A method for constructing wind bridge in underground coal mine

Abstract

The invention discloses a method for constructing an underground wind bridge in a coal mine, and relates to the technical field of underground wind bridge construction technology in a coal mine, and comprises the following steps: a, sweeping the bottom of the return air tunnel, and filling the swept bottom with the gangue from the top; b, digging along the top of the coal outlet horizontal river, gradually digging downward and connecting with the coal outlet horizontal river, and continuing to dig forward along the coal seam bottom plate; c, driving a locking anchor cable at the top of the coal tunnel in the coal outlet horizontal river; d, top-lifting construction; e, wind bridge material stone masonry wall construction; f, laying I-beams and pouring the wind bridge; g, setting the slope section of the wind bridge, and completing the underground wind bridge. The construction method provided by the invention reduces the need to lift the rock top to only about 1.5 meters through the improvement of the construction method, greatly reducing the amount of work for lifting the rock top and alleviating the labor intensity of the employees. In addition, the amount of gangue from the top of the rock is small and can be used as a wind bridge slope, without the need to be transported out of the well, thus avoiding the mixing of gangue and raw coal after the top is picked, indirectly improving the coal quality and effectively shortening the wind bridge construction time.

Description

Technical Field

[0001] The invention relates to the field of coal mining, in particular to the field of underground wind bridges in coal mines, and specifically to a method for constructing underground wind bridges in coal mines. Background Art

[0002] In the existing coal mine, the 2# coal seam pan area tunnel is arranged as three tunnels, excavated along the coal seam roof, with a designed tunnel height of 2.7m, double-wing mining, coal seam thickness of 3.85~6.05m, average thickness of 4.66m, belonging to thick coal seam mining, working face drift tunnel excavated along the coal seam floor, comprehensive mining top coal caving technology. Figure 2 As shown in the figure, during the mining process, there are situations where wind bridges are constructed at the intersection of the air intake chute and the return air lane in the panel area, or at the intersection of the return air chute and the transport lane or rail lane in the panel area. Each mining face is faced with the construction of 1~2 wind bridges. During the on-site mining process, the traditional original construction method of the wind bridge in the three-lane arrangement of the panel area lane is: (1) The return air lane is connected with the transverse lane, and both lanes are excavated along the roof of the coal seam. After the entire ventilation system is formed, the wind bridge construction begins; (2) The intersection of the transverse lane and the return air lane is the wind bridge section, and then blasting and top lifting and masonry are carried out in the wind bridge section to form a wind bridge.

[0003] There are many disadvantages in the traditional wind bridge construction method. For example, during the construction process, the rock top needs to be lifted about 2.7 meters, which requires a large amount of work, a long construction period, and high labor intensity for the workers. Then the wind bridge is built. During the construction of the wind bridge, a large amount of gangue is generated during the blasting and lifting process. Except for some gangue that can be used when making the wind bridge slope, most of the remaining gangue needs to be transported to the well, resulting in the gangue being mixed with the raw coal after the lifting, affecting the coal quality. In order to avoid the mixing of gangue and raw coal, the workload of transporting gangue by separate mine cars will be increased. In order to solve the above problems, it is necessary to improve the construction method of wind bridges in coal mines. Summary of the invention

[0004] The invention provides a method for constructing a wind bridge in an underground coal mine in order to solve the problems of large roof construction workload, long construction period, high labor intensity for workers, and generation of a large amount of gangue in the current traditional wind bridge construction method.

[0005] The present invention is implemented by the following technologies:

[0006] A method for constructing an underground wind bridge in a coal mine designed by the present invention comprises the following steps:

[0007] a. Accurately and strictly control the measuring distance. At 15m away from the two sides of the coal outlet in the return air roadway, that is, about 15m away from the designed penetration point, increase the coal cutting height, use the unit or manual pneumatic pick to support the excavation to sweep the bottom, and sweep the coal bottom at the slope where the wind bridge is required to be built to the solid bottom. The sweeping bottom specifications are 15m long, 4.7m wide, and 1.2m thick. The side of the sweeping bottom area does not need to be supported. The sweeping bottom is filled with the top-lifted gangue. The gangue can fall to the bottom of both sides of the return air roadway and does not need to be transported out of the mine, achieving the purpose of not leaving the mine with the top-lifted gangue;

[0008] b. The coal-exiting horizontal channel is excavated along the top to a distance of 10m from the return air roadway, and then gradually excavated forward along the coal seam floor to connect with the return air roadway, and then continued to excavate forward along the coal seam floor to form a ventilation system, so that it has the conditions for constructing a wind bridge;

[0009] c. Two locking anchor cables are installed at the top of the coal roadway at the coal outlet, 500mm away from both sides of the return air roadway. The two locking anchor cables on the same side are arranged symmetrically with respect to the center line of the return air roadway, with a spacing of 2400mm. The pre-tightening force of the locking anchor cables shall not be less than 140KN.

