A scour-resistant grass planting system for a hydro-fluctuation belt, a preparation method and application, and a method for repairing damaged ecological system in steep slope area of hydro-fluctuation belt

Abstract

The present application belongs to the field of ecological restoration technology, and particularly relates to a composite grass planting system, a preparation method and application, and a damaged ecological system restoration method for lake and reservoir drawdown belt steep slope areas. The composite grass planting blanket provided by the present application mainly uses degradable biomass materials as raw materials, and does not form secondary pollution to the environment during use. Meanwhile, the present application can improve the water retention of the composite grass planting blanket through layer structure design, which is beneficial to the growth of vegetation. The composite grass planting blanket provided by the present application has good erosion resistance, and prolongs the service life of the composite grass planting blanket. When the composite grass planting blanket is used to restore the lake and reservoir drawdown belt steep slope area, the lake and reservoir drawdown belt steep slope area is divided into a frequently submerged area, a wind and wave erosion area and a lightly submerged area, and different types of plants are planted in different areas, so as to ensure the survival rate of the plants, reduce water and soil loss, and effectively realize ecological restoration.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ecological restoration, and particularly relates to a composite grass planting system, a preparation method and application, and a damaged ecological system restoration method for steep slope areas of lake and reservoir drawdown zones. BACKGROUND

[0002] The lake and reservoir drawdown zone is a region between the highest and lowest water level lines of the land alternately submerged and exposed due to seasonal water level fluctuation of rivers, lakes and reservoirs. The drawdown zone is alternately controlled and influenced by water and land ecosystems, and is a special wetland ecosystem, which is a typical ecological transition zone. The vegetation in the drawdown zone has multiple important ecological functions such as filtering sediment and nutrients, soil and water conservation, stabilizing the riverbank system, and protecting the water quality of the river, and has certain landscape aesthetic function and social and economic benefits. However, when planting vegetation in the lake and reservoir drawdown zone, the seeds are prone to be washed away by water flow. Due to the particularity of the lake and reservoir drawdown zone, the vegetation may rot during the flooding period or die of water shortage during the drought period. Moreover, the steep slope terrain superimposes strong water erosion, which aggravates soil erosion. At present, the hard revetment reinforcement method is mainly used to reduce soil erosion. However, the conventional structure has poor ecological compatibility, and the synthetic fiber or plastic base material used in the construction process has a long degradation period and is prone to produce microplastic pollution, thereby affecting the ecological environment. How to realize the ecological restoration of the lake and reservoir drawdown zone and improve the ecological environment is a technical problem to be solved at present. SUMMARY

[0003] Therefore, the present application provides a composite grass planting system, a preparation method and application, and a damaged ecological system restoration method for steep slope areas of lake and reservoir drawdown zones. The composite grass carpet provided by the present application has good erosion resistance and is degradable, and will not cause additional pollution to the environment. The composite grass carpet provided by the present application is used to plant different types of plants in different submerged areas to realize ecological restoration, which can effectively improve the ecological environment of the lake and reservoir drawdown zone.

[0004] In order to solve the above technical problems, the present application provides a composite grass carpet, which comprises a composite fiber carpet and a biomimetic fiber aquatic plant inserted into the composite fiber carpet.

[0005] The composite fiber carpet comprises a support layer, a water retention layer and a protection layer which are stacked in sequence. The support layer comprises a coconut shell fiber woven net and a polylactic acid melt-blown non-woven fabric coated on the surface of the coconut shell fiber woven net. The water retention layer comprises a base body and a functional material attached to the base body. The base body is a coconut shell fiber felt, and the functional material comprises starch-based superabsorbent resin, attapulgite clay powder and grass seeds. The protection layer is a polylactic acid monofilament woven net.

[0006] The bionic fiber water grass comprises a bionic spiral anchor rod and water grass blades fixed on the bionic spiral anchor rod; the water grass blades are a composite fiber woven product, raw materials for preparing the composite fiber woven product include warp and weft, the warp includes polyester fibers or polypropylene fibers; the weft includes main weft and functional weft, the main weft includes polyester fibers or polypropylene fibers; the functional weft includes high-density polyethylene fiber ropes loaded with activated carbon;

[0007] Raw materials for preparing the bionic spiral anchor rod include high-density polyethylene.

[0008] Preferably, the thickness of the composite grass planting blanket is 12.3-17.5 mm, and the dry-state thickness of the water-retaining layer is 8-12 mm;

[0009] The grammage of the coconut fiber felt is 95-102 g / m 2 ;

[0010] The average particle size of the starch-based superabsorbent resin is 0.5-1 mm, the mass percentage of the starch-based superabsorbent resin in the water-retaining layer is 18-22%, the average particle size of the attapulgite clay powder is 5-15 μm, and the mass percentage of the attapulgite clay powder in the water-retaining layer is 8-12%.

[0011] Preferably, the thickness of the support layer is 3.5-4 mm, the tensile strength of the coconut fiber woven net is ≥8 kN / m, and the grammage of the polylactic acid melt-blown non-woven fabric is 28-32 g / m 2 ;

[0012] The thickness of the protective layer is 0.8-1.2 mm, the pore size of the polylactic acid monofilament woven net is 1.8 cm×1.8 cm-2.2 cm×2.2 cm, and the grammage is ≥350 g / m 2 .

[0013] Preferably, the water grass blades contain a pore structure, and the pore size of the pore structure is 50-200 μm;

[0014] The compressed-state width of the water grass blades is 2.7-3.3 cm, and the relaxed-state width is 4.5-5.5 cm; the length of the water grass blades is 95-105 cm; and the specific surface area of the water grass blades is ≥1200 m 2 / m 3 ;

[0015] The ratio of the number of main weft to functional weft in the weft is 2-2.3:1; the mass percentage of activated carbon in the functional weft is 40-50%; and the activated carbon includes coconut activated carbon;

[0016] The preparation method of the functional weft comprises the following steps: mixing high-density polyethylene and activated carbon, then performing double-screw extrusion and pelletizing to obtain a composite master batch; performing wire drawing on the composite master batch, then twisting and plying to obtain the functional weft.

[0017] Preferably, the bionic spiral anchor rod has a hollow structure, and a mixture of cement and sand is filled in the lumen of the hollow structure.

[0018] The pitch of the bionic spiral anchor rod is 3.8-4.2 cm; the bionic spiral anchor rod is provided with anti-skid convex points on the surface, and the height of the anti-skid convex points is 0.8-1.2 mm.

