A coal seam working face cutting eye and chute hydraulic fracturing construction method

Abstract

The invention discloses a coal seam working face cutting eye and hydraulic fracturing construction method for the chute, and relates to the field of coal mining. The invention comprises the following steps: a, arranging three groups of fracturing holes in the cutting eye orientation; b, constructing three groups of fracturing holes in two chute; c, cleaning the borehole and determining the position of the pre-crack; d, installing and connecting the hole sealer, debugging the high-pressure water pump, sealing the hole, and injecting water for fracturing; e, manually pumping the hole sealer to ensure that the hole sealer maintains pressure normally; f, turning on the hydraulic pressure gauge, turning on the water and electricity of the high-pressure water pump, slowly pressurizing until the pre-crack cracks, and injecting water to maintain pressure to allow the crack to continue to expand; g, after the fracturing is completed, the high-pressure water pump is powered off and the water is cut off, and the hole sealer is depressurized and withdrawn; h, repeating steps c-g, injecting water for fracturing one by one, and observing each fracturing hole. The hydraulic fracturing construction method provided by the invention optimizes and improves the drilling angle and depth, effectively recovers the top coal, and improves the resource recovery efficiency. It is a new construction method for weakening the roof during the initial mining and initial release of the fully-mechanized caving working face.

Description

Technical Field

[0001] The invention relates to the field of coal mining, in particular to a roof weakening construction method during initial mining and initial caving of a fully-mechanized caving working face, specifically a coal seam working face cutting eye and drift hydraulic fracturing construction method. Background Art

[0002] In the existing coal mine, a coal seam is mined by longwall and comprehensive mechanized top coal caving technology, and the roof is managed by the full span method. The machine mining height of the working face is 2.6m, the top coal caving thickness is 1.3m, the mining and caving ratio is 2:1, the cycle progress is 0.6m, and the "one mining and one caving" process is adopted. According to the description in the top coal caving design of the existing fully mechanized working face, during the initial mining and caving, the initial collapse step distance of the direct roof is 12~18m. After the support is pushed out of the cut eye 8m, once there is a partial collapse of the direct roof, the top coal can be caved to ensure the recovery rate of coal. However, according to the actual production situation, without taking any other measures, during the initial mining and caving, after the support is pushed out of the cut eye 8m, there is no sign of collapse at all on the direct roof, and top coal cannot be caved.

[0003] Taking the I section of a fully mechanized caving face that has been mined as an example, during the initial mining and initial caving period, after the support was pushed out of the cutting eye for about 35m, the direct roof showed signs of local collapse, and the top coal could be caved, resulting in about 27m of top coal not being effectively recovered, causing a waste of resources. The coal resources wasted during the initial mining and initial caving period of the I section of the fully mechanized caving face can be calculated as follows:

[0004] Q cycle = L2 × h × S × γ × C2 × 27

[0005] =131.8×1.3×0.6×1.43×85%×27

[0006] =3373.87t

[0007] Where:

[0008] L2——top coal caving length, m, take 131.8m;

[0009] h——coal seam thickness, m, working face mining height h1=2.6m, coal caving height h2=1.3m;

[0010] S——cycle progress, 0.6m;

[0011] γ——raw coal bulk density, 1.43t / m3;

[0012] C2——top coal recovery rate of working face, 85%.

[0013] On the other hand, the goaf has a large hanging roof area, and the initial mine pressure is severe, which brings great pressure to safe production. Summary of the invention

[0014] In order to solve the problems that during the initial mining and initial release, the support is pushed out to cut the top directly without any signs of collapse, and top coal cannot be released. Top coal is not released until collapse occurs, resulting in serious waste of resources, and the goaf has a large hanging roof area, and the initial mining and initial release of the mine pressure is serious, which poses a certain risk to production safety. Hydraulic fracturing measures are taken to weaken the roof, and the design of hydraulic fracturing holes is continuously optimized and improved. The present invention provides a coal seam working face cutting and drift hydraulic fracturing construction method.

