Layered backfilling and ecological regreening system for flow-state solidified soil of anchoring ditch of refuse landfill

Abstract

The invention discloses a layered backfilling and ecological regreening system for flow-state solidified soil of an anchoring ditch of a refuse landfill. The layered backfilling and ecological regreening system comprises a muck (weathered rock) pretreatment unit, a flow-state solidified soil production unit, an ecological regreening unit, a pumping backfilling unit and an intelligent regulation and control unit. According to the system, the structure reinforcing function and the ecological restoration function are successfully integrated, and a brand-new and sustainable engineering residue soil (weathered rock) resource utilization and ecological backfill solution is provided.

Description

Technical Field

[0001] This invention relates to the technical field of waste gas treatment, and in particular to a layered backfilling and ecological restoration system for anchoring trenches in landfills using fluidized solidified soil. Background Technology

[0002] Currently, in landfill engineering, there are two main traditional backfilling methods for anchoring trenches of HDPE geomembrane: Plain soil backfilling: This method uses the excavated undisturbed soil for backfilling and compaction. While cost-effective, it has significant drawbacks: sharp stones can easily puncture or scratch the HDPE membrane during compaction, causing the impermeable layer to fail; additionally, the low density of the plain soil (typically less than 1.6 g / cm³) results in insufficient self-weight to provide effective anchoring force, potentially leading to displacement under stress. In short, it is cost-effective, but compaction easily punctures the membrane, and its low density and insufficient anchoring force contribute to its disadvantages.

[0003] Concrete backfilling: C20 or higher grade concrete is used for backfilling. This method provides reliable anchoring, but it is costly and an overkill. The high strength of concrete is not necessary in this anchoring scenario, resulting in material waste and increased economic costs. In other words, it provides reliable anchoring, but is costly, has excessive performance, and is uneconomical.

[0004] Existing technologies lack a comprehensive solution that can provide reliable anchoring and protection of membrane materials, while also being economical, environmentally friendly, and enabling ecological restoration. Summary of the Invention In view of the shortcomings of the prior art, the technical problem solved by the present invention is to provide an integrated, eco-friendly landfill anchoring trench backfilling system. This system can achieve the following objectives: 1. Secure anchoring: Provides superior anchoring force compared to plain soil, and the construction process involves zero compaction, absolutely protecting the HDPE membrane.

[0005] 2. Resource recycling: 100% utilization of engineering waste soil (weathered rock) and on-site wastewater to achieve "using local materials and turning waste into treasure".

[0006] 3. Ecological restoration: Through a unique structural layer design, it solves the problems of cracking and weathering on the exposed surface of solidified soil, and realizes the immediate restoration of vegetation on the surface of the anchoring trench, beautifying the environment.

[0007] 4. Economical and efficient: The cost is far lower than that of concrete, and the construction efficiency is improved through an automated and integrated system.

[0008] To address the aforementioned technical problems, this invention provides a layered backfilling and ecological restoration system for fluidized solidified soil in landfill anchoring trenches, comprising a slag (weathered rock) pretreatment unit, a fluidized solidified soil production unit, an ecological restoration unit, a pumping backfilling unit, and an intelligent control unit.

[0009] As a preferred embodiment of the above technical solution, the landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system provided by the present invention further includes some or all of the following technical features: As an improvement to the above technical solution, the slag (weathered rock) pretreatment unit includes a crusher and a screening machine (mainly a wind-powered sorting device), which is used to crush and screen the engineering weathered rock slag excavated from the anchoring trench, control the particle size to below 2cm, and achieve efficient separation of light impurities in the slag.

[0010] As an improvement to the above technical solution, the fluidized solidified soil production unit includes the introduction of an AI-based proportioning optimization system, which dynamically adjusts the water-to-solid ratio and the amount of solidifying agent according to the composition of the slag and soil. The optimization system first mixes recycled aggregate with water at a water-to-solid ratio of more than 48% to form a slurry, and controls the amount of solidifying agent added by monitoring the density of the slurry. Then, solid waste-based cementitious PHC solidifying agent is added and mixed to produce high fluidized solidified soil with a density controlled above 1.7 g / cm³, a 28-day strength of not less than 0.4 MPa, and a slump spread > 300 mm.

[0011] As an improvement to the above technical solution, the ecological restoration unit includes a small-scale dedicated planting soil mixing station for mixing some of the screened fine-grained recycled aggregate, solidifying agent (dry basis addition ratio of 2%), and plant nutrients (plant root promoter and water-retaining polymer material) to prepare ecological planting soil that can be used for direct planting; and the mixing station is equipped with a microbial agent addition device to enhance the fertility and biological activity of the ecological planting soil.

