Preparation method of green high-performance industrial solid waste-based grouting material

Abstract

The application discloses a kind of preparation methods of green high-performance industrial solid waste based grouting material, belong to industrial solid waste treatment and grouting reinforcement field, comprising: the red mud, slag, fly ash and cement are dry mixed according to predetermined proportion after being dried and ground to specified fineness, to obtain uniform dry material;Water glass and sodium hydroxide are made into composite alkali activator according to molar ratio 3:1, then pre-mixed with water and added into dry material in batches, to form wet slurry;After high-speed shearing stirring is implemented to wet slurry, it is placed and cured to obtain solid waste based slurry that can be directly used for grouting.The application significantly improves the utilization rate of solid waste, reduces environmental pressure, and is suitable for tunnel and subway engineering control stratum settlement, plugging water gushing, mine roadway support broken rock mass and underground cavern repair concrete lining crack and other related engineering.

Description

Technical Field

[0001] This invention belongs to the field of industrial solid waste treatment and grouting reinforcement, and particularly relates to a method for preparing a green, high-performance industrial solid waste-based grouting material. Background Technology

[0002] Grouting reinforcement technology plays a crucial role in engineering practices such as settlement control and water inrush sealing in tunnel and subway projects, support of fractured rock masses in mine roadways, and repair of cracks in concrete linings in underground caverns. Currently, the grouting materials widely used in these projects are still primarily traditional cement-based grouts and chemical grouts. However, the production process of traditional cement-based grouting materials has significant drawbacks. Its preparation consumes large amounts of non-renewable natural resources such as limestone and clay, and is accompanied by high energy consumption and high carbon dioxide emissions, which runs counter to the current advocacy of green mine construction and sustainable development concepts.

[0003] Furthermore, existing grouting materials also have performance limitations: their diffusion radius is often small, making it difficult to effectively penetrate and reinforce dense fine sand layers, thus limiting their reinforcement effect under complex geological conditions. Meanwhile, with the continuous development of industrial production, industries such as metallurgy, chemicals, and energy generate large amounts of industrial solid waste, such as red mud, slag, and fly ash. The long-term accumulation of these industrial solid wastes not only occupies valuable land resources, but their alkali metals and heavy metal ions can also migrate with rainwater, causing pollution and damage to surrounding soil, water bodies, and the ecological environment, becoming a major obstacle to sustainable urban development and green economic transformation. Therefore, how to efficiently and on a large scale utilize these industrial solid wastes and turn them into valuable resources is a significant challenge we currently face. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose a green, high-performance industrial solid waste-based grouting material and method, which can effectively reduce the problems of large industrial solid waste accumulation and difficult disposal, and also effectively reduce cement usage, thereby achieving the goal of cost reduction.

[0005] To achieve the above objectives, the present invention provides a method for preparing a green, high-performance industrial solid waste-based grouting material, comprising:

[0006] Red mud, slag, and fly ash that have been dried and ground to a specified fineness are dry-mixed with cement in a predetermined ratio to obtain a uniform dry material.

[0007] Water glass and sodium hydroxide are mixed in a molar ratio of 3:1 to form a composite alkali activator. After being premixed with water, the mixture is added to the dry material in batches to form a wetting slurry.

[0008] After subjecting the wetted slurry to high-speed shearing and stirring, it is allowed to stand and mature to obtain a solid waste-based slurry that can be directly used for grouting.

[0009] Preferably, the process of obtaining red mud that has been dried and ground to a specified fineness includes:

[0010] The red mud was dried at 105±5℃ to a moisture content of <1%, and then ground to an average particle size of 4–10μm.

[0011] The chemical composition of the red mud includes Fe2O3, Al2O3, SiO2 and Na2O.

[0012] Preferably, the predetermined proportions are 20-30% red mud, 30-40% slag, 20-30% fly ash, and 10-20% cement;

[0013] The slag has a particle size distribution of 7-14 μm and its chemical composition includes CaO, Al2O3 and SiO2.

