A substrate material for ecological restoration of slopes in western Sichuan Plateau and its preparation method

Abstract

This invention discloses a slope ecological restoration matrix material and its preparation method for use in the western Sichuan plateau, belonging to the field of slope ecological restoration technology. The slope ecological restoration matrix material for the western Sichuan plateau, by weight, comprises the following components: 80-100 parts planting soil, 8-15 parts self-made modified diatomaceous earth, 4-8 parts biochar, 10-18 parts organic fertilizer, 2-5 parts cement, 0.3-1.5 parts nano-silica, 0.5-1.5 parts wood fiber, 1.0-3.0 parts self-made modified polypropylene fiber, 1.5-3.5 parts slow-release compound fertilizer, 0.3-0.8 parts sodium carboxymethyl cellulose, and 35-50 parts water. In the ecological matrix material of this application, the incorporation of self-made modified diatomaceous earth and self-made modified polypropylene fiber can achieve a combination of uniform dispersion and surface roughening to realize strong physical anchoring, which can effectively resist the impact of rainwater and the erosion of runoff, reduce soil erosion, and thus have excellent rainwater erosion resistance, effectively protect the slope surface, and promote the rapid establishment and stable growth of vegetation.

Description

Technical Field

[0001] This invention belongs to the field of slope ecological restoration technology, specifically, it relates to a slope ecological restoration matrix material and its preparation method for use in the western Sichuan plateau. Background Technology

[0002] my country's rapid economic development has been accompanied by a year-on-year increase in various infrastructure construction projects. The construction of linear projects such as highways and railways often involves the excavation of large areas of mountains. Due to the varying terrain across my country and the requirements of route planning, these infrastructure projects typically involve deep excavation of road cuts and high embankment construction, resulting in numerous exposed slopes. This damages the original vegetation cover, creating numerous exposed wound surfaces and engineering slopes, which are highly susceptible to slope collapses, landslides, and debris flows. It also causes soil erosion, water loss, and shallow localized landslides, leading to ecological damage. This problem is particularly prominent and severe in the western Sichuan Plateau region. The western Sichuan Plateau is characterized by high altitude, cold climate, and significant vertical variations; long, cold winters and short, cool summers; abundant sunshine; concentrated rainfall; and distinct dry and rainy seasons. It features high altitude, deep valleys, steep terrain, large slopes, active geological structures, and fractured rock masses. Furthermore, the western Sichuan Plateau has harsh climatic conditions, with huge diurnal temperature variations, distinct dry and wet seasons, concentrated heavy rainfall, and frequent freeze-thaw cycles. These factors combined result in poorer slope stability, more severe soil erosion, and extremely weak ecological restoration capacity in the western Sichuan plateau region, posing significant challenges to both natural vegetation succession and artificial restoration. However, by greening the slopes, it is possible to stabilize them while restoring vegetation and beautifying the surrounding environment.

[0003] Existing technologies include slope ecological restoration technologies, such as Chinese invention patent application number CN201711211112.1, which discloses a greening method suitable for steep mudstone and shale slopes. This method includes the following steps: spraying a substrate mixture into a horizontal ditch twice; spraying the substrate mixture once to a depth of 1-2 cm from the top of the ditch; and spraying a substrate mixture containing plant seeds a second time to fill the ditch. The substrate mixtures used in both sprayings are identical, comprising greening substrate, planting soil, and straw fiber. The weight ratio of the greening substrate, planting soil, and straw fiber is 3:12-4:1. The greening substrate includes organic matter, compound fertilizer, superabsorbent resin, polyacrylamide, cyanoacrylate binder, fly ash, and dazomet.

[0004] The aforementioned existing technology uses straw fiber as a modifier for slope greening. However, in actual use, straw fiber significantly reduces the shear strength of the substrate. This is because straw fiber has a thin, sheet-like structure. When straw is incorporated into the substrate, the overlapping of these sheets loosens the originally dense planting soil structure, creating voids. This prevents the substrate from effectively binding and reinforcing the soil, making it prone to deformation under shear stress, thus reducing its shear strength. Slope soil is susceptible to sliding and collapse under its own weight. To maintain slope stability, it is necessary to increase shear strength. Furthermore, if the soil has a low density and light weight, it is less prone to sliding and collapse on the slope.

[0005] Although the aforementioned existing technologies use water-absorbing resins and binders to effectively improve the water retention performance of ecological restoration matrix materials and form a granular structure that is conducive to plant growth, there is still a huge room for improvement in their ability to resist rainwater erosion and shear on slopes. Summary of the Invention

[0006] To address the deficiencies in the aforementioned technical solutions, the present invention aims to provide a slope ecological restoration substrate material and its preparation method for the Sichuan-Western Plateau. This objective can be achieved through the following technical solution: A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following components: 80-100 parts planting soil, 8-15 parts self-made modified diatomaceous earth, 4-8 parts biochar, 10-18 parts organic fertilizer, 2-5 parts cement, 0.3-1.5 parts nano-silica, 0.5-1.5 parts wood fiber, 1.0-3.0 parts self-made modified polypropylene fiber, 1.5-3.5 parts slow-release compound fertilizer, 0.3-0.8 parts sodium carboxymethyl cellulose, and 35-50 parts water.