[0019] The bionic spiral anchor rod comprises a soil-entering section and a connecting section, the length of the soil-entering section is 28-32 cm, and the length of the connecting section is 8-12 cm; the diameter of the bionic spiral anchor rod is 3.8-4.2 cm.

[0020] The application further provides a preparation method of the composite grass planting blanket, comprising the following steps:

[0021] The support layer is obtained by laying the coconut fiber woven net, covering the polylactic acid melt-blown non-woven fabric, and then performing hot pressing molding.

[0022] The water-retaining layer is obtained by dispersing the functional material in the coconut fiber felt and then performing first fixing.

[0023] The composite fiber blanket is obtained by stacking the support layer, the water-retaining layer and the polylactic acid monofilament woven net from bottom to top and then performing second fixing.

[0024] The warp and weft are woven to obtain the water and grass leaves; the warp comprises polyester fibers or polypropylene fibers; the weft comprises main weft and functional weft, the main weft comprises polyester fibers or polypropylene fibers; the functional weft comprises high-density polyethylene fiber ropes loaded with activated carbon; one functional weft is arranged every 2 main wefts.

[0025] The bionic spiral anchor rod is obtained by injection molding of high-density polyethylene.

[0026] The composite grass planting blanket is obtained by fixing the water and grass leaves to the bionic spiral anchor rod and then inserting the bionic spiral anchor rod into the composite fiber blanket.

[0027] Preferably, the temperature of the hot pressing molding is 160-170 DEG C, the pressure is 0.28-0.32 MPa, and the holding time is 28-32 s.

[0028] The first fixing mode comprises first needling, the density of the first needling is 14-16 needles / cm 2 , and the depth of the first needling is 9-11 mm.

[0029] The second fixing mode comprises: laminating the support layer and the water-retaining layer and then hot pressing, and laminating the hot-pressed product and the protective layer and then second needle punching; the density of the second needle punching is 15-20 needles / cm 2 ;

[0030] The weaving further comprises: hot setting the woven product, the temperature of the hot setting is 120-130 DEG C, and the holding time of the hot setting is 3-5 min;

[0031] The injection molding conditions comprise: the barrel temperature is 280-300 DEG C, the injection pressure is 60-80 MPa, the holding pressure is 40-50 MPa, the holding time is 25-35 s, and the mold temperature is 40-60 DEG C.

[0032] The application also provides application of the composite grass planting carpet prepared by the preparation method to restoration of damaged ecological systems in steep slope areas of lake drawdown zones.

[0033] The application also provides a method for restoring damaged ecological systems in steep slope areas of lake drawdown zones, comprising the following steps:

[0034] The steep slope area of the lake drawdown zone is divided into a perennially submerged area, a wind and wave erosion area and a lightly submerged area, and the composite grass planting carpet is laid; the wind and wave erosion area is an area with an elevation of 0.5 m above and below the normal water level; the perennially submerged area is an area from the lower side of the wind and wave erosion area to a water depth of 2 m, and the perennially submerged area is below the water depth of 0.5 m all the year round; the lightly submerged area is an area from the wind and wave erosion area to the flood level;

[0035] The submerged plants and emergent plants are cut and planted on the composite grass planting carpet in the perennially submerged area and the lightly submerged area, respectively.

[0036] Preferably, the density of the biomimetic fiber water grass on the composite grass planting carpet in the perennially submerged area is 6-10 bundles / m 2 ; the diameter of the hole for cutting and planting the submerged plants is 180-220 mm, the number of the submerged plants in each hole is 4-6, the hole has a Chinese character shape structure, and the distance between adjacent holes is 0.4-0.6 m;

[0037] The density of the biomimetic fiber water grass on the composite grass planting carpet in the wind and wave erosion area is 16-36 bundles / m 2 ;

[0038] The density of the biomimetic fiber water grass on the composite grass planting carpet in the lightly submerged area is 4-6 bundles / m 2The diameter of the hole for inserting the emergent plant is 180-220 mm, the number of the emergent plant in each hole is 3-5, and the holes are in the shape of a Chinese character "。

[0039] The application provides a composite vegetation blanket, which comprises a composite fiber blanket and biomimetic fiber aquatic plants inserted into the composite fiber blanket. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The structure diagram of the composite vegetation blanket is provided.

[0041] Figure 2 The structure diagram of the composite fiber blanket is provided.

[0042] Figure 3 The structure diagram of the biomimetic fiber aquatic plant is provided.

[0043] Figure 4 The side view diagram of the damaged ecological system of the lake and reservoir drawdown belt steep slope area repaired by the composite vegetation blanket is provided.

[0044] Figure 5 The front view diagram of the damaged ecological system of the lake and reservoir drawdown belt steep slope area repaired by the composite vegetation blanket is provided. DETAILED DESCRIPTION

[0045] The application provides a composite grass planting blanket, which comprises a composite fiber blanket and a biomimetic fiber water plant transplanted in the composite fiber blanket.

[0046] In the application, the composite fiber blanket comprises a support layer, a water retention layer and a protection layer which are sequentially stacked; the support layer comprises a coconut shell fiber woven net and a polylactic acid melt-blown non-woven fabric coated on the surface of the coconut shell fiber woven net; the tensile strength of the coconut shell fiber woven net is greater than or equal to 8 kN / m, 8-15 kN / m, and can be specifically 8.5 kN / m, 9 kN / m or 10 kN / m; the grammage of the polylactic acid melt-blown non-woven fabric can be 28-32 g / m 2 , and can be specifically 30 g / m 2 . As a specific embodiment of the application, the total grammage of the support layer can be greater than or equal to 350 g / m 2 , and can also be 380-420 g / m 2 , 380 g / m 2 or 400 g / m 2 ; the thickness of the support layer can be 3.5-4 mm, and can be specifically 3.7 mm, 3.8 mm or 3.9 mm; in the use process of the composite grass planting blanket provided by the application, the support layer can increase the adhesion of the composite grass planting blanket to the ground by about 40%, and the initial anti-sediment loss rate is greater than 90%. In the application, the support layer of the composite grass planting blanket directly contacts the ground in the use process; the support layer has the anti-erosion property, can be well adhered to the ground and can enhance the anchoring effect.

