Mine pit backfilling and foundation treatment structure

Abstract

The utility model relates to a mine pit backfilling and foundation treatment structure. According to the scheme, the mine pit backfilling and foundation treatment structure comprises a high polymer gravel three-dimensional reinforcing structure, backfilling soil, a polyvinyl chloride film, a horizontal drainage cushion layer, a drainage plate, a disc pit tunnel and an observation marker post. Wherein the disc pit tunnel is formed by spiral cutting along the pit wall of a mine pit and used for transporting backfill soil and materials, curbs are arranged on the outer side, and stand columns are arranged in the disc pit tunnel; mine pit tail mud and an external soil body are adopted as backfill soil, and layered paving and rolling and vacuum combined surcharge preloading treatment are carried out; the middle-shallow-layer foundation forms a three-dimensional reinforced structure through criss-cross gravel drainage channels in combination with high polymer grouting, and the deep-layer foundation achieves vacuum preloading drainage through polyvinyl chloride film sealing and drainage plates. The problem of solid waste stockpiling is solved through tail mud resource utilization, the construction efficiency is improved by means of the disc pit tunnel, the foundation bearing capacity is remarkably improved by combining the layered drainage and three-dimensional reinforcement technology, and the method has the advantages of being convenient to construct, environmentally friendly, economical, high in foundation stability and the like.

Description

Technical Field

[0001] This utility model relates to the field of mine restoration technology, specifically to mine pit backfilling and foundation treatment structures. Background Technology

[0002] With the long-term development of mining, especially the large-scale mining of granite and other stone materials, a large number of concave pits (referred to as "mine pits") have been formed. Taking Fujian Province as an example, there are more than 100 existing mine pits of various types, ranging in area from hundreds to tens of thousands of square meters. The slope height is mostly tens to hundreds of meters, and the slope is generally greater than 75°, with some areas being almost vertical. These mine pits generally have the following problems:

[0003] 1. Significant geological safety hazards: The rock mass of the mine pit slope is exposed and loosely structured. It is affected by weathering and rainwater erosion for a long time, which makes it prone to landslides, collapses and other disasters, threatening the safety of surrounding personnel and facilities; some mine pits accumulate water to form high potential energy water bodies, which further aggravates the risk of slope instability.

[0004] 2. The Challenge of Solid Waste Storage: Tailings generated during granite mining (a mixture of stone powder and water with particle sizes mostly less than 75μm) are characterized by high compressibility and low shear strength. Traditional treatment methods require large-scale land storage, which not only occupies scarce land resources but also poses environmental risks of leachate leakage polluting the soil and groundwater. To date, my country has accumulated billions of tons of mine tailings, with a huge amount being added every year, resulting in severe disposal pressure.

[0005] 3. Conflict between ecological restoration and land use: The areas where mine pits are located are mostly ecologically fragile areas with severe desertification and scarce soil resources. Traditional backfilling requires a large amount of external soil, which exacerbates the problem of soil shortage in the region. However, existing mine pit backfilling technology has defects such as low construction efficiency and poor foundation treatment effect. For example, deep backfilled soil foundations have long drainage paths and rely on long natural consolidation periods, which can easily lead to later settlement. The bearing capacity of medium and shallow foundations is insufficient, making it difficult to meet the needs of engineering construction.

[0006] In addition, in traditional mine construction, material transportation often relies on temporary stepped passages or vertical hoisting, which results in problems such as low transportation efficiency, high cost, and poor safety. Furthermore, the excavated rock waste is not effectively recycled, leading to resource waste.

[0007] To address the aforementioned problems, there is an urgent need for a mine pit backfilling technology solution that integrates safe and efficient construction, tailings resource utilization, and foundation reinforcement treatment to solve the challenges of geological safety, environmental protection, and land reuse in mine pit remediation. This invention, through the innovative design of a pit tunnel transportation system, a layered vacuum combined surcharge preloading process, and a polymer-reinforced crushed stone three-dimensional reinforcement structure, achieves the recycling of tailings, ensuring they return to their source. This significantly improves backfilling efficiency and foundation performance, providing reliable support for mine pit ecological restoration and subsequent engineering construction. Utility Model Content

[0008] The purpose of this utility model is to address the aforementioned problems in the existing technology by providing a mine pit backfilling and foundation treatment structure. This structure achieves efficient mine pit backfilling and foundation strengthening through a combination of a pit tunnel transportation system, tailings layered backfilling, vacuum combined surcharge preloading, and a polymer crushed stone three-dimensional reinforcement structure.

