Gas-containing coal dynamic experiment system and method with controllable impact frequency and equivalent weight

Abstract

The invention discloses a gas-containing coal dynamic experiment system and method with controllable impact frequency and equivalent weight, and relates to the technical field of coal seam mining, and the gas-containing coal dynamic experiment system comprises an intelligent servo control driving device, a guide rail, a slide rail, a punch carrying device, a spindle-shaped punch, a steel impact gasket, an incident rod, a transmission rod, an absorption rod and a multi-field coupling experiment device, the intelligent servo control driving device intelligently controls a sliding rail installed on the guide rail through program assignment so as to drive the punch carrying device and the spindle-shaped punch in the punch carrying device to do reciprocating motion, the steel impact gasket can be impacted at different impact frequencies and equivalents, and the central axis of the steel impact gasket, the central axis of the incidence rod, the central axis of the transmission rod and the central axis of the absorption rod are collinear. Through the intelligent servo control driving device, the impact loading frequency and the impact equivalent can be automatically adjusted through program control, the preset impact parameters can be output, the accuracy and the consistency of impact loading are improved, and the experiment requirements under different impact conditions are met.

Description

Technical Field

[0001] This invention relates to the field of coal seam mining technology, and in particular to a dynamic experimental system and method for gas-bearing coal with controllable impact frequency and equivalent. Background Technology

[0002] In recent years, in the fields of deep mineral resource mining and underground engineering construction, the study of the dynamic characteristics of gas-bearing coal under dynamic loads has been of great significance for preventing geological disasters such as rockbursts and gas outbursts. In actual occurrence environments, coal bodies are often subjected to a combination of static loads (such as ground stress) and dynamic loads (such as blasting disturbances and mechanical impacts), accompanied by the migration and seepage of gas. Their mechanical behavior and gas evolution law exhibit significant multi-field coupling characteristics. Therefore, simulating the dynamic response of gas-bearing coal under combined static and dynamic loading conditions through experimental means has become a key technical support for revealing the mechanism of disaster occurrence and optimizing engineering prevention and control measures.

[0003] Currently, the traditional one-dimensional dynamic-static combined loading test system is widely used in experimental systems for studying the dynamic characteristics of gas-bearing coal. The working principle of this type of system is that nitrogen in a high-pressure gas chamber drives a spindle-shaped punch, which then collides head-on with the end face of the incident rod after obtaining a certain impact velocity. This generates a stress pulse at the front end of the incident rod. The amplitude of the stress pulse depends on the impact velocity of the punch. The stress wave propagates in the incident rod and undergoes transmission and reflection at the contact interface between the incident rod and the sample, and between the sample and the transmission rod. Finally, the incident wave, reflected wave, and transmitted wave pulse are recorded by a transient waveform memory to analyze the dynamic characteristics of the sample. However, traditional one-dimensional dynamic-static combined loading test systems have many limitations. First, they lack the ability to control impact parameters, with uncontrollable impact frequency and unstable impact velocity, making it difficult to precisely adjust the amplitude of stress pulses and meet the experimental requirements under different impact conditions, thus affecting the repeatability and reliability of experimental results. Second, they lack the function of monitoring gas-related parameters, making it impossible to obtain real-time information on changes in gas pressure and flow rate during the impact process, and making it difficult to study the work done by gas expansion and the evolution of permeability during dynamic impact. For the special research object of gas-bearing coal, the analysis of relevant dynamic characteristics is not comprehensive enough. Third, the simulation scenario is limited, only able to realize stress wave propagation tests under one-dimensional stress conditions, and cannot simulate the complex conditions of multiple factors such as confining pressure, temperature, and axial static load on gas-bearing coal in the actual underground environment. The experimental environment differs greatly from the actual engineering scenario, resulting in limited engineering reference value of the experimental results. Fourth, the standardization of experimental operation and the comprehensiveness of data acquisition need to be improved. The traditional system operation process is relatively simple, and the data acquisition is mainly focused on the transient waveform of stress waves. The acquisition and analysis of key information such as the mechanical response characteristics of gas-bearing coal and gas-related parameters are insufficient, making it difficult to explore the dynamic behavior of gas-bearing coal in depth. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the problems existing in the prior art, the present invention provides a dynamic experimental system and method for gas-bearing coal with controllable impact frequency and equivalent.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent, comprising an intelligent servo control drive device, a guide rail, a slide rail, a punch carrying device, a spindle-shaped punch, a steel impact pad, an incident rod, a transmission rod, an absorption rod, and a multi-field coupling experimental device. The intelligent servo control drive device intelligently controls the slide rail mounted on the guide rail through program assignment to drive the punch carrying device and the internal spindle-shaped punch to reciprocate, achieving impacts on the steel impact pad with different impact frequencies and equivalents. The central axes of the steel impact pad, the incident rod, the transmission rod, and the absorption rod are collinear. A multi-field coupling experimental device is provided between the incident rod and the transmission rod. The multi-field coupling experimental device is equipped with a gas injection pipeline interface, a confining pressure loading pipeline interface, a temperature control liquid input pipeline interface, and a temperature control liquid output pipeline interface. Strain gauges are attached to the incident rod and the transmission rod, respectively. The strain gauges are connected to an ultra-dynamic strain gauge via twisted-pair cables and are connected to an oscilloscope recorder and a data processor.