[0047] In the application, the water retention layer comprises a base body and a functional material attached to the base body; the base body is a coconut shell fiber felt; the functional material comprises starch-based superabsorbent resin, attapulgite clay powder and grass seeds; the grammage of the coconut shell fiber felt can be 95-102 g / m 2 , and can be specifically 98 g / m 2 or 100 g / m 2; the average particle size of the starch-based superabsorbent resin (SAP) can be 0.5-1 mm, and can be specifically 0.8 mm; the mass percentage of the starch-based superabsorbent resin in the water-retaining layer can be 18-22%, and can be specifically 20%; the water retention rate of the starch-based superabsorbent resin can be 300% or more, and can also be 320-360%, and can be specifically 350%; the average particle size of the attapulgite clay powder can be 5-15 μm, and can be specifically 8 μm, 10 μm or 13 μm; the mass percentage of the attapulgite clay powder in the water-retaining layer can be 8-12%, and can be specifically 10%; the ion exchange capacity of the attapulgite clay powder can be 110-130 mmol / 100 g, and can be specifically 120 mmol / 100 g. As a specific embodiment of the present application, the grass seeds can be one or more of centipede grass seeds, tall fescue seeds, white clover seeds, reed seeds and cattail seeds, and can be specifically a mixed seed of centipede grass seeds, tall fescue seeds, white clover seeds, reed seeds and cattail seeds, centipede grass seeds, tall fescue seeds, white clover seeds, reed seeds or cattail seeds. In the present application, when the grass seeds are a mixed seed of centipede grass seeds, tall fescue seeds, white clover seeds, reed seeds and cattail seeds, the mass percentage of the centipede grass seeds, tall fescue seeds, white clover seeds, reed seeds and cattail seeds in the grass seeds can be 40%, 30%, 10%, 10% and 10%, respectively. As a specific embodiment of the present application, the content of the grass seeds in the water-retaining layer can be 28-32 g / m 2 , and can be specifically 30 g / m 2 . As a specific embodiment of the present application, the dry thickness of the water-retaining layer can be 8-12 mm, and can be specifically 10 mm. In the present application, the structure of the water-retaining layer can make the retention rate of the grass seeds >95%, maintain a water permeation rate of about 10 cm / h, and effectively prevent water accumulation; the water-retaining layer can protect the grass seeds from being washed away in large quantities, and can also provide water and nutrient components for the grass seeds and vegetation.

[0048] In the present application, the protective layer is a polylactic acid monofilament woven mesh; the pore size of the polylactic acid monofilament woven mesh can be 1.8 cm x 1.8 cm-2.2 cm x 2.2 cm, and can be specifically 2 cm x 2 cm; the grammage of the polylactic acid monofilament woven mesh can be ≥ 350 g / m 2 , and can also be 360-420 g / m 2 , and can be specifically 360 g / m 2 , 380 g / m 2 or 400 g / m 2As a specific embodiment of the present application, the thickness of the protective layer can be 0.8-1.2 mm, and can be specifically 1 mm. In the present application, the main role of the protective layer is to protect the water-retaining layer. The mechanical strength of the polylactic acid monofilament woven mesh directly withstands and disperses the scouring force of the water flow, thereby effectively reducing the erosion and scouring of the coconut coir felt and functional materials in the water-retaining layer by the water force, and ensuring the overall structural integrity of the composite grass planting blanket. At the same time, the pore structure in the protective layer can transmit light to promote seed germination and provide growth space for seed germination.

[0049] In the present application, the thickness of the composite grass planting blanket can be 12.3-17.5 mm, and can be specifically 13 mm, 14 mm, 14.8 mm, 15 mm or 16 mm.

[0050] In the present application, the bionic fiber water grass includes a bionic spiral anchor rod and water grass blades fixed on the bionic spiral anchor rod; the water grass blades are a composite fiber woven product, and the raw materials for preparing the composite fiber woven product include warp and weft, the warp includes polyester (PET) fiber or polypropylene (PP) fiber; the weft includes main weft and functional weft, the main weft includes polyester (PET) fiber or polypropylene (PP) fiber; the functional weft includes a high-density polyethylene (HDPE) fiber rope loaded with activated carbon; the ratio of the number of main weft to functional weft in the weft can be 2-2.3:1; the mass percentage content of activated carbon in the functional weft can be 40-50%, and can also be 13-45%; the activated carbon can include coconut shell activated carbon; the particle size of the activated carbon can be 180-200 mesh. As a specific embodiment of the present application, the preparation method of the functional weft can include the following steps: mixing high-density polyethylene and activated carbon, then performing double-screw extrusion and pelletizing to obtain a composite master batch; after drawing the composite master batch, twisting and plying to obtain the functional weft; the temperature of the double-screw extrusion can be 175-195℃, and can also be 180-190℃; the rotation speed of the double-screw extrusion can be 120-150 rpm, and can also be 130-140 rpm; the average particle size of the composite master batch is 2.5-3.5 mm, and can be specifically 3 mm; the temperature of the drawing can be 185-205℃, and can also be 190-200℃; the diameter of the product after drawing can be 1.7-1.9 nm, and can be specifically 1.8 nm; the twisting and plying can be twisting and plying 6 single filaments obtained by drawing at a twist of <80 twists / meter, and the breaking strength of the functional weft is ≥120 N, and can be 130-140 N. In the present application, polyester fiber and polypropylene fiber have excellent ultraviolet aging resistance and high strength, which can ensure the structural durability of the water grass blades.

[0051] As a specific embodiment of the present application, the water grass leaf contains a pore structure, the porosity of the water grass leaf can be 83-87%, and can be specifically 85%; the pore size of the pore structure can be 50-200 μm, and can be specifically 80 μm, 100 μm, 130 μm, 150 μm or 180 μm; the compressed state width of the water grass leaf can be 2.7-3.3 cm, and can be specifically 3 cm; the relaxed state width of the water grass leaf can be 4.5-5.5 cm, and can be specifically 5 cm; the length of the water grass leaf can be 95-105 cm, and can be specifically 100 cm; the specific surface area of the water grass leaf can be ≥1200 m 2 / m 3 , and can be specifically 1200-1400 m 2 / m 3 , and can be specifically 1250 m 2 / m 3 or 1300 m 2 / m 3 ; the grammage of the water grass leaf can be 200-240 g / m 2 , and can be specifically 210 g / m 2 , 220 g / m 2 or 230 g / m 2 .

