A permeable ecological bank protection structure prepared in situ from polluted river sediment

Abstract

The present invention discloses an in-situ permeable ecological revetment structure prepared from polluted riverbed mud, comprising a base layer group, a seepage purification layer group, a bottom anti-seepage layer group, a polluted sediment main layer group, and an ecological planting layer group. The base layer group comprises a first revetment foundation, a second revetment foundation, a gravity retaining wall, and a riverbed slope protection. The seepage purification layer group is arranged on the gravity retaining wall. The seepage purification layer group comprises a permeable reaction wall, which is used to filter harmful substances in the accumulated water. The polluted sediment main layer group comprises multiple polluted sediment layers and multiple waste biomass material layers. The ecological planting layer group comprises ecological concrete, planting soil, and herbaceous plants. By adopting an in-situ treatment method to dispose of the polluted sediment in the river, utilizing the interception effect of the permeable reaction wall on pollutants and the purification effect of plants, the concentration of pollutants that seep into the river from the polluted sediment main structure can be effectively reduced, thereby realizing the in-situ resource utilization of the polluted riverbed mud.

Description

Technical Field

[0001] The present invention relates to the field of contaminated sediment restoration and river bank protection structure, and in particular to a permeable ecological bank protection structure prepared in situ from contaminated river sediment. Background Art

[0002] With the rapid development of urbanization and industrialization, the increasing population has led to an increase in domestic and industrial wastewater. This wastewater contains large amounts of pollutants such as organic matter, heavy metals, and nutrients, which are ultimately discharged into rivers, causing sediment pollution. Sediment pollution is a major cause of black and odorous water bodies and the degradation of ecological functions. River dredging is an important means of treating black and odorous water bodies, and the treatment and disposal of desilted sediment is a key factor restricting river dredging.

[0003] When the concentration of detected sediment pollutants exceeds the regional background value by two to three times, the river requires dredging. The dredged sediment is typically transported long distances to remote suburban areas for burial or drying. However, if the heavy metal content in the dredged sediment exceeds the standard, it is classified as hazardous waste and cannot be buried. Some dredged sediment that cannot be buried is dried and incinerated, while others is sintered into building materials for resource utilization. These methods can cause certain environmental pollution and have high transportation costs. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to propose an in-situ permeable ecological bank protection structure prepared from polluted river sediment.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A permeable ecological bank protection structure prepared in situ from polluted riverbed mud comprises a foundation group, a seepage purification layer group, a bottom anti-seepage layer group, a polluted sediment main layer group and an ecological planting layer group, the foundation group comprises a first bank protection foundation, a second bank protection foundation, a gravity retaining wall and a riverbed slope protection, the first bank protection foundation is arranged at the bottom of the riverbed and is arranged close to the edge of the riverbed, the first bank protection foundation has a first receiving surface, the first receiving surface is arranged in a horizontal direction, the second bank protection foundation is arranged adjacent to the first bank protection foundation and is arranged on a side away from the riverbed, the second bank protection foundation has a second receiving surface and a third receiving surface, the third receiving surface is arranged in a vertical direction, the height of the second receiving surface from the riverbed gradually decreases from the edge of the riverbed to the riverbed according to a preset gradient, the gravity retaining wall is arranged on the first receiving surface, the gravity retaining wall is also connected to the third receiving surface, the riverbed slope protection is arranged on the first receiving surface and is adjacent to the gravity retaining wall, and the riverbed slope protection is inclined at 45-60 degrees toward the riverbed;

[0007] The seepage purification layer group is arranged on the gravity retaining wall, and the seepage purification layer group includes a permeable reaction wall, which is used to filter harmful substances in the accumulated water; the bottom anti-seepage layer group is arranged on the second receiving surface; the polluted sediment main layer group includes multiple polluted sediment layers and multiple waste biomass material layers, and the multiple polluted sediment layers are distributed on the bottom anti-seepage layer group at intervals along the vertical direction. A waste biomass material layer is provided between two adjacent polluted sediment layers, and the polluted sediment layer is prepared in situ by polluted sediment in the river; the ecological planting layer group includes ecological concrete, planting soil and herbaceous plants, the ecological concrete is laid on top of the polluted sediment main layer group, the planting soil is laid on top of the ecological concrete, and the herbaceous plants are planted on the planting soil.

