Ecological restoration system for debris flow gully bed
By adopting the Dingjian group structure and vegetation restoration method in the mudslide ditch bed, the problems of difficulty in vegetation growth of ditch beds and prone to failure of geotechnical engineering are solved, and the long-term stability and ecological restoration effect of ditch beds are achieved.
Patent Information
- Application Number
- CN202421332886.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-12
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-06-12
AI Technical Summary
Due to long-term water erosion, the vegetation growth environment is harsh, making it difficult to undergo ecological restoration. At the same time, geotechnical engineering measures are prone to failure and are difficult to manage in a stable manner for a long time.
The Dingba group structure is used as the basis to build cortex and tree forests, adjust the water flow direction through the Dingba group, protect the ditch bank and retaining walls, provide a stable growth environment, promote vegetation growth, and strengthen the stability of the ditch bed through the vegetation root system.
The problem of difficulty in growing vegetation in the channel is effectively solved. Through the reinforcement anchoring effect of the vegetation root system and the increase of soil cohesion, the stability of the ditch bed is improved, the problem of prone to failure of geotechnical engineering is avoided, and long-term ecological restoration and treatment effects are achieved.
Smart Images
Figure CN222935903U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of small watershed treatment of debris flow gullies, and particularly relates to a method for ecological restoration of the gully bed of a debris flow gully. Background Art
[0002] The strong scouring of debris flows causes drastic changes in the gully bed. The gully bed is cut down due to abrasion, and landslides and collapses occur at the foot of the gully bank due to undercutting, increasing the probability of debris flow occurrence and at the same time increasing the difficulty of ecological restoration within the watershed. Due to the long-term flow of water and mud flow through the gully bed of the debris flow gully, the water erosion is severe, the nutrient substances are scarce, the plant growth environment is harsh, and the ecological restoration is difficult. Therefore, developing an ecological restoration system for the gully bed of a debris flow gully has great social, economic and ecological environmental significance.
[0003] The measures for debris flow control mainly rely on geotechnical engineering measures, which have significant effects in the short term. However, large-scale engineering measures may damage the ecological integrity of the watershed, and geotechnical engineering has timeliness. Once it fails, it may amplify the disaster. Ecological engineering can stabilize the gully bed, protect the foot of the gully bank, and effectively inhibit the occurrence of debris flows. However, simple ecological engineering measures are slow to take effect and are difficult to implement. Therefore, the collaborative governance of geotechnical-ecological can inhibit the occurrence of debris flows in the short term and at the same time further repair the damaged ecological system of the watershed.
[0004] The utility model provides an ecological restoration system based on the structure of a groin group, and ecologically restores the gully bed of a debris flow gully through geotechnical-ecological measures. In river channel regulation, the groin, as an important measure of the dike project, is widely used. Its characteristics of adjusting water flow, reducing speed and dissipating energy, and protecting the river bank or gully bank can also play a role in the treatment of debris flow gullies. The groin group in the debris flow gully can adjust the drainage of the mud flow, protect the gully bank, and at the same time the gully bed between the groins is less eroded by the flowing water, providing a stable growth environment for vegetation. At the same time, the root systems of plants can effectively stabilize the soil structure of the gully bed, preventing erosion and downcutting of the gully bed. Summary of the Invention
[0005] The technical problem to be solved by the utility model is: to provide an ecological restoration system for the gully bed of a debris flow gully, that is, an ecological restoration method of constructing a crust layer and planting arbors in the gaps of a groin group based on the groin group structure, providing a stable growth environment for vegetation through the groin group, and solving the problem of difficult vegetation growth in the gully. After the vegetation matures, the reinforcement and anchoring effect of its root system on the gully bed and the increase in soil cohesion also further protect the groin group from being washed away by the water flow in the gully, solving the problem that geotechnical engineering is prone to failure.
[0006] To achieve the above technical features, the technical solution provided by the utility model is:
[0007] A debris flow gully bed ecological restoration system proposed by the present utility model includes retaining walls longitudinally arranged at the toe of slopes on both sides of the gully bed with a certain burial depth, a group of downstream-inclined spur dikes connected to the retaining walls, arbor forests between every two spur dikes longitudinally on the same side, and a reconstructed soil crust layer covering the gaps between the spur dikes.
