Gangue filling and reclamation method

Abstract

The present disclosure relates to a method for filling and reclaiming gangue. A composite structure of gangue - concrete mortar - loess is used to landfill the gully area, which can prevent the oxidation and heat generation of gangue and the precipitation of harmful elements, and eliminate the negative impact brought by the gully topography while solving the problem of gangue occupying land. The method includes: determining the filling thickness ratio of the loess layer to the gangue layer according to the thermal physical properties of the gangue and the loess; determining the first thickness corresponding to the loess layer and the second thickness corresponding to the gangue layer according to the filling thickness ratio; filling gangue with the first thickness at the bottom layer in the gully area and rolling it flat to form the first gangue layer 1; spraying concrete mortar on the surface of the first gangue layer 1 to form the first concrete mortar layer 2, and the concrete mortar includes gangue, cement, and medium sand; covering loess with the second thickness above the first concrete mortar layer 2 and rolling it flat to form the first loess layer 3; covering the topsoil above the first loess layer 3 and rolling it flat to form the topsoil layer 4.

Description

Technical Field

[0001] The present disclosure relates to the technical field of reclamation, and in particular, to a gangue filling reclamation method. Background Art

[0002] Gangue is a solid waste discharged during coal mining and coal washing and processing. In China, the cumulative stockpile of coal gangue has exceeded 5 billion tons, and it is still increasing at a rate of 300 million to 350 million tons per year. The large-scale stockpile of coal gangue not only wastes land resources, but also may cause spontaneous combustion, rain erosion, sludging, etc., which pose serious hazards to the environment. Therefore, using gangue to fill and reclaim farmland and reclaiming forest on gangue mountains have become important tasks for the utilization of coal gangue. Summary of the Invention

[0003] The purpose of the present disclosure is to provide a gangue filling reclamation method to solve the problem of gangue occupying land and eliminate the negative impacts brought by the gully terrain.

[0004] To achieve the above purpose, the present disclosure provides a gangue filling reclamation method, including:

[0005] Determine the filling thickness ratio of the loess layer to the gangue layer according to the thermal physical properties of gangue and loess;

[0006] Determine the first thickness corresponding to the loess layer and the second thickness corresponding to the gangue layer according to the filling thickness ratio;

[0007] Fill the gangue with the second thickness at the bottom layer in the gully area and roll it flat to form a first gangue layer;

[0008] Spray concrete mortar on the surface of the first gangue layer to form a first concrete mortar layer, and the concrete mortar includes gangue, cement, and medium sand;

[0009] Cover the loess with the first thickness above the first concrete mortar layer and roll it flat to form a first loess layer;

[0010] Cover the topsoil above the first loess layer and roll it flat to form a topsoil layer.

[0011] Optionally, it further includes:

[0012] Reserve multi-purpose holes during filling for grouting through the multi-purpose holes;

[0013] The multi-purpose holes are arranged at a preset spacing, and the preset spacing is determined according to the diffusion radius of the grouting liquid.

[0014] Optionally, the diffusion radius of the grouting liquid is determined by the following calculation formula:

[0015]

[0016] Among them, r represents the diffusion radius of the grouting fluid, p represents the porosity of the gangue in the gangue layer, K represents the permeability coefficient of the gangue layer, represents the grouting pressure, R represents the radius of the multi-purpose hole in the gangue layer, q represents the pumping volume of the grouting pump, t represents the grouting time used to reach the grouting pressure.

[0017] Optionally, covering the upper surface soil above the first loess layer and rolling it flat to form a surface soil layer includes:

[0018] Covering gangue with a thickness of the second thickness above the first loess layer and rolling it flat to form a second gangue layer;

[0019] Spraying concrete mortar on the surface of the second gangue layer to form a second concrete mortar layer;

[0020] Covering loess with a thickness of the first thickness above the second concrete mortar layer and rolling it flat to form a second loess layer;

[0021] Covering the upper surface soil above the second loess layer and rolling it flat to form the surface soil layer.

[0022] Optionally, determining the filling thickness ratio of the loess layer and the gangue layer according to the thermal physical properties of the gangue and the loess includes:

[0023] According to the heat transfer process of the gangue under different filling thickness ratios of the gangue and the loess, use numerical simulation software to determine whether heat transfer will occur towards the center of the gangue layer under different filling thickness ratios to determine the filling thickness ratio.

