A method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection

Abstract

This invention discloses a method for efficiently utilizing tunnel waste to prepare vegetated concrete ecological slope protection. The method includes the following steps: manual screening of waste samples; pretreatment of the waste; preparation of a graft copolymer water-reducing agent; preparation of coal-based porous carbon material; preparation of a carrier and composite microbial agent for coal-based humic acid microbial fertilizer, followed by mixing to obtain coal-based humic acid fertilizer; preparation of B-doped modified g-C3N4; preparation of a photocatalytic porous carbon precursor; weighing raw materials according to a preset mass fraction to prepare recycled concrete; pouring the recycled concrete, and then pouring a photocatalytic coal-based porous carbon turbid liquid onto the concrete surface, followed by sowing of a mixture of tall fescue and bermudagrass seeds. This invention achieves a synergistic effect in the conversion of waste, improving the overall economic benefits of waste resource conversion.

Description

Technical Field

[0001] This invention relates to the field of building materials and concrete technology, and more specifically, to a method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection. Background Technology

[0002] Industrial production processes generate a large amount of waste. However, due to the high intensity of industrial waste generation and its insufficient utilization, it not only pollutes the ecological environment but also wastes a significant amount of resources. Currently, various innovative research and developments have been made on industrial waste, such as the full resource utilization of solid wastes like tailings, fly ash, waste soil and rock, and waste tires in highway engineering; grouting treatment materials for solid waste-based limestone aquifers; coal gangue resource utilization technology; and the use of tunnel waste for highway subgrade filling and the production of manufactured sand and cement bricks. However, tunnel waste presents challenges such as poor pollution mobility and diffusion, strong persistence, complex sources, varying rock characteristics, and a high amount of impurities like soil inclusions, potentially leading to compound and secondary pollution. Therefore, the reuse of tunnel waste requires a comprehensive consideration of its generation characteristics, compositional characteristics, types of alternative raw materials, and uses. A reasonable and scientific assessment of ecological and environmental risks is needed, along with simple and efficient extraction of necessary substances to achieve green resource reuse from multiple perspectives.

[0003] In recent years, humic acid, as an important organic carbon resource and petroleum substitute, has attracted increasing attention in fields such as environmental remediation, chemical synthesis, and the preparation of functional carbon materials. Coal-based humic acid is generally extracted from peat and weathered coal, but this method suffers from problems such as low extraction rates, high acid and alkali consumption, high costs, and severe pollution. If traditional coal-based humic acid extraction technology is used on the tunnel waste selected in this paper, its reuse feasibility is low and the expected results cannot be achieved. Therefore, finding green, environmentally friendly, stable, inexpensive, and highly efficient extraction processes and expanding the application areas of humic acid will be important directions for humic acid research.

[0004] Porous carbon materials have the characteristics of high specific surface area, adjustable pore size, excellent electrochemical performance and environmental friendliness. They are mainly used in water treatment, air purification, industrial decolorization and other fields. They are effective in absorbing CO2 and various heavy metals and organic pollutants in water, which helps to reduce the carbon footprint of vegetated concrete and provide a more suitable and reliable environment for plant growth in vegetated concrete. However, the specific surface area and pore volume of porous carbon prepared by existing technologies are generally low, resulting in low cost performance.

[0005] Photocatalytic degradation technology utilizes photocatalytic materials to oxidize and degrade organic matter and pollutants through electron transitions generating oxidative holes under light irradiation. Currently, photocatalytic degradation plays a significant role in environmental pollution control. However, current research largely focuses on TiO2 and ZnO materials, whose preparation processes and costs are relatively high, and their stability needs improvement.

[0006] Currently, coal-based humic acid fertilizers have a wide range of applications and significant effects in agricultural production. Their excellent efficacy has been verified by scientific research and production practice in many aspects, such as improving soil, providing a variety of balanced microorganisms, increasing fertilizer utilization, increasing crop yield and quality, enhancing crop performance (disease resistance, stress resistance, drought resistance), and eliminating soil and agricultural product pollution. Compared with general fertilizers, the humic acid component in coal-based humic acid fertilizers has a particularly significant effect on stimulating crop growth and enhancing crop stress and disease resistance. Considering that the soil environment in some construction sections of the long-distance railway is not fertile, the soil nutrient content is relatively simple and thin, and the influence of harsh climatic conditions may not be able to meet the normal growth and development of general vegetated concrete plants, coal-based humic acid extracted from tunnel waste was selected to make fertilizer in order to provide sufficient nutrients and suitable growth conditions for the selected plants.

[0007] As environmental problems become increasingly severe, climate change and pollution are impacting human production and lives. The CO2 greenhouse effect is a major cause of global environmental issues. The cement industry, as one of the sectors with high carbon emissions and energy consumption, must actively engage in industrial transformation and upgrading to improve the quality of economic growth and achieve green production capacity development. Therefore, there is an urgent need to develop and innovate a series of new green and low-carbon building materials, adhering to the concept of green reuse, and preparing vegetation-modified concrete ecological slope protection suitable for construction sites. This will improve the performance of building materials while reducing their carbon footprint, thus promoting the sustainable development of the cement and building materials industry.