[0014] The fly ash has a particle size distribution of 1.4-7.2 μm and its chemical composition includes CaO, Al2O3 and CaCl2;

[0015] The cement is silicate cement with a particle size distribution of 3.1~14.7μm;

[0016] The silicate cement is used to fill pores and accelerate hydration.

[0017] Preferably, the water glass has a modulus of 1.0–1.2 to provide [SiO4]. 4- skeleton;

[0018] The sodium hydroxide concentration is 6–8 mol / L, which is used to depolymerize the silica-alumina phase in red mud and activate the activity of slag and fly ash.

[0019] The composite alkali activator accounts for 4–6% of the total amount of cementitious materials.

[0020] Preferably, the batch addition includes first adding 60% of the total amount of the compound alkali activator and stirring for 1 minute, and then adding the remaining 40% after a 30-second interval.

[0021] Preferably, the water-to-solid ratio of the premixed water is 0.4–0.6, and the water temperature is controlled at 20±2℃.

[0022] Preferably, the high-speed shear mixing includes mixing at 1200 rpm for 4 minutes, then reducing to a low speed and mixing for another 2 minutes.

[0023] Preferably, the static curing process includes standing in a sealed environment at 20±2℃ for 10–15 minutes.

[0024] Preferably, the method further includes evaluating the grouting reinforcement effect;

[0025] The evaluation process includes:

[0026] The solid waste-based slurry was injected into the target formation using a pneumatic grouting machine, and the grouting volume, solidified volume, porosity, and loss rate were recorded.

[0027] The grouting filling rate is obtained based on the grouting volume, solidification volume, porosity, and loss rate.

[0028] The compressive strength and permeability coefficient were measured before and after grouting. The compressive strength increase rate and permeability coefficient decrease rate were calculated based on the grouting filling rate, compressive strength and permeability coefficient. A comprehensive quality index was constructed in a weighted manner. The grouting reinforcement effect was evaluated based on the comprehensive quality index, and the evaluation results were obtained.

[0029] Compared with the prior art, the present invention has the following advantages and technical effects:

[0030] (1) This invention develops a green and high-performance industrial solid waste-based grouting material, which transforms difficult-to-dispose-of industrial solid wastes such as red mud, slag, and fly ash into the core components of the grouting material, improves the utilization rate of solid waste, effectively improves the environmental pollution caused by excessive accumulation of industrial solid waste, and partially replaces traditional cement with industrial solid waste cementing material, effectively reducing the use of cement and reducing carbon emissions.

[0031] (2) The green high-performance industrial solid waste-based grouting reinforcement material developed in this invention has both excellent fluidity and strength, and can deeply fill the micro-cracks that traditional materials cannot reach, significantly improving the uniformity and integrity of reinforcement.

[0032] (3) The present invention prepares a novel alkaline activator composed of water glass and sodium hydroxide, which significantly improves the reaction efficiency and structural density of the material through a dual mechanism: on the one hand, it dissociates the active components in solid waste, and on the other hand, it constructs a stable silicon-aluminum skeleton.

[0033] (4) This invention scientifically adjusts solid waste raw materials of different particle sizes, giving full play to the morphological effect of fly ash and the filling characteristics of red mud, so that the slurry has excellent fluidity and micro-permeability, effectively overcoming the technical bottleneck of traditional materials in microcrack reinforcement.

[0034] (5) The present invention achieves precise control of the solid-liquid interface and reaction uniformity through a four-stage process of dry mixing, step-by-step wetting, high-speed activation and static curing, thus avoiding the risk of slurry stratification and agglomeration.

[0035] (6) The novel solid waste-based grouting material studied in this invention significantly reduces the amount of cement used, reduces material costs by utilizing industrial solid waste, reduces solid waste disposal costs, and reduces energy consumption of grouting equipment through high fluidity grout. Attached Figure Description

[0036] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention;

[0038] Figure 2 This is a flowchart of the grouting reinforcement effect evaluation method according to an embodiment of the present invention. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0041] like Figure 1 As shown, this embodiment provides a method for preparing a green, high-performance industrial solid waste-based grouting material, comprising:

[0042] Red mud, slag, and fly ash that have been dried and ground to a specified fineness are dry-mixed with cement in a predetermined ratio to obtain a uniform dry material.