[0024] Optionally, determining the second thickness corresponding to the gangue layer according to the filling thickness ratio includes:

[0025] Determine the initial thickness of the gangue layer according to the filling thickness ratio and the stacking volume of the gangue;

[0026] Determine the first porosity before the gangue is compacted and the second porosity after the gangue is compacted;

[0027] Calculate the height difference before and after the gangue is compacted based on the first porosity and the second porosity;

[0028] Determine the second thickness corresponding to the gangue layer based on the initial thickness and the height difference.

[0029] Optionally, the is determined by the following calculation formula:

[0030]

[0031] wherein, represents the height difference, represents the first porosity, represents the second porosity, represents the initial thickness of the gangue layer.

[0032] Optionally, before filling the bottom layer in the gully area with gangue of the second thickness and compacting it flat, it further includes:

[0033] Spraying shotcrete mortar on the inner surface of the gully area.

[0034] Optionally, before filling the bottom layer in the gully area with gangue of the second thickness and compacting it flat, it further includes:

[0035] Determine the target design elevation, the target total excavation volume, and the target total filling volume according to the filling thickness ratio and the topographic characteristics of the gully area.

[0036] Optionally, the determining the target design elevation, the target total excavation volume, and the target total filling volume according to the filling thickness ratio and the topographic characteristics of the gully area includes:

[0037] Measure the ground elevation scatter data of the gully area;

[0038] Edit the topographic map of the gully area based on the ground elevation scatter data and extract the feature lines;

[0039] Establish a digital elevation model based on the topographic map and the feature lines;

[0040] Based on the digital elevation model, determine the initial design elevation under the condition of cut-fill balance;

[0041] Adjust the initial design elevation so that the ratio of the total excavation volume to the total filling volume is equal to the ratio of the thickness of the loess layer to the total thickness of the gangue layer and the loess layer, and determine the design elevation at this time as the target design elevation, determine the total excavation volume at this time as the target total excavation volume, and determine the total filling volume at this time as the target total filling volume.

[0042] Through the above technical solution, using a three-layer composite structure of gangue-shotcrete mortar-loess to landfill the gully area can prevent the oxidation and heat generation of gangue and the precipitation of harmful elements, eliminate the negative impact brought by the gully topography while solving the problem of gangue occupying land, and improve the land use value of the reclamation area.

[0043] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:

[0045] Figure 1 is a landfill schematic diagram of a gangue filling and reclamation method shown according to an exemplary embodiment.

[0046] Figure 2 is a flowchart of a gangue filling and reclamation method shown according to an exemplary embodiment.

[0047] Figure 3 is a calculation flowchart of a digital elevation model grid method shown according to an exemplary embodiment.

[0048] Figure 4 is a schematic diagram of a multi-purpose hole shown according to an exemplary embodiment.

[0049] Figure 5 is a schematic diagram of a multi-purpose hole shown according to another exemplary embodiment.

[0050] Figure 6 is a graph of average temperature monitoring data of a filling and reclamation area shown according to an exemplary embodiment.

[0051] DESCRIPTION OF THE REFERENCE NUMERALS

[0052] DETAILED DESCRIPTION

[0053] The following is a detailed description of the specific embodiments of the present disclosure in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present disclosure, and are not used to limit the present disclosure.

[0054] A gully is a groove formed by intermittent flowing water scouring on the ground surface. It is the largest type of erosion gully, with a length that can reach several kilometers or dozens of kilometers, a depth that can reach several meters or dozens of meters, and sometimes more than one hundred meters. As the largest type of erosion gully, it is the main geomorphic feature in the western region of China. The potential safety hazards caused by it cannot be ignored. At the same time, when mining under the gully slope, due to the special terrain of the gully area, the mine pressure in the underground working face is obvious, which has a series of adverse effects on underground production.

[0055] The inventors' research found that although certain achievements have been made in the current gangue filling and reclamation technology, there are still the following deficiencies: topographic factors such as gullies are not considered, and it does not adapt to local conditions and make use of local materials, resulting in a large consumption of manpower and material resources; the problem that harmful elements are released from gangue when encountering water and pollute the surrounding soil is not considered; the problem that the gangue generates heat due to the incomplete isolation of the oxygen circulation channel is not considered.

