Preparation method of multi-active-center synergistic flow-state solidified soil
By combining asynchronous temperature field treatment, thermal activation pretreatment and low-temperature passivation pretreatment with thermal shock mixing, the problems of low early strength, low material utilization and low synergistic efficiency of traditional fluidized solidified soil in engineering waste soil with high moisture content are solved, and efficient and rapid solidified soil preparation is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional methods for preparing fluidized solidified soil have several drawbacks when dealing with engineering waste soil with high moisture content, including slow early strength development, low utilization rate of solidification materials, high cost, and low synergistic efficiency of multiple active centers.
A multi-active-center synergistic fluidized solidified soil preparation method is adopted. By asynchronously treating key active components with a temperature field, including thermal activation pretreatment and low-temperature passivation pretreatment, combined with thermal shock mixing, an asynchronous temperature field and reaction field are created to achieve efficient and rapid solidification.
Under conventional equipment conditions, efficient and rapid solidification of sludge with high water content was achieved, significantly improving the synergistic effect of multiple active centers, reducing production costs, and ensuring rapid development of early strength and stable growth of later strength.
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Figure CN121779078A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials technology, and in particular to a method for preparing multi-active-center synergistic fluidized solidified soil. Background Technology
[0002] Fluidized solidified soil is a slurry material with certain fluidity and later strength formed by mixing engineering waste soil, solidification materials, water and admixtures in a certain proportion and stirring. It is widely used in engineering fields such as roadbed backfilling and pipe gallery backfilling. Its core technology lies in the physical and chemical reaction between the active components (such as cement, slag, etc.) in the solidification materials and water and soil to generate hydration products with cementing ability, thereby giving the mixture strength.
[0003] Traditional methods for preparing fluidized solidified soil typically involve mixing all raw materials (including soil, all types of cementitious materials, water, and admixtures) in a mixer at room temperature all at once. This method has significant drawbacks when dealing with engineering waste soil with high moisture content (e.g., greater than 40%), especially river silt and tunnel boring machine silt.
[0004] Slow early strength development: The large amount of free water in the sludge dilutes the initial concentration of the cementitious material, and the low temperature environment (especially winter construction) further inhibits the hydration reaction rate of the main active centers represented by cement, resulting in a long solidification time and extremely low early strength (such as 1-day and 3-day strength), which cannot meet the requirements of rapid construction turnover.
[0005] Low utilization rate and high cost of curing materials: In order to achieve the design strength under adverse conditions, it is often necessary to significantly increase the amount of fast-hardening materials such as cement; this not only increases the cost, but also the excessive amount of cement can easily lead to increased shrinkage of the cured body, resulting in the risk of cracking.
[0006] Low efficiency of multi-active-center synergy: The traditional "one-pot" mixing method causes cementitious materials with different reactivity (such as fast-hardening cement and slow-reacting slag) to start reacting simultaneously under the same temperature and concentration environment; the heat of hydration of fast-reacting materials may be quickly absorbed by a large amount of water and cold soil in the system, which cannot effectively stimulate slow-reacting materials; while slow-reacting materials may hinder the effective hydration space of fast-reacting materials, resulting in competition or inhibition between active centers, and failing to achieve temporal optimization synergy.
[0007] Therefore, to address the above problems, a method for preparing multi-active-center synergistic fluidized solidified soil is proposed. By creating asynchronous temperature and reaction fields, key active components are pretreated differently, thereby achieving efficient and rapid solidification of high-moisture-content sludge under conventional equipment conditions and significantly improving the synergistic effect of multiple active centers. Summary of the Invention
[0008] In order to overcome the problems of slow early strength development, low utilization rate of solidification materials, high cost, and low synergistic efficiency of multiple active centers in the traditional preparation method of fluidized solidified soil when dealing with engineering waste soil with high water content.
[0009] The technical solution of this invention is: a method for preparing multi-active-center synergistic fluidized solidified soil, comprising the following steps:
[0010] S1: Thermal activation pretreatment of core active components: The first part of the cementitious material is heated at a temperature of 80℃ to 120℃ to obtain thermally activated active material;
[0011] S2: Low-temperature passivation pretreatment of the main matrix: The engineering waste soil, the second part of the cementitious material and water are mixed and stirred for the first time, while the temperature of the mixing system is controlled within the range of 5℃ to 15℃ to obtain a low-temperature matrix slurry.
