CN105891429B - The coal and gas prominent analogue means and test method of repeatable experiment - Google Patents

Abstract

The invention discloses a repeatable test coal and gas outburst simulation device, which comprises a protruding cylinder body, a Z-direction piston connected to the top of the protruding cylinder body, and an X- and Y-direction cylinder body connected to the bottom of the protruding cylinder body; the side wall of the protruding cylinder body The middle part is connected with the first pipeline, and the first pipeline is connected with the second pipeline and the third pipeline in parallel; the first pressure gauge is installed on the first pipeline; the second pipeline is connected with a high-pressure gas tank; the third pipeline It is connected with the suction port of a vacuum pump; the Y-direction cylinder is connected with a Y-direction piston, and the top wall of the Y-direction cylinder is provided with a coal charging port; the X-direction cylinder is connected with an X-direction piston, and the X-direction cylinder is connected with a top wall A protruding opening is provided; a fourth pipeline is connected to the bottom wall of the X-direction cylinder. The invention also discloses a test method using the above-mentioned simulation device. In a word, the present invention can simulate the natural gushing process of gas before the outburst, and simulate the influence of the thickness of the front coal body on the outburst, which is closer to the field conditions; the present invention can load a coal sample and repeat multiple tests, which improves the test efficiency.

Description

Repeatable test coal and gas outburst simulation device and test method

technical field

The invention relates to a coal and gas outburst simulation device for studying the occurrence law and mechanism of coal mine gas disasters, which is suitable for coal and gas outburst simulation tests under various conditions.

Background technique

The coal and gas outburst accident in the underground coal seam of coal mine is a complex dynamic disaster phenomenon caused by the combined effects of in-situ stress, gas pressure and coal physical and mechanical properties, which has always threatened the safe production of coal mines. In order to study the mechanism of coal and gas outburst and provide theoretical support for the control of coal mine gas disasters, people have long been committed to the theoretical and experimental research on the mechanism of coal and gas outburst. As early as 1953, Khodot VV and others of the former Soviet Union used CO ₂ and outburst-prone coal for the first time in the world to successfully realize the simulation test of coal and gas outburst in the laboratory, and thus started the coal and gas outburst The study of law and its mechanism. However, more than 60 years have passed, and up to now, the mechanism of coal and gas outburst has not been clarified, and it is still in a hypothesis stage, which shows the complexity of the research on the mechanism of coal and gas outburst.

In my country, research on coal and gas outburst simulation experiments started relatively late. In 1989, Deng Quanfeng and others from the Fushun Branch of the Coal Research Institute developed a one-dimensional coal and gas outburst simulation test device, and gained some useful insights. Afterwards, China University of Mining and Technology, Institute of Mechanics, Chinese Academy of Sciences, Henan University of Technology, Anhui University of Science and Technology, Chongqing University, China Coal Science and Industry Group Chongqing Research Institute Co., Ltd., etc. have successively developed a model that can simulate various experimental conditions and is suitable for different coal sample sizes. The coal and gas outburst simulation test equipment has been developed, and a series of test research results have been obtained.

The above-mentioned domestic and foreign related experimental research has greatly promoted the development of the theory related to the mechanism of coal and gas outburst, but there are still some problems and deficiencies in the simulated test device developed:

(1) Poor repeatability. In the past outburst simulation process, coal and gas outburst experiments can only be done once with a coal sample, even if the outburst experiment is unsuccessful, coal samples must be loaded again, the steps are cumbersome and the experiment period is long.

(2) It is difficult to truly simulate the outburst process of underground coal seams. The actual coal and gas outbursts in coal mines are started and completed under an open system, that is, coal and gas accidents occur in the process of gas gushing out from coal seams. At present, when simulating coal and gas outburst, all test devices are always in a closed system state before the outburst occurs (that is, the gas is completely sealed before the outburst is opened to prevent it from gushing out), and only when the outburst is opened The gas gushes out in an instant, and this treatment method is contrary to the open system where gas gushes out on site.