[0007] The planting soil is typical arable land soil, collected by a five-point sampling method. After removing the topsoil, it is mixed evenly, with a particle size of less than 1 cm and a moisture content of less than 25%.

[0008] The biochar is one of peanut shell biochar and rice husk biochar; it was purchased from Henan Lize Environmental Protection Technology Co., Ltd.

[0009] The organic fertilizer is one of fermented cow manure, fermented sheep manure, or fermented chicken manure; it was purchased from Shijiazhuang Wofuwo Fertilizer Co., Ltd.

[0010] The cement is P.042.5 grade ordinary Portland cement;

[0011] The wood fibers have a high length-to-width ratio, a length of about 1-3 mm, and are sourced from Shandong Daitian Engineering Materials.

[0012] The nano-silica was purchased from Hubei Topband Chemical Co., Ltd., with product number TB14662.

[0013] The slow-release compound fertilizer is composed of polyurethane-coated urea, potassium sulfate, and ammonium dihydrogen phosphate in a mass ratio of 1:1:1. The polyurethane-coated urea is purchased from Jinan Xiangchunyuan Chemical Technology Co., Ltd.; the potassium sulfate is purchased from Zhengzhou Jiajie Chemical Products Co., Ltd.; and the ammonium dihydrogen phosphate is purchased from Shandong Suian Chemical Co., Ltd.

[0014] The preparation method of the self-made modified diatomaceous earth is as follows: Aminated diatomaceous earth is placed in DMF and ultrasonically dispersed for 15 min to form a suspension dispersion; polybutylene itaconic acid is added to DMF and stirred until completely dissolved to form a polybutylene itaconic acid solution; under inert gas protection, the polybutylene itaconic acid solution is slowly added dropwise to the suspension dispersion while stirring. During continuous stirring, the temperature of the reaction system is raised to 100 degrees Celsius, stirring is maintained, and the reaction is continued for 12 h; after the reaction is completed, heating is stopped, and the reaction system is allowed to cool naturally to room temperature; the solid product is separated by filtration and washed three times with anhydrous ethanol to remove unreacted substances; then the product is placed in a vacuum drying oven and dried to constant weight to obtain the self-made modified diatomaceous earth.

[0015] The preparation method of the aminated diatomaceous earth is as follows: Diatomaceous earth is placed in a beaker, soaked in HCl solution for 1 hour, then thoroughly washed with ultrapure water until neutral, and finally dried under vacuum at 60 degrees Celsius for 12 hours. The HCl-treated diatomaceous earth particles are mixed into an ethanol solution containing APTES, and the mixture is sonicated for 30 minutes to obtain a uniformly dispersed suspension. The suspension is stirred at 60 degrees Celsius for 8 hours to ensure complete amination. The product is collected by centrifugation and washed several times with ethanol and deionized water. The resulting product is dried under vacuum at 60 degrees Celsius for 12 hours to prepare the aminated diatomaceous earth.

[0016] Preparation method of self-made modified polypropylene fiber: Maleic anhydride grafted polypropylene fiber was placed in a reaction vessel, xylene was added, the reaction vessel was sealed, and the reaction vessel was shaken at room temperature for 2 hours. After shaking, a dispersion of branched polyethyleneimine and a dispersion of dicyclohexylcarbodiimine were added in sequence. The temperature was then raised to 45 degrees Celsius, and the reaction was continued to be shaken for 8 hours. After the reaction was completed, the reaction solution was filtered out, and the fiber was recovered. The fiber was washed twice with acetone, then washed twice with deionized water, and finally dried in a vacuum oven at 60 degrees Celsius to constant weight to obtain the self-made modified polypropylene fiber.

[0017] The preparation methods of the branched polyethyleneimine dispersion and the dicyclohexylcarbodiimine dispersion are as follows: take one beaker and disperse 1g of branched polyethyleneimine in 30ml of xylene, and take another beaker and disperse 0.9g of dicyclohexylcarbodiimine in 20ml of xylene.

[0018] The branched polyethyleneimine has a number-average molecular weight of 600-1500.

