Environment compatible type ecological submerged dike construction method suitable for pelagic coral island coast protection

Abstract

The invention provides an environment compatible type ecological submerged dike construction method suitable for pelagic coral island coast protection, and relates to the technical field of pelagic coral island coast protection and coral reef ecological restoration, and the method comprises the following steps: respectively obtaining terrain information, hydrodynamic information and ecological information of a target area; submerged dike structure information, submerged dike depth information and submerged dike material information are determined through numerical simulation analysis and a physical model test; and according to the submerged dike structure information, the submerged dike depth information and the submerged dike material information, constructing a submerged dike in the target area. The ecological submerged dike can be constructed on a narrow reef or a shallow reef slope, so that the marginal reef terrain with a reef crown structure is artificially reproduced, better wave dissipation and wave resistance are provided for the narrow, longitudinal and deep reef, meanwhile, a proper habitat is provided for marine organisms, and attachment and growth of the marine organisms are promoted.

Description

Technical Field

[0001] This invention relates to the field of offshore coral island and reef coastal protection and coral reef ecological restoration technology, and in particular to a method for constructing an environmentally compatible ecological submerged dam suitable for offshore coral island and reef coastal protection. Background Technology

[0002] The South China Sea is a high-risk area for disastrous typhoons and storm surges, and the islands and reefs along the coast face extreme natural disasters and long-term erosion and scouring processes from natural forces (including wind, waves, currents, and tides). Degradation of the island and reef bio-coasts leads to the loss of the original reef-building organisms on the reef flats, which cannot provide seafloor friction to dissipate wave energy, resulting in reef flat erosion and degradation, and wave intrusion on the island and reef coastlines. Many of the islands and reefs in the South China Sea are offshore coral reefs. Offshore coral reefs are characterized by fragile ecosystems, narrow reef platforms making it difficult for large engineering machinery to operate, and the challenges of mobilizing engineering resources, short construction and maintenance windows, and harsh and variable marine environments, further exacerbating the economic and human costs of island and reef ecological protection projects. Therefore, developing environmentally compatible ecological protection technologies for coral reef coastlines to enhance the physical disaster resistance of the coast and constructing environmentally compatible ecological coastlines is of significant practical and strategic importance for maintaining my country's ecological security in the South China Sea and national security.

[0003] Coral reef ecosystems, often called the rainforests of the ocean, are the lifeblood and protectors of coral islands and reefs. They play a vital ecological role in protecting islands and reefs, significantly reducing storm and typhoon damage, mitigating erosion from ocean currents and waves, replenishing lost sand and gravel, stabilizing reef structures, and creating habitable environments. Coral island and reef coastlines are primarily constructed by organisms. Nearshore coral reef ecosystems, built from animal secretions, bones, and remains, are areas of highly concentrated biological activity and are considered critical coastal ecological zones. In particular, framework reef-building organisms, primarily reef-building corals, play an irreplaceable role in the healthy development of reef structures. Therefore, restoring and maintaining coral reef ecosystems and reviving their biotidal coastal ecosystem services is a key focus in safeguarding my country's national interests.

[0004] Traditional island and reef coastal protection breakwater systems often fail to effectively dissipate wave energy. For remote islands and reefs with narrow reef flats or shallow reef slopes, the material, hydrodynamic, and structural designs of traditional breakwater systems lack consideration for the risk of reef failure and damage, failing to address this issue from the perspective of hydraulic structure design standards. In recent years, international engineering experiments on traditional concrete breakwaters have incorporated structural designs conducive to coral cover; however, these designs have not adequately considered the surface, internal topology, and material composition of the breakwater, making it difficult to fully meet requirements for structural strength and environmental compatibility. Internationally, the development of novel environmentally compatible ecological protection technologies that comprehensively consider wave protection, shoreline protection, and biocompatibility is still in the preliminary research stage. Summary of the Invention

[0005] To address the problems in existing technologies, this invention provides a method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea. This method can construct ecological submerged dams on narrow reef flats or shallow reef slopes to artificially reproduce the topography of marginal reefs with reef crowns, providing better wave dissipation and wave resistance performance for narrow and deep reef flats, while providing a suitable habitat for marine life and promoting the attachment and growth of marine organisms.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea includes the following steps:

[0008] The topographic, hydrodynamic and ecological information of the target area was obtained respectively, and the structural, depth and material information of the submerged dam were determined through numerical simulation analysis and physical model test.

[0009] Based on the submerged dam structure information, the submerged dam depth information, and the submerged dam material information, a submerged dam is constructed within the target area.

[0010] The environmentally compatible ecological submerged dam construction method applicable to offshore coral island and reef coastal protection, as described above, further includes the topographic information of the target area, which includes the planar outline information of the coral island and reef and the reef flat elevation change information.

[0011] The planar contour information of the coral reef includes the long axis direction information of the coral reef and the width information of the reef platform.

[0012] The long axis direction information of the coral reef is measured by auxiliary equipment to determine the angle between the submerged bar axis and the dominant wave direction;

[0013] The width of the reef platform of the coral islands and reefs is measured by auxiliary equipment, and the compactness index is obtained by combining the reef platform area. The density of the submerged bar layout is determined based on the compactness index.

[0014] The reef flat elevation change information includes reef flat surface elevation information and surrounding sea area water depth information;

[0015] The elevation information of the reef flat surface and the water depth information of the surrounding sea area are measured by auxiliary equipment, and the relative height difference is calculated according to a preset formula to determine the reference surface of the submerged dam.

[0016] The environmentally compatible ecological submerged dam construction method for offshore coral island and reef coastal protection, as described above, further includes hydrodynamic information of the target area, including flow characteristics, wave characteristics, and tidal characteristics.

[0017] The water flow characteristic information includes flow velocity and flow direction information and water flow type information;

[0018] The flow velocity and flow direction information are monitored by auxiliary equipment to obtain average flow velocity information, maximum flow velocity information and flow direction distribution information. The slope of the submerged dam is determined based on the obtained average flow velocity information, maximum flow velocity information and flow direction distribution information.

[0019] The water flow type information is monitored by auxiliary equipment to obtain tidal flow information, residual flow information and wave-induced flow information. Based on the obtained tidal flow information, residual flow information and wave-induced flow information, the location of the submerged dam is determined through simulation experiments.

[0020] The wave characteristic information includes wave element information and wave type information;

[0021] The wave element information is monitored by auxiliary equipment to obtain effective wave height, wave period and wave direction information. The dam height of the submerged dam is determined based on the obtained effective wave height, wave period and wave direction information.

[0022] The wave type information is obtained by monitoring wind wave information, swell information and mixed wave information through auxiliary equipment. Based on the obtained wind wave information, swell information and mixed wave information, the wave-facing structure of the submerged dam is determined through simulation experiments.

[0023] The tidal characteristic information includes tidal type information, tidal level parameter information, and tidal range information;

[0024] The tidal type information is obtained by acquiring semi-diurnal and diurnal tidal information from historical records. The weight of the submerged dam is determined by simulation experiments based on the acquired semi-diurnal and diurnal tidal information.

[0025] The tidal level parameter information is monitored and obtained through auxiliary equipment, including the highest tide level, the lowest tide level, and the average tide level. The top elevation of the submerged dam is determined through simulation experiments based on the highest tide level information, the burial depth of the submerged dam is determined through simulation experiments based on the lowest tide level information, and the centerline elevation of the submerged dam is determined through simulation experiments based on the average tide level information.

[0026] The tidal range information is obtained through historical records of spring tide and neap tide, and the local structure of the submerged dam is determined through simulation experiments based on the obtained spring tide and neap tide information.

[0027] The environmentally compatible ecological submerged dam construction method applicable to offshore coral island and reef coastal protection, as described above, further includes the following ecological information for the target area: coral species and distribution information and coral reef health status information.

