Strip Mine Dump Sponge Structure for Water Retention
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Solution Overview
Problem
Large-scale strip mine dumps in semi-arid loess areas face challenges in ecological reconstruction due to uneven sedimentation, severe water erosion, and low vegetation coverage, as existing methods overlook the layered structure and physical properties of the soil, making effective water retention and vegetation restoration difficult.
Innovation Solution
A three-layered sponge ecological structure comprising a water-resisting layer, a water-containing layer, and a topsoil ecological layer, where the water-resisting layer is formed of compacted sand, gravel, and fly ash, the water-containing layer is made of compacted sand, soil, and fly ash, and the topsoil layer is suitable for vegetation growth, allowing for dynamic water accumulation and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If mechanical transportation and compaction are applied to increase dump capacity, then the capacity of the dump is improved, but the layered structure and physical properties of covering soil are degraded
Solution Approach 1:
The patent divides the covering soil into three distinct functional layers: a water-resisting layer (100-200cm thick) at the bottom, a water-containing layer (150-250cm thick) in the middle, and a topsoil ecological layer (40-60cm thick) at the top. This segmentation allows each layer to perform its specific function while maintaining overall structural stability, resolving the contradiction between dump capacity and soil structure preservation.
Solution Approach 2:
The patent applies local quality by giving different physical properties to different layers: the water-resisting layer has low permeability (0.35-0.7m/d) to prevent water loss, the water-containing layer has moderate permeability (10-20m/d) to store and regulate water, and the topsoil layer has high organic matter content to support vegetation. This localized optimization resolves the contradiction by preserving functional structure while accommodating large-scale dumping.
2Strength
If mechanical compaction is used to create hard surface layer, then the structural stability is improved, but water retention capability is worsened
Solution Approach 1:
The patent segments the soil structure into three layers with different compaction degrees and permeability characteristics. The water-resisting layer is heavily compacted (1200-1400 KPa) to provide structural stability, while the water-containing layer is lightly compacted (800-900 KPa) to maintain water retention, and the topsoil layer is left loose for vegetation. This segmentation resolves the contradiction between structural stability and water retention.
Solution Approach 2:
The patent applies local quality by creating a water-resisting layer with specific compaction (1200-1400 KPa) and low permeability (0.35-0.7m/d) at the bottom for structural stability, while the water-containing layer above it has lower compaction (800-900 KPa) and higher permeability (10-20m/d) for water retention. This localized differentiation resolves the contradiction between hard surface stability and water retention capability.
3Reliability
If fly ash with specific particle size is used in water-resisting layer, then the water resistance is improved, but the material cost and availability constraints are worsened
Solution Approach 1:
The patent utilizes fly ash, a waste product from coal-fired power plants, to construct the water-resisting layer. By specifying particle size requirements (17-40 μm, averaging 30 μm) and chemical composition (SiO2, Al2O3, Fe2O3, CaO), the patent transforms an available waste material into a functional engineering material, improving water resistance while leveraging existing industrial byproducts to reduce material costs and availability constraints.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The structure significantly improves ecological reconstruction by enhancing water retention, promoting vegetation growth, and reducing soil and water loss, achieving better vegetation diversity, biomass, and ecosystem stability, while effectively utilizing water resources.
Implementation Method 1
When there is much surface water, the water will infiltrate and remain at this layer
Implementation Method 2
root system will root downward to this layer to absorb and transfer the water
Implementation Method 3
The water-resisting layer is formed of sand and gravel, soil, and fly ash that have been subjected to compaction
Data Source
AI summary
An ecological reconstructed sponge structure of a strip mine dump includes a three-layered sponge ecological structure arranged on a groundmass layer of the dump. From bottom to top, the three-layer sponge ecological structure comprises a water-resisting layer, a water-containing layer and a topsoil ecological layer. A thickness of the water-resisting layer is 100˜200 cm, a permeability coefficient of the water-resisting layer is 0.35˜0.7 m/d, and a degree of compaction is 1200˜1400 KPa. A thickness of the water-containing layer is 150˜250 cm, a permeability coefficient of the water-containing layer is 10˜20 m/d, and a degree of compaction is 800˜900 KPa. A thickness of the topsoil ecological layer is 40˜60 cm. Soil layer thicknesses and water content may be monitored through a ground penetrating radar.