CN111456732B - Coal seam top coal pre-splitting method - Google Patents
Coal seam top coal pre-splitting method Download PDFInfo
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- CN111456732B CN111456732B CN202010290065.XA CN202010290065A CN111456732B CN 111456732 B CN111456732 B CN 111456732B CN 202010290065 A CN202010290065 A CN 202010290065A CN 111456732 B CN111456732 B CN 111456732B
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- 239000003245 coal Substances 0.000 title claims abstract description 141
- 238000000034 method Methods 0.000 title claims abstract description 25
- 230000035939 shock Effects 0.000 claims abstract description 53
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000005553 drilling Methods 0.000 claims abstract description 14
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- 238000004146 energy storage Methods 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 5
- 230000003044 adaptive effect Effects 0.000 claims 1
- 239000002360 explosive Substances 0.000 abstract description 11
- 238000005336 cracking Methods 0.000 abstract description 10
- 230000007613 environmental effect Effects 0.000 abstract description 7
- 238000005065 mining Methods 0.000 description 10
- 230000000694 effects Effects 0.000 description 8
- 238000005422 blasting Methods 0.000 description 4
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- 238000006243 chemical reaction Methods 0.000 description 3
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- 238000004880 explosion Methods 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 238000010891 electric arc Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
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- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
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- 239000002699 waste material Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
- E21C41/16—Methods of underground mining; Layouts therefor
- E21C41/18—Methods of underground mining; Layouts therefor for brown or hard coal
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C37/00—Other methods or devices for dislodging with or without loading
- E21C37/18—Other methods or devices for dislodging with or without loading by electricity
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Abstract
The invention relates to a method for pre-cracking coal at the top of a coal bed, which aims to solve the problems of high risk and poor environmental protection in the prior process of pre-cracking the coal at the top of the coal bed by using explosives. The coal seam top coal pre-splitting method comprises the following steps; s1, setting the positions and the number of drill holes on the top coal, drilling the drill holes on the top coal, wherein the depth of each drill hole extends into the top plate of the coal seam, and the included angle between the axis of each drill hole and the direction of a roadway is 30-60 degrees; s2, installing an orifice device in each drill hole, and then filling the drill holes with water; s3, connecting an energy converter with a pulse power driving source, and placing the energy converter in the borehole; s4, starting a pulse power driving source to discharge to an energy converter, and fracturing the top coal by shock waves generated by the energy converter, wherein the intensity of the shock waves is 200-209 MPa; and (4) forming a seam network by the cracks generated after the plurality of drill holes are subjected to shock wave operation, namely performing overall pre-cracking on the top coal.
Description
Technical Field
The invention belongs to the technical field of coal mining, and particularly relates to a coal seam top coal pre-splitting method.
Background
Mineral resources are the basis of industrialization, and the primary consumption energy of China mainly depends on coal supply, and the long-term occupation ratio reaches more than 60 percent, so that the mineral resources are the main pillars for the industrial development of China. At present, when a coal seam is mined, a coal face with the mining height of 2-3m is arranged along the bottom plate of the coal seam or the bottom of the coal seam within a certain thickness range, the mining is carried out in a comprehensive mechanical mode, top coal is broken into discrete bodies under the action of mine pressure or by means of loosening blasting and the like, the top coal is discharged from a coal discharge window behind or above a support, and the top coal is conveyed out of the working face by a scraper conveyor. However, when the coal seam belongs to a thick coal seam or a huge thick coal seam, the problem of resource waste of at least 8% is caused because the mechanical property of the coal seam is strong and the caving property of the top coal about 15 meters above two sides of a roadway is not good, so that the loosening and presplitting of the top coal through blasting become a conventional method in coal mining. The currently used initiating explosive and other initiating explosive are tools for effectively loosening and pre-splitting, but the shock wave generated by explosive blasting has poor controllability, high risk and poor environmental protection, so that the use of the explosive is more and more strictly controlled, and the coal resource exploitation efficiency is reduced.
