Opposite energy-gathering blasting method for danger area of high gas coal seam impact

Abstract

The present application belongs to the technical field of rock burst prevention, and discloses a method for relieving danger by opposite energy-gathering blasting in a high-gas coal seam rock burst danger zone. A pre-pressure relief borehole is drilled in the coal seam in a roadway, and two rows of blasting boreholes are drilled above and below the pre-pressure relief borehole. Explosive charges are selected from the two rows of blasting boreholes and placed in energy-gathering covers, and the remaining boreholes are conventionally sealed and connected to extraction pipelines. Adjacent blasting boreholes are grouped and simultaneously detonated. The pre-pressure relief borehole and the blasting boreholes are arranged in rows, providing a deformation space for energy-gathering blasting, improving the utilization rate of explosive energy, and more fully breaking the coal in the area of the explosive charge blasting, which achieves better pressure relief and effectively relieves local danger. The present application performs opposite blasting on grouped boreholes in a stress concentration area, greatly improves the degree of coal fragmentation, causes the remaining gas to rapidly desorb and outflow, and uses the unblasted boreholes in the row to quickly and timely extract the pressure relief gas, avoiding gas overrun accidents in the roadway.

Description

Technical Field

[0001] This invention belongs to the field of rockburst prevention and control technology, specifically relating to a method for resolving rockburst hazards in high-gas coal seam rockburst hazard areas using opposing shaped charge blasting. Background Technology

[0002] Coal will remain the mainstay of my country's energy consumption for a long time. However, with the increase in the depth of coal mining, the risk of rock bursts is gradually increasing, and there is an urgent need for efficient local mitigation methods.

[0003] Large-diameter borehole drilling in coal seams is a commonly used technique for controlling rockbursts, creating localized pressure relief zones within the coal seam to achieve localized rockburst prevention. However, during longwall mining, when encountering high-risk areas for rockbursts, it is essential to implement rockburst mitigation measures, such as deep-hole blasting to enhance local pressure relief and eliminate localized hazards. In practice, the layout of deep-hole blasting drill holes is affected by the location of existing pre-pressure relief drill holes, impacting the blasting effect. To efficiently utilize the blasting energy, the layout of the blasting drill holes and the charging method need optimization. Simultaneously, the use of enhanced blasting measures leads to coal seam fracturing, causing localized large-scale gas outbursts and exceeding gas limits in some roadways. Therefore, for high-gas coal seam rockburst hazard areas, measures for both blasting pressure relief and prevention of gas exceeding limits must be considered simultaneously.

[0004] Therefore, it is necessary to propose a deep-hole blasting technology suitable for areas with high gas coal seam rockburst hazards, which can not only ensure the efficient use of blasting energy, but also effectively relieve pressure in high-risk areas and prevent gas exceedances, thereby achieving the goal of local hazard relief. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for resolving the hazard of high-gas coal seam impact zones using counter-directional shaped charge blasting. This method utilizes the guiding effect of existing pressure relief boreholes and employs counter-directional shaped charge blasting to fully relieve pressure in high-stress areas and promptly extract pressure-relieving gas, thereby effectively resolving the hazard in the dangerous zone.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A counter-shaped charge blasting method for hazardous areas of high-gas coal seams includes the following steps:

[0008] A set of pre-pressure relief boreholes were drilled into the coal seam within the roadway;

[0009] The first row of blasting boreholes is constructed above the pre-decompression boreholes, and the second row of blasting boreholes is constructed below the pre-decompression boreholes.

[0010] Select the 4N+4th borehole in the first row of blasting boreholes, where N = 0, 1, ... Fill the selected borehole with explosive charge, place a downward-facing shaped charge shield above the explosive charge, seal the boreholes in the first row of blasting boreholes, and connect the extraction pipeline to the boreholes that are not filled with explosive charge.

[0011] In the second row of blasting boreholes, select the 4N+1th borehole, N = 0, 1, ..., fill the selected borehole with explosive charge, place an upward-facing shaped charge below the explosive charge, seal the boreholes in the second row of blasting boreholes, and connect the extraction pipeline to the boreholes that are not filled with explosive charge.

[0012] Several adjacent explosive charges were grouped together and detonated simultaneously.

[0013] Furthermore, the pre-decompression boreholes, the first row of blasting boreholes, and the second row of blasting boreholes are distributed in parallel in a horizontal direction.

[0014] Furthermore, the boreholes in the first row of blasting boreholes and the boreholes in the pre-decompression boreholes are distributed at equal intervals in the horizontal direction, and the boreholes in the second row of blasting boreholes and the boreholes in the pre-decompression boreholes are distributed at equal intervals in the horizontal direction.

