Sludge solidification silt dam structure based on composite reinforcement and damming method

Abstract

The invention relates to the technical field of water conservancy and hydropower and geotechnical engineering, and particularly discloses a silt solidification silt dam structure based on composite reinforcement and a damming method.The silt dam structure comprises a silt dam body formed by artificial aggregate layered filling formed by solidified silt crushing and screening; the geomembrane, the geogrid, the geobag, the ecological bag and the inverted filter drainage layer are arranged in a composite mode. The damming method comprises the steps that reservoir dredged sludge and an industrial solid waste curing agent are mixed, cured, crushed and screened into artificial aggregate; artificial aggregates are filled in a layered mode, geogrids are laid synchronously, the geogrids are used for reversely wrapping and fixing the soil bags of the downstream slope, and meanwhile ecological bags are laid; and finally, geomembranes are laid to complete seepage prevention and slope protection. According to the dam body, efficient resource utilization of desilting silt is achieved, the stability, seepage-proofing performance and ecological adaptability of the dam body are remarkably improved through the composite reinforcement and ecological protection technology, and the dam body is particularly suitable for loess plateau areas.

Description

Technical Field

[0001] This invention relates to the fields of water conservancy, hydropower and geotechnical engineering, and in particular to a silt-stabilizing dam structure and construction method based on composite reinforcement. Background Technology

[0002] The Loess Plateau region of the Yellow River Basin is dotted with numerous small and medium-sized reservoirs, mostly located in rural areas. These reservoirs not only serve vital functions such as irrigation, water supply, and flood control, but are also closely related to the sustainable economic and social development and the stability of the ecosystem in the region. However, due to the extremely high sediment yield modulus in the Loess Plateau region, these reservoirs generally face severe siltation problems during long-term operation, seriously affecting their beneficial functions and flood control capabilities.

[0003] The silt deposited in the Loess Plateau region is characterized by fine particles, high water content, and strong viscosity. This type of silt exhibits poor particle size distribution, high plasticity, and slow consolidation and drainage, making conventional resource utilization methods such as brick making, block production, or gravel utilization difficult. Therefore, a more economical and reasonable approach is to utilize the natural gullies surrounding the reservoir area to concentrate and store the dredged silt, constructing silt dams to impound it and allow the silt to gradually solidify within the dams, forming silt-rich land. This method is convenient to construct and has low cost, and has already been applied in small watershed management.

[0004] Traditional silt-retention dam construction typically relies on natural materials such as gravel or boulders for filling. However, these materials are difficult to obtain locally in the Loess Plateau region, often requiring quarrying and long-distance transportation, resulting in high project costs, long construction periods, and potential ecological damage. This is particularly pronounced in remote rural areas. Therefore, there is an urgent need to develop a composite structure and construction method that addresses the characteristics of reservoir dredging in the Loess Plateau, fully utilizes dredged silt for dam construction, and balances dam stability and ecological adaptability, in order to improve the safety, durability, and ecological benefits of silt-retention dams. Summary of the Invention

[0005] The purpose of this invention is to provide a silt-stabilizing dam structure and construction method based on composite reinforcement, so as to achieve efficient resource utilization of dredged silt and improve the stability, seepage prevention performance and ecological adaptability of the dam body.

[0006] To achieve the above objectives, the present invention provides a silt-stabilizing dam structure based on composite reinforcement, comprising:

[0007] The main body of the silt-retention dam is constructed by layering artificial aggregates that have undergone solidification, crushing, and screening.

[0008] Geomembrane, laid on the water-facing slope and the top of the silt-retaining dam body;

[0009] Geotextile bags are laid on the back slope and top of the main body of the silt-retaining dam;

[0010] Geogrids are laid in layers inside the main body of the silt-retaining dam, and the geotextile bags on the back slope are reinforced by wrapping them in reverse.

[0011] An eco-bag is placed on the outside of the geotextile bag;

[0012] A reverse-filter drainage layer is installed at the toe of the water-facing slope of the main body of the silt-retaining dam;

[0013] The dredged silt was backfilled and constructed on the backwater side of the main body of the silt-retaining dam.

[0014] Preferably, the artificial aggregate is formed by solidifying dredged sludge to form solidified sludge, followed by crushing and multi-stage screening. The compaction degree of the artificial aggregate is not less than 90%, the maximum particle size is 30cm to 80cm, and the coefficient of uniformity C is low. u Greater than 5.