[0008] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, the guide rails on both sides are parallel to each other, and the guide rails on the same side are connected by bolts and steel bars of the same length. The guide rails are embedded in the slide rails to ensure that the slide rails always slide along the prescribed route.

[0009] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, the slide rail and the punch carrying device are connected by a bolt-hinge support, and the system also includes a positioning groove. The positioning groove is used to calibrate the position of the slide rail in order to correct the equivalent error caused by long-term high-frequency impact.

[0010] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, the punch carrying device is embedded with an embedded high-elastic rubber pad to ensure that the spindle-shaped punch is stable during launch and collides concentrically with the steel impact pad.

[0011] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, the gas injection pipeline interface is internally connected to a snap-fit ​​sealing adapter and connected to a heat shrink tubing, and the sample is installed in the heat shrink tubing between the incident rod and the transmission rod.

[0012] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, the gas injection pipeline interface is connected to an adapter valve via an external pipeline. The adapter valve is connected to the vacuum pump pipeline control valve and then to the vacuum pump. It is also connected to the tail gas treatment pipeline control valve and then to the tail gas treatment device. A high-frequency gas pressure gauge is connected to the tail gas flow meter, and the gas injection pipeline control valve is connected to the methane high-pressure cylinder.

[0013] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, the confining pressure loading pipeline interface is connected to a digital display confining pressure loading pump via an external confining pressure loading pipeline control valve.

[0014] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, it further includes a temperature-controlled compressor. When the temperature-controlled compressor is working, it opens the control valve of the temperature-controlled liquid output pipeline. The temperature-controlled liquid input pipeline is connected to the temperature-controlled liquid input pipeline interface in the multi-field coupling experimental device. The liquid flows through the temperature-controlled liquid pipeline to the temperature-controlled liquid output pipeline interface in the multi-field coupling experimental device to achieve heat transfer temperature control. It also includes a temperature digital display sensor for real-time recording of the liquid temperature, and the liquid temperature is stabilized to the set temperature.

[0015] As a preferred embodiment of the gas-containing coal dynamics experimental system with controllable impact frequency and equivalent as described in this invention, it further includes a digital display axial pressure loading pump. The digital display axial pressure loading pump is connected to the axial pressure loading pipeline control valve through a pipeline and is connected to the axial pressure loading chamber for applying axial static load.

[0016] A dynamic experimental method for gas-bearing coal with controllable impact frequency and equivalent includes the following steps:

[0017] S1. Apply Vaseline to both ends of the sample and place them in heat shrink tubing. Align the two ends of the sample with the axes of the incident rod and the transmission rod, respectively, to keep the sample sealed and isolated from the hydraulic oil in the multi-field coupling experimental device.

[0018] S2. Open the axial pressure loading pipeline control valve and slowly pressurize hydraulic oil into the axial pressure loading chamber through the digital display axial pressure loading pump to apply axial pressure to the sample in the multi-field coupling experimental device. When the preset axial load of the test is reached, close the axial pressure loading pipeline control valve.

