Shotcrete and method for its production

Abstract

The application discloses a spray protection slurry and a preparation method thereof. The spray protection slurry comprises 15-20 parts of lignin, 15-20 parts of wood fiber, 2.5-3 parts of grass seeds, 2-15 parts of organic fertilizer 1, 1-1.7 parts of water-retaining agent, 15-25 parts of calcium chloride, 5-10 parts of cross-linking agent, 6-9 parts of phosphate fertilizer and 63-80 parts of water in terms of mass. Thus, the spray protection slurry is chemically consolidated with the soil in the form of forming calcium carbonate crystals by consuming potassium carbonate in the ash layer; and the spray protection slurry is physically consolidated with the soil by the cross-linking agent, the water-retaining agent, the wood fiber and the lignin. The spray protection slurry is sprayed on the surface of a fire-burned land, thereby stabilizing loose sources in the surface shallow layer of the fire-burned land and reducing mud-rock flow caused by surface runoff erosion in the early stage of the fire-burned land after rainfall. In addition, the solidified and consolidated soil layer contains mineral elements, organic fertilizer and suitable pH value, which are necessary for plant growth, and thus provides a suitable growth environment for the grass seeds, and is suitable for management of a medium-low risk fire-burned land.

Description

Technical Field

[0001] This application relates to the field of post-fire debris flow management and ecological restoration technology, specifically to sprayed slurry and its preparation method. Background Technology

[0002] Post-fire debris flows originate from large and exceptionally large forest fires. After a fire, a large layer of ash is created on the hillside. When this ash layer is combined with concentrated rainfall, it forms ash flows, becoming the primary source of material for the first debris flow in the burned area. Secondly, because the vegetation is destroyed by fire, its ability to consolidate the soil is greatly weakened. In addition, the fire bakes the topsoil, destroying its structure and causing moisture loss, making it increasingly loose and directly contributing to secondary debris flows. Therefore, treating loose debris and restoring vegetation as quickly as possible are key to managing this disaster.

[0003] It should be noted that the above statements are only used to provide background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0004] In a first aspect, this application proposes a sprayable slurry comprising: 15-20 parts lignin, 15-20 parts wood fiber, 2.5-3 parts grass seed, 2-15 parts organic fertilizer, 1-1.7 parts water-retaining agent, 15-25 parts calcium chloride, 5-10 parts crosslinking agent, 6-9 parts phosphate fertilizer, and 63-80 parts water. Thus, this sprayable slurry chemically consolidates the soil by consuming potassium carbonate, the main component of the ash layer, to form calcium carbonate crystals; and physically binds the soil through the crosslinking agent, water-retaining agent, wood fiber, and lignin. Spraying it onto the surface of burned areas stabilizes the loose material in the shallow layer of the soil, reducing the risk of mudslides caused by surface runoff from rainfall in the early stages after a fire. In addition, the solidified soil layer contains essential minerals, organic fertilizers, and a suitable pH value, providing a suitable growing environment for grass species and reducing the risk of shallow landslides triggered by rainfall infiltration in the later stages of a fire. It is suitable for the treatment of low- to medium-risk burned areas.

[0005] In addition, the sprayed protective slurry according to the above embodiments of this application may also have the following additional technical features:

[0006] In some embodiments of this application, the pH of the sprayed slurry is 6-6.7. This provides a favorable growing environment for seed development and plant growth.

[0007] In some embodiments of this application, the water content of the sprayed slurry is 38%-47%. This allows the sprayed slurry to have a suitable viscosity, maintaining good fluidity and slope adhesion.

[0008] In some embodiments of this application, the viscosity of the sprayed slurry is 2500 mPa·s-4500 mPa·s. This helps to maintain smooth spraying and stable adhesion to the slope.

[0009] In some embodiments of this application, the phosphate fertilizer comprises calcium dihydrogen phosphate. This provides calcium ions that react with the wood ash in the ash layer, while its weak acidity neutralizes the alkalinity of the wood ash, thus providing a favorable growing environment for grass seed development and plant growth.

[0010] In some embodiments of this application, the water-retaining agent includes sodium polyacrylate. This improves soil water retention and promotes plant growth.

[0011] In some embodiments of this application, the wood fiber comprises coniferous wood pulp fiber. This is beneficial for the physical bonding of soil.