[0015] The present invention is implemented by the following technologies:

[0016] A coal seam working face cutting and chute hydraulic fracturing construction method designed by the present invention comprises the following steps:

[0017] a. Use a fully hydraulic tunnel drill for coal mines to perform fracturing drilling construction, using a Φ75mm drill bit and a Φ50mm drill rod, and arrange three groups of fracturing holes in the cut-eye orientation, namely, fracturing hole H, fracturing hole S, and fracturing hole L. The fracturing holes H are arranged in a single row in the top plate of the cut-eye, 1 meter away from the old mountain wall, and the direction is parallel to the cut-eye, that is, all the fracturing holes H are on the same longitudinal section, and the section is parallel to the vertical plane where the coal mining working face is located. The fracturing holes H face the direction of the cut-eye. Wind-smoothed slot, drilling elevation angle of 45 degrees, hole depth of 20 meters, hole spacing of 10 meters; fracturing hole S is located at the upper edge of the coal wall in the cut, and its direction is perpendicular to the upper edge of the coal wall in the cut, facing the coal wall, drilling elevation angle of 35 degrees, hole depth of 24 meters; fracturing hole L is located at the upper edge of the coal wall in the cut, and its direction is perpendicular to the upper edge of the coal wall in the cut, facing the coal wall, drilling elevation angle of 25 degrees, hole depth of 33 meters, fracturing hole S and fracturing hole L are staggered, and the hole spacing is 10 meters;

[0018] b. Use a fully hydraulic tunnel drill for coal mines for fracturing drilling construction, using a Φ75mm drill bit and a Φ50mm drill rod. Construct three groups of fracturing holes in the two drifts 60 meters from the cutout to the outside, namely, fracturing hole HI, fracturing hole SⅠ, and fracturing hole LⅠ. Fracturing hole HI is arranged in a single row 1 meter away from the coal pillar along the tunnel. The first hole of fracturing hole HI is arranged 10 meters away from the cutout. There are 6 holes in each of the two tunnels, and a total of 12 holes in the two drifts. The direction of fracturing hole HI is parallel to the tunnel, that is, all fracturing holes HI are on the same longitudinal section, and the section is parallel to the tunnel. Fracturing hole HI faces the old mountain wall, with an elevation angle of 45 degrees, a hole depth of 20 meters, and a hole spacing of 10 meters; fracturing hole SⅠ Ⅰ The first hole is arranged 10 meters away from the cut-eye, 3 holes are arranged in each of the two lanes, and there are 6 holes in total in the two drifts. The fracturing hole SⅠ is arranged along the upper edge of the coal wall in the lane, and its direction is perpendicular to the upper edge of the coal wall in the lane, facing the coal wall. The drilling angle of the fracturing hole SⅠ is 35 degrees, and the hole depth is 24 meters; The first hole of the fracturing hole LⅠ is arranged 10 meters away from the first fracturing hole SⅠ, 3 holes are arranged in each of the two lanes, and there are 6 holes in total in the two drifts. The fracturing hole LⅠ is arranged along the upper edge of the coal wall in the lane, and its direction is perpendicular to the upper edge of the coal wall in the lane, facing the coal wall. The drilling angle is 25 degrees, and the hole depth is 33 meters. The fracturing hole SⅠ and the fracturing hole LⅠ are staggered, and the distance between adjacent fracturing holes SⅠ and fracturing holes LⅠ is 10 meters;

[0019] c. Clean the borehole with hydrostatic water and use a peephole to peer into the borehole to determine the location of the pre-cracks;

