Arrangement structure and prevention and control method for mining roadway of rock burst working face

Abstract

The invention relates to the technical field of coal seam mining, in particular to an arrangement structure and a control method of a mining roadway of a rock burst working face. According to the arrangement structure of the working face mining roadways, the two mining roadways are integrally arranged in a stable rock stratum below a coal seam, the working faces of the two mining roadways are divided into coal seam parts and inclined parts, and inclined angles exist between the inclined parts of the working faces and bottom plates of the mining roadways; the prevention and control method mainly comprises the following steps: firstly, arranging a mining roadway according to the structure, then performing bottom plate pressure relief on a rock burst working face, and finally, when mining operation is performed on the working face, bidirectionally cutting coal, pushing a conveyor and pulling a hydraulic support for a coal mining machine of a coal seam part of the working face; for the inclined part of the working face, the coal mining machine cuts coal unidirectionally. The method effectively solves the problems of poor roadway stability and difficulty in scour prevention in the recovery process of the rock burst coal seam, is beneficial to prevention and treatment of the rock burst of the working face, greatly improves the production efficiency, and improves the development of a coal mine.

Description

Technical Field

[0001] The invention relates to the technical field of coal seam mining, and in particular to an arrangement structure and a prevention and control method for a mining tunnel in a rock burst working face. Background Art

[0002] Rock burst, as one of the coal-rock dynamic hazards, is a special form of pressure manifestation in mines. Rock burst mainly occurs in mining tunnels, endangering the safety of personnel and damaging the normal operation of equipment. In current mine construction, mining tunnels are generally arranged in coal seams. Due to the high stress concentration in deep coal seams, rock burst is prone to occur. Mining tunnels arranged in coal seams require a large number of pre-pressure relief measures, which are labor-intensive and cause mining disorders. During the mining process, the tunnels are easily affected by mining and are prone to mine pressure manifestation. The safety is also poor, which seriously affects normal production.

[0003] Therefore, it is urgent to design a new layout structure of the mining tunnel to improve the stability of the mining tunnel and reduce the workload of maintenance and repair. At the same time, it is more conducive to the prevention and control of rock burst on the working face. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a practical, safe, fast, efficient and low-investment layout structure of a rock burst working face mining tunnel and a rock burst prevention and control method.

[0005] The technical solution of the present invention is: an arrangement structure of mining roadways for rock burst working face, comprising two mining roadways arranged in parallel, the two mining roadways are integrally located in a stable rock layer below the coal seam, and the working face is located between the two mining roadways;

[0006] The working face comprises a coal seam portion of the working face which is entirely located in the coal seam and an inclined working face portion which extends from both ends of the coal seam portion to the ends of the mining roadway and passes through the working face, and an adjustment angle exists between the inclined working face portion and the bottom plate of the mining roadway;

[0007] Furthermore, in order to ensure the stability of the hydraulic support on the working surface and control the length of the inclined portion of the working surface, the angle of the tilt adjustment is between 5° and 10°.

[0008] In addition, the present invention also provides a method for preventing and controlling rock burst working surface, comprising the following steps:

[0009] Step 1: In order to meet the needs of ventilation, pedestrians, transportation, etc. during coal mining operations at the working face, reduce the workload of tunnel maintenance, and ensure the stability of the tunnel surrounding rock, the two mining tunnels are arranged as a whole in the stable rock layer;

[0010] Step 2: Setting a working face located entirely in the coal seam between the two mining tunnels;

[0011] The working face comprises a coal seam portion of the working face which is entirely located in the coal seam and an inclined working face portion extending from both ends of the coal seam portion to the ends of the tunnel respectively, and the inclined working face portion has an adjustment angle with the bottom plate of the tunnel;

[0012] Step 3: Drill holes on the bottom plate of the working surface to relieve pressure;

[0013] Before the mining operation, the working face floor is weakened to change the physical properties of the floor and reduce the impact tendency index, so as to eliminate the impact risk. The treatment measures include hydraulic fracturing, deep hole pre-splitting blasting, etc. Pressure relief drilling holes are arranged on the side walls of the working faces of the two lanes to relieve the pressure on the stable rock formations of the working face floor;

[0014] Furthermore, to ensure the pressure relief effect, the drilling depth of the hydraulic fracturing scheme is 80m~90m, and the hole spacing is 10m~20m; the drilling depth of the deep hole pre-splitting blasting scheme is 80m~90m, the hole spacing is 5m~10m, and the charge of each blasting hole is 5kg~10kg;

[0015] Step 4: Carry out mining operations on the working face;