[0008] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0009] (a) Technical problems to be solved

[0010] To address the shortcomings of existing technologies, this invention provides a method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection. This method has the advantage of achieving the superposition of spoil conversion benefits and improving the overall economic benefits of spoil resource conversion. It also solves the problem that the soil environment in the construction section is not fertile, the soil nutrient content is relatively simple and thin, and the harsh climate may prevent the normal growth and development of plants in general vegetated concrete.

[0011] (II) Technical Solution

[0012] To achieve the combined benefits of waste slag conversion and improve the overall economic efficiency of waste slag resource conversion, the specific technical solution adopted in this invention is as follows:

[0013] A method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection, the method comprising the following steps:

[0014] S1: Manually screen the waste samples brought from the construction site;

[0015] S2. Pre-treat the waste residue;

[0016] S3. Graft copolymer water-reducing agent prepared using coal-based humic acid as raw material;

[0017] S4. Using coal-based humic acid as raw material, KOH and HCl were added, followed by ultrasonic stirring and carbonization protection to prepare coal-based porous carbon materials.

[0018] S5. Prepare the carrier and compound microbial agent for coal-based humic acid microbial fertilizer and mix them to obtain coal-based humic acid fertilizer.

[0019] S6. Dicyandiamine is placed in a crucible and then ground, cleaned, dried and ground again to prepare B-doped modified g-C3N4.

[0020] S7. Photocatalytic porous carbon precursors were prepared from coal-based porous carbon and B-doped modified g-C3N4 using a photocatalytic loading method.

[0021] S8. Weigh the raw materials according to the preset mass fraction and prepare recycled concrete;

[0022] S9. Pour the recycled concrete and pour the photocatalytic coal-based porous carbon turbid liquid onto the concrete surface, then sow a mixture of tall fescue and bermudagrass seeds.

[0023] Preferably, the pretreatment of the waste residue includes the following steps:

[0024] S21. Grind the selected waste samples, treat them with acid and alkali, and heat them in a water bath. Cool them to room temperature for later use.

[0025] S22. Adjust the pH value and put it into the fully automatic methane fermentation potential test system for methane fermentation. When the daily gas production reaches 0 mL, terminate the fermentation experiment and dry the fermentation residue for later use.

[0026] S23. Place the treated waste sample and fermentation residue in a beaker for heating and centrifugation, adjust the pH of the filtrate to 2-3, extract the lower precipitate, and then place it in an 80℃ drying oven to constant weight to obtain the product to be tested.

[0027] Preferably, the lower precipitate is humic acid.

[0028] Preferably, the graft copolymer water-reducing agent is a black, viscous substance.

[0029] Preferably, the preparation of coal-based porous carbon includes the following steps:

[0030] S41. First add KOH, then add the extracted humic acid, stir at room temperature until fully dissolved, then add HCl dropwise, then sonicate and stir for 3-4 hours, and then dry the mixed solution thoroughly to obtain a gel-like substance;

[0031] S42. The gelatinous substance is carbonized under N2 protection. The carbonization process includes: heating from room temperature to 250-300℃ and holding at that temperature for 0.5-2 hours; then continuing to heat to 450-500℃ and holding at that temperature for 1.3-3 hours.

[0032] S43. Cool to room temperature to obtain carbonized products; wash the carbonized products with deionized water to obtain coal-based porous carbon materials.

[0033] Preferably, the preparation of the carrier and the composite microbial agent for coal-based humic acid microbial fertilizer, and their mixing to obtain the coal-based humic acid fertilizer, includes the following steps:

[0034] S51. According to the preset fraction, coal-based humic acid, amino acids, organic materials, phosphorus and potassium fertilizers, manganese sulfate and silicon dioxide are mixed and added to a granulation dryer, and reacted at 80-250℃ for 2-6 hours to obtain a carrier for coal-based humic acid microbial fertilizer.

[0035] S52. Mix Bacillus subtilis fermentation broth, lactic acid bacteria fermentation broth and green sulfur bacteria fermentation broth to obtain a compound microbial agent;

[0036] S53. The carrier of coal-based humic acid microbial fertilizer is mixed with a compound microbial agent, so that the compound microbial agent is adsorbed in the carrier, and then naturally air-dried to obtain coal-based humic acid fertilizer.

[0037] Preferably, the step of loading dicyandiamine into a crucible and subjecting it to grinding, cleaning, drying, and further grinding to prepare B-doped modified g-C3N4 includes the following steps:

[0038] S61. Weigh dicyandiamine and place it in a crucible. Wrap it with aluminum foil and place the crucible in a muffle furnace. Calcinate it at 500℃ for 5 hours. After calcination, place the product in an agate bowl and grind it. Wash the powder obtained from grinding with anhydrous alcohol and distilled water. After washing, dry it in an oven and grind it again to obtain g-C3N4.

[0039] S62. Weigh g-C3N4 and boric acid separately and add them to the ball mill jar. Seal the ball mill jar tightly, turn on the planetary high-energy ball mill, and ball mill at a speed of 400 r / min for 3 hours.

[0040] S63. Take out the sample from the planetary high-energy ball mill and pour it into a crucible. Wrap it with aluminum foil and put it into a muffle furnace. Then, calcine it at 400℃ for 3 hours and then close the muffle furnace. After it has completely cooled down, take out the sample and grind it through a 120-mesh sieve to obtain B-doped modified g-C3N4.

