CN110308246B - A technology for eliminating outburst by water injection in outburst coal seam and test method for eliminating outburst effect - Google Patents

Abstract

An outburst elimination technology and outburst elimination effect inspection method by water injection of outburst coal seams are suitable for simulating the outburst elimination technology of outburst coal seam underground outburst coal seam and testing the outburst elimination effect. It includes steps: preliminary preparation stage, outburst inoculation stage, outburst stage before coal seam water injection, coal seam water injection stage, outburst verification stage after coal seam water injection, and outburst elimination effect inspection of coal seam water injection. It can simulate the large-scale outburst coal seam under the coupling conditions of the stress field, seepage field and temperature field, which is closer to the real occurrence state of the outburst coal seam on site; it can carry out water injection and outburst elimination tests of the outburst coal seam under different conditions; The coal seam will further carry out gas outburst test, and check and evaluate the effect of water injection to eliminate outburst according to the test results.

Description

A technology for eliminating outburst by water injection in outburst coal seam and test method for eliminating outburst effect

technical field

The invention relates to a technology for eliminating outburst by water injection in an outburst coal seam and a method for examining the effect of eliminating outburst, and is especially suitable for the technology for eliminating outburst by water injection in a coal mine and a method for examining the effect of eliminating outburst.

Background technique

Coal and gas outburst (abbreviated as outburst) is a violent dynamic process in which the gas-bearing coal rock in the underground coal mine moves sharply (completed within a few seconds to several minutes) from the coal rock layer to the mining space in a pulverized form, accompanied by a large amount of gas ejection. Threat mine safety production. Because it is too dangerous to conduct all-round real-time tracking research on the on-site coal and gas outburst process, most researchers rely on laboratory simulation methods to explore the mechanism of coal and gas outburst by developing corresponding experimental devices.

Water injection into the outburst coal seam can soften the coal seam and reduce the strength of the coal body; at the same time, it can seal the gas inside the matrix block, making it more difficult to convert the gas from the adsorbed state to the free state, that is, increasing the residual amount of coal seam gas and reducing the gas gushing volume. Therefore, water injection into the outburst coal seam can effectively reduce the risk of outburst in theory, and is an effective outburst elimination technology, but it lacks indoor verification.

SUMMARY OF THE INVENTION

In view of the shortcomings of the above technical comparison, a simple structure, good detection effect, simulation of the change of the large-scale outburst coal seam under the coupling conditions of the stress field, seepage field and temperature field is provided, and the outburst coal seam after water injection is further developed. Outburst elimination technology and outburst elimination effect test method of outburst coal seam water injection in gas outburst test.

In order to achieve the above-mentioned technical purpose, the outburst elimination technology and outburst elimination effect inspection method of outburst coal seam water injection of the present invention, an outburst coal seam water injection outburst elimination technology and an outburst elimination effect inspection method, are characterized by comprising: a preliminary preparation stage, an outburst incubation stage, The outburst stage before the coal seam water injection, the coal seam water injection stage, the outburst verification stage after the coal seam water injection, and the coal seam water injection anti-outburst effect test; the specific steps are:

1a) Take samples from the outburst coal seam in the coal mine area to be tested and conduct on-site investigation, use the coal block samples collected on site to measure the relevant parameters of the outburst coal seam, and determine the gas pressure, in-situ stress, water injection hole, water injection rate, water injection time, etc. in the test plan Test parameters;

1b) Use a crushing sieve to sieve the collected coal samples into coal particles with a particle size of 0-1 mm, add water to the coal particles and stir to prepare a 6% moisture content coal sample for later use;

