Method for detecting bidirectional shaped charge tension blasting directional presplitting effect of coal-pillar-free self-forming roadway roof

Abstract

The invention relates to the technical field of coal mine non-pillar mining, and discloses a non-pillar self-forming roadway roof bidirectional shaped charge tension blasting directional presplitting effect detection method which comprises the following steps: S1, drilling a directional presplitting drill hole for bidirectional shaped charge tension blasting in a roof at a mining roadway position of a coal face; s2, directional pre-splitting drill holes for detection are selected and numbered; s3, assembly of the detection system for fracture seepage flow measurement is completed; and S4, a detection system is adopted for conducting native fracture seepage flow measurement on the hole wall of the directional pre-splitting drill hole, and seepage flow data of a native fracture are recorded. According to the method, the bidirectional shaped charge tension blasting directional presplitting effect of the coal-pillar-free self-forming roadway roof can be more accurately detected, so that a basis is provided for further optimizing parameters of bidirectional shaped charge tension blasting presplitting of the coal-pillar-free self-forming roadway roof, the success rate of presplitting of the coal-pillar-free self-forming roadway roof is increased, and the safety risk caused by the poor roof cutting effect is avoided.

Description

Technical Field

[0001] This invention relates to the field of coal pillarless mining technology, and in particular to a method for detecting the directional pre-splitting effect of bidirectional energy-concentrating tension blasting on the roof of a self-forming roadway without coal pillars. Background Technology

[0002] Coal is my country's primary energy source, accounting for approximately 57% of the country's primary energy consumption. Safe coal production is crucial to the stability of energy supply and the implementation of energy strategies, serving as a reliable guarantee for national economic development and a "ballast stone" for energy security.

[0003] Traditional pillar mining techniques not only result in a serious waste of coal resources but also trigger a series of mine stress problems and adversely affect the ecological environment. In contrast, the pillarless self-forming roadway mining technology, based on the "short-arm beam" theory proposed by Academician He Manchao's team, utilizes directional pre-splitting of the roof to actively cut and relieve pressure. It uses part of the roof rock to form roadway sides, eliminating the need for coal pillars and roadway backfilling, thus achieving automatic roadway formation along the goaf. Combined with its independently developed high-prestressed NPR excavation compensation support technology to suppress surrounding rock deformation, and anti-scour and pressure-reducing rock-blocking support technology that can buffer and resist loads, this core technical system achieves the technological goals of "being able to hold, cut, descend, and protect effectively." This method differs from the traditional longarm mining layout of "one face, two roadways". When mining one working face, only one roadway needs to be excavated, and the other roadway is automatically formed by cutting the roof to relieve pressure. Furthermore, there is no need to leave protective coal pillars. The working face changes from "skipping mining" to continuous mining, which effectively reduces the periodic pressure on the roadway and has outstanding safety and economic benefits.

[0004] During the process of roof cutting and pressure relief in pillarless mining, the effect of bidirectional energy-concentrating tension blasting and directional pre-splitting of the roof will produce significant differences in the stress condition of the roof, the manifestation law of mine pressure, and the collapse of the roof in the goaf, thus affecting the stability of the roadway and the roadway formation effect.

[0005] Currently, the common method for detecting the directional pre-splitting effect of bidirectional shaped charge blasting in coal mines is through borehole inspection. This involves inserting a probe deep into the borehole to collect images or videos of the borehole wall and transmitting the data to ground or terminal equipment to help understand the fracture conditions within the borehole. However, borehole inspection can only observe cracks on the surface of the borehole wall and cannot probe the internal fracture conditions, thus failing to accurately determine the internal blasting effect.

[0006] To more accurately evaluate the effectiveness of directional blasting pre-splitting of the roof, a method for detecting the effect of bidirectional shaped charge tensioning directional pre-splitting of the roof in self-forming roadways without coal pillars is proposed. This method detects and compares the changes in borehole permeability before and after bidirectional tensioning pre-splitting to understand the development of fractures inside the borehole after directional blasting, thereby determining the effectiveness of the directional pre-splitting of the roof. Summary of the Invention

[0007] To address the technical problems existing in the prior art, this invention provides a method for detecting the directional pre-splitting effect of bidirectional shaped energy tension blasting on the roof of a self-forming roadway without coal pillars.

