Construction method of coastal plant dune

Abstract

The invention provides a construction method of a coastal plant dune, which comprises the following steps: a plurality of dune protection zones are arranged on a sand beach at the middle upper part of a high tidal zone or on a tidal zone, and each protection zone comprises an outer layer close to the sea, an inner layer close to the coast and a stacking area formed by the outer layer and the inner layer; sand penetrates through the outer layer to enter the accumulation area until a sand dune with a target diameter and a target height is formed in the accumulation area, at least two zones of vegetation are planted on the sand dune from sea to land according to the salt tolerance grade so as to form a shrub sand dune, and the shrub sand dune can settle sand carried in wind or seawater so as to form a shrub sand dune. According to the method, a manual intervention method is adopted, the sand dunes are rapidly constructed, the positive effect on formation and stabilization of irrigation and grass dunes is achieved, and the effects of wave dissipation and bank protection on the sandy coast in the erosion state are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of coastal protection, in particular to a method for constructing coastal plant dunes. Background Art

[0002] Many sandy coasts in my country are eroded, affecting the safety of life and property of people in villages and aquaculture facilities behind the coast. Traditional coastal protection methods mainly rely on physical barriers, such as seawalls and breakwaters, which are often costly and have an impact on the ecological environment. Coastal dunes are important geomorphic units of sandy coasts. They not only provide "flexible" protection against extreme ocean dynamics, but also provide valuable living space for coastal animals and plants. At present, there are many methods for artificial sand dune restoration, such as CN116368983A, a method for repairing and maintaining coastal sand dunes, but this method has the following problems: the amount of engineering work is large, and the artificially piled sand dunes are easily carried away by wind or waves; another example is CN219612681U, a wind-proof and sand-blocking structure for covering coastal sand dunes, and CN114258815A, a method for rapid sand fixation of mobile sand dunes. These two methods only consider the impact of wind and sand, but do not consider the impact of water flow and waves on sand dunes; another example is CN116377946A, an ecological restoration method for optimizing the design of sandy coastal vegetation combinations, but this method lacks specific and operational methods for the plant species, layout, planting and maintenance measures adopted, and different plants have different adapted elevations and flooding degrees in coastal areas, which affects the growth of plants; therefore, a method for constructing coastal plant dunes is designed to address the problems existing in the above-mentioned prior art. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a method for constructing coastal plant dunes, which can effectively solve the above problems.

[0004] In order to achieve the above object, the technical solution provided by the present invention is as follows: The present invention provides a method for constructing coastal plant dunes, comprising: A plurality of dune protection belts are arranged on the beach in the middle and upper part of the high tide zone or the supratidal zone, wherein the protection belts include an outer layer close to the sea and an inner layer close to the coast, and an accumulation area formed by the outer layer and the inner layer; The sand passes through the outer layer and enters the accumulation area until a sand dune of a target diameter and a target height is formed in the accumulation area, and at least two vegetation belts are planted on the sand dune from sea to land according to the salt tolerance level to form a shrub dune, wherein the shrub dune can settle the sand carried by the wind or sea water and can continuously accumulate the sand dune as the vegetation is generated; The spacing of the dune protection belts is S=W×0.75, where W is the desired width of the dune bottom; the height of the dune protection belt Ha=0.3×D, where D is the desired maximum height of the dune; the number of dune protection belts N=coastline length / (W+S), where (W+S) is the space occupied by each dune protection belt; The position of the dune protection zone in the high tide zone is pi=L+(HL)×0.6; the position of the dune protection zone in the supratidal zone is ps=H+0.5×D; L is the average height of the high tide line of neap tide, H is the average height of the high tide line of spring tide, and (HL) is the height range of the coastal high tide zone.

[0005] As a further improvement, the dune construction device includes: a plurality of dune protection belts are arranged in a plum blossom shape on the beach.

[0006] As a further improvement, the dune protection belt includes: a plurality of fixed piles, a coarse mesh group, a fine mesh group and a fixing member group, the fixed piles are fixed on the beach, the coarse mesh group is arranged on the fixed piles to form the outer layer, and the fine mesh group is arranged on the fixed piles to form the inner layer.

[0007] As a further improvement, the coarse mesh group is provided with a third coarse mesh, a second coarse mesh and a first coarse mesh in sequence from top to bottom.

