CN113153299B - Microwave directional roof-cutting pressure-relief gob-side entry retaining method - Google Patents
Microwave directional roof-cutting pressure-relief gob-side entry retaining method Download PDFInfo
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- CN113153299B CN113153299B CN202110510840.2A CN202110510840A CN113153299B CN 113153299 B CN113153299 B CN 113153299B CN 202110510840 A CN202110510840 A CN 202110510840A CN 113153299 B CN113153299 B CN 113153299B
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- 238000000034 method Methods 0.000 title claims abstract description 41
- 238000005520 cutting process Methods 0.000 title claims abstract description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 62
- 239000012530 fluid Substances 0.000 claims abstract description 39
- 238000005553 drilling Methods 0.000 claims abstract description 30
- 239000003245 coal Substances 0.000 claims abstract description 14
- 238000007789 sealing Methods 0.000 claims abstract description 4
- 230000000149 penetrating effect Effects 0.000 claims abstract 2
- 238000002347 injection Methods 0.000 claims description 26
- 239000007924 injection Substances 0.000 claims description 26
- 239000003566 sealing material Substances 0.000 claims description 4
- 239000011435 rock Substances 0.000 abstract description 29
- 238000005065 mining Methods 0.000 abstract description 6
- 230000005855 radiation Effects 0.000 abstract description 6
- 230000008602 contraction Effects 0.000 abstract description 5
- 238000004880 explosion Methods 0.000 abstract description 3
- 238000005422 blasting Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000004227 thermal cracking Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000011083 cement mortar Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH 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
Abstract
The invention discloses a microwave directional roof-cutting pressure-relief gob-side entry retaining method, belongs to the field of coal mining, and aims to improve the safety coefficient of gob-side entry protection. Constructing a plurality of drill holes on the lower side of the return airway; grouping the drill holes according to a group of at least 3 adjacent drill holes; selecting one group of drilling holes; microwave transmitters for aligning the middle holes are respectively arranged in the left side hole and the right side hole of the microwave oven; sealing the middle hole and filling water into the middle hole; opening the microwave emitter until the water temperature is greater than or equal to 50 ℃, and closing the microwave emitter; injecting low-temperature fluid into the middle hole to enable water in the middle hole to be condensed into ice; after the other groups of drilling and roof cutting operations are completed, a penetrating pre-splitting joint is formed on the overlying strata of the return air roadway. In the whole process, the rock is heated and broken under the action of microwave radiation, and the expansion of cracks is caused by the expansion of the rock due to heat expansion and contraction of the rock and the volume increase in the process of changing water into ice, so that the whole process is not required to operate in a high-pressure state, the safety is high, the explosion is not required, and the method is well applicable to high-gas mines and protruding mines.
Description
Technical Field
The invention belongs to the field of coal mining, and particularly relates to a microwave directional roof-cutting pressure-relief gob-side entry retaining method and device.
Background
Along with the continuous increase of the mining depth of the coal mine, the mining intensity is continuously increased, the disasters of the coal mine are also increasingly serious, and the disaster treatment time is continuously prolonged, so that the situation of the shortage of mining succession of the coal mine is caused. In order to alleviate this situation, most mines employ gob-side entry retaining techniques. However, along with the pushing of the working face, the situations of large deformation of surrounding rock of the roadway, difficult roof support and the like can occur when the gob-side entry retaining is adopted, and particularly, when the periodic initial pressure step distance is large, large-area suspended roof and large stress concentration phenomenon can occur in the goaf, so that mining pressure disasters such as roof fall of the roadway, anchor rod and anchor cable fracture and the like are caused.
At present, a roof-cutting pressure relief technology is generally adopted for gob-side entry protection in mines, and the main modes are a drilling blasting method and a hydraulic fracturing method, but the explosive for drilling blasting is difficult to manage and approve, the transportation and storage processes are controlled, the explosive quantity is difficult to control during blasting, and the CO overrun alarm of a T2 probe of a return airway is easy to cause; the fracturing range is difficult to control when the hydraulic fracturing method is used for roof cutting and pressure relief, the operation difficulty is high, safety problems are easy to occur, and the whole fracturing equipment and the roadway roof are in a high-pressure state for a long time, so that the safe and efficient production of a mine is severely restricted.
