Method for fracturing top coal by using static expanding agent and drilling and grouting equipment

Abstract

The invention provides a method for fracturing top coal through a static expanding agent and drilling and pouring equipment, in the scheme, the daily mining length of a fully mechanized caving face in the extending direction of the fully mechanized caving face is preset to be L / N, N sets of holes are drilled according to the daily mining length, and the length of the drilled holes in the extending direction of the fully mechanized caving face is L, the distance between every two adjacent drill holes in each group of drill holes is ND, and after construction of all the N groups of drill holes is completed, the distance between any two adjacent drill holes in the width direction of the top coal is D. The N groups of drill holes are sequentially constructed in front of the current mining area on different working days, and the N groups of drill holes are distributed in a staggered manner, so that the mining efficiency is improved. Through the operation of pouring the static expanding agent into the drill hole and blocking, the top coal generates a gradually-increased crack in the expansion process, a free surface can be reserved for the top coal above after the mining equipment is pushed forwards, and the top coal at the position can be more accurately controlled to crack due to breaking and falling of the generated crack.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine mining, in particular to a method for cracking top coal using a static expansion agent and drilling and pouring equipment. Background Art

[0002] Coal mined from underground thick coal seams in my country accounts for about 40% of the country's coal production, and fully mechanized top coal caving mining technology plays an important role in this process. In the initial top coal caving mining process, most mines did not use any measures, and the top coal collapsed naturally under the pressure of the mine and the repeated support of the support; in order to improve the top coal crushing effect and increase the top coal recovery rate, some mines made improvements on this basis, using coal seam water injection, deep hole blasting, hydraulic fracturing or supercritical carbon dioxide phase change crushing to carry out top coal mining, but these improvements still have certain shortcomings. Deep hole blasting is too dangerous, and the storage, transportation and approval of explosives are inconvenient. In addition, deep hole blasting with explosives produces open flames and smoke, which is not conducive to underground construction safety; high-pressure hydraulic cutting requires larger equipment, low construction efficiency, and mutual interference with production; the supercritical carbon dioxide phase change crushing method is too inconvenient for the storage, transportation and application of carbon dioxide, and there are dangers such as excessive carbon dioxide content, which affects the safety of underground coal mine production. On this basis, top coal mining technology has made further progress and improvement. More and more mines use the method of injecting static expansion agent into the roof of the fully-mechanized caving face to crack the top coal to mine the top coal.

[0003] The prior art method of using a static expansion agent to crack top coal requires that drilling work and mining work by a coal mining machine be performed separately, which results in high time cost and low mining efficiency. Summary of the invention

[0004] The invention provides a method for cracking top coal using a static expansion agent and drilling and injection equipment, so as to solve the problem of affecting production efficiency in the process of mining top coal in the prior art.

[0005] In order to solve the above problems, according to one aspect of the present invention, a method for cracking top coal using a static expansion agent is provided, and the method for cracking top coal using a static expansion agent comprises:

[0006] The daily mining length of the fully-mechanized caving working face along its own extension direction is set as L / N, a hole is drilled on the top coal of the fully-mechanized caving working face, the length of the hole along the extension direction of the fully-mechanized caving working face is L, a static expansion agent is poured into the hole and the hole mouth of the hole is blocked, and the top coal generates gradually enlarging cracks during the expansion process of the static expansion agent; wherein,

[0007] The plurality of boreholes are divided into a first group of boreholes to an Nth group of boreholes, the distance between two adjacent boreholes in each group of boreholes is ND, the plurality of groups of boreholes are sequentially constructed on different production days, the plurality of groups of boreholes are staggered in the width direction and the extension direction of the top coal, and each group of boreholes is constructed in the upper front of the currently advanced mining area; wherein, the first group of boreholes is constructed on the first day, static expansion agents are poured and the boreholes are blocked, until the Nth group of boreholes is constructed on the Nth day, static expansion agents are poured and the boreholes are blocked, and after the construction of the Nth group of boreholes is completed, the distance between any two adjacent boreholes in the width direction of the top coal is D;

[0008] As coal mining progresses, the operations of drilling, injecting static expansion agents and sealing from the first group of holes to the Nth group of holes are cyclically performed in the advancing direction; wherein, after the coal mining machine and hydraulic support in the comprehensive caving working face are pushed forward, a free surface is left for the top coal originally located above the hydraulic support, and the top coal here is broken and falls due to the generated cracks.

[0009] Furthermore, the drilling, injection of static expansion agent and plugging operations are performed during the maintenance time of the production day.

