A method for improving the structure of a silt soil and a construction method thereof using microorganisms and solid waste materials

Abstract

The present application belongs to the field of civil engineering, and particularly relates to a plantable slope surface structure for improving silt soil by using microorganisms and solid waste materials and a construction method thereof. The construction method comprises spraying an isolation layer: directly spraying a composite bacteria solution containing heavy metal degrading bacteria on the surface of the original soil of the slope; pouring a slope surface protection framework: uniformly mixing silt, phosphogypsum, fly ash, manganese slag and cement in a certain proportion, and then pouring and forming on the isolation layer through a formwork; stacking a slope surface layer: filling silt compost planting soil and grass seeds into a geotextile ecological bag, and then stacking in the slope surface protection framework. The slope surface structure comprises the isolation layer, the slope surface protection framework on the isolation layer and the geotextile ecological bag filled in the slope surface protection framework. The present application realizes the comprehensive optimization of the strength enhancement of the soil body, the environmental safety improvement and the vegetation adaptability, and provides a green and safe slope surface protection approach for slope engineering.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering construction technology, specifically relating to a vegetationable slope structure and construction method that utilizes microorganisms and solid waste materials to improve silt soil. Background Technology

[0002] Traditional methods of slope backfilling typically use high-quality natural soil, which presents challenges such as limited resources, high costs, and environmental impacts. Firstly, high-quality natural soil resources are becoming increasingly scarce, especially with urbanization, making suitable planting soil for slope backfilling increasingly difficult to obtain. Secondly, the extraction and transportation of natural soil requires significant labor and machinery, and the long-distance transport process incurs high costs. Furthermore, soil spillage and dust during transportation pollute the air, water sources, and surrounding vegetation. Soil extraction can also lead to soil erosion and degradation, affecting the ecological balance of the entire area and increasing the environmental management burden of the project.

[0003] With increasing emphasis on sustainable development and resource recycling, utilizing locally sourced materials and turning waste into treasure, particularly modified silt as planting soil for slopes, has become a research and application hotspot. Modified silt as planting soil not only reduces waste disposal but also provides an economical and efficient solution for slope greening. However, existing silt modification methods still have some problems and limitations, affecting their quality and environmental safety in engineering applications. Most existing silt modification methods only employ one of the physical, chemical, or biological methods, making it difficult to simultaneously improve the soil's mechanical properties, environmental safety, and plant adaptability. Furthermore, the amount of solid waste generated by industry and construction is enormous, and the utilization of solid waste resources is still insufficient. Although some methods attempt to apply solid waste materials to silt modification, existing methods lack sufficient degradation and immobilization measures for heavy metals in the silt, potentially leading to environmental risks in the modified planting soil. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a vegetationable slope structure and construction method for improving silt soil using microorganisms and solid waste materials, so as to solve the problems of unsatisfactory improvement effect caused by the lack of systematicity of existing silt improvement methods, incomplete treatment of heavy metals, and lack of guidance on construction technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A construction method for a vegetationable slope structure that utilizes microorganisms and solid waste materials to improve silt soil includes the following steps:

[0007] Spraying isolation layer: A compound bacterial solution containing heavy metal degrading bacteria is sprayed onto the surface of the undisturbed soil slope. The bacterial solution infiltrates into the slope soil to form a biological heavy metal isolation layer. The heavy metal degrading bacteria include Bacillus subtilis and Thiobacillus ferrooxidans.

[0008] Slope protection framework: After mixing silt, phosphogypsum, fly ash, manganese slag and cement in proportion, the mixture is poured and solidified into a framework of a certain size on the isolation layer through a template to form slope protection.

[0009] Slope surface layer construction: Silt composting soil and grass seeds are filled into geotextile bags and manually piled into the slope protection frame. The silt composting soil is made by fermenting silt with decomposed organic fertilizer, superphosphate and potassium magnesium sulfate fertilizer.

[0010] Furthermore, the silt is mixed with 5%-7% phosphogypsum, 6%-9% fly ash, 4%-6% manganese slag, and 8-10% cement at the on-site mixing plant for no less than 20 minutes. After being mixed evenly, it is poured into a frame beam-type wooden formwork to form a slope protection skeleton. Among them, the phosphogypsum particles are powdery with a diameter ≤5mm, and the fly ash and manganese slag particles have a diameter ≤3mm.

[0011] Furthermore, the silt composting planting soil is made by mixing silt with 2.5%-3.5% of well-rotted organic fertilizer, 1%-1.2% of superphosphate and 0.5%-0.9% of potassium magnesium sulfate fertilizer by mass and then composting and fermenting it.

[0012] Furthermore, in the isolation layer, the moisture content of the undisturbed soil on the slope is controlled to 12%-15%; the amount of compound bacterial solution sprayed onto the undisturbed soil on the slope is 2.1-2.55 L / m². 2 ;

[0013] When preparing the compound bacterial solution, a 2% concentration of Bacillus subtilis bacterial solution and a 4% concentration of Thiobacillus ferrooxidans bacterial solution are prepared separately, and then the two are mixed in a volume ratio of (2-3):(5-5.5) to obtain the compound bacterial solution.

[0014] Furthermore, pond silt is used in the slope protection framework and surface layer of the slope; before mixing, the silt moisture content is reduced to 40%-50% using a filter press, and then the dewatered silt cake is spread in the dewatering zone for drying until the silt moisture content drops to 35%-40%; the daily processing capacity of the filter press is not less than 25m³. 3 The straight-line distance from the dehydration zone to the source of the silt shall not exceed 50m.

[0015] Furthermore, when composting silt for planting, the height of the pile should not exceed 2m, and the top of the pile should be rounded. During the fermentation process, the pile should be turned over every 2-3 days to ensure that the temperature of the pile is maintained within the range of 45℃-65℃. The pile should be left to ferment for no less than 7 days to ensure full fermentation, ultimately forming a uniform, odorless, and loose granular structure.

[0016] Furthermore, ensure that the compound bacterial solution spraying equipment is calibrated to guarantee accurate spraying volume per square meter; after spraying and curing, use a total station and GPS system to conduct detailed measurements of the slope and construct a frame beam-type wooden formwork for the slope; record the slope height as H meters, and when constructing the frame beam-type wooden formwork, set positioning stakes every 5 meters in the horizontal direction, set a horizontal support beam every H / 3 of the slope height in the vertical direction, add a vertical support rod every 2 meters, and add corner timber reinforcement at corners and edges.