[0015] Furthermore, the explosive charges filled in the first row of blasting boreholes and the explosive charges filled in the second row of blasting boreholes are distributed at equal intervals in the horizontal direction.

[0016] Furthermore, the distance between the pre-decompression borehole and the first row of blasting boreholes and the second row of blasting boreholes is not less than 1m.

[0017] Furthermore, the diameter of the pre-decompression drill hole is not less than Φ153mm, the hole spacing is 1~3m, the hole depth is 20~30m, and the height of the drill hole from the bottom plate is 1.5m~1.8m.

[0018] Furthermore, the borehole diameter of the first row of blasting boreholes is Φ75~94mm, the spacing between boreholes is 1~3m, and the depth is 20~30m.

[0019] Furthermore, the borehole diameter of the second row of blasting boreholes is Φ75~94mm, the spacing between boreholes is 1~3m, and the depth is 20~30m.

[0020] Furthermore, the openings of the first row of blasting boreholes and the second row of blasting boreholes are sealed within a 10m length.

[0021] Furthermore, the downward focusing shield and the upward focusing shield are semi-circular structures.

[0022] The beneficial effects of this invention are:

[0023] 1. The pre-decompression boreholes and blasting holes are arranged in rows, providing deformation space for shaped charge blasting, improving the utilization rate of explosive energy, and resulting in more thorough coal body fragmentation in the blasting area, better decompression effect, and effective local risk mitigation. Moreover, the shaped charge blasting method releases energy into the coal seam, effectively reducing damage to the roof and floor, which is beneficial for roof and floor control during mining.

[0024] 2. In areas of stress concentration, grouped boreholes are blasted in opposite directions, which greatly increases the degree of coal fragmentation, allowing residual gas to be rapidly desorbed and released. Meanwhile, rows of unblasted boreholes can be used to quickly and timely pump out the depressurized gas, thus preventing gas over-limit accidents in the roadway. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the arrangement of the pre-decompression drilling holes, the first row of blasting drilling holes, and the second row of blasting drilling holes in this embodiment;

[0027] Figure 2 This is a schematic diagram of the explosive drilling, charging, and sealing process in this embodiment.

[0028] Figure 3 This is a schematic diagram of the installation of the explosive charge and the shaped charge in this embodiment;

[0029] Figure 4 This is a schematic diagram of the direction of explosive energy release in this embodiment;

[0030] Figure 5 This is a schematic diagram of the burst fracture in this embodiment.

[0031] In the diagram: 1. Coal seam; 2. Pre-decompression borehole; 3. First row of blasting boreholes; 4. Downward shaped charge; 5. Second row of blasting holes; 6. Upward shaped charge; 7. Blasting charge; 8. Roadway. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0034] As coal mining depth increases, the intensity and severity of rockbursts in deep, high-gas coal seams become increasingly serious, necessitating effective local mitigation methods to reduce their hazards. During longwall mining, rockburst prevention and mitigation measures must be implemented in high-risk areas. If deep-hole blasting is used, the layout of the deep-hole blasting mitigation boreholes is affected by the location of existing pre-decompression boreholes, thus impacting the blasting effectiveness.

[0035] like Figure 1-5 As shown, the method for counter-directional shaped charge blasting in high-gas coal seam impact hazard areas includes the following steps:

[0036] A set of pre-decompression boreholes 2 were drilled into coal seam 1 within roadway 8;

[0037] The first row of blasting boreholes 3 is constructed above the pre-decompression borehole 2, and the second row of blasting boreholes 5 is constructed below the pre-decompression borehole 2.

[0038] In the first row of blasting boreholes 3, select the 4N+4th borehole, N=0, 1..., fill the selected borehole with explosive charge 7, place a downward-facing shaped charge 4 above the explosive charge 7, seal the boreholes in the first row of blasting boreholes 3, and connect the extraction pipeline to the boreholes that are not filled with explosive charge 7.

[0039] In the second row of blasting boreholes 5, select the 4N+1th borehole, N = 0, 1, ..., fill the selected borehole with explosive charge 7, place an upward-facing shaped charge 6 below the explosive charge 7, seal the boreholes in the second row of blasting boreholes 5, and connect the extraction pipeline to the boreholes that are not filled with explosive charge 7.

[0040] Several adjacent explosive charges 7 were grouped together and detonated simultaneously.

