Ecological landscape type disaster reduction seawall and design method thereof

Abstract

The invention relates to an ecological landscape type disaster reduction seawall, the section form of the seawall is a gentle slope into-sea multi-stage composite type, and the seawall structurally comprises a seawall foot on the seaside, a first-stage planting platform, a gentle slope, a second-stage planting platform, a waterside platform, a wave wall and a road which are sequentially arranged from sea to land; on the basis of ensuring safety, the seawall is subjected to ecological landscape design, so that the seawall can play roles in intercepting silt and purifying water; the effects of weakening wave energy and reducing marine disaster threats can be achieved; and meanwhile, the hydrophilicity of the seawall can be improved, and a leisure activity space is provided for people. The invention further relates to a design method of the ecological landscape type disaster reduction seawall and a method for determining the crest elevation of the ecological landscape type disaster reduction seawall. The section form of the seawall can be determined according to the wave height and the height difference between the sea level and the road surface, the crest elevation of the seawall can be effectively reduced, the engineering cost is reduced, and the seawall ecological function is increased.

Description

Technical Field

[0001] The invention relates to the technical field of seawall section design, and in particular to an ecological landscape type disaster reduction seawall and a design method thereof. Background Art

[0002] The main function of seawalls is to reduce the damage caused by storm surges (floods) and waves, and effectively improve the disaster prevention and mitigation capabilities of coastal cities. Traditional seawalls generally use structures such as mortar-laid blocks and cast-in-place concrete. The submarine plants installed during the construction of seawalls are often only to maintain the surrounding ecological environment and to ensure the ecological landscape around the coast as much as possible, without considering the use of plants to eliminate waves. Therefore, traditional seawalls not only reduce the original coastline's tidal absorption function, but also block the exchange of materials and energy between the sea and the land, and weaken the self-purification capacity of the water bodies along the line. At the same time, it hinders the contact between people and the ocean, and destroys the ecological, landscape and other valuable functions of the coast to a certain extent.

[0003] Chinese patent CN215165216U (publication date: May 24, 2021) discloses a new type of wave-type ecological seawall based on a slope structure. The structure of the new type of wave-type ecological seawall is, from bottom to top, a natural riprap revetment, a primary slope covered with wave-breaking blocks, an arc-shaped sightseeing platform with a plank road, a groove that transitions between the upper and lower slopes and has a drainage function, a wavy secondary slope covered with a variety of plants to meet the ornamental function, and a top platform planted with various vegetation to form a wetland park. Traditional seawalls destroy the original natural landscape and flora and fauna of the coast, and are poor in ecology, hydrophilicity and aesthetics. This utility model designs a new type of ecological seawall with a wave-type slope structure based on the traditional sloped seawall, which can meet all of the above requirements at the same time through innovative design.

[0004] Chinese patent CN117926756A (publication date: March 12, 2024) discloses a green and vibrant ecological seawall system for eroded coasts, including an ecological seawall main body, artificial oyster reefs, groins, vegetation protection belts, wave-breaking submerged dikes, artificial fish reefs and seaweed beds, and the ecological seawall main body, artificial oyster reefs, groins, vegetation protection belts, wave-breaking submerged dikes, artificial fish reefs and seaweed beds are arranged in sequence from land to sea; the ecological seawall main body adopts a duplex structure and is constructed with multi-level hydrophilic platforms; the artificial oyster reefs are arranged at the foot of the seawall; the groins are arranged at the foot of the seawall; the wave-breaking submerged dikes and artificial fish reefs form a weak siltation environment in front of the dike. This invention can weaken the erosive effect of coastal currents on the coast by arranging the spur dike at the foot of the seawall; it can promote wave breaking, reduce wave energy, and form a weak siltation environment in front of the dike by combining the wave-breaking submerged dike and artificial fish reef; and it can intercept silt and weaken wave energy by arranging the vegetation protection belt in the area between the submerged dike and the seawall and planting native coastal salt marsh vegetation.

[0005] Chinese patent CN117966662A (publication date: March 19, 2024) discloses an ecological seawall structure for marine ecological restoration, including a seawall main body, a water-facing slope and a submerged dike, the water-facing slope is arranged on one side of the seawall main body, the submerged dike is arranged on the side of the water-facing slope away from the seawall main body, a planting trough is provided on the seawall main body, a collecting port is provided on the water-facing slope, the collecting port extends to the inside of the seawall main body, a mounting shaft is movably installed at a position near the outside of the collecting port, a movable plate is fixedly sleeved on the mounting shaft, a reset telescopic rod is fixedly installed at the position of the movable plate in the collecting port, a group of drainage holes are provided on the movable plate, and a protective mechanism and an irrigation mechanism are provided on the seawall main body; the present invention achieves the effect of blocking seawater at high tide, avoiding the situation where seawater submerges saline-alkali plants and causes plant death, and solves the problem that seawater easily submerges saline-alkali plants and causes plant death at high tide.

[0006] Based on the above search and the existing technology, it is found that the current relevant patents focus on increasing ecological protection to improve the seawall ecosystem, and do not propose a solution to wave cutting and disaster reduction from the seawall cross-section structure, nor do they have a systematic design method. Summary of the invention

[0007] In order to solve the above technical problems, the first purpose of the present invention is to provide an ecological landscape type disaster reduction seawall, which can purify water, eliminate waves and reduce disasters, and at the same time improve the hydrophilicity of the coast; the second purpose of the present invention is to provide a design method for an ecological landscape type disaster reduction seawall; the third purpose of the present invention is to provide a method for determining the crest elevation of an ecological landscape type disaster reduction seawall. It can synergistically eliminate waves, and has the characteristics of beauty, economy, and safety. It can make the coast beautiful at low cost and high efficiency while reducing the threat of marine disasters. The crest elevation can be determined and reduced according to the wave elimination effect of seawall plants, reducing the amount of engineering and costs, and determining the height and width of the seawall according to different waves and tide conditions to maximize economic benefits.