[0012] In some embodiments of this application, the length of the wood fibers is 0.5 mm to 2 mm. This is beneficial for improving the bonding ability of the sprayed slurry.

[0013] In some embodiments of this application, the aspect ratio of the wood fibers is greater than or equal to 50:1. This is beneficial for improving the bonding ability of the sprayed slurry.

[0014] In some embodiments of this application, the crosslinking agent comprises polyvinyl alcohol and sodium carboxymethyl cellulose, wherein the mass ratio of polyvinyl alcohol to sodium carboxymethyl cellulose is 1:(2-3). This facilitates physical bonding of the soil.

[0015] In some embodiments of this application, the organic fertilizer includes poultry and livestock manure compost, straw carbonization, and edible mushroom residue, wherein the mass ratio of the poultry and livestock manure compost, the straw carbonization, and the edible mushroom residue is (3-2.5):(2-1.5):1. This allows for the resource utilization of waste and provides nutrients for grass seed growth.

[0016] In a second aspect of this application, a method for preparing a sprayed protective slurry is provided, comprising:

[0017] The water-retaining agent, the crosslinking agent, the calcium chloride, the lignin, the wood fiber, the organic fertilizer, and the first portion of water are mixed to form a first solution;

[0018] Add a second part of water to the first solution to form a second solution, the viscosity of which is 2500 mPa·s-4500 mPa·s;

[0019] The phosphate fertilizer was added to the second solution to obtain an initial slurry with a pH of 6-6.7;

[0020] The grass seeds are added to the initial slurry to obtain the sprayed slurry.

[0021] This application prepares a sprayed protective slurry using the above method. This sprayed protective slurry makes full use of the wood ash produced by fire, turning the disaster source into fertilizer and solidifying agent. It solves the problem of time-consuming and labor-intensive clearing and blocking of material sources in the past, and meets the fundamental need for rapid treatment of fire-affected areas and reduction of mudslides after rainfall.

[0022] In some embodiments of this application, during the formation of the second solution, the second portion of water is added at a rate of 0.5 L / min to 1 L / min. This facilitates obtaining a second solution with a suitable viscosity.

[0023] In some embodiments of this application, the second solution is formed by stirring at a speed of 200 rpm to 300 rpm. This allows the second solution to be mixed more evenly.

[0024] In some embodiments of this application, the mass ratio of the first part of water to the second part of water is (8-10):1. This is beneficial for controlling the viscosity of the sprayed slurry. Detailed Implementation

[0025] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0026] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are open-ended expressions, meaning they include what is specified in this application but do not exclude other aspects.

[0027] In the description of this application, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by one of the art, such as 1%, 2%, 3%, 4%, or 5%.

[0028] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0029] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0030] In this application, the order in which the steps are written does not imply a strict execution order and does not limit the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps in this application can be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0031] Current emergency measures for fire-affected areas include slope clearing, dam construction, and sedimentation basins to clear and intercept debris, supplemented by drone seeding. However, wood ash, the main component of the ash layer, contains various essential mineral nutrients for plant growth, primarily potassium. Simply treating it as debris flow source cleanup is extremely time-consuming and labor-intensive, and can lead to nutrient loss, hindering vegetation restoration. Furthermore, drone seeding results in low seed survival rates. Therefore, methods for post-fire debris flow management and vegetation restoration in fire-affected areas require further improvement.

[0032] In a first aspect, this application proposes a spray slurry comprising: 15-20 parts lignin, 15-20 parts wood fiber, 2.5-3 parts grass seed, 2-15 parts organic fertilizer, 1-1.7 parts water-retaining agent, 15-25 parts calcium chloride, 5-10 parts crosslinking agent, 6-9 parts phosphate fertilizer, and 63-80 parts water. This spray slurry chemically consolidates the soil by consuming potassium carbonate, the main component of the ash layer, through calcium chloride to form calcium carbonate crystals; it also physically binds the soil through the crosslinking agent, wood fiber, and lignin. Furthermore, the weak acidity of the phosphate fertilizer neutralizes the alkalinity of the wood ash, providing a favorable growing environment for seed development and plant growth; water regulates the viscosity of the spray slurry to maintain good fluidity and slope adhesion; the organic fertilizer provides nutrients for grass seed growth; and the water-retaining agent enhances the soil's water retention capacity. Therefore, spraying the slurry onto the surface of the burned area can stabilize the loose material in the shallow layer of the ground, reducing the mudslides caused by surface runoff due to rainfall in the early stage after the burned area is burned. In addition, the solidified soil layer contains the mineral elements, organic fertilizer and suitable pH value necessary for grass growth, which provides a suitable growth environment for grass and reduces the shallow surface landslides triggered by rainfall infiltration in the later stage of the burned area. It is suitable for the treatment of low- to medium-risk burned areas.

