CN112145223A - Rope saw cutting device and coal bed gas permeability increasing and pressure relieving method - Google Patents
Rope saw cutting device and coal bed gas permeability increasing and pressure relieving method Download PDFInfo
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- CN112145223A CN112145223A CN202010944644.1A CN202010944644A CN112145223A CN 112145223 A CN112145223 A CN 112145223A CN 202010944644 A CN202010944644 A CN 202010944644A CN 112145223 A CN112145223 A CN 112145223A
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- 239000003245 coal Substances 0.000 title claims abstract description 75
- 238000005520 cutting process Methods 0.000 title claims abstract description 43
- 238000000034 method Methods 0.000 title claims abstract description 20
- 230000035699 permeability Effects 0.000 title claims abstract description 19
- 230000001965 increasing effect Effects 0.000 title claims abstract description 18
- 238000005553 drilling Methods 0.000 claims abstract description 6
- 230000009471 action Effects 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 230000000149 penetrating effect Effects 0.000 claims description 3
- 238000002474 experimental method Methods 0.000 claims description 2
- 238000005065 mining Methods 0.000 description 4
- 238000009954 braiding Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000003795 desorption Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 241000219122 Cucurbita Species 0.000 description 1
- 235000009852 Cucurbita pepo Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009933 burial Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003203 everyday effect Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000009958 sewing Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F7/00—Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C27/00—Machines which completely free the mineral from the seam
- E21C27/10—Machines which completely free the mineral from the seam by both slitting and breaking-down
- E21C27/12—Machines which completely free the mineral from the seam by both slitting and breaking-down breaking-down effected by acting on the vertical face of the mineral, e.g. by percussive tools
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
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- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Mechanical Engineering (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
Abstract
The invention discloses a wire saw cutting device and a coal bed gas permeability increasing and pressure relieving method, and relates to the field of coal bed gas pressure relief, wherein the device comprises a wire saw and an adjusting part; the method comprises the steps of S1, determining the effective drawing radius of the rope saw after cutting a seam; s2, determining the density and position of the drilled hole according to the effective drainage radius and drilling the hole; s3 cutting the whole coal seam by a wire saw; the whole surface of the coal bed is cut to form a large free space in a coal body, the surrounding coal body moves, deforms and flows rheologically to the direction of the free space, the stress balance of the coal body is broken repeatedly, and finally the coal body is in a new balance state.
Description
Technical Field
The invention relates to the field of coal seam gas pressure relief, in particular to a wire saw cutting device and a coal seam gas permeability increasing and pressure relief method.
Background
Along with the increase of the demand of economic development on coal in recent years, the mining strength and strength of mines are increased, so that most of the existing mines in China enter a deep mining stage. The increase of the coal bed burial depth increases the ground stress of the mine, the permeability of the coal bed and surrounding rocks becomes poor, the distance that the gas displaces to the earth surface increases and is favorable for sealing and storing the gas, the gas sealing state is good, the gas content is high, the mining depth and the ground stress are large, the coal bed is easy to destabilize under the action of high stress, and other factors cause that part of the original mines and coal beds without outburst danger start to generate power phenomena, the means of mining protective layers, pre-pumping the coal bed gas and the like are adopted to effectively release the ground stress and the gas potential in the coal beds, the original properties of the coal bodies are changed, most of the coal beds with outburst danger in China have the characteristics of low permeability and easy rheological property, and a plurality of mines can be mined or have regions which cannot be protected without protective layers, the conventional technology has large; the gas drainage quantity is unstable, the time is long, the operation is complicated, and finally the problems of high drainage cost, incomplete disaster control, delay and the like are caused.
Disclosure of Invention
The invention aims to solve the problems and designs a wire saw cutting device and a coal bed gas permeability increasing and pressure relieving method.
The invention realizes the purpose through the following technical scheme:
the rope saw cutting device is used for increasing and reducing the permeability of coal bed gas, and comprises a rope saw machine for crushing coal bodies and an adjusting piece for changing the relative position between a saw rope and the coal bodies in the rope saw machine, wherein a drill hole for penetrating the saw rope is distributed in a coal bed gas pressure reducing and permeability increasing area, during pressure reduction, the first end of the saw rope penetrates through the drill hole and is fixedly connected with the second end of the saw rope, and the saw rope cuts and cracks the coal bodies above the pressure reducing area.
Furthermore, the seam range of the coal body above the sawing rope slotting pressure relief area is 3-10 cm.
Further, a plurality of saw teeth are arranged on the sawing rope.
Further, the distance between two adjacent saw teeth ranges from 3 m to 5 m.