[0008] An ecological landscape disaster reduction seawall, the cross-section of which is a multi-level composite type with a gentle slope into the sea, including a planting belt, a seawall structure, dump stones and original soil; The dumping stones cover the upper part of the original soil; The seawall structure covers the upper part of the fill stone.

[0009] The seawall structure includes a footing on the sea side of the seawall, a primary planting platform, a gentle slope, a secondary planting platform, a hydrophilic platform, a wave-breaking wall, and a road, which are arranged in sequence from sea to land.

[0010] The seawall structure is composed of the seawall underwater area, water level change area, water area and seaward side from the sea to the land; The underwater area of ​​the seawall is located below the tide level on the sea side, including the foot of the seawall and the first-level gentle slope on the sea side; The water level fluctuation area is located above the sea side tide level and below the average tide level, and includes a first-level planting platform and a second-level gentle slope; The above-water area is located above the average tide level and is considered as the land area, including the secondary planting platform, the tertiary gentle slope, the hydrophilic platform and the wave-breaking wall; The seaward side, located behind the wave-breaking wall, includes a road for pedestrians and vehicles to pass through.

[0011] Preferably, the dumping stone is mainly composed of crushed stone, sand and clay, and is formed by artificial backfill; the diameter of the crushed stone is 5.0 to 35.0 cm, and the sand and clay are filling materials, and the drainage performance is good.

[0012] Preferably, the embankment foot adopts a structure with multiple gaps and a rough surface; Preferably, the structure of the road is, from top to bottom, a road surface, a sea-facing side protection surface, and a block stone permeable prism; Preferably, the first-level gentle slope, the first-level planting platform and the second-level gentle slope are located below 0.3 m above the average tide level, and adopt a multi-void, rough-surfaced structural type, and dry masonry stones, crushed stones and anti-filtration non-woven fabrics are arranged in sequence from top to bottom; Preferably, the secondary planting platform, the hydrophilic platform and the seaward side protection surface adopt a multi-void and rough surface structure, and dry masonry blocks and crushed stones are arranged in sequence from top to bottom; Preferably, the three-level gentle slope connects the secondary planting platform and the hydrophilic platform, and the slope of the three-level gentle slope is less than or equal to 1:3. Block stone permeable prisms and dry-laid blocks are arranged in sequence from top to bottom without considering the porosity of the dry-laid blocks, so as to facilitate a small amount of overtopping waves to enter the soil below through the gaps between the blocks, thereby reducing water accumulation on the hydrophilic platform.

[0013] Preferably, exhaust holes are arranged inside the permeable prism of the block stone.

[0014] Preferably, a row of gabion box structures are arranged on the primary planting platform, in which blocks of stone and planting soil are backfilled, and a primary planting belt is planted in the soil; Preferably, a reinforced Mac mat and planting soil are arranged on the secondary planting platform, and a secondary planting belt is planted in the soil; Preferably, the plant types of the primary planting belt include reeds and Suaeda salsa, and the plant types of the secondary planting belt include Hibiscus sylvestris and Tamarix chinensis; Preferably, the total width of the planting belt is selected from 25m-400m, and the width of the planting belt is arranged in a decreasing order. The first-level planting belt has the largest width, and the widths of the subsequent-level planting belts decrease successively. The width of the first-level planting belt does not exceed twice the width of the second-level planting belt, and so on.

[0015] Preferably, the elevation of the hydrophilic platform is the elevation of the top of the embankment; Preferably, the dike top elevation is determined by the planting density, width and plant species of the primary planting belt in the water level fluctuation area and the secondary planting belt in the water area. The larger the planting density N, the larger the planting width L, and the larger the plant diameter D, the smaller the wave climbing height R will attenuate after passing through the green plant area, so that the required dike top elevation Z p Reduce.

[0016] A design method for an ecological landscape type disaster reduction seawall comprises the following steps: Step S1, determining the seawall area, filling the landfill on the original soil foundation, and laying the anti-filtration non-woven fabric on the original soil and the landfill; Step S2, arranging crushed stones on the reverse filter nonwoven fabric and then laying dry masonry stones; Step S3, a gabion box is placed on the upper part of the dry block stone platform in the water level change area, and then filled with stones and backfilled with planting soil. The thickness of the planting soil does not exceed the gabion box, and a primary planting belt is planted in the gabion box; Step S4: The water level change area is a salt marsh-like ecological environment, and the target plants are determined in the first-level planting belt according to the natural geographical conditions of the project area; Step S5: a reinforced Mac mat is laid on the upper part of the dry block stone platform in the water area, and planting soil is backfilled, and a secondary planting belt is set in the planting soil. The reinforced Mac mat creates conditions for water flow, realizes the natural exchange of water and soil, and is convenient for planting small trees that can grow in coastal saline-alkali land; Step S6: The water area planting platform is connected to the hydrophilic platform on a slope, and a permeable stone prism is placed. Dry stone blocks are laid underneath to facilitate a small amount of overtopping waves to enter the soil below through the gaps between the stones, thereby reducing water accumulation on the hydrophilic platform; Step S7: a hydrophilic platform is set up in the water area for pedestrians to walk and enjoy the scenery. Pedestrians are not recommended to enter during extreme high tides. Step S8: Considering the extreme high tide level, a wave-breaking wall is set on the top of the dike, and its elevation is determined by referring to the wave height after the wave-breaking effect of the plant belts at two seawalls.

[0017] Preferably, the planting belt in step S4 or S5 is affected by many factors such as high-salinity seawater and waves, currents, tidal changes, etc., and vegetation is not easy to survive. The plant types in the planting belt are preferably local vegetation with strong resistance to erosion and high salt and alkalinity tolerance, including reeds, sea sedge, short-leaved sedge, saltwort, seashore hibiscus and tamarisk.