[0020] d. Install and connect the hole sealer, connect static pressure water to exhaust and pressure test the hole sealer to ensure normal operation, connect the connected manual pump and accumulator to the hole sealer through a high-pressure hose, and use an O-ring seal at the connection. The connection adopts a quick connection method. The motor power of the high-pressure water pump is 90KW. Choose a high-pressure water pump equipped with an explosion-proof switch. The water inlet of the high-pressure water pump is connected to static pressure water, and the water outlet is connected to a high-pressure hose with a pressure of 80MPa. The connection between the high-pressure hose and the water outlet of the high-pressure water pump adopts an A-type buckle connection method. The other end of the high-pressure hose is connected to the water injection steel pipe. The connection adopts a quick connection method, and the connection is sealed with an O-ring. Check the connection, first pass water through the high-pressure water pump and then power it on, adjust the forward and reverse rotation, and complete the connection and debugging of the high-pressure water pump; connect the water injection steel pipe to push the hole sealer to the pre-crack, seal the hole, and use the reverse fracturing method for water injection fracturing;

[0021] e. The distance between the operator and the operating equipment and the fracturing hole is more than 20m. The manual pump pressurizes the sealer. When the pressure reaches 10-15MPa, stop pressurizing. Observe the borehole and monitor the pressure gauge. If the pressure reading is stable and the sealer maintains pressure, it is working normally.

[0022] f. Turn on the water pressure gauge, first pass water through the high-pressure water pump and then turn on the power, slowly increase the pressure, and record the data of the high-pressure water pump pressure gauge, flow meter and manual pump pressure gauge at the same time. Continue to increase the pressure until the pre-cracks crack. At this time, the pressure will suddenly drop, and the pressure-maintaining water injection will continue to expand the cracks. The pressure-maintaining water injection fracturing time is determined according to the on-site fracturing situation and should be more than 30 minutes. Transverse cracks are formed along the crack direction. If water seeps out or emerges from the tunnel roof, coal seam or borehole during the process, stop fracturing immediately;

[0023] g. After the fracturing is completed, the high-pressure water pump is first powered off and then the water is cut off, the sealer is depressurized, the borehole is exited, and the fracturing effect is observed using a peep instrument;

[0024] h, repeat the above steps cg, inject water for fracturing one by one and observe each fracturing hole drilled in steps ab.

[0025] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a coal seam working face cutting and chute hydraulic fracturing construction method, adopts hydraulic fracturing measures to weaken the roof, and continuously optimizes and improves the design of hydraulic fracturing holes, reasonably increases the number of hydraulic fracturing holes on the working face side in the cutting and working face chute, and optimizes and improves the drilling angle and depth. In the hydraulic fracturing drilling hole layout design, hydraulic fracturing holes S and hydraulic fracturing holes L are used to weaken the roof on the one hand and the coal body on the other hand. Since the fracturing holes away from the hole mouth are located within the coal body, the coal body is simultaneously fractured during the fracturing process, resulting in many cracks and releasing the mine pressure. During the initial mining and caving process, as soon as the rear tail beam of the support leaves the cutting range and before the direct roof collapses on a large scale, the top coal can be caved quickly, timely and effectively, effectively recovering the top coal and avoiding waste of resources. This improves the efficiency of resource recovery and forms a set of effective roof weakening construction methods during the initial mining and caving of the fully mechanized top caving working face. It can be widely used in the recovery of underground fully mechanized top caving working faces and is a new roof weakening construction method during the initial mining and caving of fully mechanized top caving working faces. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A plan view showing the arrangement of hydraulic fracturing drilling holes for the working face cut in the present invention.

[0027] Figure 2 A plan view showing the arrangement positions of hydraulic fracturing drilling holes in two chutes of the working face in the present invention.

[0028] Figure 3 It shows a vertical cross-sectional view of the hydraulic fracturing borehole S of the working face cut in the present invention.

[0029] Figure 4 It shows a vertical cross-sectional view of the hydraulic fracturing borehole L of the working face cut in the present invention.

[0030] Figure 5A vertical cross-sectional view of the hydraulic fracturing borehole H of the working face cut in the present invention is shown.

[0031] Figure 6 It shows the vertical cross-section of hydraulic fracturing borehole SⅠ in two chute of the working face in the present invention.