1c) Put the 6% moisture content coal sample into the visual box, the visual box includes the box cavity and the box cover, there is a sealing ring between the box cavity and the box cover and is fixed with sealing bolts, the visual box There are protruding openings on the right side of the visual box, and there are box air inlets at the bottom of the visual box and the outside world. There are multiple transparent loading plates on the top of the visual box and on the left and front side walls of the visual box. The transparent loading plate on the top of the box has six serial numbers X1-X6, the transparent loading plate on the front side wall of the visualization box has six serial numbers Y1-Y6, and the transparent loading plate on the left side wall of the visualization box is Z1, each transparent loading plate is provided with a loading piston, and the loading piston passes through the wall of the box to communicate with the pressurized oil cylinder; the back of the visualization box is provided with a plurality of mounting holes in uniform steps, and the mounting holes of the visualization box are provided with External joint, there is a sealing gasket between the external joint and the box wall of the visual box, and the installation hole is provided with an air pressure sensor, a temperature sensor or a multi-functional drilling as required. The multi-functional drilling includes a sealing section and a ventilation section. The full length of the multi-function drilling is 0.5m, the length of the sealing section is 0.15m, and the length of the ventilation section is 0.35m. There are ventilation holes distributed in the circumferential and radial directions of the pipe wall of the ventilation section. The visualization box uses the installation holes on the back of the visualization box to embed the air pressure sensor into the 6% moisture content coal sample in the visualization box, and finally uses the loading piston to drive the transparent loading plate to make the 6% moisture content coal sample under the condition of 20MPa. After 1h, release the pressure of all transparent loading plates on the coal samples;

1d) Install a momentary protruding door in the protruding opening on the right side of the visualization box, the momentary protruding door includes a bursting disc holder, one end of the bursting disc holder is provided with a mounting flange, and the inside of the bursting disc holder is respectively There are primary bursting discs and secondary bursting discs connected in series. The bursting pressure of primary bursting disc is 0.4/MPa, and the bursting pressure of secondary bursting disc is 0.6/MPa. The bursting disc holder is equipped with a gas source system to inflate the space of the primary and secondary bursting discs until the secondary bursting disc is opened, and at the same time, the primary bursting disc is instantly detonated, so that the protruding opening can be opened instantly, so that the Simulate outburst conditions induced by severe inducing factors such as coal excavation in Shimen;

1e) Seal the cover of the box, connect the high-pressure gas cylinder, vacuum pump, and flowmeter I in sequence. The output end of flowmeter I is connected to the air inlet of the box through a pipeline, and visualize the multi-function serial number A3 at the rear of the box. An external joint is set in the borehole to connect with the flowmeter II, the outlet pipeline of the flowmeter II is connected with the water pump, and the sealing effect of the box and each pipeline is checked;

1f) Install high-speed cameras on the outside of the visualization box and at the momentary protruding door;

2a) Perform triaxial stress loading operation on the coal sample to apply stress to the coal sample: the transparent loading plates with serial numbers X1-X6 on the top of the coal sample are all applied with a stress of 6 MPa, and the six transparent loading plates on the front side with serial numbers Y1-Y6 are all applied with a stress of 6 MPa. The applied stress is 8MPa; the applied stress of a transparent loading plate with serial number Z1 on the left is 10MPa;

2b) Start the vacuum pump to vacuumize the coal sample through the air inlet of the box until the internal pressure of the coal sample is less than 100Pa and then close the vacuum pump, which takes about 12h;

2c) Use a high-pressure gas cylinder to fill the coal sample with gas through the box gas filling port at the bottom of the visual box. It is divided into four stages to ensure that the adsorption equilibrium pressure of the coal sample is 0.74MPa. , then close the gas cylinder and stabilize for 6 hours; in the second stage, inflate for 12 hours, and the inflation pressure reaches 0.6 MPa, then close the gas cylinder and stabilize for 6 hours; in the third stage, inflate for 12 hours, and the inflation pressure reaches 0.74 MPa, then close the gas cylinder and stabilize for 6 hours; Four-stage inflation for 6 hours, inflated and stabilized to 0.74MPa, and then closed the gas cylinder for a total of about 60 hours. During the inflation process, the amount of gas charged was recorded by the flow meter I; at the same time, the high-pressure gas bottle was used to instantly protrude the door. The inflation port between the secondary rupture discs is inflated to 0.3MPa;

3a) Use a high-pressure gas cylinder to inflate the inflation port between the primary and secondary bursting discs of the instantaneously protruding door by inflating more than 0.4 MPa, so that the primary and secondary bursting discs are ruptured successively, thereby simulating gas outbursts in the well;

3b) Use a high-speed camera to collect the images of the pulverized coal ejection in the simulated gas outburst. When the simulated gas outburst ends, stop the stress loading of the transparent loading plate, collect the pulverized coal thrown from the outburst and weigh;

4a) Repeat steps 1c- to 2c, and then use the water pump to inject water into the coal sample through the multifunctional borehole;