[0008] The debris flow gully bed ecological restoration system of the present utility model. The retaining walls are arranged along both sides of the gully, and are designed in a continuous broken line form at the curved part of the gully. The inclination angle along the gully direction is the same as the gully bed line (designed as a continuous segmented broken line when the gully bed gradient changes greatly). The burial depth of the retaining wall is determined by calculating the bearing capacity of the debris flow gully bed and the earth pressure on both side slopes. The cross-section in the vertical direction along the gully is a trapezoid with a narrow top and a wide bottom, the top and the bottom are horizontal, the side in contact with the slope soil body is a vertical plane, and the side close to the gully is an inclined plane with an included angle of 85° with the horizontal plane. This structure with a narrow top and a wide bottom is beneficial to improving the anti-overturning ability of the retaining wall, while reducing the building materials used and the self-weight of the retaining wall, especially reducing problems such as the settlement of the retaining wall on the debris flow gully bed.
[0009] The debris flow gully bed ecological restoration system of the present utility model. The group of spur dikes is arranged symmetrically about the center line of the debris flow gully with the spur dikes on both banks. The same side of the group of spur dikes is arranged at a certain interval between every two spur dikes, and the interval L is 1-2 times the length B of the spur dike, following the arrangement rule that the greater the gully bed gradient, the smaller the spur dike interval. The height difference H 3 between two levels of the group of spur dikes is determined by the gully bed gradient of the debris flow gully. The sum of the lengths B of each level of spur dike in the direction perpendicular to the gully of the group of spur dikes should be less than the gully width D (i.e., the interval between the retaining walls on both sides), that is, the spur dike is only connected to one side of the retaining wall, and there is a water passage left between the symmetrically arranged group of spur dikes on both sides. The width of the water passage is 2-3 times the maximum particle size of the debris flow source material.
[0010] The spur dike is a downstream-inclined spur dike, and forms an inclination angle a with the retaining wall, and the value of the inclination angle a is 45°-75°; this inclination angle is beneficial to the flow concentration and drainage of the debris flow, reduces the scouring erosion of the gully bed between adjacent spur dikes on the same side, and at the same time the inclination angle is beneficial to the discharge of the debris flow entering the space between adjacent spur dikes on the same side and reduces the accumulation.
[0011] The spur dike is higher at the connection end with the retaining wall and lower at the end near the middle of the gully in the vertical direction along the retaining wall; the cross slope ratio 1:n of the height difference h to the length B of the spur dike in the vertical direction of the retaining wall is 1:4-1:20; this structure is beneficial to improving the stability of the overall structure. When a large debris flow occurs, the height near the middle flow passage is lower, and the debris flow can flow over the spur dike, reducing the impact force of the debris flow on the spur dike and being beneficial to the drainage of the debris flow.
[0012] In the longitudinal direction of the retaining wall, the top width of the spur dike is 1 <Bottom width b 2 , top width b 1 The width of the bottom is 0.6-1.2m, and the width of the bottom is 1.0-1.8m; the upstream side is vertical, and the downstream side is inclined; the height of the downstream inclined surface is H 1 With bottom width b 2 、Top width b 1 The downstream gradient of the difference ratio 1:m is 1:0.4-1:1, that is, 1:m=1:(b 2 -b 1 ). This proportion structure of narrow top and wide bottom is conducive to the stability of the spur dike under the impact of debris flow.
[0013] The utility model discloses a method for ecological restoration of debris flow gully beds. The species of the tree forest and crust layer herbs between each two-level spur dikes on the same side are selected as native species; the species selection method selects the ecological area where the watershed is located as the target, obtains the list of major native trees and herbs in the area through on-site investigation, literature research, etc., screens them according to their life history, growth characteristics, reproductive characteristics, etc., and establishes a native species library for watershed ecological restoration. At least one tree with a well-developed taproot system and one tree with a well-developed lateral root system are selected for matching planting, and seeds of herbs with well-developed root systems are selected as one of the raw materials for reconstructing the soil crust layer.
