An ecological soil spraying protective agent and its preparation and application

Abstract

The present application belongs to the field of vegetation restoration and soil and water conservation, and particularly relates to an ecological soil spraying protective agent, a preparation method and application thereof. The ecological soil spraying protective agent comprises core material 1-20 parts and auxiliary material 80-100 parts in mass fraction, the core material comprises potassium aluminum sulfate, sodium sulfate, sodium silicate and water reducing agent, and the mass ratio is (10-20):(30-40):(10-20):(30-50), and the auxiliary material is cementing material. By selecting plant species, season, land preparation, construction and maintenance management, the present application can provide conditions for slope vegetation restoration, and rapidly improve the vegetation coverage of loose accumulation body slope and gravel soil slope. The slope spraying protective matrix formed by mixing the soil spraying protective agent with soil has the advantages of good anti-seepage and anti-erosion performance, certain mechanical strength, low engineering cost and convenient construction.

Description

Technical Field

[0001] This invention belongs to the field of vegetation restoration and soil and water conservation, specifically relating to an ecological soil spraying agent and its preparation and application. Background Technology

[0002] With the rapid development of infrastructure construction such as highways, railways, water conservancy and hydropower, and the mining industry in my country, a large number of artificial loose deposit slopes and gravel slopes have been generated. Their typical geological characteristics are the destruction of the original soil structure, lack of organic matter and plant roots, low cohesion between particles, weak interconnection, poor erosion resistance, high porosity and high permeability.

[0003] Slope management measures for this type of slope require a comprehensive approach, including retaining walls, drainage, and integrated slope protection. With the rise of ecological civilization construction in recent years, the requirements for ecological sustainability are increasingly stringent while ensuring slope stability. However, most loose deposit slopes and gravelly soil slopes have steep gradients, making ecological protection measures difficult to implement. Vegetation growth is slow, and if heavy rain occurs, large amounts of precipitation infiltrate, causing soil saturation and instability, which can easily lead to surface instability and trigger local or even overall instability, threatening the safety of infrastructure and residential areas downstream of the loose deposit.

[0004] Currently, ecological slope protection technology is being applied to riverbanks, roads, and mine slopes in my country, and the technology is becoming increasingly mature. Common slope restoration techniques mainly involve combining engineering protection, anchor cables, and wire mesh reinforcement with the attachment of vegetation substrates. The primary purpose is to address potential safety hazards and maintain slope stability. Widely used slope treatment methods include thick-layer substrates, high-order aggregates, and vegetation concrete spraying, but most spraying methods require complex processes and are costly.

[0005] Chinese patent CN114524651A discloses a vegetated cementitious soil cementing material capable of regulating pH value, lowering the internal pH of the vegetated cementitious soil, and improving its strength, durability, and vegetation performance. However, it uses L-SAC cement, resulting in high cost. Chinese patent CN110372273A discloses a vegetated cementitious soil ecological restoration substrate and its preparation method, utilizing industrial waste to reduce cement usage and lower production costs. However, the vegetated cementitious soil activator used is expensive, and its compressive strength is low. It is not suitable for loose deposits with steep slopes and high gravel content.

[0006] Therefore, it is crucial to develop a new eco-friendly soil spray agent that can stabilize the existing soil resources of loose deposit slopes, gravel slopes, and other slopes after subsequent improvement, in order to solve the problems of high difficulty and high cost in ecological protection of loose deposit slopes and gravel slopes. Summary of the Invention

[0007] To overcome the problems of complex processes, high costs, insufficient compressive strength and vegetation performance of existing technologies, this invention provides an ecological soil spraying agent, its preparation method and application, which combines economy and protective strength, can quickly restore vegetation on disturbed slopes, and reduce the difficulty of ecological protection of loose deposit slopes and gravelly soil slopes.

[0008] In a first aspect, the present invention provides an eco-friendly soil spraying agent, comprising, by weight parts: 1 to 20 parts of core material and 80 to 100 parts of auxiliary material; The core material is composed of potassium aluminum sulfate, sodium sulfate, sodium silicate and water-reducing agent, with a mass ratio of (10-20):(30-40):(10-20):(30-50); The auxiliary material is a cementing material.