[0052] In the present application, the raw material for preparing the bionic spiral anchor rod includes high-density polyethylene. As a specific embodiment of the present application, the bionic spiral anchor rod has a hollow structure, and the lumen of the hollow structure can be filled with a mixture of cement and sand; the mass ratio of cement to sand in the mixture of cement and sand can be 0.8-1.2:1, and can be specifically 1:1; the present application can improve the overturning stability of the bionic spiral anchor rod by filling the lumen of the hollow structure with the mixture of cement and sand. As a specific embodiment of the present application, the pitch of the bionic spiral anchor rod can be 3.8-4.2 cm, and can be specifically 4 cm; the bionic spiral anchor rod is provided with anti-skid convex points on the surface, the height of the anti-skid convex points can be 0.8-1.2 mm, and can be specifically 1 mm; the bionic spiral anchor rod includes a soil-penetrating section and a connecting section, the length of the soil-penetrating section can be 28-32 cm, and can be specifically 30 cm; the length of the connecting section can be 8-12 cm, and can be specifically 10 cm; the diameter of the bionic spiral anchor rod can be 3.8-4.2 cm, and can be specifically 4 cm. In the present application, the pullout force of the bionic spiral anchor rod can be ≥1000 N, and can be specifically 1160-1390 N; the rotary insertion torque of the bionic spiral anchor rod can be ≤18 N·m, and can be specifically ≤10 N·m.

[0053] As a specific embodiment of the present application, the bionic spiral anchor rod can be connected and fixed with the water grass blade through a U-shaped clamping groove.

[0054] Figure 1 A structural schematic diagram of the composite vegetation mat provided by the present application is shown in the figure. Figure 2 A structural schematic diagram of the composite fiber mat is shown in the figure. Figure 3 A structural schematic diagram of the bionic fiber water grass is shown in the figure. The composite vegetation mat provided by the present application has a three-layer structure of a support layer, a water retention layer and a protection layer, and presents an orderly degradation gradient according to the growth cycle of vegetation: (1) the water retention layer degrades first (6-8 months): the coconut shell fiber and the starch-based SAP degrade rapidly to provide water and space for the growth of seedlings; (2) the protection layer degrades in the middle period (1-2 years): the PLA monofilament woven mesh degrades after the initial formation of the root system of the vegetation, completing the initial mission of anti-erosion and light transmission; (3) the support layer degrades for a long time (2-3 years): the coconut shell fiber woven mesh and the PLA melt-blown cloth composite degrade the slowest, ensuring the slope function to be effective continuously before the vegetation community is completely stable. The gradient degradation of the present application matches the cycle of vegetation "germination-growth-stability", and all degradation products are organic fertilizers, realizing zero pollution throughout the process.

[0055] The present application also provides a preparation method of the composite vegetation mat according to the above technical solution, which comprises the following steps:

[0056] The coconut shell fiber woven mesh is laid flat and then covered with the PLA melt-blown non-woven fabric for hot pressing to form a support layer.

[0057] The functional material is dispersed in the coconut shell fiber felt for first fixation to obtain a water retention layer.

[0058] The support layer, the water retention layer and the PLA monofilament woven mesh are stacked from bottom to top for second fixation to obtain the composite fiber mat.

[0059] The warp and weft are woven to obtain a water grass blade; the warp comprises polyester fiber or polypropylene fiber; the weft comprises main weft and functional weft, the main weft comprises polyester fiber or polypropylene fiber; the functional weft comprises a high-density polyethylene fiber rope loaded with activated carbon; one functional weft is arranged every 2 main wefts;

[0060] The high-density polyethylene is injection molded to obtain a bionic spiral anchor rod.

[0061] The water grass blade is fixed to the bionic spiral anchor rod and then inserted into the composite fiber mat to obtain the composite vegetation mat.

[0062] The present application lays the coconut shell fiber woven net, covers the polylactic acid melt-blown non-woven fabric, and then performs hot pressing to obtain a support layer. As a specific embodiment of the present application, the temperature of the hot pressing can be 160-170 DEG C, and can be specifically 165 DEG C; the pressure of the hot pressing can be 0.28-0.32 MPa, and can be specifically 0.3 MPa; the holding time of the hot pressing can be 28-32 s, and can be specifically 30 s. As a specific embodiment of the present application, the hot pressing can further include cooling the product after the hot pressing to obtain the support layer; the temperature after the cooling can be 20-40 DEG C, and can be specifically 25-30 DEG C; the present application does not have special requirements for the cooling method, as long as the required temperature can be reached.

[0063] In the present application, the coconut shell fiber woven net serves as a main bearing structure to provide main mechanical anchoring force; the polylactic acid (PLA) melt-blown non-woven fabric is partially embedded in the mesh of the coconut shell fiber woven net under hot pressing, effectively fills the gaps, prevents the loss of the underlying soil, and significantly enhances the adhesion to the slope surface.

[0064] The present application disperses the functional material in the coconut shell fiber felt to perform first fixing to obtain a water-retaining layer. As a specific embodiment of the present application, the first fixing method can include first needling, the density of the first needling can be 14-16 needles / cm 2 , and can be specifically 15 needles / cm 2 ; the depth of the first needling can be 9-11 mm, and can be specifically 10 mm. The present application can fix the functional material in the coconut shell fiber felt matrix by needling.

[0065] After obtaining the support layer and the water-retaining layer, the present application stacks the support layer, the water-retaining layer, and the polylactic acid monofilament woven net from bottom to top to perform second fixing to obtain the composite fiber blanket. As a specific embodiment of the present application, the second fixing method can include hot pressing the stacked support layer and water-retaining layer, and second needling the product after the hot pressing and the protective layer; the temperature of the hot pressing can be 160-175 DEG C, and can be specifically 165 DEG C or 170 DEG C; the pressure of the hot pressing can be 0.4-0.6 MPa, and can be specifically 0.4 MPa or 0.5 MPa; the holding time of the hot pressing can be 40-60 s, and can be specifically 45 s or 50 s; the density of the second needling can be 15-20 needles / cm 2 , and can be specifically 16-18 needles / cm 2The second needle depth is allowed to penetrate the protective layer. The application makes the polylactic acid on the surface of the support layer soften and melt to adhere to the coconut shell fiber in the water-retaining layer by hot pressing to form a preliminary composite; the preliminary composite of the "support-function" double-layer structure is combined with the protective layer, and the needle punching process is used for final fixing, and the needle depth is preferably allowed to penetrate the protective layer and hook the water-retaining layer in the middle; part of the coconut shell fiber in the water-retaining layer is carried into the upper and lower layers during the needle process to form a mechanical interlocking structure, and the mechanical stability of the composite fiber blanket is improved.

