Reconstruction structure and method of frozen soil layer in alpine mining area
By constructing a permafrost layer reconstruction structure in high-altitude and cold mining areas, including a water-blocking layer, a water-retaining layer, a vegetation layer, and a heat-insulating and permeable layer, the problem of permafrost layer damage was solved, and the effective reconstruction of the permafrost layer and improvement of the ecological environment were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING FORESTRY UNIVERSITY
- Filing Date
- 2024-06-11
- Publication Date
- 2026-07-21
AI Technical Summary
Mining activities in high-altitude and cold mining areas have damaged the original soil structure, disrupting the balance of the permafrost layer, reducing its water conservation and transport functions, and causing vegetation degradation. Traditional backfill coal gangue soil profiles have strong heat absorption capacity and poor permeability, making it difficult to form seasonal permafrost.
The frozen soil layer is reconstructed using a structure consisting of a water-blocking layer, a water-retaining layer, a vegetation layer, and a heat-insulating and permeable layer. The water-blocking layer is composed of small-diameter coal gangue and a water-blocking agent, the water-retaining layer is composed of medium-diameter coal gangue and a water-retaining agent, the vegetation layer is composed of organic fertilizer and seed residue, and the heat-insulating and permeable layer is composed of large-diameter coal gangue and coconut fiber vegetation blanket. The reconstruction of the frozen soil layer is achieved through a layered structure.
It has achieved effective reconstruction of the permafrost layer, improved the soil's water retention capacity, heat insulation performance and water-blocking performance, promoted vegetation growth, and significantly improved the ecological environment of the high-altitude mining area.
Smart Images
Figure CN118648404B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ecological restoration, and more specifically, to a structure and method for reconstructing permafrost in high-altitude mining areas. Background Technology
[0002] The Qinghai-Tibet Plateau has the most extensive permafrost distribution area in my country. However, mining activities in high-altitude coal mines have disrupted the original soil structure and permafrost balance, causing damage to the permafrost, reducing its water conservation and transport functions, and leading to vegetation degradation. Traditional backfill coal gangue soil profiles have strong surface heat absorption capacity but also suffer from severe water infiltration and poor water retention and resistance, hindering the formation of seasonally frozen soil. Therefore, this study explores and innovates a near-natural reconstruction method for coal gangue soil profiles, providing support and guidance for permafrost reconstruction in high-altitude mining areas. This method has significant practical implications for permafrost reconstruction in future ecological restoration projects in high-altitude and adjacent regions. Summary of the Invention
[0003] The purpose of this invention is to provide a structure and method for reconstructing permafrost in high-altitude mining areas.
[0004] To achieve the objective of this invention, in a first aspect, this invention provides a reconstructed structure for permafrost in high-altitude mining areas, comprising, from bottom to top, a water-blocking layer, a water-retaining layer, a vegetation layer, and a heat-insulating and permeable layer.
[0005] The water-blocking layer is composed of coal gangue with a particle size of <0.5mm and a water-blocking agent; the water-blocking agent is polyacrylamide (PAM) or sodium bentonite.
[0006] The water-retaining layer is composed of coal gangue with a particle size of 0.5-2 mm and a water-retaining agent; the water-retaining agent is potassium polyacrylate.
[0007] The vegetation layer consists of compost soil with added organic fertilizer and seeds.
[0008] The heat-insulating and water-permeable layer is composed of coal gangue particles with a particle size of 2 to 10 mm, and the surface is covered with a layer of coconut fiber vegetation blanket.
[0009] Furthermore, the thickness of the water-blocking layer is 5–8 cm, and its compactness is 150–200 N / cm. 2 per m 3 Add 200g of water-blocking agent to the coal gangue.
[0010] Preferably, the water-blocking agent is a polyacrylamide (PAM) water-blocking agent, which is polymerized from high-molecular-weight polyacrylamide and appears as a white powder. Sodium-based bentonite can be used as a substitute, with montmorillonite as the main component, and it also appears as a white powder.
[0011] Furthermore, the thickness of the water-retaining layer is 30–40 cm, and its compactness is 100–150 N / cm. 2 per m 3 Add 200g of water-retaining agent to the coal gangue.