[0032] Figure 7 A vertical cross-sectional view of hydraulic fracturing boreholes LI in two chute of the working face in the present invention is shown.

[0033] Figure 8 It shows the vertical cross-section of hydraulic fracturing boreholes HI in two chute of the working face in the present invention.

[0034] In the figure: 1- fracturing hole H, 2- fracturing hole S, 3- fracturing hole L, 4- cut-eye, 5- chute, 6- fracturing hole HI, 7- fracturing hole SⅠ, 8- fracturing hole LⅠ, 9- coal body. DETAILED DESCRIPTION

[0035] The specific embodiments of the present invention are described below in conjunction with the accompanying drawings.

[0036] A coal seam working face cutting and chute hydraulic fracturing construction method designed by the present invention comprises the following steps:

[0037] a. The drilling and fracturing construction in cut 4 are carried out from the return air side to the air inlet side in sequence. The ZDY1250 type coal mine fully hydraulic tunnel drilling rig is used for fracturing drilling construction, using a Φ75mm drill bit and a Φ50mm drill rod. Figure 1 , 5 As shown, three groups of fracturing holes are arranged in the cut hole 4, namely, fracturing hole H1, fracturing hole S2, and fracturing hole L3. Figure 5 As shown, the fracturing holes H1 are arranged in a single row in the top plate of the cut eye 4, 1 meter away from the old mountain wall, and the direction is parallel to the cut eye 4, that is, all the fracturing holes H1 are on the same longitudinal section, and the section is parallel to the vertical plane where the coal mining working face is located. The fracturing holes H1 face the air inlet chute, the drilling elevation angle is 45 degrees, the hole depth is 20 meters, and the hole spacing is 10 meters. The fracturing holes H1 are not subjected to fracturing construction within 10-15 meters from the hole mouth to ensure the integrity and safety of the support in the cut eye 4; Figure 3 As shown, the fracturing hole S2 is located at the upper edge of the coal wall in the cut hole 4, and its direction is perpendicular to the upper edge of the coal wall in the cut hole 4, facing the coal wall, with a drilling elevation angle of 35 degrees and a hole depth of 24 meters; Figure 4As shown, the fracturing hole L3 is located at the upper edge of the coal wall side in the cut eye 4, and its direction is perpendicular to the upper edge of the coal wall side in the cut eye 4, facing the coal wall, the drilling elevation angle is 25 degrees, the hole depth is 33 meters, the fracturing holes S2 and the fracturing holes L3 are staggered, and the hole spacing is 10 meters. The fracturing hole L3 can weaken the roof, cut off the direct roof and old roof (sandstone) in the cut eye 4, so that the roof can collapse in time during the initial mining and initial release. The fracturing holes S2 and the fracturing holes L3 are fractured to the hole mouth. On the one hand, the two can weaken the roof. On the other hand, since the fracturing holes away from the hole mouth are located within the coal body 9 of the coal seam, the coal body 9 can be fractured at the same time during the re-fracturing process, and many cracks are generated in the coal body 9, ensuring that the top coal can be quickly and timely released during the initial mining and initial release, thereby improving the resource recovery efficiency.

