Test device and method for coal and gas outburst induced by structure-stress-gas coupling

Abstract

The invention discloses a structure-stress-gas coupling induced coal and gas outburst test device and method, which can control a hydraulic loading device to carry out stress destruction on a coal rock layer in a box body according to test requirements, simulate formation processes of different structures such as faults, wrinkles and the like in situ, a structure stress evolution process and in-situ stress distribution characteristics in situ, and improve the test accuracy. Then the remaining space of the box body is filled with the expansion air bag, the box body is inflated by controlling the position of the air injection hole, the air injection rate and the adsorption time, the occurrence form of the gas in the coal rock layer and the heterogeneous distribution characteristics of the gas in different geological environments are simulated, and finally explosives laid in the coal rock layer are detonated. Dynamic load disturbance destroys a coal rock stratum and sealed raw coal at an outburst port actively induces outburst, so that critical stress, stress distribution characteristics, critical gas pressure and gas pressure change characteristics when outburst occurs to geological structures such as faults and wrinkles can be determined.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to a test device and method for tectonic-stress-gas coupling induced coal and gas outburst. Background Art

[0002] The main characteristics of my country's geotectonic system include that it is composed of complex small land blocks through multiple cyclic tectonic movements and is located at the junction of active plates, which are mainly characterized by poor stability and strong activity. As a result, the geological structural conditions of my country's coalfields have become complex, and the prevention and control of mine dynamic disasters such as coal and gas outbursts are very serious. During the formation and evolution of geological structures, due to differences in activity, joints, fissures, faults (normal, reverse and translation faults) and folds (anticline and syncline folds) will be generated in the coal rock body, resulting in the heterogeneity of the coal rock body, affecting the stress state of the coal rock body, the physical and mechanical properties of coal, and the occurrence and migration characteristics of gas in the coal rock layer. Coal mining activities in this structural-stress-gas coupled heterogeneous environment will aggravate the heterogeneous characteristics of the coal rock body. Once the nonlinear characteristics generated by external disturbances exceed the critical value, a new equilibrium state will be reached in the form of coal and gas outbursts. Therefore, only by understanding the heterogeneous characteristics of coal rock mass under the coupling of structure, stress and gas and its formation process, and studying the occurrence and development process of coal and gas outbursts from the essence, can we take effective predictive and preventive measures for coal mine disasters.

[0003] According to the existing relevant literature, the domestic published patents and literature have done some research on the simulation of coal and gas outburst under different geological structures. The Chinese invention patent with application number 201910281874.1 discloses a method for simulating coal and gas outburst in coal-bearing strata containing faults. The invention mainly uses similar materials and similar models to prepare coal-bearing strata containing faults, adopts a loading method of static loading first and then dynamic loading, and loads coal and rock bodies with multiple stress waves, which can realize two-dimensional dynamic and static combined stress loading to induce outburst. However, the coal-bearing strata with faults need to be prepared according to similar models, which is more complicated to prepare and the simulated geological environment is relatively single, and it is impossible to truly simulate the formation and evolution process of the structure. The Chinese invention patent with application number 202110835584.9 discloses a normal fault physical simulation test device and method for coal and gas outburst simulation test. The invention is mainly composed of a retractable baffle and a foldable connection structure, which can realize the simultaneous production of simulated coal and rock strata and normal faults, avoiding the influence caused by different production orders. However, the test device can only produce normal faults, but cannot produce geological structures such as reverse faults, parallel faults and folds, and the test device cannot achieve the integration of fault production and gas outburst simulation.