[0012] Preferably, the water-retaining agent is KSAP (Kita potassium salt water-retaining agent), which is composed of potassium polyacrylate and appears as white fine crystalline granules. It can be replaced by a superabsorbent polymer (SAP) water-retaining agent, whose main component is potassium polyacrylate and also appears as white fine crystalline granules.
[0013] Furthermore, the thickness of the heat-insulating and water-permeable layer is 3-5 cm, and it can be loosely laid, according to 200 g / m². 2 Lay out a coconut fiber vegetation blanket.
[0014] Secondly, the present invention provides the application of the structure in soil improvement and ecological restoration in high-altitude mining areas.
[0015] Thirdly, the present invention provides a method for reconstructing permafrost in high-altitude mining areas, comprising: (1) excavating a profile, screening coal gangue, and removing large-volume stones; (2) backfilling small-diameter coal gangue and adding a water-blocking agent (such as polyacrylamide or sodium bentonite) and compacting it after mixing; (3) backfilling medium-diameter coal gangue and adding a water-retaining agent (such as potassium polyacrylate) and compacting it after mixing; (4) backfilling slag soil with added organic fertilizer and seeds; (5) backfilling large-diameter coal gangue; and (6) laying coconut fiber vegetation blankets.
[0016] Furthermore, step (2) is performed on every m 3 Add 200g of polyacrylamide water-blocking agent to coal gangue with a particle size <0.5mm, mix well, and compact to a thickness of 5-8cm with a compaction degree of 150-200N / cm. 2 .
[0017] Furthermore, step (3) is performed on every m 3 Add 200g of potassium polyacrylate water-retaining agent to coal gangue with a particle size of 0.5-2mm, mix well, and compact to a thickness of 30-40cm with a compaction degree of 100-150N / cm. 2 .
[0018] Further, in step (5), backfill with coal gangue particles with a particle size of 2-10 mm, with a thickness of 3-5 cm, loosely spread, and according to 200 g / m³ 2 A layer of coconut fiber vegetation blanket is laid on its surface.
[0019] By employing the above technical solution, the present invention has at least the following advantages and beneficial effects:
[0020] (I) This invention reconstructs a near-natural coal gangue soil profile by constructing a three-in-one structure of a heat-insulating and water-permeable layer, a water-retaining layer, and a water-blocking layer, thereby achieving the effects of heat insulation and water permeability in the upper layer, water retention in the middle layer, and water blocking in the lower layer.
[0021] (ii) Using local materials to save costs. Local soil is scarce, and the cost of using imported soil for remediation is high. However, using local coal gangue as the main material and adding a small amount of functional materials to reconstruct the permafrost layer is a win-win situation. It can promote the restoration of the permafrost layer and realize the resource utilization of coal gangue.
[0022] (III) Reasonable structure, simple and practical. Compared with the traditional backfilling method of coal gangue slag heap soil, the three-in-one near-natural reconstructed coal gangue soil profile proposed in this invention, consisting of a heat insulation and water permeable layer, a water retention layer, and a water-blocking layer, has a more reasonable structure, richer layers, and is simple and practical to operate.
[0023] (IV) Significant Effects and Bright Application Prospects. Within the tested moisture content range, the thermal conductivity of the heat-insulating and permeable layer decreased by an average of 44.27%, and its saturated hydraulic conductivity was 2.28 times that of traditional backfilled coal gangue slag heap soil. The capillary water holding capacity of the water-retaining layer was 24.85%, 1.99 times that of the coal gangue slag heap soil. The water-blocking layer was impermeable in the test and effectively blocked water. This has practical applications for permafrost restoration in high-altitude and cold regions. Attached Figure Description
[0024] Figure 1 This is a comparative schematic diagram of the cross-section of coal gangue in a preferred embodiment of the present invention.
[0025] Figure 2 This is a diagram illustrating the water retention effect of the middle layer in a preferred embodiment of the present invention.
[0026] Figure 3 This is a diagram illustrating the growth effect of surface vegetation in a preferred embodiment of the present invention. Detailed Implementation
[0027] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.
[0028] The polyacrylamide (PAM) water-blocking agent used in the following examples is model CG-PAM2020, purchased from Beijing Century Green Technology Co., Ltd.
[0029] Sodium-based bentonite was purchased from Henan Borun Foundry Materials Co., Ltd.