[0009] Preferably, potassium aluminum sulfate in the core material can be replaced by an equal mass of anhydrous copper sulfate.

[0010] Preferably, the optimal mass ratio of the core materials is 16:34:15:35.

[0011] Preferably, the cementing material is a mixture of silicate cement and gypsum in a mass ratio of (80-100):10.

[0012] More preferably, the cementing material is a mixture of silicate cement and gypsum in a mass ratio of 89:10.

[0013] Preferably, the gypsum in the auxiliary material can be replaced by an equal amount of urea. The use of urea in this invention can simultaneously regulate setting time and provide a nitrogen source for the plant.

[0014] Preferably, the eco-friendly soil spray further includes additional materials; the additional materials include neutralizers, fertilizers, and plant fibers.

[0015] Preferably, the neutralizing agent is oxalic acid, and the amount added is determined according to the pH value of the slope spraying substrate formed by mixing the necessary material (i.e., the eco-friendly soil spraying agent of the present invention) and existing soil, and adjusted to a pH of 7 ± 0.5. By adjusting the pH of the slope spraying substrate to the neutral range, an optimal acid-base environment for plant growth can be provided.

[0016] Preferably, the fertilizer can be a commercially available compound fertilizer and / or organic fertilizer. The amount added is determined based on the nutrient content of the slope spraying substrate formed by mixing the necessary materials with the existing soil, ensuring that the substrate contains ≥50 mg / kg of available nitrogen, ≥10 mg / kg of available phosphorus, and ≥80 mg / kg of available potassium to meet the nutrient requirements of the plants in their initial growth stages. Because soil conditions vary greatly in different locations, the nutrient content after mixing will differ significantly. Therefore, it is necessary to monitor the soil nutrient levels and then add fertilizer according to the specific nitrogen, phosphorus, and potassium content.

[0017] Preferably, the plant fiber is selected from one or a combination of wood fiber, crushed rice straw, or crushed stalks, and its amount is 1% to 2% of the total volume of the slope spraying substrate. The slope spraying substrate is a mixture of core materials, auxiliary materials, and existing soil.

[0018] Secondly, the present invention provides a method for preparing the above-mentioned eco-friendly soil spraying agent, comprising the following steps: S1. Place the core materials into a horizontal mixer and stir for 5-10 minutes until they are evenly mixed to obtain the core mixture. S2. Weigh each component of the auxiliary materials according to the proportion, put them into another mixer and stir for 3-5 minutes until they are evenly mixed to obtain the auxiliary mixture; S3. Combine the core mixture from step S1 and the auxiliary mixture from step S2, and continue stirring for 5-8 minutes until evenly mixed to obtain the finished ecological soil spraying agent. The finished product can be stored in bags with a shelf life of 6 months. S4. If additional materials are required, mix the additional materials with the above-mentioned finished products in proportion before use at the construction site.

[0019] Thirdly, the present invention provides the application of the above-mentioned eco-friendly soil spray agent in slope protection.

[0020] Preferably, the application involves mixing the eco-friendly soil spraying agent with existing soil to form a slope spraying matrix, and then using spraying to protect the slope.

[0021] The mass of the ecological soil spraying agent (essential material) shall not exceed 5% of the mass of the slope spraying matrix.

[0022] The existing soil refers to topsoil stripped from local production and construction projects or excavated soil that has undergone soil improvement.

[0023] The existing soil needs to be sieved through a 5mm sieve to remove large-diameter impurities.

[0024] Preferably, the specific method of the application is as follows: (1) Selection of plant species: Local species should be selected, preferably shrubs and herbs with well-developed root systems, drought resistance, and strong adaptability to the environment; (2) Season selection: Since exposed slopes are more prone to soil erosion and affect the slope spraying effect, the slope spraying work should be completed 1 to 2 months before the rainy season, according to the climate characteristics of the application area. Through artificial maintenance, when the rainy season arrives, try to ensure that a certain amount of plant seeds germinate and form a certain coverage. (3) Site preparation: Remove large gravel and garbage from the sprayed slope. Collect dead branches for wood fiber preparation. Make the slope surface as smooth as possible so that the sprayed substrate can be sprayed evenly and fit well with the slope surface.