[0041] This embodiment optimizes the spatial positioning of the pre-decompression boreholes and blasting holes. A semi-circular shaped charge hood guides the blasting energy, achieving efficient and full utilization of the blasting energy. The presence of the pre-decompression boreholes provides displacement space for the shaped charge blasting, resulting in more thorough coal body fragmentation in the area. Residual gas will rapidly desorb and escape, and the unblasted rows of boreholes can quickly and promptly pump out the decompression gas, preventing gas exceedance accidents in the roadway.

[0042] Specifically, the pre-decompression borehole 2, the first row of blasting boreholes 3, and the second row of blasting boreholes 5 are distributed in parallel in a horizontal direction.

[0043] Specifically, the boreholes in the first row of blasting boreholes 3 and the boreholes in the pre-decompression boreholes 2 are distributed at equal intervals in the horizontal direction, and the boreholes in the second row of blasting boreholes 5 and the boreholes in the pre-decompression boreholes 2 are distributed at equal intervals in the horizontal direction.

[0044] Specifically, the explosive charges 7 filled in the first row of blasting boreholes 3 and the explosive charges 7 filled in the second row of blasting boreholes 5 are distributed at equal intervals in the horizontal direction.

[0045] Specifically, the distance between the pre-decompression borehole 2 and the first row of blasting boreholes 3 and the second row of blasting boreholes 5 shall not be less than 1m.

[0046] Specifically, the diameter of the pre-decompression borehole 2 is not less than Φ153mm, the spacing between holes is 1 to 3m, the hole depth is 20 to 30m, and the height of the borehole from the bottom plate is 1.5m to 1.8m.

[0047] Specifically, the borehole diameter of the first row of blasting boreholes 3 is Φ75~94mm, the spacing between the boreholes is 1~3m, and the depth is 20~30m.

[0048] Specifically, the borehole diameter of the second row of blasting boreholes 5 is Φ75~94mm, the spacing between boreholes is 1~3m, and the depth is 20~30m.

[0049] Specifically, the holes in the first row of blasting boreholes 3 and the second row of blasting boreholes 5 are sealed within a 10m length inward from their openings.

[0050] Specifically, the downward focusing shield 4 and the upward focusing shield 6 are semi-circular structures.

[0051] The invention will be further described below through specific operational steps:

[0052] Step 1: According to the requirements for large-diameter drilling in coal mines, before the working face is mined, a row of pre-pressure relief boreholes 2 are drilled in roadway 8 into coal seam 1. The borehole diameter is Φ153mm, the spacing between boreholes is 3m, the depth of the borehole is 30m, and the height of the borehole from the bottom plate is 1.8m.

[0053] Step 2: In the high-risk area of ​​rockburst, construct the first row of blasting boreholes 3 and the second row of blasting boreholes 5 1m above and below the pre-decompression borehole 2. The boreholes in the first row of blasting boreholes 3 and the second row of blasting boreholes 5 are arranged at intervals with the boreholes in the pre-decompression borehole 2. The diameter of the first row of blasting boreholes 3 and the second row of blasting boreholes 5 is Φ90mm, and the spacing and depth of the boreholes are the same as those of the pre-decompression borehole 2.

[0054] Step 3: Select boreholes 1, 5, and 9 in the first row of blasting boreholes 3. Charge the boreholes from the bottom outwards. Place a downward-facing semi-circular shaped charge shield 4 above the explosive charge 7. Seal the boreholes within 10 meters outside the first row of blasting boreholes 3 using conventional sealing methods. Seal the boreholes within 10 meters outside the first row of blasting boreholes 2, 3, 4, 6, 7, 8, 10, 11, and 12 using conventional sealing methods, and connect the extraction pipeline.

[0055] Step 4: Select boreholes 4, 8, and 12 in the second row of blasting boreholes 5. Charge the boreholes from the bottom outwards. Place an upward-facing semi-circular shaped charge shield 6 below the explosive charge 7. Seal the boreholes within 10 meters outside the second row of blasting boreholes 5 using conventional sealing methods. Seal the boreholes within 10 meters outside the second row of blasting boreholes 1, 2, 3, 5, 6, 7, 9, 10, and 11 using conventional sealing methods, and connect the extraction pipeline.

[0056] Step 5: Simultaneously detonate the 1st, 5th, and 9th blasting holes in the first row of blasting holes 3 and the 4th, 8th, and 12th blasting holes in the second row of blasting holes 5.

