A dynamic load disturbance test system with stress-gas-temperature multi-field coupling

Abstract

The present invention discloses a stress-gas-temperature multi-field coupled dynamic load disturbance test system, which belongs to the field of safety science and engineering. The system comprises a test bench, the upper surface of which is provided with a test cavity, the interior of which is provided with a true triaxial confining pressure zone loading system and a formation zone heating system, a first gas pipeline extending through the bottom corner of the right wall of the test cavity, the interior of the test cavity being connected to an adsorption gas pressurization system via the first gas pipeline, a collision pressure plate extending through the left inner wall of the test cavity, and an external dynamic load disturbance system being provided on the left side of the collision pressure plate. The present invention adopts the above-mentioned stress-gas-temperature multi-field coupled dynamic load disturbance test system to study the effects of dynamic load, confining pressure, air pressure, and geothermal heat on the mechanical properties of the specimen, as well as its effects on damage, crack development, and gas adsorption and desorption, thereby providing guidance for safe production in coal mines.

Description

Technical Field

[0001] The present invention relates to the field of safety science and engineering, and in particular to a stress-gas-temperature multi-field coupled dynamic load disturbance test system. Background Art

[0002] Currently, my country's shallow coal resources have been largely mined, with mining now primarily focused on central and a few deep coal resources, with mining occurring at a rate of 10-20 m / year. As my country's annual coal demand increases, deeper coal resources will inevitably become the primary target for mining. As coal seam mining deepens, the seam's host environment becomes increasingly complex, characterized by increased ground stress, gas pressure, gas content, decreased coal seam permeability, and elevated ground temperatures. This makes it more likely to trigger accidents such as rock bursts and coal and gas outbursts, increasing the severity of coal mine accidents and presenting significant challenges to the mining process.

[0003] Coal mine accidents are caused by the coupling of multiple factors, and their mechanisms are complex and diverse. An example is coal and gas outbursts. Therefore, to explore the mechanisms of coal and gas outburst accidents, it is necessary to simulate and study the mechanical properties, damage, fracture development, gas adsorption and desorption, and other related aspects of raw coal rock specimens under realistic geological environments. This can effectively prevent the risk of accidents, reduce the number of accidents, and mitigate their severity, providing valuable guidance for addressing the safety of deep coal mining and underground engineering excavation. A literature review revealed that most existing testing systems incorporate true triaxial testing equipment and related research. True triaxial testing equipment is designed so that each true triaxial loading platen represents a loading zone, and the pressure within the loading zone is assumed to be uniform everywhere, enabling true triaxial surface stress loading in different directions. However, existing testing systems suffer from functional limitations, such as the inability to implement zoned platen stress loading, failure to account for geothermal factors, and lack of external dynamic load perturbation capabilities. Consequently, they cannot fully reproduce the true geological environment in which coal and rock strata occur, and thus fail to fully reveal the mechanisms of coal and gas outburst accidents.

[0004] To address the inadequacies of existing testing systems, a dynamic load perturbation test system with a stress-gas-temperature multi-field coupling is needed. This test system, based on the existing system, adds an external dynamic load perturbation device and a formation heating device, while also improving the true triaxial confining pressure loading device. This not only meets the requirements for external impact dynamic load perturbation, but also adds formation geothermal and zoned heating capabilities, achieving true triaxial confining pressure and zoned loading. This test system can be used to study the effects of external dynamic loads of varying intensities on the mechanical properties of coal and rock samples, the effects of true triaxial confining pressure and zoned loading on the mechanical properties of coal and rock samples, and the effects of zoned formation heating on the mechanical properties of coal and rock samples. Researching a dynamic load perturbation test system with a stress-gas-temperature multi-field coupling will not only help prevent coal and gas outburst accidents, but also guide coal mine safety production. Summary of the Invention

[0005] The purpose of the present invention is to provide a stress-gas-temperature multi-field coupled dynamic load disturbance test system, which can not only be used to study the changes in the mechanical properties of samples caused by dynamic load disturbances of different intensities, the changes in the mechanical properties of samples caused by different confining pressure zone loading, the changes in the mechanical properties of samples caused by different air pressure environments, and the changes in the mechanical properties of samples caused by different geothermal environments, but can also further study the effects of changes in the mechanical properties of samples on their damage, crack development, and gas adsorption and desorption, providing favorable guidance for safe production in coal mines.