[0015] Preferably, the geomembrane is a high-density polyethylene geomembrane with a thickness of 0.8mm to 1.5mm; when the geomembrane is laid, the overlap width is not less than 30cm and it is connected by hot welding; the edge of the geomembrane is overlapped and fixed with the geogrid wrapped around the top of the dam, the overlap length is 30cm to 50cm, and it is fixed with anchor nails.

[0016] Preferably, the geogrid is laid in layers inside the silt-retention dam body with a layer spacing of 1.0m to 2.0m. The geogrid extends beyond the silt-retention dam body at the back slope end to reinforce the geotextile bag by wrapping it back. The overlap length between the reserved section after wrapping and the geogrid laid inside the silt-retention dam body is not less than 50cm.

[0017] Preferably, the geotextile bag is filled with excavated soil with a compaction degree of not less than 90%; the ecological bag is filled with vegetative nutrient soil, which contains seeds of grass, leguminous or drought-resistant shrubs.

[0018] Preferably, the solidified sludge is obtained by mixing dredged sludge with an industrial solid waste solidifying agent at a dosage of 30-60 kg / m³ and then curing for 72 hours; the industrial solid waste solidifying agent is one or more of fly ash, blast furnace slag powder, steel slag powder, lime, desulfurized gypsum, and phosphogypsum.

[0019] Preferably, the reverse filter drainage layer is composed of crushed stone or gravel with a particle size of 5mm to 30mm.

[0020] This invention also provides a dam construction method based on a composite reinforced silt-stabilizing dam structure, comprising the following steps:

[0021] S1. Mix the reservoir dredged sludge with an industrial solid waste solidifying agent and stir for 72 hours to prepare solidified sludge.

[0022] S2. The solidified sludge is crushed and screened in multiple stages to prepare artificial aggregate;

[0023] S3. Carry out site leveling and dam foundation treatment, and lay a reverse filter drainage layer in the toe area of ​​the water-facing slope;

[0024] S4. Fill the artificial aggregate in the dam foundation to the height of the reverse filter drainage layer and compact it;

[0025] S5. Lay the first layer of geogrid on the compacted artificial aggregate and reserve the reverse wrapping length at the back slope end.

[0026] S6. Lay and compact geotextile bags at the back slope end, and use the reserved geogrid for reverse wrapping and fixation. At the same time, lay ecological bags on the outside of the geotextile bags.

[0027] S7. The artificial aggregate is filled in layers above the geogrid and inside the geobag and then compacted.

[0028] S8. Repeat steps S5 to S7 until the dam reaches the designed height.

[0029] S9. Lay geomembrane on the top of the dam and the water-facing slope and secure it by overlapping.

[0030] S10. Lay geotextile bags on top of the geomembrane and compact them, then lay ecological bags to complete the dam construction.

[0031] Preferably, the compaction degree after filling artificial aggregate in steps S4 and S7 is not less than 90%.

[0032] Preferably, the dam construction method is applicable to ecological management and dam reinforcement projects in loess gully areas, reservoir areas, or reservoir siltation dams.

[0033] Compared with the prior art, the present invention has the following advantages and technical effects:

[0034] 1. The silt-stabilizing dam structure based on composite reinforcement provided by this invention uses reservoir dredged silt as the main raw material of the dam body, realizing the efficient resource utilization of dredged silt and avoiding the high cost and ecological damage caused by traditional sand and gravel material mining and long-distance transportation, and has good economic and environmental benefits.

[0035] 2. This invention, by laying geogrids in layers within the dam body, installing geotextile bags on the downstream slope, and setting a reverse filter drainage layer at the toe of the slope, forms a highly efficient stress transfer and anti-sliding constraint system, significantly improving the overall stability of the dam. Simultaneously, the geomembrane on the upstream slope and dam crest effectively prevents seepage, while the reverse filter drainage layer at the toe reduces the phreatic line and seepage pressure, thereby improving the dam's seepage prevention and drainage performance. This structure also exhibits good ecological adaptability, employing a slope protection method combining ecological bags and local vegetation, balancing structural protection and ecological restoration, and adapting to the unique environment of alternating drought and heavy rainfall in the Loess gully region. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the composite reinforced silt-stabilizing dam structure of the present invention;