[0019] The preparation method of maleic anhydride-grafted polypropylene fiber is as follows: Nitrogen gas is introduced into a three-necked flask and maintained in a nitrogen atmosphere. Then, polypropylene fiber, xylene, maleic anhydride, and thermal initiator benzoyl peroxide are added. The mixture is stirred and heated to 50 degrees Celsius, held for 45 minutes, and then rapidly heated to 90 degrees Celsius. The mixture is stirred at 90 degrees Celsius for 3-4 hours. The polypropylene fiber is then transferred to a Soxhlet extractor and extracted with acetone for 12 hours to remove unreacted products. Finally, the purified product is dried in a vacuum oven at 60 degrees Celsius to constant weight to obtain maleic anhydride-grafted polypropylene fiber.

[0020] A method for preparing a slope ecological restoration matrix material for the Sichuan-Western Plateau: Planting soil, self-made modified diatomaceous earth, biochar, cement, nano-silica, wood fiber, and self-made modified polypropylene fiber are added sequentially to a mixer according to the mass ratio, and stirred evenly for 3-5 minutes. After thorough mixing, organic fertilizer, slow-release compound fertilizer, and sodium carboxymethyl cellulose are added, and stirring continues for 3-5 minutes. Finally, water is added according to the ratio, and the mixture is stirred evenly for 5-8 minutes to obtain a slope ecological restoration matrix material for the Sichuan-Western Plateau.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. This application introduces amination and grafting treatments into diatomaceous earth, successfully grafting polybutylene itaconic acid (PBEA) chains onto the surface of the self-made modified diatomaceous earth, forming a core-shell composite with a network structure. This structure not only endows the self-made modified diatomaceous earth with more active terminal hydroxyl groups and double bonds, providing more active cross-linking points and enhancing its reactivity and free volume, but also forms strong chemical bonds between the diatomaceous earth and PBEA chains, stronger than the intermolecular forces of PBEA. Therefore, when the ecological matrix material is subjected to stress and deformation, the self-made modified diatomaceous earth in this application can exert a significant stress release and bridging effect, effectively dispersing stress, preventing crack propagation, and ensuring the structural integrity of the matrix material under environmental changes such as dryness and swelling. Furthermore, the diatomaceous earth is relatively lightweight, ensuring stability under slopes in the western Sichuan plateau.

[0023] 2. The self-made modified polypropylene fiber in this application is first grafted with maleic anhydride and then subjected to a secondary acylation reaction with branched polyethyleneimine. The branched polyethyleneimine has a polyamine structure, which introduces a large number of amine groups on the surface of the polypropylene fiber and forms a more complex branched structure. This significantly increases the number of convex peaks and concave valleys on the fiber surface of the self-made modified polypropylene fiber, resulting in a significant increase in its specific surface area and roughness. This not only greatly enhances the hydrophilicity of the fiber, which is conducive to its uniform dispersion in the ecological matrix, but also strengthens the physical embedding and interfacial bonding between the fiber and the matrix, thereby giving the ecological matrix material higher cohesion and resistance to shear failure.

[0024] 3. In the ecological matrix material of this application, the self-made modified diatomaceous earth can endow the matrix material with micro-stress dispersion and bridging ability. Combined with the strong physical anchoring achieved by the self-made modified polypropylene fiber in the matrix due to the uniform dispersion and surface roughening caused by the improved hydrophilicity, the two work together to not only improve the overall mechanical strength and crack resistance of the matrix material, but also make the internal structure of the matrix material more compact and the pore distribution more reasonable. This tough and stable structure can effectively resist the impact of rainwater and the erosion of runoff, reduce soil erosion, and thus have excellent rainwater erosion resistance. It can effectively protect the slope surface and promote the rapid establishment and stable growth of vegetation. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. Furthermore, regarding numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] In the following examples, "parts" refers to parts by weight.

[0030] Example 1

[0031] A slope ecological restoration matrix material for the Sichuan-Western Plateau and its preparation method, comprising the following components by weight: 80 parts planting soil, 8 parts self-made modified diatomaceous earth, 4 parts biochar, 10 parts organic fertilizer, 2 parts cement, 0.3 parts nano silica, 0.5 parts wood fiber, 1.0 part self-made modified polypropylene fiber, 1.5 parts slow-release compound fertilizer, 0.3 parts sodium carboxymethyl cellulose, and 35 parts water;

[0032] The planting soil is typical arable land soil, collected by a five-point sampling method. After removing the topsoil, it is mixed evenly, with a particle size of less than 1 cm and a moisture content of less than 25%.

[0033] The biochar is peanut shell biochar;

[0034] The organic fertilizer is fermented sheep manure;

[0035] The cement is P.042.5 grade ordinary Portland cement;

[0036] The preparation method of the aminated diatomaceous earth is as follows: 6g of diatomaceous earth is weighed and placed in a 100mL beaker, and soaked in a 2mol / L HCl solution for 1h to ensure that the hydroxyl groups on the surface of the diatomaceous earth are fully activated. Then, the treated diatomaceous earth particles are thoroughly washed with ultrapure water until neutral, and finally dried under vacuum at 60°C for 12h. 3g of HCl-treated diatomaceous earth particles are weighed and mixed into a 100mL ethanol solution containing 3mL of APTES. The mixture is ultrasonically treated for 30min to obtain a uniformly dispersed suspension. The suspension is stirred at 60°C for 8h to ensure that the amination reaction is complete. The product is collected by centrifugation and washed several times with ethanol and deionized water, respectively. The obtained product is dried under vacuum at 60°C for 12h to prepare the aminated diatomaceous earth.