[0038] b. The drilling and fracturing construction of the two tunnels were carried out gradually from the inside to the outside as the mining progressed. The ZDY1250 type coal mine fully hydraulic tunnel drilling rig was used for fracturing drilling construction, using a Φ75mm drill bit and a Φ50mm drill rod. Figure 2 At the position, three groups of fracturing holes are constructed in the two drifts 5 from the cut-eye 4 to 60 meters away, namely, fracturing hole HⅠ6, fracturing hole SⅠ7, and fracturing hole LⅠ8. Figure 2 , 8 As shown, the fracturing holes HI6 are arranged in a single row along the tunnel at a distance of 1 meter from the coal pillar. The first fracturing hole HI6 is arranged at a distance of 10 meters from the cut hole 4. Six holes are arranged in each of the two tunnels, and a total of 12 holes are arranged in the two drifts 5. Figure 8 As shown, the direction of the fracturing hole HI6 is parallel to the roadway, that is, all the fracturing holes HI6 are on the same longitudinal section, and the section is parallel to the roadway. The fracturing hole HI6 faces the old mountain, with an elevation angle of 45 degrees, a hole depth of 20 meters, and a hole spacing of 10 meters; Figure 6 As shown, the first fracturing hole SⅠ7 is arranged at a distance of 10 meters from the cut-eye 4, and three holes are arranged in each of the two lanes, and a total of six holes are arranged in the two drifts 5. The fracturing hole SⅠ7 is arranged along the upper edge of the coal wall in the lane, and the direction is perpendicular to the upper edge of the coal wall in the lane, facing the coal wall. The drilling angle of the fracturing hole SⅠ7 is 35 degrees, and the hole depth is 24 meters; Figure 7 As shown, the first fracturing hole LⅠ8 is arranged at 10 meters of the first fracturing hole SⅠ7, 3 holes are arranged in each of the two lanes, and the two drifts 5 have a total of 6 holes. The fracturing hole LⅠ8 is arranged along the upper edge of the coal wall in the lane, and the direction is perpendicular to the upper edge of the coal wall side in the lane, facing the coal wall, the drilling elevation angle is 25 degrees, and the hole depth is 33 meters. The fracturing hole SⅠ7 and the fracturing hole LⅠ8 are staggered, and the hole spacing between adjacent fracturing holes SⅠ7 and fracturing holes LⅠ8 is 10 meters. The fracturing holes SⅠ7 and fracturing holes LⅠ8 are fracturing to the hole mouth. On the one hand, the two can weaken the roof, and on the other hand, because the fracturing holes away from the hole mouth are located within the coal body 9 of the coal seam, the coal body 9 can be fractured at the same time during the re-fracturing process, and many cracks are generated in the coal body 9, ensuring that the top coal can be quickly and timely released during the initial mining and initial release, thereby improving the resource recovery efficiency;

[0039] c. Clean the borehole with hydrostatic water and use a peephole to peer into the borehole to determine the location of the pre-cracks;

[0040] d. Install and connect the hole sealer, connect static pressure water to exhaust and pressure test the hole sealer to ensure normal operation, connect the connected manual pump and accumulator to the hole sealer through a high-pressure hose, and use an O-ring seal at the connection, and use a quick connection method; the motor power of the high-pressure water pump is 90KW, and a high-pressure water pump equipped with an explosion-proof switch is selected. The water inlet of the high-pressure water pump is connected to static pressure water, and the water outlet is connected to a high-pressure hose with a pressure of 80MPa. The connection between the high-pressure hose and the water outlet of the high-pressure water pump adopts an A-type buckle connection method, and the other end of the high-pressure hose is connected to the water injection steel pipe. The connection adopts a quick connection method and an O-ring seal at the connection. Check the connection, first pass water through the high-pressure water pump and then power it on, adjust the forward and reverse rotation, and complete the connection and debugging of the high-pressure water pump; connect the water injection steel pipe to push the hole sealer to the pre-crack to seal the hole. The water injection fracturing adopts a reverse fracturing method, that is, fracturing is carried out from the bottom of the borehole to the outside in sequence to solve the problem of dense outside and sparse inside during fracturing;

[0041] e. The distance between the operator and the operating equipment and the fracturing hole is more than 20m, the supporting conditions are good, and the manual pump pressurizes the sealer. When the pressure reaches 10-15MPa, stop pressurizing, observe the borehole and monitor the pressure gauge. If the pressure indicator is stable and the sealer maintains pressure, it is normal operation. If water flows out of the borehole or the pressure drops significantly, it means that the sealer has failed. Check the various connections of the sealer and the sealer itself, find and solve the problem, and ensure that the sealer can maintain pressure and work normally;

