Downward access artificial roof construction method

Abstract

The invention discloses a construction method of a downward access artificial roof, and belongs to the technical field of artificial roofs. The method comprises the following steps: step 1, drift leveling: after a filling false roof drift is excavated, carrying out crushing treatment on residual pumice stones on two sides, and carrying out drift bottom cleaning and field leveling work; 2, laying bottom bars, wherein the bottom bars are arranged in a double-layer reinforcing mesh arrangement mode of transverse bars, longitudinal bars and meshes, and the meshes are flexible meshes; 3, hanging bar construction is conducted, wherein transverse tie bars are arranged at the positions, 1.8 m high, above the two sides of the roadway, and the hanging bars are welded to the bottom bar main bars and between the transverse tie bars; and fourthly, cemented filling is conducted, the artificial retaining wall is built, and after the artificial retaining wall reaches the construction standard, filling body pouring is conducted. The method can be used for operation in mining environments such as ore body surrounding rock crushing, joint fissure development and poor stability, safe and efficient ore body stoping is achieved, and the method has the advantages of being small in engineering amount, small in steel and cement consumption, low in construction cost, high in safety and reliability, simple in structure and wide in practicability.

Description

Technical Field

[0001] The invention relates to the technical field of artificial false ceilings, and more specifically to a method for constructing a downward approach artificial false ceiling. Background Art

[0002] According to the mining technical conditions, due to the characteristics of the ore body such as broken surrounding rock, developed joints and fissures, and poor stability, there are major safety hazards in the process of approach excavation. Even if the ordinary upward approach filling mining method is adopted, it is difficult to ensure the safety of approach mining. It is advisable to adopt the downward approach filling mining method to recover the broken ore body.

[0003] The mining sequence of the downward approach cemented filling mining method is from top to bottom, and the mining operation of the next layer is carried out under the protection of the bearing layer. At present, the artificial false roof of the downward horizontal approach filling mining usually uses concrete as the false roof for pouring. The required amount of gravel, sand, cement and other materials is large, and there are problems such as unreasonable reinforcement ratio, which leads to poor economy and safety of the artificial false roof. Therefore, how to provide a safe, economical and efficient artificial false roof construction method with simple structure, convenient construction, reliable performance, safety and good effect, and wide practicability. This technology provides a solution and technology in engineering practice. Summary of the invention

[0004] 1. Technical problem to be solved by the invention

[0005] In view of the defects and shortcomings of the prior art, the present invention provides a method for constructing an artificial false roof for a downward approach. The present invention has the advantages of simple structure, convenient construction, reliable performance, good safety performance, good effect, and wide applicability. A method for constructing an artificial false roof for a downward approach is provided, which can be used for operations in mining environments such as broken surrounding rock, developed joints and fissures, and poor stability of the ore body, to achieve safe and efficient recovery of the ore body, and has the advantages of small engineering volume, small amount of steel and cement used, low construction cost, high safety and reliability.

[0006] 2. Technical solution

[0007] In order to achieve the above object, the technical solution provided by the present invention is:

[0008] A method for constructing an artificial false roof for a downward approach of the present invention comprises the following steps:

[0009] Step 1: Smooth the approach:

[0010] After the false roof access road is excavated, the floating stones remaining on both sides are crushed, the waste rocks and accumulated water in the access road need to be handled, and the bottom of the access road needs to be cleared and leveled;

[0011] Step 2: Laying of bottom reinforcement:

[0012] The bottom reinforcement adopts a double-layer steel mesh arrangement of transverse and longitudinal reinforcement plus mesh, and the mesh adopts a flexible mesh;

[0013] Step 3: Construction of hanging bars:

[0014] Horizontal tie bars are arranged at a height of 1.8m above the two sides of the tunnel, and the hanger bars are welded between the bottom reinforcement and the horizontal tie bars. The spacing between the hanger bars in the middle of the approach is appropriately increased;

[0015] Step 4: Bonding filling, building artificial retaining walls, and pouring the filling body after the artificial retaining walls meet the construction standards:

[0016] An artificial false roof construction method is adopted in which the key layer is filled with graded tailings with high ash-sand ratio cementation and the top is filled with full tailings with low ash-sand ratio cementation.