[0038] Figure 2 This is a schematic diagram of the overlap between the geomembrane and the geogrid of the present invention;

[0039] Figure 3 This is a schematic diagram of the geogrid wrapped around the geotextile bag according to the present invention;

[0040] In the diagram: 1. Main body of the silt-retention dam; 2. Geomembrane; 3. Geotextile bag; 4. Geogrid; 5. Ecological bag; 6. Reverse filter drainage layer; 7. Dredged silt; 9. Artificial aggregate; 11. Anchor nail; 12. Reserved section. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] like Figures 1 to 3 As shown, the present invention provides a silt-stabilizing dam structure based on composite reinforcement, comprising:

[0043] The main body of the silt-retention dam 1 is constructed by layering artificial aggregate 9, which has undergone solidification, crushing, and screening.

[0044] Geomembrane 2 is laid on the water-facing slope and the top of the silt-retaining dam body 1;

[0045] Geotextile bags 3 are laid on the back slope and top of the main body 1 of the silt-retaining dam;

[0046] Geogrid 4 is laid in layers inside the main body 1 of the silt-retaining dam and the geotextile bags 3 at the back slope are reinforced by wrapping them in reverse.

[0047] Ecological bag 5 is placed on the outside of geotextile bag 3;

[0048] The reverse filter drainage layer 6 is set in the water-facing slope toe area of ​​the silt-retaining dam body 1;

[0049] 7 dredged silt was backfilled and constructed on the backwater side of the main body of the silt-retaining dam 1.

[0050] Further optimization of the scheme: Artificial aggregate 9 is formed by solidifying dredged silt 7 into solidified silt, followed by crushing and multi-stage screening. The compaction degree of artificial aggregate 9 is not less than 90%, the maximum particle size is 30cm to 80cm, and the uniformity coefficient C is not less than 90%. u Greater than 5.

[0051] Further optimization of the scheme: Geomembrane 2 is a high-density polyethylene impermeable membrane with a thickness of 0.8mm to 1.5mm; when laying geomembrane 2, the overlap width is not less than 30cm and it is connected by hot welding; the edge of geomembrane 2 is overlapped and fixed with the geogrid 4 wrapped around the top of the dam, the overlap length is 30cm to 50cm, and it is fixed with anchor nails 11.

[0052] Further optimization of the scheme: the geogrid 4 is laid in layers inside the silt-retaining dam body 1 with a layer spacing of 1.0m to 2.0m. The geogrid 4 extends beyond the silt-retaining dam body 1 at the back slope end to reinforce the geotextile bag 3 by wrapping it back. The overlap length between the reserved section 12 after wrapping and the geogrid 4 laid inside the silt-retaining dam body 1 is not less than 50cm.

[0053] The plan was further optimized by filling the geotextile bag 3 with excavated soil on site, with a compaction degree of not less than 90%; and filling the ecological bag 5 with vegetative soil, which contains seeds of grass, legume or drought-resistant shrubs.

[0054] Further optimization of the scheme: solidified sludge is obtained by mixing dredged sludge 7 with an industrial solid waste solidifying agent at a dosage of 30-60 kg / m³ and then curing for 72 hours; the industrial solid waste solidifying agent is one or more of fly ash, blast furnace slag powder, steel slag powder, lime, desulfurized gypsum, and phosphogypsum.

[0055] Further optimization of the scheme: the reverse filter drainage layer 6 is composed of crushed stone or gravel with a particle size of 5mm to 30mm.

[0056] This invention also provides a dam construction method based on a composite reinforced silt-stabilizing dam structure, comprising the following steps:

[0057] S1. Mix the reservoir dredged sludge 7 with an industrial solid waste solidifying agent and stir for 72 hours to prepare solidified sludge.

[0058] S2. The solidified sludge is crushed and screened in multiple stages to prepare artificial aggregate 9;

[0059] S3. Carry out site leveling and dam foundation treatment, and lay a reverse filter drainage layer 6 in the toe area of ​​the water-facing slope;

[0060] S4. Fill the dam foundation with artificial aggregate 9 to the height of the reverse filter drainage layer 6 and compact it;

[0061] S5. Lay the first layer of geogrid 4 on the compacted artificial aggregate 9, and reserve the reverse wrapping length at the back slope end.

