A method for activating dead soil layer in mine dump

Abstract

The present invention records a method for activating the dead soil layer of a mine dump, comprising the following steps: S1, analyzing the soil layer parameters of the mine dump to determine the buried depth of the dead soil layer to be activated; S2, dividing the working area into grids; S3, drilling bottle-shaped soil holes at the grids; S4, setting a grid micro-topography around the soil holes in the grids; S5, laying biochar materials at the grid micro-topography, and filling the soil holes with humus materials. This method can form a concave catchment area by dividing the mine dump into grids, which can make full use of rainwater; and the grids can avoid large-scale tillage and soil layer reconstruction, and reduce the disturbance of the surface soil and plants in the mine dump. Bottle-shaped soil holes are set in the grids, which can further gather rainwater, and the rainwater moves to the surrounding areas in the soil holes to replenish water for the plant roots; the soil holes gradually collapse under the action of soil collapse, which plays a role in local soil loosening.

Description

Technical Field

[0001] The invention relates to the technical field of mine ecological restoration, and in particular to a method for activating a dead soil layer in a mine dump. Background Art

[0002] Due to objective reasons such as mechanical compaction and poor soil structure, a dead soil layer is usually formed below 5-10 cm of the surface soil in the mine spoil dump.

[0003] The dead soil layer easily leads to difficulty in water infiltration, low soil fertility, and hindered root growth of vegetation, which seriously restricts the succession of plant communities after ecological restoration of mine dumps, makes it difficult to resist drought disturbances, and easily causes secondary degradation of the ecosystem. Therefore, as the focus of ecological and environmental governance in mining areas, the ecological restoration of mine dumps urgently needs to solve the problem of revitalizing the dead soil layer in mine dumps.

[0004] The existing soil remediation technology for spoil dumps mainly focuses on constructing a reasonable soil layer structure during the spoil dumping process, such as the sponge spoil dump construction technology and the active soil layer construction technology, so as to avoid the formation of a dead soil layer. However, there is still a lack of activation technology for the dead soil layer problem in the spoil dumps that have already formed. In addition, the soil layer structure of the existing spoil dumps has already been formed, and the forest and grass vegetation on the ground has begun to recover. The economic and ecological costs of soil layer reconstruction and topsoil tillage are high.

[0005] Based on the above objective reasons, it is urgent to develop an economically feasible dead soil layer activation technology. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a method for activating the dead soil layer of a mine spoil dump.

[0007] The technical solution of the present invention is:

[0008] A method for activating a dead soil layer in a mine dump comprises the following steps:

[0009] S1, analyze soil layer parameters in the operating area of ​​the mine spoil dump that needs ecological restoration, and determine the burial depth of the dead soil layer that needs to be activated;

[0010] S2, dividing the operation area into grids;

[0011] S3, drilling soil holes at the mesh squares, with the main part of the soil holes being set in the dead soil layer;

[0012] S4, in the mesh square, the mesh square microtopography was set around the soil holes;

[0013] S5, laying biochar material on the grid-like micro-topography, and filling humus material into the soil pores.

[0014] Furthermore, in step S1, the soil layer parameters include the soil moisture content θ and bulk density ρ of the soil layer profile in the operation area; the dead soil layer has a soil moisture content θ≦6% and a bulk density ρ≧1.5g / cm 3 of soil layer.

[0015] Furthermore, the criterion for determining whether the dead soil layer needs to be activated is that the burial depth of the dead soil layer is less than the thickness of the effective soil layer.

[0016] Furthermore, in step S2, the spacing of the mesh squares is determined by the following formula:

[0017] d=2×(a1×ρ+a2×θ+a3×P×d 2 / 1000+a4)

[0018] In the formula,

[0019] d is the spacing of the mesh squares, unit: m;

[0020] θ is the soil moisture content of the dead soil layer, unit: %;

[0021] ρ is the bulk density of the dead soil layer, unit: g / cm 3 ;

[0022] P is the average annual rainfall in the mine dump, unit: mm;

[0023] a1, a2, and a3 are the fitting parameters of ρ, θ, and P, respectively;

[0024] a4 is the fitting constant term.

[0025] Furthermore, in step S3, the top diameter of the soil hole is ≥10 cm, and the volume of the soil hole in the dead soil layer is ≥10000 cm 3 .

[0026] Furthermore, in step S3, the shape of the soil hole is a large-bellied bottle-shaped with a narrow upper opening, and the main part of the soil hole is arranged in the dead soil layer.

[0027] Furthermore, the narrow end diameter of the bottle-shaped soil hole is ≧10 cm, the foot diameter is ≧15 cm, and the maximum belly diameter is ≧20 cm.

[0028] Furthermore, the micro-topography of the mesh square is arranged in a funnel shape, the soil holes are low-lying, and the edges of the mesh square are high-lying;

[0029] When the working area is cultivated land, the soil hole depth is 40-60 cm;

[0030] When the operation area is a forest, the soil hole depth is 30-40 cm;

[0031] When the working area is grassland, the soil hole depth is 20-30 cm.