[0008] In some embodiments, the seepage purification layer group also includes permeable concrete and permeable reinforced concrete. The permeable concrete is arranged on the gravity retaining wall, and the permeable concrete is arranged on the side away from the river channel; the permeable reinforced concrete is arranged on the gravity retaining wall, and the permeable reinforced concrete is arranged on the side close to the river channel, and the permeable reaction wall is arranged between the permeable concrete and the permeable reinforced concrete.

[0009] In some embodiments, the permeable reactive wall has a first permeability coefficient, the permeable concrete has a second permeability coefficient, and the permeable reinforced concrete has a third permeability coefficient; the permeability coefficient of the first permeability coefficient and / or the second permeability coefficient and / or the third permeability coefficient is selected in the range of 10 -3 -10 -4 m / s.

[0010] In some embodiments, the permeable reaction wall and the gravity retaining wall are detachably connected; the permeable reinforced concrete and the gravity retaining wall are connected by anchoring steel bars; a concrete support column group is also provided between the permeable reinforced concrete and the permeable concrete, and the concrete support column group includes multiple concrete support columns, and the multiple concrete support columns are arranged at intervals along the vertical direction.

[0011] In some embodiments, the bottom anti-seepage layer group includes a bedrock layer, a clay protective layer and a clay protective isolation membrane cloth. The bedrock layer is arranged on the second supporting surface; the clay protective layer is arranged above the bedrock layer; the clay protective isolation membrane cloth is arranged above the clay protective layer. The bedrock layer, the clay protective layer and the clay protective isolation membrane cloth are laid at a slope of 3-4%, and a contaminated bottom mud layer is provided above the clay protective isolation membrane cloth.

[0012] In some embodiments, the compaction degree of the bedrock layer is in the range of 0.93-0.96, the thickness of the clay protection layer is in the range of 500-1000 mm, and the clay protection isolation membrane is a polyester filament needle-punched non-woven geotextile with a thickness of 1.5-2 mm.

[0013] In some embodiments, the planting soil includes a sand and gravel layer, a plant compaction layer and a plant nutrient layer. The sand and gravel layer is arranged on the ecological concrete; the plant compaction layer is arranged on the sand and gravel layer; the plant nutrient layer is arranged on the plant compaction layer, and herbaceous plants are planted on the plant nutrient layer; the thickness of the plant compaction layer and / or the plant nutrient layer and / or the sand and gravel layer is 20-40 cm.

[0014] In some embodiments, the thickness of the contaminated sediment layer is 1-1.5 m, the thickness of the waste biomass material layer is 5-10 cm, and the biomass material in the waste biomass material layer is rice straw and / or stalks.

[0015] In some embodiments, the first bank protection foundation is obtained by stacking mortar-laid stone slabs, and the riverbed slope protection is obtained by filling with stone masonry, and the angle range of the riverbed slope protection is 45-60°; the base layer group also includes a gravel layer, a sand layer and aquatic plants. The gravel layer is arranged on the outer surface of the riverbed slope protection, mainly sand-free gravel with a particle size of more than 30 mm, and the thickness of the gravel layer ranges from 0.2 to 1 m; the sand layer is arranged on the outer surface of the gravel layer, and the thickness of the sand layer ranges from 10 to 50 cm; aquatic plants are planted on the sand layer.

[0016] In some embodiments, the gravity retaining wall is a vertical trapezoidal structure cast from C40 concrete, and the angle of the trapezoidal side is in a 1:1 ratio to the angle of the riverbed slope protection.

[0017] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0018] 1. In-situ resource utilization of contaminated sediments can not only solve the high transportation costs of long-distance transportation, but also solve the potential pollution risks caused by sediment landfill.

[0019] 2. Using waste biomass to create the waste biomass layer not only reduces the cost of the raw materials, but also, after decaying and decomposing, it increases the content of organic matter and humus in the contaminated sediment. Contaminated sediment contains a large number of fine particles, which, when combined with humus, increase the particle size, significantly improving the structure of the contaminated sediment and increasing its porosity. Humus also has a strong adsorption capacity for heavy metals, and organic matter can fix heavy metals through adsorption and chelation, reducing their migration capacity. Furthermore, placing the waste biomass at a 3-4% slope facilitates the drainage of water from the sediment.

[0020] 3. A seepage purification layer group with a permeable reaction wall is used. Rainwater or water contained in polluted sediment can enter the river channel through the seepage purification layer group, while pollutants such as heavy metals contained in the polluted sediment will be intercepted by the permeable reaction wall and will not enter the river channel again, causing repeated pollution.

