Soil improving ecological base material for ecological slope protection as well as preparation method and application of soil improving ecological base material

Abstract

The invention relates to the field of slope soil protection, in particular to an improved soil ecological base material for ecological slope protection and a preparation method and application of the improved soil ecological base material. The improved soil ecological base material is used for high-cold, high-humidity and high-altitude areas; the improved soil ecology base material comprises the following components: an anti-skid, anti-ultraviolet and freeze-thaw-resistant layer; and a soil adaptation layer; wherein the anti-skid, anti-ultraviolet and freeze-thaw-resistant layer comprises modified plant fibers and an anti-ultraviolet and freeze-thaw-resistant composite material; the soil adaptation layer contains a water absorption composite material. The prepared improved soil ecological base material has good freeze-thaw stability, excellent water erosion resistance and water retention performance, is eco-friendly and degradable, and is used for ecological slope protection in high-cold, high-humidity and high-altitude areas.

Description

Technical Field

[0001] This disclosure relates to the field of slope soil protection, and in particular to an improved soil ecological substrate for ecological slope protection, its preparation method and application. Background Technology

[0002] High-altitude, cold, and humid environments are an important component of plateau environments worldwide and are vital ecological functional zones on Earth, possessing unique ecosystems and rich biodiversity. my country also has areas like the Ruoergai Grassland Wetland. These ecosystems play a crucial role in maintaining regional ecological balance, regulating climate, conserving water resources, and protecting soil and water. However, in recent years, due to natural factors (such as frequent freeze-thaw cycles caused by climate change) and human activities (such as overgrazing and engineering construction), some areas in these regions have experienced varying degrees of ecological degradation. Landslides and collapses occur frequently, seriously threatening the stability and integrity of wetland ecosystems and adversely affecting the surrounding ecological environment and human production and lives.

[0003] In the field of ecological slope protection and restoration, the commonly used restoration materials mainly include the following: (1) Traditional concrete slope protection, although it has high strength and stability, it has poor air permeability and is not permeable to water, which is not conducive to vegetation growth and cannot be integrated with the wetland ecosystem. Moreover, it is prone to cracks under the action of freeze-thaw cycle, resulting in structural damage. (2) Ordinary soil mixed with grass seed spraying, although this method can promote vegetation growth, ordinary soil is easily affected by freeze-thaw action in the cold and humid wetland environment, resulting in structural damage, soil loss, and difficulty in long-term stable vegetation growth, and the restoration effect is difficult to last. (3) Ecological substrate mixed with organic fiber and soil, although it improves the stability of soil and the growth conditions of vegetation to a certain extent, in the extreme environment of such areas, these organic fibers are often unable to withstand long-term freeze-thaw cycle and high humidity conditions, and are prone to degradation and failure.

[0004] Therefore, there is an urgent need for a modified soil ecological substrate that combines good freeze-thaw stability, excellent water erosion resistance and water retention performance, and is eco-friendly and biodegradable, for ecological slope protection in high-altitude, cold, and humid regions. Summary of the Invention

[0005] This disclosure provides an improved soil ecological substrate for ecological slope protection, its preparation method, and its application, in order to address the shortcomings of related technologies.

[0006] According to a first aspect of the present disclosure, a modified soil ecological substrate for ecological slope protection is provided, the modified soil ecological substrate being used in high-altitude, cold, and humid regions; the modified soil ecological substrate comprises the following:

[0007] Anti-slip, UV-resistant, and freeze-thaw resistant layer; and

[0008] Soil adaptation layer;

[0009] The anti-slip, UV-resistant, and freeze-thaw resistant layer contains modified plant fibers and UV-resistant freeze-thaw resistant composite materials; the soil adaptation layer contains water-absorbing composite materials.

[0010] In one aspect of this disclosure, the soil adaptation layer comprises the following components in parts by weight:

[0011] 100-200 parts by weight of peat, 15-30 parts by weight of fly ash, 15-30 parts by weight of metakaolin, 20-50 parts by weight of water-absorbing composite material, 65-120 parts by weight of water-absorbing biochar, and 15-35 parts by weight of bentonite.