[0056] In view of this, according to the characteristics of the coal mining area in the northwest of the Shanxi Loess Plateau, where the loess resources are rich, the vegetation is scarce, the gullies are well-developed, and the mining intensity in the area is large, the coal seams generally contain multiple intercalated gangues, and a large amount of gangue produced by mining activities accumulates. The present disclosure proposes a gangue filling and reclamation method to solve the problem of gangue occupying land and eliminate the negative impact brought by the gully topography.

[0057] Figure 1 is a filling schematic diagram of a gangue filling and reclamation shown according to an exemplary embodiment, Figure 2 is a flowchart of a gangue filling and reclamation method shown according to an exemplary embodiment. Referring to Figure 1 and Figure 2 , the gangue filling and reclamation method includes the following steps:

[0058] S11, determine the filling thickness ratio of the loess layer and the gangue layer according to the thermal physical properties of the gangue and the loess.

[0059] S12, determine the first thickness corresponding to the loess layer and the second thickness corresponding to the gangue layer according to the filling thickness ratio.

[0060] S13, fill the gangue with a second thickness at the bottom layer in the gully area and roll it flat to form the first gangue layer 1.

[0061] S14, spray the concrete mortar on the surface of the first gangue layer 1 to form the first concrete mortar layer 2. The concrete mortar includes gangue, cement, and medium sand.

[0062] S15, cover the loess with a first thickness above the first concrete mortar layer 2 and roll it flat to form the first loess layer 3.

[0063] S16, cover the topsoil above the first loess layer 3 and roll it flat to form the topsoil layer 4.

[0064] First of all, it should be understood that the gangue buried at the bottom layer of the gully can be the gangue that meets the landfill requirements after being tested for heavy metal elements. First, measure the pH value of the gangue, then compare and analyze the screening value of the agricultural land soil pollution risk at this pH value, and then determine whether the content of its heavy metal elements is lower than the risk screening value according to the food safety quality standard of the crops to determine whether it meets the safety quality standard.

[0065] Exemplarily, if the pH value of the gangue is measured to be 7.56, by comparing and analyzing the screening values of agricultural land soil pollution risks at this pH value, according to the food safety quality standards of crops, the contents of its heavy metal elements measured are shown in Table 1, all of which are lower than the risk screening values and meet the safety quality standards. Therefore, this gangue can be used to fill the bottom layer in the gully area and be rolled and leveled to form the first gangue layer 1.

[0066] Table 1

[0067]

[0068] Since the chemical components in the gangue will undergo a slow oxidation reaction when in contact with oxygen, heat will be generated and continuously accumulated during the oxidation process. When the heat accumulates to a certain temperature, it will cause the coal and combustibles in the gangue to burn, resulting in the spontaneous combustion of the gangue.

[0069] It should be understood that the function of the concrete mortar layer is to seal the gangue layer, so that water is stored in the loess layer and cannot enter the gangue layer. And soil has the characteristic of not allowing air to pass through after encountering water, and the loess layer can effectively isolate oxygen to prevent the gangue from heating and self-igniting. Thus, while preventing the harmful elements in the gangue layer from precipitating, it can also prevent the gangue from oxidizing and generating heat, which affects the growth of plants in the reclamation area. Among them, the average thickness of the concrete mortar layer can be 75 mm. Of course, the thickness of the concrete mortar layer can also be adjusted according to the actual situation, and the embodiments of the present disclosure do not limit this.

[0070] It should also be understood that covering the surface soil on the landfill plot can adjust the soil quality, provide the nutrients necessary for plant growth in the soil, and provide good living conditions for plant cultivation. The thickness of the topsoil layer 4 can be 70 cm. Of course, the thickness of the topsoil layer 4 can also be adjusted according to the actual situation, and the embodiments of the present disclosure do not limit this.

[0071] In addition, a loader can be used to lay the soil and gangue in layers, and a bulldozer can be used to level and compact the covering layer. The embodiments of the present disclosure do not limit this.

[0072] Through the above technical solution, using a three-layer composite structure of gangue-concrete mortar-loess to fill the gully area can prevent the gangue from oxidizing and generating heat and the precipitation of harmful elements, eliminate the negative impact brought by the gully terrain while solving the problem of gangue occupying land, and improve the land use value of the reclamation area.

