Ecological protection materials and methods for reinforcing embankments based on biomimetic mineralization

Abstract

This invention provides an ecological protection material and method for reinforcing embankments based on biomimetic mineralization, belonging to the field of embankment slope protection technology. The ecological protection material comprises: a first slurry A, which is a suspension formed by diatomaceous earth loaded with urease-producing bacteria powder and water; a second slurry B, which includes a calcium salt solution; and a third slurry C, which includes an ammonium bicarbonate solution; and a solid material D, which includes bentonite, basalt fiber, and potassium humate. The components in the ecological protection material, by weight percentage, are as follows: calcium salt 0.5%~1.0%, ammonium bicarbonate 0.6%~1.0%, diatomaceous earth loaded with urease-producing bacteria powder 5%~14%, bentonite 2%~5%, basalt fiber 0.8%~2%, potassium humate 0.4%~1%, and water 81%~87%.

Description

Technical Field

[0001] This invention relates to the field of embankment slope protection technology, and in particular to an ecological protection material and method for reinforcing embankments based on biomimetic mineralization. Background Technology

[0002] Highway slopes are frequently subjected to erosion by rainfall, causing the slope's soil and rock to disintegrate and be carried away by surface runoff, endangering driving safety. To prevent slope geological disasters, traditional methods typically employ retaining walls, anti-slide piles, and anchor bolts (cables) to stabilize the slope through physical support. However, ecological slope protection technologies such as three-dimensional vegetation concrete and root-anchored ecological slope protection are gaining popularity in the protection of low- to medium-risk embankment slopes.

[0003] Traditional rigid structures (such as concrete retaining walls) emit 200-300 kg of CO2 per square meter, while ecological slope protection can achieve negative carbon emissions through vegetation carbon sequestration, realizing the transformation of embankment slopes from "passive protection" to "active prevention and control + eco-friendliness", which has attracted industry attention.

[0004] However, the soil erosion resistance of ecological slope protection during the vegetation germination period is only 0.5kPa~1.2kPa, which is far below the 10kPa rainstorm erosion threshold. It takes 15~20 days for the vegetation to germinate after sowing and several months to form an effective root network. Summary of the Invention

[0005] In view of this, in order to address the problem that the soil has weak erosion resistance and is difficult to resist rainfall erosion during the vegetation germination period, this invention provides an ecological protection material and method for reinforcing embankments based on biomimetic mineralization, so as to achieve rapid solidification and shaping of ecological slopes.

[0006] According to one aspect of the present invention, the present invention provides an ecological protection material for reinforcing embankments based on a biomimetic mineralization method, the ecological protection material comprising:

[0007] First slurry A, which comprises a suspension formed by diatomaceous earth-loaded urease bacteria powder and water;

[0008] Second slurry B, which includes a calcium salt solution;

[0009] The third slurry C, comprising an ammonium bicarbonate solution; and

[0010] Solid material D includes bentonite, basalt fiber, and potassium humate.

[0011] The components of the eco-curing material, by weight percentage, are as follows:

[0012] Calcium salt 0.5%~1.0%, ammonium bicarbonate 0.6%~1.0%, diatomaceous earth-loaded urease-bacterial powder 5%~14%, bentonite 2%~5%, basalt fiber 0.8%~2%, potassium humate 0.4%~1%, water 81%~87%.

[0013] According to another aspect of the present invention, the present invention provides an ecological protection method for reinforcing embankments based on biomimetic mineralization, comprising:

[0014] Provide the ecological protection materials mentioned above;

[0015] The embankment slope is cut to a slope with a preset slope, and solid material D is spread on the slope.

[0016] First grout A, second grout B, and third grout C are sprayed sequentially on the slope to form a solidified adhesive layer;

[0017] Nutrient-rich soil containing grass seeds is sprayed onto the solidified cementitious layer to form a grass seed layer; and

[0018] A three-dimensional geotextile vegetation mat is laid on the grass seed layer.

[0019] The ecological protection material provided by this invention achieves ecological reinforcement of embankment slopes by synergistically combining biomimetic chemical mineralization and microbial solidification technologies. Specifically, it utilizes a calcium salt-ammonium bicarbonate chemical system with diatomaceous earth-loaded urease-producing bacteria powder. The highly active urease-producing bacteria create an alkaline microenvironment through metabolic activity, catalyzing the instantaneous decomposition of ammonium bicarbonate to generate high-concentration CO3. 2- The Ca dissociation of calcium salt solution 2+ With CO3 2- In combination, calcite-type calcium carbonate is deposited on the surface of basalt fibers and in the soil, forming a rigid framework with a compressive strength greater than 25 kPa. Simultaneously, urease-producing bacteria secrete urease, catalyzing and replenishing the system's active carbonate ions and secreting colloidal extracellular polysaccharides, which encapsulate the original sand particles on the embankment slope to form a flexible cemented network. The calcium salt-ammonium bicarbonate chemical system produces NH4 as a byproduct. + This process provides a nitrogen source for soil microorganisms, while the nitrogen source, potassium humate, and bentonite maintain soil pH and ion balance, significantly activating and prolonging urease activity. In other words, chemical mineralization provides an alkaline environment for microorganisms, activates urease activity centers, accelerates mineralization efficiency, and thus enables the rapid solidification and molding of ecological protection materials.