[0019] S3. Close all control valves of the external devices of the multi-field coupling experimental setup, and only open the vacuum pump pipeline control valve to start the vacuum pump for evacuation until the high-frequency pressure gauge stabilizes at a constant negative pressure, then close the vacuum pump pipeline control valve.

[0020] S4. Open the confining pressure loading pipeline control valve and slowly pressurize hydraulic oil into the multi-field coupling experimental device through the digital display axial pressure loading pump; when the pre-set confining pressure is reached, close the confining pressure loading pipeline control valve.

[0021] S5. Open the high-pressure methane cylinder and the gas injection pipeline control valve. At this time, the gas from the high-pressure methane cylinder will be injected along the pipeline between the injection rod and the transmission rod, and onto the sample inside the heat shrink tube. When the preset gas pressure value is reached, immediately close the gas injection pipeline control valve, and then the coal body enters the gas adsorption step.

[0022] S6. Open the control valve of the temperature control liquid output pipeline, turn on the temperature control compressor and set the liquid output temperature. Heat transfer is carried out through the temperature control liquid pipeline. The temperature digital display sensor records the liquid temperature change in real time. When the output temperature is consistent with the set temperature and the gas pressure of the high-frequency gas pressure gauge is stable, close the control valve of the temperature control liquid output pipeline and enter the preparation stage before the impact test.

[0023] S7. Turn on the ultra-dynamic strain gauge, oscilloscope recorder, data processor and infrared timer. Also, set the timer to store data according to the acquisition frequency.

[0024] S8. After setting the impact frequency and impact equivalent, turn on the intelligent servo control drive device and start the transmission switch of the intelligent servo control drive device to conduct the impact test of gas-containing coal. At this time, the stress wave is transmitted to the coal and rock sample through the incident rod, then to the transmission rod through the sample, and finally to the absorption rod.

[0025] S9. After the impact test of each sample is completed, open the control valve of the exhaust gas treatment pipeline to perform gas exhaust gas treatment.

[0026] S10. Process the data collected during the impact process, including stress wave curves, gas pressure and flow rate changes, and analyze the mechanical response characteristics of gas-bearing coal, the work done by gas expansion, and permeability characteristics.

[0027] (III) Beneficial Effects

[0028] This invention provides a dynamic experimental system and method for gas-bearing coal with controllable impact frequency and equivalent. It has the following beneficial effects:

[0029] 1. Through the intelligent servo control drive device, the impact loading frequency and impact equivalent can be automatically adjusted by program control without human intervention. It can stably output the preset impact parameters, which greatly improves the accuracy and consistency of impact loading and meets the experimental needs under different impact conditions.

[0030] 2. By setting up a gas injection pipeline and matching high-frequency gas pressure gauge and high-frequency gas flow meter, the gas pressure and flow can be monitored and stored in real time throughout the impact process, providing key data for calculating the work done by gas expansion during dynamic impact and analyzing the evolution of permeability.

[0031] 3. This device can not only realize impact loading, but also integrate functions such as confining pressure loading, temperature control, and axial static load application. Through the multi-field coupling experimental device, a complex environment containing multiple factors such as gas, confining pressure, temperature, and axial force is constructed. It can more realistically simulate the stress and environmental state of gas-bearing coal under actual underground conditions, making the experimental results more valuable for engineering reference.

[0032] 4. The experimental methods of this device have standardized procedures from sample installation and multi-parameter loading to impact testing and exhaust gas treatment. The data acquisition covers various aspects such as stress wave curves, gas pressure and flow rate changes. At the same time, through equipment such as ultra-dynamic strain gauges, oscilloscope recorders, and data processors, real-time recording and timed storage of data can be realized, which facilitates subsequent comprehensive analysis of the mechanical response characteristics, gas expansion work and permeability characteristics of gas-bearing coal, thus improving the utilization rate and analysis depth of experimental data.