[0073] Since the gully area was originally composed of relatively loose soil layers and was formed by intermittent water erosion, the surface soil stability in the gully area is relatively poor. Therefore, in a possible implementation manner of the present disclosure, before filling the bottom layer of the gully area with gangue of the second thickness and rolling and leveling it, concrete mortar can also be sprayed on the inner surface of the gully area.

[0074] Exemplarily, the concrete mortar can be prepared according to the weight ratio of 780 - 790 parts of gangue, 490 - 510 parts of cement, 880 - 890 parts of medium sand, and 160 - 170 parts of water. The concrete mortar can also be prepared according to the weight ratio and other materials, which is not limited in the embodiments of the present disclosure. Among them, the gangue used has a low degree of weathering and high hardness, meeting the hardness standard for making sand and gravel aggregates. The gangue can be first crushed into small pieces of gangue by a jaw crusher, and then the small pieces of gangue can be crushed into gangue particles with a particle size of 5 - 25 mm by a counterattack crusher, and then the gangue particles can be used to prepare the concrete mortar. The embodiments of the present disclosure do not limit the method of crushing the gangue and the particle size of the gangue particles. When spraying the concrete mortar, a GYP - 90 hydraulic shotcreting machine can be used to spray the concrete mortar on the bank and bottom of the gully area to be reclaimed, with a thickness of 50 mm - 100 mm, and curing is carried out 8 hours after the shotcreting construction is completed, and the curing time is 7 days. The embodiments of the present disclosure do not limit the method of spraying the concrete mortar, the thickness of the concrete mortar layer, and the curing method of the concrete mortar layer, and can be adaptively adjusted according to the actual situation in the application.

[0075] Through the above method, the concrete mortar sprayed on the inner surface of the gully area can reinforce the inside of the gully, reduce the lateral deformation of the rock mass, and thus increase the bearing capacity of the soil in the reclaimed gully area, while preventing environmental pollution caused by the leaching effect of the water in the gully soil layer on the gangue.

[0076] In a possible way, before filling the bottom layer in the gully area with gangue having a second thickness and rolling it flat, the target design elevation, the target total excavation volume, and the target total filling volume can also be determined according to the filling thickness ratio and the topographic characteristics of the gully area.

[0077] It should be understood that the calculation of the target design elevation, the target total excavation volume, and the target total filling volume is an important step in the engineering construction. During the engineering design stage, the design elevation, the target total excavation volume, and the target total filling volume must be budgeted, which is directly related to the cost estimate and the optimization of the engineering plan. The embodiments of the present disclosure do not limit the method of calculating the target design elevation, the target total excavation volume, and the target total filling volume.

[0078] Among possible methods, according to the filling thickness ratio and the topographic features of the gully area, the target design elevation, the target total excavation volume, and the target total filling volume can be determined. First, the ground elevation scatter data of the gully area can be measured, and then based on the ground elevation scatter data, the topographic map of the gully area can be edited and the feature lines can be extracted. Then, based on the topographic map and the feature lines, a digital elevation model can be established. Next, based on the digital elevation model, the initial design elevation in the case of cut-fill balance can be determined. Finally, the initial design elevation can be adjusted so that the ratio of the total excavation volume to the total filling volume is equal to the ratio of the thickness of the loess layer to the total thickness of the gangue layer and the loess layer, and the design elevation at this time can be determined as the target design elevation, the total excavation volume at this time can be determined as the target total excavation volume, and the total filling volume at this time can be determined as the target total filling volume.

[0079] For example, the process of calculating the target design elevation and the target total excavation and filling volumes through the digital elevation model is as Figure 3 shown. Referring to Figure 3 , first, based on the measured ground elevation scatter data, the topographic map of the gully area is edited and the feature lines are extracted. Then, based on the topographic map and the feature lines, a digital elevation model is established. Next, based on the digital elevation model, the initial design elevation in the case of cut-fill balance is determined. Then, the initial design elevation is adjusted, and the total excavation volume and the total filling volume are calculated based on the adjusted design elevation. It is judged whether the ratio of the total excavation volume to the total filling volume is equal to the ratio of the thickness of the loess layer to the total thickness of the gangue layer and the loess layer. When the ratio of the total excavation volume to the total filling volume is equal to the ratio of the thickness of the loess layer to the total thickness of the gangue layer and the loess layer, the design elevation and the total excavation and filling volumes at this time are determined as the target design elevation and the target total excavation and filling volumes.