[0008] This invention employs the following technical solution: a method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars, comprising the following steps:

[0009] S1. Drill directional pre-splitting boreholes for bidirectional shaped charge tensioning blasting on the roof of the coal mining face at the location of the coal mining roadway.

[0010] S2. Select and number the directional pre-splitting boreholes for testing;

[0011] S3. Assemble the detection system for measuring fracture seepage flow.

[0012] S4. Use a detection system to measure the seepage flow of the original fractures in the borehole wall of the directional pre-splitting borehole, and record the seepage flow data of the original fractures.

[0013] S5. Perform bidirectional shaped tensioning directional pre-splitting blasting on the top plate of the directional pre-splitting borehole;

[0014] S6. The seepage flow rate of the directional pre-splitting borehole after blasting is measured using the method in step S4, and the seepage flow rate data of the fracture after blasting is recorded.

[0015] S7. Determine the effect of bidirectional shaped charge tensioning blasting based on the seepage flow data before and after the blast.

[0016] As a further improvement to the above scheme, the detection system in step S3 includes a plugging component that extends into the directional pre-splitting borehole, as well as a seepage power mechanism and a plugging power mechanism for performing seepage measurement.

[0017] The plugging assembly includes a top plugging mechanism, a penetration injection mechanism, and a bottom plugging mechanism arranged in sequence.

[0018] As a further improvement to the above scheme, the permeation power mechanism includes a test bench and a booster pump installed on top of the test bench. The input end of the booster pump is connected to a feed pipe, and the output end of the booster pump is connected to a discharge pipe. A pressure gauge, a pressure control valve, a valve, an exhaust valve, and a flow meter are installed on the discharge pipe in sequence. The discharge pipe is used to provide the detection system with a stable pressure permeation medium for permeation detection. The discharge pipe is fixedly connected to a bracket connected to the test bench. A valve is installed on the feed pipe.

[0019] As a further improvement to the above solution, the sealing power mechanism includes a test bench 2, and a delivery pipe is provided on the top of the test bench 2. The delivery pipe is used to provide the power medium for sealing to the detection system. The delivery pipe is sequentially equipped with a valve 4, a pressure gauge 2, a valve 2, and an exhaust valve 2. The delivery pipe is fixedly connected to a bracket 2 that is connected to the test bench 2.

[0020] As a further improvement to the above solution, the top sealing mechanism includes a support tube, a sealing airbag extending downwards is fixedly sleeved on the outer ring of the support tube, a connecting lug is fixedly connected to the bottom inner ring of the sealing airbag along its axial direction, a connecting air pipe communicating with the sealing airbag is fixedly connected to the inner ring of the support tube, and a connecting pipe that docks with the permeation injection mechanism is slidably sleeved at the bottom of the connecting air pipe.

[0021] As a further improvement to the above solution, the permeation injection mechanism includes a second support tube that is connected to the top sealing mechanism. A baffle is fixedly connected to the inner ring of the top of the second support tube. A second connecting air tube is fixedly sleeved on the baffle. A diversion hood is provided at the bottom of the baffle and is fixedly sleeved on the inner ring of the second support tube. A spray hole penetrating the second support tube is opened on the outer side of the diversion hood. A feed pipe is provided on the inner side of the diversion hood.

[0022] As a further improvement to the above solution, the bottom sealing mechanism includes a support tube three that docks with the permeation injection mechanism. A sealing airbag two with an annular structure is fixedly sleeved on the top outer ring of the support tube three. A connecting ear two distributed along its array is fixedly connected to the top inner ring of the sealing airbag two. A connecting air pipe three is provided on the inner ring of the support tube three. A connecting pipe two that docks with the permeation injection mechanism is slidably sleeved on the top of the connecting air pipe three. A branch pipe communicating with the sealing airbag two is provided on one side of the connecting air pipe three.

[0023] As a further improvement to the above scheme, in step S5, explosive charge for pre-splitting blasting is buried at the designated position of the directional pre-splitting borehole, the directional pre-splitting borehole is sealed with sealing mud at the opening of the directional pre-splitting borehole, and then the directional pre-splitting borehole is subjected to bidirectional shaped charge tensioning directional pre-splitting blasting of the top plate using explosive charge.