[0028] The coral species and distribution information includes coral type information, coral coverage information, and coral growth rate information;

[0029] The coral type information is monitored and obtained through auxiliary equipment to acquire reef-building coral adaptation information or soft coral adaptation information;

[0030] The coral coverage information is monitored and high-coverage area information and low-coverage area information are obtained through auxiliary equipment;

[0031] The coral growth rate information is monitored and acquired through auxiliary equipment, including information on fast-growing corals and slow-growing corals.

[0032] The coral reef health status information is monitored and acquired through auxiliary equipment, including information on bleaching risk areas and disease / damage areas.

[0033] Based on the obtained information on reef-building coral compatibility or soft coral compatibility, high coverage area information, low coverage area information, fast-growing coral information, slow-growing coral information, bleaching risk area information, and disease and damage area information, the material of the dam body is determined through simulation experiments and the construction of physical models.

[0034] The environmentally compatible ecological submerged dam construction method applicable to offshore coral island and reef coastal protection, as described above, further includes the following steps in the numerical simulation analysis:

[0035] The topographic information of the target area is input into computer software to simulate the response of submerged dams of different structural forms under the topographic conditions and hydrodynamic action of the target area, and the simulation results are obtained.

[0036] Different simulation results are compared with preset results, and the simulation result that best matches the preset results is selected as the submerged dam structure information.

[0037] The environmentally compatible ecological submerged dam construction method for offshore coral reef coastal protection, as described above, further includes the following steps in the physical model test:

[0038] A submerged dam model is created according to a preset scale based on the terrain information of the target area.

[0039] The submerged dam model was placed in a laboratory water tank or wave pool for testing to simulate hydrodynamic conditions and obtain simulation results.

[0040] Different simulation results are compared with preset results, and the simulation result that best matches the preset results is selected as the submerged dam structure information.

[0041] The environmentally compatible ecological submerged dam construction method applicable to offshore coral island and reef coastal protection, as described above, further involves, after constructing the submerged dam in the target area, using reef-building organisms to establish themselves at the bottom of the submerged dam based on the obtained topographic and ecological information. The establishment methods include cutting fixation, binding fixation, adhesive fixation, or modular fixation.

[0042] Cutting and fixing method: In the main body of the submerged dam, the connection area between dam bodies and the adjacent extended ecological restoration area, the substrate with natural or artificial gaps is embedded and sown.

[0043] Binding and fixing method: Functional biological binding and planting is carried out on the surface of the submerged dam body and the connecting modules between the dam bodies. The planting area is pre-embedded or installed with branch-shaped protrusions, T-shaped or ring-shaped structural components that can be used for binding of functional biological components to meet the requirements of biological binding and fixing. The structural components are made of one of stainless steel, cast iron, bioceramics or basalt fiber. The functional biological components are made of one of metal wire, metal buckle or biodegradable strip.

[0044] Adhesive fixing method: Sowing and planting are carried out on the other parts of the dam body except for the debris base in the extended ecological restoration area;

[0045] Modular fixing method: Based on the water depth, substrate structure, environmental suitability of functional organisms and spatial ecological niche of the planting area, the single or multiple functional organisms to be planted are first combined and fixed on the basic module. After intermediate cultivation or in-situ acclimatization steps to allow the functional organisms to adapt to the habitat conditions of the planting area and reach the size and health status for bottom seeding, they are planted together with the basic module on the submerged dam body, the connecting modules between dam bodies and the hard substrate of the extended ecological restoration area. The overall planting module is fixed with adhesive or pre-embedded components.

[0046] The environmentally compatible ecological submerged dam construction method applicable to offshore coral island and reef coastal protection, as described above, further involves, after constructing the submerged dam in the target area, using a combination of single or multiple functional organisms and a planting method based on the obtained hydrodynamic information, to construct the environmentally compatible ecological submerged dam.

[0047] When targeting the connection zone between shallow reef flats and dams with strong dynamic effects in shallow water (less than 2m), hard coral reef rocks, and clastic substrates, as well as the extended ecological restoration area, a modular fixation method for calcified coral algae is adopted to carry out environmentally suitable planting.

[0048] When targeting the connection area between dams and the extended ecological restoration area of ​​hard coral reefs and debris bottoms without large structural components at a water depth of 4-8m, environmentally suitable combination planting methods are adopted, including modular fixing method of calcified coral algae, cutting fixing method, and fixing method of reef-building coral adhesive.

[0049] When targeting the top area of ​​the submerged dam body in the 0-3m range, the modular fixing method and adhesive fixing method are used to carry out bottom seeding and planting of reef-building shellfish, and the modular fixing method of reef-building corals is combined with environmentally suitable combination planting.

[0050] When targeting the vertical facade area in the middle of the submerged dam body of 3-5m, the adhesive fixing method is used to carry out combined bottom seeding and planting of reef-building corals and calcified coral algae.

[0051] When targeting the horizontal elevation of the middle section of the submerged dam body (3-5m) and the lower section of the submerged dam body (5-8m), a combination of adhesive fixing and modular fixing methods is used for bottom seeding and planting, primarily using reef-building corals and combined with other reef-building and protective organisms.

[0052] The environmentally compatible ecological submerged dam construction method applicable to coastal protection of coral islands and reefs in the open sea, as described above, is further described in that the submerged dam is formed by splicing together several modules of different shapes. The modules of different shapes are prefabricated using reinforced concrete material and cast using steel formwork. The surfaces of the modules of different shapes are provided with threaded sleeves. The modules of different shapes include Z-shaped modules, L-shaped modules, T-shaped modules, flat modules, pointed modules, cuboid modules, and hexahedral modules.

[0053] The cuboid module is provided with trapezoidal mating teeth, the hexahedral module has a mating interface on its side, and the upper surface of the hexahedral module is provided with a mating ring, and the mating interface is adapted to the mating ring.

[0054] The environmentally compatible ecological submerged dam construction method applicable to offshore coral island and reef coastal protection, as described above, further includes several modules of different shapes having microporous structures and parallel microgroove structures to form a biocompatible reef base surface geometry.

[0055] The microporous structure has a pore diameter of 1-4 mm and a pore depth of 1-2 mm; the parallel microgroove structure has a groove width of 2-5 mm and a groove depth of 1.5-3 mm.

[0056] Compared with the prior art, the advantages of this invention are as follows:

[0057] This invention can construct ecological submerged dams on narrow reef flats or shallow reef slopes to artificially reproduce marginal reef topography with reef crown structures, providing better wave dissipation and wave resistance performance for narrow and deep reef flats, while providing a suitable habitat for marine life and promoting the attachment and growth of marine organisms. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of the structure of the environmentally compatible ecological submerged dam simulating the natural reef crown topography at the top of the outer reef slope in an embodiment of the present invention;

[0060] Figure 2 This is a schematic diagram of the structure of the dam section in Mode 1 of this invention;

[0061] Figure 3 This is a schematic diagram of the structure of the dam section in Mode 2 of this invention.

[0062] Figure 4 This is a schematic diagram of the structure of the dam section in Mode 3 of this embodiment of the invention;

[0063] Figure 5 This is a schematic diagram of the Z-type module in an embodiment of the present invention;

[0064] Figure 6 This is a schematic diagram of the L-shaped module in an embodiment of the present invention;

[0065] Figure 7 This is a schematic diagram of the structure of the flat panel module in an embodiment of the present invention;

[0066] Figure 8 This is a schematic diagram of the T-shaped module in an embodiment of the present invention;

[0067] Figure 9 This is a schematic diagram of the structure of the pointed-corner module in an embodiment of the present invention;

[0068] Figure 10 This is a schematic diagram of the hexahedral module in an embodiment of the present invention;

[0069] Figure 11 This is a schematic diagram of the cuboid module in an embodiment of the present invention;

[0070] Figure 12 This is a schematic diagram of the structure of the ecological dam material accessories in an embodiment of the present invention;

[0071] Figure 13 This is a schematic diagram of the structure of the ecological dam material accessories in an embodiment of the present invention. Detailed Implementation

[0072] 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 this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0073] Example:

[0074] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, in the embodiments of this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0075] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0076] In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0077] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0078] This invention provides a technical solution: a method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, comprising the following steps: acquiring topographic information, hydrodynamic information, and ecological information of the target area respectively, and determining the submerged dam structure information, submerged dam depth information, and submerged dam material information through numerical simulation analysis and physical model tests; and constructing the submerged dam in the target area based on the submerged dam structure information, submerged dam depth information, and submerged dam material information.