Disclosure of Invention
The invention aims to solve the problem of high potential safety hazard in gob-side entry protection by roof cutting and pressure relief at present, and provides a microwave directional roof cutting and pressure relief gob-side entry retaining method for improving the safety coefficient of gob-side entry protection.
The technical scheme adopted by the invention is as follows: a microwave directional roof-cutting pressure-relief gob-side entry retaining method,
Step 1, constructing a plurality of drilling holes along the extending direction of a return air roadway on the lower side of the return air roadway; and each drilling end penetrates through the coal seam roof to collapse the key layer, the drilling holes are grouped according to at least 3 adjacent drilling holes as a group, and the drilling holes in each group respectively comprise a middle hole, a left hole positioned at the left side of the middle hole and a right hole positioned at the right side of the middle hole;
step 2, selecting one group of drilling holes, and respectively installing microwave transmitters with focusing functions in the left hole and the right hole of the drilling holes; connecting a microwave emitter with a microwave generator by using a waveguide wire; the microwave emitter is aligned with the middle hole; sealing the middle hole by using a hole sealing material;
Step 3, filling water into the middle hole;
Step 4, turning on the microwave generator until the water temperature is greater than or equal to 50 ℃, and turning off the microwave generator;
Step 5, injecting low-temperature fluid into the middle hole to enable water in the middle hole to be condensed into ice;
And 6, repeating the steps 2 to 5 to finish the operations of drilling and roof cutting of other groups, and forming a through pre-splitting joint on the overlying strata of the return air roadway.
Further, the hydraulic single prop is used for supporting the top plate in the return airway.
Further, in each group, the interval between two adjacent drilling holes is 0.5m-2m, and the number of the drilling holes in each group is equal to 3.
Further, a microwave emitter is mounted at the critical layer.
Further, a microwave focusing device is installed on the microwave emitter.
Further, the heat pipe is communicated with the middle hole through a low temperature resistant pipe;
Injecting water into the middle hole by adopting a water injection device; the water injection device comprises a water injection pump, and the water injection pump is connected with the low temperature resistant Guan Xiang through a water injection pipeline.
Further, a low-temperature fluid injection device is adopted to inject low-temperature fluid into the middle hole; the low-temperature fluid injection device comprises a low-temperature fluid tank and a low-temperature fluid pump, wherein the low-temperature fluid tank is connected with the low-temperature resistant Guan Xiang through a fluid pipeline provided with the low-temperature fluid pump.
Further, a temperature display for displaying the water temperature in the middle hole and a pressure gauge for displaying the water pressure in the middle hole are arranged.
The beneficial effects of the invention are as follows: according to the microwave directional roof-cutting pressure-relief gob-side entry retaining method disclosed by the invention, after a microwave emitter radiates a roof stratum of a return air roadway, the local rock is subjected to directional heating to generate radial thermal cracking; meanwhile, the water in the middle hole is heated and heated, after the low-temperature fluid is injected into the middle hole, the hot water meets the low-temperature fluid, the water in the middle hole is quickly condensed into ice, surrounding rocks are cooled, continuous cracks appear on the rocks due to the effect of thermal expansion and cold contraction, and the volume expansion of the rocks is 9% -10% in the process of condensing the water into ice, so that the cracks of the rocks expand the rocks again, and continuous pre-splitting cutting joints appear on the top plate of the return air lane. When the stope face is pushed to the pre-splitting joint, roof rock can be sheared and broken in time under the action of mine pressure and dead weight, and stress concentration phenomenon of a roadway is prevented, so that the problem of difficulty in supporting the roadway is solved.
The method adopts the microwave directional radiation mode, so that the heating direction and the position of the rock can be ensured, the roof cutting angle and the roof cutting direction of the pre-cracking joint can be controlled, and the operation is easy.
In the whole process, the rock is heated and broken under the action of microwave radiation, the expansion of cracks is completed under the action of volume increase in the process of expanding with heat and contracting with cold of the rock and changing water into ice, the whole process is not required to operate in a high-pressure state, the safety is high, the explosion is not required, and the method is well applicable to high-gas mines and protruding mines.
