High and steep slope strong freezing and thawing resistant vegetation block and green low-temperature freezing preparation method and application

Abstract

The invention discloses a high and steep slope strong freezing and thawing resistant vegetation block and a green low-temperature freezing preparation method and application, and aims at solving the core technical problems that an ecological restoration material is prone to structure instability, water and fertilizer are difficult to maintain, vegetation adaptability is poor, and construction is inconvenient. The method comprises the following steps: uniformly mixing soil, organic matters, a water-retaining agent, hydrothermal carbon and a slow-release fertilizer to obtain a substrate; then adding fibers and carrying out dry mixing to construct a three-dimensional reinforced framework; mixing a cementing agent, and stirring to prepare a flow-state mixture; laying in a mold by adopting a layered structure, and uniformly sowing suitable plant seeds on the surface layer to prepare a plant growing block prototype of the pre-buried seeds; through low-temperature freezing treatment and demolding air-drying treatment, the block is shaped into a block which is stable in structure, can be carried and assembled and is internally provided with a porous framework structure. The vegetation block has mechanical stability, excellent freeze-thaw resistance and ecological functionality, and is especially suitable for rapid ecological restoration of steep slopes in ecologically fragile environments such as Qinghai-Tibet Plateau and northwest cold and arid regions.

Description

Technical Field

[0001] This invention belongs to the field of ecological restoration and soil and water conservation technology, and relates to vegetation blocks used in the prevention and control of soil erosion and vegetation restoration and protection on steep slopes in cold and cold regions. In particular, it relates to a strong freeze-thaw resistant vegetation block for steep slopes and a green low-temperature freezing preparation method and application. Background Technology

[0002] With the continuous advancement of transportation infrastructure construction, urban expansion, and energy and mineral development in mountainous areas, numerous steep slopes have been cut and excavated, resulting in exposed slopes exceeding 70°. Under the combined effects of freeze-thaw cycles and water erosion, these slopes are highly susceptible to erosion, gully erosion, and landslides, severely impacting road safety and regional ecological stability. Vegetation restoration on steep slopes in cold regions is a long-term engineering challenge, requiring materials that are lightweight, porous, adaptable to vegetation, and possess sufficient structural stability.

[0003] Currently, the most widely used artificial vegetation techniques include hydroseeding, spray-mixed vegetation, vegetation mats, and geotextile covering. Among them, hydroseeding and spray-mixed vegetation involve spraying a mixture of "topsoil, water-retaining materials, seeds, and binders" onto the slope surface. This method is suitable for low to medium slopes and can form vegetation cover in a relatively short time. Covering materials such as vegetation mats and geotextiles rely on a fiber skeleton, a small amount of substrate, and plant seeds. After being laid on the slope, they provide basic water and soil retention functions for the plants and are often used in gentle or medium slope areas.

[0004] However, the aforementioned technologies are poorly applicable on steep slopes. Taking hydroseeding as an example, the mixed substrate is prone to sliding under gravity on slopes greater than 60°. After rainfall, the substrate softens and is washed away by runoff, leading to substrate loss, seed exposure, and increased risk of re-erosion. Furthermore, hydroseeding materials are typically applied in thin layers. When steep rock faces lack sufficient roughness, substrate adhesion is significantly reduced, often requiring repeated application, increasing costs, and resulting in unstable effectiveness. Related studies show that on steep bare rock surfaces, hydroseeding technology struggles to maintain a survival rate of ≥70% for extended periods, with generally low seed retention rates. While vegetation mats and geotextiles offer some erosion resistance, their thin substrates and limited water retention capacity rely primarily on rainfall or external irrigation to maintain humidity. Vegetation roots struggle to penetrate the thin substrate to reach deeper soil layers, resulting in low plant survival rates and weak resilience. Simultaneously, vegetation mats laid on steep slopes are prone to curling or misalignment under gravity, and edge curling and tearing are common after runoff. Therefore, such materials are unlikely to provide long-term and stable ecological restoration effects for steep slopes.

[0005] In recent years, to improve the surface stability of steep rock slopes, "soil-cementant-plant" composite systems such as vegetated concrete and polyurethane composite substrates have been increasingly used for the protection of bare rock slopes or slopes with thin soil cover. These technologies, through the bonding of cement, polyurethane, and other cementing materials with the soil, significantly enhance erosion and shear strength, and can, to some extent, suppress topsoil slippage and surface erosion. However, vegetated concrete is prone to cracking and strength reduction under freeze-thaw cycles; simultaneously, the high cement content and dense structure hinder root penetration and soil microbial activity, limiting long-term ecological restoration effects.

[0006] For steep slopes in cold and high-altitude regions, significant freeze-thaw erosion is also a significant problem. Freeze-thaw cycles cause volume expansion and contraction and structural damage to the soil-rock media on the slope surface, leading to soil disintegration, changes in pore connectivity, and accelerated fine particle migration. This accelerates slope erosion and vegetation degradation, posing serious safety hazards to highways, railways, and water conservancy projects. Furthermore, seed attachment and early fixation remain key challenges in ecological restoration of steep slopes. Existing technologies such as hydroseeding, eco-bags, and vegetation strips often involve mixing seeds with substrates and then spraying or covering the slope surface. However, on steep slopes, seeds mainly rely on substrate friction and the resistance of a thin layer of soil to remain on the slope, and are easily washed away or slide away with the substrate during heavy rainfall or snowmelt runoff. For almost vertical rock retaining walls or extremely steep slopes, it is often necessary to use structures such as V-grooves and ribbed vegetation bags to support the substrate in stages, but these methods are complex and highly dependent on site conditions.

[0007] Currently, several technologies have explored the greening effect of vegetation mats / blocks. CN119924159A uses lightweight porous substrate to prepare vegetation blocks, CN114041381A proposes multi-layered vegetation mats for slope soil and water conservation, and CN114600731A uses lightweight aggregates and introduces chemical fibers to prepare modular greening materials. While the aforementioned technologies have achieved some success in general slope greening, they still have significant limitations: On the one hand, the vegetation mats of these technologies are relatively thin and have limited water retention capacity, making it difficult to provide plants with continuous water and fertilizer and sufficient root space when the base soil is barren or the slope is steep; on the other hand, some technologies (CN114600731A) use chemical fibers, which may pose a long-term risk of microplastic release, and most vegetation block / mat materials rely on high-temperature foaming or hot-melt molding processes, making it impossible to safely pre-bury seeds during the molding stage. Seeds can only be sprayed or broadcast after being laid on steep slopes, which is a cumbersome, time-consuming, and labor-intensive process. Seeds are also prone to falling off and being lost during transportation and construction, making it difficult to meet the engineering needs of rapid and stable greening in steep and freeze-thaw environments.

