Engineering soil restoration structure, design method and mountain reconstruction method for abandoned mines

Abstract

The present invention provides a structure and design method for repairing engineering slag of abandoned mines and a mountain reconstruction method, including a mine body, a horizontal reinforcement layer laid at the bottom of the excavation surface of the mine body, a plurality of downward inclined reinforcement layers laid and fixed to the mine body from the horizontal reinforcement layer upward, engineering slag sandwiched between the bottom horizontal reinforcement layer and the adjacent downward inclined reinforcement layer, and engineering slag sandwiched between the adjacent downward inclined reinforcement layers; the downward inclined reinforcement layer is connected to the mine body through anchor rods, and is interlayered with the engineering slag to form a mountain body, and a plurality of groups of downward inclined reinforcement layers and engineering slag are filled from the bottom side of the excavation surface of the mine body, and gradually stacked upward to form a reconstructed mountain body; the surface of the reconstructed mountain body is covered with an ecological covering layer, and the outer end of the reconstructed mountain body is connected to the ground through a gravity retaining wall. The present invention treats the engineering slag by piling it up, and paves a composite functional reinforcement layer that can remove pollutants and has a drainage effect therein, so as to eliminate the pollution problem and ensure the stability of the engineering slag pile.

Description

Technical Field

[0001] The present invention belongs to the technical field of construction engineering, and relates to a reconstruction of a mined mountain body, in particular to an engineering soil repair structure and design method for an abandoned mine and a mountain body reconstruction method. Background Art

[0002] In recent years, with the gradual acceleration of the industrialization process, the demand for mineral resources has also increased rapidly, resulting in an increasing development intensity and scale of mines. For a long time, the high-intensity and large-scale development of mineral resources has, while ensuring the rapid economic development, also had many negative impacts on the ecological environment, such as vegetation degradation, water and soil pollution, soil erosion, and induced geological disasters. Unrepaired mines not only inhibit the development of economic construction to a certain extent but also affect the normal life of residents. In the short term, the natural restoration of mines cannot be completed quickly, so artificial restoration is particularly important.

[0003] The restoration of abandoned mines should respect nature, conform to nature, grasp the measure between natural restoration and artificial restoration, and select a reasonable restoration method for abandoned mines. The restoration method of abandoned mines should comprehensively consider mine restoration modes such as landform reshaping, soil reconstruction, vegetation reconstruction, and landscape reproduction. The restoration method of abandoned mines needs to consider geological disaster problems such as landslides and collapses caused by the excessive slope of the original mountain body; the restoration method of abandoned mines also needs to consider the pollution problems caused by the original minerals; at the same time, the restoration method also needs to consider the re-greening problem of abandoned mines, repair the original ecological service functions, reconstruct vegetation, and create landscapes.

[0004] Most of the existing abandoned mine restoration technologies are to carry out slope cutting and slope releasing treatments on the original slopes, or use solidification means such as solidifying agents and covering layers, or prevent the recurrence of geological disasters in abandoned mines through anti-sliding measures such as anti-sliding piles and anchor bolts; use anti-seepage or neutralizing agents to prevent the spread of pollution; a small number use steel structure buildings for the reuse of abandoned mines. These methods rarely consider reshaping the original landform of the mine; at the same time, although these methods have good treatment effects on the surface pollution, they rarely consider the deep pollution caused by the residual minerals in the original mine, which is likely to cause secondary pollution. Therefore, an abandoned mine restoration method that considers project cost, landform reshaping, pollution control, and landscape reconstruction is very important.

[0005] At the same time, although most of the existing engineering soil is treated by means of landfilling, little consideration is given to the role of large-area soil filling in landform reconstruction in the treatment of abandoned mines. Therefore, the application of engineering soil in the restoration of abandoned mines can be considered. Summary of the Invention

[0006] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose an abandoned mine repair structure and design method and a mountain reconstruction method by piling up the engineering slag and adding a composite functional reinforcement layer that can remove pollutants and has drainage function to the engineering slag to eliminate the pollution problem and ensure the stability of the engineering slag pile.

[0007] The object of the present invention can be achieved through the following technical solutions: a structure for repairing engineering slag in abandoned mines, comprising a mine body, a horizontal reinforcement layer laid at the bottom of the excavation surface of the mine body, a plurality of downward inclined reinforcement layers laid upward from the horizontal reinforcement layer and fixed to the mine body, engineering slag is sandwiched between the bottom horizontal reinforcement layer and the adjacent downward inclined reinforcement layer, and engineering slag is sandwiched between adjacent downward inclined reinforcement layers; the downward inclined reinforcement layer is connected to the mine body through anchor rods, and is stacked with the engineering slag in layers, and a plurality of groups of the downward inclined reinforcement layers and the engineering slag are filled from the bottom side of the excavation surface of the mine body, and are gradually stacked upward to form a reconstructed mountain; the surface of the reconstructed mountain is covered with an ecological covering layer, and the outer end of the reconstructed mountain is connected to the ground through a gravity retaining wall.