[0018] Preferably, the plant type of the planting belt in step S4 or S5 is selected according to the tidal level of the planting belt. When the average height of the planting belt is greater than the tidal level and the height of the plants below the water surface is the largest, the wave-breaking effect is best.

[0019] A method for determining the top elevation of an ecological landscape type disaster reduction seawall comprises the following steps: Step 1: Determine the design high tide (water) level h p The value of is determined based on long-term continuous tidal (water) level hydrological data. When the data is lacking, the extreme value synchronous difference ratio method is used to conduct synchronous correlation analysis with the long-term tidal (water) level station data nearby with data of no less than 20 consecutive years; Step 2: Determine the wave height R F , and its calculation formula is , where R is the wave run-up of a positive regular wave on a slope seawall without the influence of a planting belt, and R wL1 is the wave height attenuation rate of the primary planting zone, R wL2 is the wave height attenuation rate of the secondary planting zone; Step 3: Determine the value of the safety height increase value A, which is determined by referring to Table 8.3.1 of the Seawall Engineering Design Specification SL435-2008.

[0020] Step 4: Determine the dike top elevation Z P The calculation formula is: , where h p is the design high tide (water) level, R F is the wave climbing value, and A is the safety heightening value.

[0021] Preferably, the wave height R calculation method in step 2 is as follows: The calculation formula of wave height R is: , starting from the static water level; R1 is the wave height when KΔ=1, H=1; H is the wave height; KΔ is the roughness permeability coefficient related to the slope protection structure type; , (R1) m is the maximum climbing height corresponding to a certain d / L; M is a function related to the m value of the slope; R(M) is the climbing height function.

[0022] , L is the wavelength; d is the water depth in front of the dike; for the wave climbing calculation of the composite slope dike with a platform, first determine the reduced slope coefficient m of the section e , and then the slope coefficient is m e The single slope section calculation formula determines the climbing value. When the upper and lower slopes are the same, , m 上 is the slope rate above the platform, is the water depth on the platform, , B is the platform width; ; ; Preferably, the wave height attenuation rate R of the primary planting zone in step 2 is wL1and the wave height attenuation rate R of the secondary planting zone wL2 The calculation method is as follows: The wave height attenuation rate is estimated using an empirical formula: ; L is the width of the vegetation belt assessed for wave and disaster reduction; is the wave height attenuation coefficient, and its theoretical expression is derived based on the linear wave theory: ; in is the plant drag coefficient, ; D is the plant area per unit vertical height, i.e., the vertical average plant diameter; N is the number of plants per unit area, in units of plants / m 2 ; It is the effective wave height of the sea waves in front of the vegetation area caused by the storm surge; k is the wave number at the front end of the plant area; h It is the storm tide level calculated from the ground of the measuring point in the vegetation area, that is, the tide level in the vegetation area; is the height of the plant below the water surface; is the empirical coefficient, , , ; is the plant volume percentage; is the Reynolds number, ,in is the maximum velocity of water particles under the action of waves; υ is the kinematic viscosity coefficient of seawater; , T is the wave period.

[0023] Compared with the prior art, the advantages and effects of the present invention are as follows: 1. The present invention provides an ecological landscape disaster reduction seawall. On the basis of ensuring safety, the seawall is designed with ecological landscape, so that the seawall can intercept silt and purify water; it can weaken wave energy and reduce the threat of marine disasters; at the same time, it can also enhance the hydrophilicity of the seawall and provide space for people to have leisure activities.

[0024] 2. The present invention provides a design method for an ecological landscape type disaster reduction seawall, which can optimize the ecological landscape type disaster reduction seawall and improve the wave dissipation effect of the seawall.

[0025] 3. The present invention provides a method for determining the crest elevation of an ecological landscape type disaster reduction seawall, which can determine the cross-sectional form of the seawall based on the wave height and the height difference between the tide level and the road surface, which can effectively reduce the crest elevation, reduce engineering costs, and increase the ecological function value of the seawall.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings as follows.

[0027] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0029] in: Figure 1 A schematic diagram of a structural cross section of an ecological landscape type disaster reduction seawall according to the present invention; Figure 2 A schematic diagram of calculating the crest elevation of an ecological landscape disaster reduction seawall according to the present invention; Figure 3 It is a schematic diagram of the application of an ecological landscape type disaster reduction seawall of the present invention.

[0030] Explanation of the accompanying drawings: 1-embankment foot; 2-gabion mesh box; 3-first-level planting belt; 4-planting soil; 5-dry block stone; 6-gravel; 7-anti-filtration non-woven fabric; 8-reinforced Mac pad; 9-second-level planting belt; 10-stone permeable prism; 11-hydrophilic platform; 12-wave-breaking wall; 13-road; 14-dump stone; 15-original soil; 20-first-level gentle slope; 30-first-level planting platform; 40-second-level gentle slope; 50-second-level planting platform; 60-third-level gentle slope. DETAILED DESCRIPTION

[0031] To make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all of the embodiments. In the following description, specific details such as specific configuration and components are provided only to help fully understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and brevity, the description of known functions and structures is omitted in the embodiment.

[0032] It should be understood that the references to "one embodiment" or "this embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present application. Therefore, the references to "one embodiment" or "this embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0033] In addition, the present application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0034] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" in this article describes another type of association object relationship, indicating that there can be two relationships. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0035] The term "at least one" in this article is merely a description of the association relationship of associated objects, indicating that there may be three relationships. For example, at least one of A and B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0036] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusions. Example 1

[0037] This embodiment provides an ecological landscape type disaster reduction seawall, please refer to Figure 1 , an ecological landscape type disaster reduction seawall, the cross-section of which is a multi-level composite type with a gentle slope into the sea, including a planting belt, a seawall structure, dump stones 14 and original soil 15; The dumping stone 14 covers the upper part of the original soil 15; The seawall structure covers the top of the fill stone 14 .