[0012] S3: Thermal shock mixing: The thermally activated active material is added to the low-temperature matrix slurry and stirred for the second time to mix the thermally activated active material with the low-temperature matrix slurry to obtain a fluidized solidified soil mixture;
[0013] The first part of the cementitious material includes at least one of sulfoaluminate cement, rapid-hardening cement, or mechanically activated steel slag powder.
[0014] Preferably, this method involves independently thermally activating a small amount of key fast-hardening active materials to convert them into thermally activated active materials with high reaction potential; secondly, actively performing low-temperature passivation pretreatment on the main system containing most of the cementitious materials and all the waste soil to create a low-temperature, stable, and inert reaction environment; and finally, introducing the high-temperature thermally activated active materials into the low-temperature reaction environment and achieving the combination of the two through thermal shock mixing.
[0015] Preferably, in step S1, the duration of the heat treatment is 3 to 10 minutes.
[0016] Preferably, the first portion of cementitious material accounts for 20% to 40% of the total mass of all cementitious materials.
[0017] Preferably, in step S2, the water used to mix with the engineering waste soil and the second part of the cementitious material is cooling water with a temperature below 10°C or an ice-water mixture containing ice chips.
[0018] Preferably, in step S2, the first stirring speed is 30 r / min to 60 r / min, and the stirring time is 3 minutes to 5 minutes.
[0019] Preferably, in step S3, the second stirring speed is 80 r / min to 150 r / min, and the stirring time is 1 minute to 3 minutes.
[0020] Preferably, in step S3, when the thermally activated active material is added to the low-temperature matrix slurry, its own temperature is not lower than 60°C.
[0021] Preferably, the second part of the cementitious material includes at least one of slag powder, fly ash, metakaolin, or ordinary silicate cement.
[0022] Preferably, the excavated soil is river silt, shield tunnel silt, or dredged bottom mud with a moisture content of not less than 40%.
[0023] Preferably, in step S2, a chemical admixture is added to the low-temperature matrix slurry, the chemical admixture including at least one of a water-reducing agent, a retarder, or a water-retaining agent.
[0024] The beneficial effects of this invention are:
[0025] This invention utilizes an asynchronous temperature field activation process, employing thermally activated active materials as dispersed high-temperature "thermal cores" and rapid "reaction cores." These are triggered instantaneously during mixing, rapidly generating a large number of early hydration products in local micro-regions, thus constructing an early strength framework. Meanwhile, the slow-reacting materials in the low-temperature matrix slurry avoid ineffective pre-hydration. Their reaction is gradually awakened and accelerated by the hydration heat generated by the "thermal cores" and the alkaline environment, contributing to a stable increase in later strength. The entire system thus forms a reaction process that progresses from point to surface, from fast to slow, and with gradient synergy. This preparation method effectively solves the problems of low early strength and slow setting of high-moisture-content sludge solidification using only a conventional mixing station and a simple heating device, reducing the production cost of high-performance fluidized solidified soil and achieving efficient synergy of multiple active centers in time and space. Attached Figure Description
[0026] Figure 1 The diagram shows the steps of the multi-active-center synergistic fluidized solidified soil preparation method of the present invention. Detailed Implementation
[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0028] Example 1
[0029] Please see Figure 1 This invention provides an embodiment: a method for preparing multi-active-center synergistic fluidized solidified soil, comprising the following steps:
[0030] S1: Thermal activation pretreatment of core active components: The first part of the cementitious material is heated at a temperature of 80℃ to 120℃ to obtain thermally activated active material;
[0031] S2: Low-temperature passivation pretreatment of the main matrix: The engineering waste soil, the second part of the cementitious material and water are mixed and stirred for the first time, while the temperature of the mixing system is controlled within the range of 5℃ to 15℃ to obtain a low-temperature matrix slurry.
[0032] S3: Thermal shock mixing: The thermally activated active material is added to the low-temperature matrix slurry and stirred a second time to mix the thermally activated active material with the low-temperature matrix slurry to obtain a fluidized solidified soil mixture;
[0033] The first part of the cementitious material includes at least one of sulfoaluminate cement, rapid-hardening cement, or mechanically activated steel slag powder.
[0034] This method involves independently thermally activating a small amount of key fast-hardening active materials to transform them into thermally activated active materials with high reaction potential. Secondly, the main system, which includes most of the cementitious materials and all the waste soil, undergoes an active low-temperature passivation pretreatment to create a low-temperature, stable, and inert reaction environment. The high-temperature thermally activated active materials are then introduced into the low-temperature reaction environment and mixed through thermal shock to achieve the combination of the two.
