Permanent and temporary combined ecological wave-dissipating belt structure and construction method thereof

Abstract

The present application relates to the technical field of lake and reservoir ecological restoration engineering, and discloses a permanent and temporary combined ecological wave-damping belt structure and a construction method thereof, which comprises a sub-dyke arranged along the side of an outer lake, a main dyke located on the lake side of the sub-dyke, and an ecological planting area arranged on the lake side of the main dyke, wherein the main dyke and the sub-dyke jointly form a water-retaining cofferdam during construction; the main dyke comprises a removable upper dyke body which is removed after the vegetation in the ecological planting area is stabilized, and the removed materials are reconfigured on the remaining structure of the sub-dyke or the main dyke. The present application uses ripraps, lake excavation silt and earthwork, stone cage net mat, geotextile, aquatic plants and the like to construct an ecological wave-damping belt in the lake area, adopts a permanent and temporary combined construction scheme, uses local materials, has no external soil disposal, is low in carbon emission, energy-saving and emission-reducing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lake and reservoir ecological restoration engineering, in particular to a permanent-temporary combined ecological wave-dissipation belt structure and a construction method thereof. BACKGROUND

[0002] In a large water area environment such as a lake or a reservoir, due to the open water surface, the wind wave effect is significant, and the erosion problem of the bank slope and the beach surface is particularly prominent, especially in the region of the main wind direction, the structure is often damaged due to wind wave scouring, and at the same time, the vegetation in this region is difficult to survive and has a low survival rate. In order to reduce the harm caused by wind waves, it is necessary to arrange wave-dissipation facilities in the lake area.

[0003] From the perspective of ecology and landscape demand, the ecological wave-dissipation belt combined with the underwater dike and the vegetation is a relatively ideal choice, which can balance the functional and ecological landscape values. However, when the wave-dissipation belt is constructed in the lake area, a temporary construction cofferdam must be built first. In view of the characteristics of large wind waves in the large water area of the lake, the most commonly used cofferdam type is a double-row steel sheet pile with soil filling in the middle. However, this type has obvious drawbacks: the steel sheet pile construction operation in the water area not only consumes a large amount of time and manpower, but also has a high construction cost; at the same time, after the completion of the main dike project, the steel sheet pile cofferdam needs to be removed, which further increases the workload and cost of construction, and the removal process may generate waste, which has a certain impact on the environment.

[0004] Therefore, how to solve the problem of wind wave erosion of the bank slope and the beach surface of the lake and reservoir, while overcoming the time-consuming, labor-intensive, high-cost and possible environmental problems in the process of constructing and removing the temporary cofferdam, has become a technical problem to be solved in the field. SUMMARY

[0005] Therefore, the present application provides a permanent-temporary combined ecological wave-dissipation belt structure and a construction method thereof to solve the above problems.

[0006] In a first aspect, the present application provides a permanent-temporary combined ecological wave-dissipation belt structure, comprising:

[0007] a sub-dike arranged along the outer lake side;

[0008] a main dike located on the inner lake side of the sub-dike, which together with the sub-dike forms a water-retaining cofferdam during construction;

[0009] an ecological planting area provided on the inner lake side of the main dike;

[0010] wherein the main dike comprises a removable upper dike body, which is removed after the vegetation in the ecological planting area is stabilized, and the removed material is reconfigured on the sub-dike or the remaining structure of the main dike.

[0011] In the structure, the cofferdam formed by the sub-dyke and the main dyke can effectively resist the wind waves and water flow from the outer lake, providing a safe and stable working environment for the construction of the topography shaping and plant planting of the ecological planting area, and ensuring the smooth progress of the construction. The sub-dyke continuously plays a role in blocking the wind waves from the outer lake, reducing the wave height and the wind wave force; after the vegetation in the ecological planting area stabilizes, it cooperates with the sub-dyke and the remaining structure of the main dyke to form a multi-level wave dissipation system, significantly reducing the erosion risk of the wind waves to the bank slope and the beach surface, and providing diverse habitats for plants and animals, thereby improving the stability of the ecological system. The materials removed from the upper part of the main dyke are reused, avoiding material waste and waste disposal, reducing construction costs and environmental impact, and achieving efficient resource utilization and low-carbon environmental protection goals.

