molecular structure and content of polyether polyol in component B, the crosslinking structure can be controlled, thereby optimizing the mechanical properties of the anchoring agent. In addition, the polyether polyol in component B can also regulate the toughness of the anchoring agent, enabling it to maintain high strength while retaining high toughness. High-strength, high-toughness anchoring agents provide a safe and reliable guarantee for complex geotechnical anchoring projects.

[0020] Further, in component B, the isocyanate is selected from one or more of diphenylmethane diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, trimer isocyanate, and polymethyl polyphenyl polyisocyanate; the plasticizer is selected from one or more of diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, dioctyl phthalate, and tributyl citrate.

[0021] Isocyanates with high functionality, such as polymethyl polyphenyl polyisocyanates, are preferred. These have low vapor pressure and low toxicity, significantly improving construction safety. They also form a dense three-dimensional network structure, contributing high strength and stability. Using the aforementioned plasticizer effectively reduces the viscosity of component B, improves its miscibility with component A, and adjusts the flexibility of the cured product, preventing brittle fracture.

[0022] A method for preparing the high-strength pumpable anchoring agent as described above specifically includes the following steps: Step S1: Prepare sodium silicate solution: Weigh the first sodium silicate solution and the second sodium silicate solution according to the ratio, and mix them evenly to obtain a sodium silicate solution; Step S2: Preparation of component A: Weigh out the chain extender, catalyst, reinforcing agent and thixotropic agent according to the ratio, mix them evenly to obtain a mixture, add the sodium silicate solution prepared in step S1 to the mixture, stir evenly and then degas to obtain component A. Step S3: Preparation of Component B: Weigh the isocyanate, plasticizer and polyether polyol according to the ratio, stir evenly and then degas to obtain Component B.

[0023] This invention abandons the complex multi-step prepolymerization process of traditional polyurethane anchoring agents and adopts a "one-step" mechanical blending process, which is simple, stable, and easy to industrialize.

[0024] Anchoring agent application: After mixing components A and B evenly in the specified proportions, use a pumping device to deliver the mixture to the required anchoring location.

[0025] Furthermore, in step S2, the mixing conditions for the chain extender, catalyst, reinforcing agent, and thixotropic agent are: a stirring speed of 300 rpm / min and a stirring time of 20 min; the mixing conditions for the mixture and the sodium silicate solution are: a stirring speed of 600 rpm / min and a stirring time of 30 min.

[0026] Furthermore, in step S3, the mixing conditions for isocyanate, plasticizer and polyether polyol are: stirring speed of 300 rpm / min and stirring time of 30 min.

[0027] The above process parameters ensure that the components are fully and evenly mixed, while avoiding the introduction of too many air bubbles or localized gelation due to excessively fast or slow shearing, thus guaranteeing the consistency and stability of the final product's performance.

[0028] Furthermore, in steps S2 and S3, the degassing process is one of vacuum centrifugal degassing, ultrasonic degassing, or static degassing. The specific operation of vacuum centrifugation degassing is as follows: the vacuum centrifugation degassing time is 1 to 5 minutes, and the vacuum degree is -0.1 MPa; The ultrasonic degassing time is 30–60 min; the static degassing time is 12–24 h.

[0029] Degassing treatment significantly reduces the air bubble content in the anchoring agent, resulting in a denser, less defective cured anchor structure, directly improving its compressive strength and durability. The availability of multiple degassing options also increases the flexibility and adaptability of the process.

[0030] An application of the high-strength pumpable anchoring agent as described above, wherein the anchoring agent is used in coal mine shaft support, tunnel surrounding rock reinforcement, or rock and soil anchoring in water conservancy and hydropower projects.

