Lightweight soil stabilizer as well as preparation method and application thereof

Abstract

The invention provides a lightweight soil stabilizer as well as a preparation method and application thereof, and belongs to the technical field of soil engineering materials. The light soil stabilizer comprises the following components in parts by weight: 0-10 parts of red mud, 0-10 parts of steel slag, 40-60 parts of mineral powder, 20-30 parts of gypsum, 10-20 parts of carbide slag, 5-10 parts of a foaming agent, 0.5-2 parts of a foam stabilizer and 70-100 parts of water. Wherein the foaming agent is a mixture of sodium bicarbonate and aluminum potassium sulfate. The light soil stabilizer is prepared from the red mud, the steel slag, the mineral powder, the gypsum, the carbide slag, the foaming agent and the foam stabilizer, and CO2 is used as foaming gas, so that the obtained soil stabilizer not only has good mechanical properties and construction properties, but also can absorb a large amount of solid wastes, and is environment-friendly. The method can be applied to slope repair, closed or underground construction projects such as tunnels and goaf on a large scale.

Description

Technical Field

[0001] This invention belongs to the field of soil engineering materials technology, and particularly relates to a lightweight soil stabilizer, its preparation method and application. Background Technology

[0002] With the high-quality development of the social economy, the scale of infrastructure construction continues to expand, and engineering projects, such as road and bridge engineering, face many challenges. In particular, under narrow working spaces or complex geological conditions, traditional backfill materials can no longer meet the quality and schedule requirements of modern engineering construction due to technical bottlenecks such as difficulty in achieving the required compaction degree, significant post-construction settlement, and low construction efficiency.

[0003] Fluidized solidified soil, a novel geotechnical engineering material, is prepared from soil or industrial waste as a base material through precise proportioning of solidifying agent and water. This material offers significant engineering advantages: its high fluidity allows for self-leveling and self-compacting filling in confined and complex construction environments, effectively reducing manual intervention and improving construction efficiency; its self-compacting properties ensure the integrity and density of the filling, significantly reducing the risk of collapse caused by insufficient layered compaction in traditional backfilling. Simultaneously, fluidized solidified soil possesses stable mechanical properties, exhibiting outstanding performance in impermeability and durability, meeting the technical requirements of various engineering load-bearing conditions.

[0004] However, in some engineering scenarios, such as addressing uneven settlement of roadbeds, bridge approach slab settlement, and excessive earth pressure on retaining walls, it is necessary to reduce the load on construction sites. Based on this engineering requirement, optimizing fluidized solidified soil into lightweight fluidized solidified soil, thus transforming backfill materials from heavy-load to light-load, becomes an effective way to solve the aforementioned engineering problems. Therefore, providing a lightweight soil stabilizer that combines excellent fluidity, stability, and lightweight properties is of great significance for promoting the advancement of geotechnical engineering technology and improving the quality of engineering construction. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a lightweight soil stabilizer, its preparation method, and its application. The prepared lightweight soil stabilizer has the advantages of light weight, good fluidity, stable performance, low cost, and convenient construction. It can effectively perform the functions of load reduction, filling, and seepage prevention, thereby solving problems such as uneven settlement and bridge approach slab settlement caused by existing fluidized solidified soil in some engineering fields.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a lightweight soil stabilizer, comprising the following raw materials by weight: 0-10 parts of red mud; 0-10 parts of steel slag; 40-60 parts of mineral powder; 20-30 parts plaster; 10-20 parts of calcium carbide slag; 5-10 parts of foaming agent; Foam stabilizer 0.5-2 parts; 70-100 parts water; The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate, used to generate carbon dioxide gas for foaming after the curing agent is mixed with water.