5a) After the water injection is completed, use a high-pressure gas cylinder to inflate more than 0.4MPa to the inflation port between the primary and secondary bursting discs of the instantaneously protruding door, so that the primary and secondary bursting discs are ruptured successively to test the protruding whether it happened;

5b) Use a high-speed camera to collect images of pulverized coal ejection in the simulated gas outburst. When the outburst occurs, wait for the end of the outburst, then stop the stress loading of the transparent loading plate, collect the pulverized coal thrown from the outburst and weigh;

6a) Change the test conditions of water injection hole, water injection rate and water injection time in turn, repeat the above test steps to re-test and record relevant information, including:

When using the multifunctional borehole with serial number A3 for water injection, first control the water injection rate to 1.0mL/s, inject water for 2 hours and 5 hours successively for testing, and then inject water successively for 2 hours and 5 hours at a water injection rate of 5.0mL/s to detect;

Or simultaneously inject water into the coal sample by using the multi-function hole numbered A3 and the multi-function hole number A4 at the same time. The two multi-function holes are first controlled at a water injection rate of 1.0 mL/s, and then injected for 2 hours and 5 times. 2 hours and 5 hours for testing, and the water injection rate is 5.0mL/s for 2 hours and 5 hours;

After the above experiments and according to whether it is prominent or the effect of eliminating the protrusion, the best way to eliminate the protrusion is judged.

7a) Calculate the outburst strength before and after the water injection operation according to the mass of the thrown pulverized coal: the mass of the thrown pulverized coal is higher than the total mass of the loaded coal, if no outburst occurs, the outburst strength is recorded as 0;

7b) The outburst strength under different water injection conditions is compared with the outburst strength before water injection to evaluate and test the effect of coal seam water injection. At the same time, the water injection conditions can be further optimized.

The test conditions for changing the water injection hole, water injection rate, and water injection time include:

When using the multifunctional borehole with serial number A3 for water injection, first control the water injection rate to 1.0mL/s, inject water for 2 hours and 5 hours successively for testing, and then inject water successively for 2 hours and 5 hours at a water injection rate of 5.0mL/s to detect;

Or simultaneously inject water into the coal sample by using the multi-function hole numbered A3 and the multi-function hole number A4 at the same time. The two multi-function holes are first controlled at a water injection rate of 1.0 mL/s, and then injected for 2 hours and 5 times. 2 hours and 5 hours for testing, and the water injection rate is 5.0mL/s for 2 hours and 5 hours;

After the above experiments and according to whether it is prominent or the effect of eliminating the protrusion, the best way to eliminate the protrusion is judged.

Beneficial effects:

It can simulate the process of coal seam water injection and outburst elimination under different true triaxial stress and gas pressure multi-field coupling conditions, and simultaneously monitor and collect coal seam gas pressure, temperature, surface crack shape and gas outburst strength, in order to study the outburst under different water injection conditions. The preventive effect and optimization of outburst prevention measures provide effective means.

The advantages of the invention are: (1) It can simulate the large-scale outburst coal seam under the coupling conditions of the stress field, seepage field and temperature field, which is closer to the real occurrence state of the outburst coal seam; (2) It can carry out the outburst coal seam under different conditions. Water injection outburst elimination test; (3) The gas outburst test can be further carried out on the outburst coal seam after water injection, and the water injection outburst elimination effect can be checked and evaluated according to the test results.

Description of drawings:

Fig. 1 is a schematic diagram of the structure of a visual box used for the outburst removal technology of outburst coal seam water injection and the method for testing the effect of removal of outburst.

FIG. 2 is a top view of a visual box used for the outburst elimination technology and the outburst elimination effect inspection method of outburst coal seam water injection according to the present invention.

FIG. 3 is a rear view of a visual box used for the outburst removal technology of outburst coal seam water injection and the method for testing the effect of removal of outburst.

FIG. 4 is a schematic structural diagram of the loading system used by the outburst coal seam water injection and outburst elimination technology and the outburst elimination effect inspection method according to the present invention.

Figure 5(a) is a schematic diagram of the installation of the air pressure sensor used in the water injection outburst elimination technology of the outburst coal seam and the outburst elimination effect inspection method of the present invention.