[0012] In one aspect of this disclosure, the water-absorbing composite material is obtained by compounding vermiculite and acrylic polymer; the water-absorbing composite material is prepared by the following steps:

[0013] Step 1-a: Provide guiding gum; add guiding gum to water, and then sequentially heat and cool to obtain the first solution;

[0014] Step 2-a: Add ammonium persulfate to the first solution to obtain the second mixture;

[0015] Step 3-a: Add acrylic acid and N,N'-methylenebisacrylamide to an alkaline solution, stir, and then add vermiculite; then heat and stir to obtain a third mixture;

[0016] Step 4-a: Under inert gas protection, the third mixture is added to the second mixture and reacted for 2-5 hours; then the obtained solid product is taken out, dried, crushed and sieved to obtain the water-absorbing composite material.

[0017] In one aspect of this disclosure, the water-absorbing biochar is prepared by the following steps:

[0018] Step 1-b: Provide biochar; after crushing, sieving, and washing, add the biochar to water;

[0019] Step 2-b: Add polyacrylamide to water, stir, and dry the resulting mixture to constant weight; to obtain the water-absorbing biochar.

[0020] In one aspect of this disclosure, the anti-slip, UV-resistant, and freeze-thaw resistant layer comprises the following components in parts by weight:

[0021] 100-200 parts by weight of peat moss, 20-40 parts by weight of modified plant fiber, 10-25 parts by weight of UV-resistant and freeze-thaw resistant composite material, and 5-10 parts by weight of polyethylene glycol.

[0022] In one aspect of this disclosure, the UV-resistant and freeze-thaw resistant composite material is prepared by the following steps:

[0023] Step 1-c: Use mangosteen shells as raw material to prepare mangosteen shell polysaccharide; and use the remaining plant residue after preparing mangosteen shell polysaccharide as raw material to prepare modified plant fiber.

[0024] Step 2-c: Add the mangosteen shell polysaccharide and chitosan to water, then heat to 80℃-95℃ and stir, and add citric acid and glutaraldehyde while maintaining the temperature; to obtain the fourth mixture;

[0025] Step 3-c: Provide dopamine hydrochloride, dissolve the dopamine hydrochloride in an ethanol solution, then add it to the fourth mixture, and then let it stand at 80℃-95℃ for 2-6 hours to obtain a gel-like solid;

[0026] Step 4-c: Dry the gel-like solid to constant weight to obtain the UV-resistant and freeze-thaw resistant composite material.

[0027] In one aspect of this disclosure, the modified plant fiber is prepared by the following steps:

[0028] Step 1-d: Use the plant residue remaining after preparing mangosteen polysaccharide from mangosteen shells as raw material; wash and dry the plant residue to obtain dried plant fiber;

[0029] Step 2-d: Add chloromethyl ethylene oxide to anhydrous ethanol, then add the dried plant fiber obtained in step 1-d, keep stirring and add tetrabutylammonium bromide, reflux at 55℃-65℃ for 2-6 hours; to obtain surface-grafted plant fiber.

[0030] Step 3-d: Dissolve polyethyleneimine in anhydrous ethanol, then add the surface-grafted plant fiber obtained in step 2-d, purge with nitrogen for protection, and react at 65℃-75℃ for 2-6 hours. After washing and drying, the modified plant fiber is obtained.

[0031] In one aspect of this disclosure, the mangosteen shell polysaccharide is prepared by the following steps:

[0032] Step 1-e: Provide mangosteen shells as raw materials, and after crushing and drying the mangosteen shells, obtain mangosteen shell powder;

[0033] Step 2-e: Add the mangosteen shell powder to water and perform ultrasonic extraction; perform ultrasonic extraction 2-3 times, combine the filtrates and concentrate them, then add ethanol solution to precipitate the mangosteen shell polysaccharide, collect the white precipitate, and dry it to obtain the mangosteen shell polysaccharide.

[0034] According to a second aspect of the present disclosure, a method for preparing the aforementioned improved soil ecological substrate for ecological slope protection is provided, the method comprising the following steps:

[0035] Step 1: Mix peat, fly ash, metakaolin, water-absorbing composite material, water-absorbing biochar, and bentonite, then add the mixture into a mold and compact it to obtain a soil adaptation layer.