[0006] To achieve the above-mentioned objectives, the present invention provides a stress-gas-temperature multi-field coupled dynamic load disturbance test system, comprising a test bench, a test cavity provided on the upper surface of the test bench, a true triaxial confining pressure partitioned loading system and a formation partitioned heating system provided inside the test cavity, a first gas pipeline passing through the bottom corner of the right side wall of the test cavity, an adsorption gas pressurization system connected to the inside of the test cavity through the first gas pipeline, a collision pressure plate passing through the left inner wall of the test cavity, and an external dynamic load disturbance system provided on the left side of the collision pressure plate.

[0007] Preferably, one side of the test cavity is connected to an anti-collision bracket via a fixing bolt, and the anti-collision bracket is fixed to the upper surface of the experimental table.

[0008] Preferably, the true triaxial confining pressure zoned loading system includes several hydraulic oil pumps, pressure plates, and air pressure sensors. Several of the hydraulic oil pumps are arranged through the outer surface of the test cavity. The pressure plates are arranged on the inner wall surface of the test cavity and connected to the output ends of several of the hydraulic oil pumps. The air pressure sensors are arranged at the top corners of the test cavity.

[0009] Preferably, the pressure plate is composed of several small pressure plates, each of which is connected to the output end of the hydraulic oil pump. The formation zone heating system includes the small pressure plate, a heating wire, a thermocouple, and a temperature control box. A groove is provided on the surface of the small pressure plate away from the hydraulic oil pump. The heating wire and the thermocouple are arranged inside the groove on the surface of the small pressure plate. The heating wire and the thermocouple are respectively connected to the temperature control box with wires.

[0010] Preferably, the adsorption gas pressurization system includes an adsorption gas cylinder, a first pressure regulating valve, a first pressure gauge, and a first switch. The adsorption gas cylinder is connected to the first gas pipeline through the first pressure regulating valve, the first pressure gauge, and the first switch in sequence, and the air pressure entering the test chamber is adjusted by controlling the first pressure regulating valve and the first switch.

[0011] Preferably, the external dynamic load disturbance system includes a nitrogen cylinder, a second gas pipeline, a gas storage cylinder, a slider, a light speed sensor, an acceleration pipeline, a data acquisition instrument, and a bracket. The nitrogen cylinder is connected to the gas storage cylinder through the second gas pipeline. The second gas pipeline is connected to a second pressure regulating valve, a second pressure gauge, and a second switch. The internal air pressure of the gas storage cylinder is adjusted by controlling the second pressure regulating valve and the second switch. The second pressure indication number is the internal air pressure value of the gas storage cylinder.

[0012] Preferably, the gas cylinder is connected to one end of the acceleration pipe through a third gas pipe, and a solenoid valve is provided at the connection between the third gas pipe and the gas cylinder. The other end of the acceleration pipe corresponds to the outer end surface of the collision pressure plate, and the slider is arranged inside the acceleration pipe. The gas cylinder and the acceleration pipe are both fixed to the upper surface of the experimental table through the bracket, and the light speed sensor is arranged on the inner wall of the acceleration pipe near one end of the collision pressure plate.