[0038] The seawall structure comprises a footing 1 on the sea side of the seawall, a primary planting platform 30, a gentle slope, a primary planting platform 50, a hydrophilic platform 11, a wave-breaking wall 12, and a road 13, which are arranged in sequence from sea to land.

[0039] The seawall structure is composed of the seawall underwater area, water level change area, water area and seaward side from the sea to the land; The underwater area of ​​the seawall is located below the tide level on the sea side, including the foot 1 and the first-level gentle slope 20 on the sea side of the seawall; The water level change zone is located above the sea side tide level and below the average tide level, and includes a first-level planting platform 30 and a second-level gentle slope 40; The above-water area is located above the average tide level and is considered as the land area, including a first-level planting platform 50, a third-level gentle slope 60, a hydrophilic platform 11 and a wave-breaking wall 12; The seaward side, located behind the wave-breaking wall 12, includes a road 13 for pedestrians and vehicles to pass through.

[0040] Furthermore, in the ecological landscape type disaster reduction seawall, the surface protection and the embankment foot 1 give priority to safety and adopt a structure with multiple gaps and rough surface.

[0041] Furthermore, in the ecological landscape type disaster reduction seawall, when located in a sea area with strong wave energy, it is advisable to strengthen its wave-breaking measures, such as increasing the coverage rate of the planting belt to reduce the elevation of the embankment top and enhance the ecological function of the embankment body.

[0042] Furthermore, in the ecological landscape type disaster reduction seawall, the seawall section design should appropriately consider the hydrophilicity and the ornamental value of the seawall, and the surface slope should be appropriately slowed down.

[0043] Furthermore, in the ecological landscape disaster reduction seawall, green and environmentally friendly harmless building materials suitable for the local marine ecosystem should be used, and new materials such as ecological blocks, vegetated geotextile mats, and porous permeable concrete are encouraged to facilitate plant growth and algae and shellfish attachment, thereby improving biodiversity. For seawalls made of concrete, mortar masonry and other materials, ecological planting troughs should be set up on the waterside for greening.

[0044] Furthermore, in the ecological landscape type disaster reduction seawall, if artificial blocks are used for surface protection, the void ratio of the surface protection should be above 40%. The seawall with natural block dry masonry or vegetation for surface protection has a high plant coverage rate and better ornamental value, so the void ratio can be ignored.

[0045] Furthermore, in the ecological landscape type disaster reduction seawall, when an impermeable slope protection is required due to factors such as anti-seepage, the impermeable slope protection should not be higher than the average tide level by 0.3~0.5 m.

[0046] Technical effect of this embodiment: An ecological landscape disaster reduction seawall can reduce the elevation of the embankment top and enhance the ecological function of the embankment body by increasing the coverage rate of the planting belt. The slope of the protective surface should be appropriately slowed down to increase the hydrophilicity and ornamental value of the seawall. By using new materials, plant growth and algae and shellfish attachment can be improved, thereby improving biodiversity. Example 2

[0047] This embodiment mainly provides an ecological landscape type disaster reduction seawall, which is further designed on the basis of embodiment 1.

[0048] Preferably, the hydrophilic platform 11 is located in front of the wave-breaking wall 12 for pedestrians to walk and enjoy the landscape; Preferably, the wave-breaking wall 12 has an "L"-shaped cross section and is located on the top of the embankment to reduce the amount of overtopping and protect pedestrians on the seaward side; Preferably, the dumping stone 14 is mainly composed of crushed stone 6, sand and clay, and is formed by artificial backfill; the diameter of the crushed stone 6 is 5.0 to 35.0 cm, and the sand and clay are filling materials with good drainage performance.

[0049] Preferably, the embankment foot 1 adopts a structure with multiple gaps and a rough surface; Preferably, the structure of the road 13 is, from top to bottom, a road surface, a sea-facing side protection surface, and a block stone permeable prism 10; Preferably, the first level gentle slope 20, the first level planting platform 30 and the second level gentle slope 40 are located below 0.3 m above the average tide level, and adopt a multi-void, rough surface structure, and dry masonry stones 5, crushed stones 6 and anti-filtration non-woven fabrics 7 are arranged in sequence from top to bottom; Preferably, the first-level planting platform 50, the hydrophilic platform 11 and the seaward side protection surface adopt a multi-void and rough surface structure, and dry masonry blocks 5 and crushed stones 6 are arranged in sequence from top to bottom; Preferably, the three-level gentle slope 60 connects the first-level planting platform 50 and the hydrophilic platform 11, and the slope of the three-level gentle slope 60 is less than or equal to 1:3. The block stone permeable prisms 10 and the dry-laid block stone 5 are arranged in sequence from top to bottom, without considering the porosity of the dry-laid block stone 5, so that a small amount of overtopping waves can enter the soil below through the gaps between the blocks.

[0050] Preferably, air vents are arranged inside the permeable stone prism 10 to prevent water from accumulating on the hydrophilic platform 11 due to waves and on the road 13 due to rain.

[0051] Preferably, a row of gabion boxes 2 are arranged on the primary planting platform 30, in which blocks of stone and planting soil 4 are backfilled, and a primary planting belt 3 is planted in the soil; Preferably, the first-level planting platform 50 is provided with a reinforced Mac mat 8 and planting soil 4, and a second-level planting belt 9 is planted in the soil. The pore water in the reinforced Mac mat 8 creates conditions for water flow, realizes the natural exchange of water and soil, and enables the second-level planting belt 9 to grow naturally. ; Preferably, the plant types of the primary planting belt 3 include reeds and Suaeda salsa, and the plant types of the secondary planting belt 9 include Hibiscus sylvestris and Tamarix chinensis; Preferably, the total width of the planting belt is selected from 25m-400m, and the width of the planting belt is arranged in a decreasing order. The first-level planting belt 3 has the largest width, and the width of the subsequent first-level planting belts 3 decreases successively. The width of the first-level planting belt 3 does not exceed twice the width of the second-level planting belt 9, and so on.

