Ecological protection structure for mudflat and construction method

Abstract

The present application relates to the technical field of beach restoration and protection, and discloses a beach ecological protection structure and a construction method, wherein the beach ecological protection structure comprises a living energy dissipation zone, a pile foundation assembly and a vegetation zone which are sequentially arranged on the mean low water line of the beach; the living energy dissipation zone is arranged on the side close to the water area, and the vegetation zone is arranged on the side away from the water area; the mean low water line is taken as an absolute reference; the vegetation restoration, benthic animal restoration and beach protection are integrated in the dynamic-ecological window of the mean low water line; the ternary coupling of "structure-benthic-vegetation" is formed; the ecological nature of the beach protection is improved; and the ecological concept of "mainly relying on natural restoration and supplemented by artificial restoration" is realized.

Description

Technical Field

[0001] This invention relates to the field of tidal flat restoration and protection technology, specifically to tidal flat ecological protection structures and construction methods. Background Technology

[0002] Tidal flats are a general term encompassing beaches, riverbanks, and lakebanks. They refer to the tidal zone between high and low tide levels along the coast, the tidal flats between the normal and flood levels of rivers and lakes, the tidal flats below the seasonal flood level of lakes and rivers, and the tidal flat area between the normal storage level and the maximum flood level of reservoirs and ponds. Geomorphologically, this is called the "intertidal zone." Due to human activities such as reclamation and sand mining, sea-level rise, upstream water and sediment inflows, and invasive species, tidal flat wetland ecosystems are degrading, habitats are being lost and fragmented, and biodiversity is declining.

[0003] In existing technologies for tidal flat restoration, revetment structures such as groynes, concrete spur blocks, or submerged dikes are commonly used. These structures, to some extent, block biological pathways and exhibit ecological deficiencies such as hardening and bleaching. Summary of the Invention

[0004] This invention provides an ecological protection structure for tidal flats and a construction method therefor, in order to solve the problem of insufficient ecological protection in existing technologies for tidal flat restoration.

[0005] In a first aspect, the present invention provides a tidal flat ecological protection structure, comprising a living energy dissipation zone, a pile foundation component, and a vegetation belt arranged sequentially on the mean neap tide low tide line of the tidal flat, wherein the living energy dissipation zone is located on the side closer to the water, and the vegetation belt is located on the side farther from the water.

[0006] Beneficial effects: This invention uses the mean neap tide line as an absolute benchmark, integrating vegetation restoration, benthic animal recovery, and beach protection within the dynamic-ecological window of the mean neap tide line, forming a "structure-benthic-vegetation" ternary coupling, which improves the ecological nature of beach protection and realizes the ecological concept of "natural restoration as the main method and artificial restoration as a supplement".

[0007] In one alternative implementation, the live energy dissipation zone includes net cages and attachment bodies, with several net cages set on the mudflats and the attachment bodies set inside the net cages.

[0008] Beneficial effects: This invention adopts a dual coupling mechanism of net cages and attachment bodies. The attachment body, as a high-roughness attachment substrate, can induce clams, snails, and polychaete organisms to settle rapidly, forming a living energy dissipation layer and improving the ecology of the tidal flats.

[0009] In one alternative implementation, the live energy dissipation zone further includes a soft raft, which is positioned between the bottom net cage and the mudflat.

[0010] Beneficial effects: The invention's use of a soft raft at the bottom of the net cage can ensure the stability of the reef group and the beach surface.

[0011] In one alternative implementation, several net cages are arranged in a stepped manner on the mudflats.

[0012] Beneficial effects: The present invention sets the net cages in a stepped arrangement, which can utilize the maximum shear stress gradient at the mean neap tide low tide line to reduce wave energy and create conditions for oysters and clams to attach.

[0013] In one alternative implementation, the cage has an isolation layer on the side facing the shore.

[0014] Beneficial effects: The isolation layer in this invention can prevent soil erosion.

[0015] In one alternative embodiment, the pile foundation assembly includes a first pile foundation and a second pile foundation, the first pile foundation being arranged along the direction of water flow, and a plurality of second pile foundations being arranged obliquely on both sides of the first pile foundation, with the tops of the first pile foundation and the second pile foundation protruding above the water surface.