[0012] As an improvement to the above technical solution, the pumping backfilling unit includes a mud pump and a conveying pipeline, the inlet of which is connected to the outlet of the fluidized solidified soil production unit, for pumping the fluidized solidified soil into the anchoring trench; a variable frequency controlled mud pump is used to achieve precise adjustment of flow rate and pressure.

[0013] As an improvement to the above technical solution, the water supply system preferentially uses reclaimed water that has been treated on-site using a "biochemical treatment + reverse osmosis (RO)" process to meet the "Standard for Water Used in Concrete" (JGJ 63-2006).

[0014] As an improvement to the above technical solution, the intelligent control unit includes a stress sensor, a data acquisition system, and a control platform, which monitors the backfill status in real time and provides feedback to adjust construction parameters.

[0015] As an improvement to the above technical solution, the backfill material in the anchoring trench adopts a functional layered structure: Bottom anchor body: From the bottom of the trench to 15cm from the top of the trench, the fluid solidified soil is pumped backfilled, with a dry-base solidification agent addition ratio of 10%, which mainly provides the main anchor weight and friction force; Intermediate reinforcement: From 15cm to 5cm from the top of the trench, a fluidized solidified soil is pumped backfilled, with a dry-base solidifying agent addition ratio of 15%, which plays a role in strengthening protection and preventing surface cracking and seepage. Surface Ecosystem: The top 5cm layer is made of ecological planting soil prepared by the ecological revegetation unit and is spread and leveled manually. This layer has low strength requirements, is rich in nutrients, and can be directly sown or laid with turf to achieve permanent revegetation and fundamentally solve the problems of cracking and weathering on exposed surfaces.

[0016] This invention also includes a construction method for a landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system as described in any of the above descriptions, comprising the following steps: Step 1. Pretreatment: The excavated slag (weathered rock) is crushed and screened in the slag pretreatment unit (1) to obtain recycled aggregate; Step 2. Preparation of main materials: Most of the recycled aggregate, water and curing agent are sent to the fluidized solidified soil production unit (2) to produce fluidized solidified soil with 10% and 15% admixtures; Step 3. Preparation of ecological soil: Take some fine-grained recycled aggregate, send it into the ecological restoration unit (9), add 2% solidifying agent and nutrients, and mix to form ecological planting soil; Step 4. Pumping backfill: First, use the pumping backfill unit (5) to pump the 10% admixture of fluidized solidified soil to the bottom of the backfill area to form the bottom anchor body (6); then switch to pumping the 15% admixture of fluidized solidified soil to form the middle reinforcement body (7). Step 5. Ecological construction: Finally, spread the ecological planting soil prepared in the ecological restoration unit (9) to the design elevation to form the surface ecological body (8), and immediately carry out sowing or turf laying.

[0017] This system successfully integrates structural reinforcement and ecological restoration functions, providing a new and sustainable solution for the resource utilization and ecological backfilling of engineering waste (weathered rock).

[0018] As an improvement to the above technical solution, the slag pretreatment unit (1) is a crusher and a screening machine; the fluidized solidified soil production unit (2) is a planetary mixer; the ecological restoration unit (9) is a small planting soil mixing station; and the pumping backfilling unit (5) is a mud pump.

[0019] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. High level of intelligence: Through real-time monitoring and feedback control, it enables precise construction and long-term performance monitoring of anchor trench backfilling.

[0020] 2. Superior material properties: The curing agent prepared using industrial solid waste is not only low in cost, but also has better mechanical properties and durability than traditional materials.

[0021] 3. Outstanding ecological benefits: Through the synergistic effect of microorganisms and plants, rapid ecological restoration and long-term stability of the anchoring trench surface are achieved.

[0022] 4. High resource utilization rate: The utilization rate of slag and wastewater reaches 100%, and the proportion of industrial solid waste in the solidifying agent exceeds 70%, resulting in significant environmental benefits.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, the following detailed description is provided in conjunction with preferred embodiments. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0025] Figure 1 This invention relates to a structural and process flow diagram of a landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system.

[0026] In the diagram: 1-Pre-treatment unit for slag (weathered rock) (crusher, screening machine); 2-Fluidized solidified soil production unit (planetary mixer); 3-Solidifying agent silo; 4-Water supply system; 5-Pumping backfill unit (slurry pump); 6-Bottom anchor (10% admixture); 7-Middle reinforcement (15% admixture); 8-Top layer ecology (ecological planting soil); 9-Ecological revegetation unit (small planting soil mixing plant). Detailed Implementation

[0027] The following detailed description of specific embodiments of the present invention is part of this specification. The principles of the present invention are illustrated through examples, and other aspects, features and advantages of the present invention will become apparent from this detailed description.

