Micro-arched false floor laying structure for underhand drift filling mining method

Abstract

The utility model relates to metal ore underground mining technical field especially downward approach filling mining method micro-arched false bottom laying structure, including setting in the first layer reinforcement net of below, setting in the second layer reinforcement net of above and setting in the surrounding rock of stope both sides prevent the steel bar of falling off, and the first layer reinforcement net is connected with the second layer reinforcement net through a plurality of vertical reinforcement, and the first layer reinforcement net is arranged in the arch shape, and the second layer reinforcement net is horizontally arranged, the end of prevent the steel bar of falling off close to stope is located above the second layer reinforcement net, and the first layer reinforcement net is fixedly connected with the second layer reinforcement net on prevent the steel bar of falling off, prevent false bottom from falling off, through setting the first layer reinforcement net as micro-arched structure combination bottom micro-arched broken stone cushion, make false bottom bottom filling body by traditional tensile state changes for compression state, make full use of filling material compressive strength far higher than the characteristics of tensile strength, significantly improved the stress state of false bottom, effectively avoided filling body cracking and falling off, improved the structure stability and security of false bottom.

Description

Technical Field

[0001] This utility model relates to the field of underground mining technology for metal mines, and in particular to a micro-arched false bottom laying structure for a downward-facing horizontal-path filling mining method. Background Technology

[0002] In underground metal mining, especially in the extraction of high-value minerals such as gold, upward horizontal approach backfilling and downward approach backfilling methods are commonly used to effectively control ore loss rates and improve operational safety. In upward approach backfilling, an artificial false floor is constructed before backfilling the first ore body, and workers operate under this artificial false floor during the final mining of the next section. In downward approach backfilling, artificial false floors are constructed for all layers, and workers operate under this artificial false floor during the mining of each layer. The stability of the artificial false floor directly affects operational safety.

[0003] To effectively improve the stability of artificial false bottoms, domestic and international mining companies and related research institutions have focused on optimizing the performance of backfill materials, construction techniques, structure, and controlling blasting damage, achieving significant results. After the artificial false bottom is exposed, the self-weight of the overlying backfill is mainly supported by the surrounding rock and the reinforcement within the false bottom. The reinforcement and backfill material within the false bottom are under tension. The backfill material, being a rock-like material, has a tensile strength far lower than its compressive strength, leading to significant backfill material detachment and threatening worker safety.

[0004] In view of the shortcomings of existing technologies, there is an urgent need for a reasonable false bottom arrangement method and construction process to change the stress state of the false bottom filling body, make full use of the compressive strength of the false bottom filling material, and improve the stability of the false bottom. Utility Model Content

[0005] Technical objective: In order to overcome the shortcomings of the existing technology, this utility model provides a micro-arched false bottom laying structure for the downward-entry filling mining method, which makes full use of the compressive strength of the filling material, improves the stress state of the false bottom, enhances the stability of the false bottom, and prevents the false bottom from falling off.

[0006] Technical Solution: To achieve the above objectives, this utility model discloses a micro-arched false bottom laying structure for the downward-entry filling mining method, comprising a steel reinforcement structure. The steel reinforcement structure includes a first-layer steel reinforcement mesh at the bottom, a second-layer steel reinforcement mesh at the top, and anti-detachment steel reinforcement bars in the surrounding rock on both sides of the stope. The first-layer steel reinforcement mesh and the second-layer steel reinforcement mesh are connected by several vertical steel bars. The first-layer steel reinforcement mesh is arched, and the second-layer steel reinforcement mesh is horizontally arranged. The end of the anti-detachment steel reinforcement bar near the stope is located above the second-layer steel reinforcement mesh. The first-layer steel reinforcement mesh and the second-layer steel reinforcement mesh are fixedly connected to the anti-detachment steel reinforcement bar to prevent the false bottom from falling off.

[0007] Furthermore, the first layer of steel mesh is intermittently laid on the crushed stone cushion layer, which is also an arched structure with an arc that matches the first layer of steel mesh.

