Construction method for repairing shaft of coal mine air return vertical shaft

Abstract

The invention discloses a construction method for repairing a shaft of a coal mine return air vertical shaft, which comprises the following steps of: removing an anti-explosion cover according to the opportunity of reverse air drilling, cutting and lifting a required hole in the anti-explosion cover by using a plasma cutting machine, and then installing a lifting system; the multilayer construction hanging scaffold in the shaft and the fixing disc in the shaft are integrally hoisted, the fixing disc in the shaft is fixed to the shaft wall, the multilayer construction hanging scaffold in the shaft is fixed to the shaft wall in a layered mode, an anti-explosion cover is installed, and a steel wire rope is lifted to be reliably connected with the multilayer construction hanging scaffold in the shaft; a plurality of layers of construction hanging scaffolds in a shaft are utilized, a pre-stressed anchor net shotcrete supporting technology is adopted for conducting layered reinforcement on the damaged and caving area of the shaft wall, and wall back grouting treatment is conducted on concentrated outlet points. The method is suitable for repairing construction of damaged areas such as shaft water leakage and shaft wall falling of the coal mine air return vertical shaft, construction is safe and efficient, equipment connection is stable, the repairing quality is high, and the construction period occupied by shaft repairing is short.

Description

Technical Field

[0001] The invention belongs to the technical field of mining engineering, and in particular relates to a coal mine return air shaft repair construction method. Background Art

[0002] In coal mining, the shaft, a critical connection between the surface and underground working areas, is crucial for its safety and stability. The structural integrity of the shaft not only impacts the proper functioning of coal transportation and ventilation systems but also directly affects the lives of miners. However, due to long-term geological and hydrological erosion, geostress, and the aging of shaft support structures, shaft walls often become loose, leak, and become unanchored. This is especially true in vertical return shafts, where shaft wall damage can lead to serious consequences such as gas leaks, equipment damage, and even casualties.

[0003] Traditional wellbore repair methods primarily focus on simple repairs to damaged areas, such as localized grouting and replacement of damaged support structures. While these methods can alleviate the problem to a certain extent, they often fail to fundamentally address the overall stability of the wellbore. For example, in areas where the wellbore has become loose and detached, localized grouting alone may not effectively prevent further damage. For anchor bolts that have become dislodged, traditional methods may not ensure a secure bond between the repaired anchor and the wellbore. Summary of the Invention

[0004] The purpose of the present invention is to provide a coal mine return air shaft repair construction method, which has safe and efficient construction, stable equipment connection and high repair quality.

[0005] To achieve the above object, the present invention provides a coal mine return air shaft repair construction method, comprising the following steps:

[0006] Step 1: Prepare the site, accurately determine the coordinates of the temporary derrick foundation and winch foundation, and cast the temporary derrick and winch foundation in advance;

[0007] Step 2: Hoist the temporary derrick in sections, monitor verticality throughout the process, and perform laser calibration after installing the sheave on the temporary derrick to ensure that the sheave is aligned with the wellbore centerline;

[0008] Step 3: Take advantage of the backwind drill to remove the explosion-proof cover and use a plasma cutter to cut the holes required for lifting. Then install the lifting system, which includes a spare safety stabilizer, a lifting winch, and a wire rope.

[0009] Step 4: hoist the multi-layer construction hoisting platform and the fixed plate in the wellbore as a whole, and fix the fixed plate in the wellbore to the wellbore wall. The multi-layer construction hoisting platform in the wellbore is fixed to the wellbore wall in layers, and the air and water pipes, cables, communication cables, and lighting are hung simultaneously;

[0010] Step 5: Install the explosion-proof cover and ensure that the lifting wire rope is reliably connected to the multi-layer construction hoisting platform in the wellbore;

[0011] Step 6: Using multi-layer construction hoists in the wellbore, adopt prestressed anchor mesh spraying support technology to reinforce the damaged and collapsed areas of the wellbore wall in layers, and perform back-wall grouting treatment on the concentrated exit points;

[0012] Step 7: After the well wall treatment is completed, firmly connect the multi-layer construction hoisting platform in the wellbore with the fixed plate in the wellbore, and remove the temporary well frame and lifting system;

[0013] Step 8. After removing the explosion-proof cover, use two cranes to completely dismantle the fixed plate and construction hoisting plate in the wellbore. Finally, install the explosion-proof cover and effectively seal the cut drill hole.

