Industrial solid waste-based soft soil curing repair material and preparation method thereof

Abstract

The application discloses a kind of soft soil solidification repair materials based on industrial solid waste and preparation method thereof, belong to the field of soil mechanics and water and soil conservation engineering materials. In mass fraction, the soft soil solidification repair material includes 30~40 portions of vanadium slag-boron mud composite material, 25~35 portions of municipal sludge-dredged silt composite material, 15~20 portions of waste ceramic powder, 5~8 portions of modified steel slag powder, 4~6 portions of metakaolin-silica ash composite material, 3~5 portions of alkali activator, 2~6 portions of biological mineralization bacterium agent, 2~3 portions of nano composite adsorbent, 1~2 portions of amphoteric polymer flocculant, 1.5~2.5 portions of anti-cracking-water-retaining composite agent, 1.5~2 portions of ecological repair agent;The mass of mixing water is 22%~28% of the total mass of the above-mentioned substances. The ecological soft soil solidification repair material provided by the application realizes the efficient solidification of the material to soft soil, heavy metal stabilization and ecological repair multiple functions through the synergistic activation of multiphase materials, the composite regulation of functional additives and the optimization of innovative process.

Description

Technical Field

[0001] This invention belongs to the field of soil mechanics and soil and water conservation engineering materials technology, specifically relating to a soft soil solidification and remediation material based on industrial solid waste and its preparation method. Background Technology

[0002] Soft soil foundations refer to foundations composed of silt, silty soil, and fill soil, characterized by high natural water content, large void ratio, high compressibility, and low shear strength. Such foundations are prone to significant settlement and deformation when bearing the loads of buildings or structures, posing a threat to engineering safety. Therefore, specialized treatment technologies are needed to improve their engineering properties. Ecological restoration engineering, on the other hand, targets polluted, damaged, or degraded ecological environments, employing physical, chemical, and biological methods to restore or rebuild the structure and function of the ecosystem, thereby improving the quality of the ecological environment. Common applications include contaminated soil remediation, damaged wetland restoration, and mine ecological restoration.

[0003] In soft soil foundation treatment and ecological restoration projects, traditional solidification materials mostly rely on traditional cementitious materials such as cement and lime, which have problems such as high carbon emissions, low solid waste utilization rate, and poor ecological compatibility. While existing technologies have attempted to prepare solidification materials using solid wastes such as sludge and slag, they generally suffer from the following limitations: the solidification system is singular, relying heavily on the cementing effect of a single component, resulting in uneven strength development; the stabilization effect on heavy metals is limited, often employing single adsorbent materials, making it difficult to adapt to complex polluted environments; ecological functions are lacking, failing to consider the promoting effect of the solidified material on the surrounding soil microecology and plant growth; and the preparation methods are simple, failing to achieve synergistic activation and uniform mixing of multiphase materials.

[0004] To address the aforementioned issues, developing a novel material with high solid waste content, multiphase synergistic solidification, and both heavy metal stabilization and ecological restoration functions is of great significance for promoting the resource utilization of solid waste and upgrading water and soil conservation engineering technologies. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing soft soil solidification materials, such as low solid waste utilization rate, single solidification system, insufficient heavy metal stabilization effect, and poor ecological compatibility. It provides a soft soil solidification and remediation material based on industrial solid waste and its preparation method. Through the synergistic activation of multiphase materials, the composite regulation of functional additives, and the optimization of innovative processes, the material achieves multiple functions of efficient solidification, heavy metal stabilization, and ecological restoration of soft soil.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a soft soil solidification and remediation material based on industrial solid waste, comprising, by weight, 30-40 parts vanadium slag-boron mud composite, 25-35 parts municipal sludge-dredging sludge composite, 15-20 parts waste ceramic powder, 5-8 parts modified steel slag powder, 4-6 parts metakaolin-silica fume composite, 3-5 parts alkali activator, 2-6 parts biomineralizing agent, 2-3 parts nanocomposite adsorbent, 1-2 parts amphoteric polymer flocculant, 1.5-2.5 parts crack-resistant-water-retaining composite agent, and 1.5-2 parts ecological restoration agent; the mixing water accounts for 22%-28% of the total mass of the above substances.

[0008] The preparation method of the vanadium slag-boron mud composite material includes:

[0009] Vanadium slag and boron mud were mixed at a mass ratio of (2~4):1 to obtain a first mixture. Sodium carbonate and sodium fluoride were added to the first mixture, and the mixture was calcined at 850~950℃ to obtain a vanadium slag-boron mud composite material. The total mass of sodium carbonate and sodium fluoride was 6%~8% of the mass of the first mixture, and the mass ratio of sodium carbonate to sodium fluoride was (2~3):1.

[0010] The preparation method of the municipal sludge-dredging sludge composite material includes:

[0011] Municipal sludge and dredged sludge were mixed at a mass ratio of (2~3):1 and then subjected to plasma treatment to obtain a municipal sludge-dredged sludge composite material; the moisture content of the municipal sludge was 50%~60%; the mass fraction of organic matter in the dredged sludge was 15%~20%, and the moisture content was 60%~70%; the mass fraction of organic matter in the municipal sludge-dredged sludge composite material was 20%~30%.

[0012] The waste ceramic powder contains 35% to 45% Al2O3 and 50% to 60% SiO2 by mass.

[0013] The method for preparing the modified steel slag powder includes:

[0014] After being quenched in water and magnetically separated to remove iron, the converter steel slag is calcined at 1050~1150℃ to obtain steel slag powder. The steel slag powder is then modified with a silane coupling agent to obtain modified steel slag powder.

[0015] The preparation method of the metakaolin-silica composite material includes:

[0016] Metakaolin is obtained by calcining kaolin at 800~900℃;

[0017] Metakaolin, silica fume and nano TiO2 are mixed to obtain metakaolin-silica fume composite material; the mass ratio of metakaolin to silica fume is (3~4):1, and the mass of nano TiO2 accounts for 2%~3% of the total mass of metakaolin and silica fume.

[0018] The method for preparing the alkaline activator includes:

[0019] An alkaline activator is obtained by mixing 30%–40% lithium hydroxide, 40%–50% water glass, 10%–20% sodium pyrophosphate and 5%–10% tartaric acid by weight percentage.

[0020] The preparation method of the biomineralizing bacterial agent includes:

[0021] Bacillus pasteurellii was cultured in LB medium at 20-30°C to obtain a bacterial suspension with a concentration of 10. 8 ~10 9 CFU / mL;

[0022] The bacterial solution and urease were mixed at a volume ratio of (4~6):1 to obtain the biomineralizing bacterial agent.

[0023] The preparation method of the nanocomposite adsorbent includes:

[0024] Montmorillonite, nano-hydroxyapatite, and graphene oxide were added to water at a mass ratio of (2~3):(1~2):1 to obtain a second mixture. The second mixture was then vacuum dried at 60~70℃ and ground to obtain a nano-composite adsorbent.

[0025] The preparation method of the amphoteric polymeric flocculant includes:

[0026] Acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride were added to water at a molar ratio of (3~4):(1~2):1 to obtain a third mixture. An initiator was added to the third mixture, and polymerization was initiated at 50~60℃ to obtain an amphoteric polymer flocculant. The mass of the initiator added was 0.1%~0.2% of the total mass of acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride.

[0027] The preparation method of the crack-resistant and water-retaining composite agent includes:

[0028] Hydroxypropyl methylcellulose and polyvinyl alcohol fiber were mixed at a mass ratio of (3~5):1 to obtain an anti-crack and water-retaining composite agent.

[0029] The preparation method of the ecological restoration agent includes:

[0030] An ecological restoration agent is prepared by mixing humic acid, slow-release compound fertilizer and arbuscular mycorrhizal fungal spores at a mass ratio of (3~5):(2~3):1.

[0031] The mixing water is an aqueous solution of calcium nitrate with a mass fraction of 0.5% to 1%.

[0032] This invention also provides a method for preparing the above-mentioned soft soil solidification and remediation material based on industrial solid waste, comprising:

[0033] The main mixture is prepared by mixing vanadium slag-boron mud composite material, municipal sludge-dredging sludge composite material, waste ceramic powder and mixing water.