[0012] In an optional embodiment, the sub-dyke comprises an underwater riprap body and a dry masonry body exposed to the water surface, and the top surface of the dry masonry body forms a construction channel with a top elevation level with the design normal water level of the lake area.

[0013] The underwater riprap body of the sub-dyke is constructed by underwater riprap construction method, and the top elevation is level with the construction low water level H1, which can form a stable foundation underwater and preliminarily block the wind waves from the outer lake, providing a foundation guarantee for subsequent construction. The dry masonry body exposed to the water surface is constructed by block stone dry masonry, and the surface is rationally laid and flat, which not only further enhances the overall structural strength of the sub-dyke, but also forms a construction channel with a width of not less than 3.0m on the top surface, which can meet the transportation needs of personnel, equipment and materials during construction, and create convenient conditions for the construction of the main dyke and the ecological planting area on the inner lake side.

[0014] Meanwhile, the top elevation of the dry masonry body is level with the design normal water level H2 of the lake area, which makes the dry masonry body fully play a water blocking role when the lake area is at the design normal water level, and together with the underwater riprap body forms an effective barrier to reduce the impact of wind waves from the outer lake on the construction area on the inner lake side, and ensures the smooth progress of the construction. In addition, this structural design also lays a foundation for the subsequent temporary cofferdam formed by the main dyke, which embodies the characteristics of the function connection between temporary facilities and permanent engineering in the permanent and temporary combination scheme.

[0015] In an optional embodiment, the main dyke comprises:

[0016] a lower dyke body filled with lake area excavation materials, with a top elevation not higher than the design normal water level;

[0017] an upper dyke body covered on the lower dyke body, with an anti-erosion layer on the outer lake side and a top elevation higher than the operating high water level.

[0018] In an optional embodiment, the anti-erosion layer comprises a stone cage net layer and a geotextile filter layer laid below it.

[0019] In an alternative embodiment, the ecological planting area comprises a gradient planting platform, the elevation configuration of which meets the partition planting requirements of emergent plants and submerged plants.

[0020] In an alternative embodiment, the top elevation of the planting platform is 0.2m lower than the design normal water level.

[0021] In a second aspect, the present application further provides a construction method using the permanent-temporary combined ecological wave-dissipating belt structure, comprising the following steps:

[0022] Constructing a sub-dike, forming a wave-dissipating base through underwater dumping of stones, and forming a top structure with a construction passage function through dry masonry of stones;

[0023] Constructing a main dike, filling the lower dike body of the main dike with lake excavation materials under the protection of the sub-dike, and constructing a removable upper dike body thereon;

[0024] Forming an ecological planting area, shaping a planting terrain under the dry land condition formed by the water retaining of the cofferdam, and planting aquatic plants;

[0025] After the vegetation is stabilized, removing the upper dike body of the main dike and reconfiguring the materials in the permanent structure.

[0026] In an alternative embodiment, in the step of forming an ecological planting area, shaping a planting terrain under the dry land condition formed by the water retaining of the cofferdam, and planting aquatic plants:

[0027] The stones with a particle size greater than 20cm are scattered on the top of the sub-dike;

[0028] The crushed materials and geotechnical materials with a particle size less than 20cm are laid on the surface of the lower dike body of the main dike.

[0029] In an alternative embodiment, in the step of constructing a main dike, filling the lower dike body of the main dike with lake excavation materials under the protection of the sub-dike, and constructing a removable upper dike body thereon, the lower dike body of the main dike is formed by dumping lake earthwork with a dredger, and the slope ratio range is 1:3-1:5.