Figure 5(b) is a schematic diagram of the installation of the temperature sensor used in the outburst coal seam water injection and outburst elimination technology and the outburst elimination effect inspection method of the present invention.

Figure 5(c) is a schematic diagram of the multi-functional drilling installation used in the outburst coal seam water injection and outburst elimination technology and the outburst elimination effect inspection method of the present invention.

FIG. 6 is a schematic diagram of the camera position of the water injection outburst elimination technology and the outburst elimination effect inspection method of the outburst coal seam according to the present invention.

FIG. 7 is a schematic structural diagram of the instantaneous outburst gate used by the water injection outburst elimination technology and the outburst elimination effect inspection method of the present invention.

FIG. 8 is a schematic diagram of the water injection and outburst elimination connection used in the outburst coal seam water injection and outburst elimination technology and the outburst elimination effect inspection method according to the present invention. In the picture: 1-Visual box, 2-Box cavity, 3-Box cover, 4-Protruding port, 5-Sealing ring, 6-Sealing bolt, 7-Box inflation port, 8-Installation hole, 9 -Transparent loading plate, 10-loading piston, 11-air pressure sensor, 12-gasket, 13-PU pneumatic connector, 14-PU tube, 15-data cable, 16-temperature conversion connector, 17-temperature sensor, 18-external connection Joint, 19- Multi-function Drilling, 20- Sealing Section, 21- Ventilation Section, 22- Ventilation Small Hole, 23- High Speed Camera, 24- Momentary Protruding Door, 25- Mounting Flange, 26- Rupture Disc Holder , 27-first-level bursting disc, 28-secondary bursting disc, 29-protruding door inflation port, 30-high pressure gas cylinder, 31-vacuum pump, 32-flowmeter I, 33-flowmeter II, 34-water pump.

specific embodiment

The embodiments of the present invention will be further described below with reference to the accompanying drawings.

As shown in FIG. 1, the outburst elimination technology and outburst elimination effect inspection method of outburst coal seam water injection of the present invention include: preliminary preparation stage, outburst inoculation stage, outburst stage before coal seam water injection, coal seam water injection stage, outburst verification stage after coal seam water injection, and coal seam outburst verification stage. The test of the effect of water injection to eliminate outburst; the specific steps are:

1a) Carry out on-site investigation by sampling the coal blocks of the outburst coal seam in the coal mine area to be tested, and use the coal block samples collected on site to measure the relevant parameters of the outburst coal seam, and determine the gas pressure, in-situ stress, water injection hole, water injection rate, and water injection time in the test plan. and other test parameters;

1b) Use a crushing sieve to sieve the collected coal samples into coal particles with a particle size of 0-1 mm, add water to the coal particles and stir to prepare a 6% moisture content coal sample for later use;

1c) Put the 6% moisture content coal sample into the visual box 1, as shown in Figure 1 and Figure 2, the visual box 1 includes the box cavity 2 and the box cover 3, the box cavity 2 and the box cover There is a sealing ring 5 between 3 and is fixed with sealing bolts 6, a protruding port 4 is opened on the right side of the visualization box 1, and a box air inlet 7 is provided at the bottom of the visualization box 1 and the outside, as shown in Figure 4, the visualization The top of the box body 1 and the left and front side walls of the visualization box body 1 are provided with a plurality of transparent loading plates 9. The transparent loading plates 9 on the top of the visualization box body 1 have six serial numbers X1-X6 respectively. The transparent loading plate 9 on the front side wall of the body 1 has six serial numbers Y1-Y6 respectively. The transparent loading plate 9 on the left side wall of the visualization box 1 is Z1, and each transparent loading plate 9 is provided with a loading piston 10. , the loading piston 10 communicates with the pressurized oil cylinder through the box body wall; as shown in FIG. 3 , the back of the visualization box body 1 is provided with a plurality of mounting holes 8 in a uniform step, wherein the mounting hole 8 of the visualization box body 1 is provided with an external connection The joint 18 is provided with a sealing gasket 12 between the external joint 18 and the box wall of the visualization box 1, and the installation hole 8 is provided with an air pressure sensor 11, a temperature sensor 17 or a multi-function hole 19 as required, and the multi-function hole 19 Including the sealing section 20, the ventilation section 21, the multi-functional drilling 19 is 0.5m long, the sealing section 20 is 0.15m long, the ventilation section 21 is 0.35m long, and the ventilation section 21 has ventilation holes distributed in the circumferential and radial directions of the pipe wall 22. Set the serial numbers to A1-A6 for the multi-function drill holes 19, and use the installation holes 8 opened on the back of the visualization box 1 to bury the 6% moisture content coal samples in the visualization box 1 into the air pressure sensors 11 respectively. , and finally use the loading piston 10 to drive the transparent loading plate 9 to make the coal sample with 6% moisture content under the condition of 20MPa for 1 hour to release the pressure on the coal sample by all the transparent loading plates 9;