[0017] Furthermore, in the step 1, the dimensions of the excavation approach are: width 4.0~5.0m, height 4.0m, and the approach shape is rectangular.

[0018] Furthermore, in the step 2, the bottom reinforcement is arranged with a double-layer steel mesh, that is, transverse and longitudinal reinforcements plus mesh, the transverse and longitudinal reinforcements are made of 12mm threaded steel, the bottom reinforcement must not be less than 100mm away from the bottom plate, the mesh is laid on the transverse and longitudinal reinforcements, the flexible mesh uses a 2.2mm diameter flexible mesh wire, the mesh size is 50mm×50mm, the mesh uses galvanized chain link fence, and the length of a single mesh is 5100mm×1600mm.

[0019] Furthermore, in the step three, holes are drilled at a height of 1.8m on both sides of the tunnel, and the hole depth is greater than 300mm. The two ends of the transverse tie bars are embedded in the drilled holes at both ends to fix the hanger bars. The transverse tie bars are made of 12mm threaded steel bars, and the two ends of the hanger bars are equipped with hooks, which are hung and welded between the bottom bars and the transverse tie bars.

[0020] Furthermore, in the step 3, a tray may be embedded in the hanger bar or lateral reinforcement may be welded to increase the friction of the hanger bar in the filling body. One end of the hanger bar is fixed to the main reinforcement of the bottom reinforcement, and the other end of the hanger bar is fixed to the transverse tension bar. The connection needs to be welded, and the middle position of the hanger bar spacing in the route is appropriately increased.

[0021] According to calculation requirements, four hangers are arranged symmetrically for every 1.3m of laneway, with the middle hangers spaced 1.1m apart, the side hangers are 1.3m away from the middle hangers and 200mm away from the side walls. The hangers are 12mm diameter threaded steel bars, the hanger length is >2.0m, the row spacing should be ≤1.3m, and the hanger mesh is 1300×1500mm.

[0022] Furthermore, in the step 4, the artificial false roof adopts upper and lower layered filling bodies, the bearing layer thickness is 3.0m, and graded tailings are used for cementing filling, and its 28d strength reaches more than 5MPa, the connecting layer thickness is 1.0m, and all tailings are used for cementing filling;

[0023] The filling material is composed of tailings, cementitious materials and water. The mass concentration of the filling slurry is 62%~65%. The bearing layer is filled with graded tailings with a ash-sand ratio of 1:3. The filling height is 3.0m, and its 28d strength should reach above 5MPa. The connecting layer is filled with full tailings with a ash-sand ratio of 1:6. The filling height is 1.0m. After the construction is completed, a period of curing is required. Only after the strength requirements are met can construction work be carried out under the artificial false ceiling. The curing time must at least reach the final setting time of the filling body.

[0024] Furthermore, in the step 4, the bearing layer is filled with graded tailings with a ash-sand ratio of 1:3, and the top layer is filled with tailings to minimize the filling cost. The water seepage rate of the filling slurry should be ≤3%.

[0025] Furthermore, in the step 2, in the approach with a cross-sectional size of 4.5m×4.0m, a transverse reinforcement is laid every 1.3m, and a total of three longitudinal reinforcements are laid in the approach, with a longitudinal reinforcement in the center and a longitudinal reinforcement on both sides at intervals of 1.3m. The transverse reinforcement is at the bottom and the longitudinal reinforcement is at the top, and the bottom reinforcement mesh is 1300mm×1300mm; the intersection of the longitudinal and transverse reinforcements is tightened or welded with 24# iron wire.