[0007] This invention primarily utilizes industrial solid waste (red mud, steel slag, mineral powder, carbide slag, and industrial gypsum). It leverages the volcanic ash activity of materials such as mineral powder and red mud, and under alkali and sulfate activation, promotes the depolymerization of silicon-oxygen tetrahedra, releasing active ions. The addition of alkali metal cations further promotes the repolymerization of silicon-oxygen tetrahedra, forming structurally stable hydration products. The foaming agent (sodium bicarbonate and potassium aluminum sulfate) undergoes a double hydrolysis reaction when mixed with water: Al… 3+ +3HCO3 - =Al(OH)3↓+3CO2↑, CO2 gas forms uniform bubbles under the action of foam stabilizer, realizing the lightweighting of the curing agent; the ratio range of each raw material ensures the balance between bonding strength and lightweight characteristics, avoiding insufficient strength due to excessive solid waste or loose structure due to excessive foaming agent.

[0008] Furthermore, the mass ratio of sodium bicarbonate to potassium aluminum sulfate in the foaming agent is 3:1. Sodium bicarbonate (HCO3) - Donor) and potassium aluminum sulfate (Al) 3+ The ratio of donors directly affects the rate of double hydrolysis reaction, CO2 production and foam volume. Too high or too low a ratio will lead to a reaction that is too fast (bubbles are easy to escape) or too slow (insufficient foaming). A suitable ratio can control the uniformity of bubbles (fine pore structure).

[0009] Furthermore, the foam stabilizer is at least one of hydroxypropyl methylcellulose ether, dodecyl dimethyl ammonium oxide, and coconut oil diethanolamide. The amphiphilic molecular structure of the foam stabilizer can be adsorbed on the surface of CO2 bubbles to form a dense adsorption layer, reduce the free energy of the gas-liquid interface, inhibit bubble aggregation, floating, or rupture, and maintain the gas-liquid-solid three-phase equilibrium.

[0010] Furthermore, the sodium bicarbonate content is ≥90%, and the potassium aluminum sulfate is potassium aluminum sulfate dodecahydrate, with an effective component content of ≥90%.

[0011] Furthermore, the mineral powder is S95 grade mineral powder with a particle size ≤20μm. S95 mineral powder is a highly active slag powder with high SiO2 and Al2O3 content, which can fully undergo pozzolanic reaction in an alkaline environment to generate hydrated calcium silicate (CSH) gel; the particle size ≤20μm can increase the specific surface area and improve the contact area between the mineral powder and other materials, thereby further improving the pozzolanic activity of the mineral powder.

[0012] Furthermore, the gypsum is at least one of industrial desulfurization gypsum, phosphogypsum, and titanium gypsum. It provides the necessary Ca for the depolymerization and repolymerization of volcanic ash materials such as mineral powder and red mud. 2+ and SO4 2- Ions promote the reaction to form ettringite.

[0013] Furthermore, the CaO content in the carbide slag is greater than 50%.

[0014] The present invention also provides a method for preparing the above-mentioned lightweight soil stabilizer, comprising the following steps: Weigh each raw material according to the specified weight proportions, mix and stir the raw materials to obtain the lightweight soil stabilizer.

[0015] Furthermore, the stirring time shall not exceed 5 minutes.

[0016] In the preparation process of the lightweight soil stabilizer of this invention, mixing and stirring ensure that the raw materials are evenly dispersed. At this time, the foaming agent comes into full contact with water and undergoes a double hydrolysis reaction, generating a large amount of CO2, causing volume expansion. The presence of the foam stabilizer ensures the stability of the bubbles, providing reaction time for the cementitious material. Simultaneously, the solid waste raw materials undergo a "depolymerization-repolymerization" reaction in an alkaline environment to form a hardened body. The simultaneous occurrence of these two reactions gives the stabilizer excellent mechanical properties and lightweight characteristics. Specifically, the core of the foaming process in this invention is the double hydrolysis gas-generating reaction. After mixing the foaming agent with water, sodium bicarbonate and potassium aluminum sulfate rapidly dissolve and ionize, Al... 3+ (From potassium aluminum sulfate) and HCO3 - (From sodium bicarbonate) undergoes a strong double hydrolysis reaction, producing aluminum hydroxide precipitate and CO2 gas. The generated CO2 gas is rapidly encapsulated in water by a foam stabilizer, preventing gas leakage. As the CO2 gas gradually rises in water, it is again encapsulated by the foam stabilizer when it reaches the liquid surface, further enhancing the stability of the CO2 bubbles. With the occurrence of the hydrolysis reaction, the accumulation of CO2 bubbles gradually increases. During this period, the solid waste slurry gradually coagulates and hardens. When the foaming force generated by the release of CO2 gradually balances with the resistance generated by the hardening of the solid waste slurry, it tends to stabilize, eventually forming a stable foamed and hardened body.