[0014] As a further solution of the present invention: when the mine depth is less than 200m, the temporary derrick adopts Type I derrick; when the mine depth is between 200 and 400m, the temporary derrick adopts Type II derrick; when the mine depth is between 400 and 600m, the temporary derrick adopts Type III derrick.

[0015] As a further solution of the present invention: the fixed plate in the wellbore is welded with a grid-shaped steel structure, and the fixed plate in the wellbore and the return air well wall are firmly connected with chemical anchor rods.

[0016] As a further solution of the present invention: the multi-layer construction hanging platform in the wellbore is a double-layer network steel structure, the upper layer is a protective layer, the lower layer is a working layer, and the height of each layer is 2 to 4 meters. The multi-layer construction hanging platform in the wellbore is installed in different directions with adjustable hydraulic cylinders to cooperate with the well wall to fix the multi-layer construction hanging platform inside.

[0017] As a further solution of the present invention: before the temporary derrick is installed, the explosion-proof cover is lifted to an open space by a crane, and then a lifting wire rope hole with a diameter of 50-80mm, two hanging plate rope holes with a diameter of 50-80mm, a hanging plate stabilizing rope hole with a diameter of 50-80mm, and a safety ladder rope hole with a diameter of 50-80mm are cut on the explosion-proof cover by a plasma cutting machine. At least two rope holes with a diameter of 5-15mm are added 200mm around the hanging plate rope hole, and oil-impregnated asbestos rope is laid in each rope hole.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In the wellbore repair construction, the present invention utilizes multi-layer construction hoisting platforms in the wellbore, adopts prestressed anchor net spraying support technology to reinforce the damaged and collapsed areas of the wellbore wall in layers, and performs back-wall grouting treatment on the concentrated exit points, thereby improving the flexibility and safety of construction.

[0020] At the same time, the construction process is carried out in sections from top to bottom, making full use of the space of the hanging platform to ensure that the construction quality of each section is qualified before proceeding to the next section, which effectively reduces construction risks and improves repair efficiency and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the construction structure of the present invention.

[0022] Figure 2 It is a plan view of a multi-layer construction hanging platform in a wellbore of the present invention.

[0023] Figure 3 It is a plan view of the position of the rope hole of the explosion-proof cover of the present invention.

[0024] Figure 4 This is a schematic diagram of the Type I derrick structure of the present invention.

[0025] Figure 5 It is a schematic diagram of the structure of Type II derrick of the present invention.

[0026] Figure 6 It is a schematic diagram of the structure of Type III derrick of the present invention.

[0027] In the figure: 1. Temporary derrick, 2. Sky pulley, 3. Explosion-proof cover, 4. Fixed plate in the shaft, 5. Multi-layer construction hoisting plate in the shaft, 6. Protective layer, 7. Working layer, 8. Wire rope, 9. Artificial passage, 10. Hanging basket passage, 11. Adjustable hydraulic cylinder for each layer, 12. Gas pipeline, 13. Safety ladder entrance, 14. Ladder room entrance, 15. Rope hole for hoisting plate, 16. Rope hole for hoisting plate stabilizing rope, 17. Hole for lifting wire rope, 18. Rope hole for safety ladder, 19. Shaft wall, 20. Hoisting winch. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, a coal mine return air shaft repair construction method includes the following steps:

[0030] Step 1: Prepare the site, accurately determine the coordinates of the temporary derrick 1 foundation and the winch foundation, and cast the temporary derrick 1 and winch foundation 14-28 days in advance;

[0031] Step 2: Hoist the temporary derrick 1 in sections, monitor the verticality throughout the process, and perform laser calibration after installing the sheave 2 on the temporary derrick 1 to ensure that the sheave is aligned with the wellbore centerline;

[0032] Step 3: Take advantage of the backwind drill to remove the explosion-proof cover 3 and use a plasma cutter to cut the required holes for lifting on the explosion-proof cover 3. Then install the lifting system, which includes a spare safety stabilizer, a lifting winch 20, and a wire rope 8.