[0026] Furthermore, in the step 2, the length of the horizontal and vertical steel bars is greater than 2.0m, the row spacing should be ≤1.3m, the diameter of the horizontal and vertical steel bars should be ≥12mm, and the spacing should be ≤1.3m. The diameter of the flexible mesh single wire is 2.5mm, the tensile strength of the single wire is 431MPa, the elongation of the single wire is 19%, and the mesh size is 50mm×50mm; when the access road is filled, the height of the steel mesh shall not be less than 100mm.

[0027] 3. Beneficial effects

[0028] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0029] The invention has a simple structure, convenient construction, reliable performance, good safety performance, good effect, and wide practicability. It provides a method for constructing an artificial false roof for a downward approach, which can be used in mining environments such as ore body surrounding rock fragmentation, development of joints and fissures, and poor stability, and realizes safe and efficient mining of the ore body, and has the advantages of small engineering volume, small amount of steel and cement, low construction cost, high safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a cross-sectional view along the approach direction of the present invention;

[0031] Figure 2 is a cross-sectional view of the false top section of the present invention;

[0032] Figure 3It is a top view of the false roof of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0034] Example 1

[0035] from Figure 1-3 It can be seen that the steps of a method for constructing an artificial false ceiling for a downward approach in this embodiment are as follows:

[0036] Step 1: Smooth the approach:

[0037] After the false roof approach is excavated, the floating stones remaining on both sides are crushed, the waste rocks and water in the approach need to be handled, and the bottom of the approach needs to be cleared and leveled; the dimensions of the excavation approach are: width 4.0~5.0m, height 4.0m, and the approach shape is rectangular;

[0038] Step 2: Laying of bottom reinforcement:

[0039] The bottom reinforcement adopts a double-layer steel mesh arrangement of transverse and longitudinal reinforcement plus mesh, and the mesh adopts a flexible mesh;

[0040] In step two, the bottom reinforcement is arranged with a double-layer steel mesh, that is, transverse and longitudinal reinforcement plus mesh. The transverse and longitudinal reinforcements are made of 12mm threaded steel bars. The bottom reinforcement must not be less than 100mm away from the bottom plate. The mesh is laid on the transverse and longitudinal reinforcements. The flexible mesh uses a 2.2mm diameter flexible mesh wire with a mesh size of 50mm×50mm. The mesh uses galvanized chain link fence, and the length of a single mesh is 5100mm×1600mm.

[0041] In the approach with a cross-sectional size of 4.5m×4.0m, a transverse reinforcement is laid every 1.3m. A total of three longitudinal reinforcements are laid in the approach, with one longitudinal reinforcement in the center and two longitudinal reinforcements on both sides at intervals of 1.3m. The transverse reinforcement is at the bottom and the longitudinal reinforcement is at the top, and the bottom reinforcement mesh is 1300mm×1300mm. The intersection of the longitudinal and transverse reinforcements is tightened or welded with 24# iron wire.

[0042] The length of the horizontal and vertical steel bars is >2.0m, and the row spacing should be ≤1.3m. The diameter of the horizontal and vertical steel bars should be ≥12mm, and the spacing should be ≤1.3m. The diameter of the flexible mesh single wire is 2.5mm, the tensile strength of the single wire is 431MPa, the elongation of the single wire is 19%, and the mesh size is 50mm×50mm; when filling the access road, the height of the steel mesh shall not be less than 100mm.

[0043] Step 3: Construction of hanging bars:

[0044] Horizontal tie bars are arranged at a height of 1.8m above the two sides of the tunnel, and the hanger bars are welded between the bottom reinforcement and the horizontal tie bars. The spacing between the hanger bars in the middle of the approach is appropriately increased;

[0045] In step three, holes are drilled at a height of 1.8m on both sides of the tunnel, with a hole depth greater than 300mm. Both ends of the transverse tie bars are embedded in the drilled holes at both ends to fix the hanger bars. After the side holes are drilled, the transverse tie bars should be embedded in the side walls to a depth of ≥300mm to ensure safe fixation. The transverse tie bars are made of 12mm threaded steel bars, and both ends of the hanger bars are equipped with hooks, which are hung and welded between the bottom bars and the transverse tie bars.