[0008] In the above-mentioned abandoned mine engineering slag repair structure, the gravity retaining wall includes a solidified engineering slag wall, and the horizontal reinforcement layer and the downward inclined reinforcement layer extend into the engineering slag wall.

[0009] In the above-mentioned abandoned mine engineering slag repair structure, the horizontal reinforcement layer / the downward inclined reinforcement layer includes a drainage layer located in the middle, and the upper and lower sides of the drainage layer are covered with an adsorption layer. The drainage layer is connected to the anchor rod and the anchor rod is extended outward and inserted into the mine body.

[0010] In the above-mentioned abandoned mine engineering slag restoration structure, the engineering slag includes abandoned soil and waste generated during construction.

[0011] Construction specifically includes the construction, expansion, reconstruction and demolition of various buildings, structures, pipelines, etc., as well as the decoration and renovation of residents' houses.

[0012] In the above-mentioned abandoned mine engineering slag restoration structure, the ecological covering layer includes a water-conducting layer at the bottom and a vegetation water-retaining layer at the top, coarse-grained slag is laid in the water-conducting layer, and fine-grained slag is laid in the vegetation water-retaining layer.

[0013] In the above-mentioned abandoned mine engineering slag restoration structure, plants with alternating growth periods or evergreen plants are planted on the vegetation water-holding layer, and the plants include at least one of heavy metal hyperaccumulators, salt-alkali tolerant plants and acid-tolerant plants.

[0014] In the engineering soil residue repair structure of the abandoned mine described above, the included angle range between the horizontal reinforcement layer and the downward inclined reinforcement layer is 5° to 10°.

[0015] A design method for the engineering soil residue repair structure of an abandoned mine includes the following steps:

[0016] 1). Determine the load magnitude of the engineering soil residue overlying each downward inclined reinforcement layer, simplify the accumulated total load into a load set with a quadrilateral distribution, and then equivalently divide the load set into n strip-shaped load units; Apply the load units with different numbers of strips to each downward inclined reinforcement layer respectively, and decompose the load units into vertical and parallel components with respect to the downward inclined reinforcement layer.

[0017] 2). Based on the load units with different numbers of strips, calculate the anti-sliding force required for the corresponding load-bearing reinforcement layer according to the following formula:

[0018] R i = μ i (G R1 + G R2 + G R3 … + G Ri )cosα i

[0019] where R i is the anti-sliding force of the i-th layer of reinforcement layer, μ i is the friction coefficient between the i-th layer of reinforcement layer and the soil, G Ri is the weight of the i-th layer of strip, and α i is the inclination angle of the i-th layer of reinforcement layer.

[0020] 3). Calculate the sliding force according to the anti-sliding force required for each reinforcement layer:

[0021] P i = (G R1 + G R2 + G R3 … + G Ri )sinα i

[0022]

[0023] where P i is the sliding force of the i-th layer, and K si is the sliding stability safety factor of the i-th layer, which is determined according to the safety level of the reconstructed mountain body;

[0024] 4). Based on the anti-sliding force required for the reinforcement layer, calculate the length, diameter, and spacing of the anchor rods required for each layer of downward inclined reinforcement layer according to the following formula:

[0025] D = Lb

[0026] Where L is the anchorage length of the anchor rod, K is the safety factor, N is the required anchorage force of the anchor rod, d is the diameter of the anchor rod, q s is the anchorage strength between the anchor rod and different materials, a is the number of anchor rods, A is the tie rod area of the anchor rod, f tk is the standard value of the tensile strength of the tie rod of the anchor rod, D is the spacing between the anchor rods, and b is the empirical coefficient;

[0027] 5) Based on the design scheme obtained from the above calculation results, combined with the load of the reconstructed mountain body and the geological exploration data, determine the slope of the lower inclined reinforced layer, and at the same time determine the design parameters of the lower inclined reinforced layer;

[0028] 6) Initially determine the slope ratio of the reconstructed mountain body through the requirements of the repair project site and the height of the mountain body. Set a slope platform at the layered position of the engineering muck, conduct an overall anti-sliding stability check on the reconstructed mountain body, conduct a local anti-sliding stability check on each level of the slope, and then adjust the slope ratio of each level of the slope;

[0029] 7) Establish a mathematical relationship between the stability coefficient of each level of the slope and the depth of the sliding surface, and then determine the optimal platform width:

[0030] d i =min(K fd1 ,K fd2 …K fdi …K fdn )

[0031]

[0032] Where d i is the depth of the most unfavorable sliding surface, K fdn is the stability coefficient corresponding to the nth sliding surface, W i is the optimal platform width, and α is the inclination angle of the sliding surface.