[0043] Water glass and sodium hydroxide are mixed in a molar ratio of 3:1 to form a composite alkali activator. After being premixed with water, the mixture is added to the dry material in batches to form a wetted slurry.

[0044] After high-speed shearing and mixing of the wetted slurry, it is allowed to stand and mature to obtain a solid waste-based slurry that can be directly used for grouting.

[0045] Specifically, the green high-performance industrial solid waste-based grouting material in this embodiment is composed of 20%-30% red mud, 30%-40% slag, 20%-30% fly ash, 10%-20% cement, and a composite alkali activator. Its preparation process mainly includes the following four steps:

[0046] Step 1: Add the pretreated red mud, slag, fly ash and cement into the mixer in proportion. First, dry mix at low speed for 5 minutes to ensure that the components are fully mixed and in contact. Then mix at medium speed for 3 minutes to break up the agglomeration caused by van der Waals forces between particles and enhance the fluidity between slag and fly ash.

[0047] Step 2: Premix the composite alkali activator solution with water (water-to-solid ratio of 0.4-0.6). Pour the premixed composite alkali activator into the dry material in batches and mix at low speed for 2 minutes in a mixer to ensure that the liquid phase uniformly coats the solid particles and forms a stable solid-liquid interface, which can effectively ensure particle wetting.

[0048] Step 3: Stir the slurry at 1200 rpm for about 4 minutes to ensure that the components are fully dispersed and to activate the gelation reaction. Then, reduce the stirring speed to low for about 2 minutes to release air bubbles and increase the density of the slurry.

[0049] Step 4: Transfer the slurry into a sealed container and let it stand for 10-15 minutes at 20±2℃ to allow unreacted particles to be fully impregnated, thus obtaining a green, high-performance industrial solid waste-based grouting material.

[0050] Furthermore, the process of obtaining red mud that has been dried and ground to a specified fineness includes:

[0051] The red mud was dried at 105±5℃ to a moisture content of <1%, and then ground to an average particle size of 4–10μm.

[0052] The chemical composition of red mud includes Fe2O3, Al2O3, SiO2 and Na2O.

[0053] Furthermore, the red mud described in this embodiment is dried in an oven at 105±5℃ for 24 hours until the moisture content is less than 1%. The dried red mud is then ground by a pulverizer to an average particle size of 4-10μm. Its main chemical components are Fe2O3, Al2O3, SiO2 and Na2O. Its main function is to promote better reaction of each component, enhance density and improve fluidity.

[0054] Furthermore, in this embodiment, the red mud is dried to a moisture content of <1% to eliminate the interference of free water on accurate metering and mixing uniformity. Through extensive experimentation, this embodiment demonstrates that grinding the red mud to the micron level (4-10 μm) significantly increases its specific surface area and reactivity, transforming it from a simple filler into a reactive component. Simultaneously, it optimizes particle size distribution and enhances the system's density.

[0055] Furthermore, the predetermined proportions are: 20–30% red mud, 30–40% slag, 20–30% fly ash, and 10–20% cement;

[0056] The slag has a particle size distribution of 7-14 μm and its chemical composition includes CaO, Al2O3 and SiO2.

[0057] Specifically, the slag is selected from S95 grade mineral powder with a particle size distribution of 7-14μm. Its main chemical components are CaO, Al2O3 and SiO2, and its main function is to improve the early strength of the grouting material.

[0058] The particle size distribution of fly ash is 1.4-7.2 μm, and its chemical composition includes CaO, Al2O3 and CaCl2.

[0059] Specifically, the fly ash has a particle size distribution of 1.4-7.2μm and its main chemical components are CaO, Al2O3 and CaCl2. Its main function is to improve fluidity by exerting the "microbead effect".

[0060] This embodiment uses S95 grade mineral powder, which has a high activity index (7d≥75%, 28d≥95%), effectively ensuring the early and later strength of the material. For fly ash, this embodiment also incorporates fine spherical particles (microspheres) to effectively improve the rheological properties of the slurry.