[0030] In an alternative embodiment, in the step of forming an ecological planting area, shaping a planting terrain under the dry land condition formed by the water retaining of the cofferdam, and planting aquatic plants, the aquatic plants need to undergo a maintenance period of not less than 1 year after planting, until the root system is stable and can resist wind and wave erosion. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0032] Figure 1 A plan view of a permanent and temporary combined ecological wave dissipation belt structure according to an embodiment of the present application;

[0033] Figure 2 A cross-sectional view of a permanent and temporary combined ecological wave dissipation belt structure according to an embodiment of the present application (first stage);

[0034] Figure 3 A cross-sectional view of a permanent and temporary combined ecological wave dissipation belt structure according to an embodiment of the present application (second stage);

[0035] Figure 4 A cross-sectional view of a permanent and temporary combined ecological wave dissipation belt structure according to an embodiment of the present application (third stage).

[0036] Explanation of reference signs:

[0037] 1, sub-dyke; 11, underwater riprap; 12, dry masonry;

[0038] 2, main dyke; 21, lower dyke body; 22, upper dyke body; 23, gabion mat; 24, geotextile;

[0039] 3, ecological planting area; 31, topography shaping; 32, emergent and floating leaf plants; 33, submerged plants. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0041] In a large water area environment such as a lake or a reservoir, due to the open water surface, the wind wave effect is significant, and the erosion problem of the bank slope and the beach surface is particularly prominent, especially the bank slope in the main wind direction region, which is often damaged due to wind wave scouring, and at the same time, the vegetation in this region is difficult to survive and has a low survival rate. In order to reduce the harm caused by the wind wave, it is necessary to arrange wave dissipation facilities in the lake area.

[0042] From the ecological and landscape needs, the ecological wave dissipation belt combined with underwater submerged dike and vegetation is an ideal choice, which can balance the functional and ecological landscape value. However, when the wave dissipation belt is constructed in the lake area, a temporary construction cofferdam must be built. In view of the characteristics of large water area and large wind wave in the lake area, the most commonly used cofferdam type is the double-row steel sheet pile structure filled with soil in the middle. However, this type has obvious disadvantages: the construction of steel sheet pile in the water area not only consumes a lot of time and manpower, but also has high construction cost; at the same time, after the completion of the main dike project, the steel sheet pile cofferdam needs to be removed, which further increases the workload and cost of construction, and the removal process may produce waste slag and cause certain environmental impact.

[0043] Therefore, how to solve the problem of wind wave erosion on the beach of the lake bank slope, while overcoming the problems of time-consuming, labor-intensive, high cost and possible environmental impact in the process of temporary cofferdam construction and removal, has become a technical problem to be solved in the field.

[0044] The embodiments of the present application will be described below in combination with Figures 1 to 4 .

[0045] According to the embodiments of the present application, on the one hand, a permanent and temporary combined ecological wave dissipation belt structure is provided, which comprises a sub-dike 1 arranged along the outer lake side, a main dike 2 located on the inner lake side of the sub-dike 1, and an ecological planting area 3 arranged on the inner lake side of the main dike 2, the main dike 2 and the sub-dike 1 jointly constitute a water retaining cofferdam during construction; wherein the main dike 2 comprises a removable upper dike body 22, which is removed after the vegetation in the ecological planting area 3 is stabilized, and the removed materials are reconfigured on the sub-dike 1 or the remaining structure of the main dike 2.