Drawings
FIG. 1 is a schematic diagram of the overall arrangement of the present invention;
FIG. 2 is a schematic diagram of a microwave directional roof-cutting and pressure relief operation according to the present invention.
In the figure, a left hole 1-1, a right hole 1-2, a middle hole 1-3, a microwave focusing device 2, a microwave emitter 3, a waveguide wire 4, a microwave generator 5, a low-temperature fluid pump 6, a low-temperature fluid tank 7, a water injection pump 8, a temperature display 9, a pressure gauge 10, a direct top layer 11, a key layer 12, a pre-splitting joint 13, a hydraulic single prop 14, a return air lane 15, a transportation lane 16, a stope face 17 and a coal seam 19.
Detailed Description
The invention is further illustrated in the following figures and examples, in which:
A microwave directional roof-cutting pressure-relief gob-side entry retaining method,
Step 1, as shown in fig. 1 and fig. 2, in step 1, a plurality of drill holes are constructed along the extending direction of the return air roadway 15 on the lower side of the return air roadway 15; and each drilling end penetrates through the roof of the coal seam to collapse the key layer 12, the drilling holes are grouped according to a group of at least 3 adjacent drilling holes, and the drilling holes in each group respectively comprise a middle hole 1-3, a left hole 1-1 positioned at the left side of the middle hole 1-3 and a right hole 1-2 positioned at the right side of the middle hole 1-3;
step 2, selecting one group of drilling holes, and respectively installing microwave transmitters 3 with focusing functions in the left hole 1-1 and the right hole 1-2 of the drilling holes; connecting the microwave emitter 3 with a microwave generator 5 by means of a waveguide wire 4; the microwave emitter 3 is aligned with the middle hole 1-3; sealing the middle hole 1-3 by using a hole sealing material;
Step 3, filling water into the middle hole 1-3;
Step 4, turning on the microwave generator 5 until the water temperature is greater than or equal to 50 ℃, and turning off the microwave generator 5;
step 5, injecting low-temperature fluid into the middle hole 1-3 to condense water in the middle hole 1-3 into ice;
And 6, repeating the steps 2 to 5 to finish the operations of drilling and roof cutting of other groups, and forming a through pre-splitting joint 13 on the overlying strata of the return air duct 15.
In the step 2, the hole sealing material may be cement mortar or the like. In the step 3, the water is filled in the middle hole 1-3 so as to ensure that the volume expansion of the water in the middle hole 1-3 can squeeze the rock after the water is condensed into ice. In step 5, the cryogenic fluid may be liquid nitrogen, liquid carbon dioxide, or the like, which is a fluid capable of rapidly condensing water into ice.
According to the microwave directional roof-cutting pressure-relief gob-side entry retaining method disclosed by the invention, after a microwave emitter 3 radiates a roof rock stratum of a return air lane 15, the local rock is subjected to directional heating to generate radial thermal cracking; meanwhile, the rock stratum is heated to transfer heat to water in the middle hole 1-3, the water is heated to rise temperature, after low-temperature fluid is injected into the middle hole 1-3, the hot water meets the low-temperature fluid, the water in the middle hole 1-3 is quickly condensed into ice, surrounding rocks are cooled, continuous cracks appear on the rocks due to the effect of thermal expansion and cold contraction, and the volume expansion is 9% -10% in the process of the water condensing into ice, so that the cracks of the rocks expand the rocks again, and continuous pre-splitting slits 13 appear on the top plate of the return air lane 15. When the stope face 17 is pushed to the pre-splitting joint 13, roof rock can be sheared and broken in time under the action of mine pressure and dead weight, the rock stratum of a goaf collapses, the problem of large-area suspended roof can be avoided, the phenomenon of stress concentration of a roadway is prevented, and therefore the problem of difficulty in roadway support is solved.
The microwave directional radiation mode can ensure the heated direction and position of the rock, so that the roof cutting angle and the roof cutting direction of the pre-splitting joint 13 are controllable, and the operation is easy.