[0025] (4) Construction: Before construction, calculate the amount of each material to be added based on the area of ​​the sprayed slope. First, mix the core material, auxiliary material and existing soil evenly, then add the additional material and mix. Then, spray the slope according to the conventional slope spraying construction procedure. (5) Maintenance and management: In the early stage of planting, water regularly, sow grass seeds in time, and apply phosphorus and potassium fertilizer as appropriate to areas where vegetation growth is slow and the growth is sluggish, so as to ensure the vegetation restoration effect.

[0026] Compared with the prior art, the present invention has the following beneficial effects: (1) The slope protection matrix formed by mixing the soil spraying agent of the present invention with existing soil has good seepage prevention and erosion resistance. It has a certain mechanical strength and can provide conditions for slope vegetation restoration, which is conducive to rapidly improving the vegetation coverage of loose deposit slopes and gravel slopes.

[0027] (2) The preparation of the soil spraying agent of the present invention does not require any new materials. Its slope spraying application engineering cost is low. The species selected are local suitable species, adapting to local conditions. The soil is sourced locally, which is convenient for construction. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to embodiments. These embodiments are provided to enable those skilled in the art to better understand the technical solutions of the present invention, and are not intended to limit the invention. Unless otherwise specified, the reagents and instruments used in the following embodiments are commercially available.

[0029] During the experiment of this invention, the water-reducing agent was purchased from Shandong Wenhe New Material Co., Ltd., and was FDN-A low-alkali, high-concentration, high-efficiency naphthalene-based water-reducing agent; the fertilizer was high-tower potassium sulfate compound fertilizer containing 45% nitrate nitrogen (15-15-15), purchased from Anhui Hongsifang Fertilizer Co., Ltd.; the silicate cement was Conch Cement P O 42.5R, purchased from Bazhong Conch Cement Co., Ltd.; the plant fiber is 60 mesh wheat straw plant fiber, which can be purchased from Shaanxi Jinhe Agricultural Technology Co., Ltd.; the gypsum is β-type building gypsum powder, which can be purchased from Fengcheng District Lida Gypsum Powder Factory; the urea is superior grade medium granular urea, purchased from Luxi Chemical Group Co., Ltd.

[0030] Table 1. Ingredients and content of Examples 1-5

[0031] The amount of additional materials added in Table 1 was determined based on the actual soil test results on site, which meets the technical requirements of this invention: "adjusting pH to 7±0.5 to meet the nutrient requirements of early plant growth". The thickness of the spraying on site is adjusted according to the slope and soil type (7~10cm). The greater the slope and the coarser the soil particles, the thicker the spraying should be to ensure the protective effect.

[0032] Example 1: An eco-friendly soil spraying agent The components are shown in Table 1, and the specific preparation method is as follows: S1. Preparation of core mixture: Weigh out potassium aluminum sulfate, sodium sulfate, sodium silicate and water reducing agent according to the above ratio, put them into a horizontal mixer, stir at 35 r / min for 8 minutes, mix evenly to obtain core mixture; S2. Preparation of auxiliary mixing agent: Weigh ordinary Portland cement and gypsum according to the above proportions, put them into another horizontal mixer, stir at a speed of 35 r / min for 4 minutes, mix evenly, and obtain auxiliary mixing agent; S3. Finished product preparation: Add all the core mixture obtained in step S1 to the auxiliary mixture in step S2, and continue to stir at a speed of 35 r / min for 7 minutes until it is evenly mixed, thus obtaining the finished product of the ecological soil spraying agent of this embodiment. S4. Finished product storage: Pack the finished product into a moisture-proof woven bag and seal it for storage in a dry and ventilated indoor environment. Shelf life is 6 months.