[0037] The preparation method of the self-made modified diatomaceous earth is as follows: 10g of aminated diatomaceous earth is placed in 100ml of DMF and ultrasonically dispersed for 15min to form a suspension; 2g of polybutylene itaconic acid is added to 20ml of DMF and stirred until completely dissolved to form a polybutylene itaconic acid solution. Under inert gas protection, the polybutylene itaconic acid solution is slowly added dropwise to the suspension while stirring. During continuous stirring, the temperature of the reaction system is raised to 100 degrees Celsius, stirring is maintained, and the reaction is continued for 12h; after the reaction is completed, heating is stopped, and the reaction system is allowed to cool naturally to room temperature; then the solid product is separated by vacuum filtration and washed three times with anhydrous ethanol to remove unreacted substances. The product is then placed in a vacuum drying oven and dried to constant weight to obtain the self-made modified diatomaceous earth.

[0038] The preparation method of the poly(itaconic acid) butylene glycol ester is as follows: 13g of itaconic acid, 18g of 1,4-butanediol, 0.15g of stannous chloride, and 0.02g of hydroquinone are added to a four-necked flask; stirring is started, nitrogen gas is introduced, and the temperature is slowly raised to about 150 degrees Celsius. The reaction continues at this temperature until the acid value decreases significantly and remains constant, indicating that most of the carboxyl groups of itaconic acid have been consumed; then, maintaining the temperature at 150 degrees Celsius, another 26g of itaconic acid is slowly added, and the reaction continues until the acid value shows a significant decrease. After the temperature drops and remains constant, 18g of 1,4-butanediol is slowly added at 150°C. The reaction continues at 150°C, and the generated water is removed. When all monomers have been added and the acid value is measured to be below 40mg(KOH) / g, the temperature is raised to about 180°C, and the system pressure is gradually reduced to a negative pressure of 0.1MPa. The reaction continues for 4 hours. After the reaction is completed, the temperature is lowered under nitrogen protection to obtain the product poly(butylene itaconic acid).

[0039] The preparation method of maleic anhydride-grafted polypropylene fiber is as follows: Nitrogen gas is introduced into a three-necked flask and maintained in a nitrogen atmosphere. Then, 10g of polypropylene fiber, 3g of xylene, 1g of maleic anhydride, and 0.3g of thermal initiator benzoyl peroxide are added. The mixture is stirred and heated to 50°C and maintained for 45 minutes to allow the polypropylene fiber to fully swell. Then, the temperature is rapidly increased to 90°C and stirred at 90°C for 3-4 hours. The polypropylene fiber is then transferred to a Soxhlet extractor and extracted with acetone for 12 hours to remove unreacted products. Finally, the purified product is dried in a vacuum oven at 60°C to constant weight to obtain maleic anhydride-grafted polypropylene fiber.

[0040] Preparation method of self-made modified polypropylene fiber: Maleic anhydride-grafted polypropylene fiber was placed in a reaction vessel, and 50 ml of xylene was added. The reaction vessel was sealed and shaken at room temperature for 2 hours to allow the maleic anhydride-grafted polypropylene fiber to swell fully. After shaking, a dispersion of branched polyethyleneimine and a dispersion of dicyclohexylcarbodiimine were added sequentially. The temperature was then raised to 45 degrees Celsius, and the reaction was continued to be shaken for 8 hours. After the reaction was completed, the reaction solution was filtered out, and the fiber was recovered. The fiber was washed twice with acetone, then twice with deionized water, and finally dried in a vacuum oven at 60°C to constant weight to obtain the self-made modified polypropylene fiber.

[0041] The preparation methods of the branched polyethyleneimine dispersion and the dicyclohexylcarbodiimine dispersion are as follows: take one beaker and disperse 1g of branched polyethyleneimine in 30ml of xylene, and take another beaker and disperse 0.9g of dicyclohexylcarbodiimine in 20ml of xylene.

[0042] The branched polyethyleneimine has a number-average molecular weight of 600-1500.

[0043] A method for preparing a slope ecological restoration matrix material for the Sichuan-Western Plateau: Planting soil, self-made modified diatomaceous earth, biochar, cement, nano-silica, wood fiber, and self-made modified polypropylene fiber are added sequentially to a mixer according to the mass ratio, and stirred evenly for 3-5 minutes. After thorough mixing, organic fertilizer, slow-release compound fertilizer, and sodium carboxymethyl cellulose are added, and stirring continues for 3-5 minutes. Finally, water is added according to the ratio, and the mixture is stirred evenly for 5-8 minutes to obtain a slope ecological restoration matrix material for the Sichuan-Western Plateau.