[0033] In addition, the sprayed protective slurry according to the above embodiments of this application may also have the following additional technical features:

[0034] In some embodiments of this application, the pH of the spray slurry is 6-6.7, for example, it can be 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, or 6.7. It is understood that the phosphate fertilizer (such as calcium dihydrogen phosphate) in the spray slurry is weakly acidic, which can adjust and neutralize the alkalinity of the wood ash, thereby providing a favorable growing environment for seed development and plant growth.

[0035] In some embodiments of this application, the water content of the sprayed slurry is 38%-47%, for example, it can be 38%, 40%, 42%, 44%, 46%, or 47%. This allows the sprayed slurry to have a suitable viscosity, maintaining good flowability and slope adhesion.

[0036] In some embodiments of this application, the viscosity of the sprayed slurry is 2500 mPa·s-4500 mPa·s, for example, it can be 2500 mPa·s, 3000 mPa·s, 3500 mPa·s, 4000 mPa·s, or 4500 mPa·s. This helps to maintain smooth spraying and stable adhesion to the slope.

[0037] In some embodiments of this application, the phosphate fertilizer includes calcium dihydrogen phosphate (Ca(H2PO4)2). This provides calcium ions that react with the wood ash in the ash layer, while its weak acidity neutralizes the alkalinity of the wood ash, thus providing a favorable growing environment for grass seed development and plant growth.

[0038] In this application, the basic curing principle of the sprayed protective slurry is: Ca 2+ +CO3 2- →CaCO3↓, calcium ions (Ca) in the reaction 2+ The solution is replenished by CaCl2 and Ca(H2PO4)2 in the sprayed slurry; while carbonate ions (CO3) are replenished. 2- The calcium ions are provided by the wood ash (K2CO3) in the ash layer at the site. In addition, Ca(H2PO4)2 not only provides calcium ions, but it is also a phosphate fertilizer. It is easily soluble in water, and its weak acidity can adjust and neutralize the alkalinity of the wood ash, or provide a good growing environment for grass seed development and plant growth according to the pH value required by the grass seed itself.

[0039] In some embodiments of this application, the water-retaining agent includes sodium polyacrylate. This improves soil water retention and promotes plant growth.

[0040] In some embodiments of this application, the wood fiber includes coniferous wood pulp fiber, such as pine pulp fiber or fir pulp fiber. Therefore, it can be used for physically cementing soil.

[0041] In some embodiments of this application, the length of the wood fibers is 0.5mm-2mm, for example, 0.5mm, 1mm, 1.5mm, or 2mm. Wood fibers within this length range can form a dense filling structure and construct a through-type skeleton, thereby improving the bonding ability of the sprayed slurry.

[0042] In some embodiments of this application, the aspect ratio of the wood fibers is greater than or equal to 50:1, for example, it can be 50:1, 52:1, 54:1, 56:1, 58:1, or 60:1. Here, the aspect ratio of the wood fibers refers to the ratio of the length to the diameter of the wood fibers. A larger aspect ratio is beneficial to the rheological properties of the sprayed slurry and ensures that the wood fibers break before the interface debonds. An aspect ratio of the wood fibers within the above range is beneficial to improving the bonding ability of the sprayed slurry.

[0043] In some embodiments of this application, the crosslinking agent includes polyvinyl alcohol (PVA) and sodium carboxymethyl cellulose (CMC), with a mass ratio of PVA to CMC of 1:(2-3), such as 1:2, 1:2.5, or 1:3. The crosslinking agent can achieve a balanced crosslinking of hydrogen bonds and ionic bonds, thereby facilitating the physical bonding of soil.

[0044] In some embodiments of this application, the organic fertilizer includes poultry and livestock manure compost, straw carbonization, and edible mushroom residue, with a mass ratio of (3-2.5):(2-1.5):1, such as 3:2:1, 3:1.5:1, 2.5:2:1, or 2.5:1.5:1. This allows for the resource utilization of waste, providing nutrients for grass growth.