[0080] For example, the ground elevation scatter data of the gully area can include the terrain point spacing, the maximum east-west distance, the maximum north-south distance, the minimum elevation, and the maximum elevation, etc. Then, earthwork calculation software such as EPS and CASS can be used to extract various topographic and geomorphic elements that affect the calculation accuracy, and a simple topographic map can be edited and generated. Feature lines such as the slope top line, slope bottom line, bank top line, bank bottom line, foot of the mountain line, ridge line, valley line, and the boundary line of the terrain with uniform elevation change or flat terrain can be extracted. Then, the simple topographic map and the feature lines are imported into the earthwork calculation software to generate a regular grid digital elevation model (DEM model). Among them, the grid size can be set to 1 meter. It should be noted that any side in the constructed DEM model cannot intersect with the feature line.

[0081] For example, the initial design elevation in the case of cut-fill balance can be calculated by the following calculation formula:

[0082]

[0083] Among them, represents the initial design elevation in the case of cut-fill balance, Represents the elevation value of the corner point, Represents the elevation value of the edge point, Represents the elevation value of the inflection point, Represents the elevation value of the midpoint.

[0084] Exemplarily, the elevation difference between each grid point and the initial design elevation can be calculated by the following calculation formula:

[0085]

[0086] where, represents the elevation value of the grid point with the abscissa of i and the ordinate of j , represents the elevation difference between the grid point with the abscissa of i and the ordinate of j and the initial design elevation.

[0087] Exemplarily, the earthwork volume of each grid point can be calculated by the following calculation formula:

[0088]

[0089]

[0090]

[0091]

[0092] where, l represents the grid point spacing, represents the earthwork volume of the corner point with the abscissa of i and the ordinate of j , represents the earthwork volume of the edge point with the abscissa of i and the ordinate of j , represents the earthwork volume of the inflection point with the abscissa of i and the ordinate of j , represents the earthwork volume of the midpoint with the abscissa of i and the ordinate of j .

[0093] Exemplarily, the total excavation volume and total filling volume in the case of excavation and filling balance can be calculated by the following calculation formula:

[0094]

[0095] where, represents the abscissa of i and the ordinate of jThe earthwork volume of the grid points, represents the total excavation volume under the condition of excavation and filling balance, represents the total filling volume under the condition of excavation and filling balance.

[0096] Among possible ways, according to the thermal physical properties of gangue and loess, the filling thickness ratio of the loess layer and the gangue layer can be determined. It can be based on the heat transfer process of gangue under different filling thickness ratios of gangue and loess. Through numerical simulation software, it is determined whether heat transfer will occur towards the center of the gangue layer under different filling thickness ratios, so as to determine the filling thickness ratio.

[0097] It should be understood that since gangue has good heat storage conditions, when the heat in the gangue layer cannot be released to the outside in time, the temperature accumulation will cause the temperature in the gangue layer to continue to rise, and the temperature feedback to the ground surface is also relatively high, which is not conducive to the survival and growth of plants. Therefore, the embodiments of the present disclosure propose to determine whether the temperature in the gangue layer will continue to rise and whether the high-temperature area will spread to the central area based on the different thermal physical properties of gangue and loess and according to the heat transfer process of loess and gangue under different thickness ratios, so as to determine the filling thickness ratio of the loess layer and the gangue layer. Among them, the thermal physical properties of loess and gangue are shown in Table 2.

[0098] Table 2

[0099]

[0100] Exemplarily, the Abaqus numerical simulation software can be used to establish a frustum of a pyramid model, add a heat source to the outer surface of the model, the internal material of the frustum of a pyramid model is loess and gangue with different thickness ratios. On the premise of ensuring the simulation accuracy and precision, only consider the problem of heat transfer of gangue, divide the frustum of a pyramid model into 11,000 heat conduction units, then set the initial temperature fields of loess, gangue and the external environment to 25 °C, and apply a spontaneous combustion temperature field of 372 °C on both sides of the model. Under different filling thickness ratios of gangue and loess, combined with the thermal physical properties of loess and gangue shown in Table 1, the temperature simulation results when the temperature transfer inside the model reaches a steady state are obtained.