[0028] like Figure 1 As shown, the present invention is carried out by following these steps: 1. Pretreatment: The excavated slag (weathered rock) is crushed and screened by the slag pretreatment unit (1) (crusher and screening machine) to obtain recycled aggregate.

[0029] 2. Preparation of main materials: Most of the recycled aggregate, water and curing agent are fed into the fluidized solidified soil production unit (2) (planetary mixer) to produce fluidized solidified soil with two admixtures (10% and 15%).

[0030] 3. Preparation of ecological soil: Take some fine-grained recycled aggregate and send it into the ecological restoration unit (9) (small planting soil mixing station), add 2% solidifying agent and nutrients, and mix to form ecological planting soil.

[0031] 4. Pumping backfill: First, use the pumping backfill unit (5) (mud pump) to pump the 10% admixture of fluidized solidified soil to the bottom of the backfill area to form the bottom anchor body (6); then switch to pumping the 15% admixture of fluidized solidified soil to form the middle reinforcement body (7).

[0032] 5. Ecological construction: Finally, spread the ecological planting soil prepared in the ecological restoration unit (9) to the design elevation to form the surface ecological body (8), and immediately carry out sowing or turf laying.

[0033] This system successfully integrates structural reinforcement and ecological restoration functions, providing a new and sustainable solution for the resource utilization and ecological backfilling of engineering waste (weathered rock).

[0034] Example: A landfill in Danjiangkou City Project Overview: The anchoring trench in the Emergency I reservoir area of ​​the Danjiangkou City landfill is a typical manually excavated trench, designed with a depth of 3.0m, a top width of 2.5m, a bottom width of 1.5m, a slope ratio of 1:1.5, and a total length of 1200m. The original design used concrete backfill, but this presented problems such as high cost and difficulties in ecological restoration. A layered backfilling technology using fluidized solidified soil was adopted, combined with intelligent monitoring and ecological revegetation, achieving a dual improvement in both anchoring function and ecological benefits.

[0035] Construction steps: 1. Preparation: Site cleanup: Remove debris (gravel, plastic film fragments, etc.) from the anchoring trench, with an average cleaning depth of 0.3m and a recovery rate of ≥95%; The measurement and layout error is ≤±2cm to ensure accurate backfill boundary.

[0036] Materials preparation: Pre-treatment of excavated soil: 5000 m³ of weathered rock excavated from the anchoring trench is crushed and screened, with 92% of the particles having a diameter ≤2 cm and the moisture content controlled at 15%~18%; Curing agent ratio: 800t of PHC curing agent (dosage 10%~15%), added in layers of 10% for the bottom layer and 15% for the middle layer; Reclaimed water: Landfill leachate is treated by a "biochemical treatment + reverse osmosis" process, and the water quality meets the "Standard for Water Used in Concrete" (JGJ 63-2006), with a pH value of 7.2 and a suspended solids content of <50mg / L.

[0037] Equipment debugging: The mud pump flow rate accuracy is ±5% (10~15 m³ / h), and the pressure sensor error is ≤0.05 MPa. The smart sensors (stress, moisture content) are deployed at a density of 1 sensor per 5m, with a data acquisition frequency of 1 time per minute.

[0038] 2. Layered backfilling and data monitoring Bottom anchorage (0~1.5m): Pumping parameters: flow rate 15 m³ / h, pressure 0.3 MPa, pumping time 2 hours / segment (each segment length 10 m). Performance monitoring: Real-time monitoring of collapse spread, with an average value of 365mm (standard requirement >350mm). The 28-day unconfined compressive strength is 0.63 MPa (test report number HBCD-CXQD25000012), which meets the design requirements (≥0.4 MPa). Stress sensor feedback: The maximum stress within 72 hours after backfilling was 0.12 MPa, which is much less than the tensile strength of HDPE membrane (≥20 MPa), and the membrane was undamaged.

[0039] Intermediate reinforcement layer (1.5~2.95m): Pumping parameters: flow rate 10 m³ / h, pressure 0.5 MPa, pumping time 3 hours / segment; Performance monitoring: With the curing agent dosage increased to 15%, the 28-day strength reached 0.82 MPa; After 5 freeze-thaw cycles, the strength loss rate was 6.8% (<8%), and the water stability coefficient was 92%. The uniformity of stress distribution is improved, with the maximum stress difference ≤0.03MPa (0.05MPa for the bottom layer).