[0045] In a second aspect of this application, a method for preparing a sprayed protective slurry is provided, comprising:

[0046] S1: Mix the water-retaining agent, cross-linking agent, calcium chloride, lignin, wood fiber, organic fertilizer and the first portion of water to form the first solution.

[0047] In this step, the order in which the raw materials are added is not specifically limited, and those skilled in the art can add them flexibly according to actual needs. Specifically, the water-retaining agent, cross-linking agent, and water can be thoroughly stirred to form a solution first, and then calcium chloride, lignin, wood fiber, and organic fertilizer can be added in sequence and stirred thoroughly again.

[0048] S2: Add a second part of water to the first solution to form a second solution with a viscosity of 2500 mPa·s-4500 mPa·s.

[0049] In this application, the spraying slurry is prepared through a stepwise mixing process. Adding the first part of water helps to form a solution, while adding the second part of water adjusts the viscosity of the spraying slurry to a suitable level, thereby maintaining smooth spraying and stable adhesion to the slope. It should be noted that after adding phosphate fertilizer and grass seeds to the second solution, the viscosity of the second solution remains unchanged; therefore, the viscosity of the second solution is the same as the viscosity of the spraying slurry.

[0050] In some embodiments of this application, during the formation of the second solution, the rate at which the second portion of water is added is 0.5 L / min to 1 L / min, for example, 0.5 L / min, 0.6 L / min, 0.7 L / min, 0.8 L / min, 0.9 L / min, or 1 L / min. This facilitates obtaining a second solution with a suitable viscosity.

[0051] In some embodiments of this application, a second solution is formed by stirring at a speed of 200 rpm to 300 rpm, such as 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm, or 300 rpm. This allows the second solution to be mixed more evenly.

[0052] In some embodiments of this application, the mass ratio of the first part of water to the second part of water is (8-10):1, for example, it can be 8:1, 9:1 or 10:1, etc. This is beneficial for controlling the viscosity of the sprayed slurry.

[0053] S3: Add phosphate fertilizer to the second solution to obtain an initial slurry with a pH of 6-6.7.

[0054] It is understandable that the pH value of the slurry can be adjusted according to the thickness of the ash layer on site. When the ash layer thickness is less than 3cm, add calcium dihydrogen phosphate to adjust the pH to 6.6±0.1; when the ash layer thickness is greater than 3cm, adjust the pH value to 6.2±0.1.

[0055] S4: Add grass seeds to the initial slurry to obtain the sprayed slurry.

[0056] Specifically, grass seeds can be added to the initial slurry and stirred evenly, and then sprayed as soon as possible within 3 hours to ensure the activity of the grass seeds.

[0057] In some embodiments of this application, the process of spraying the protective slurry can be as follows: using a fan-shaped nozzle (6mm orifice), the fan-shaped spray surface covers the airborne ash layer; the spraying pressure is 0.25MPa-0.4MPa (e.g., 0.25MPa, 0.3MPa, 0.35MPa, or 0.4MPa); the spraying angle is 70°-80° (e.g., 70°, 72°, 74°, 76°, 78°, or 80°); and the moving speed is 0.3m / s. This ensures thorough mixing while reducing the airborne material from the ash layer. The spraying operation should be completed in one continuous motion, maintaining a uniform speed. Simultaneously, the spraying is carried out horizontally from the top of the slope to the bottom, forming a circular slope protection strip. This process integrates chemical solidification, physical reinforcement, and ecological restoration technologies, achieving a dual improvement in the efficiency and ecological benefits (carbon sequestration + rapid vegetation restoration) of post-fire slope management. It is generally applicable to the management of low- to medium-risk burned areas. A well-designed and properly maintained slope spraying system can form a relatively complete vegetation protection layer with a coverage rate of 70% and gradual soil stabilization capabilities within three months. Landslides triggered by rainfall infiltration may occur in the first rainy season after a fire and 1-2 years or even longer after the fire; while the vegetation cover layer of this application has already completed the surface covering, filling of underground pores formed by the burning and decaying of roots, and cementation and reinforcement of the soil by new roots before that.

[0058] This application prepares a sprayed protective slurry using the above method. This sprayed protective slurry makes full use of the wood ash produced by the fire, transforming it from a source of disaster into fertilizer and a solidifying agent. This solves the problem of time-consuming and labor-intensive methods for clearing and blocking the source of the fire, and meets the needs of rapid treatment and reducing the risk of mudslides caused by rainfall in emergency treatment of burned areas.