In the whole process, the rock is heated and broken under the action of microwave radiation, the expansion of the crack is completed under the action of the expansion of the rock with heat and contraction of cold and the volume increase in the process of changing water into ice, the whole process is not required to operate in a high-pressure state, the safety is high, the explosion is not required, and the method is well applicable to high-gas mines and protruding mines.
Wherein, the lower side of the return air lane 15 is the side of the return air lane 15 adjacent to the transportation lane 16.
Each drill hole end penetrates the roof of the coal seam to collapse the key layer 12, which means that the drill hole penetrates the direct top layer 11 to extend to the key layer 12. The direct top layer 11 and the key layer 12 are overburden layers on top of the coal seam. The key layer 12 is further from the coal seam 19 than the direct top layer 11.
In order to ensure safety, the roof is supported by hydraulic single struts 14 in the return air duct 15.
In order to improve the controllability of the topping angle and the topping direction and to improve the topping efficiency, it is preferable that the pitch of each set of holes is 0.5m-2m, and the number of holes in each set is equal to 3. The hole spacing is controlled within the range of 0.5m-2m, so that the acting force of water expansion and contraction in the middle hole 1-3 can be ensured to cover the left hole 1-1 and the right hole 1-2; it is also ensured that microwaves can penetrate the rock formation between adjacent boreholes. The number of the drill holes is controlled to be 3, so that energy waste is avoided, and the risk of no crack between the drill holes among groups is avoided.
Since whether the roof of the coal seam collapses in rock mechanics has a direct relation to the critical layer 12, in order to enable the microwave emitter 3 to illuminate the critical layer as much as possible, it is preferred that the microwave emitter 3 is mounted at the critical layer 12. The coal seam 19 is shown in fig. 1.
In order to play a role in wave focusing, microwaves emitted by the microwave emitter 3 form parallel microwaves with a certain width, directional radiation is ensured, and the microwave focusing device 2 is arranged on the microwave emitter 3.
The water injection device and the cryogenic fluid injection device can extend into the middle hole 1-3 through independent pipelines, but the pipeline waste is caused, the pipeline laying engineering amount is increased, and in order to avoid the problem, the water injection device and the cryogenic fluid injection device are communicated with the middle hole 1-3 through a low-temperature resistant pipe; injecting water into the middle hole 1-3 by adopting a water injection device; the water injection device comprises a water injection pump 8, and the water injection pump 8 is connected with the low temperature resistant Guan Xiang through a water injection pipeline. Injecting low-temperature fluid into the middle hole 1-3 by adopting a low-temperature fluid injection device; the cryogenic fluid injection device comprises a cryogenic fluid tank 7 and a cryogenic fluid pump 6, wherein the cryogenic fluid tank 7 is connected with a cryogenic fluid Guan Xiang through a fluid pipeline provided with the cryogenic fluid pump 6.
And is provided with a temperature display 9 for displaying the water temperature in the intermediate hole 1-3 and a pressure gauge 10 for displaying the water pressure in the intermediate hole 1-3.
The pressure gauge 10 monitors the water pressure in the middle hole 1-3, namely the pressure of the water on the inner hole wall of the middle hole 1-3, so as to judge whether the middle hole 1-3 is filled with water. If the pressure gauge 10 shows a water pressure value greater than or equal to 0.1Mpa, it is determined that the inside of the intermediate hole 1-3 is full of water. The temperature display 9 monitors the water temperature and indicates the opening and closing of the microwave generator 5.