[0033] 5. Through functions such as axial compression loading, confining pressure loading, and temperature control, the axial static load, confining pressure, and ambient temperature of the sample can be precisely controlled. Combined with the stable control of the gas adsorption process, the sample is in a preset stable state before impact, reducing the interference of environmental factors on the experimental results and further ensuring the reliability of the experiment. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0036] Figure 2 This is a cross-sectional view of the experimental device for multi-field coupling of three-dimensional dynamic and static loads, gas, and temperature in this invention.

[0037] Figure 3 This is a schematic diagram of the structure of the automatic frequency and equivalent impact device in this invention;

[0038] Figure 4 This is a cross-sectional view of the spindle-shaped punch and its supporting device in this invention;

[0039] Figure 5 This is a left view of the spindle-shaped punch and its supporting device in this invention;

[0040] Figure 6 This is a schematic diagram of the slide rail and guide rail in this invention;

[0041] Figure 7 This is a cross-sectional view of the slide rail and guide rail assembly in this invention;

[0042] Figure 8 This is a front view of the slide rail and guide rail assembly in this invention.

[0043] In the diagram, 1 represents the intelligent servo control drive system;

[0044] 2. First support;

[0045] 3. Guide rail;

[0046] 4. Spindle-shaped punch;

[0047] 5. Slide rail;

[0048] 6. Punch carrying device;

[0049] 7. Infrared emitting probe;

[0050] 8. Steel impact pads;

[0051] 9. Incident rod;

[0052] 10. Second support;

[0053] 11. Strain gauge;

[0054] 12. Multi-field coupling experimental setup;

[0055] 13. Transmission rod;

[0056] 14. Absorption rod;

[0057] 15. Axial compression loading cavity;

[0058] 16. System base;

[0059] 17. Infrared timer;

[0060] 18. Temperature-controlled compressor;

[0061] 19. Temperature control fluid inlet pipeline;

[0062] 20. Temperature control fluid output pipeline;

[0063] 21. Digital temperature sensor;

[0064] 22. Ultra-dynamic strain gauge;

[0065] 23. Oscilloscope recorder;

[0066] 24. Data processor;

[0067] 25. Digital display axial pressure loading pump;

[0068] 26. Digital display confining pressure loading pump;

[0069] 27. Adapter valve;

[0070] 28. Exhaust gas treatment device;

[0071] 29. Vacuum pump;

[0072] 30. High-frequency barometer;

[0073] 31. High-frequency gas flow meter;

[0074] 32. High-pressure methane cylinder;

[0075] 33. Control valve for confining pressure loading pipeline;

[0076] 34. Exhaust gas treatment pipeline control valve;

[0077] 35. Gas injection pipeline control valve;

[0078] 36. Axial pressure loading pipeline control valve;

[0079] 37. Temperature control fluid output pipeline control valve;

[0080] 38. Vacuum pump pipeline control valve;

[0081] 39. Heat shrink tubing;

[0082] 40. Confining pressure loading pipeline interface;

[0083] 41. Gas injection pipeline interface;

[0084] 42. Snap-fit ​​sealing adapter;

[0085] 43. Sample;

[0086] 44. Temperature control fluid inlet pipe interface;

[0087] 45. Temperature control fluid output pipeline interface;

[0088] 46. ​​Temperature control fluid pipeline;

[0089] 47. Punch carrying device hinge support;

[0090] 48. Intelligent servo drive system piping;

[0091] 49. Embedded high-elastic rubber gasket;

[0092] 50. Card slot;