[0013] Therefore, the present invention adopts the above-mentioned stress-gas-temperature multi-field coupled dynamic load disturbance test system, which has the following technical effects:

[0014] (1) The present invention includes an external dynamic load disturbance system, which can realize dynamic load disturbances of different intensities, simulate and study the changes in the mechanical properties of coal and rock samples caused by dynamic load disturbances of different intensities, provide a strong basis for the study of damage and destruction of coal and rock samples, and have important significance for the study of coal and rock stratum failure morphology;

[0015] (2) The present invention includes a true triaxial confining pressure zone loading system, which can realize confining pressure zone loading of coal rock samples, simulate and study the changes in the mechanical properties of coal rock samples caused by different confining pressure zone loading, provide parameter support for the study of crack development in coal rock samples, and is of great significance for the study of improving coal seam permeability;

[0016] (3) The present invention includes an adsorbed gas pressurization system, which can realize the gas pressure environment in which the coal rock sample is located, simulate and study the changes in the mechanical properties of the coal rock sample under different gas pressure environments, play a guiding role in the prevention and control of accidents such as coal and gas outbursts, and is of great significance to ensuring safe production in coal mines;

[0017] (4) The present invention includes a formation zone heating system, which can realize zone heating of coal rock samples, simulate and study the changes in the mechanical properties of coal rock samples under different geothermal environments, provide a strong basis for the study of damage and fracture development of coal rock samples, and is of great significance to coal mine safety production and accident prevention.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a stress-gas-temperature multi-field coupled dynamic load disturbance test system of the present invention;

[0020] Figure 2 This is a schematic diagram of the pressure plate structure of a stress-gas-temperature multi-field coupled dynamic load disturbance test system of the present invention;

[0021] Figure 3 The present invention is a schematic diagram of heating a small pressing plate in a stress-gas-temperature multi-field coupled dynamic load disturbance test system.

[0022] Reference numerals

[0023] 1. Experimental table; 2. Test chamber; 3. True triaxial confining pressure zone loading system; 31. Hydraulic oil pump; 32. Pressure plate; 321. Small pressure plate; 33. Air pressure sensor; 4. Formation zone heating system; 41. Heating wire; 42. Thermocouple; 43. Temperature control box; 5. First gas pipeline; 6. Adsorption gas pressurization system; 61. Adsorption gas cylinder; 62. First pressure regulating valve; 63. First pressure gauge; 64. First switch; 7. Collision pressure plate; 8. External dynamic load disturbance system; 81. Nitrogen cylinder; 82. Second gas pipeline; 83. Gas storage cylinder; 84. Slider; 85. Light speed sensor; 86. Acceleration pipeline; 87. Bracket; 9. Anti-collision bracket; 10. Solenoid valve; 11. Third gas pipeline; 12. Second pressure regulating valve; 13. Second pressure gauge; 14. Second switch; 15. Data acquisition instrument. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0025] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0026] Example 1

[0027] like Figures 1 to 2 As shown, a stress-gas-temperature multi-field coupled dynamic load disturbance test system includes a test bench 1, the upper surface of which is provided with a test cavity 2. One side of the test cavity 2 is connected to an anti-collision bracket 9 by a fixing bolt. The anti-collision bracket 9 is fixed to the upper surface of the test bench 1 to ensure the stability and safety of the test cavity 2. The test cavity 2 is made of an alloy material with a high stiffness coefficient and is connected with high-strength bolts to prevent deformation and damage to the structure of the test cavity 2 during the test. The inside of the test cavity 2 is provided with a true triaxial confining pressure zone loading system 3 and a formation zone heating system 4.

[0028] The true triaxial confining pressure zone loading system 3 includes a number of hydraulic oil pumps 31, pressure plates 32, and air pressure sensors 33. The hydraulic oil pump 31 is arranged on the outer surface of the test cavity 2, and the pressure plate 32 is arranged on the inner wall surface of the test cavity 2 and is connected to the output ends of the hydraulic oil pumps 31, and is used to perform confining pressure loading on the test piece inside the test cavity 2. The air pressure sensor 33 is arranged at the top corner of the test cavity 2 and is used to monitor the air pressure changes inside the test cavity 2. Among them, the pressure plate 32 is spliced ​​together by a number of small pressure plates 321, and each small pressure plate 321 is connected to the output end of the hydraulic oil pump 31. In this way, the loading pressure of different areas can be controlled more accurately, and both graded confining pressure loading and synchronous confining pressure loading can be achieved.