[0009] To achieve the aforementioned objectives, this utility model adopts the following technical solution: the mine pit backfilling and foundation treatment structure includes:

[0010] The polymer-reinforced crushed stone three-dimensional reinforcement structure is set in the shallow to medium-depth backfill foundation. It consists of crisscrossing rectangular crushed stone layers. The crushed stone layers include horizontal and vertical crushed stone drainage channels to quickly drain water from the backfill foundation. Grouting pipes are pre-embedded in the crushed stone layers for polymer grouting after the foundation drainage is completed to form a three-dimensional reinforcement structure.

[0011] Backfill soil is made from tailings and foreign soil generated during mining operations, used to fill the mine pit and form a backfill soil foundation.

[0012] Polyvinyl chloride film is laid in deep backfilled soil foundations to seal the foundations and reinforce them with vacuum combined surcharge preloading.

[0013] A horizontal drainage layer, placed below the polyvinyl chloride film, is used to collect moisture discharged during deep foundation vacuum combined surcharge preloading;

[0014] Drainage boards are spaced out in the deep backfilled soil foundation for vertical drainage of the foundation;

[0015] The Pankeng Tunnel is formed by spiraling downwards along the mine pit wall. It is used to transport backfill soil and construction materials and to provide working space. The Pankeng Tunnel is equipped with curb stones on the outside and support columns inside.

[0016] Horizontal observation benchmarks are set on both sides of each layer of vacuum combined surcharge preloading foundation to observe the horizontal displacement of the foundation;

[0017] Vertical observation beacons are set at the centerline of each layer of vacuum combined surcharge preloading foundation to monitor foundation settlement.

[0018] Furthermore, the cross-sectional side length of the crushed stone layer in the polymer crushed stone three-dimensional reinforcement structure is 50-100cm, the horizontal and vertical spacing is 3-5m, and the height is set from the middle of the mine pit to the top of the mine pit.

[0019] Furthermore, the moisture content of the backfill soil is controlled within ±3% of the optimum moisture content.

[0020] Furthermore, three layers of polyvinyl chloride film are laid, and the vacuum degree under the film reaches more than 80 kPa.

[0021] Furthermore, the thickness of the horizontal drainage layer is 30–50 cm.

[0022] Furthermore, the drainage boards are spaced 0.8 to 1 m apart, and the boards are 9 to 12 m long.

[0023] Furthermore, both horizontal and vertical observation markers are set up every 50m.

[0024] Furthermore, the slope of the Pankeng Tunnel is less than 6%, the width is not less than 6m, the height is 3-5m, and the curbstone is a continuous rock mass reserved on the outside of the Pankeng Tunnel with a thickness of 5-10cm.

[0025] Furthermore, the columns adopt a square cross-section with a length of 1-2m and a thickness of 20-50cm, and the column spacing is 5-8m.

[0026] Furthermore, the surcharge load of vacuum combined surcharge preloading is directly filled in layers using backfill soil.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. Highly efficient and safe construction: The pit tunnel design, with a slope of less than 6% and a width of ≥6m, replaces the traditional stepped transportation method, significantly improving transportation efficiency and shortening the construction period. Curb stones are installed on the outside, and pillars are placed inside, reducing excavation volume. Cut stones are recyclable, lowering costs.

[0029] 2. Excellent environmental benefits: Using mine tailings as the main backfill material and controlling the moisture content at the optimal value of ±3% solves the problem of tailings storage, realizes the recycling of solid waste, and takes into account both ecology and economy.

[0030] 3. Superior Foundation Treatment: The deep layer is sealed with three layers of PVC film, combined with drainage boards and a horizontal drainage cushion layer, and a vacuum degree of ≥80kPa accelerates consolidation. The middle and shallow layers have a three-dimensional reinforcement structure of polymer crushed stone, with pre-embedded grouting pipes to inject polymer to enhance bearing capacity. Layered construction is used, with small layers paved and compacted, and large layers subjected to vacuum combined with surcharge preloading, using the backfill soil itself as surcharge to reduce post-construction settlement.