Disclosure of Invention
The invention aims to provide a method for pre-cracking coal at the top of a coal seam, which aims to solve the problems of high risk and poor environmental protection in the process of pre-cracking the coal at the top of the coal seam by using explosives at present.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a coal bed top coal pre-splitting method comprises the following steps;
s1, setting the positions and the number of drill holes on the top coal, drilling the drill holes on the top coal, wherein the depth of each drill hole extends into the top plate of the coal seam, and the included angle between the axis of each drill hole and the direction of a roadway is 30-60 degrees;
s2, installing an orifice device in each drill hole, and then filling the drill holes with water;
s3, connecting an energy converter with a pulse power driving source, and placing the energy converter in the borehole;
s4, starting a pulse power driving source to discharge to an energy converter, and fracturing the top coal by shock waves generated by the energy converter, wherein the intensity of the shock waves is 200-209 MPa; and (4) forming a seam network by the cracks generated after the plurality of drill holes are subjected to shock wave operation, namely performing overall pre-cracking on the top coal.
Preferably, one or more operation sections are arranged in the drill hole, the distance between every two adjacent operation sections is 5-10m, the energy converter sequentially carries out shock wave operation on the operation sections from the deepest part of the drill hole to the outside, and a shock wave output window of the energy converter is aligned to the middle point of the operation sections.
Preferably, the energy converter includes ground electrode, high voltage electrode, insulation support, shell and cable interface, the shell is cylindric structure, and its inside cavity, high voltage electrode pass through insulation support to be fixed at the shell tip, and the cable conductor of cable interface tip passes shell body, insulation support are connected with the high voltage electrode rear end, and ground electrode sets up and is connected with the shell along the length direction of shell, and ground electrode sets up with the high voltage electrode front end relatively.
Preferably, the ground electrode is connected with the high-voltage electrode through a metal wire, and one metal wire is replenished on one side of the ground electrode after the energy converter discharges.
Preferably, the pulsed power drive source electrical energy storage is greater than 100 kJ.
Preferably, step S4 further includes observing the size of the crack generated by the top coal after fracturing, filling the drill hole with water if the width of the crack does not reach the set crack width, and starting the pulse power driving source to discharge again until the top coal crack reaches the set width, wherein the set crack width is larger than 10 nm.
Preferably, the orifice device comprises an expansion sleeve clamped at the orifice of the drill hole, the lower surface of an annular fixed plate at the upper end of the expansion sleeve is contacted with the edge of the drill hole, a tubular taper sleeve is sleeved in the expansion sleeve, a taper port at the lower end of the taper sleeve is clamped in an expansion sheet circumferentially arranged at the lower end of the expansion sleeve, the expansion sheet protrudes outwards and is in close contact with the wall of the drill hole, and the expansion sheet is elastically connected with the lower end of the expansion sleeve; the taper sleeve upper end left and right sides is equipped with the connecting plate, is equipped with the screw rod on the connecting plate, after the screw rod passed the screw hole on the connecting plate with butt board swing joint, butt board lower extreme with annular fixed plate upper surface contact is equipped with the check valve in the taper sleeve, the taper sleeve upper end be equipped with the connecting portion of energy converter adaptation are equipped with the sealing washer on the connecting portion.
The invention has the beneficial effects that:
1. according to the method for pre-splitting the top coal of the coal bed, provided by the invention, the top coal is pre-split through drilling and low-strength shock waves for many times, the coal bed is fractured by utilizing the fatigue effect principle, the method is safer and more environment-friendly, and the problems of high risk and poor environmental protection in the pre-splitting of the top coal of the coal bed caused by the shock waves generated by explosive explosion are solved.
2. The invention adopts the electro-hydraulic effect to generate shock waves, and can continuously work only by supplementing electric energy to the pulse power driving source, thereby improving the coal resource exploitation efficiency.
3. When the metal wire carries out the shock wave operation after being connected ground electrode and high-voltage electrode, can improve energy converter's conversion efficiency, and then promoted the effect that sends and splits the coal seam.
4. The coal seam top coal pre-splitting method provided by the invention improves the environmental protection and safety of coal resource exploitation.
Drawings
FIG. 1 is a cross-sectional view of a coal face;
FIG. 2 is a cross-sectional view of FIG. 1;
FIG. 3 is a schematic diagram of an energy converter;
FIG. 4 is a schematic view of the structure of an orifice device;
fig. 5 is a cross-sectional view of fig. 4.