[0020] According to the ecological protection material provided by this invention, the calcium salt-ammonium bicarbonate chemical system not only accelerates initial solidification but also provides continuous bonding force for subsequent vegetation root growth. The potassium humate-bentonite system, combined with a grass seed layer, can accelerate vegetation growth, enhance root anchoring force, and form a permanent ecological protection layer for embankment slopes, overcoming the limitations of slow solidification speed and high brittleness of purely chemical mineralization in traditional microbial methods. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0022] Figure 1 A flowchart of an ecological protection method for reinforcing embankments based on biomimetic mineralization, provided for embodiments of the present invention; and

[0023] Figure 2 A schematic diagram of ecological protection of embankment slopes provided in an embodiment of the present invention;

[0024] Explanation of reference numerals in the attached figures:

[0025] 1-Slope surface; 2-Cemented layer; 3-Grass seed layer; 4-Geotechnical three-dimensional vegetation mat. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. However, this invention can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the invention thorough and complete, and to fully convey the scope of the invention to those skilled in the art. In the accompanying drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated, and the same reference numerals denote the same elements throughout.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] In related technologies, traditional concrete retaining walls have a long construction cycle, while existing ecological slope protection has a soil erosion resistance of only 0.5 kPa to 1.2 kPa during the vegetation germination period, which is far below the 10 kPa rainstorm erosion threshold. After the vegetation is sown, it takes 15 to 20 days to germinate and several months to form an effective root network, which poses a risk of soil erosion during the 15 to 20 day window period.

[0029] In view of this, the present invention provides an ecological protection material and method for reinforcing embankments based on biomimetic mineralization. The ecological protection material can be rapidly solidified and formed, and the solidified cementitious layer formed after the ecological protection material is used on the embankment slope has high compressive strength and high erosion resistance, which can improve the problem of weak soil erosion resistance during the vegetation germination period.

[0030] According to an exemplary embodiment of the present invention, the present invention provides an ecological protection material for reinforcing embankments based on a biomimetic mineralization method, the ecological protection material comprising:

[0031] First slurry A, which comprises a suspension formed by diatomaceous earth-loaded urease bacteria powder and water;

[0032] Second slurry B, which includes a calcium salt solution; and

[0033] The third slurry C, comprising an ammonium bicarbonate solution; and

[0034] Solid material D includes bentonite, basalt fiber, and potassium humate.

[0035] The components of the ecological protection material, by weight percentage, are as follows:

[0036] Calcium salt 0.5%~1.0%, ammonium bicarbonate 0.6%~1.0%, diatomaceous earth-loaded urease-bacterial powder 5%~14%, bentonite 2%~5%, basalt fiber 0.8%~2%, potassium humate 0.4%~1%, water 81%~87%.

[0037] In embodiments of the present invention, the weight percentage of calcium salt is, for example, 0.5%, 0.6%, 0.8%, 1.0%, but not limited to the values ​​listed; the weight percentage of ammonium bicarbonate is, for example, 0.6%, 0.8%, 1.0%, but not limited to the values ​​listed; the weight percentage of diatomaceous earth-supported urease bacteria powder is, for example, 5%, 6%, 8%, 10%, 12%, 14%, but not limited to the values ​​listed; the weight percentage of bentonite is, for example, 2%, 3%, 4%, 5%, but not limited to the values ​​listed; the weight percentage of basalt fiber is, for example, 0.8%, 1%, 1.5%, 1.6%, 1.8%, 2%, but not limited to the values ​​listed; and the weight percentage of potassium humate is, for example, 0.4%, 0.5%, 0.6%, 0.8%, 1%, but not limited to the values ​​listed.

[0038] In embodiments of the present invention, the calcium salt includes at least one of calcium chloride, calcium nitrate, calcium acetate, and calcium lactate.

[0039] According to an exemplary embodiment of the present invention, the present invention provides an ecological protection method for reinforcing embankments based on biomimetic mineralization, such as... Figure 1 and Figure 2 As shown, it includes: operations S1 to S5.

[0040] Operate S1 to provide ecological protection materials.

[0041] In embodiments of the present invention, solid material D comprises a mixture of bentonite, basalt fiber, and potassium humate. The weight ratio of bentonite, basalt fiber, and potassium humate is (2~5):(0.8~2):(0.4~1), for example, 2:0.8:0.5, 2:2:1, 3:2:1, 4:2:1, 5:2:1, but is not limited to the values ​​listed.