[0046] The permanent and temporary combined ecological wave dissipation belt structure can efficiently play the water retaining and wave preventing function during construction and form a stable ecological wave dissipation system in the later period through the synergistic effect of the sub-dike 1, the main dike 2 and the ecological planting area 3. Specifically, the sub-dike 1 is arranged in the outermost circle and blocks the wind wave on the outer lake side to create a stable environment for the construction of the main dike 2; the main dike 2 is arranged close to the inner lake side of the sub-dike 1 and jointly constitutes a closed construction cofferdam with the sub-dike 1, which effectively blocks the water flow on the outer lake side and ensures that the construction of the ecological planting area 3 on the inner lake side can be carried out under dry land conditions. After the vegetation in the ecological planting area 3 is stabilized for at least one year, the removable upper dike body 22 of the main dike 2 is removed. The materials generated by the removal are not discarded, but are reconfigured according to the functional requirements, part of the materials are used for the sub-dike 1 to enhance the wave dissipation capacity of the sub-dike 1, and the other part is used for the remaining structure of the main dike 2 to further consolidate the stability of the main dike 2.

[0047] In the structure, the cofferdam formed by the sub-dyke 1 and the main dyke 2 can effectively resist the wind waves and water flow from the outer lake, and provide a safe and stable working environment for the topography shaping 31, plant planting and other construction links of the ecological planting area 3, and ensure the smooth progress of the construction. The sub-dyke 1 continuously plays a role in blocking the wind waves from the outer lake, reducing the wave height and reducing the wind wave force; after the vegetation in the ecological planting area 3 grows stably, it cooperates with the remaining structure of the sub-dyke 1 and the main dyke 2 to form a multi-level wave dissipation system, which significantly reduces the erosion risk of the wind waves to the bank slope and the beach surface, and at the same time provides diversified habitats for plants and animals, and improves the stability of the ecological system. The materials of the upper dyke body 22 of the main dyke 2 are reused, which avoids material waste and waste residue transportation, reduces construction cost and environmental impact, and realizes efficient use of resources and low-carbon environmental protection goals.

[0048] In one embodiment, the sub-dyke 1 includes an underwater riprap body 11 and a dry masonry body 12 exposed to the water surface, and the top surface of the dry masonry body 12 forms a construction channel, and the top elevation is flush with the design normal water level of the lake area.

[0049] In this embodiment, as shown in Figure 2 The underwater riprap body 11 of the sub-dyke 1 is constructed by underwater riprap construction, and the top elevation is flush with the construction low water level H1, which can form a stable foundation underwater and preliminarily block the wind waves from the outer lake, providing a foundation guarantee for subsequent construction. The dry masonry body 12 exposed to the water surface is constructed by block stone dry masonry, and the surface is smoothly laid and leveled, which not only further enhances the overall structural strength of the sub-dyke 1, but also forms a construction channel with a width of not less than 3.0m on the top surface, which can meet the needs of personnel, equipment and material transportation during construction, and create convenient conditions for the construction of the main dyke 2 and the ecological planting area 3 on the inner lake side.

[0050] At the same time, the top elevation of the dry masonry body 12 is flush with the design normal water level H2 of the lake area, which makes the dry masonry body 12 fully play a water blocking role when the lake area is at the design normal water level, and together with the underwater riprap body 11 forms an effective barrier to reduce the impact of wind waves from the outer lake on the construction area on the inner lake side, and ensure the smooth progress of the construction. In addition, this structural design also lays a foundation for the subsequent temporary cofferdam formed by cooperating with the main dyke 2, which embodies the characteristics of the function connection of temporary facilities and permanent engineering in the permanent and temporary combination scheme.

[0051] In one embodiment, the main dyke 2 includes a lower dyke body 21 filled with lake area excavation materials and an upper dyke body 22 overlaid on the lower dyke body 21, and the top elevation of the lower dyke body 21 is not higher than the design normal water level; the outer lake side of the upper dyke body 22 is provided with an erosion prevention layer, and the top elevation is higher than the operating high water level.

[0052] In this embodiment, the lower embankment 21 of the main embankment 2 is filled with lake excavation materials (mud and earthwork) through dredging ship water filling operations. This on-site material utilization method not only simplifies the construction process, shortens the construction period, and reduces the material transportation cost, but also meets the economic and applicable principles. The top elevation of the main embankment 2 is not higher than the design normal water level of the lake area, which can cooperate with the sub-embankment 1 to form an effective water retaining barrier, create dry land conditions for the construction work on the inner lake side, and ensure the smooth development of subsequent construction.