Furthermore, the adjusting part comprises at least two guide wheels for guiding the sawing rope and a moving part for moving the position of the guide wheels, the moving action ends of the moving part respectively act on the guide wheels, and the sawing rope is wound on the guide wheels.
Furthermore, the moving part comprises at least two hand-operated hoists, and the moving action end of one hand-operated hoist acts on one guide wheel.
Furthermore, the adjusting part also comprises a prop pulling winch, and the moving action end of the prop pulling winch acts on the rope sawing machine.
The coal seam permeability increasing and pressure relieving method comprises the following steps:
s1, determining the effective drainage radius of the rope saw after cutting;
s2, determining the drilling density and position of the gas to be drained according to the effective drainage radius of the cut seam, and drilling;
s3, cutting a seam on the whole coal seam by a sawing rope of the rope sawing machine, moving the position of a hand-operated block and positioning the position of a rope saw by a guide wheel, after the rope sawing machine is installed, starting a movable drainage pump or a low negative pressure drainage system, starting an upper high pressure water head and a lower high pressure water head, starting the rope sawing machine under the condition of no load, and crushing and cutting the coal body above a pressure relief area to generate a large number of new cracks on the coal body.
The invention has the beneficial effects that: the front guide wheel and the rear guide wheel and the sawing rope are adjusted by moving the manual gourd, a large free space is formed in a coal body due to the fact that the whole surface of a coal layer is damaged and cut, the surrounding coal body moves, deforms and flows in the direction of the free space, the stress balance of the coal body is broken repeatedly, and finally the coal body is in a new stress balance state; the coal body is expanded and deformed to form pores and crack system inside the coal body, so that favorable conditions are provided for efficient gas desorption and high-speed flow.
Drawings
FIG. 1 is a mounting structure diagram of the wire saw cutting device for permeability increasing and pressure relief of coal bed gas;
wherein corresponding reference numerals are:
1-a rope sawing machine, 2-a sawing rope, 3-a guide wheel, 4-a manual hoist, 5-a prop drawing winch and 6-a coal body.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "inside", "outside", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships that the products of the present invention are conventionally placed in use, or the orientations or positional relationships that are conventionally understood by those skilled in the art, and are used for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is also to be noted that, unless otherwise explicitly stated or limited, the terms "disposed" and "connected" are to be interpreted broadly, and for example, "connected" may be a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; the connection may be direct or indirect via an intermediate medium, and may be a communication between the two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The following detailed description of embodiments of the invention refers to the accompanying drawings.
As shown in fig. 1, the rope saw cutting device is used for permeability increasing and pressure relief of coal bed gas, and comprises a rope saw 1 for breaking coal bodies 6 and an adjusting piece for changing the relative position between a saw rope 2 and the coal bodies 6 in the rope saw 1, wherein a drill hole for penetrating the saw rope 2 is distributed in a coal bed gas pressure relief permeability increasing area, during pressure relief, a first end of the saw rope 2 penetrates through the drill hole to be fixedly connected with a second end of the saw rope 2, and the saw rope 2 cuts and breaks the coal bodies 6 above the pressure relief area.
The seam range of the coal body 6 above the sawing rope 2 seam cutting pressure relief area is 3-10 cm, a plurality of saw teeth are arranged on the sawing rope 2, and the distance between every two adjacent saw teeth ranges from 3 m to 5 m.
The adjusting part comprises at least two guide wheels 3 used for guiding the saw rope 2, moving parts used for moving the positions of the guide wheels 3 and a prop drawing winch 5, the moving action ends of the moving parts act on the guide wheels 3 respectively, the saw rope 2 is wound on the guide wheels 3, and the moving action ends of the prop drawing winch 5 act on the rope sawing machine 1.
The moving part comprises at least two 5t hand-operated hoists 4, and the moving action end of one 5t hand-operated hoist 4 acts on one guide wheel 3.
The coal bed gas permeability increasing and pressure relieving method comprises the following steps:
s1, setting a prediction drill hole and a test drill hole at a position 30cm away from a top plate above a coal seam controlled by a wire saw for carrying out a slotting experiment, wherein a slotting range is 3-10 cm, and determining the effective cutting drainage radius of the wire saw 1 by combining a flow method and a pressure method;
flow method: before cutting, measuring the gas flow of 1 drainage drilling hole every 5-10 minutes, and measuring more than 5 groups in total; in the slotting process, according to the change of the gas flow, measuring a group of gas flow every 5-10 minutes, after cutting, measuring more than 10 groups of data per shift, drawing a change curve of each drainage gas flow, and if the flow measured and recorded for 3 times is increased by 10% compared with the flow measured and recorded before cutting, indicating that the drainage drill hole is in the influence radius of the free surface to be cut; later, the sewing Guiyang is measured at least 3 times every day, and the condition of the increase and decrease of the drawing amount is examined.