[0008] As a further improvement, the mesh size of the third coarse net is 40-50 meshes, the mesh size of the second coarse net is 30-40 meshes, and the mesh size of the first coarse net is 20-30 meshes.

[0009] As a further improvement, the fine mesh group is provided with a second fine mesh and a first fine mesh in sequence from top to bottom.

[0010] As a further improvement, the mesh size of the second fine net is 50-60 meshes, and the mesh size of the first fine net is 60-70 meshes.

[0011] As a further improvement, the sand dune is planted with coastal herbs on a side close to the outer layer, and the sand dune is planted with salt-alkali tolerant shrubs on a side close to the inner layer.

[0012] As a further improvement, the coastal herbaceous plants are one or more of seahorse, saddle vine, seaside evening primrose, hawthorn, dogtooth grass, and salt shrew tail millet; the salt-alkali tolerant shrubs are one or more of bitter orange, simple vitex, thousand-headed casuarina, and grassy seahorse.

[0013] The beneficial effects of the present invention are: 1. The present invention designs the location, arrangement, height of the protection belt and elevation of the sand dunes, so that the formed sand dunes can effectively reduce the impact of waves on the coast, play a good role in protecting the stability of the coast, and the formed sand dunes are stable and not easily destroyed by wind or sea water; the sand dune protection belt set up has a strong ability to capture sand, and the surface of the sand dunes is covered with plants. After the plants grow, they have a certain sand fixation effect. After the plants grow, the sand carried by the wind will settle in the plant bushes, making the sand dunes gradually pile up. At the same time, the plants will also drill out from the new sand surface and continue to grow upward. The sand dunes are constantly piled up in the plant bushes, thus forming scrub dunes; and the method of artificial intervention is adopted to quickly construct sand dunes, and quickly make plants grow and cover the surface of the sand dunes, which has a positive effect on the formation and stability of scrub dunes.

[0014] 2. The dune construction device of the present invention adopts a method of combining fixed piles with coarse mesh groups and fine mesh groups, which can effectively accumulate in the enclosure to form stable sand dunes, and is conducive to planting plants in the sand dunes. The fixed piles and the enclosure will not affect the growth of plants; the fixed piles are provided with foldable and unfoldable handles, which are convenient for inserting the fixed piles into the sand. The first hook ring and the second hook ring provided on the fixed piles are conducive to fixing the enclosure on the fixed piles with fixing parts, so as to prevent the enclosure from being peeled off from the fixed piles by wind or waves; on the side close to the ocean A coarse mesh group is set up to filter the sand carried by the wind or waves, allowing the sand to enter the enclosure and blocking stones or other debris outside. The stones blocked outside the coarse mesh group also help to improve the stability of the device during long-term accumulation. A fine mesh group is set up on the side away from the ocean to prevent the sand in the enclosure from being blown away by the wind or carried away by the waves, which is conducive to the accumulation of sand dunes. When the accumulation height of the sand dunes exceeds the enclosure, it can continue to expand outward until the device is wrapped inside; and the sand dunes are arranged in a plum blossom shape, which is conducive to weakening the energy of the waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a structural schematic diagram of a method for constructing coastal plant dunes of the present invention.

[0017] Figure 2 It is a schematic diagram of sand dune distribution of a method for constructing coastal plant sand dunes of the present invention.

[0018] Figure 3 It is a schematic diagram of the early stage of sand dune accumulation in a method for constructing coastal plant dunes of the present invention.

[0019] Figure 4 It is a schematic diagram of the middle stage of sand dune accumulation of a method for constructing coastal plant dunes of the present invention.

[0020] Figure 5 It is a schematic diagram of the late stage of sand dune accumulation in a method for constructing coastal plant dunes according to the present invention.

[0021] Figure 6 It is a schematic diagram of a sand dune construction device of a method for constructing coastal plant sand dunes of the present invention.

[0022] Figure 7 It is a schematic diagram of a fixed pile structure of a method for constructing coastal plant dunes of the present invention.

[0023] Figure 8 It is a schematic cross-sectional view of a fixed pile structure of a method for constructing a coastal plant sand dune according to the present invention.