(3) The influence of the thickness of the front coal body on the outburst cannot be simulated. All the current simulation devices are unable to simulate the influence of the thickness of the coal body in front of the outburst on the outburst. In reality, when outbursts occur in underground coal mines, there is always a certain thickness of coal ahead. If all the conditions for outburst have been satisfied somewhere in the coal seam, but the thickness of the coal body in front is too large, and the outburst energy in the coal seam cannot overcome the resistance brought by the front coal body, no outburst accident will occur.

Because it is impossible to more realistically simulate the real situation, it is still difficult to figure out the mechanism of coal and gas outburst using the existing coal and gas outburst simulation test equipment, so the mechanism of coal and gas outburst is still in the hypothetical stage.

Contents of the invention

The purpose of the present invention is to provide a coal and gas outburst simulation device that can be tested repeatedly. The outburst test can be completed under an open system, and multiple outburst tests can be performed after loading a coal sample, and can simulate the influence of the thickness of the coal body ahead on the outburst. .

In order to achieve the above object, the repeatable test coal and gas outburst simulation device of the present invention takes the two directions perpendicular to each other in the horizontal direction as the X direction and the Y direction respectively, and takes the vertical direction as the Z direction;

It includes a protruding cylinder set along the vertical direction. The top of the protruding cylinder is provided with an opening and is connected with a Z-direction piston. The Z-direction piston is in sliding and sealing connection with the inner side wall of the protruding cylinder. The piston rod of the Z-direction piston protrudes upwards from the protruding cylinder. ;The bottom of the protruding cylinder is connected with an X-direction cylinder and a Y-direction cylinder;

An opening is provided in the middle of the side wall of the protruding cylinder, and the opening is connected with a first pipeline, and the first pipeline is connected with a second pipeline and a third pipeline in parallel; a first pressure gauge is provided on the first pipeline;

The second pipeline is connected with a high-pressure gas tank, the second pipeline is provided with a second pressure gauge, and the second pipeline at the outlet of the high-pressure gas tank is provided with a first valve and a pressure reducing valve;

The end of the third pipeline is connected with the suction port of a vacuum pump, and the third pipeline is provided with a second valve;

The inner wall of the Y-direction cylinder is connected with a Y-direction piston with a sliding seal. The piston rod of the Y-direction piston protrudes from the free end of the Y-direction cylinder along the axis of the Y-direction cylinder. The top wall of the Y-direction cylinder is provided with a coal charging port. ;

The inner wall of the X-direction cylinder is slidingly sealed with an X-direction piston, the piston rod of the X-direction piston protrudes from the free end of the X-direction cylinder along the axis of the X-direction cylinder, and the top wall of the X-direction cylinder is provided with a protrusion;

The top wall of the X-direction cylinder is provided with a third pressure gauge, the bottom wall of the X-direction cylinder is provided with an air release port, the air release port is connected to a fourth pipeline, and a third valve and a flow meter are arranged in turn on the fourth pipeline , the end of the fourth line is open.

A fourth valve is arranged on the second pipeline, and the second pressure gauge is located on the second pipeline between the pressure reducing valve and the fourth valve.

The protruding opening protrudes upwards from the top wall of the Z-direction cylinder.

The object of the present invention is also to provide a test method using the above-mentioned coal and gas outburst simulation device which can be tested repeatedly.

In order to achieve the above object, the test method of the present invention is carried out according to the following steps successively:

(1) Open the fourth valve and the first valve, close the second valve and the third valve, fill the protruding cylinder with gas gas, then close the fourth valve and the first valve, and observe the reading of the first pressure gauge to determine The airtightness of the simulation device; if there is an air leak, check the leak point and carry out plugging treatment. If the airtightness of the simulation device is good, perform step (2);

(2) Pull the Z-direction piston upwards from the protruding cylinder, and put the granular coal powder into the simulation device through the opening on the top of the protruding cylinder, the coal charging port and the protruding port; the coal powder in the X-direction cylinder is used for Simulate the thickness of the coal body in front of the outburst on site;

(3) Use the Z-piston, Y-piston and X-piston to apply load to the pulverized coal, and press the pulverized coal into a coal sample;

(4) Open the second valve and start the vacuum pump to devacuumize the coal sample.