The reference numbers are as follows:
1-ground electrode, 2-metal wire, 3-high voltage electrode, 4-insulating support, 5-shell, 6-cable interface, 7-coal drop, 8-top coal, 9-coal seam roof, 10-roadway, 11-drilling, 12-orifice device, 13-energy converter, 20-expansion sleeve, 21-annular fixing plate, 22-taper sleeve, 23-expansion sheet, 24-connecting plate, 25-screw rod, 26-abutting plate, 27-one-way valve and 28-sealing ring.
Detailed Description
The invention is described in further detail below with reference to the following figures and specific examples:
a method of pre-splitting coal at the top of a coal seam includes an energy converter 13 and an orifice device 12.
As shown in fig. 3, the energy converter 13 includes a ground electrode 1, a wire 2, a high voltage electrode 3, an insulating support 4, a housing 5, and a cable interface 6.
The shell 5 is a cylindrical structure, the interior of the shell is hollow, the high-voltage electrode 3 is fixed at the end part of the shell 5 through the insulating support 4, a cable at the end part of the cable connector 6 penetrates through the body of the shell 5 and the insulating support 4 and then is connected with the rear end of the high-voltage electrode 3, the ground electrode 1 is arranged along the length direction of the shell 5 and is connected with the shell 5, and the ground electrode 1 is arranged opposite to the front end of the high-voltage electrode 3. As shown in fig. 3, the ground electrode 1, the high voltage electrode 3, and the connection portion between the ground electrode 1 and the housing 5 are open tubular structures, and the exposed portion between the ground electrode 1 and the high voltage electrode 3 is the shock wave output window.
The ground electrode 1 and the high-voltage electrode 3 are connected through a metal wire 2. The metal wire 2 can be selectively used, and when the metal wire 2 is used for carrying out shock wave operation after the ground electrode 1 and the high-voltage electrode 3 are connected, the conversion efficiency of the energy converter 13 can be improved, and then the effect of fracturing the top coal 8 is improved.
As shown in fig. 4 and 5, the orifice device 12 includes an expansion sleeve 20 that is clamped at the orifice of the drill hole 11, the lower surface of an annular fixing plate 21 at the upper end of the expansion sleeve 20 contacts with the edge of the drill hole 11, a tubular taper sleeve 22 is sleeved in the expansion sleeve 20, a taper port at the lower end of the taper sleeve 22 is clamped in an expansion sheet 23 circumferentially arranged at the lower end of the expansion sleeve 20, the expansion sheet 23 protrudes outwards and is in close contact with the hole wall of the drill hole 11, the orifice device 12 is further fixed with the drill hole 11, the expansion sheet 23 is elastically connected with the lower end of the expansion sleeve 20, the elastic connection facilitates the automatic recovery of the expansion sheet 23 to the original position, and the expansion sheet 23 can protrude outwards again to fix the orifice device 12.
Connecting plates 24 are arranged on the left side and the right side of the upper end of the taper sleeve 22, screw rods 25 are arranged on the connecting plates 24, the screw rods 25 penetrate through threaded holes in the connecting plates 24 and are movably connected with abutting plates 26, the lower end of the abutting plates 26 is in contact with the upper surface of the annular fixing plate 21, the taper sleeve 22 can be moved upwards when the screw rods 25 are rotated to move downwards, then a taper port at the lower end of the taper sleeve 22 can be clamped at the lower end of the expansion sleeve 20, and therefore the expansion sheet 23 protrudes outwards and is in close contact with the hole wall of the drilled hole 11, when the taper sleeve 22 moves downwards, the taper port at the lower end of the taper sleeve 22 can be separated from the expansion sheet 23, and the hole opening device 12 can be taken down.
Be equipped with check valve 27 in the taper sleeve 22, check valve 27 can avoid a large amount of water to flow out from drilling 11 when the water injection finishes, taper sleeve 22 upper end be equipped with the connecting portion of energy converter 13 adaptation are equipped with sealing washer 28 on the connecting portion, and when drilling 11 was put into to energy converter 13 front end, energy converter 13 rear end was connected fixedly through above-mentioned connecting portion, and sealing washer 28 can be sealed the junction and then avoid drilling 11 in the water flow.