[0010] d. From the tail of the return airway, the wind bridge is constructed along the downwind direction. The two ends of the top are 5.25m away from the center line of the return airway. The blasting in the wind bridge top process is carried out by drilling and blasting or manual use of pneumatic picks to support and dig; the temporary support is set up by advanced anchor rods; the permanent support is supported by anchors, nets, belts, anchor cables, and shotcrete at the top of the section after the top is lifted; the wind bridge is inclined at 6.64m on both sides of the center line of the coal outlet. After completion, the inclined lengths of both sides are 2.427m, the top length is 5.942m, the height is 2.72m, the total horizontal length is 10.50m, the top height of the wind bridge is 1.5m, the slope top is 1m, the vertical height rises 0.62m, and the width is 4.7m; after the wind bridge is topped, the top of the wind bridge is 5.73m away from the bottom plate of the tunnel and 4.7m wide. After the distance is accurately and strictly controlled, the height of the top of the rock is reduced, which directly reduces the amount of work on the top of the rock and reduces the labor intensity of the employees;

[0011] e. Construction of wind bridge stone masonry wall: the two sides are cut with a depth of 300mm, and stone masonry wall support is used. The thickness of the stone wall is 500mm and the height is 2700mm. The foundation of the stone wall is set on the solid bottom, and mortar is laid on the foundation. The thickness of the mortar is based on the stable and flat stone. The stone wall surface should be firmly bonded, and the inner wall of the stone wall should be aligned with the lane side.

[0012] f. I-beam laying and pouring of wind bridge: I-beams are laid on the wind bridge wall. I-beams are 12# mining I-beams with a construction spacing of 600mm. The length of each end of the I-beam on the wall is not less than 500mm. A layer of net is laid on the I-beam, and concrete backboards are densely laid on the top of the laying net. The concrete backboard is 1200mm long, 200mm wide and 50mm thick. After the wind bridge is laid, C20 concrete is poured to form a concrete layer with a thickness of 300mm. After the wind bridge is constructed, ensure that the I-beam is 2.72m upward after concrete is poured and 2.7m below the I-beam;

[0013] g. Setting of the slope section of the wind bridge: fill the gangue from the top into the slope section. It is required to fill the gangue to ensure the flatness of the slope surface with a slope of 20°. The gangue from the top is fully utilized to serve as the slope of the wind bridge. During the entire construction process, the amount of gangue from the top is small, and there is no need to transport the gangue from the top of the bridge out of the well, thus realizing the green construction of the underground wind bridge. This avoids the mixing of gangue and raw coal after the top is picked, indirectly improving the coal quality, and pouring cement to prevent air leakage. Then, the formwork is used to cast the steps on the slope side of the wind bridge. Each step is 800mm long, 320mm wide and 150mm high, completing the underground wind bridge.

[0014] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a method for constructing an underground wind bridge in a coal mine, which reduces the need to lift the rock top of about 2.7 meters according to the traditional method to only about 1.5 meters through the improvement of the construction method, greatly reducing the amount of work to lift the rock top and alleviating the labor intensity of the employees. According to the traditional method, the amount of gangue after lifting the top of the wind bridge is large and the gangue needs to be transported out. With this wind bridge construction method, the amount of gangue after lifting the top of the rock is small, and the gangue can fall to the bottom of both sides of the return air channel and be used as the slope of the wind bridge. The gangue lifted from the top of the wind bridge does not need to be transported out of the mine, realizing the green construction of the underground wind bridge and achieving the purpose of not leaving the mine after lifting the top of the gangue. It avoids the mixing of gangue and raw coal after lifting the top, which indirectly improves the coal quality. The wind bridge construction time is shortened, which is conducive to the connection arrangement of the production team. Taking the coal-exporting Hengchuan of Lane 22051 as an example, according to calculations, it takes about 20 days to construct a wind bridge according to the traditional method, and about 15 days to construct a wind bridge after taking measures, saving about 5 days. The construction process is simple, which can effectively reduce the labor intensity of employees and the amount of waste rock transportation, and is suitable for wide promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The cross-section construction drawing of the wind bridge of the present invention is shown.

[0016] Figure 2 Represents the lane layout diagram.

[0017] Figure 3 A cross-sectional view of Meihengchuan is shown.

[0018] Figure 4 A cross-sectional view of the wind bridge of the present invention is shown.

[0019] Figure 5 A tunnel layout diagram of an embodiment of the present invention is shown.

[0020] In the figure: 1-return air tunnel, 2-coal outlet channel, 3-locking anchor cable, 4-stone wall, 5-I-beam, 6-concrete backboard, 7-concrete layer. DETAILED DESCRIPTION

[0021] The specific embodiments of the present invention are described below in conjunction with the accompanying drawings.