[0035] In step S1, the principle of heating the first part of the cementitious material is as follows: by drying and activating this part of the temperature-sensitive active material at medium and low temperatures, the adsorbed water on its surface can be removed, the surface energy of the particles can be increased, and the crystal structure of some mineral phases (such as anhydrous calcium sulfoaluminate in sulfoaluminate cement) can be in a "metastable" or "activated" state. This pretreatment does not trigger a substantial hydration reaction, but it reduces the activation energy of the subsequent hydration reaction, so that it can start rapidly and react violently after contacting water, providing the initial hydration driving force for the entire system.
[0036] Furthermore, in step S1, the heating treatment lasts for 3 to 10 minutes; this duration is sufficient to ensure that heat is fully transferred to the interior of the material particles to complete effective thermal activation, while avoiding excessive time that could lead to energy waste or cause overheating and decomposition of certain components.
[0037] Furthermore, the first part of the cementitious material accounts for 20% to 40% of the total mass of all cementitious materials; this proportion ensures that a sufficient number of "thermal nuclei" are dispersed throughout the system in step S3 to form an effective early strength skeleton; if the proportion is too low, the "thermal nuclei" effect will be insufficient; if the proportion is too high, the economy will decrease and the workability may be affected due to the excessive concentration of early reactions.
[0038] Furthermore, in step S2, the water used to mix with the excavated soil and the second part of the cementitious material is cooling water with a temperature below 10°C or an ice-water mixture containing ice chips; using low-temperature water is a key means of actively reducing the temperature of the main mixing system to 5°C to 15°C; the low-temperature environment is not for freezing, but for "passivating" the second part of the cementitious material (usually slow-reacting materials such as slag and fly ash or ordinary silicate cement); the low temperature significantly inhibits the prehydration of these materials during the mixing and transportation process, keeping them chemically inert in the early stage of mixing, thereby ensuring that the slurry has good fluidity and a sufficiently long workable time.
[0039] Furthermore, in step S2, the first stirring speed is 30 r / min to 60 r / min, and the stirring time is 3 minutes to 5 minutes. This mild stirring condition aims to achieve a thorough and uniform mixing of the engineering waste soil, cementitious materials and low-temperature water to form a homogeneous and stable low-temperature matrix slurry, while avoiding excessive heat generated by vigorous stirring, which would affect the low-temperature passivation effect.
[0040] Furthermore, in step S3, the second stirring speed is 80 r / min to 150 r / min, and the stirring time is 1 minute to 3 minutes; the stirring intensity in this stage is significantly higher than that in the first stirring; the purpose is, on the one hand, to achieve rapid and uniform dispersion of the thermally activated active material in the low-temperature matrix slurry; on the other hand, the shear force generated by high-speed stirring and the huge temperature difference between the high-temperature particles (thermally activated active material) and the low-temperature slurry work together to produce a "thermal shock" effect.
[0041] Furthermore, in step S3, when the thermally activated active material is added to the low-temperature matrix slurry, its own temperature is not lower than 60°C; the high-temperature particles (above 60°C) come into instantaneous contact with the low-temperature slurry (5-15°C), generating a severe temperature gradient and thermal stress in the micro-region on the particle surface; the thermal stress helps to break up any soil particles or cementitious material clusters that may exist in the slurry, promoting further dispersion of the material; the trace amounts of moisture adsorbed on the surface of the high-temperature particles may vaporize instantaneously, forming a micro-vapor film, further improving the wettability and dispersibility of the particle surface; the high-temperature environment in the local micro-region provides the optimal temperature conditions required for the thermally activated active material's hydration reaction, allowing the hydration reaction to occur instantaneously.
[0042] Furthermore, the second part of the cementitious material includes at least one of slag powder, fly ash, metakaolin, or ordinary silicate cement; these materials typically have a slow hydration reaction or are relatively insensitive to temperature, making them suitable as components of the main matrix; they are "protected" in the initial low-temperature environment, and then, under the gradual stimulation of the heat of hydration released by the "thermonucleus" and the alkaline environment provided, they begin to participate in the reaction continuously and stably, contributing to the later strength, and achieving good connection and synergy with the "thermonucleus" material in the reaction sequence.