[0017] The present invention also provides a lightweight fluidized solidified soil, comprising the above-mentioned lightweight soil stabilizer, and the preparation method includes the following steps: (1) Mix the engineering soil sample with water to obtain mud; (2) Add the above-mentioned lightweight soil stabilizer to the slurry and mix. (3) The mixed slurry is poured into a mold, foamed and cured to obtain lightweight fluid solidified soil.

[0018] The present invention also provides the application of the above-mentioned lightweight soil stabilizer and / or the above-mentioned lightweight fluidized solidified soil in soft soil foundation treatment, slope repair, roadbed load reduction filling, bridge abutment backfilling or tunnel goaf filling projects.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects: (1) The lightweight soil stabilizer prepared by the present invention is made entirely from industrial solid waste as raw material, which can make large-scale use of solid waste and realize the utilization of large-scale industrial solid waste.

[0020] (2) The lightweight soil stabilizer of the present invention is prepared by CO2 foaming process. It has the advantages of light weight, stable performance and convenient construction. It can effectively solve or alleviate the load reduction requirements of the construction site and solve problems such as uneven settlement of roadbed, bridge approach slab, and excessive soil pressure on retaining wall.

[0021] (3) In the preparation process of the lightweight soil stabilizer of the present invention, CO2 is used as the foaming gas, which does not produce combustion-supporting or flammable and explosive gases, and does not pollute the construction personnel and the surrounding environment. It can be applied to a variety of engineering fields, including tunnels, mining areas and other closed or underground construction projects. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to 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. Every smaller range between any stated value or intermediate value within a stated range, and 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] This invention provides a lightweight soil stabilizer, comprising the following raw materials by weight: 0-10 parts of red mud; 0-10 parts of steel slag; 40-60 parts of mineral powder; 20-30 parts plaster; 10-20 parts of calcium carbide slag; 5-10 parts of foaming agent; Foam stabilizer 0.5-2 parts; 70-100 parts water; The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate, which is used to generate carbon dioxide gas for foaming after the curing agent is mixed with water.

[0028] In a preferred embodiment of the present invention, the mass ratio of sodium bicarbonate to potassium aluminum sulfate in the foaming agent is 3:1.

[0029] In a preferred embodiment of the present invention, the foam stabilizer is at least one of hydroxypropyl methylcellulose ether, dodecyl dimethyl ammonium oxide, and coconut oil diethanolamide.

[0030] In a preferred embodiment of the present invention, the content of sodium bicarbonate is ≥90%, and the potassium aluminum sulfate is potassium aluminum sulfate dodecahydrate, with an effective component content of ≥90%.

[0031] In a preferred embodiment of the present invention, the mineral powder is S95 grade mineral powder with a particle size ≤20μm.

[0032] In a preferred embodiment of the present invention, the gypsum is at least one of industrial desulfurization gypsum, phosphogypsum, and titanium gypsum.

[0033] In a preferred embodiment of the present invention, the CaO content in the carbide slag is greater than 50%.

[0034] This invention also provides a method for preparing the above-mentioned lightweight soil stabilizer, comprising the following steps: Weigh each raw material according to the specified weight proportions, mix and stir the raw materials to obtain a lightweight soil stabilizer.

[0035] In a preferred embodiment of the present invention, the stirring time does not exceed 5 minutes.