[0008] In summary, while existing vegetation mats and lightweight vegetation blocks have made some progress in water absorption and retention, weight reduction, and general slope ecological restoration, they still face core technical challenges in steep slopes in high-altitude and cold regions under the combined erosion of freeze-thaw cycles and hydraulic scouring. These challenges include structural instability, difficulty in maintaining water and fertilizer, poor vegetation suitability, and inconvenient construction. There is a lack of ecological vegetation materials that combine a block-like load-bearing structure, good freeze-thaw resistance, in-situ seed fixation, and water, heat, and fertilizer retention functions. Therefore, there is an urgent need for a freeze-thaw resistant vegetation block for steep slopes that can avoid high-temperature damage, utilize low-temperature physical properties to construct a high-performance microstructure, achieve permanent in-situ seed locking, and possess excellent freeze-thaw resistance. Summary of the Invention

[0009] The purpose of this invention is to address the technical problems of structural instability, difficulty in maintaining water and fertilizer, poor vegetation suitability, and inconvenient construction of ecological restoration materials on steep slopes in high-altitude and cold regions under the combined erosion of freeze-thaw cycles and hydraulic scouring. This invention provides a freeze-thaw resistant vegetation block for steep slopes and a green low-temperature freezing preparation method and application. Through collaborative innovations such as fiber reinforcement, cementation molding, plastic mesh embedding, and in-situ pre-embedding of seeds on the block surface, the invention achieves safe installation and long-term stable service of the vegetation block on steep slopes, and reliably fixes seeds on vertical or near-vertical slopes, resists erosion, and efficiently restores vegetation. This invention has significant engineering application value and promotional significance.

[0010] To achieve the above objectives, the present invention specifically adopts the following technical solution: A green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes includes the following steps: Step 1, prepare the matrix; The soil, organic matter, water-retaining agent, hydrothermal charcoal, and slow-release fertilizer are mixed to obtain the substrate.

[0011] The raw material components, by weight percentage, are: soil 58-68%, organic matter 30-40%, water-retaining agent 0.5-1.5%, hydrothermal carbon 0.5-1.5%, and slow-release fertilizer 0.5-1.5%.

[0012] The soil is a mixture of nutrient soil and garden soil, with the nutrient soil accounting for 42-58% of the total soil weight. The organic matter can be one or a combination of at least two of the following: pine needles, straw, humic acid, coconut coir, sawdust, rice husks, wood chips, and rice husks. The water-retaining agent can be one or a combination of at least two of the following: water-absorbing resin, potassium polyacrylate, starch graft copolymer, and acrylamide-based composite material. The slow-release fertilizer can be one or a combination of at least two of the following: resin-coated urea, urea-formaldehyde, magnesium ammonium phosphate, and modified attapulgite composite material.

[0013] Step 2: Construct a three-dimensional reinforced skeleton; Fibers are added to the matrix and dry-mixed to ensure uniform dispersion of the fibers within the matrix, resulting in a three-dimensional reinforced skeleton.

[0014] When adding fibers to the matrix, the weight of the fibers accounts for 4 to 20% of the weight of the matrix.

[0015] The fiber can be selected from one or a combination of at least two of hemp fiber, coconut fiber, and rock wool fiber.

[0016] Step 3, bonding and shaping; A polymer binder with freeze-thaw reinforcement properties is added to a three-dimensional reinforced skeleton and stirred to obtain a fluidized mixture.

[0017] The polymeric binder with freeze-thaw reinforcement properties is made of a 5-8% aqueous solution of polyvinylpyrrolidone, a 5-8% aqueous solution of polyethylene glycol, a 5-8% aqueous solution of polyvinyl alcohol, or a 5-8% aqueous solution of polyethylene oxide, and the weight of the polymeric binder with freeze-thaw reinforcement properties is 40-80% of the weight of the three-dimensional reinforced skeleton. Alternatively, it can be a combination of at least two of the above-mentioned aqueous solutions, and the total weight of the combined aqueous solution is 40-80% of the weight of the three-dimensional reinforced skeleton.

[0018] Step 4, layer-by-layer molding; First, a layer of fluidized mixture is laid in the mold and compacted, then an embedded reinforcing layer is laid, and finally another layer of fluidized mixture is filled in, compacted and leveled to obtain a planted block with a sandwich structure.

[0019] The embedded reinforcing layer can be a plastic mesh laid on the fluidized mixture, or it can be a non-woven fabric, geogrid, three-dimensional geonet, metal woven three-dimensional mesh, etc.

[0020] Step 5: Pre-bury and initially solidify the seeds; Plant seeds are sown on the surface of the planting block, and the seeds are partially or completely embedded in the surface matrix and fiber pores of the planting block by means of physical compression or spraying. This achieves in-situ pre-embedding of the seeds, resulting in a planting block pre-embedded with plant seeds.

[0021] When sowing plant seeds, the sowing rate is 20-40 g / m². 2 After evenly sowing plant seeds on the surface of the planting block, the seeds are moistened by squeezing or spraying to make them partially or completely embedded in the planting block.

[0022] Step 6: Low-temperature freezing; The plant blocks pre-embedded with plant seeds are subjected to low-temperature freezing treatment; during the freezing process, free water inside the plant blocks forms ice crystals, and a polymer binder with freeze-thaw enhancement properties forms a film.

[0023] The low-temperature freezing treatment method involves placing the plant blocks pre-embedded with plant seeds in an environment of -30 to -20°C for 24 to 36 hours. The cooling rate during the low-temperature freezing process is controlled at 1 to 5°C / min to induce the formation of uniformly distributed micron-sized ice crystals, preventing large ice crystals from piercing the seed coat or causing macroscopic cracking of the matrix. After the low-temperature freezing treatment, the plant blocks are interwoven with ice crystals and a binding agent film.

[0024] Step 7, demolding and consolidation; After freezing, the plant block is demolded and air-dried. During the air-drying process, the ice crystals melt into free water and evaporate, leaving interconnected microporous channels in situ. At the same time, the polymer binder with freeze-thaw enhancement properties continues to solidify into a film, resulting in a plant block with a porous skeleton structure inside.

[0025] The demolded plant blocks are then air-dried at room temperature for 20-24 hours. During this process, ice crystals melt into free water over a prolonged period, and the free water evaporates. Meanwhile, a polymer binder with freeze-thaw resistance continuously solidifies into a film, forming a porous framework structure within the plant block. This results in a stable, transportable, and assembleable plant block with a porous internal framework. The green low-temperature freezing preparation method for preparing high and steep slope resistant freeze-thaw resistant vegetation blocks is described above.

[0026] Application of the freeze-thaw resistant vegetation blocks for steep slopes in vegetation restoration and protection of steep slopes or rock retaining walls.