[0043] Furthermore, the excavated soil is river silt, shield tunnel silt, or dredged bottom sediment with a moisture content of not less than 40%. The method of this invention is specifically designed for such difficult-to-treat excavated soil with high moisture content, low strength, and often containing interfering components such as organic matter. Traditional single mixing methods are ineffective for such soils, while the "thermal core-cold base" asynchronous treatment mode of this invention can effectively overcome its adverse effects.
[0044] Furthermore, in step S2, a chemical admixture is added to the low-temperature matrix slurry. The chemical admixture includes at least one of a water-reducing agent, a retarder, or a water-retaining agent. Adding the admixture during the low-temperature passivation stage allows for more precise control of the rheological properties of the low-temperature matrix slurry (e.g., improving fluidity through a water-reducing agent) and setting time (e.g., further ensuring workability through a retarder), making the control of the entire preparation process more flexible and precise.
[0045] Through the above steps, this invention utilizes an asynchronous temperature field activation process, using thermally activated active materials as dispersed high-temperature "thermal cores" and rapid "reaction cores." These are triggered instantly during mixing, rapidly generating a large number of early hydration products in local micro-regions, thus constructing an early strength framework. Meanwhile, the slow-reacting materials in the low-temperature matrix slurry avoid ineffective pre-hydration. Their reaction is gradually awakened and accelerated by the hydration heat generated by the "thermal cores" and the alkaline environment, contributing to a stable increase in later strength. The entire system thus forms a reaction process that progresses from point to surface, from fast to slow, and with gradient synergy. This preparation method effectively solves the problems of low early strength and slow setting of high-moisture-content sludge solidification using only a conventional mixing station and a simple heating device, reducing the production cost of high-performance fluidized solidified soil and achieving efficient synergy of multiple active centers in time and space.
[0046] Example 2
[0047] Optionally, this embodiment provides a basic preparation method for multi-active-center synergistic fluidized solidified soil.
[0048] Step S1: Thermal activation pretreatment of core active components
[0049] Sulfoaluminate cement was used as the first batch of cementitious material, accounting for 30% of the total mass of all cementitious materials required for this batch. This portion of sulfoaluminate cement was put into a simple heating drum equipped with a hot air circulation system. The equipment was started, and the material was heated continuously for 5 minutes at a hot air temperature of 100°C. During the treatment, the material was constantly turned over to ensure uniform heating. After treatment, the material was immediately removed, and the temperature of the material was measured to be approximately 85°C, thus obtaining thermally activated active material. The purpose of this step is to remove adsorbed water from the surface of the material, increase its surface energy, and bring its crystal structure to a highly active metastable state.
[0050] Step S2: Low-temperature passivation pretreatment of the substrate
[0051] River silt with a moisture content of 55% was prepared as excavated soil for the project. In the main mixer (twin-shaft forced mixer), all the required amount of river silt was first added. Then, slag powder was added as the second part of the cementitious material, accounting for 70% of the total mass of the cementitious material. Next, sufficient cooling water at 8°C was added to ensure that the total water-cement ratio (the ratio of total water to the total mass of cementitious material) reached the design value of 0.45. The mixer was started, and the mixture was first stirred at 40 r / min for 4 minutes. During the stirring process, the temperature of the entire mixing system was stabilized at approximately 10°C through the addition of cooling water and gentle stirring, thereby obtaining a uniform, fluid, low-temperature matrix slurry. The low-temperature environment effectively inhibited the early hydration reaction of the slag powder.
[0052] Step S3: Thermal Shock Mixing
[0053] Just before the end of step S2 mixing, the thermally activated active material prepared in step S1, still at a temperature of about 80°C, is rapidly and uniformly added to the low-temperature matrix slurry in the main mixer; the mixer speed is immediately increased to 120 r / min for a high-intensity, short-duration second mixing, lasting 2 minutes; during this process, the high-temperature sulfoaluminate cement particles and the low-temperature sludge-slag slurry are violently mixed, producing a significant thermal shock effect: the high-temperature particles instantly heat the water and slurry in the surrounding micro-area, generating local thermal stress and micro-disturbance, promoting the final dispersion of the particles; at the same time, the local high-temperature environment strongly stimulates the rapid hydration reaction of sulfoaluminate cement; after mixing, a uniform fluidized solidified soil mixture is obtained, with its overall temperature equilibrated to about 25°C; the mixture is cast into shape and cured under standard curing conditions (temperature 20±2°C, relative humidity above 95%).