[0052] Preferably, the elevation of the wave-breaking wall 12 is the elevation of the top of the embankment; Preferably, the elevation of the embankment top is determined by the planting density, width and plant species of the first-level planting belt 3 in the water level change area and the second-level planting belt 9 in the water area. The larger the planting density N, the larger the planting width L, and the larger the plant diameter D, the smaller the wave height R attenuates after passing through the green plant area, thereby reducing the required embankment top elevation Zp.

[0053] Preferably, Technical effect of this embodiment: an ecological landscape disaster reduction seawall, which, on the basis of ensuring safety, carries out ecological landscape design of the seawall, can intercept silt and purify water; can weaken wave energy and reduce the threat of marine disasters; at the same time, it can also enhance the hydrophilicity of the seawall and provide space for people to have leisure activities. Example 3

[0054] Based on the above embodiments 1-2, this embodiment mainly provides a design method for an ecological landscape type disaster reduction seawall, including the following steps: Step S1, determine the seawall area, fill the landfill 14 on the original soil 15 foundation, and lay the anti-filtration non-woven fabric 7 on the original soil 15 and the landfill 14; Step S2, arranging crushed stones 6 on the reverse filter nonwoven fabric 7 and then laying dry masonry blocks 5; Step S3, a gabion box 22 is placed on the upper part of the dry block stone 5 platform in the water level change area, and then filled with stones and backfilled with planting soil 4, the thickness of the planting soil 4 does not exceed the gabion box 22, and a primary planting belt 3 is planted in the gabion box 22; Step S4: The water level change area is a salt marsh-like ecological environment, and the first-level planting belt 3 is planted inside to determine the target plants according to the natural geographical conditions of the project area; Step S5, a reinforced Mac mat 8 is laid on the upper part of the dry block stone 5 platform in the water area, and the planting soil 4 is backfilled, and a secondary planting belt 9 is set in the planting soil 4. The reinforced Mac mat 8 creates conditions for the flow of water, realizes the natural exchange of water and soil, and is convenient for planting small trees that can grow in coastal saline-alkali land; Step S6, the above-water planting platform is connected to the hydrophilic platform 11 on a slope, a block stone permeable prism 10 is placed, and dry masonry blocks 5 are laid below to facilitate a small amount of overtopping waves to enter the soil below through the gaps between the blocks, thereby reducing water accumulation on the hydrophilic platform 11; Step S7: a hydrophilic platform 11 is provided in the water area for pedestrians to walk and enjoy the scenery. Pedestrians are not recommended to enter at extreme high tide levels. Step S8, considering the extreme high tide level, a wave-breaking wall 12 is set on the top of the dike, and its elevation is determined by referring to the wave height after the wave-breaking effect of the plant belts at two seawalls.

[0055] Furthermore, in the ecological landscape disaster reduction seawall and its design method S3, the seawall foot 1 and the stone guard on the sea side are susceptible to erosion by wind, waves and currents all year round, which puts forward higher safety requirements for the anti-scouring ability and overall stability of the seawall foot 1 and the seaside protective material. In order to prevent the seaside foot 1 and the surface of the protective material from being damaged by waves and water flow and to ensure the overall stability of the structure, combined with the actual project situation, the ecologicalization of the seawall can be selected to be carried out above the high tide beach where the wind, waves and currents are relatively small, and the gabion box 22 structure that can effectively resist the scouring of waves and tides is used as the protective material, so that the silt carried by the tide is gradually deposited, and a green plant platform is gradually formed along the coast to assist the survival of green plants.

[0056] Furthermore, in the ecological landscape type disaster reduction seawall and its design method S4 and S5, the planting belt is completely different from the environment of conventional terrestrial green plants. The surface of the planting belt is affected by many factors such as high-salinity seawater, waves, currents, and tidal changes. Especially when planting vegetation on the seaside, it is susceptible to erosion by wind and waves and ocean currents all year round, and it is difficult for vegetation to survive. Therefore, when selecting vegetation, try to choose vegetation with strong erosion resistance and high salt and alkalinity tolerance, and give priority to local vegetation, such as reed, sea sedge, short-leaved sedge, salt-land salsa, seashore hibiscus or tamarisk.

[0057] Furthermore, in the ecological landscape type disaster reduction seawall and its design method S4 and S5, the planting belt needs to be selected according to the tide level of the greening area, and the average height of the planting belt is greater than the tide level. When the height of the plants below the water surface is the largest, the wave dissipation effect is the best. The dominant species of coastal salt marsh vegetation in my country mainly include plants such as reed, sea sedge, saltwort, and short-leaved sedge. Referring to the "Technical Guidelines for Ecological Disaster Reduction and Restoration in Coastal Zones Part 3: Salt Marsh" T / CAOE 21.3-2020, if the design adopts a multi-level composite section, the height of reed and saltwort is relatively high, about 2-3m, which can meet the wave dissipation needs of the lower greening area; and due to the height difference between the platforms, the tide level of the higher greening area is lower, and the wave height is reduced after the wave dissipation in the lower greening area, so the demand for plant height is relatively low, and seaside hibiscus or tamarisk can be selected, with a height of about 0.5-1m.