[0004] Therefore, in order to simulate the effects of tectonic stress on the formation of coal and rock strata in different geological environments and to simulate outbursts in different geological structures, it is urgent to propose a tectonic-stress-gas coupling-induced coal and gas outburst test device and method. Summary of the invention

[0005] The purpose of the present invention is to provide a structure-stress-gas coupling induced coal and gas outburst test device and method to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides a tectonic-stress-gas coupling induced coal and gas outburst test device, comprising a box body, the interior of the box body is filled with rock samples and coal samples, a loading device is installed on the box body, the rock samples and the coal samples are formed by the loading device to form a coal rock layer, and the loading device is used to control the axial pressure and confining pressure of the coal rock layer; a plurality of gas injection holes are arranged on the box wall of the box body, and the box body is connected to a high-pressure gas cylinder and a vacuum pump through pipelines and the plurality of gas injection holes; an air bag is arranged inside the box body, and the air bag is respectively arranged at the top and bottom of the coal rock layer, and the air bag is used to fill the gap between the box body and the coal rock layer; a sensor hole for installing a sensor is opened on one side wall of the box body; a base with a protruding port is installed at one end of the box body, and the base is arranged opposite to the loading device for applying axial pressure; a computer is arranged on the outside of the box body, and the loading device and the sensor are electrically connected to the computer.

[0007] Preferably, the loading device includes a hydraulic loading device for applying axial pressure to the coal rock layer and a hydraulic loading device for applying confining pressure to the coal rock layer.

[0008] Preferably, the airbag is made of a material that has no adsorption effect on gas.

[0009] Preferably, the sensors include a temperature sensor, a gas pressure sensor, a stress sensor, a displacement sensor and a pore pressure sensor.

[0010] A method for using a tectonic-stress-gas coupling induced coal and gas outburst test device comprises the following steps:

[0011] S1. In situ simulation of structural formation and evolution;

[0012] The rock samples and coal samples required for the coal-rock layer are laid in the box, and explosives are laid at predetermined positions of the coal-rock layer, and the laid rock samples and coal samples are formed by using a loading device;

[0013] Sensors are installed on the box, and the stress required for the test is applied to the coal and rock layers using a loading device to simulate different geological structural environments;

[0014] S2, heterogeneous gas environment simulation;

[0015] Place air bags at the top and bottom of the box, install a base with a protruding opening, check that the air tightness of the box is qualified, evacuate the box, then expand the air bags to fill the remaining space in the box, and inject gas into the coal and rock layers to a predetermined pressure to simulate the heterogeneous distribution characteristics of gas in geological structures;

[0016] S3, dynamic load disturbance form actively induces protrusion;

[0017] Detonating explosives actively induces outburst in the form of dynamic load;

[0018] S4, post-test processing;

[0019] The test device was dismantled, the deformation characteristics and protruding hole characteristics of the coal and rock layers were recorded, and the coal and rock layers in the box were cleaned.

[0020] Preferably, the simulation of different geological structural environments, wherein the geological structural environment is one of a normal fault, a reverse fault, a strike-slip fault, anticline fold and syncline fold.

[0021] Preferably, the rock samples and coal samples required for the coal rock layer are laid in the box, wherein the rock samples and coal samples are made by crushing and screening the original rocks and coals, and then adding relevant materials according to test requirements.

[0022] Preferably, the detonation charge actively induces protrusion in the form of dynamic load, and if it does not occur, the stress distribution of the structure in S1 is changed until protrusion occurs.

[0023] Preferably, the detonation of explosives actively induces protrusion in the form of dynamic load. If it does not occur, the initial gas pressure in S2 and the gas pressure distribution in the structure are changed until the protrusion occurs.

[0024] Preferably, the detonation of explosives actively induces outburst in the form of dynamic load, and if it does not occur, the strength and hardness of the coal stratum and the energy of the explosives are changed until outburst occurs.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] 1. The present invention proposes a test device and method for truly simulating coal and gas outburst induced by structural-stress-gas coupling under different geological environments. The device can simulate the loading damage of in-situ stress on the formation of faults and folds in coal and rock strata, the evolution process of tectonic stress, the in-situ stress distribution characteristics in the structure, the stress zoning characteristics when stress concentration occurs in anticlines and synclines, and the heterogeneous distribution characteristics of gas in the geological environment. The test parameters such as stress, gas pressure and deformation of coal and rock strata of the test device can be adjusted according to the test needs, so as to determine the critical stress, critical gas pressure and deformation characteristics of coal and rock strata induced by dynamic loads under different geological environments.