[0036] Step 2: Mix peat soil, modified plant fiber, UV-resistant and freeze-thaw resistant composite material and polyethylene glycol, then add it to the mold, lay it on top of the soil adaptation layer, and compact it to obtain an anti-slip, UV-resistant and freeze-thaw resistant layer;

[0037] Step 3: Demolding to obtain the improved soil ecological substrate for ecological slope protection.

[0038] According to a third aspect of the present disclosure, the aforementioned improved soil ecological substrate for ecological slope protection is provided for use in ecological slope protection in high-altitude, cold, and humid regions.

[0039] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0040] As can be seen from the above embodiments, this disclosure prepares a modified soil ecological substrate that has good freeze-thaw stability, excellent water erosion resistance and water retention performance, and is eco-friendly and biodegradable, for ecological slope protection in high-altitude, cold, and humid regions.

[0041] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Detailed Implementation

[0042] Exemplary embodiments will now be described in detail. The implementation methods described in the following exemplary embodiments do not represent all implementation methods consistent with this disclosure.

[0043] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0044] For the sake of brevity, this article only discloses a few specific numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0045] In this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0046] In this description, unless otherwise stated, "above" and "below" include the stated number.

[0047] Unless otherwise stated, the terms used in this disclosure have their common meanings as commonly understood by those skilled in the art. Unless otherwise stated, the values ​​of the parameters mentioned in this disclosure can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this disclosure).

[0048] The term "about" is used to describe and indicate small variations. When used in conjunction with an event or situation, the term may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately. For example, when used in conjunction with numerical values, the term may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. Additionally, quantities, ratios, and other numerical values ​​are sometimes presented in range format herein. It should be understood that such range format is for convenience and brevity and should be interpreted flexibly to include not only numerical values ​​explicitly specified as range limits but also all individual numerical values ​​or subranges covered within the range, as if each numerical value and subrange were explicitly specified.

[0049] The list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another instance, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.

[0050] In this disclosure, the water-absorbing composite material in the soil adaptation layer is obtained by compounding vermiculite and acrylic polymer. Its function is to rapidly absorb and store a large amount of water during the snowmelt period, preventing slope runoff erosion. Furthermore, the vermiculite sheets act as nanofillers, hindering the slippage of acrylic segments during freeze-thaw cycles. Erythrina variegata gum acts as a crosslinking point and adhesive during polymerization, binding vermiculite and acrylic segments via hydrogen bonds / coordinate bonds, reducing weight loss of acrylic segments during freeze-thaw cycles. In addition, the acrylic-Erythrina variegata gum copolymer in the water-absorbing composite material prepared in this disclosure gradually breaks down under the action of natural soil microorganisms (Bacillus, Pseudomonas), ultimately generating CO2, H2O, and humic acid. Meanwhile, vermiculite can be converted into soil clay particles, improving soil structure.

[0051] In this disclosure, the water-absorbing biochar in the soil adaptation layer can also rapidly absorb and store large amounts of water during the snowmelt season, preventing slope runoff erosion; and during the dry season, the porous structure of the biochar itself can also provide oxygen and growth space for plant roots and beneficial microorganisms, reducing the risk of root rot in high humidity environments.

[0052] In this disclosure, the polymer network formed by the UV-resistant and freeze-thaw resistant composite material in the anti-slip, UV-resistant, and freeze-thaw resistant layer can still maintain a relatively small mass loss rate and volume shrinkage rate after repeated freeze-thaw cycles from a cold environment (-20°C and below) to normal temperature (20°C and above). Furthermore, in high-altitude, cold, and humid regions with strong ultraviolet radiation, this disclosure utilizes the UV resistance of mangosteen shell polysaccharide. Therefore, the obtained mangosteen shell polysaccharide / chitosan-dopamine network has a certain resistance to UV aging and can maintain the integrity of the polymer network under ultraviolet radiation in high-altitude regions.

[0053] In this disclosure, modified fibers are prepared using the plant residue remaining after the preparation of mangosteen polysaccharide from mangosteen shells, thus achieving full utilization of the raw materials. At the same time, after grafting chloromethyl ethylene oxide-polyethyleneimine onto the fiber surface, flexible amine segments are obtained. These flexible amine segments can form hydrogen bonds / coordinate bonds with the UV-resistant and freeze-thaw resistant composite material and polyethylene glycol in the anti-slip, UV-resistant, and freeze-thaw resistant layer, further improving its stability in freeze-thaw cycles and also playing an anti-slip role.