[0027] The beneficial effects of this invention are as follows: 1. In this invention, a fluid mixture is obtained by stirring a matrix, fiber, and binder. Seeds are pre-embedded and initially fixed in situ on the surface of the mixture. After low-temperature freezing, ice crystals and a film are formed inside the vegetation block. After air drying, a stable porous skeleton structure is formed inside the vegetation block, fixing the surface seeds in the micropores and fiber network of the vegetation block surface, thus fixing the seeds in situ. Compared with traditional direct spraying on slopes of ≥70°, the seeds in this vegetation block no longer rely on the slope friction for a short time to stay in place, but are "embedded" on the surface / layer of the vegetation block. Even during handling, transportation, and netting installation, they are not easy to fall off, fundamentally alleviating the problem of "not being able to stick and being easily washed away" when spraying seeds on high and steep slopes. The seeds are "embedded" in the surface of the vegetation block, with zero falling off during transportation, handling, and installation, and no secondary spraying is required on site.

[0028] 2. In this invention, through low-temperature freezing process and special binder compounding, the structure of the vegetation block remains intact after extreme freeze-thaw cycle simulation, the cohesion does not decrease but increases, the germination rate remains at a high level, and it also has a block-type load-bearing structure with good freeze-thaw resistance. Due to its internal porous skeleton structure, it has good water retention, heat preservation and fertilizer retention functions, which can realize the safe installation and long-term stable service of vegetation blocks on steep slopes, realize the reliable fixation of seeds on vertical or near-vertical slopes, resist erosion and achieve efficient vegetation restoration. It has significant engineering application value and promotion significance.

[0029] 3. In this invention, low-temperature physical molding is used instead of traditional high-temperature sintering or hot melting. The pre-embedded seed planting blocks are frozen at -30~-20℃ instead of traditional high-temperature hot pressing or drying molding, which effectively avoids heat damage to seed viability caused by high temperature. Moreover, the ice crystals formed during the freezing process melt and evaporate during the air drying process, transforming into interconnected pores, providing a loose, well-ventilated, water-retaining, heat-retaining, and fertilizer-retaining microenvironment for seed germination. Furthermore, the seeds are stably wrapped in a film-fiber skeleton, which is conducive to rapid water absorption, germination, and root penetration after arriving on site. In addition, energy consumption is reduced, and a large amount of agricultural waste (straw, pine needles) and biochar are used as raw materials, realizing the resource utilization of solid waste.

[0030] 4. In this invention, the matrix includes a lightweight porous framework constructed from organic matter and hydrothermal carbon. The gel network of water-retaining agent and cementing agent synergistically improves the water holding capacity of the plant block, and the slow-release fertilizer provides medium- and long-term nutrient supply, enabling the plant block to maintain a high water content and stable nutrient replenishment even under repeated freeze-thaw cycles and strong winds and radiation. At the same time, the porous matrix and fibrous framework have a certain heat preservation effect, providing an integrated microenvironment of "heat preservation, water retention, and fertilizer retention" for plant germination and early growth on steep slopes in cold and high-altitude areas.

[0031] 5. In this invention, lightweight components such as organic matter, hydrothermal carbon, and fibers are used. Through freeze molding and demolding and air drying, vegetation blocks with a large number of interconnected pores can be obtained. This makes the overall bulk density of the vegetation blocks significantly lower than that of conventional topsoil or sprayed vegetation layers. The individual blocks are also lighter, making them easier to handle manually, attach nets, and assemble on steep slopes. The porous structure and fiber channels provide ample growth and penetration channels for the roots. Plant roots can extend from the inside of the block into the original soil of the slope, enhancing the interlocking effect between the vegetation block and the bedrock or slope soil. This improves the overall stability and vegetation durability of steep slopes and facilitates manual assembly on steep slopes. Moreover, as the plants grow, the blocks gradually degrade and merge with the slope, achieving the highest ecological goal of "the blocks disappear, but the greenery remains forever." Attached Figure Description

[0032] Figure 1 A schematic diagram showing the germination and growth of seeds in plant blocks with different fiber contents after 7 days of growth; Among them, a contains 22% fiber, b contains 13% fiber, and c contains 4% fiber. Figure 2 A schematic diagram illustrating the water absorption capacity of plant blocks with different fiber contents; Figure 3 A schematic diagram illustrating the water retention capacity of plant blocks with different fiber contents; Figure 4 A schematic diagram showing the change in bulk density of plant blocks with different fiber contents under different freeze-thaw cycles; Figure 5 A schematic diagram illustrating the water retention capacity of plant blocks with different fiber contents under different freeze-thaw cycles; Figure 6 A schematic diagram showing the mechanical properties of plant blocks with different fiber contents under different freeze-thaw cycles; Figure 7 This is a schematic diagram illustrating the resilience of the planted block. Figure 8 A schematic diagram showing the greening situation of different vegetation blocks on the retaining wall; Figure 9 The cumulative runoff depth variation curves for vegetation blocks with different slopes are shown. Figure 10 This is a graph showing the cumulative soil erosion rate. Figure 11 The graph shows the runoff rate variation of vegetation blocks with different slopes. in addition, Figures 2-6 In this context, VB-4 represents a plant block with 4% fiber content, VB-13 represents a plant block with 13% fiber content, and VB-22 represents a plant block with 22% fiber content. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0034] Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] In this application, the high-steep slope resistant freeze-thaw vegetation block is prepared by using soil, organic matter, water-retaining agent, hydrothermal charcoal and slow-release fertilizer as the matrix, fiber as the reinforcing skeleton and mixing with binder. Through processes such as layering into mold, pre-burying and initially fixing seeds, low-temperature freezing and molding, and demolding and consolidation, a high-steep slope resistant freeze-thaw vegetation block suitable for installation on high-steep slopes is prepared.

[0036] Example 1 This embodiment provides a green low-temperature freezing preparation method for vegetation blocks resistant to strong freeze-thaw cycles on steep slopes, wherein the obtained vegetation blocks contain 22% coconut fiber. The preparation method includes the following steps: Step 1, prepare the matrix; Weigh out the soil, pine needles (organic matter), acrylamide-based composite material (water-retaining agent), and hydrothermal carbon and modified attapulgite composite material (slow-release fertilizer) in the specified proportions, mix them evenly, and obtain the matrix (the prepared matrix weighs more than 3000g). The above raw material components are listed as follows by weight percentage: The composition consists of 64% soil, 33% pine needles, 1% water-retaining agent, 1% hydrothermal charcoal, and 1% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with nutrient soil comprising 50% and garden soil comprising 50% by weight.

[0037] Weigh 3000g of the above matrix and add it to a mixing container for later use.