[0027] 2. Air bags that do not absorb gas are placed on the top and bottom of the box. The air bags are easily deformed after expansion and can change with the changes in the structure to ensure that the remaining space in the box is always filled, so that the gas is stored in the coal rock layer in the form of free, seepage and adsorption, simulating the storage form of gas in different geological environments. The position of the gas injection hole, the gas injection rate and the adsorption time can be adjusted to simulate the heterogeneous distribution characteristics of gas in the geological structure environment.

[0028] 3. The test process takes into account the influence of stress and gas coupling on coal outburst under different structures, detonates the explosives laid at the predetermined position in the coal rock layer, destroys the coal rock layer and the raw coal that acts as a seal, and actively induces coal outburst in the form of dynamic load in the structure-stress-gas coupling. The test can explore the influence of different structures, stress distribution, gas distribution, explosive energy and physical properties of raw coal on coal and gas outburst.

[0029] 4. The sensor hole can be installed with temperature sensors, pressure sensors, stress sensors, displacement sensors and pore pressure sensors, which can monitor in real time the changes in parameters such as temperature, pressure, stress, displacement of coal rock layers and pore pressure during the in-situ simulation of the evolution of tectonic stress when different geological environments of coal rock layers are formed, and during the test, analyze the change characteristics of pore cracks in coal rock layers under dynamic load disturbance, the continuous instability and destruction characteristics of coal rock layers, and the energy evolution characteristics, so as to provide guidance for the safe mining of coal mines under different actual geological environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a schematic diagram of the test device for coal and gas outburst induced by structure-stress-gas coupling of the present invention;

[0032] Figure 2 It is a front cross-sectional view of the test device containing the air bag and the coal rock layer of the present invention;

[0033] Figure 3 It is a left sectional view of the test device containing the expansion air bag and the coal rock layer of the present invention;

[0034] Figure 4 It is a front cross-sectional view of the test device of the present invention including the expansion airbag and the normal fault;

[0035] Figure 5 It is a front cross-sectional view of the test device containing the expansion airbag and the reverse fault of the present invention;

[0036] Figure 6 It is a left sectional view of the test device containing the expansion airbag and the translation fault of the present invention;

[0037] Figure 7 It is a front cross-sectional view of the anticline fold test device including the expansion airbag and the stress distribution state of the present invention;

[0038] Figure 8 It is a front cross-sectional view of the syncline fold test device including the expansion airbag and the stress distribution state of the present invention;

[0039] In the figure: 1, box body; 2-26, hydraulic loading device; 27-30, gas injection hole; 31-32, high-pressure gas cylinder; 33, vacuum pump; 34-35, air bag; 36, coal rock layer; 37, raw coal; 38, protrusion; 39-47, sensor hole; 48, computer. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0041] like Figures 1 to 3 As shown, the present invention provides a structure-stress-gas coupling induced coal and gas outburst test device, including a box body 1, 8 hydraulic loading devices 2-9 are arranged on the top of the box body 1, 8 hydraulic loading devices 10-17 are also arranged on the bottom of the box body 1, a hydraulic loading device 18 is arranged on the left end of the box body 1, 4 hydraulic loading devices 19-22 are arranged on the front end of the box body 1, and 4 hydraulic loading devices 23-26 are also arranged on the rear end of the box body 1. The displacement and stress loading value of each hydraulic loading device 2-26 can be set separately or in combination according to the test needs. The hydraulic loading device 18 at the left end can control the axial pressure of the coal rock layer, and the hydraulic loading devices 2-23 at the top can control the axial pressure of the coal rock layer. 9. The hydraulic loading devices 10-17 at the bottom, the hydraulic loading devices 19-22 at the front end and the hydraulic loading devices 23-26 at the rear end can control the confining pressure of the coal and rock layers. The hydraulic loading devices 2-26 can be combined to form coal samples and simulate the ground stress in the coal seams. The top and bottom hydraulic loading devices 2-9, 10-17 can be combined to simulate the formation of normal faults, reverse faults, syncline folds and anticline folds, the tectonic stress evolution process and the in-situ stress distribution characteristics after the formation of the structure. The front and rear hydraulic loading devices 19-22, 23-26 can be combined to simulate the formation of strike-slip faults, the tectonic stress evolution process and the in-situ stress distribution characteristics after the formation of the structure.

