Ecological restoration method for high and steep slope in cold and arid region

Abstract

The application discloses a kind of cold arid region high and steep slope ecological restoration method, it is related to slope ecological restoration technical field, including cleaning and leveling slope surface to be repaired, after setting primary and secondary anchor rod, lower CF network, water storage tank rigid phytogenic stick and upper layer iron wire protective net are fixed in turn, three-dimensional anti-slide water storage net pad is constructed;After spraying 10-15cm thick high fixation modified bottom layer substrate, layered spraying group building mixed sowing and fast-growing shallow root system mixed sowing two kinds of surface layer substrate, form double formula grass seed layer;Finally, cover non-woven fabric and carry out gradient watering maintenance in stages;The application is constructed three-dimensional anti-slide water storage net pad structure, cooperate with high fixation substrate formula and layered double formula grass seed system, realize high and steep slope surface substrate stable fixation, long-acting water storage, substantially reduce maintenance frequency, form the stable xerophytic vegetation community that adapts to cold arid region.

Description

Technical Field

[0001] This invention relates to the field of slope ecological restoration technology, specifically to a method for ecological restoration of steep slopes in cold and arid regions. Background Technology

[0002] During the construction of water conservancy and hydropower projects in the cold and arid northern regions, a large number of steep excavated slopes are formed. Shotcrete is often used in these projects to reinforce and stabilize the slopes. These shotcrete slopes generally have the characteristics of drought and water shortage, poor soil, and large temperature difference in high altitude and cold regions, making ecological restoration and revegetation urgently needed.

[0003] Currently, for steep slopes with a gradient greater than 45° and a height greater than 20m, the conventional method of directly covering with soil or spraying soil after wire mesh installation suffers from insufficient substrate adhesion, making it prone to overall slippage and erosion. Thick-layer substrate wire mesh spraying technology has limited substrate thickness, while vegetation concrete spraying technology has high porosity and poor water retention. Furthermore, the concrete surface layer prevents plant roots from penetrating the underlying rock mass, hindering water and mineral exchange between the roots and the rock layer. This results in the substrate layer being chronically arid and water-deficient, requiring frequent watering and maintenance year-round, leading to high operating costs and difficulty in guaranteeing vegetation survival rates and community stability.

[0004] In terms of grass seed configuration and substrate performance, existing hydroseeding technologies mostly adopt single grass seed formulations and single-layer hydroseeding modes, which make it difficult to balance rapid surface coverage and erosion prevention in the early stage with long-term community stability in the later stage. They cannot meet the stringent growth requirements of drought resistance, cold resistance, and poor soil tolerance in cold and arid regions. Hydroseeding substrates generally have difficulty balancing erosion resistance and adhesion with the porosity and permeability required for seed germination. Either the adhesion is insufficient and easily washed away by rainwater, or the consolidation is too strong and inhibits root growth, which further restricts the ecological restoration effect of high and steep slopes in cold and arid regions. Summary of the Invention

[0005] The purpose of this invention is to provide an ecological restoration method for steep slopes in cold and arid regions, in order to solve the problems of easy slippage and loss of substrate, weak water and fertilizer retention capacity, and poor vegetation community stability in existing restoration technologies for steep sprayed concrete slopes in cold and arid regions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for ecological restoration of steep slopes in cold and arid regions, comprising the following steps:

[0007] S1. Remove dangerous rocks and debris from the steep slope surface to be repaired, and complete the slope leveling;

[0008] S2. Install anchor rods on the leveled slope to fix the lower CF net, water storage trough-shaped rigid vegetation rod and upper wire mesh in sequence to form a three-dimensional anti-sliding water storage net mat structure.

[0009] S3. Spray a highly adhesive modified base material onto the slope of the erected net mat to form a base material layer with a thickness of 10-15cm.

[0010] S4. On the surface of the bottom substrate layer, spray the mixed seeding substrate for establishing groups and the mixed seeding substrate for fast-growing shallow roots one after the other to form a double-formula grass seed layer for the surface substrate.

[0011] S5. Cover the slope with non-woven fabric and water it in stages to complete the slope vegetation establishment.

[0012] Furthermore, in step S2, the pore size of the lower CF mesh is 50-100mm, and the pore size of the upper wire mesh is 50mm; the water storage trough-shaped rigid planting rods are arranged in strips at intervals along the slope and fixed between the two meshes, with a diameter of 80-100mm.

[0013] Furthermore, the rigid planting stick in the water storage tank is filled with erosion-resistant flexible fibers, biochar, planting soil and water-retaining materials, which are used to slowly release nutrients and moisture to the substrate layer within a 20-30cm radius around the plant through capillary action.