[0038] Step 2: Construct a three-dimensional reinforced skeleton; Add 660g of coconut fiber (accounting for 22% of the dry weight of the matrix) to a mixing container (which contains the matrix), and thoroughly dry mix the two to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0039] Step 3, bonding and shaping; A 6% polyvinyl alcohol aqueous solution (a binder, with the weight of the polyvinyl alcohol aqueous solution being 50% of the weight of the three-dimensional reinforced skeleton) is added to the three-dimensional reinforced skeleton and stirred to allow the binder to uniformly coat the soil particles, pine needles, and coconut fiber, resulting in a fluid mixture with certain plasticity and cohesiveness.

[0040] Step 4, layer-by-layer molding; First, lay a layer of fluidized material (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay a plastic mesh as an embedded reinforcing layer, and finally fill in the fluidized material, compact and level it to obtain a plant block with a sandwich structure.

[0041] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0042] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block at a rate of 30 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0043] Step 6: Low-temperature freezing; Planting blocks pre-embedded with seeds were placed in a -25℃ environment for 30 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the planting block surface and the network space composed of matrix-fiber-plastic mesh.

[0044] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed in room temperature for natural air drying for 22 hours. During the natural air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0045] Example 2 This embodiment provides a green low-temperature freezing preparation method for vegetation blocks resistant to strong freeze-thaw cycles on steep slopes, wherein the prepared vegetation blocks contain 13% coconut fiber. The preparation method includes the following steps: Step 1, prepare the matrix; Weigh out the soil, pine needles (organic matter), acrylamide-based composite material (water-retaining agent), and hydrothermal carbon and modified attapulgite composite material (slow-release fertilizer) in the specified proportions, mix them evenly, and obtain the matrix (the prepared matrix weighs more than 3000g). The above raw material components are listed as follows by weight percentage: The composition consists of 64% soil, 33% pine needles, 1% water-retaining agent, 1% hydrothermal charcoal, and 1% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with nutrient soil comprising 50% and garden soil comprising 50% by weight.

[0046] Weigh 3000g of the above matrix and add it to a mixing container for later use.

[0047] Step 2: Construct a three-dimensional reinforced skeleton; Add 390g of coconut fiber (13% of the dry weight of the matrix) to a mixing container (which contains the matrix) and mix them thoroughly to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0048] Step 3, bonding and shaping; A 6% polyvinyl alcohol aqueous solution (a binder, with the weight of the polyvinyl alcohol aqueous solution being 50% of the weight of the three-dimensional reinforced skeleton) is added to the three-dimensional reinforced skeleton and stirred to allow the binder to uniformly coat the soil particles, pine needles, and coconut fiber, resulting in a fluid mixture with certain plasticity and cohesiveness.

[0049] Step 4, layer-by-layer molding; First, lay a layer of fluidized material (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay a plastic mesh as an embedded reinforcing layer, and finally fill in the fluidized material, compact and level it to obtain a plant block with a sandwich structure.

[0050] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0051] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block at a rate of 30 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0052] Step 6: Low-temperature freezing; Planting blocks pre-embedded with seeds were placed in a -25℃ environment for 30 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the planting block surface and the network space composed of matrix-fiber-plastic mesh.

[0053] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed in room temperature for natural air drying for 22 hours. During the natural air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0054] Example 3 This embodiment provides a green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes, wherein the obtained vegetation blocks contain 4% coconut fiber. The preparation method includes the following steps: Step 1, prepare the matrix; Weigh out the soil, pine needles (organic matter), acrylamide-based composite material (water-retaining agent), and hydrothermal carbon and modified attapulgite composite material (slow-release fertilizer) in the specified proportions, mix them evenly, and obtain the matrix (the prepared matrix weighs more than 3000g). The above raw material components are listed as follows by weight percentage: The composition consists of 64% soil, 33% pine needles, 1% water-retaining agent, 1% hydrothermal charcoal, and 1% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with nutrient soil comprising 50% and garden soil comprising 50% by weight.

[0055] Weigh 3000g of the above matrix and add it to a mixing container for later use.

[0056] Step 2: Construct a three-dimensional reinforced skeleton; Add 120g of coconut fiber (4% of the dry weight of the matrix) to a mixing container (which contains the matrix), and thoroughly dry mix the two to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0057] Step 3, bonding and shaping; A 6% polyvinyl alcohol aqueous solution (a binder, with the weight of the polyvinyl alcohol aqueous solution being 50% of the weight of the three-dimensional reinforced skeleton) is added to the three-dimensional reinforced skeleton and stirred to allow the binder to uniformly coat the soil particles, pine needles, and coconut fiber, resulting in a fluid mixture with certain plasticity and cohesiveness.

[0058] Step 4, layer-by-layer molding; First, lay a layer of fluidized material (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay a plastic mesh as an embedded reinforcing layer, and finally fill in the fluidized material, compact and level it to obtain a plant block with a sandwich structure.

[0059] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0060] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block at a rate of 30 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0061] Step 6: Low-temperature freezing; Planting blocks pre-embedded with seeds were placed in a -25℃ environment for 30 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the planting block surface and the network space composed of matrix-fiber-plastic mesh.

[0062] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed in room temperature for natural air drying for 22 hours. During the natural air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0063] Example 4 This embodiment provides a green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes, the preparation method including the following steps: Step 1, prepare the matrix; Weigh out the soil, coconut coir (organic matter), potassium polyacrylate (water-retaining agent), hydrothermal charcoal, and urea-formaldehyde (slow-release fertilizer) in the specified proportions, mix them thoroughly, and obtain the substrate (the prepared substrate weighs more than 2500g). The above raw material components are listed as follows by weight percentage: The composition consists of 59.1% soil, 38.4% pine needles, 1.3% water-retaining agent, 0.6% hydrothermal charcoal, and 0.6% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with nutrient soil comprising 45% and garden soil comprising 55% by weight.

[0064] Weigh 2500g of the above matrix and add it to a mixing container for later use.

[0065] Step 2: Construct a three-dimensional reinforced skeleton; Add 125g of coconut fiber (5% of the dry weight of the matrix) to a mixing container (which contains the matrix), and thoroughly dry mix the two to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0066] Step 3, bonding and shaping; A 7% polyvinylpyrrolidone aqueous solution (a binder, with the weight of the polyvinylpyrrolidone aqueous solution being 45% of the weight of the three-dimensional reinforced skeleton) was added to the three-dimensional reinforced skeleton and stirred to allow the binder to uniformly coat the soil particles, pine needles, and coconut fiber, resulting in a fluid mixture with certain plasticity and cohesiveness.