[0017] Furthermore, after the surface layer of the slope is constructed, a drainage ditch is set up along the contour line at the toe of the slope, and seepage pipes are installed as needed to ensure drainage function; the length of the toe of the slope is 2-4m; the width of the drainage ditch is 25-35cm, the depth is 15-25cm, and the slope is not less than 1%.

[0018] Furthermore, in the isolation layer, the moisture content of the original soil on the slope is 12.5%, and 0.75L of 2% Bacillus subtilis bacterial solution and 1.5L of 4% Thiobacillus ferrooxidans bacterial solution are sprayed per square meter of original soil on the slope.

[0019] In the slope protection framework, the percentages of each component by mass of the silt are as follows: phosphogypsum 6.0%, fly ash 7.5%, manganese slag 5.0%, and cement 8%.

[0020] The percentages of each component in the surface layer of the slope silt by mass are as follows: 3.0% decomposed organic fertilizer, 1.1% superphosphate, 0.7% potassium magnesium sulfate fertilizer, and a spreading thickness of 30cm.

[0021] This invention also proposes a vegetationable slope structure for improving silt soil using microorganisms and solid waste materials, which is constructed using the aforementioned construction method for a vegetationable slope structure for improving silt soil using microorganisms and solid waste materials, including:

[0022] The isolation layer is formed by spraying a compound bacterial solution onto the original soil of the slope, and allowing the bacteria in the compound bacterial solution to fully penetrate to a certain depth; the compound bacterial solution contains Bacillus subtilis and Thiobacillus ferrooxidans.

[0023] The slope protection frame is set on the isolation layer and is constructed using a frame beam type wooden formwork. The raw materials of the slope protection frame include silt and 5%-7% phosphogypsum, 6%-9% fly ash, 4-6% manganese slag and 8-10% cement by weight of silt.

[0024] The slope surface layer is composed of geotextile bags filled with silt compost planting soil and grass seeds. These geotextile bags are filled in layers into the pre-built slope protection framework, with 2-3 layers laid as needed. The silt compost planting soil contains the following components by mass percentage: 2.5%-3.5% well-rotted organic fertilizer, 1%-1.2% superphosphate, and 0.5%-0.9% potassium magnesium sulfate fertilizer.

[0025] The beneficial effects of this invention are:

[0026] This invention employs a three-layer treatment method for slope planting soil. Different soil layers utilize undisturbed slope soil and silt as raw materials, with the addition of specific modifying materials and functional microorganisms. The isolation layer, treated with heavy metal-degrading bacteria, constructs a stable soil barrier, preventing the downward migration of heavy metals from solid waste while simultaneously enhancing the isolation performance of the underlying soil.

[0027] The slope protection frame serves two purposes: firstly, it resists erosion, and secondly, it acts as a framework. By improving the physical and mechanical properties of pond silt and enclosing it in geotextile bags, it ensures that the geotextile bags do not slide significantly while improving their erosion resistance.

[0028] The surface layer of the slope uses fermented silt compost as planting soil, optimizing the nutrient structure and microbial activity of the silt to provide ideal soil and nutrients for vegetation growth. This invention achieves the improvement and utilization of silt, comprehensively optimizing its strength, environmental safety, and vegetation adaptability. It provides high-performance raw materials for slope engineering, eliminating the need for soil extraction and enabling the comprehensive utilization of solid waste materials such as silt, phosphogypsum, fly ash, and manganese slag, which is beneficial to environmental protection. Attached Figure Description

[0029] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0030] Figure 1 This is a schematic diagram of the structure of the slope planting soil according to an embodiment of the present invention.

[0031] In the diagram: 1-Drainage ditch, 2-Planting layer, 3-Heavy metal isolation layer, 4-Slope protection frame. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art are within the scope of protection of the present invention.

[0033] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0034] A construction method for stabilizing and solidifying silt-covered slope structures using microorganisms and solid waste materials includes the following steps:

[0035] A compound bacterial solution containing heavy metal-degrading bacteria is sprayed onto the undisturbed soil surface. The bacterial solution infiltrates the slope soil to form a biological heavy metal isolation layer. The heavy metal-degrading bacteria include Bacillus subtilis and Thiobacillus ferrooxidans. During spraying, the moisture content of the undisturbed slope soil is controlled at 12%-15%, and the concentrations of Bacillus subtilis and Thiobacillus ferrooxidans are controlled at 2.0% and 4.0%, respectively. The spraying concentration for the undisturbed slope soil is 0.6-0.9 L / m². 2 and 1.5-1.65L / m 2 bacterial solution;

[0036] Slope protection framework construction: The slope protection framework structure is constructed using templates to ensure the high strength and stability of the framework; the percentages of each component by mass of silt are as follows: phosphogypsum 5%-7%, fly ash 6%-9%, manganese slag 4-6%, manganese slag 3%-5%, and cement 8-10%, which are mixed evenly according to the design ratio; during the mixing process, the moisture content of the silt is strictly controlled at 30%-35%, and the moisture content of the overall mixture is controlled at 12%-15%;

[0037] Slope surface layer construction: Silt composting soil and grass seeds are filled into geotextile bags and manually piled into the slope protection framework. The silt composting soil is made by fermenting a mixture of silt, well-rotted organic fertilizer, superphosphate, and potassium magnesium sulfate. The percentage of each component in the silt composting soil by mass is as follows: well-rotted organic fertilizer 2.5%-3.5%, superphosphate 1%-1.2%, and potassium magnesium sulfate 0.5%-0.9%. The slope structure after construction is as follows: Figure 1 As shown.

[0038] This invention also proposes a vegetationable slope structure that utilizes microorganisms and solid waste materials to improve silt soil, comprising:

[0039] An isolation layer is formed by spraying a compound bacterial solution onto the original soil of the slope, and allowing the bacteria in the compound bacterial solution to fully penetrate the soil. The compound bacterial solution contains Bacillus subtilis and Thiobacillus ferrooxidans.

[0040] The slope protection frame is set on the isolation layer and is constructed using a frame beam type wooden formwork. The raw materials of the slope protection frame include silt and 5%-7% phosphogypsum, 6%-9% fly ash, 4-6% manganese slag and 8-10% cement by weight of silt.

[0041] The slope surface layer is composed of geotextile bags filled with silt compost planting soil and grass seeds. These geotextile bags are filled in layers into the pre-built slope protection framework; 2-3 layers are laid as needed. In the silt compost planting soil, the percentage of each component by the silt mass is as follows: well-rotted organic fertilizer 2.5%-3.5%, superphosphate 1%-1.2%, and potassium magnesium sulfate fertilizer 0.5%-0.9%.