[0033] A method for reconstructing a mountain body of an engineering muck repair structure for abandoned mines, which is applied to the design method of the engineering muck repair structure for abandoned mines as described above, and includes the following steps:

[0034] 1) Lay a horizontal reinforced layer on the original rock foundation;

[0035] 2) Take samples of the engineering muck, at least measure its water content, unit weight, internal friction angle, and cohesion index. Use the same type of engineering muck as a single-layer fill, conduct layered filling for different types of engineering muck, and fill the engineering muck with a larger internal friction angle value in the lower layer and the engineering muck with a larger cohesion value in the upper layer;

[0036] 3), Interlayer fill the engineering muck and the downward inclined reinforced layer, set slope platforms at the layered positions of the engineering muck, determine the slope ratios of each level of the slope and the widths of each level of slope platforms according to the design scheme, and lay them layer by layer on the reconstructed mountain body;

[0037] 4), During the laying process of the downward inclined reinforced layer, drive the corresponding number and positions of anchor rods into the reinforced layer according to the design scheme, so that the anchor rods are fully connected to the downward inclined reinforced layer. At the same time, drive the anchor rods into the original mine body, and use the anchor rods to tightly connect the downward inclined reinforced layer to the original mine body;

[0038] 5), Use the solidified and formed engineering muck as the main body to build a gravity retaining wall, which is leaned against the slope of the reconstructed mountain body for reinforcement and stability;

[0039] 6), Lay an ecological covering layer on the surface of the reconstructed mountain body, including a water-conducting layer at the lower part and a vegetation water-holding layer at the upper part, and plant plants with alternating growth periods or evergreen throughout the year on the water-holding layer.

[0040] Compared with the prior art, the engineering muck repair structure, design method and mountain reconstruction method of this abandoned mine have the following beneficial effects:

[0041] 1. Utilize the good drainage performance and pollutant adsorption performance of the composite functional reinforced layer, and adopt the method of interlayer filling the downward inclined reinforced layer with a certain slope and the engineering muck to solve the problems of difficult drainage and consolidation of engineering muck with high water content and the pollution problems that are prone to occur in abandoned mines.

[0042] 2. Utilize the multi-functional composite effect of the downward inclined reinforced layer, horizontal reinforced layer and gravity retaining wall, and the anchor rods in the reinforced layer provide sufficient anti-sliding force through reinforcement to avoid the sliding of the piled mountain, which not only solves the problem of easy instability and landslide of the piled engineering muck with high water content, but also improves the strength and stability of the reconstructed mountain body.

[0043] 3. Due to the reduction of the shear strength of the piled mountain body caused by rainwater infiltration, the problem of easy instability of the reconstructed mountain body after rainfall is solved by setting multi-level slope platforms and gravity retaining walls. At the same time, the gravity retaining wall uses solidified engineering muck as the main body, which further improves the utilization degree of the engineering muck.

[0044] 4. In the ecological covering layer, utilize the capillary blocking effect generated by the different penetration abilities between the coarse-grained muck and the fine-grained muck and the root water-holding effect of the vegetation layer to slow down the rate of rainwater infiltrating into the piled mountain body, that is, adopt the ecological covering layer to achieve ecological revegetation and solve the problem of softening of the filled soil of the reconstructed mountain body caused by rainwater infiltration. Brief Description of the Drawings

[0045] Figure 1 It is the overall schematic diagram of the engineering muck repair structure of this abandoned mine.

[0046] Figure 2 It is a partial enlarged schematic view of the engineering muck repair structure of this abandoned mine.

[0047] Figure 3 It is a partial enlarged schematic view of the ecological covering layer in the engineering muck repair structure of this abandoned mine.

[0048] Figure 4 It is a schematic diagram of load distribution in the design method of the engineering muck repair structure of this abandoned mine.