[0042] In the embodiments of this invention, insufficient addition of bentonite fails to effectively retain water and slowly release ammonium ions, resulting in poor initial curing conditions. Excessive addition of bentonite hinders the contact between urease bacteria and nutrients (organic and inorganic nutrient molecules in diatomaceous earth-loaded urease bacteria powder, ammonium bicarbonate, and potassium humate), inhibiting the catalytic mineralization of microorganisms and leading to slower solidification and reduced strength. Insufficient addition of basalt fiber reduces its reinforcing and bridging effects, decreasing the toughness and crack resistance of the solidified cement layer. Excessive addition of basalt fiber makes it difficult to disperse evenly in the mixture, causing it to clump and affecting the uniform deposition of calcium carbonate. Insufficient addition of potassium humate makes it difficult to effectively maintain soil pH and ion balance, thus weakening its effects on soil improvement and promoting root growth, failing to achieve the ecological effect of root penetration in the short term. Adding too much potassium humate will introduce excessive potassium ions and organic matter, altering the local pH and ionic strength, which is detrimental to the activity of urease bacteria and affects the initial curing strength.

[0043] By controlling the weight ratio of bentonite, basalt fiber, and potassium humate within the aforementioned range, bentonite can effectively achieve water retention and slow-release effects, basalt fiber can effectively enhance and improve toughness, and potassium humate can effectively improve soil and promote growth. Through the synergistic effect of these three materials, significant synergistic benefits are achieved in terms of workability, curing strength, and ecological effects.

[0044] In embodiments of the present invention, bentonite also has the effect of promoting microbial activity, improving soil structure, and enhancing the utilization rate of nutrients in the soil.

[0045] In embodiments of the present invention, the basalt fiber is preferably 20mm to 30mm in length, for example, 20mm, 22mm, 24mm, 28mm, or 30mm, but is not limited to the values ​​listed.

[0046] According to embodiments of the present invention, the 20-30 mm length is much larger than the diameter of most soil particles. These basalt fibers, randomly distributed in the soil, can overlap and intertwine to form a continuous three-dimensional spatial network structure, firmly binding the soil particles together. This also prevents the generation and propagation of cracks caused by stress concentration, significantly improving the toughness and crack resistance of the solidified cement layer. If the fibers are too long, for example, >50 mm, they may become entangled and clumped together, making it difficult to mix evenly with solid materials such as bentonite and potassium humate. If the basalt fibers are too short (for example, less than 20 mm), they cannot effectively overlap to form a continuous network, failing to macroscopically improve the toughness and crack resistance of the entire solidified cement layer.

[0047] In embodiments of the present invention, the tensile strength of the basalt fiber is greater than or equal to 1200 MPa. If the strength of the basalt fiber is too low (e.g., below 1200 MPa), when the solidified cement layer is under stress, the basalt fiber will break or be pulled out before the soil matrix, failing to transfer and disperse stress, thus negating the reinforcement effect. By using basalt fiber with a tensile strength greater than or equal to 1200 MPa, it is ensured that the basalt fiber effectively performs its reinforcement function under stress.

[0048] In an embodiment of the present invention, a first slurry A is prepared during on-site construction. Specifically, the first slurry A is a suspension formed by reconstituted diatomaceous earth-loaded urease bacteria powder with water. The mass ratio of water to diatomaceous earth-loaded urease bacteria powder in the first slurry A is 8:1 to 12:1, for example, 8:1, 9:1, 10:1, 11:1, or 12:1, but not limited to these values. If the mass ratio is too low (e.g., below 8:1), the urease bacteria will be unevenly distributed and their activity will be limited; it will also be difficult to form a uniform cured cement layer, affecting the curing strength and erosion resistance. If the mass ratio is too high (e.g., greater than 12:1), the first slurry A will be too thin and prone to flowing, making it difficult to stay on the slope; and the concentration of the effective ingredient will be low, resulting in a slow curing reaction; this may lead to insufficient strength of the cured cement layer and a decrease in erosion resistance.

[0049] In embodiments of the present invention, the urease-producing bacteria may be, for example, Bacillus pasteurellii. The preparation process of the diatomaceous earth-loaded urease-producing bacteria powder includes: [the process involves] mixing bacteria at a viable concentration of 10... 6 CFU / mL ~10 7 A suspension of urease bacteria with a concentration of CFU / mL was mixed with diatomaceous earth at a mass ratio of 1:1 to 1:3, and then dried into a powder by vacuum adsorption and airflow drying to obtain a viable bacterial concentration of ≥10⁻⁶ CFU / mL. 9 A diatomaceous earth-loaded urease-containing bacterial powder with a concentration of CFU / g is prepared as a powder for easy storage.

[0050] In some embodiments, the urease-producing bacteria may be, for example, Bacillus megaterium or Bacillus pasteurellium.