[0034] Modified steel slag powder, metakaolin-silica composite material, alkali activator and mixing water are added to the main mixture to obtain a solidified mixture;

[0035] After adding nanocomposite adsorbent, amphoteric polymer flocculant, crack-resistant and water-retaining composite agent, ecological restoration agent and mixing water to the solidified mixture and mixing evenly, biomineralizing bacteria are added to obtain soft soil solidification and repair material.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] This invention addresses the issue of soft soil solidification by using multi-source industrial solid waste—vanadium slag-boron mud composite, municipal sludge-dredging sludge composite, and waste ceramic powder—as core raw materials. Under the action of an alkaline activator, these materials generate gel products, constructing the framework of the repair material and improving the density and impermeability of the solidified substrate. Furthermore, through the synergistic effect of modified steel slag powder, metakaolin-silica fume composite multiphase materials, and the alkaline activator, the early strength of the solidified body is rapidly enhanced, meeting the short-term requirements of foundation bearing capacity during construction and avoiding potential engineering hazards caused by foundation settlement. Simultaneously, the hydration reaction ensures the later-stage strength of the solidified body. The formula ensures continuous and stable growth, enhancing the long-term stability of the solidified substrate, reducing settlement and deformation, and extending the service life of the project. Furthermore, through the use of various functional additives such as nanocomposite adsorbents, amphoteric polymer flocculants, crack-resistant and water-retaining composite agents, and ecological restoration agents, it effectively stabilizes multiple heavy metals in complex polluted environments through adsorption, complexation, and precipitation mechanisms. This significantly reduces the migration and bioavailability of heavy metal ions in the soil, effectively blocking heavy metals from entering the ecological chain through groundwater and plant absorption, ensuring the safety of surrounding water bodies, soil, and organisms, and providing a guarantee for the safe development and utilization of polluted soft soil areas. Simultaneously, the formula considers the impact of the solidified material on soil microecology and plant growth. By adding biocompatible ecological restoration agents, it improves the soil surrounding the solidified body while achieving soft soil solidification and heavy metal stabilization, providing a suitable living environment for soil microorganisms, promoting the reproduction and activity of beneficial microbial communities, and thus promoting the restoration of ecological processes such as soil organic matter decomposition and nutrient cycling, achieving a synergistic effect between engineering and ecological benefits. Furthermore, the composite material provided by this invention makes full use of industrial waste such as slag and sludge, avoiding secondary pollution from solid waste, and also reduces dependence on natural resources such as cement and lime, which meets the requirements of green and low-carbon development under the current "dual carbon" goal.

[0038] The preparation of the composite curing material of this invention is divided into three stages. First, the main substrate is mixed to ensure the uniformity of the substrate. Then, the composite curing material is dispersed in the main substrate to form a three-dimensional reinforcing skeleton prototype, thereby improving the structural support of the material. Finally, functional additives and biomineralizing agents are added to control the moisture content in stages, prolong the hydration time, reduce the shrinkage rate, and at the same time ensure the fluidity of the material so that it can be fully mixed with the soft soil, thereby improving the curing effect of the soft soil. Detailed Implementation

[0039] To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0040] In this invention, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0041] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0042] It should be understood that in various embodiments of the present invention, the order of the above-mentioned processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0043] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0044] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the mass described in the embodiments of this invention can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0045] This invention provides a soft soil solidification and remediation material based on industrial solid waste, comprising, by weight, 30-40 parts vanadium slag-boron mud composite, 25-35 parts municipal sludge-dredging sludge composite, 15-20 parts waste ceramic powder, 5-8 parts modified steel slag powder, 4-6 parts metakaolin-silica composite, 3-5 parts alkali activator, 2-6 parts biomineralizing agent, 2-3 parts nanocomposite adsorbent, 1-2 parts amphoteric polymer flocculant, 1.5-2.5 parts crack-resistant-water-retaining composite agent, and 1.5-2 parts ecological restoration agent; the total of the above substances is referred to as dry material, and the mixing water accounts for 22%-28% of the total dry material mass.

[0046] In some embodiments, the preparation method of vanadium slag-boron mud composite material includes:

[0047] Vanadium slag and boron mud were mixed at a mass ratio of (2~4):1 to obtain a first mixture. A composite modifier was added to the first mixture and mixed thoroughly. The mixture was then placed in a rotary kiln and calcined at 850~950℃ for 2.5~3.5 hours at a heating rate of 5~8℃ / min. After cooling, the mixture was placed in a planetary ball mill for ball milling. Vanadium slag-boron mud composite material with a particle size of 0.08~0.2mm was screened for later use. The milling media were Φ10mm alumina balls. The material ratio is 5:1; the mass fraction of V2O5 in the vanadium slag-boron mud composite material is ≤0.5%, the mass fraction of CaO is 35%~42%, and the mass fraction of SiO2 is 25%~30%; among them, the vanadium slag is the tailings of vanadium smelting in a converter; the boron mud is the waste material from borax production; the composite modifier includes sodium carbonate and sodium fluoride, the mass ratio of sodium carbonate and sodium fluoride is (2~3):1, and the mass of the composite modifier is 6%~8% of the mass of the first mixture.

[0048] The vanadium slag-boron mud composite material prepared by the above method is used for soft soil solidification. The active components in the vanadium slag-boron mud composite material generate cementitious substances under the action of alkaline activators, which enhance the compressive strength and cohesion of the solidified soil and improve its bearing capacity. It can also inhibit the drying shrinkage deformation of the soft soil after solidification, reduce the risk of cracking, and improve the durability of the engineering structure.

[0049] In some embodiments, a method for preparing municipal sludge-dredging sludge composite material includes:

[0050] The municipal sludge has a moisture content of 50%~60%; the dredged sludge has a moisture content of 60%~70% and an organic matter mass fraction of 15%~20%. The municipal sludge and dredged sludge are placed in a plasma device at a mass ratio of (2~3):1 and subjected to plasma treatment for 8~12 minutes in an environment with a discharge power of 500~600W, a frequency of 10~15kHz, and a nitrogen flow rate of 2~3L / min to obtain a municipal sludge-dredged sludge composite material. This composite material is stored in a sealed container and used within 24 hours. The organic matter mass fraction in the municipal sludge-dredged sludge composite material is 20%~30%, the particle size is ≤0.5mm, and the pathogen kill rate is ≥99%.

[0051] Treated municipal sludge and dredged silt, when used as soft soil solidification materials, can not only effectively utilize waste materials, but also react with activators to generate cementitious products, enhancing the compressive strength and bearing capacity of the solidified soil; it can also inhibit the drying shrinkage deformation of the solidified soil, reduce cracking, and ensure the durability of the project.

[0052] In some embodiments, the method for preparing waste ceramic powder includes:

[0053] Construction waste ceramics are crushed to a particle size of ≤2mm using a jaw crusher, and then fed into a vibrating ball mill for ball milling at a speed of 300~350r / min. Waste ceramic powder with a particle size of 0.045~0.1mm is screened for later use. The ball milling media are φ5mm zirconia balls. The mass fraction of Al2O3 in the waste ceramic powder is 35%~45%, and the mass fraction of SiO2 is 50%~60%.

[0054] The main components of waste ceramic powder are Al2O3 and SiO2. Waste ceramic powder can fill the pores of soft soil, build a supporting skeleton, and improve the density. When combined with an activator, it reacts to generate CSH and CAH gels, which enhance the mechanical strength of the solidified soil. Its stable components and low shrinkage characteristics can reduce cracking of solidified soil, improve corrosion resistance and volume stability, and meet the needs of soft soil treatment.

[0055] In some embodiments, the method for preparing modified steel slag powder includes:

[0056] The converter slag is water-quenched at 50-60℃, followed by magnetic separation to remove iron using a magnetic field strength of 1200-1500 Gs. Subsequently, it is calcined at 1050-1150℃ for 1.5-2 hours to obtain slag powder. The cooled slag powder is then added to a mixer with a silane coupling agent and stirred at 1500-2000 r / min for 15-20 minutes to obtain modified slag powder. The silane coupling agent is KH-560 with a purity ≥98%, and its mass is 3%-5% of the slag powder mass. The modified slag powder has a specific surface area of ​​400-500 m². 2 / kg, f-CaO mass fraction ≤3%.