[0024] As a further improvement to the above scheme, in step S7, the seepage flow rate of the borehole after blasting is compared with the seepage flow rate before blasting. If the seepage flow rate of the borehole after blasting is much greater than that before blasting, then the bidirectional shaped charge tensioning blasting effect is better and the top cutting effect is ideal. In addition, when a large amount of water is detected flowing out of the adjacent borehole, it can also be said that the bidirectional shaped charge tensioning blasting effect is better.

[0025] As a further improvement to the above solution, the detection system also includes a control box, which contains a controller, and a display screen is installed on one side of the control box to display the pressure and flow rate during the detection process.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. This invention can more accurately detect the directional pre-splitting effect of bidirectional shaped energy tension blasting on the roof of a self-forming roadway without coal pillars, thereby providing a basis for further optimizing the parameters of bidirectional shaped energy tension blasting pre-splitting on the roof of a self-forming roadway without coal pillars, improving the success rate of pre-splitting on the roof of a self-forming roadway without coal pillars, and avoiding the safety risks caused by poor roof cutting effect.

[0028] 2. This invention adopts a modular design, which allows inspectors to assemble the components according to their testing needs during the testing process. This improves the convenience and adaptability of the testing process. It allows for the selection of components of appropriate length and specifications for assembly based on actual needs, making it suitable for different types of testing requirements. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure provided by the present invention;

[0030] Figure 2 This is a structural schematic diagram of the cross-sectional view of the mining roadway provided by the present invention;

[0031] Figure 3 A schematic diagram of the structure selected for directional pre-fracture borehole detection in a mining roadway provided by the present invention;

[0032] Figure 4 This is a schematic diagram of the detection system provided by the present invention;

[0033] Figure 5 A schematic diagram of the permeation power mechanism provided by the present invention;

[0034] Figure 6 A schematic diagram of the sealing power mechanism provided by the present invention;

[0035] Figure 7 This is a schematic diagram of the structure of the sealing assembly provided by the present invention;

[0036] Figure 8 A cross-sectional view of the sealing assembly provided by the present invention;

[0037] Figure 9 A schematic diagram of the top sealing mechanism provided by the present invention;

[0038] Figure 10 A schematic diagram of the permeation injection mechanism provided by the present invention;

[0039] Figure 11 A schematic diagram of the bottom sealing mechanism provided by the present invention.

[0040] Explanation of key symbols:

[0041] 1. Mining roadway; 2. Anchor bolt structure; 5. Directional pre-splitting borehole; 6. Coal face; 7. Detection system; 8. Permeation power mechanism; 9. Sealing power mechanism; 11. Top sealing mechanism; 12. Permeation injection mechanism; 13. Bottom sealing mechanism; 21. Support pipe one; 22. Sealing airbag one; 23. Connecting lug one; 24. Connecting air pipe one; 25. Butt pipe one; 31. Support pipe two; 32. Baffle; 33. Connecting air pipe two; 34. Diversion hood; 35. Nozzle; 36. Feed pipe; 41. Support pipe 3; 42. Sealing airbag 2; 43. Connecting ear 2; 44. Branch pipe; 45. Connecting air pipe 3; 46. Connecting pipe 2; 81. Test bench 1; 82. Booster pump; 83. Feed pipe; 84. Discharge pipe; 85. Pressure gauge 1; 86. Pressure control valve; 87. Valve 1; 88. Exhaust valve 1; 89. Flow meter; 810. Support 1; 811. Valve 3; 91. Test bench 2; 92. Delivery pipe; 93. Pressure gauge 2; 94. Valve 2; 95. Exhaust valve 2; 96. Support 2; 97. Valve 4. Detailed Implementation

[0042] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0043] Example 1:

[0044] Please combine Figures 1-4 This embodiment of a method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars includes the following steps:

[0045] S1. Drill directional pre-splitting borehole 5 on the roof of the coal mining face 6 at the location of the mining roadway 1 for bidirectional shaped charge tensioning blasting.

[0046] Among them, the mining roadway 1 is equipped with an anchor bolt structure 2 for anchoring. The anchor bolt structure 2 adopts any one of the following: anchor bolt, ordinary anchor cable, and constant resistance anchor cable.