[0079] Specifically, in shallow waters near the shoreline requiring protection, impermeable dams with rectangular or trapezoidal cross-sections are deployed. These dams are submerged during normal operation. The wave-dissipating and shoreline-protecting mechanism of these submerged dams primarily involves reflecting wave energy and stimulating premature wave breakage, thereby increasing wave energy dissipation. However, in coral reef environments, due to the abrupt changes in reef topography, if the submerged breakwater is deployed too deep, it has almost no wave-dissipating effect; if deployed too shallow, the dam section cross-section is too small, resulting in insufficient wave resistance. Based on a typical reef topography (i.e., fringing reef with reefcrest), and combining the design concept of submerged breakwater structures with the principle of biomimicry, an environmentally compatible ecological submerged dam is constructed on narrow reef flats or shallow reef slopes without reef crowns, thus artificially reproducing fringing reef topography with reef crowns (see...). Figure 1 ).

[0080] Based on the above design concept, this invention adopts a design scheme of assembling and connecting multiple small modules into a complete environmentally compatible ecological submerged dam structure. According to the width and slope of the reef flat / shallow reef slope, a multi-layered dam section structure is adopted, with counterweight modules connecting the dam sections. The number of dam section layers needs to be assessed on-site based on the conditions of the constructable reef flat base and the required wave dissipation effect. Interlocking and connectors between modules are used to improve the wave dissipation performance and stability under extreme wave conditions. Based on the construction requirement of minimizing ecosystem impact, and considering the construction conditions of shallow-water reef flats and diving operations, the basic data for a single module are as follows: b. Single module: volume ≤ 1.5m³, weight ≤ 3.5t; a. Single-layer dam: length ≤ 4.5m, single-row width ≤ 1.6m.

[0081] The environmentally compatible ecological submerged dam structure model of the present invention can adopt, but is not limited to, the following basic dam construction models ( Figures 2 to 4 Among them, the basic unit module data of the Mode 2 dam section (see...) Figures 5 to 11 (As shown in Table 1), D2-M4-5 (pointed-angle module) and D2-M5-5 (flat plate module) are used as bottom pads for leveling the base of the dam section and adjusting the slope. D2-M1-5 (Z-type module), D2-M2-5 (L-type module), and D2-M3-5 (T-type module) are the main modules. Each module is equipped with pre-embedded connectors, which can connect the dam modules and the double-layer dam sections, further enhancing wave resistance. The overall structure of the environmentally compatible ecological submerged dam of this invention can withstand sea state VI without significant damage or failure, and its wave dissipation and wave resistance performance achieves a wave height transmission coefficient of less than 0.45 and a wave energy transmission coefficient of less than 20%.

[0082] Module Name volume weight Longest side length Shortest side length D2-M1-5 1.3m³ 3.12t 1.60m 0.45m D2-M2-5 1.21m³ 2.90t 1.60m 0.45m D2-M3-5 1.24m³ 2.98t 1.60m 0.45m D2-M4-5 0.17m³ 0.42t 1.60m 0.15m D2-M5-5 0.34m³ 0.84t 1.60m 0.15m

[0083] Table 1

[0084] Traditional coastal engineering practices often employ marine breakwater structures that neglect their biological and ecological functions. Their surfaces are typically untreated, demolded concrete surfaces, and their smoothness hinders biological colonization and attachment. In fact, the structures themselves can obstruct water flow, impeding habitat restoration. This invention, however, incorporates a design that promotes ecosystem restoration and compatibility in the design of its ecological submerged dam and modular configuration. The design primarily uses concrete and prefabricated block structures, providing a concrete surface suitable for underwater installation of external anchoring and biocompatible attachments. The dam section possesses the following characteristics:

[0085] a. Provides abundant flat and three-dimensional surfaces for the colonization and addition of functional organisms, while reducing the hydrodynamic load on functional organisms in the early stages of attachment and reducing the probability of them falling off and dying due to extreme wave conditions.

[0086] b. Provide a certain surface topology to create turbulent boundary layer conditions, promote the mixed transport of nutrient particles and egg particles near the dam surface and increase the success rate of natural attachment and colonization;

[0087] c. Provide standardized accessory plug-in interfaces to enable the use of new biocompatible reef-based materials for external attachments to further enhance the biocompatibility of the dam body.

[0088] The basic unit module is prefabricated using reinforced concrete and cast with steel formwork, and threaded sleeves are provided on the surface as connector mating points. The specific materials used in this invention are as follows:

[0089] a. Marine engineering C40-P6 impermeable concrete combined with ordinary steel bars, with thickened steel bar protective layer, and HC steel sleeves are welded and embedded with steel bars, and integrally cast and demolded.

[0090] b. Composite reinforced concrete structures using ordinary C30 or C35 concrete combined with basalt BFRP composite reinforcement, employing stainless steel threaded sleeves to bind and embed the BFRP composite reinforcement, followed by integral casting and demolding.

[0091] c. A biocompatible reef base surface geometry with microporous and parallel microgroove structures is adopted. The microporous knots are 1-4 mm in diameter and 1-2 mm in depth, and the parallel microgroove structures are 2-5 mm wide and 1.5-3 mm deep. This increases the area of ​​the reef block available for attachment of reef-dwelling functional organisms, provides effective hiding space for attached larvae of reef-dwelling functional organisms, reduces the risk of them being eaten by other organisms, and provides interface micro-hydrodynamic induction conditions conducive to attachment of functional organism larvae, effectively improving the attachment rate of functional organism larvae.

[0092] The technical methods employed in the ecological reef base material of the submerged dam of this invention include, but are not limited to: dispersing a bioactive network system within a cement-based material using chemical and physical processes such as polymerization reactions, hydrogen bonding, charge interactions, and infiltration doping entanglement, forming marine ecological cement and ecological coating materials. The technical methods employed in the ecological accessories of the dam include, but are not limited to: materials that promote the attachment and growth of functional biological substrates; alkali-resistant and calcium carbonate deposition-induced microbial strain technology; highly efficient microbial immobilization and encapsulation technology; and polyacrylamide / chitosan surface-modified reef materials. This invention uses standardized plug-in interfaces for dam accessories, providing a structural basis for external attachments of ecological materials made from novel biocompatible reef base materials, and further enhancing the biocompatibility of the dam.

[0093] The basic unit module of this invention has pre-embedded M20 stainless steel threaded sleeves for transportation and hoisting, connector installation, and insertion of external accessories for ecological reef foundation materials. Therefore, M20 bolts can be used to directly fasten the external accessories of the ecological dam body material to the ecological submerged dam section. Based on this, the ecological dam body material accessories designed for the dam section are as follows: Figure 12 and Figure 13 As shown, both types have M20 bolt holes with countersunk holes in the center of the attachment. With the M20 bolts and self-locking washers, the actual connection with the dam section and dam body can be achieved.

[0094] The environmentally compatible ecological submerged dam construction area of ​​this invention is located in a remote island or reef with narrow reef flats or shallow reef slopes. In this area, the reef flat is not deep enough, and the working surface is narrow, making it difficult for large machinery and vessels to enter the site using conventional methods. This significantly increases the difficulty of underwater and surface operations. Therefore, when large engineering machinery cannot enter the site, the construction work in the reef area is mainly carried out by small, shallow-draft vessels (under 500 tons, with a full-load draft of less than 3.5m) and divers.

[0095] 1. Methods for construction vessel entry and reef deployment

[0096] The safe water depth of the reef section for environmentally compatible ecological submerged dam operations is 5-20m, and the width of the reef flat for construction vessels to anchor is 100-150m. For construction vessels with a maximum size of 50m in length, 8m in width, and 3m in draft, the safe entry of vessels into the site under the complex hydrodynamic conditions of the outer reef slope area is the primary issue to be addressed on this voyage.