[0008] Furthermore, the anti-detachment steel bars extend downward at a certain angle in the surrounding rock on both sides of the mining area.

[0009] Furthermore, the first layer of steel mesh includes a first main bar extending along the width of the mining area and a plurality of first reinforcement bars intersecting with the first main bar, the plurality of first main bars being arranged at intervals along the length of the mining area.

[0010] Furthermore, the two ends of the first main reinforcing bar are bent toward the anti-detachment reinforcing bars on both sides and fixedly connected to the anti-detachment reinforcing bars.

[0011] Furthermore, the second-layer steel mesh includes a second main bar extending along the width of the mining area and a plurality of second reinforcement bars intersecting with the second main bar, the plurality of second main bars being spaced apart along the length of the mining area.

[0012] Furthermore, the two ends of the second main reinforcing bar are bent toward the anti-detachment reinforcing bars on both sides and fixedly connected to the anti-detachment reinforcing bars.

[0013] Furthermore, it also includes a filling structure constructed after the steel reinforcement structure is laid. The filling structure includes an initial filling and an upper filling. The initial filling height is L4, and the distance between the end of the anti-detachment steel reinforcement near the mining area and the bottom plate is L3. L4 is greater than L3.

[0014] Furthermore, the vertical reinforcing bars are connected to the first-layer and second-layer reinforcing meshes by bending at both ends; the diameter of the first main reinforcing bar is not less than the diameter of the first auxiliary reinforcing bar, and the two are connected by metal wire or directly welded; the diameter of the second main reinforcing bar is not less than the diameter of the second auxiliary reinforcing bar, and the two are connected by metal wire or directly welded.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. This utility model transforms the bottom filling material of the false bottom from a traditional tensile state to a compressive state by setting the first layer of steel mesh as a micro-arched structure combined with the bottom layer of micro-arched crushed stone cushion. It makes full use of the characteristic that the compressive strength of the filling material is much higher than its tensile strength, which significantly improves the stress state of the false bottom, effectively avoids cracking and falling off of the filling material, and improves the structural stability and operational safety of the false bottom.

[0017] 2. This utility model sets inclined downward extending anti-detachment steel bars in the surrounding rock on both sides of the mining area, and fixes the first layer of steel mesh and the second layer of steel mesh to the anti-detachment steel bars. At the same time, the ends of the anti-detachment steel bars are buried in the filling body or surrounding rock on both sides of the access mining area, forming a double anchoring mechanism, which effectively prevents the false bottom from falling off as a whole and greatly improves the reliability of the connection between the false bottom and the surrounding rock.

[0018] 3. This utility model has a simple structure and is easy to construct. It naturally forms an arched support foundation through a crushed stone cushion layer, with fewer construction procedures and lower costs, making it easy to promote and apply in mining sites. Attached Figure Description

[0019] Figure 1 This is a cross-sectional schematic diagram of the micro-arched false bottom paving structure in the embodiments of this application.

[0020] In the diagram, 1. First layer of steel mesh; 2. Second layer of steel mesh; 3. Anti-detachment steel bars; 4. Vertical steel bars; 5. Crushed stone cushion layer; 6. Initial filling; 7. Base slab. Detailed Implementation

[0021] The following is in conjunction with the appendix Figure 1 The principles and features of this utility model are described, and the examples given are only used to explain this utility model and are not intended to limit the scope of this utility model.

[0022] The micro-arched false bottom paving structure for down-entry filling mining is suitable for down-horizontal filling mining in underground metal mining. It includes a crushed stone cushion layer 5, a reinforced steel structure, and a filling structure. The crushed stone cushion layer 5 is laid on the stope floor 7, and the reinforced steel structure is laid on top of the crushed stone cushion layer 5. After the reinforced steel structure is laid, the stope is filled to form the filling structure. In this embodiment, the stope width is 3m and the height is 4m.

[0023] The crushed stone cushion layer 5 is laid on the leveled mine floor 7 and has an arched structure. In the width direction, the thickness of the crushed stone cushion layer 5 is not less than 100 mm at both ends and not less than 300 mm in the middle, forming a slightly arched state with a higher middle and lower sides.