[0021] 4. The construction of ecological planting layers can not only fix and absorb pollutants in the polluted sediment to a certain extent, but also improve the ecosystem near the river bank. The roots of plants can also play a certain role in fixing the entire ecological structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a cross-sectional view of the in-situ preparation of a permeable ecological bank protection structure from polluted river sediment;

[0024] Figure 2 It is a top view of the seepage purification layer group.

[0025] Reference numerals:

[0026] 1. The first revetment foundation;

[0027] 2. River bottom slope protection;

[0028] 3. Second revetment foundation;

[0029] 4. Clay layer;

[0030] 5. Polluted sediment;

[0031] 6. Clay protection isolation film cloth;

[0032] 7. Clay protective layer;

[0033] 8. Foundation stone layer;

[0034] 9. Waste biomass material layer;

[0035] 10. Ecological concrete;

[0036] 11. Sand and gravel layer;

[0037] 12. Plant nutrition layer;

[0038] 13. Plant compaction layer;

[0039] 14. Herbs;

[0040] 15. Permeable concrete;

[0041] 16. Permeable reactive wall;

[0042] 17. Permeable reinforced concrete;

[0043] 18. Gravity retaining wall;

[0044] 19. Gravel layer;

[0045] 20. Aquatic plants;

[0046] 21. Anchoring steel bars;

[0047] 22. Hole in the wall;

[0048] 23. Concrete support columns. DETAILED DESCRIPTION

[0049] The present invention will be described in further detail below with reference to the accompanying drawings and examples. It is particularly noted that the following examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Similarly, the following examples are only some embodiments of the present invention and are not intended to be exhaustive. All other embodiments obtained by those of ordinary skill in the art without creative effort are intended to fall within the scope of protection of the present invention.

[0050] See also Figure 1 and Figure 2 The present embodiment provides a permeable ecological revetment structure for in-situ preparation of polluted riverbed sludge 5, including a foundation layer group, a seepage purification layer group, a bottom anti-seepage layer group, a polluted sediment 5 main layer group and an ecological planting layer group. The foundation layer group includes a first revetment foundation 1, a second revetment foundation 3, a gravity retaining wall 18 and a riverbed slope protection 2. The first revetment foundation 1 is arranged at the bottom of the river and close to the edge of the river. The first revetment foundation 1 has a first receiving surface, which is arranged in a horizontal direction. The second revetment foundation 3 is connected to the second revetment foundation 3. A revetment foundation 1 is adjacently disposed and disposed on a side away from the river channel. A second revetment foundation 3 has a second receiving surface and a third receiving surface. The third receiving surface is disposed in a vertical direction. The height of the second receiving surface from the riverbed gradually decreases from the edge of the river channel to the river channel according to a preset gradient. A gravity retaining wall 18 is disposed on the first receiving surface and is also connected to the third receiving surface. A riverbed slope protection 2 is disposed on the first receiving surface and adjacent to the gravity retaining wall 18. The riverbed slope protection 2 is inclined at 45-60 degrees toward the river channel.

[0051] The seepage purification layer group is arranged on the gravity retaining wall 18, and the seepage purification layer group includes a permeable reaction wall 16, which is used to filter harmful substances in the accumulated water; the bottom anti-seepage layer group is arranged on the second receiving surface; the polluted sediment 5 main layer group includes multiple polluted sediment 5 layers and multiple waste biomass material layers 9, and the multiple polluted sediment 5 layers are distributed on the bottom anti-seepage layer group at intervals along the vertical direction. A waste biomass material layer 9 is provided between two adjacent polluted sediment 5 layers, and the polluted sediment 5 layers are prepared in situ by the river channel polluted sediment 5; the ecological planting layer group includes ecological concrete 10, planting soil and herbaceous plants 14, the ecological concrete 10 is laid on top of the polluted sediment 5 main layer group, the planting soil is laid on top of the ecological concrete 10, and the herbaceous plants 14 are planted on the planting soil.