[0057] The improved steel slag powder prepared by the above method has a large specific surface area, which can expand the bonding with other substances; it can also activate the activity of silicon and aluminum components in steel slag powder, promote the generation of more cementitious products, and improve the compressive strength and bearing capacity of solidified soil; at the same time, it reduces interfacial porosity, enhances impermeability, inhibits drying shrinkage cracking, and ensures the long-term durability of the solidified body.

[0058] In some embodiments, the preparation method of metakaolin-silica composite material includes:

[0059] Metakaolin, silica fume, and nano-TiO2 were ultrasonically dispersed at 300W for 20 minutes to obtain a metakaolin-silica fume composite material. The mass ratio of metakaolin to silica fume was (3~4):1, and the mass of nano-TiO2 accounted for 2%~3% of the total mass of metakaolin and silica fume. The metakaolin was obtained by calcining kaolin in a muffle furnace at 800~900℃ for 2 hours and holding for 1 hour. The silica fume contained SiO2 with a mass fraction ≥90% and a specific surface area ≥20000 m². 2 / kg; the nano-TiO2 is anatase, with a particle size of 20~30nm and a purity of ≥99%.

[0060] The metakaolin-silica composite material prepared by the above method has highly active silica-alumina components in metakaolin and silica, which can efficiently generate cementitious products, significantly improving the compressive strength and impermeability of the solidified soil; nano-TiO2 can degrade soil pollutants, improve ecological compatibility, refine the cementitious structure, reduce drying shrinkage and cracking, and take into account both the stability of soft soil foundation and environmental friendliness.

[0061] In some embodiments, the method for preparing the alkali activator includes:

[0062] By mass percentage, 30%~40% lithium hydroxide, 40%~50% water glass, 10%~20% sodium pyrophosphate, and 5%~10% tartaric acid are stirred in a stirred tank at a speed of 600~800 r / min for 30 minutes to obtain an alkali activator; wherein, the purity of lithium hydroxide is ≥98%, the modulus of water glass is 3.0~3.2, and sodium pyrophosphate and tartaric acid are analytical grade.

[0063] The alkali activator prepared by the above method can efficiently activate the active components in soft soil and solidification materials, accelerate the generation of gel products, improve the solidification speed of solidified soil, and significantly enhance the compressive strength and cohesion of solidified soil. At the same time, it can optimize the density of the cementitious structure, reduce porosity, and enhance impermeability. It can also inhibit the drying shrinkage deformation of the solidified body, reduce the risk of cracking, and ensure the long-term bearing stability of soft soil foundation or roadbed.

[0064] In some embodiments, the method for preparing a biomineralizing bacterial agent includes:

[0065] Bacillus pasteurellii was cultured in LB medium (Luria-Bertani medium) at 20-30°C with shaking for 24 hours to obtain a bacterial suspension with a concentration of 10. 8 ~10 9 CFU / mL; the strain number of Bacillus pasteurellis was ATCC 11859; the yeast extract content in LB medium was 10 g / L, the peptone content was 20 g / L, the NaCl content was 5 g / L, and the pH was 7.0~7.2.

[0066] The bacterial solution and urease were mixed at a volume ratio of (4~6):1 to obtain a biomineralizing bacterial agent, which was then stored at 4℃. The urease was derived from sword bean and had an enzyme activity ≥2000U / g.

[0067] The biomineralizing agent prepared by the above method can metabolize into minerals such as calcium carbonate, which fill the pores of soft soil and cement soil particles, improving density and impermeability. The minerals can enhance the strength of the soil skeleton, improve compressive and shear properties, and increase the bearing capacity of the foundation, while avoiding chemical reagent pollution and taking into account both engineering stability and environmental compatibility.

[0068] In some embodiments, the preparation method of the nanocomposite adsorbent includes:

[0069] Montmorillonite, nano-hydroxyapatite, and graphene oxide were added to water at a mass ratio of (2~3):(1~2):1 and ultrasonically dispersed for 30 minutes at 300W to obtain a second mixture. The solid-liquid ratio of the second mixture was 1:(20~25). The second mixture was vacuum dried at 60~70℃ and a vacuum degree of -0.08MPa. After cooling, it was ground and screened to obtain nano-composite adsorbents with a particle size ≤5μm for later use.

[0070] Among them, montmorillonite has a particle size ≤2μm and a cation exchange capacity ≥100meq / 100g; nano-hydroxyapatite has a particle size of 50~100nm and a Ca / P ratio of 1.62~1.72; graphene oxide has a thickness ≤1nm and an oxygen content ≥30%.

[0071] The nanocomposite adsorbent prepared by the above method has strong ion exchange and water retention properties that optimize soil structure; nano-hydroxyapatite can fill pores and promote cementation; graphene oxide enhances interfacial bonding; the three work synergistically to improve the compactness, compressive strength and impermeability of the solidified soil, reduce drying shrinkage and cracking, and ensure long-term stability.

[0072] In some embodiments, the preparation method of the amphoteric polymeric flocculant includes:

[0073] Acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride were added to water at a molar ratio of (3~4):(1~2):1 to obtain a third mixture with a mass concentration of 20%~25%. An initiator was added to the third mixture, and polymerization was initiated at 50~60℃ for 4~6 hours to obtain an amphoteric polymer flocculant. The mass of the initiator added was 0.1%~0.2% of the total mass of acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride. The initiator included ammonium persulfate-sodium bisulfite.

[0074] The resulting amphoteric polymeric flocculant has a molecular weight of 12-15 million, a cationicity of 25%-35%, an anionicity of 10%-15%, and a dissolution time of ≤30 minutes.

[0075] The amphoteric polymer flocculant prepared by the above method can rapidly adsorb soft soil particles with its amphoteric groups, promote particle aggregation, reduce free water, and improve soil density; it can also enhance the cohesion between particles, help improve the compressive strength and shear performance of the solidified soil; at the same time, it optimizes the soil structure, reduces the resistance of subsequent cementation reaction, reduces drying shrinkage deformation, and ensures the stability and durability of soft soil foundations or roadbeds.

[0076] In some embodiments, the preparation method of the crack-resistant-water-retaining composite agent includes:

[0077] Hydroxypropyl methylcellulose and polyvinyl alcohol fiber are mixed at a mass ratio of (3~5):1 to obtain a crack-resistant and water-retaining composite agent; wherein the viscosity of hydroxypropyl methylcellulose is 100,000~150,000 mPa•s, and the methoxy content in hydroxypropyl methylcellulose is 28%~30%; the length of polyvinyl alcohol fiber is 6~12 mm, the diameter is 20~30 μm, and the tensile strength is ≥800 MPa.

[0078] The crack-resistant and water-retaining composite agent prepared by the above method contains hydroxypropyl methylcellulose, which can lock in moisture in soft soil, delay evaporation, and reduce shrinkage porosity; and polyvinyl alcohol fiber, which can disperse shrinkage stress and inhibit crack initiation and propagation. The two work synergistically to improve the compactness and crack resistance of the solidified soil, while also helping to enhance soil cohesion, ensuring the long-term structural stability and durability of soft soil foundations or roadbeds.

[0079] In some embodiments, the method for preparing the ecological restoration agent includes:

[0080] An ecological restoration agent was prepared by mixing humic acid, slow-release compound fertilizer, and arbuscular mycorrhizal fungal spores at a mass ratio of (3~5):(2~3):1; wherein the purity of humic acid was ≥90%; the mass fraction of N+P2O5+K2O in the slow-release compound fertilizer was ≥25%, and the slow-release period was ≥90 days; the arbuscular mycorrhizal fungal spores used were Glomus mosseae, with a concentration ≥10. 6 per g.

[0081] The ecological restoration agent prepared by the above method can regulate the soil microenvironment, reduce the risk of chemical residues, improve soil permeability and fertility, create conditions for subsequent vegetation restoration, and achieve synergy between engineering stability and ecological restoration.

[0082] In some embodiments, the mixing water is an aqueous solution of calcium nitrate with a mass fraction of 0.5% to 1%, using deionized water or municipal tap water, with a pH of 6.5 to 8.5; the calcium nitrate is of analytical grade; calcium nitrate, as a biomineralization reaction aid, can promote the formation of calcium carbonate crystals.

[0083] The present invention provides a method for preparing soft soil solidification and remediation materials based on industrial solid waste, comprising:

[0084] The main mixture is prepared by mixing vanadium slag-boron mud composite material, municipal sludge-dredging sludge composite material, waste ceramic powder and mixing water.