[0033] Instructions for use on site: Before construction, loose topsoil from the Baihetan Hydropower Station was taken and sieved through a 5mm sieve to remove large-diameter impurities. Materials were weighed according to a 5:95 mass ratio of the ecological soil spraying agent to soil. The spraying agent and sieved soil were first mixed in a drum mixer for 10 minutes until homogeneous. Then, oxalic acid was added to adjust the substrate pH to 7.0, followed by the addition of fertilizer to achieve an effective nitrogen content of 60mg / kg, an effective phosphorus content of 15mg / kg, and an effective potassium content of 100mg / kg. Plant fiber was added until it comprised 1.5% of the total substrate volume, and mixing continued for 5 minutes to obtain the slope spraying substrate. Following standard slope spraying procedures, a wet spraying machine was used to evenly spray the substrate onto the prepared slope surface to a thickness of 8cm.

[0034] Example 2: An eco-friendly soil spray agent The components are shown in Table 1, and the specific preparation method is as follows: S1. Preparation of core mixture: Weigh out potassium aluminum sulfate, sodium sulfate, sodium silicate and water reducing agent according to the above ratio, put them into a horizontal mixer, stir at 35 r / min for 7 minutes, mix evenly to obtain core mixture; S2. Preparation of auxiliary mixing agent: Weigh ordinary Portland cement and gypsum according to the above proportions, put them into another horizontal mixer, stir at a speed of 35 r / min for 3 minutes, mix evenly, and obtain auxiliary mixing agent; S3. Finished product preparation: Add all the core mixture obtained in step S1 to the auxiliary mixture in step S2, and continue to stir at a speed of 35 r / min for 6 minutes until it is evenly mixed, thus obtaining the finished product of the ecological soil spraying agent of this embodiment. S4. Finished product storage: Same as in Example 1.

[0035] The on-site usage method is the same as in Example 1.

[0036] Example 3: An eco-friendly soil spraying agent The components are shown in Table 1, and the specific preparation method is as follows: S1. Preparation of core mixture: Weigh out potassium aluminum sulfate, sodium sulfate, sodium silicate and water-reducing agent according to the above ratio, put them into a horizontal mixer, stir at 35 r / min for 9 minutes, mix evenly to obtain core mixture; S2. Preparation of auxiliary mixing agent: Weigh ordinary silicate cement and gypsum according to the above proportions, put them into another horizontal mixer, stir at a speed of 35 r / min for 5 minutes, mix evenly, and obtain auxiliary mixing agent; S3. Finished product preparation: Add all the core mixture obtained in step S1 to the auxiliary mixture in step S2, and continue to stir at a speed of 35 r / min for 8 minutes until it is evenly mixed, thus obtaining the finished product of the ecological soil spraying agent of this embodiment. S4. Finished product storage: Same as in Example 1.

[0037] Instructions for use on site: Before construction, topsoil from the loose deposits of the Baihetan Hydropower Station (Example 1) was sieved through a 5mm sieve to remove large-diameter impurities, yielding the soil. The materials were weighed according to a spraying agent-to-soil ratio of 4:96. The spraying agent and sieved soil were first placed in a drum mixer and stirred for 12 minutes until homogeneous. Then, oxalic acid was added to adjust the substrate pH to 6.8, and organic fertilizer was added to achieve an effective nitrogen content of 55mg / kg, an effective phosphorus content of 12mg / kg, and an effective potassium content of 90mg / kg. Crushed straw was added until it accounted for 2% of the total substrate volume, and stirring was continued for 6 minutes to obtain the slope spraying substrate. Spraying was carried out according to the conventional slope spraying construction procedure, with a spraying thickness of 10cm.

[0038] Example 4: An eco-friendly soil spray agent The components are shown in Table 1, and the specific preparation method is as follows: S1. Preparation of core mixture: Weigh anhydrous copper sulfate, sodium sulfate, sodium silicate and water-reducing agent according to the above ratio, put them into a horizontal mixer, stir at 35 r / min for 10 minutes, mix evenly to obtain core mixture; S2. Preparation of auxiliary mixing agent: Weigh ordinary Portland cement and urea according to the above ratio, put them into another horizontal mixer, stir at 35 r / min for 4 minutes, mix evenly, and obtain auxiliary mixing agent; S3. Finished product preparation: Add all the core mixture obtained in step S1 to the auxiliary mixture in step S2, and continue to stir at a speed of 35 r / min for 7 minutes until it is evenly mixed, thus obtaining the finished product of the ecological soil spraying agent of this embodiment. S4. Finished product storage: Same as in Example 1.