[0046] Trays can be embedded or lateral reinforcement can be welded on the hanger bar to increase the friction of the hanger bar in the filling body. One end of the hanger bar is fixed on the main reinforcement of the bottom reinforcement, and the other end of the hanger bar is fixed on the transverse tension bar. The connection needs to be welded, and the distance between the hangers in the route should be appropriately increased in the middle.

[0047] According to calculation requirements, four hangers are arranged symmetrically for every 1.3m of laneway, with the middle hangers spaced 1.1m apart, the side hangers are 1.3m away from the middle hangers and 200mm away from the side walls. The hangers are 12mm diameter threaded steel bars, the hanger length is >2.0m, the row spacing should be ≤1.3m, and the hanger mesh is 1300×1500mm.

[0048] Step 4: Bonding filling, building artificial retaining walls, and pouring the filling body after the artificial retaining walls meet the construction standards:

[0049] An artificial false roof construction method is adopted in which the key layer is filled with graded tailings with high ash-sand ratio cementation and the top is filled with full tailings with low ash-sand ratio cementation.

[0050] In step 4, the artificial false roof adopts upper and lower layered filling bodies, the bearing layer thickness is 3.0m, and graded tailings are used for cementing filling, and its 28d strength reaches more than 5MPa. The thickness of the connecting layer is 1.0m, and all tailings are used for cementing filling;

[0051] The filling material is composed of tailings, cementitious materials and water. The mass concentration of the filling slurry is 62%~65%. The bearing layer is filled with graded tailings with a cementitious filling ratio of 1:3. The filling height is 3.0m, and its 28d strength should reach more than 5MPa.

[0052] The top layer is filled with full tailings cemented with a lime-sand ratio of 1:6, and the filling height is 1.0m. After the construction is completed, a period of curing is required. Only after the strength requirements are met can construction work be carried out under the artificial false ceiling. The curing time must at least reach the final setting time of the filling body.

[0053] The bearing layer is filled with graded tailings with a ash-sand ratio of 1:3, and the top layer is filled with tailings to minimize the filling cost. The water seepage rate of the filling slurry should be ≤3%.

[0054] The invention has a simple structure, convenient construction, reliable performance, good safety performance, good effect, and wide practicability. It provides a method for constructing an artificial false roof for a downward approach, which can be used in mining environments such as ore body surrounding rock fragmentation, development of joints and fissures, and poor stability, and realizes safe and efficient mining of the ore body, and has the advantages of small engineering volume, small amount of steel and cement, low construction cost, high safety and reliability.

[0055] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A method for constructing an artificial false roof for a downward approach, characterized in that: The steps are: Step 1: Smooth the approach: After the false roof access road is excavated, the floating stones remaining on both sides are crushed, the waste rocks and accumulated water in the access road need to be handled, and the bottom of the access road needs to be cleared and leveled; Step 2: Laying of bottom reinforcement: The bottom reinforcement adopts a double-layer steel mesh arrangement of transverse and longitudinal reinforcement plus mesh, and the mesh adopts a flexible mesh; Step 3: Construction of hanging bars: Horizontal tie bars are arranged at a height of 1.8m above the two sides of the tunnel, and the hanger bars are welded between the bottom reinforcement and the horizontal tie bars. The spacing between the hanger bars in the middle of the approach is appropriately increased; Step 4: Bonding filling, building artificial retaining walls, and pouring the filling body after the artificial retaining walls meet the construction standards: An artificial false roof construction method is adopted in which the key layer is filled with graded tailings with high ash-sand ratio cementation and the top is filled with full tailings with low ash-sand ratio cementation.

2. A method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: The dimensions of the excavation route in step 1 are: width 4.0~5.0m, height 4.0m, and the route shape is rectangular.