[0058] Technical effect of this embodiment: a design method for an ecological landscape type disaster reduction seawall is provided, which can optimize the ecological landscape type disaster reduction seawall and improve the wave-breaking effect of the seawall. Example 4

[0059] Based on the above-mentioned embodiments 1-2, this embodiment mainly provides a method for determining the top elevation of an ecological landscape type disaster reduction seawall. Please refer to Figure 2 The following steps are involved: Step 1: Determine the design high tide (water) level h p The value of is determined based on long-term continuous tidal (water) level hydrological data. When the data is lacking, the extreme value synchronous difference ratio method is used to conduct synchronous correlation analysis with the long-term tidal (water) level station data nearby with data of no less than 20 consecutive years; Step 2: Determine the wave height R F , and its calculation formula is , where R is the wave run-up of a positive regular wave on a slope seawall without the influence of a planting belt, and R wL1 is the wave height attenuation rate of the first-level planting zone 3, R wL2 is the wave height attenuation rate of the secondary planting zone 9; Step 3: Determine the value of the safety height increase value A, which is determined by referring to Table 8.3.1 of the Seawall Engineering Design Specification SL435-2008.

[0060] Step 4: Determine the dike top elevation Z P The calculation formula is: , where h p is the design high tide (water) level, R F is the wave climbing value, and A is the safety heightening value.

[0061] Preferably, the wave height R calculation method in step 2 is as follows: The calculation formula of wave height R is: , starting from the static water level; R1 is the wave height when KΔ=1, H=1; H is the wave height; KΔ is the roughness permeability coefficient related to the slope protection structure type; , (R1) m is the maximum climbing height corresponding to a certain d / L; M is a function related to the m value of the slope; R(M) is the climbing height function.

[0062] , L is the wavelength; d is the water depth in front of the dike; for the wave climbing calculation of the composite slope dike with a platform, first determine the reduced slope coefficient m of the section e , and then the slope coefficient is m e The single slope section calculation formula determines the climbing value. When the upper and lower slopes are the same, , m 上 is the slope rate above the platform, is the water depth on the platform, K b =1+3B / L, B is the platform width; ; Preferably, the wave height attenuation rate R of the primary planting belt 3 in step 2 is wL1 and the wave height attenuation rate R of the secondary planting zone 9 wL2 The calculation method is as follows: The wave height attenuation rate is estimated using an empirical formula: ; L is the width of the vegetation belt assessed for wave and disaster reduction; is the wave height attenuation coefficient, and its theoretical expression is derived based on the linear wave theory: ; in is the plant drag coefficient, ; D is the plant area per unit vertical height, i.e., the vertical average plant diameter; N is the number of plants per unit area, in units of plants / m 2 ; It is the effective wave height of the sea waves in front of the vegetation area caused by the storm surge; k is the wave number at the front end of the plant area; h It is the storm tide level calculated from the ground of the measuring point in the vegetation area, that is, the tide level in the vegetation area; is the height of the plant below the water surface; is the empirical coefficient, , , ; is the plant volume percentage; is the Reynolds number, ,in is the maximum velocity of water particles under the action of waves; υ is the kinematic viscosity coefficient of seawater; , T is the wave period.

[0063] Furthermore, in the ecological landscape disaster reduction seawall described, referring to the Technical Guidelines for Ecological Disaster Reduction and Restoration in Coastal Zones Part 3: Salt Marsh T / CAOE 21.3-2020, the wave-breaking effect of seawall plants is closely related to the total width of the planting belt and the height of the plants below the water surface, and has nothing to do with the wavelength of the waves. The width of the planting belt can be 25-400m. Taking into account the different wave action conditions, the width of the planting belt is adjusted accordingly according to the wave height. If the wave height is below 2m, the total width of the planting belt takes the minimum value of 25m. The number of levels of the multi-level composite section does not exceed two, and the width of the first-level platform is the largest, not exceeding twice that of the second-level platform.

[0064] Furthermore, in the ecological landscape type disaster reduction seawall, the number of composite sections to be used can be determined according to the wave height and the height difference between the tide level and the road surface. If the wave height is below 2m and the height difference between the designed high tide level and the road surface is below 1m, a two-level composite section can be used. The elevation of the first planting platform is 1-2m below the designed high tide level, and 2-3m seawall plants are used to eliminate waves. The elevation of the second planting platform is 0-1m below the designed high tide level, and 0.3-1m seawall plants are used to eliminate waves. This structural design maximizes the wave height attenuation rate while maximizing economic benefits. If the wave height is greater than 2m and the height difference between the tide level and the road surface is less than the wave height, a three-level composite section can be used, and the height of the seawall plants can be determined according to the water depth and wave height corresponding to different platforms.

[0065] The technical effect of this embodiment is as follows: a method for determining the crest elevation of an ecological landscape type disaster reduction seawall is provided, which can determine the cross-sectional form of the seawall based on the wave height and the height difference between the tide level and the road surface, which can effectively reduce the crest elevation, reduce engineering costs, and increase the ecological function value of the seawall. Example 5

[0066] Based on the above-mentioned embodiments 1-4, this embodiment mainly provides an application of an ecological landscape type disaster reduction seawall in some coastal areas where there are ecological landscape and disaster prevention and reduction needs.

[0067] This type of project is located in the sea-land transition zone, which is periodically or intermittently affected by ocean tides and is covered with silty or sandy intertidal wetland ecosystems with herbs or low shrubs, with a vegetation coverage of ≥30%.

[0068] As a preferred embodiment, in the ecological landscape type disaster reduction seawall, in order to better improve the viewing effect and reduce the amount of overtopping without increasing the elevation of the levee top, the seawall plants (3) (9) are arranged in the water level change area and the water area. The plant arrangement plan requires on-site observation. First, the cross-section observation method is adopted. The cross-section should be parallel to the wave direction as much as possible. The cross-section plant density and vegetation belt width should be able to better reflect the situation of the entire area. When the distribution area characteristics are quite different, multiple cross-sections should be selected. Each cross-section has no less than two measuring points, which are located at the edge of the vegetation area on the sea side (seaward point) and the edge of the vegetation area on the land side (landward point).