[0049] In the figure, 1 is the original mine body; 2 is the horizontal reinforcement layer; 3 is the downward inclined reinforcement layer; 4 is the engineering muck; 5 is the ecological covering layer; 6 is the gravity retaining wall; 7 is the adsorption layer; 8 is the drainage layer; 9 is the anchor rod; 10 is the water conduction layer; 11 is the vegetation water holding layer; 12 is the load unit. Specific implementation manners

[0050] The following are specific embodiments of the present invention and in combination with the accompanying drawings, the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0051] Embodiment 1

[0052] As Figures 1 to 3 shown, the engineering muck repair structure of this abandoned mine includes the original mine body 1, the horizontal reinforcement layer 2 laid at the bottom of the excavated original mine body 1, several downward inclined reinforcement layers 3 laid upward layer by layer from the horizontal reinforcement layer 2 and fixed to the original mine body 1, the engineering muck 4 sandwiched between the bottom horizontal reinforcement layer 2 and the adjacent downward inclined reinforcement layer 3, and the engineering muck 4 filled between the adjacent downward inclined reinforcement layers 3; the downward inclined reinforcement layer 3 is connected to the original mine body 1 through the anchor rod 9 and is filled with the engineering muck 4 in an interlayer manner, and the soil is gradually piled up upward to form a reconstructed mountain body; the surface of the reconstructed mountain body is covered with the ecological covering layer 5, and the outer end of the reconstructed mountain body is connected to the ground through the gravity retaining wall 6.

[0053] The bottom surface of the original mine body 1 is extended outward through the horizontal reinforcement layer 2 to serve as a stable foundation for the reconstructed mountain body. The framework of the reconstructed mountain body is formed by several downward extending downward inclined reinforcement layers 3, thereby improving the supporting force and stability of the reconstructed mountain body. The slope surface of the reconstructed mountain body includes alternately connected platform slopes and downward inclined slopes, and the outer end of the reconstructed mountain body is connected to the top surface of the gravity retaining wall 6 through the platform slope.

[0054] The gravity retaining wall 6 includes the solidified engineering muck 4, and the horizontal reinforcement layer 2 and the downward inclined reinforcement layer 3 extend into the engineering muck. The gravity retaining wall 6 is filled with the solidified engineering muck and the reinforcement layer in an interlayer manner to form a blocking force at the foot of the slope of the reconstructed mountain body, which is used to prevent local instability of the slope and avoid landslides.

[0055] The construction waste 4 is solidified by at least one solidifying agent selected from cement, lime, phosphogypsum, steel slag, iron tailings, etc. The above-mentioned various construction wastes 4 are solidified comprehensively to enhance the strength of the gravity retaining wall 6 and to recycle other industrial wastes.

[0056] The horizontal reinforcement layer 2 / downward oblique reinforcement layer 3 includes a drainage layer 8 in the middle, and the upper and lower sides of the drainage layer 8 are covered with an adsorption layer 7. The drainage layer 8 is connected to the anchor rod 9 and the anchor rod 9 is extended outward and inserted into the mine body 1. The adsorption layer 7 filters the groundwater and adsorbs pollutants to achieve the effect of removing soil pollution. The drainage layer 8 is specifically made of plastic material, so that the water is discharged along the drainage layer 8 to reconstruct the mountain to achieve the effect of soil consolidation. The reconstructed mountain is connected to the mine body 1 through the tension of the anchor rod 9. The horizontal reinforcement layer 2 is used to control the difference in foundation settlement. The downward oblique reinforcement layer 3 forms a multifunctional composite structure and is connected with the anchor rod 9, which not only realizes the strength support of the reconstructed mountain, but also ensures the stability of the reconstructed mountain.

[0057] The engineering slag 4 includes the abandoned soil and other wastes generated during the construction, expansion, reconstruction and demolition of various buildings, structures, pipe networks, etc., as well as the decoration and renovation of houses by residents. Using the slag generated during the construction process for backfilling can reduce the cost of mountain reconstruction and realize waste utilization, which is in line with the concept of environmental protection.

[0058] The ecological covering layer 5 includes a water-conducting layer 10 at the bottom and a vegetation water-retaining layer 11 at the top. Coarse-grained slag is laid in the water-conducting layer 10, and fine-grained slag is laid in the vegetation water-retaining layer 11. Rainwater is prevented from seepage by ecological soil covering. According to the different permeabilities of unsaturated soil layers with different particle sizes, the low permeability of coarse-grained slag is utilized to prevent rainwater from infiltrating, so as to achieve the effect of water conservation in light rain and drainage in heavy rain, and solve the problem of soil softening caused by rainwater infiltration and the problem of water for plant growth. The capillary barrier effect generated at the interface between coarse-grained slag and fine-grained slag allows rainwater to be stored in the vegetation water-retaining layer 11, thereby facilitating the preservation of water bodies and facilitating vegetation growth.

[0059] Plants with alternating growth periods or evergreen plants are planted on the vegetation aquifer 11. The plants that can be selected include heavy metal hyperaccumulators, salt-alkali tolerant plants, acid-tolerant plants, and other plants that are easy to survive in polluted environments. By planting plants with alternating growth periods or evergreen plants, the effect of abandoned mines being evergreen can be achieved. The root system of the plants will enhance the water retention capacity of the aquifer and better achieve the effect of water retention. By planting heavy metal hyperaccumulators, salt-alkali tolerant plants, acid-tolerant plants, and other plants that are easy to survive in polluted environments, the ecological restoration of abandoned mines can be achieved, and pollution remediation in the soil can be further carried out.