[0014] Further, in step S3, by weight, the highly adhesive modified substrate is made by mixing 1.5 parts water, 1.5 to 2.5 parts planting soil, 1 part organic fiber and 0.2 to 0.3 parts highly adhesive greening additive;

[0015] The high-fixation greening additive is an organic-inorganic composite gel formed by cross-linking reaction of two groups of organic colloids (A and B), slow-release fertilizer, biochar, and binder.

[0016] Further, in step S4, the surface substrate of the dual-formulation grass seed layer is, by weight, a mixture of 1 part water, 0.5 parts planting soil, 0.5 parts organic fiber, and 0.5 parts organic fertilizer and microbial agent; the total amount of grass seeds added to the surface substrate is 0.5-1 kg / m². 3 .

[0017] Furthermore, in step S4, a 2cm thick layer of the cohort-building mixed-sowing substrate is first sprayed, followed by a 1cm thick layer of the fast-growing shallow-root mixed-sowing substrate.

[0018] The fast-growing, shallow-rooted mixed-sowing formula includes *Solanum nigrum*, *Cephalotaxus fortunei*, *Acer negundo*, dandelion, and sweet clover; the group-building mixed-sowing formula includes *Cephalotaxus fortunei*, *Leymus chinensis*, *Symplocos edulis*, *Caragana korshinskii*, and *Astragalus membranaceus*.

[0019] Furthermore, in step S5, the method of carrying out watering and maintenance in stages is as follows:

[0020] Water every 2-3 days for 2 weeks after spraying to promote seed germination;

[0021] Water every 10 to 15 days for 1 to 3 months after spraying to ensure seedling survival;

[0022] During the growing season three months after hydroseeding, water once a month, with a single watering volume of 4-5 L / m². 2 .

[0023] Furthermore, in step S2, the anchor bolts include main anchor bolts and secondary anchor bolts, which are alternately arranged and are all laid along the slope to fix the two layers of netting and the water storage trough-shaped rigid vegetation rods.

[0024] The main anchor bolt has a diameter of 16mm and a length of 1 to 1.2m; the secondary anchor bolt has a diameter of 12mm and a length of 0.8m.

[0025] Compared with existing technologies, this invention provides a method for ecological restoration of steep slopes in cold and arid regions. It achieves low-maintenance ecological restoration through a three-dimensional anti-sliding water-retaining mat system and a matching hydroseeding process. The system relies on a lower layer of CF mesh, water-retaining trough-shaped rigid vegetation rods, and an upper layer of wire mesh to construct a three-dimensional mat structure. This forms a strip-shaped reinforcing belt on the slope surface to support the substrate, increasing the substrate layer thickness to 10-15cm, effectively preventing the substrate from sliding down steep slopes and making it suitable for steep slope construction conditions. The vegetation rods are filled with erosion-resistant flexible fibers, biochar, and water-retaining materials, which can slowly release water and fertilizer within a 20-30cm radius through capillary action, forming a strip-shaped dominant propagation zone. Combined with a drought-tolerant grass seed formula, after three months of vegetation establishment, only monthly maintenance is required during the growing season, and once a year in spring thereafter to ensure successful vegetation regrowth, significantly reducing operation and maintenance costs. Simultaneously, a dual-formula spraying mode is adopted, combining fast-growing, shallow-rooted pioneer species with native community-building species, which balances rapid surface coverage and erosion reduction with long-term community stability, making it suitable for the harsh site conditions of arid and barren areas in cold and dry regions. The bottom substrate uses an organic-inorganic composite gel system, which has both high adhesion and erosion resistance and suitable porosity, fully ensuring the aeration requirements for seed germination and root growth. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0027] Figure 1 This is a schematic cross-sectional view of the three-dimensional anti-slip water-retaining net mat hydroseeding and grass planting structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the water storage tank-shaped rigid planting rod structure of the present invention;

[0029] Figure 3 These are real-world images illustrating the application status of vegetation establishment at various stages, as provided in embodiments of the present invention; wherein, Figure 3 A is a real-world image of the target slope surface clearing; Figure 3 B is a real-life image showing the completion of the three-dimensional anti-sliding water-retaining net mat installation on the slope, the implementation of substrate spraying operations, and the covering with non-woven fabric for moisture retention and protection. Figure 3 C is a close-up view of the slope substrate and non-woven fabric covering in the early stage after hydroseeding; Figure 3 D is a real-life image of seedling germination and initial greening of the slope during the gradient maintenance stage; Figure 3 E is a real-life image of the slope fully covered with non-woven fabric for maintenance. Figure 3 F is a real-life image of the slope after the vegetation has grown stably and the non-woven fabric has gradually degraded.