[0059] The following specific embodiments illustrate the solution of this application. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0060] Example 1

[0061] 1. Material pretreatment

[0062] The wood fiber is made from pine pulp fiber (1 mm in length and 50:1 aspect ratio), which is soaked for 12 hours in advance to enhance its dispersibility.

[0063] Grass species should be selected according to the region: Amorpha fruticosa (deep root system) should be used on uphill slopes, tall fescue (mixed type) should be used on mid-slopes, and bermudagrass (shallow root system) should be used on downhill slopes, with 0.1% humic acid coating agent added.

[0064] Seed coating treatment:

[0065] Coating formula (substrate mass ratio): 60% diatomaceous earth + 30% biochar + 10% sodium carboxymethyl cellulose;

[0066] Functional additives: Gibberellin GA3 (50ppm), polyglutamic acid (0.5%), Bacillus subtilis (1×10⁻⁶) 6 CFU / g).

[0067] Coating process parameters: coating thickness is 150μm (controlling weight gain rate of 8-12%); drying conditions are fluidized bed drying at 35℃ until moisture content is ≤7%; the coating strength can withstand a breakage rate of <5% at a spray pressure of 0.8MPa.

[0068] 2. Preparation of sprayed protective slurry

[0069] (1) Substrate premixing: water-retaining agent (sodium polyacrylate 1.5 parts), crosslinking agent (PVA:CMC=1:2.5, 8 parts) and 65 parts water (25-30℃) are stirred for 10 minutes (speed is 250rpm);

[0070] (2) Adding main ingredients: Add calcium chloride (20 parts), lignin (20 parts), wood fiber (20 parts), and organic fertilizer (poultry and livestock manure compost: straw carbonization material: edible fungus residue = 3:2:1, 12 parts) to the mixed liquid in step (1) in sequence, add the ingredients at 3-minute intervals, add water and stir until the paste viscosity is ≥3000mPa·s;

[0071] (3) pH adjustment: Adjust the pH value of the slurry according to the thickness of the ash layer on site: when the ash layer thickness is 2cm, add calcium dihydrogen phosphate to pH=6.6±0.1, and finally add grass seeds (3 parts) and stir for 5 minutes.

[0072] 3. Spraying process

[0073] A fan-shaped nozzle (6mm orifice) is used to cover the airborne ash layer with a fan-shaped spray surface. The spray pressure is 0.3MPa, ensuring thorough mixing while preventing the ash layer from being stirred up. The spray angle is 80°, and the moving speed is 0.3m / s, completed in one pass while maintaining a constant speed. The spraying is carried out horizontally along the slope from the top to the bottom, forming a circular slope protection strip.

[0074] The results showed that Example 1 increased the seed retention rate to over 91%, the erosion resistance index of the solidified layer reached 90%, and the vegetation coverage rate reached 86% after 60 days. At the same time, carbon sequestration (2.3 t / ha) was achieved by consuming potassium carbonate in the ash layer.

[0075] Example 2

[0076] 1. Material pretreatment

[0077] The wood fiber is made from cedar pulp fiber (2mm in length and 60:1 aspect ratio), which is soaked for 12 hours in advance to enhance its dispersibility.

[0078] Grass species should be selected according to the region: Amorpha fruticosa (deep root system) should be used on uphill slopes, tall fescue (mixed type) should be used on mid-slopes, and bermudagrass (shallow root system) should be used on downhill slopes, with 0.1% humic acid coating agent added.

[0079] Seed coating treatment:

[0080] Coating formula (substrate mass ratio): 60% diatomaceous earth + 30% biochar + 10% sodium carboxymethyl cellulose;

[0081] Functional additives: Gibberellin GA3 (50ppm), polyglutamic acid (0.5%), Bacillus subtilis (1×10⁻⁶) 6 CFU / g).

[0082] Coating process parameters: coating thickness is 150μm (controlling weight gain rate of 8-12%); drying conditions are fluidized bed drying at 35℃ until moisture content is ≤7%; the coating strength can withstand a breakage rate of <5% at a spray pressure of 0.8MPa.