[0044] Example 2

[0045] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following: 84 parts planting soil, 9 parts self-made modified diatomaceous earth, 5 parts biochar, 11.5 parts organic fertilizer, 2.5 parts cement, 0.5 parts nano silica, 0.7 parts wood fiber, 1.4 parts self-made modified polypropylene fiber, 2.0 parts slow-release compound fertilizer, 0.4 parts sodium carboxymethyl cellulose, and 38 parts water.

[0046] The biochar is peanut shell biochar;

[0047] The organic fertilizer is fermented cow manure;

[0048] In Example 2, the preparation methods of the self-made modified diatomaceous earth, the self-made modified polypropylene fiber, and the ecological substrate material for slope greening are all the same as those in Example 1.

[0049] Example 3

[0050] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following: 88 parts planting soil, 10 parts self-made modified diatomaceous earth, 6 parts biochar, 13 parts organic fertilizer, 3 parts cement, 0.7 parts nano silica, 0.9 parts wood fiber, 1.8 parts self-made modified polypropylene fiber, 2.5 parts slow-release compound fertilizer, 0.5 parts sodium carboxymethyl cellulose, and 42 parts water.

[0051] The biochar is peanut shell biochar;

[0052] The organic fertilizer is fermented sheep manure;

[0053] In Example 3, the preparation methods of the self-made modified diatomaceous earth, the self-made modified polypropylene fiber, and the ecological substrate material for slope greening are all the same as those in Example 1.

[0054] Example 4

[0055] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following: 92 parts planting soil, 12 parts self-made modified diatomaceous earth, 7 parts biochar, 15 parts organic fertilizer, 3.8 parts cement, 1.0 part nano-silica, 1.1 parts wood fiber, 2.2 parts self-made modified polypropylene fiber, 3.0 parts slow-release compound fertilizer, 0.6 parts sodium carboxymethyl cellulose, and 45 parts water.

[0056] The biochar is rice husk biochar.

[0057] The organic fertilizer is fermented chicken manure;

[0058] In Example 4, the preparation methods for the self-made modified diatomaceous earth, the self-made modified polypropylene fiber, and the ecological substrate material for slope greening are all the same as those in Example 1.

[0059] Example 5

[0060] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following: 96 parts planting soil, 14 parts self-made modified diatomaceous earth, 7.5 parts biochar, 17 parts organic fertilizer, 4.5 parts cement, 1.3 parts nano-silica, 1.3 parts wood fiber, 2.6 parts self-made modified polypropylene fiber, 3.3 parts slow-release compound fertilizer, 0.7 parts sodium carboxymethyl cellulose, and 48 parts water.

[0061] The biochar is rice husk biochar.

[0062] The organic fertilizer is fermented sheep manure;

[0063] In Example 5, the preparation methods for the self-made modified diatomaceous earth, the self-made modified polypropylene fiber, and the ecological substrate material for slope greening are all the same as those in Example 1.

[0064] Example 6

[0065] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following components: 100 parts planting soil, 15 parts self-made modified diatomaceous earth, 8 parts biochar, 18 parts organic fertilizer, 5 parts cement, 1.5 parts nano silica, 1.5 parts wood fiber, 3.0 parts self-made modified polypropylene fiber, 3.5 parts slow-release compound fertilizer, 0.8 parts sodium carboxymethyl cellulose, and 50 parts water.

[0066] The biochar is rice husk biochar.

[0067] The organic fertilizer is fermented sheep manure;

[0068] In Example 6, the preparation methods for the self-made modified diatomaceous earth, the self-made modified polypropylene fiber, and the ecological substrate material for slope greening are all the same as those in Example 1.

[0069] Comparative Example 1

[0070] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following components: 96 parts planting soil, 14 parts diatomaceous earth, 7.5 parts biochar, 17 parts organic fertilizer, 4.5 parts cement, 1.3 parts nano silica, 1.3 parts wood fiber, 2.6 parts polypropylene fiber, 3.3 parts slow-release compound fertilizer, 0.7 parts sodium carboxymethyl cellulose, and 48 parts water.

[0071] Comparative Example 1 is based on Example 5, except that the modification of diatomaceous earth was omitted and commercially available diatomaceous earth was added directly; the modification of polypropylene fiber was omitted and commercially available polypropylene fiber was added directly.

[0072] In Comparative Example 1, the preparation method of the ecological substrate material for slope greening and planting is the same as that in Example 5.