[0069] Secondly, the disaster reduction function on-site observation elements include wave height and tide level at the seaward and landward points. The observation methods of wave height, period and other wave elements and tide level shall be carried out in accordance with the relevant provisions of the Marine Survey Specification Part 2: Marine Hydrological Observation (GB / T 12763.2). The disaster reduction function on-site observation period should include the entire storm surge impact period (1 to 3 days before the storm surge warning until the storm surge warning is lifted).

[0070] According to the local marine disaster reduction needs and combined with regional storm surge and other marine dynamic disaster conditions, an appropriate expected wave height attenuation rate is set for the restoration project area. The value should be greater than 30% during the growth and maturity period of seawall plants (3) (9); In order to achieve the expected wave height attenuation rate, the required vegetation width under different sea conditions should be calculated based on the growth parameters of the selected seawall plants (3) (9) at maturity; For the same expected wave height attenuation rate, there are many combinations of seawall plant (3) (9) planting strip widths for reference. In actual planting design, the appropriate planting strip width should be selected from the perspective of the most reasonable economic cost.

[0071] The on-site observation method is suitable for areas to be assessed that are frequently affected by disasters and have economic conditions that permit. In the year when the salt marsh marine disaster reduction function assessment is carried out, there should be at least one storm surge that has a significant impact on the assessment area.

[0072] Please refer to Figure 3 , excavation bottom elevation -1.0m, wavelength 70m, period 10s, water depth in front of the embankment 3.3m, wave height 2m.

[0073] The seawall is selected as a two-level composite section. First, when the wave height is 2m or less, the total width of the planting belt takes the minimum value of 25m, and the number of levels of the multi-level composite section does not exceed two. Second, because the road surface elevation of this embodiment is 3.08m, the height difference between the designed high tide level and the road surface is less than 1m, and the wave height is 2m or less, a two-level composite section can be used.

[0074] The width of the first-level platform is the largest, no more than twice that of the second-level platform. The design elevation of the platform depends on two points, one is the design high tide level, and the other is the height of the plants selected for the planting platform. The design elevation of each level of planting platform must meet the requirement that its elevation plus the height of the plants planted on it is greater than the design high tide level. The design high tide level is 2.3m. The plants selected for the first-level platform are reeds or alkali sedge, with a height of 2-3m, so the design elevation of the first-level platform must be greater than 0.3m. The plants selected for the second-level platform are seaside hibiscus or tamarisk, with a height of about 0.5-1m, so the design elevation of the second-level platform must be greater than 1.7m.

[0075] In summary, the seawall of this project is a two-level composite section, the total width of the planting belt is 25m, the first-level platform elevation is 1m, the width is 15m, the second-level platform elevation is 1.86m, the width is 10m. The top elevation of the embankment is 3.23m according to the following calculation results.

[0076] Elevation Z P It should be based on the design high tide (water) level h p 、Wave climbing R F And the safety height value A is calculated to meet , where the design high tide (water) level h p 2.3m, R F The calculated value is 0.115m, and the safety height increase value A is 0.8m.

[0077] According to S1, ; According to S31, ; According to S32, , , ; According to S33, ; According to S34, ; According to S3, K Δ =0.9 According to S3, the wave-dissipating effect of the seawall plants reed or Suaeda salsa (3) in the water level fluctuation area is first calculated to obtain the wave height attenuation rate of the first green plant area. ,in as well as ,but ; According to S3, the wave attenuation effect of the seawall plants Hibiscus tamarisk (9) in the water area is calculated again based on the wave attenuation of the first green area, and the wave height attenuation rate R of the second green area is obtained. wL2 ,in , ,but ; Finally, it is concluded .

[0078] As a preferred embodiment, in the described ecological landscape type disaster reduction seawall and design method, when the elevation of the levee top is 3.215m in the calculation, the elevation of the hydrophilic platform 11 is 3.23m, which can ensure that at high tide, waves will not affect the safety of pedestrians. At the same time, a wave-breaking wall 12 is added behind the hydrophilic platform 11 to reduce the amount of overtopping and protect pedestrians and the seawall structure on the back side during storm surges and extreme high tides.

[0079] Technical effect of this embodiment: It can be seen from the calculation that the original wave height in the underwater area of ​​the seawall is 1.68m. The seawall plants in the first water level change area weakened the wave height by 64%. The seawall plants in the second above-water area further reduced the wave height by 81% on the basis of the weakened wave height. Under the wave-breaking and disaster-reducing effect of the two seawall plants, the wave height was reduced to 0.115m, which was almost negligible when reaching the hydrophilic platform 11. At the same time, the elevation of the embankment top was also reduced, which reduced the engineering cost and increased the ecological function value of the seawall.

[0080] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An ecological landscape disaster reduction seawall, characterized in that: An ecological landscape disaster reduction seawall, the cross-section of which is a multi-level composite type with a gentle slope into the sea, comprising a planting belt, a seawall structure, dump stones (14) and original soil (15); The dumping stones (14) cover the upper part of the original soil (15); The seawall structure covers the upper part of the dumpstone (14); The seawall structure comprises a footing (1) on the seaward side of the seawall, a primary planting platform (30), a gentle slope, a secondary planting platform (50), a hydrophilic platform (11), a wave-breaking wall (12), and a road (13), which are arranged in sequence from sea to land; The seawall structure is composed of the seawall underwater area, water level change area, above-water area and the seaward side from the sea to the land; The underwater area of ​​the seawall is located below the tide level on the sea side and includes the foot of the seawall (1) and the first gentle slope (20) on the sea side; The water level fluctuation zone is located above the sea side tide level and below the average tide level, and includes a first-level planting platform (30) and a second-level gentle slope (40); The above-water area is located above the average tide level and is considered as the land area, including a secondary planting platform (50), a third-level gentle slope (60), a hydrophilic platform (11) and a wave-breaking wall (12); The seaward side, located behind the wave-breaking wall (12), includes a road (13) for pedestrians and vehicles to pass through.