[0040] Surface ecosystem (2.95~3.0m): Paving parameters: Ecological revegetation soil thickness 5cm, compaction degree 0.92 (standard requirement ≥0.90); Performance monitoring: Porosity 18%, permeability coefficient 1.2×10 -4 cm / s, meeting the needs of vegetation growth; After the addition of microbial inoculants, the soil nitrogen content increased by 25% (from 0.12% to 0.15%) and the phosphorus content increased by 18% (from 0.08% to 0.095%).

[0041] 3. Intelligent monitoring and dynamic adjustment Stress sensors (accuracy ±0.01MPa), moisture content sensors (accuracy ±1%), and displacement sensors (accuracy ±0.1mm) are installed in layers within the anchoring trench, with a monitoring frequency of once per minute, and the data is transmitted to the cloud platform in real time.

[0042] Stress feedback system: Real-time monitoring of backfill stress; when the stress in a certain area exceeds 0.1 MPa, the pumping flow rate is automatically reduced by 20%. Three flow rate adjustments were triggered during construction to avoid localized stress concentration.

[0043] Moisture content control: The sensor monitors the moisture content, and when it deviates from the optimal value (18%~20%), the sprinkler system is automatically activated to replenish water; The total water replenishment volume is 120 m³, with a moisture content fluctuation range of ±1%.

[0044] 4. Ecological restoration and revegetation Vegetation growth: Sow a mixture of ryegrass and tall fescue seeds (3:1 ratio) at a rate of 30 g / m². Germination rate of 92% in 7 days and vegetation coverage of 95% in 30 days (standard requirement ≥90%). Root penetration depth: 12cm for ryegrass, 15cm for tall fescue, soil stabilization amount 1.3kg / m² (>design value 1.2kg / m²).

[0045] Erosion resistance: Under simulated rainfall (intensity 50 mm / h, lasting 2 hours), the surface soil loss was 1.8 kg / m² (< standard value 2 kg / m²). Rainwater infiltration depth ≤8cm, and no runoff erosion of the ditch was observed.

[0046] Microbial activity: The number of nitrogen-fixing bacteria increased from 10 5 CFU / g increased to 10 7 CFU / g, phosphate-solubilizing bacteria count from 10 4 CFU / g increased to 10 6 CFU / g; Soil enzyme activity (urease, phosphatase) increased by 40%, promoting nutrient cycling.

[0047] 5. Long-term monitoring system and its application effects Within 12 months after construction, the internal structure of the backfill will be scanned monthly using ground-penetrating radar to detect changes in porosity; soil samples will be collected quarterly to test compressive strength and verify durability.

[0048] Anchoring performance: Displacement of the trench was monitored for 12 months after backfilling, with a maximum displacement of 1.8 mm (<5 mm, the design allowable value). HDPE membrane integrity test: No damage points were found when scanning with an electrical discharge machine, and the interfacial bonding strength between the membrane and the backfill was 0.15 MPa.

[0049] Ecological benefits: Vegetation cover reduced dust by 90%, and PM10 concentration dropped from 1.2 mg / m³ during the construction period to 0.15 mg / m³. Carbon sequestration estimate: Approximately 120 tons of CO2 are fixed annually (calculated based on vegetation biomass).

[0050] Table 1. Economic Comparison

[0051] In summary, this invention is a comprehensive solution that provides reliable anchoring and protection of membrane materials, is economical and environmentally friendly, and can achieve ecological restoration.

[0052] All the raw materials listed in this invention, as well as the upper and lower limits and ranges of the raw materials and the upper and lower limits and ranges of the process parameters (such as temperature, time, etc.), can realize this invention. Examples are not listed one by one here.

[0053] The above description is merely a preferred embodiment of the present invention, and should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A layered backfilling and ecological revegetation system for anchoring trenches in landfills using fluidized solidified soil, characterized in that: It includes a slag (weathered rock) pretreatment unit, a fluidized solidified soil production unit, an ecological restoration unit, a pumping backfill unit, and an intelligent control unit.

2. The landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system as described in claim 1, characterized in that: The slag (weathered rock) pretreatment unit includes a crusher and a screening machine (mainly a wind-powered sorting device), which is used to crush and screen the engineering weathered rock slag excavated from the anchoring trench, control the particle size to below 2cm, and achieve efficient separation of light impurities in the slag.