[0054] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention were obtained through conventional commercial means. Unless otherwise specified, all contents mentioned below are mass contents. Unless otherwise specified, it is understood that the process was carried out at room temperature.

[0055] Example:

[0056] Example 1:

[0057] Example 1 includes the following steps:

[0058] 1. Preparation of water-absorbing composite materials:

[0059] Weigh 2 parts by weight of Erythrina crista-galli gum; add the Erythrina crista-galli gum to 40 parts by weight of water, then heat to 65°C, keep warm for 1 hour, and then cool down to 50°C to obtain the first solution; keep the temperature at 50°C and add 0.19 parts by weight of ammonium persulfate to the first solution to obtain the second mixture.

[0060] 12 parts by weight of acrylic acid and 0.012 parts by weight of N,N'-methylenebisacrylamide were added to 30 parts by weight of NaOH solution (2wt%). After thorough stirring, 8 parts by weight of vermiculite were added. The mixture was then heated to 70°C and stirred to obtain a third mixture.

[0061] Under nitrogen protection, the third mixture (70°C) was added to the second mixture (50°C) and reacted for 3 hours. The resulting solid product was then removed, dried, pulverized, and passed through a 20-mesh sieve to obtain the water-absorbing composite material of Example 1.

[0062] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0063] 2. Preparation of water-absorbing biochar:

[0064] Weigh 80 parts by weight of biochar; crush the biochar, pass it through a 20-mesh sieve, wash it, and add it to 250 parts by weight of water; add 40 parts by weight of polyacrylamide to the water, stir, and then dry the resulting mixture directly to constant weight; thus obtaining the water-absorbing biochar of Example 1.

[0065] 3. Preparation of UV-resistant and freeze-thaw resistant composite materials:

[0066] 3.1. Preparation of mangosteen shell polysaccharide:

[0067] Weigh 500 parts by weight of mangosteen shells, crush and dry them to obtain mangosteen shell powder; add the mangosteen shell powder to 8000 parts by weight of water for ultrasonic extraction; perform ultrasonic extraction 3 times, with an ultrasonic extraction temperature of 55℃, an ultrasonic time of 1 hour, and an ultrasonic power of 216W; combine the filtrates and concentrate them to 1 / 5 of the original volume, then add 95% ethanol solution, a white precipitate appears, continue to add 95% ethanol solution until the white precipitate no longer increases; collect the white precipitate, dry it to obtain 12 parts by weight of mangosteen shell polysaccharide.

[0068] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0069] 3.2. Preparation of UV-resistant and freeze-thaw resistant composite materials:

[0070] 12 parts by weight of mangosteen shell polysaccharide and 15 parts by weight of chitosan were added to 160 parts by weight of water, then the mixture was heated to 90°C and stirred. 2.5 parts by weight of citric acid and 0.8 parts by weight of glutaraldehyde were added and the temperature was maintained to obtain a fourth mixture. 8 parts by weight of dopamine hydrochloride were weighed and dissolved in 30 parts by weight of 95% ethanol solution. The solution was then added dropwise to the fourth mixture and kept at 85°C for 2.5 hours to obtain a gel-like solid. The gel-like solid was dried to constant weight to obtain the UV-resistant and freeze-thaw resistant composite material of Example 2.

[0071] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0072] 3.3. Preparation of modified plant fibers:

[0073] 100 parts by weight of the plant residue remaining after preparing mangosteen polysaccharide from the aforementioned mangosteen shells were weighed as raw materials; the plant residue was washed and dried to obtain dried plant fibers; 10 parts by weight of chloromethyl ethylene oxide were added to 250 parts by weight of anhydrous ethanol, and then the obtained dried plant fibers were added. The mixture was stirred and 5 parts by weight of tetrabutylammonium bromide were added. The mixture was refluxed at 60°C for 3 hours to obtain plant fibers with surface grafting treatment.

[0074] 38 parts by weight of polyethyleneimine were dissolved in 250 parts by weight of anhydrous ethanol, and then the surface-grafted plant fibers were added. Nitrogen gas was introduced for protection, and the reaction was carried out at 70°C for 3 hours. The product after reaction was washed and dried to obtain modified plant fibers.