[0052] In this embodiment, the subgrade group is a foundation structure for an ecological revetment. Specifically, the subgrade group includes a first revetment foundation 1, a second revetment foundation 3, a gravity retaining wall 18, and a riverbed slope protection 2. The first revetment foundation 1 is a foundation structure located near the riverbed and located at the riverbed. In some embodiments, the first revetment foundation 1 is formed by stacking mortared stone slabs. This structure is stable and has sufficient strength and rigidity to withstand horizontal earth pressure. The second revetment foundation 3 is located near the bank and can be made of natural foundation soil or existing soil from both sides of the riverbed. For the convenience of expression, the upper surface of the first revetment foundation 1 is recorded as the first receiving surface, the upper surface of the second revetment foundation 3 is recorded as the second receiving surface, and the side of the second revetment foundation 3 facing the first revetment foundation 1 is recorded as the third receiving surface. The third receiving surface is a vertical plane, the first receiving surface is a horizontal plane, and the height of the second receiving surface from the riverbed gradually decreases from the edge of the river channel to the river channel according to a preset gradient, presenting a certain slope. This setting can facilitate the guidance of rainwater and water flow on the shore, so that it can flow into the river channel under the action of gravity.

[0053] Specifically, the gravity retaining wall 18 is a vertical trapezoidal structure, and the two right-angled surfaces of the gravity retaining wall 18 correspond to the first receiving surface and the third receiving surface respectively. In some embodiments, the gravity retaining wall 18 is a vertical trapezoidal structure cast from C40 concrete. The specific size of the gravity retaining wall 18 can be selected according to the specific value of the soil pressure. The angle of the trapezoidal side is in a ratio of 1:1 to the angle of the riverbed slope protection 2. A riverbed slope protection 2 is provided on the side of the gravity retaining wall 18 facing the river channel. The height of the riverbed slope protection 2 is below the normal water level of the river channel. The riverbed slope protection 2 can use masonry stacking to form the main slope structure. The angle of the slope structure ranges from 45° to 60°. Gravel or sand is then laid on the outer surface of the riverbed slope protection 2. In some optional embodiments, the soil consolidation effect of the riverbed slope protection 2 can also be achieved by planting aquatic plants 20, thereby improving the structural stability of the riverbed slope protection 2.

[0054] This embodiment also includes a seepage purification layer group, which is arranged on the gravity retaining wall 18 and is used to filter the water flowing on the river bank. Specifically, the seepage purification layer group includes a permeable reaction wall 16, which can be constructed using a series of filler materials, such as activated carbon, iron powder, magnesium oxide, iron oxide, etc. These filler materials have adsorption, reduction, oxidation, and precipitation functions, and can chemically react with pollutants such as organic matter, heavy metals, and chlorides. When groundwater flows through the permeable reaction wall 16, the pollutants react with the filler materials, thereby reducing their concentration and converting them into harmless substances, reducing the impact on the surrounding environment. This has the advantages of flexible operation, relatively low cost, and low environmental impact. In some embodiments, the types of pollutants in the riverbed sediment are mostly cadmium-containing pollutants, and the filling material in the permeable reaction wall 16 is zero-valent iron. After the heavy metal ions in the contaminated sediment 5 come into contact with the permeable reaction wall 16 as the porous fluid, adsorption, oxidation, reduction, precipitation, degradation and other reactions occur, which intercept the pollutants in the wall, thereby allowing clean water to flow into the river, which has a good effect on improving the water quality of the river.

[0055] The bottom anti-seepage layer group is set on the second receiving surface to isolate the main layer group of the contaminated bottom mud 5 from the second revetment foundation 3 to reduce the impact of harmful substances in the contaminated bottom mud 5 on the soil quality of the second revetment foundation 3. It is laid at a slope of 3-4%.

[0056] The main contaminated sediment 5 layer group includes multiple contaminated sediment 5 layers and multiple waste biomass material layers 9. The contaminated sediment 5 used in the contaminated sediment 5 layers is the contaminated sediment 5 currently in the river channel. This allows for direct in-situ utilization of the river channel sediment, reducing transportation costs and the cost of handling the contaminated sediment 5. Furthermore, the contaminated sediment 5 layers are vertically spaced apart on the bottom impermeable layer group, with a waste biomass material layer 9 laid between two adjacent contaminated sediment 5 layers.

[0057] In some embodiments, the thickness of the contaminated sediment layer 5 is 1-1.5m, the thickness of the waste biomass material layer 9 is 5-10cm, and the biomass material of the waste biomass material layer 9 is rice straw and / or straw. Using cheap materials such as rice straw and straw, and laying them alternately with riverbed sediment, can guide the flow of water, thereby increasing the flow of the permeable structure and enhancing the seepage effect. After the waste biomass material rots, it can increase the content of organic matter and humus in the sediment. The sediment contains a large amount of fine particles, which increase the particle size after combining with humus, which can well improve the structure of the sediment and increase the porosity. At the same time, humus has a strong adsorption capacity for heavy metals, and organic matter can fix heavy metals through adsorption and chelation.