Pressure method: recording the reading on the pressure gauge before cutting, observing the reading of the pressure gauge at the moment during cutting, measuring the gas pressure during cutting and after cutting, recording the pressure before cutting, reading, observing the change of the reading of the pressure gauge at the moment during cutting, and in the cutting process, if the reading of the pressure gauge has a descending trend, considering the distance as the effective cutting influence radius.
And S2, determining the density of the drainage drill hole according to the effective drainage radius formed after cutting, and distributing the hole drainage.
S3, as shown in figure 1, the sawing rope 2 of the rope sawing machine 1 passes through the drilled hole, the position of the hand-operated hoist 4 is moved, the rope saw is positioned by the guide wheel 3, the sawing rope 2 is enabled to be on the same inclined plane, and after the rope saw is installed, the movable pumping pump or the low negative pressure pump is startedThe pumping system starts the rope sawing machine 1 under the condition of empty load after starting the upper and lower high-pressure water heads, the coal body 6 is crushed and cut gradually at high speed, the sawing rope 2 of the rope sawing machine 2 runs at high speed for 15-40 m/s, the width of a cutting seam is controlled to be 3-10 cm, and the possibility of inducing protrusion is prevented; the running speed range of the sawing rope 2 in the whole pressure relief process is 10-40 m/s, the strength of the sawing rope 2 is 1700MPa, the diameter is 15.5 mm, the area is 56.52 square mm, the breaking tension is 56.53 multiplied by 1700 which is 95710N which is 9.57 (tons),
the conical saw teeth can not generate sparks when the coal body 6 is cut by collision in motion to achieve the effect of damaging the coal body 6, the cutting effect is very good in the position where the rock formation firmness coefficient f is less than 3, the sawing rope 2 is an endless steel wire rope, the first end and the second end of the sawing rope 2 are butted by adopting a braiding method, the braiding length is more than 15D, the braiding length is not less than 300mm, the strength is not less than 75 percent of the breaking force of the steel wire rope,
the arrangement density of the conical saw teeth is 3-5 m/per, the inclined length range of the working face is 50-60 m by adjusting according to the length of the cutting working face, the mode of cutting while retreating is carried out by adopting the prop withdrawing winch 5, and the running speed range of the saw rope 2 of the rope sawing machine 1 is 30-40 m/s when the prop withdrawing winch 5 moves.
The whole surface of the coal bed is damaged and cut, so that a large free space is formed in the coal body, the surrounding coal body moves, deforms and flows in the direction of the free space, the stress balance of the coal body is continuously and repeatedly broken, and finally the coal body is in a new stress balance state; sufficient space is provided for expansion deformation of coal bodies around the rope saw after the rope saw cuts a slot, the expansion deformation of the coal bodies keeps limited degree (3-10 cm control induces the possibility of protrusion), so more expansion deformation of the coal bodies causes opening and mutual permeability of pores and crack systems in the coal bodies, favorable conditions are provided for efficient gas desorption and high-speed flow, the original properties of the coal bodies are thoroughly changed by the slot, and the purpose of quickly eliminating the danger of protrusion of coal layer areas is achieved
The technical solution of the present invention is not limited to the limitations of the above specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention.
Claims (10)
1. Rope saw cutting device for the anti-reflection release of coal seam gas, its characterized in that: the coal seam gas pressure relief and permeability increasing area is provided with a drill hole for penetrating through the sawing rope, during pressure relief, the first end of the sawing rope penetrates through the drill hole and is fixedly connected with the second end of the sawing rope, and the sawing rope cuts a seam to break the coal body above the pressure relief area.
2. The rope saw cutting device of claim 1, wherein: the seam opening range of the coal body above the sawing rope seam cutting pressure relief area is 3-10 cm.
3. The rope saw cutting device of claim 1, wherein: the sawing rope is provided with a plurality of saw teeth.
4. The rope saw cutting device of claim 3, wherein: the distance between two adjacent sawteeth ranges from 3 m to 5 m.
5. Rope saw cutting device according to any one of claims 1-4, characterized in that: the adjusting part comprises at least two guide wheels used for guiding the sawing rope and a moving part used for moving the positions of the guide wheels, the moving action ends of the moving part respectively act on the guide wheels, and the sawing rope is wound on the guide wheels.
6. The rope saw cutting device of claim 5, wherein: the moving part comprises at least two hand-operated hoists, and the moving action end of one hand-operated hoist acts on one guide wheel.
7. The rope saw cutting device of claim 5, wherein: the adjusting part also comprises a prop pulling winch, and the moving action end of the prop pulling winch acts on the rope sawing machine.