[0016] During the mining operation, the shearer in the coal seam of the working face cuts coal in both directions, pushes the conveyor, and pulls the hydraulic support. In the inclined part of the working face, the shearer cuts coal in one direction, that is, it does not cut coal when going up, but cuts coal when going down; when the shearer is not cutting coal when going up, it pushes the front conveyor from bottom to top along the upward direction of the shearer, pulls the hydraulic support, pushes the rear conveyor, and caving the top coal;

[0017] When the coal mining machine is going down to cut coal, it does not push the conveyor, pull the hydraulic support, or put the top coal;

[0018] Furthermore, when pulling the hydraulic support, the telescopic beam of the hydraulic support should be extended first, and the top plate with initial pressure and close to the inclined part of the working surface should be used to pull the hydraulic support;

[0019] Furthermore, when top coal is released at the inclined part of the working face, the hydraulic supports are pulled one by one from bottom to top along the upward direction of the coal mining machine.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention effectively solves the problem of poor tunnel stability during mining of coal seams with rock burst, reduces the maintenance cost of the mining tunnel, reduces the occurrence of rock burst in the mining tunnel, and is beneficial to the prevention and control of rock burst on the working face, greatly improves production efficiency, and promotes the development of coal mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a mining tunnel arrangement structure for a rock burst coal seam according to the present invention;

[0022] Figure 2 It is a schematic diagram of the arrangement of the pressure relief drilling holes in the bottom plate of the rock burst working face of the present invention;

[0023] In the figure: 1. Coal seam; 2. Stable rock layer; 3. Working face; 4. Mining tunnel; 5. Adjusting the inclination angle; 6. Coal seam part of the working face; 7. Inclined part of the working face; 8. Pressure relief drilling hole. DETAILED DESCRIPTION

[0024] The technical solution adopted by the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments of the specification.

[0025] like Figure 1 As shown, firstly, the present invention provides an arrangement structure of mining roadways for rock burst working face, comprising two mining roadways 4 arranged in parallel, wherein the two mining roadways 4 are integrally located in a stable rock layer 2 below a coal seam 1, and a working face 3 is located between the two mining roadways 4;

[0026] The working face 3 includes a working face coal seam portion 6 which is entirely located in the coal seam 1 and a working face inclined portion 7 which extends from both ends of the working face coal seam portion 6 to the ends of the mining tunnel 4 and passes through the working face inclined portion 7. The working face inclined portion 7 and the bottom plate of the mining tunnel 4 form an inclination angle 5.

[0027] Further, as a preferred technical solution, in this embodiment, the angle of the tilt adjustment angle 5 is between 5° and 10°, that is, the stability of the hydraulic support of the inclined part 7 of the working face during coal mining is ensured and the length of the inclined part 7 of the working face is controlled.

[0028] Specifically, the present invention arranges two parallel mining tunnels 4 as a whole in the stable rock layer 2 below the coal seam 1, and the working face 3 is located in the coal seam 1. The two mining tunnels 4 are rock tunnels with stronger surrounding rock stability. In order to make the mining tunnels 4 pass through the coal seam 1 of the working face 3, a certain range of inclination adjustment is performed to form an inclined working face portion 7 with a slope. In order to ensure the stability of the inclined working face portion 7, the inclination angle 5 is controlled between 5° and 10°.

[0029] In addition, taking a mining area in Shaanxi Province as an example, the mining area belongs to the Binchang mining area. The main mining coal seam has a strong impact tendency, and the rock layer at the bottom of the main mining coal seam has no impact tendency. If the mining tunnel is arranged in the coal seam during excavation, the tunnel roof will fall off severely, the entire tunnel cannot be formed, and support is difficult.

[0030] Therefore, in order to solve the above problems, the present invention also provides a method for preventing and controlling rock burst on a working face, comprising the following steps:

[0031] Step 1: In order to meet the needs of ventilation, pedestrians, transportation, etc. during the coal mining operation of the working face 3, reduce the workload of tunnel maintenance, and ensure the stability of the tunnel surrounding rock, the two mining tunnels 4 are arranged as a whole in the stable rock layer 2 below the coal seam 1;

[0032] In this embodiment, the specifications of the mining tunnel 4 are a rectangular tunnel with a width of 4.8m and a height of 3.3m.

[0033] Step 2: A working face 3 is arranged between two mining tunnels 4 and is located entirely in the coal seam 1;

[0034] The working face 3 includes a working face coal seam portion 6 which is entirely located in the coal seam 1 and a working face inclined portion 7 which extends from both ends of the working face coal seam portion 6 to the ends of the mining tunnel 4. There is an adjustment angle 5 between the working face inclined portion 7 and the bottom plate of the mining tunnel 4, so that there is an adjustment slope from the working face inclined portion 7 to the working face coal seam portion 6. In order to ensure the stability of the working face hydraulic support and control the length of the adjustment working face, the adjustment angle 5 is 5° to 10°.