[0036] This invention also provides a lightweight fluidized solidified soil, comprising the above-mentioned lightweight soil stabilizer, and the preparation method includes the following steps: (1) Mix the engineering soil sample with water to obtain mud; (2) Add the above-mentioned lightweight soil stabilizer to the mud and mix it. (3) The mixed slurry is poured into a mold, foamed and cured to obtain lightweight fluid solidified soil.

[0037] The embodiments of the present invention also provide the application of the above-mentioned lightweight soil stabilizer and / or the above-mentioned lightweight fluidized solidified soil in soft soil foundation treatment, slope repair, roadbed load reduction filling, bridge abutment backfilling or tunnel mining area filling projects.

[0038] All raw materials used in the embodiments of the present invention were commercially available. The chemical composition of each raw material used in the embodiments is shown in Table 1 below.

[0039] Table 1 Chemical composition of raw materials (wt.%) In the embodiments of this invention, unless otherwise specified, "parts" refers to "number of parts by weight".

[0040] The technical solution of the present invention will be further illustrated by the following embodiments.

[0041] Example 1 A method for preparing a lightweight soil stabilizer includes the following steps: (1) Weigh the following raw materials by weight: 10 parts steel slag, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is hydroxypropyl methylcellulose ether. (2) Mix steel slag, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 3 minutes to obtain a lightweight soil stabilizer.

[0042] Example 2 A method for preparing a lightweight soil stabilizer includes the following steps: (1) Weigh the following raw materials by weight: 10 parts red mud, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is hydroxypropyl methylcellulose ether. (2) Mix red mud, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 3 minutes to obtain a lightweight soil stabilizer.

[0043] Example 3 A method for preparing a lightweight soil stabilizer includes the following steps: (1) Weigh the following raw materials by weight: 5 parts red mud, 5 parts steel slag, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is dodecyl dimethyl ammonium oxide. (2) Mix red mud, steel slag, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 3 minutes to obtain a lightweight soil stabilizer.

[0044] Example 4 A method for preparing a lightweight soil stabilizer includes the following steps: (1) Weigh the following raw materials by weight: 5 parts steel slag, 60 parts mineral powder, 25 parts gypsum, 20 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is coconut oil diethanolamide. (2) Mix steel slag, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 3 minutes to obtain a lightweight soil stabilizer.

[0045] Example 5 A method for preparing a lightweight soil stabilizer includes the following steps: (1) Weigh the following raw materials by weight: 10 parts red mud, 10 parts steel slag, 40 parts mineral powder, 20 parts gypsum, 20 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is dodecyl dimethyl ammonium oxide. (2) Mix red mud, steel slag, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 3 minutes to obtain a lightweight soil stabilizer.

[0046] Example 6 A method for preparing a lightweight soil stabilizer includes the following steps: (1) Weigh the following raw materials by weight: 10 parts red mud, 10 parts steel slag, 40 parts mineral powder, 20 parts gypsum, 20 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 100 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is dodecyl dimethyl ammonium oxide. (2) Mix red mud, steel slag, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 3 minutes to obtain a lightweight soil stabilizer.

[0047] Example 7 A method for preparing a lightweight soil stabilizer includes the following steps: (1) Weigh the following raw materials by weight: 10 parts steel slag, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 10 parts foaming agent, 2 parts foam stabilizer, and 80 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is hydroxypropyl methylcellulose ether. (2) Mix steel slag, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 3 minutes to obtain a lightweight soil stabilizer.

[0048] Comparative Example 1 Same as Example 1, except that the amount of steel slag used is 0 parts. Specifically, the following raw materials are weighed by weight: 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water.

[0049] Comparative Example 2 Same as Example 1, except that the amount of steel slag used is 15 parts, specifically, the following raw materials are weighed by weight: 15 parts steel slag, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water.

[0050] Comparative Example 3 Same as Example 2, except that the amount of red mud used is 15 parts, specifically, the following raw materials are weighed by weight: 15 parts red mud, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water.