[0014] The arrangement form is staggered planting, and species with developed taproot systems and species with developed lateral root systems are planted alternately; the spacing between the species in the arrangement form is c, and the spacing c is the lateral extension length c of the root system of the plant with developed lateral root system at the mature stage. 1 OK, specifically 0.5c 1 <c<0.7c 1 ; Ensure that the plant roots can cover all the soil when mature, and at the same time ensure that the plants have sufficient growth space and nutrients; this arrangement is conducive to the coordination of species with well-developed taproot systems and lateral root systems, ensuring the stability of the overall plant community and soil and water conservation capabilities.
[0015] The arbor planting method is reconstituted soil planting, specifically as follows: Dig a planting pit, which is a cylinder with a diameter of 60 cm and a height of 100 cm; Place a vegetation basket, and fill it with the reconstituted soil made by fully mixing the in-situ soil dug out, loess suitable for plant growth in the watershed, degradable substances such as loofah sponges and straws, and fertilizers; The distance from the bottom of the tree roots to the bottom of the planting pit is 20 cm (ensuring that there is a reconstituted soil layer with a thickness of not less than 20 cm under the plant roots). The distribution of the arbor planting soil layer is the upper reconstituted soil layer and the lower capillary anti-seepage layer; Materials such as loofah sponges and straws in the reconstituted soil layer play a role in reinforcing the reconstituted soil, reducing the loss of the reconstituted soil, and their water absorption ability can also play a role in retaining water; The capillary anti-seepage layer is fine-grained soil or capillary material, which adjusts the water infiltration of the arbor vegetation reconstituted soil layer through the principle of capillary water migration, and solves the problem of excessive water infiltration caused by the large porosity of the gully bed deposits.
[0016] The vegetation basket is a woven basket made of degradable materials; The degradable materials can be selected from straw strips, crop straws, bamboo strips, etc.; The weaving method is the four-corner hole bottom weaving method, where the warp and weft strips pick one and press one, intersect and weave up and down, are arranged parallel at equal distances, leaving square holes, and the side length of the square holes is 2 cm - 5 cm.
[0017] The crust layer in the spur dike gap is the in-situ reconstituted soil layer; The reconstituted soil of the crust layer is made by fully mixing the deposits on the gully bed surface, loess suitable for plant growth in the watershed, herbaceous seeds with well-developed roots such as bermudagrass, degradable substances such as loofah sponges and straws, and fertilizers; The thickness of the reconstituted soil of the crust layer is 15 cm - 20 cm, and the coverage range is the entire range of the adjacent spur dike gaps on the same side. The herbs in the crust layer are part of the ecological restoration. Covering on the gully bed deposits can play a certain role in anti-seepage, and can also control water evaporation, solve the problem of fast evaporation rate of the loose deposits on the gully bed, and play a role in maintaining the stability of the gully bed soil state.
[0018] Compared with the prior art, the beneficial effects and advantages of the present utility model are as follows:
[0019] 1. The structure of the spur dike group inclined downstream is beneficial to the flow confinement and drainage of debris flows. By changing the flow direction of debris flows and when no debris flow occurs, it reduces the scouring of the gully bed, retaining wall and spur dikes between adjacent spur dikes on the same side, ensuring the environmental stability between adjacent spur dikes on the same side. At the same time, the inclination angle is beneficial to the discharge of debris flows between adjacent spur dikes on the same side, reducing their accumulation in the spur dike gaps on the same side.
[0020] 2. The T-shaped dike adjusts the flow direction of water and mud flow, protects the gully bank and retaining wall from being eroded by flowing water, and ensures the stability of the retaining wall foundation; At the same time, the support effect of the spur dike on the retaining wall effectively improves the anti-overturning ability of the retaining wall. Through the cooperation of the spur dike and the retaining wall, the stability of the gully bank is ensured, and the loose material sources on the slope are stabilized, thus being able to inhibit the occurrence of debris flows.