[0058] The ecological planting layer includes ecological concrete 10, planting soil, and herbaceous plants 14. The ecological concrete 10 is laid above the main layer of the contaminated sediment 5, the planting soil is laid above the ecological concrete 10, and the herbaceous plants 14 are planted on the planting soil. Cement is the main component of concrete, but its production process consumes a lot of energy and produces a large amount of carbon dioxide. Ecological concrete 10 reduces carbon emissions and cement consumption by reducing cement usage, for example, by using alternative materials, additives, and mixtures. Alternative materials such as fly ash, silica fume, and slag can reduce dependence on natural resources and reduce waste generation. Recycled concrete aggregates can also be used in ecological concrete 10, that is, waste concrete is recycled to reduce the demand for natural aggregates and reduce waste generation. By adding preservatives and reducing chloride ion penetration, the durability of the concrete structure is improved and its service life is extended. The herbaceous plants 14 can both play a reinforcing role and reduce the loss of planting soil. Moreover, the roots of the herbaceous plants 14 can also absorb heavy metal pollutants in the contaminated sediment 5 to a certain extent, thereby playing a role in fixing heavy metal pollutants.

[0059] This embodiment adopts an in-situ treatment method to dispose of the river polluted sediment 5. By utilizing the interception effect of the permeable reaction wall 16 on pollutants, the fixed chelation effect of straw and the purification effect of plants, the concentration of pollutants seeping into the river from the polluted sediment 5 can be effectively reduced, and the in-situ resource utilization of the river polluted sediment 5 can be achieved. It has the advantages of convenient construction, low construction cost and ecological protection.

[0060] See also Figure 1 and Figure 2 In some embodiments, the seepage purification layer group also includes permeable concrete 15 and permeable reinforced concrete 17. The permeable concrete 15 is arranged on the gravity retaining wall 18, and the permeable concrete 15 is arranged on the side away from the river channel; the permeable reinforced concrete 17 is arranged on the gravity retaining wall 18, and the permeable reinforced concrete 17 is arranged on the side close to the river channel, and the permeable reaction wall 16 is arranged between the permeable concrete 15 and the permeable reinforced concrete 17.

[0061] In this embodiment, permeable concrete 15, permeable reaction wall 16, and permeable reinforced concrete 17 form a sandwich structure. Permeable concrete 15 is a concrete material with excellent water permeability. By adding special aggregates to the concrete and controlling the concrete mix ratio, it allows water to pass through the concrete's pore structure, thereby achieving water infiltration and drainage. The main feature of permeable concrete 15 is that it can effectively reduce water accumulation and surface runoff, enhance groundwater replenishment and protect water resources. Permeable reinforced concrete 17 is a concrete material that is reinforced with steel bars on top of permeable concrete 15. Permeable reinforced concrete 17 has water permeability and a certain compressive strength, which can simultaneously meet drainage and load-bearing requirements.

[0062] In some embodiments, a plurality of wall holes 22 are provided at the bottom of the permeable reinforced concrete 17 . The wall holes 22 penetrate the permeable reinforced concrete 17 to enable replacement of the filling material of the permeable reaction wall 16 , facilitating maintenance.

[0063] In some embodiments, the permeable reaction wall 16 has a first permeability coefficient, the permeable concrete 15 has a second permeability coefficient, and the permeable reinforced concrete 17 has a third permeability coefficient; the permeability coefficient selection range of the first permeability coefficient and / or the second permeability coefficient and / or the third permeability coefficient is 10 -3 -10 -4 In this embodiment, the first permeability coefficient, the second permeability coefficient and the third permeability coefficient are consistent.

[0064] In some embodiments, the thickness of the permeable reaction wall 16 is determined based on the flow rate of water, the permeability coefficient and safety factor of the reaction medium, and the residence time of the pollutants. The thickness of the permeable reaction wall 16 can be determined according to formula (1), which is as follows:

[0065] B=SF·v·t

[0066] Where B is the minimum thickness of the permeable reactive wall 16 (m), SF is the safety factor, which is usually 1.5 to 2, v is the water velocity through the permeable reactive wall 16 (m / d), and t is the residence time (d). The residence time can be calculated according to formula (2), which is as follows:

[0067]

[0068] Among them, C T is the design concentration of downstream pollutants (mg / L), C0 is the pollutant concentration entering the PRB (mg / L), k is the reaction rate (1 / d), and according to the actual application conditions, the thickness of the permeable reaction wall 16 is at least 0.4m and at most 2m.