[0051] Comparative Example 4 Same as Example 3, except that the amount of mineral powder used is 30 parts, specifically by weight, the following raw materials are weighed: 5 parts red mud, 5 parts steel slag, 30 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water.

[0052] Comparative Example 5 Same as Example 3, except that the amount of mineral powder used is 70 parts, specifically, the following raw materials are weighed by weight: 5 parts red mud, 5 parts steel slag, 70 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water.

[0053] Comparative Example 6 Same as Example 5, except that the amount of water used is 50 parts, specifically by weight, the following raw materials are weighed: 10 parts red mud, 10 parts steel slag, 40 parts mineral powder, 20 parts gypsum, 20 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 50 parts water.

[0054] Comparative Example 7 Same as Example 6, except that the amount of water used is 120 parts, specifically by weight, the following raw materials are weighed: 10 parts red mud, 10 parts steel slag, 40 parts mineral powder, 20 parts gypsum, 20 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 120 parts water.

[0055] Comparative Example 8 Same as Example 7, except that the amount of foaming agent used is 15 parts, specifically by weight, the following raw materials are weighed: 10 parts steel slag, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 15 parts foaming agent, 2 parts foam stabilizer, and 80 parts water.

[0056] Comparative Example 9 Same as Example 3, except that the stirring time in step (2) is 10 minutes, specifically: (1) Weigh the following raw materials by weight: 5 parts red mud, 5 parts steel slag, 60 parts mineral powder, 25 parts gypsum, 10 parts carbide slag, 5 parts foaming agent, 1 part foam stabilizer, and 80 parts water. The foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate in a mass ratio of 3:1, and the foam stabilizer is hydroxypropyl methylcellulose ether. (2) Mix red mud, steel slag, mineral powder, gypsum, carbide slag, foaming agent and foam stabilizer with water and stir for 10 minutes to obtain a lightweight soil stabilizer.

[0057] Comparative Example 10 Same as Example 1, except that the foaming agent (a mixture of sodium bicarbonate and potassium aluminum sulfate) is replaced with an equal mass of hydrogen peroxide (H2O2, concentration of 30 wt.%). The preparation method is the same as in Example 1.

[0058] Comparative Example 11 Same as Example 3, except that the mineral powder is replaced with an equal amount of fly ash by mass.

[0059] Application examples The soil stabilization effect of the lightweight soil stabilizers prepared in the test examples and comparative examples: The lightweight soil stabilizers prepared in Examples 1-7 and Comparative Examples 1-11 were used for soil stabilization, specifically including the following steps: S1. Take 100g of soil sample and dry it in an 80℃ oven for 4 hours. Test the moisture content of the soil sample. S2. Experimental design: The water content of the fluid soil is 120%. Weigh 1 kg of engineering soil sample and add 20% of the dry soil mass with lightweight soil stabilizer. S3. The mixing steps are as follows: Add water and engineering soil sample to mortar mixer, mix and stir until muddy state, then add lightweight soil stabilizer, mix and stir for 5 minutes; S4. After mixing, pour the slurry into a 150mm×150mm×150mm cubic iron mold, filling each mold halfway with slurry. Wait for the lightweight soil stabilizer to foam to twice its original size, smooth the surface, cover with plastic wrap, and place in a standard curing box for 24 hours. S5. Remove the test block from the mold and place it in a standard cement-soil curing room for curing (temperature 20±5℃, humidity not less than 50%). For the first 3 days of curing, the surface of the test block needs to be kept moist by sprinkling water. After 7 days and 28 days, the test block is left to cure.

[0060] S6. Before pouring, test the fluidity of the lightweight soil stabilizer and test the unconfined compressive strength of the lightweight fluidized solidified soil at the corresponding age using a strain gauge unconfined pressure tester.

[0061] The test results of the examples are shown in Table 2, and the test results of the comparative examples are shown in Table 3.