[0085] Modified steel slag powder, metakaolin-silica composite material, alkali activator and mixing water are added to the main mixture to obtain a solidified mixture;

[0086] After adding nanocomposite adsorbent, amphoteric polymer flocculant, crack-resistant and water-retaining composite agent, ecological restoration agent and mixing water to the solidified mixture and mixing evenly, biomineralizing bacteria are added to obtain soft soil solidification and repair material.

[0087] In some embodiments, vanadium slag-boron mud composite material, municipal sludge-dredging sludge composite material, waste ceramic powder and 40% mixing water are added to a mixer and stirred at a speed of 120~150 r / min for 6~8 minutes to obtain the main mixture. During the stirring process, the temperature is controlled to be below 40℃.

[0088] Add modified steel slag powder, metakaolin-silica composite material and alkali activator to the main mixture, stir at 250~300 r / min for 10~12 minutes, add 30% mixing water in three equal portions during the stirring process, and mix evenly to obtain solidified mixture;

[0089] Add nano-composite adsorbent, amphoteric polymer flocculant, crack-resistant and water-retaining composite agent, ecological restoration agent and 30% mixing water to the solidified mixture, stir at 350~400 r / min for 8~10 minutes, and finally add biomineralizing bacteria agent, stir at 100~120 r / min for 3~5 minutes to mix evenly. When the fluidity reaches 160~200 mm, the soft soil solidification and repair material is obtained.

[0090] This invention also provides applications of the soft soil consolidation and repair material prepared by the above method, as detailed below:

[0091] Mix the soft soil solidification and repair material with the soft soil evenly. The mass of the soft soil solidification and repair material added should be 8% to 10% of the bulk density of the soft soil. After the construction area is mixed, level it.

[0092] Primary curing: After the construction area is leveled, let it stand for 24 hours in an environment with a humidity of 90%~95%;

[0093] Intensive maintenance: After the initial maintenance, intensify maintenance for 3 days in an environment with a humidity of 85%~90%. Spray a 0.3% urea solution twice a day at 9:00 and 15:00, with the amount of urea solution used each time being 2%~3% of the mass of the soft soil solidification and repair material.

[0094] Ecological maintenance: After intensive maintenance, allow the soil to cure naturally in an environment with humidity above 80% for 24 days. Spray trace element nutrient solution once a week, with the amount of trace element nutrient solution used each time being 1% to 2% of the mass of the soft soil solidification and repair material. The trace element nutrient solution includes 0.05% FeSO4·7H2O, 0.03% MnSO4·H2O and 0.02% ZnSO4·7H2O by mass concentration.

[0095] This invention involves thoroughly mixing an eco-friendly soft soil solidification and remediation material based on multi-source industrial solid waste with soft soil, followed by initial curing to form a basic framework structure. This ensures stable matrix support for subsequent intensive curing stages, preventing performance limitations due to structural defects in later processes. Intensive curing stimulates the synergistic effect of multiphase materials, ensuring mechanical properties and pollution control effectiveness. Ecological curing simulates the natural soil microenvironment, creating conditions for the colonization and reproduction of soil microorganisms, allowing the biocompatible components in the soft soil solidification and remediation material to function effectively, resulting in a more durable and ecologically sound solidification and remediation effect. Through targeted regulation at each stage, the mechanical strength, heavy metal stability, and ecological compatibility of the solidified substrate are synergistically improved, ultimately ensuring that the solidified substrate meets engineering safety requirements and ecological remediation needs.

[0096] In the following embodiments, unless otherwise specified, all materials used can be obtained through ordinary channels; the testing methods used are conventional methods in the art.

[0097] Example 1

[0098] Substrate preparation:

[0099] Vanadium slag and boron mud were mixed at a mass ratio of 3:1 to obtain the first mixture. 6% of the composite modifier was added to the first mixture and mixed evenly. The mixture was then placed in a rotary kiln and calcined at 890℃ for 3 hours at a heating rate of 8℃ / min. After cooling, the mixture was ball-milled and screened to obtain vanadium slag-boron mud composite material with a particle size of 0.08~0.2mm for later use. The composite modifier included sodium carbonate and sodium fluoride, with a mass ratio of sodium carbonate to sodium fluoride of 2:1.

[0100] Municipal sludge with a moisture content of 50% and dredged sludge with a moisture content of 60% and an organic matter content of 20% were mixed at a mass ratio of 2:1. The mixture was then subjected to plasma treatment for 10 minutes in an environment with a discharge power of 550W, a frequency of 12kHz, and a nitrogen flow rate of 2L / min to obtain a municipal sludge-dredged sludge composite material. The organic matter content of the municipal sludge-dredged sludge composite material was 30%, the particle size was ≤0.5mm, and the pathogen kill rate was 99%.

[0101] Construction waste ceramics are crushed to a particle size of ≤2mm by a jaw crusher, and then put into a vibrating ball mill for ball milling at a speed of 300r / min. Waste ceramic powder with a particle size of 0.045~0.1mm is screened for later use. The mass fraction of Al2O3 in the waste ceramic powder is 35%, and the mass fraction of SiO2 is 58%.

[0102] The converter slag was subjected to water quenching at 560℃, followed by magnetic separation to remove iron using a magnetic field strength of 1200 Gs. Subsequently, it was calcined at 1050℃ for 1.5 hours to obtain slag powder. The cooled slag powder was then mixed with KH-560 silane coupling agent in a mixer at 1500 r / min for 15 minutes to obtain modified slag powder. The mass of the silane coupling agent was 3% of the slag powder mass, and the mass fraction of f-CaO in the modified slag powder was 3%.

[0103] Metakaolin, silica fume, and nano-TiO2 were ultrasonically dispersed at 300W for 20 minutes to obtain a metakaolin-silica fume composite material. The mass ratio of metakaolin to silica fume was 3:1, and the mass of nano-TiO2 accounted for 2% of the total mass of metakaolin and silica fume. Metakaolin was obtained by calcining kaolin at 800℃ for 2 hours and holding it at that temperature for 1 hour in a muffle furnace. The mass fraction of SiO2 in silica fume was 90%. The nano-TiO2 was anatase with a particle size of 20~30nm.

[0104] An alkali activator was obtained by mixing 30% lithium hydroxide, 45% water glass, 20% sodium pyrophosphate, and 5% tartaric acid in a stirred tank at a speed of 600 r / min for 30 minutes, by mass percentage; wherein the modulus of water glass is 3.0.

[0105] Bacillus pasteurellii was cultured in LB medium at 30°C with shaking for 24 hours to obtain a bacterial suspension with a concentration of 10. 8 CFU / mL; mix the bacterial solution with urease at a volume ratio of 5:1 to obtain a biomineralizing bacterial agent, and store at 4°C.

[0106] Montmorillonite, nano-hydroxyapatite, and graphene oxide were added to water at a mass ratio of 5:3:2 and ultrasonically dispersed at 300W for 30 minutes to obtain a second mixture. The solid-liquid ratio of the second mixture was 1:20. The second mixture was vacuum dried at 60℃ and a vacuum degree of -0.08MPa. After cooling, it was ground and screened to obtain nano-composite adsorbents with a particle size ≤5μm for later use.

[0107] Acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride were added to water at a molar ratio of 3:1:1 to obtain a third mixture with a mass concentration of 23%. Ammonium persulfate-sodium bisulfite was added to the third mixture, and polymerization was initiated at 50°C for 4 hours to obtain an amphoteric polymeric flocculant. The mass of ammonium persulfate-sodium bisulfite added was 0.15% of the total mass of acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride. The resulting amphoteric polymeric flocculant had a molecular weight of 1200, a cationicity of 25%, an anionicity of 10%, and a dissolution time of 28 minutes.

[0108] Hydroxypropyl methylcellulose and polyvinyl alcohol fiber are mixed at a mass ratio of 5:1 to obtain a crack-resistant and water-retaining composite agent; wherein the viscosity of hydroxypropyl methylcellulose is 100000 mPa•s and the methoxy content in hydroxypropyl methylcellulose is 28%; the length of polyvinyl alcohol fiber is 6 mm, the diameter is 20 μm, and the tensile strength is ≥800 MPa.