[0061] The cement is silicate cement with a particle size distribution of 3.1~14.7μm;

[0062] Silicate cement is used to fill pores and accelerate hydration.

[0063] Specifically, the cement used is silicate cement with a particle size distribution of 3.1~14.7μm. Its main function is to fill pores and accelerate hydration, thus compensating for the insufficient early strength of solid waste.

[0064] Furthermore, the material proportioning parameters in this embodiment are selected based on the optimal synergistic effect of the active components verified through extensive experiments. The experimental principles include: red mud is rich in alkali metals, providing an alkaline environment and participating in the reaction, but its activity is low, so its proportion should not be too high. Slag and fly ash are the main sources of activity, and their proportions must ensure that the system can generate a sufficient amount of gel products such as hydrated calcium silicate (CSH) to meet strength requirements. Cement, as the "crystal nucleus" and early strength source, is added to compensate for the slow early strength development of a pure solid waste system. This proportion range maximizes the utilization of solid waste (total solid waste exceeding 80%) while ensuring performance, conforming to the principle of encouraging large-scale utilization of industrial waste such as fly ash in GB / T 50146-2014 "Technical Specification for Application of Fly Ash Concrete".

[0065] Furthermore, the modulus of water glass is 1.0–1.2, and its main function is to provide [SiO4]. 4- skeleton;

[0066] The modulus of water glass is a core parameter. If the modulus is too low (<1.0), there will be too few silicate ions, making it difficult to form a stable three-dimensional network [SiO4]4- framework; if the modulus is too high (>1.2), the solution is prone to gelation, resulting in poor stability and reduced excitation efficiency. In this embodiment, a modulus range of 1.0-1.2 is set to provide the optimal range for suitable silicate concentration and solubility.

[0067] The concentration of sodium hydroxide is 6–8 mol / L, and its main function is to depolymerize the silica-alumina phase in red mud and activate the activity of slag and fly ash.

[0068] The NaOH concentration is chosen to be 6-8 mol / L to provide sufficient OH- concentration to quickly break the Si-O and Al-O bonds in the glassy structure of slag and fly ash, releasing active monomers. Too low a concentration will result in a weak activation effect, while too high a concentration will easily lead to an overly violent reaction and the phenomenon of "alkali blooming".

[0069] The composite alkali activator accounts for 4–6% of the total amount of cementitious materials and is composed of water glass and sodium hydroxide in a ratio of 3:1.

[0070] Furthermore, in this embodiment, the composite alkali activator is set at a proportion of 4%-6%. This is because too low a dosage (<4%) would fail to fully depolymerize the glassy structure of the slag and fly ash, leading to incomplete reaction and insufficient strength development; while too high a dosage (>6%) would result in an excessively rapid reaction, making it difficult to control the slurry setting time and increasing the risk of alkali-aggregate reaction, thus deteriorating long-term volume stability. Therefore, a dosage of 4%-6% is the optimal range, verified through experiments, that balances workability, strength, and durability in this embodiment.

[0071] Furthermore, adding the compound alkali activator in batches, including first adding 60% of the total amount of the compound alkali activator and stirring for 1 minute, followed by adding the remaining 40% after a 30-second interval, can effectively prevent moisture concentration from causing local agglomeration.

[0072] Furthermore, the water-to-solid ratio of the premixed product is 0.4–0.6, and the water temperature is controlled at 20±2℃ to avoid temperature fluctuations causing the alkaline activator to crystallize.

[0073] Furthermore, this embodiment ensures that the grout has good fluidity and pumpability by setting a water-to-solid ratio of 0.4-0.6, thus meeting the requirements of grouting construction. An excessively high water-to-solid ratio will reduce the final strength and increase the risk of bleeding, while an excessively low ratio will result in poor fluidity and inability to penetrate into fine cracks.

[0074] Furthermore, the high-speed shear mixing includes mixing at 1200 rpm for 4 minutes, then reducing to a low speed and mixing for another 2 minutes.