As shown in Figure 5(a), the air pressure sensor 11 is inserted into the sensor installation hole 8 outside the visualization box 1 by using the gasket 12, and the end of the air pressure sensor 11 is connected to the data acquisition and control system through the data cable 15. The sensor installation hole 8. There is a PU pipe 14 extending inside the coal sample. The gas pressure at different positions can be tested by adjusting the position of the open end of the PU pipe 14. There is a PU pneumatic joint between the PU pipe 14 and the wall of the visualization box 1. 13;

As shown in Figure 5(b), the data cable 15 connected to the rear of the temperature sensor 17 is fixed in the sensor mounting hole 19 of the visualization box 1 through the adapter 16 and the gasket 12, and the data of the temperature sensor 17 and the head are connected Line 15 is buried in the coal sample where the temperature or stress needs to be detected;

As shown in FIG. 5( c ), a multifunctional drilling hole is arranged in the drilling installation hole, and an external joint is provided on the visual box 1 at the tail of the multifunctional drilling hole, and the external joint is connected to the box wall of the visual box 1 . There is a gasket between them. The multi-functional drilling includes a sealing section 20 and a ventilation section 21. The full length of the multi-functional drilling is 0.5m. There are ventilation holes distributed in the circumferential and radial directions, the diameter of the ventilation holes is 2mm, and the spacing is 5mm.

1d) As shown in FIG. 7, a momentary projection door 24 is installed in the projection opening 4 on the right side of the visualization box 1. The momentary projection door 24 includes a bursting disc holder 26, and one end of the bursting disc holder 26 is installed. There is a mounting flange 25, the inside of the bursting disc holder 26 is respectively provided with a primary bursting disc 27 and a secondary bursting disc 28 connected in series with each other, the bursting pressure of the primary bursting disc 27 is 0.4/MPa, and the secondary bursting disc 28 The bursting pressure is 0.6/MPa, the bursting disc holder 26 between the primary bursting disc 27 and the secondary bursting disc 28 is provided with 29, through the air source system to the primary bursting disc 27 and the secondary bursting disc 28 space Inflate until the secondary bursting disc 28 is opened, and at the same time, the primary bursting disc 27 is detonated instantaneously, so that the outburst opening 4 is instantly opened, so as to simulate the outburst working condition induced by violent inducing factors such as coal excavation in Shimen;

As shown in FIG. 5( a ), an air pressure sensor 11 is arranged in the installation hole 8 , the air pressure sensor 11 is inserted into the sensor installation hole 8 outside the visualization box 1 by using the gasket 12 , and the tail end of the air pressure sensor 11 passes through the data line 15 and The data acquisition is connected to the control system, and a PU pipe 14 extending inside the coal sample is provided inside the sensor installation hole 8. The gas pressure at different positions can be tested by adjusting the position of the open end of the PU pipe 14. The PU pipe 14 is connected to the visualization box 1 A PU pneumatic joint 13 is arranged between the walls of the box;

As shown in FIG. 5( b ), a temperature sensor 17 is set in the installation hole 8 , and the data cable 15 connected to the rear of the temperature sensor 17 is fixed in the sensor installation hole 19 of the visualization box 1 through the adapter 16 and the gasket 12 , bury the temperature sensor 17 and the data line 15 of the head in the coal sample where the temperature or stress needs to be detected;

As shown in FIG. 5( c ), a multi-functional drill hole is arranged in the installation hole 8 , and an external joint is provided on the visual box 1 at the tail of the multi-functional drill hole, and the external joint is connected to the box wall of the visual box 1 There is a gasket between them. The multi-functional drilling includes a sealing section 20 and a ventilation section 21. The multi-functional drilling is 0.5m long, the sealing section 20 is 0.15m long, the ventilation section 21 is 0.35m long, and the ventilation section 21 is around the pipe wall. There are ventilation holes distributed in the radial direction and the diameter of the ventilation holes with a diameter of 2mm and a spacing of 5mm.