[0109] An ecological restoration agent was prepared by mixing humic acid, slow-release compound fertilizer, and arbuscular mycorrhizal fungal spores at a mass ratio of 3:2:1; wherein the purity of humic acid was 90%; the mass fraction of N+P2O5+K2O in the slow-release compound fertilizer was 25%; and the concentration of arbuscular mycorrhizal fungal spores was 10%. 6 per g.

[0110] The mixing water is an aqueous solution of calcium nitrate with a mass fraction of 0.7%.

[0111] The substrate prepared above is used to prepare soft soil consolidation and remediation materials, including:

[0112] Add 35.2 parts of vanadium slag-boron mud composite material, 30.5 parts of municipal sludge-dredging sludge composite material, 20 parts of waste ceramic powder and 40% of mixing water to a mixer and stir at 135 r / min for 7 minutes to obtain the main mixture.

[0113] Add 6.3 parts of modified steel slag powder, 5.5 parts of metakaolin-silica composite material, and 5 parts of alkali activator to the main mixture. Stir at 250 r / min for 10 minutes. During the stirring process, add 30% of the mixing water in three equal portions and mix evenly to obtain the solidified mixture.

[0114] Add 2.6 parts of nanocomposite adsorbent, 1.5 parts of amphoteric polymer flocculant, 2.1 parts of crack-resistant and water-retaining composite agent, 2.0 parts of ecological restoration agent and 40% of mixing water to the solidified mixture. Stir at 380 r / min for 9 minutes to mix evenly. Then add 4 parts of biomineralizing agent and stir at 110 r / min for 4 minutes to obtain soft soil solidification and repair material. The fluidity of the soft soil solidification and repair material is 172 mm.

[0115] The total amount of mixing water accounted for 25.3% of the total dry material mass.

[0116] The soft soil solidification and repair material prepared in this embodiment is mixed evenly with soft soil. The mass of the soft soil solidification and repair material is 10% of the bulk density of the soft soil. After the construction area is mixed, it is leveled.

[0117] Primary maintenance: After the construction area is leveled, let it stand for 24 hours in an environment with a humidity of 90%~95%.

[0118] Intensive maintenance: After the initial maintenance, intensify maintenance for 3 days in an environment with a humidity of 85%~90%. Spray a 0.3% urea solution once each at 9:00 and 15:00 every day. The amount of urea solution used each time is 2% of the mass of the soft soil solidification and repair material.

[0119] Ecological maintenance: After intensive maintenance, allow the soil to rest in a natural environment with a humidity of 80%~90% for 24 days. Spray trace element nutrient solution once a week, with the amount of trace element nutrient solution used each time being 2% of the mass of the soft soil solidification and repair material. The trace element nutrient solution, by mass concentration, includes 0.05% FeSO4·7H2O, 0.03% MnSO4·H2O and 0.02% ZnSO4·7H2O.

[0120] The cured substrate was tested for relevant properties, and the results are as follows: the unconfined compressive strength at 7 days was 3.26 MPa, reaching 5.78 MPa at 28 days, with a strength increase rate of 77.3%, indicating balanced development after softening. It exhibits high stability against heavy metals, with low Pb content in the soft soil. 2+ The initial concentration was 125 mg / kg, Cd 2+ The initial concentration was 8.6 mg / kg. After treatment, the soft soil showed a Pb concentration of... 2+ Cd 2+The leaching concentrations decreased to 0.12 mg / L and 0.032 mg / L, respectively, far below the Class III limit of the "Groundwater Quality Standard" (GB / T14848-2017). After curing, the substrate had a pH of 7.8, an organic matter mass fraction of 24.3%, and an E. coli kill rate of 99.6%.

[0121] Example 2

[0122] Substrate preparation:

[0123] Vanadium slag and boron mud were mixed at a mass ratio of 2:1 to obtain a first mixture. 8% of a composite modifier was added to the first mixture and mixed evenly. The mixture was then placed in a rotary kiln and calcined at 850℃ for 3 hours at a heating rate of 8℃ / min. After cooling, the mixture was ball-milled, and vanadium slag-boron mud composite material with a particle size of 0.08~0.2mm was screened for later use. The composite modifier included sodium carbonate and sodium fluoride, with a mass ratio of sodium carbonate to sodium fluoride of 2.5:1.

[0124] Municipal sludge with a moisture content of 55% and dredged sludge with a moisture content of 65% and an organic matter content of 18% were mixed at a mass ratio of 2.5:1. The mixture was then subjected to plasma treatment for 10 minutes in an environment with a discharge power of 580W, a frequency of 15kHz, and a nitrogen flow rate of 2L / min to obtain a municipal sludge-dredged sludge composite material. The organic matter content of the municipal sludge-dredged sludge composite material was 28.7%, the particle size was ≤0.5mm, and the pathogen kill rate was 99%.

[0125] Construction waste ceramics are crushed to a particle size of ≤2mm by a jaw crusher, and then put into a vibrating ball mill for ball milling at a speed of 300r / min. Waste ceramic powder with a particle size of 0.045~0.1mm is screened for later use. The mass fraction of Al2O3 in the waste ceramic powder is 41.6%, and the mass fraction of SiO2 is 51.5%.

[0126] The converter slag was water-quenched at 560℃, followed by magnetic separation to remove iron using a magnetic field strength of 1200 Gs. Subsequently, it was calcined at 1110℃ for 1.5 hours to obtain slag powder. The cooled slag powder was then mixed with KH-560 silane coupling agent in a mixer at 1500 r / min for 15 minutes to obtain modified slag powder. The mass of the silane coupling agent was 5% of the slag powder mass. The mass fraction of f-CaO in the modified slag powder was 2.8%.

[0127] Metakaolin, silica fume, and nano-TiO2 were ultrasonically dispersed at 300W for 20 minutes to obtain a metakaolin-silica fume composite material. The mass ratio of metakaolin to silica fume was 3.5:1, and the mass of nano-TiO2 accounted for 3% of the total mass of metakaolin and silica fume. Metakaolin was obtained by calcining kaolin at 850℃ for 2 hours and holding it at that temperature for 1 hour in a muffle furnace. The mass fraction of SiO2 in silica fume was 90%. The nano-TiO2 was anatase with a particle size of 20~30nm.

[0128] An alkali activator was obtained by stirring 35% lithium hydroxide, 45% water glass, 10% sodium pyrophosphate, and 10% tartaric acid in a stirred tank at a speed of 600 r / min for 30 minutes, by mass percentage; wherein the modulus of water glass is 3.0.

[0129] Bacillus pasteurellii was cultured in LB medium at 25°C with shaking for 24 hours to obtain a bacterial suspension with a concentration of 10. 9 CFU / mL; mix the bacterial solution with urease at a volume ratio of 4:1 to obtain a biomineralizing bacterial agent, and store at 4°C.

[0130] Montmorillonite, nano-hydroxyapatite, and graphene oxide were added to water at a mass ratio of 2:1:1 and dispersed by ultrasonication at 300W for 30 minutes to obtain a second mixture. The solid-liquid ratio of the second mixture was 1:20. The second mixture was vacuum dried at 68℃ and a vacuum degree of -0.08MPa. After cooling, it was ground and screened to obtain nano-composite adsorbents with a particle size ≤5μm for later use.

[0131] Acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride were added to water at a molar ratio of 4:1.5:1 to obtain a third mixture with a mass concentration of 25%. Ammonium persulfate-sodium bisulfite was added to the third mixture, and polymerization was initiated at 60°C for 4 hours to obtain an amphoteric polymeric flocculant. The mass of ammonium persulfate-sodium bisulfite added was 0.2% of the total mass of acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride. The resulting amphoteric polymeric flocculant had a molecular weight of 1500, a cationicity of 35%, an anionicity of 15%, and a dissolution time of 30 minutes.

[0132] Hydroxypropyl methylcellulose and polyvinyl alcohol fiber were mixed at a mass ratio of 4:1 to obtain an anti-crack and water-retaining composite agent; wherein the viscosity of hydroxypropyl methylcellulose was 100,000 mPa•s and the methoxy content in hydroxypropyl methylcellulose was 28%; the length of polyvinyl alcohol fiber was 6 mm, the diameter was 20 μm, and the tensile strength was ≥800 MPa.

[0133] An ecological restoration agent was prepared by mixing humic acid, slow-release compound fertilizer, and arbuscular mycorrhizal fungal spores at a mass ratio of 5:3:1; wherein the purity of humic acid was 90%; the mass fraction of N+P2O5+K2O in the slow-release compound fertilizer was 25%; and the concentration of arbuscular mycorrhizal fungal spores was 10%. 6 per g.