[0041] Preferably, the preparation of the photocatalytic porous carbon precursor based on coal-based porous carbon and B-doped modified g-C3N4 using a photocatalytic loading method includes the following steps:

[0042] S71. Immerse coal-based porous carbon in NaOH aqueous solution and sonicate for 30 min.

[0043] S72. Place the treated coal-based porous carbon into a 0.1MPa vacuum saturated container for 30 minutes;

[0044] S73. Disperse g-C3N4 in anhydrous ethanol and stir magnetically to disperse it at different concentrations. After vacuum suction and magnetic stirring for 30 minutes, draw the g-C3N4 anhydrous ethanol dispersion into a vacuum saturated container and sonicate it for 1 hour.

[0045] S74. Take out the photocatalytic coal-based porous carbon, wash it with distilled water, and dry it at 105℃ for 3 hours.

[0046] Preferably, the raw materials weighed according to a preset mass fraction to prepare recycled concrete are: 15-30 parts low-calcium carbonized cement, 2-6 parts limestone powder, 90-160 parts coarse aggregate, 30-60 parts fine aggregate, a water-cement ratio of 0.26-0.35 parts, 0.1-0.8 parts admixture, 4-10 parts water, and 3-5 parts porous carbon material.

[0047] Preferably, the process of pouring recycled concrete, applying photocatalytic coal-based porous carbon turbid liquid to the concrete surface, and then sowing a mixture of tall fescue and bermudagrass seeds includes the following steps:

[0048] S91. First, remove weeds, fallen leaves, dead branches, loose soil and loose stones from the slope, and then pour recycled concrete into the hopper.

[0049] S92. Move the concrete into the cabinet frame by crane for pouring. Weigh out the photocatalytic coal-based porous carbon and put it into a beaker. Add an appropriate amount of distilled water and stir with a glass rod to form a uniform turbid liquid. After the concrete is poured, pour the turbid liquid in the beaker onto the concrete surface 1 hour before the initial setting.

[0050] S93. After the concrete has set, sow a mixture of tall fescue and bermudagrass seeds on the concrete surface, with a sowing rate of 30g per square meter.

[0051] S94. After sowing, cover the surface with planting soil and then cover the surface with non-woven fabric. Water and fertilize regularly after planting tall fescue and bermudagrass.

[0052] (III) Beneficial Effects

[0053] Compared with existing technologies, this invention provides a method for efficiently preparing vegetated concrete ecological slope protection using tunnel spoil, which has the following beneficial effects:

[0054] (1) This invention takes the waste from the construction of long railway tunnels as the research object, and studies the efficient and full utilization of humic acid extracted by alkali dissolution and acid precipitation through methane fermentation and pre-treated methane fermentation. Through the graded transformation of chemical components and organic matter, the transformation benefits of waste are superimposed, and the overall economic benefits of waste resource transformation are improved.

[0055] (2) This invention makes full use of the existing waste from the construction of long railway tunnels, studies its ecological, environmental and economic value, and efficiently utilizes the main components in the waste through various methods to extract coal-based humic acid and make a variety of materials such as humic acid water-reducing agent, porous carbon material and humic acid fertilizer. These materials are used in the preparation of vegetation concrete. The materials are easy to obtain and save a lot of unnecessary resources. At the same time, it also solves the problem of where to dispose of construction waste and the high cost of disposal.

[0056] (3) The ecological slope protection construction method provided by the present invention uses humic acid water-reducing agent, porous carbon material, humic acid fertilizer, cement, aggregate, admixture, water and other raw materials. It not only plays the role of slope reinforcement and preventing soil erosion, but also the vegetation concrete has a porous structure and low alkalinity environment, which can adapt to the growth of green plants, and plays the role of greening the environment and ecological restoration. It has good economic, social and ecological benefits.

[0057] (4) The porous carbon material made from construction waste can absorb CO2 and various heavy metals and organic pollutants in water, which helps to reduce the carbon footprint of vegetated concrete and provide a more suitable and reliable environment for plant growth.

[0058] (5) The present invention addresses the issue that excavated materials from engineering construction are often discarded as waste, which not only occupies land resources but also affects the environment. Properly handling the relationship between engineering construction and ecological protection and realizing the resource utilization of engineering waste is an inevitable requirement for building green projects. In response to the problem of large amounts of engineering construction waste and the demand for sand and gravel aggregates, the present invention utilizes engineering waste to prepare sand and gravel aggregates, which not only consumes engineering waste but also solves the problem of sand and gravel aggregates for engineering construction, thus realizing the resource utilization of engineering waste. The sand and gravel aggregate preparation technology is developing rapidly, and new equipment and key technologies are constantly being introduced. By rationally selecting sand and gravel aggregate processing technology and equipment, and by strengthening quality control, high-quality sand and gravel aggregates can be provided for engineering construction.

[0059] (6) The present invention combines concrete and carbon nitride to make photocatalytic concrete, which is applied to the degradation of air pollutants, mainly NO, and is a feasible method for treating air pollution problems.