2. The ecological landscape disaster reduction seawall according to claim 1, characterized in that: The fill stone (14) comprises crushed stone (6), sand and clay; wherein the diameter of the crushed stone (6) is 5.0 to 35.0 cm.

3. The ecological landscape disaster reduction seawall according to claim 1, characterized in that: The embankment foot (1) adopts a structure with multiple gaps and a rough surface; The structure of the road (13) is, from top to bottom, a road surface, a sea-facing side protection surface, and a block stone permeable prism (10).

4. The ecological landscape disaster reduction seawall according to claim 1, characterized in that: The first level gentle slope (20), the first level planting platform (30) and the second level gentle slope (40) are located below 0.3 m above the average tide level and have a multi-void structure with a rough surface. Dry masonry stones (5), crushed stones (6) and anti-filtration non-woven fabrics (7) are arranged in sequence from top to bottom. The secondary planting platform (50), the hydrophilic platform (11) and the seaward side protection surface adopt a multi-void structure with a rough surface, and are arranged with dry masonry blocks (5) and crushed stones (6) in sequence from top to bottom; The three-level gentle slope (60) connects the secondary planting platform (50) and the hydrophilic platform (11), the slope of the three-level gentle slope (60) is less than or equal to 1:3, and the block stone permeable prisms (10) and the dry block stone (5) are arranged in sequence from top to bottom, without considering the porosity of the dry block stone (5); The block stone water-permeable prism (10) is internally provided with an exhaust hole.

5. The ecological landscape disaster reduction seawall according to claim 4, characterized in that: The elevation of the hydrophilic platform (11) is the elevation of the top of the embankment; The dike top elevation is determined by the planting density, width and plant species of the primary planting belt (3) in the water level fluctuation area and the secondary planting belt (9) in the water area. The greater the planting density N, the greater the planting width L, and the greater the plant diameter D, the smaller the wave height R will be after passing through the green plant area, so that the required dike top elevation Z p Reduce.

6. The ecological landscape disaster reduction seawall according to claim 4, characterized in that: A row of gabion boxes (2) are arranged on the primary planting platform (30), which are backfilled with stone blocks and planting soil (4), and a primary planting belt (3) is planted in the soil; A reinforced Mac mat (8) and planting soil (4) are arranged on the secondary planting platform (50), and a secondary planting belt (9) is planted in the soil.

7. The ecological landscape disaster reduction seawall according to claim 6, characterized in that: The plant types of the primary planting belt (3) include reeds and Suaeda salsa, and the plant types of the secondary planting belt (9) include Hibiscus syriacus and Tamarix chinensis.

8. The ecological landscape disaster reduction seawall according to claim 7, characterized in that: The total width of the planting belt is selected from 25m-400m, and the width of the planting belt is arranged in a decreasing order. The first-level planting belt (3) has the largest width, and the widths of the subsequent-level planting belts (3) decrease in sequence. The width of the first-level planting belt (3) does not exceed twice the width of the second-level planting belt (9), and so on.

9. A method for designing an ecological landscape disaster reduction seawall according to any one of claims 1 to 8, comprising the following steps: Step S1, determining the seawall area, filling the landfill (14) on the original soil (15) foundation, and laying the anti-filtration non-woven fabric (7) on the original soil (15) and the landfill (14); Step S2, arranging crushed stones (6) on the reverse filter nonwoven fabric (7) and then laying dry masonry stones (5); Step S3, a gabion box (2) is placed on the upper part of the dry block stone (5) platform in the water level fluctuation area, and then the inside is filled with stones and backfilled with planting soil (4), the thickness of the planting soil (4) does not exceed the gabion box (2), and a primary planting belt (3) is planted in the gabion box (2); Step S4: The water level change area is a salt marsh-like ecological environment, and a primary planting belt (3) is planted inside to determine the target plants according to the natural geographical conditions of the project area; Step S5, laying a reinforced Mac mat (8) on the upper part of the dry block stone (5) platform in the water area, backfilling the planting soil (4), and setting a secondary planting belt (9) in the planting soil (4). The reinforced Mac mat (8) creates conditions for the flow of water, realizes the natural exchange of water and soil, and facilitates the planting of small trees that can grow in coastal saline-alkali land; Step S6, the above-water planting platform is connected to the hydrophilic platform (11) on a slope, a permeable stone prism (10) is placed, and dry masonry stones (5) are laid underneath to facilitate a small amount of overtopping waves to enter the soil below through the gaps between the stones, thereby reducing water accumulation on the hydrophilic platform (11); Step S7: a hydrophilic platform (11) is provided in the water area for pedestrians to walk and enjoy the scenery. Pedestrians are not recommended to enter during extreme high tides. Step S8: Considering the extreme high tide level, a wave-breaking wall (12) is set on the top of the dike, and the top elevation of the ecological landscape type disaster reduction seawall is determined.

10. A method for determining the crest elevation of an ecological landscape disaster reduction seawall according to claim 9, comprising the following steps: Step 1: Determine the value of the design high tide (water) level hp by taking the value based on the long-term continuous tidal (water) level hydrological data. If there is a lack of such data, use the extreme value synchronous difference ratio method to conduct synchronous correlation analysis with the long-term tidal (water) level station data of nearby with no less than 20 consecutive years of data; Step 2: Determine the wave height R F , and its calculation formula is , where R is the wave run-up of a positive regular wave on a slope seawall without the influence of a planting belt, and R wL1 is the wave height attenuation rate of the primary planting zone (3), R wL2 is the wave height attenuation rate of the secondary planting zone (9); Step 3, determine the value of the safety height value A, the value is determined by referring to Table 8.3.1 of the seawall engineering design specification SL435-2008; Step 4: Determine the dike top elevation Z P The calculation formula is: , where h p is the design high tide (water) level, R F is the wave climbing value, and A is the safety heightening value.

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