[0051] In embodiments of the present invention, the pore size of the diatomaceous earth is 5~10μm, for example, 5μm, 6μm, 7μm, 8μm, 10μm, but not limited to the values ​​mentioned; the specific surface area of ​​the diatomaceous earth is greater than or equal to 20m². 2 / g. If the pore size of diatomaceous earth is too large, the bacterial solution can easily penetrate the pores during the actual cementation reaction, making it impossible to effectively use capillary action to fix the urease bacteria inside the pores. Secondly, during subsequent resolution or slurry spraying and rinsing, the bacterial solution is easily detached and lost from the pores on the carrier surface. If the pore size of diatomaceous earth is too small, substances such as calcium sources will have difficulty diffusing into the deep closed micropores to contact the bacterial solution, affecting the uniformity of cementation and the curing effect. By controlling the pore size of diatomaceous earth to 5~10μm, the direct damage of the bacterial solution to the external high pH environment can be prevented, providing a physical shield for the bacteria. This ensures the diffusion channels for water and nutrients, maintains a relatively high local ion concentration, accelerates the calcium carbonate precipitation rate, and makes the resulting cured cement layer denser and more uniform.

[0052] In embodiments of the present invention, the second slurry B comprises a calcium salt solution, wherein the calcium salt includes at least one selected from calcium chloride, calcium nitrate, calcium acetate, and calcium lactate. The concentration of the calcium salt solution is 0.6 mol / L to 1.0 mol / L, for example, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, and 1.0 mol / L, but is not limited to these values. If the concentration of the calcium salt is too low, the amount of calcium carbonate generated will be insufficient, resulting in insufficient solidification strength. If the concentration is too high, it will inhibit microbial activity, causing material waste and economic losses. The above-mentioned concentration range provides a sufficiently high concentration of calcium ions, enabling them to react fully with carbonate ions to generate a large amount of calcium carbonate precipitate. This is the material basis for the formation of a high-strength solidified cementitious layer by the cemented soil particles.

[0053] In embodiments of the present invention, the third slurry C comprises an ammonium bicarbonate solution with a concentration of 0.8 mol / L to 1.2 mol / L, for example, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, or 1.2 mol / L, but not limited to these values. On the one hand, a concentration above 0.8 mol / L provides sufficient reactants for the mineralization reaction and also increases the pH value during the reaction, ensuring high activity of the urease bacteria, allowing the secreted extracellular polymers to intertwine with calcium carbonate crystals to form a tough structure. On the other hand, this concentration range ensures that when the calcium salt and ammonium bicarbonate solutions are sprayed in approximately equal volumes, they approach the optimal stoichiometric ratio, avoiding excessive amounts of either reactant. Too low a concentration of ammonium bicarbonate solution leads to a slow reaction, low intensity, and insufficient nutrients. Too high a concentration of ammonium bicarbonate solution inhibits bacterial activity and pollutes the environment.

[0054] In embodiments of the present invention, the volume ratio of ammonium bicarbonate solution to calcium salt solution is 1:1 to 1:2, for example, it can be 1:1, 1:1.5, or 1:2, but is not limited to the values ​​mentioned.

[0055] In embodiments of the present invention, the molar ratio of calcium salt to ammonium bicarbonate is 1:1.2 to 1:1.5, for example, 1:1.2, 1:1.3, or 1:1.5, but is not limited to these values. If the molar ratio of calcium salt to ammonium bicarbonate is too low, it will result in raw material waste, as sufficient calcium carbonate cement cannot be formed; furthermore, it will inhibit urease activity and growth, leading to a decrease in subsequent catalytic efficiency. If the molar ratio of calcium salt to ammonium bicarbonate is too high, the CO3 provided by ammonium bicarbonate will be insufficient. 2- Insufficient calcium carbonate concentration can lead to insufficient precipitation of calcium ions, resulting in reduced calcium carbonate cementation and decreased curing strength. At the same time, excessively high calcium ion concentration may inhibit urease activity.

[0056] Operation S2 cuts the embankment slope to a slope surface 1 with a preset slope, and spreads the aforementioned solid material D on the slope surface 1.

[0057] In embodiments of the present invention, the preset slope is 1:1.5 to 1:2, for example, 1:1.5, 1:1.6, 1:2, but is not limited to the values ​​mentioned.

[0058] In embodiments of the present invention, the slope range is determined after considering slope stability, construction feasibility, and material properties. If the slope is too steep (e.g., >1:1.5), the sprayed grout and injected nutrient soil will flow downwards or slide down due to gravity, resulting in uneven distribution of materials on the slope surface; the flowing grout cannot fully solidify at the predetermined location; a steeper slope increases surface runoff velocity and scouring force, requiring higher scouring resistance from the solidified cement layer and vegetation layer. If the slope is too gentle (e.g., <1:2), excessive slope cutting will increase the amount of earthwork.

[0059] In an embodiment of the present invention, before spreading the above-mentioned solid material on the slope 1, loose stones and tree roots on the slope are removed to ensure the quality of subsequent construction.

[0060] Operation S3 involves sequentially spraying the first slurry A, the second slurry B, and the third slurry C onto the slope surface where solid material D is spread, in order to form a solidified adhesive layer 2.

[0061] In embodiments of the present invention, the volume ratio of the first slurry A, the second slurry B, and the third slurry C in each cycle is 1:1:1 or close to 1:1:1. The spraying time between two adjacent cycles is approximately 2 to 4 hours to ensure sufficient penetration and reaction of the slurry, achieving layered curing.