[0069] See also Figure 2 In some embodiments, the permeable reaction wall 16 is detachably connected to the gravity retaining wall 18; the permeable reinforced concrete 17 is connected to the gravity retaining wall 18 by anchoring steel bars 21; a group of concrete support columns 23 is also provided between the permeable reinforced concrete 17 and the permeable concrete 15, and the group of concrete support columns 23 includes a plurality of concrete support columns 23, and the plurality of concrete support columns 23 are arranged at intervals along the vertical direction.

[0070] Specifically, the anchoring steel bar 21 is a ribbed steel bar, the diameter of the anchoring steel bar 21 is not less than 14 mm, the spacing between the anchoring steel bars 21 is not greater than 200 mm, the anchoring length is not less than 600 mm, and the anchoring length is not less than 1 / 3 of the height of the seepage purification layer group. The surface of the anchoring steel bar 21 is coated with an anti-rust coating. The permeable concrete 15 and the permeable reinforced concrete 17 are connected every 2-3 m by concrete support columns 23. The concrete support columns 23 divide the space where the permeable reaction wall 16 is placed into several independent small cavities. The filling material required for the permeable reaction wall 16 is filled in the multiple small cavities to form the permeable reaction wall 16. Optionally, when a wall hole 22 is provided in the permeable reinforced concrete 17, the wall hole 22 is set in the centerline area of ​​each independent small cavity to facilitate the replacement of the filling material of the permeable reaction wall 16.

[0071] See also Figure 1 In some embodiments, the bottom anti-seepage layer assembly includes a bedrock layer 8, a clay protective layer 7, and a clay protective isolation membrane 6. The bedrock layer 8 is disposed on the second receiving surface; the clay protective layer 7 is disposed above the bedrock layer 8; and the clay protective isolation membrane 6 is disposed above the clay protective layer 7. A layer of contaminated bottom mud 5 is disposed above the clay protective isolation membrane 6. The bedrock layer 8, clay protective layer 7, and clay protective isolation membrane 6 are laid at a slope of 3-4%.

[0072] In some optional embodiments, a clay layer 4 is further included. The clay layer 4 and the permeable concrete 15 are arranged on both sides of the second bank protection foundation 3, and the middle area is used to place the main layer group of the contaminated bottom mud 5.

[0073] In some embodiments, the compaction degree of the bedrock layer 8 is in the range of 0.93-0.96, the thickness of the clay protection layer 7 is in the range of 500-1000 mm, and the clay protection isolation membrane cloth 6 is a polyester filament needle-punched non-woven geotextile with a thickness of 1.5-2 mm.

[0074] In some optional embodiments, the bottom anti-seepage layer group consists of a 600 mm thick foundation stone layer 8 with a compaction degree of 0.93, a 750 mm thick clay protection layer 7 and a 1.5 mm thick polyester filament needle-punched non-woven geotextile clay protection isolation membrane.

[0075] See also Figure 1 In some embodiments, the planting soil includes a sand and gravel layer 11, a plant compaction layer 13 and a plant nutrient layer 12. The sand and gravel layer 11 is arranged on the ecological concrete 10; the plant compaction layer 13 is arranged on the sand and gravel layer 11; the plant nutrient layer 12 is arranged on the plant compaction layer 13, and herbaceous plants 14 are planted on the plant nutrient layer 12; the thickness of the plant compaction layer 13 and / or the plant nutrient layer 12 and / or the sand and gravel layer 11 is 20-40 cm.

[0076] Specifically, the ecological planting layer consists of a 20cm-thick layer of ecological concrete 10, a 20cm-thick gravel layer 11, a 20cm-thick plant nutrient layer 12, and a 20cm-thick plant compaction layer 13. The herbaceous plants 14 planted on top of the layers not only reinforce the soil but also reduce soil erosion. Furthermore, the roots of the herbaceous plants 14 can, to a certain extent, absorb heavy metal pollutants from the bottom mud, thereby fixing these pollutants.