[0024] Fig. 9 It is a schematic diagram of the use status of fixed piles in a method for constructing coastal plant sand dunes of the present invention.

[0025] Fig.10 This is a schematic diagram of the connection state of fixed piles in a method for constructing a coastal plant dune according to the present invention. Figure 1 .

[0026] Fig.11 This is a schematic diagram of the connection state of fixed piles in a method for constructing a coastal plant dune according to the present invention. Figure 2 .

[0027] In the figure: 1-fixed pile, 11-main body, 111-drill bit, 112-handle groove, 12-mesh, 13-first hook ring, 14-second hook ring, 15-handle, 2-coarse mesh group, 21-first coarse mesh, 22-second coarse mesh, 23-third coarse mesh, 3-fine mesh group, 31-first fine mesh, 32-second fine mesh, 4-fixing piece group, 41-first fixing piece, 42-second fixing piece. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0030] Reference Figure 1-5 As shown, a method for constructing a coastal plant dune comprises: A plurality of dune protection belts are arranged on the beach in the middle and upper part of the high tide zone or the supratidal zone, wherein the dune protection belts include an outer layer close to the sea and an inner layer close to the coast, and an accumulation area formed by the outer layer and the inner layer; The sand passes through the outer layer and enters the accumulation area until a sand dune of target diameter and target height is formed in the accumulation area. According to the seawater salinity in the area where the sand dunes are located and the elevation of the sand dunes, at least one type of vegetation is planted on the sand dunes according to the salt tolerance of the plants to form grass or shrub dunes. The selected plants have the ability to tolerate salt, fix sand and withstand sand burial, can promote the sedimentation of sand carried by wind or seawater, and can continuously accumulate sand dunes as the vegetation grows. Plant planting is mainly bagged seedlings, and cutting seedlings can also be planted in the rainy season, combined with the method of sowing seeds; Among them, the position of the dune protection belt in the high tide zone is pi=L+(HL)×0.6; the position of the dune protection belt in the supratidal zone is ps=H+0.5×D; L is the height of the average low tide high tide line, which refers to the highest value that seawater can reach under normal weather conditions, H is the height of the average high tide line, which refers to the highest value that seawater can reach under extreme weather conditions, and (HL) represents the height range of the coastal high tide zone; the protection belt is placed at 60% of the total height of the high tide zone to avoid the protection belt being set too low to reduce the situation of being completely submerged by seawater, but it cannot be set too close to the supratidal zone to ensure that there is enough space to intercept sand. H+0.5×D refers to the space above the average high tide line that is half the expected height of the dunes, ensuring that the protection belt is above the high tide line, reserving enough space for the growth of dunes, and allowing the dunes formed subsequently to effectively weaken the waves.

[0031] The spacing of dune protection belts is S=W×0.75, where W is the expected width of the dune bottom; the height of the dune protection belt is Ha=0.3×D, where D is the expected maximum height of the dune; the number of dune protection belts N=coastline length / (W+S), where coastline length refers to the total length of the coast to be protected, and (W+S) is the space occupied by each dune protection belt. The spacing of dune protection belts is set to 75% of the expected dune width. Since the dune protection belts are arranged in a plum blossom shape on the beach, there will be overlapping parts between the dune protection belts to enhance the effect of capturing sand and reserve a certain amount of space for the natural development and expansion of dunes. Setting the height of the protection belt to 30% of the expected dune height is conducive to the initial formation of dunes, and the dunes formed are stable and not easily destroyed by wind or sea water, which is conducive to the subsequent growth of dunes.

[0032] Furthermore, the present invention first determines the average high tide line H and the average low tide line L of the beach area where the sand dunes are to be constructed, and selects the type of vegetation to be planted according to the salinity of the beach.

[0033] Furthermore, a plurality of dune protection belts are set up along the supratidal zone or high tide zone of the beach. The plurality of dune protection belts are generally arranged in a plum blossom shape along the supratidal zone or along the middle and upper part of the high tide zone of the beach. The dune protection belts are combined with an outer layer close to the sea and an inner layer close to the coast to form circular, semicircular and crescent-shaped docking areas. The outer layer of the dune protection belt is used to allow sand in the wind or sea water to enter the accumulation area. Therefore, the outer layer needs to be set in the windward place, and the inner layer is set in the upwind place to retain the sand in the accumulation area. Sand dunes are gradually accumulated in the dune protection belt. Planting vegetation in the dune protection belt is conducive to the early growth of vegetation, so that the vegetation can take root in the dunes and is not easily washed away by wind or sea water. Moreover, more sand can be deposited with the growth of vegetation, and the area and height of the dunes are continuously expanded, thereby achieving better wave breaking effect.