[0062] In an embodiment of the present invention, a high-pressure spray gun is used for cyclic spraying. First, 60% of the slope is covered by longitudinal spraying, and after initial setting, it is sprayed laterally to cover 100% of the slope, ensuring the uniformity of the cured adhesive layer 2.

[0063] In embodiments of the present invention, the thickness of the cured adhesive layer 2 is 10cm to 15cm, for example, 10cm, 12cm, 13cm, 14cm, or 15cm, but not limited to these values. If the thickness is too small, the adhesive strength and erosion resistance will be insufficient, the impermeability will be poor, the root anchoring will be weak, short-term protection will fail, and the slope will be easily eroded and damaged. If the thickness is too large, firstly, the cost will increase; secondly, an excessively thick cured adhesive layer will form a dense and hard plate, hindering the downward penetration of plant roots; and thirdly, a thicker cured adhesive layer requires more cycles of spraying and a longer curing time, leading to extended construction periods and increased labor and machinery costs.

[0064] Operation S4 sprays nutrient soil containing grass seeds onto the solidified cement layer 2 to form the grass seed layer 3.

[0065] In an embodiment of the present invention, a hydraulic hydroseeding machine is used to spread nutrient soil containing grass seeds on the solidified cement layer 2, and the nutrient soil with grass seeds is sprayed onto the slope surface, forming a grass seed layer 3 with a thickness of 2cm to 3cm.

[0066] In some embodiments, the grass species are a mixture of shrubs and grass seeds, the grass seeds including at least one of ryegrass, tall fescue, white clover and bermudagrass, and the shrubs including at least one of firethorn, privet, lespedeza and amorpha.

[0067] In an embodiment of the present invention, the grass seed is bermudagrass + tall fescue, and the shrub is amorpha fruticosa + lespedeza. The grass seed and shrub are mixed and sown at a mass ratio of 3:1 to increase the spatial distribution density of the root system.

[0068] Operate S5 to lay the geotextile three-dimensional vegetation mat 4 on the grass seed layer 3.

[0069] In some embodiments, the above-described ecological solidification method further includes: anchoring the geotextile three-dimensional vegetation mat 4 onto the grass seed layer 3 using U-shaped nails.

[0070] In an embodiment of the present invention, the aperture of the geotextile three-dimensional vegetation net mat 4 is, for example, 10cm×10cm, and the spacing of the U-shaped nail anchors is less than or equal to 50cm.

[0071] In an embodiment of the present invention, the mineralization byproduct NH4 + It provides nitrogen source for vegetation; potassium humate improves soil aggregate structure, promotes grass seeds to penetrate the mineralized layer (solidified cementing layer) within 7 days, and the roots of grass and shrub mixed sowing become entangled with the calcium carbonate network to form a permanent anchoring system.

[0072] According to an exemplary embodiment of the present invention, the present invention provides an ecological protection structure prepared by the above-described ecological protection method, comprising:

[0073] The cured adhesive layer 2 is located on the slope surface of the embankment.

[0074] Grass seed layer 3 is located on the solidified cement layer 2, and grass seed layer 3 includes nutrient soil containing grass seeds;

[0075] The geotextile three-dimensional vegetation mat 4 is laid on the grass seed layer 3.

[0076] The following example illustrates the ecological protection material and method for reinforcing road embankments based on biomimetic mineralization. It should be noted that this example is merely a specific embodiment of the present invention and does not limit the scope of protection of the present invention.

[0077] Example 1

[0078] Referring to Table 1, prepare the first slurry A. Specifically, take a suspension of Bacillus pasteurellium (concentration 2 × 10⁻⁶). 8 100g of diatomaceous earth (CFU / mL) was mixed with 120g of diatomaceous earth and dried by vacuum adsorption and airflow to prepare 120g of diatomaceous earth-loaded urease bacteria powder. The 120g of diatomaceous earth-loaded urease bacteria powder was then redissolved with 960.0g of water to form a suspension.

[0079] Prepare the second slurry B, specifically, prepare 120.0 mL of 1.0 mol / L calcium chloride solution.

[0080] Prepare the third slurry C, specifically, prepare 140.0 mL of 1.2 mol / L ammonium bicarbonate solution.

[0081] Solid material D is provided, specifically, 30.0g of bentonite, 15.0g of basalt fiber and 6.0g of potassium humate are mixed to obtain solid material D.

[0082] The construction of a simulated slope was carried out, with the slope base being a sandy clay filling model. Specifically, solid material D was spread on a simulated embankment slope with a slope of 1:1.5 and dimensions of 1m × 0.5m. The first grout A, the second grout B, and the third grout C were sprayed in sequence four times. Then, it was cured at 25℃ for 24 hours and bonded for 7 days to obtain a solidified bonded layer.

[0083] The compressive strength of the cured adhesive layer formed in Example 1 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer in Example 1 was found to be 1.83 MPa, as shown in Table 2.