[0030] KSAP (Kita potassium salt water-retaining agent) was purchased from Beijing Century Green Technology Co., Ltd.
[0031] The superabsorbent polymer (SAP) water-retaining agent, model SDK324, was purchased from Qingdao Shouke New Materials Co., Ltd.
[0032] Example 1: Method for Reconstructing Permafrost Layer in High-Altitude Mining Areas
[0033] like Figure 1 As shown, the present invention provides a reconstructed structure of permafrost layer in a cold mining area, which consists of a water-blocking layer, a water-retaining layer, a vegetation layer and a heat-insulating and water-permeable layer from bottom to top (Table 1).
[0034] Thermal and permeable layer: Composed of large-diameter coal gangue particles (2-10mm), 3-5cm thick, loosely laid; soil pores are mainly non-capillary pores; surface covered with a layer of coconut fiber vegetation blanket (200g / m²). 2 These measures increase soil infiltration rate but reduce soil thermal conductivity.
[0035] Water-retaining layer: Composed of medium-sized coal gangue (0.5–2 mm) with added Xitao potassium salt water-retaining agent, with a thickness of 30–40 cm and a bulk density of 100–150 N / cm³. 2 The soil pores are mainly capillary pores with moderate capillary porosity, which have good water absorption and retention capacity.
[0036] Vegetation layer: Composed of compost soil with added organic fertilizer and seeds. Thickness 5-8cm.
[0037] Water-blocking layer: Composed of small-particle-size (<0.5mm) coal gangue with polyacrylamide (PAM) water-blocking agent, with a thickness of 5-8cm and a compactness of 150-200N / cm. 2 It has a strong water absorption and retention capacity, poor permeability, and forms a barrier layer to prevent water from seeping down.
[0038] Table 1. Main characteristics of different levels
[0039]
[0040] The construction process is as follows: excavate the profile, screen the coal gangue, remove large-volume stones—backfill small-diameter coal gangue and add polyacrylamide (PAM) water-blocking agent, mix well and compact—backfill medium-diameter coal gangue and add Xitao potassium salt water-retaining agent (KSAP), mix well and compact—backfill slag soil with added organic fertilizer and seeds—backfill large-diameter coal gangue—lay coconut fiber vegetation blanket.
[0041] Example 2 Indoor Test Results
[0042] Using the reconstructed structure of the frozen soil layer in the high-altitude mining area from Example 1, the saturated hydraulic conductivity of the heat-insulating and permeable layer reached 4.10 mm / min, compared to 1.80 mm / min for the traditional backfilled coal gangue profile, representing an increase of 127.78%. Within the tested moisture content range, the thermal conductivity decreased by an average of 44.27%, demonstrating excellent heat insulation capabilities. The maximum water holding capacity of the water-retaining layer reached 29.11%, compared to 20.82% for the traditional backfilled coal gangue profile, representing an increase of 39.82%. The capillary water holding capacity was 24.85%, compared to 12.49% for the traditional backfilled coal gangue profile, representing an increase of 98.96%. The field water holding capacity was 22.39%, compared to 10.13% for the traditional backfilled coal gangue profile, representing an increase of 121.03%. The saturated water conductivity of the water-blocking layer is 0 mm / min within 24 hours, indicating poor permeability and preventing water from seeping downwards.
[0043] See the water retention effect of the middle layer Figure 2 The growth effect of surface vegetation is shown in Figure 3 .
[0044] Plant varieties: Tongde short-awned crested wheatgrass, Qinghai grassland Kentucky bluegrass, Qinghai cold-field Kentucky bluegrass, Qinghai Chinese fescue, with a planting ratio of 1:1:1:1.
[0045] The formation of permafrost requires a low-temperature environment; the lower the soil temperature, the more conducive it is to freezing. This necessitates that the upper soil layer can prevent heat transfer downwards, slowing down the temperature rise across the profile and acting as insulation. Sufficient moisture is also required for permafrost formation. Therefore, the surface soil must have good permeability to ensure rapid water infiltration, the middle soil layer must have good water absorption and retention capacity to provide moisture support for permafrost formation, and the lower soil layer must have strong water-blocking capacity to form a stable freezing interface, but not completely block water to replenish groundwater.