[0016] Beneficial effects: The pile foundation components of this invention provide benthic animals with a three-dimensional attachment surface and predator avoidance space, while also serving as a secondary wave damper and providing lateral support for seedlings in the vegetation zone, significantly improving vegetation survival rate. The first and second pile foundations form a multi-level slow-flow corridor, which can be utilized by species with different hydrodynamic preferences (filter feeders, sediment feeders); at the same time, the second pile foundation forms a bifurcated wave damper, further dissipating energy and reducing reflected waves.

[0017] In one alternative implementation, the first pile foundation includes vertical piles, a plurality of which are arranged in a circle within the mudflats.

[0018] Beneficial effects: The vertical piles of this invention and the slow-flow zone between the piles provide a three-dimensional attachment surface and space for avoiding enemies.

[0019] In one alternative embodiment, the angle between the second pile foundation line and the first pile foundation line is 40° to 50°.

[0020] In one alternative implementation, the vegetation strip includes cultivated soil and plants, with the cultivated soil set at the bottom of the tidal flat and the plants planted in the cultivated soil.

[0021] Beneficial effects: Planting in this invention can help protect and stabilize the beach, and provide shelter for organisms. Backfilling the planting area with topsoil before planting can improve the survival rate of seedlings.

[0022] Secondly, the present invention also provides a method for constructing an ecological protection structure for tidal flats, applicable to the aforementioned ecological protection structure for tidal flats, the method comprising: Obtain the mean neap tide line of the mudflats and use the mean neap tide line as the zero elevation. A living energy dissipation zone, pile foundation components, and a vegetation zone are sequentially set along the mean neap tide line; Soft rafts are set up on the mudflats, and the net cages are arranged in a stepped manner on the soft rafts; The pile foundation components were placed in the tidal flats; The topsoil is placed on the mudflats, and plants are grown in the topsoil. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a cross-sectional schematic diagram of a tidal flat ecological protection structure according to an embodiment of the present invention; Figure 2 This is an unfolded diagram of a net cage in a tidal flat ecological protection structure according to an embodiment of the present invention; Figure 3 for Figure 2 A magnified view of part A in the diagram; Figure 4 This is a three-dimensional structural diagram of a net cage in a tidal flat ecological protection structure according to an embodiment of the present invention; Figure 5 This is a plan view of the pile foundation components in a tidal flat ecological protection structure according to an embodiment of the present invention; Figure 6 This is a flowchart illustrating the method for constructing an ecological protection structure for tidal flats according to an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures: 1. Live energy dissipation zone; 11. Net cage; 12. Attachment body; 13. Soft drain; 14. Isolation layer; 2. Pile foundation components; 21. First pile foundation; 22. Second pile foundation; 3. Vegetation zone; 31. Plants; 32. Topsoil. Detailed Implementation

[0026] 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 only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In related technologies, when constructing protective structures for tidal flats, the top elevation is usually based on the multi-year average high tide level or the design high tide level, with the main structure located on the mid-to-high tide tidal flats 0.5m to 1.0m above the average tide level; or, based on the empirical formula of "wave-breaking point outward movement," submerged breakwaters or riprap bodies are placed underwater at a location 100m to 300m from the shore and below the tidal flat elevation of -1.0m. This positioning method has the following drawbacks: 1. It often results in "over-protection of high tidal flats and a lack of protection for low tidal flats," with erosion hotspots concentrated near the average neap tide line; 2. Using the "high tide level" or "wave-breaking point" as a benchmark leads to large errors in on-site measurements, requiring multiple on-site verifications and limiting the construction window; 3. The structural elevation is fixed and cannot be adaptively adjusted with the natural siltation of the tidal flats, resulting in frequent maintenance in the later stages; 4. The structural materials are mostly rigid, lacking in ecological and environmental friendliness.

[0028] The following is combined with Figures 1 to 6 The following describes embodiments of the present invention.