[0010] In one embodiment, the daily mining length of the fully mechanized caving working face along its own extension direction is L / 3, and the multiple boreholes are divided into a first group of boreholes, a second group of boreholes and a third group of boreholes, and the distance between two adjacent boreholes in each group of boreholes is 3D.

[0011] Furthermore, the static expansion agent is a powdered inorganic material, which expands after mixing with water; after the static expansion agent is mixed with water, it begins to generate expansion force in 1 to 2 hours and reaches the maximum expansion force in 11 to 13 hours.

[0012] Furthermore, the drilling equipment used for drilling is installed on the scraper conveyor in the comprehensive caving working face, and the installation position on the scraper conveyor is adjustable. The drill bit in the drilling equipment is driven by a hydraulic motor, and the power source of the hydraulic motor is the emulsion pump station in the comprehensive caving working face.

[0013] According to another aspect of the present invention, a drilling and grouting device is provided, wherein the drilling and grouting device adopts the above-mentioned method of cracking top coal with a static expansion agent, and the drilling and grouting device comprises:

[0014] A drilling device, wherein the position of the drilling device is adjustably mounted on a scraper conveyor in a fully mechanized caving working face, the drilling device comprises a drill bit and a hydraulic motor, the hydraulic motor drives the drill bit to rotate, and the power source of the hydraulic motor is an emulsion pump station in the fully mechanized caving working face;

[0015] A hole sealer, the hole sealer comprising an elastic tube and a hole plug arranged at one end of the elastic tube, the elastic tube is used to penetrate into the top coal borehole and contain the injected static expansion agent, and the hole plug is used to seal the hole of the borehole;

[0016] The grouting and stirring integrated machine is used to stir the static expansion agent added with water, and input the stirred static expansion agent into the elastic cylinder.

[0017] Furthermore, the drilling equipment also includes a base, a supporting column, a drill support, a propulsion hydraulic cylinder and a sliding seat, the base is installed on the trough side of the scraper conveyor, the supporting column is liftably arranged on the base, the drill support is installed on the supporting column, the propulsion hydraulic cylinder is fixedly installed on the drill support, the sliding seat is slidably installed on the drill support, the hydraulic motor is installed on the sliding seat, and the propulsion hydraulic cylinder is used to push the sliding seat to move in the drilling direction.

[0018] Furthermore, the drilling equipment also includes a rotating disk, a rotating seat and an auxiliary column, the rotating disk is arranged between the base and the lower end of the supporting column, the rotating disk is used to drive the supporting column to rotate along its own axis, the rotating seat is arranged between the upper end of the supporting column and the drilling rig support, the rotating seat is used to drive the drilling rig support to swing along a horizontal axis, the auxiliary column is adjustably installed in the cable trough of the scraper conveyor, the auxiliary column can be raised and lowered, and the upper end of the auxiliary column can detachably contact the drilling rig support to support the drilling rig support.

[0019] Furthermore, the hole sealer also includes an exhaust pipe and a grouting pipe, both of which penetrate into the elastic tube from the hole plug, the length of the exhaust pipe penetrating into the elastic tube is greater than the length of the grouting pipe penetrating into the elastic tube, and the grouting pipe is connected to the grouting and mixing machine through a detachable pipeline.

[0020] Furthermore, the grouting and mixing machine includes a mixing tank, a rotary motor, a mixing blade and a grouting pump. The mixing tank is used to contain the static expansion agent and water. The rotary motor is installed on the top of the mixing tank. The rotary motor drives the mixing blade to rotate for mixing. The grouting pump is used to transport the static expansion agent after mixing into the elastic cylinder.

[0021] In this scheme, the daily mining length of the fully mechanized caving working face along its own extension direction is pre-set as L / N, and holes are drilled on the top coal of the fully mechanized caving working face according to the daily mining length. A total of N groups are drilled, and each group of holes has multiple holes. The distance between two adjacent holes is ND. After all the N groups of holes are completed, the distance between any two adjacent holes in the width direction of the top coal is D. N groups of holes are constructed in front of the mining area of ​​the current advancement area on different working days, and the N groups of holes are staggered in the width direction and extension direction of the top coal. In this way, the stress of the top coal can be distributed more evenly, the stress concentration area can be reduced, and the local instantaneous crushing and falling of the top coal can be avoided. In addition, the drilling work can be carried out simultaneously with the current mining area, saving time and improving mining efficiency. Moreover, in this scheme, by injecting a static expansion agent mixed with water into the borehole and performing a sealing operation, a free surface can be left for the top coal originally located above the hydraulic support after the coal mining machine and the hydraulic support are pushed forward. The top coal here is broken and falls due to the cracks generated, and the cracking of the top coal can be more accurately controlled, reducing damage to non-target areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 A flow chart showing a method for cracking top coal using a static expansion agent provided by the present invention is shown;