[0042] Gas injection holes 27 and 28 are provided on the top of the box body 1, and gas injection holes 29 and 30 are provided on the bottom of the box body 1. The gas injection holes 27-30 can be connected to high-pressure gas cylinders 31 and 32 and a vacuum pump 33 through pipelines to transport and discharge gas respectively. The positions of the gas injection holes 27-30, the gas injection rate and the adsorption time are adjusted to simulate the heterogeneous distribution characteristics of gas under different geological environments. Air bags 34 and 35 are provided on the top and bottom of the box body 1. After the structure is formed, the air bags 34 and 35 expand to fill the remaining space of the box body 1. The air bags 34 and 35 have no adsorption effect on the gas, so as to avoid the gas from being stored in the space outside the coal rock layer 36, and can ensure that the gas is stored in the coal rock layer 36 in the form of seepage, diffusion and adsorption. When the displacement change of the hydraulic loading device 2-26 causes the coal rock layer 36 and the remaining space of the box body 1 to change, the air bags 34 and 35 can also change accordingly and continue to fill the remaining space of the box body 1 to limit the gas in the coal rock layer 36;

[0043] When the coal-rock layer 36 is laid, explosives are laid at a predetermined position according to test requirements, and the low-permeability, high-strength raw coal 37 is fully contacted with the base with a protruding opening 38 at the right end of the coal-rock layer 36 to achieve gas sealing. The explosives are detonated to destroy the coal-rock layer 36 and the raw coal 37 in the form of dynamic load disturbance to actively induce protrusion. The sensor holes 39 to 47 at the front end of the box 1 can be installed with temperature sensors, gas pressure sensors, stress sensors, displacement sensors and pore pressure sensors according to test requirements. The sensors and computer 48 are used to control the device and collect data, and the hydraulic loading devices 2 to 26 can be controlled to simulate different geological structure environments.

[0044] A method for using a tectonic-stress-gas coupling induced coal and gas outburst test device comprises the following steps:

[0045] S1. In situ simulation of structural formation and evolution;

[0046] 1.1. After the original rock and coal are crushed and screened, relevant materials are added according to the test requirements to make rock samples and coal samples. When laying the coal-rock layer 36, explosives are laid at the predetermined position and corresponding sensors are installed in the sensor holes 39-47 to simulate the dynamic load induction in the coal-rock layer 36;

[0047] 1.2. Using the computer 48 to control the hydraulic loading devices 2 to 26 to shape the coal and rock layers according to the shaping pressure required for the test;

[0048] 1.3. From the front cross-sectional view, the computer 48 is used to control the hydraulic loading devices 2-5 and 14-17 to move upward to the test scheme setting position, and the hydraulic loading devices 6-13 are controlled to move downward to the test scheme setting position, and the stress required for the test is applied to the coal and rock layers to form a normal fault, such as Figure 4As shown, during the test, the displacement and stress loading value of the hydraulic loading device are recorded by the data acquisition device to reflect the deformation and failure characteristics of the coal and rock, the structural stress evolution characteristics and the in-situ stress distribution characteristics;

[0049] 1.4. From the front cross-sectional view, the computer 48 is used to control the hydraulic loading devices 2-5 and 14-17 to move downward to the test scheme setting position, and the hydraulic loading devices 6-13 are controlled to move upward to the test scheme setting position, and the stress required for the test is applied to the coal and rock layers to form a reverse fault, such as Figure 5 As shown, during the test, the displacement and stress loading value of the hydraulic loading device are recorded by the data acquisition device to reflect the deformation and failure characteristics of the coal and rock, the structural stress evolution characteristics and the in-situ stress distribution characteristics;