[0054] Example 3
[0055] Optionally, this embodiment targets high-moisture-content silt generated during shield tunneling, emphasizing rapid early strength formation, and is suitable for emergency backfilling or rapid turnover construction scenarios.
[0056] Step S1: Thermal activation pretreatment of core active components
[0057] Rapid-hardening sulfoaluminate cement was selected as the first part of the cementitious material, accounting for 25% of the total mass of all cementitious materials (the sum of rapid-hardening sulfoaluminate cement and fly ash); it was placed in a hot air drying equipment and heated at 110℃ for 8 minutes; after being taken out, the material temperature was measured to be 90℃, and it was put into use.
[0058] Step S2: Low-temperature passivation pretreatment of the substrate
[0059] Take shield tunnel sludge with a moisture content of 60%; in the main mixer, add all the shield tunnel sludge and 75% of the total mass of Class II fly ash (second part of the cementitious material); to enhance the low-temperature passivation effect, an ice-water mixture containing fine ice chips is used as the mixing water, and the system temperature is controlled after addition; stir at 35 r / min for 5 minutes; during this process, the temperature of the mixed slurry is precisely controlled at about 7℃ through the heat absorption of the melting ice chips, forming a low-temperature, high-fluidity matrix; to improve the slurry performance, 0.5% of the total mass of the cementitious material is also added in this step as a polycarboxylate superplasticizer;
[0060] Step S3: Thermal Shock Mixing
[0061] The rapidly activated quick-hardening cement, with a temperature of approximately 85°C, was quickly added to the aforementioned low-temperature slurry. A high-speed mixing mode was then activated, with the speed adjusted to 150 r / min, for a second, vigorous mixing process lasting 1.5 minutes. The extremely high shear rate combined with the significant temperature difference (approximately 78°C) resulted in an extreme "thermal shock," highly activating the quick-hardening cement upon contact with the slurry. Immediate testing after mixing revealed an initial flowability of 280 mm, with a flowability loss rate of less than 15% within 30 minutes, demonstrating excellent workability. After pouring, its compressive strength within one day reached the level of the traditional three-day strength.
[0062] Example 3
[0063] Optionally, this embodiment focuses on preparing fluidized solidified soil using industrial solid waste under low ambient temperature conditions.
[0064] Step S1: Thermal activation pretreatment of core active components
[0065] Steel slag powder (specific surface area ≥450 m² / kg) pre-milled and activated by a vertical mill was used as the first part of the cementitious material, accounting for 20% of the total mass of all cementitious materials (the sum of steel slag powder and ordinary Portland cement P·O 42.5); it was treated in hot air at 95℃ for 3 minutes, and the temperature after removal was about 70℃; thermal activation further stimulated the potential activity of the steel slag.
[0066] Step S2: Low-temperature passivation pretreatment of the substrate
[0067] The construction conditions were simulated at an ambient temperature of 5℃. Construction waste with a moisture content of 45% and ordinary Portland cement P·O 42.5 (part two cementitious materials), comprising 80% of the total mass of cementitious materials, were added to an insulated mixing tank. Pre-cooled water to 3℃ was used for mixing. The first mixing was performed at 50 r / min for 3 minutes. Despite the use of cold water, the slurry temperature after mixing was approximately 12℃ due to the initial exothermic reaction of cement hydration, remaining within the effective low-temperature passivation range. To extend the working time, sodium gluconate, comprising 0.1% of the total mass of cementitious materials, was added as a retarder.
[0068] Step S3: Thermal Shock Mixing
[0069] The 70°C thermally activated steel slag powder was added to a 12°C low-temperature matrix slurry; a second stirring was performed at 100 r / min for 3 minutes. In this embodiment, the thermally activated steel slag powder not only provides an early reaction point as a "thermal core," but its components, such as f-CaO, are more easily and quickly dissolved under thermal shock, forming a high-alkalinity environment with Ca(OH)2 produced by cement hydration. This environment can more fully stimulate further cement hydration and the remaining activity of the steel slag itself. After curing, its 28-day strength was significantly improved compared to the control group without thermal activation treatment, achieving efficient utilization of industrial solid waste.
[0070] Example 4
[0071] Optionally, this embodiment focuses on demonstrating how to obtain ultra-high fluidity solidified soil by adjusting process parameters, which is suitable for filling narrow spaces or complex structures.