[0034] Furthermore, due to the high and low tides of the sea, in order to prevent the sand dunes from being repeatedly washed away by the sea water during the accumulation process, which would prevent the sand from accumulating, statistics were collected on the high tide values ​​of the sea area over the years in normal sea water to obtain the average high tide line H and the average low tide line L of the sea area. Based on this, the dune protection zone in the high tide zone is set at pi=L+(HL)×0.6, that is, the dune protection zone is set at 60% of the total height of the high tide zone, which is conducive to the accumulation of sand and reduces the inability of sand dunes to accumulate and form due to being submerged by sea water. In addition, the dune protection zone can be properly infiltrated by sea water, which can make the sand more stable and enable the dunes to form faster.

[0035] Furthermore, considering that the sea tide will be higher than the average high tide line during storms or extreme tides, the high tide values ​​of the sea water in this sea area under extreme weather conditions over the years were statistically analyzed to obtain the average high tide line height H of this sea area. Based on this, the dune protection belt in the supratidal zone is set at ps=H+0.5×D, that is, the dune protection belt is set above the average high tide line and half the expected dune height, to ensure that the sand dunes can still play a role in weakening the waves under extreme conditions and fully resist ocean dynamic erosion.

[0036] Furthermore, the spacing between each dune protection belt is S=W×0.75, and the height of the dune protection belt is Ha=0.3×D. The spacing of the dune protection belts is set to 75% of the expected dune width, and the multiple dune protection belts are generally arranged in a plum blossom shape along the supratidal zone of the beach or along the middle and upper part of the high tide zone. Therefore, there will be overlapping parts between the dune protection belts, which is conducive to the capture of sand and the production and expansion of dunes. As the dunes expand, adjacent dunes can be connected together to form a dune belt. Setting the height of the protection belt to 30% of the expected dune height is conducive to the initial formation of dunes and the growth of planted vegetation. When the dune accumulation height in the dune protection belt reaches 1 / 2Ha, vegetation is planted on the dunes and watered appropriately. The growth of vegetation is conducive to the sedimentation of sand. At this time, the sand particles covering the surface of the vegetation are smaller, which is conducive to the vegetation to drill out of the sand and continue to grow after being buried in the sand until the height of the dune reaches the height of the dune protection belt. After that, the sand will continue to accumulate behind the inner layer to expand the range of the dune, while the outer layer of the dune protection belt is deposited with materials that cannot pass through the outer layer. However, through the expansion of the growth area of ​​vegetation, sand can also be accumulated outside the outer layer.

[0037] Furthermore, plants with strong salt tolerance are mainly planted on the sand dunes. Coastal herbaceous plants are planted on the side of the sand dunes close to the outer layer, and salt-alkali tolerant shrubs are planted on the side of the sand dunes close to the inner layer; the coastal herbaceous plants are one or more of seahorse teeth, saddle vine, seaside evening primrose, haloth chrysanthemum, dogtooth grass, and salt-field shrew tail millet, and the salt-alkali tolerant shrubs are one or more of bitter gourd, single-leaf vitex, thousand-headed casuarina, and grass pittosporum; a single plant can be planted on the sand dunes, or a combination of multiple plants can be planted, and the plant combination needs to consider its ecological function and landscape value. The plant species and configuration patterns suitable for the restoration of backshore sand land in my country refer to Appendix A and Appendix C of "Technical Methods for Vegetation Restoration of Backshore Sand Land on Beaches" (HY / T 0304-2021). Common plant combinations include: single-leaf vitex, saddle vine, bitter gourd, single-leaf vitex, seahorse teeth, saddle vine, etc.