[0050] 1.5. From the left sectional view, the computer 48 is used to control the hydraulic loading devices 19, 20 and 25, 26 to move rightward and leftward to the test scheme setting position, and to control the hydraulic loading devices 21-24 to move leftward and rightward to the test scheme setting position, and to apply the stress required for the test to the coal and rock formations to form a translation fault, such as Figure 6 As shown, during the test, the displacement and stress loading value of the hydraulic loading device are recorded by the data acquisition device to reflect the deformation and failure characteristics of the coal and rock, the structural stress evolution characteristics and the in-situ stress distribution characteristics;

[0051] 1.6. By Figure 2 It can be seen that in the initial state, the distance between the hydraulic loading devices 2 to 9 and the top of the box 1 is L1, and the distance between the hydraulic loading devices 10 to 17 and the bottom of the box 1 is L2. From the front cross-sectional view, the computer 48 is used to control the hydraulic loading devices 5, 6, 13, and 14 to move upward by x1 to the test scheme setting position, the computer 48 is used to control the hydraulic loading devices 4, 7, 12, and 15 to move upward by x2 to the test scheme setting position, the computer 48 is used to control the hydraulic loading devices 3, 8, 11, and 16 to move upward by x3 to the test scheme setting position, and the computer 48 is used to control the hydraulic loading devices 2, 9, 11, and 17 to move upward by x4 to the test scheme setting position, and the stress required for the test is applied to the coal and rock layers to form anticline folds, where x1>x2>x3>x4, as shown in FIG. Figure 7 As shown, during the test, the displacement and stress loading value of the hydraulic loading device are recorded by the data acquisition device to reflect the deformation and failure characteristics of the coal and rock, the structural stress evolution characteristics and the in-situ stress distribution characteristics;

[0052] 1.7. By Figure 2It can be seen that in the initial state, the distance between the hydraulic loading devices 2 to 9 and the top of the box 1 is L1, and the distance between the hydraulic loading devices 10 to 17 and the bottom of the box 1 is L2. From the front cross-sectional view, the computer 48 is used to control the hydraulic loading devices 5, 6, 13, and 14 to move down by x5 to the test scheme setting position, the computer 48 is used to control the hydraulic loading devices 4, 7, 12, and 15 to move down by x6 to the test scheme setting position, the computer 48 is used to control the hydraulic loading devices 3, 8, 11, and 16 to move down by x7 to the test scheme setting position, and the computer 48 is used to control the hydraulic loading devices 2, 9, 11, and 17 to move down by x8 to the test scheme setting position, and the stress required for the test is applied to the coal and rock layers to form syncline folds, where x5>x6>x7>x8, as shown in FIG. Figure 8 As shown, during the test, the displacement and stress loading value of the hydraulic loading device are recorded by the data acquisition device to reflect the deformation and failure characteristics of the coal and rock, the structural stress evolution characteristics and the in-situ stress distribution characteristics;

[0053] 1.8. Determine the support pressure limit equilibrium zone, i.e., the length of the plastic zone is X0, the length of the elastic zone is X1, the length of the original rock stress zone is X2, the stress of the coal rock layer 36 close to the original coal 37 is σ1, the support pressure peak is σ2, and the original stress is σ0, wherein σ2>σ0>σ1, and control the hydraulic loading devices 2 to 17 to change the stress state of the anticline and syncline folds formed in steps 1.6 and 1.7. From the coal rock layer 36 close to the original coal 37 to the support pressure peak position, the vertical stress increases from σ1 to σ2, and from the support pressure peak position to the initial point of the original rock stress, the vertical stress decreases from σ2 to σ0, and the vertical stress remains unchanged at σ0. The length of this area is X2, such as Figure 7 , 8 As shown;

[0054] S2, heterogeneous gas environment simulation;

[0055] 2.1. Place air bags 34 and 35 at the top and bottom of the box 1, and make the raw coal 37 with low permeability and high strength closely contact with the base with the protruding opening 38 at the right end of the coal rock layer 36 to achieve gas sealing. Use high-pressure gas cylinders 31 and 32 to inject gas into the box 1 through the gas injection holes 27-30. After a period of stability, observe the gas pressure reading of the coal rock layer 36 on the computer 48. If the gas pressure reading changes, it means that the box is leaking, and the leaking part needs to be found and sealed. Otherwise, it means that the air tightness is good.