[0075] Furthermore, the standing curing process includes standing in a closed environment at 20±2℃ for 10–15 minutes.

[0076] Furthermore, the mixing process in this embodiment includes dry mixing, low speed, medium speed, high speed 1200 rpm, and standing maturation.

[0077] This embodiment optimizes the solid waste raw material characteristics by first dry mixing to ensure uniformity, then adding liquid in batches to avoid clumping, and using high-speed stirring (1200 rpm) to provide high shear force, which fully disperses the particles and promotes the initiation of the reaction. The static curing (10-15 min) is similar to the "dormant" period of concrete, allowing preliminary hydration reactions and ion migration within the grout, releasing some air bubbles, and improving grout stability, which is crucial for ensuring the density of the grout.

[0078] As an additional implementation method, the preparation method includes the following steps:

[0079] Step 1: Dry the red mud in an oven at 105℃ for 24 hours until the moisture content is less than 1%. After drying, grind the red mud with a maximum particle size of 50μm and a median particle size of 20μm. Use S95 grade mineral powder for slag, with a particle size distribution controlled at 7-14μm. Control the particle size distribution of fly ash at 10-30μm. Use silicate cement, with a particle size distribution controlled at 15-25μm.

[0080] Step 2: Add the pretreated red mud, slag, fly ash and cement to the mixer at a ratio of 25% red mud, 30% slag, 30% fly ash and 15% cement. First, dry mix at low speed for 5 minutes to ensure that the components are fully mixed and in contact, and then mix at medium speed for 3 minutes.

[0081] Step 3: Mix water glass with a modulus of 1.0-1.2 and sodium hydroxide with a concentration of 6-8 mol / L in a 3:1 ratio to prepare a composite alkali activator. Then, premix it with water at a water-to-solid ratio of 0.6. The premixed composite alkali activator is added in two parts: first, add 60% of the total amount and stir for 1 minute; then, add the remaining 40% after a 30-second interval, while controlling the water temperature at 20°C and mixing at low speed in a mixer for 2 minutes to ensure that the liquid phase uniformly coats the solid particles and forms a stable solid-liquid interface, which can effectively ensure particle wetting. The composite alkali activator accounts for 6% of the cementitious material.

[0082] Step 4: Place the slurry in a high-speed mixer and stir at 1200 rpm for about 4 minutes to activate the gelation reaction, then reduce the speed to low and stir for about 2 minutes to release the air bubbles.

[0083] Step 5: Transfer the slurry into a sealed container and let it stand for 15 minutes at 20°C.

[0084] Step Six: Based on the on-site tunnel water-blocking project, use matching grouting equipment to perform grouting reinforcement with green high-performance industrial solid waste-based grouting materials:

[0085] Test parameters: Grouting was performed on the leaking area using a pneumatic grouting machine, with the pressure controlled between 0-5 MPa, and the data from the pneumatic grouting machine was recorded. Q =15m3 Obtained through drilling measurements V =50m 3 , n =18%, β =5%;

[0086] Core samples with a diameter ≥50mm were drilled from adjacent locations before and after grouting, and uniaxial compressive strength tests were conducted to obtain the core strength: s c-pre =9MPa, s c-post =16MPa;

[0087] Permeability coefficient: k pre =5×10 -4 cm / s, k post =2×10 -6 cm / s;

[0088] oh 1 = 0.3 oh 2 = 0.2, oh 3 = 0.5;

[0089] Comprehensive quality indicators of grouting reinforcement effect:

[0090] ;

[0091] ;

[0092] ;

[0093] ;

[0094] The basic properties of the green high-performance industrial solid waste-based grouting material obtained in this embodiment are shown in Table 1.

[0095] Table 1

[0096]

[0097] Because MDRI≥85%, the grouting reinforcement effect of this tunnel water-blocking project is rated as excellent.

[0098] Furthermore, such as Figure 2 As shown, the method described in this embodiment also includes evaluating the grouting reinforcement effect;

[0099] The evaluation process includes:

[0100] The solid waste-based slurry was injected into the target formation using a pneumatic grouting machine, and the grouting volume, solidified volume, porosity, and loss rate were recorded.