Claims (8)
1. The microwave directional roof-cutting pressure-relief gob-side entry retaining method is characterized in that:
Step1, constructing a plurality of drill holes along the extending direction of a return airway (15) on the lower side of the return airway (15); and each drilling end penetrates through a coal seam roof to collapse a key layer (12), the drilling holes are grouped according to a group of at least 3 adjacent drilling holes, and the drilling holes in each group respectively comprise a middle hole (1-3), a left hole (1-1) positioned at the left side of the middle hole (1-3) and a right hole (1-2) positioned at the right side of the middle hole (1-3);
Step 2, selecting one group of drilling holes, and respectively installing microwave transmitters (3) with focusing functions in the left hole (1-1) and the right hole (1-2) of the drilling holes; connecting the microwave emitter (3) with the microwave generator (5) by using a waveguide wire (4); the microwave emitter (3) is aligned with the middle hole (1-3); sealing the middle hole (1-3) by using a hole sealing material;
step 3, filling water into the middle hole (1-3);
Step 4, turning on the microwave generator (5), radiating a roof stratum of the return airway (15) through the microwave emitter (3), and turning off the microwave generator (5) until the water temperature is greater than or equal to 50 ℃;
step 5, injecting low-temperature fluid into the middle hole (1-3) to condense water in the middle hole (1-3) into ice;
And 6, repeating the steps 2 to 5 to finish other groups of drilling and roof cutting operations, and forming a penetrating pre-splitting joint (13) on the overlying strata of the return air gallery (15).
2. The microwave directional roof-cutting pressure-relief gob-side entry retaining method of claim 1, wherein the method comprises the following steps: the top plate is supported by the hydraulic single prop (14) in the air return tunnel (15).
3. The microwave directional roof-cutting pressure-relief gob-side entry retaining method according to claim 1 or 2, characterized in that: in each group, the interval between two adjacent drilling holes is 0.5m-2m, and the number of the drilling holes in each group is equal to 3.
4. The microwave directional roof-cutting pressure-relief gob-side entry retaining method according to claim 1 or 2, characterized in that: the microwave emitter (3) is mounted on the critical layer (12).
5. The microwave directional roof-cutting pressure-relief gob-side entry retaining method of claim 4, wherein the method comprises the following steps: a microwave focusing device (2) is arranged on the microwave emitter (3).
6. The microwave directional roof-cutting pressure-relief gob-side entry retaining method according to claim 1 or 2, characterized in that: is communicated with the middle hole (1-3) through a low temperature resistant pipe;
Water is injected into the middle hole (1-3) by adopting a water injection device; the water injection device comprises a water injection pump (8), and the water injection pump (8) is connected with the low temperature resistant Guan Xiang through a water injection pipeline.
7. The microwave directional roof-cutting pressure-relief gob-side entry retaining method of claim 6, wherein the method comprises the following steps: injecting low-temperature fluid into the middle hole (1-3) by adopting a low-temperature fluid injection device; the low-temperature fluid injection device comprises a low-temperature fluid tank (7) and a low-temperature fluid pump (6), wherein the low-temperature fluid tank (7) is connected with the low-temperature resistant Guan Xiang through a fluid pipeline provided with the low-temperature fluid pump (6).
8. The microwave directional roof-cutting pressure-relief gob-side entry retaining method of claim 7, wherein the method comprises the following steps: and is provided with a temperature display (9) for displaying the water temperature in the middle hole (1-3) and a pressure gauge (10) for displaying the water pressure in the middle hole (1-3).
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| CN202110510840.2A CN113153299B (en) | 2021-05-11 | 2021-05-11 | Microwave directional roof-cutting pressure-relief gob-side entry retaining method |
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| CN113622917A (en) * | 2021-07-26 | 2021-11-09 | 中南大学 | Deep high-stress tunnel surrounding rock microwave pressure relief method |
| CN114198100B (en) * | 2021-12-03 | 2023-06-20 | 太原理工大学 | Rock drilling high-temperature thermal cracking axial directional pre-cracking equipment |
| CN114810005B (en) * | 2022-05-19 | 2022-12-23 | 贵州大学 | Coal seam fracturing method under coal roadway horizontal joint cutting-carbon dioxide blasting synergistic effect |
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| CN111022049A (en) * | 2019-11-25 | 2020-04-17 | 中国矿业大学 | Operation-controllable roof-cutting pressure-relief gob-side entry retaining method |
| CN111287702A (en) * | 2020-02-20 | 2020-06-16 | 中国矿业大学 | Coal bed permeability increasing method with ice particle abrasive jet flow slotting and microwave heat injection in cooperation |
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| WO2016150188A1 (en) * | 2015-03-25 | 2016-09-29 | 中国矿业大学 | Method for fracturing filler wall left behind in adjacent coal-mining face |
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