[0021] 3. The structure of the spur dike with a lower elevation near the center of the gully bed and a higher elevation at the connection with the retaining wall is conducive to the debris flow flowing over the spur dike during the occurrence of a large-scale debris flow, reducing the contact area of the debris flow with the overall engineering structure, thereby reducing its impact damage on the overall structure and ensuring the stability of the overall structure during the occurrence of a large-scale debris flow.
[0022] 4. Adding degradable materials such as loofah sponges and straw to the reconstructed soil can play a role in retaining moisture and at the same time increase the erosion resistance of the reconstructed soil; the vegetation basket is woven from degradable materials such as straw or stalks, which can reduce the erosion of the water flow in the soil layer in the loose accumulated materials in the gully bed during the initial growth stage of the arbor, and will not inhibit the growth of its roots during the growth process of the arbor.
[0023] 5. The distribution structure of the planting soil layer from top to bottom is the crust layer covering the entire range of the spur dike gap, the reconstructed soil layer in the arbor planting basket, and the fine-grained capillary water-blocking layer under the reconstructed soil layer. The advantages of such a soil layer combination are as follows: the crust layer can fix moisture and at the same time prevent the evaporation of the soil layer below it, solving the problem of easy evaporation of moisture in the loose accumulated materials in the debris flow gully bed; the fine-grained capillary water-blocking layer can effectively prevent the excessive infiltration of the moisture in the reconstructed soil layer in the vegetation basket through the principle of capillary water migration, solving the problem of serious infiltration in the loose accumulated materials in the debris flow gully bed.
[0024] 6. When the growth and development of the plants in the spur dike gap reach a certain degree, the reinforcement and anchoring effect of the plant roots on the gully bed materials and the improvement effect of their physical and chemical properties on the soil cohesion can reduce the erosion of the water flow and mud flow on the gully bed, which can in turn improve the stability of the spur dike and the retaining wall foundation, and can solve the problem of easy failure of geotechnical engineering. Description of the Drawings
[0025] Figure 1 It is the layout diagram of the ecological restoration system for the debris flow gully bed
[0026] Figure 2 It is the structure diagram of the retaining wall and the spur dike
[0027] Figure 3 It is the longitudinal layout diagram of the spur dike group
[0028] Figure 4 It is the schematic diagram of the arrangement method of arbor planting
[0029] Figure 5 It is the schematic diagram of the arbor planting basket and the soil layer design therein
[0030] Figure 6 It is the cross-sectional diagram of the ecological restoration system for the debris flow gully bed
[0031] The labels in the figures are as follows:
[0032] 1 Retaining wall 2 Spur dike
[0033] Plant community in the gap between three spur dikes
[0034] Lateral length of spur dike B in the vertical direction of the retaining wall
[0035] a Inclination angle D Width of debris flow drainage channel
[0036] b 1 Bottom width b of the spur dike 2 Top width of the spur dike
[0037] H Burial depth of the spur dike L Spacing between every two levels of the spur dike
[0038] Height difference h between the head and root of the spur dike H 1 Height of the upstream inclined plane of the spur dike
[0039] H 3 Height difference between adjacent two levels of the spur dike
[0040] 1:n Cross slope gradient 1:m Upstream side gradient
[0041] c Spacing between tree rows 4 Vegetation basket
[0042] 5 Reconstructed soil layer for tree planting on the spur dike 6 Capillary water-blocking layer
[0043] 7 Crust layer Specific implementation manner
[0044] The structure of an ecological restoration method for the debris flow gully bed provided by the present utility model is as Figure 1 shown, and it includes retaining walls 1 on both sides, a stepped spur dike group 2 disposed therebetween, connected thereto and used in cooperation, and a tree forest 3 planted among the spur dike group.