[0067] Step 4, layer-by-layer molding; First, lay a layer of fluidized material (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay non-woven fabric as an embedded reinforcing layer, and finally fill in the fluidized material, compact and level it to obtain a plant block with a sandwich structure.

[0068] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0069] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block, with a seeding rate of 25 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0070] Step 6: Low-temperature freezing; Planting blocks pre-embedded with seeds were placed in a -28℃ environment for 28 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the planting block surface and the network space composed of matrix-fiber-plastic mesh.

[0071] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed in room temperature for natural air drying for 21 hours. During the natural air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0072] Example 5 This embodiment provides a green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes, the preparation method including the following steps: Step 1, prepare the matrix; Weigh out the soil, sawdust (organic matter), water-absorbing resin (water-retaining agent), hydrothermal charcoal, and resin-coated urea (slow-release fertilizer) in the specified proportions, mix them thoroughly, and obtain the matrix (the prepared matrix weighs more than 4000g). The above raw material components are listed as follows by weight percentage: The composition consists of 58.5% soil, 40% pine needles, 0.5% water-retaining agent, 0.5% hydrothermal charcoal, and 0.5% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with the nutrient soil accounting for 55% and the garden soil accounting for 45% by weight percentage.

[0073] Weigh 4000g of the above matrix and add it to a mixing container for later use.

[0074] Step 2: Construct a three-dimensional reinforced skeleton; Add 800g of coconut fiber (accounting for 20% of the dry weight of the matrix) to a mixing container (which contains the matrix), and thoroughly dry mix the two to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0075] Step 3, bonding and shaping; Add a 5% polyethylene glycol aqueous solution (binder, the weight of the added polyvinyl alcohol aqueous solution is 80% of the weight of the three-dimensional reinforced skeleton) to the three-dimensional reinforced skeleton and stir to make the binder uniformly coat the soil particles, pine needles and coconut fiber, so as to obtain a fluid mixture with certain plasticity and cohesion.

[0076] Step 4, layer-by-layer molding; First, lay a layer of fluidized mixture (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay a three-dimensional geonet as an embedded reinforcement layer, and finally fill in the fluidized mixture, compact and level it to obtain a planted block with a sandwich structure.

[0077] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0078] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block at a rate of 40 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0079] Step 6: Low-temperature freezing; Plant blocks pre-embedded with seeds were placed in a -30℃ environment for 24 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the plant block surface and the network space composed of matrix-fiber-plastic mesh.

[0080] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed at room temperature to air dry for 24 hours. During the air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0081] Example 6 This embodiment provides a green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes, the preparation method including the following steps: Step 1, prepare the matrix; Weigh out the following proportions: a mixture of soil, straw, and humic acid (organic matter; the mixing ratio can be determined according to actual conditions), starch graft copolymer (water-retaining agent), hydrothermal charcoal, and magnesium ammonium phosphate (slow-release fertilizer), and mix thoroughly to obtain the substrate (the prepared substrate weighs more than 2000g). The above raw material components are listed as follows by weight percentage: The composition consists of 60% soil, 35.5% pine needles, 1.5% water-retaining agent, 1.5% hydrothermal charcoal, and 1.5% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with nutrient soil comprising 51% and garden soil comprising 49% by weight.

[0082] Weigh 2000g of the above matrix and add it to a mixing container for later use.

[0083] Step 2: Construct a three-dimensional reinforced skeleton; Add 360g of coconut fiber (accounting for 18% of the dry weight of the matrix) to a mixing container (which contains the matrix), and thoroughly dry mix the two to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0084] Step 3, bonding and shaping; An 8% polyoxyethylene aqueous solution (a binder, with the weight of the polyvinyl alcohol aqueous solution being 40% of the weight of the three-dimensional reinforced skeleton) was added to the three-dimensional reinforced skeleton and stirred to allow the binder to uniformly coat the soil particles, pine needles, and coconut fiber, resulting in a fluid mixture with certain plasticity and cohesiveness.

[0085] Step 4, layer-by-layer molding; First, lay a layer of fluidized material (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay a metal woven three-dimensional mesh as an embedded reinforcing layer, and finally fill in the fluidized material, compact and level it to obtain a plant block with a sandwich structure.

[0086] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0087] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block at a rate of 20 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0088] Step 6: Low-temperature freezing; The pre-embedded seed-bearing blocks were placed in a -20℃ environment for 36 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the seed-bearing block surface and the network space composed of matrix-fiber-plastic mesh.

[0089] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed at room temperature to air dry for 20 hours. During the air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0090] Example 7 This embodiment provides a green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes, the preparation method including the following steps: Step 1, prepare the matrix; Weigh out the soil, rice husks (organic matter), a mixture of potassium polyacrylate and acrylamide-based composite material (water-retaining agent; the mixing ratio can be determined according to actual conditions), hydrothermal charcoal, and urea-formaldehyde (slow-release fertilizer) in the specified proportions, mix them evenly, and obtain the substrate (the prepared substrate weighs more than 3000g). The above raw material components are listed as follows by weight percentage: The composition consists of 59% soil, 37% pine needles, 1.2% water-retaining agent, 1.3% hydrothermal charcoal, and 0.5% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with nutrient soil accounting for 56% and garden soil accounting for 44% by weight.

[0091] Weigh 3000g of the above matrix and add it to a mixing container for later use.

[0092] Step 2: Construct a three-dimensional reinforced skeleton; Add 270g of coconut fiber (9% of the dry weight of the matrix) to a mixing container (which contains the matrix), and thoroughly dry mix the two to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0093] Step 3, bonding and shaping; A 6% polyvinylpyrrolidone aqueous solution (a binder, with the weight of the polyvinylpyrrolidone aqueous solution being 65% of the weight of the three-dimensional reinforced skeleton) was added to the three-dimensional reinforced skeleton and stirred to allow the binder to uniformly coat the soil particles, pine needles, and coconut fiber, resulting in a fluid mixture with certain plasticity and cohesiveness.

[0094] Step 4, layer-by-layer molding; First, lay a layer of fluidized mixture (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay geogrid as an embedded reinforcement layer, and finally fill in the fluidized mixture and compact and level it to obtain a planted block with a sandwich structure.

[0095] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0096] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block at a rate of 35 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0097] Step 6: Low-temperature freezing; Plant blocks pre-embedded with seeds were placed in a -22℃ environment for 32 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the plant block surface and the network space composed of matrix-fiber-plastic mesh.