[0038] Furthermore, the beach area between the average neap high tide line and the average spring high tide line is often flooded by sea water, so general plants cannot grow and the sand is highly mobile. Therefore, it is necessary to first build a dune protection belt to form sand dunes of a certain height and range. After the prototype of the sand dune is formed, seahorses with strong salt tolerance are planted on the upper line of the sand dunes. As the seahorses grow, the sand dunes will gradually expand and increase. After the upper part of the sand dunes is higher than the average spring high tide line, plants with strong salt tolerance, such as simple-leaved vitex and saddle vine, are planted on the surface of the sand dunes to further promote the sedimentation of sand and the expansion and stability of the sand dunes.

[0039] The beach area above the average high tide line and between the coast is generally not flooded by sea water, but it is flooded by sea water during extreme weather such as typhoons. Therefore, the sand in this area is relatively dry and easily blown away by the wind. Therefore, there are two ways to construct this area: one is to first build a sand dune protection belt and then plant plants. There are many types of plants to choose from, such as simple-leaved vitex, bitter vine, saddle vine, seahorse teeth, and thorn. Generally, a combination of shrubs and vines or herbaceous plants is adopted. Shrubs are not easily buried by sand during summer typhoons or winter gales, and some plants can still maintain growth under extreme weather conditions. Vines or herbaceous plants have a large coverage rate and are usually more effective in promoting sand sedimentation and reducing sand loss. The combination of the two has a better effect on the formation and stabilization of sand dunes. Another method is to plant shrubs of a certain height first, use plants to block sand and gradually accumulate to form sand dunes. On the side of the sand dune close to the average high tide line, single-leaf vitex with strong salt tolerance is given priority. On the side close to the coast, single-leaf vitex and bitter lily can be planted. When the height of the sand dune reaches 50 cm, vines or herbaceous plants such as saddle vine, thorn, and seahorse teeth are further planted. Seahorse teeth are mainly planted on the side close to the ocean, and saddle vine and thorn are mainly planted on the side close to the land. Planting vines and herbaceous plants increases the vegetation coverage rate on the surface of the dune, promotes the expansion of the sand dunes and reduces sand loss.

[0040] Further, refer to Figure 6-11 As shown, the dune protection belt of the present invention comprises: a fixing pile 1, a coarse mesh group 2, a fine mesh group 3 and a fixing member group 4.

[0041] The fixed piles 1 are fixed on the beach, the coarse mesh group 2 is inserted between the adjacent multiple fixed piles 1 and is arranged on the side close to the ocean, and the coarse mesh group 2 constitutes the outer layer of the sand dune protection belt; the fine mesh group 3 is inserted between the adjacent multiple fixed piles 1 and is arranged on the side far away from the ocean, and the fine mesh group 3 constitutes the inner layer of the sand dune protection belt; the coarse mesh group 2 and the fine mesh group 3 are combined to form a fence of the sand dune protection belt; a fixing part group 4 is provided between the fixed piles 1 and the coarse mesh group 2, and between the fixed piles 1 and the fine mesh group 3, and the coarse mesh group 2 and the fine mesh group 3 are combined to form an accumulation area for the formation of sand dunes; by combining the fixed piles 1 with the coarse mesh group 2 and the fine mesh group 3, stable sand dunes can be effectively accumulated in the fence, and it is beneficial to plant plants in the sand dunes.

[0042] Furthermore, in order to fix the device on the beach and prevent it from being blown by the wind or knocked down by the waves, a fixing pile 1 is provided, which includes: a main body 11, a mesh 12, a first hook ring 13, a second hook ring 14 and a handle 15; the main body 11 is arranged in a columnar shape, a drill bit 111 is arranged at one end of the main body 11, and a handle groove 112 is opened at the other end of the main body 11, and two sets of handles 15 that rotate relative to each other are arranged in the handle groove 112. When the fixing pile 1 is not in use, the handles 15 are folded and stored in the handle groove 112. When the fixing pile 1 is in use, the two handles 15 are relatively rotated so that the handles 15 are unfolded to a horizontal state, which is convenient for people to hold the fixing pile 1 Inserted into the beach; a mesh hole 12 for the seine to pass through is axially penetrated on the main body 11, and a plurality of groups of first hook rings 13 are relatively arranged near the mesh hole 12 on the main body 11. In this embodiment, the first hook rings 13 are arranged at the short sides of the mesh hole 12 on both sides, and a group of first hook rings 13 are arranged at the two opening ends of the mesh hole 12; a plurality of second hook rings 14 are evenly arranged along the axial direction on the side wall of the main body 11, and the second hook rings 14 are arranged at the same height as the mesh hole 12. In this embodiment, three second hook rings 14 are arranged at equal intervals, and three second hook rings 14 are also arranged at the corresponding positions on the other side of the main body 11.