[0075] 4. Preparation of improved soil ecological substrate:

[0076] 150 parts by weight of peat soil, 20 parts by weight of fly ash, 18 parts by weight of metakaolin, 35 parts by weight of water-absorbing composite material, 100 parts by weight of water-absorbing biochar, and 20 parts by weight of bentonite were mixed, then added to a mold and compacted (0.6 MPa) to obtain a soil adaptation layer. 120 parts by weight of peat soil, 35 parts by weight of modified plant fiber, 12 parts by weight of UV-resistant and freeze-thaw resistant composite material, and 8 parts by weight of polyethylene glycol were mixed, then added to a mold and laid on top of the soil adaptation layer. After compaction (0.6 MPa), an anti-slip, UV-resistant, and freeze-thaw resistant layer was obtained. Finally, the mold was removed to obtain the improved soil ecological substrate for ecological slope protection of Example 1.

[0077] Example 2:

[0078] Example 2 includes the following steps:

[0079] 1. Preparation of water-absorbing composite materials:

[0080] Weigh 2 parts by weight of Erythrina crista-galli gum; add the Erythrina crista-galli gum to 40 parts by weight of water, then heat to 65°C, keep warm for 1 hour, and then cool down to 50°C to obtain the first solution; keep the temperature at 50°C and add 0.19 parts by weight of ammonium persulfate to the first solution to obtain the second mixture.

[0081] 12 parts by weight of acrylic acid and 0.012 parts by weight of N,N'-methylenebisacrylamide were added to 30 parts by weight of NaOH solution (2wt%). After thorough stirring, 8 parts by weight of vermiculite were added. The mixture was then heated to 70°C and stirred to obtain a third mixture.

[0082] Under nitrogen protection, the third mixture (70°C) was added to the second mixture (50°C) and reacted for 3 hours. The resulting solid product was then removed, dried, pulverized, and passed through a 20-mesh sieve to obtain the water-absorbing composite material of Example 2.

[0083] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0084] 2. Preparation of water-absorbing biochar:

[0085] Weigh 80 parts by weight of biochar; crush the biochar, pass it through a 20-mesh sieve, wash it, and add it to 250 parts by weight of water; add 40 parts by weight of polyacrylamide to the water, stir, and then dry the resulting mixture directly to constant weight; thus obtaining the water-absorbing biochar of Example 2.

[0086] 3. Preparation of UV-resistant and freeze-thaw resistant composite materials:

[0087] 3.1. Preparation of mangosteen shell polysaccharide:

[0088] Weigh 500 parts by weight of mangosteen shells, crush and dry them to obtain mangosteen shell powder; add the mangosteen shell powder to 8000 parts by weight of water for ultrasonic extraction; perform ultrasonic extraction 3 times, with an ultrasonic extraction temperature of 55℃, an ultrasonic time of 1 hour, and an ultrasonic power of 216W; combine the filtrates and concentrate them to 1 / 5 of the original volume, then add 95% ethanol solution, a white precipitate appears, continue to add 95% ethanol solution until the white precipitate no longer increases; collect the white precipitate, dry it to obtain 12 parts by weight of mangosteen shell polysaccharide.

[0089] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0090] 3.2. Preparation of UV-resistant and freeze-thaw resistant composite materials:

[0091] 12 parts by weight of mangosteen shell polysaccharide and 15 parts by weight of chitosan were added to 160 parts by weight of water, then the mixture was heated to 90°C and stirred. 2.5 parts by weight of citric acid and 0.8 parts by weight of glutaraldehyde were added and the temperature was maintained to obtain a fourth mixture. 8 parts by weight of dopamine hydrochloride were weighed and dissolved in 30 parts by weight of 95% ethanol solution. The solution was then added dropwise to the fourth mixture and kept at 85°C for 2.5 hours to obtain a gel-like solid. The gel-like solid was dried to constant weight to obtain the UV-resistant and freeze-thaw resistant composite material of Example 1.

[0092] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0093] 3.3. Provide plant fiber:

[0094] 100 parts by weight of the plant residue remaining after preparing mangosteen polysaccharide from the aforementioned mangosteen shells were weighed as raw materials; the plant residue was washed and dried to obtain dried plant fiber for direct use.