[0098] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed in room temperature for natural air drying for 23 hours. During the natural air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0099] Example 8 This embodiment provides a green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes, the preparation method including the following steps: Step 1, prepare the matrix; Weigh out the following proportions: a mixture of soil, sawdust, and wood chips (organic matter; the mixing ratio can be determined according to actual conditions), potassium polyacrylate (water-retaining agent), hydrothermal charcoal, and a mixture of resin-coated urea and magnesium ammonium phosphate (slow-release fertilizer; the mixing ratio can be determined according to actual conditions). Mix thoroughly to obtain the substrate (the prepared substrate weighs more than 3500g). The above raw material components are listed as follows by weight percentage: The composition consists of 65.5% soil, 30% pine needles, 1.5% water-retaining agent, 1.5% hydrothermal charcoal, and 1.5% slow-release fertilizer. The soil is composed of nutrient soil and garden soil, with nutrient soil accounting for 47% and garden soil accounting for 53% by weight percentage.

[0100] Weigh 3500g of the above matrix and add it to a mixing container for later use.

[0101] Step 2: Construct a three-dimensional reinforced skeleton; Add 525g of coconut fiber (15% of the dry weight of the matrix) to a mixing container (which contains the matrix) and mix them thoroughly to ensure that the coconut fiber is evenly dispersed in the matrix (i.e., the soil-organic matter system) to obtain a three-dimensional reinforced skeleton.

[0102] Step 3, bonding and shaping; A mixture of polyethylene glycol aqueous solution and polyethylene oxide aqueous solution was added to the three-dimensional reinforced skeleton and stirred to uniformly coat the soil particles, pine needles, and coconut fiber with the binder, resulting in a fluid mixture with certain plasticity and adhesion. The concentrations of both the polyethylene glycol aqueous solution and the polyethylene oxide aqueous solution were 6%, and the weight of the mixture added was 45% of the weight of the three-dimensional reinforced skeleton.

[0103] Step 4, layer-by-layer molding; First, lay a layer of fluidized material (about half the height of the mold) in the mold (77cm long * 37cm wide * 5cm high), compact and level it, then lay a plastic mesh as an embedded reinforcing layer, and finally fill in the fluidized material and compact and level it to obtain a plant block with a sandwich structure.

[0104] The sandwich structure is a "upper matrix - middle mesh - lower matrix" sandwich structure.

[0105] Step 5: Pre-bury and initially solidify the seeds; Plant seeds were evenly sown on the surface of the layered planting block at a rate of 22 g / m². 2 Then squeeze or spray to moisten the plant seeds, so that the seeds are partially or completely embedded in the surface matrix and fiber pores of the plant block, thereby achieving in-situ pre-embedding and preliminary fixation of the seeds on the surface of the plant block, resulting in a plant block pre-embedded with plant seeds.

[0106] Step 6: Low-temperature freezing; The pre-embedded seed-bearing blocks were placed in a -24℃ environment for 34 hours of low-temperature freezing. During the freezing process, ice crystals were generated and a film was formed with the cementing agent, which further "locked" the plant seeds on the surface / surface layer into the micropores of the seed-bearing block surface and the network space composed of matrix-fiber-plastic mesh.

[0107] Step 7, demolding and consolidation; After freezing, the vegetation blocks are demolded and placed in room temperature for natural air drying for 21 hours. During the natural air drying process, the free water inside the vegetation blocks gradually evaporates, and the binder continues to solidify into a film, resulting in a stable, transportable, and assembleable vegetation block for steep slopes with a porous internal skeleton structure that is resistant to freeze-thaw cycles.

[0108] Test case This experiment uses plant blocks with different fiber contents prepared in Examples 1-3 to verify the various properties of the corresponding plant blocks.

[0109] I. Experimental Materials; Several plant blocks with fiber contents of 22%, 13% and 4% were obtained in Examples 1, 2 and 3, respectively.

[0110] II. Test Instruments; Electronic balance (0.01g accuracy, for sample mass determination), vernier calipers and graduated cylinders (for volume calculation), low-temperature freezing chamber or programmable high and low temperature test chamber (temperature range −30℃~25℃, for freeze forming and freeze-thaw cycles), constant temperature and humidity incubator (for controlling germination, growth and water retention environment), constant temperature and humidity chamber (for controlling evaporation environment in water retention tests), geotechnical direct shear tester (for shear strength determination), camera or mobile phone video recording equipment (for image recording of germination and growth process), constant temperature water bath (for dissolving adhesives), etc.

[0111] III. Experimental methods and results; 1. Observe the germination and growth of seeds from plant blocks with different fiber contents; Experimental method: The plant blocks prepared in Examples 1, 2, and 3 were placed in an environment of 25℃ and 60% humidity for natural germination and growth. After 7 days, the germination and growth of the seeds in each plant block were observed, and photos were taken and preserved.

[0112] Experimental results: One plant block each from those with fiber contents of 4%, 13%, and 22% was selected, and their seed germination and growth were as follows. Figure 1 As shown. From Figure 1 It can be seen that all three groups of planting blocks germinated 7 days after sowing, but the germination density and uniformity varied significantly with the fiber content: Group A (22% fiber) had high fiber coverage and insufficient substrate continuity, resulting in fewer and more scattered germination points; Group B (13% fiber) saw a significant increase in the number of germinations, but some local clustering still existed; Group C (4% fiber) had a more continuous and flat substrate, resulting in the densest and most uniform germination. Therefore, excessively high fiber content weakens effective seed-substrate contact and early water retention stability, hindering rapid and uniform establishment of the plant.

[0113] 2. Water absorption capacity test of plant blocks with different fiber contents; Experimental method: Ten plant blocks of each fiber content were selected, and the water absorption capacity of each plant block of each fiber content was measured (the measurement method is the existing technology).

[0114] Experimental results: The water absorption capacity of plant blocks with different fiber contents, such as Figure 2 As shown; from Figure 2It can be seen that the water absorption process of the plant block can be divided into three stages: "rapid water absorption - slow growth - reaching equilibrium". In the initial stage, the water absorption increases rapidly and becomes the main contributor to water absorption; in the middle stage, the growth rate decreases significantly; and in the later stage, water absorption basically reaches equilibrium. The overall water absorption capacity is as follows: 4% group (i.e., fiber content of 4%) > 13% group (i.e., fiber content of 13%) > 23% group (i.e., fiber content of 23%). The equilibrium water absorption at around 2400 minutes is approximately 1.6 g / g, 1.3 g / g, and 0.95 g / g, respectively (Note: g / g here refers to the water absorption of 1 g of plant block; for example, 1.6 g / g means that 1 g of plant block with a fiber content of 4% absorbs 1.6 g of water). This indicates that an increase in fiber content reduces the water absorption capacity and efficiency of the plant block, and excessive fiber is not conducive to the formation of a continuous and effective capillary water absorption and storage structure.

[0115] 3. Water retention capacity test of plant blocks with different fiber contents; Experimental method: Ten additional plant blocks of each fiber content were selected, and the water retention capacity of each fiber content plant block was measured (the measurement method is existing technology).