[0097] Provided that the temporary underwater storage area on the reef should not be too far from the dam construction area, the specific steps are as follows:

[0098] a. Select an area with a low debris substrate or coral coverage of 8-12m near the reef section where the ecological submerged dam is to be used as a temporary underwater storage area for the reef.

[0099] b. Select two main anchor points approximately 100m in front of and behind the shoreline of the underwater temporary storage area; after the divers set up buoy markers, a small boat carries a 200-300kg main anchor and places it at the marked anchor point through a buoyancy bag, and then the divers carry the main cable to connect to the main anchor.

[0100] c. When the construction vessel sails to an area with a water depth greater than 30m offshore, the bow and stern are respectively attached to the main cable and the stern, and the vessel slowly enters the reef deployment area by means of cable traction through the double anchor points.

[0101] d. After the construction vessel enters the designated working position and the main cable is adjusted, in order to prevent the risk of the vessel drifting laterally and running aground or hitting a dam due to changes in wind and current direction or sudden waves, it is necessary to place two 50-100kg secondary anchors on the port and starboard sides of the vessel towards the shore and towards the sea respectively to help secure the vessel.

[0102] e. Under the coordinated command of the deck commander and the surface guide, the basic single-unit module of the deck reef is directly lifted into the underwater stacking area by the main crane of the construction vessel. After the basic single-unit module safely touches the bottom, the divers are responsible for untying the mooring line.

[0103] f. Without altering the underwater temporary storage area of ​​the basic single module, all anchorages do not need to be retrieved after daily operations are completed, but the floating cables on the water surface must be properly secured to prevent the vessel from moving or getting tangled in the propeller during navigation.

[0104] g. During the mother ship's relocation, mooring, and hoisting operations, at least two high-powered small boats should be on standby at the ship's side to assist the mother ship in adjusting its attitude and to prevent the risk of the mother ship running aground or hitting a dam if it fails to maneuver effectively in time in the event of a sudden change in sea conditions.

[0105] 2. Method for leveling the base

[0106] Considering the reef flat geomorphological characteristics of the area where the environmentally compatible ecological submerged bar reef section is located, and various constraints of on-site construction, with the premise of minimizing the impact of bar construction on the regional coral reef ecosystem, the specific steps of the base leveling operation are as follows:

[0107] a. Conduct a full-area relocation of reef-building corals from the dam construction area and auxiliary material placement area, and transfer the relocated corals to a temporary metal support frame.

[0108] b. Divers will conduct preliminary leveling work on the construction area, remove and lower large protruding coral reefs, and then quickly backfill the treated area into the low-lying area.

[0109] c. In multi-layer submerged dam structures, when the slope of the reef flat where the deep-water dam is located is large, a construction scheme using large foundation unit modules (such as the T-shaped main reef block in Mode 2) for edge protection should be adopted to replace the construction method of adjusting the slope using base pad modules in the foundation scheme. This will improve the overall stability of the dam body and reduce the actual amount of base pads used.

[0110] d. After completing the initial leveling work, cover the large rocks with environmentally friendly geotextile on the main dam body placement surface to reduce the loss of small fragments of rock during subsequent construction and dam service.

[0111] e. After the geotextile is laid, small pieces of stone are used to further level the surface on which the main dam body is placed, so that it achieves a flatness of 10mm-15mm / 2m for the placement and assembly of the dam foundation unit modules.

[0112] f. Finally, after the small stone slabs are leveled, base pads and reef blocks are laid on the base surface according to the design width, slope and total length of the main dam module. The number of base pads is adjusted according to the specific module surface conditions to meet the requirements for the placement of the main dam. The placement requirements are that the slope parallel to the coastline is no more than 1%-1.5% and the slope perpendicular to the coastline is no more than 0.3%-0.8%.

[0113] 3. Basic module transportation and dam assembly methods

[0114] Based on the functional design of the submerged dam, including wave dissipation indicators, low tide emergence, and modular deployment, changes in environmental conditions such as sea current intensity, direction, tide level, and wind direction can significantly impact the continuity of reef transport and dam assembly construction. Therefore, considering the inability of large engineering machinery to access the site and the aforementioned restrictive construction conditions, this invention adopts the following engineering solution:

[0115] a. The transfer of large dam unit modules and materials from the underwater temporary storage area to the construction dam section should be carried out using underwater semi-floating lifting with buoyancy bags or surface towing. That is, buoyancy bags and floats are used to lift the unit modules and materials off the base, so that they are suspended in the middle water layer or raised to the surface. Then, divers (underwater transfer) or small sampans (surface transfer) will transfer them to the construction area to reduce the impact of trampling and towing operations on the regional coral reef ecosystem during handling.

[0116] b. Navigation cables need to be laid from the underwater temporary storage area to the dam construction area to help divers identify directions in low visibility conditions and reduce the difficulty of manual towing in strong water flow conditions.

[0117] c. The dam foundation modules are assembled manually. When the water level between the placement surface and the water surface is greater than 2.5m, divers use buoyancy bags / buckets to lift the foundation modules to the designated positions. After underwater fine-tuning to ensure that the modules are properly connected, the buoyancy bags / buckets are vented to complete the placement of the foundation modules.

[0118] d. When the water level between the installation surface and the water surface is 2.5-1.5m, a floating raft platform is required for module transfer. This involves connecting the fixed lifting points on the module underwater to the lifting equipment on the floating raft platform using slings. The module is then lifted to a semi-submerged state, and the floating raft platform carries the foundation module to the installation location. The construction floating raft platform must be anchored at all four corners in the work area. Workers on the platform adjust the anchor cables at the four corners to move the floating raft platform to the designated work location, minimizing the impact on the surrounding ecosystem.

[0119] e. When using a floating raft platform for installation, the blocks to be assembled should be placed on both sides of the dam section in advance according to the construction sequence and sections when the water level is high. During installation, divers will connect and fix the floating platform slings to the reef blocks. After the workers on the raft lift the reef blocks to a semi-submerged state, they will be moved to the designated position. Divers will then assist in making minor adjustments to the position of the blocks to ensure accurate docking.

[0120] f. When the water level between the placement surface and the water surface is less than 1.5m, or when the water flow is too strong or the waves are too large to ensure the safety of the operation, the dam assembly operation should be stopped.

[0121] g. The ecological submersible dam assembly adopts a segmented construction approach, dividing the entire dam section into several segments, each no longer than 30m. After the reef blocks in each segment are assembled, divers install the subsequent fasteners and connectors to ensure that each assembled segment meets the design stability requirements. This prevents the dam body from shifting or collapsing due to insufficient structural strength in the event of unfavorable sea conditions that disrupt continuous construction.

[0122] This invention also incorporates reef-building functional organisms, primarily reef-building corals, including calcified coral algae and mollusks, as framework organisms for the coral reef ecosystem. The rapid replenishment of these resources facilitates the rapid habitat reconstruction and subsequent restoration of ecosystem services in environmentally compatible ecological submerged dams. This invention employs a bottom-seeding and colonization technique combining reef-building functional organisms, whereby these organisms are directly or after cultivation and colonized into suitable dam construction areas based on environmental suitability and spatial niche.

[0123] 1. Reef-building biological bottom seeding fixation method:

[0124] a. Cutting fixation method: In the main body of the submerged dam, the connecting area between dam bodies and the adjacent extended ecological restoration area, the cutting and bottom seeding is carried out on the substrate with suitable natural or artificial gaps. This technology is mainly used for the bottom seeding and planting of calcified coral algae blocks and transplanted branches.

[0125] b. Binding and Fixing Method: In areas where functional organisms need to be planted on the surface of the submerged dam body and connecting modules between dam sections, pre-embed or subsequently install structural components such as branch-shaped protrusions, T-shaped structures, or rings for binding and fixing the organisms. The components can be made of environmentally friendly materials such as stainless steel, cast iron, bioceramics, and basalt fiber. The functional organisms can be bound and fixed using environmentally friendly materials such as metal wire, metal buckles, and biodegradable strips. The specific binding and fixing method is tailored to the species, size, and shape of the organisms. This technology is suitable for the transplantation and bottom seeding of reef-building corals and calcified coral algae.