The working principle of the invention is that a pulse power driving source is adopted to discharge the metal wire 2 arranged between the ground electrode 1 and the high-voltage electrode 3, and the discharge current causes the metal wire 2 to explode electrically to form a plasma arc channel (when the metal wire 2 is not adopted, the pulse power driving source directly discharges water between the ground electrode 1 and the high-voltage electrode 3, and high-voltage pulses generated after discharge can puncture a water gap to form the plasma arc channel); the generated plasma electric arc directly heats water under subsequent strong discharge current, rapidly heats, gasifies and expands surrounding water media, further pushes the surrounding water to generate spherical wave shock waves, and the spherical wave shock waves can fracture the top coal 8. The intensity of the shock wave can be controlled according to the energy storage and output voltage of the pulse power driving source.
The method for pre-splitting the coal seam top coal provided by the invention specifically comprises the following steps, referring to fig. 1 and fig. 2;
s1, setting an operation scheme of the top coal 8 according to the mechanical property of the top coal 8 and the effective distance of the top coal 8 fractured by the shock wave; the operation plan includes the positions and the number of the boreholes 11, and the intensity and the number of times the shock wave is conducted per borehole 11. Preferably, the diameter of the drill hole 11 is 113-153mm, and the distance between two adjacent drill holes 11 is 15-20 m; the presplitting precision of the area to be jacked can be controlled by setting the positions and the number of the drill holes 11, namely by setting the density of the drill holes 11; the pre-cracking degree of the top coal 8 to be caving can be controlled by setting the intensity of the shock wave and the acting times.
Before the operation scheme is set, the drill holes 11 in the top coal 8 are subjected to shock wave tests with different strengths, after the shock wave tests are completed, the top coal 8 after pre-splitting is inspected by using an endoscope or a three-dimensional seismic exploration method, so that the fracture size and range and the shock wave implementation strength and times suitable for the top coal 8 can be obtained.
One or more operation sections are arranged in the drill hole 11, preferably the distance between two adjacent operation sections is 5-10m, the fracturing effect of a plurality of operation sections is better, the energy converter 13 carries out shock wave operation on the operation sections from the deepest part of the drill hole 11 to the outside in sequence, and a shock wave output window of the energy converter 13 is aligned to the middle point of the operation sections.
The depth of the drill hole 11 extends to the inside of the coal seam roof 9, and the top coal 8 below the coal seam roof 9 can be completely fractured by extending to the coal seam roof 9, so that the top coal 8 can be completely mined. If the depth of the drill hole 11 extends to the end of the top coal 8, the gas in the drill hole 11 will limit the cracking range of the energy converter 13, so that part of the top coal 8 cannot be cracked; the drill hole 11 is obliquely arranged upwards towards one side of the coal mining upper, and preferably, the included angle between the axis of the drill hole 11 and the direction of the roadway 10 is 30-60 degrees. The top coal 8 is pre-cracked by drilling 11 through a plurality of times of low-intensity shock waves, preferably with the intensity of the shock waves being 200-. After one working section has completed the shock wave operation, the shock wave operation is performed sequentially outwardly for the remaining working sections of the borehole 11. The top coal 8 is pre-cracked multiple times and multiple points through the drill hole 11, so that the top coal 8 is pre-cracked integrally.
And drilling a drill hole 11 on the top coal 8 on one side of the coal mining upper according to the operation scheme.
S2, installing an orifice device 12 at each orifice of the borehole 11, the orifice device 12 being used to fix the energy converter 12 and to close the orifice, and filling the borehole 11 with water after installing the orifice device 12.
S3, connecting the energy converter 13 to the pulse power driving source through a coaxial cable; the pulse power driving source is arranged in the sealed shell in a self-integration mode, the electric energy storage of the pulse power driving source is larger than 100kJ, pure electric energy high voltage is output through the coaxial cable, and the impulse wave is generated through discharging of the energy converter 13.
The energy converter 13 is placed at the deepest operating point of the drill hole 11 by using the drilling machine, the shock wave output window of the energy converter 13 faces to the middle point of the deepest operating section of the drill hole 11, the ground electrode 1 and the high-voltage electrode 3 of the energy converter 13 are completely contacted with the water in the drill hole 11 to generate a plasma arc, and the generated plasma arc reacts with the water to form a shock wave which is output from the shock wave output window.