[0039] Instructions for use on site: Before construction, topsoil stripped from the production project was taken and passed through a 5mm sieve to remove large-diameter impurities, yielding the soil. The materials were weighed according to a spraying agent to soil ratio of 4.5:95.5. The spraying agent and sieved soil were first placed in a drum mixer and mixed for 11 minutes until homogeneous. Then, oxalic acid was added to adjust the substrate pH to 7.2, compound fertilizer was added to achieve an effective nitrogen content of 65mg / kg, an effective phosphorus content of 18mg / kg, and an effective potassium content of 110mg / kg, and crushed straw was added until it accounted for 1.2% of the total substrate volume. Mixing was continued for 5 minutes to obtain the slope spraying substrate. Spraying was carried out according to the conventional slope spraying construction procedure, with a spraying thickness of 9cm.

[0040] Example 5: An Ecological Soil Sprayer The components are shown in Table 1, and the specific preparation method is as follows: S1. Preparation of core mixture: Weigh out potassium aluminum sulfate, sodium sulfate, sodium silicate and water reducing agent according to the above ratio, put them into a horizontal mixer, stir at 35 r / min for 5 minutes, mix evenly to obtain core mixture; S2. Preparation of auxiliary mixing agent: Weigh ordinary silicate cement and urea according to the above ratio, put them into another horizontal mixer, stir at a speed of 35r / min for 3 minutes, mix evenly, and obtain auxiliary mixing agent; S3. Finished product preparation: Add all the core mixture obtained in step S1 to the auxiliary mixture in step S2, and continue to stir at a speed of 35 r / min for 5 minutes until it is evenly mixed to obtain the finished product of the ecological soil spraying agent of this embodiment. S4. Finished product storage: Same as in Example 1.

[0041] Instructions for use on site: Before construction, soil from the gravelly slope was taken and passed through a 5mm sieve to remove large-diameter impurities. The soil was weighed according to a spraying agent to soil ratio of 3:97. The spraying agent and sieved soil were first placed in a drum mixer and mixed for 9 minutes until homogeneous. Then, oxalic acid was added to adjust the substrate pH to 7.0. Mixed fertilizer was added to ensure the substrate had an effective nitrogen content of 70mg / kg, an effective phosphorus content of 20mg / kg, and an effective potassium content of 120mg / kg. Mixed fiber (wood fiber to crushed straw in a 1:1 mass ratio) was added until it accounted for 1.8% of the total substrate volume. Mixing was continued for 4 minutes to obtain the slope spraying substrate. Spraying was carried out according to the standard slope spraying procedure, with a spraying thickness of 7cm.

[0042] Comparative Example 1: An eco-friendly soil spray It is basically the same as Example 2, except that potassium aluminum sulfate is not added and the remainder is made up with silicate cement.

[0043] Comparative Example 2: An eco-friendly soil spray It is basically the same as Example 2, except that potassium aluminum sulfate is replaced with an equal amount of aluminum sulfate.

[0044] Comparative Example 3: An eco-friendly soil spray It is basically the same as Example 2, except that sodium sulfate is not added and the remainder is made up with silicate cement.

[0045] Comparative Example 4: An eco-friendly soil spray It is basically the same as Example 2, except that sodium sulfate is replaced with an equal amount of potassium sulfate.

[0046] Comparative Example 5: An eco-friendly soil spray It is basically the same as Example 2, except that the core material is made of 5 parts by weight of potassium aluminum sulfate, 25 parts by weight of sodium sulfate, 5 parts by weight of sodium silicate, and 25 parts by weight of water reducing agent, while the other components and contents remain unchanged.

[0047] Comparative Example 6: An eco-friendly soil spray It is basically the same as Example 2, except that no gypsum is added and the excess is made up with silicate cement.

[0048] Test Example 1: Unconfined Compressive Strength Test (1) Test objects: 70.7mm×70.7mm×70.7mm cubic spraying matrix test blocks prepared in Examples 1-5 and Comparative Examples 1-6.