[0031] 4. Strong risk control: Horizontal and vertical observation markers are set every 50m to monitor foundation displacement and settlement in real time. Construction is suspended when the levels exceed the standards to avoid slope instability and foundation collapse.

[0032] In summary, this utility model effectively solves existing problems related to mine pit backfilling construction, environmental protection, and foundation through structural and technological innovation, demonstrating significant technological progress. Attached Figure Description

[0033] Figure 1 This is a side view of the construction structure for mine pit backfilling;

[0034] Figure 2 It is a three-dimensional view of the construction structure for mine pit backfilling;

[0035] Figure 3 It is a three-dimensional view of a polymer crushed stone reinforcement structure;

[0036] Figure 4 This is a side view of the foundation treatment structure;

[0037] Figure 5 This is a schematic diagram of a vacuum combined loading preloading embodiment;

[0038] Figure 6 This is a schematic diagram of the drainage board arrangement in an embodiment;

[0039] Figure 7 This is a schematic diagram of the three-dimensional reinforced polymer crushed stone structure of the embodiment.

[0040] In the diagram, 01 is the three-dimensional reinforcement structure of polymer crushed stone; 02 is the backfill soil; 03 is the polyvinyl chloride film; 04 is the horizontal drainage cushion layer; 05 is the drainage board; 11 is the horizontal observation pole; 12 is the vertical observation pole; 21 is the top surface of the mine pit; 22 is the bottom of the mine pit; 23 is the wall of the mine pit; 24 is the pit tunnel; 25 is the transport vehicle; 26 is the curb stone; 27 is the column; 6 is the horizontal crushed stone drainage channel; 7 is the vertical crushed stone drainage channel; 8 is the remaining part of the backfill tailings; and 9 is the mine pit. Detailed Implementation

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model are within the protection scope of the present utility model.

[0042] Those skilled in the art should understand that in the disclosure of this utility model, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as a limitation of this utility model.

[0043] Example 1

[0044] like Figure 1-7As shown, this mine pit backfill and foundation treatment structure is used to fill the mine pit and reinforce the backfilled soil foundation, including:

[0045] Polymer crushed stone three-dimensional reinforcement structure 01: Set in the shallow to medium layer of backfilled soil foundation, it is used to quickly drain the water in the backfilled soil foundation, and grouting forms a three-dimensional reinforcement structure to further improve the bearing capacity of the foundation;

[0046] In this embodiment, the polymer crushed stone three-dimensional reinforcement structure 01 is composed of crisscrossing cuboid crushed stone layers (such as horizontal crushed stone drainage channels 6 and vertical crushed stone drainage channels 7). The cross-sectional side length of the crushed stone layer is 50-100cm, the horizontal and vertical spacing is 3-5m, and the height is set from the middle of the mine pit to the top of the mine pit. This is used to quickly drain the water in the backfill foundation soil and improve the soil strength and bearing capacity. The drainage structure needs to be pre-embedded with grouting pipes. After the foundation drainage is completed, polymer grouting is carried out through the grouting pipes to form a three-dimensional polymer crushed stone reinforcement structure, which further improves the foundation bearing capacity.

[0047] Backfill 02: Tailings formed from mining operations (such as...) Figure 3 The remaining part of the backfill (tailings 8) and foreign soil are used to fill the mine pit and form a backfill foundation.

[0048] In this embodiment, the backfill soil 02 is tailings formed from mining and external soil. Before backfilling, the moisture content needs to be controlled within ±3% of the optimum moisture content. It is transported to the mine pit by transport vehicle 25 along the pit tunnel 24. It is reinforced by layering and leveling and vibrating compaction in each small layer of 0.5 to 1.5m, and layering vacuum combined surcharge preloading in a large layer of 8 to 12m.

[0049] Polyvinyl chloride film 03: Used for sealing deep backfilled soil foundations and for vacuum combined surcharge preloading reinforcement;

[0050] In this embodiment, three layers of polyvinyl chloride film 03 need to be laid, and the vacuum degree under the film reaches more than 80 kPa, which is used to seal the deep backfill foundation and carry out vacuum combined surcharge preloading reinforcement.