[0029] According to embodiments of the present invention, in one aspect, such as Figures 1 to 5 As shown, a tidal flat ecological protection structure is provided, including a living energy dissipation zone 1, a pile foundation component 2, and a vegetation belt 3 arranged sequentially on the mean neap tide low tide line of the tidal flat. The living energy dissipation zone 1 is located on the side closer to the water, and the vegetation belt 3 is located on the side farther away from the water.

[0030] Specifically, in this embodiment, the Mean Low Water Neaps (MLWN) is taken as the "zero elevation". On this dividing zone, a living energy dissipation zone 1, a pile foundation component 2 and a vegetation zone 3 are set in sequence. The living energy dissipation zone 1 is located on the side closer to the water, and the vegetation zone 3 is located on the side closer to the shore.

[0031] In this embodiment, the living energy dissipation zone 1 is used to form a living energy dissipation layer for clams, snails, and polychaetes, utilizing the maximum shear stress gradient at the mean neap tide low water line (MLWN) to reduce wave energy and create conditions for oysters and clams to attach. The pile foundation component 2 can provide a three-dimensional attachment surface and predator avoidance space for benthic animals, and can also play a secondary wave dissipation role, providing lateral support for seedlings in the vegetation zone 3 and improving the survival rate of plants 31.

[0032] In this embodiment, the living energy dissipation zone 1 can induce benthic animals to survive, the pile foundation component 2 can dissipate waves and protect seedlings, and the vegetation belt 3 can stabilize the beach, forming a ternary coupling of "structure-benthic-vegetation" to achieve a natural transition from "artificial structure to natural reef" and embody the ecological concept of "natural restoration as the main method and artificial restoration as a supplement".

[0033] This invention uses the mean neap tide line as an absolute benchmark, integrating vegetation restoration, benthic animal recovery, and beach protection within the dynamic-ecological window of the mean neap tide line, forming a "structure-benthic-vegetation" ternary coupling, which improves the ecological nature of beach protection and realizes the ecological concept of "natural restoration as the main method and artificial restoration as a supplement".

[0034] In one embodiment, such as Figures 1 to 4 As shown, the live energy dissipation zone 1 includes net cages 11 and attachment bodies 12. Several net cages 11 are set on the mudflats, and the attachment bodies 12 are set inside the net cages 11.

[0035] Specifically, this embodiment does not impose any specific limitations on the net cage 11. For example, in this embodiment, the net cage 11 is a gabion net cage 11. Each gabion net cage 11 has a size of 1.0m (length) × 1.0m (width) × 0.5m (height), a mesh size of 60mm × 80mm, and is made of Φ2.2mm low carbon steel wire with a surface galvanized aluminum alloy. The four corners of the net cage 11 are provided with quick-connect hooks, which can be assembled by hand underwater to realize the interconnection of adjacent net cages 11.

[0036] In this embodiment, the attachment body 12 is not specifically limited. For example, in this embodiment, the attachment body 12 adopts an oyster shell-shell composite. The oyster shell-shell composite consists of 70% intact oyster shells (long axis 80mm to 120mm) + 30% broken shells (10mm to 30mm), with a surface roughness Ra≥500μm, providing a high-roughness attachment substrate to induce clams, snails, and polychaete organisms to settle rapidly and form a "living energy dissipation layer".

[0037] This invention employs a dual coupling mechanism of net cage 11 and attachment body 12. The attachment body 12, as a high-roughness attachment substrate, can induce clams, snails, and polychaete organisms to settle rapidly, forming a living energy dissipation layer and improving the ecology of the tidal flat.

[0038] In one embodiment, such as Figure 1 As shown, the live energy dissipation zone 1 also includes a soft rack 13, which is located between the bottom net cage 11 and the mudflat.

[0039] Specifically, in this embodiment, the soft row 13 is not specifically limited. For example, in this embodiment, the soft row 13 is a sand-ribbed soft row 13.

[0040] The present invention provides a soft rack 13 at the bottom of the net cage 11 to ensure the stability of the reef group and the beach.