[0049] (2) Testing method: Refer to GB / T50107-2010 "Standard for Testing and Evaluation of Concrete Strength" (4.3.1), test the unconfined compressive strength of the test blocks after standard curing for 3d, 7d and 28d respectively. Three parallel test samples are tested in each group, and the arithmetic mean of the results is taken.

[0050] (3) Test data: as shown in Table 2.

[0051] Table 2. Test results of compressive strength of the sprayed substrate for each formulation (unit: MPa)

[0052] As shown in the table above, compared with Example 2, the compressive strength of Comparative Example 1 decreased by 61.1%, 59.4%, and 53.3% at 3d, 7d, and 28d, respectively. The reason is that without potassium aluminum sulfate, it cannot react with sodium silicate to form aluminum silicate gel, the soil particle aggregation is significantly weakened, and the cement hydration products cannot form a continuous cross-linked network, resulting in a significant decrease in the overall mechanical strength of the matrix.

[0053] Among them, the 3d compressive strength of Comparative Example 3 decreased by 55.6%. The reason is that after the absence of sodium sulfate, the early hydration reaction of cement lacked sulfate activators, the hydration rate was significantly slowed down, and the early strength development was seriously insufficient.

[0054] The compressive strength of Comparative Example 5 decreased by more than 60% at all ages. This is because the amount of core material used was lower than the lower limit of this invention, which could not form a complete solidified skeleton. The matrix relied solely on the hydration of cement itself to provide strength, which was insufficient to meet the minimum mechanical requirements for slope protection.

[0055] The 3-day compressive strength of Comparative Example 6 was slightly higher, but the 28-day compressive strength decreased by 13.3%. This is because the cement set too quickly after the gypsum was removed, the hydration products were unevenly distributed, and the internal porosity increased, which limited the later strength development.

[0056] In summary, this application utilizes a synergistic combination of core materials—potassium aluminum sulfate, sodium sulfate, sodium silicate, and a water-reducing agent—along with a cement-gypsum cementing system, effectively improving the early and later compressive strength of the slope spraying substrate. Example 2 demonstrates a 28-day compressive strength of 0.45 N / mm². 2 This meets the mechanical stability requirements of loose aggregate slopes.

[0057] Test Example 2: Seepage Prevention Performance Testing (1) Test objects: Φ100mm×50mm cylindrical spraying matrix test blocks prepared in Examples 1-5 and Comparative Examples 1-6.

[0058] (2) Test method: Refer to the variable head permeability test in GB / T50123-2019 "Standard for Geotechnical Test Methods" to test the permeability coefficient of the test block after standard curing for 28 days. Three parallel test samples are tested in each group, and the arithmetic mean of the results is taken.

[0059] (3) Test data: as shown in Table 3.

[0060] Table 3. Test results of the permeability coefficient of each spray matrix formulation

[0061] As can be seen from the above data, compared with Example 2, the permeability coefficients of Comparative Example 1 and Comparative Example 3 increased by 291 times and 233 times, respectively. The reason is that after the absence of potassium aluminum sulfate or sodium sulfate, the amount of aluminum silicate gel and cement hydration products generated was greatly reduced, and a dense anti-seepage structure could not be formed inside the matrix, and the pore connectivity was significantly enhanced.

[0062] The permeability coefficient of Comparative Example 5 increased by 475 times. This was due to insufficient use of core materials, discontinuous solidification network, and a large number of large pores remaining, which led to the complete failure of the seepage prevention performance.

[0063] The permeability coefficient of Comparative Example 6 increased by 12.5 times. This was because the cement hydration was too fast after the gypsum was missing, resulting in a large number of shrinkage cracks. At the same time, the amount of ettringite crystals generated was insufficient, which could not effectively fill the matrix pores.

[0064] In summary, this invention, through the synergistic effect of the gel filling effect of the core material and the hydration crosslinking effect of the cementitious material, forms a dense, impermeable structure within the matrix, effectively reducing the permeability coefficient, especially in Example 2 where the permeability coefficient is ≤1.2×10⁻⁶. -6 The speed of cm / s can significantly reduce the risk of slope saturation instability caused by rainwater infiltration.