3. The method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: In the step 2, the bottom reinforcement is arranged with a double-layer steel mesh, that is, transverse and longitudinal reinforcements plus mesh, the transverse and longitudinal reinforcements are made of 12mm threaded steel, the bottom reinforcement must not be less than 100mm away from the bottom plate, the mesh is laid on the transverse and longitudinal reinforcements, the flexible mesh uses a 2.2mm diameter flexible mesh wire, the mesh size is 50mm×50mm, the mesh uses galvanized chain link fence, and the length of a single mesh is 5100mm×1600mm.

4. The method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: In the step three, holes are drilled at a height of 1.8m on both sides of the tunnel, and the hole depth is greater than 300mm. The two ends of the transverse tie bars are embedded in the drilled holes at both ends to fix the hanger bars. The transverse tie bars are made of 12mm threaded steel bars, and the two ends of the hanger bars are equipped with hooks, which are hung and welded between the bottom bars and the transverse tie bars.

5. The method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: In the step 3, a tray can be embedded on the hanger bar or lateral steel bars can be welded to increase the friction of the hanger bar in the filling body. One end of the hanger bar is fixed on the main reinforcement of the bottom reinforcement, and the other end of the hanger bar is fixed on the transverse tension bar. The connection needs to be welded, and the middle position of the hanger bar spacing in the route is appropriately increased. According to calculation requirements, four hangers are arranged symmetrically for every 1.3m of laneway, with the middle hangers spaced 1.1m apart, the side hangers are 1.3m away from the middle hangers and 200mm away from the side walls. The hangers are 12mm diameter threaded steel bars, the hanger length is >2.0m, the row spacing should be ≤1.3m, and the hanger mesh is 1300×1500mm.

6. The method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: In the step 4, the artificial false roof adopts upper and lower layered filling bodies, the bearing layer thickness is 3.0m, and graded tailings are used for cementing filling, and its 28d strength reaches more than 5MPa, the connecting layer thickness is 1.0m, and all tailings are used for cementing filling; The filling material is composed of tailings, cementitious materials and water. The mass concentration of the filling slurry is 62%~65%. The bearing layer is filled with graded tailings with a ash-sand ratio of 1:

3. The filling height is 3.0m, and its 28d strength should reach above 5MPa. The connecting layer is filled with full tailings with a ash-sand ratio of 1:

6. The filling height is 1.0m. After the construction is completed, a period of curing is required. Only after the strength requirements are met can construction work be carried out under the artificial false ceiling. The curing time must at least reach the final setting time of the filling body.

7. The method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: In the step 4, the bearing layer is filled with graded tailings with a ash-sand ratio of 1:3, and the top layer is filled with tailings to minimize the filling cost. The water seepage rate of the filling slurry should be ≤3%.

8. The method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: In the step 2, in the approach with a cross-sectional size of 4.5m×4.0m, a transverse reinforcement is laid every 1.3m, and a total of three longitudinal reinforcements are laid in the approach, with a longitudinal reinforcement in the center and a longitudinal reinforcement on both sides at intervals of 1.3m. The transverse reinforcement is at the bottom and the longitudinal reinforcement is at the top, and the bottom reinforcement mesh is 1300mm×1300mm; the intersection of the longitudinal and transverse reinforcements is tightened or welded with 24# iron wire.

9. The method for constructing an artificial false ceiling for a downward approach according to claim 1, characterized in that: In the above step 2, the length of the horizontal and vertical steel bars is greater than 2.0m, the row spacing should be ≤1.3m, the diameter of the horizontal and vertical steel bars should be ≥12mm, and the spacing should be ≤1.3m. The diameter of the flexible mesh single wire is 2.5mm, the tensile strength of the single wire is 431MPa, the elongation of the single wire is 19%, and the mesh size is 50mm×50mm; when filling the access road, the height of the steel mesh shall not be less than 100mm.

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