[0041] In one embodiment, such as Figure 1 As shown, several net cages 11 are arranged in a stepped manner on the mudflats.

[0042] Specifically, in this embodiment, the cages 11 are arranged in a stepped, upright manner, with three layers from bottom to top. The top elevation of the first layer of cages 11 is controlled according to the measured average neap tide line. Four to six cages 11 can be arranged in the first layer. The second and third layers of cages 11 have one to two fewer cages than the lower layer, and the cages 11 are arranged in the center.

[0043] The present invention arranges the net cage 11 in a "stepped-finger" pattern, which can utilize the maximum shear stress gradient at the mean neap tide low tide line to reduce wave energy and create conditions for oysters and clams to attach.

[0044] In one embodiment, such as Figure 1 As shown, the cage 11 has an isolation layer 14 on the side facing the shore.

[0045] Specifically, the isolation layer 14 is not specifically limited in this embodiment. For example, in this embodiment, the isolation layer 14 is made of geotextile. Geotextile is installed on the bank side of the gabion 11 assembly. Geotextile allows water to pass through and can also isolate sand and soil, thus preventing soil erosion.

[0046] In one embodiment, such as Figure 5 As shown, the pile foundation assembly 2 includes a first pile foundation 21 and a second pile foundation 22. The first pile foundation 21 is arranged along the water flow direction, and a number of second pile foundations 22 are arranged obliquely on both sides of the first pile foundation 21. The tops of the first pile foundation 21 and the second pile foundation 22 are exposed above the water surface.

[0047] Specifically, in this embodiment, the pile foundation component 2 is located 0.8m to 1.0m behind the cage 11 component, and the top elevation of the pile foundation component 2 is MLWN + 1.5m, ensuring that it can still be exposed above the water surface during high tide.

[0048] In this embodiment, the first pile foundation 21 and the second pile foundation 22 are arranged in a fishbone pattern on the plane. Several first pile foundations 21 are arranged at 1.0m intervals along the water flow direction (adjustment allowed by ±0.2m). Several second pile foundations 22 are arranged symmetrically on both sides of each first pile foundation 21, forming a fishbone shape. The length of the line connecting the top of one side of the second pile foundation 22 to the center of the first pile foundation 21 is 1.4m to 1.5m. On the oblique branches, the second pile foundations 22 are arranged individually at 0.2m intervals.

[0049] The pile foundation component 2 of this invention, along with the slow-flow zone between piles, provides a three-dimensional attachment surface and enemy avoidance space. The herringbone layout branches in a "main bone-oblique branch" pattern along the main flow direction, forming multi-level slow-flow corridors. Different hydrodynamic preferences (filter feeders and sediment feeders) can utilize these corridors in designated areas. Simultaneously, a "main bone-oblique branch" wave-dissipating barrier is formed, further dissipating energy and reducing reflected waves, and providing lateral support for seedlings in the vegetation zone 3, significantly improving the survival rate of plants 31 at 0.3m to 0.6m above the MLWN. The first pile foundation 21 and the second pile foundation 22 form multi-level slow-flow corridors, allowing different hydrodynamic preferences (filter feeders and sediment feeders) to utilize them in designated areas. Simultaneously, the second pile foundation 22 forms a bifurcated wave-dissipating barrier, further dissipating energy and reducing reflected waves.

[0050] In one embodiment, the first pile foundation 21 includes vertical piles, and a plurality of vertical piles are arranged in a circle in the mudflat.

[0051] Specifically, in this embodiment, the first pile foundation 21 consists of a vertical pile arranged with a radius of 0.2m in each of the eight directions of the circle, at the center.

[0052] In this embodiment, the vertical pile and the second pile foundation 22 can be made of bamboo piles with a diameter of 8cm to 10cm, a length of 2m to 6m, and a pile top elevation of MLWN + 1.5m.

[0053] The present invention provides a three-dimensional attachment surface and enemy avoidance space for the vertical pile itself and the slow flow zone between the piles.

[0054] In one embodiment, the angle between the line connecting the second pile foundation 22 and the line connecting the first pile foundation 21 is 40° to 50°.