[0062] S6. Lay and compact geotextile bags 3 on the back slope end, and use the reserved geogrid 4 for reverse wrapping and fixing. At the same time, lay ecological bags 5 on the outside of geotextile bags 3.

[0063] S7. Artificial aggregate 9 is filled in layers above the geogrid 4 and inside the geobag 3 and then compacted.

[0064] S8. Repeat steps S5 to S7 until the dam reaches the designed height.

[0065] S9. Lay geomembrane 2 on the top of the dam body and the water-facing slope and fix it by overlapping;

[0066] S10. Lay geotextile bags 3 on top of geomembrane 2 and compact them, then lay ecological bags 5 to complete the dam construction.

[0067] The scheme was further optimized so that the compaction degree after filling artificial aggregate 9 in steps S4 and S7 was not less than 90%.

[0068] The scheme has been further optimized, and the dam construction method is applicable to the ecological management and dam reinforcement projects of loess gully areas, reservoir areas, or reservoir siltation dams.

[0069] Example

[0070] like Figure 1 As shown, the core of the silt-retention dam structure provided by this invention is the use of solidified reservoir dredged silt 7 as the dam construction material. In specific implementation, the dredged silt 7 is first mixed with an industrial solid waste solidifying agent (such as fly ash, slag powder, etc.) at a dosage of 50 kg / m³, and cured for 72 hours to form solidified silt. Subsequently, the solidified silt is crushed and subjected to multi-stage sieving to prepare particles with a maximum particle size of approximately 60 cm and good gradation (C...). u =6) artificial aggregate 9.

[0071] During dam construction, the site is first leveled and the dam foundation is treated. A reverse-filter drainage layer composed of 5mm-30mm crushed stone is laid at the toe of the water-facing slope. Then, layered filling begins.

[0072] Artificial aggregate 9 was filled into the dam foundation to the height of the reverse filter drainage layer 6, and compacted to a compaction degree of 92%. Then, the first layer of geogrid 4 was laid, with a layer spacing of approximately 1.6m, and sufficient length was reserved at the back slope end. A layer of two rows of geotextile bags 3 was laid and compacted at the back slope end, with the geotextile bags 3 filled with excavated soil. The geotextile bags 3 were reinforced by inverting the reserved section 12 of the geotextile bag 4, with an overlap length of 50cm between the inverted reserved section 12 and the lower geogrid 4. Simultaneously, a row of ecological bags 5 was laid on the outside of the geotextile bags 3, filled with nutrient soil mixed with local drought-resistant plant seeds.

[0073] Above the geogrid 4 and inside the geotextile bag 3, continue to fill artificial aggregate 9 in layers and compact it. Repeat this cycle of "laying geogrid - filling aggregate - filling geotextile bags - laying eco-bags" until the dam reaches the design height.

[0074] After the dam body is filled, a 1.0mm thick high-density polyethylene geomembrane is laid on the dam crest and the water-facing slope. Figure 2 As shown, the geomembrane 2 has an overlap width of 30cm and is connected by hot welding. Its edge overlaps with the geogrid 4 wrapped around the dam top for a length of 40cm and is fixed with U-shaped anchors 11 to form a reliable seepage prevention system. Finally, geotextile bags 3 are laid and compacted on the dam top and water-facing slope above the geomembrane 2, and then ecological bags 5 are laid to complete the construction of the entire dam.

[0075] This invention successfully transforms difficult-to-treat dredged silt into an effective resource for dam construction through an integrated technology of "silt solidification-composite reinforcement-ecological protection," creating a stable, seepage-proof, and eco-friendly silt-retaining dam structure that is particularly suitable for the ecological environment and engineering conditions of the Loess Plateau region.