[0066] The invention weaves warp and weft to obtain water grass leaves; the warp includes polyester fiber or polypropylene fiber; the weft includes main weft and functional weft, the main weft includes polyester fiber or polypropylene fiber; the functional weft includes high-density polyethylene fiber rope loaded with activated carbon; every interval of 2 main wefts is provided with a functional weft. As a specific embodiment of the invention, the weaving device can be a 32-spindle high-speed tubular weaving machine, the spindle speed of the high-speed tubular weaving machine can be 350-400 rpm, which can be specifically 360 rpm, 370 rpm, 380 rpm or 390 rpm; the traction roller speed of the high-speed tubular weaving machine can be 2.0-2.5 m / min, which can be specifically 2.1 m / min, 2.2 m / min, 2.3 m / min or 2.4 m / min.

[0067] As a specific embodiment of the invention, the woven product can further include heat setting, the heat setting temperature can be 120-130 DEG C, which can be specifically 125 DEG C; the heat setting holding time can be 3-5 min, which can be specifically 4 min.

[0068] The water grass leaves provided by the invention are in a relaxed state in a natural state, and when subjected to water flow impact, the leaves can be flexibly deformed in the direction of the water flow to form a compressed state, and this "flow-dependent property" can effectively reduce the water flow energy; the invention provides a special weaving process, and the water grass leaves have a large volume-specific surface area, providing a large attachment space for microbial biofilm.

[0069] The invention injects and molds high-density polyethylene to obtain a biomimetic spiral anchor rod. As a specific embodiment of the invention, the injection molding conditions can include: barrel temperature 280-300 DEG C, injection pressure 60-80 MPa, holding pressure 40-50 MPa, holding time 25-35 s, mold temperature 40-60 DEG C; it can also be: barrel temperature 290-295 DEG C, injection pressure 65-75 MPa, holding pressure 43-45 MPa, holding time 28-30 s, mold temperature 45-50 DEG C.

[0070] As a specific embodiment of the present application, the post-injection molding can further include: injecting a mixture of cement and sand into the hollow structure of the injection molded product, and then sealing the injection hole with a prefabricated product plug made of high-density polyethylene material in a hot melt manner to ensure that the filler does not leak out.

[0071] After obtaining the composite fiber blanket, the aquatic plant leaf and the biomimetic spiral anchor rod, the aquatic plant leaf is fixed to the biomimetic spiral anchor rod and then is cuttage on the composite fiber blanket to obtain the composite vegetation blanket.

[0072] The present application also provides the application of the composite vegetation blanket prepared by the preparation method in the repair of damaged ecological system in the steep slope area of lake drawdown zone.

[0073] The present application also provides a method for repairing damaged ecological system in the steep slope area of lake drawdown zone, which comprises the following steps:

[0074] The composite vegetation blanket is laid on the steep slope area of lake drawdown zone after the area is divided into a perennially submerged area, a wind and wave erosion area and a lightly submerged area; the wind and wave erosion area is an area with an elevation of 0.5 m above and below the normal water level; the perennially submerged area is an area from the lower side of the wind and wave erosion area to a water depth of 2 m, and the perennially submerged area is always below a water depth of 0.5 m; the lightly submerged area is an area from the wind and wave erosion area to the flood level line;

[0075] Submerged plants and emergent plants are cuttage on the composite vegetation blanket in the perennially submerged area and the lightly submerged area, respectively.

[0076] The present application also includes a preliminary preparation before the repair, which can comprise the following steps: generating a slope digital elevation model (DEM) after surveying the terrain; dividing the steep slope area of lake drawdown zone into a perennially submerged area, a wind and wave erosion area and a lightly submerged area according to the slope digital elevation model and historical water level data.

[0077] The application further comprises pretreating the composite fiber blanket and the biomimetic fiber water grass before repairing; the method for pretreating the composite fiber blanket can comprise the following steps: spraying a humic acid solution to the water-retaining layer of the composite fiber blanket; the mass concentration of the humic acid solution can be 0.08-0.12%, and can be specifically 0.1%; the spraying amount can be 0.48-0.52 L / m 2 , and can be specifically 0.5 L / m 2 . The application activates the starch-based superabsorbent resin (SAP) in the water-retaining layer by spraying the humic acid solution

[0078] The method for pretreating the biomimetic fiber water grass can comprise the following steps: immersing the biomimetic fiber water grass in a nitrifying bacteria liquid for 30 min for microbial inoculation; the bacterial concentration in the nitrifying bacteria liquid is greater than or equal to 1×10 6 CFU / mL.

[0079] The laying method of the composite vegetation blanket is not particularly limited, and the laying can be performed according to the conventional method in the art.

[0080] The composite vegetation blanket in the frequently-submerged area is mainly protected and secondarily repaired. As a specific embodiment of the application, the density of the biomimetic fiber water grass on the composite vegetation blanket in the frequently-submerged area can be 6-10 bundles / m 2 , and can be specifically 7 bundles / m 2 , 8 bundles / m 2 , or 9 bundles / m 2 ; the diameter of the hole for cutting the submerged plant can be 180-220 mm, and can be specifically 190 mm, 200 mm, or 210 mm; the number of the submerged plant in each hole can be 4-6, and can be specifically 5; the hole has a character-shaped structure, and the distance between adjacent holes can be 0.4-0.6 m, and can be specifically 0.5 m.

[0081] In the application, the wind and wave erosion area is seriously eroded by the frequent water level and wind waves, and it is difficult for plants to survive. The composite vegetation blanket is fully provided in the area to protect the revetment. As a specific embodiment of the application, the density of the biomimetic fiber water grass on the composite vegetation blanket in the wind and wave erosion area can be 16-36 bundles / m 2 , and can be specifically 18 bundles / m 2 , 20 bundles / m 2 , 25 bundles / m 2 , 30 bundles / m 2 , or 33 bundles / m 2 .

[0082] In the present application, the slightly submerged area is located in the wind wave erosion area to the flood level line area, which is mostly on the shore and submerged at high water level, and is affected by hydraulic erosion and plant submergence, so the area is mainly protected and supplemented by repair. As a specific embodiment of the present application, the density of the bionic fiber water grass on the composite grass carpet in the slightly submerged area can be 4-6 bundles / m 2 , specifically 5 bundles / m 2 ; the diameter of the hole for cutting the emergent plant can be 180-220 mm, specifically 190 mm, 200 mm or 210 mm; the number of emergent plants in each hole can be 3-5, specifically 3 or 5; the hole has a character shape structure, and the distance between adjacent holes can be 0.4-0.6 m, specifically 0.5 m.

[0083] Figure 4 is a side view schematic diagram of the present application for repairing the damaged ecosystem in the steep slope area of the lake and reservoir drawdown zone using a composite grass carpet; Figure 5 is a front view schematic diagram of the present application for repairing the damaged ecosystem in the steep slope area of the lake and reservoir drawdown zone using a composite grass carpet.