[0060] (7) The present invention uses a loading method to prepare photocatalytic porous carbon, which is loaded onto the surface of cement paste during initial setting. Using porous carbon as an intermediate of g-C3N4 can significantly improve photocatalytic activity. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a flowchart of a method for efficiently preparing vegetated concrete ecological slope protection using tunnel waste according to an embodiment of the present invention. Detailed Implementation

[0063] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0064] According to an embodiment of the present invention, a method for efficiently preparing vegetated concrete ecological slope protection using tunnel spoil is provided.

[0065] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 As shown, according to an embodiment of the present invention, a method for efficiently preparing vegetated concrete ecological slope protection using tunnel spoil includes the following steps:

[0066] S1: Manually screen the waste samples brought from the construction site;

[0067] It should be noted that the waste samples from the above-mentioned construction site were waste from the construction of tunnels for the Changda Railway, and they had a high content of humic acid.

[0068] S2. Pre-treat the waste residue;

[0069] The pretreatment of the waste residue includes the following steps:

[0070] S21. Grind the selected waste samples, treat them with acid and alkali, and heat them in a water bath. Cool them to room temperature for later use.

[0071] It should be noted that the above grinding standard refers to grinding the waste residue to 100 mesh;

[0072] Acid pretreatment: Accurately weigh 30g of 100-mesh residue into a beaker, add 150mL of 5% H2SO4 solution (solid-liquid ratio 1:5), heat in a 100℃ water bath for 120min, and cool to room temperature for later use;

[0073] Alkali pretreatment: Accurately weigh 30g of 100-mesh residue into a beaker, add 360mL of 3% NaOH solution (solid-liquid ratio 1:12), heat in a 70℃ water bath for 110min, and cool to room temperature for later use;

[0074] S22. Adjust the pH value and put it into the fully automated methane fermentation potential testing system (AMPTSⅡ) for methane fermentation. When the daily gas production reaches 0 mL, terminate the fermentation experiment and dry the fermentation residue for later use.

[0075] It should be noted that the methane fermentation process involves placing the pretreated liquid after acid and alkali pretreatment of the waste residue into a fermentation bottle, adjusting the pH to 6.9-7.1, adding 150 mL of activated sludge, adjusting the pH to 6.9-7.1 again, sealing the bottle, and placing it in a fully automated methane fermentation potential testing system (AMPTSⅡ). The methane fermentation experiment is conducted at 50°C, and the fermentation experiment is terminated when the daily gas production reaches 0 mL. The fermentation residue is dried for later use, and three parallel sets are performed.

[0076] S23. Place the treated waste sample and fermentation residue in a beaker for heating and centrifugation, adjust the pH of the filtrate to 2-3, extract the lower precipitate, and then place it in an 80℃ drying oven to constant weight to obtain the product to be tested.

[0077] It should be noted that the lower precipitate mentioned above is humic acid;

[0078] The extraction method for the lower precipitate is as follows: Weigh 10g of 100-mesh waste residue, methane fermentation residue, and acid-pretreated methane fermentation waste residue into beakers, add 40mL of 5% NaOH solution (solid-liquid ratio 1:4) to each, soak for 24h, then add 200mL of distilled water (solid-liquid ratio 1:20), heat and stir at 80℃ for 2h; repeatedly centrifuge to obtain the supernatant; then adjust the pH of the filtrate to 2-3 using 5% H2SO4, HNO3, HCl, and H3PO4 solutions respectively, and take the lower precipitate (humic acid) and dry it in an 80℃ oven to constant weight to obtain the product for analysis.

[0079] The steps for determining the humic acid content are as follows: Weigh 0.2g of dried humic acid sample (70-80 mesh), dissolve it in 1% NaOH to 100mL, filter out the first 10mL of filtrate, take 5mL of the filtrate into a 250mL Erlenmeyer flask, add 75mL of K2Cr2O (0.4mol / L) and 15mL of concentrated sulfuric acid in sequence, place it in a boiling water bath for 30min, heat to oxidize, cool to room temperature, add 3-5 drops of o-phenanthroline indicator solution, and then titrate with ferrous ammonium sulfate standard solution. The endpoint is when the solution turns brick red. Record the amount of ferrous ammonium sulfate consumed, and perform a blank test at the same time.

[0080] S3. Graft copolymer water-reducing agent prepared using coal-based humic acid as raw material;

[0081] Among them, coal-based humic acid (CHA), as an important petroleum substitute, is not only abundant in resources, but also has high aromaticity, high rigidity, and contains abundant active groups such as carboxyl and phenolic hydroxyl groups. It is easy to introduce sulfonic acid groups and polycondensation, making it a potential raw material for the synthesis of high-efficiency water-reducing agents.

[0082] Specifically, using coal-based humic acid as raw material, the corresponding graft copolymer water-reducing agent is prepared by aqueous phase free radical copolymerization of sodium 2-acrylamide-2-methylpropanesulfonate (AMPS) and acrylic acid (AA).

[0083] The graft copolymer water-reducing agent OHA-g-ATBS-co-AA or NHA-g-ATBS-co-AA is a black viscous substance.

[0084] It should be noted that the above graft copolymerization introduces adsorption groups such as carboxyl and sulfonic acid groups, and increases the molecular weight to improve the dispersion performance of OHA;

[0085] The above-mentioned AA copolymer can increase the carboxyl content, promote the adsorption of graft copolymers and improve the electrostatic repulsion of the adsorption layer, thereby improving the fluidity and water-reducing effect of cement paste;

[0086] S4. The pretreated waste residue is mixed with ethanol and sucrose and ball-milled to prepare coal-based porous carbon.