(5) After the vacuum treatment is completed, close the vacuum pump and the second valve, open the fourth valve and the first valve, start filling the coal sample with gas, adjust the pressure reducing valve, and reduce the pressure of the gas filled into the coal sample. Adjusted to the predetermined value of the simulation test;

(6) Let the coal sample fully adsorb under the predetermined gas pressure conditions, and make it reach the adsorption-desorption equilibrium; the method for judging that the coal sample has reached the adsorption-desorption equilibrium is:

After the coal sample absorbs gas for 10-14 hours, close the first valve and the fourth valve;

After 2 hours, if the readings of the first pressure gauge and the third pressure gauge are equal, it indicates that the coal sample has reached the adsorption-desorption equilibrium, and at this time step (7) is performed;

After 2 hours, if the readings of the first pressure gauge and the third pressure gauge are not equal, it indicates that the coal sample has not reached the equilibrium of adsorption and desorption, and re-execute step (5);

(7) After the coal sample reaches the equilibrium of adsorption and desorption, keep the fourth valve and the first valve open, and open the third valve connected to the gas release port to let the gas flow out naturally to simulate the natural gas flow before the on-site outburst occurs. During the gas discharge process, monitor the dynamic change process of the gas emission through the flowmeter; keep the X-direction piston stationary, use the Z-direction piston to apply a vertical load to the coal sample to the specified load and stop loading, and use the Y-direction piston to apply a vertical load to the coal sample. Stop loading after the horizontal load reaches the specified load size;

(8) Use the control cylinder to move the X-direction piston to the free end of the X-direction cylinder until the coal sample is connected to the protrusion; if the coal sample is connected to the protrusion and a protrusion occurs, the test is successful;

If no outburst occurs after the coal sample is connected to the outburst, it indicates that the applied load has not reached the outburst critical value under the current test conditions;

At this time, the X-direction piston can be re-pushed to the position between the protrusion and the protrusion cylinder by controlling the oil cylinder, so that the test can be repeated without reloading and unloading the coal sample, that is, step (9);

(9) Change the load and/or gas pressure, repeat the above steps (1) to (8), and obtain the critical value of outburst stress and outburst gas pressure under specific test conditions.

The present invention has following advantage:

In the outburst simulation test, compared with the previous similar test devices, the present invention can simulate the natural gushing process of the gas before the outburst, and can simulate the influence of the thickness of the front coal body on the outburst, so the present invention is closer to the field practice conditions, can accurately simulate the outburst process on site, study the laws and phenomena of coal and gas outburst more realistically and reliably, provide a reliable experimental basis for the study of the occurrence mechanism of coal and gas outburst, and guide the production practice of coal mines. The invention can load a coal sample once and repeat multiple tests, greatly improves the test efficiency, saves the test time and the labor intensity required by the test.

The present invention is provided with load application functions in the vertical direction and the horizontal direction, which can simulate the combined conditions of the self-weight stress and the horizontal structural stress of the overlying strata in the coal seam, and carry out the coal and gas outburst experiment under this combination condition, and can accurately obtain the coal and gas outburst Initiation conditions of stress, including stress onset conditions and gas pressure onset conditions.

The invention can simulate the influence of different coal thicknesses on coal and gas outburst, and a gas release port is provided in the direction of the outburst to simulate the open environment where gas naturally gushes out before the outburst occurs, and more realistically simulates the outburst condition.

After the coal sample is loaded once, the coal and gas outburst experiments can be repeated many times, with good repeatability. Realized the repetitive function of "loading a coal sample and doing multiple outstanding experiments", which improved the efficiency of equipment use, shortened the experiment cycle, and improved work efficiency.