[0024] The reinforced steel structure includes a first-layer steel mesh 1 at the bottom, a second-layer steel mesh 2 at the top, and anti-detachment steel bars 3 installed in the surrounding rock on both sides of the mining area. The first-layer steel mesh 1 and the second-layer steel mesh 2 are connected by several vertical steel bars 4. The end of the anti-detachment steel bar 3 closest to the mining area is located above the second-layer steel mesh 2, meaning that the anti-detachment steel bar 3 is higher than the first-layer steel mesh 1 and the second-layer steel mesh 2. Therefore, the first-layer steel mesh 1 and the second-layer steel mesh 2 are fixedly connected to the anti-detachment steel bar 3 to prevent the false bottom from falling off.

[0025] The first layer of reinforcing mesh 1 is an arched structure, high in the middle and low on both sides, forming a slightly arched structure. The first layer of reinforcing mesh 1 is spaced over the crushed stone cushion layer 5, and the curvature of the first layer of reinforcing mesh 1 and the crushed stone cushion layer 5 is consistent. In this embodiment, the first layer of reinforcing mesh 1 and the crushed stone cushion layer 5 are spaced 100mm apart. The first layer of reinforcing mesh 1 includes a first main bar parallel to the width direction of the mining area and several first auxiliary bars intersecting the first main bar. The several first main bars are spaced apart along the length direction of the mining area, and the several first auxiliary bars are spaced apart along the width direction of the mining area, thus forming a mesh structure. The diameter of the first main bar is not less than the diameter of the first auxiliary bars, and the two are connected by metal wire or directly welded. In this embodiment, the first main bar and the first auxiliary bars are perpendicular to each other, and both use φ12mm threaded steel, with a horizontal spacing of 300mm.

[0026] The second-layer steel mesh 2 is a horizontally arranged steel mesh, spaced above the first-layer steel mesh 1. Its mesh structure is similar to that of the first-layer steel mesh 1, including second main bars extending along the width of the mining area and several second auxiliary bars intersecting the second main bars. The second main bars are spaced apart along the length of the mining area, and the second auxiliary bars are spaced apart along the width of the mining area, thus forming the mesh structure. The diameter of the second main bars is not less than the diameter of the second auxiliary bars, and the two are connected by metal wire or directly welded. In this embodiment, the second main bars and the second auxiliary bars are perpendicular to each other, both using φ12mm threaded steel, and the horizontal spacing is 300mm.

[0027] Several anti-detachment reinforcing bars 3 are spaced apart along the length of the mining area and drilled downwards into the surrounding rock at a certain angle. The two ends of the first main reinforcing bar are bent towards the anti-detachment reinforcing bars 3 on both sides and fixedly connected to the ends of the anti-detachment reinforcing bars 3 (e.g., by welding). Similarly, the two ends of the second main reinforcing bar are bent towards the anti-detachment reinforcing bars 3 on both sides and fixedly connected to the anti-detachment reinforcing bars 3 (e.g., by welding). This structural arrangement ensures the stable fixation of the first layer of reinforcing mesh 1 and the second layer of reinforcing mesh 2, greatly reducing the risk of false bottom detachment. The height of the end of the anti-detachment reinforcing bar 3 closest to the mining area from the bottom plate 7 is L3, which is 1.0m in this embodiment. The anti-detachment reinforcing bars 3 are made of round steel, and their arrangement density can be adjusted according to the surrounding rock conditions. The spacing between adjacent anti-detachment reinforcing bars 3 can be 600mm~1200mm; in this embodiment, the spacing is 900mm.