[0101] The grouting filling rate is obtained based on the grouting volume, solidification volume, porosity, and loss rate.

[0102] The compressive strength and permeability coefficient were measured before and after grouting. The compressive strength increase rate and permeability coefficient decrease rate were calculated based on the grouting filling rate, compressive strength and permeability coefficient. A comprehensive quality index was constructed in a weighted manner. The grouting reinforcement effect was evaluated based on the comprehensive quality index, and the evaluation results were obtained.

[0103] Furthermore, this embodiment quantifies the degree to which the grout fills the voids by measuring the grouting volume, solidification volume, and porosity, thereby evaluating the effectiveness of the grouting.

[0104] This embodiment evaluates the improvement in the mechanical properties of soil and rock mass through uniaxial compressive strength testing of rock cores. Specifically, by comparing the strength values ​​of rock cores before and after grouting, the enhancement effect of the grout consolidation on the formation strength is directly reflected.

[0105] One of the core purposes of grouting is to reduce the permeability of the formation and block water flow channels. Therefore, this embodiment evaluates the water-stopping effect by measuring the change in permeability coefficient before and after grouting.

[0106] This embodiment uses a multi-index weighted comprehensive evaluation method to evaluate the grouting reinforcement effect. The weights are not arbitrarily set, but must be based on specific project requirements and industry standards. For example:

[0107] In engineering projects primarily focused on water plugging and seepage prevention (such as mine leak sealing), the weight of the permeability reduction rate (PCR) is ( oh 3) Should be maximum (e.g., 0.5), fill rate ( oh 1) and strength improvement rate ( oh 2) Second best (e.g., 0.3 and 0.2).

[0108] In projects primarily involving reinforcement and strengthening (such as foundation underpinning), the weight of the compressive strength enhancement rate (EMR) is ( oh 2) Should be maximum (e.g., 0.5), fill rate ( oh 1) and the rate of decrease in permeability coefficient ( oh 3) Second (e.g., 0.3 and 0.2).

[0109] The thresholds for evaluation levels, such as the score ranges for excellent, good, and poor, are determined through regression analysis of a large amount of engineering practice data or based on industry-recognized acceptance standards (such as the requirements for the strength and impermeability of the stratum after grouting reinforcement in JTG F60-2009 "Technical Specification for Highway Tunnel Construction"), thereby ensuring the accuracy and universality of the evaluation model.

[0110] In this step, as an optional implementation, the evaluation process includes the following steps:

[0111] Step A: Use matching grouting equipment to perform grouting reinforcement with green high-performance industrial solid waste-based grouting materials, and record the total grouting volume during the grouting process. Q Then, based on the volume of the solidified body V Porosity n and grouting loss rate β The grouting filling rate was calculated. GCR : ;

[0112] Step B: Obtain rock cores from adjacent locations before and after grouting, and conduct uniaxial compressive strength tests on the rock cores to determine the compressive strength of the soil and rock mass before grouting. and the compressive strength of the soil and rock mass after grouting The compressive strength improvement rate was calculated. EMR : ;

[0113] Step C: Before and after grouting, drill a sample with a diameter of [missing information] at the grouting location. r Depth is l The leakage rate after water injection stabilized was measured by injecting water into the borehole in sections. A Combined with the height of the water head in the borehole s This allows for the calculation of the permeability coefficient of the formation before grouting. and the permeability coefficient of the borehole formation after grouting The specific calculation formula is as follows: The rate of decrease in permeability coefficient was calculated based on the change in permeability coefficient before and after grouting. PCR : ;

[0114] Step D: Based on the grouting filling rate, compressive strength improvement rate, and permeability coefficient reduction rate, a comprehensive quality index for grouting reinforcement effect is established using a weighted analysis method. .

[0115] Furthermore, the grouting equipment in step A consists of a pneumatic grouting machine, a grout storage tank, a high-speed mixer, grouting pipes, and advanced small guide pipes. The pneumatic grouting machine operates at a pressure of 0–5 MPa and a grouting rate of 0–30 L / min, meeting the requirements for on-site grouting reinforcement. The high-speed mixer rotates at 2800 r / min, enabling high-speed and uniform mixing of the grout.