[0042] The specific construction method of the present invention will now be described in detail with reference to the embodiments.

[0043] A construction method for using modified silt as planting soil on slopes includes five stages: S1 preliminary preparation, S2 silt dewatering, S3 silt fermentation and modification, S4 slope planting soil construction, and S5 vegetation construction.

[0044] In some embodiments, the specific implementation process of step S1, the preliminary preparation, is as follows:

[0045] S11. Select the location of the dewatering zone; choose a location within 50m around the source of the sludge to shorten the transportation distance and improve work efficiency; conduct topographic surveys and select a flat location that is at least 0.5m higher than the surrounding area as the dewatering zone to ensure smooth drainage.

[0046] S12. Clear the surface vegetation and debris from the site and lay a 10cm gravel cushion layer to increase the stability of the foundation.

[0047] S13. Excavate drainage ditches 30cm wide and 30cm deep around the dewatering area, lined with a waterproof membrane, to drain wastewater generated during dewatering to a volume of not less than 10m³. 3 Wastewater collection tank; the tank body is made of reinforced concrete and the inner wall is coated with anti-seepage paint.

[0048] S14. Selection of belt filter press: Select a belt filter press with a daily processing capacity of not less than 25 cubic meters, and the equipment must have a continuous dewatering function to ensure that the moisture content of the sludge is reduced from 60%-80% to 40%-50%, so as to provide suitable sludge conditions for subsequent modification treatment of sludge.

[0049] S15. Install the belt filter press on a reinforced concrete foundation that has been poured and cured for 7 days in advance; the reinforced concrete foundation shall be 1.5 times the bottom area of ​​the belt filter press, with a thickness of not less than 30cm, and contain a steel mesh with a diameter of 12mm and a spacing of 20cm.

[0050] S16. Use a level to calibrate the flatness of the reinforced concrete foundation; the error should not exceed ±5mm. Install 5cm thick rubber shock-absorbing pads at the bottom of the belt filter press to prevent ground settlement or equipment displacement caused by operational vibration.

[0051] S17. Secure the belt filter press to the reinforced concrete foundation using anchor bolts with a diameter of not less than 16mm. Connect the 150mm diameter inlet pipe and the 100mm diameter drain pipe according to the belt filter press layout. Use flange connections for the pipes, equipped with rubber sealing rings, and tighten the connections to the torque value specified by the manufacturer.

[0052] S18. After completion, conduct a pipeline pressure test to ensure there is no leakage of mud or water.

[0053] After the belt filter press is installed, perform no-load and belt-load testing. First, perform no-load testing by starting the equipment and running it for 30 minutes to check the electrical system, transmission components and filter belt operation, ensuring that there is no abnormal noise or vibration and that the motor temperature rise is within the normal range.

[0054] Then, load testing was carried out, and sludge was gradually introduced. The initial flow rate was 50% of the design value. The filtration effect and the moisture content of the discharged sludge were observed.

[0055] During the commissioning process, a moisture content tester was used every 30 minutes to sample and test the sludge to ensure that the moisture content of the discharged sludge was stable at 40%-50%. Based on the test results, the sludge feed rate, filter belt speed and tension of the equipment were adjusted, and all parameters were recorded to ensure that the equipment could run continuously and stably at full load for more than 8 hours to meet the construction requirements.

[0056] In some embodiments, the specific implementation process of step S2, sludge dewatering, is as follows:

[0057] S21. Before the formal dewatering operation, conduct a comprehensive inspection of the mechanical and electrical components of the belt filter press. Control the filter belt tension at 15-20 N / mm; lubricate all transmission components; install a filter screen with an aperture of no more than 5 mm at the feed inlet to prevent impurities from entering; start the equipment, gradually open the mud inlet valve, and control the mud inlet pressure within the range of 0.1-0.3 MPa.

[0058] S22. Monitor filtrate clarity in real time and regularly sample and test suspended solids content to ensure compliant discharge. Adjust filter belt speed and compaction force according to sludge moisture content to maintain sludge moisture content between 40% and 50%. Record operating parameters and test data hourly to ensure stable and efficient dewatering process.

[0059] S23. After dehydration, the dehydrated mud cake is evenly spread in the dehydration zone via a conveyor belt, maintaining a thickness of 30-50cm. The ground of the dehydration zone has been reinforced with concrete or laid with an impermeable membrane, and a 2% drainage slope has been set to meet the drying requirements.

[0060] S24. After the mud cake is spread, check the moisture content of the silt every 2-3 hours. Use mechanical turning equipment to turn the mud cake in the dehydration zone to increase evaporation efficiency until the moisture content of the silt drops to 35%-40%, providing suitable mud conditions for subsequent construction. After spreading, record the weather conditions of the day. If the temperature is above 15℃ and the humidity is low, the weather conditions are conducive to moisture evaporation. In the case of high humidity or rainy weather, the drying time can be appropriately extended to 8-12 hours.

[0061] In some embodiments, the specific implementation process of step S3, sludge fermentation modification to obtain sludge compost planting soil, is as follows:

[0062] S33. Assess and clear the transportation route according to construction requirements. If necessary, lay steel plates or gravel roadbeds in soft road sections to improve the road's load-bearing capacity and prevent vehicles from getting stuck or damaging the road surface.

[0063] During transportation, loaders or enclosed transport vehicles with a load capacity not exceeding 80% of the equipment's rated capacity should be used, and the vehicle speed should be strictly controlled within 10 km / h to ensure transportation safety and avoid pollution caused by sudden braking or sharp turns.

[0064] S34. After the sludge is transported to the construction site, it shall be unloaded into the stockpiling area. The stockpiling area shall be located in a flat area with good drainage. The ground shall be covered with a geomembrane with a thickness of not less than 1.5 mm, and a 0.5 m high dike shall be set up around the perimeter to prevent leachate leakage.

[0065] S35. When unloading sludge, it should be piled up evenly, with the pile height controlled to not exceed 2m, and the distance between piles should be kept at 1m to facilitate ventilation and subsequent processing.

[0066] S36. A dedicated fermentation area shall be set up in the material stockpiling area for the mixing and fermentation of sludge compost and planting soil. The area of ​​the fermentation area shall be planned according to construction needs, and is usually set at 15-30m². 2 The fermentation area is covered with an impermeable membrane and a collection ditch is set up. The collection ditch is connected to a sedimentation tank or wastewater collection system to treat the leachate generated during the fermentation process.