[0065] Experiment Example 3: Vegetation Coverage Test (1) Test objects: Slope vegetation of the experimental plot (5m×10m) of Haizigou spoil disposal site of Baihetan Hydropower Station in Examples 1-5 and Comparative Examples 1-6.

[0066] (2) Detection method: The vegetation coverage and average plant height of each plot were measured at 3 months, 6 months and 12 months after spraying using the 1m×1m sampling method. Five quadrats were set up in each plot, and the arithmetic mean of the results was taken. The test plants were the local suitable species Bermuda grass + Amorpha fruticosa (mixed sowing quality ratio 7:3).

[0067] (3) Test data: as shown in Table 4.

[0068] Table 4. Results of vegetation growth monitoring for each sprayed substrate formulation.

[0069] As can be seen from the above data, compared with Example 2, the vegetation coverage of Comparative Example 1 and Comparative Example 3 decreased by 31.6% and 34.7% respectively over 12 months. The reason is that the substrate mechanical strength and impermeability are insufficient, the soil loss is serious after heavy rain, the plant roots cannot take root stably, and nutrients are lost in large quantities with runoff, resulting in slow vegetation growth.

[0070] In Comparative Example 5, vegetation cover decreased by 41.1% over 12 months. This was because the substrate could not be solidified at all, soil erosion was severe, most grass seeds were washed away by rainwater, and vegetation was difficult to establish.

[0071] In Comparative Example 2, vegetation cover decreased by 8.4% over 12 months. This was because after aluminum sulfate replaced potassium aluminum sulfate, the substrate lacked potassium supply, which restricted plant growth in the later stages. At the same time, the soil aggregation effect was weakened, and the root anchorage ability decreased.

[0072] In summary, this invention achieves multi-dimensional synergy between soil solidification, nutrient retention, and plant growth. Potassium aluminum sulfate not only provides flocculation and solidification but also supplements the potassium element essential for plants. Combined with the nitrogen source supply of urea, it effectively improves vegetation coverage and growth rate, achieving a coverage of over 90% within 12 months, which is significantly superior to traditional ecological slope protection technology.

[0073] Test Example 4: Scour Resistance Test (1) Test objects: 100cm×100cm×5cm slope spraying matrix samples prepared in Examples 1~5 and Comparative Examples 1~6, with a slope of 30°.

[0074] (2) Testing method: Artificial simulated rainfall test was adopted, the rainfall intensity was set to 120 mm / h, the rainfall duration was 60 min, the soil loss of each sample after rainfall was measured, the soil loss per unit area of ​​a single rainstorm was calculated, 3 parallel samples were tested in each group, and the arithmetic mean of the results was taken.

[0075] (3) Test data: as shown in Table 5.

[0076] Table 5. Test results of erosion resistance of each spray coating matrix formulation.

[0077] As can be seen from the above data, compared with Example 2, the soil loss per unit area of ​​Comparative Example 1 and Comparative Example 3 increased by 9.2 times and 9.8 times, respectively. The reason is that after the core component is missing, the soil particles cannot effectively aggregate, the matrix surface has poor resistance to water flow shearing, and the soil is stripped off under the scouring of heavy rain.

[0078] The soil erosion modulus of Comparative Example 5 increased by 13.9 times. This was because the amount of core material used was insufficient, the matrix had no obvious solidification effect, and it was basically equivalent to bare soil with weak erosion resistance.

[0079] The soil erosion modulus of Comparative Example 6 increased by 2.36 times. This was because the absence of gypsum resulted in a large number of shrinkage cracks on the matrix surface, which allowed water to easily seep into the cracks and erode the internal soil, leading to increased erosion.

[0080] In summary, this invention significantly enhances the resistance of the matrix surface to water flow shear through the synergistic effect of the flocculation and agglomeration of the core material and the surface solidification of the cementitious material. The soil erosion modulus in Example 2 is only 210 t / (km²). a) This is far below the allowable soil erosion modulus in Southwest China (500 t / (km²)). a)) possesses excellent erosion resistance.