[0087] The preparation of coal-based porous carbon includes the following steps:

[0088] S41. First add KOH, then add the extracted humic acid, stir at room temperature until fully dissolved, then add HCl dropwise, then sonicate and stir for 3-4 hours, and then dry the mixed solution thoroughly to obtain a gel-like substance;

[0089] Preferably, KOH is added first to adjust the pH to 9-10, then coal-based humic acid is added, and then HCl is added dropwise to adjust the pH to 1-2;

[0090] S42. The gelatinous substance is carbonized under N2 protection. The carbonization process includes: heating from room temperature to 250-300℃ and holding at that temperature for 0.5-2 hours; then continuing to heat to 450-500℃ and holding at that temperature for 1.3-3 hours.

[0091] S43. Cool to room temperature to obtain carbonized products; wash the carbonized products with deionized water to obtain coal-based porous carbon materials.

[0092] Preferably, the mesopority of the porous carbon material reaches 86% or more.

[0093] The porous carbon material was further activated to obtain carbon material for supercapacitors.

[0094] The activation process of the above-mentioned porous carbon materials includes the following steps:

[0095] The porous carbon material is ground to 150-300 mesh, mixed with KOH solution, and sonicated to uniformly disperse the solid powder in the solution. Then, the temperature is gradually increased from room temperature to 150-200℃ for drying.

[0096] Then, activation is performed under N2 conditions. The temperature is increased from room temperature to 600-800℃ and held for 1-3 hours, then cooled to room temperature. The material is then washed with hydrochloric acid and stirred until neutral, yielding carbon material for supercapacitors. The N2 flow rate is 50-65 mL / min.

[0097] S5. Prepare the carrier and compound microbial agent for coal-based humic acid microbial fertilizer and mix them to obtain coal-based humic acid fertilizer.

[0098] The preparation of the carrier and composite microbial agent for coal-based humic acid microbial fertilizer, and their mixing to obtain the coal-based humic acid fertilizer, includes the following steps:

[0099] S51. According to the preset fraction, coal-based humic acid, amino acids, organic materials, phosphorus and potassium fertilizers, manganese sulfate and silicon dioxide are mixed (mixed by stirring for 2 hours) and then added to a granulation dryer. After reacting at 80-250℃ (preferably 150℃) for 2-6 hours (preferably 4 hours), a carrier for coal-based humic acid microbial fertilizer is obtained.

[0100] It should be noted that the above-mentioned amino acid is one of proline, aspartic acid, or glutamic acid.

[0101] The aforementioned organic materials are straw or livestock and poultry manure;

[0102] Specifically, 40% of the prepared coal-based humic acid, 25% aspartic acid, 20% straw, 5% nitrogen, phosphorus and potassium fertilizer, 5% manganese sulfate and 5% silicon dioxide are mixed and stirred for 2 hours. Then, the mixture is added to a granulator and dryer and reacted at 150°C for 4 hours to obtain the carrier of coal-based humic acid microbial fertilizer.

[0103] S52. Mix Bacillus subtilis fermentation broth, lactic acid bacteria fermentation broth and green sulfur bacteria fermentation broth to obtain a compound microbial agent;

[0104] Specifically, 5g of glucose, 5g of beef extract, 10g of peptone, 5g of NaCl, and 1L of distilled water were mixed, the pH was adjusted to 7.0, and sterilized to obtain a liquid culture medium. Bacillus subtilis, lactic acid bacteria, and green sulfur bacteria preserved in slant culture medium were transferred to the prepared liquid culture medium and cultured separately at 37℃ and 250 r / min for 36 h. The obtained bacterial strains were then added back to the prepared liquid culture medium for amplification and cultured at 37℃ and 250 r / min for 36 h to obtain the fermentation broths. The fermentation broths of each strain were then mixed at a mass ratio of 4:3:1 to obtain a compound microbial agent.

[0105] It should be noted that the method for preparing Bacillus subtilis fermentation broth, lactic acid bacteria fermentation broth, or green sulfur bacteria fermentation broth is as follows: Bacillus subtilis, lactic acid bacteria, or green sulfur bacteria are inoculated into a liquid culture medium for preliminary culture to obtain seed liquid, and then added to a liquid culture medium for further culture.

[0106] The compound microbial agent is a mixture of Bacillus subtilis fermentation broth, lactic acid bacteria fermentation broth and green sulfur bacteria fermentation broth in a mass ratio of 2-5:2-5:1, with a preferred mass ratio of 4:3:1.

[0107] S53. The carrier of coal-based humic acid microbial fertilizer is mixed with a compound microbial agent, so that the compound microbial agent is adsorbed in the carrier, and then naturally air-dried to obtain coal-based humic acid fertilizer.

[0108] Specifically, the carrier of coal-based humic acid microbial fertilizer is mixed with the compound microbial agent at a mass ratio of 5:1, so that the compound microbial agent is adsorbed in the carrier, and then naturally air-dried to obtain coal-based humic acid fertilizer.