[0047] S2. Select 5 directional pre-splitting boreholes for testing and number them;

[0048] S3. Complete the assembly of the detection system 7 for measuring fracture seepage flow;

[0049] S4. The seepage flow rate of the original fractures in the borehole wall of the directional pre-splitting borehole 5 is measured using the detection system 7, and the seepage flow rate data of the original fractures is recorded.

[0050] S5. Perform bidirectional shaped tensioning directional pre-splitting blasting on the top plate of directional pre-splitting borehole 5.

[0051] In this process, explosive charge for pre-splitting blasting is buried at the designated position of the directional pre-splitting borehole 5. The directional pre-splitting borehole 5 is sealed with sealing mud at the opening. Then, the directional pre-splitting borehole 5 is subjected to bidirectional shaped energy tensioning directional pre-splitting blasting of the top plate using explosive charge.

[0052] S6. The seepage flow rate of the directional pre-splitting borehole 5 after blasting is measured using the method in step S4, and the seepage flow rate data of the fracture after blasting is recorded.

[0053] S7. Use the seepage flow data before and after the blast to determine the effect of bidirectional shaped charge tensioning blasting.

[0054] Example 2:

[0055] Combination Figures 5-11 The further improvement of this embodiment based on embodiment 1 is that the detection system 7 includes a plugging component 7 that extends into the directional pre-splitting borehole 5, as well as a seepage power mechanism 8 and a plugging power mechanism 9 for performing seepage measurement.

[0056] The sealing assembly 7 includes a top sealing mechanism 11, a permeation injection mechanism 12, and a bottom sealing mechanism 13 arranged sequentially.

[0057] The permeation power mechanism 8 includes a test bench 81 and a booster pump 82 installed on the top of the test bench 81. The input end of the booster pump 82 is connected to a feed pipe 83, and the output end of the booster pump 82 is connected to a discharge pipe 84. The discharge pipe 84 is equipped with a pressure gauge 85, a pressure control valve 86, a valve 87, an exhaust valve 89, and a flow meter 89 arranged in sequence. The discharge pipe 84 is used to provide the detection system 7 with a pressure-stable permeation medium for permeation detection. The discharge pipe 84 is fixedly connected to a bracket 810 connected to the test bench 81. The feed pipe 83 is equipped with a valve 811.

[0058] The sealing power mechanism 9 includes a test bench 2 91. A delivery pipe 92 is provided on the top of the test bench 2 91. The delivery pipe 92 is used to provide the power medium for sealing to the detection system 7. A valve 4 97, a pressure gauge 2 93, a valve 2 94 and an exhaust valve 2 95 are installed in sequence on the delivery pipe 92. A bracket 2 96 connected to the test bench 2 91 is fixed to the delivery pipe 92.

[0059] The top sealing mechanism 11 includes a support tube 21, a sealing airbag 22 extending downward is fixedly sleeved on the outer ring of the support tube 21, a connecting lug 23 arranged sequentially along its axis is fixedly sleeved on the bottom inner ring of the sealing airbag 22, a connecting air pipe 24 communicating with the sealing airbag 22 is fixedly sleeved on the inner ring of the support tube 21, and a connecting pipe 25 that is connected to the permeation injection mechanism 12 is slidably sleeved on the bottom of the connecting air pipe 24.

[0060] The permeation injection mechanism 12 includes a second support tube 31 that is connected to the top sealing mechanism 11. A baffle 32 is fixedly connected to the inner ring of the top of the second support tube 31. A second connecting air pipe 33 is fixedly sleeved on the baffle 32. A diversion hood 34 is provided at the bottom of the baffle 32 and is fixedly sleeved on the inner ring of the second support tube 31. A spray hole 35 penetrating the second support tube 31 is opened on the outer side of the diversion hood 34. A feed pipe 36 is provided on the inner side of the diversion hood 34.

[0061] The bottom sealing mechanism 13 includes a support tube 3 41 that docks with the permeation injection mechanism 12. The outer ring of the top of the support tube 3 41 is fixedly sleeved with a ring-shaped sealing airbag 2 42. The inner ring of the top of the sealing airbag 2 42 is fixedly connected with connecting ears 2 43 distributed along its array. The inner ring of the support tube 3 41 is provided with a connecting air pipe 3 45. The top of the connecting air pipe 3 45 is slidably sleeved with a connecting pipe 2 46 that docks with the permeation injection mechanism 12. A branch pipe 44 communicating with the sealing airbag 2 42 is provided on one side of the connecting air pipe 3 45.