[0081] Application examples ① Application Subject: A typical loose sediment slope was selected for testing and demonstration at the Haizigou spoil heap of the Baihetan Hydropower Station. Three plots (5m × 10m) were set up along the slope. Comparative tests were conducted using conventional backfilling with soil and vegetated cement-soil (a construction method, see NB / T 10490-2021 "Technical Specification for Vegetated Cement-Soil Habitat Construction on Hydropower Project Slopes"). The organic fertilizer used in the tests was a highly active organic fertilizer, available from Hebei Danong Fertilizer Co., Ltd.

[0082] ②The soil spraying agent formula is shown in Table 6.

[0083] Table 6. Proportioning Table of Ecological Soil Spraying Agent in Example 2 of the Invention

[0084] ③Application effect: In March and April 2021, comparative test construction was completed. After two annual cycles of observation from 2021 to 2023, the vegetation coverage of the plots sprayed with the ecological soil spraying agent of this invention was 10.4% and 18.7% higher than that of the backfilled and vegetated cement-soil slopes, respectively; the soil erosion modulus was 26.3% and 5.1% lower than that of the backfilled and vegetated cement-soil slopes, respectively.

[0085] Table 7 Comparison of the application effects of this invention on vegetated cement-soil and backfilling.

[0086] The above observation period is uniformly from March 2021 to March 2023, a total of 24 months, covering two rainy seasons, and the data is representative.

[0087] In addition, the construction cost of this invention is slightly higher than that of backfilling with soil, but about 12% lower than that of vegetated cement soil.

[0088] In summary, the eco-friendly soil spray agent of this invention effectively improves slope protection performance through a dual synergistic system. The four components—potassium aluminum sulfate, anhydrous copper sulfate, sodium sulfate, sodium silicate, and water-reducing agent—work together to accelerate the curing reaction and optimize the curing structure. The gel network of the core materials cross-links with the cement-gypsum / urea cementitious system. Simultaneously, the gypsum / urea system combines the functions of regulating setting, preventing seepage, and supplying nutrients, resolving the contradiction between strength and vegetation performance in traditional ecological slope protection technologies. While ensuring slope mechanical stability and erosion resistance, it significantly improves vegetation recovery speed, providing an economical and efficient solution for the ecological protection of loose sediment slopes and gravelly soil slopes.

Claims

1. An eco-friendly soil spraying agent, characterized in that, By mass, it contains 1-20 parts of core material and 80-100 parts of auxiliary material. The core material consists of potassium aluminum sulfate, sodium sulfate, sodium silicate and water-reducing agent in a mass ratio of 10-20:30-40:10-20:30-50. The auxiliary material is a cementitious material.

2. The ecological soil spraying agent according to claim 1, characterized in that, Potassium aluminum sulfate in the core material can be replaced with anhydrous copper sulfate.

3. The ecological soil spraying agent according to claim 1, characterized in that, The cementing material is a mixture of silicate cement and gypsum in a mass ratio of 80 to 100:

10.

4. The eco-friendly soil spraying agent according to claim 3, characterized in that, The cementing material is a mixture of silicate cement and gypsum in a mass ratio of 89:

10.

5. The eco-friendly soil spraying agent according to claim 3, characterized in that, The gypsum can be replaced with urea.

6. The eco-friendly soil spraying agent according to claim 1, characterized in that, It also includes additional materials, such as neutralizers, fertilizers, and plant fibers.

7. The eco-friendly soil spraying agent according to claim 1, characterized in that, The neutralizing agent is oxalic acid.

8. The eco-friendly soil spraying agent according to claim 1, characterized in that, The plant fiber is selected from one or a combination of several of wood fiber, rice straw or stalk.

9. The application of the eco-friendly soil spraying agent as described in any one of claims 1 to 8 in slope protection.

10. The application as described in claim 9, characterized in that, The specific process of the application is as follows: the ecological soil spraying agent is mixed with the existing soil to form a slope spraying matrix, and the slope is protected by spraying; the ecological soil spraying agent accounts for no more than 5% of the mass of the slope spraying matrix; the existing soil is the topsoil stripped from the construction of the local production project or the excavated soil that has been improved; the existing soil needs to be sieved through a 5mm sieve to remove large-diameter impurities.

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