[0042] f. Turn on the water pressure gauge, first pass water through the high-pressure water pump and then turn on the power, slowly increase the pressure, and record the data of the high-pressure water pump pressure gauge, flow meter and manual pump pressure gauge at the same time. Continue to increase the pressure until the pre-cracks crack. At this time, the pressure will suddenly drop, and the pressure-maintaining water injection will continue to expand the cracks. The pressure-maintaining water injection fracturing time is determined according to the on-site fracturing situation and should be more than 30 minutes. Transverse cracks are formed along the crack direction. If water seeps out or emerges from the tunnel roof, coal seam or borehole during the process, stop fracturing immediately;

[0043] g. After the fracturing is completed, the high-pressure water pump is first powered off and then the water is cut off, the sealer is depressurized, the borehole is exited, and the fracturing effect is observed using a peep instrument;

[0044] h, repeat the above steps cg, inject water for fracturing one by one and observe each fracturing hole drilled in steps ab.

[0045] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A coal seam working face cutting and chute hydraulic fracturing construction method, characterized in that: The following steps are involved: a. Use a fully hydraulic tunnel drill for coal mines to perform fracturing drilling construction. Arrange three groups of fracturing holes in the direction of the cut-eye (4), namely, fracturing hole H (1), fracturing hole S (2), and fracturing hole L (3). The fracturing holes H (1) are arranged in a single row in the top plate of the cut-eye (4) at a distance of 1 meter from the old mountain wall, parallel to the cut-eye (4), toward the wind inlet trough, with a drilling elevation angle of 45 degrees, a hole depth of 20 meters, and a hole spacing of 10 meters; the fracturing holes S (2) are arranged in a single row in the top plate of the cut-eye (4) at a distance of 1 meter from the old mountain wall, parallel to the cut-eye (4), and toward the wind inlet trough, with a drilling elevation angle of 45 degrees, a hole depth of 20 meters, and a hole spacing of 10 meters; the fracturing holes S (3) are arranged in a single row in the top plate of the cut-eye (4) at a distance of 1 meter from the old mountain wall, parallel to the cut-eye (4), and toward the wind inlet trough, (2) located at the upper edge of the coal wall in the cut hole (4), with a direction perpendicular to the upper edge of the coal wall in the cut hole (4), facing the coal wall, with a drilling elevation angle of 35 degrees and a hole depth of 24 meters; the fracturing hole L (3) located at the upper edge of the coal wall in the cut hole (4), with a direction perpendicular to the upper edge of the coal wall in the cut hole (4), facing the coal wall, with a drilling elevation angle of 25 degrees and a hole depth of 33 meters, and the fracturing hole S (2) and the fracturing hole L (3) are staggered, with a hole spacing of 10 meters; b. Use a fully hydraulic tunnel drill for coal mines to perform fracturing drilling construction. Construct three groups of fracturing holes in the two drifts (5) 60 meters outward from the cut-out (4), namely, fracturing hole HI (6), fracturing hole SⅠ (7), and fracturing hole LⅠ (8). The fracturing holes HI (6) are arranged in a single row along the tunnel 1 meter away from the coal pillar. The first hole of the fracturing holes HI (6) is arranged 10 meters away from the cut-out (4). Six holes are arranged in each of the two tunnels, and a total of 12 holes are arranged in the two drifts (5). The direction of the fracturing holes HI (6) is parallel to the tunnel, facing the old mountain wall, with an elevation angle of 45 degrees, a hole depth of 20 meters, and a hole spacing of 10 meters; the first hole of the fracturing holes SⅠ (7) is arranged 10 meters away from the cut-out (4). Three holes are arranged in each of the two tunnels. Holes, a total of 6 holes in the two drifts (5), the fracturing hole SⅠ (7) is arranged along the upper edge of the coal wall in the tunnel, and its direction is perpendicular to the upper edge of the coal wall in the tunnel, facing the coal wall, the drilling angle of the fracturing hole SⅠ (7) is 35 degrees, and the hole depth is 24 meters; the first hole of the fracturing hole LⅠ (8) is arranged 10 meters away from the first fracturing hole SⅠ (7), and 3 holes are arranged in each of the two tunnels, a total of 6 holes in the two drifts (5), the fracturing hole LⅠ (8) is arranged along the upper edge of the coal wall in the tunnel, and its direction is perpendicular to the upper edge of the coal wall in the tunnel, facing the coal wall, the drilling angle is 25 degrees, and the hole depth is 33 meters, the fracturing hole SⅠ (7) and the fracturing hole LⅠ (8) are staggered, and the distance between adjacent fracturing holes SⅠ (7) and fracturing holes LⅠ (8) is 10 meters; c. Clean the borehole with hydrostatic water and use a peephole to peer into the borehole to determine the location of the pre-cracks; d. Install and connect the hole sealer, debug the high-pressure water pump, connect the water injection steel pipe, push the hole sealer to the pre-crack, seal the hole, and use the reverse fracturing method for water injection fracturing; e. The distance between the operator and the operating equipment and the fracturing hole is more than 20m. The manual pump pressurizes the sealer. When the pressure reaches 10-15MPa, stop pressurizing. Observe the borehole and monitor the pressure gauge. If the pressure reading is stable and the sealer maintains pressure, it is working normally. f. Turn on the water pressure gauge, first pass water through the high-pressure water pump and then turn on the power, slowly increase the pressure, and record the data of the high-pressure water pump pressure gauge, flow meter and manual pump pressure gauge at the same time. Continue to increase the pressure until the pre-cracks crack. At this time, the pressure will suddenly drop, and the pressure-maintaining water injection will continue to expand the cracks. The pressure-maintaining water injection fracturing time is determined according to the on-site fracturing conditions, and transverse cracks are formed along the crack direction; g. After the fracturing is completed, the high-pressure water pump is first powered off and then the water is cut off, the sealer is depressurized, the borehole is exited, and the fracturing effect is observed using a peep instrument; h, repeat the above steps cg, inject water for fracturing one by one and observe each fracturing hole drilled in steps ab.