1e) As shown in Figure 8, seal the box cover 1, connect the high-pressure gas cylinder 30, vacuum pump 31, and flowmeter I32 in sequence. An external joint 18 is set in the multi-function hole A3 at the rear of the body 1 to be connected to the flowmeter II33, the outlet pipeline of the flowmeter II33 is connected to the water pump 34, and the sealing effect of the box body and each pipeline is detected;

1f) As shown in FIG. 6, high-speed cameras 23 are respectively set on the outside of the visualization box 1 and at the momentary protruding door 24;

2a) Perform triaxial stress loading operation on the coal sample to apply stress to the coal sample: the 6 transparent loading plates 9 with serial numbers X1-X6 on the top of the coal sample are all applied with a stress of 6 MPa, and the 6 transparent loading plates on the front side with serial numbers Y1-Y6 are applied with a stress of 6 MPa. The plates 9 are all applied with a stress of 8MPa; the left transparent loading plate 9 with serial number Z1 is applied with a stress of 10MPa;

2b) Start the vacuum pump 31 to evacuate the coal sample through the air inlet 7 of the box until the internal pressure of the coal sample is less than 100Pa and then close the vacuum pump 31, which takes about 12 hours;

2c) Use the high-pressure gas cylinder 30 to fill the coal sample with gas through the box gas filling port 7 at the bottom of the visual box 1. It is divided into four stages to ensure that the coal sample adsorption equilibrium pressure is 0.74MPa. To 0.3MPa, then close the gas cylinder and stabilize for 6 hours; in the second stage, inflate for 12 hours, and the inflation pressure reaches 0.6MPa, then close the gas cylinder and stabilize for 6 hours; in the third stage, inflate for 12 hours, and the inflation pressure reaches 0.74MPa, then close the gas cylinder and stabilize 6h; in the fourth stage, inflate for 6h, inflate and stabilize to 0.74MPa, and then close the gas cylinder. The total time is about 60h. During the inflation process, the amount of gas charged is recorded by the flow meter I; The inflation port between the primary bursting disc 27 and the secondary bursting disc 28 is inflated to 0.3MPa;

3a) Use the high-pressure gas cylinder 30 to inflate more than 0.4 MPa to the inflation port between the primary bursting disc 27 and the secondary bursting disc 28 of the instantaneously protruding door 24, so that the primary bursting disc 27 and the secondary bursting disc 28 are ruptured successively, thereby Simulate downhole gas outburst;

3b) using the high-speed camera 23 to collect the image of the pulverized coal ejected in the simulated gas outburst, when the simulated gas outburst ends, stop the stress loading of the transparent loading plate 9, collect the pulverized coal thrown out by the protruding port 4 and weigh;

4a) Repeat steps 1c to 2c, and then use the water pump 34 to inject water into the coal sample through the multifunctional borehole;

5a) After the water injection is completed, use the high-pressure gas cylinder 30 to inflate the inflation port between the primary bursting disc 27 and the secondary bursting disc 28 of the instantaneously protruding door 24 by more than 0.4 MPa, so that the primary bursting disc 27 and the secondary bursting disc 28 are inflated by more than 0.4MPa. Rupture successively to test if protrusion occurs;

5b) use the high-speed camera 23 to collect the image of the pulverized coal ejection in the simulated gas outburst, wait for the outburst to end after the outburst occurs, then stop the stress loading of the transparent loading plate 9, collect the pulverized coal thrown by the protruding port 4 and weigh;

6a) Change the test conditions of water injection hole, water injection rate and water injection time in turn, repeat the above test steps to re-test and record relevant information, including:

When using the multifunctional borehole 19 with serial number A3 to inject water, first control the water injection rate to 1.0mL/s, inject water for 2 hours and 5 hours successively for testing, and then inject water for 2 hours and 5 hours at a water injection rate of 5.0mL/s. hours for testing;

Or use the multi-function hole 19 with serial number A3 and the multi-function hole 19 with serial number A4 to inject water into the coal sample at the same time. First, control the water injection rate to 1.0mL/s in the two multi-function holes, and then inject water for 2 hours and 2 hours. 5 hours for testing, and then the water injection rate is 5.0mL/s for 2 hours and 5 hours for testing;

After the above experiments and according to whether it is prominent or the effect of eliminating the protrusion, the best way to eliminate the protrusion is judged.