Description of drawings

Fig. 1 is the main view structure schematic diagram of the coal and gas outburst simulation device of the present invention that can repeat the test;

Fig. 2 is the left view structure schematic diagram of the repeatable test coal and gas outburst simulation device of the present invention;

Fig. 3 is a top view structure schematic diagram of the repeatable test coal and gas outburst simulation device of the present invention.

detailed description

In the present invention, the two directions perpendicular to each other in the horizontal direction are respectively the X direction and the Y direction, and the vertical direction is the Z direction.

As shown in Fig. 1, Fig. 2 and Fig. 3, the repeatable test coal and gas outburst simulation device of the present invention includes a protruding cylinder 1 arranged in the vertical direction, and the top of the protruding cylinder 1 is provided with an opening and is connected with a Z direction Piston 2, Z-direction Piston 2 is slidingly and sealingly connected with the inner wall of the protruding cylinder 1, the piston rod of the Z-direction piston 2 protrudes upwards from the protruding cylinder 1; the bottom of the protruding cylinder 1 is connected with the X-direction cylinder 21 and the Y-direction cylinder 20;

There is an opening in the middle of the side wall of the protruding cylinder 1, and the opening is connected with a first pipeline 31, and the first pipeline 31 is connected in parallel with a second pipeline 32 and a third pipeline 33; a pressure gauge 11;

The second pipeline 32 is connected with a high-pressure gas tank 7, the second pipeline 32 is provided with a second pressure gauge 10, and the second pipeline 32 at the outlet of the high-pressure gas tank 7 is provided with a first valve 15 and a pressure reducing valve 9;

The end of the third pipeline 33 is connected with the suction port of a vacuum pump 8, and the third pipeline 33 is provided with a second valve 14;

The inner wall of the Y-direction cylinder 20 is connected with the Y-direction piston 3 in sliding seal, the piston rod of the Y-direction piston 3 protrudes from the free end of the Y-direction cylinder 20 along the axial direction of the Y-direction cylinder 20, and the top of the Y-direction cylinder 20 The wall is provided with a coal charging port 5;

The inner wall of the X-direction cylinder 21 is slidingly and sealedly connected with the X-direction piston 4, and the piston rod of the X-direction piston protrudes from the free end of the X-direction cylinder 21 along the axial direction of the X-direction cylinder 21, and the top wall of the X-direction cylinder 21 provided with a protruding opening 18;

The top wall of the X-direction cylinder 21 is provided with a third pressure gauge 12, and the bottom wall of the X-direction cylinder 21 is provided with an air release port 17, and the air release port 17 is connected with a fourth pipeline 34, and the fourth pipeline 34 is sequentially A third valve 16 and a flow meter 19 are provided; the end of the fourth pipeline 34 is open.

The second pipeline 32 is provided with a fourth valve 13 , and the second pressure gauge 10 is located on the second pipeline 32 between the pressure reducing valve 9 and the fourth valve 13 .

The protruding opening 18 protrudes upward toward the top wall of the cylinder 21 .

The present invention also discloses a test method using the above-mentioned repeatable test coal and gas outburst simulation device, which is carried out in sequence as follows:

(1) Open the fourth valve 13 and the first valve 15, close the second valve 14 and the third valve 16, fill the protruding cylinder 1 with gas, then close the fourth valve 13 and the first valve 15, observe the The reading of a pressure gauge 11 is used to determine the airtightness of the simulation device of the present invention; if there is an air leak, check the leak point and carry out the plugging process, and if the airtightness of the simulation device is good, then perform the (2) step ;

(2) Pull the Z-direction piston 2 upwards from the protruding cylinder 1, through the opening at the top of the protruding cylinder 11, the coal charging port 5 and the protruding port 18, put the sieved coal powder into the cylinder of the present invention. A simulation device; the pulverized coal in the X-direction cylinder 21 is used to simulate the thickness of the coal body in front of the on-site protrusion;

(3) Use the Z-direction piston 2, the Y-direction piston 3 and the X-direction piston 4 to apply a load to the pulverized coal, and press the pulverized coal into a coal sample 6;

(4) Open the second valve 14 and start the vacuum pump 8 to devacuumize the coal sample 6 .