[0031] The beneficial effects of this invention are as follows: This invention is rationally designed and has the following advantages: (1) The high-strength pumpable anchoring agent provided by the present invention has good fluidity and adhesion, which can effectively enhance the bond between the anchor rod and the surrounding rock and significantly improve the mechanical strength of the anchor body. The cured strength of the material can reach more than 60MPa, and the anchor body has high compressive strength and good toughness, which can meet most engineering requirements and is very suitable for rock geological anchoring with high requirements; (2) The high-strength pumpable anchoring agent provided by the present invention has an adjustable setting time. The reaction rate can be easily adjusted by controlling the amount of catalyst, thereby preparing fast, medium and slow thixotropic anchoring agents with different setting times; the fastest can reach initial setting in about 20 seconds; according to the requirements of pumping construction process, the material curing time can be controlled in 2 to 3 minutes. (3) The high-strength pumpable anchoring agent provided by the present invention has a low reaction temperature and can react even under low temperature conditions, thus avoiding the safety hazards caused by high temperature; at the same time, it does not contain organic flame retardant components, has low VOCs (volatile organic compounds), and is an environmentally friendly material. After being injected into the stratum, it will not have a negative impact on the surrounding environment and meets the green environmental protection standards. (4) The high-strength pumpable anchoring agent provided by the present invention has stable performance, good pumpability, and wide application range. It can be widely used in various fields of rock and soil reinforcement such as coal seam geological support, underground engineering construction, and subway tunnel anchoring. (5) The high-strength pumpable anchoring agent preparation method provided by the present invention is simple and easy to operate. The raw materials used are simple and do not require prepolymerization treatment, thereby reducing production costs and energy consumption. In addition, TDI (toluene diisocyanate) is not used in the raw materials of the formula, which avoids the instability risks caused by its volatility, high reactivity and potential toxicity, and the performance is more stable during storage and use; (6) The high-strength pumpable anchoring agent A and B components provided by the present invention do not react with water during the mixing reaction process, and can quickly solidify underwater, with little impact on strength, and can reinforce rock mass in a watery environment. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Figure 1These are microscopic morphology images of the anchoring agent obtained in Example 1 at different magnification ratios, where a is 5.5mm × 350UD and b is 5.5mm × 3.0 K UD; Figure 2 These are the 24-hour compressive strength test curves of the anchoring agents obtained in Examples 1 to 3; Figure 3 This is a diagram showing the underwater curing process of the anchoring agent obtained in Example 1; Figure 4 This is a diagram of the pumping process of the anchoring agent obtained in Example 1. Detailed Implementation

[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In a first aspect, the present invention provides a high-strength pumpable anchoring agent, which is composed of component A and component B, and is mixed in a volume ratio of 1:1 when used. Component A, by mass, includes: 60-80 parts of first sodium silicate solution, 20-40 parts of second sodium silicate solution, 2-8 parts of catalyst, 5-20 parts of chain extender, 1-5 parts of thixotropic agent, and 0.5-2 parts of reinforcing agent. Component B, by weight, includes: 90-110 parts isocyanate, 10-30 parts plasticizer, and 2-6 parts polyether polyol.

[0039] The first sodium silicate solution is a sodium silicate solution with a modulus of 2.1 to 2.8 and a Baume degree of 45 to 51°Bé. The second sodium silicate solution is a sodium silicate solution with a modulus of 2.8 to 3.5 and a Baume degree of 40 to 45°Bé.

[0040] The mass ratio of the first sodium silicate solution to the second sodium silicate solution is 7:3. This specific mass ratio was determined based on extensive experiments, enabling the two sodium silicate solutions to work synergistically in the anchoring agent, balancing the early and later strength development of the anchoring agent, while ensuring good fluidity and pumpability, thus improving the overall performance of the anchoring agent.

[0041] In component A, the catalyst is selected from a complex system of tertiary amine catalysts and carboxylates. The tertiary amine catalyst is selected from one or more of N,N-dimethylbenzylamine, N,N-dimethylcyclohexylamine, tetramethyl-1,6-hexanediamine, triethylenediamine, dimethylaminoethoxyethanol, and tetramethyldipropylenetriamine. The carboxylate is selected from one or more of potassium acetate, potassium oleate, and potassium octanoate. The chain extender is selected from one or more of glycerol, isophorone diamine, and methylallylpropanediamine. The reinforcing agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, carbodiimide, and 1,10-diaminodecane. The thixotropic agent is selected from one or more of fumed silica, precipitated silica, silane-modified silica, organobentonite, and hydrogenated castor oil.

[0042] In component B, the isocyanate is selected from one or more of diphenylmethane diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, trimer isocyanate, and polymethyl polyphenyl polyisocyanate. The plasticizer is selected from one or more of diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, dioctyl phthalate, and tributyl citrate. The polyether polyol is selected from one or more of DL1000D, DL2000D, and silane-modified polyether polyol.