[0035] In this embodiment, the inclined length of the working face 3 is 200m, and the strike length is 1602m. After the mining tunnel 4 is excavated in place, the working face 3 is excavated from the tunnel end position, specifically, firstly 20m is constructed at 10°; then 180m is constructed at a horizontal tunnel; and then 20m is constructed at -10° to a through tunnel. That is, the slope of the inclined part 7 of the working face is about 10°, and the length of the inclined part 7 of the working face is about 20m.

[0036] Step 3: Drill holes on the bottom plate of the working surface 3 to relieve pressure;

[0037] Before the mining operation is carried out on the working face 3, the bottom plate of the working face 3 needs to be depressurized, and the physical properties of the bottom plate of the rock burst working face 3 are changed to reduce its rock burst tendency index, thereby achieving the purpose of eliminating the rock burst risk; Figure 2 As shown, a pressure relief borehole 8 is drilled into the stable rock layer 2 at the side walls of the working faces 3 of the two mining tunnels 4, and hydraulic fracturing or deep hole pre-splitting blasting measures are used in the pressure relief borehole 8 to relieve pressure;

[0038] In this embodiment, two pressure relief solutions are provided, and one of the measures can be taken during the specific construction:

[0039] Hydraulic fracturing pressure relief scheme: Hydraulic fracturing technology refers to the technology of prefabricating cracks in the fracturing section of the borehole to control the direction of hydraulic fracturing crack expansion. The pressure relief borehole 8 is constructed ahead of the working face, and the pressure relief borehole 8 is arranged along the axial direction of the tunnel. The axial angle between the pressure relief borehole 8 and the recovery tunnel 4 is 90°. It is set in the direction of the working face 3. The drill bit diameter is 75mm, the borehole length is 90m, and the borehole spacing is 15m. The fracturing stops at 25m from the hole mouth, and each hole is fractured 28 times. The working face 3 is weakened by fracturing, and the impact ground pressure working face is relieved and prevented;

[0040] Furthermore, a large-flow high-pressure pump is used for fracturing with a rated pressure of 66MPa. The fracturing method is backward multi-stage fracturing, with fracturing every 3m. When the water output from the orifice is large, the fracturing interval can be adjusted to 4.5m. The fracturing time is tentatively set at 30min, which will be adjusted according to the changes in water pressure and water output from the rock formation. The expected pressure maintenance pressure is between 15MPa and 40MPa.

[0041] Deep hole pre-splitting blasting pressure relief scheme: The construction scope of the pressure relief borehole 8 is 150m ahead of the working face, arranged on the side roadway of the working face of the two lanes, the distance from the borehole mouth to the roadway floor is 0.5m to 1.0m, the drilling direction is perpendicular to the roadway wall, and is set in the direction of the working face 3. The drilling depth is 90m, and the hole spacing is 5m. The blasting pressure relief borehole 8 adopts the third-level coal mine permitted emulsion explosive forward charging, and the explosive is fixed at the top of the blasting hole with a fixing block, and the remaining rear is empty. The charge of each blasting hole is 5kg, and the sealing hole length is not less than 1 / 3 of the hole depth;

[0042] Furthermore, the third-level coal mine permitted emulsion explosives are loaded into the blasting holes in sequence, and the explosives are fixed at the top of the blasting holes with fixed blocks, with the remaining rear part being empty; forward loading is performed, and the blasting hole mouth is sealed with damp blasting soil loaded in a kraft paper roll and poked in with a wooden blasting stick.

[0043] Step 4: Perform mining operations on working face 3;

[0044] For the coal seam part of the working face, 6 coal shearers cut coal in both directions, push conveyors, and pull hydraulic supports;

[0045] For the inclined portion 7 of the working face, the shearer cuts coal in one direction;

[0046] The one-way coal cutting is that the coal is not cut when going up, but is cut when going down; that is, when the coal mining machine moves from the return mining roadway 4 along the inclined part 7 of the working face to the coal seam part 6 of the working face, it is going up, at which time the coal mining machine does not cut coal for the inclined part 7 of the working face; when the coal mining machine moves from the coal seam part 6 of the working face along the inclined part 7 of the working face to the return mining roadway 4, it is going down, at which time the coal mining machine cuts coal for the inclined part 7 of the working face;

[0047] When the coal mining machine is moving upward without cutting coal, the front conveyor is pushed from bottom to top along the upward direction of the coal mining machine, the hydraulic support is pulled, the rear conveyor is pulled, and the top coal is released;

[0048] When the coal mining machine is going down to cut coal, it does not push the conveyor, pull the hydraulic support, or put the top coal;

[0049] Furthermore, when pulling the hydraulic support, the telescopic beam of the hydraulic support should be extended first, and the hydraulic support should be pulled with initial pressure and close to the top plate of the inclined part 7 of the working surface, that is, the hydraulic support should be ensured to be in contact with the top plate of the inclined part 7 of the working surface, and then the telescopic beam of the hydraulic support should be gradually retracted. After it is in place, the hydraulic support should be raised in time to ensure the initial supporting force of the hydraulic support.