[0055] Specifically, in this embodiment, the second pile foundation 22 of the "oblique branch" is at a 45° angle to the first pile foundation 21 of the "main bone".

[0056] In one embodiment, such as Figure 1 As shown, the vegetation zone 3 includes cultivated soil 32 and plants 31. The cultivated soil 32 is set at the bottom of the tidal flat, and the plants 31 are planted in the cultivated soil 32.

[0057] Specifically, in this embodiment, beach plants 31 are planted behind the fishbone-shaped pile foundation component 2. In this embodiment, the plants 31 are not specifically limited. For example, the plants 31 can be reeds, salt-tolerant plants, sea buckthorn, etc., which play a role in protecting and stabilizing the beach and providing shade for aquatic organisms to avoid the elements. Before planting the plants 31, the planting area is backfilled with cultivated soil 32 with a backfill thickness of 0.3m to 0.5m to improve the survival rate of the plant seedlings 31.

[0058] In this invention, planting plants 31 can help protect and stabilize the beach and provide shelter for organisms. Before planting, backfilling the planting area with cultivated soil 32 can improve the survival rate of the seedlings.

[0059] According to an embodiment of the present invention, on the other hand, such as Figure 6 As shown, a method for constructing an ecological protection structure for tidal flats is also provided, which is applied to the aforementioned ecological protection structure for tidal flats. The construction method includes: Obtain the mean neap tide line of the mudflats and use the mean neap tide line as the zero elevation. A living energy dissipation zone 1, pile foundation components 2, and vegetation belt 3 are sequentially set along the mean neap tide low tide line; A soft raft 13 is set up on the mudflats, and the net cages 11 are set up on the soft raft 13 in a stepped manner; The pile foundation component 2 is placed in the tidal flat; The cultivated soil 32 is placed on the tidal flat, and plants 31 are planted in the cultivated soil 32.

[0060] Specifically, in this embodiment, when constructing the tidal flat ecological protection structure, the average neap tide line measured on-site is taken as the "zero elevation", and a living energy dissipation zone 1, pile foundation components 2 and vegetation belt 3 are set up in this dividing zone.

[0061] In this embodiment, when setting up the living energy dissipation zone 1, a soft raft 13 is first set up on the mudflat, and then the net cages 11 are arranged vertically in a stepped manner. The net cages 11 are arranged in three layers from bottom to top. The top elevation of the first layer of net cages 11 is controlled according to the measured average neap tide line. There are 4 to 6 net cages 11 in the first layer. The second and third layers of net cages 11 are reduced by 1 to 2 compared with the lower layer. The net cages 11 are arranged in the center. The net cages 11 are filled with an attachment body 12, and geotextile is set on the shore side of the net cages 11.

[0062] In this embodiment, when setting up the pile foundation component 2, the first pile foundation 21 is set 0.8m to 1.0m behind the gabion 11 component. The first pile foundation 21 is arranged at 1.0m intervals along the main bone direction. Each first pile foundation 21 has one vertical pile arranged in the center and eight directions of the circle. The second pile foundation 22 is arranged symmetrically on both sides of each first pile foundation 21 in a fishbone shape, at 45° with the main bone direction. The length of the branch on one side is 1.4m to 1.5m. The second pile foundation 22 is arranged individually at 0.2m intervals.

[0063] In this embodiment, plants 31 are planted behind the pile foundation component 2. Before planting, the planting area is backfilled with topsoil 32 with a backfill thickness of 0.3m to 0.5m.

[0064] This invention fully considers the characteristics of the mean neap tide line as the boundary between mid-tide and low-tide shoals, including "strong hydrodynamic shear and erosion sensitivity," "the richest foraging zone for benthic animals and the most important energy supply zone for migratory birds," and "the lower boundary for stable growth of salt marsh vegetation." It uses the mean neap tide line as an absolute benchmark, integrating vegetation restoration, benthic animal recovery, and beach protection within the dynamic-ecological window of the mean neap tide line. It directly uses the field-measured mean neap tide line as the absolute benchmark, avoiding errors caused by the superposition of empirical coefficients.