[0056] 2.2. After the air tightness inspection is completed, the box 1 is evacuated through the gas injection holes 27-30 by using a vacuum pump, and then the inflated airbags 34 and 35 are filled into the remaining space of the box 1. The airbags 34 and 35 do not have adsorption properties to gas, ensuring that the gas is stored in the coal rock layer 36 in the form of diffusion, seepage and adsorption. The airbags 34 and 35 are easily deformable, and the inflated airbags 34 and 35 can change with the changes in the structural environment to ensure that the remaining space of the box 1 can always be filled. The high-pressure gas cylinders 31 and 32 are used to inject gas into the coal rock layer 36 through the gas injection holes 27-30 to a predetermined pressure, and the air pressure changes in different areas are controlled by the position of the gas injection holes, the gas injection rate and the adsorption time to simulate the heterogeneous distribution characteristics of gas in the geological structure;

[0057] S3, dynamic load disturbance form actively induces protrusion;

[0058] Detonate the explosive to actively induce outburst in the form of dynamic load, and observe whether outburst occurs. If not, repeat step 1.8 to change the stress distribution of the structure or repeat step 2.2 to change the initial gas pressure and the gas pressure distribution in the structure until outburst occurs, and record the structural stress evolution characteristics, in-situ stress distribution characteristics, coal and rock formation deformation characteristics, stress change characteristics under dynamic load disturbance and critical gas pressure during the test. Alternatively, when conducting the next test, change the raw coal strength and hardness and the explosive energy, and repeat steps S1 and S2 until outburst occurs, and study the influence of raw coal properties and explosive energy on active induction of outburst in the form of dynamic load disturbance in the structural environment;

[0059] S4, post-test processing;

[0060] 4.1. Count the mass and particle size distribution of the protruding coal powder in different areas and clean up the protruding coal powder, remove the temperature, gas pressure, stress, displacement, pore pressure sensor wiring and gas pipeline, take pictures and record the deformation characteristics of the coal rock layer 36, the protruding hole characteristics and clean up the coal rock layer 36 in the box 1;

[0061] 4.2. Analyze the evolution characteristics of tectonic stress and the distribution characteristics of in-situ stress during the formation of geological structures. Analyze the change law of pores and cracks in coal and rock strata after dynamic load disturbance based on the change characteristics of pore pressure after detonation of explosives. Analyze the influence of pressure relief zone, concentrated stress zone and original rock stress zone formed when stress concentration occurs in anticline and syncline folds on outburst. Analyze the stress change and deformation of coal and rock strata during the test and calculate the elastic energy of coal and rock strata. Analyze the change of air pressure during the test and calculate the gas expansion energy. Analyze the layer cracking characteristics of coal body in combination with the characteristics of stress and air pressure change and coal body destruction characteristics. Analyze the mass and particle size distribution characteristics of outburst coal powder and calculate the crushing work and ejection work of outburst coal. Determine the critical stress and critical gas pressure during outburst based on the continuous instability and destruction characteristics of coal body and the relationship between energy source and energy dissipation.