[0116] Experimental results: The water retention capacity of plant blocks with different fiber contents, such as Figure 3 As shown; from Figure 3 It can be seen that the water retention rate of all three groups of samples decreased continuously over time, showing an overall trend of "rapid decline in the early stage, gradual slowdown and entry into a low plateau in the later stage". Stable differences existed between different fiber contents: the 4% group (i.e., fiber content of 4%) had the highest water retention rate and the slowest decline throughout the entire period, the 13% group was in the middle, and the 22% group had the lowest and fastest decline. The differences were mainly concentrated in the early and middle stages (approximately 20–100 hours). Although all groups tended to stabilize in the later stages, the 4% group still maintained a higher residual water retention level. This indicates that excessively high fiber content accelerates water loss and weakens water retention stability, while lower fiber content is more conducive to maintaining continuous water storage / capillary structure, thereby improving the ability to resist evaporation and retain water.

[0117] 4. Test on the change in bulk density of plant blocks with different fiber contents under different freeze-thaw cycles; Experimental method: Twenty additional plant blocks of each fiber content were selected, and each type of plant block was subjected to 0, 3, 6, and 9 freeze-thaw cycles (e.g., for 20 plant blocks with a fiber content of 4%, 5 were subjected to 0 freeze-thaw cycles, 5 to 3, 5 to 6, and the remaining 5 to 9; the same applies to plant blocks with fiber contents of 13% and 22%). The change in bulk density of plant blocks with different fiber contents under different freeze-thaw cycles was measured (the measurement method is based on existing technology).

[0118] Experimental results: Changes in bulk density of plant blocks with different fiber contents under different freeze-thaw cycles, such as... Figure 4 As shown; from Figure 4 It can be seen that the bulk density of the planted blocks is mainly controlled by the fiber content. The 4% fiber group has the highest bulk density, followed by the 13% group, and the 22% group has the lowest. This indicates that increasing the fiber content significantly improves the porosity and achieves lightweighting. Under the same fiber content, as the number of freeze-thaw cycles increases from 0 to 3 / 6 / 9, the bulk density only decreases slightly, and the ranking of each group remains unchanged. This indicates that freeze-thaw action mainly causes slight structural loosening / pore enlargement, but the overall change is limited, and the planted blocks have a certain degree of freeze-thaw stability.

[0119] 5. Water retention capacity test of plant blocks with different fiber contents under different freeze-thaw cycles; Experimental method: Twenty additional plant blocks of each fiber content were selected, and each type of plant block was subjected to 0, 3, 6, and 9 freeze-thaw cycles (e.g., for 20 plant blocks with a fiber content of 4%, 5 were subjected to 0 freeze-thaw cycles, 5 to 3, 5 to 6, and the remaining 5 to 9; the same applies to plant blocks with fiber contents of 13% and 22%). The 24-hour water retention capacity of plant blocks with different fiber contents under different freeze-thaw cycles was measured (the measurement method is based on existing technology).

[0120] Experimental results: The 24-hour water retention capacity of plant blocks with different fiber contents under different freeze-thaw cycles, such as... Figure 5 As shown; from Figure 5 It can be seen that the water retention capacity of the plant blocks under freeze-thaw cycles generally shows a slight downward trend, but the differences between groups are mainly determined by fiber content: at any freeze-thaw cycle, the 4% group has the highest water retention capacity, the 13% group is in the middle, and the 22% group has the lowest. As the number of freeze-thaw cycles increases from 0 to 3 / 6 / 9, the water retention capacity of each group only shows a limited decrease, and the ranking remains unchanged, indicating that the frozen-formed plant blocks have a certain degree of freeze-thaw stability; at the same time, a higher fiber content is not conducive to maintaining a continuous and effective water storage structure, and is more likely to lead to a decrease in water retention capacity under freeze-thaw cycles.

[0121] 6. Mechanical properties (cohesion, also known as adhesion) test of plant blocks with different fiber contents under different freeze-thaw cycles; Experimental method: Twenty additional plant blocks of each fiber content were selected, and each type of plant block was subjected to 0, 3, 6, and 9 freeze-thaw cycles (e.g., for 20 plant blocks with a fiber content of 4%, 5 were subjected to 0 freeze-thaw cycles, 5 to 3, 5 to 6, and the remaining 5 to 9; the same applies to plant blocks with fiber contents of 13% and 22%). The cohesion of plant blocks with different fiber contents under different freeze-thaw cycles was measured (the measurement method is based on existing technology).

[0122] Experimental results: Mechanical properties of plant blocks with different fiber contents under different freeze-thaw cycles, such as... Figure 6 As shown; from Figure 6 It can be seen that after 0, 3, 6, and 9 freeze-thaw cycles, the cohesion of the three groups of planted blocks did not decrease; on the contrary, it showed an overall upward trend. This indicates that the freeze-formed structure can strengthen the bonding between particles, fibers, and cementitious phases under freeze-thaw action. Among different fiber contents, the 13% group consistently had the highest cohesion, followed by the 22% group, and the 4% group had the lowest. Moreover, the increase was more significant in the early freeze-thaw cycles (0 to 3 / 6 cycles) and tended to level off in the later stages (6 to 9 cycles). This suggests that a moderate fiber content is more conducive to forming a stable structure with effective "bridging reinforcement + cementation consolidation," thereby obtaining better freeze-thaw shear stability.

[0123] 7. Toughness test of the planted block; Experimental method: Ten plant blocks of each fiber content were selected, and the toughness of each plant block of each fiber content was measured (the measurement method is the existing technology).

[0124] Test method: The testers used both hands to squeeze and one hand to squeeze, respectively (the methods are as follows). Figure 7 (As shown).

[0125] in conclusion: Figure 7 Only two 13% fiber content planted blocks were demonstrated to achieve significant bending deformation under external force (two hands, one hand), while maintaining overall continuity and integrity without brittle fracture or obvious cracking. No significant peeling was observed at the edges or center of the material during bending, indicating that the internal fiber skeleton and matrix are bonded together to form an effective toughening structure. This characteristic demonstrates that the planted blocks possess good flexibility and flexural strength, making them suitable for construction, handling, and application to irregular substrates.

[0126] 8. Germination test of plant blocks with different fiber contents on retaining walls; Experimental method: Nine planting blocks of each fiber content were selected and attached to the retaining wall. Germination was measured on the day of attachment, 15 days, 30 days and 60 days (the measurement method is the existing technology).