S4, starting the pulse power driving source to charge the energy storage capacitor, discharging the pulse power driving source to the energy converter 13 after the electric energy of the energy storage capacitor reaches the working threshold of the control switch, and fracturing the top coal 8 by the shock wave generated by the energy converter 13;
and observing the cracks formed by the top coal 8 after fracturing, filling water into the drill hole 11 if the maximum width of the crack does not reach 10nm (the set crack width is more than 10nm), and starting the pulse power drive source to discharge again until the cracks on the top coal 8 reach the set width.
In the embodiment, the width of the pre-cracked crack of the top coal 8 reaches more than 10nm after about 10 times of low-intensity shock wave operation through the drilling 11.
The pulse power drive source can generate a shock wave again by repeating charging and discharging; after the pulse power driving source discharges by using the metal wire 2, the metal wire 2 is scrapped after electric explosion, and when the discharge is performed again, one metal wire 2 needs to be replenished on one side of the ground electrode 1 of the energy converter 13.
The degree of the pre-splitting top coal 8 is controlled through the intensity of the shock wave and the number of times of the shock wave, the precision of the pre-splitting top coal 8 is controlled through the distance between the drill holes 11, so that the plurality of drill holes 11 generate cracks with set sizes, the cracks generated after the shock wave operation is implemented on the plurality of drill holes 11 form a seam network, the top coal 8 is also integrally pre-split, the management of the top coal 8 is not influenced before coal mining, the whole top coal 8 to be caving naturally caving in the coal mining process, and the recovery rate of coal resources is further improved.
In the coal mining process, if the top coal 8 has an area with insufficient pre-cracking degree, the top coal 8 in the area can be fully cracked by adding a new drilling hole 11, so that the smooth coal mining is ensured.
Through tests, the pulse power driving source drives the energy converter 13 to crack in the drill holes 11 of the crossheading top coal 8 on two sides of the working face 10, so that the top coal 8 is integrally pre-cracked, and the problem of recovery of the top coal 8 with the length of 30 meters can be solved; for a 12-meter thick coal seam, 80 million tons of top coal 8 can be recovered from a 2000-meter working face 10, and the yield is about 4 million yuan.
According to the method for pre-splitting the top coal of the coal bed, provided by the invention, the top coal is pre-split through drilling and low-strength shock waves for many times, the coal bed is fractured by utilizing the fatigue effect principle, the method is safer and more environment-friendly, and the problems of high risk and poor environmental protection in the pre-splitting of the top coal of the coal bed caused by the shock waves generated by explosive explosion are solved.
The invention adopts the electro-hydraulic effect to generate shock waves, and can continuously work only by supplementing electric energy to the pulse power driving source, thereby improving the coal resource exploitation efficiency.
When the metal wire carries out the shock wave operation after being connected ground electrode and high-voltage electrode, can improve energy converter's conversion efficiency, and then promoted the effect that sends and splits the coal seam.
The presplitting precision of the coal seam of the area to be jacked can be controlled by setting the positions and the number of the drill holes, namely by setting the density of the drill holes; the pre-cracking degree of the top coal to be caving can be controlled by setting the intensity of the shock wave and the operation times.
The invention utilizes the pulse power driving source to implement shock wave operation on the coal bed through the energy converter, the pulse power driving source directly discharges water between the ground electrode and the high-voltage electrode, the generated plasma electric arc directly heats the water under subsequent strong discharge current, and rapidly heats, gasifies and expands the surrounding water medium, thereby further pushing the peripheral water to generate spherical waves, and the spherical wave shock waves can fracture the coal bed top coal to finally form integral pre-fracture; the pulse power driving source can finely control the intensity of the output shock wave according to the stored energy and the output voltage, so that workers can conveniently control the intensity and the opportunity of the shock wave generated by the pulse power driving source, the safety in the fracturing process is improved, the life safety of production personnel is guaranteed, and the safety problem caused by the fact that blasting by using initiating explosive is not easy to control and the problem of mine pressure impact caused by explosive are avoided; meanwhile, the pulse power driving source can avoid the problem that toxic gas (such as nitrogen oxide and carbon monoxide) is generated when the initiating explosive device is exploded, so that the environmental protection property of coal resource exploitation is improved.
The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.