[0101] For example, different thickness ratios of loess to gangue can be set as 1:4, 1:6, 1:8, 1:10, and 1:12. When the ratio of loess to gangue is 1:8, 1:10, or 1:12, the high-temperature area inside the model diffuses towards the central area, and the internal temperature is generally high. When the ratio of loess to gangue is 1:4 or 1:6, the high-temperature area inside the model does not diffuse towards the central area and shows a differential distribution. That is to say, when it is determined that the thickness ratio of loess to gangue is greater than or equal to 1:6, the high-temperature area inside the model will not diffuse towards the central area. Therefore, the thickness ratio of loess to gangue can be determined as 1:6. Of course, the thickness ratio of loess to gangue can also be determined as 1:5 or 1:4, and can be specifically adjusted according to the actual stacking amount of gangue and the economic effect. The embodiments of the present disclosure do not limit this.

[0102] In a possible way, according to the filling thickness ratio, the corresponding second thickness of the gangue layer can be determined. The initial thickness of the gangue layer can be determined based on the filling thickness ratio and the stacking amount of gangue. Then, the first porosity before compaction of the gangue and the second porosity after compaction are determined. Then, based on the first porosity and the second porosity, the height difference before and after compaction of the gangue is calculated. Finally, based on the initial thickness and the height difference, the corresponding second thickness of the gangue layer is determined.

[0103] It should be understood that due to the existence of pore space volume between gangue, after filling with gangue and rolling it flat, there will be a height difference in the gangue layer. The height difference before and after compaction of the gangue can be calculated based on the porosity before and after compaction of the gangue, and then the corresponding second thickness of the gangue layer can be determined based on the initial height and the height difference.

[0104] Exemplarily, the corresponding second thickness of the gangue layer can be calculated by the following calculation formula:

[0105]

[0106] Among them, represents the corresponding second thickness of the gangue layer, represents the initial thickness of the gangue layer, represents the height difference before and after compaction of the gangue.

[0107] In a possible way, the height difference before and after compaction of the gangue is determined by the following calculation formula:

[0108]

[0109] Among them, represents the height difference, represents the first porosity, represents the second porosity, represents the initial thickness of the gangue layer.

[0110] Exemplarily, if it is determined that the thickness ratio of loess to gangue is 1:6, the thicknesses of the loess layer and the gangue layer can be determined to be 50 cm and 300 cm respectively according to the actual stacking amount of the gangue and the economic effect, that is, the initial thickness of the gangue layer is 300 cm. Then, through the above calculation formula, it is calculated that is 0.3658 h , then the second thickness corresponding to the gangue layer is: = 300 + 0.3658×300 = 409.74 cm. Of course, the first thickness corresponding to the loess layer can also be determined according to the height difference of the loess before and after compaction and the initial thickness of the loess layer determined according to the thickness ratio of the loess to the gangue. The embodiments of the present disclosure do not limit this

[0111] In a possible manner, a multi-purpose hole 5 can also be reserved during filling so as to perform grouting through the multi-purpose hole 5. The multi-purpose hole 5 can be set at a preset spacing, and the preset spacing can be determined according to the diffusion radius of the grouting liquid

[0112] It should be understood that since the inside of the gully area is reclaimed by filling with gangue, loess and concrete mortar, the soil structure inside is more complex compared with the non-reclaimed area. And due to the structure and chemical properties of the gangue, the stability of the reclaimed area filled with gangue is lower compared with the non-reclaimed area. Therefore, a multi-purpose hole can be reserved during filling. As Figure 4 shown, a temperature sensor can be set in the multi-purpose hole 5 in the gangue layer. When the temperature inside the gully is monitored to be abnormal, the multi-purpose hole 5 can be used as a grouting hole, and the gangue layer can be temperature-controlled grouted through the multi-purpose hole 5 to adjust the temperature inside the gangue layer. It is also possible to perform reinforcement grouting on the gangue layer through the multi-purpose hole 5 to improve the bearing capacity of the gangue layer. It is also possible to perform water-blocking and reinforcement grouting on the concrete mortar layer to further prevent water in the gully soil layer from flowing into the gangue layer. The embodiments of the present disclosure do not limit the specific uses of the multi-purpose hole 5 and the grouting materials used during grouting

[0113] In a possible manner, the diffusion radius of the grouting liquid is determined by the following calculation formula:

[0114]

[0115] wherein r represents the diffusion radius of the grouting liquid p represents the porosity of the gangue in the gangue layer K represents the permeability coefficient of the gangue layer represents the grouting pressure R represents the radius of the multi-purpose hole 5 in the gangue layer q represents the pump volume of the grouting pump t represents the grouting time used to reach the grouting pressure