[0060] The angle between the horizontal reinforcement layer 2 and the lower inclined reinforcement layer 3 is in the range of 5° to 10°.

[0061] Compared with the prior art, the engineering muck repair structure of this abandoned mine has the following beneficial effects:

[0062] 1. Utilize the good drainage performance and pollutant adsorption performance of the composite functional reinforced layer, and adopt the method of interlayer filling of the downward inclined reinforced layer with a certain slope and engineering muck to solve the problems that the engineering muck with high water content is not easy to drain and consolidate and the pollution problems that are prone to occur in abandoned mines.

[0063] 2. Utilize the multi-functional composite effect of the downward inclined reinforced layer, the horizontal reinforced layer and the gravity retaining wall, and provide sufficient anti-sliding force through the reinforcement of anchor bolts in the reinforced layer to avoid the sliding of the piled mountain, which not only solves the problem that the engineering muck with high water content is prone to instability and landslide after landfill, but also improves the strength and stability of the reconstructed mountain body.

[0064] 3. Since the rainwater infiltration causes the shear strength of the piled mountain body to decrease, the problem of the instability of the reconstructed mountain body after rainfall is solved by setting multi-level slope platforms and gravity retaining walls. At the same time, the gravity retaining wall uses solidified engineering muck as the main body, which further improves the utilization degree of engineering muck.

[0065] 4. In the ecological covering layer, utilize the capillary blockage effect generated by the different penetration abilities between the coarse-grained muck and the fine-grained muck and the water-holding effect of the roots of the vegetation layer to slow down the rate of rainwater infiltration into the piled mountain body, that is, adopt the ecological covering layer to achieve ecological greening and solve the problem of softening of the filled soil of the reconstructed mountain body caused by rainwater infiltration.

[0066] Embodiment 2

[0067] Based on Embodiment 1, the difference in this embodiment lies in:

[0068] A design method for the engineering muck repair structure of an abandoned mine, including the following steps:

[0069] As Figure 4 shown,

[0070] 1). Determine the load magnitude of the engineering muck 4 overlying each downward inclined reinforced layer 3, simplify the accumulated total load into a load set with a quadrilateral distribution, and then equivalently divide the load set into n strip-shaped load units 12; Act on each downward inclined reinforced layer 3 with the load units 12 corresponding to different numbers of strips, and decompose the load unit 12 into a vertical component force and a parallel component force relative to the downward inclined reinforced layer 3;

[0071] 2). Based on the load units 12 with different numbers of strips, calculate the required anti-sliding force of the corresponding bearing reinforced layer 8 according to the following formula:

[0072] R i = μ i (G R1 + G R2+G R3 … + G Ri )cosα i

[0073] where R i is the anti - sliding force of the i - th layer of reinforced layer, μ i is the static friction coefficient between the i - th layer of reinforced layer and the soil mass, G Ri is the weight of the i - th slice, α i is the inclination angle of the i - th layer of reinforced layer;

[0074] 3), According to the anti - sliding force required for each reinforced layer 8, calculate the sliding force:

[0075] P i =(G R1 +G R2 +G R3 … + G Ri )sinα i

[0076]

[0077] where P i is the sliding force of the i - th layer, K si is the sliding stability safety factor of the i - th layer; when K smin ≥1.3, the slope stability is better;

[0078] 4), Based on the anti - sliding force required for the reinforced layer 8, calculate the length, diameter and spacing of the anchor rods 9 required for each layer of the downward - inclined reinforced layer 3 according to the following formula:

[0079] D = Lb

[0080] where L is the anchorage length of the anchor rod, K is the safety factor, N is the anchorage force required for the anchor rod, d is the diameter of the anchor rod, q s is the anchorage strength between the anchor rod and different materials, a is the number of anchor rods, A is the tie - rod area of the anchor rod, f tk is the standard value of the tensile strength of the anchor - rod tie - rod, D is the spacing between the anchor rods, b is an empirical coefficient, generally taken as 0.5;

[0081] 5), Based on the design scheme obtained from the above calculation results, combined with the load of the reconstructed mountain body and the geological exploration data, determine the slope of the downward - inclined reinforced layer 3. Generally, the drainage slope is not less than 3%, and at the same time, determine the design parameters of the downward - inclined reinforced layer 3, such as the cushion thickness, reinforcement material, etc.;

[0082] 6), preliminarily determine the slope ratio of the reconstructed mountain body based on the requirements of the engineering site and the mountain height, set slope platforms at the layered positions of the engineering muck, conduct an overall anti-sliding stability check on the reconstructed mountain body, and conduct local anti-sliding stability checks on each level of the slope, and then adjust the slope ratio of each level of the slope;

[0083] Considering that the friction angle between the drainage layer 8 and the soil may be greater than the internal friction angle of the soil, the influence of the internal friction angle of the soil should be considered in the landslide stability, and the landslide stability coefficient K f The calculation adopts the calculation method recommended by the "Technical Code for the Design and Construction of Landslide Prevention and Control Projects".