[0033] Step 4: hoist the multi-layer construction hoisting plate 5 and the fixed plate 4 in the wellbore as a whole, and fix the fixed plate 4 in the wellbore to the well wall 19. The multi-layer construction hoisting plate 5 in the wellbore is fixed to the well wall 19 in layers, and the wind and water pipes, cables, communication cables, and lighting are hung simultaneously;

[0034] Step 5: Install the explosion-proof cover 3 and ensure that the lifting wire rope 8 is reliably connected to the multi-layer construction hoisting platform 5 in the wellbore;

[0035] Step 6: Using the multi-layer construction hoisting platform 5 in the wellbore, adopt the prestressed anchor mesh spraying support technology to reinforce the damaged and collapsed areas of the wellbore 19 in layers, and perform back-wall grouting treatment on the concentrated exit points;

[0036] Step 7: After the treatment of the well wall 19 is completed, the multi-layer construction hoisting plate 5 in the wellbore is firmly connected to the fixed plate 4 in the wellbore, and the temporary well frame 1 and the lifting system are removed;

[0037] Step 8: After removing the explosion-proof cover 3, use two cranes to completely dismantle the fixed plate 4 and the construction hoisting plate in the wellbore, and finally install the explosion-proof cover 3 and effectively seal the cut drill hole.

[0038] Furthermore, the temporary derrick 1 is selected according to the depth of the mine. When the depth of the mine is less than 200m, a type I derrick is used, such as Figure 4 As shown; the mine depth is between 200 and 400m, and a type II headframe is used. Figure 5 As shown; the mine depth is between 400 and 600m, and a type III headframe is used. Figure 6 As shown in the figure, different derricks are selected for different mine depths mainly to improve the comprehensive adaptation of system requirements, structural safety and economy.

[0039] In order to meet the needs of return air in the return air shaft, further, the fixed plate 4 in the shaft is welded with a grid-like steel structure, and the fixed plate 4 in the shaft and the return air shaft wall 19 are firmly connected with chemical anchor rods, so that the reinforcement workers have better stability when working on the multi-layer construction hoisting plate 5 in the shaft;

[0040] like Figure 2 As shown, the multi-layer construction hanging platform 5 in the wellbore is a double-layer network steel structure, the upper layer is a protective layer 6 to prevent foreign objects from falling and causing harm to the workers during work, and the lower layer is a working layer 7. It is a special-shaped hanging platform, and the height of each layer is between 2 and 4 meters. To ensure the activity space of the staff, the first layer is used for cleaning the well wall 19, and the second layer is used for repairing the well wall 19. The double layer can work at the same time, saving working time, and the multi-layer construction hanging platform 5 in the wellbore is installed with adjustable hydraulic cylinders 11 in different directions to cooperate with the well wall 19 to fix the internal multi-layer construction hanging platform to prevent the multi-layer construction hanging platform 5 in the wellbore from shaking during work.

[0041] In order to prevent gas explosion, further, before the temporary derrick 1 is installed, the explosion-proof cover 3 is lifted to an open space by a crane, and then a plasma cutting machine is used to cut the explosion-proof cover 3, such as Figure 3 As shown, there is a hole for lifting wire rope 8 with a diameter of not less than 50mm, two holes 15 for hanging plate rope with a diameter of not less than 50mm, a hole 16 for hanging plate stabilizing rope with a diameter of not less than 50mm, and a hole 18 for safety ladder rope with a diameter of not less than 50mm. At least one rope hole with a diameter of not less than 5mm is added 200mm around the hanging plate rope hole 15. Each rope hole needs to be paved with oil-impregnated asbestos rope to ensure that the rope is in close contact with the contact surface in order to reduce the air leakage rate through the pores.

[0042] The hoisting winch 20 during the construction process is equipped with a light bucket and a spare safety stabilizing vehicle. As a spare hoisting winch 20, a soft ladder is provided to prevent other accidents from occurring in the wellbore and interrupting the hoisting, so that personnel can be evacuated in time.

[0043] The air and water pipes are equipped with self-provided screw air compressors. A high-pressure hose with a diameter of not less than 25 mm is used to supply air to the well. A high-pressure hose with a diameter of not less than 25 mm is also used to supply water to the well through a submersible pump in the ground water supply tank. Both high-pressure pipes use straight-through connectors and U-shaped card connections, and are fixed on the crossbeams of the safety ladder. During the repair period, an independent signal system is set up as a signal connection between the well and the ground. The communication cable should be fixed on the steel beam between the ladders and move up and down with the hoisting platform for easy movement. At the same time, a lighting cable with anti-short circuit and leakage protection functions is laid. Two waterproof and explosion-proof lighting lamps are installed on the protective layer 6 and the working layer 7 of the multi-layer construction hoisting platform 5 in the wellbore.