[0046] The present invention provides a structure and method for reconstructing permafrost in high-altitude mining areas, forming a reconstructed coal gangue soil profile consisting of an upper heat-insulating and water-permeable layer, a middle water-retaining layer, and a lower water-blocking layer.
[0047] The surface insulation and permeable layer is constructed using large-diameter coal gangue particles and covered with coconut fiber vegetation blankets, forming a soil structure with numerous large pores, good air connectivity, and high saturation infiltration rate. This effectively increases the infiltration volume and rate. At the same time, the increase in large pores means an increase in the air content within the soil, and the laying of coconut fiber vegetation blankets significantly reduces the thermal conductivity of the soil, thus preventing heat from moving downwards.
[0048] The intermediate water-retaining layer is constructed using medium-sized coal gangue particles with added water-retaining agents, forming a layered structure with abundant capillary pores and good water retention capacity. This layer can effectively absorb and store water infiltrating from the surface, providing the necessary moisture for the formation of frozen soil.
[0049] The lower water-blocking layer is constructed by adding water-blocking agents to small-diameter coal gangue particles, forming a dense and compact soil structure with extremely strong water absorption and retention capacity and poor water permeability, thus forming a barrier layer to prevent water from seeping down from above.
[0050] Overall, the multi-layer profile reconstruction of the coal gangue soil, with its coarse upper layer and fine lower layer, creates an infiltration pattern with a gradually decreasing infiltration rate. This results in water retention in each layer, reducing the water redistribution rate and improving the overall water-holding capacity of the soil.
[0051] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.
Claims
1. A reconstructed structure for permafrost in high-altitude mining areas, characterized in that, From bottom to top, the layers are: water-blocking layer, water-retaining layer, vegetation layer, and heat-insulating and water-permeable layer. The water-blocking layer is composed of coal gangue with a particle size of < 0.5 mm and a water-blocking agent; the water-blocking agent is polyacrylamide or sodium bentonite. The water-retaining layer is composed of coal gangue with a particle size of 0.5~2 mm and a water-retaining agent; the water-retaining agent is potassium polyacrylate. The vegetation layer is composed of slag soil with added organic fertilizer and seeds; The heat-insulating and water-permeable layer is composed of coal gangue particles with a particle size of 2-10mm, and the surface is covered with a layer of coconut fiber vegetation blanket. The thickness of the water-blocking layer is 5-8 cm, and the compactness is 150-200 N / cm. 2 per m 3 Add 200g of water-blocking agent to the coal gangue; The thickness of the water-retaining layer is 30-40 cm, and the compactness is 100-150 N / cm. 2 per m 3 Add 200g of water-retaining agent to the coal gangue; The thickness of the heat-insulating and water-permeable layer is 3-5cm, and it is prepared at 200g / m³. 2 Lay out a coconut fiber vegetation blanket.
2. The application of the structure described in claim 1 in soil improvement and ecological restoration in high-altitude mining areas.
3. A method for reconstructing permafrost in high-altitude mining areas, characterized in that, include: (1) Excavate the profile, screen the coal gangue, and remove large-volume stones; (2) Backfill with small-diameter coal gangue and add water-blocking agent, mix well and compact; (3) Backfill with medium-diameter coal gangue and add water-retaining agent, mix well and compact; (4) Backfill with slag soil with added organic fertilizer and seeds; (5) Backfill with large-diameter coal gangue; (6) Lay coconut fiber vegetation blanket; The water-blocking agent is polyacrylamide or sodium bentonite; the water-retaining agent is potassium polyacrylate. Step (2) in every m 3 Add 200g of water-blocking agent to coal gangue with a particle size < 0.5 mm, mix well, and compact to a thickness of 5-8cm, with a compaction degree of 150-200 N / cm. 2 ; Step (3) in every m 3 Add 200g of potassium polyacrylate water-retaining agent to coal gangue with a particle size of 0.5~2 mm, mix well, and compact to a thickness of 30~40cm with a compaction degree of 100~150 N / cm. 2 ; Step (5) Backfill with coal gangue particles with a particle size of 2-10mm, with a thickness of 3-5cm, loosely spread, and follow the 200g / m³ standard. 2 A layer of coconut fiber vegetation blanket is laid on its surface.