[0084] 7), establish the mathematical relationship between the stability coefficient of each level of slope and the depth of the sliding surface, and then determine the optimal platform width:

[0085] d i = min(K fd1 , K fd2 …K fdi …K fdn )

[0086]

[0087] where d i is the depth of the most unfavorable sliding surface, K fdn is the stability coefficient corresponding to the nth sliding surface, W i is the optimal platform width, and α is the inclination angle of the sliding surface.

[0088] Compared with the prior art, the design method of the engineering muck repair structure of this abandoned mine has the following beneficial effects:

[0089] 1. Utilize the good drainage performance and pollutant adsorption performance of the composite functional reinforced layer, and adopt the method of interlayer filling of the downward inclined reinforced layer with a certain slope and the engineering muck to solve the problems of difficult drainage consolidation of high water content engineering muck and pollution problems that are prone to occur in abandoned mines.

[0090] 2. Utilize the multi-functional composite action of the downward inclined reinforced layer, the horizontal reinforced layer and the gravity retaining wall, and provide sufficient anti-sliding force through the anchor rod reinforcement in the reinforced layer to avoid the sliding of the piled mountain, which not only solves the problem of easy instability and landslide of high water content engineering muck after landfill, but also improves the strength and stability of the reconstructed mountain body.

[0091] 3. Due to the reduction of the shear strength of the piled mountain body caused by rainwater infiltration, the problem of easy instability of the reconstructed mountain body after rainfall is solved by setting multi-level slope platforms and gravity retaining walls. At the same time, the gravity retaining wall uses solidified engineering muck as the main body, which further improves the utilization degree of the engineering muck.

[0092] 4. In the ecological covering layer, the capillary blocking effect caused by the different penetration abilities between coarse-grained and fine-grained construction waste and the water retention effect of the root systems of the vegetation layer are utilized to slow down the rate of rainwater infiltration into the piled mountain body. That is, the ecological covering layer is adopted to achieve ecological revegetation and solve the problem of softening of the filled soil of the reconstructed mountain body caused by rainwater infiltration.

[0093] Embodiment III

[0094] Based on Embodiment I, the difference in this embodiment lies in:

[0095] A method for reconstructing a mountain body of an engineering construction waste repair structure for abandoned mines, comprising the following steps:

[0096] 1). Lay a horizontal reinforcement layer 2 on the original rock foundation; avoid uneven settlement of the foundation, and at the same time play a good drainage effect during rainfall to improve the slope stability;

[0097] 2). Take samples of the engineering construction waste 4 and measure at least its water content, unit weight, internal friction angle, and cohesion index. Use a certain thickness of the same type of engineering construction waste 4 as a single-layer fill, and conduct layered filling for different types of engineering construction waste 4. Fill the engineering construction waste 4 with a larger internal friction angle value in the lower layer and the engineering construction waste 4 with a larger cohesion value in the upper layer;

[0098] The shear strength of the deep soil layer is mainly controlled by the internal friction angle, and the shear strength of the shallow soil layer is mainly controlled by the cohesion. By filling the slag with a larger internal friction angle value in the deep layer and the slag with a larger cohesion value in the shallow layer, the landslide stability of the reconstructed mountain body is further increased.

[0099] 3). Interlayer fill the engineering construction waste 4 and the downward inclined reinforcement layer 3. Set slope platforms at the layered positions of the engineering construction waste 4. Determine the slope ratios of each level of the slope and the widths of each level of slope platforms according to the design scheme, and lay the reconstructed mountain body layer by layer;

[0100] 4). During the laying process of the downward inclined reinforcement layer 3, drive the corresponding number and positions of anchor bolts 9 into the reinforcement layer according to the design scheme, so that the anchor bolts 9 are fully connected to the downward inclined reinforcement layer 3. At the same time, drive the anchor bolts 9 into the original mine body 1, and use the anchor bolts 9 to tightly connect the downward inclined reinforcement layer 3 to the original mine body 1;

[0101] 5). Use the engineering construction waste 4 as the main body to build a gravity retaining wall 6, which is against the slope of the reconstructed mountain body for reinforcement and stability;

[0102] 6). Lay an ecological covering layer 5 on the surface of the reconstructed mountain body.