[0084] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0085] Example 1

[0086] The woven coconut fiber net with a tensile strength of 9 kN / m is laid flat and covered with a poly-lactic acid melt-blown non-woven fabric with a grammage of 30 g / m 2 , and then heated and pressurized at a temperature of 165℃ and a pressure of 0.3 MPa for 30 s, and then cooled to 30℃, to obtain a support layer with a thickness of 3.8 mm and a total grammage of 380 g / m 2 .

[0087] The functional material is uniformly dispersed in a coconut fiber felt with a grammage of 100 g / m 2 , and then needled (the density of needling is 15 needles / cm 2, the depth of needling is 10 mm), to obtain a water storage layer with a dry thickness of 10 mm; the functional material comprises starch-based superabsorbent resin with an average particle size of 0.8 mm and a water retention rate of 350%, attapulgite clay powder with an average particle size of 10 μm and an ion exchange capacity of 120 mmol / 100 g, and mixed grass seeds, wherein the mass percentage of the starch-based superabsorbent resin in the water storage layer is 20%, the mass percentage of the attapulgite clay powder in the water storage layer is 10%, and the mixed grass seeds comprise grass seeds with the following mass percentages: 40% of centipede grass seeds, 30% of tall fescue seeds, 10% of white clover seeds, 10% of ryegrass seeds, and 10% of cattail seeds, and the content of the grass seeds in the water storage layer is 30 g / m 2 ;

[0088] After the support layer and the water storage layer are stacked, they are kept at a temperature of 165 ℃ and a pressure of 0.5 MPa for 50 s, and then are stacked with a polylactic acid monofilament knitted mesh layer with a grammage of 380 g / m 2 , a thickness of 1 mm, and a pore size of 2 cm x 2 cm, the needling density is 17 needles / cm 2 , to obtain a composite fiber blanket with a thickness of 14.8 mm; wherein the water storage layer is in direct contact with the polylactic acid monofilament knitted mesh, and the depth of needling is to penetrate the protective layer;

[0089] The high-density polyethylene and the activated carbon are mixed at a mass ratio of 55:45, and then are subjected to double-screw extrusion (temperature: 180 ℃, rotation speed: 140 rpm) and pelletization, to obtain a composite master batch with an average particle size of 3 mm; the composite master batch is drawn at 200 ℃, to obtain monofilaments with a diameter of 1.8 nm, 6 monofilaments are twisted and plied at a twist of 70 twists / m, to obtain functional weft with a breaking strength of 140 N; the weft is woven by using a 32-spindle high-speed tubular weaving machine, polyester fibers are used as warp, and 16 wefts are evenly distributed; the functional weft and the polypropylene fibers are set as weft in a cycle mode of 2 polypropylene wefts and 1 functional weft; the spindle rotation speed of the weaving machine is 400 rpm, and the traction roller speed is 2.5 m / min; the product obtained by weaving is placed in a hot air oven for heat setting at 125 ℃ for 4 min, to obtain a water grass leaf with a porosity of 85%, an average pore size of the pore structure of 100 μm, a compressed state width of 3 cm, an expanded state width of 5 cm, a length of 100 cm, a specific surface area of 1250 m 2 / m 3 , and a grammage of 220 g / m 2 ;

[0090] The high-density polyethylene is injection molded to obtain a bionic spiral anchor rod with a hollow structure, a pitch of 4 cm, an anti-skid protrusion height of 1 mm, an earth-penetrating section length of 30 cm, and a connecting section length of 10 cm. The injection molding conditions include: a barrel temperature of 280 ℃, an injection pressure of 70 MPa, a holding pressure of 45 MPa, a holding time of 30 s, and a mold temperature of 50 ℃. A mixture of cement and sand with a mass ratio of 1:1 is injected into the hollow structure of the injection-molded product, and then a prefabricated product plug made of high-density polyethylene is used to seal the injection hole in a hot melt manner.

[0091] The end of the water grass blade is embedded into the U-shaped clamping groove of the connecting anchor rod, and a stainless steel bolt assembly is used for fastening, with the fastening torque controlled at about 4.5 N·m. The connecting section of the bionic spiral anchor rod is passed through the hole reserved in the composite fiber carpet, and is locked with a coconut fiber rope to make the tensile strength 2 kN, thereby obtaining a composite grass planting carpet.

[0092] Test Example 1

[0093] The composite grass planting carpet prepared in Example 1 is used to repair the damaged ecosystem in the steep slope area of the lake and reservoir drawdown zone, and the repair includes the following steps:

[0094] The composite fiber carpet prepared in Example 1 is cut into a composite fiber carpet with a size of 2 m x 10 m.

[0095] After the terrain is surveyed by a drone, a slope digital elevation model (DEM) with a precision of 1:500 is generated. According to the slope digital elevation model and historical water level data, the steep slope area of the lake and reservoir drawdown zone is divided into a frequently submerged area, a wind wave erosion area, and a lightly submerged area. The wind wave erosion area is a region with a height of 0.5 m above and below the normal water level. The frequently submerged area is a region from the lower side of the wind wave erosion area to a water depth of 2 m, and the frequently submerged area is always below a water depth of 0.5 m. The lightly submerged area is from the wind wave erosion area to the flood level line.

[0096] The composite fiber carpet is pretreated according to the following steps: spraying a humic acid solution with a mass concentration of 0.1% onto the water-retaining layer of the composite fiber carpet, and the spraying amount is 0.5 L / m 2 The bionic fiber water grass is pretreated according to the following steps: immersing the bionic fiber water grass in a nitrifying bacteria solution with a bacterial concentration of 1 x 10 6 CFU / mL for 30 min for microbial inoculation, and the microbial load of the water grass blade is 8 x 10 6 CFU / g;

[0097] The pretreated composite grass planting carpet is laid in the frequently submerged area, the wind wave erosion area, and the lightly submerged area. The bionic fiber water grass and submerged plants are inserted on the composite grass planting carpet in the frequently submerged area. The density of the bionic fiber water grass is 7 bundles / m 2, the hole diameter of the hole product letter-shaped structure is 200 mm, the interval of adjacent holes is 0.5 m, and the number of the submerged plants in each hole is 5; the bionic fiber water grass is grafted on the composite vegetation blanket in the wind wave erosion area, and the density of the bionic fiber water grass is 25 bundles / m 2 ; the bionic fiber water grass and the emergent plant are grafted in the light submergence area, the density of the bionic fiber water grass on the composite vegetation blanket in the light submergence area is 5 bundles / m 2 ; the hole product letter-shaped structure of the emergent plant is grafted, the hole diameter is 200 mm, the interval of adjacent holes is 0.5 m, and the number of the emergent plants in each hole is 5.