[0028] There are two ways to connect the first main reinforcement bar and the anti-detachment reinforcement bar 3: One is a one-to-one fixed connection, where the end of each first main reinforcement bar is welded to one anti-detachment reinforcement bar 3; the other is that multiple adjacent first main reinforcement bars are fixedly connected to the same anti-detachment reinforcement bar 3, where the bent portions of some first main reinforcement bars are inclined towards the anti-detachment reinforcement bar 3. The specific method used can be flexibly determined based on the surrounding rock conditions and bearing requirements. When the surrounding rock conditions are good, multiple main reinforcement bars can share one anti-detachment reinforcement bar 3 to reduce the number of boreholes and improve construction efficiency; when the surrounding rock conditions are poor or the bearing requirements are high, a one-to-one connection method can be used to improve connection reliability. The connection method between the second main reinforcement bar and the anti-detachment reinforcement bar 3 is the same as that of the first main reinforcement bar and will not be described again.

[0029] Vertical reinforcing bars 4 are connected to the first-layer reinforcing mesh 1 and the second-layer reinforcing mesh 2 by bending their ends. The bent ends of the vertical reinforcing bars 4 are hooked onto the first-layer reinforcing mesh 1 and the second-layer reinforcing mesh 2 respectively, forming a connection. In this embodiment, the length of the vertical reinforcing bars 4 located in the middle is 100mm, and the length of the vertical reinforcing bars 4 located on both sides is 300mm. The mesh size is 600mm × 600mm, meaning the minimum distance between the first-layer reinforcing mesh 1 and the second-layer reinforcing mesh 2 is 100mm, and the maximum distance is 300mm. It can be understood that the specific values ​​of the above distances can be adjusted according to the design requirements of the mining area width and the false bottom thickness. The minimum distance L1 between the first-layer reinforcing mesh 1 and the second-layer reinforcing mesh 2 is 100mm~150mm, and the maximum distance L2 is 250mm~350mm.

[0030] The filling structure includes the initial filling 6 and the upper filling. The initial filling 6 uses high-proportion filling material or concrete, and its height is L4. L4 is greater than the height L3 of the anti-detachment steel bar 3 near the stope from the bottom plate 7. That is, the anti-detachment steel bar 3 near the stope is embedded in the initial filling 6 to further prevent the false bottom from falling off. In this embodiment, L4 is 1.5m. After the initial filling 6 is completed, a second filling is carried out, and the second filling uses filling material with normal proportion.

[0031] The construction process of the false bottom laying structure of this utility model is as follows:

[0032] S1. After the mining is completed, level the bottom plate of the mining area 7, and flatten an appropriate amount of crushed ore into a slightly arched state with a high center and low sides to form a crushed stone cushion layer 5.

[0033] S2. Construct anti-detachment reinforcing bars 3 in the surrounding rock on both sides of the stope. Drill holes in the surrounding rock on both sides of the stope at a height L3 = 1.0m from the bottom plate 7, and drive the anti-detachment reinforcing bars 3 downwards into the surrounding rock at a certain angle. The anti-detachment reinforcing bars 3 are arranged at intervals along the length of the stope, with a spacing of 900mm between adjacent anti-detachment reinforcing bars 3.

[0034] S3. Lay the first layer of reinforcing mesh 1 in the mining area. The first layer of reinforcing mesh 1 is laid on the crushed stone cushion layer 5, and its curvature is consistent with that of the crushed stone cushion layer 5. The distance between the first layer of reinforcing mesh 1 and the crushed stone cushion layer 5 is 100mm. During laying, first weld and fix the first main reinforcement to the anti-detachment reinforcement 3, and then lay the first auxiliary reinforcement in a direction perpendicular to the first main reinforcement. The intersection of the first main reinforcement and the first auxiliary reinforcement is connected by binding with metal wire. The horizontal spacing between the first main reinforcement and the first auxiliary reinforcement is 300mm. Three adjacent first main reinforcements are fixedly welded to the same anti-detachment reinforcement 3.

[0035] S4. After the first layer of reinforcing mesh 1 is laid, the second layer of reinforcing mesh 2 is laid on top of it. The laying method is similar to that of the first layer of reinforcing mesh 1. After the second layer of reinforcing mesh 2 is laid, the two ends of the vertical reinforcing bars 4 are bent and hooked onto the first layer of reinforcing mesh 1 and the second layer of reinforcing mesh 2 respectively to form a connection. The mesh size of the vertical reinforcing bars 4 is 600mm×600mm.