[0093] 51. Fixing bolt holes. Detailed Implementation

[0094] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0095] Reference Figures 1 to 8 This is the first embodiment of the present invention, which provides a dynamic experimental system and method for gas-bearing coal with controllable impact frequency and equivalent. The system includes an intelligent servo control drive device, a guide rail 3, a slide rail 5, a punch carrying device 6, a spindle-shaped punch 4, a steel impact pad 8, an incident rod 9, a transmission rod 13, an absorption rod 14, and a multi-field coupling experimental device 12. The intelligent servo control drive device intelligently controls the slide rail 5 mounted on the guide rail 3 through program assignment, thereby driving the punch carrying device 6 and the internal spindle-shaped punch 4 to reciprocate, achieving impacts with different impact frequencies and equivalents. The steel impact pad 8, the incident rod 9, the transmission rod 13 and the absorption rod 14 are collinear. A multi-field coupling experimental device 12 is set between the incident rod 9 and the transmission rod 13. The multi-field coupling experimental device 12 is equipped with a gas injection pipeline interface 41, a confining pressure loading pipeline interface 40, a temperature control liquid input pipeline interface 19 and a temperature control liquid output pipeline interface 20. Strain gauges 11 are attached to the incident rod 9 and the transmission rod 13 respectively. The strain gauges 11 are connected to the ultra-dynamic strain gauge 22 through twisted pair cables and are connected to the oscilloscope recorder 23 and the data processor 24.

[0096] Specifically, the two guide rails 3 are parallel to each other, and the guide rails 3 on the same side are connected by bolts and steel bars of the same length. The guide rails 3 are embedded in the slide rails 5 to ensure that the slide rails 5 always slide along the prescribed route.

[0097] Furthermore, this connection structure can effectively limit the movement trajectory of the slide rail 5, ensuring that the slide rail 5 always slides along the prescribed route, thereby ensuring the accuracy of the impact position of the spindle-shaped punch 4.

[0098] Specifically, the slide rail 5 and the punch carrying device 6 are connected by a bolt-hinged support, and also include a locking groove 50. The locking groove 50 is used to calibrate the position of the slide rail 5 to correct the equivalent error caused by long-term high-frequency impact.

[0099] Furthermore, this connection not only ensures a stable fixation between the two but also allows for minor angular adjustments to the punch-carrying device 6 to a certain extent, which helps to buffer the stress generated during the impact. At the same time, in long-term high-frequency impact experiments, the slide rail 5 may experience a slight positional shift due to the accumulated impact force, which may lead to errors in the impact equivalent. Regularly calibrating and correcting the position of the slide rail 5 through the locking groove 50 can effectively reduce this error and ensure the reliability of the experimental data.

[0100] Specifically, the punch carrying device 6 has an embedded high-elastic rubber pad 49, which is used to ensure that the spindle-shaped punch 4 is stable during the launch process and collides with the steel impact pad 8.

[0101] Furthermore, the embedded high-elastic rubber pad 49 can absorb some of the impact energy, reduce vibration during the impact process, ensure the stability of the spindle-shaped punch 4 during the launch process, and at the same time, the position of the spindle-shaped punch 4 can be finely adjusted to ensure that it collides head-on with the steel impact pad 8, thereby improving the accuracy of the experiment.

[0102] Specifically, a snap-fit ​​sealing adapter 42 is connected to the gas injection pipeline interface 41 and is connected to the heat shrink tubing 39. The sample 43 is installed in the heat shrink tubing 39 between the injection rod 9 and the transmission rod 13.

[0103] Furthermore, the prepared gas-containing coal sample 43 is installed in the heat shrink tube 39 between the incident rod 9 and the transmission rod 13. The heat shrink tube 39 can effectively wrap and fix the sample 43, while the snap-on sealing adapter 42 can ensure the sealing during the gas injection process and prevent gas leakage from affecting the experimental results.

[0104] Specifically, the gas injection pipeline interface 41 is connected to the adapter valve 27 via an external pipeline. The adapter valve 27 is connected to the vacuum pump 29 pipeline control valve and then to the vacuum pump 29. It is also connected to the tail gas treatment pipeline control valve 34 and to the tail gas treatment device 28. Furthermore, it is connected to the high-frequency gas pressure gauge 30 and the high-frequency gas flow meter 31, and is connected to the methane high-pressure cylinder 32 via the gas injection pipeline control valve 35.

[0105] Furthermore, the adapter valve 27 is connected to the vacuum pump 29 via a branch control valve. Before the experiment, the entire gas pipeline and the area around the sample 43 can be evacuated by the vacuum pump 29 to remove interference from air and other impurities. The tail gas treatment pipeline control valve 34 is connected to the tail gas treatment device 28. The tail gas generated during the experiment can enter the tail gas treatment device 28 through this pipeline for purification to avoid environmental pollution. The high-frequency gas pressure gauge 30 can collect and store the change data of gas pressure at the moment of impact in real time, providing a basis for calculating the work done by gas expansion. The high-frequency gas flow meter 31 can collect and store the change of gas flow at the moment of impact for calculating the gas permeability. This pipeline is connected to the methane high-pressure cylinder 32 through the gas injection pipeline control valve 35, which can adjust the injection volume and pressure of methane according to experimental requirements.