[0098] The performance of the composite vegetation blanket is detected according to the following method:

[0099] Seed resistance to erosion test: the composite fiber blanket prepared in Example 1 is placed in an erosion tank with a slope of 30°, and after being eroded at a flow rate of 1.5 m / s for 48 h, the seed retention rate is determined to be >95%.

[0100] Sediment loss prevention efficiency: 1) Test method overview

[0101] A standard slope tank is used to simulate the steep slope conditions of the lake and reservoir drawdown zone (slope 30°), and the composite vegetation blanket sample (2.0 m x 0.5 m) is laid on the bed of standard test soil (bulk density 1.4±0.05 g / cm 3 ). A simulated rainfall with an intensity of 50 mm / h is applied for 60 min, and all the surface runoff is collected. The total sediment loss mass is determined by the filtration and drying method, and compared with the control group of bare slope, and the sediment loss prevention efficiency is calculated.

[0102] 2) Core test parameters

[0103] Test slope: slope 30°, soil thickness 15 cm;

[0104] Rainfall intensity: 50 mm / h

[0105] Sample size: 2.0 m x 0.5 m

[0106] Test duration: 60 minutes

[0107] Sediment determination method: filtration and drying method (105±5°C to constant weight)

[0108] 3) Efficiency calculation formula

[0109] The sediment loss prevention efficiency (η) is calculated according to the following formula:

[0110] ;

[0111] Wherein: : bare slope (control group) total sediment loss mass (g), : laid grass blanket slope (experimental group) total sediment loss mass (g).

[0112] 4) Experimental conclusion

[0113] The average initial anti-sediment loss efficiency of the composite grass blanket under the above conditions is 92%, and the single test result is higher than 90%.

[0114] The composite grass blanket provided by the present application has the following advantages in repairing damaged ecosystems in steep slope areas of lake and reservoir drawdown zones:

[0115] 1. Improved ecological restoration efficiency

[0116] According to the method of the national standard "GB / T 12496", the adsorption capacity of the bionic water grass to NH4 + is ≥95mg / g, which greatly improves the self-purification capacity of the water body.

[0117] 2. Engineering performance breakthrough

[0118] To verify the key engineering performance of the composite grass blanket system of the present application, the following standardized test methods are used:

[0119] 1) Anchor rod pullout resistance test method

[0120] Method summary: The bionic spiral anchor rod is rotated into the saturated standard test soil to the designed depth (300mm into the soil), and a material testing machine is used to vertically pull at a rate of 5mm / min, and the peak pull force before failure is recorded.

[0121] Core parameters: saturated clay soil; constant pull rate 5mm / min; sample size 5.

[0122] Experimental conclusion: The average pullout resistance of the anchor rod under this condition is 1285N, the maximum pullout resistance is 1390N, and the minimum pullout resistance is 1160N, which meets and exceeds the design requirement of ≥1000N.

[0123] 2) Water flow impact resistance performance test method

[0124] Method summary: The bionic fiber water grass installed on the simulated bed is placed in a circulating water tank, and the flow rate is increased by 0.1m / s from 0.5m / s, each flow rate is maintained for 10min, and the structure state is observed.

[0125] Core parameters and criteria: flow rate step 0.1m / s; critical failure criterion is blade tearing, anchor rod pulling up or permanent damage to the main structure.

[0126] Experimental conclusion: all test samples did not appear structural damage under the impact of flow rate ≤1.8 m / s for 1 h, which proved that they could effectively resist the impact of normal water flow at this flow rate level.

[0127] 3) Wave height attenuation rate detection method

[0128] Method summary: in the wave tank, the biomimetic water grass was arranged at a density of 36 bundles / m 2 , the wave height instrument was arranged before and after the grass belt, the regular wave was generated, and the incident wave height (H1) and the transmitted wave height (H2) were measured synchronously.

[0129] Core parameters and calculation: water grass density 36 bundles / m 2 ; wave height attenuation rate η = [1-(H2 / H1] × 100%.

[0130] Experimental conclusion: under the test conditions of wave height 12 cm and period 1.5 s, the average wave height attenuation rate was 44.2% (n=5), and all single results were >42%, which proved that it had significant wave attenuation efficiency at the designed density.

[0131] 4) Water grass cutting torque detection method

[0132] Method summary: the operator uses a digital torque wrench to rotate the anchor rod into the saturated soil layer at a uniform speed to the designed depth, and records the maximum torque value in the process.

[0133] Core parameters: sample size n=10; performed in homogeneous saturated sand.

[0134] Experimental conclusion: the maximum rotational insertion torque of multiple tests is ≤10 N·m, indicating that the anchor rod can be easily installed by hand without relying on heavy machinery, and the construction convenience is high; at the same time, the prefabricated composite fiber blanket supports unmanned aerial vehicle throwing, and the laying efficiency is improved by 3 times.

[0135] 3. Environmental and economic advantages

[0136] Zero pollution throughout the cycle: 100% degradation within 2-3 years of material;

[0137] Cost reduction: activated carbon-based water grass cost ￥6.5 / bundle (traditional plastic water grass ￥12 / bundle); maintenance cost is reduced by 90% (no need to clean up degradation debris).