[0053] The upper embankment 22 covers the lower embankment 21 and is filled with plain soil and compacted. The top width of the upper embankment 22 is not less than 3.0m to ensure the stability of the structure. An erosion prevention layer is provided on the outer lake side of the upper embankment 22. The erosion prevention layer is composed of a gabion mesh mat 23 and a geotextile 24. The gabion mesh mat 23 has a thickness of 30cm and can directly resist the erosion and scour of the upper embankment 22 by wind and waves. The geotextile 24 is laid under the gabion mesh mat 23 and can further prevent water and soil loss of the upper embankment 22. Through double protection, the wind and wave erosion resistance of the main embankment 2 during construction and the vegetation maintenance period is enhanced.

[0054] As shown in a specific embodiment, Figure 3 the top elevation of the upper embankment 22 is 1m higher than the lake operation high water level. This design plays an important role in the vegetation maintenance stage of the ecological planting area 3 and can provide reliable shelter for the inner plants to avoid damage to the seedlings by wind and waves on the outer lake side, ensuring the stable growth of the vegetation and fully embodying the dual functions of the main embankment 2 in the "permanent and temporary combination" mode, which meets the water retaining and wave preventing requirements during the construction period and provides support for the construction of the later ecological system.

[0055] Further, the erosion prevention layer includes a gabion mesh layer and a geotextile filter layer laid thereunder.

[0056] In this embodiment, the erosion prevention layer on the outer lake side of the upper embankment 22 of the main embankment 2 is composed of a gabion mesh layer and a geotextile filter layer, which form a double protection system through synergistic effect, effectively ensuring the stability of the upper embankment 22.

[0057] The gabion mesh layer adopts a gabion mesh mat 23 with a thickness of 30cm, which forms a solid barrier through the close packing of block stones and directly resists the impact and scour of wind and waves on the outer lake side, reducing the erosion intensity of wind and waves on the embankment of the upper embankment 22 and providing hard core protection for the upper embankment 22.

[0058] The geotextile filter layer is laid under the gabion mesh layer, which mainly blocks the soil particles of the upper embankment 22 to prevent water and soil loss under the action of wind and waves or water seepage, avoiding the structure deformation or stability decrease of the upper embankment 22 due to soil loss.

[0059] The anti-erosion layer composed of the gabion mesh layer and the geotextile filter layer not only has the characteristics of strong anti-erosion ability of the gabion mesh mat 23, but also has the anti-seepage and filtration soil functions of the geotextile filter layer (geotextile 24), and comprehensively enhances the anti-erosion performance of the upper embankment 22 of the main embankment 2 during the construction period and the vegetation maintenance period, so as to ensure that the main embankment 2 can stably play the water-retaining and wave-preventing role, and provide reliable protection for the initial growth of the vegetation in the ecological planting area 3.

[0060] In one embodiment, the ecological planting area 3 comprises a gradient change planting platform, and the elevation configuration of the gradient change planting platform meets the partition planting requirements of emergent plants and submerged plants 33.

[0061] In this embodiment, the gradient change planting platform of the ecological planting area 3 is designed based on the growth requirements of different aquatic plants on water depth. In one specific embodiment as shown in the figure, the top elevation of the planting platform is 0.2 m lower than the design normal water level of the lake area. By shaping the terrain with alternating deep and shallow changes, the habitat conditions suitable for the partition growth of emergent plants and submerged plants 33 are formed. Figure 4

[0062] The emergent and floating leaf plants 32 are arranged in the shallow water area at the top of the planting platform, and the water depth here meets the growth characteristics that the roots are fixed to the bottom mud and the stems and leaves are out of the water surface; and the submerged plants 33 are distributed in the deep water area around the planting platform, and the water depth of this area meets the growth requirement that the whole plant is submerged in water.