[0106] Specifically, the confining pressure loading pipeline interface 40 is connected to the digital display confining pressure loading pump 26 via the external confining pressure loading pipeline control valve 33.

[0107] Furthermore, the digital display confining pressure loading pump 26 can precisely control the magnitude of the confining pressure and apply confining pressure to the multi-field coupling experimental device 12 through the confining pressure loading pipeline to simulate the confining pressure environment experienced by gas-bearing coal at different underground depths.

[0108] Specifically, it also includes a temperature-controlled compressor 18. When the temperature-controlled compressor 18 is working, it opens the control valve of the temperature-controlled liquid output pipeline 20. The temperature-controlled liquid input pipeline 19 is connected to the interface of the temperature-controlled liquid input pipeline 19 in the multi-field coupling experimental device 12. The liquid flows through the temperature-controlled liquid pipeline 46 to the interface of the temperature-controlled liquid output pipeline 20 in the multi-field coupling experimental device 12 to achieve heat transfer temperature control. It also includes a temperature digital display sensor 21, which is used to record the liquid temperature in real time and stabilize the liquid temperature to the set temperature.

[0109] Furthermore, when the temperature control compressor 18 is working, the control valve of the temperature control liquid output pipeline 20 needs to be opened. The temperature control liquid input pipeline 19 is connected to the interface of the temperature control liquid input pipeline 19 in the multi-field coupling experimental device 12. The temperature control liquid flows through the temperature control liquid pipeline 46 to the interface of the temperature control liquid output pipeline 20 in the multi-field coupling experimental device 12, forming a circulation loop to achieve heat transfer and control the temperature of the experimental environment. At the same time, the temperature digital display sensor 21 records the liquid temperature in real time. The staff can adjust the temperature according to the digital display data to ensure that the liquid temperature is stable to the experimental set temperature, providing a stable temperature environment for the experiment.

[0110] Specifically, it also includes a digital display axial pressure loading pump 25, which is connected to the axial pressure loading pipeline control valve 36 via a pipeline and connected to the axial pressure loading chamber 15 for applying axial static load.

[0111] Furthermore, in terms of data acquisition during the impact process, strain gauges 11 are attached to the incident rod 9 and the transmission rod 13, respectively. The strain gauges 11 are connected to the ultra-dynamic strain gauge 22 via twisted-pair cables. The ultra-dynamic strain gauge 22 can accurately capture the tiny strain signals generated at the moment of impact and transmit these signals to the oscilloscope recorder 23 and the data processor 24. The oscilloscope recorder 23 can display the change curve of the strain signal in real time, while the data processor 24 analyzes and processes these signals to obtain the dynamic parameters of gas-bearing coal under different impact conditions.

[0112] A dynamic experimental method for gas-bearing coal with controllable impact frequency and equivalent includes the following steps:

[0113] S1. Apply Vaseline to both ends of the sample 43 and place it in the heat shrink tubing 39. Align the two ends of the sample 43 with the axes of the incident rod 9 and the transmission rod 13, respectively, so that the sample 43 is in a sealed state to keep it isolated from the hydraulic oil in the multi-field coupling experimental device 12.

[0114] S2. Open the axial pressure loading pipeline control valve 36 and slowly press hydraulic oil into the axial pressure loading chamber 15 through the digital display axial pressure loading pump 25 to apply axial pressure to the sample 43 in the multi-field coupling experimental device 12. When the preset axial load of the test is reached, close the axial pressure loading pipeline control valve 36.

[0115] S3. Close all control valves of the external device of the multi-field coupling experimental device 12, and only open the control valve of the vacuum pump 29 pipeline to start the vacuum pump 29 to evacuate the vacuum until the high-frequency acquisition pressure gauge 30 stabilizes to a constant negative pressure, and then close the control valve of the vacuum pump 29 pipeline.