[0043] Secondly, the present invention provides a method for preparing the above-mentioned high-strength pumpable anchoring agent, specifically including the following steps: Step S1: Prepare sodium silicate solution: Weigh the first sodium silicate solution and the second sodium silicate solution according to the ratio, and mix them evenly to obtain a sodium silicate solution; Step S2: Preparation of component A: Weigh out the chain extender, catalyst, reinforcing agent and thixotropic agent according to the ratio, mix them evenly to obtain a mixture, add the sodium silicate solution prepared in step S1 to the mixture, stir evenly and then degas to obtain component A. Step S3: Preparation of Component B: Weigh the isocyanate, plasticizer and polyether polyol according to the ratio, stir evenly and then degas to obtain Component B.

[0044] In step S2, the mixing conditions for the chain extender, catalyst, reinforcing agent and thixotropic agent are: stirring speed of 300 rpm / min and stirring time of 20 min; the mixing conditions for the mixture and sodium silicate solution are: stirring speed of 600 rpm / min and stirring time of 30 min.

[0045] In step S3, the mixing conditions for isocyanate, plasticizer and polyether polyol are: stirring speed of 300 rpm / min and stirring time of 30 min.

[0046] In steps S2 and S3, the degassing process is one of vacuum centrifugation degassing, ultrasonic degassing, or static degassing. Specifically, the vacuum centrifugation degassing operation is as follows: the vacuum centrifugation degassing time is 1 to 5 minutes and the vacuum degree is -0.1 MPa; the ultrasonic degassing time is 30 to 60 minutes; and the static degassing time is 12 to 24 hours.

[0047] Degassing treatment can effectively remove air bubbles generated during the preparation of anchoring agents, avoiding the adverse effects of air bubbles on the strength and durability of anchoring agents, and improving the quality and performance of anchoring agents.

[0048] Thirdly, the present invention provides the application of the above-mentioned high-strength pumpable anchoring agent, which is used in coal mine shaft support, tunnel surrounding rock reinforcement or rock and soil anchoring in water conservancy and hydropower projects.

[0049] Example 1 The high-strength pumpable anchoring agent of this embodiment is composed of component A and component B, which are mixed at a volume ratio of 1:1 when used. Component A: 100 parts sodium silicate solution, 12 parts glycerol, 1 part hydrogenated castor oil, 4 parts catalyst (N,N-dimethylcyclohexylamine to potassium oleate mass ratio 1:6), 1 part γ-aminopropyltriethoxysilane. Component B: 100 parts of polymethyl polyphenyl polyisocyanate, 10 parts of diethylene glycol butyl ether acetate, and 5 parts of polyether polyol DL2000D.

[0050] The preparation method of the above-mentioned high-strength pumpable anchoring agent specifically includes the following steps: Step S1: Prepare sodium silicate solution: Weigh the first sodium silicate solution and the second sodium silicate solution at a mass ratio of 7:3, and mix them evenly to obtain the sodium silicate solution. Step S2: Preparation of component A: Take 12 parts of glycerol, 4 parts of catalyst, 1 part of hydrogenated castor oil, and 1 part of γ-aminopropyltriethoxysilane and add them to a mixer in sequence. Stir at 300 rpm / min for 15 min. Then add 100 parts of pre-mixed sodium silicate solution and stir at 600 rpm / min for 30 min. Degas under vacuum for 3 min to obtain component A. Step S3: Preparation of component B: Take 100 parts of polymethyl polyphenyl polyisocyanate, 10 parts of diethylene glycol butyl ether acetate and 5 parts of polyether polyol and add them to a mixer in sequence. Stir at 300 rpm / min for 30 min and then degas under vacuum for 3 min to obtain component B.

[0051] Figure 1 These are microstructure images of the anchoring agent obtained in Example 1 at different magnification ratios, where a is 5.5 mm × 350 UD and b is 5.5 mm × 3.0 K UD. Figure 1 It can be seen that the anchoring agent prepared in this embodiment is a multiphase interpenetrating organic-inorganic network structure. The microstructure shows that the anchoring system has a porous structure, which is the residue of carbon dioxide release. The particles inside the pores are the condensed products of precipitated inorganic salts, and the continuous phase around the pores is a polyurethane organic phase. Specifically, Figure 1 (a) shows a porous structure, which is a remnant of carbon dioxide release, and the particles inside the pores are condensed products of precipitated inorganic salts. Secondly, as the reaction proceeds, the rising system temperature further activates the catalyst, significantly accelerating the gelation reaction of isocyanate with polyols and amines, generating urethane and urea, promoting the rapid formation of a three-dimensional polyurethane network, thereby endowing the anchoring system with high strength properties. For example... Figure 1 As shown in (b), the continuous phase is a polyurethane structure, and its thickness is positively correlated with the compressive strength of the anchoring system.