[0024] Figure 2 A schematic diagram showing the positions of the first group of drill holes in a cycle in an embodiment provided by the present invention is shown;

[0025] Figure 3 A schematic diagram showing the positions of the second group of boreholes in one cycle in an embodiment provided by the present invention is shown;

[0026] Figure 4 A schematic diagram showing the positions of the third group of boreholes in one cycle in an embodiment provided by the present invention is shown;

[0027] Figure 5 A complete schematic diagram of a cycle in an embodiment provided by the present invention is shown;

[0028] Figure 6 A top view of a first group of holes drilled in one cycle in an embodiment provided by the present invention is shown;

[0029] Figure 7 A top view of a second group of boreholes in one cycle of an embodiment provided by the present invention is shown;

[0030] Figure 8 A top view of a third group of boreholes in one cycle in an embodiment provided by the present invention is shown;

[0031] Fig. 9 A complete top view of a cycle in an embodiment provided by the present invention is shown;

[0032] Fig.10 A schematic structural diagram of a drilling and injection equipment provided by the present invention is shown;

[0033] Fig.11 A schematic structural diagram of a hole sealer in an embodiment of the present invention is shown;

[0034] Fig.12 A schematic diagram of the structure of a grouting and mixing integrated machine in an embodiment provided by the present invention is shown;

[0035] Fig.13 A schematic diagram of the expansion of a static expansion agent in an embodiment provided by the present invention is shown;

[0036] Fig.14 A schematic diagram of a top coal fissure in an embodiment provided by the present invention is shown.

[0037] The above drawings include the following reference numerals:

[0038] 1. Drill bit; 2. Hydraulic motor; 3. Propulsion hydraulic cylinder; 4. Drilling rig support; 5. Base; 6. Rotating disk; 7. Support column; 8. Rotating seat; 9. Auxiliary column; 10. Water inlet; 11. Liquid inlet; 12. Liquid outlet; 13. Channel side; 14. Cable trough; 15. Fastening screw; 16. Orifice plug; 17. Exhaust pipe; 18. Grouting pipe; 19. Elastic cylinder; 20. Rotating motor; 21. Emulsion pressurization port; 22. Discharge port; 23. Agitator; 24. Grouting pump; 25. Grouting port; 26. Static expansion agent; 27. Sliding seat; 28. Top coal; 29. ​​Hydraulic support; 30. Scraper conveyor; 31. The first group of drill holes; 32. The second group of drill holes; 33. The third group of drill holes; 34. Transport lane; 35. Return air lane; 36. Coal mining face. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] like Figures 1 to 9 As shown, an embodiment of the present invention provides a method for cracking top coal 28 with a static expansion agent 26, and the method for cracking top coal 28 with a static expansion agent 26 includes:

[0041] The daily mining length of the fully mechanized caving working face along its own extension direction is set to L / N, a hole is drilled on the top coal 28 of the fully mechanized caving working face, and the length of the hole along the extension direction of the fully mechanized caving working face is L. A static expansion agent 26 is poured into the hole and the hole mouth is blocked. The top coal 28 generates gradually increasing cracks during the expansion process of the static expansion agent 26; wherein,

[0042] The multiple boreholes are divided into a first group of boreholes 31 to an Nth group of boreholes, the distance between two adjacent boreholes in each group of boreholes is ND, the multiple groups of boreholes are sequentially constructed on different production days, the multiple groups of boreholes are staggered in the width direction and the extension direction of the top coal 28, and each group of boreholes is constructed in the upper front of the currently advanced mining area; wherein, the first group of boreholes is constructed on the first day, the static expansion agent 26 is poured and the boreholes are blocked, until the Nth group of boreholes is constructed on the Nth day, the static expansion agent 26 is poured and the boreholes are blocked, and after the construction of the Nth group of boreholes is completed, the distance between any two adjacent boreholes in the width direction of the top coal 28 is D;

[0043] As coal mining progresses, drilling, injection of static expansion agent 26 and sealing operations from the first group of holes to the Nth group of holes are cyclically performed in the advancing direction; among them, after the coal mining machine and hydraulic support 29 in the comprehensive caving working face are pushed forward, a free surface is left for the top coal 28 originally located above the hydraulic support 29, and the top coal 28 here is broken and falls due to the generated cracks.