[0073] Comparative Example 2

[0074] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following components: 96 parts planting soil, 14 parts self-made modified diatomaceous earth, 7.5 parts biochar, 17 parts organic fertilizer, 4.5 parts cement, 1.3 parts nano silica, 1.3 parts wood fiber, 2.6 parts polypropylene fiber, 3.3 parts slow-release compound fertilizer, 0.7 parts sodium carboxymethyl cellulose, and 48 parts water.

[0075] Comparative Example 2 is based on Example 5, except that the modification of polypropylene fibers was omitted, and commercially available polypropylene fibers were added directly.

[0076] In Comparative Example 2, the preparation methods of the self-made modified diatomaceous earth and the preparation methods of the ecological substrate materials for slope greening and planting are the same as those in Example 5.

[0077] Comparative Example 3

[0078] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following components: 96 parts planting soil, 14 parts diatomaceous earth, 7.5 parts biochar, 17 parts organic fertilizer, 4.5 parts cement, 1.3 parts nano silica, 1.3 parts wood fiber, 2.6 parts self-made modified polypropylene fiber, 3.3 parts slow-release compound fertilizer, 0.7 parts sodium carboxymethyl cellulose, and 48 parts water.

[0079] Comparative Example 3 is based on Example 5, except that the modification of diatomaceous earth is omitted, and commercially available diatomaceous earth is added directly.

[0080] In Comparative Example 3, the preparation methods of the self-made modified polypropylene fiber and the preparation methods of the ecological substrate material for slope greening and planting are the same as those in Example 5.

[0081] Comparative Example 4

[0082] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following components: 96 parts planting soil, 14 parts aminated diatomaceous earth, 7.5 parts biochar, 17 parts organic fertilizer, 4.5 parts cement, 1.3 parts nano silica, 1.3 parts wood fiber, 2.6 parts self-made modified polypropylene fiber, 3.3 parts slow-release compound fertilizer, 0.7 parts sodium carboxymethyl cellulose, and 48 parts water.

[0083] Comparative Example 4 is based on Example 5, except that only the diatomaceous earth was pretreated, that is, the pretreated aminated diatomaceous earth was directly added to the ecological substrate material for slope greening and planting.

[0084] In Comparative Example 4, the preparation methods of the self-made modified polypropylene fiber and the preparation methods of the ecological substrate material for slope greening and planting are the same as those in Example 5.

[0085] Comparative Example 5

[0086] A slope ecological restoration substrate material for the Sichuan-Western Plateau, by weight, comprises the following components: 96 parts planting soil, 14 parts self-made modified diatomaceous earth, 7.5 parts biochar, 17 parts organic fertilizer, 4.5 parts cement, 1.3 parts nano silica, 1.3 parts wood fiber, 2.6 parts maleic anhydride grafted polypropylene fiber, 3.3 parts slow-release compound fertilizer, 0.7 parts sodium carboxymethyl cellulose, and 48 parts water.

[0087] Comparative Example 5 is based on Example 5, except that the self-made modified polypropylene fiber is replaced with maleic anhydride-grafted polypropylene fiber and directly added to the ecological substrate material for slope greening and planting.

[0088] In Comparative Example 5, the preparation methods of the self-made modified diatomaceous earth and the preparation methods of the ecological substrate materials for slope greening and planting are the same as those in Example 5.

[0089] Test case

[0090] The ecological matrix materials prepared in Examples 1-6 and Comparative Examples 1-5 were placed into a ring die with a height of 20 mm and an inner diameter of 61.8 mm. After compaction, the resulting ecological matrix material ring die samples were sealed with plastic film and then placed in a constant temperature and humidity curing chamber with a relative humidity of over 90% and a temperature maintained at 25°C. After curing for 7 days, the plastic film was removed to obtain the substrate samples. The shear strength and cracking effect of the ecological matrix materials in Examples 1-6 and Comparative Examples 1-5 were then tested.

[0091] Shear strength test: The shear strength of the specimens in Examples 1-6 and Comparative Examples 1-5 was tested using a triple direct shear apparatus for unsaturated soil, model HC-UDR-300. The axial loading speed of the apparatus was set to 1 mm / min, the normal stress was set to 100 kPa, 200 kPa and 300 kPa, and the shear rate was set to 0.8 mm / min. After the test was completed, the cohesion and internal friction angle data of the specimens were collected.

[0092] Cracking effect test of ecological matrix material: After ten dry and wet cycles, the cracking of Examples 1-6 and Comparative Examples 1-5 was observed by taking pictures, and the length and area of ​​the cracks were calculated by ImageJ software.

[0093] The first dry-wet cycle is a drying cycle of 24 hours, during which the moisture content of the sample is close to 0, and a moisture absorption cycle of 12 hours, during which the sample is close to saturated with water.