3. The landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system as described in claim 1, characterized in that: The fluidized solidified soil production unit includes an AI-based proportioning optimization system that dynamically adjusts the water-to-solid ratio and the amount of solidifying agent based on the composition of the slag and soil. The optimization system first mixes recycled aggregate with water at a water-to-solid ratio of 48% or higher to form a slurry, and controls the amount of solidifying agent added by monitoring the density of the slurry. Then, solid waste-based cementitious PHC solidifying agent is added and mixed to produce high-fluidity solidified soil with a density controlled above 1.7 g / cm³, a 28-day strength of not less than 0.4 MPa, and a slump spread > 300 mm.

4. The landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system as described in claim 1, characterized in that: The ecological restoration unit includes a small-scale dedicated planting soil mixing station for mixing a portion of the screened fine-grained recycled aggregate, a solidifying agent (dry basis addition ratio of 2%), and plant nutrients (plant root promoter and water-retaining polymer material) to prepare ecological planting soil that can be used for direct planting; and the mixing station is equipped with a microbial agent addition device to enhance the fertility and biological activity of the ecological planting soil.

5. The landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system as described in claim 1, characterized in that: The pumping backfilling unit includes a mud pump and a conveying pipeline. Its inlet is connected to the outlet of the fluidized solidified soil production unit, which is used to pump the fluidized solidified soil into the anchoring trench. The mud pump is frequency-controlled to achieve precise regulation of flow rate and pressure.

6. The landfill anchoring trench fluidized solidified soil layered backfilling and ecological restoration system as described in claim 1, characterized in that: The water supply system preferentially uses reclaimed water that has been treated on-site using a "biochemical treatment + reverse osmosis (RO)" process to meet the "Standard for Water Used in Concrete" (JGJ 63-2006).

7. The landfill anchoring trench fluidized solidified soil layered backfilling and ecological revegetation system as described in claim 1, characterized in that: The intelligent control unit includes a stress sensor, a data acquisition system, and a control platform, which monitors the backfill status in real time and provides feedback to adjust construction parameters.

8. The landfill anchoring trench fluidized solidified soil layered backfilling and ecological revegetation system as described in claim 1, characterized in that: The backfill material in the anchoring trench adopts a functional layered structure: Bottom anchor body: From the bottom of the trench to 15cm from the top of the trench, the fluid solidified soil is pumped backfilled, with a dry-base solidification agent addition ratio of 10%, which mainly provides the main anchor weight and friction force; Intermediate reinforcement: From 15cm to 5cm from the top of the trench, a fluidized solidified soil is pumped backfilled, with a dry-base solidifying agent addition ratio of 15%, which plays a role in strengthening protection and preventing surface cracking and seepage. Surface Ecosystem: The top 5cm layer is made of ecological planting soil prepared by the ecological revegetation unit and is spread and leveled manually. This layer has low strength requirements, is rich in nutrients, and can be directly sown or laid with turf to achieve permanent revegetation and fundamentally solve the problems of cracking and weathering on exposed surfaces.

9. A construction method for a landfill anchoring trench fluidized solidified soil layered backfilling and ecological revegetation system as described in any one of claims 1-8, characterized in that, It includes the following steps: Step 1. Pretreatment: The excavated slag (weathered rock) is crushed and screened in the slag pretreatment unit (1) to obtain recycled aggregate; Step 2. Preparation of main materials: Most of the recycled aggregate, water and curing agent are sent to the fluidized solidified soil production unit (2) to produce fluidized solidified soil with 10% and 15% admixtures; Step 3. Preparation of ecological soil: Take some fine-grained recycled aggregate, send it into the ecological restoration unit (9), add 2% solidifying agent and nutrients, and mix to form ecological planting soil; Step 4. Pumping backfill: First, use the pumping backfill unit (5) to pump the 10% admixture of fluidized solidified soil to the bottom of the backfill area to form the bottom anchor body (6); then switch to pumping the 15% admixture of fluidized solidified soil to form the middle reinforcement body (7). Step 5. Ecological construction: Finally, spread the ecological planting soil prepared in the ecological restoration unit (9) to the design elevation to form the surface ecological body (8), and immediately carry out sowing or turf laying. This system successfully integrates structural reinforcement and ecological restoration functions, providing a new and sustainable solution for the resource utilization and ecological backfilling of engineering waste (weathered rock).

10. The construction method of the landfill anchoring trench fluidized solidified soil layered backfilling and ecological revegetation system as described in claim 9, characterized in that: The slag pretreatment unit (1) is a crusher and a screening machine; the fluidized solidified soil production unit (2) is a planetary mixer; the ecological restoration unit (9) is a small planting soil mixing station; and the pumping backfill unit (5) is a mud pump.

Images