[0126] c. Adhesive Fixation Method: The adhesive method has low requirements on substrate type, structure, and the type and morphology of functional organisms. It is suitable for planting on other dam body substrates except for debris substrates in extended ecological restoration areas and is a widely used functional organism planting technology. Currently, adhesive materials suffer from problems such as high cost and difficulty in underwater operation. This invention uses an adhesive for planting reef-building functional organisms that combines operability and economy. It compares the operability, fixation effect, cost, and impact on the planting of reef-building functional organisms on concrete reef foundations with different adhesives. K600 type PI62.5 silicate cement and plastic steel putty (a two-component reactive curing polymer material) are suitable for underwater bonding and planting of reef-building functional organisms.

[0127] d. Modular fixing method: Based on the water depth, substrate structure, environmental suitability of functional organisms, and spatial ecological niche of the planting area, the single or multiple functional organisms to be planted are first combined and fixed on the basic module. After intermediate cultivation / in-situ acclimatization steps to allow the functional organisms to adapt to the habitat conditions of the planting area and reach the bottom seeding planting size and health status, they are planted together with the basic module on the submerged dam body, the connecting modules between dam bodies, and the hard substrate of the extended ecological restoration area. The overall planting module is fixed with adhesive or pre-embedded components (refer to the installation of ecological accessories for dam body). This method is applicable to the bottom seeding planting of all reef-building functional organisms. The material and structure of the basic module need to be adjusted according to the different functional organisms being planted. Reef-building corals and calcified algae generally use a flat square brick structure with no surface decoration, while reef-building shellfish generally use a three-dimensional block structure with an internal hollow structure. The basic module for planting reef-building corals and reef-building shellfish can be made of alkali cement or ceramic material, while the basic module for calcified algae can be made of alkali cement or environmentally friendly materials such as kaolin, alumina and calcium carbonate sintered at high temperature. High-temperature sintered materials can achieve higher porosity and pore size indicators (surface porosity 30%-50%, internal porosity >20%, pore size controlled in the range of 40~300 μm, preferably 100~200 μm), which is more suitable for the planting and growth of calcified algae.

[0128] 2. Reef-building biological environment suitability for colonization:

[0129] This invention utilizes single or multiple functional organisms for planting based on factors such as water depth, substrate structure, environmental suitability of functional organisms, and spatial ecological niche in the planting area to construct environmentally compatible ecological submerged dams.

[0130] For shallow reef flats and dams with shallow depths of less than 2 meters, strong hydrodynamic influences, hard coral reefs, and clastic substrates, as well as extended ecological restoration areas, a modular fixation method for calcified coral algae is adopted to carry out environmentally suitable planting. This accelerates the formation of benthic communities and rapidly improves primary productivity, while providing food sources and benthic environments for small reef-dwelling fish, invertebrates, and larvae of medium and large reef-dwelling fish.

[0131] For the connection areas between dam bodies and the extended ecological restoration areas of hard coral reefs and debris substrates without large structural components at a water depth of 4-8m, environmentally suitable combination planting methods were adopted, including modular fixing of calcified coral algae, cutting fixing, and fixing with reef-building coral adhesive. This was done to reconstruct the coral reef ecosystem in the non-submerged dam body area affected by construction, accelerate the bonding and solidification of the damaged substrate in this area, and improve the ecosystem recovery rate.

[0132] For the top area of ​​the submerged dam body (0-3m), where hydrodynamic forces are strong and water temperature and light intensity are high, this invention utilizes modular and adhesive fixing methods for bottom seeding of reef-building shellfish (oysters) to adapt to high temperatures and dry conditions, taking advantage of their resistance to heat and dew. This is combined with modular fixing methods for reef-building corals to achieve environmentally suitable combination planting. The reef-building coral species planted are mainly wave-resistant and heat-resistant clumping and crust-like corals (such as *Clerodendrum thomsoniae*, *Symplocos macranthum*, *Symplocos pubescens*, *Hymplocos hornedilum*, *Symplocos natans*, *Symplocos natans*, and *Symplocos natans*).

[0133] For the 3-5m deep submerged dam's central vertical section, where hydrodynamic effects are reduced, and considering the suitability of the biological environment for reef-building, this invention employs an adhesive fixation method for combined bottom seeding and planting of reef-building corals and calcified coral algae. The reef-building coral species planted are primarily wave-resistant and fast-growing types (such as warty cup corals, Ehrlich cup corals, pine-branched isoporosis corals, robust staghorn corals, strong staghorn corals, and multi-curved cup corals), while the calcified coral algae planted are mainly shell-like coral algae.

[0134] For the 3-5m horizontal elevation of the main body of the submerged bar and the 5-8m lower area of ​​the main body, based on the suitability of the reef-building biological environment and with the technical goal of rapid reconstruction of the ecological submerged bar ecosystem in an environmentally compatible manner, this invention employs adhesive fixation and modular fixation methods to carry out combined bottom seeding and planting of reef-building corals, combined with other reef-protecting organisms. The reef-building coral species planted are mainly branching, fast-growing corals (such as sharp staghorn coral, irregular branch staghorn coral, bulging staghorn coral, nose-shaped staghorn coral, granular staghorn coral, flat staghorn coral, columnar coral, and shallow cup-shaped perforated coral), while the calcified coral algae planted are mainly shell-shaped coral algae.

[0135] As an optional implementation, in some embodiments, the topographic information of the target area includes the planar contour information of the coral reef and the reef flat elevation variation information; the planar contour information of the coral reef includes the long axis direction information of the coral reef and the reef platform width information of the coral reef; the long axis direction information of the coral reef is measured by auxiliary equipment to determine the angle between the axis of the submerged barrier and the dominant wave direction; the reef platform width information of the coral reef is measured by auxiliary equipment, and a compactness index is obtained by combining the reef platform area, and the submerged barrier layout density is determined based on the compactness index; the reef flat elevation variation information includes the reef flat surface elevation information and the surrounding sea depth information; the reef flat surface elevation information and the surrounding sea depth information are measured by auxiliary equipment, and the relative height difference is calculated according to a preset formula to determine the submerged barrier reference surface.

[0136] Specifically, the long axis direction information of coral reefs is obtained through remote sensing image interpretation or UAV aerial surveying to extract the long axis azimuth of the coral reef's planar profile, which is used to determine the angle between the submerged bar axis and the dominant wave direction. The reef platform width information is obtained by measuring the maximum width (D_max) of the reef platform along its long axis direction. Combined with the reef platform area (S), a compactness index is calculated: CI = 4πS / D_max², used to classify reef platform types. For example, when CI > 0.8, it is considered compact; when CI < 0.5, it is considered dispersed. This index guides the density of submerged bar layouts; compact reef platforms need to be sparsely distributed to reduce ecological disturbance. The reef flat surface elevation information is obtained using a multibeam echo sounder combined with RTK-GPS positioning to acquire reef flat surface elevation data, generate a digital elevation model, and extract the reef flat top elevation (H_top) and the average water depth of the surrounding sea area (H_mean), calculating the relative elevation difference: ΔH = H_top - H_mean, used to determine the submerged bar reference level. When ΔH>2m, the reference surface of the submerged dam is taken as the top elevation of the reef flat to reduce the structural burial depth and construction costs; when 0.5m≤ΔH≤2m, the reference surface of the submerged dam is taken as the midpoint between the top elevation of the reef flat and the average water depth of the surrounding sea area to balance the wave-cutting effect and structural stability; when ΔH<0.5m, the reference surface of the submerged dam needs to be 0.3~0.5m lower than the top of the reef flat to avoid the submerged dam being exposed and causing local scouring.