[0044] In this embodiment, by presetting the daily mining length of the fully mechanized caving working face along its own extension direction as L / N, drilling is performed on the top coal of the fully mechanized caving working face according to the daily mining length, and a total of N groups are drilled, each group of boreholes has multiple boreholes, and the distance between two adjacent boreholes is ND. After all the N groups of boreholes are completed, the distance between any two adjacent boreholes in the width direction of the top coal 28 is D. The N groups of boreholes are constructed in front of the mining area of ​​the current advancement area in sequence on different working days, and the N groups of boreholes are staggered in the width direction and extension direction of the top coal 28. In this way, the stress of the top coal 28 can be distributed more evenly, the stress concentration area can be reduced, and the local instantaneous crushing and falling of the top coal 28 can be avoided. In addition, the drilling work can be carried out simultaneously with the current mining area, saving time and improving mining efficiency. Moreover, in this embodiment, by injecting the static expansion agent 26 mixed with water into the borehole and performing the plugging operation, a free surface can be reserved for the top coal 28 originally located above the hydraulic support 29 after the coal mining machine and the hydraulic support 29 are pushed forward. The top coal 28 here is broken and falls due to the cracks generated, and the fracturing of the top coal 28 can be more accurately controlled to reduce the damage to non-target areas. In this embodiment, a transport lane 34 and a return air lane 35 are also included. The transport lane 34 is used to transport the broken and cracked top coal, and the return air lane 35 is a lane used by the mine to guide the airflow of the return air.

[0045] In this embodiment, the drilling holes are divided into a first group of drilling holes 31, a second group of drilling holes 32 and a third group of drilling holes 33. Multiple drilling machines can be arranged on the coal mining face 36 to perform construction at the same time, thereby increasing construction efficiency. The first group of drilling holes 31 is constructed during the first day of the maintenance shift, and the first group of drilling holes 31 is spaced 3D apart (since the second group of drilling holes 32 and the third group of drilling holes 33 have not been constructed, a drilling hole spacing D is reserved in advance); Figure 3 and Figure 7 As shown, the second group of boreholes 32 are constructed in the second day maintenance shift, and the first group of boreholes 31 are constructed at the same side of the interval D. Since the daily mining length of the working face is L / 3, the projection of the first group of boreholes 31 is only 2L / 3 long; Figure 4 and Figure 8 As shown, the third group of boreholes 33 are constructed at a distance D between the first group of boreholes 31 and the second group of boreholes 32. Due to the daily mining length of the working face, the first group of boreholes 31 has a length of L / 3, and the second group of boreholes 32 has a length of 2L / 3. At this time, in the next daily cycle of the working face, the first, second and third groups of boreholes with a spacing of D are filled in the coal mining working face, as shown in FIG. Figure 8 As shown; when the next coal mining face has mined L / 3 of the daily cycle, the first group of boreholes 31 disappears, and the second group of boreholes 32 project a length of L / 3, and a drilling construction cycle is completed. When the next day's maintenance team arrives, drilling is performed again at the position of the first group of boreholes 31, as shown in FIG. Fig. 9As shown. This ensures that after three maintenance teams have drilled holes, the subsequent fully mechanized caving working face can ensure that there are holes with a spacing of D each time when caving top coal 28. It can also achieve dynamic adjustment between the number of drilling groups, the spacing between drilling holes and the horizontal projection length of the holes, meeting the needs of most fully mechanized caving working faces.

[0046] The drilling, injection of static expansion agent 26 and plugging operations are performed during the maintenance time of the production day. In this embodiment, the drilling, injection of static expansion agent 26 mixed with water and plugging can be performed during the maintenance time of the production day, so that these operations do not need to be performed after the mining is completed, which saves a lot of time and can improve the efficiency of mining.

[0047] Furthermore, the daily mining length of the fully mechanized caving working face along its own extension direction is L / 3, and the multiple boreholes are divided into a first group of boreholes 31, a second group of boreholes 32 and a third group of boreholes 33, and the distance between two adjacent boreholes in each group of boreholes is 3D. In this embodiment, by grouping the boreholes and controlling the borehole spacing, the borehole layout and mining plan can be adjusted according to the actual mining conditions and geological conditions, which has a certain degree of flexibility, and can also better control the stability of the mining process and reduce the risk of mine accidents.