[0022] A method for constructing an underground wind bridge in a coal mine comprises the following steps:

[0023] a, such as Figure 1 , 4 As shown in 5, the measuring distance is accurately and strictly controlled. At 15m away from the two sides of the coal outlet 2 in the return air tunnel 1, that is, about 15m away from the designed penetration point, the coal cutting height is increased, and the bottom is swept by the unit or manual pneumatic pick to sweep the bottom. The coal bottom at the slope where the wind bridge is required is swept to the solid bottom. The sweeping bottom specifications are 15m long, 4.7m wide, and 1.2m thick. The side of the sweeping bottom area does not need to be supported. The sweeping bottom is filled with the top-lifted gangue. The gangue can fall to the bottom of both sides of the return air tunnel and does not need to be transported out of the mine. The green construction of the underground wind bridge is realized, and the purpose of not leaving the mine with the top-lifted gangue is achieved.

[0024] b. Coal outlet Hengchuan 2 is excavated along the top to 10m away from the return air tunnel 1, and then gradually excavated forward along the coal seam floor to connect with the return air tunnel 1, and continued to excavate forward along the coal seam floor to make it possible to construct the wind bridge. By accurately and strictly controlling the distance, the height of the rock top is reduced, which directly reduces the amount of work on the rock top and reduces the labor intensity of the employees;

[0025] c. Two locking anchor cables 3 are installed at the top of coal roadway 2 of coal outlet Hengchuan at a distance of 500mm from both sides of return air roadway 1. The two locking anchor cables 3 on the same side are arranged symmetrically with respect to the center line of return air roadway 1, with a spacing of 2400mm. The locking anchor cables 3 are Φ17.8mm×7.3m anchor cables, and one MSK2335 anchor and two MSZ2360 anchors are used together. A steel plate with a length of 300mm, a width of 300mm, and a thickness of 16mm is used as an anchor cable tray. The preload force of the locking anchor cables 3 is not less than 140KN.

[0026] d. From the tail of the return air tunnel 1, the top is constructed along the downwind direction. The two ends of the top are 5.25m away from the center line of the return air tunnel 1. The process flow of the wind bridge top is: safety inspection → drilling, charging, connecting → blasting → knocking the top → temporary support → permanent support → civilized production at the construction site; among them, hand-held air drill or YT-28 wet drilling is used for drilling, the hole depth is 1.2m, the charging amount is 400g / hole, and the third-level emulsion explosives and millisecond delay electric detonators permitted in coal mines are used. The wires are connected in series, and the FD200D (B) capacitor detonator is used for detonation. All the charges are detonated at one time; 2~3 water cannon muds are used for blasting, the sealing length is not less than 0.5m, and the minimum resistance is 1.2m. The line is not less than 0.3m; blasting is carried out by drilling and blasting or manual use of pneumatic picks for digging; temporary support is erected by advanced anchor rods; permanent support is carried out by anchor, net, belt, anchor cable, and shotcrete combined support at the top of the section after the top is raised; 6.64m on both sides of the center line of the coal-out Hengchuan 2 are the inclined slope sections of the wind bridge. After the wind bridge is formed, the inclined length of both sides is 2.427m, the top length is 5.942m, the height is 2.72m, the total horizontal length is 10.50m, the top height of the wind bridge is 1.5m, the slope top is 1m, the vertical height rises 0.62m, and the width is 4.7m; after the wind bridge is raised, the top of the wind bridge is 5.73m away from the bottom plate of the tunnel and 4.7m wide;

[0027] e. Construction of wind bridge stone masonry wall: the two sides are cut 300mm deep, and stone masonry wall support is used. The wall thickness of stone wall 4 is 500mm and the height is 2700mm. The foundation of stone wall 4 is set on the solid bottom, and mortar is laid on the foundation. The mortar uses 42.5 ordinary silicate cement, medium sand and M10 masonry mortar, and the weight ratio is cement: water: sand: crushed stone = 1: 0.47: 1.59: 3.39. The thickness of the mortar is based on the stable and flat stone. The wall surface of stone wall 4 should be firmly bonded, and the inner wall of stone wall 4 should be flush with the side of the lane;

[0028] f. I-beam laying and pouring of wind bridge: Figure 3 As shown, an I-beam 5 is placed on the wind bridge wall. The I-beam 5 is a 12# mining I-beam. The length of the first I-beam is 8.8m. A single-double beam arrangement is adopted with a spacing of 600mm. The length of each end of the I-beam 5 placed on the wall is not less than 500mm. A layer of net is laid on the I-beam 5. A concrete back plate 6 is densely laid above the laid net. The concrete back plate 6 is 1200mm long, 200mm wide and 50mm thick. After the wind bridge is laid, C20 concrete is poured to form a concrete layer 7. The thickness of the concrete layer 7 is 300mm. After the wind bridge is constructed, it is ensured that the I-beam is 2.72m upward after the concrete is poured and 2.7m below the I-beam.