[0077] See also Figure 1 In some embodiments, the first bank protection foundation 1 is obtained by stacking mortar-laid stone slabs, and the riverbed slope protection 2 is obtained by filling with stone masonry. The angle of the riverbed slope protection 2 ranges from 45° to 60°. The foundation layer group also includes a gravel layer 19, a sand layer, and aquatic plants 20. The gravel layer 19 is arranged on the outer surface of the riverbed slope protection 2, mainly consisting of sand-free gravel with a particle size of more than 30 mm, and the thickness of the gravel layer 19 ranges from 0.2 to 1 m. The sand layer is arranged on the outer surface of the gravel layer 19, and the thickness of the sand layer ranges from 10 to 50 cm. The aquatic plants 20 are planted on the sand layer.

[0078] In this embodiment, the gravel layer 19 is located on the outer surface of the riverbed slope protection 2, which can play a role in resisting water scouring, protecting the stability of the river bank and preventing soil erosion. The sand layer is arranged on the outer surface of the gravel layer 19, which can provide finer pores and better drainage performance, allowing water to penetrate and drain faster. The aquatic plants 20 are planted on the sand layer, which can absorb nutrients in the water, filter water quality, provide a habitat, and contribute to the growth and reproduction of aquatic organisms. At the same time, the root system of the aquatic plants 20 can also increase the stability of the soil and prevent river bank erosion. By providing a gravel layer 19, a sand layer and aquatic plants 20, a suitable ecological environment can be created to promote plant growth, increase biodiversity, and repair damaged ecosystems.

[0079] In some optional embodiments, the thickness of the gravel layer 19 is 20 cm, and the height and width of the riverbed slope protection 2 are set according to hydrogeological conditions such as the normal water level of the river.

[0080] In some embodiments, the gravel layer 19 and the sand layer can be mixed and laid on the outer surface of the riverbed slope protection.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] 1. In-situ resource utilization of contaminated sediment 5 can not only solve the high transportation costs of long-distance transportation, but also solve the potential pollution risks caused by sediment landfill.

[0083] 2. Using waste biomass to form the waste biomass material layer 9 not only reduces the cost of the raw materials, but also, upon decay and decomposition, increases the organic matter and humus content in the contaminated sediment 5. The contaminated sediment 5 contains numerous fine particles, which, when combined with humus, increase their particle size, significantly improving the structure of the contaminated sediment 5 and increasing its porosity. Humus also has a strong adsorption capacity for heavy metals, while organic matter can immobilize heavy metals through adsorption and chelation, reducing their migration capacity. Furthermore, placing the waste biomass material at a certain slope facilitates the drainage of water from the sediment.

[0084] 3. A seepage purification layer group with a permeable reaction wall 16 is used. Rainwater or water contained in the polluted sludge 5 can enter the river channel through the seepage purification layer group, while pollutants such as heavy metals contained in the polluted sludge 5 will be intercepted by the permeable reaction wall 16 and will not enter the river channel again, causing repeated pollution.

[0085] 4. The construction of the ecological planting layer group can not only fix and absorb the pollutants in the polluted sediment 5 to a certain extent, but also improve the ecological system near the river bank. The root system of the plants can also play a certain role in fixing the entire ecological structure.

[0086] The above descriptions are only some embodiments of the present invention and do not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A permeable ecological bank protection structure prepared in situ from polluted river sediment, characterized in that: include: A foundation group includes a first bank protection foundation, a second bank protection foundation, a gravity retaining wall and a riverbed slope protection, wherein the first bank protection foundation is arranged at the bottom of the river channel and is arranged close to the edge of the river channel, the first bank protection foundation has a first receiving surface, and the first receiving surface is arranged in a horizontal direction, the second bank protection foundation is arranged adjacent to the first bank protection foundation and is arranged on a side away from the river channel, the second bank protection foundation has a second receiving surface and a third receiving surface, the third receiving surface is arranged in a vertical direction, and the height of the second receiving surface from the riverbed gradually decreases from the edge of the river channel to the river channel according to a preset gradient, the gravity retaining wall is arranged on the first receiving surface, and the gravity retaining wall is also connected to the third receiving surface, the riverbed slope protection is arranged on the first receiving surface and is adjacent to the gravity retaining wall, and the riverbed slope protection is inclined at 45-60 degrees toward the river channel; A seepage purification layer group is provided on the gravity retaining wall, wherein the seepage purification layer group includes a permeable reaction wall, and the permeable reaction wall is used to filter harmful substances in the accumulated water; A bottom anti-seepage layer group is arranged on the second receiving surface; The contaminated sediment main layer group includes multiple contaminated sediment layers and multiple waste biomass material layers, wherein the multiple contaminated sediment layers are vertically spaced apart on the bottom anti-seepage layer group, and a waste biomass material layer is provided between two adjacent contaminated sediment layers, and the contaminated sediment layers are prepared in situ from the contaminated sediment of the river; The ecological planting layer group includes ecological concrete, planting soil and herbaceous plants. The ecological concrete is laid above the contaminated sediment main layer group, the planting soil is laid above the ecological concrete, and the herbaceous plants are planted on the planting soil.