[0062] Table 2. Test results of mechanical properties and flowability of the embodiments Table 3. Mechanical properties and flowability test results of the comparative examples. As shown in Tables 2 and 3, within the raw material ratio range of this invention (0-10 parts red mud, 0-10 parts steel slag, 40-60 parts mineral powder, 20-30 parts gypsum, 10-20 parts carbide slag, 5-10 parts foaming agent, 0.5-2 parts foam stabilizer, and 70-100 parts water), the lightweight fluidized solidified soil prepared in all embodiments exhibits balanced and excellent comprehensive performance. The 28-day unconfined compressive strength remains stable between 2.4-2.8 MPa, and the flowability is between 183-215 mm. This indicates that the specific raw material combination and ratio range of this invention can effectively synergistically achieve material lightweighting (foaming) while ensuring the necessary mechanical properties and construction fluidity for engineering filler materials. The results of Comparative Examples 4 and 5 show that when the amount of mineral powder deviates significantly from the range of this invention, the performance is severely degraded. Insufficient dosage (Comparative Example 4) resulted in insufficient gelling product formation, with a 28-day strength of only 0.3 MPa. Excessive dosage (Comparative Example 5), while achieving a later strength of 4.1 MPa, drastically reduced fluidity to 110 mm, resulting in an overly viscous slurry that lost the ease of construction characteristic of fluid soil. Comparative Example 8 showed that when the foaming agent dosage exceeded the upper limit of this invention, the 28-day compressive strength plummeted to 0.5 MPa. The 28-day strength of Comparative Example 9 (stirred for 10 minutes) was only 0.4 MPa, far lower than that of Example 3 (2.7 MPa) with the same proportions. This demonstrates that prolonged stirring affects the foam-stabilizing effect of the foam stabilizer, causing the bubbles generated by the foaming agent to burst during stirring, resulting in uneven bubble formation. After the solid waste gelling components harden, this uneven bubble formation leads to a reduction in the mechanical properties of the hardened body. Comparative Example 10 (where the foaming agent (a mixture of sodium bicarbonate and potassium aluminum sulfate) was replaced with an equal mass of hydrogen peroxide (H2O2, concentration 30 wt.%)) showed strength similar to Example 1. The difference lies in the fact that the O2 generated by hydrogen peroxide foaming poses a flammable and explosive safety hazard in enclosed construction areas such as underground spaces and tunnels. The results of Comparative Example 11 and Example 3 indicate that replacing the mineral powder in Example 3 with fly ash by an equal mass significantly reduced the mechanical properties, decreasing from 2.7 MPa to 0.2 MPa after 28 days. This suggests that replacing the mineral powder with fly ash, which has low pozzolanic activity, severely degrades the performance of the lightweight soil stabilizer. Comparative Example 1 (without steel slag) had the lowest strength (0.5 MPa) and average fluidity (154 mm). Examples 1 and 2 both achieved good performance. Example 3 even achieved the best fluidity and high strength. This indicates that red mud and steel slag are not simply fillers in this system; they provide active components, participate in early hydration, and contribute to stabilizing the bubble structure.