[0029] g. Setting of the wind bridge slope section: Fill the gangue from the top into the slope section, and fill it flat to ensure the slope surface is flat, with a slope of 20°. The gangue from the top is fully utilized as the wind bridge slope. During the entire construction process, the amount of gangue from the top is small, and there is no need to transport the gangue from the top of the bridge out of the well, thus realizing the green construction of the underground wind bridge, thus avoiding the mixing of gangue and raw coal after the top is picked, and indirectly improving the coal quality. Cement is poured to prevent air leakage, and then the steps are poured on the slope side of the wind bridge using a template. Each step is 800mm long, 320mm wide, and 150mm high to complete the underground wind bridge.

[0030] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for constructing an underground wind bridge in a coal mine, characterized in that: The steps include: a. At the return airway (1), 15 m away from the coal outlet (2) on both sides, the bottom of the sweeping is carried out. The specifications of the sweeping are 15 m long, 4.7 m wide and 1.2 m thick. The sweeping area is filled with the top-carrying waste rock; b. The coal-exiting horizontal channel (2) is excavated along the top to a distance of 10 m from the return air tunnel (1), and then gradually excavated downward along the coal seam floor to connect with the return air tunnel (1), and then continued to excavate forward along the coal seam floor; c. Two locking anchor cables (3) are installed at the top of the coal roadway of the coal outlet (2) at a distance of 500 mm from both sides of the return air roadway (1). The two locking anchor cables (3) on the same side are arranged symmetrically with respect to the center line of the return air roadway (1) with a spacing of 2400 mm; d. From the tail of the return airway (1), the wind bridge is constructed along the downwind direction. The two ends of the top are 5.25m away from the center line of the return airway (1). The wind bridge is 6.64m on both sides of the center line of the coal outlet cross river (2). After the wind bridge is formed, the inclined lengths of both sides are 2.427m, the top length is 5.942m, the height is 2.72m, and the total horizontal length is 10.50m. The top height of the wind bridge is 1.5m, the slope top is 1m, the vertical height rises 0.62m, and the width is 4.7m. After the wind bridge is topped, the top of the wind bridge is 5.73m away from the bottom plate of the roadway and 4.7m wide. e. Construction of wind bridge stone masonry wall: the two sides are cut with a depth of 300mm, and stone masonry wall support is used. The stone wall (4) has a wall thickness of 500mm and a height of 2700mm. The foundation of the stone wall (4) is set on a solid bottom, and mortar is laid on the foundation. The inner wall of the stone wall (4) is flush with the side of the lane; f. I-beam laying and pouring of the wind bridge: I-beams (5) are laid on the wind bridge wall with a spacing of 600 mm, a layer of net is laid on the I-beams (5), and concrete backing plates (6) are densely laid above the laid net. The concrete backing plates (6) are 1200 mm long, 200 mm wide and 50 mm thick. Concrete is poured to form a concrete layer (7). The thickness of the concrete layer (7) is 300 mm. After the wind bridge is constructed, it is ensured that the I-beams are 2.72 m upward after the concrete is poured and 2.7 m below the I-beams; g. Setting of the wind bridge slope section: fill the top gangue into the slope section with a slope of 20°. After pouring the cement, use the formwork to cast steps on the slope side of the wind bridge. Each step is 800mm long, 320mm wide and 150mm high to complete the underground wind bridge.

2. A method for constructing an underground wind bridge in a coal mine according to claim 1, characterized in that: In step d, the blasting in the wind bridge topping process is carried out by drilling and blasting or manually using a pneumatic pick to support the excavation; temporary support is erected by advanced anchor rods; permanent support is provided at the top of the section after topping by a combination of anchors, nets, belts, anchor cables and shotcrete.

3. A method for constructing an underground wind bridge in a coal mine according to claim 1, characterized in that: In step c, the locking anchor cable (3) is a Φ17.8 mm×7.3 m anchor cable, and is used in conjunction with one MSK2335 anchor and two MSZ2360 anchors, and a steel plate of 300 mm in length, 300 mm in width and 16 mm in thickness as an anchor cable tray.

4. A method for constructing an underground wind bridge in a coal mine according to claim 1, characterized in that: In step e, the mortar uses No. 42.5 ordinary Portland cement, medium sand and M10 masonry mortar, and the weight ratio is cement: water: sand: crushed stone = 1: 0.47: 1.59: 3.

39.

5. A method for constructing an underground wind bridge in a coal mine according to claim 1, characterized in that: In step a, the bottom is swept by using a machine group or manually using a pneumatic pick to dig.

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