[0109] S6. Dicyandiamine is placed in a crucible and then ground, cleaned, dried and ground again to prepare B-doped modified g-C3N4.

[0110] Specifically, the step of loading dicyandiamine into a crucible and then grinding, cleaning, drying, and grinding again to prepare B-doped modified g-C3N4 includes the following steps:

[0111] S61. Weigh 50g of dicyandiamine and put it into a crucible. Wrap it with aluminum foil and place the crucible in a muffle furnace. Calcinate it at 500℃ for 5 hours. After calcination, put the product into an agate bowl and grind it. Wash the powder obtained by grinding with anhydrous alcohol and distilled water. After washing, put it into an oven to dry and then grind it again to obtain g-C3N4.

[0112] Among them, g-C3N4 is a graphene-like two-dimensional semiconductor photocatalytic material. Its preparation process is relatively simple and the raw materials are inexpensive. Furthermore, its high stability has made it a hot research topic in the field of photocatalysis. Therefore, this paper uses g-C3N4 as a photocatalytic material to replace traditional TiO2 and ZnO in concrete, and uses porous carbon concrete prepared with coal-based humic acid as a support for the photocatalyst. This can provide a reference for the development and application of photocatalytic concrete.

[0113] It should be noted that the calcination at 500℃ for 5 hours was achieved by increasing the temperature to 500℃ at a rate of 10°C / min.

[0114] After calcination, the product is placed in an agate bowl and ground, and then cooled to room temperature.

[0115] S62. Weigh 100g of g-C3N4 and 10g of boric acid respectively and add them to the ball mill jar. Seal the ball mill jar tightly, turn on the planetary high-energy ball mill, and ball mill at a speed of 400r / min for 3h.

[0116] S63. Take out the sample from the planetary high-energy ball mill and pour it into a crucible. Wrap it with aluminum foil and place it in a muffle furnace. Then, calcine it at 400℃ for 3 hours and then turn off the muffle furnace. After it has completely cooled down, take out the sample and grind it through a 120-mesh sieve to obtain B-doped modified g-C3N4.

[0117] Among them, the B-doped modified g-C3N4 exhibits high photocatalytic performance because during ball milling, the g-C3N4 powder undergoes severe plastic deformation due to intense collisions, resulting in severe lattice distortion and a significant increase in internal defects, thus enhancing the catalyst's activity. Simultaneously, the ball milling process generates a large amount of heat, and the mechanical force forces the separation of boric acid from B. 3+ It diffuses into the distorted lattice, forming a new boron-doped photocatalyst, thereby improving photocatalytic performance.

[0118] S7. Photocatalytic porous carbon precursors were prepared from coal-based porous carbon and B-doped modified g-C3N4 using a photocatalytic loading method.

[0119] Specifically, the preparation of the photocatalytic porous carbon precursor based on coal-based porous carbon and B-doped modified g-C3N4 using a photocatalytic loading method includes the following steps:

[0120] S71. Immerse the coal-based porous carbon in a 0.1 mol / L NaOH aqueous solution and sonicate for 30 min.

[0121] It should be noted that the ultrasonic treatment for 30 minutes is to obtain more active sites.

[0122] S72. Place the treated coal-based porous carbon into a 0.1MPa vacuum saturated container for 30 minutes;

[0123] It should be noted that the treated coal-based porous carbon was placed in a 0.1 MPa vacuum saturated container for 30 minutes to remove air from the pores of the porous carbon.

[0124] S73. Disperse g-C3N4 in 100mL of anhydrous ethanol and stir magnetically to disperse it at different concentrations. After vacuum suction and magnetic stirring for 30 minutes, draw the g-C3N4 anhydrous ethanol dispersion into a vacuum saturated container and sonicate for 1 hour.

[0125] S74. Take out the photocatalytic coal-based porous carbon, wash it with distilled water, and dry it at 105℃ for 3 hours.

[0126] S8. Weigh the raw materials according to the preset mass fraction and prepare recycled concrete;

[0127] Specifically, the raw materials weighed according to the preset mass fraction and their mass fraction in the preparation of recycled concrete are as follows: 15-30 parts of low-calcium carbonized cement, 2-6 parts of limestone powder, 90-160 parts of coarse aggregate, 30-60 parts of fine aggregate, water-cement ratio of 0.26-0.35 parts, admixture of 0.1-0.8 parts, water of 4-10 parts, and porous carbon material of 3-5 parts.

[0128] It should be noted that the calcium carbonate content in the limestone powder is ≥60%, and the specific surface area is ≥300 kg / cm². 2 ;

[0129] The coarse aggregate is medium stone, 9.5-19mm;

[0130] The content of g-C3N4 in fine aggregate is ≤0.8%;

[0131] The admixture is a graft copolymer water-reducing agent;

[0132] The porous carbon material is coal-based porous carbon.

[0133] S9. Pour the recycled concrete and pour the photocatalytic coal-based porous carbon turbid liquid onto the concrete surface, then sow a mixture of tall fescue and bermudagrass seeds.

[0134] Specifically, the process of pouring recycled concrete, applying photocatalytic coal-based porous carbon turbid liquid to the concrete surface, and then sowing a mixture of tall fescue and bermudagrass seeds includes the following steps:

[0135] S91. First, remove weeds, fallen leaves, dead branches, loose soil and loose stones from the slope, and then pour recycled concrete into the hopper.