[0057] Figure 4 This is a schematic diagram of the direction of explosive energy release in this embodiment. Figure 5 This is a schematic diagram of the blasting fracture in this embodiment. For coal seams in areas with high impact risk, to achieve pressure relief and impact prevention, a certain number of large-diameter pressure relief boreholes are typically drilled within the coal seam. When mining stress increases significantly, the boreholes break, and fractures form in the coal body around the boreholes, thus achieving local impact prevention. However, this is a passive method of destruction and pressure relief. For areas with high impact risk, active methods must be used to fracture and relieve pressure in the coal body of that area. Blasting is a common fracturing method, but if only explosives are used to blast the boreholes, excessive blasting energy will be wasted in the fractured area around the borehole. When a free surface exists around the blast hole, the blasting energy will be used to form fractures connecting the free surface and the blasting borehole, thereby achieving the purpose of fracturing and pressure relief. In engineering, it is preferable that the blasting energy is mainly used to create fractures within the coal seam, and that the blasting energy is not allowed to expand indefinitely and be wasted on the roof and floor strata. At this point, it is advisable to construct a row of blasting boreholes near the top and bottom plates. By utilizing the directional energy-concentrating cover, the blasting energy can be released in a predetermined direction. Meanwhile, the large-diameter pressure-relief boreholes and the adjacent row of blasting boreholes can provide free surfaces and displacement space, thereby achieving active fracturing and pressure relief of the coal body within the control area.

[0058] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for counter-concentrated blasting for danger area of high gas coal seam, characterized in that, The method comprises the following steps: a group of pre-pressure relief boreholes (2) are drilled in the coal seam (1) in the roadway (8); a first row of blasting boreholes (3) are drilled above the pre-pressure relief boreholes (2) and a second row of blasting boreholes (5) are drilled below the pre-pressure relief boreholes (2); 4N+4 boreholes in the first row of blasting boreholes (3) are selected, N=0, 1, …, explosive columns (7) are filled in the selected boreholes, downward converging covers (4) are placed above the explosive columns (7), the boreholes in the first row of blasting boreholes (3) are sealed, and the boreholes not filled with explosive columns (7) are connected with the extraction pipeline; 4N+1 boreholes in the second row of blasting boreholes (5) are selected, N=0, 1, …, explosive columns (7) are filled in the selected boreholes, upward converging covers (6) are placed below the explosive columns (7), the boreholes in the second row of blasting boreholes (5) are sealed, and the boreholes not filled with explosive columns (7) are connected with the extraction pipeline; a plurality of adjacent explosive columns (7) are grouped and simultaneously detonated.

2. The method for counter-concentrated blasting of danger area of high gas coal seam according to claim 1, characterized in that, The pre-pressure relief boreholes (2), the first row of blasting boreholes (3) and the second row of blasting boreholes (5) are horizontally and parallelly distributed.

3. The method for counter-concentrated blasting of danger area of high gas coal seam according to claim 1, characterized in that, The boreholes in the first row of blasting boreholes (3) and the boreholes in the pre-pressure relief boreholes (2) are equidistantly and horizontally distributed, and the boreholes in the second row of blasting boreholes (5) and the boreholes in the pre-pressure relief boreholes (2) are equidistantly and horizontally distributed.

4. The method for counter-concentrated blasting of danger area of high gas coal seam according to claim 1, characterized in that, The explosive columns (7) filled in the first row of blasting boreholes (3) and the explosive columns (7) filled in the second row of blasting boreholes (5) are equidistantly and horizontally distributed.

5. The method for counter-concentrated blasting of danger area of high gas coal seam impact according to claim 1, characterized in that, The distance between the pre-pressure relief boreholes (2) and the first row of blasting boreholes (3) and the second row of blasting boreholes (5) is not less than 1 m.

6. The method for counter-concentrated blasting of danger area of high gas coal seam impact according to claim 1, characterized in that, The borehole diameter of the pre-pressure relief boreholes (2) is not less than Φ153 mm, the hole spacing is 1-3 m, the hole depth is 20-30 m, and the distance from the borehole to the floor is 1.5-1.8 m.

7. The method for counter-concentrated blasting of danger area of high gas coal seam impact according to claim 1, characterized in that, The borehole diameter of the first row of blasting boreholes (3) is Φ75-94 mm, the hole spacing is 1-3 m, and the hole depth is 20-30 m.

8. The method for counter-concentrated blasting of danger area of high gas coal seam according to claim 1, characterized in that, The borehole diameter of the second row of blasting boreholes (5) is Φ75-94 mm, the hole spacing is 1-3 m, and the hole depth is 20-30 m.

9. The method for counter-concentrated blasting of danger area of high gas coal seam impact according to claim 1, characterized in that, The orifices of the first row of blasting boreholes (3) and the second row of blasting boreholes (5) are sealed within a 10 m length range inward.

10. The method for counter-concentrated blasting of danger area of high gas coal seam impact according to claim 1, characterized in that, The downward converging cover (4) and the upward converging cover (6) are semicircular structures.

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