[0029] like Figure 3 As shown, the formation zone heating system 4 includes a small pressing plate 321, a heating wire 41, a thermocouple 42, and a temperature control box 43. A groove is provided on the side of the small pressing plate 321 facing away from the hydraulic oil pump 31. The heating wire 41 and thermocouple 42 are located within the groove on the surface of the small pressing plate 321 to provide localized heating and temperature monitoring for the specimen. The heating wire 41 and thermocouple 42 are connected to the temperature control box 43 via wires to achieve precise temperature control.

[0030] A first gas pipeline 5 runs through the bottom corner of the side wall of the test chamber 2, near the anti-collision bracket 9. This first gas pipeline 5 connects the interior of the test chamber 2 to an adsorption gas pressurization system 6. This system comprises an adsorption gas cylinder 61, a first pressure-regulating valve 62, a first pressure gauge 63, and a first switch 64. The adsorption gas cylinder 61 is connected to the first gas pipeline 5 via the first pressure-regulating valve 62, the first pressure gauge 63, and the first switch 64. The air pressure entering the test chamber 2 is adjusted by controlling the first pressure-regulating valve 62 and the first switch 64.

[0031] A collision plate 7 is provided through the left inner wall of the test chamber 2, and an external dynamic load perturbation system 8 is provided on the left side of the collision plate 7. The external dynamic load perturbation system 8 comprises a nitrogen cylinder 81, a second gas pipeline 82, a gas cylinder 83, a slider 84, a light velocity sensor 85, an acceleration pipeline 86, a bracket 87, and a data acquisition device 15. The nitrogen cylinder 81 is connected to the gas cylinder 83 via the second gas pipeline 82. The second gas pipeline 82 is connected to a second pressure regulating valve 12, a second pressure gauge 13, and a second switch 14. The internal pressure of the gas cylinder 83 is regulated by controlling the second pressure regulating valve 12 and the second switch 14. The reading on the second pressure gauge 13 is the internal pressure value of the gas cylinder 83. The gas cylinder 83 is connected to one end of the acceleration pipeline 86 via a third gas pipeline 11. A solenoid valve 10 is provided at the connection between the third gas pipeline 11 and the gas cylinder 83. The solenoid valve 10 is manually operated to control the release of gas from the gas cylinder 83, and there is no gas leakage at the outlet. The other end of the acceleration pipe 86 corresponds to the outer end surface of the collision plate 7. The slider 84 is arranged inside the acceleration pipe 86. The acceleration pipe 86 is a rigid and smooth pipe. Under the action of nitrogen, the slider 84 performs approximately frictionless motion along the inner wall of the pipe. The slider 84 hits the outer end of the collision plate 7, thereby applying dynamic load disturbance to the specimen inside the test cavity 2. The gas cylinder 83 and the acceleration pipe 86 are both fixed to the upper surface of the experimental table 1 by the bracket 87. The light speed sensor 85 is arranged on the inner wall of the acceleration pipe 86 near one end of the collision plate 7 and is connected to the data acquisition instrument 15 for monitoring the moving speed of the slider 84. The air pressure sensor 33 in the true triaxial confining pressure zone loading system 3 is also electrically connected to the data acquisition instrument 15 for monitoring the air pressure changes inside the test cavity 2.

[0032] Working principle: 1. Activate the true triaxial confining pressure zone loading system 3, place the specimen into the test chamber 2, control the computer and set the same but smaller loading value for the hydraulic oil pump 31, and pressurize the specimen with the pressure plate 32;

[0033] 2. Activate the adsorbed gas pressurization system 6: After the pressure plate 32 has completed pressurizing and fixing the sample, adjust the first pressure regulating valve 62. After the reading of the first pressure gauge 63 reaches a preset value and stabilizes, open the first switch 64 to force the adsorbed gas into the chamber, and close the first switch 64 in time.