[0065] This invention employs a dual coupling mechanism of gabion cages, shells / bamboo, and vegetation. The oyster shell-shell composite within cage 11 provides a high-roughness attachment substrate, inducing clams, snails, and polychaetes to quickly settle, forming a "living energy-absorbing layer." The fishbone-shaped bamboo stakes provide a three-dimensional attachment surface and predator avoidance space for benthic animals, while also acting as a secondary wave absorber and providing lateral support for the seedlings of salt marsh plant 31, significantly improving the survival rate of vegetation 0.3m to 0.6m above the MLWN (Medium-Range Weir). The structural gabion portion of cage 11 remains stable over the long term. The bamboo gradually decomposes into organic matter over 3 to 5 years, eventually being completely replaced by the root system of plant 31 and the shell reef system. The oyster shell-shell system induces benthic animals, the bamboo stakes absorb waves and protect seedlings, and the salt marsh vegetation stabilizes the beach, forming a ternary coupling of "structure-benthic-vegetation," achieving a natural transition from "artificial structure to natural reef," embodying the ecological concept of "primarily natural restoration, supplemented by artificial restoration."

[0066] This invention uses a foldable net cage 11 for quick connection and bamboo stakes for manual installation. It can complete a 100-meter-long project within 48 hours of spring neap tide, without the need for large equipment on site, and significantly reduces the ecological disturbance to the intertidal zone.

[0067] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A tidal flat ecological protection structure, characterized in that, include: A living energy dissipation zone (1), a pile foundation assembly (2), and a vegetation belt (3) are sequentially set on the mean neap tide low tide line of the tidal flat. The living energy dissipation zone (1) is set on the side closer to the water, and the vegetation belt (3) is set on the side farther away from the water.

2. The tidal flat ecological protection structure according to claim 1, characterized in that, The living energy dissipation zone (1) includes: Net cages (11), a plurality of said net cages (11) are set on the mudflats; An attachment body (12) is disposed inside the cage (11).

3. The tidal flat ecological protection structure according to claim 2, characterized in that, The living energy dissipation zone (1) also includes: A soft rack (13) is installed between the bottom net cage (11) and the mudflat.

4. The tidal flat ecological protection structure according to claim 2 or 3, characterized in that, Several of the net cages (11) are arranged in a stepped manner on the mudflats.

5. The tidal flat ecological protection structure according to claim 2 or 3, characterized in that, The cage (11) has an isolation layer (14) on the side facing the shore.

6. The tidal flat ecological protection structure according to claim 5, characterized in that, The pile foundation assembly (2) includes: The first pile foundation (21) is arranged along the direction of water flow; The second pile foundation (22) is located on both sides of the first pile foundation (21) and arranged obliquely. The tops of the first pile foundation (21) and the second pile foundation (22) are exposed above the water surface.

7. The tidal flat ecological protection structure according to claim 6, characterized in that, The first pile foundation (21) includes: Vertical piles, a plurality of which are arranged in a circle in the mudflats.

8. The tidal flat ecological protection structure according to claim 6, characterized in that, The angle between the line connecting the second pile foundation (22) and the line connecting the first pile foundation (21) is 40° to 50°.

9. The tidal flat ecological protection structure according to claim 1, characterized in that, The vegetation zone (3) includes: Topsoil (32), which is placed at the bottom of the tidal flat; Plant (31), which is planted in the cultivated soil (32).

10. A method for constructing an ecological protection structure for tidal flats, characterized in that, The method for constructing the tidal flat ecological protection structure applied to any one of claims 1 to 9 includes: Obtain the mean neap tide line of the mudflats and use the mean neap tide line as the zero elevation. A living energy dissipation zone (1), pile foundation components (2), and vegetation belt (3) are set sequentially along the mean neap tide line. Soft rafts (13) are set up on the mudflats, and net cages (11) are set up on the soft rafts (13) in a stepped manner; The pile foundation assembly (2) is placed in the tidal flat; The cultivated soil (32) is placed on the tidal flat, and plants (31) are planted in the cultivated soil (32).

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