[0084] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion rate of the cured adhesive layer in Example 1 was found to be approximately 0.06 kg / m². 2 The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0085] Example 2

[0086] The cured cement layer was obtained using the same method as in Example 1. The difference from Example 1 is that 28.0g of bentonite, 15.0g of basalt fiber and 7.5g of potassium humate were mixed to obtain solid material D (i.e., the mass ratio of bentonite, basalt fiber and potassium humate was 3.7:2:1).

[0087] The compressive strength and erosion amount of the cured adhesive layer prepared in Example 2 were tested using the same method as in Example 1. The test results are shown in Table 2.

[0088] Example 3

[0089] The cured adhesive layer was obtained using the same method as in Example 1. The difference from Example 1 was that the mass ratio of water to diatomaceous earth-loaded urease bacteria powder was adjusted to 8.3:1, that is, 120g of diatomaceous earth-loaded urease bacteria powder was redissolved with 1000.0g of water to form a suspension.

[0090] The compressive strength and erosion amount of the cured adhesive layer prepared in Example 3 were tested using the same method as in Example 1. The test results are shown in Table 2.

[0091] Example 4

[0092] The cured adhesive layer was obtained using the same method as in Example 1, except that the calcium salt concentration was adjusted to 0.8 mol / L.

[0093] The compressive strength and erosion amount of the cured adhesive layer prepared in Example 4 were tested using the same method as in Example 1. The test results are shown in Table 2.

[0094] Example 5

[0095] The cured adhesive layer was obtained using the same method as in Example 1, except that 140.0 mL of a 0.9 mol / L ammonium bicarbonate solution was prepared.

[0096] The compressive strength and erosion amount of the cured adhesive layer prepared in Example 5 were tested using the same method as in Example 1. The test results are shown in Table 2.

[0097] Example 6

[0098] The cured adhesive layer was obtained using the same method as in Example 1, except that 147.0 mL of a 1.2 mol / L ammonium bicarbonate solution was prepared.

[0099] The compressive strength and erosion amount of the cured adhesive layer prepared in Example 6 were tested using the same method as in Example 1. The test results are shown in Table 2.

[0100] Example 7

[0101] The cured adhesive layer was obtained using the same method as in Example 1, except that a suspension of Bacillus pasteurellium (concentration 2×10⁻⁶) was used. 8 125g of diatomaceous earth (CFU / mL) was mixed with 130g of diatomaceous earth and dried under vacuum to produce 130g of diatomaceous earth-loaded urease-containing bacterial powder. 110.0mL of 1.0 mol / L calcium chloride solution was prepared, and the amount of bentonite was increased to 40g.

[0102] The compressive strength and erosion amount of the cured adhesive layer prepared in Example 7 were tested using the same method as in Example 1. The test results are shown in Table 2.

[0103] Example 8

[0104] The cured cement layer was obtained using the same method as in Example 1. The difference from Example 1 is that 30.0g of bentonite, 15.0g of basalt fiber, and 10g of potassium humate were mixed to obtain solid material D (i.e., the weight ratio of bentonite, basalt fiber, and potassium humate was 3:1.5:1).

[0105] The compressive strength and erosion amount of the cured adhesive layer prepared in Example 8 were tested using the same method as in Example 1. The test results are shown in Table 2.

[0106] Comparative Example 1

[0107] The cured adhesive layer was obtained using the same method as in Example 1, except that the first slurry A was not prepared with a suspension of Bacillus pasteurellii.

[0108] The compressive strength of the cured adhesive layer formed in Comparative Example 1 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer in Comparative Example 1 was found to be 1.45 MPa, as shown in Table 2.

[0109] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion of the cured adhesive layer in Comparative Example 1 was approximately 0.53 kg / m². 2The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0110] Comparative Example 2

[0111] The cured adhesive layer was obtained using the same method as in Example 1, except that the first slurry was not prepared without calcium chloride.

[0112] The compressive strength of the cured adhesive layer formed in Comparative Example 2 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer in Comparative Example 2 was found to be 1.22 MPa, as shown in Table 2.

[0113] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion of the cured adhesive layer in Comparative Example 2 was found to be approximately 0.81 kg / m². 2 The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0114] Comparative Example 3

[0115] The cured adhesive layer was obtained using the same method as in Example 1, except that the solid material did not include basalt fiber.

[0116] The compressive strength of the cured adhesive layer formed in Comparative Example 3 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer in Comparative Example 3 was found to be 1.62 MPa, as shown in Table 2.

[0117] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion rate of the cured adhesive layer in Comparative Example 3 was approximately 0.21 kg / m². 2 The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0118] Comparative Example 4

[0119] The cured adhesive layer was obtained using the same method as in Example 1, except that the solid material did not include bentonite.

[0120] The compressive strength of the cured adhesive layer formed in Comparative Example 4 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer in Comparative Example 4 was found to be 1.41 MPa, as shown in Table 2.