[0048] Further, the static expansion agent 26 is a powdered inorganic material, which expands after mixing with water; after the static expansion agent 26 is mixed with water, it begins to generate expansion force in 1 to 2 hours, and reaches the maximum expansion force in 11 to 13 hours. In the present embodiment, the static expansion agent 26 is a gray-white powdered inorganic material, which expands after mixing with water, generates a slowly increasing expansion stress, and achieves the purpose of static cracking of coal and rock. The static expansion agent 26 does not ignite, vibrate, make noise, or have harmful gases during use. The material itself is an inorganic material, which is inherently safe, and can be stored, transported, and managed as cement products, and is easy to use. Moreover, the expansion performance of the static expansion agent has the characteristics of long duration and large expansion force. For example, the expansion stress of a static expansion agent reaches 33MPa at 12h, and the expansion stress exceeds 50Mpa after 24h, which is greater than the tensile strength of coal, and it is easier to achieve the purpose of static cracking of coal and rock.

[0049] Among them, the drilling equipment used for drilling is installed on the scraper conveyor 30 in the fully-mechanized caving working face, and the installation position on the scraper conveyor 30 is adjustable. The drill bit 1 in the drilling equipment is driven by a hydraulic motor 2, and the power source of the hydraulic motor 2 is the emulsion pump station in the fully-mechanized caving working face. In this embodiment, the drilling equipment used is installed on the scraper conveyor 30 in the fully-mechanized caving working face, and the installation position of the drilling equipment is adjustable, so that no power source is required, and the power source of the scraper conveyor is directly used, which has a large driving force and can improve work efficiency. Moreover, compared with independent drilling equipment, the drilling equipment used in this embodiment is small in size and highly flexible, and can be applied to a variety of scenarios.

[0050] like Figures 10 to 13 As shown, the embodiment of the present invention also includes a drilling and pouring device, the drilling and pouring device includes:

[0051] Drilling equipment, the position of the drilling equipment is adjustably installed on the scraper conveyor 30 in the fully mechanized caving working face, the drilling equipment includes a drill bit 1 and a hydraulic motor 2, the hydraulic motor 2 drives the drill bit 1 to rotate, and the power source of the hydraulic motor 2 is the emulsion pump station in the fully mechanized caving working face;

[0052] The hole sealer includes an elastic tube 19 and a hole plug 16 disposed at one end of the elastic tube 19, the elastic tube 19 is used to penetrate into the borehole of the top coal 28 and contain the injected static expansion agent 26, and the hole plug 16 is used to seal the hole of the borehole;

[0053] The grouting and stirring integrated machine is used to stir the static expansion agent 26 added with water, and input the stirred static expansion agent 26 into the elastic cylinder 19.

[0054] In this embodiment, the drilling equipment is positionally adjustable and installed on the scraper conveyor 30 in the fully mechanized caving working face. It is connected to the hydraulic motor 2 through the water inlet 10 through the emulsion pump station in the fully mechanized caving working face, providing a power source for the hydraulic motor 2. The hydraulic motor 2 drives the drill bit 1 to rotate and perform drilling. The driving force is large and the working efficiency is high. Moreover, the elastic cylinder 19 is made of rubber material and can expand, which is convenient for subsequent expansion with the static expansion agent 26 in the borehole. The grouting and mixing integrated machine stirs the static expansion agent 26 added with water so that the water and the static expansion agent 26 are evenly mixed according to the proportion. After reaching a state that can expand, the stirred static expansion agent 26 is input into the elastic cylinder 19, and then the elastic cylinder 19 is inserted into the borehole of the top coal 28, waiting for the expansion to cause the top coal 28 to crack. The operation is simple and convenient.

[0055] like Fig.10As shown, the drilling equipment also includes a base 5, a support column 7, a drilling rig support 4, a propulsion hydraulic cylinder 3 and a sliding seat 27. The base 5 is installed on the groove 13 of the scraper conveyor 30, the support column 7 can be lifted and lowered on the base 5, the drilling rig support 4 is installed on the support column 7, the propulsion hydraulic cylinder 3 is fixedly installed on the drilling rig support 4, the sliding seat 27 can be slidably installed on the drilling rig support 4, the hydraulic motor 2 is installed on the sliding seat 27, and the propulsion hydraulic cylinder 3 is used to push the sliding seat 27 to move in the drilling direction. In this embodiment, the base 5 is installed on the groove 13 of the scraper conveyor, providing a stable working platform for the drilling equipment, ensuring the stability of the equipment during operation and the safety of personnel working on the coal mining face 35. The support column 7 can be lifted and lowered and installed on the base 5 by fastening screws 15, so that the drilling equipment can adapt to the drilling requirements of different heights, increasing the flexibility and applicability of the equipment. The propulsion hydraulic cylinder 3 is used to push the sliding seat 27 to move in the drilling direction. Accurate drilling depth and speed control can be achieved through hydraulic control, thereby improving drilling accuracy. The hydraulic motor 2 is mounted on the sliding seat 27, and can quickly push and withdraw the drill bit, thereby improving the drilling efficiency. The device is small in size and compact in space, and can perform drilling operations under different geological conditions, with good adaptability.