[0103] The ecological cover layer 5 is composed of a vegetation water-holding layer 11 and a water-conducting layer 10 from top to bottom. The vegetation water-holding layer 11 is filled with fine-grained slag, with a thickness ranging from 0.4 to 0.6 m, and the slope of the vegetation water-holding layer 11 is consistent with the reconstructed mountain. The water-conducting layer 10 is filled with coarse-grained slag, with a thickness ranging from 0.2 to 0.4 m, and the slope of the water-conducting layer 10 is consistent with the reconstructed mountain.

[0104] Compared with the prior art, the mountain reconstruction method of the engineering slag repair structure of the abandoned mine has the following beneficial effects:

[0105] 1. Utilize the good drainage performance and pollutant adsorption performance of the composite functional reinforced layer, and adopt the method of inter-layer filling of the downward inclined reinforced layer with a certain slope and the engineering waste soil to solve the problem of difficult drainage and consolidation of high-water content engineering waste soil and the pollution problem that is prone to occur in abandoned mines.

[0106] 2. The multifunctional composite effect of the downward inclined reinforced layer and the horizontal reinforced layer combined with the gravity retaining wall is utilized, and the reinforced layer is reinforced with anchor rods to provide sufficient anti-sliding force to prevent the mountain from sliding. This not only solves the problem of unstable landslides after high-water content engineering waste filling, but also improves the strength and stability of the rebuilt mountain.

[0107] 3. The shear strength of the mountain pile is reduced due to the infiltration of rainwater. Therefore, the problem of easy instability of the mountain after rainfall reconstruction is solved by setting up multi-level slope platforms and gravity retaining walls. At the same time, the gravity retaining wall uses solidified engineering waste as the main body, which further improves the utilization rate of engineering waste.

[0108] 4. In the ecological covering layer, the capillary barrier effect caused by the different permeability between coarse-grained slag and fine-grained slag and the water-retaining effect of the roots of the vegetation layer are utilized to slow down the rate at which rainwater infiltrates into the mountain. That is, the ecological covering layer is used to achieve ecological restoration and solve the problem of softening of the rebuilt mountain fill caused by rainwater infiltration.

[0109] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0110] Although the present invention uses more terms such as mine body 1; horizontal reinforcement layer 2; downward inclined reinforcement layer 3; engineering slag 4; ecological cover layer 5; gravity retaining wall 6; adsorption layer 7; drainage layer 8; anchor rod 9; water-conducting layer 10; vegetation water-holding layer 11; load unit 12, it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

[0111] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Claims

1. A design method for the engineering soil restoration structure of abandoned mines. The engineering soil restoration structure includes the original mine body, a horizontal reinforced layer laid at the bottom of the excavation surface of the original mine body, several downward inclined reinforced layers laid upward layer by layer from the horizontal reinforced layer and fixed to the original mine body. Engineering soil is filled between the bottom horizontal reinforced layer and the adjacent downward inclined reinforced layers, and engineering soil is filled between the adjacent downward inclined reinforced layers; the downward inclined reinforced layers are connected to the original mine body through anchor bolts and form an interlayer stacking mountain body with the engineering soil. Several groups of the downward inclined reinforced layers and the engineering soil are filled from the bottom side of the excavation surface of the original mine body and gradually stacked upward to form a reconstructed mountain body; the surface of the reconstructed mountain body is covered with an ecological covering layer, and the outer end of the reconstructed mountain body is connected to the ground through a gravity retaining wall. It is characterized in that, The design method includes the following steps: 1). Determine the load size of the engineering soil overlying each downward inclined reinforced layer, simplify the accumulated total load into a load set with a quadrilateral distribution, and then equivalently divide the load set into n strip-shaped load units; act the load units with different numbers of strips on each downward inclined reinforced layer respectively, and decompose the load units into vertical and parallel components relative to the downward inclined reinforced layer. 2). Based on the load units with different numbers of strips, calculate the anti-sliding force required for the corresponding reinforced layer to bear according to the following formula: R i = μ i (G R1 + G R2 + G R3 … + G Ri ) cos α i where R i is the anti-sliding force of the i-th reinforced layer, μ i is the friction coefficient between the i-th reinforced layer and the soil mass, G Ri is the weight of the i-th slice, α i is the inclination angle of the i-th reinforced layer; 3). Calculate the sliding force according to the anti-sliding force required for each reinforced layer. P i = (G R1 + G R2 + G R3 … + G Ri ) sin α i Among which P i is the sliding force of the i-th layer, and K si is the sliding stability safety factor of the i-th layer, which is determined according to the safety level of the reconstructed mountain body; 4). Based on the anti-sliding force required for the reinforced layer, calculate the length, diameter and spacing of the anchor bolts required for each layer of the downward inclined reinforced layer according to the following formula: where L is the anchorage length of the bolt, K is the safety factor, N is the required anchorage force of the bolt, d is the diameter of the bolt, q s is the anchorage strength between the bolt and different materials, a is the number of bolts, A is the tie-rod area of the bolt, f tk is the standard value of the tensile strength of the bolt tie-rod, D is the spacing between bolts, and b is the empirical coefficient; 5). Based on the design scheme obtained from the above calculation results, combined with the load of the reconstructed mountain body and the geological exploration data, determine the slope of the downward inclined reinforced layer, and at the same time determine the design parameters of the downward inclined reinforced layer. 6). Initially determine the slope ratio of the slope of the reconstructed mountain body according to the requirements of the restoration project site and the height of the mountain body. Set slope platforms at the positions of the engineering soil layers. Conduct an overall anti-sliding stability check on the reconstructed mountain body, and conduct a local anti-sliding stability check on each level of the slope, and then adjust the slope ratio of each level of the slope. 7). Establish a mathematical relationship between the stability coefficient of each level of the slope and the depth of the sliding surface, and then determine the optimal platform width. d i = min(K fd1 , K fd2 …K fdi …K fdn ) where d i is the depth of the most unfavorable slip surface, K fdn is the stability coefficient corresponding to the nth slip surface, W i is the optimal platform width, and α is the dip angle of the slip surface; The horizontal reinforced layer or the downward inclined reinforced layer includes a drainage layer in the middle, adsorption layers are covered on the upper and lower sides of the drainage layer, the drainage layer is connected to the anchor bolt and the anchor bolt extends outward and inserts into the original mine body.