[0094] Scour resistance coefficient test: The ecological substrate materials for slope greening planting in Examples 1-6 and Comparative Examples 1-5 were prepared into a base slurry and then sprayed onto the scour trench using a hydroseeding device. The spraying pressure was constant, and a thin layer of sand was uniformly covered on the scour trench for roughening treatment, with the spraying thickness controlled at 2 cm. After spraying, the substrate was placed at room temperature for 7 days of curing. Then, the original soil scour method was used for scour, with a water flow rate of 120 L / h and a slope of 10° and 20° for the scour trench. During the scour process, the damage to the substrate was observed and recorded, such as gully formation, peeling, or overall sliding. When the volume of the substrate remaining in the scour trench was visually judged to be about one-third of the initial spraying volume, the water supply was stopped, and the scour material was collected. The scour resistance coefficient was calculated using the following method: AS = q·t / m, where AS represents the scour resistance coefficient, q is the water flow rate, t is the water scour time, and m is the dry weight of the substrate being scoured.

[0095] The shear strength test results are shown in Table 1:

[0096] Table 1

[0097]

[0098] The test results of the cracking effect of the ecological matrix material are shown in Table 2:

[0099] Table 2

[0100]

[0101] The test results for the erosion resistance coefficient are shown in Table 3:

[0102] Table 3

[0103]

[0104] Comprehensive performance analysis: The cohesive strength and internal friction angle of the ecological matrix materials in Examples 1-6 are much higher than those in all Comparative Examples 1-5. The possible reason is that the only difference between Example 5 and Comparative Examples 2 and 5 is that the incorporated fiber is a self-made modified polypropylene fiber, a maleic anhydride-grafted polypropylene fiber, or a commercially available polypropylene fiber. In Example 5, the self-made modified polypropylene fiber is first grafted with maleic anhydride and then undergoes a secondary acylation reaction with branched polyethyleneimine. The branched polyethyleneimine has a polyamine structure, which introduces a large number of amine groups on the surface of the polypropylene fiber and forms a more complex branched structure. This significantly increases the number of protruding peaks and depressions on the fiber surface of the self-made modified polypropylene fiber of this application, resulting in a significant increase in its specific surface area and roughness. This not only greatly enhances the hydrophilicity of the fiber, which is conducive to its uniform dispersion in the ecological matrix, but also strengthens the physical embedding and interfacial bonding between the fiber and the matrix, thereby giving the ecological matrix material higher cohesive strength and resistance to shear failure.

[0105] Comparing Example 5, Comparative Example 3, and Comparative Example 4, it can be found that the self-made modified diatomaceous earth, after amination and grafting with polybutylene itaconic acid, compared with unmodified diatomaceous earth and diatomaceous earth treated only with amination, shows that the amination and grafting treatment successfully grafted polybutylene itaconic acid chains onto the surface of the self-made modified diatomaceous earth, forming a core-shell complex with a network structure. This structure not only endows the self-made modified diatomaceous earth with more active terminal hydroxyl groups and double bonds, but also provides more active crosslinking points. This enhances its reactivity and free volume; moreover, strong chemical bonds are formed between diatomite and polybutylene ester chains, which are stronger than the intermolecular forces of polybutylene ester. Therefore, when the ecological matrix material is subjected to stress and deformation, the self-made modified diatomite in this application can exert a significant stress release and bridging effect, effectively disperse stress, prevent crack propagation, and ensure the structural integrity of the matrix material under environmental changes such as dryness and swelling. In addition, the diatomite is also relatively lightweight, which can ensure the stability of the slope under the western Sichuan plateau.

[0106] The difference between Comparative Example 1 and Example 5 is that the modification of diatomaceous earth was omitted, and commercially available diatomaceous earth was added directly; the modification of polypropylene fiber was omitted, and commercially available polypropylene fiber was added directly; it also showed the worst erosion resistance, indicating that it is difficult to resist water erosion by directly using commercially available materials.

[0107] The ecological matrix materials in Examples 1-5 of this application contain self-made modified diatomaceous earth, which can impart micro-stress dispersion and bridging capabilities to the matrix materials. Combined with the strong physical anchoring achieved by the self-made modified polypropylene fiber in the matrix due to the improved hydrophilicity resulting in uniform dispersion and surface roughening, the synergistic effect of the two not only improves the overall mechanical strength and crack resistance of the matrix materials, but also makes the internal structure of the matrix materials more compact and the pore distribution more reasonable. This tough and stable structure can effectively resist the impact of rainwater and the erosion of runoff, reduce soil erosion, and thus have excellent rainwater erosion resistance. It can effectively protect the slope surface and promote the rapid establishment and stable growth of vegetation.