(5) After the devacuum treatment is completed, close the vacuum pump 8 and the second valve 14, open the fourth valve 13 and the first valve 15, start filling the coal sample 6 with gas, adjust the pressure reducing valve 9, and fill the coal sample The pressure of the gas in 6 is adjusted to the predetermined value of the simulation test;

(6) Allow coal sample 6 to fully adsorb under predetermined gas pressure conditions, and make it reach the adsorption-desorption equilibrium; the method for judging that coal sample 6 has reached the adsorption-desorption equilibrium is:

After the coal sample absorbs gas for 10-14 hours (the specific time is determined by the test personnel based on experience, 12 hours is used at most), the first valve 15 and the fourth valve 13 are closed;

After 2 hours, if the readings of the first pressure gauge 11 and the third pressure gauge 12 are equal, it indicates that the coal sample 6 has reached the adsorption-desorption equilibrium, and step (7) is performed at this time;

After 2 hours, if the readings of the first pressure gauge 11 and the third pressure gauge 12 are not equal, it indicates that the coal sample 6 has not reached the adsorption-desorption equilibrium, and re-execute step (5);

(7) After the coal sample 6 reaches the equilibrium of adsorption and desorption, keep the fourth valve 13 and the first valve 15 in the open state, and open the third valve 16 connected to the gas release port 17 to let the gas flow out naturally to simulate the scene before the outburst occurs During the natural gas gushing process, monitor the dynamic change process of the gas gushing amount through the flow meter 19; keep the X-direction piston 4 stationary, and use the Z-direction piston 2 to apply a vertical load to the coal sample 6 to the specified load size and then stop loading , use the Y-to-piston 3 to apply a horizontal load to the coal sample 6 to a specified load size and then stop loading;

(8) Use the control cylinder to move the X-direction piston 4 to the free end of the X-direction cylinder 21 until the coal sample 6 communicates with the protruding port 18 (that is, open the protruding port 18); Prominent phenomenon, the test is successful;

If there is no outburst after the coal sample 6 is connected with the overhang 18, it indicates that the applied load has not reached the outburst critical value under the current test conditions;

At this time, the piston 4 can be pushed to the position between the protruding port 18 and the protruding cylinder body 1 again by controlling the oil cylinder, that is, the protruding port 18 is closed, so that the test can be repeated without reloading and unloading the coal sample 6, that is, Go to step (9);

(9) Change the load and/or gas pressure, repeat the above steps (1) to (8), and obtain the critical value of outburst stress and outburst gas pressure under specific test conditions.

The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced without departing from it. Any modifications or partial replacements within the spirit and scope of the present invention shall fall within the scope of the claims of the present invention.

Claims (4)