[0051] Horizontal drainage cushion layer 04: Used to collect water discharged during vacuum combined surcharge preloading of deep foundations;

[0052] In this embodiment, the horizontal drainage cushion layer 04 has a thickness of 30-50cm and is used to collect the water discharged during the deep foundation vacuum combined surcharge preloading.

[0053] Drainage board 05: Used for vertical drainage of deep backfilled soil foundations;

[0054] In this embodiment, the drainage boards 05 are spaced 0.8-1m apart and are 9-12m long, and are used for vertical drainage of deep backfilled soil foundations.

[0055] Horizontal observation beacon 11: Set on both sides of each layer of vacuum combined surcharge preloading foundation to observe the horizontal displacement of the foundation;

[0056] In this embodiment, horizontal observation markers 11 are set on both sides of each layer of vacuum combined surcharge preloading foundation to observe the horizontal displacement of the foundation, with one marker set every 50m. Surcharge preloading is achieved by directly using backfill soil 02 to fill the preloading load in layers. The total load is controlled within the design requirements and must not exceed the allowable bearing capacity of the foundation. This is existing technology and will not be described in detail here.

[0057] Vertical observation beacon 12: set at the centerline of each layer of vacuum combined surcharge preloading foundation, used to observe the settlement of the foundation;

[0058] In this embodiment, vertical observation markers 12 are set at the centerline of each layer of vacuum combined surcharge preloading foundation to observe the settlement of the foundation, and one is set every 50m.

[0059] Top surface of the mine pit 21: The elevation of the backfill soil 02 after backfilling is completed. After the backfilling construction is completed, it can be used as the site foundation for the project construction.

[0060] 22 at the bottom of the mine pit: the starting point for backfilling soil 02.

[0061] Mine pit wall 23: Working face for cutting the pan-pit tunnel 24.

[0062] Pankeng Tunnel 24: A tunnel formed by spiraling downwards along the mine pit wall, used for transporting backfill soil 02 and construction materials, as well as providing working space.

[0063] In this embodiment, after the water in the mine pit is pumped out and the unstable rock mass is cleared, the Pankeng Tunnel 24 is formed by using a large electric saw to cut the mine pit wall rock mass, spiraling downwards to the bottom of the pit. The tunnel slope is less than 6%, the width is more than 6m, and the height is 3-5m, ensuring normal passage for personnel, vehicles, construction equipment, and materials. The cut stone is transported out by vehicles and equipment and can be collected as building materials.

[0064] Transport vehicle 25: Used to transport backfill soil to the bottom of the mine pit 22.

[0065] Curbstone 26: Located on the outside of the Pankeng Tunnel 24 to ensure driving safety.

[0066] In this embodiment, the curbstone 26 is a continuous rock mass with a certain thickness left when cutting the pan-pit tunnel 24. It is set on the outside of the pan-pit tunnel 24 and has a thickness of 5 to 10 cm to ensure driving safety.

[0067] Column 27: Used to support the pit tunnel 24, with a square cross-section, a length of 1-2m, a thickness of 20-50cm, and a column spacing of 5-8m.

[0068] Example 2

[0069] Based on the same concept, this embodiment proposes a construction method for realizing mine pit backfilling and foundation treatment structures based on Embodiment 1. The specific steps are as follows:

[0070] 1) Drain the water in mine pit 9, clear the unstable rock mass in the pit, and cut downwards along the pit wall to form a spiral tunnel. During this process, curb stones 26 and pillars 27 need to be set up.

[0071] 2) Transport vehicles 25 are used to transport the material to the mine pit along the pan-pit tunnel 24. The material is then leveled and vibrated and compacted in layers of 0.5 to 1.5m for each small layer and reinforced by vacuum combined surcharge preloading in layers of 8 to 12m for each large layer, until the backfill foundation treatment of the lower part of the mine pit is completed.

[0072] 3) During the backfilling process, a crisscrossing three-dimensional crushed stone drainage structure (such as horizontal crushed stone drainage channel 6 and vertical crushed stone drainage channel 7) is set in the middle and upper part of the foundation to quickly drain the water in the backfilled foundation soil, improve the soil strength and bearing capacity. At the same time, grouting pipes need to be pre-embedded in the crushed stone drainage structure. After the foundation drainage is completed, polymer grouting is carried out through the grouting pipes to form a three-dimensional polymer crushed stone reinforcement structure, which further improves the bearing capacity of the foundation.