[0137] As an optional implementation, in some embodiments, the hydrodynamic information of the target area includes flow characteristic information, wave characteristic information, and tidal characteristic information; the flow characteristic information includes flow velocity and direction information and flow type information; the flow velocity and direction information is monitored by auxiliary equipment to obtain average flow velocity information, maximum flow velocity information, and flow direction distribution information, and the slope of the submerged dam is determined based on the obtained average flow velocity information, maximum flow velocity information, and flow direction distribution information; the flow type information is monitored by auxiliary equipment to obtain tidal current information, residual current information, and wave-induced flow information, and the location of the submerged dam is determined through simulation experiments based on the obtained tidal current information, residual current information, and wave-induced flow information; the wave characteristic information includes wave element information and wave type information; the wave element information is monitored by auxiliary equipment to obtain effective wave height information, wave period information, and wave direction information, and the dam height of the submerged dam is determined based on the obtained effective wave height information, wave period information, and wave direction information; the wave type information is monitored by auxiliary equipment... Monitoring yields information on wind and wave, swell, and mixed waves. Based on this information, simulation experiments are used to determine the wave-facing structure of the submerged dam. Tidal characteristic information includes tidal type, tidal level parameters, and tidal range. Tidal type information is obtained from historical records for semi-diurnal and diurnal tides. Based on this information, simulation experiments are used to determine the weight of the submerged dam. Tidal level parameters are monitored using auxiliary equipment to obtain information on the highest, lowest, and average tide levels. Based on the highest tide level, simulation experiments are used to determine the top elevation of the submerged dam. Based on the lowest tide level, simulation experiments are used to determine the burial depth of the submerged dam. Based on the average tide level, simulation experiments are used to determine the centerline elevation of the submerged dam. Tidal range information is obtained from historical records for spring tide and neap tide ranges. Based on this information, simulation experiments are used to determine the local structure of the submerged dam.

[0138] Specifically, a combination of long-term monitoring and numerical simulation is used to obtain the regional average flow velocity. Multiple flow monitoring stations are set up in the target area, and high-precision velocity measurement instruments, such as the Acoustic Doppler Current Profiler (ADCP), are used for long-term continuous monitoring, recording flow velocity data at different times and locations. Simultaneously, numerical simulation software, such as MIKE21 and TELEMAC, is used to build a numerical model of the flow in the target area. Relevant topographic and boundary conditions are input to simulate regional flow motion and obtain the average velocity distribution. Through comprehensive analysis of the monitoring data and simulation results, the regional average flow velocity is determined. This data directly affects the scour resistance design of submerged dams; for example, the dam slope and foundation reinforcement methods are determined based on the average flow velocity. During extreme events, such as typhoons and storm surges, monitoring of the flow velocity in the target area is strengthened. Using real-time monitoring data, combined with historical extreme event data and numerical simulation methods, the instantaneous flow velocity under extreme events is analyzed. Maximum flow velocity is used as a check condition for the structural strength of submerged dams. During the design process, it is ensured that the dam body has sufficient anti-sliding and anti-overturning stability to withstand the impact of extreme flow velocities. Flow direction data is obtained through flow monitoring stations, and the angle between the primary and secondary flow directions is analyzed. The orientation of the submerged dam is determined based on the flow direction distribution characteristics. Generally, the orientation of the submerged dam is perpendicular or oblique to the main flow direction to maximize energy dissipation. For example, when the main flow direction is relatively clear, arranging the submerged dam perpendicular to the main flow direction can effectively block the flow and reduce the erosion of the coastline. When there are multiple flow directions, an oblique arrangement can be adopted according to the angle between the primary and secondary flow directions, so that the submerged dam can play a good protective role under the action of flow from different directions.

[0139] Based on the tidal type of the target area, such as semi-diurnal or diurnal tides, analyze the characteristics of the reciprocating currents caused by tidal currents. Determine the temporal variation patterns of tidal velocity and direction through long-term tidal observation and numerical simulation. Consider the blocking effect of submerged dams on tidal currents, such as analyzing the extent and intensity of the backflow zone after dam construction. The existence of the backflow zone may affect the hydrodynamic environment and sediment transport of the surrounding sea area; therefore, the extent of the backflow zone must be reasonably controlled during submerged dam design to avoid adverse impacts on the coral reef ecosystem. Residual currents are long-term average flows caused by wind, density differences, etc. Analyze the velocity, direction, and distribution characteristics of residual currents through long-term flow monitoring and numerical simulation. Residual currents can affect the long-term stability of submerged dams, for example, potentially leading to scouring or siltation at the dam bottom. Based on the characteristics of residual currents, take appropriate protective measures in the submerged dam foundation design, such as installing bottom protection structures in areas prone to scouring and considering appropriate drainage facilities in areas prone to siltation. Wave breaking generates nearshore currents, such as coastal currents and fracture currents. Using wave observation data and numerical simulation methods, the velocity, direction, and distribution characteristics of wave-induced flows are analyzed. The impact of wave-induced flows on the local hydrodynamic conditions of submerged dams is assessed, including potential increases in local flow velocity and changes in flow direction. In the design of submerged dams, optimizations are made to the local structures to address the effects of wave-induced flows, such as increasing the strength and stability of local structures.

[0140] Significant wave height information refers to the average wave height within a statistical period, reflecting the wave energy intensity of the region. Wave data for the target area is acquired through wave observation buoys, satellite remote sensing, and other methods, and the significant wave height is obtained through statistical analysis. Significant wave height directly affects the wave dissipation design of submerged dams. When designing submerged dams, the dam height must be higher than the design wave height to ensure that the dam can effectively weaken wave energy and reduce wave impact on the coastline. Wave period information refers to the time interval between wave crests. Long-period waves, such as typhoon waves, have greater energy and impact force, resulting in stronger destructive effects on submerged dams. Wave observation and numerical simulation are used to determine the wave period distribution of different wave types in the target area. For long-period waves, the structural stiffness of the submerged dam needs to be strengthened, for example, by increasing the strength of the dam material and optimizing the dam structure, to improve the submerged dam's ability to resist the impact of long-period waves. Wave direction information refers to the angle between the wave propagation direction and the coastline. Wave observation and numerical simulation are used to analyze the distribution characteristics of wave direction. Wave direction determines the design of the wave-facing side of the submerged dam; for example, using a sloping dam can disperse wave energy and reduce the direct impact of waves on the dam body. Based on the wave direction characteristics, the shape and slope of the wave-facing surface of the submerged dam should be designed reasonably so that the submerged dam can play a good wave-dissipating effect under the action of waves in different wave directions.

[0141] Wind waves are short-period waves generated by local wind fields. The dominant direction and frequency of wind waves are analyzed using wind rose diagrams. Wind rose diagrams visually show the frequency and speed of winds from different directions, allowing for the determination of the main source direction and frequency of wind waves. In submerged dam design, the wave-facing surface design is optimized based on the dominant direction of wind waves to improve the dam's energy dissipation effect. Swells are long-period waves that propagate from the open sea to islands and reefs, possessing concentrated energy and strong destructive power. The wave height, period, and propagation direction of swells are analyzed in detail. Swells place high demands on the submerged dam's ability to withstand wave overtopping; therefore, the stability of the submerged dam under the action of swells must be checked during dam design to ensure that the dam will not be washed away or overtaken. For example, increasing the height of the submerged dam and strengthening the stability of the dam crest structure can be employed. Mixed waves are complex wave fields resulting from the superposition of wind waves and swells. The combined effects of mixed waves are analyzed through numerical simulations (such as the SWAN model) or physical model experiments. The SWAN model is a widely used software for wave numerical simulation, capable of simulating complex wave fields involving wind waves, swells, and their interactions. Physical model tests, on the other hand, simulate actual ocean wave conditions in a laboratory setting, allowing for a direct observation of the effects of mixed waves on submerged dams. Based on the results of numerical simulations and physical model tests, the structural design of submerged dams can be optimized, improving their adaptability and stability under mixed wave conditions.