[0134] The mixing water is an aqueous solution of calcium nitrate with a mass fraction of 0.8%.

[0135] The substrate prepared above is used to prepare soft soil consolidation and remediation materials, including:

[0136] Add 32.7 parts of vanadium slag-boron mud composite material, 25 parts of municipal sludge-dredging sludge composite material, 17 parts of waste ceramic powder and 40% of mixing water to a mixer and stir at 135 r / min for 7 minutes to obtain the main mixture.

[0137] Add 5.8 parts of modified steel slag powder, 6 parts of metakaolin-silica composite material, and 3.8 parts of alkali activator to the main mixture. Stir at 300 r / min for 12 minutes. During the stirring process, add 30% of the mixing water in three equal portions and mix evenly to obtain the solidified mixture.

[0138] Add 2.3 parts of nano-composite adsorbent, 2 parts of amphoteric polymer flocculant, 2.5 parts of crack-resistant and water-retaining composite agent, 1.5 parts of ecological restoration agent and 40% of mixing water to the solidified mixture. Stir at 360 r / min for 9 minutes to mix evenly. Then add 6 parts of biomineralizing agent and stir at 110 r / min for 4 minutes to obtain soft soil solidification and repair material. The fluidity of the soft soil solidification and repair material is 200 mm.

[0139] The total amount of mixing water accounts for 28% of the total dry material mass.

[0140] The soft soil solidification and repair material prepared in this embodiment is mixed evenly with soft soil. The mass of the soft soil solidification and repair material is 10% of the bulk density of the soft soil. After the construction area is mixed, it is leveled.

[0141] Primary maintenance: After the construction area is leveled, let it stand for 24 hours in an environment with a humidity of 90%~95%.

[0142] Intensive maintenance: After the initial maintenance, intensify maintenance for 3 days in an environment with a humidity of 85%~90%. Spray a 0.3% urea solution once each at 9:00 and 15:00 every day. The amount of urea solution used each time is 3% of the mass of the soft soil solidification and repair material.

[0143] Ecological maintenance: After intensive maintenance, allow the soil to cure naturally in an environment with a humidity of 80-90% for 24 days. Spray trace element nutrient solution once a week, with the amount of trace element nutrient solution used each time being 1.8% of the mass of the soft soil solidification and repair material. The trace element nutrient solution, by mass concentration, includes 0.05% FeSO4·7H2O, 0.03% MnSO4·H2O, and 0.02% ZnSO4·7H2O.

[0144] The properties of the cured substrate were tested, and the results are as follows: 30 days after planting ryegrass, the germination rate was 89.6%, the plant height was 12.4 cm, and the root length was 9.8 cm. The arbuscular mycorrhizal fungal infection rate was 68.5%, and the soil urease activity was 18.6 mg / (g•d), which was 2.3 times higher than before treatment. The permeability coefficient of the cured substrate was 1.2 × 10⁻⁶. -7 The surface crack density is 0.08 cracks / m² after 28 days, exhibiting good crack resistance (cm / s). 2 .

[0145] Example 3

[0146] Substrate preparation:

[0147] Vanadium slag and boron mud were mixed at a mass ratio of 4:1 to obtain the first mixture. 7% of the composite modifier was added to the first mixture and mixed evenly. The mixture was then placed in a rotary kiln and calcined at 950℃ for 3 hours at a heating rate of 8℃ / min. After cooling, the mixture was ball-milled and screened to obtain vanadium slag-boron mud composite material with a particle size of 0.08~0.2mm for later use. The composite modifier included sodium carbonate and sodium fluoride, with a mass ratio of sodium carbonate to sodium fluoride of 3:1.

[0148] Municipal sludge with a moisture content of 60% and dredged sludge with a moisture content of 70% and an organic matter content of 15% were mixed at a mass ratio of 2:1 and then subjected to plasma treatment for 10 minutes in an environment with a discharge power of 550W, a frequency of 10kHz, and a nitrogen flow rate of 2L / min to obtain a municipal sludge-dredged sludge composite material. The municipal sludge-dredged sludge composite material has an organic matter content of 20%, a particle size of ≤0.5mm, and a pathogen kill rate of 99%.

[0149] Construction waste ceramics are crushed to a particle size of ≤2mm by a jaw crusher, and then put into a vibrating ball mill for ball milling at a speed of 350r / min. The waste ceramic powder with a particle size of 0.045~0.1mm is screened for later use. The mass fraction of Al2O3 in the waste ceramic powder is 45%, and the mass fraction of SiO2 is 50%.

[0150] The converter steel slag was subjected to water quenching at a temperature of 560℃, followed by magnetic separation to remove iron using a magnetic field strength of 1200Gs. Subsequently, it was calcined at 1110℃ for 1.5 hours to obtain steel slag powder. The cooled steel slag powder was then modified by stirring with KH-560 silane coupling agent in a mixer at a speed of 1500r / min for 15 minutes to obtain modified steel slag powder. The mass of the silane coupling agent was 3% of the mass of the steel slag powder, and the mass fraction of f-CaO in the modified steel slag powder was 2.5%.

[0151] Metakaolin, silica fume, and nano-TiO2 were ultrasonically dispersed at 300W for 20 minutes to obtain a metakaolin-silica fume composite material. The mass ratio of metakaolin to silica fume was 4:1, and the mass of nano-TiO2 accounted for 2.5% of the total mass of metakaolin and silica fume. Metakaolin was obtained by calcining kaolin in a muffle furnace at 850℃ for 2 hours and holding for 1 hour. The mass fraction of SiO2 in silica fume was 90%. The nano-TiO2 was anatase with a particle size of 20~30nm.

[0152] An alkali activator was obtained by stirring 40% lithium hydroxide, 40% water glass, 15% sodium pyrophosphate, and 5% tartaric acid in a stirred tank at a speed of 600 r / min for 30 minutes by mass percentage; wherein the modulus of water glass is 3.0.

[0153] Bacillus pasteurellii was cultured in LB medium at 20°C with shaking for 24 hours to obtain a bacterial suspension with a concentration of 8 × 10⁻⁶. 8 CFU / mL; mix the bacterial solution with urease at a volume ratio of 5:1 to obtain a biomineralizing bacterial agent, and store at 4°C.

[0154] Montmorillonite, nano-hydroxyapatite, and graphene oxide were added to water at a mass ratio of 3:2:1 and ultrasonically dispersed at 300W for 30 minutes to obtain a second mixture. The solid-liquid ratio of the second mixture was 1:20. The second mixture was vacuum dried at 70℃ and a vacuum degree of -0.08MPa. After cooling, it was ground and screened to obtain nano-composite adsorbents with a particle size ≤5μm for later use.

[0155] Acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride were added to water at a molar ratio of 2:2:1 to obtain a third mixture with a mass concentration of 20%. Ammonium persulfate-sodium bisulfite was added to the third mixture, and polymerization was initiated at 55°C for 4 hours to obtain an amphoteric polymeric flocculant. The mass of ammonium persulfate-sodium bisulfite added was 0.1% of the total mass of acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride. The resulting amphoteric polymeric flocculant had a molecular weight of 1300, a cationicity of 30%, an anionicity of 12%, and a dissolution time of 30 minutes.

[0156] Hydroxypropyl methylcellulose and polyvinyl alcohol fiber were mixed at a mass ratio of 3:1 to obtain an anti-crack and water-retaining composite agent; wherein the viscosity of hydroxypropyl methylcellulose was 100,000 mPa•s and the methoxy content in hydroxypropyl methylcellulose was 28%; the length of polyvinyl alcohol fiber was 6 mm, the diameter was 20 μm, and the tensile strength was ≥800 MPa.

[0157] An ecological restoration agent was prepared by mixing humic acid, slow-release compound fertilizer, and arbuscular mycorrhizal fungal spores at a mass ratio of 4:2:1; wherein the purity of humic acid was 90%; the mass fraction of N+P2O5+K2O in the slow-release compound fertilizer was 25%; and the concentration of arbuscular mycorrhizal fungal spores was 10%. 6 per g.

[0158] The mixing water is an aqueous solution of calcium nitrate with a mass fraction of 0.6%.