[0052] Figure 4 This is a diagram showing the pumping process of the anchoring agent obtained in Example 1. The diagram shows that the mixed anchoring material has low viscosity and good fluidity, fully meeting the requirements of the pumping process.

[0053] Example 2 The high-strength pumpable anchoring agent of this embodiment is composed of component A and component B, which are mixed at a volume ratio of 1:1 when used. Component A: 110 parts sodium silicate solution, 5 parts glycerol, 3 parts hydrogenated castor oil, 2 parts catalyst (N,N-dimethylcyclohexylamine to potassium acetate mass ratio 1:10), 0.5 parts γ-aminopropyltriethoxysilane; Component B: 110 parts of polymethyl polyphenyl polyisocyanate, 10 parts of diethylene glycol butyl ether acetate, and 5 parts of polyether polyol DL2000D.

[0054] The preparation method of the above-mentioned high-strength pumpable anchoring agent specifically includes the following steps: Step S1: Prepare sodium silicate solution: Weigh the first sodium silicate solution and the second sodium silicate solution at a mass ratio of 7:3, and mix them evenly to obtain the sodium silicate solution. Step S2: Preparation of component A: Take 5 parts of glycerol, 4 parts of catalyst, 3 parts of hydrogenated castor oil and 0.5 parts of γ-aminopropyltriethoxysilane and add them to a mixer in sequence. Stir at 200 rpm / min for 20 min. Then add 110 parts of pre-mixed sodium silicate solution and stir at 1000 rpm / min for 15 min. Degas under vacuum for 3 min to obtain component A. Step S3: Preparation of component B: Take 110 parts of polymethyl polyphenyl polyisocyanate, 20 parts of diethylene glycol butyl ether acetate and 5 parts of polyether polyol and add them to a mixer in sequence. Stir at 500 rpm / min for 10 min and then degas under vacuum for 3 min to obtain component B.

[0055] Example 3 The high-strength pumpable anchoring agent of this embodiment is composed of component A and component B, which are mixed at a volume ratio of 1:1 when used. Component A: 100 parts sodium silicate solution, 18 parts glycerol, 5 parts hydrogenated castor oil, 5 parts catalyst (dimethylaminoethoxyethanol to potassium oleate in a mass ratio of 1:8), and 1.5 parts carbodiimide. Component B: 100 parts of polymethyl polyphenyl polyisocyanate, 10 parts of diethylene glycol butyl ether acetate, and 10 parts of polyether polyol DL2000D.

[0056] The preparation method of the above-mentioned high-strength pumpable anchoring agent specifically includes the following steps: Step S1: Prepare sodium silicate solution: Weigh the first sodium silicate solution and the second sodium silicate solution at a mass ratio of 7:3, and mix them evenly to obtain the sodium silicate solution. Step S2: Preparation of component A: Take 18 parts of glycerol, 5 parts of catalyst, 5 parts of hydrogenated castor oil and 1.5 parts of carbodiimide and add them to a mixer in sequence. Stir at 500 rpm / min for 10 min. Then add 100 parts of pre-mixed sodium silicate solution and stir at 800 rpm / min for 20 min. Degas under vacuum for 3 min to obtain component A. Step S3: Preparation of Component B: Take 100 parts of polymethyl polyphenyl polyisocyanate, 20 parts of diethylene glycol butyl ether acetate and 10 parts of polyether polyol and add them to a mixer in sequence. Stir at 400 rpm / min for 20 min and then degas under vacuum for 3 min to obtain Component B.

[0057] Comparative Example 1 The only difference from Example 1 is that the sodium silicate solution used in this comparative example is a first sodium silicate solution with a modulus of 2.1 to 2.8 and a Baume degree of 45 to 51°Bé. Everything else is the same as in Example 1.

[0058] Comparative Example 2 The only difference from Example 1 is that no thixotropic agent is added to component A in this comparative example; otherwise, it is the same as Example 1.

[0059] Comparative Example 3 The only difference from Example 1 is that no polyether polyol is added to component B of this comparative example; otherwise, it is the same as Example 1.

[0060] Comparative Example 4 The only difference from Example 1 is that no reinforcing agent is added to component A of this comparative example; otherwise, it is the same as Example 1.