[0063] The gradient change planting platform design not only realizes the scientific partition planting of emergent plants and submerged plants 33, but also creates diversified wetland habitats, which helps to improve the stability and biodiversity of the ecological system, and also enhances the wave dissipation capacity and landscape effect of the ecological planting area 3.

[0064] Further, the top elevation of the planting platform is 0.2 m lower than the design normal water level.

[0065] In this embodiment, the top elevation of the planting platform is 0.2 m lower than the design normal water level of the lake area, and this elevation setting precisely matches the growth habit of the emergent and floating leaf plants 32. The emergent and floating leaf plants 32 need to root in the moist bottom mud, and at the same time, part of the stems and leaves are out of the water surface or grow on the water surface, and the shallow water environment formed by the elevation of the planting platform can provide suitable water, light and substrate conditions for the normal growth and development of the emergent and floating leaf plants 32.

[0066] ​Meanwhile, the elevation design forms a water depth gradient with the surrounding area, so that the top of the planting platform and the surrounding deep water area form a habitat difference of alternating deep and shallow. This difference not only provides suitable growth space for emergent and floating leaf plants 32 and submerged plants 33 (distributed in the deep water area), realizes scientific zoned planting, but also further enriches the wetland habitat types of the ecological planting area 3, helps to improve the biodiversity of the region, and enhances the stability and wave dissipation function of the ecological system.

[0067] According to an embodiment of the present application, in another aspect, a construction method is also provided, which adopts the ecological wave dissipation belt structure combining permanent and temporary structures, and includes the following steps:

[0068] The sub-dike 1 is constructed by forming a wave dissipation base through underwater riprap and then forming a top structure with dry masonry which also functions as a construction channel;

[0069] In this step, the wave dissipation base (underwater riprap body 11) is first formed through underwater riprap operation, the top elevation of which is level with the low water level of the construction site, which can preliminarily block the wind waves from the outer lake side and provide a stable water environment for subsequent construction. Then, the top structure (dry masonry body 12) is formed on the upper part of the underwater riprap body 11 by dry masonry, the surface of which is smoothly laid and the top width of which is not less than 3.0 m, and the top elevation of which is level with the design normal water level of the lake area. This top structure not only enhances the overall wave blocking capacity of the sub-dike 1, but also directly serves as a construction channel to meet the transportation needs of personnel, equipment and materials during construction, thereby creating convenient conditions for the construction of the main dike 2 and the ecological planting area 3 on the inner lake side.

[0070] The main dike 2 is constructed, and under the protection of the sub-dike 1, the lower dike body 21 of the main dike 2 is filled with lake excavation materials, and the upper dike body 22 is constructed on it;

[0071] Specifically, under the protection of the sub-dike 1 which blocks the strong waves from the outer lake side, the construction of the main dike 2 can be carried out smoothly. First, the lower dike body 21 of the main dike 2 is filled with lake excavation materials (silt and earthwork) through the on-water throwing and filling operation of the dredging ship, and the top elevation of which is level with the sub-dike 1 (i.e. level with the design normal water level). As shown in a specific embodiment, Figure 3 As shown in a specific embodiment, the inner lake side upper section slope ratio is 1:5, which reduces the construction cost and shortens the construction period by using local materials; then the upper dike body 22 is constructed on the lower dike body 21, which is filled and compacted with plain soil, the top width of which is not less than 3.0 m, the inner and outer slope ratio is 1:2.5, the erosion prevention layer (stone mattress 23 + geotextile 24) is arranged on the outer lake side, and the top elevation is 1.0 m higher than the running high water level of the lake area. The main dike 2 and the sub-dike 1 jointly form a construction cofferdam, which effectively blocks the water flow, ensures that the subsequent construction on the inner lake side can be carried out under dry land conditions, and at the same time provides wave protection for the vegetation maintenance period of the ecological planting area 3.