[0072] Step S1: Thermal activation pretreatment of core active components
[0073] Sulfoaluminate cement was used as the first cementing material, accounting for 35% of all cementing materials (the sum of sulfoaluminate cement and metakaolin); it was heated at 85°C for 6 minutes to obtain a heat-activated material with a temperature of about 75°C.
[0074] Step S2: Low-temperature passivation pretreatment of the substrate
[0075] The dredged sludge with a moisture content of 50% was treated. Added to the mixer along with the sludge was metakaolin (part two cementitious materials), comprising 65% of the total mass of the cementitious materials. The mixing water was ice water at 5°C. The mixing was carried out at a relatively low speed of 30 r / min for 4.5 minutes to ensure the formation of an extremely uniform slurry with suitable viscosity at low temperatures (final slurry temperature approximately 9°C), avoiding the introduction of excessive air bubbles. An additional 0.8% high-efficiency water-reducing agent and 0.05% water-retaining agent (hydroxypropyl methylcellulose) were added to the total mass of the cementitious materials, giving the low-temperature matrix slurry excellent fluidity and stability even at a low water-cement ratio (0.40).
[0076] Step S3: Thermal Shock Mixing
[0077] After adding the thermally activated material to the low-temperature slurry, a second stirring was performed at a speed of 80 r / min for 2.5 minutes. This speed was sufficient to ensure uniform mixing while avoiding excessive shear that could lead to loss of fluidity. Tests showed that the initial fluidity of the prepared solidified soil mixture exceeded 300 mm, and there was almost no collapse loss within 2 hours, meeting the construction requirements for long-distance pumping and complex filling. Moreover, its early strength development was not adversely affected by the high fluidity.
[0078] As can be seen from the above embodiments, the asynchronous temperature field activation method of the present invention combines three steps: thermal activation of the core active material, low-temperature passivation of the main matrix, and final thermal shock mixing. This method successfully achieves efficient solidification of high-moisture-content and difficult-to-treat engineering waste soil on conventional equipment. Whether the goal is to pursue early strength (as in Example 3), low-temperature environment construction (as in Example 4), or ultra-high fluidity (as in Example 5), optimization can be achieved by adjusting the specific material types, proportions, temperatures, and mixing parameters of each step. This demonstrates the significant advantages of the present invention in terms of flexibility, efficiency, and strong synergy.
[0079] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.
Claims
1. A method for preparing multi-active-center synergistic fluidized solidified soil, characterized in that: Includes the following steps: S1: Thermal activation pretreatment of core active components: The first part of the cementitious material is heated at a temperature of 80℃ to 120℃ to obtain thermally activated active material; S2: Low-temperature passivation pretreatment of the main matrix: The engineering waste soil, the second part of the cementitious material and water are mixed and stirred for the first time, while the temperature of the mixing system is controlled within the range of 5℃ to 15℃ to obtain a low-temperature matrix slurry. S3: Thermal shock mixing: The thermally activated active material is added to the low-temperature matrix slurry and stirred for the second time to mix the thermally activated active material with the low-temperature matrix slurry to obtain a fluidized solidified soil mixture; The first part of the cementitious material includes at least one of sulfoaluminate cement, rapid-hardening cement, or mechanically activated steel slag powder.
2. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: In step S1, the heating treatment lasts for 3 to 10 minutes.
3. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: The first part of the cementitious material accounts for 20% to 40% of the total mass of all cementitious materials.
4. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: In step S2, the water used to mix with the engineering waste soil and the second part of the cementitious material is cooling water with a temperature below 10°C or an ice-water mixture containing ice chips.
5. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: In step S2, the first stirring speed is 30 r / min to 60 r / min, and the stirring time is 3 minutes to 5 minutes.
6. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: In step S3, the second stirring speed is 80 r / min to 150 r / min, and the stirring time is 1 minute to 3 minutes.
7. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: In step S3, when the thermally activated active material is added to the low-temperature matrix slurry, its own temperature is not lower than 60°C.
8. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: The second part of the cementitious material includes at least one of slag powder, fly ash, metakaolin, or ordinary Portland cement.
9. The method for preparing multi-active-center synergistic fluidized solidified soil according to claim 1, characterized in that: The excavated soil from the project is river silt, shield tunnel silt, or dredged bottom mud with a moisture content of not less than 40%.
10. A method for preparing multi-active-center synergistic fluidized solidified soil according to any one of claims 1-9, characterized in that: In step S2, a chemical admixture is added to the low-temperature matrix slurry, the chemical admixture including at least one of water-reducing agent, retarder, or water-retaining agent.