[0095] 4. Preparation of improved soil ecological substrate:

[0096] 150 parts by weight of peat soil, 20 parts by weight of fly ash, 18 parts by weight of metakaolin, 35 parts by weight of water-absorbing composite material, 100 parts by weight of water-absorbing biochar, and 20 parts by weight of bentonite were mixed, then added to a mold and compacted (0.6 MPa) to obtain a soil adaptation layer. 120 parts by weight of peat soil, 35 parts by weight of dried plant fiber, 12 parts by weight of UV-resistant and freeze-thaw resistant composite material, and 8 parts by weight of polyethylene glycol were mixed, then added to a mold and laid on top of the soil adaptation layer. After compaction (0.6 MPa), an anti-slip, UV-resistant, and freeze-thaw resistant layer was obtained. Finally, the mold was removed to obtain the improved soil ecological substrate for ecological slope protection as described in Example 2.

[0097] The main difference between Example 2 and Example 1 is that Example 2 does not modify the plant fibers.

[0098] Example 3:

[0099] Example 3 includes the following steps:

[0100] 1. Preparation of water-absorbing composite materials:

[0101] Weigh 2 parts by weight of Erythrina crista-galli gum; add the Erythrina crista-galli gum to 40 parts by weight of water, then heat to 65°C, keep warm for 1 hour, and then cool down to 50°C to obtain the first solution; keep the temperature at 50°C and add 0.19 parts by weight of ammonium persulfate to the first solution to obtain the second mixture.

[0102] 12 parts by weight of acrylic acid and 0.012 parts by weight of N,N'-methylenebisacrylamide were added to 30 parts by weight of NaOH solution (2wt%). After thorough stirring, 8 parts by weight of vermiculite were added. The mixture was then heated to 70°C and stirred to obtain a third mixture.

[0103] Under nitrogen protection, the third mixture (70°C) was added to the second mixture (50°C) and reacted for 3 hours. The resulting solid product was then removed, dried, pulverized, and passed through a 20-mesh sieve to obtain the water-absorbing composite material of Example 3.

[0104] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0105] 2. Preparation of water-absorbing biochar:

[0106] Weigh 80 parts by weight of biochar; crush the biochar, pass it through a 20-mesh sieve, wash it, and add it to 250 parts by weight of water; add 40 parts by weight of polyacrylamide to the water, stir, and then dry the resulting mixture directly to constant weight; thus obtaining the water-absorbing biochar of Example 3.

[0107] 3. Preparation of UV-resistant and freeze-thaw resistant composite materials:

[0108] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0109] 3.2. Preparation of UV-resistant and freeze-thaw resistant composite materials:

[0110] 27 parts by weight of chitosan were added to 160 parts by weight of water, then the mixture was heated to 90°C and stirred. 2.5 parts by weight of citric acid and 0.8 parts by weight of glutaraldehyde were added and the temperature was maintained to obtain a fourth mixture. 8 parts by weight of dopamine hydrochloride were weighed and dissolved in 30 parts by weight of 95% ethanol solution. The solution was then added dropwise to the fourth mixture and kept at 85°C for 2.5 hours to obtain a gel-like solid. The gel-like solid was dried to constant weight to obtain the UV-resistant and freeze-thaw resistant composite material of Example 3.

[0111] The above steps can be repeated multiple times to obtain a sufficient amount of product for subsequent reactions.

[0112] 3.3. Preparation of modified plant fibers:

[0113] Since no mangosteen shell polysaccharide was prepared in Example 3, the modified plant fiber obtained in Example 1 was used directly as the modified plant fiber in Example 3.

[0114] 4. Preparation of improved soil ecological substrate:

[0115] 150 parts by weight of peat soil, 20 parts by weight of fly ash, 18 parts by weight of metakaolin, 35 parts by weight of water-absorbing composite material, 100 parts by weight of water-absorbing biochar, and 20 parts by weight of bentonite were mixed, then added to a mold and compacted (0.6 MPa) to obtain a soil adaptation layer. 120 parts by weight of peat soil, 35 parts by weight of modified plant fiber, 12 parts by weight of UV-resistant and freeze-thaw resistant composite material, and 8 parts by weight of polyethylene glycol were mixed, then added to a mold and laid on top of the soil adaptation layer. After compaction (0.6 MPa), an anti-slip, UV-resistant, and freeze-thaw resistant layer was obtained. Finally, the mold was removed to obtain the improved soil ecological substrate for ecological slope protection as described in Example 3.