[0062] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A test device for coal and gas outburst induced by structural-stress-gas coupling, characterized in that: The invention comprises a box (1), wherein the interior of the box (1) is filled with rock samples and coal samples, and a loading device is installed on the box (1). The rock samples and coal samples are shaped by the loading device to form a coal rock layer (36), and the loading device is used to control the axial pressure and confining pressure of the coal rock layer (36); a plurality of gas injection holes are arranged on the box wall of the box (1), and the box (1) is connected to a high-pressure gas cylinder (31, 32) and a vacuum pump (33) through pipelines and the plurality of gas injection holes; an air bag (34, 35) is arranged inside the box (1), and the air bag (34, 35) 4, 35) are respectively arranged at the top and bottom of the coal rock layer (36), and the air bags (34, 35) are used to fill the gap between the box body (1) and the coal rock layer (36); a sensor hole (39-47) for installing a sensor is opened on one side wall of the box body (1); a base with a protruding opening (38) is installed at one end of the box body (1), and the base is arranged opposite to the loading device for applying axial pressure; a computer (48) is arranged on the outside of the box body (1), and the loading device and the sensor are electrically connected to the computer (48).

2. The test device for coal and gas outburst induced by structural-stress-gas coupling according to claim 1 is characterized in that: The loading device comprises a hydraulic loading device (18) for applying axial pressure to the coal rock layer (36) and a hydraulic loading device (2-9, 10-17, 19-22, 23-26) for applying confining pressure to the coal rock layer (36).

3. The test device for coal and gas outburst induced by structural-stress-gas coupling according to claim 1, characterized in that: The airbags (34, 35) are made of a material that has no adsorption effect on gas.

4. The test device for coal and gas outburst induced by structural-stress-gas coupling according to claim 1, characterized in that: The sensors include a temperature sensor, a gas pressure sensor, a stress sensor, a displacement sensor and a pore pressure sensor.

5. A method for using the structure-stress-gas coupling induced coal and gas outburst test device according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. In situ simulation of structural formation and evolution; The rock samples and coal samples required for the coal-rock layer (36) are laid in the box (1), and explosives are laid at predetermined positions of the coal-rock layer (36), and the laid rock samples and coal samples are shaped by using a loading device; A sensor is installed on the box (1), and a loading device is used to apply stress required for the test to the coal rock layer (36) to simulate different geological structure environments; S2, simulation of heterogeneous gas environment; Air bags (34, 35) are placed at the top and bottom of the box (1), and a base with a protruding opening (38) is installed. After checking that the air tightness of the box (1) is qualified, the box (1) is evacuated, and then the air bags (34, 35) are expanded to fill the remaining space of the box (1), and gas is injected into the coal rock layer (36) to a predetermined pressure to simulate the heterogeneous distribution characteristics of gas in the geological structure; S3, dynamic load disturbance form actively induces protrusion; Detonating explosives actively induces outburst in the form of dynamic load; S4, post-test processing; The test device is dismantled, the deformation characteristics and the protruding hole characteristics of the coal-rock layer (36) are recorded, and the coal-rock layer (36) in the box (1) is cleaned.

6. The method of using the structure-stress-gas coupling induced coal and gas outburst test device according to claim 5, characterized in that: The simulated different geological structure environments, wherein the geological structure environment is one of normal faults, reverse faults, strike-slip faults, anticline folds and syncline folds.

7. The method of using the structure-stress-gas coupling induced coal and gas outburst test device according to claim 5, characterized in that: The rock samples and coal samples required for the coal rock layer (36) are laid in the box (1), wherein the rock samples and coal samples are made by crushing and screening the original rocks and coals, and then adding relevant materials according to test requirements.

8. The method of using the structure-stress-gas coupling induced coal and gas outburst test device according to claim 5, characterized in that: The detonation charge actively induces protrusion in the form of dynamic load. If it does not occur, the stress distribution of the structure in S1 is changed until protrusion occurs.

9. The method of using the structure-stress-gas coupling induced coal and gas outburst test device according to claim 5, characterized in that: The detonation of explosives actively induces outburst in the form of dynamic load. If it does not occur, the initial air pressure in S2 and the air pressure distribution in the structure are changed until outburst occurs.

10. The method of using the structure-stress-gas coupling induced coal and gas outburst test device according to claim 5, characterized in that: The detonation of explosives actively induces outburst in the form of dynamic load. If it does not occur, the strength and hardness of the coal rock layer (36) and the energy of the explosives are changed until outburst occurs.

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