2. A coal seam working face cutting and chute hydraulic fracturing construction method according to claim 1, characterized in that: The specific steps for installing the hole sealer in step d are: connect the hole sealer, connect static pressure water to vent and pressure test the hole sealer to ensure normal operation, connect the connected manual pump and accumulator to the hole sealer through a high-pressure hose, use an O-ring to seal the connection, and use a quick connection method.

3. A coal seam working face cutting and chute hydraulic fracturing construction method according to claim 1, characterized in that: The specific steps for debugging the high-pressure water pump in step d are as follows: the high-pressure water pump should be equipped with an explosion-proof switch, the water inlet of the high-pressure water pump is connected to static pressure water, and the water outlet is connected to a high-pressure hose with a pressure of 80MPa. The connection between the high-pressure hose and the water outlet of the high-pressure water pump adopts an A-type crimping connection method, and the other end of the high-pressure hose is connected to a water injection steel pipe. The connection adopts a quick connection method, and the connection is sealed with an O-ring. Check the connection, first pass water through the high-pressure water pump and then power it on, adjust the forward and reverse rotation, and complete the connection and debugging of the high-pressure water pump.

4. A coal seam working face cutting and chute hydraulic fracturing construction method according to claim 1, characterized in that: In step f, the pressure-maintaining water injection fracturing time should be more than 30 minutes. If water seeps or emerges from the tunnel roof, coal seam or borehole during the process, fracturing should be stopped immediately.

5. A coal seam working face cutting and chute hydraulic fracturing construction method according to claim 1, characterized in that: In step a and step b, the fracturing drilling uses a Φ75mm drill bit and a Φ50mm drill rod.

6. A coal seam working face cutting and chute hydraulic fracturing construction method according to claim 1 or 3, characterized in that: The power of the high-pressure water pump motor used in step d is 90KW.

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