[0072] forming the ecological planting area 3, shaping the planting terrain under the dry land condition formed by the cofferdam water retaining, and planting aquatic plants;

[0073] Specifically, under the dry land condition formed by the cofferdam water retaining formed by the main dike 2 and the sub-dike 1, the terrain of the ecological planting area 3 is shaped 31 (forming a planting platform), the top elevation of the planting platform is 0.2 m lower than the design normal water level of the lake area, and the deep and shallow habitats are created; then the emergent and floating leaf plants are planted 32 in the shallow water area on the top of the planting platform, and the submerged plants are planted 33 in the deep water area. This zoned planting method meets the growth needs of different aquatic plants, lays a foundation for the stable growth of vegetation, and also creates conditions for the subsequent formation of a diversified ecological wave dissipation system.

[0074] After the vegetation is stabilized, the upper dike body 22 of the main dike 2 is removed and the materials are reconfigured in the permanent structure.

[0075] Specifically, after the vegetation of the ecological planting area 3 is maintained for at least one year, it has rooted into the soil and can resist the influence of small wind waves. At this time, the upper dike body 22 of the main dike 2 is removed. The removed earthwork does not need to be transported outside and is directly backfilled in the lake area excavation area, reducing the cost and environmental impact of waste disposal; the block stones with a particle size of 20-30 cm in the gabion mat 23 are scattered on the top of the sub-dike 1, further enhancing the wave dissipation capacity of the sub-dike 1 and improving the landscape effect; the broken stones with a particle size of less than 20 cm and the geotextile 24 are laid on the inner lake side of the top of the lower dike body 21, serving as a beach stabilization function. The reconfiguration of materials realizes efficient use of resources, avoids waste, and at the same time completes the functional transformation from a temporary cofferdam to a permanent ecological wave dissipation belt, achieving the goal of permanent and temporary combination, low carbon and environmental protection.

[0076] In one embodiment, in the step of forming the ecological planting area 3, shaping the planting terrain under the dry land condition formed by the cofferdam water retaining, and planting aquatic plants:

[0077] The block stones with a particle size greater than 20 cm are scattered on the top of the sub-dike 1;

[0078] The broken materials with a particle size less than 20 cm and the geotextile are laid on the surface of the lower dike body 21 of the main dike 2.

[0079] When the ecological planting area 3 completes the shaping of the planting terrain 31 and the planting of aquatic plants under the dry land condition formed by the cofferdam water retaining, as the vegetation gradually grows and stabilizes, the materials produced when the upper dike body 22 of the main dike 2 is removed are fully reused. Among them, the block stones with a particle size greater than 20 cm are scattered on the top of the sub-dike 1. This arrangement not only further enhances the blocking and reducing capacity of the sub-dike 1 to wind waves, reducing the transmission of wind waves from the outer lake side to the inner lake side, but also improves the landscape effect of the sub-dike 1 through the natural arrangement of the block stones, making the structure and ecological landscape needs compatible.

[0080] The debris and earthwork material with particle size less than 20 cm are laid on the surface of the lower embankment 21 of the main embankment 2, especially in the area of the inner lake side. The debris can fill the gaps on the surface of the lower embankment 21, enhance the integrity and erosion resistance of the structure; the earthwork material plays the role of seepage prevention and soil filtration, effectively prevents the water and soil loss of the lower embankment 21 of the main embankment 2, and the two together play the effect of beach fixation and embankment protection, ensure the stability of the remaining structure of the main embankment 2, provide continuous safety guarantee for the ecological planting area 3, realize the efficient use of materials, avoid waste and external abandonment, and meet the construction concept of low carbon and environmental protection.

[0081] In one embodiment, the main embankment 2 is constructed, the lower embankment 21 of the main embankment 2 is filled with the lake area excavation material under the protection of the sub-embankment 1, and in the step of constructing the removable upper embankment 22 on the lower embankment 21, the lower embankment 21 of the main embankment 2 is formed by the dredging ship throwing filling the lake area earthwork in water, and the slope ratio range is 1:3-1:5.