[0063] When the lightweight soil stabilizer of this invention is mixed with soil and water, the foaming agent in the system rapidly undergoes a dissolution and ionization process, releasing substances including Na. + K + Al 3+ SO42- HCO3 - It contains various ions, including Al. 3+ With HCO3 - A double hydrolysis reaction occurs, generating Al(OH)3 precipitate and releasing CO2 gas. These gases form bubble nuclei in the fluidized soil slurry. During this process, hydroxypropyl methylcellulose ether, as a highly efficient surfactant, rapidly forms an adsorption layer on the surface of CO2 bubbles due to its amphiphilic molecular structure, effectively reducing the free energy at the gas-liquid interface and inhibiting bubble aggregation and escape. As the reaction continues, the number of bubbles in the system increases. When the bubble density reaches a critical value, some bubbles break through the surface tension and escape. To achieve a balance between bubble generation and stability, the red mud or steel slag compounded in the lightweight solidifier plays a crucial role. These two solid wastes can form hydration products or promote the formation of hydration products in the early hydration stage, effectively hindering bubble rise and maintaining the gas-liquid-solid three-phase equilibrium state in the system. As the reaction progresses, auxiliary components such as mineral powder, gypsum, and carbide slag in the solidifier undergo depolymerization-repolymerization physicochemical reactions. Mineral powder and gypsum undergo a pozzolanic reaction and ettringite crystallization process in an alkaline environment. Meanwhile, the active calcium oxide component in carbide slag not only participates in the hydration reaction but also effectively neutralizes organic acids in the soil through ion exchange and flocculation, significantly improving the adaptability of the solidifier in high-organic-matter soils. This synergistic mechanism among the aforementioned materials ultimately optimizes and enhances the mechanical and durability properties of the lightweight solidifier.

[0064] In summary, within the scope defined by this invention, a lightweight soil stabilizer can be prepared using red mud, steel slag, mineral powder, gypsum, carbide slag, foaming agent, and foam stabilizer. This stabilizer not only possesses excellent mechanical and construction properties but also can absorb large amounts of solid waste. Using CO2 as the foaming gas not only results in a lighter weight but also eliminates flammability and explosiveness, enabling its large-scale application in enclosed or underground construction projects such as tunnels and mining subsidence areas.

[0065] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention 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 the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A lightweight soil stabilizer, characterized in that, By weight, it includes the following ingredients: 0-10 parts of red mud; 0-10 parts of steel slag; 40-60 parts of mineral powder; 20-30 parts plaster; 10-20 parts of calcium carbide slag; 5-10 parts of foaming agent; Foam stabilizer 0.5-2 parts; 70-100 parts water; Wherein, the red mud and the steel slag are not both 0 by weight, and the foaming agent is a mixture of sodium bicarbonate and potassium aluminum sulfate.

2. The lightweight soil stabilizer according to claim 1, characterized in that, The mass ratio of sodium bicarbonate to potassium aluminum sulfate in the foaming agent is 3:

1.

3. The lightweight soil stabilizer according to claim 1, characterized in that, The foam stabilizer is selected from at least one of hydroxypropyl methylcellulose ether, dodecyl dimethyl ammonium oxide, and coconut oil diethanolamide.

4. The lightweight soil stabilizer according to claim 1, characterized in that, The mineral powder is S95 grade mineral powder with a particle size ≤20μm.

5. The lightweight soil stabilizer according to claim 1, characterized in that, The gypsum is at least one of industrial desulfurization gypsum, phosphogypsum, and titanium gypsum.

6. The lightweight soil stabilizer according to claim 1, characterized in that, The CaO content in the carbide slag is greater than 50%.

7. A method for preparing a lightweight soil stabilizer as described in any one of claims 1-6, characterized in that, Includes the following steps: Weigh each raw material according to the specified weight proportions, mix the raw materials, stir evenly, and obtain the lightweight soil stabilizer.

8. The method for using a lightweight soil stabilizer according to claim 7, characterized in that, The stirring time shall not exceed 5 minutes.

9. A lightweight, fluidized, solidified soil, characterized in that, The lightweight soil stabilizer according to any one of claims 1-6, wherein the method for preparing the lightweight fluidized stabilized soil comprises the following steps: (1) Mix the engineering soil sample with water to obtain mud; (2) Add the lightweight soil stabilizer according to any one of claims 1-6 to the mud, mix and stir evenly to obtain a slurry; (3) The slurry is poured into shape, foamed, and cured to obtain the lightweight fluid solidified soil.

10. The application of a lightweight soil stabilizer as described in any one of claims 1-6 and / or a lightweight fluidized solidified soil as described in claim 9 in soft soil foundation treatment, slope repair, roadbed load reduction filling, bridge abutment backfilling, or tunnel goaf filling projects.

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