[0043] Furthermore, in order to allow sand outside the fence to enter the fence and block stones and debris, a coarse mesh group 2 is inserted between the multiple fixed piles 1, and the coarse mesh group 2 is set on the side close to the ocean. Wind and waves will first pass through the coarse mesh group 2 and then enter the fence and finally reach the fine mesh group 3. The sand carried by the wind and waves will pass through the mesh holes on the coarse mesh group 2 and enter the fence, and block stones and debris outside the coarse mesh group 2. The stones and debris outside the net are deposited in the process to strengthen the stability of the device; the coarse mesh group 2 includes: a first coarse mesh 21, a second coarse mesh 22 and a third coarse mesh 23, the first coarse mesh 2 The upper end of the coarse net 1 is connected to the lower end of the second coarse net 22, and the upper end of the second coarse net 22 is connected to the lower end of the third coarse net 23; the mesh number of the first coarse net 21 is 20-30 meshes, the mesh number of the second coarse net 22 is 30-40 meshes, and the mesh number of the third coarse net 23 is 40-50 meshes, so that the finally accumulated sand dunes are divided into three layers, and the bottom layer has sand of different particle sizes, which is conducive to the growth of the roots of the planted plants and enables the plants to grow stably on the sand dunes. The particle size of the sand is smaller as it goes up, which is conducive to the plants to quickly drill out from the sand after being buried and continue to fix the sand.

[0044] Furthermore, in order to prevent the sand entering the purse net from being carried away by the wind and waves, a fine mesh group 3 is provided, and the fine mesh group 3 is arranged on the side away from the ocean. After entering the purse net, the sand will be blocked in front of the net by the fine mesh group 3 and will first accumulate in front of the net; the fine mesh group includes: a first fine mesh 31 and a second fine mesh 32, the upper end of the first fine mesh 31 is connected to the lower end of the second fine mesh 32, the mesh number of the first fine mesh 31 is 50-60 meshes, and the mesh number of the second fine mesh 32 is 60-70 meshes, which is conducive to blocking most of the sand.

[0045] Furthermore, in order to fix the coarse mesh group 2 and the fine mesh group 3 on the fixed pile 1, a fixing member group 4 is provided, and the fixing member group 4 includes: a first fixing member 41 and a second fixing member 42. The first fixing member 41 is connected to the first hook ring 13 to make the coarse mesh group 2 and the fine mesh group 3 in a straightened state, which is conducive to better blocking sand. The first fixing member 41 can be a double-headed hook or a rope; the second fixing member 42 is connected to the second hook ring 14 to facilitate the fixation of the coarse mesh group 2 and the fine mesh group 3, and prevent the coarse mesh group 2 and the fine mesh group 3 from being peeled off from the fixed pile 1 by wind or waves. Figure 9-11 As shown, there are three different layout modes of the present invention, namely circular, crescent and semicircular, which can form dome-shaped dunes and crescent-shaped dunes, etc., and the device is arranged in the middle and upper part of the high tide zone or the supratidal zone of the beach. The sand dunes are generally arranged in a plum blossom shape along the middle and upper part of the high tide zone or the supratidal zone of the beach, and the elevation of the bottom of the sand dune is near or above the high tide line, and the elevation of the top of the sand dune is higher than the high tide line of the spring tide; the shrub dune finally formed is conducive to the sedimentation of sand, can weaken the energy of waves, and can play a better bank protection effect.

[0046] Further, the specific implementation mode of the present invention is: If seahorse teeth, saddle vine and other plants are planted, the dune protection belt should be enclosed in a circular shape with a diameter of 1 to 2 meters and a height of 50 to 100 cm. Plants should be planted when the height of the sand dunes reaches 30 to 50 cm. The plant seedlings used should be bagged seedlings. The length of seahorse teeth seedlings is 20 to 30 cm, and the length of saddle vine seedlings is 50 to 80 cm. The planting density should be controlled at 25 plants / m 2 .