[0030] Figure 4 This is a diagram showing the state of vegetation establishment and application three years after the present invention. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] Example:

[0033] This embodiment is applied to a steep, moderately weathered slate slope with sprayed concrete in a cold and arid region of northern China. The slope angle is 80° and the slope height is greater than 20m. The ecological restoration method of this invention is used, and the specific steps are as follows:

[0034] Step 1: Thoroughly clean the target slope surface, remove dangerous rocks, loose stones and various debris, repair protruding and sunken parts of the slope surface, and complete the slope surface leveling treatment to provide a regular working base for subsequent netting installation and substrate spraying.

[0035] Step 2: Install anchor bolts on the leveled slope. The anchor bolts are divided into main anchor bolts and secondary anchor bolts, which are installed alternately. The main anchor bolts have a diameter of 16mm and a length of 1 to 1.2m, while the secondary anchor bolts have a diameter of 12mm and a length of 0.8m. The anchor bolts penetrate deep into the rock mass of the slope to provide a stable anchoring force.

[0036] After the anchor bolts are installed, the lower layer of CF mesh is fixed first, with the mesh pore size controlled at 50-100mm. Then, rigid vegetation rods in the shape of water storage troughs are fixed horizontally along the slope surface on the surface of the lower layer of CF mesh in a strip-like pattern, with the diameter of the vegetation rods being 80-100mm. Finally, an upper layer of wire mesh is fixed on the outside of the vegetation rods, with the mesh size of the wire mesh being 50mm. The two layers of mesh and the vegetation rods in the middle together form a three-dimensional anti-sliding water storage net mat structure, shaping a noodle-like micro-topography on the slope and creating a local micro-environment with strong water storage capacity.

[0037] The rigid planting sticks, shaped like water storage troughs, are filled with erosion-resistant flexible fibers, biochar, planting soil, and water-retaining materials. The planting sticks can be firmly fixed between two layers of netting. The water-retaining materials and nutrients inside can slowly release water and nutrients to the substrate layer within a 20-30cm radius around the planting sticks through capillary action, forming a dominant breeding zone with high water content on both sides of the planting sticks. This prioritizes the establishment of grass hedges and reduces slope erosion.

[0038] Step 3: Prepare the highly adhesive modified base substrate. The raw material ratio by weight is: 1.5 parts water, 1.5-2.5 parts planting soil, 1 part organic fiber, and 0.2-0.3 parts highly adhesive greening additive. The highly adhesive greening additive uses two groups of organic colloids, A and B. After uniformly mixing the slow-release fertilizer, biochar, and binder, a cross-linking reaction occurs, forming an organic-inorganic composite gel with properties of slow release, water retention, air permeability, anti-evaporation, granulation, and high viscosity. The prepared base substrate is sprayed onto the slope where the netting has been erected using a hydroseeding device, forming a base substrate layer with a thickness of 10-15 cm. The strip-shaped reinforcing structure of the three-dimensional netting effectively supports the substrate, preventing it from sliding down and falling, ensuring the thickness and structural stability of the substrate layer.

[0039] Step 4: Construct a dual-formula grass seed layer for the surface substrate. The surface substrate is prepared by weight as follows: 1 part water, 0.5 parts planting soil, 0.5 parts organic fiber, and 0.5 parts organic fertilizer and microbial agent. Mixed grass seeds are added to the surface substrate, with a total seed addition of 0.5–1 kg / m². 3 .

[0040] Grass varieties that are drought-resistant, cold-resistant, salt-tolerant, and tolerant of poor soil were selected and divided into two groups of mixed sowing formulas, as shown in the table below:

[0041]

[0042] The fast-growing, shallow-rooted mixed-sowing formula contains 1g / m² of *Polygonum multiflorum*. 2 1g / m 2 1g / m 2 Dandelion 0.5g / m 2 Sweet clover 0.2g / m 2 ;

[0043] The formula for creating a mixed broadcast group contains 3g / m² of ice plant. 2 Leymus chinensis 4g / m 2 Pearl firewood 2g / m 2 5g / m 2 Astragalus membranaceus 2g / m 2 .

[0044] The hydroseeding process employs a layered approach: first, a 2cm thick layer of mixed seed formulation for establishing a population is sprayed, followed by a 1cm thick layer of fast-growing, shallow-rooted mixed seed formulation for the surface layer, ultimately forming a double-formula grass seed layer for the surface layer.

[0045] The two layers of seeds are buried at different depths, resulting in differences in germination and growth rates: fast-growing, shallow-rooted grass seeds can quickly grow and cover the slope, reducing rainwater erosion; perennial, community-building grass seeds are gradually planted and grow, eventually forming a stable and lasting xerophytic vegetation community.

[0046] Step 5: After the hydroseeding operation is completed, cover the entire slope with non-woven fabric for moisture retention and protection, and adopt a phased gradient watering maintenance system:

[0047] Within two weeks after hydroseeding, water every 2 to 3 days to ensure the water needed for seed germination and promote seed germination and full seedling emergence.