[0045] As Figure 1 shown, every two spur dikes on the same side of the stepped spur dike group are arranged at a certain spacing. The spacing L is 1 - 2 times the length B in the direction perpendicular to the gully channel. The greater the gully bed gradient, the smaller the spur dike spacing. The spur dike group 1 is symmetrically arranged on the left and right with respect to the center line of the debris flow gully by the spur dikes on both banks. A group of spur dikes that are symmetrically arranged on the left and right together constitute one level of the spur dike group. The sum of the lengths B in the direction perpendicular to the gully channel of each level of the spur dike in the stepped spur dike group should be less than the gully channel width D (i.e., the spacing between the retaining walls on both sides), that is, the spur dikes on both sides of each level are not connected to each other, and each spur dike is only connected to one side of the retaining wall. A water passage is left between the spur dike groups that are symmetrically arranged on both sides, and the width of the water passage is 2 - 3 times the maximum particle size of the debris flow source in the basin.
[0046] As Figure 1As shown in the figure, the spur dike and the retaining wall form an inclined angle a and slope downstream, that is, the section of the spur dike connected to the retaining wall is higher than the other end located upstream of the channel; this design of the inclined angle is beneficial to the flow concentration of debris flow, ensuring the environmental stability between adjacent spur dikes on the same side, and at the same time reducing the accumulation between the gaps of spur dikes on the same side.
[0047] As Figure 2 shown in the figure, the cross-section of the retaining wall along the vertical direction of the channel is a trapezoid with a narrow top and a wide bottom, and the top and bottom are kept horizontal; the side in contact with the slope soil is a plane perpendicular to the horizontal plane, and the side close to the channel is an inclined plane with an included angle of 85° with the horizontal plane.
[0048] As Figure 2 shown in the figure, along the vertical direction of the retaining wall, the end of the spur dike close to the retaining wall is high, and the end close to the middle of the channel is low; the cross-slope ratio of the height difference h to the length B of the spur dike in the vertical direction of the retaining wall is 1:n, which is 1:4 - 1:20.
[0049] As Figure 2 shown in the figure, the materials of the overall structure of the retaining wall and the spur dike are reinforced concrete. The distance between every two steps of the spur dike is 5 - 15m, the height of the retaining wall is 3m, the buried depth is 1.8m, and the buried depth of the spur dike is 0.5 - 1m.
[0050] As Figure 3 shown in the figure, along the longitudinal direction of the retaining wall, the top width b of the spur dike 1 < the bottom width b 2 , the upstream side is vertical, and the downstream side is inclined; the top width b 1 is 0.6 - 1.2m, and the bottom width is 1.0 - 1.8m; the height H of the inclined surface on the downstream side 1 and the difference between the bottom width b 2 and the top width b 1 The downstream side slope ratio 1:m is 1:0.4 - 1:1, that is, 1:m = 1:(b 2 -b 1 ). This structure with a narrow top and a wide bottom is beneficial to the stability of the spur dike under the impact of debris flow.
[0051] As Figure 4 shown in the figure, the planting form is staggered row planting, with straight root - developed species and lateral root - developed species planted at intervals, and the row - column spacing of the arrangement form is c.
[0052] As Figure 5As shown in the figure, the vegetation basket 4 is a woven basket made of degradable materials; the degradable materials can be selected from rice straw strips, crop straws, bamboo strips, etc.; the weaving method is the four-corner hole bottom weaving method, where the warp and weft strips are picked one and pressed one, woven up and down alternately, arranged parallel at equal distances, leaving square holes, and the side length of the square holes is 2 cm - 5 cm. The tree planting and reconstructing soil layer 5 is a mixture of in-situ soil, loess suitable for plant growth in the basin, degradable substances such as loofah sponges and straws, and fertilizers; the capillary barrier layer 6 is a fine-grained soil layer or capillary material.
[0053] As Figure 6 shown, the dike gap crust layer 7 is a reconstructed in-situ soil layer; the reconstructed soil of the crust layer is a mixture of sediment on the gully bed surface, loess suitable for plant growth in the basin, well-developed root herb seeds such as bermudagrass, degradable substances such as loofah sponges and straws, and fertilizers; the thickness of the reconstructed soil of the crust layer 7 is 15 cm - 20 cm, and the coverage range is the entire range of the adjacent dike gaps on the same side.