[0056] like Fig.10 As shown, the drilling equipment further includes a rotating disk 6, a rotating seat 8 and an auxiliary column 9. The rotating disk 6 is arranged between the base 5 and the lower end of the supporting column 7. The rotating disk 6 is used to drive the supporting column 7 to rotate along its own axis. The rotating seat 8 is arranged between the upper end of the supporting column 7 and the drilling rig support 4. The rotating seat 8 is used to drive the drilling rig support 4 to swing along the horizontal axis. The auxiliary column 9 is positionally adjustable and installed on the cable trough 14 of the scraper conveyor 30. The auxiliary column 9 can be raised and lowered. The upper end of the auxiliary column 9 can be detachably contacted with the drilling rig support 4 to support the drilling rig support 4. In this embodiment, the rotating disk 6 and the rotating seat 8 allow the supporting column 7 and the drilling rig support 4 to rotate and swing along different axes, thereby increasing the positioning flexibility of the drilling equipment in space. Through the rotation and swinging functions, the operator can easily adjust the drilling direction according to the actual drilling position, thereby improving the convenience of operation. The auxiliary column 9 provides an additional support point, which enhances the stability of the entire drilling equipment, especially when working on an inclined or uneven surface. The base 5 is installed on the trough side 13 of the scraper conveyor, and the auxiliary column 9 is installed on the cable trough 14. Such a layout can reduce the interference with the normal operation of the scraper conveyor.

[0057] like Fig.11 and 13As shown, the hole sealer also includes an exhaust pipe 17 and a grouting pipe 18. Both the exhaust pipe 17 and the grouting pipe 18 penetrate into the elastic tube 19 from the orifice plug 16. The length of the exhaust pipe 17 penetrating into the elastic tube 19 is greater than the length of the grouting pipe 18 penetrating into the elastic tube 19. The grouting pipe 18 is connected to the grouting and mixing machine through a detachable pipeline. In this embodiment, the grouting pipe 18 is connected to the grouting and mixing machine, and the mixed water and static expansion agent 26 are injected into the elastic tube 19. The orifice plug 16 seals the entire sealer. When the static expansion agent 26 flows out of the exhaust pipe 17, it means that the elastic tube 19 is already filled with the static expansion agent 26. The injection is stopped, and the cracks in the top coal 28 expand as shown in FIG. Fig.14 Moreover, by adjusting the lengths of the exhaust pipe 17 and the grouting pipe 18, it is possible to adapt to boreholes of different depths and diameters, thereby improving the applicability of the hole sealer.

[0058] like Fig.12 As shown, the grouting and mixing machine includes a mixing tank, a rotary motor 20, a stirring blade 23 and a grouting pump 24. The mixing tank is used to contain a static expansion agent 26 and water. The rotary motor 20 is installed on the top of the mixing tank. The rotary motor 20 drives the stirring blade 23 to rotate for stirring. The grouting pump 24 is used to deliver the stirred static expansion agent 26 to the elastic cylinder 19. In this embodiment, the downhole working surface emulsion pump interface is connected to the mixing barrel emulsion pressurization port 21, and the downhole working surface emulsion pressure drives the rotary motor 20 to work through the emulsion pressurization port 21. The rotary motor 20 drives the stirring blade 23 to rotate to ensure that the static expansion agent 26 is fully mixed with water and improve the effect of the expansion agent. After stirring evenly, the grouting pump 24 is turned on to deliver the static expansion agent 26 to the elastic cylinder 19 through the grouting pipe 18 connected to the grouting port 25. Moreover, the grouting pump 24 can work continuously, and the stirred static expansion agent 26 is delivered to the elastic cylinder 19 in time to maintain the continuity of the operation. In this embodiment, the mixing tank is provided with a discharge port 22, which is used to discharge the residual materials in the mixing tank when the grouting and mixing machine stops working or needs to be cleaned, so as to ensure the cleanliness of the mixing tank.