[0067] S37. Within the fermentation area, add 3.0% well-rotted organic fertilizer, 1.1% superphosphate, and 0.7% potassium magnesium sulfate fertilizer per cubic meter of pond sludge. Mix evenly using a mechanical mixer or loader, then pile the mixture, ensuring the pile height does not exceed 2 meters and the top is rounded to facilitate drainage. After mixing, manage the fermentation process to ensure the formation of suitable sludge compost for planting.

[0068] S38. During fermentation, the compost pile should be turned over every 2-3 days to ensure good internal ventilation and promote uniform fermentation. Turning can be done using a turner or loader. Simultaneously, monitor the pile temperature and humidity, ensuring the temperature remains between 45-65℃ and the humidity is suitable to prevent clumping. Thermometers should be installed in the middle and top of the pile to record temperature changes regularly. Humidity can be adjusted as needed by spraying water or covering with breathable tarpaulins. In this embodiment, ventilated fermentation is used to ensure sufficient oxygen supply and promote the balanced degradation of organic matter.

[0069] S39. Spray biological deodorizers or cover the pile with breathable tarpaulins to reduce environmental impact. The pile must be left to ferment for at least 7 days to ensure full fermentation, ultimately forming a material with uniform structure, no odor, and suitable physical properties, which is silt compost planting soil;

[0070] After fermentation is complete, the fermentation effect of the material is checked to ensure that the pile is uniform in color, free of unrotted particles, and the moisture content is controlled at 30%-35%. The material should be loose and uniform in granular form and free of obvious odor. Before transfer, the batches of the pile and the fermentation time are classified and recorded to ensure traceability.

[0071] In some embodiments, the specific implementation process of step S4, slope planting soil construction, is as follows:

[0072] S41. Using the finished bacterial strain to prepare bacterial solutions, this embodiment uses Yiqiang Bio's 100 billion / g Bacillus subtilis strain and Shandong Top Bio's second-generation active ferrooxidizum bacteria cultured on culture medium. When preparing the Bacillus subtilis bacterial solution, accurately weigh 1.0g of highly active bacterial cells and add them to 49.0mL of distilled water or nutrient solution. Use a mechanical stirrer to stir thoroughly to ensure uniform distribution of the bacterial cells and form a uniform suspension to obtain a 2% concentration Bacillus subtilis bacterial solution, denoted as bacterial solution A. When preparing the ferrooxidizum bacteria solution, accurately weigh 6.3g of highly active ferrooxidizum bacteria and add them to 193.7g of distilled water or nutrient solution. Stir thoroughly to obtain a 4% concentration ferrooxidizum bacteria solution, denoted as bacterial solution B.

[0073] S42. After preparing bacterial solution A and bacterial solution B, mix bacterial solution A and bacterial solution B at a volume ratio of (2-3):(5-5.5) to obtain a composite bacterial solution; preferably, the spraying amount of undisturbed soil on the slope is: bacterial solution A 0.6-0.9 L / m³.2 Bacterial solution B is 1.5-1.65 L / m³. 2 The spraying rate of the compound bacterial solution is 2.1-2.55 L / m³. 2 ;

[0074] The compound bacterial solution was sprayed directly onto the undisturbed soil surface of the slope using a positive displacement pump at a pressure of 2.5 bar and a flow rate of 80 ml / min. The solution was sprayed evenly in sections, from top to bottom and from one side to the other. The spraying volume was precisely controlled using metering equipment to ensure uniform distribution of the compound bacterial solution. The spraying equipment was calibrated to ensure accurate spraying volume per square meter.

[0075] Before construction, confirm that the moisture content of the original soil on the slope is between 12% and 15%. If the moisture content is too low, use a water spraying device to spray an appropriate amount of clean water to adjust it to the design range. Choose a suitable construction time and avoid spraying under extreme weather conditions to ensure effective coverage and action of the bacterial solution.

[0076] S43. After the compound bacterial solution is sprayed, cover the slope area with plastic film to maintain suitable humidity, promote the growth and reproduction of the bacterial community, and prevent rainwater or excessive sunlight from directly affecting the sprayed bacterial solution, ensuring its stability in the soil.

[0077] S44. After covering, allow at least 48 hours for the original soil of the slope and the heavy metal degrading bacteria to fully solidify and establish themselves, thus forming a biological heavy metal isolation layer, before proceeding to the next stage of construction.

[0078] S45. Use a total station and GPS system to conduct detailed measurements of the slope and build templates. Use frame beam type wooden templates on the slope with a height of H meters, and divide the slope into several layers according to its verticality.

[0079] The unit grid is set according to the size of the slope and the terrain, such as 2m×2m, 2m×4m, 3m×2m, etc.; 20mm thick, 2m long, and 30cm deep wooden boards are used as the frame beam type wooden formwork material; the formwork is reserved with an allowance of about 1-2cm to ensure that the formwork fits tightly to the slope and remains stable during on-site installation by using wooden wedges or fine-tuning the support components; positioning piles are set every 5 meters in the horizontal direction, and a horizontal support beam is set every H / 3 of the slope height in the vertical direction. When installing the formwork piece by piece, adjacent pieces are fixed with steel nails, and the intersections of the grid are connected by bolts with a diameter of 12mm to enhance the overall rigidity; support rods are added every 2 meters vertically, and corner timbers are added to reinforce the corners and edges; after the installation is completed, a level is used to check the flatness and tilt of the formwork.

[0080] S46. At the construction site, pond sludge with a moisture content of 35% shall be uniformly mixed with 6.0% phosphogypsum, 7.5% fly ash, 5.0% manganese slag, and 8% cement according to the designed mix ratio per cubic meter of pond sludge. The moisture content of the pond sludge shall be controlled between 30% and 35%. The phosphogypsum shall be a powder with a particle diameter ≤5mm, and the fly ash and manganese slag shall be sieved beforehand with a particle diameter ≤3mm. PO 42.5 cement shall be used. The mixing operation shall be carried out using on-site mechanical mixing, with a mixing time of not less than 20 minutes, ensuring no material separation during the mixing process. The moisture content after mixing shall be controlled between 12% and 15%.

[0081] S47. Use a filler pump to evenly fill the installed template frame with the mixed skeleton material. The thickness of each filling layer should be controlled between 10-15cm to ensure uniform coverage and full bonding of the material. During the filling process, use a trowel or scraper to manually smooth the filling material to avoid forming voids or uneven areas.