[0036] S5. The access stope is filled in two stages. The first filling 6 uses high-mix filling material or concrete, with a filling height L4 of 1.5m. The first filling 6 must cover the end of the anti-detachment steel bar 3 closest to the stope (i.e., L4 > L3), so that the end of the anti-detachment steel bar 3 is anchored within the first filling 6. After the first filling 6 has cured to the design strength, the second filling is carried out, using filling material with the normal mix ratio.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A micro-arched false bottom paving structure for down-pass filling mining method, characterized in that, The system includes a steel reinforcement structure, comprising a first-layer steel reinforcement mesh (1) at the bottom, a second-layer steel reinforcement mesh (2) at the top, and anti-detachment steel reinforcement (3) in the surrounding rock on both sides of the mining area. The first-layer steel reinforcement mesh (1) and the second-layer steel reinforcement mesh (2) are connected by several vertical steel bars (4). The first-layer steel reinforcement mesh (1) is arched, and the second-layer steel reinforcement mesh (2) is horizontal. The anti-detachment steel reinforcement (3) is located above the second-layer steel reinforcement mesh (2) at one end near the mining area. The first-layer steel reinforcement mesh (1) and the second-layer steel reinforcement mesh (2) are fixedly connected to the anti-detachment steel reinforcement (3) to prevent the false bottom from falling off.

2. The micro-arched false bottom paving structure for down-pass filling mining method according to claim 1, characterized in that, The first layer of steel mesh (1) is intermittently covered on the crushed stone cushion layer (5), and the crushed stone cushion layer (5) is also an arched structure with an arc that matches the first layer of steel mesh (1).

3. The micro-arched false bottom paving structure for down-pass filling mining method according to claim 1, characterized in that, The anti-detachment steel bar (3) extends downward at a certain angle in the surrounding rock on both sides of the mining area.

4. The micro-arched false bottom paving structure for down-pass filling mining method according to claim 3, characterized in that, The first layer of steel mesh (1) includes a first main bar extending along the width of the mining area and a number of first reinforcement bars intersecting with the first main bar. The number of first main bars are arranged at intervals along the length of the mining area.

5. The micro-arched false bottom laying structure for down-pass filling mining method according to claim 4, characterized in that, The two ends of the first main bar are bent toward the anti-detachment steel bars (3) on both sides and fixedly connected with the anti-detachment steel bars (3).

6. The micro-arched false bottom laying structure for down-pass filling mining method according to claim 4, characterized in that, The second-layer steel mesh (2) includes a second main bar extending along the width of the mining area and a number of second reinforcement bars intersecting with the second main bar. The number of second main bars are arranged at intervals along the length of the mining area.

7. The micro-arched false bottom paving structure for down-pass filling mining method according to claim 6, characterized in that, The two ends of the second main bar are bent toward the anti-detachment steel bars (3) on both sides and fixedly connected with the anti-detachment steel bars (3).

8. The micro-arched false bottom paving structure for down-pass filling mining method according to claim 3, characterized in that, It also includes a filling structure constructed after the steel reinforcement structure is laid. The filling structure includes an initial filling (6) and an upper filling. The height of the initial filling (6) is L4. The distance between the end of the anti-detachment steel reinforcement (3) near the mining area and the bottom plate (7) is L3. L4 is greater than L3.

9. The micro-arched false bottom paving structure for down-pass filling mining method according to claim 6, characterized in that, The vertical reinforcing bars (4) are connected to the first layer of reinforcing mesh (1) and the second layer of reinforcing mesh (2) by bending at both ends; the diameter of the first main reinforcing bar is not less than the diameter of the first reinforcement bar, and the two are connected by metal wire or directly welded; the diameter of the second main reinforcing bar is not less than the diameter of the second reinforcement bar, and the two are connected by metal wire or directly welded.

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