[0059] The present invention provides a method for fracturing top coal with a static expansion agent and a drilling and grouting device. By using a static expansion agent 26 in the top coal 28 for fracturing, the strength of the top coal 28 can be effectively reduced, the natural fall of the top coal 28 can be promoted, and the recovery rate of the top coal 28 in the fully mechanized caving working face can be improved. At the same time, the drilling equipment is installed on the scraper conveyor 30, and the drilling operation can be performed without affecting the normal coal mining operation, thereby improving the work efficiency. The use of the static expansion agent 26 avoids the safety hazards brought by the traditional blasting method, making the mining process safer. In addition, the present invention also has the following technical advantages:

[0060] (1) Flexible use and strong adaptability. Convenient for construction at any location within the coal mine working surface;

[0061] (2) Low cost. Static expansion agent 26 and sealer are cheap;

[0062] (3) The equipment is easy to transport and use. The mixing tank, static expansion agent 26 and hole sealer can be carried by a single coal miner; the drilling equipment is small in size, has its own power source mechanism, and can slide at the groove side 13, which is easy to carry;

[0063] (4) High safety. The static expansion agent 26 can achieve safe crushing of the top coal 28 without vibration, noise, flying stones, harmful gases, pollution or environmental hazards.

[0064] (5) Easy to operate. Static expansion agent 26 has the characteristics of low detonation velocity, slow loading and simple operation, which is convenient for coal miners to operate and learn.

[0065] (6) Good crushing effect. The expansion pressure generated by the static expansion agent 26 can reach 50-70 MPa, which is much greater than the tensile strength of coal and can easily crack the top coal 28.

[0066] (7) Flexible construction plan. The amount of static expansion agent 26 can be dynamically changed according to the strength of the top coal 28, on-site construction and production progress, and factors such as the drilling spacing, length and angle can also be dynamically changed.

[0067] (8) The drilling equipment is flexible to operate. The existence of the supporting column 7, the auxiliary column 9, the rotating disk 6 and the rotating seat 8 enables the drilling equipment to flexibly adjust the lifting height up and down, and adjust the offset rotation angle left and right, so as to realize multi-angle drilling.

[0068] (9) Convenient driving. Since there is a high-pressure emulsion interface in the coal mining working face, the emulsion drilling rig is used to easily connect the high-pressure emulsion pump station on the working face to drive the hydraulic motor 2 to drive the drill bit 1 to drill holes.

[0069] The above is only an optional embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0070] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0071] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of this solution. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being only exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0072] In the description of this scheme, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing this scheme and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the scope of protection of this scheme; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0073] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0074] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only to facilitate the distinction between corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this scheme.

Claims

1. A method for cracking top coal (28) using a static expansion agent (26), characterized in that: The method for using the static expansion agent (26) to crack top coal (28) comprises: The daily mining length of the fully-mechanized caving working face along its own extension direction is set as L / N, a hole is drilled on the top coal (28) of the fully-mechanized caving working face, the length of the hole along the extension direction of the fully-mechanized caving working face is L, a static expansion agent (26) is poured into the hole and the hole mouth of the hole is blocked, and the top coal (28) generates cracks that gradually increase during the expansion process of the static expansion agent (26); wherein, The plurality of boreholes are divided into a first group of boreholes (31) to an Nth group of boreholes, the distance between two adjacent boreholes in each group of boreholes is ND, the plurality of groups of boreholes are constructed in sequence on different production days, the plurality of groups of boreholes are staggered in the width direction and extension direction of the top coal (28), and each group of boreholes is constructed in the upper front of the currently advanced mining area; wherein, on the first day, the first group of boreholes is constructed, static expansion agent (26) is poured, and the boreholes are blocked, until on the Nth day, the Nth group of boreholes is constructed, static expansion agent (26) is poured, and the boreholes are blocked, and after the construction of the Nth group of boreholes is completed, the distance between any two adjacent boreholes in the width direction of the top coal (28) is D; As coal mining progresses, drilling, injection of static expansion agent (26) and sealing operations from the first group of holes to the Nth group of holes are cyclically performed in the advancing direction; wherein, after the coal mining machine and hydraulic support (29) in the fully mechanized caving working face are advanced forward, a free surface is left for the top coal (28) originally located above the hydraulic support (29), and the top coal (28) here is broken and falls due to the generated cracks.

2. The method for fracturing top coal (28) using a static swelling agent (26) according to claim 1, characterized in that: The drilling, injection of static expansion agent (26) and plugging operations are performed during the maintenance time of the production day.