[0054] Example 1: Ecological restoration of Goulinping debris flow gully
[0055] As Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 shown, for a debris flow gully with a channel bed slope of 5% and a channel width D of 25 m. The locally dominant species with well-developed taproots is Melia azedarach, and the species with well-developed lateral roots is Robinia pseudoacacia.
[0056] The length B of the stepped dike group in the direction perpendicular to the channel is 8 m, and the spacing L between every two dikes on the same side is 15 m. The dike group 1 is arranged symmetrically about the center line of the debris flow gully by the dikes on both banks, and a group of symmetric dikes on the left and right together form one level of the dike group. The dikes on both sides of each level are not connected to each other, and each dike is only connected to one side of the retaining wall. There is a water passage with a width of 3 m left between the symmetric dike groups on both sides.
[0057] As Figure 1 shown, the inclination angle a between the dike and the retaining wall is 60°, and it slopes downstream, that is, the section of the dike connected to the retaining wall is located upstream of the other end in the channel; this design of the inclination angle is beneficial to the flow constriction of the debris flow, ensuring the environmental stability between adjacent dikes on the same side, and at the same time reducing the accumulation in the dike gaps on the same side.
[0058] As Figure 2 shown, the cross-section of the retaining wall along the vertical direction of the channel is a trapezoid with a narrow top and a wide bottom, and the top and bottom are horizontal; the side in contact with the slope soil is a plane perpendicular to the horizontal plane, and the side close to the channel is an inclined plane, with an included angle of 85° with the horizontal plane.
[0059] As Figure 2As shown, the spur dike is higher at the end adjacent to the retaining wall and lower at the end adjacent to the middle of the channel in the direction perpendicular to the retaining wall; the cross slope ratio 1:n of the height difference h to the length B of the spur dike in the direction perpendicular to the retaining wall is 1:12.
[0060] As Figure 2 shown, the materials of the overall structure of the retaining wall and the spur dike are reinforced concrete. The distance between every two steps of the stepped spur dike is 10m, the height of the retaining wall is 3m, the embedment depth is 1.8m, and the embedment depth of the spur dike is 0.8m.
[0061] As Figure 3 shown, in the longitudinal direction of the retaining wall, the top width b of the spur dike 1 < bottom width b 2 , the upstream side is vertical, and the downstream side is inclined; the top width b 1 is 0.8m, and the bottom width is 1.4m; the height H of the inclined surface on the downstream side 1 and the difference between the bottom width b 2 , top width b 1 ratio of the downstream side slope 1:m is 1:0.58, that is, 1:m = 1:(b 2 -b 1 ) = 1:0.58. This structure with a narrower top and wider bottom is beneficial for the spur dike to maintain stability under the impact of debris flow.
[0062] As Figure 4 shown, the planting form is staggered row planting, with species with well-developed taproots and species with well-developed lateral roots planted at intervals, and the row spacing of the arrangement form is 1m.
[0063] As Figure 5 shown, the vegetation basket 4 is a woven basket made of degradable materials; the degradable materials are selected as crop straws; the weaving method is the four-corner hole bottom weaving method, with the warp and weft strips picking one and pressing one, crossing and weaving up and down, arranged in parallel at equal distances, leaving square holes, and the side length of the square holes is 2cm - 5cm. The tree vegetation reconstruction soil layer 5 is a fully mixed layer of in-situ soil, loess suitable for plant growth in the basin, degradable substances such as loofah sponges and straws, and fertilizers; the capillary barrier layer 6 is a fine-grained soil layer.
[0064] As Figure 6 shown, the spur dike gap crust layer 7 is an in-situ reconstructed soil layer; the reconstructed soil of the crust layer is a fully mixed layer of sediment on the surface of the gully bed, loess suitable for plant growth in the basin, well-developed herb seeds with roots such as bermudagrass, degradable substances such as loofah sponges and straws, and fertilizers; the thickness of the reconstructed soil of the crust layer 7 is 15cm, and the coverage range is the entire range of the gap between adjacent spur dikes on the same side.