[0108] 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 description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A substrate material for ecological restoration of slopes in the western Sichuan plateau, characterized in that, By weight, its specific composition is as follows: 80-100 parts planting soil, 8-15 parts self-made modified diatomaceous earth, 4-8 parts biochar, 10-18 parts organic fertilizer, 2-5 parts cement, 0.3-1.5 parts nano silica, 0.5-1.5 parts wood fiber, 1.0-3.0 parts self-made modified polypropylene fiber, 1.5-3.5 parts slow-release compound fertilizer, 0.3-0.8 parts sodium carboxymethyl cellulose, and 35-50 parts water; The self-made modified diatomaceous earth was prepared by the following method: Aminated diatomaceous earth was placed in DMF and ultrasonically dispersed for 15 min to form a suspension; polybutylene itaconic acid was added to DMF and stirred until completely dissolved to form a polybutylene itaconic acid solution; under inert gas protection, the polybutylene itaconic acid solution was slowly added dropwise to the suspension while stirring. During continuous stirring, the temperature of the reaction system was raised to 100 degrees Celsius, and stirring was maintained for 12 h; after the reaction was completed, heating was stopped and the reaction system was allowed to cool naturally to room temperature; the solid product was separated by filtration and washed three times with anhydrous ethanol to remove unreacted substances; then the product was placed in a vacuum drying oven and dried to constant weight to obtain the self-made modified diatomaceous earth. The self-made modified polypropylene fiber was prepared by the following method: maleic anhydride-grafted polypropylene fiber was placed in a reaction vessel, xylene was added, the reaction vessel was sealed, and the reaction vessel was shaken at room temperature for 2 hours; after shaking, a dispersion of branched polyethyleneimine and a dispersion of dicyclohexylcarbodiimine were added sequentially; then the temperature was raised to 45 degrees Celsius, and the reaction was continued to be shaken for 8 hours; after the reaction was completed, the reaction solution was filtered out, and the fiber was recovered; the fiber was washed twice with acetone, then washed twice with deionized water, and finally dried in a vacuum oven at 60 degrees Celsius to constant weight to obtain the self-made modified polypropylene fiber.

2. The slope ecological restoration matrix material for the Sichuan-Western Plateau according to claim 1, characterized in that, By weight, its specific composition is as follows: 96 parts planting soil, 14 parts self-made modified diatomaceous earth, 7.5 parts biochar, 17 parts organic fertilizer, 4.5 parts cement, 1.3 parts nano silica, 1.3 parts wood fiber, 2.6 parts self-made modified polypropylene fiber, 3.3 parts slow-release compound fertilizer, 0.7 parts sodium carboxymethyl cellulose, and 48 parts water.

3. The slope ecological restoration matrix material for the Sichuan-Western Plateau according to claim 1, characterized in that, The biochar is one of peanut shell biochar or rice husk biochar.

4. The slope ecological restoration matrix material for the Sichuan-Western Plateau according to claim 1, characterized in that, The organic fertilizer is one of fermented cow manure, fermented sheep manure, or fermented chicken manure.

5. The slope ecological restoration matrix material for the Sichuan-Western Plateau according to claim 1, characterized in that, The slow-release compound fertilizer is composed of polyurethane-coated urea, potassium sulfate, and ammonium dihydrogen phosphate in a mass ratio of 1:1:

1.

6. The slope ecological restoration matrix material for the Sichuan-Western Plateau according to claim 1, characterized in that, The aminated diatomaceous earth was prepared by the following method: Diatomaceous earth was placed in a beaker, soaked in HCl solution for 1 hour, and then the treated diatomaceous earth particles were thoroughly washed with ultrapure water until neutral. Finally, it was placed in a vacuum dryer at 60 degrees Celsius for 12 hours. The HCl-treated diatomaceous earth particles were mixed into an ethanol solution containing APTES. The mixture was ultrasonically treated for 30 minutes to obtain a uniformly dispersed suspension. The suspension was stirred at 60 degrees Celsius for 8 hours to ensure that the amination reaction was complete. The product was collected by centrifugation and washed several times with ethanol and deionized water. The obtained product was placed in a vacuum dryer at 60 degrees Celsius for 12 hours to prepare the aminated diatomaceous earth.

7. The slope ecological restoration matrix material for the Sichuan-Western Plateau according to claim 1, characterized in that, The number average molecular weight of branched polyethyleneimine is 600-1500.

8. The method for preparing a slope ecological restoration matrix material for the Sichuan-Western Plateau as described in claim 1, characterized in that, The preparation method is as follows: planting soil, self-made modified diatomaceous earth, biochar, cement, nano silica, wood fiber, and self-made modified polypropylene fiber are added to a mixer in the following order according to the mass ratio, and stirred evenly for 3-5 minutes; after being thoroughly stirred, organic fertilizer, slow-release compound fertilizer, and sodium carboxymethyl cellulose are added, and stirring is continued for 3-5 minutes; finally, water is added according to the ratio, and stirred evenly for 5-8 minutes to obtain a slope ecological restoration matrix material for the western Sichuan plateau.

Images