[0116] Performance testing:

[0117] The samples from Examples 1-3 were cured at 20±2℃ and RH≥95% for 7 days to simulate a high humidity environment. Then, the samples from Examples 1-3 were placed in an environment at -20℃ for 5 hours, followed by a temperature increase to 5℃ over 48 hours, maintained for 24 hours, and then a temperature decrease to -20℃ over another 48 hours. This process was repeated 5 times. The compressive strength retention rate, surface spalling mass ratio, and whether vertical slippage occurred in the samples were tested. The results are shown in Table 1.

[0118] Table 1

[0119] Example Compressive strength retention rate Surface peeling quality ratio Does the sample body exhibit vertical slippage? Example 1 88% ＜1% No slippage occurred Example 2 81% 6.0% No obvious slippage was observed. Example 3 83% 3.2% No obvious slippage was observed.

[0120] The samples from Examples 1-3 were cured at 20±2℃ and RH≥95% for 7 days to simulate a high humidity environment. Then, the samples from Examples 1-3 were placed in an environment at -20℃ for 5 hours, followed by a temperature increase to 5℃ over 48 hours, maintained for 24 hours, and then a temperature decrease to -20℃ over another 48 hours. This process was repeated 5 times. All steps were performed under UV irradiation to simulate a high UV intensity environment. The compressive strength retention rate, surface spalling mass ratio, and vertical slippage of the samples were tested. The results are shown in Table 2.

[0121] Table 2

[0122] Example Compressive strength retention rate Surface peeling quality ratio Does the sample body exhibit vertical slippage? Example 1 86% ＜1% No slippage occurred Example 2 78% 6.1% No obvious slippage was observed. Example 3 72% 8.6% Slippage occurs

[0123] Compared to Example 2, Example 1 has a significantly smaller surface peeling mass ratio. This is because after the fiber surface is grafted with chloromethyl ethylene oxide-polyethyleneimine, flexible amine segments are obtained. These flexible amine segments can form hydrogen bonds / coordination bonds with the UV-resistant and freeze-thaw resistant composite material and polyethylene glycol in the anti-slip, UV-resistant and freeze-thaw resistant layer, further improving its stability in freeze-thaw cycles and also playing an anti-slip role.

[0124] Compared to Example 3, Example 1 can still maintain a better morphology under ultraviolet irradiation. This is because Example 1 utilizes the UV resistance of mangosteen shell polysaccharide. Therefore, the obtained mangosteen shell polysaccharide / chitosan-dopamine network has a certain ability to resist ultraviolet aging and can maintain the integrity of the polymer network under ultraviolet irradiation in high-altitude areas.

[0125] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.

Claims

1. A modified soil ecological substrate for ecological slope protection, wherein the modified soil ecological substrate is used in high-altitude, cold, and humid regions; characterized in that, The improved soil ecological substrate includes the following: Anti-slip, UV-resistant, and freeze-thaw resistant layer; and Soil adaptation layer; The anti-slip, UV-resistant, and freeze-thaw resistant layer contains modified plant fibers and UV-resistant freeze-thaw resistant composite materials; the soil adaptation layer contains water-absorbing composite materials.

2. The improved soil ecological substrate for ecological slope protection according to claim 1, characterized in that, The soil adaptation layer comprises the following components in parts by weight: 100-200 parts by weight of peat, 15-30 parts by weight of fly ash, 15-30 parts by weight of metakaolin, 20-50 parts by weight of water-absorbing composite material, 65-120 parts by weight of water-absorbing biochar, and 15-35 parts by weight of bentonite.

3. The improved soil ecological substrate for ecological slope protection according to claim 1 or 2, characterized in that, The water-absorbing composite material is obtained by compounding vermiculite and acrylic polymer; the water-absorbing composite material is prepared through the following steps: Step 1-a: Provide guiding gum; add guiding gum to water, and then sequentially heat and cool to obtain the first solution; Step 2-a: Add ammonium persulfate to the first solution to obtain the second mixture; Step 3-a: Add acrylic acid and N,N'-methylenebisacrylamide to an alkaline solution, stir, and then add vermiculite; then heat and stir to obtain a third mixture; Step 4-a: Under inert gas protection, the third mixture is added to the second mixture and reacted for 2-5 hours; then the obtained solid product is taken out, dried, crushed and sieved to obtain the water-absorbing composite material.