[0065] Example 2:
[0066] As Figure 1 、 Figure 2 、 Figure 3 、Figure 4 , Figure 5 As shown in Figure 5 , for the debris flow gully with a channel bed slope of 30% and a channel width D of 20 m. The dominant local species with well-developed taproots is Melia azedarach, and the species with well-developed lateral roots is Robinia pseudoacacia.
[0067] The length B of the stepped groyne group in the direction perpendicular to the channel is 7 m, and the spacing L between every two groynes on the same side is 9 m. The groyne group 1 is arranged symmetrically about the center line of the debris flow gully on both sides of the bank. A set of symmetric groynes on the left and right together form one level of the groyne group. The groynes on both sides of each level are not connected to each other. Each groyne is only connected to one side of the retaining wall. There is a water passage with a width of 3 m left between the symmetric groyne groups on both sides.
[0068] As Figure 1 shown, the groyne makes an inclined angle a of 60° with the retaining wall and slopes downstream, that is, the section of the groyne connected to the retaining wall is higher than the other end located upstream of the channel; this design of the inclined angle is beneficial to the flow constriction of the debris flow, ensuring the environmental stability between adjacent groynes on the same side and reducing the accumulation in the gaps between the groynes on the same side.
[0069] As Figure 2 shown, the cross-section of the retaining wall along the vertical direction of the channel is a trapezoid with a narrow top and a wide bottom, and the top and bottom are horizontal; the side in contact with the slope soil is a plane perpendicular to the horizontal plane, and the side close to the channel is an inclined plane with an included angle of 85° with the horizontal plane.
[0070] As Figure 2 shown, the groyne is higher at the end close to the retaining wall and lower at the end close to the middle of the channel in the direction perpendicular to the retaining wall; the cross-slope ratio 1:n of the height difference h to the length B of the groyne in the direction perpendicular to the retaining wall is 1:8 (in this embodiment, the channel bed slope is relatively large, and the flow velocity of the debris flow may be relatively fast during the occurrence of the debris flow. Setting a larger cross-slope ratio at the top of the groyne can enable the debris flow to flow over the groyne during the occurrence of a large debris flow).
[0071] As Figure 2 shown, the materials of the overall structure of the retaining wall and the groyne are reinforced concrete. The distance between every two steps of the stepped groyne is 10 m, the height of the retaining wall is 3 m, the embedment depth is 1.8 m, and the embedment depth of the groyne is 0.8 m.
[0072] As Figure 3 shown, in the longitudinal direction of the retaining wall, the top width b of the groyne 1 < the bottom width b 2 , the upstream side is vertical, and the downstream side is inclined; the top width b 1 is 0.8 m, and the bottom width is 1.4 m; the height H of the inclined surface on the downstream side 1 and the bottom width b 2 , the top width b 1The downstream slope ratio 1:m of the difference ratio is 1:0.58, i.e., 1:m = 1:(b 2 -b 1 ) = 1:0.58. This structure that is narrow at the top and wide at the bottom is conducive to the stability of the spur dike under the impact of debris flow.
[0073] As Figure 4 shown, the planting form is staggered row planting, with straight root system developed species and lateral root system developed species planted at intervals, and the row spacing of the arrangement form is 1m.
[0074] As Figure 5 shown, the vegetation basket 4 is a woven basket made of degradable materials; the degradable materials are selected as crop straws; the weaving method is the four-corner hole bottom weaving method, with the warp and weft strips picking one and pressing one, weaving up and down alternately, arranged in parallel at equal distances, leaving square holes, and the side length of the square holes is 3cm. The tree vegetation reconstruction soil layer 5 is a fully mixed soil of in-situ soil, loess suitable for plant growth in the basin, degradable substances such as loofah sponges and straws, and fertilizers; the capillary barrier layer 6 is a fine-grained soil layer.