[0048] Water the seedlings every 10 to 15 days for 1 to 3 months after spraying to ensure their survival and normal growth.

[0049] During the growing season three months after hydroseeding, water once a month, with a single watering volume of 4-5 L / m². 2 This can meet the growth needs of drought-tolerant vegetation.

[0050] Using the method of this embodiment, the vegetation coverage rate can reach more than 40% after one month of spraying, and the vegetation can be quickly restored and the landscape effect can be achieved in 2 to 3 months. After the vegetation establishment period ends in the same year, high-frequency maintenance can be stopped, and only one maintenance is needed every spring to ensure that the vegetation can quickly turn green again, thus achieving low-maintenance ecological restoration of high and steep slopes in cold and arid areas.

[0051] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for ecological restoration of steep slopes in cold and arid regions, characterized in that, Includes the following steps: S1. Remove dangerous rocks and debris from the steep slope surface to be repaired, and complete the slope leveling; S2. Install anchor rods on the leveled slope to fix the lower CF net, water storage trough-shaped rigid vegetation rod and upper wire mesh in sequence to form a three-dimensional anti-sliding water storage net mat structure. S3. Spray a highly adhesive modified base substrate onto the slope of the erected netting to form a base substrate layer with a thickness of 10-15cm. S4. On the surface of the bottom substrate layer, spray the mixed seeding substrate for establishing groups and the mixed seeding substrate for fast-growing shallow roots one after the other to form a double-formula grass seed layer for the surface substrate. S5. Cover the slope with non-woven fabric and water it in stages to complete the slope vegetation establishment.

2. The method for ecological restoration of steep slopes in cold and arid regions according to claim 1, characterized in that, In step S2, the pore size of the lower CF mesh is 50-100mm, and the pore size of the upper wire mesh is 50mm; the water storage trough-shaped rigid planting rods are arranged in strips along the slope and fixed between the two meshes, with a diameter of 80-100mm.

3. The method for ecological restoration of steep slopes in cold and arid regions according to claim 2, characterized in that, The rigid planting stick in the water storage tank is filled with erosion-resistant flexible fiber, biochar, planting soil and water-retaining material, which is used to slowly release nutrients and moisture to the substrate layer within a range of 20-30cm around it through capillary action.

4. The method for ecological restoration of steep slopes in cold and arid regions according to claim 1, characterized in that, In step S3, the highly fixed modified substrate is made by mixing 1.5 parts water, 1.5 to 2.5 parts planting soil, 1 part organic fiber and 0.2 to 0.3 parts highly fixed greening additive by weight. The high-fixation greening additive is an organic-inorganic composite gel formed by cross-linking reaction of a mixture of two groups of organic colloids (A and B), slow-release fertilizer, biochar, and binder.

5. The method for ecological restoration of steep slopes in cold and arid regions according to claim 1, characterized in that, In step S4, the surface substrate of the dual-formulation grass seed layer is, by weight, a mixture of 1 part water, 0.5 parts planting soil, 0.5 parts organic fiber, and 0.5 parts organic fertilizer and microbial agent; the total amount of grass seeds added to the surface substrate is 0.5-1 kg / m². 3 .

6. The method for ecological restoration of steep slopes in cold and arid regions according to claim 5, characterized in that, In step S4, a 2cm thick layer of the mixed seeding substrate is first sprayed, followed by a 1cm thick layer of the fast-growing shallow-root mixed seeding substrate. The fast-growing, shallow-rooted mixed-sowing formula includes *Solanum nigrum*, *Cephalotaxus fortunei*, *Acer negundo*, dandelion, and sweet clover; the group-building mixed-sowing formula includes *Cephalotaxus fortunei*, *Leymus chinensis*, *Symplocos edulis*, *Caragana korshinskii*, and *Astragalus membranaceus*.

7. The method for ecological restoration of steep slopes in cold and arid regions according to claim 1, characterized in that, In step S5, the method of watering and maintaining the plant in stages is as follows: Water every 2-3 days for 2 weeks after spraying to promote seed germination; Water every 10 to 15 days for 1 to 3 months after spraying to ensure seedling survival; During the growing season three months after hydroseeding, water once a month, with a single watering volume of 4-5 L / m². 2 .

8. The method for ecological restoration of steep slopes in cold and arid regions according to claim 1, characterized in that, In step S2, the anchor bolts include main anchor bolts and secondary anchor bolts, which are alternately arranged and are all laid along the slope to fix the two layers of netting and the water storage trough-shaped rigid vegetation rods. The main anchor bolt has a diameter of 16mm and a length of 1 to 1.2m; the secondary anchor bolt has a diameter of 12mm and a length of 0.8m.

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