[0159] The substrate prepared above is used to prepare soft soil consolidation and remediation materials, including:

[0160] Add 40 parts of vanadium slag-boron mud composite material, 32.1 parts of municipal sludge-dredging sludge composite material, 15 parts of waste ceramic powder and 40% of mixing water to a mixer and stir at 135 r / min for 7 minutes to obtain the main mixture.

[0161] Add 8 parts of modified steel slag powder, 4 parts of metakaolin-silica composite material, and 3 parts of alkali activator to the main mixture. Stir at 250 r / min for 12 minutes. During the stirring process, add 30% of the mixing water in three equal portions and mix evenly to obtain the solidified mixture.

[0162] Add 3.0 parts of nano-composite adsorbent, 1 part of amphoteric polymer flocculant, 1.5 parts of crack-resistant and water-retaining composite agent, 1.8 parts of ecological restoration agent and 40% of mixing water to the solidified mixture. Stir at 380 r / min for 9 minutes to mix evenly. Then add 2 parts of biomineralizing agent and stir at 110 r / min for 4 minutes to obtain soft soil solidification and repair material. The fluidity of the soft soil solidification and repair material is 160 mm.

[0163] The total amount of mixing water accounts for 22% of the total dry material mass.

[0164] The soft soil solidification and repair material prepared in this embodiment is mixed evenly with soft soil. The mass of the soft soil solidification and repair material is 9% of the bulk density of the soft soil. After the construction area is mixed, it is leveled.

[0165] Primary curing: After the construction area is leveled, let it stand for 24 hours in an environment with a humidity of 90%~95%;

[0166] Intensive maintenance: After the initial maintenance, intensify maintenance for 3 days in an environment with a humidity of 85%~90%. Spray a 0.3% urea solution once each at 9:00 and 15:00 every day. The amount of urea solution used each time is 3% of the mass of the soft soil solidification and repair material.

[0167] Ecological maintenance: After intensive maintenance, allow the soil to rest in a natural environment with a humidity of 80%~90% for 24 days. Spray trace element nutrient solution once a week, with the amount of trace element nutrient solution used each time being 2% of the mass of the soft soil solidification and repair material. The trace element nutrient solution, by mass concentration, includes 0.05% FeSO4·7H2O, 0.03% MnSO4·H2O and 0.02% ZnSO4·7H2O.

[0168] The soft soil stabilization and repair material in this embodiment is used to treat Cr. 6+ Concentration of 156 mg / kg, Cu 2+ Concentration of 98 mg / kg, Zn 2+ The contaminated soft soil had a concentration of 215 mg / kg. The solidified substrate was tested for relevant properties, and the results are as follows: Cr 6+ The leaching concentration was 0.08 mg / L, while the standard limit was 0.1 mg / L; Cu 2+ The leaching concentration was 0.32 mg / L, while the standard limit was 1.0 mg / L; Zn 2+ The leaching concentration was 0.58 mg / L, while the standard limit was 1.0 mg / L; the stability rate was >95%. The material did not exhibit significant delamination, and the compressive strength after 28 days was 4.92 MPa.

[0169] Example 4

[0170] Substrate preparation:

[0171] Vanadium slag and boron mud were mixed at a mass ratio of 3:1 to obtain the first mixture. 7% of the composite modifier was added to the first mixture and mixed evenly. The mixture was then placed in a rotary kiln and calcined at 900℃ for 3 hours at a heating rate of 8℃ / min. After cooling, the mixture was ball-milled and screened to obtain vanadium slag-boron mud composite material with a particle size of 0.08~0.2mm for later use. The composite modifier included sodium carbonate and sodium fluoride, with a mass ratio of sodium carbonate to sodium fluoride of 2.5:1.

[0172] Municipal sludge with a moisture content of 60% and dredged sludge with a moisture content of 65% and an organic matter content of 16.8% were mixed at a mass ratio of 3:1 and then subjected to plasma treatment for 10 minutes in an environment with a discharge power of 600W, a frequency of 12kHz, and a nitrogen flow rate of 2L / min to obtain a municipal sludge-dredged sludge composite material. The organic matter content of the municipal sludge-dredged sludge composite material was 21.3%, the particle size was ≤0.5mm, and the pathogen kill rate was 99%.

[0173] Construction waste ceramics are crushed to a particle size of ≤2mm by a jaw crusher, and then put into a vibrating ball mill for ball milling at a speed of 350r / min. The waste ceramic powder with a particle size of 0.045~0.1mm is screened for later use. The mass fraction of Al2O3 in the waste ceramic powder is 36.2%, and the mass fraction of SiO2 is 60%.

[0174] The converter steel slag was subjected to water quenching at a temperature of 560℃, followed by magnetic separation to remove iron using a magnetic field strength of 1200Gs. Subsequently, it was calcined at 1150℃ for 1.5 hours to obtain steel slag powder. The cooled steel slag powder was then modified by stirring with KH-560 silane coupling agent in a mixer at a speed of 1500r / min for 15 minutes to obtain modified steel slag powder. The mass of the silane coupling agent was 4% of the mass of the steel slag powder. The mass fraction of f-CaO in the modified steel slag powder was 2.2%.

[0175] Metakaolin, silica fume, and nano-TiO2 were ultrasonically dispersed at 300W for 20 minutes to obtain a metakaolin-silica fume composite material. The mass ratio of metakaolin to silica fume was 3.5:1, and the mass of nano-TiO2 accounted for 3% of the total mass of metakaolin and silica fume. Metakaolin was obtained by calcining kaolin at 900℃ for 2 hours and holding it at that temperature for 1 hour in a muffle furnace. The mass fraction of SiO2 in silica fume was 90%. The nano-TiO2 was anatase with a particle size of 20~30nm.

[0176] An alkali activator was obtained by stirring 30% lithium hydroxide, 50% water glass, 12% sodium pyrophosphate, and 8% tartaric acid in a stirred tank at a speed of 600 r / min for 30 minutes, by mass percentage; wherein the modulus of water glass is 3.0.

[0177] Bacillus pasteurellii was cultured in LB medium at 28°C with shaking for 24 hours to obtain a bacterial suspension with a concentration of 10. 8 CFU / mL; mix the bacterial solution with urease at a volume ratio of 6:1 to obtain a biomineralizing bacterial agent, and store at 4℃.

[0178] Montmorillonite, nano-hydroxyapatite, and graphene oxide were added to water at a mass ratio of 2:2:1 and ultrasonically dispersed at 300W for 30 minutes to obtain a second mixture. The solid-liquid ratio of the second mixture was 1:20. The second mixture was vacuum dried at 65℃ and a vacuum degree of -0.08MPa. After cooling, it was ground and screened to obtain nano-composite adsorbents with a particle size ≤5μm for later use.

[0179] Acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride were added to water at a molar ratio of 2.5:2:1 to obtain a third mixture with a mass concentration of 25%. Ammonium persulfate-sodium bisulfite was added to the third mixture, and polymerization was initiated at 55°C for 4 hours to obtain an amphoteric polymeric flocculant. The mass of ammonium persulfate-sodium bisulfite added was 0.2% of the total mass of acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride. The resulting amphoteric polymeric flocculant had a molecular weight of 1400, a cationicity of 32%, an anionicity of 10%, and a dissolution time of 28 minutes.

[0180] Hydroxypropyl methylcellulose and polyvinyl alcohol fiber were mixed at a mass ratio of 3:1 to obtain an anti-crack and water-retaining composite agent; wherein the viscosity of hydroxypropyl methylcellulose was 100,000 mPa•s and the methoxy content in hydroxypropyl methylcellulose was 28%; the length of polyvinyl alcohol fiber was 6 mm, the diameter was 20 μm, and the tensile strength was ≥800 MPa.

[0181] An ecological restoration agent was prepared by mixing humic acid, slow-release compound fertilizer, and arbuscular mycorrhizal fungal spores at a mass ratio of 3:2.5:1; wherein the purity of humic acid was 90%; the mass fraction of N+P2O5+K2O in the slow-release compound fertilizer was 25%; and the concentration of arbuscular mycorrhizal fungal spores was 10. 6 pcs / g;

[0182] The mixing water is an aqueous solution of calcium nitrate with a mass fraction of 0.7%.