[0136] It should be noted that the slope ratio is 1:1-1.5;

[0137] S92. Move the concrete into the cabinet frame by crane for pouring. Weigh out the photocatalytic coal-based porous carbon and put it into a beaker. Add an appropriate amount of distilled water and stir with a glass rod to form a uniform turbid liquid. After the concrete is poured, pour the turbid liquid in the beaker onto the concrete surface 1 hour before the initial setting.

[0138] It should be noted that the pouring needs to be completed within 20-60 minutes;

[0139] S93. After the concrete has set, sow a mixture of tall fescue and bermudagrass seeds on the concrete surface, with a sowing rate of 30g per square meter.

[0140] S94. After sowing, cover the surface with planting soil and then cover the surface with non-woven fabric. Water and fertilize regularly after planting tall fescue and bermudagrass.

[0141] It should be noted that the fertilizer used is a coal-based humic acid type functional microbial fertilizer.

[0142] In summary, by utilizing the above-mentioned technical solutions of this invention, this invention takes the construction waste from long railway tunnels as the research object, and studies the efficient and full utilization of humic acid extracted by the alkali dissolution and acid precipitation method through methane fermentation and pre-treated methane fermentation. Through the graded transformation of chemical components and organic matter, the transformation benefits of the waste are superimposed, thereby improving the overall economic benefits of waste resource transformation. This invention makes full use of existing construction waste from long railways, studies its ecological, environmental, and economic value, and efficiently utilizes the main components in the waste through various methods to extract coal-based humic acid, and produces various materials such as humic acid-based water-reducing agents, porous carbon materials, and humic acid fertilizers, which are then used in the preparation of vegetated concrete. The materials are readily available, saving a significant amount of unnecessary resource consumption, and also solving the problems of where to dispose of construction waste and the high cost of disposal. The ecological slope protection construction method provided by this invention uses humic acid-based water-reducing agents, porous carbon materials, humic acid fertilizers, cement, aggregates, admixtures, and water as raw materials. It not only strengthens slopes and prevents soil erosion, but the vegetated concrete has a porous structure and a low-alkalinity environment, which can adapt to the growth of green plants, achieving the effects of greening the environment and ecological restoration, and has good economic, social, and ecological benefits. The porous carbon materials made from construction waste can absorb CO2 and various heavy metals and organic pollutants in the water, which helps to reduce the carbon footprint of vegetated concrete and provide a more suitable and reliable environment for plant growth. Construction excavation materials are often discarded as waste, which not only occupies land resources but also affects the environment. Properly handling the relationship between engineering construction and ecological protection, and realizing the resource utilization of engineering waste, is an essential requirement for building green projects. Addressing the issue of large quantities of engineering waste and high demand for sand and gravel aggregates, this invention utilizes engineering waste to prepare sand and gravel aggregates, thus consuming the waste and solving the problem of sand and gravel aggregate supply for engineering construction, achieving resource utilization of engineering waste. Sand and gravel aggregate preparation technology is rapidly developing, with new equipment and key technologies constantly emerging. Rational selection of sand and gravel aggregate processing technology and equipment, along with strengthened quality control, ensures the supply of high-quality sand and gravel aggregates for engineering construction. This invention combines concrete and carbon nitride to create photocatalytic concrete for degrading air pollutants, representing a feasible method for addressing air pollution. This invention uses a loading method to prepare photocatalytic porous carbon, which is then loaded onto the surface of cement paste during initial setting. Using porous carbon as an intermediate for g-C3N4 significantly improves photocatalytic activity.

[0143] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection, characterized in that, The method includes the following steps: S1: Manually screen the waste samples brought from the construction site; S2. Pre-treat the waste residue; The pretreatment of the waste residue includes the following steps: S21. Grind the selected waste samples, treat them with acid and alkali, and heat them in a water bath. Cool them to room temperature for later use. S22. Adjust the pH value and put it into the fully automatic methane fermentation potential test system for methane fermentation. When the daily gas production reaches 0 mL, terminate the fermentation experiment and dry the fermentation residue for later use. S23. Place the treated waste residue sample and fermentation residue in a beaker for heating and centrifugation, adjust the pH of the filtrate to 2-3, extract the lower precipitate, which is coal-based humic acid, and then dry it in an 80℃ drying oven to constant weight to obtain the product to be tested. S3. Graft copolymer water-reducing agent prepared using some coal-based humic acid as raw material; S4. Using some coal-based humic acid as raw material, KOH and HCl were added, followed by ultrasonic stirring and carbonization protection to prepare coal-based porous carbon material. S5. Prepare the carrier and compound microbial agent for coal-based humic acid microbial fertilizer and mix them to obtain coal-based humic acid fertilizer. S6. Preparation of B-doped modified g-C3N4, the preparation steps are as follows: S61. Weigh dicyandiamine and put it into a crucible. Wrap it with aluminum foil and place the crucible in a muffle furnace. Calcinate it at 500℃ for 5 hours. After calcination, put the product into an agate bowl and grind it. Wash the powder obtained by grinding with anhydrous alcohol and distilled water. After washing, put it into an oven to dry and grind it again to obtain g-C3N4. S62. Weigh g-C3N4 and boric acid separately and add them to the ball mill jar. Seal the ball mill jar tightly, turn on the planetary high-energy ball mill, and ball mill at a speed of 400 r / min for 3 hours. S63. Take out the sample from the planetary high-energy ball mill and pour it into a crucible. Wrap it with aluminum foil and put it into a muffle furnace. Then, calcine it at 400℃ for 3 hours and then close the muffle furnace. After it has completely cooled down, take out the sample and grind it through a 120-mesh sieve to obtain B-doped modified g-C3N4. S7. Photocatalytic coal-based porous carbon was prepared by photocatalytic loading method based on coal-based porous carbon and B-doped modified g-C3N4. S8. Weigh the raw materials according to the preset mass fraction and prepare recycled concrete; The raw materials are weighed according to a preset mass fraction to prepare recycled concrete. The raw materials and their mass fractions are as follows: 15-30 parts low-calcium carbonized cement, 2-6 parts limestone powder, 90-160 parts coarse aggregate, 30-60 parts fine aggregate, 0.1-0.8 parts admixture, 4-10 parts water, and 3-5 parts porous carbon material; the water-cement ratio is 0.26-0.