[0142] Semi-diurnal tides occur twice daily, with high and low tides, as seen in parts of the South China Sea. In semi-diurnal areas, submerged dams must withstand frequent submersion-exposure cycles. The materials used for these dams must be highly durable and able to resist long-term seawater erosion and alternating wet and dry conditions. For example, corrosion-resistant concrete or metal materials with good protective coatings are suitable. Diurnal tides occur once daily, with high and low tides, as seen in parts of the northern Indian Ocean. The tidal range in diurnal areas can be larger, requiring careful verification of the submerged dam's buoyancy stability. In the foundation design, measures such as increasing foundation weight and installing anti-buoyancy anchors are taken to ensure that the submerged dam will not float or become unstable due to buoyancy under large tidal ranges.

[0143] The highest tide level determines the crest elevation of the submerged dam. When designing the crest elevation, it must be higher than the design high tide level plus the safety freeboard. The safety freeboard is determined based on factors such as the importance of the target area and wave conditions, and is generally between 0.5 and 1.5 meters. The lowest tide level affects the exposed area of ​​the submerged dam foundation. When designing the foundation, bottom scour protection must be considered. The burial depth of the foundation is determined based on the design low tide level, and bottom protection structures, such as riprap or concrete bottom protection, are installed around the foundation to prevent seawater from scouring the foundation at low tide and affecting the stability of the submerged dam. The mean tide level is used for the design of the submerged dam's reference surface. For example, when determining the elevation of the dam's centerline, the mean tide level is used as a reference benchmark to ensure that the submerged dam maintains a reasonable structural form and hydrodynamic performance under different tidal conditions.

[0144] The spring tide range refers to the maximum tidal range during the synodic month, reflecting the intensity of regional tidal energy. The stress on the submerged dam is comprehensively assessed in conjunction with wave conditions. During the spring tide range, seawater flows faster, and wave energy is also greater, resulting in a stronger force on the submerged dam. When designing the submerged dam, the combined effects of the spring tide range and waves must be considered to strengthen the structural strength and stability of the dam, ensuring its safe and stable operation under the combined influence of spring tides and waves. The neap tide range refers to the minimum tidal range between the first and last quarter moons, which may affect the local hydrodynamic environment of the submerged dam. For example, while the change in water flow velocity is relatively small during the neap tide range, it may create special flow conditions in certain local areas, such as eddies. Analyzing the impact of the neap tide range on the local hydrodynamic environment of the submerged dam allows for optimization of local structures in the dam design, preventing damage or instability due to changes in local flow conditions.

[0145] As an optional implementation, in some embodiments, the ecological information of the target area includes coral species and distribution information and coral reef health status information; the coral species and distribution information includes coral type information, coral coverage information, and coral growth rate information; the coral type information is monitored by auxiliary equipment to obtain reef-building coral compatibility information or soft coral compatibility information; the coral coverage information is monitored by auxiliary equipment to obtain high coverage area information and low coverage area information; the coral growth rate information is monitored by auxiliary equipment to obtain fast-growing coral information and slow-growing coral information; the coral reef health status information is monitored by auxiliary equipment to obtain bleaching risk area information and disease damage area information; based on the obtained reef-building coral compatibility information or soft coral compatibility information, high coverage area information, low coverage area information, fast-growing coral information, slow-growing coral information, bleaching risk area information, and disease damage area information, the material of the dam is determined through simulation experiments and the construction of physical models.

[0146] Specifically, the material selection for the reef-building coral adaptation information is calcareous biomimetic concrete with a CaCO3 content ≥60% and a porosity of 25-30%. The structural form adopts a branching structure similar to staghorn coral, with a branching angle of 60° and a branch diameter of 8-12mm. The surface treatment uses laser-engraved microgrooves to simulate the topology of natural reefs, with a groove width of 0.5mm and a depth of 1.0mm. The material selection for the soft coral adaptation information is diatomaceous earth composite material with a SiO2 content ≥70% and an elastic modulus of 0.8-1.2Gpa. The structural form adopts a honeycomb porous structure to provide space for soft coral attachment, with a pore size of 3-5mm. The surface treatment uses plasma treatment to create a superhydrophilic surface with a contact angle <10°.

[0147] When the coverage rate is greater than 50%, it is a high coverage area. Translucent concrete is used to reduce light shading, and its light transmittance is ≥30%. At the same time, a flow channel is set up to maintain water flow exchange. The channel is 20cm wide and 15cm deep. When the coverage rate is less than 20%, it is a low coverage area. Coral cultivation units with a volume of 50L are embedded, filled with calcareous sand, and the surface is coated with a biological inducer containing 150ppm of calcium coralate.

[0148] As an optional implementation, in some embodiments, numerical simulation analysis includes the following steps: inputting the acquired topographic information of the target area into computer software, simulating the response of submerged dams of different structural forms under the topographic conditions and hydrodynamic effects of the target area, and obtaining simulation results; comparing different simulation results with preset results, and selecting the simulation result that best matches the preset results as the submerged dam structural information. The computer software can be either MIKE series software or FLOW-3D software. MIKE series software (such as MIKE21 / MIKE3): based on the finite difference method / finite volume method, excels at two-dimensional / three-dimensional hydrodynamic-sediment-wave coupling simulation. For example, MIKE21 can simulate the tidal field, wave propagation deformation, and sediment transport path around the submerged dam, accurately depicting the complex coastline and seabed topographic undulations of islands and reefs through topographic meshes. After inputting measured topographic data, it can quantitatively analyze the influence of different submerged dam structures on water flow velocity, wave breaking location, and vortex structure. FLOW-3D: based on the VOF method to capture free surfaces, excels at simulating local complex flow details. Its porous media model can simulate the pore hydrodynamic characteristics of permeable submerged dams, and combined with topographic data, it can evaluate the impact of different porosities and dam shapes on wave dissipation and local scour.

[0149] As an optional implementation method, in some embodiments, the physical model test includes the following steps: fabricating a submersible dam model according to a preset scale based on the topographic information of the target area; placing the submersible dam model in a laboratory water tank or wave pool for testing to simulate hydrodynamic conditions and obtain simulation results; comparing different simulation results with preset results and selecting the simulation result that best matches the preset results as the submersible dam structural information. The scale selection can be based on similarity criteria, such as Froude number similarity or Reynolds number similarity, to determine the geometric scale and ensure that the hydrodynamic characteristics of the model and the prototype satisfy a similarity relationship. For example, the island / reef topographic model needs to be constructed using high-precision 3D printing or plaster / resin casting to accurately replicate micro-topographic features such as reefs and shoals. Material selection can use plexiglass, aluminum alloy, or foam materials, ensuring that the density and stiffness are similar to the prototype materials; the bottom of the water tank / pool is laid with sandy / rocky substrate to simulate the real seabed. Hydrodynamic condition simulation can be achieved by generating regular or irregular waves using a wave generator and simulating tidal currents using a circulating water tank or pump system. For example, in a wave pool, a multi-directional wave generation system can be set up to simulate complex wave conditions such as oblique waves and breaking waves. Measurement methods can include using an acoustic Doppler current meter (ADV) to measure the velocity profile, a laser wave meter to record wave height and period, particle image velocimetry (PIV) to capture the vortex structure around the dam, and settlement plates or sonar scanning to monitor changes in sediment erosion and deposition.

[0150] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0151] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, characterized in that, Includes the following steps: The topographic, hydrodynamic and ecological information of the target area was obtained respectively, and the structural, depth and material information of the submerged dam were determined through numerical simulation analysis and physical model test. Based on the submerged dam structure information, the submerged dam depth information, and the submerged dam material information, a submerged dam is constructed within the target area.

2. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 1, is characterized in that... The topographic information of the target area includes the planar outline information of coral islands and reefs and the elevation change information of reef flats; The planar contour information of the coral reef includes the long axis direction information of the coral reef and the width information of the reef platform. The long axis direction information of the coral reef is measured by auxiliary equipment to determine the angle between the submerged bar axis and the dominant wave direction; The width of the reef platform of the coral islands and reefs is measured by auxiliary equipment, and the compactness index is obtained by combining the reef platform area. The density of the submerged bar layout is determined based on the compactness index. The reef flat elevation change information includes reef flat surface elevation information and surrounding sea area water depth information; The elevation information of the reef flat surface and the water depth information of the surrounding sea area are measured by auxiliary equipment, and the relative height difference is calculated according to a preset formula to determine the reference surface of the submerged dam.

3. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 1, is characterized in that... The hydrodynamic information of the target area includes flow characteristics, wave characteristics, and tidal characteristics. The water flow characteristic information includes flow velocity and flow direction information and water flow type information; The flow velocity and flow direction information are monitored by auxiliary equipment to obtain average flow velocity information, maximum flow velocity information and flow direction distribution information. The slope of the submerged dam is determined based on the obtained average flow velocity information, maximum flow velocity information and flow direction distribution information. The water flow type information is monitored by auxiliary equipment to obtain tidal flow information, residual flow information and wave-induced flow information. Based on the obtained tidal flow information, residual flow information and wave-induced flow information, the location of the submerged dam is determined through simulation experiments. The wave characteristic information includes wave element information and wave type information; The wave element information is monitored by auxiliary equipment to obtain effective wave height, wave period and wave direction information. The dam height of the submerged dam is determined based on the obtained effective wave height, wave period and wave direction information. The wave type information is obtained by monitoring wind wave information, swell information and mixed wave information through auxiliary equipment. Based on the obtained wind wave information, swell information and mixed wave information, the wave-facing structure of the submerged dam is determined through simulation experiments. The tidal characteristic information includes tidal type information, tidal level parameter information, and tidal range information; The tidal type information is obtained by acquiring semi-diurnal and diurnal tidal information from historical records. The weight of the submerged dam is determined by simulation experiments based on the acquired semi-diurnal and diurnal tidal information. The tidal level parameter information is monitored and obtained through auxiliary equipment, including the highest tide level, the lowest tide level, and the average tide level. The top elevation of the submerged dam is determined through simulation experiments based on the highest tide level information, the burial depth of the submerged dam is determined through simulation experiments based on the lowest tide level information, and the centerline elevation of the submerged dam is determined through simulation experiments based on the average tide level information. The tidal range information is obtained through historical records of spring tide and neap tide, and the local structure of the submerged dam is determined through simulation experiments based on the obtained spring tide and neap tide information.

4. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 1, is characterized in that... The ecological information of the target area includes information on coral species and distribution, and information on the health status of coral reefs; The coral species and distribution information includes coral type information, coral coverage information, and coral growth rate information; The coral type information is monitored and obtained through auxiliary equipment to acquire reef-building coral adaptation information or soft coral adaptation information; The coral coverage information is monitored and high-coverage area information and low-coverage area information are obtained through auxiliary equipment; The coral growth rate information is monitored and acquired through auxiliary equipment, including information on fast-growing corals and slow-growing corals. The coral reef health status information is monitored and acquired through auxiliary equipment, including information on bleaching risk areas and disease / damage areas. Based on the obtained information on reef-building coral compatibility or soft coral compatibility, high coverage area information, low coverage area information, fast-growing coral information, slow-growing coral information, bleaching risk area information, and disease and damage area information, the material of the dam body is determined through simulation experiments and the construction of physical models.

5. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 1, is characterized in that... The numerical simulation analysis includes the following steps: The topographic information of the target area is input into computer software to simulate the response of submerged dams of different structural forms under the topographic conditions and hydrodynamic action of the target area, and the simulation results are obtained. Different simulation results are compared with preset results, and the simulation result that best matches the preset results is selected as the submerged dam structure information.

6. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 1, is characterized in that... The physical model experiment includes the following steps: A submerged dam model is created according to a preset scale based on the terrain information of the target area. The submerged dam model was placed in a laboratory water tank or wave pool for testing to simulate hydrodynamic conditions and obtain simulation results. Different simulation results are compared with preset results, and the simulation result that best matches the preset results is selected as the submerged dam structure information.

7. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 1, is characterized in that... After constructing a submerged dam within the target area, based on the obtained topographic and ecological information, reef-building organisms are planted at the bottom of the submerged dam. Planting methods include cutting fixation, binding fixation, adhesive fixation, or modular fixation. Cutting and fixing method: In the main body of the submerged dam, the connection area between dam bodies and the adjacent extended ecological restoration area, the substrate with natural or artificial gaps is embedded and sown. Binding and fixing method: Functional biological binding and planting is carried out on the surface of the submerged dam body and the connecting modules between the dam bodies. The planting area is pre-embedded or installed with branch-shaped protrusions, T-shaped or ring-shaped structural components that can be used for binding of functional biological components to meet the requirements of biological binding and fixing. The structural components are made of one of stainless steel, cast iron, bioceramics or basalt fiber. The functional biological components are made of one of metal wire, metal buckle or biodegradable strip. Adhesive fixing method: Sowing and planting are carried out on the other parts of the dam body except for the debris base in the extended ecological restoration area; Modular fixing method: Based on the water depth, substrate structure, environmental suitability of functional organisms and spatial ecological niche of the planting area, the single or multiple functional organisms to be planted are first combined and fixed on the basic module. After intermediate cultivation or in-situ acclimatization steps to allow the functional organisms to adapt to the habitat conditions of the planting area and reach the size and health status for bottom seeding, they are planted together with the basic module on the submerged dam body, the connecting modules between dam bodies and the hard substrate of the extended ecological restoration area. The overall planting module is fixed with adhesive or pre-embedded components.

8. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 7, is characterized in that... After constructing a submerged dam within the target area, based on the obtained hydrodynamic information, a combination of single or multiple functional organisms is used for planting to construct an environmentally compatible ecological submerged dam. When targeting the connection zone between shallow reef flats and dams with strong dynamic effects in shallow water (less than 2m), hard coral reef rocks, and clastic substrates, as well as the extended ecological restoration area, a modular fixation method for calcified coral algae is adopted to carry out environmentally suitable planting. When targeting the connection area between dams and the extended ecological restoration area of ​​hard coral reefs and debris bottoms without large structural components at a water depth of 4-8m, environmentally suitable combination planting methods are adopted, including modular fixing method of calcified coral algae, cutting fixing method, and fixing method of reef-building coral adhesive. When targeting the top area of ​​the submerged dam body in the 0-3m range, the modular fixing method and adhesive fixing method are used to carry out bottom seeding and planting of reef-building shellfish, and the modular fixing method of reef-building corals is combined with environmentally suitable combination planting. When targeting the vertical facade area in the middle of the submerged dam body of 3-5m, the adhesive fixing method is used to carry out combined bottom seeding and planting of reef-building corals and calcified coral algae. When targeting the horizontal elevation of the middle section of the submerged dam body (3-5m) and the lower section of the submerged dam body (5-8m), a combination of adhesive fixing and modular fixing methods is used for bottom seeding and planting, primarily using reef-building corals and combined with other reef-building and protective organisms.

9. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 1, is characterized in that... The submerged dam is formed by splicing together several modules of different shapes. The modules of different shapes are prefabricated using reinforced concrete material and cast with steel formwork. The surfaces of the modules of different shapes are provided with threaded sleeves. The modules of different shapes include Z-shaped modules, L-shaped modules, T-shaped modules, flat modules, pointed modules, cuboid modules and hexahedral modules. The cuboid module is provided with trapezoidal mating teeth, the hexahedral module has a mating interface on its side, and the upper surface of the hexahedral module is provided with a mating ring, and the mating interface is adapted to the mating ring.

10. The method for constructing an environmentally compatible ecological submerged dam suitable for coastal protection of coral islands and reefs in the open sea, as described in claim 8, is characterized in that... Several modules of different shapes have microporous structures and parallel microgroove structures to form a biocompatible reef base surface geometry; The microporous structure has a pore diameter of 1-4 mm and a pore depth of 1-2 mm; the parallel microgroove structure has a groove width of 2-5 mm and a groove depth of 1.5-3 mm.

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