2. The design method of the engineering muck repair structure for abandoned mines according to claim 1, characterized in that, The gravity retaining wall includes a solidified engineering soil wall, and the horizontal reinforced layer and the downward inclined reinforced layer extend into the engineering soil wall.

3. The design method of the engineering soil restoration structure for abandoned mines according to claim 1, characterized in that, The engineering soil includes the waste soil and waste generated in construction.

4. The design method of the engineering soil restoration structure for abandoned mines according to claim 1, characterized in that The ecological covering layer includes a water guiding layer at the lower part and a vegetation water holding layer at the upper part. Coarse-grained soil is laid in the water guiding layer, and fine-grained soil is laid in the vegetation water holding layer.

5. The design method of the engineering muck repair structure for abandoned mines according to claim 4, characterized in that, Plants with alternating growth periods or evergreen throughout the year are planted on the vegetation water holding layer. The plants include at least one of heavy metal hyperaccumulating plants, salt-tolerant plants and acid-tolerant plants.

6. The design method of the engineering muck repair structure for abandoned mines according to claim 1, characterized in that, The included angle range between the horizontal reinforced layer and the downward inclined reinforced layer is 5° to 10°.

7. A method for reconstructing a mountain body of an engineering soil restoration structure for abandoned mines, which is applied to the design method of the engineering soil restoration structure for abandoned mines as described in claim 1, characterized in that, Include the following steps: 1), lay a horizontal reinforced layer on the original rock foundation; 2), take samples of the engineering muck, at least measure its water content, unit weight, internal friction angle, and cohesion index. Use the same type of engineering muck as a single-layer fill, conduct stratified filling for different types of engineering muck, and fill the engineering muck with a larger internal friction angle value in the lower layer and the engineering muck with a larger cohesion value in the upper layer; 3), fill the engineering muck and the inclined reinforced layer in an interlayer manner, set slope platforms at the stratified positions of the engineering muck, determine the slope ratios of each level of the slope and the widths of each level of slope platforms according to the design scheme, and lay the reconstructed mountain layer by layer; 4), during the laying process of the inclined reinforced layer, drive the corresponding number and positions of anchor bolts into the reinforced layer according to the design scheme to make the anchor bolts fully connected to the inclined reinforced layer. At the same time, drive the anchor bolts into the original body of the mine, and use the anchor bolts to tightly connect the inclined reinforced layer to the original body of the mine; 5), use the solidified and formed engineering muck as the main body to build a gravity retaining wall, which is leaned against the slope of the reconstructed mountain for reinforcement and stability; 6), lay an ecological covering layer on the surface of the reconstructed mountain, including a water-conducting layer at the lower part and a vegetation water-holding layer at the upper part, and plant plants with alternating growth periods or evergreen throughout the year on the water-holding layer.

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