[0075] As Figure 6 shown, the spur dike gap crust layer 7 is an in-situ reconstructed soil layer; the reconstructed soil of the crust layer is a fully mixed soil of the accumulated materials on the gully bed surface, loess suitable for plant growth in the basin, herbaceous seeds with developed root systems such as bermudagrass, degradable substances such as loofah sponges and straws, and fertilizers; the thickness of the reconstructed soil of the crust layer 7 is 20cm, and the coverage range is the entire range of the adjacent spur dike gaps on the same side.
Claims
1. A debris flow gully bed ecological restoration system, characterized in that: It includes retaining walls (1) on both sides, a group of groins (2) between, connected to and used in conjunction with the groins, a tree forest (3) planted between the groins, and a crust layer (7) covering the entire range of the groin gap on the same side.
2. The debris flow ditch bed ecological restoration system according to claim 1 is characterized in that: The material of the overall structure of the retaining wall and the spur dike is reinforced concrete. The spur dike group (2) is composed of spur dikes on both sides arranged symmetrically with respect to the center line of the debris flow ditch. The sum of the lengths B of the spur dikes on both sides of each level in the direction perpendicular to the ditch should be less than the ditch width D, that is, the spur dikes on both sides are not connected to each other, and each spur dike is only connected to one side of the retaining wall. A water passage is left between the symmetrical spur dike groups on both sides. The width of the water passage is selected to be 2-3 times the maximum particle size of the debris flow source.
3. The debris flow ditch bed ecological restoration system according to claim 1 is characterized in that: The distance between every two levels on the same side of the spur dike group is 5-15m, the height of the retaining wall is 3m, the buried depth of the spur dike is 1.8m, and the buried depth of the spur dike is 0.5-1m; the distance L between every two spur dikes on the same side of the spur dike group is 1-2 times the length B in the vertical channel direction. The greater the gradient of the ditch bed, the smaller the distance between the spur dikes; the spur dikes of the spur dike group are downward-projecting spur dikes, and the spur dikes and the retaining wall are inclined at an angle a.
4. The debris flow ditch bed ecological restoration system according to claim 1 is characterized in that: The cross-section of the retaining wall along the vertical direction of the channel is a trapezoid with a narrow top and a wide bottom, and the top and bottom are horizontal; the side in contact with the slope soil is a plane perpendicular to the horizontal plane, and the side close to the channel is an inclined surface with an angle of 85° to the horizontal plane.
5. The debris flow ditch bed ecological restoration system according to claim 1 is characterized in that: The spur dike is higher at one end close to the retaining wall and lower at the middle of the channel in the vertical direction of the retaining wall; the transverse slope ratio 1:n of the ratio of the height difference h to the length B of the spur dike in the vertical direction of the retaining wall is 1:4-1:
20.
6. The debris flow ditch bed ecological restoration system according to claim 1 is characterized in that: In the longitudinal direction of the retaining wall, the top width b1 of the spur dike is less than the bottom width b2, the upstream side is vertical, and the downstream side is inclined; the top width b1 is 0.6-1.2m, and the bottom width is 1.0-1.8m; the downstream side gradient 1:m of the ratio of the downstream side inclined surface height H1 to the difference between the bottom width b2 and the top width b1 is 1:0.4-1:
1.
7. The debris flow ditch bed ecological restoration system according to claim 1 is characterized in that: The planting form of the tree forest established between the groins is staggered planting, and species with well-developed taproot systems and well-developed lateral root systems are planted alternately; the spacing between species in the row arrangement is c, which is determined by the lateral extension length c1 of the root system of plants with well-developed lateral root systems at the mature stage, specifically 0.5c1 <c<0.7c1。 8. The debris flow ditch bed ecological restoration system according to claim 1 is characterized in that: The crust layer in the gap between groins is an in-situ reconstructed soil layer; the reconstructed soil of the crust layer is a thorough mixture of the ditch bed surface deposits with loess, dogtooth grass seeds, loofah sacs, straw and fertilizers suitable for plant growth in the basin; the thickness of the reconstructed soil of the crust layer is 15cm-20cm, and the coverage range is the entire range of the gap between adjacent groins on the same side; the herbs in the crust layer are part of the ecological restoration, and their covering on the ditch bed deposits can play a role in seepage prevention and control water evaporation.