3. The method for fracturing top coal (28) using a static swelling agent (26) according to claim 2, characterized in that: The daily mining length of the fully mechanized caving working face along its own extension direction is L / 3, and the multiple boreholes are divided into a first group of boreholes, a second group of boreholes and a third group of boreholes, and the distance between two adjacent boreholes in each group of boreholes is 3D.

4. The method for fracturing top coal (28) using a static swelling agent (26) according to claim 1, characterized in that: The static expansion agent (26) is a powdered inorganic material that expands after mixing with water. After the static expansion agent (26) is mixed with water, it starts to generate expansion force in 1 to 2 hours and reaches the maximum expansion force in 11 to 13 hours.

5. The method for fracturing top coal (28) using a static swelling agent (26) according to claim 1, characterized in that: The drilling equipment used for drilling holes is installed on a scraper conveyor (30) in a fully mechanized caving working face, and the installation position on the scraper conveyor (30) is adjustable. The drill bit (1) in the drilling equipment is driven by a hydraulic motor (2), and the power source of the hydraulic motor (2) is an emulsion pump station in the fully mechanized caving working face.

6. A drilling and grouting device, characterized in that: The drilling and grouting equipment adopts the method of fracturing top coal (28) by using a static expansion agent (26) as described in any one of claims 1 to 5, and the drilling and grouting equipment comprises: A drilling device, the position of which can be adjusted and installed on a scraper conveyor (30) in a fully mechanized caving working face, the drilling device comprising a drill bit (1) and a hydraulic motor (2), the hydraulic motor (2) driving the drill bit (1) to rotate, the power source of the hydraulic motor (2) being an emulsion pump station in the fully mechanized caving working face; A hole sealer, the hole sealer comprising an elastic tube (19) and a hole plug (16) arranged at one end of the elastic tube (19), the elastic tube (19) being used to penetrate into a borehole of top coal (28) and contain an injected static expansion agent (26), and the hole plug (16) being used to seal the hole of the borehole; The grouting and stirring machine is used to stir the static swelling agent (26) added with water, and input the stirred static swelling agent (26) into the elastic cylinder (19).

7. The drilling and injection equipment according to claim 6, characterized in that: The drilling equipment also includes a base (5), a support column (7), a drilling rig support (4), a propulsion hydraulic cylinder (3) and a sliding seat (27); the base (5) is installed on the groove side (13) of the scraper conveyor (30); the support column (7) is movably arranged on the base (5); the drilling rig support (4) is installed on the support column (7); the propulsion hydraulic cylinder (3) is fixedly installed on the drilling rig support (4); the sliding seat (27) is slidably installed on the drilling rig support (4); the hydraulic motor (2) is installed on the sliding seat (27); and the propulsion hydraulic cylinder (3) is used to push the sliding seat (27) to move in the drilling direction.

8. The drilling and injection equipment according to claim 7, characterized in that: The drilling equipment further comprises a rotating disk (6), a rotating seat (8) and an auxiliary column (9), wherein the rotating disk (6) is arranged between the base (5) and the lower end of the supporting column (7), and the rotating disk (6) is used to drive the supporting column (7) to rotate along its own axis, the rotating seat (8) is arranged between the upper end of the supporting column (7) and the drilling rig support (4), and the rotating seat (8) is used to drive the drilling rig support (4) to swing along a horizontal axis, and the auxiliary column (9) is positionally adjustable and mounted on the cable trough (14) of the scraper conveyor (30), and the auxiliary column (9) can be raised and lowered, and the upper end of the auxiliary column (9) can be detachably contacted with the drilling rig support (4) to support the drilling rig support (4).

9. The drilling and injection equipment according to claim 6, characterized in that: The hole sealer further comprises an exhaust pipe (17) and a grouting pipe (18), wherein both the exhaust pipe (17) and the grouting pipe (18) penetrate into the elastic tube (19) from the hole plug (16), the length of the exhaust pipe (17) penetrating into the elastic tube (19) being greater than the length of the grouting pipe (18) penetrating into the elastic tube (19), and the grouting pipe (18) is connected to the grouting and mixing integrated machine via a detachable pipeline.

10. The drilling and injection equipment according to claim 6, characterized in that: The grouting and stirring machine comprises a stirring tank, a rotary motor (20), a stirring blade (23) and a grouting pump (24); the stirring tank is used to contain the static expansion agent (26) and water; the rotary motor (20) is installed on the top of the stirring tank; the rotary motor (20) drives the stirring blade (23) to rotate for stirring; and the grouting pump (24) is used to transport the stirred static expansion agent (26) into the elastic cylinder (19).

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