[0082] S48. After completing the filling process, allow at least 24 hours for the filling material to cure and bond naturally. The specific curing time should be adjusted according to environmental conditions such as temperature and humidity. The cured strength should reach C25 level. Cover the filled area with plastic film to maintain humidity and prevent rain or excessive sunlight from directly affecting the curing process.

[0083] S49. After the filling material has initially cured, carefully remove the formwork frame, ensuring that the formed slope protection skeleton is not damaged. Use pliers, wrenches, or hammers to smoothly disassemble the steel or wooden formwork and remove it gradually, avoiding impact or damage to the skeleton. After removing the formwork, use a level to measure the surface flatness to ensure that it meets the design slope requirements (2% drainage slope).

[0084] S410. Mix the weighed grass seeds with silt compost and planting soil in a 1m... 3 Mix 1-2 kg of grass seeds evenly into the compost to obtain grass seed-compost material; use a mechanical mixer to mix at medium speed for 5-8 minutes to ensure that the grass seeds are evenly distributed in the silt compost planting soil.

[0085] S411. Select breathable geotextile bags with a specification of 80cm×50cm and a thickness of 0.5-0.8mm. When selecting geotextile bags, strictly use standard 80cm×50cm synthetic fiber geotextile bags, requiring a weave density of ≥60 threads / 10cm and a tensile strength of ≥10kN / m. Fill the bags with the mixed grass seed-compost material, controlling the filling weight of each bag to be 20-25kg. Use an electronic scale for calibration during bagging, with an error not exceeding ±5%.

[0086] S412. Fill the pre-built protective frame with layers of filled geotextile bags, ensuring each layer fits tightly with no gaps greater than 1cm between bags. When laying horizontally, maintain the flatness of the bag surface within ±10mm. The final surface elevation error after laying three layers of bagged material should be controlled within ±20mm.

[0087] S413. After completing the surface layer construction of the slope, excavate drainage ditches along the contour lines at the toe of the slope. The drainage ditches should be 30cm wide and 20cm deep, with a slope of not less than 1%. During the excavation of the drainage ditches, ensure the stability of the slope walls, the flatness of the bottom without water accumulation, and the smooth and unobstructed drainage function. The drainage ditches should be connected to the overall drainage system of the slope to ensure that rainwater or seepage can be discharged in a timely manner. After construction, use a slope gauge to check the slope at the bottom of the slope and the drainage effect to ensure that there is no reverse slope at the bottom of the slope and that the design drainage function requirements are met.

[0088] The embodiments of the present invention have the following advantages:

[0089] (1) Significantly Improved Overall Performance of Silt After Modification: A systematic and multi-layered modification method was adopted, adding specific modifying materials and functional microbial agents to different soil layers. During the isolation layer spraying process, Bacillus subtilis and Thiobacillus ferrooxidans microbial strains were precisely formulated and evenly sprayed onto the undisturbed soil surface of the slope. Strict control was exercised over the concentration of the bacterial solution, the spraying amount, and the soil moisture content, enabling more efficient biodegradation and fixation of heavy metals. The slope protection framework incorporated solid waste materials such as phosphogypsum, fly ash, and manganese slag, along with cement, and strictly controlled the moisture content, effectively enhancing soil strength and erosion resistance. The slope surface layer was constructed by piling silt compost and planting soil, along with grass seeds, into geotextile bags, providing a uniform, well-aerated, and nutrient-rich growth medium for vegetation growth, achieving comprehensive optimization of silt strength, environmental safety, and vegetation adaptability. Overall, this invention achieves enhanced soil strength, improved environmental safety, and comprehensive optimization of vegetation adaptability, providing a green and safe protection approach for slope engineering.

[0090] (2) Improving construction efficiency and standardization: A systematic operation plan covering the entire process from sludge dewatering and modification to layered construction was proposed. Through scientific site selection of the dewatering zone, optimization of the drainage system, and the use of high-efficiency belt filter presses and mechanical turning technology, the sludge moisture content was rapidly reduced to 35%-40%. During construction, the fermentation area was rationally planned, and mechanized mixing and turning methods were adopted, improving the fermentation efficiency and uniformity of the modified materials. On-site construction involved layered slope operations, strictly following the steps of spraying bacterial solution onto the isolation layer, constructing the slope protection framework with solid waste mixture, and filling the framework with bags of compost and grass seed mixture. The standardized construction process not only improved efficiency but also ensured the controllability and consistency of construction quality, avoiding random errors caused by manual operation.

[0091] (3) Enhancing slope stability and safety: A slope protection framework is constructed using frame beam-type wooden formwork, establishing a stable slope protection framework structure that can accurately correct flatness and inclination. The uniform spraying of compound bacterial solution, the layered filling of modified materials, and the bagging and filling of compost are all carried out in an orderly manner within this slope protection framework, which improves the density, uniformity, and overall stability of the slope, and reduces the risk of landslides, settlement, and erosion.

[0092] (4) Effective utilization of solid waste resources and promotion of green construction: The introduction of solid wastes such as phosphogypsum, fly ash, and manganese slag into the stabilization layer realizes the resource utilization of solid waste and reduces the cost of engineering materials. At the same time, during the fermentation process of the silt composting and planting soil, the odor pollution to the surrounding environment was reduced by turning, ventilation, and temperature and humidity monitoring. The construction area adopts the design of impermeable membranes and cofferdams to avoid leachate pollution of the surrounding soil and water bodies, providing an effective guarantee for green construction.

[0093] The following experimental examples illustrate the material design of the isolation layer, stabilization layer, and slope surface layer in this invention.

[0094] In Experiments 1-3, setting up weakly acidic, neutral, and weakly alkaline pH gradients and measuring the final pH to obtain pH change conclusions can provide theoretical basis and guidance for different application scenarios. In actual construction, there is no need to specifically adjust the pH.

[0095] Experimental Example 1

[0096] Experiment 1 aims to evaluate the effects of different bacterial strain ratios, undisturbed soil moisture content, and pH value on the heavy metal content of the isolation layer raw materials.

[0097] Experimental Design: An orthogonal experimental design was adopted, with a blank control group (CK1). The experimental design is shown in Table 1. The thickness of the undisturbed soil on the slope mixed with the bacterial strain was set to 30 cm. The undisturbed soil in the blank control group (CK1) had a moisture content of 12.5%, a pH of 7.0, and did not contain Bacillus subtilis or Thiobacillus ferrooxidans.