[0032] Furthermore, in step S5, the biochar material includes one or more of straw, coal gangue or fly ash modified biochar materials; and the humus material includes straw and / or dead branches and leaves.

[0033] Furthermore, the application amount of the biochar material is 1-2 kg / m 2 .

[0034] The beneficial effects of the present invention are:

[0035] 1. The method described in the present invention divides the ecological restoration operation area of ​​the mine dump into grids, sets soil holes at the center of the grids, and uses the soil drilled and cleaned out of the soil holes to make grid micro-topography, forming a concave catchment area in the grids, which can make full use of rainwater and reduce the irrigation cost of the mine dump.

[0036] 2. The method described in the present invention sets the soil hole in a large-bellied bottle-shaped shape, which can further collect rainwater and reduce the evaporation loss of water in the soil dump. At the same time, rainwater moves around in the bottle-shaped soil hole to replenish water for the plant roots; and the bottle-shaped soil hole gradually collapses under the effect of soil collapse, which plays a role in local soil loosening and reduces the soil bulk density of the dead soil layer.

[0037] 3. The method described in the present invention is to fill the soil pores with humus such as straw or dead branches and leaves, and lay biochar in the mesh grid. When the soil pores collapse, the humus and biochar can be mixed with the collapsed soil, and further improve the physical and chemical properties of the soil in the mine dump, increase the organic matter and porosity;

[0038] 4. The method described in the present invention adopts a mesh grid method for construction, which can avoid large-scale tillage and soil layer reconstruction, reduce the disturbance of the surface soil and plants in the mine dump, and save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 : A schematic diagram of the cross-sectional structure of a soil hole in an exemplary embodiment of the present invention;

[0040] Figure 2 : A schematic diagram of a mesh grid structure in an exemplary embodiment of the present invention;

[0041] Figure 3 : Schematic diagram of the process of the present invention.

[0042] Explanation of symbols

[0043] 1-dead soil layer; 2-grid; 3-soil holes. DETAILED DESCRIPTION

[0044] It should be noted that certain words are used in the present invention to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. Therefore, this specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction.

[0045] The following is combined with Figure 1 and attached Figure 2 , the present invention is described in detail by way of embodiments.

[0046] The invention records a method for activating a dead soil layer in a mine spoil dump, which specifically comprises the following steps.

[0047] S1, analyzing soil layer parameters of the operating area of ​​the mine spoil dump that needs ecological restoration, and determining whether there is a dead soil layer in the operating area based on the soil layer parameters;

[0048] Determine the depth of dead soil layer in the working area;

[0049] Determine whether the dead soil layer needs to be activated.

[0050] Specifically:

[0051] S101, excavating soil profiles in the area of ​​the mine spoil dump to be restored;

[0052] S102, measuring soil layer parameters at different depths of the soil profile, the soil layer parameters including but not limited to soil moisture content θ and bulk density ρ;

[0053] S103, soil moisture content θ ≤ 6% and bulk density ρ ≥ 1.5 g / cm 3 The soil layer is determined to be a dead soil layer;

[0054] S104, determining the burial depth of the dead soil layer: the burial depth of the dead soil layer is the vertical distance from the upper surface of the dead soil layer to the ground surface, and an average value may be taken;

[0055] S105, the criterion for determining whether the dead soil layer needs to be activated is: the burial depth of the dead soil layer is less than the thickness of the effective soil layer, where the thickness of the effective soil layer refers to the soil depth that can be fully utilized by plant roots.

[0056] S2, divide the operation area to be ecologically restored into grids, which can be done by marking the surface with lines or other marking methods.

[0057] The spacing of the grid squares is determined by the following formula:

[0058] d=2×(a1×ρ+a2×θ+a3×P×d 2 / 1000+a4)

[0059] In the formula,

[0060] d is the spacing of the mesh squares, unit: m;

[0061] θ is the soil moisture content of the dead soil layer, unit: %;

[0062] ρ is the bulk density of the dead soil layer, unit: g / cm 3 ;

[0063] P is the average annual rainfall in the mine dump, unit: mm;

[0064] a1, a2, and a3 are the fitting parameters of ρ, θ, and P, respectively;

[0065] a4 is the fitting constant term.

[0066] S3, a soil hole is drilled at the center of the mesh grid, and the main part of the soil hole is set in the dead soil layer.

[0067] As a preference,

[0068] Set the top diameter of the soil hole to ≥10cm;

[0069] Set the volume of the soil hole in the dead soil layer to ≥ 10000cm 3 .

[0070] Furthermore,

[0071] In order to make the soil hole have excellent ecological restoration effect, the shape of the soil hole is set to be a large-bellied bottle-shaped with a narrow upper mouth, and the main part of the soil hole is set in the dead soil layer.

[0072] The narrow end diameter of the bottle-shaped soil hole should be ≥10cm, the foot diameter should be ≥15cm, and the maximum belly diameter should be ≥20cm.

[0073] The soil hole can be excavated by drilling with an auger.