7a) Calculate the outburst strength before and after the water injection operation according to the mass of the thrown pulverized coal: the mass of the thrown pulverized coal is higher than the total mass of the loaded coal, if no outburst occurs, the outburst strength is recorded as 0;

7b) The outburst strength under different water injection conditions is compared with the outburst strength before water injection to evaluate and test the effect of coal seam water injection. At the same time, the water injection conditions can be further optimized.

Specific test plans include:

Claims (1)

1. An outburst elimination technology and outburst elimination effect inspection method by outburst coal seam water injection, it is characterized in that comprising: preliminary stage preparation stage, outburst inoculation stage, outburst stage before coal seam water injection, coal seam water injection stage, outburst verification stage after coal seam water injection, coal seam water injection elimination stage. Sudden effect test; the specific steps are: 1a) Conduct on-site investigations by sampling the coal blocks of the outburst coal seam in the coal mine area to be tested, and use the coal block samples collected on site to measure the relevant parameters of the outburst coal seam, and determine the gas pressure, in-situ stress, water injection hole, water injection rate, and water injection time in the test plan. parameter; 1b) Use a crushing sieve to sieve the collected coal samples into coal particles with a particle size of 0-1 mm, add water to the coal particles and stir to prepare a 6% moisture content coal sample for use; 1c) Put the 6% moisture content coal sample into the visual box. The visual box includes the box cavity and the box cover. There is a sealing ring between the box cavity and the box cover and is fixed with sealing bolts. The visual box There are protruding openings on the right side of the visual box, and there are box air inlets at the bottom of the visual box and the outside world. There are multiple transparent loading plates on the top of the visual box and on the left and front side walls of the visual box. The transparent loading plate on the top of the box has six serial numbers X1-X6, the transparent loading plate on the front side wall of the visualization box has six serial numbers Y1-Y6, and the transparent loading plate on the left side wall of the visualization box is Z1, each transparent loading plate is provided with a loading piston, and the loading piston passes through the box wall and communicates with the pressurized oil cylinder; a plurality of installation holes are evenly arranged on the back of the visualization box, and an external joint is arranged on the installation holes of the visualization box , There is a sealing gasket between the external joint and the box wall of the visual box, and the installation hole is provided with a pressure sensor, a temperature sensor or a multi-functional drilling as required. The multi-functional drilling includes a sealing section, a ventilation section, and a multi-functional drilling. The total length of the drilling hole is 0.5 m, the length of the sealing section is 0.15 m, and the length of the ventilation section is 0.35 m. There are ventilation holes distributed in the circumferential and radial directions of the pipe wall of the ventilation section. The 6% moisture content coal samples in the visualization cabinet were respectively embedded with air pressure sensors using the installation holes on the back of the visualization cabinet, and finally the 6% moisture content coal samples were formed under the condition of 20 MPa by using the loading piston to drive the transparent loading plate. After h, release the pressure of all transparent loading plates on the coal sample; 1d) Install a momentary protruding door in the protruding opening on the right side of the visualization box. The momentary protruding door includes a bursting disc holder, one end of the bursting disc holder is provided with a mounting flange, and the inside of the bursting disc holder is respectively There are primary bursting discs and secondary bursting discs connected in series. The bursting pressure of primary bursting disc is 0.4/MPa, and the bursting pressure of secondary bursting disc is 0.6/MPa. The bursting disc holder is provided with a protruding door inflatable port, and the air supply system is used to inflate between the primary bursting disc and the secondary bursting disc until the secondary bursting disc is opened, and at the same time, the primary bursting disc is instantly detonated to realize the protruding opening. Instantaneously open to simulate the outburst condition induced by violent inducing factors such as Shimen coal opening; 1e) Seal the cover of the box, connect the high-pressure gas cylinder, vacuum pump, and flowmeter I in sequence. The output end of flowmeter I is connected to the air inlet of the box through a