[0098] Table 1 Orthogonal experimental design of isolation layer materials

[0099] <![CDATA[Bacillus subtilis (g / m 3 )]]> 40 50 60 <![CDATA[Acidithiobacillus ferrooxidans (g / m 3 )]]> 180 200 220 Moisture content of undisturbed soil on the slope (%) 10 12.5 15 pH value 6.5 7.0 7.5

[0100] Experimental steps:

[0101] (1) Sample preparation: Cultivate the bacterial strain to ensure that the activity and concentration meet the experimental requirements. Collect undisturbed soil from the same source and sieve it to less than 2 mm; adjust the moisture content of the undisturbed soil according to the experimental design.

[0102] According to the experimental design, hydrochloric acid and sodium hydroxide solutions were used to adjust the pH value of the undisturbed soil on the slope.

[0103] (2) Sample mixing: Add Bacillus subtilis and ferrous thiobacillus according to the experimental design, stir at low speed to mix evenly, and control the mixing time to 10 minutes to avoid excessive stirring that could damage the soil structure.

[0104] (3) Fermentation treatment: The mixed sample was placed in a sealed container and fermented in a fermentation chamber for 7 days under the optimal conditions for the strain. The purpose of short-term fermentation treatment of the sample in this experiment is to enable it to reach a relatively stable survival state in a short period of time, so as to ensure the stability of the experiment.

[0105] (4) Sample testing: Use a heavy metal analyzer (such as an atomic absorption spectrometer) to determine the content of lead (Pb), cadmium (Cd), and mercury (Hg) in the sample; perform sample pretreatment in accordance with national or industry standards.

[0106] The final pH value of the sample was determined using a calibrated pH meter. The purpose of measuring the pH value was to obtain the pH difference before and after the experiment. If the pH value remained within a stable range, it indicates that the experimental group had good stability.

[0107] Experimental results: The experimental results are shown in Table 2.

[0108] Table 2. Results of orthogonal experiments on the materials for the isolation layer.

[0109]

[0110] Table 2 shows that as the amount of Bacillus subtilis and Thiobacillus ferrooxidans added increased, the Pb content generally decreased, but the Pb content was higher at high water content and low pH. Adding bacterial strains and a suitable pH helped reduce the Cd content. Adding bacterial strains and a suitable pH reduced the Hg content, but high water content may lead to increased Hg release. Experimental group 15 had the lowest Pb, Cd, and Hg contents, while experimental group 6 had the highest Pb, Cd, and Hg contents.

[0111] The pH range of the experimental group was 6.4-7.6, while the pH of the control group was 7.0. Some experimental groups achieved pH increase by adding bacterial strains and adjusting pH, but the effect was not good under extreme conditions (high water content and low pH).

[0112] Considering both heavy metal content and final pH value, the optimal formulation was experimental group 14. This is because the optimal growth pH for *Bacillus subtilis* and *Thiobacillus ferrooxidans* is concentrated in the slightly acidic-neutral range of 6.5-7.0, while the final pH of experimental group 15 was 7.6, which was unfavorable for the growth of *Bacillus subtilis* and *Thiobacillus ferrooxidans*. Experimental group 14 contained 50 g / m³ of *Bacillus subtilis*. 3 200g / m³ of *Thiobacillus ferrooxidans* 3The original soil moisture content was 12.5%, the original soil pH value was 7.0, and the final pH value was 7.2. Its effect on reducing heavy metals was slightly less than that of the experimental group 15, but its final pH value was able to remain relatively stable.

[0113] Converting the optimal bacterial strain dosage in experimental group 14, the dosage of Bacillus subtilis in the undisturbed soil of the slope is 50 g / m². 3 ×0.3m ÷ 2% = 750mL / m 2 The dosage of *Thiobacillus ferrooxidans* in the undisturbed soil of the slope is 200 g / m². 3 ×0.3m ÷ 4% = 1500mL / m 2 .

[0114] Experiment Example 2

[0115] Experimental Example 2 aims to evaluate the effects of different proportions of phosphogypsum, fly ash, manganese slag, cement, and pH value on the unconfined compressive strength and internal friction angle of the stabilized layer.

[0116] Experimental Design: An orthogonal experimental design was adopted. The experimental design is shown in Table 3.

[0117] Table 3 Orthogonal experimental design of stabilized layer materials

[0118] phosphogypsum addition amount (%) 5.0 6.0 7.0 Fly ash addition amount (%) 6.0 7.5 9.0 Manganese slag addition amount (%) 4.0 5.0 6.0 Cement addition amount (%) 8.0 9.0 10.0 pH value 7.0 7.5 8.0

[0119] Experimental steps:

[0120] (1) Sample preparation: According to the experimental design, accurately weigh each additive; adjust the pH value of the raw material mixture with hydrochloric acid and sodium hydroxide solution.

[0121] The silt has a water content of 35%, and pond silt with fewer impurities is selected without sieving. The pond silt is mixed with the weighed additives according to the design ratio. The mixture is stirred at medium speed for 15 minutes to ensure that the additives are evenly distributed in the silt.

[0122] (2) Sample preparation: The mixed stabilizing layer material is placed into a standard mold and cured for a certain period of time (e.g., 7 days) before testing. The test conditions shall be performed in accordance with relevant standards (e.g., ASTM D4440).

[0123] (3) Sample testing: The unconfined compressive strength of the sample was determined using a compression testing machine. The internal friction angle of the sample was determined using a shear testing machine or the direct shear method.

[0124] Experimental results: The experimental results are shown in Table 4.

[0125] Table 4 Results of the orthogonal experiment on stable feedstock

[0126]

[0127]

[0128] Table 4 shows that the unconfined compressive strength gradually increases with the appropriate increase of phosphogypsum and fly ash (experimental groups 11-15, 22-24, etc.). However, when the amount of phosphogypsum added increases from 6.0% to 7.0% (experimental groups 20-24), the increase in unconfined compressive strength gradually decreases and even tends to stabilize, indicating that the optimal addition amount of phosphogypsum may be close to 6.0%. The increase in compressive strength is more significant at 7.5% fly ash (compared to experimental groups 10, 11, and 12 in experimental groups 13, 14, and 15), while excessively high (9%) amounts may produce a saturation effect (Nos. 16-18).