[0116] Furthermore, in step D... These are the influencing factors of the grouting filling rate, compressive strength improvement rate, and permeability coefficient reduction rate on the grouting reinforcement effect, respectively, and the three satisfy the following conditions. .

[0117] Furthermore, based on the construction in step D... MDRIThe grouting reinforcement effect is divided into three levels: excellent, good, and poor, and corresponding comprehensive evaluation index thresholds are set. The classification of the comprehensive quality index level of grouting reinforcement effect is shown in Table 2.

[0118] Table 2

[0119]

[0120] This embodiment comprehensively considers multiple factors such as grouting filling rate, compressive strength improvement rate before and after grouting, and permeability coefficient of the borehole formation before and after grouting, to construct a universal, multi-parameter, and highly accurate evaluation model, thereby completing an accurate evaluation of the grouting reinforcement effect.

[0121] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a green, high-performance industrial solid waste-based grouting material, characterized in that, include: Red mud, slag, and fly ash that have been dried and ground to a specified fineness are dry-mixed with cement in a predetermined ratio to obtain a uniform dry material. Water glass and sodium hydroxide are mixed in a molar ratio of 3:1 to form a composite alkali activator. After being premixed with water, the mixture is added to the dry material in batches to form a wetting slurry. After subjecting the wetted slurry to high-speed shearing and stirring, it is allowed to stand and mature to obtain a solid waste-based slurry that can be directly used for grouting. The predetermined proportions are: 20-30% red mud, 30-40% slag, 20-30% fly ash, and 10-20% cement. The water glass has a modulus of 1.0–1.2 and is used to provide [SiO4]. 4 ⁻Skeleton; The composite alkali activator accounts for 4–6% of the total amount of cementitious materials; The process of obtaining red mud that has been dried and ground to a specified fineness includes: The red mud was dried at 105±5℃ to a moisture content of <1%, and then ground to an average particle size of 4–10μm. The chemical composition of the red mud includes Fe2O3, Al2O3, SiO2 and Na2O; The slag has a particle size distribution of 7-14 μm and its chemical composition includes CaO, Al2O3 and SiO2. The fly ash has a particle size distribution of 1.4-7.2 μm and its chemical composition includes CaO, Al2O3 and CaCl2. The cement is silicate cement with a particle size distribution of 3.1~14.7μm; The silicate cement is used to fill pores and accelerate hydration; The batch addition includes first adding 60% of the total amount of the compound alkali activator and stirring for 1 minute, then adding the remaining 40% after a 30-second interval. The method also includes evaluating the grouting reinforcement effect; The evaluation process includes: The solid waste-based slurry was injected into the target formation using a pneumatic grouting machine, and the grouting volume, solidified volume, porosity, and loss rate were recorded. The grouting filling rate is obtained based on the grouting volume, solidification volume, porosity, and loss rate. The compressive strength and permeability coefficient were measured before and after grouting. The compressive strength increase rate and permeability coefficient decrease rate were calculated based on the grouting filling rate, compressive strength and permeability coefficient. A comprehensive quality index was constructed in a weighted manner. The grouting reinforcement effect was evaluated based on the comprehensive quality index, and the evaluation results were obtained.

2. The method according to claim 1, characterized in that, The sodium hydroxide concentration is 6–8 mol / L, used to depolymerize the silica-alumina phase in red mud and activate the activity of slag and fly ash.

3. The method according to claim 1, characterized in that, The water-to-solid ratio of the premixed water is 0.4–0.6, and the water temperature is controlled at 20±2℃.

4. The method according to claim 1, characterized in that, The high-speed shear mixing includes mixing at 1200 rpm for 4 minutes, then reducing to a low speed and mixing for another 2 minutes.

5. The method according to claim 1, characterized in that, The static curing process includes standing in a closed environment at 20±2℃ for 10–15 minutes.

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