8. The coal bed gas permeability increasing and pressure relieving method is characterized by comprising the following steps:
s1, determining the effective drainage radius of the rope saw after cutting;
s2, determining the drilling density and position of the gas to be drained according to the effective drainage radius of the cut seam, and drilling;
s3, cutting a seam on the whole coal seam by a sawing rope of the rope sawing machine, moving the position of a hand-operated block and positioning the position of a rope saw by a guide wheel, after the rope sawing machine is installed, starting a movable drainage pump or a low negative pressure drainage system, starting an upper high pressure water head and a lower high pressure water head, starting the rope sawing machine under the condition of no load, and crushing and cutting the coal body above a pressure relief area to generate a large number of new cracks on the coal body.
9. The method for increasing and relieving coal seam gas permeability and pressure according to claim 8, wherein in S1, a slotting experiment is performed at a position 30cm above the coal seam from the top plate, and the flow method and the pressure method are combined to determine the effective slotting drainage radius of the wire saw.
10. The coal seam gas permeability increasing and pressure relieving method according to claim 8 or 9, wherein in S3, the running speed of the sawing rope is 15-40 m/S, and the seam opening range of the coal body above the sawing rope seam cutting and pressure relieving area is 3-10 cm.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010944644.1A CN112145223A (en) | 2020-09-10 | 2020-09-10 | Rope saw cutting device and coal bed gas permeability increasing and pressure relieving method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010944644.1A CN112145223A (en) | 2020-09-10 | 2020-09-10 | Rope saw cutting device and coal bed gas permeability increasing and pressure relieving method |
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| CN112145223A true CN112145223A (en) | 2020-12-29 |
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| CN202010944644.1A Pending CN112145223A (en) | 2020-09-10 | 2020-09-10 | Rope saw cutting device and coal bed gas permeability increasing and pressure relieving method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113236348A (en) * | 2021-06-30 | 2021-08-10 | 平顶山市安泰华矿用安全设备制造有限公司 | Coal seam slit gas treatment outburst prevention process |
| CN113622912A (en) * | 2021-07-30 | 2021-11-09 | 平顶山市安泰华矿用安全设备制造有限公司 | Outburst eliminating process for coal seam mining |
| CN114233289A (en) * | 2021-12-21 | 2022-03-25 | 上海应用技术大学 | Chain saw cutting device and method for increasing permeability and pressure relief of coal seam gas |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102434153A (en) * | 2011-12-19 | 2012-05-02 | 重庆市能源投资集团科技有限责任公司 | Coal mining device and coal mining method for unmanned working face of steeply inclined extremely thin coal seam |
| CN104481529A (en) * | 2014-09-18 | 2015-04-01 | 哈尔滨银桥机械设备有限责任公司 | Rope-aligning mining device for thin seam ploughing and transportation |
| CN105401976A (en) * | 2015-12-30 | 2016-03-16 | 重庆南桐矿业有限责任公司 | Outburst prevention measure in wire saw joint-cutting region of coal seam floor |
| CN214660326U (en) * | 2020-09-10 | 2021-11-09 | 李章明 | Rope saw cutting device |
-
2020
- 2020-09-10 CN CN202010944644.1A patent/CN112145223A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102434153A (en) * | 2011-12-19 | 2012-05-02 | 重庆市能源投资集团科技有限责任公司 | Coal mining device and coal mining method for unmanned working face of steeply inclined extremely thin coal seam |
| CN104481529A (en) * | 2014-09-18 | 2015-04-01 | 哈尔滨银桥机械设备有限责任公司 | Rope-aligning mining device for thin seam ploughing and transportation |
| CN105401976A (en) * | 2015-12-30 | 2016-03-16 | 重庆南桐矿业有限责任公司 | Outburst prevention measure in wire saw joint-cutting region of coal seam floor |
| CN214660326U (en) * | 2020-09-10 | 2021-11-09 | 李章明 | Rope saw cutting device |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113236348A (en) * | 2021-06-30 | 2021-08-10 | 平顶山市安泰华矿用安全设备制造有限公司 | Coal seam slit gas treatment outburst prevention process |
| CN113622912A (en) * | 2021-07-30 | 2021-11-09 | 平顶山市安泰华矿用安全设备制造有限公司 | Outburst eliminating process for coal seam mining |
| CN113622912B (en) * | 2021-07-30 | 2024-03-12 | 平顶山市安泰华矿用安全设备制造有限公司 | Outburst elimination technology for coal mining |
| CN114233289A (en) * | 2021-12-21 | 2022-03-25 | 上海应用技术大学 | Chain saw cutting device and method for increasing permeability and pressure relief of coal seam gas |
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