[0050] Furthermore, when top coal is placed on the inclined portion 7 of the working face, the hydraulic supports are pulled one by one from bottom to top along the upward direction of the coal mining machine.

[0051] The above embodiments only express the preferred implementation modes of the present invention. It should be pointed out that, for those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A layout structure of mining tunnels in a rock burst working face, comprising two mining tunnels (4) arranged in parallel, wherein the two mining tunnels (4) are entirely located in a stable rock layer (2) below a coal seam (1), and a working face (3) is located between the two mining tunnels (4); It is characterized in that The working face (3) comprises a working face coal seam portion (6) which is entirely located in the coal seam (1) and a working face inclined portion (7) which extends from both ends of the working face coal seam portion (6) to the ends of the mining tunnel (4) and passes through the working face inclined portion (7) and has an inclination angle (5) with the bottom plate of the mining tunnel (4).

2. The arrangement structure of the mining tunnel in the rock burst working face according to claim 1 is characterized in that: The angle of the tilt adjustment angle (5) is 5° to 10°.

3. A method for preventing and controlling rock burst at a working face, characterized in that: The following steps are involved: Step 1: Arrange two mining tunnels (4) as a whole in a stable rock layer (2) below the coal seam (1); Step 2: a working face (3) which is entirely located in the coal seam (1) is arranged between the two mining tunnels (4); The working face (3) comprises a working face coal seam portion (6) which is entirely located in the coal seam (1) and a working face inclined portion (7) which extends from both ends of the working face coal seam portion (6) to the ends of the mining tunnels (4) on both sides, and an adjustment angle (5) is formed between the working face inclined portion (7) and the bottom plate of the mining tunnel (4); Step 3: Drill holes in the bottom plate of the working surface (3) to relieve pressure; A pressure relief borehole (8) is drilled into the stable rock layer (2) at the side walls of the working faces (3) of the two mining tunnels (4), and hydraulic fracturing or deep hole pre-splitting blasting is used to relieve pressure in the pressure relief borehole 8; Step 4: Perform mining operations on the working face (3); During the mining operation, the coal mining machine located in the coal seam part (6) of the working face cuts coal in both directions, pushes the conveyor, and pulls the hydraulic support; The coal mining machine located at the inclined part (7) of the working face cuts coal in one direction, wherein the one-way coal cutting does not cut coal in the upward direction but cuts coal in the downward direction; When the coal mining machine is moving upward without cutting coal, the front conveyor is pushed from bottom to top along the upward direction of the coal mining machine, the hydraulic support is pulled, the rear conveyor is pushed, and the top coal is caving; When the coal mining machine goes down to cut coal, it does not push the conveyor, pull the hydraulic support, or release the top coal.

4. The method for preventing and controlling rock burst in a working surface according to claim 3, characterized in that: In the step 2, the angle of the bevel angle (5) is adjusted to 5° to 10°.

5. The method for preventing and controlling rock burst in a working surface according to claim 3, characterized in that: In the step three, the pre-cracking range of the pressure relief borehole (8) is the bottom plate directly below the coal seam portion (6) of the working face.

6. The method for preventing and controlling rock burst in a working surface according to claim 5, characterized in that: In the step three, the depth of the pressure relief borehole (8) when hydraulic fracturing is adopted is 80m-90m, and the hole spacing is 10m-20m; the depth of the pressure relief borehole (8) when deep hole pre-splitting blasting is adopted is 80m-90m, and the hole spacing is 5m-10m, and the charge amount of each blasting hole is 5kg-10kg.

7. The method for preventing and controlling rock burst in a working surface according to claim 3, characterized in that: In the step 4, when pulling the hydraulic support, the telescopic beam of the hydraulic support should be extended first, and the hydraulic support is pulled by using the top plate with initial pressure and close to the inclined part (7) of the working surface.

8. The method for preventing and controlling rock burst in a working surface according to claim 3, characterized in that: In the step 4, when the top coal is placed in the inclined part (7) of the working face, the hydraulic supports are pulled one by one from bottom to top along the upward direction of the coal mining machine.

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