[0083] 2. Preparation of sprayed protective slurry

[0084] (1) Substrate premixing: water-retaining agent (sodium polyacrylate 1 part), crosslinking agent (PVA:CMC=1:3, 10 parts) and 73 parts water (25-30℃) are stirred for 10 minutes (speed is 300 rpm);

[0085] (2) Adding main ingredients: Add calcium chloride (25 parts), lignin (20 parts), wood fiber (20 parts), and organic fertilizer (poultry and livestock manure compost: straw carbonization material: edible fungus residue = 3:2:1, 15 parts) to the mixed liquid in step (1) in sequence, add the ingredients at 3-minute intervals, add water and stir until the paste viscosity is ≥3000mPa·s;

[0086] (3) pH adjustment: Adjust the pH value of the slurry according to the thickness of the ash layer on site: When the ash layer thickness is 4.2cm, add calcium dihydrogen phosphate to pH=6.2±0.1, and finally add grass seeds (3 parts) and stir for 5 minutes.

[0087] 3. Spraying process

[0088] A fan-shaped nozzle (6mm orifice) is used to cover the airborne ash layer with a fan-shaped spray surface. The spray pressure is 0.3MPa, ensuring thorough mixing while preventing the ash layer from being stirred up. The spray angle is 80°, and the moving speed is 0.3m / s, completed in one pass while maintaining a constant speed. The spraying is carried out horizontally along the slope from the top to the bottom, forming a circular slope protection strip.

[0089] The results showed that Example 2 increased the seed retention rate to over 85%, the erosion resistance index of the solidified layer reached 92%, and the vegetation coverage rate reached 78% after 60 days. At the same time, carbon sequestration (2.6t / ha) was achieved by consuming potassium carbonate in the ash layer, which solved the problem of synergistic consolidation of loose materials after fire and rapid vegetation recovery. It is suitable for the treatment of low- to medium-risk burned areas.

[0090] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A sprayed protective slurry, characterized in that, By weight, it includes: 15-20 parts lignin, 15-20 parts wood fiber, 2.5-3 parts grass seed, 2-15 parts organic fertilizer, 1-1.7 parts water-retaining agent, 15-25 parts calcium chloride, 5-10 parts crosslinking agent, 6-9 parts phosphate fertilizer and 63-80 parts water.

2. The sprayed protective slurry according to claim 1, characterized in that, The pH of the sprayed slurry is 6-6.

7.

3. The sprayed protective slurry according to claim 1 or 2, characterized in that, The water content of the sprayed slurry is 38%-47%.

4. The sprayed protective slurry according to claim 1 or 2, characterized in that, The viscosity of the sprayed slurry is 2500 mPa·s-4500 mPa·s.

5. The sprayed protective slurry according to claim 1 or 2, characterized in that, The phosphate fertilizer includes calcium dihydrogen phosphate; and / or, The water-retaining agent includes sodium polyacrylate.

6. The sprayed protective slurry according to claim 1 or 2, characterized in that, The wood fiber includes coniferous wood pulp fiber; and / or, The wood fibers are 0.5mm-2mm in length; and / or, The aspect ratio of the wood fibers is greater than or equal to 50:

1.

7. The sprayed protective slurry according to claim 1 or 2, characterized in that, The crosslinking agent comprises polyvinyl alcohol and sodium carboxymethyl cellulose, wherein the mass ratio of polyvinyl alcohol to sodium carboxymethyl cellulose is 1:(2-3); and / or, The organic fertilizer includes poultry and livestock manure compost, straw carbonization material, and edible mushroom residue, with the mass ratio of poultry and livestock manure compost, straw carbonization material, and edible mushroom residue being (3-2.5):(2-1.5):

1.

8. A method for preparing the sprayed protective slurry according to any one of claims 1-7, characterized in that, include: The water-retaining agent, the crosslinking agent, the calcium chloride, the lignin, the wood fiber, the organic fertilizer, and the first portion of water are mixed to form a first solution; Add a second part of water to the first solution to form a second solution, the viscosity of which is 2500 mPa·s-4500 mPa·s; The phosphate fertilizer was added to the second solution to obtain an initial slurry with a pH of 6-6.7; The grass seeds are added to the initial slurry to obtain the sprayed slurry.

9. The method according to claim 8, characterized in that, During the formation of the second solution, the second portion of water is added at a rate of 0.5 L / min to 1 L / min; and / or, The second solution is formed by stirring at a speed of 200 rpm to 300 rpm.

10. The method according to claim 8, characterized in that, The mass ratio of the first part of water to the second part of water is (8-10):1.