[0062] When installing the sealing assembly 7, the top sealing mechanism 11, the permeation injection mechanism 12, and the bottom sealing mechanism 13 are connected in sequence. The connecting pipe 1 25 is connected to the connecting air pipe 2 33, and the connecting pipe 1 25 and the connecting air pipe 2 33 are sealed. Then, the support pipe 1 21 is sleeved with the support pipe 2 31, and the support pipe 1 21 and the support pipe 2 31 are fixed with bolts. The sealing airbag 1 22 is pulled down to cover the outside of the support pipe 2 31, and the connecting ear 1 23 is fixed to the outer wall of the support pipe 2 31 with bolts. After that, the connection of the permeation injection mechanism 12 and the bottom sealing mechanism 13 is completed by the above method. The feed pipe 36 is connected to the output end of the discharge pipe 84 of the permeation power mechanism 8 through a pipe. The connecting air pipe 3 45 is connected to the output end of the delivery pipe 92 of the sealing power mechanism 9 through a pipe.

[0063] When measuring the seepage flow of a directional pre-splitting borehole, the assembled detection system 7 is transported to the vicinity of the directional pre-splitting borehole 5 to be tested in the coal mining face 6. The external seepage medium is connected to the seepage power mechanism 8 through a pipeline, and the external air source is connected to the sealing power mechanism 9. At the same time, the seepage power mechanism 8 and the sealing power mechanism 9 are connected through a pipeline. Then, the sealing component is put into the directional pre-splitting borehole 5 to be tested. The sealing power mechanism 9 is used to transport the sealing air source to the top sealing mechanism 11 and the bottom sealing mechanism 13 to seal the directional pre-splitting borehole 5 from both ends. Then, the seepage power mechanism 8 is used to transport the seepage medium to the seepage injection mechanism 12 to perform seepage detection on the directional pre-splitting borehole 5.

[0064] During airbag sealing, an external air source is connected to the delivery pipe 92. The pressure of the delivered air source is controlled by pressure gauge 93 and valve 94. The gas delivered by the delivery pipe 92 is transported along the pipeline to the connecting air pipe 45 of the bottom sealing mechanism 13. Then, the gas enters the interior of the sealing airbag 42 along the branch pipe 44. The sealing airbag 42 inflates, and the outer ring of the sealing airbag 42 abuts against the inner wall of the directional pre-splitting borehole 5 to seal the directional pre-splitting borehole 5. The inner side of the sealing airbag 42 is connected to the support pipe 31 and the support... Pipe 3 41 contacts and blocks support pipe 2 31 and support pipe 3 41, achieving a sealing operation at the connection between support pipe 2 31 and support pipe 3 41. The same sealing airbag 1 22 is installed to seal the inner wall of the directional pre-splitting borehole 5 and the connection between support pipe 1 21 and support pipe 2 31, thereby completing the sealing operation of the directional pre-splitting borehole 5. The permeating medium enters the diversion hood 34 along the feed pipe 36 and then sprays out from the nozzle 35 into the sealing airbag 1 22 and sealing airbag 2 42 to form the detection sealing hole section.

[0065] During the penetration testing process, the testing system 7 is checked for leaks beforehand to ensure that the pipeline is well sealed and to avoid inaccurate data acquisition due to media leakage.

[0066] To perform an airbag sealing test, close the exhaust valve 2 95 and open valve 4 97 and valve 2 94, allowing the air pressure on the pressure gauge 2 93 on the delivery pipe 92 to slowly rise to 0.3 MPa to achieve the sealing state; then close valve 4 97 and observe whether there is a significant drop in inflation pressure to determine if there is a serious leak in the inflation line. If there is a serious leak, the location should be identified and eliminated until it passes the test.

[0067] During the penetration test, open valve 3 (811) and valve 1 (87), and use booster pump 82 to maintain the output medium pressure at 0.1 MPa. At the same time, ensure that the pressure of pressure gauge 2 (93) in the sealing power mechanism 9 is stable at 0.3 MPa. Maintain a water injection pressure of 0.1 MPa and inject water into the sealing section at a constant pressure. When the water injection flow rate reaches equilibrium with the leakage flow rate from the cracks in the borehole wall, the water injection pressure and flow rate will stabilize. After the flow rate stabilizes, observe and record the water injection flow rate per minute. After the water injection flow rate observation is completed, close valve 3 (811) and valve 1 (87) to stop water injection, open vent valve 2 (95) to release air, causing the sealing airbag to contract and the water stored in the borehole section to drain out.