[0116] Exemplarily, Figure 3 FIG. 5 is a schematic structural diagram of a multi-purpose hole according to another exemplary embodiment. As Figure 3 shown, the preset grouting section length a can be determined according to the second thickness corresponding to the gangue layer. If the second thickness corresponding to the gangue layer is 300 cm, then the preset grouting section length a can be determined to be 300 cm, and the multi-purpose hole 5 in the gangue layer is arranged in the middle of the gangue layer so that the grouting liquid can spread more fully into the gangue layer. If the thickness of the gangue layer is relatively large, it can also be as Figure 5 shown, multiple multi-purpose holes 5 are arranged in the gangue layer, and the embodiments of the present disclosure do not limit this. If the slurry diffusion radius r is calculated to be 318 cm through the above calculation formula, then the preset spacing of the multi-purpose hole 5 can be determined to be 600 cm (the preset spacing can be less than or equal to 2 r ), or the preset spacing of the multi-purpose hole 5 can be set to 500 cm, so that the grouting can also spread into the gangue layer faster, and the embodiments of the present disclosure do not limit this either.

[0117] In a possible way, overlying soil is covered on the first loess layer 3 and rolled flat to form a topsoil layer 4. It can be that gangue with a thickness of the second thickness is covered on the first loess layer 3 and rolled flat to form a second gangue layer 6, then sprayed with concrete mortar on the surface of the second gangue layer 6 to form a second concrete mortar layer 7, then covered with loess with a thickness of the first thickness on the second concrete mortar layer 7 and rolled flat to form a second loess layer 8, and finally overlying soil is covered on the second loess layer 8 and rolled flat to form a topsoil layer 4.

[0118] It should be understood that as Figure 4 shown, the gangue layer, the concrete mortar layer and the loess layer can be determined as a composite layer, and then according to the depth of the gully and the topographic features, multiple composite layers are used to fill the gully area, and finally overlying soil is covered on the topmost loess layer and rolled flat to form a topsoil layer 4. The embodiments of the present disclosure do not limit the number of composite layers, and can be adjusted according to the topographic features of the specific gully to be filled.

[0119] Through the above technical solution, the gully area is alternately filled with a three-layer composite structure of gangue-concrete mortar-loess, which can prevent the oxidation and heat generation of gangue and the precipitation of harmful elements, eliminate the negative impact brought by the gully topography while solving the problem of gangue occupying land, and improve the land use value of the reclamation area. At the same time, multi-purpose holes are reserved during filling, and the gangue layer is temperature-controlled grouted through the multi-purpose holes to adjust the internal temperature of the gangue layer in real time, which is beneficial to the survival of plants in the reclamation area.

[0120] Figure 6It is a graph showing the average temperature monitoring data of a filled reclamation area according to an exemplary embodiment. The highest monitored temperature of the gangue layer is 22.4 °C, and the lowest monitored temperature is 20.5 °C. The highest monitored temperature of the topsoil layer is 20.7 °C, and the lowest monitored temperature is 20.0 °C. Therefore, the above-mentioned gangue filling and reclamation method can effectively inhibit the low-temperature oxidation of gangue and provide a suitable temperature for the growth of vegetation.