[0061] Comparative Example 5 The only difference from Example 1 is that the catalyst used in component A of this comparative example is N,N-dimethylcyclohexylamine, while the rest is the same as in Example 1.

[0062] Comparative Example 6 Commercially available polyurethane anchoring agents.

[0063] Application Example 1 In Example 1, components A and B were thoroughly mixed at a volume ratio of 1:1 and then solidified underwater.

[0064] Application Example 2 In Example 1, components A and B were thoroughly mixed at a volume ratio of 1:1 and then solidified at 10°C.

[0065] Anchoring tests were conducted on the anchoring agents prepared in Examples 1 to 3 and Comparative Examples 1 to 6, respectively. The test methods and standards were in accordance with the "Polymer Materials for Reinforcing Coal and Rock Masses in Coal Mines".

[0066] The performance data of Examples 1 to 3, Comparative Examples 1 to 6, and Application Examples 1 to 2 at room temperature are shown in Table 1.

[0067] Table 1 Test Results

[0068] As shown in Table 1, the anchoring agent provided by the present invention is significantly superior to the comparative example and commercially available products in terms of curing speed, early strength and final strength, and has a suitable viscosity, which is convenient for pumping.

[0069] The anchoring agents prepared in Examples 1 to 3 were subjected to compressive strength tests, and the test results are as follows: Figure 2 As shown. Figure 2 The anchoring agent prepared by this invention not only has high compressive strength, but also has a strain greater than 35%, breaking through the problem of traditional anchoring materials being "strong but brittle". It plays a more effective supporting role in fractured rock mass, soft rock and high-stress surrounding rock affected by mining.

[0070] Comparative analysis of the performance test data from Examples 1-3 and Comparative Examples 1-5 shows that the anchoring agent prepared by this invention achieves functional optimization and synergistic effect through the synergistic compounding of specific components. Specifically, Examples 1-3 are significantly superior to the comparative examples in terms of curing time, 1-hour compressive strength, and 24-hour compressive strength, indicating that its formulation design has significant advantages in terms of reactivity, early strength development, and final mechanical properties.

[0071] Specifically, comparing Example 1 with Comparative Example 4 reveals that the 1-hour compressive strength and 24-hour compressive strength of Example 1, at 43.8 MPa and 65.8 MPa respectively, are significantly higher than those of Comparative Example 4 (32.5 MPa and 45.5 MPa). This result fully demonstrates that the addition of the reinforcing agent plays a crucial role in improving the strength of the anchoring material. The mechanism of action is as follows: the selected reinforcing agent is a bifunctional silane coupling agent. One functional group at one end of its molecule can form a strong chemical bond with the surface of inorganic materials, while the other functional group forms a chemical bond with organic resins. This greatly improves the interfacial interaction of the organic-inorganic hybrid structure within the anchoring agent, enhances the interfacial bonding strength, and ultimately significantly improves the overall mechanical properties of the material.

[0072] The anchoring agent prepared in Example 1 was applied to a roadway support site at a depth of 700 meters in a mine. The roof lithology in this area is sandy mudstone with a high level of in-situ stress. High-strength hollow grouting anchor cables with diameters of 21.8×4000mm were used. Components A and B of the anchoring agent were separately connected to a two-component pumping system and mixed and pumped at a volume ratio of 1:1. The pumping pressure was stabilized at 5~10MPa.

[0073] The construction process showed that the entire pumping and grouting process was continuous and stable, without any blockages or leakage. The grouting time for a single hole was approximately 2 minutes, demonstrating the material's excellent adaptability to construction. The anchoring agent reached the required early strength for support one hour after grouting. After 24 hours, three anchor cables were randomly selected for destructive tension tests. The results showed that the loads on all three cables exceeded 295 kN, proving that their final anchoring strength met the requirements for high-standard support.

[0074] In summary, the present invention is reasonably designed and has the following advantages: (1) The anchoring agent prepared by the present invention is formed by compounding two sodium silicate solutions with different moduli and reacting synergistically with component B. The resulting solid structure is dense and has significantly better curing speed, early strength and final strength than the comparative example and commercial products, and has a suitable viscosity. (2) The preparation method provided by the present invention adopts a one-step mechanical blending process, which eliminates the complex prepolymerization steps of traditional polyurethane anchoring agents. The process is simple and stable, easy to industrialize, and reduces costs and energy consumption. (3) Polymethyl polyphenyl polyisocyanate is selected to avoid the risk of high vapor pressure of small molecule isocyanate; the system does not contain toxic catalysts such as organotin, and has low VOC content, which meets the requirements of green environmental protection.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength pumpable anchoring agent, characterized in that: It consists of component A and component B, which should be mixed in a 1:1 volume ratio before use. The A component, by mass, comprises: 60-80 parts of a first sodium silicate solution, 20-40 parts of a second sodium silicate solution, 2-8 parts of a catalyst, 5-20 parts of a chain extender, 1-5 parts of a thixotropic agent, and 0.5-2 parts of a reinforcing agent. Component B, by mass, comprises: 90-110 parts isocyanate, 10-30 parts plasticizer, and 2-6 parts polyether polyol.