[0073] The parts of this utility model not described in detail are existing technologies, therefore they are not described in detail here.

[0074] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0075] Although this document uses a considerable amount of technical terminology, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any additional limitation would contradict the spirit of this utility model.

[0076] This utility model is not limited to the above-described preferred embodiment. Anyone can derive other forms of products under the guidance of this utility model. However, regardless of any changes made to their shape or structure, any technical solution that is the same as or similar to this utility model falls within the protection scope of this utility model.

Claims

1. A mine pit backfilling and foundation treatment structure, characterized in that, include: A polymer-reinforced three-dimensional crushed stone structure (01) is set in a shallow backfilled soil foundation and consists of a crisscrossing rectangular crushed stone layer. The crushed stone layer includes a horizontal crushed stone drainage channel (6) and a vertical crushed stone drainage channel (7) for quickly draining water from the backfilled soil foundation. A grouting pipe is pre-embedded in the crushed stone layer for polymer grouting to be performed through the grouting pipe after the foundation drainage is completed to form a three-dimensional reinforcement structure. Backfill soil (02) is made from tailings and foreign soil generated during mining operations. It is used to fill the mine pit and form a backfill soil foundation. Polyvinyl chloride film (03) is laid in the deep backfilled soil foundation to seal the foundation and carry out vacuum combined surcharge preloading reinforcement; A horizontal drainage layer (04) is provided below the polyvinyl chloride film (03) to collect the water discharged during deep foundation vacuum combined surcharge preloading; Drainage boards (05) are spaced out in the deep backfilled soil foundation for vertical drainage of the foundation; The Pankeng Tunnel (24) is formed by spiraling downwards along the pit wall (23) of the mine. It is used to transport backfill soil (02) and construction materials, and to provide working space. The Pankeng Tunnel (24) is equipped with curb stones (26) on the outside and with support columns (27) inside. Horizontal observation beacons (11) are set on both sides of each layer of vacuum combined surcharge preloading foundation to observe the horizontal displacement of the foundation; Vertical observation markers (12) are set at the centerline of each layer of vacuum combined surcharge preloaded foundation to observe the settlement of the foundation.

2. The mine pit backfilling and foundation treatment structure according to claim 1, characterized in that, The cross-sectional length of the crushed stone layer of the polymer crushed stone three-dimensional reinforcement structure (01) is 50-100cm, the horizontal and vertical spacing is 3-5m, and the height is set from the middle of the mine pit to the top surface of the mine pit (21).

3. The mine pit backfilling and foundation treatment structure according to claim 1, characterized in that, The moisture content of the backfill soil (02) is controlled within ±3% of the optimum moisture content.

4. The mine pit backfilling and foundation treatment structure according to claim 1, characterized in that, The polyvinyl chloride film (03) is laid in three layers, and the vacuum degree under the film reaches more than 80 kPa.

5. The mine pit backfilling and foundation treatment structure according to claim 1, characterized in that, The thickness of the horizontal drainage pad (04) is 30-50cm.

6. The mine pit backfilling and foundation treatment structure according to claim 1, characterized in that, The drainage boards (05) are spaced 0.8 to 1 m apart and are 9 to 12 m long.

7. The mine pit backfilling and foundation treatment structure according to claim 1, characterized in that, The horizontal observation marker (11) and the vertical observation marker (12) are set up every 50m.

8. The mine pit backfilling and foundation treatment structure according to any one of claims 1-7, characterized in that, The slope of the Pankeng Tunnel (24) is less than 6%, the width is not less than 6m, and the height is 3 to 5m. The curbstone (26) is a continuous rock mass reserved on the outside of the Pankeng Tunnel (24) with a thickness of 5 to 10cm.

9. The mine pit backfilling and foundation treatment structure according to any one of claims 1-7, characterized in that, The column (27) has a square cross-section with a length of 1 to 2 m and a thickness of 20 to 50 cm. The column spacing is 5 to 8 m.

10. The mine pit backfilling and foundation treatment structure according to any one of claims 1-7, characterized in that, The vacuum combined surcharge preloading load is directly filled in layers using the backfill soil (02).

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