[0121] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0122] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0123] Furthermore, any combination can be made between various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A method for filling and reclaiming gangue, characterized in that, it includes: Determine the filling thickness ratio of the loess layer to the gangue layer according to the thermal physical properties of the gangue and the loess; Determine the first thickness corresponding to the loess layer and the second thickness corresponding to the gangue layer according to the filling thickness ratio; Fill the gangue with the second thickness at the bottom layer in the gully area and roll it flat to form the first gangue layer; Spray concrete mortar on the surface of the first gangue layer to form the first concrete mortar layer, and the concrete mortar includes gangue, cement, and medium sand; Cover the first concrete mortar layer with loess with a thickness of the first thickness and roll it flat to form the first loess layer; Cover the topsoil on the first loess layer and roll it flat to form the topsoil layer; The determination of the second thickness corresponding to the gangue layer according to the filling thickness ratio includes: Determine the initial thickness of the gangue layer according to the filling thickness ratio and the stacking amount of the gangue; Determine the first porosity before the gangue is compacted and the second porosity after the gangue is compacted; Calculate the height difference before and after the gangue is compacted according to the first porosity and the second porosity; Determine the second thickness corresponding to the gangue layer according to the initial thickness and the height difference; The height difference is determined by the following calculation formula: Among them, represents the height difference, represents the first porosity, represents the second porosity, represents the initial thickness of the gangue layer; Before filling the gangue with the second thickness at the bottom layer in the gully area and rolling it flat, it further includes: Determine the target design elevation, the target total excavation volume, and the target total filling volume according to the filling thickness ratio and the topographic characteristics of the gully area; The determination of the target design elevation, the target total excavation volume, and the target total filling volume according to the filling thickness ratio and the topographic characteristics of the gully area includes: Measure the ground elevation scatter data of the gully area; Edit the topographic map of the gully area according to the ground elevation scatter data and extract the characteristic lines; Establish a digital elevation model according to the topographic map and the characteristic lines; Determine the initial design elevation under the condition of cut-fill balance based on the digital elevation model; Adjust the initial design elevation so that the ratio of the total excavation volume to the total filling volume is equal to the ratio of the thickness of the loess layer to the total thickness of the gangue layer and the loess layer, and determine the design elevation at this time as the target design elevation, determine the total excavation volume at this time as the target total excavation volume, and determine the total filling volume at this time as the target total filling volume; Calculate the initial design elevation under the condition of cut-fill balance through the following calculation formula: Among them, represents the initial design elevation under the condition of excavation and filling balance, represents the elevation value of the corner point, represents the elevation value of the edge point, represents the elevation value of the inflection point, represents the elevation value of the midpoint; Calculate the elevation difference between each grid point and the initial design elevation through the following calculation formula: Among them, represents the elevation value of the grid point with the abscissa being i and the ordinate being j ; represents the elevation difference between the grid point with the abscissa being i and the ordinate being j and the initial designed elevation. Calculate the earthwork volume of each grid point through the following calculation formula: Among them, l represents the grid point spacing, represents the earthwork volume of the corner point with the abscissa of i and the ordinate of j ; represents the earthwork volume of the side point with the abscissa of i and the ordinate of j ; represents the earthwork volume of the inflection point with the abscissa of i and the ordinate of j ; represents the earthwork volume of the midpoint with the abscissa of i and the ordinate of j ; Calculate the total excavation volume and total filling volume under the condition of cut-fill balance through the following calculation formula: Among them, represents the volume of earthwork of the grid point with the abscissa of i and the ordinate of j . represents the total excavation volume under the condition of cut-fill balance, represents the total filling volume under the condition of cut-fill balance.

2. The method according to claim 1, characterized in that, it further includes: Reserve multi-purpose holes during filling to facilitate grouting through the multi-purpose holes; The multi-purpose holes are arranged at a preset spacing, and the preset spacing is determined according to the diffusion radius of the grouting liquid.

3. The method according to claim 2, characterized in that, The diffusion radius of the grouting liquid is determined by the following calculation formula: Among them, r represents the diffusion radius of the grouting liquid, p represents the porosity of the gangue in the gangue layer, K represents the permeability coefficient of the gangue layer, represents the grouting pressure, R represents the radius of the multi-purpose holes in the gangue layer, q represents the pumping volume of the grouting pump, t represents the grouting time taken to reach the grouting pressure.

4. The method according to claim 1, wherein, covering the upper surface soil above the first loess layer and rolling it flat to form a surface soil layer, includes: covering gangue with a thickness of the second thickness above the first loess layer and rolling it flat to form a second gangue layer; spraying concrete mortar on the surface of the second gangue layer to form a second concrete mortar layer; covering loess with a thickness of the first thickness above the second concrete mortar layer and rolling it flat to form a second loess layer; covering the upper surface soil above the second loess layer and rolling it flat to form the surface soil layer.

5. The method according to claim 1, wherein, determining the filling thickness ratio of the loess layer and the gangue layer according to the thermal physical properties of the gangue and the loess, includes: according to the heat transfer process of the gangue under different filling thickness ratios of the gangue and the loess, determining whether heat transfer occurs towards the center of the gangue layer at different filling thickness ratios through numerical simulation software to determine the filling thickness ratio.

6. The method according to claim 1, wherein, before filling gangue with a thickness of the second thickness at the bottom layer in the gully area and rolling it flat, further includes: spraying concrete mortar on the inner surface of the gully area.

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