[0121] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion of the cured adhesive layer in Comparative Example 4 was approximately 0.33 kg / m². 2 The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0122] Comparative Example 5

[0123] The cured adhesive layer was obtained using the same method as in Example 1, except that it contained calcium salt, but the weight percentage of calcium salt was 0.45%.

[0124] The compressive strength of the cured adhesive layer formed in Comparative Example 5 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer in Comparative Example 5 was found to be 1.36 MPa, as shown in Table 2.

[0125] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion of the cured adhesive layer in Comparative Example 5 was approximately 0.26 kg / m². 2 The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0126] Comparative Example 6

[0127] The cured adhesive layer was obtained using the same method as in Example 1, except that the diatomaceous earth-loaded urease-containing powder was replaced with a suspension of Bacillus pasteurellii with an equal amount of viable bacteria (concentration 2 × 10⁻⁶). 8 100g (CFU / mL), without diatomaceous earth.

[0128] The compressive strength of the cured adhesive layer formed in Comparative Example 6 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer of Comparative Example 6 was found to be 1.50 MPa, as shown in Table 2.

[0129] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion rate of the cured adhesive layer in Comparative Example 6 was approximately 0.29 kg / m². 2 The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0130] Comparative Example 7

[0131] The cured adhesive layer was obtained using the same method as in Example 1, except that 140 mL of 1.2 mol / L ammonium bicarbonate solution was replaced with 140 mL of 1.2 mol / L urea solution.

[0132] The compressive strength of the cured adhesive layer formed in Comparative Example 7 was tested using a universal testing machine (GB / T 50081-2019). The compressive strength of the cured adhesive layer of Comparative Example 7 was found to be 1.65 MPa, as shown in Table 2.

[0133] Artificial rainfall was simulated on the cured adhesive layer using a spraying device. The artificial rainfall intensity was 20 mm / h, and the erosion time was 1 hour. The erosion of the cured adhesive layer in Comparative Example 7 was approximately 0.15 kg / m². 2 The spraying equipment is a pneumatic spray gun with a pressure of 1.0 MPa and a nozzle diameter of 1 mm.

[0134] Table 1

[0135]

[0136] Continued from the table above

[0137]

[0138] Table 2

[0139]

[0140] According to the embodiments and comparative examples described above, by adding urease bacteria to the ecological protection material used for embankment slopes and adjusting the content of each component, the compressive strength and erosion resistance of the cured cementitious layer formed by the ecological protection material can be adjusted.

[0141] In comparison to Comparative Example 1, Example 1 of the present invention uses raw materials including Bacillus pasteurellium suspension to form a cured cement layer. The compressive strength of the cured cement layer is improved, and the erosion is significantly reduced. This is because diatomaceous earth-loaded urease bacteria powder is added. The extracellular polymers secreted by urease bacteria intertwine with calcium carbonate crystals, encapsulating and connecting a large number of fine calcium carbonate crystals, thereby improving the compressive strength of the cured cement layer.

[0142] Compared to Comparative Example 2, the first slurry of Example 1 of the present invention includes calcium chloride, which can provide sufficient Ca. 2+ With CO3 2- The bonds combine to form calcium carbonate, thereby increasing the compressive strength of the cured adhesive layer.

[0143] Compared to Comparative Example 3, the solid material in Example 1 of the present invention includes basalt fiber, and the compressive strength of the solid cement layer in Example 1 is improved. This is because Example 1 utilizes the reinforcing and bridging effect of basalt fiber in the solid cement layer, thereby improving the compressive strength and crack resistance of the solid cement layer.

[0144] Compared to Comparative Example 4, the solid material in Example 1 of this invention includes bentonite, and the compressive strength of the solid cementing layer in Example 1 is improved. This is because bentonite, through its hydration and expansion characteristics, plays a key role in micro-filling, water retention and synergistic cementation in the solidified cementing layer. It can not only fill the pores to make the structure denser and improve the strength, but the gel it forms also provides a stable moisture environment for microbial mineralization reactions and promotes the formation of more calcium carbonate.

[0145] Compared to Comparative Example 5, the weight percentage of the calcium salt solution in Example 1 of this invention was adjusted to 0.96%. The compressive strength of the solid cementing layer in Example 1 was significantly improved because calcium ions are a key reactant for microbial-induced calcium carbonate precipitation. The higher calcium ion concentration in Example 1 provided more abundant reaction substrate for the urease bacteria, resulting in the formation of a greater amount of calcium carbonate crystals. This more effectively cements soil particles, fills pores, and forms a denser and stronger overall structure, thus significantly improving compressive strength. Simultaneously, the robust cemented structure also enhances its resistance to erosion.