4. The improved soil ecological substrate for ecological slope protection according to claim 2, characterized in that, The water-absorbing biochar is prepared through the following steps: Step 1-b: Provide biochar; after crushing, sieving, and washing, add the biochar to water; Step 2-b: Add polyacrylamide to water, stir, and dry the resulting mixture to constant weight; to obtain the water-absorbing biochar.

5. The improved soil ecological substrate for ecological slope protection according to claim 1, characterized in that, The anti-slip, UV-resistant, and freeze-thaw resistant layer comprises the following components in parts by weight: 100-200 parts by weight of peat moss, 20-40 parts by weight of modified plant fiber, 10-25 parts by weight of UV-resistant and freeze-thaw resistant composite material, and 5-10 parts by weight of polyethylene glycol.

6. The improved soil ecological substrate for ecological slope protection according to claim 1 or 5, characterized in that, The UV-resistant and freeze-thaw resistant composite material is prepared through the following steps: Step 1-c: Use mangosteen shells as raw material to prepare mangosteen shell polysaccharide; and use the remaining plant residue after preparing mangosteen shell polysaccharide as raw material to prepare modified plant fiber. Step 2-c: Add the mangosteen shell polysaccharide and chitosan to water, then heat to 80℃-95℃ and stir, add citric acid and glutaraldehyde, and maintain the temperature; to obtain the fourth mixture; Step 3-c: Provide dopamine hydrochloride, dissolve the dopamine hydrochloride in an ethanol solution, then add it to the fourth mixture, and then let it stand at 80℃-95℃ for 2-6 hours to obtain a gel-like solid; Step 4-c: Dry the gel-like solid to constant weight to obtain the UV-resistant and freeze-thaw resistant composite material.

7. The improved soil ecological substrate for ecological slope protection according to claim 6, characterized in that, The modified plant fiber is prepared through the following steps: Step 1-d: Use the plant residue remaining after preparing mangosteen polysaccharide from mangosteen shells as raw material; wash and dry the plant residue to obtain dried plant fiber; Step 2-d: Add chloromethyl ethylene oxide to anhydrous ethanol, then add the dried plant fiber obtained in step 1-d, keep stirring and add tetrabutylammonium bromide, reflux at 55℃-65℃ for 2-6 hours; to obtain surface-grafted plant fiber. Step 3-d: Dissolve polyethyleneimine in anhydrous ethanol, then add the surface-grafted plant fiber obtained in step 2-d, purge with nitrogen for protection, and react at 65℃-75℃ for 2-6 hours. After washing and drying, the modified plant fiber is obtained.

8. The improved soil ecological substrate for ecological slope protection according to claim 6, characterized in that, The mangosteen shell polysaccharide was prepared by the following steps: Step 1-e: Provide mangosteen shells as raw materials, and after crushing and drying the mangosteen shells, obtain mangosteen shell powder; Step 2-e: Add the mangosteen shell powder to water and perform ultrasonic extraction; perform ultrasonic extraction 2-3 times, combine the filtrates and concentrate them, then add ethanol solution to precipitate the mangosteen shell polysaccharide, collect the white precipitate, and dry it to obtain the mangosteen shell polysaccharide.

9. A method for preparing the improved soil ecological substrate for ecological slope protection as described in any one of claims 1-8, characterized in that, The method includes the following steps: Step 1: Mix peat, fly ash, metakaolin, water-absorbing composite material, water-absorbing biochar, and bentonite, then add the mixture into a mold and compact it to obtain a soil adaptation layer. Step 2: Mix peat soil, modified plant fiber, UV-resistant and freeze-thaw resistant composite material and polyethylene glycol, then add it to the mold, lay it on top of the soil adaptation layer, and compact it to obtain an anti-slip, UV-resistant and freeze-thaw resistant layer; Step 3: Demolding to obtain the improved soil ecological substrate for ecological slope protection.

10. The application of the improved soil ecological substrate for ecological slope protection as described in any one of claims 1-8 in the ecological protection of slopes in high-altitude, cold, and humid regions.