2. The in-situ permeable ecological bank protection structure prepared from river polluted sediment according to claim 1 is characterized in that: The seepage purification layer group also includes: Permeable concrete is arranged on the gravity retaining wall, and the permeable concrete is arranged on a side away from the river channel; The permeable reinforced concrete is arranged on the gravity retaining wall, the permeable reinforced concrete is arranged on the side close to the river channel, and the permeable reaction wall is arranged between the permeable concrete and the permeable reinforced concrete.

3. The in-situ permeable ecological bank protection structure prepared from polluted riverbed mud according to claim 2 is characterized in that: The permeable reactive wall has a first permeability coefficient, the permeable concrete has a second permeability coefficient, and the permeable reinforced concrete has a third permeability coefficient; The permeability coefficient of the first permeability coefficient and / or the second permeability coefficient and / or the third permeability coefficient is selected in the range of 10 -3 -10 -4 m / s.

4. The in-situ permeable ecological bank protection structure prepared from polluted riverbed mud according to claim 3 is characterized in that: The permeable reaction wall is detachably connected to the gravity retaining wall; The permeable reinforced concrete is connected to the gravity retaining wall via anchoring steel bars; A concrete support column group is further provided between the permeable reinforced concrete and the permeable concrete. The concrete support column group includes a plurality of concrete support columns, and the plurality of concrete support columns are arranged at intervals along the vertical direction.

5. The in-situ permeable ecological bank protection structure prepared from river polluted sediment according to claim 4 is characterized in that: The bottom anti-seepage layer group comprises: A foundation stone layer is provided on the second supporting surface; a clay protective layer disposed above the bedrock layer; The clay protection isolation membrane cloth is arranged above the clay protection layer, and the contaminated bottom mud layer is arranged above the clay protection isolation membrane cloth.

6. The in-situ permeable ecological bank protection structure prepared from river polluted sediment according to claim 5 is characterized in that: The compaction degree of the foundation stone layer is in the range of 0.93-0.96, the thickness of the clay protection layer is in the range of 500-1000 mm, and the clay protection isolation membrane cloth is a polyester filament needle-punched non-woven geotextile with a thickness of 1.5-2 mm.

7. The in-situ permeable ecological bank protection structure prepared from polluted riverbed mud according to claim 6 is characterized in that: The planting soil comprises: A sand and gravel layer is provided on the ecological concrete; a plant compaction layer, arranged on the sand and gravel layer; a plant nutrient layer, arranged on the plant compaction layer, on which the herbaceous plants are planted; The thickness of the plant compaction layer and / or the plant nutrition layer and / or the sand and gravel layer is 20-40 cm.

8. The in-situ permeable ecological bank protection structure prepared from polluted riverbed mud according to claim 7 is characterized in that: The thickness of the polluted bottom mud layer is 1-1.5 m, the thickness of the waste biomass material layer is 5-10 cm, and the biomass material in the waste biomass material layer is rice stalks and / or straw.

9. The in-situ permeable ecological bank protection structure prepared from polluted riverbed mud according to claim 8, characterized in that: The first bank protection foundation is obtained by stacking mortar-laid stone slabs, and the riverbed slope protection is obtained by filling with stone masonry; The base group also includes: A gravel layer is provided on the outer surface of the riverbed slope protection, and the thickness of the gravel layer ranges from 0.2 to 1 m; A sand layer is provided on the outer surface of the gravel layer, and the thickness of the sand layer ranges from 10 to 50 cm; Aquatic plants are planted on the sandy soil layer.

10. The in-situ permeable ecological bank protection structure prepared from polluted riverbed mud according to claim 9, characterized in that: The gravity retaining wall is a vertical trapezoidal structure cast with C40 concrete.

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