[0129] The internal friction angle reached a relatively high level when the manganese slag content was 5.0% and the pH value was 7.5-8.0 (as seen in experimental groups 14, 15, and 17). Excessively high manganese slag proportions (experimental groups 25-27) did not significantly increase the internal friction angle. Cement at 8.0% (experimental groups 14 and 20), as a basic cementitious material, effectively improved the internal friction angle through its stabilizing effect, but the effect weakened after further increasing to 10% (experimental groups 25, 26, and 27).

[0130] Taking into account unconfined compressive strength, internal friction angle, pH value, and economy, the optimal mix proportion is 6.0% phosphogypsum, 7.5% fly ash, 5.0% manganese slag, and 8.0% cement.

[0131] Experimental Example 3

[0132] Experiment 3 aims to evaluate the effects of different proportions and paving thicknesses of the surface layer materials on heavy metal content and plant growth.

[0133] Experimental Design: An orthogonal experimental design was adopted, with a blank control group (CK3). The experimental design is shown in Table 5. The blank control group (CK3) had a sludge moisture content of 35%, a pH value of 2 (the original pH value of the sludge), a spreading thickness of 30 cm, and no added well-rotted organic fertilizer, superphosphate, or potassium magnesium sulfate fertilizer.

[0134] Table 5 Orthogonal experimental design of materials for slope surface layer

[0135] Amount of well-rotted organic fertilizer added (%) 2.5 3.0 3.5 Superphosphate addition amount (%) 1.0 1.1 1.2 Potassium magnesium sulfate fertilizer addition rate (%) 0.5 0.7 0.9 Paving thickness (cm) 25 30 35

[0136] Experimental steps:

[0137] (1) Sample preparation: According to the experimental design, accurately weigh each additive; adjust the pH value of the raw material mixture with hydrochloric acid and sodium hydroxide solution. The silt has a water content of 35%. Mix the pond silt with the weighed additives according to the designed ratio; use a mixer to stir at medium speed for 15 minutes to ensure that the additives are evenly distributed in the silt.

[0138] (2) Fermentation treatment:

[0139] Sample loading: Load the mixed slope surface layer material into containers in the fermentation chamber, ensuring the containers are well sealed to prevent external contamination.

[0140] Control fermentation conditions: Set the temperature between 45-65℃, adjusting according to the properties of the fertilizer and sludge. Maintain humidity within a suitable range, avoiding both excessive dryness and excessive moisture.

[0141] Fermentation cycle: 7 days. Temperature and humidity are monitored and recorded daily during this period. If the temperature or humidity deviates from the set range, the fermentation chamber conditions are adjusted promptly.

[0142] In this experimental example, the purpose of using sealed fermentation treatment is to precisely control the oxygen concentration and humidity in the experimental environment, ensure that the experimental conditions are accurate and controllable, and thus analyze the differences in the effects of variables such as admixtures and organic fertilizers on the performance of the soil covering.

[0143] (3) Sample spreading and vegetation planting:

[0144] The fermented slope surface layer material was spread evenly in the test apparatus to the designed thickness, maintaining a 2% drainage slope. The test apparatus included a slope constructed to simulate the actual construction environment. Using manual planting methods, holes were dug at 20cm intervals and 3-5cm depths. Bermuda grass and ryegrass seeds were planted, covered with soil, and gently compacted. Water celery was planted at the foot of the slope at 30cm intervals and 5-10cm depth. After planting, a fine mist sprayer was used to evenly water the soil, keeping it moist to field capacity; if necessary, straw or non-woven fabric was used to cover the soil to prevent soil erosion. Plant height and growth were measured weekly, and the health of the vegetation was observed, with timely replanting and pest and disease control.

[0145] (4) Sample Testing: Soil samples were randomly collected from each experimental group, and the contents of lead (Pb), cadmium (Cd), and mercury (Hg) in the samples were determined using a heavy metal analyzer (such as an atomic absorption spectrometer). The final pH value of the samples was determined using a calibrated pH meter. On the 14th day after sowing, the rootstock height and growth were recorded. When measuring the rootstock height, 5 healthy plants were randomly selected from each experimental group as the measurement sample; first, the small lateral roots, leaves, and adhering soil were removed, and the main root and coarse secondary roots were retained. The length from the base of the rootstock to the tip of the main root was measured using vernier calipers, and the average value was calculated to obtain the rootstock height; then the plants were weighed, and the average value was calculated to obtain the growth.

[0146] Experimental results: The experimental results are shown in Table 6.

[0147] Table 6 Results of the orthogonal experiment on stable feedstock

[0148]

[0149] As can be seen from the experimental results in Table 6:

[0150] ① The plant height range is 12cm-25cm. Adding well-rotted organic fertilizer and appropriate fertilizers (superphosphate, potassium magnesium sulfate fertilizer) will significantly increase the plant height; the effect is best when the spread thickness is 30cm. Too low (6.5) or too high (8.0) pH value has a negative impact on plant growth.

[0151] The plant growth ranges from 18g to 30g. Appropriate fertilizer ratios and neutral pH values, similar to plant height, promote increased growth. The growth is highest when the mulch thickness is 30cm.

[0152] ② The lead (Pb) content ranges from 100mg / kg to 160mg / kg. Adding organic fertilizer and appropriate fertilizer can effectively reduce the Pb content, and increasing the paving thickness helps to further reduce it.

[0153] The cadmium (Cd) content ranges from 3.1 mg / kg to 4.5 mg / kg. Appropriate fertilizer ratio and neutral pH value help reduce Cd content. A spreading thickness of 30 cm is more effective.

[0154] The mercury (Hg) content ranges from 1.2 mg / kg to 2.3 mg / kg. Adding organic fertilizer and appropriate fertilizer can reduce the Hg content. The best effect is achieved when the paving thickness is 30 cm.

[0155] ③ The pH range of the experimental group was 6.4-7.8, and the pH of the control group was 7.0. The neutral pH (7.0) group performed the best, while extreme pH values ​​(6.5, 7.5, 8.0) had different effects on some properties.

[0156] ④ Taking into account plant height, growth, soil heavy metal content and pH value, the optimal ratio is 3.0% decomposed organic fertilizer, 1.1% superphosphate, 0.7% potassium magnesium sulfate fertilizer, spread thickness of 30cm, and pH value of 7.0. The optimal ratio is obtained by comprehensive analysis of the data from experimental groups 14, 16 and 20.

[0157] Experimental Examples 1-3 of this invention, through systematic orthogonal experimental design and implementation, compared key factors including heavy metal content, pH value, unconfined compressive strength, internal friction angle, plant height, and growth rate; verifying the optimal ratio of the three-layer structure of the planting soil.