[0044] The present invention combines anchor-mesh spraying with multi-layer anchor-mesh spraying, with the core principle being "layered application and synergistic action": first, a thin layer of concrete (initial spraying, 50-70mm) is sprayed to promptly seal the rock surface; then, anchor rods (cables) are installed and steel mesh is laid to provide active reinforcement; finally, a secondary spraying (total thickness can reach over 100-200mm) is performed to wrap the anchor mesh to form an integral flexible load-bearing shell. This phased process allows the support structure to adapt to surrounding rock deformation in steps. By gradually reinforcing the multi-layer spraying layer and anchor mesh, the integrity, toughness, and deformation resistance of the support system are significantly improved, effectively controlling large deformations in complex projects such as deep roadways and weak tunnels. It is a reliable method widely verified in geotechnical engineering.

Claims

1. A coal mine return air shaft repair construction method, characterized in that: The following steps are involved: Step 1: Prepare the site, accurately determine the azimuth coordinates of the temporary derrick (1) foundation and the winch foundation, and cast the temporary derrick (1) and the winch foundation in advance; Step 2: hoist the temporary derrick (1) in sections, monitor the verticality throughout the process, install the sheave (2) on the temporary derrick (1), and then perform laser calibration to ensure that the sheave is aligned with the wellbore centerline; Step 3: Take advantage of the backwind drill to remove the explosion-proof cover (3) and use a plasma cutter to cut the holes required for lifting on the explosion-proof cover (3). Then install the lifting system, which includes a spare safety stabilizer, a lifting winch (20), and a wire rope (8); Step 4: hoist the multi-layer construction hoisting plate (5) and the fixed plate (4) in the wellbore as a whole, and fix the fixed plate (4) in the wellbore on the wellbore wall (19). The multi-layer construction hoisting plate (5) in the wellbore is fixed to the wellbore wall (19) in layers, and the wind and water pipes, cables, communication cables, and lighting are hung simultaneously; Step 5: Install the explosion-proof cover (3) and reliably connect the lifting wire rope (8) to the multi-layer construction hoisting platform (5) in the wellbore; Step 6: Using the multi-layer construction hoisting platform (5) in the wellbore, adopt the prestressed anchor mesh spraying support technology to reinforce the damaged and collapsed areas of the wellbore wall (19) in layers, and perform grouting treatment on the concentrated exit points; Step 7: After the treatment of the well wall (19) is completed, the multi-layer construction hoisting plate (5) in the wellbore is firmly connected to the fixed plate (4) in the wellbore, and the temporary well frame (1) and the lifting system are removed; Step 8: After removing the explosion-proof cover (3), use two cranes to completely dismantle the fixed plate (4) and the construction hoisting plate in the wellbore, and finally install the explosion-proof cover (3) and effectively seal the cut drill hole.

2. A coal mine return air shaft repair construction method according to claim 1, characterized in that: When the depth of the mine is less than 200m, the temporary derrick (1) adopts type I derrick; when the depth of the mine is between 200 and 400m, the temporary derrick (1) adopts type II derrick; when the depth of the mine is between 400 and 600m, the temporary derrick (1) adopts type III derrick.

3. A coal mine return air shaft repair construction method according to claim 1, characterized in that: The fixed plate (4) in the shaft is welded with a grid-shaped steel structure, and the fixed plate (4) in the shaft is firmly connected to the return air shaft wall (19) by using chemical anchor rods.

4. A coal mine return air shaft repair construction method according to claim 1, characterized in that: The multi-layer construction hoisting platform (5) in the wellbore is a double-layer network-shaped steel structure, the upper layer is a protective layer (6), the lower layer is a working layer (7), and the height of each layer is 2 to 4 meters. The multi-layer construction hoisting platform (5) in the wellbore is installed with adjustable hydraulic cylinders (11) in different directions to cooperate with the well wall (19) to fix the multi-layer construction hoisting platform inside.

5. A coal mine return air shaft repair construction method according to claim 1, characterized in that: Before the explosion-proof cover (3) is installed on the temporary derrick (1), the explosion-proof cover (3) is hoisted to an open space by a crane, and a hole for a lifting wire rope (8) with a diameter of 50-80 mm, two holes for a hoisting plate rope with a diameter of 50-80 mm, a hole for a hoisting plate stabilizing rope with a diameter of 50-80 mm, and a hole for a safety ladder rope with a diameter of 50-80 mm are cut on the explosion-proof cover (3) by a plasma cutting machine. At least two rope holes with a diameter of 5-15 mm are added 200 mm around the hoisting plate rope hole (15), and oil-soaked asbestos rope is laid in each rope hole.

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