pipeline, and visualize the multi-function serial number A3 at the rear of the box. An external joint is set in the borehole to connect with the flowmeter II, the outlet pipeline of the flowmeter II is connected with the water pump, and the sealing effect of the box and each pipeline is checked; 1f) Install high-speed cameras on the outside of the visualization box and at the momentary protruding door; 2a) Perform triaxial stress loading operation on the coal sample to apply stress to the coal sample: the 6 transparent loading plates numbered X1-X6 on the top of the coal sample are all applied with a stress of 6 MPa, and the 6 transparent loading plates numbered Y1-Y6 on the front side The stress of 8 MPa is applied to all boards; the stress of 10 MPa is applied to the transparent loading board with the serial number Z1 on the left; 2b) Start the vacuum pump to evacuate the coal sample through the air inlet of the box until the internal pressure of the coal sample is less than 100Pa, and then close the vacuum pump, which takes 12 hours; 2c) Use a high-pressure gas cylinder to charge the coal sample through the gas filling port at the bottom of the visual box. It is divided into four stages to ensure that the equilibrium pressure of the coal sample adsorption is 0.74 MPa. MPa, then close the gas cylinder, and stabilize for 6 hours; in the second stage, inflate for 12 hours, and the inflation pressure reaches 0.6 MPa, then close the gas cylinder, and stabilize for 6 hours; in the third stage, inflate for 12 hours, and the inflation pressure reaches 0.74 MPa, and then close the gas cylinder , stabilized for 6 hours; the fourth stage was inflated for 6 hours, inflated and stabilized to 0.74 MPa, and then closed the gas cylinder for a total of 60 hours. During the inflation process, the amount of gas charged was recorded by the flow meter I; The inflation port between the primary and secondary bursting discs of the door is inflated to 0.3 MPa; 3a) Use a high-pressure gas cylinder to inflate the gas filling port between the primary and secondary bursting discs of the instantaneously protruding door by more than 0.4MPa, so that the primary and secondary bursting discs rupture successively, thereby simulating gas outbursts in the well; 3b) Use a high-speed camera to collect the images of pulverized coal ejection in the simulated gas outburst. When the simulated gas outburst ends, stop the stress loading of the transparent loading plate, collect the pulverized coal thrown from the outburst and weigh; 4a) Repeat steps 1c- to 2c, and then use the water pump to inject water into the coal sample through the multifunctional borehole; 5a) After the water injection is completed, use a high-pressure gas cylinder to inflate more than 0.4 MPa to the inflation port between the first-level bursting disc and the second-level bursting disc of the instantaneously protruding door, so that the first-level bursting disc and the second-level bursting disc are ruptured successively to test the protruding whether it happened; 5b) Use a high-speed camera to collect images of pulverized coal ejection in the simulated gas outburst. When the outburst occurs, wait for the end of the outburst, then stop the stress loading of the transparent loading plate, collect the pulverized coal thrown from the outburst and weigh it; 6a) Change the test conditions of the water injection hole, water injection rate, and water injection time in turn. Repeat all the above test steps to re-test and record the relevant information, including: When using the multifunctional borehole with serial number A3 for water injection, first control the water injection rate to 1.0mL/s, inject water for 2 hours and 5 hours successively for testing, and then inject water successively for 2 hours and 5 hours at a water injection rate of 5.0mL/s to detect; Or simultaneously inject water into the coal sample by using the multi-function hole numbered A3 and the multi-function hole number A4 at the same time. The two multi-function holes are first controlled at a water injection rate of 1.0 mL/s, and then injected for 2 hours and 5 times. 2 hours and 5 hours for testing, and the water injection rate is 5.0mL/s for 2 hours and 5 hours; After the above experiments and according to whether it is prominent or the effect of eliminating the burst, the best way to eliminate the burst is judged; 7a) Calculate the outburst strength before and after the water injection operation according to the mass of the thrown pulverized coal: the mass of the thrown pulverized coal is higher than the total mass of the loaded coal. If no outburst occurs, the outburst strength is recorded as 0; 7b) The outburst strength under different water injection conditions is compared with the outburst strength before water injection to evaluate and test the effect of coal seam water injection. At the same time, the water injection conditions were further optimized.

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