[0034] 3. Activate the formation zone heating system 4: After the adsorption gas is pressurized, turn on the temperature control box 43 and adjust the heat output of the heating wire 41 by the knob to control the formation zone heating temperature;

[0035] 4. Activate the true triaxial confining pressure zone loading system 3: After the heating temperature of the pressure plate 32 reaches the preset value and stabilizes, the hydraulic oil pump 31 adjusts the small pressure plate 321 to achieve zoned pressurization and heating of the specimen;

[0036] 5. Activate the external dynamic load disturbance system 8: After the sample is pressurized and heated in each zone, adjust the second pressure regulating valve 12. After the reading of the second pressure gauge 13 reaches a preset value and stabilizes, open the second switch 14 to allow nitrogen to enter the gas cylinder 83. Close the second switch 14 promptly, and then open the solenoid valve 10 to release the nitrogen in the gas cylinder 83.

[0037] 6. Enable the data acquisition system: connect the data acquisition instrument 15 to the sensor, output and display and record the relevant monitoring data.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A stress-gas-temperature multi-field coupled dynamic load disturbance test system, characterized by: The test bench comprises a test chamber provided on the upper surface thereof, a true triaxial confining pressure zoned loading system and a formation zoned heating system provided inside the test chamber, a first gas pipeline penetrating the bottom corner of the right side wall of the test chamber, an adsorption gas pressurization system connected to the inside of the test chamber via the first gas pipeline, a collision pressure plate penetrating the left inner wall of the test chamber, and an external dynamic load disturbance system provided on the left side of the collision pressure plate; The true triaxial confining pressure partition loading system includes several hydraulic oil pumps, pressure plates, and air pressure sensors. Several of the hydraulic oil pumps are arranged on the outer surface of the test cavity. The pressure plate is arranged on the inner wall surface of the test cavity and is connected to the output ends of several of the hydraulic oil pumps. The air pressure sensor is arranged at the top corner of the test cavity. The pressure plate is composed of several small pressure plates, and each of the small pressure plates is connected to the output end of the hydraulic oil pump. The formation partition heating system includes the small pressure plate, a heating wire, a thermocouple, and a temperature control box. A groove is provided on the surface of the small pressure plate away from the hydraulic oil pump. The heating wire and the thermocouple are arranged inside the groove on the surface of the small pressure plate. The heating wire and the thermocouple are respectively connected to the temperature control box with wires; The adsorption gas pressurization system includes an adsorption gas cylinder, a first pressure regulating valve, a first pressure gauge, and a first switch. The adsorption gas cylinder is connected to the first gas pipeline through the first pressure regulating valve, the first pressure gauge, and the first switch in sequence. The pressure of the gas entering the test chamber is adjusted by controlling the first pressure regulating valve and the first switch. The external dynamic load disturbance system includes a nitrogen cylinder, a second gas pipeline, a gas cylinder, a slider, a light speed sensor, an acceleration pipeline, and a bracket. The nitrogen cylinder is connected to the gas cylinder through the second gas pipeline. The second gas pipeline is connected to a second pressure regulating valve, a second pressure gauge, and a second switch. The internal pressure of the gas cylinder is adjusted by controlling the second pressure regulating valve and the second switch. The second pressure display number is the internal pressure value of the gas cylinder. The gas cylinder is connected to one end of the acceleration pipe through a third gas pipe. A solenoid valve is provided at the connection between the third gas pipe and the gas cylinder. The other end of the acceleration pipe corresponds to the outer end surface of the collision pressure plate. The slider is arranged inside the acceleration pipe. The gas cylinder and the acceleration pipe are both fixed to the upper surface of the experimental table through the bracket. The light speed sensor is arranged on the inner wall of the acceleration pipe near one end of the collision pressure plate.

2. The stress-gas-temperature multi-field coupled dynamic load disturbance test system according to claim 1, characterized in that: One side of the test cavity is connected to the anti-collision bracket through a fixing bolt, and the anti-collision bracket is fixed to the upper surface of the experimental table.

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