[0116] S4. Open the confining pressure loading pipeline control valve 33 and slowly pressurize hydraulic oil into the multi-field coupling experimental device 12 through the digital display axial pressure loading pump 25; when the pre-set confining pressure is reached, close the confining pressure loading pipeline control valve 33.

[0117] S5. Open the high-pressure methane cylinder 32 and the gas injection pipeline control valve 35. At this time, the gas from the high-pressure methane cylinder 32 will be injected along the pipeline between the injection rod 9 and the transmission rod 13 and onto the sample 43 inside the heat shrink tube 39. When the preset gas pressure value is reached, immediately close the gas injection pipeline control valve 35. Then the coal body enters the gas adsorption step.

[0118] S6. Open the control valve of the temperature control liquid output line 20, turn on the temperature control compressor 18 and set the liquid output temperature. Heat transfer is carried out through the temperature control liquid line 46. The temperature digital display sensor 21 records the liquid temperature change in real time. When the output temperature is consistent with the set temperature and the gas pressure of the high-frequency gas pressure gauge 30 is stable, close the control valve of the temperature control liquid output line 20 and enter the preparation stage before the impact test.

[0119] S7. Turn on the ultra-dynamic strain gauge 22, oscilloscope recorder 23, data processor 24 and infrared timer 17. Also, set the timer to store data according to the acquisition frequency.

[0120] S8. After setting the impact frequency and impact equivalent, turn on the intelligent servo control drive device and start the transmission switch of the intelligent servo control drive device to carry out the impact test of gas-containing coal. At this time, the stress wave is transmitted to the coal and rock sample 43 through the incident rod 9, then to the transmission rod 13 through the sample 43, and finally to the absorption rod 14.

[0121] S9. After the impact test of each sample 43 is completed, open the tail gas treatment pipeline control valve 34 to carry out gas tail gas treatment.

[0122] S10. Process the data collected during the impact process, including stress wave curves, gas pressure and flow rate changes, and analyze the mechanical response characteristics of gas-bearing coal, the work done by gas expansion, and permeability characteristics.

[0123] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

Claims

1. A dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent includes, characterized in that: The device includes an intelligent servo control drive unit, a guide rail, a slide rail, a punch carrying device, a spindle-shaped punch, a steel impact pad, an incident rod, a transmission rod, an absorption rod, and a multi-field coupling experimental device. The intelligent servo control drive unit intelligently controls the slide rail mounted on the guide rail through program assignment to drive the punch carrying device and the internal spindle-shaped punch to reciprocate, achieving impacts on the steel impact pad with different impact frequencies and equivalent quantities. The central axes of the steel impact pad, the incident rod, the transmission rod, and the absorption rod are collinear. A multi-field coupling experimental device is set between the incident rod and the transmission rod. The multi-field coupling experimental device is equipped with a gas injection pipeline interface, a confining pressure loading pipeline interface, a temperature control liquid input pipeline interface, and a temperature control liquid output pipeline interface. Strain gauges are attached to the incident rod and the transmission rod, respectively. The strain gauges are connected to an ultra-dynamic strain gauge via twisted-pair cables and are connected to an oscilloscope recorder and a data processor.

2. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: The guide rails on both sides are parallel to each other, and the guide rails on the same side are connected by bolts and steel bars of the same length. The guide rails are embedded in the slide rail to ensure that the slide rail always slides along the prescribed route.

3. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: The slide rail and the punch carrying device are connected by a bolt-hinged support, and also include a positioning groove. The positioning groove is used to calibrate the position of the slide rail to correct the equivalent error caused by long-term high-frequency impact.

4. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: The punch carrying device has an embedded high-elastic rubber pad to ensure that the spindle-shaped punch is stable during launch and collides concentrically with the steel impact pad.

5. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: The gas injection pipeline interface is internally connected to a snap-fit ​​sealing adapter and connected to a heat shrink tubing. The sample is installed in the heat shrink tubing, between the incident rod and the transmission rod.

6. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: The gas injection pipeline interface is connected to the adapter valve via an external pipeline. The adapter valve is connected to the vacuum pump pipeline control valve and then to the vacuum pump. It is also connected to the tail gas treatment pipeline control valve and then to the tail gas treatment device. Additionally, it is connected to the high-frequency gas pressure gauge and the high-frequency gas flow meter, and finally to the methane high-pressure cylinder via the gas injection pipeline control valve.

7. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: The confining pressure loading pipeline interface is connected to the digital display confining pressure loading pump via an external confining pressure loading pipeline control valve.

8. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: It also includes a temperature-controlled compressor. When the temperature-controlled compressor is working, it opens the control valve of the temperature-controlled liquid output pipeline. The temperature-controlled liquid input pipeline is connected to the temperature-controlled liquid input pipeline interface in the multi-field coupling experimental device. The liquid flows through the temperature-controlled liquid pipeline to the temperature-controlled liquid output pipeline interface in the multi-field coupling experimental device to achieve heat transfer temperature control. It also includes a temperature digital display sensor for real-time recording of liquid temperature, and the liquid temperature is stabilized to the set temperature.

9. The dynamic experimental system for gas-bearing coal with controllable impact frequency and equivalent as described in claim 1, characterized in that: It also includes a digital display axial pressure loading pump, which is connected to the axial pressure loading pipeline control valve via a pipeline and connected to the axial pressure loading chamber for applying axial static load.

10. A dynamic experimental method for gas-bearing coal with controllable impact frequency and equivalent according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Apply Vaseline to both ends of the sample and place them in heat shrink tubing. Align the two ends of the sample with the axes of the incident rod and the transmission rod, respectively, to keep the sample sealed and isolated from the hydraulic oil in the multi-field coupling experimental device. S2. Open the axial pressure loading pipeline control valve and slowly pressurize hydraulic oil into the axial pressure loading chamber through the digital display axial pressure loading pump to apply axial pressure to the sample in the multi-field coupling experimental device. When the preset axial load of the test is reached, close the axial pressure loading pipeline control valve. S3. Close all control valves of the external devices of the multi-field coupling experimental setup, and only open the vacuum pump pipeline control valve to start the vacuum pump for evacuation until the high-frequency pressure gauge stabilizes at a constant negative pressure, then close the vacuum pump pipeline control valve. S4. Open the confining pressure loading pipeline control valve and slowly pressurize hydraulic oil into the multi-field coupling experimental device through the digital display axial pressure loading pump; when the pre-set confining pressure is reached, close the confining pressure loading pipeline control valve. S5. Open the high-pressure methane cylinder and the gas injection pipeline control valve. At this time, the gas from the high-pressure methane cylinder will be injected along the pipeline between the injection rod and the transmission rod, and onto the sample inside the heat shrink tube. When the preset gas pressure value is reached, immediately close the gas injection pipeline control valve, and then the coal body enters the gas adsorption step. S6. Open the control valve of the temperature control liquid output pipeline, turn on the temperature control compressor and set the liquid output temperature. Heat transfer is carried out through the temperature control liquid pipeline. The temperature digital display sensor records the liquid temperature change in real time. When the output temperature is consistent with the set temperature and the gas pressure of the high-frequency gas pressure gauge is stable, close the control valve of the temperature control liquid output pipeline and enter the preparation stage before the impact test. S7. Turn on the ultra-dynamic strain gauge, oscilloscope recorder, data processor and infrared timer. Also, set the timer to store data according to the acquisition frequency. S8. After setting the impact frequency and impact equivalent, turn on the intelligent servo control drive device and start the transmission switch of the intelligent servo control drive device to conduct the impact test of gas-containing coal. At this time, the stress wave is transmitted to the coal and rock sample through the incident rod, then to the transmission rod through the sample, and finally to the absorption rod. S9. After the impact test of each sample is completed, open the control valve of the exhaust gas treatment pipeline to perform gas exhaust gas treatment. S10. Process the data collected during the impact process, including stress wave curves, gas pressure and flow rate changes, and analyze the mechanical response characteristics of gas-bearing coal, the work done by gas expansion, and permeability characteristics.

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