2. The high-strength pumpable anchoring agent according to claim 1, characterized in that: The first sodium silicate solution is a sodium silicate solution with a modulus of 2.1 to 2.8 and a Baume degree of 45 to 51°Bé. The second sodium silicate solution is a sodium silicate solution with a modulus of 2.8 to 3.5 and a Baume degree of 40 to 45°Bé.

3. A high-strength pumpable anchoring agent according to claim 1 or 2, characterized in that: The mass ratio of the first sodium silicate solution to the second sodium silicate solution is 7:

3.

4. The high-strength pumpable anchoring agent according to claim 1, characterized in that: In component A, the catalyst is selected from a complex system of tertiary amine catalysts and carboxylates, wherein the tertiary amine catalyst is selected from one or more of N,N-dimethylbenzylamine, N,N-dimethylcyclohexylamine, tetramethyl-1,6-hexanediamine, triethylenediamine, dimethylaminoethoxyethanol, and tetramethyldisyltriamine; and the carboxylate is selected from one or more of potassium acetate, potassium oleate, and potassium octanoate. The chain extender is selected from one or more of glycerol, isophorone diamine, and allyl propylene diamine; The reinforcing agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, carbodiimide, and 1,10-diaminodecane; The thixotropic agent is selected from one or more of fumed silica, precipitated silica, silane-modified silica, organobentonite, and hydrogenated castor oil.

5. The high-strength pumpable anchoring agent according to claim 1, characterized in that: In component B, the isocyanate is selected from one or more of diphenylmethane diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, trimer isocyanate, and polymethyl polyphenyl polyisocyanate; The plasticizer is selected from one or more of diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, dioctyl phthalate, and tributyl citrate.

6. A method for preparing a high-strength pumpable anchoring agent as described in any one of claims 1 to 5, characterized in that: Specifically, the steps include the following: Step S1: Prepare sodium silicate solution: Weigh the first sodium silicate solution and the second sodium silicate solution according to the ratio, and mix them evenly to obtain a sodium silicate solution; Step S2: Preparation of component A: Weigh out the chain extender, catalyst, reinforcing agent and thixotropic agent according to the ratio, mix them evenly to obtain a mixture, add the sodium silicate solution prepared in step S1 to the mixture, stir evenly and then degas to obtain component A. Step S3: Preparation of Component B: Weigh the isocyanate, plasticizer and polyether polyol according to the ratio, stir evenly and then degas to obtain Component B.

7. The method for preparing a high-strength pumpable anchoring agent according to claim 6, characterized in that: In step S2, the mixing conditions for the chain extender, catalyst, reinforcing agent and thixotropic agent are: stirring speed of 300 rpm / min and stirring time of 20 min. The mixing conditions for the mixture and the sodium silicate solution are: a stirring speed of 600 rpm / min and a stirring time of 30 min.

8. The method for preparing a high-strength pumpable anchoring agent according to claim 6, characterized in that: In step S3, the mixing conditions for isocyanate, plasticizer and polyether polyol are: stirring speed of 300 rpm / min and stirring time of 30 min.

9. The method for preparing a high-strength pumpable anchoring agent according to claim 6, characterized in that: In steps S2 and S3, the degassing process is one of vacuum centrifugal degassing, ultrasonic degassing, and static degassing. The specific operation of vacuum centrifugation degassing is as follows: the vacuum centrifugation degassing time is 1 to 5 minutes, and the vacuum degree is -0.1 MPa; The ultrasonic degassing time is 30–60 min; the static degassing time is 12–24 h.

10. An application of the high-strength pumpable anchoring agent as described in any one of claims 1 to 5, characterized in that: The anchoring agent is used in coal mine shaft support, tunnel surrounding rock reinforcement, or rock and soil anchoring in water conservancy and hydropower projects.

Images