[0127] Conclusion: Germination of plant blocks with different fiber contents on retaining walls, such as... Figure 8 As shown; from Figure 8As can be seen from the photos of the wall test, all three groups of vegetation blocks achieved seedling emergence and growth on the vertical surface, but there were significant differences in vegetation coverage, uniformity, and sustained growth stability. The 4% group had formed a relatively continuous seedling zone after 30 days, with a more uniform distribution, indicating good substrate continuity, easy seed contact with the substrate, and a relatively stable water supply. However, sparse areas were still visible in some places, and the overall coverage was slightly lower than the 13% group. The 13% group showed denser seedling emergence and stronger connectivity after 30 days. A magnified area showed a more uniform seedling distribution and lower patchiness, indicating that the medium fiber content achieved a better balance between water retention, aeration, and skeletal support: providing sufficient porosity and fiber bridging to resist vertical gravitational slippage without disrupting the continuous coverage of the fine-particle substrate, thus facilitating the rapid formation of a stable green layer. In contrast, while 22% of the group had emerged by 30 days, the seedlings were still sparse and patchy. Localized fiber aggregation and substrate discontinuity may have reduced seed fixation and inconsistent water supply, hindering rapid and uniform planting on vertical surfaces. Overall, the 13% group showed the best early-stage greening effect on the wall.

[0128] 9. Water erosion resistance test of vegetation blocks on different slopes; Experimental Method: Test plots with slopes of 45°, 60°, and 75° were set up on an indoor rainfall simulation device. A 60-minute rainfall scour test was conducted under the same rainfall intensity of 50 mm / h. Slope runoff was continuously collected during the experiment, and the runoff duration and flow rate changes were recorded. The runoff samples were separated and weighed for sediment separation. Cumulative runoff depth, cumulative soil loss, and runoff coefficient were calculated to obtain the desired results. Figures 9-11 The variation curves shown and the erosion parameters shown in Table 1 are used to characterize the differences in runoff and sediment production and erosion response under different slopes. Table 1 Erosion parameters

[0129] Under the same rainfall intensity (50 mm / h) and rainfall duration (60 min), the amplification effect of slope on the "runoff generation" process is very significant: for example Figure 9 As shown in Table 1, the cumulative runoff depth increases significantly with increasing slope (from 45° to 75°); the erosion parameter also rises rapidly from 0.22 to 0.99, indicating that slope infiltration is relatively limited, runoff is more easily connected, a larger proportion of rainfall is converted into surface runoff, and the driving force of erosion is thus enhanced. Figure 11As shown, the runoff rate process also exhibits a faster initial rise and higher peak on steep slopes, followed by a gradual decline and stabilization, reflecting a typical response of "rapid confluence – later stabilization". In contrast, total sediment yield and erosion intensity increase with slope, and the cumulative soil loss curve rises rapidly in the initial stage of rainfall, then plateaus, indicating that sediment output is mainly concentrated in the initial stage (mobile fine particles / surface loose matter are rapidly carried away), and then gradually transitions to "sediment supply limitation" under the protection of cover / structure, making it difficult for sustained strong erosion to occur. Overall, increased slope improves runoff connectivity and increases erosion risk, but the cumulative soil loss in the experiment remained at a low level (all <0.001 g / cm², such as...). Figure 10 As shown in the figure, this demonstrates that the slope cover system has a strong ability to resist erosion and suppress continuous water erosion.

[0130] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes, characterized in that, Includes the following steps: Step 1, prepare the matrix; The soil, organic matter, water-retaining agent, hydrothermal charcoal, and slow-release fertilizer are mixed to obtain the substrate; Step 2: Construct a three-dimensional reinforced skeleton; Fibers are added to the matrix and dry-mixed, and the fibers are dispersed in the matrix to obtain a three-dimensional reinforced skeleton. Step 3, bonding and shaping; A polymer binder with freeze-thaw reinforcement properties was added to a three-dimensional reinforced skeleton and stirred to obtain a fluidized mixture. Step 4, layer-by-layer molding; First, a layer of fluid mixture is laid in the mold and compacted, then an embedded reinforcing layer is laid, and finally the fluid mixture is filled in and compacted and leveled to obtain a planted block with a sandwich structure. Step 5: Pre-bury and initially solidify the seeds; Plant seeds are sown and embedded on the surface of the vegetation block to obtain a vegetation block pre-embedded with plant seeds; Step 6: Low-temperature freezing; The plant blocks pre-embedded with plant seeds are subjected to low-temperature freezing treatment; during the freezing process, free water inside the plant blocks forms ice crystals, and a polymer binder with freeze-thaw enhancement properties forms a film. Step 7, demolding and consolidation; After freezing, the planted blocks are demolded and air-dried. During the air-drying process, the ice crystals melt into free water and evaporate, while the polymer binder with freeze-thaw enhancement properties continues to solidify into a film. Finally, a planted block with a porous skeleton structure is obtained.

2. The green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes as described in claim 1, characterized in that: In the matrix of step 1, the raw material components are expressed as a percentage by weight: Soil 58-68%, organic matter 30-40%, water-retaining agent 0.5-1.5%, hydrothermal carbon 0.5-1.5%, slow-release fertilizer 0.5-1.5%.

3. The green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes as described in claim 1, characterized in that: In step 2, when adding fibers to the matrix, the weight of the fibers is 4 to 20% of the weight of the matrix.

4. The green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes as described in claim 1, characterized in that: In step 3, the polymeric binder with freeze-thaw strengthening properties is one or a combination of at least two of the following: polyvinylpyrrolidone aqueous solution, polyethylene glycol aqueous solution, polyvinyl alcohol aqueous solution, and polyethylene oxide aqueous solution.

5. The green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes as described in claim 1, characterized in that: In step 3, the weight of the polymer binder with freeze-thaw reinforcement properties is 40-80% of the weight of the three-dimensional reinforced skeleton, and the concentration of the polymer binder with freeze-thaw reinforcement properties is 5-8%.

6. The green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes as described in claim 1, characterized in that: In step 5, when sowing plant seeds on the surface of the vegetation block, the sowing rate is 20-40 g / m². 2 .

7. The green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks on steep slopes as described in claim 1, characterized in that: In step 6, the low-temperature freezing treatment method is as follows: place the plant block pre-buried with plant seeds in a low-temperature freezing environment of -30~-20℃ for 24~36 hours.

8. The green low-temperature freezing preparation method for freeze-thaw resistant vegetation blocks for steep slopes as described in claim 1, characterized in that: In step 7, the demolded plant blocks are placed in room temperature and air-dried naturally for 20-24 hours.

9. The high-steep slope resistant freeze-thaw resistant vegetation block prepared by the green low-temperature freezing preparation method according to any one of claims 1-8.

10. The application of the freeze-thaw resistant vegetation block for steep slopes as described in claim 9 in vegetation restoration and protection of steep slopes or rock retaining walls.

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