[0068] After completing the measurement of the seepage flow rate of the original fractures in the directional pre-splitting borehole 5, the sealing assembly is extracted from the directional pre-splitting borehole 5. Explosive charge for pre-splitting blasting is buried at the designated position in the directional pre-splitting borehole 5. The opening of the directional pre-splitting borehole 5 is sealed with sealing mud. Then, the directional pre-splitting borehole 5 is subjected to bidirectional shaped charge tensioning directional pre-splitting blasting of the roof using explosive charge. An electronic detonator for initiation is pre-embedded in the explosive charge and connected to an external power source for initiation using a wire. After completing the directional pre-splitting blasting of the directional pre-splitting borehole 5, the directional pre-splitting borehole 5 is cleaned to remove the explosive mud and other debris, reducing the blockage of the fractures by the stemming mud and reducing detection errors. Afterward, the sealing assembly is reinserted into the directional pre-splitting borehole 5, and the fracture seepage flow rate of the directional pre-splitting borehole 5 after blasting is measured in the same manner as described above.

[0069] Comparing the seepage flow rate before blasting with the seepage flow rate after blasting, if the seepage flow rate of the borehole after blasting is much greater than that before blasting, then the bidirectional shaped charge tensioning blasting effect is better and the top cutting effect is ideal. In addition, when a large amount of water flows out of the adjacent boreholes, it can also be said that the bidirectional shaped charge tensioning blasting effect is better.

[0070] For clay mineral-based roofs that soften when exposed to water, the high-pressure water source at the water inlet of the water injection platform can be replaced with a high-pressure air source; for clay rock-based roofs that soften when exposed to water, a large amount of air gushing out from adjacent boreholes indicates a good effect.

[0071] Example 3:

[0072] Based on Embodiment 1, this embodiment is further improved in that: the bottom outer ring of support tube 1 21 and the top outer ring of support tube 3 41 are both provided with annular connecting grooves, which are sleeved with support tube 2 31. Support tube 2 31 is connected to support tube 1 21 and support tube 3 41 by bolts; support tube 2 31 is provided with a through hole for wires to pass through, and support tube 2 31 is provided with threaded holes for installing buffer ring 37, connecting ear 1 23 and connecting ear 2 43. The threaded holes are provided with bolts for installation, and the inner ring of buffer ring 37 is provided with a sealing ring that sleeves with support tube 2 31.

[0073] The detection system also includes a control box, which contains a controller. One side of the control box is equipped with a display screen for showing the pressure and flow rate during the detection process. The other side of the controller is equipped with a power interface, a data interface, a switch, and an alarm. The controller is connected to the booster pump 82, pressure gauge 85, pressure control valve 86, exhaust valve 89, flow meter 89, pressure gauge 93, exhaust valve 95, display screen, power interface, data interface, switch, and alarm.

[0074] This invention can more accurately detect the directional pre-splitting effect of bidirectional shaped charge tension blasting on the roof of self-forming roadways without coal pillars, thus providing a basis for further optimizing the parameters of bidirectional shaped charge tension blasting pre-splitting on the roof of self-forming roadways without coal pillars, improving the success rate of pre-splitting on the roof of self-forming roadways without coal pillars, and avoiding the safety risks caused by poor roof cutting effect. It adopts a modular design, which can be assembled by the testing personnel according to the testing needs during the testing process, improving the convenience and adaptability of the testing. It can select components of appropriate length and specifications for assembly according to actual needs, and is suitable for different types of testing needs.

[0075] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for detecting the effect of bidirectional shaped charge tensioning blasting directional pre-splitting of the roof of a self-forming roadway without coal pillars, characterized in that, Includes the following steps: S1. Drill directional pre-splitting boreholes for bidirectional shaped charge tensioning blasting on the roof of the coal mining face at the location of the coal mining roadway. S2. Select and number the directional pre-splitting boreholes for testing; S3. Assemble the detection system for measuring fracture seepage flow; S4. Use a detection system to measure the seepage flow of the original fractures in the borehole wall of the directional pre-splitting borehole, and record the seepage flow data of the original fractures. S5. Perform bidirectional shaped tensioning directional pre-splitting blasting on the top plate of the directional pre-splitting borehole; S6. The seepage flow rate of the directional pre-splitting borehole after blasting is measured using the method in step S4, and the seepage flow rate data of the fracture after blasting is recorded. S7. Determine the effect of bidirectional shaped charge tensioning blasting based on the seepage flow data before and after the blast.

2. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 1, characterized in that, The detection system in step S3 includes a plugging assembly that extends into the directional pre-fractured borehole, as well as a seepage power mechanism and a plugging power mechanism for performing seepage measurement. The plugging assembly includes a top plugging mechanism, a penetration injection mechanism, and a bottom plugging mechanism arranged in sequence.

3. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 2, characterized in that, The permeation power mechanism includes a test bench and a booster pump mounted on top of the test bench. The booster pump has an inlet pipe connected to its inlet and an outlet pipe connected to its outlet. The outlet pipe is equipped with a pressure gauge, a pressure control valve, a valve, an exhaust valve, and a flow meter arranged sequentially. The outlet pipe is used to provide the detection system with a stable pressure permeation medium for permeation detection. The outlet pipe is fixedly connected to a bracket connected to the test bench. The inlet pipe is equipped with a valve.

4. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 2, characterized in that, The sealing power mechanism includes a test bench 2, with a delivery pipe on the top of the test bench 2. The delivery pipe is used to provide the power medium for sealing to the detection system. The delivery pipe is sequentially equipped with a valve 4, a pressure gauge 2, a valve 2, and an exhaust valve 2. The delivery pipe is fixedly connected to a bracket 2 that is connected to the test bench 2.

5. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 2, characterized in that, The top sealing mechanism includes a support tube, a sealing airbag extending downwards is fixedly sleeved on the outer ring of the support tube, a connecting lug is fixedly connected to the bottom inner ring of the sealing airbag along its axis, a connecting air pipe communicating with the sealing airbag is fixedly connected to the inner ring of the support tube, and a connecting pipe that slidably connects to the bottom of the connecting air pipe and is connected to the permeation injection mechanism.

6. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 2, characterized in that, The permeation injection mechanism includes a second support tube that is connected to the top sealing mechanism. A baffle is fixedly connected to the inner ring of the top of the second support tube. A second connecting air tube is fixedly sleeved on the baffle. A diversion hood is provided at the bottom of the baffle and is fixedly sleeved on the inner ring of the second support tube. A spray hole penetrating the second support tube is opened on the outer side of the diversion hood. A feed pipe is provided on the inner side of the diversion hood.

7. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 2, characterized in that, The bottom sealing mechanism includes a support tube three that docks with the permeation injection mechanism. A sealing airbag two with an annular structure is fixedly sleeved on the top outer ring of the support tube three. A connecting lug two distributed along its array is fixedly connected to the top inner ring of the sealing airbag two. A connecting air pipe three is provided on the inner ring of the support tube three. A connecting pipe two that docks with the permeation injection mechanism is slidably sleeved on the top of the connecting air pipe three. A branch pipe communicating with the sealing airbag two is provided on one side of the connecting air pipe three.

8. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 1, characterized in that, In step S5, explosive charge for pre-splitting blasting is buried at the designated location of the directional pre-splitting borehole. The directional pre-splitting borehole is sealed with sealing mud at the opening. Then, the directional pre-splitting borehole is subjected to bidirectional shaped charge tensioning directional pre-splitting blasting on the top plate using explosive charge.

9. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 1, characterized in that, In step S7, the seepage flow rate of the borehole after blasting is compared with the seepage flow rate before blasting. If the seepage flow rate of the borehole after blasting is much greater than that before blasting, the bidirectional shaped charge tension blasting effect is better and the top cutting effect is ideal. In addition, when a large amount of water is detected flowing out of the adjacent borehole, it can also be said that the bidirectional shaped charge tension blasting effect is better.

10. The method for detecting the directional pre-splitting effect of bidirectional shaped charge tensioning blasting on the roof of a self-forming roadway without coal pillars as described in claim 2, characterized in that, The detection system also includes a control box, which contains a controller. A display screen is installed on one side of the control box to show the pressure and flow rate during the detection process.

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