[0138] Although the above embodiments have made a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. A composite grass-planting mat, characterized in that, Includes a composite fiber blanket and biomimetic fiber aquatic plants inserted into the composite fiber blanket; The composite fiber blanket comprises a support layer, a water-retaining layer, and a protective layer stacked sequentially; the support layer comprises a coconut shell fiber woven mesh and a polylactic acid meltblown nonwoven fabric covering the surface of the coconut shell fiber woven mesh; the thickness of the support layer is 3.5~4mm, the tensile strength of the coconut shell fiber woven mesh is ≥8kN / m, and the basis weight of the polylactic acid meltblown nonwoven fabric is 28~32g / m². 2 ; The water-retaining layer comprises a matrix and functional materials attached to the matrix. The matrix is ​​coconut shell fiber felt, and the functional materials include starch-based superabsorbent resin, attapulgite clay powder, and grass seeds. The dry thickness of the water-retaining layer is 8-12 mm; the basis weight of the coconut shell fiber felt is 95-102 g / m³. 2 The starch-based superabsorbent polymer has an average particle size of 0.5-1 mm and accounts for 18-22% of the mass of the water-retaining layer. The attapulgite clay powder has an average particle size of 5-15 μm and accounts for 8-12% of the mass of the water-retaining layer. The protective layer is a polylactic acid monofilament woven mesh; the thickness of the protective layer is 0.8~1.2mm, the mesh size of the polylactic acid monofilament woven mesh is 1.8cm×1.8cm~2.2cm×2.2cm, and the basis weight is ≥350g / m². 2 ; The biomimetic fiber aquatic plant includes a biomimetic spiral anchor and aquatic plant leaves fixed to the biomimetic spiral anchor; the aquatic plant leaves are composite fiber woven products, and the raw materials for preparing the composite fiber woven products include warp and weft yarns, wherein the warp yarns include polyester fiber or polypropylene fiber; the weft yarns include main weft yarns and functional weft yarns, wherein the main weft yarns include polyester fiber or polypropylene fiber; the functional weft yarns include high-density polyethylene fiber ropes loaded with activated carbon; the ratio of the number of main weft yarns to functional weft yarns in the weft yarns is 2~2.3:1; the mass percentage of activated carbon in the functional weft yarns is 40~50%; the activated carbon includes coconut shell activated carbon. The raw material for preparing the biomimetic spiral anchor bolt includes high-density polyethylene.

2. The composite grass mat according to claim 1, characterized in that, The thickness of the composite grass mat is 12.3~17.5mm.

3. The composite grass mat according to claim 1, characterized in that, The aquatic plant leaves contain a porous structure with a pore diameter of 50~200μm; The compressed width of the aquatic plant leaf is 2.7~3.3cm, and the extended width is 4.5~5.5cm; the length of the aquatic plant leaf is 95~105cm; and the volumetric surface area of ​​the aquatic plant leaf is ≥1200m². 2 / m 3 ; The preparation method of the functional weft yarn includes the following steps: mixing high-density polyethylene and activated carbon and then extruding and pelletizing them with a twin-screw extruder to obtain a composite masterbatch; drawing the composite masterbatch into fibers and then twisting and plying them to obtain the functional weft yarn.

4. The composite grass mat according to claim 1 or 3, characterized in that, The biomimetic spiral anchor has a hollow structure, and the cavity of the hollow structure is filled with a mixture of cement and sand; The biomimetic spiral anchor has a pitch of 3.8~4.2cm; the surface of the biomimetic spiral anchor is provided with anti-slip protrusions, the height of which is 0.8~1.2mm. The biomimetic spiral anchor rod includes an insertion section and a connecting section. The length of the insertion section is 28-32cm, and the length of the connecting section is 8-12cm. The diameter of the biomimetic spiral anchor rod is 3.8-4.2cm.

5. The method for preparing the composite grass mat according to any one of claims 1 to 4, characterized in that, Includes the following steps: After the coconut fiber woven mesh is laid flat, it is covered with polylactic acid meltblown nonwoven fabric and then hot-pressed to form a support layer. The functional materials are dispersed in coconut shell fiber felt and then fixed in the first stage to obtain a water-retaining layer; The support layer, water-retaining layer and polylactic acid monofilament woven mesh are stacked from bottom to top and then fixed a second time to obtain the composite fiber blanket. The warp and weft threads are woven together to obtain aquatic plant leaves; the warp threads include polyester fibers or polypropylene fibers; the weft threads include main weft threads and functional weft threads, the main weft threads include polyester fibers or polypropylene fibers; the functional weft threads include high-density polyethylene fiber ropes loaded with activated carbon; one functional weft thread is set every two main weft threads. High-density polyethylene is injection molded to obtain a biomimetic spiral anchor rod; The aquatic plant leaves are fixed to the biomimetic spiral anchor rod and then inserted into the composite fiber blanket to obtain the composite grass blanket.

6. The preparation method according to claim 5, characterized in that, The hot pressing temperature is 160~170℃, the pressure is 0.28~0.32MPa, and the holding time is 28~32s; The first fixation method includes a first needling, the density of which is 14-16 needles / cm. 2 The depth of the first needle puncture is 9~11mm; The second fixing method includes: hot-pressing the support layer and the water-retaining layer together, and then performing a second needle punching on the hot-pressed product and the protective layer; the density of the second needle punching is 15~20 needles / cm. 2 ; The process after weaving also includes: heat-setting the woven product at a temperature of 120-130°C for 3-5 minutes. The injection molding conditions include: barrel temperature of 280~300℃, injection pressure of 60~80MPa, holding pressure of 40~50MPa, holding time of 25~35s, and mold temperature of 40~60℃.

7. The application of the composite vegetated mat according to any one of claims 1 to 4 or the composite vegetated mat prepared by the preparation method according to claim 5 or 6 in the restoration of damaged ecosystems in steep slope areas of lake and reservoir drawdown zones.

8. A method for restoring damaged ecosystems in steep slope areas of lake and reservoir drawdown zones, characterized in that, Includes the following steps: After dividing the steep slope area of ​​the lake and reservoir drawdown zone into a normally submerged zone, a wind and wave erosion zone, a slightly submerged zone, a composite grass mat was laid. The wind and wave erosion zone is the area within 0.5m above and below the normal water level. The normally submerged zone is the area below the wind and wave erosion zone to a water depth of 2m, and the water depth in the normally submerged zone is below 0.5m all year round. The slightly submerged zone is the area from the wind and wave erosion zone to the flood level. Submerged and emergent plants were respectively planted on composite grass mats in normally flooded and slightly flooded areas; the composite grass mat is the composite grass mat described in any one of claims 1 to 4 or the composite grass mat prepared by the preparation method described in claim 5 or 6.

9. The method for restoring damaged ecosystems in steep slope areas of lake and reservoir drawdown zones according to claim 8, characterized in that, The density of biomimetic fiber aquatic plants on the composite vegetation mat in the perpetually submerged area is 6-10 bundles / m². 2 The diameter of the holes for inserting the submerged plants is 180-220mm, and the number of submerged plants in each hole is 4-6. The holes are arranged in a triangular shape, and the distance between adjacent holes is 0.4-0.6m. The density of biomimetic fiber aquatic plants on the composite vegetation mat in the wave erosion zone is 16-36 bundles / m². 2 ; The density of biomimetic fiber aquatic plants on the composite vegetated mat in the lightly flooded area is 4-6 bundles / m². 2 The diameter of the holes for inserting the emergent plants is 180-220mm, and the number of emergent plants in each hole is 3-5. The holes are arranged in a triangular shape, and the distance between adjacent holes is 0.4-0.6m.

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