[0158] In the isolation layer, the moisture content of the original soil on the slope is 12.5%. In the compound bacterial solution sprayed per square meter of original soil on the slope, the amount of bacterial solution A is 0.75L and the amount of bacterial solution B is 1.5L.

[0159] In the slope protection framework, the percentages of each component by mass of the silt are as follows: phosphogypsum 6.0%, fly ash 7.5%, manganese slag 5.0%, and cement 8%.

[0160] The percentages of each component in the surface layer of the slope silt by mass are as follows: 3.0% decomposed organic fertilizer, 1.1% superphosphate, 0.7% potassium magnesium sulfate fertilizer, and a spreading thickness of 30cm.

[0161] The above description is merely 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 shall be within the scope of protection of the pending claims of the present invention.

Claims

1. A construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials, characterized in that, Includes the following steps: Laying the isolation layer: A compound bacterial solution containing heavy metal-degrading bacteria is directly sprayed onto the undisturbed soil surface of the slope. The bacterial solution infiltrates the slope soil to form a biological heavy metal isolation layer. The heavy metal-degrading bacteria include Bacillus subtilis and Acidobacterium ferrooxidans. The compound bacterial solution is prepared by separately preparing a 2% concentration of Bacillus subtilis bacterial solution and a 4% concentration of Acidobacterium ferrooxidans bacterial solution, and then mixing them at a volume ratio of (2-3):(5-5.5) to obtain the compound bacterial solution. The amount of compound bacterial solution sprayed onto the undisturbed slope soil is 2.1-2.55 L / m². 2 ; Slope protection framework casting: Silt, phosphogypsum, fly ash, manganese slag, and cement are mixed evenly in proportion and then cast into shape using a template on the isolation layer, solidifying to form the slope protection framework; phosphogypsum, fly ash, manganese slag, and cement account for 5%-7%, 6%-9%, 4-6%, and 8-10% of the silt mass, respectively; Slope surface layer construction: Silt composting soil and grass seeds are filled into geotextile bags and manually piled into the slope protection frame. The silt composting soil is made by fermenting silt with decomposed organic fertilizer, superphosphate and potassium magnesium sulfate fertilizer.

2. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: Silt, phosphogypsum, fly ash, manganese slag and cement are mixed at the on-site mixing plant for no less than 20 minutes. After being mixed evenly, the mixture is poured using a frame beam-type wooden formwork to form a slope protection skeleton. Among them, the phosphogypsum particles are powdery with a diameter ≤5mm, and the fly ash and manganese slag particles have a diameter ≤3mm.

3. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: The silt compost planting soil is made by mixing silt with 2.5%-3.5% of well-rotted organic fertilizer, 1%-1.2% of superphosphate and 0.5%-0.9% of potassium magnesium sulfate fertilizer by mass and then composting and fermenting it.

4. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: In the isolation layer, the moisture content of the original soil on the slope is controlled to 12%-15%.

5. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: In the slope protection framework and surface layer of the slope, pond silt is used; before mixing, the silt moisture content is reduced to 40%-50% using a filter press, and then the dewatered silt cake is spread in the dewatering zone for drying until the silt moisture content drops to 35%-40%; the daily processing capacity of the filter press is not less than 25m³. 3 The straight-line distance from the dehydration zone to the source of the silt shall not exceed 50m.

6. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: When composting silt for planting, the height of the pile should not exceed 2m, and the top of the pile should be rounded. During the fermentation process, the pile should be turned over every 2-3 days to ensure that the temperature of the pile is maintained within the range of 45℃-65℃. The pile should be left to ferment for no less than 7 days to ensure full fermentation, and finally form a uniform, odorless, and loose granular structure.

7. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: Ensure the compound bacterial solution spraying equipment is calibrated to guarantee accurate spraying volume per square meter; after spraying and curing, use a total station and GPS system to conduct detailed measurements of the slope and construct a frame beam-type wooden formwork for the slope; record the slope height as H meters. When constructing the frame beam-type wooden formwork, set positioning stakes every 5 meters in the horizontal direction, and set a horizontal support beam every H / 3 of the slope height in the vertical direction. Add a vertical support rod every 2 meters, and reinforce the corners and edges with corner timber.

8. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: After the surface layer of the slope is constructed, a drainage ditch is set up along the contour line at the toe of the slope, and seepage pipes are installed as needed to ensure drainage function; the length of the toe of the slope is 2-4m; the width of the drainage ditch is 25-35cm, the depth is 15-25cm, and the slope is not less than 1%.

9. The construction method for improving silt soil into a vegetable slope structure using microorganisms and solid waste materials according to claim 1, characterized in that: In the isolation layer, the original soil moisture content of the slope is 12.5%. 0.75L of 2% Bacillus subtilis bacterial solution and 1.5L of 4% Thiobacillus ferrooxidans bacterial solution are sprayed per square meter of original soil. In the slope protection framework, the percentage of each component by mass of silt is as follows: phosphogypsum 6.0%, fly ash 7.5%, manganese slag 5.0%, and cement 8%. In the surface layer of the slope, the percentages of each component by mass of the silt are as follows: well-rotted organic fertilizer 3.0%, superphosphate 1.1%, potassium magnesium sulfate fertilizer 0.7%, and the spreading thickness is 30cm.

10. A vegetationable slope structure that utilizes microorganisms and solid waste materials to improve silt soil, characterized in that: The method for constructing a vegetationable slope structure using microorganisms and solid waste materials to improve silt soil as described in any one of claims 1 to 9 includes: The isolation layer is formed by spraying a compound bacterial solution onto the original soil of the slope, and solidifying the solution after the bacteria in the solution have fully infiltrated the soil. The compound bacterial solution contains Bacillus subtilis and Thiobacillus ferrooxidans. The slope protection frame is set on the isolation layer and is constructed using a frame beam type wooden formwork. The raw materials of the slope protection frame include silt and 5%-7% phosphogypsum, 6%-9% fly ash, 4-6% manganese slag and 8-10% cement by weight of silt. The slope surface layer is composed of geotextile bags filled with silt compost planting soil and grass seeds. These geotextile bags are filled in layers into the pre-built slope protection frame, with 2-3 layers laid as needed. The silt compost planting soil contains the following components by mass percentage: 2.5%-3.5% well-rotted organic fertilizer, 1%-1.2% superphosphate, and 0.5%-0.9% potassium magnesium sulfate fertilizer.

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