[0074] S4, in the grid, set the grid micro-topography with the soil hole as the center.

[0075] The mesh grid micro-topography is preferably set to be funnel-shaped, that is, the soil holes are set at low terrain, and the edges of the mesh grids are set at high terrain, so as to facilitate the rainfall around the soil holes to flow into the soil holes.

[0076] In order to effectively realize resource utilization, the soil extracted when drilling soil holes is piled up together and used to build dikes at the edges of the grid to organize the grid micro-topography.

[0077] S5, laying biochar materials on the grid micro-topography and filling humus materials into the soil pores.

[0078] The biochar material is preferably modified biochar such as straw, coal gangue or fly ash, and the optimal application rate is 1-2 kg / m 2 , used to increase the porosity and permeability of soil pores;

[0079] The humus material is preferably straw or dead branches and leaves, which are cut into pieces. The length of the pieces is smaller than the depth of the soil holes. Each soil hole is evenly filled with 0.3-0.6 kg of humus material to increase the soil organic matter in the soil holes and absorb rainwater.

[0080] In step S3 of this embodiment,

[0081] The depth of the soil holes should be determined according to the effective soil layer thickness required by the land use type of the area to be restored, such as 40-60cm for cultivated land, 30-40cm for forest land, and 20-30cm for grassland.

[0082] The working principle of the present invention is briefly described below:

[0083] The grid-like micro-topography can form a concave catchment area, which enables rainwater to flow effectively into the soil pores and reduce evaporation waste;

[0084] After rainwater flows into the soil holes, it moves around in the soil holes to replenish water for plant roots;

[0085] The soil pores gradually collapse under the action of soil collapsibility, which plays a role in local soil loosening and can reduce the soil bulk density of the dead soil layer;

[0086] Biochar, straw or litter are mixed with collapsed soil to improve the physical and chemical properties of the original soil and increase soil organic matter and porosity;

[0087] After 3-5 years of rainwater accumulation, soil collapse and decomposition of organic matter, the physical and chemical properties of the soil are improved and the dead soil layer is activated.

[0088] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for activating the dead soil layer of a mine dump, characterized in that: The following steps are involved: S1, analyze soil layer parameters in the operating area of ​​the mine spoil dump that needs ecological restoration, and determine the burial depth of the dead soil layer that needs to be activated; S2, dividing the operation area into grids; S3, drilling soil holes at the mesh squares, with the main part of the soil holes being set in the dead soil layer; S4, in the mesh square, the mesh square microtopography was set around the soil holes; S5, laying biochar material on the grid micro-topography and filling humus material into the soil pores; In step S2, the spacing of the mesh squares is determined by the following formula: d=2×a1×ρ+a2×θ+a3×P×d 2 / 1000+a4 Where, d is the spacing of the mesh grid, unit: m; θ is the soil moisture content of the dead soil layer, unit: %; ρ is the bulk density of the dead soil layer, unit: g / cm 3 ; P is the average annual rainfall in the mine dump, unit: mm; a1, a2, a3 are the fitting parameters of ρ, θ, and P respectively; a4 is the fitting constant term; In step S3, the soil hole is in the shape of a large-bellied bottle with a narrow upper opening, and the main part of the soil hole is arranged in the dead soil layer; In step S5, the biochar material includes one or more of straw, coal gangue or fly ash modified biochar materials; the humus material includes straw and / or dead branches and leaves.

2. The method for activating the dead soil layer of a mine dump according to claim 1, characterized in that: In step S1, The soil layer parameters include soil moisture content θ and bulk density ρ of the soil layer profile in the operation area; The dead soil layer has a soil moisture content of θ≦6% and a bulk density of ρ≧1.5g / cm 3 of soil layer.

3. The method for activating the dead soil layer of a mine dump according to claim 1, characterized in that: The criterion for determining whether the dead soil layer needs to be activated is that the burial depth of the dead soil layer is less than the thickness of the effective soil layer.

4. The method for activating the dead soil layer of a mine dump according to claim 1, characterized in that: In step S3, the top diameter of the soil hole is ≥10 cm, and the volume of the soil hole in the dead soil layer is ≥10000 cm 3 .

5. The method for activating the dead soil layer of a mine dump according to claim 1, characterized in that: The narrow end diameter of the bottle-shaped soil hole is ≧10 cm, the foot diameter is ≧15 cm, and the maximum belly diameter is ≧20 cm.

6. The method for activating the dead soil layer in a mine dump according to claim 1, characterized in that: The micro-topography of the mesh squares is arranged in a funnel shape, the soil holes are low-lying, and the edges of the mesh squares are high-lying; When the working area is cultivated land, the soil hole depth is 40-60 cm; When the operation area is a forest, the soil hole depth is 30-40 cm; When the working area is grassland, the soil hole depth is 20-30 cm.

7. The method for activating the dead soil layer of a mine dump according to claim 1, characterized in that: The application amount of the biochar material is 1-2 kg / m 2 ; The usage amount of the humus material is 0.3-0.6kg / each soil hole.

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