[0047] If plants such as simple-leaved vine and bitter vine are planted, the shape of the dune protection belt can be circular, crescent-shaped, strip-shaped, etc. If it is set as a circular dune, the plants planted on the dune can be arranged in a circular, square or hexagonal shape, and the diameter of the planting area is set at 2-5m; if it is set as a crescent-shaped dune, the plants planted on the dune can be arranged in an arc or half-moon shape, and the diameter of the planting area is set at 3-8m; if it is set as a strip-shaped dune, the plants planted on the dune can be arranged in a rectangular shape, and the length is set at 8-15m and the width is 3-8m. Strip-shaped dunes are mainly set on the side close to the land. Simple-leaved vine and bitter vine are mainly bagged seedlings. Bare-root seedlings can also be used for planting during rainy periods. The height is 30-50cm, and the planting density is controlled at 9 plants / m 2 .

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for constructing coastal plant dunes, characterized in that: include: A plurality of dune protection belts are arranged on the beach in the middle and upper part of the high tide zone or the supratidal zone, wherein the protection belts include an outer layer close to the sea and an inner layer close to the coast, and an accumulation area formed by the outer layer and the inner layer; The sand passes through the outer layer and enters the accumulation area until a sand dune of a target diameter and a target height is formed in the accumulation area, and at least two belts of vegetation are planted on the sand dune from sea to land according to the salt tolerance level to form a shrub dune, wherein the shrub dune can settle the sand carried by the wind or sea water and can continuously accumulate the sand dune as the vegetation is generated; The spacing of the dune protection belts is S=W×0.75, where W is the desired width of the dune bottom; the height of the dune protection belt Ha=0.3×D, where D is the desired maximum height of the dune; the number of dune protection belts N=coastline length / (W+S), where (W+S) is the space occupied by each dune protection belt; The position of the dune protection zone in the high tide zone is pi=L+(HL)×0.6; the position of the dune protection zone in the supratidal zone is ps=H+0.5×D; L is the average height of the high tide line of neap tide, H is the average height of the high tide line of spring tide, and (HL) is the height range of the coastal high tide zone.

2. The method for constructing a coastal plant dune according to claim 1, characterized in that: A plurality of the dune protection belts are arranged in a plum blossom shape on the beach.

3. The method for constructing a coastal plant dune according to claim 1, characterized in that: The dune protection belt comprises: a plurality of fixed piles (1), a coarse mesh group (2), a fine mesh group (3) and a fixing member group (4); the fixed piles (1) are fixed on the beach; the coarse mesh group (2) is arranged on the fixed piles (1) to form the outer layer; and the fine mesh group (3) is arranged on the fixed piles (1) to form the inner layer.

4. The method for constructing a coastal plant dune according to claim 3, characterized in that: The coarse mesh group (2) is provided with a third coarse mesh (23), a second coarse mesh (22) and a first coarse mesh (21) in order from top to bottom.

5. The method for constructing a coastal plant dune according to claim 4, characterized in that: The mesh size of the third coarse net (23) is 40-50 meshes, the mesh size of the second coarse net (22) is 30-40 meshes, and the mesh size of the first coarse net (21) is 20-30 meshes.

6. The method for constructing a coastal plant dune according to claim 3, characterized in that: The fine mesh group (3) is provided with a second fine mesh (32) and a first fine mesh (31) in sequence from top to bottom.

7. The method for constructing a coastal plant dune according to claim 6, characterized in that: The mesh size of the second fine net (32) is between 50 and 60 meshes, and the mesh size of the first fine net (31) is between 60 and 70 meshes.

8. The method for constructing coastal plant dunes according to claim 1, characterized in that: The sand dune is planted with coastal herbs on a side close to the outer layer, and the sand dune is planted with salt-alkali tolerant shrubs on a side close to the inner layer.

9. The method for constructing coastal plant dunes according to claim 8, characterized in that: The coastal herbaceous plants are one or more of seahorse, saddle vine, seaside evening primrose, hawthorn, dogtooth grass, and salt shrew tail millet; the salt-alkali tolerant shrubs are one or more of bitter orange, simple vitex, thousand-headed casuarina, and grass seahorse.

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