[0146] Compared to Comparative Example 6, Example 1 of this invention uses diatomaceous earth-supported urease bacteria powder. The compressive strength of the solid cement layer in Example 1 is significantly improved and the erosion is lower. This is because the first slurry is a diatomaceous earth-stabilized suspension, which is easy to spray and has good adhesion to the slope. The diatomaceous earth carrier protects, slows down, adsorbs, and disperses the urease bacteria, ensuring the effective retention and uniform distribution of the bacterial agent on the slope. This avoids the chemical impact caused by the instantaneous and direct envelopment of the bacteria by high-concentration chemicals, ensuring its high activity. The extracellular polymer calcium carbonate crystals secreted by the urease bacteria interweave to form a dense cement structure with low porosity and interlocking crystals, while effectively reducing permeability and enhancing erosion resistance.

[0147] Compared to Comparative Example 7, Example 1 of this invention uses ammonium bicarbonate instead of urea. The compressive strength of the cured cement layer in Example 1 is significantly improved and the erosion is lower. On the one hand, this is because the ammonium bicarbonate solution reacts rapidly and directly, which is conducive to the formation of stable calcium carbonate crystals, and it is weakly alkaline in aqueous solution. This pH condition is favorable for the formation and precipitation of calcium carbonate, thereby improving the compressive strength of the cured cement layer. Although urea solution can generate carbonate ions to produce calcium carbonate under the catalysis of urease, the reaction of urea hydrolysis to produce carbon dioxide is relatively slow, resulting in a slower rate of carbonate ion formation, which affects the formation of the cured cement layer. On the other hand, urea solution releases a large amount of ammonia gas during the hydrolysis reaction. The ammonia gas is further converted into ammonia water in water, making the solution strongly alkaline. This higher pH value may promote the escape of more ammonia gas, affecting the amount and stability of calcium carbonate formation.

[0148] The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify the corresponding elements does not imply that the element has any ordinal number, nor does it represent the order of one element with another element, or the order of manufacturing methods. The use of these ordinal numbers is only to enable a named element to be clearly distinguished from another element with the same name.

[0149] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ecological protection material for reinforcing road embankments based on biomimetic mineralization, characterized in that, The ecological protection materials include: First slurry A, comprising a suspension formed by diatomaceous earth-loaded urease bacteria powder and water; Second slurry B, the second slurry B comprising a calcium salt solution; The third slurry C comprises an ammonium bicarbonate solution; and Solid material D, wherein solid material D comprises bentonite, basalt fiber and potassium humate, The components of the ecological protection material, by weight percentage, are as follows: Calcium salt 0.5%~1.0%, ammonium bicarbonate 0.6%~1.0%, diatomaceous earth-loaded urease-bacterial powder 5%~14%, bentonite 2%~5%, basalt fiber 0.8%~2%, potassium humate 0.4%~1%, water 81%~87%.

2. The ecological protection material according to claim 1, characterized in that, The calcium salt includes at least one of calcium chloride, calcium nitrate, calcium acetate, and calcium lactate.

3. The ecological protection material according to claim 1, characterized in that, The viable bacterial concentration of the diatomaceous earth-loaded urease-containing powder is greater than or equal to 10. 9 CFU / g; The moisture content of the diatomaceous earth-loaded urease-containing bacterial powder is less than or equal to 3%. Diatomaceous earth has a pore size of 5μm~10μm and a specific surface area of ​​≥20m². 2 / g.

4. An ecological protection method for reinforcing road embankments based on biomimetic mineralization, characterized in that, include: Provide ecological protection materials as described in any one of claims 1 to 3; The embankment slope is cut to a slope with a preset slope, and solid material D is spread on the slope. First slurry A, second slurry B, and third slurry C are sequentially sprayed onto the slope to form a cured adhesive layer; Nutrient soil containing grass seeds is sprayed onto the solidified cementitious layer to form a grass seed layer; as well as A geotextile three-dimensional vegetation mat is laid on the grass seed layer.

5. The ecological protection method according to claim 4, characterized in that, The mass ratio of water to diatomaceous earth-loaded urease-bacterial powder in the first slurry A ranges from 8:1 to 12:

1.

6. The ecological protection method according to claim 5, characterized in that, Urease-producing bacteria include Bacillus pasteurellii.

7. The ecological protection method according to claim 5, characterized in that, The preparation method of the diatomaceous earth-loaded urease-bacterial powder includes: The live bacteria concentration was 10. 6 CFU / g ~10 7 A CFU / g suspension of urease bacteria is mixed with diatomaceous earth at a mass ratio of 1:1 to 1:3, and then vacuum adsorption and airflow drying are performed to produce the diatomaceous earth-loaded urease bacteria powder with a moisture content of less than or equal to 3%.

8. The ecological protection method according to claim 4, characterized in that, The concentration of the calcium salt solution is 0.6 mol / L to 1.0 mol / L; The concentration of the ammonium bicarbonate solution is 0.8 mol / L to 1.2 mol / L; The molar ratio of the calcium salt to ammonium bicarbonate is 1:1.2 to 1:1.

5.

9. The ecological protection method according to claim 4, characterized in that, The preset slope is 1:1.5 to 1:

2.

10. The ecological protection method according to claim 4, characterized in that, It also includes using U-shaped nails to anchor the geotextile three-dimensional vegetation mat onto the grass seed layer.

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