35. The porous carbon material is coal-based porous carbon, and the additive is a graft copolymer water-reducing agent; S9. Pour the recycled concrete and pour the photocatalytic coal-based porous carbon turbid liquid onto the concrete surface, then sow a mixture of tall fescue and bermudagrass seeds. The process of pouring recycled concrete, applying photocatalytic coal-based porous carbon turbid liquid to the concrete surface, and then sowing a mixture of tall fescue and bermudagrass seeds includes the following steps: S91. First, remove weeds, fallen leaves, dead branches, loose soil and loose stones from the slope, and then pour recycled concrete into the hopper. S92. Move the concrete into the cabinet frame by crane for pouring. Weigh the photocatalytic coal-based porous carbon and put it into a beaker. Add an appropriate amount of distilled water and stir with a glass rod to form a uniform turbid liquid. After the concrete is poured, pour the turbid liquid in the beaker onto the concrete surface 1 hour before the initial setting. S93. After the concrete has set, sow a mixture of tall fescue and bermudagrass seeds on the concrete surface, with a sowing rate of 30g per square meter. S94. After sowing, cover the surface with planting soil and then cover the surface of the planting soil with non-woven fabric. After planting tall fescue and bermudagrass, water and fertilize regularly. The fertilizer is coal-based humic acid fertilizer.

2. The method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection according to claim 1, characterized in that, The graft copolymer water-reducing agent is a black, viscous substance.

3. The method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection according to claim 1, characterized in that, The preparation of the coal-based porous carbon material includes the following steps: S41. First add KOH, then add the extracted coal-based humic acid. Stir at room temperature until fully dissolved, then add HCl dropwise. Then, ultrasonically disperse and stir for 3-4 hours. Finally, dry the mixed solution thoroughly to obtain a gel-like substance. S42. The gelatinous substance is carbonized under N2 protection. The carbonization process includes: heating from room temperature to 250-300℃ and holding at that temperature for 0.5-2 hours, then continuing to heat to 450-500℃ and holding at that temperature for 1.3-3 hours. S43. Cool to room temperature to obtain carbonized products, and wash the carbonized products with deionized water to obtain coal-based porous carbon materials.

4. The method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection according to claim 1, characterized in that, The preparation of the carrier and composite microbial agent for coal-based humic acid microbial fertilizer, and their mixing to obtain the coal-based humic acid fertilizer, includes the following steps: S51. According to the preset fraction, coal-based humic acid, amino acids, organic materials, phosphorus and potassium fertilizers, manganese sulfate and silicon dioxide are mixed and added to a granulation dryer, and reacted at 80-250℃ for 2-6 hours to obtain a carrier for coal-based humic acid microbial fertilizer. S52. Mix Bacillus subtilis fermentation broth, lactic acid bacteria fermentation broth and green sulfur bacteria fermentation broth to obtain a compound microbial agent; S53. The carrier of coal-based humic acid microbial fertilizer is mixed with a compound microbial agent, so that the compound microbial agent is adsorbed in the carrier, and then naturally air-dried to obtain coal-based humic acid fertilizer.

5. A method for efficiently utilizing tunnel spoil to prepare vegetated concrete ecological slope protection according to claim 1, characterized in that, The preparation of photocatalytic coal-based porous carbon based on coal-based porous carbon and B-doped modified g-C3N4 using a photocatalytic loading method includes the following steps: S71. Immerse coal-based porous carbon in NaOH aqueous solution and sonicate for 30 min; S72. Place the treated coal-based porous carbon into a 0.1MPa vacuum saturated container for 30 minutes; S73. Disperse the B-doped modified g-C3N4 in anhydrous ethanol and stir magnetically to disperse it at different concentrations. After vacuum suction and magnetic stirring for 30 minutes, draw the B-doped modified g-C3N4 anhydrous ethanol dispersion into a vacuum saturated container and sonicate it for 1 hour. S74. Take out the photocatalytic coal-based porous carbon, wash it with distilled water, and dry it at 105℃ for 3 hours.

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