Claims (5)
1. A coal seam top coal pre-splitting method is characterized by comprising the following steps: comprises the following steps;
s1, setting the positions and the number of the drill holes (11) in the top coal (8), drilling the drill holes (11) in the top coal (8), wherein the depth of the drill holes (11) extends into the coal seam roof (9), and the included angle between the axis of the drill holes (11) and the roadway direction is 30-60 degrees;
s2, installing an orifice device (12) in each drill hole (11), and then filling the drill holes (11) with water; the orifice device (12) comprises an expansion sleeve (20) clamped at the orifice of the drill hole (11), the lower surface of an annular fixing plate (21) at the upper end of the expansion sleeve (20) is in contact with the edge of the drill hole (11), a tubular taper sleeve (22) is sleeved in the expansion sleeve (20), a taper port at the lower end of the taper sleeve (22) is clamped in an expansion sheet (23) circumferentially arranged at the lower end of the expansion sleeve (20), the expansion sheet (23) protrudes outwards and is in tight contact with the hole wall of the drill hole (11), and the expansion sheet (23) is in elastic connection with the lower end of the expansion sleeve (20); connecting plates (24) are arranged on the left side and the right side of the upper end of the taper sleeve (22), a screw rod (25) is arranged on each connecting plate (24), the screw rod (25) penetrates through a threaded hole in each connecting plate (24) and then is movably connected with the abutting plate (26), the lower end of each abutting plate (26) is in contact with the upper surface of the annular fixing plate (21), a one-way valve (27) is arranged in the taper sleeve (22), a connecting part adaptive to the energy converter (13) is arranged at the upper end of the taper sleeve (22), and a sealing ring (28) is arranged on each connecting part;
s3, connecting the energy converter (13) with a pulse power driving source, and placing the energy converter (13) in the drill hole (11); the energy converter (13) comprises a ground electrode (1), a high-voltage electrode (3), an insulating support (4), a shell (5) and a cable interface (6), wherein the shell (5) is of a cylindrical structure and is hollow inside, the high-voltage electrode (3) is fixed at the end part of the shell (5) through the insulating support (4), a cable at the end part of the cable interface (6) penetrates through the body of the shell (5), the insulating support (4) is connected with the rear end of the high-voltage electrode (3), the ground electrode (1) is arranged along the length direction of the shell (5) and is connected with the shell (5), and the ground electrode (1) is arranged opposite to the front end of the high-voltage electrode (3);
s4, starting a pulse power driving source to discharge to an energy converter (13), wherein the top coal (8) is fractured by shock waves generated by the energy converter (13), and the intensity of the shock waves is 200-209 MPa; cracks generated after the plurality of drill holes (11) are subjected to shock wave operation form a seam network, namely, the top coal (8) is integrally pre-cracked.
2. The method for pre-splitting coal at the top of a coal seam according to claim 1, wherein: one or more operation sections are arranged in the drill hole (11), the distance between every two adjacent operation sections is 5-10m, the energy converter (13) sequentially carries out shock wave operation on the operation sections from the deepest part of the drill hole (11) to the outside, and a shock wave output window of the energy converter (13) is aligned to the middle point of the operation sections.
3. The method for pre-splitting coal at the top of a coal seam according to claim 1, wherein: the ground electrode (1) is connected with the high-voltage electrode (3) through the metal wire (2), and after the energy converter (13) discharges, one metal wire (2) is replenished on one side of the ground electrode (1).
4. The method for pre-splitting coal at the top of a coal seam according to claim 1, wherein: the pulse power driving source has an electric energy storage larger than 100 kJ.
5. The method for pre-splitting coal at the top of a coal seam according to claim 1, wherein: and step S4, observing the size of the crack generated by the top coal (8) after fracturing, filling water into the drill hole (11) if the width of the crack does not reach the set crack width, and starting the pulse power driving source to discharge again until the crack of the top coal (8) reaches the set width, wherein the set crack width is more than 10 nm.
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| CN101644156A (en) * | 2009-07-17 | 2010-02-10 | 中国矿业大学 | Method for weakening coal-rock mass by hydraulic blasting and fracturing |
| CN206190285U (en) * | 2016-11-24 | 2017-05-24 | 曾庆平 | Hole packer for carbon dioxide blast tube |
| CN109538209A (en) * | 2018-09-11 | 2019-03-29 | 中国矿业大学 | A kind of reduction coal seam tight roof method based on electroporation |
| CN110195581A (en) * | 2019-05-31 | 2019-09-03 | 西安交通大学 | Energy converter and surge generator |
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