[0076] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite reinforced based silt stabilization earth dam structure, characterized by, The application relates to a silt dam, which comprises the following components: a silt dam body (1) formed by layering artificial aggregates (9) after solidification, crushing and screening treatment; a geomembrane (2) laid on the water-facing slope and the top of the silt dam body (1); a geotextile bag (3) laid on the water-avoiding slope and the top of the silt dam body (1); a geogrid (4) layer-laid in the silt dam body (1) and used for reinforcing the geotextile bag (3) on the water-avoiding slope; an ecological bag (5) arranged outside the geotextile bag (3); a filter drainage layer (6) arranged at the foot of the water-facing slope of the silt dam body (1); and backfill dredged silt (7) filled on the water-avoiding side of the silt dam body (1). The geomembrane (2) is a high-density polyethylene impermeable membrane with a thickness of 0.8mm-1.5mm; when the geomembrane (2) is laid, the overlapping width is not less than 30cm, and the geomembrane (2) is connected by hot welding; the edge of the geomembrane (2) is fixedly connected with the geogrid (4) on the top by overlapping with a length of 30cm-50cm, and the overlapping is fixed by anchor nails (11). The geogrid (4) is layer-laid in the silt dam body (1) with a layer distance of 1.0m-2.0m, and the geogrid (4) is laid on the water-avoiding slope to exceed the silt dam body (1) so as to reinforce the geotextile bag (3), and the overlapping length of the reserved section (12) after the reinforcement and the geogrid (4) laid in the silt dam body (1) is not less than 50cm. The geotextile bag (3) is filled with on-site excavated soil with a compaction degree not less than 90%, and the ecological bag (5) is filled with plant nutrient soil mixed with seeds of grass family, legume family or drought-resistant shrub. The solidified silt is obtained by mixing the dredged silt (7) with an industrial solid waste type solidifying agent at a mixing amount of 30-60kg / m3 and curing for 72 hours; the industrial solid waste type solidifying agent is one or more of fly ash, blast furnace slag powder, steel slag powder, lime, desulfurization gypsum and phosphor gypsum. The filter drainage layer (6) is composed of gravel or sand with a particle size of 5mm-30mm. The application further discloses a preparation method of the silt dam, which comprises the following steps: S1, mixing and stirring the reservoir dredged silt (7) with an industrial solid waste type solidifying agent, preliminarily solidifying for 72 hours to prepare solidified silt; S2, crushing and multi-stage screening the solidified silt to prepare artificial aggregates (9); S3, carrying out site leveling and dam foundation treatment and laying a filter drainage layer (6) at the foot of the water-facing slope; S4, filling the artificial aggregates (9) on the dam foundation to the height of the filter drainage layer (6) and rolling; S5, laying a first layer of geogrid (4) on the rolled artificial aggregates (9) and reserving a back-packing length at the water-avoiding slope end; S6, laying and compacting the geotextile bag (3) at the water-avoiding slope end, back-packing by the reserved geogrid (4) and simultaneously laying ecological bags (5) outside the geotextile bag (3); S7, layer-filling the artificial aggregates (9) on the geogrid (4) and inside the geotextile bag (3) and rolling. ​ 2. The composite reinforced based silt stabilization earth dam structure as claimed in claim 1 wherein, The artificial aggregate (9) is formed by solidifying dredged silt (7) into solidified silt, and then crushing and multi-stage screening, the compaction degree of the artificial aggregate (9) is not less than 90%, the maximum particle size is 30cm-80cm, and the non-uniformity coefficient C u is greater than 5.

3. The composite reinforced based silt stabilization earth dam structure as claimed in claim 1 wherein, ​ 4. The composite reinforced based silt stabilization levee structure as claimed in claim 1 wherein, ​ 5. The composite reinforced based silt stabilization levee structure as claimed in claim 1 wherein, ​ 6. The composite reinforced based silt stabilization levee structure as claimed in claim 2, wherein, ​ 7. The composite reinforced based silt stabilization levee structure as claimed in claim 1 wherein, ​ 8. A method of building a dike of a composite reinforced silt stabilized dike structure according to any one of claims 1-7, characterized in that ​ ​ ​ ​ ​ ​ ​ ​ S8, repeat steps S5 to S7 until the dam body reaches the design height; S9, lay the geomembrane (2) on the top and the water-facing slope of the dam body and perform lap joint fixing; S10, lay the geotextile bag (3) above the geomembrane (2) and compact, and then lay the ecological bag (5), to complete dam building.

9. The damming method of claim 8, wherein, The compaction degree after filling the artificial aggregate (9) in steps S4 and S7 is not less than 90%.

10. The damming method of claim 8, wherein, The dam building method is suitable for ecological management and dam body reinforcement engineering of loess gully area, reservoir area or reservoir silt dam.

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