1. The coal and gas outburst simulation device that can be tested repeatedly is characterized in that: the two directions perpendicular to each other in the horizontal direction are respectively the X direction and the Y direction, and the vertical direction is the Z direction; It includes a protruding cylinder set along the vertical direction. The top of the protruding cylinder is provided with an opening and is connected with a Z-direction piston. The Z-direction piston is in sliding and sealing connection with the inner side wall of the protruding cylinder. The piston rod of the Z-direction piston protrudes upwards from the protruding cylinder. ;The bottom of the protruding cylinder is connected with an X-direction cylinder and a Y-direction cylinder; An opening is provided in the middle of the side wall of the protruding cylinder, and the opening is connected with a first pipeline, and the first pipeline is connected with a second pipeline and a third pipeline in parallel; a first pressure gauge is provided on the first pipeline; The second pipeline is connected with a high-pressure gas tank, the second pipeline is provided with a second pressure gauge, and the second pipeline at the outlet of the high-pressure gas tank is provided with a first valve and a pressure reducing valve; The end of the third pipeline is connected with the suction port of a vacuum pump, and the third pipeline is provided with a second valve; The inner wall of the Y-direction cylinder is connected with a Y-direction piston with a sliding seal. The piston rod of the Y-direction piston protrudes from the free end of the Y-direction cylinder along the axis of the Y-direction cylinder. The top wall of the Y-direction cylinder is provided with a coal charging port. ; The inner wall of the X-direction cylinder is slidingly sealed with an X-direction piston, the piston rod of the X-direction piston protrudes from the free end of the X-direction cylinder along the axis of the X-direction cylinder, and the top wall of the X-direction cylinder is provided with a protrusion; The top wall of the X-direction cylinder is provided with a third pressure gauge, the bottom wall of the X-direction cylinder is provided with an air release port, the air release port is connected to a fourth pipeline, and a third valve and a flow meter are arranged in turn on the fourth pipeline , the end of the fourth line is open. 2. The repeatable testable coal and gas outburst simulation device according to claim 1, characterized in that: the second pipeline is provided with a fourth valve, and the second pressure gauge is located at the first place between the pressure reducing valve and the fourth valve. On the second pipeline. 3. The repeatable testable coal and gas outburst simulation device according to claim 1 or 2, characterized in that: the protruding opening protrudes upwards from the top wall of the Z-direction cylinder. 4. use the test method of the coal and gas outburst simulator described in claim 3, it is characterized in that following the steps successively: (1) Open the fourth valve and the first valve, close the second valve and the third valve, fill the protruding cylinder with gas gas, then close the fourth valve and the first valve, and observe the reading of the first pressure gauge to determine The airtightness of the simulation device; if there is an air leak, check the leak point and carry out plugging treatment. If the airtightness of the simulation device is good, perform step (2); (2) Pull the Z-direction piston upwards from the protruding cylinder, and put the granular coal powder into the simulation device through the opening on the top of the protruding cylinder, the coal charging port and the protruding port; the coal powder in the X-direction cylinder is used for Simulate the thickness of the coal body in front of the outburst on site; (3) Use the Z-piston, Y-piston and X-piston to apply load to the pulverized coal, and press the pulverized coal into a coal sample; (4) Open the second valve and start the vacuum pump to devacuumize the coal sample; (5) After the vacuum treatment is completed, close the vacuum pump and the second valve, open the fourth valve and the first valve, start filling the coal sample with gas, adjust the pressure reducing valve, and reduce the pressure of the gas filled into the coal sample. Adjusted to the predetermined value of the simulation test; (6) Let the coal sample fully adsorb under the predetermined gas pressure conditions, and make it reach the adsorption-desorption equilibrium; the method for judging that the coal sample has reached the adsorption-desorption equilibrium is: After the coal sample absorbs gas for 10-14 hours, close the first valve and the fourth valve; After 2 hours, if the readings of the first pressure gauge and the third pressure gauge are equal, it indicates that the coal sample has reached the adsorption-desorption equilibrium, and at this time step (7) is performed; After 2 hours, if the readings of the first pressure gauge and the third pressure gauge are not equal, it indicates that the coal sample has not reached the equilibrium of adsorption and desorption, and re-execute step (5); (7) After the coal sample reaches the equilibrium of adsorption and desorption, keep the fourth valve and the first valve open, and open the third valve connected to the gas release port to let the gas flow out naturally to simulate the natural gas flow before the on-site outburst occurs. During the gas discharge process, monitor the dynamic change process of the gas emission through the flowmeter; keep the X-direction piston stationary, use the Z-direction piston to apply a vertical load to the coal sample to the specified load and stop loading, and use the Y-direction piston to apply a vertical load to the coal sample. Stop loading after the horizontal load reaches the specified load size; (8) Use the control cylinder to move the X-direction piston to the free end of the X-direction cylinder until the coal sample is connected to the protrusion; if the coal sample is connected to the protrusion and a protrusion occurs, the test is successful; If no outburst occurs after the coal sample is connected to the outburst, it indicates that the applied load has not reached the outburst critical value under the current test conditions; At this time, the X-direction piston can be re-pushed to the position between the protrusion and the protrusion cylinder by controlling the oil cylinder, so that the test can be repeated without reloading and unloading the coal sample, that is, step (9); (9) Change the load and/or gas pressure, repeat the above steps (1) to (8), and obtain the critical value of outburst stress and outburst gas pressure under specific test conditions.