[0183] The substrate prepared above is used to prepare soft soil consolidation and remediation materials, including:

[0184] Add 30 parts of vanadium slag-boron mud composite material, 35 parts of municipal sludge-dredging sludge composite material, 18.5 parts of waste ceramic powder and 40% of mixing water to a mixer and stir at 135 r / min for 7 minutes to obtain the main mixture.

[0185] Add 5 parts modified steel slag powder, 5 parts metakaolin-silica composite material, and 4.2 parts alkali activator to the main mixture. Stir at 300 r / min for 10 minutes. During the stirring process, add 30% mixing water in three equal portions and mix evenly to obtain a solidified mixture.

[0186] Two parts of nanocomposite adsorbent, 1.5 parts of amphoteric polymer flocculant, 1.8 parts of crack-resistant and water-retaining composite agent, 2.0 parts of ecological restoration agent, and 40% of mixing water were added to the solidified mixture. After mixing evenly at 380 r / min for 9 minutes, 5.2 parts of biomineralizing agent were added, and the mixture was stirred at 110 r / min for 4 minutes to obtain the soft soil solidification and repair material. The fluidity of the soft soil solidification and repair material was 186 mm.

[0187] The total amount of mixing water accounted for 26.8% of the total dry material mass.

[0188] The soft soil solidification and repair material prepared in this embodiment is mixed evenly with soft soil. The mass of the soft soil solidification and repair material is 8% of the bulk density of the soft soil. After the construction area is mixed, it is leveled.

[0189] Primary maintenance: After the construction area is leveled, let it stand for 24 hours in an environment with a humidity of 90%~95%.

[0190] Intensive maintenance: After the initial maintenance, intensify maintenance for 3 days in an environment with a humidity of 85%~90%. Spray a 0.3% urea solution once each at 9:00 and 15:00 every day. The amount of urea solution used each time is 3% of the mass of the soft soil solidification and repair material.

[0191] Ecological maintenance: After intensive maintenance, allow the soil to rest in a natural environment with a humidity of 80%~90% for 24 days. Spray trace element nutrient solution once a week, with the amount of trace element nutrient solution used each time being 2% of the mass of the soft soil solidification and repair material. The trace element nutrient solution, by mass concentration, includes 0.05% FeSO4·7H2O, 0.03% MnSO4·H2O and 0.02% ZnSO4·7H2O.

[0192] The cured substrate underwent relevant performance tests, and the results are as follows: The compressive strength reached 8.2 MPa, meeting the foundation strength requirements for most soft soil solidification projects, and the mechanical properties remained stable. The flexural strength was 1.5 MPa, demonstrating significantly enhanced crack resistance. The permeability coefficient was 4.2 × 10⁻⁶. -8 cm / s, possessing excellent seepage prevention capabilities. Pb 2+ The solidification rate is 92.8%, meeting the standards for safe use in soil environments. The drying shrinkage rate is 0.42%, which is superior to traditional cement-soil solidification materials, reducing subsequent maintenance costs.

[0193] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0194] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the claims of the present invention pending approval.

Claims

1. A soft soil consolidation and remediation material based on industrial solid waste, characterized in that, By weight, the mixture comprises 30-40 parts vanadium slag-boron mud composite material, 25-35 parts municipal sludge-dredging sludge composite material, 15-20 parts waste ceramic powder, 5-8 parts modified steel slag powder, 4-6 parts metakaolin-silica fume composite material, 3-5 parts alkali activator, 2-6 parts biomineralizing agent, 2-3 parts nanocomposite adsorbent, 1-2 parts amphoteric polymer flocculant, 1.5-2.5 parts crack-resistant-water-retaining composite agent, and 1.5-2 parts ecological restoration agent; the mixing water accounts for 22%-28% of the total mass of the above substances. The preparation method of the vanadium slag-boron mud composite material includes: Vanadium slag and boron mud were mixed at a mass ratio of (2~4):1 to obtain a first mixture. Sodium carbonate and sodium fluoride were added to the first mixture, and the mixture was calcined at 850~950℃ to obtain a vanadium slag-boron mud composite material. The total mass of sodium carbonate and sodium fluoride was 6%~8% of the mass of the first mixture, and the mass ratio of sodium carbonate to sodium fluoride was (2~3):

1. The preparation method of the municipal sludge-dredging sludge composite material includes: The municipal sludge and dredged sludge were mixed at a mass ratio of (2~3):1 and then subjected to plasma treatment to obtain a municipal sludge-dredged sludge composite material. The method for preparing the modified steel slag powder includes: After being quenched in water and magnetically separated to remove iron, the converter steel slag is calcined at 1050~1150℃ to obtain steel slag powder. The steel slag powder is then modified with a silane coupling agent to obtain modified steel slag powder. The preparation method of the metakaolin-silica composite material includes: Metakaolin is obtained by calcining kaolin at 800~900℃; Metakaolin, silica fume, and nano-TiO2 were mixed to obtain a metakaolin-silica fume composite material; the mass ratio of metakaolin to silica fume was (3~4):1, and the mass of nano-TiO2 accounted for 2%~3% of the total mass of metakaolin and silica fume; The preparation method of the nanocomposite adsorbent includes: Montmorillonite, nano-hydroxyapatite, and graphene oxide were added to water at a mass ratio of (2~3):(1~2):1 to obtain a second mixture. The second mixture was then vacuum dried at 60~70℃ and ground to obtain a nano-composite adsorbent.

2. The soft soil consolidation and remediation material based on industrial solid waste according to claim 1, characterized in that, The municipal sludge has a moisture content of 50% to 60%; the dredged sludge has an organic matter content of 15% to 20% and a moisture content of 60% to 70%; the municipal sludge-dredged sludge composite has an organic matter content of 20% to 30%. The waste ceramic powder contains 35% to 45% Al2O3 and 50% to 60% SiO2 by mass.

3. The soft soil consolidation and remediation material based on industrial solid waste according to claim 1, characterized in that, The method for preparing the alkaline activator includes: An alkaline activator is obtained by mixing 30%–40% lithium hydroxide, 40%–50% water glass, 10%–20% sodium pyrophosphate and 5%–10% tartaric acid by weight percentage.

4. The soft soil consolidation and remediation material based on industrial solid waste according to claim 1, characterized in that, The preparation method of the biomineralizing bacterial agent includes: Bacillus pasteurellii was cultured in LB medium at 20-30°C to obtain a bacterial suspension with a concentration of 10. 8 ~10 9 CFU / mL; The bacterial solution and urease were mixed at a volume ratio of (4~6):1 to obtain the biomineralizing bacterial agent.

5. The soft soil consolidation and remediation material based on industrial solid waste according to claim 1, characterized in that, The preparation method of the amphoteric polymeric flocculant includes: Acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride were added to water at a molar ratio of (3~4):(1~2):1 to obtain a third mixture. An initiator was added to the third mixture, and polymerization was initiated at 50~60℃ to obtain an amphoteric polymer flocculant. The mass of the initiator added was 0.1%~0.2% of the total mass of acrylamide, acrylic acid, and dimethyl diallyl ammonium chloride.

6. The soft soil consolidation and remediation material based on industrial solid waste according to claim 1, characterized in that, The preparation method of the crack-resistant and water-retaining composite agent includes: Hydroxypropyl methylcellulose and polyvinyl alcohol fiber were mixed at a mass ratio of (3~5):1 to obtain an anti-crack and water-retaining composite agent. The preparation method of the ecological restoration agent includes: An ecological restoration agent is prepared by mixing humic acid, slow-release compound fertilizer and arbuscular mycorrhizal fungal spores at a mass ratio of (3~5):(2~3):

1.

7. The soft soil consolidation and remediation material based on industrial solid waste according to claim 1, characterized in that, The mixing water is an aqueous solution of calcium nitrate with a mass fraction of 0.5% to 1%.

8. A method for preparing a soft soil solidification and remediation material based on industrial solid waste according to any one of claims 1-7, characterized in that, include: The main mixture is prepared by mixing vanadium slag-boron mud composite material, municipal sludge-dredging sludge composite material, waste ceramic powder and mixing water. Modified steel slag powder, metakaolin-silica composite material, alkali activator and mixing water are added to the main mixture to obtain a solidified mixture; After adding nanocomposite adsorbent, amphoteric polymer flocculant, crack-resistant and water-retaining composite agent, ecological restoration agent and mixing water to the solidified mixture and mixing evenly, biomineralizing bacteria are added to obtain soft soil solidification and repair material.