[0082] In one embodiment, the ecological planting area 3 is formed, the planting terrain is shaped under the dry land condition formed by the cofferdam water retaining, and in the step of planting aquatic plants, the aquatic plants need to go through a maintenance period of not less than 1 year after planting, until the root system is stable and can resist wind wave erosion.

[0083] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A permanent and temporary combined ecological wave-dissipating belt structure, characterized in that, include: Sub-dikes arranged along the outer lake side (1); The main dike (2) located on the inner lake side of the sub-dike (1) together with the sub-dike (1) forms a water-retaining cofferdam during the construction period; An ecological planting area (3) is set up on the lake side inside the main dike (2); The main dike (2) includes a removable upper dike body (22), which is removed after the vegetation in the ecological planting area (3) is stabilized, and the removal materials are reconfigured on the remaining structure of the sub-dike (1) or the main dike (2). The sub-dike (1) includes an underwater riprap body (11) and a dry masonry body (12) exposed above the water surface. The top surface of the dry masonry body (12) forms a construction passage, and its top elevation is level with the design normal water level of the lake area. The main dike (2) also includes: The lower embankment (21) constructed from excavated material from the lake area has a top elevation that is not higher than the design normal water level; The upper embankment (22) is laid on the lower embankment (21), and an anti-erosion layer is set on its outer lake side, with the top elevation higher than the operating high water level.

2. The ecological wave-dissipating belt structure combining permanent and temporary structures according to claim 1, characterized in that, The anti-erosion layer includes a gabion mesh layer and a geotextile filter layer laid underneath it.

3. The ecological wave-dissipating belt structure combining permanent and temporary structures according to claim 1, characterized in that, The ecological planting area (3) includes a planting platform with varying elevations, the elevation of which meets the requirements for the zonal planting of emergent and submerged plants (33).

4. The ecological wave-dissipating belt structure combining permanent and temporary structures according to claim 3, characterized in that, The top elevation of the planting platform is 0.2m lower than the design normal water level.

5. A construction method, employing the permanent-temporary combined ecological wave-dissipating belt structure as described in any one of claims 1-4, characterized in that, Includes the following steps: Construct a sub-dike (1), form a wave-dissipating base by underwater rock dumping, and then dry-lay boulders to form a top structure that also serves as a construction passage; Construct the main dike (2), and under the protection of the sub-dike (1), fill the lower part of the main dike (21) with lake excavation material, and construct the removable upper dike (22) on it. An ecological planting area (3) is formed, and a planting terrain is created under the dry land conditions formed by the embankment, and aquatic plants are planted; After the vegetation stabilizes, the upper part of the main dike (2) (22) is removed and its materials are reconfigured into the permanent structure.

6. The construction method according to claim 5, characterized in that, In the process of forming the ecological planting area (3), shaping the planting terrain under the dry land conditions formed by the cofferdam, and planting aquatic plants: Stones with a diameter greater than 20cm are scattered on the top of the sub-embankment (1); Crushed material and geotextile with a particle size of less than 20cm are laid on the surface of the lower part of the main dike (21).

7. The construction method according to claim 5, characterized in that, In the construction of the main dike (2), under the protection of the sub-dike (1), the lower part of the dike body (21) of the main dike (2) is filled with lake excavated material, and a removable upper dike body (22) is constructed on it. The lower part of the dike body (21) of the main dike (2) is formed by dumping lake soil on the water by a dredger, with a slope ratio ranging from 1:3 to 1:

5.

8. The construction method according to claim 5, characterized in that, In the process of forming an ecological planting area (3), the planting terrain is shaped under the dry conditions formed by the dike, and aquatic plants are planted. After the aquatic plants are planted, they need to undergo a maintenance period of no less than 1 year until the root system is stable and can resist wind and wave erosion.

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