High-pressure air combustion stamping fracturing coal rock experiment system and use method

Abstract

The invention provides a high-pressure air combustion stamping fracturing coal rock experiment system and a use method, and relates to the technical field of rock mechanics test equipment, the high-pressure air combustion stamping fracturing coal rock experiment system comprises a high-pressure air combustion stamping fracturing device and a variable-size coal rock true triaxial experiment device, the high-pressure gas generator is used for generating high-pressure gas so as to realize impact fracturing of coal and rock masses; the invention discloses a variable-size coal rock true triaxial experiment device which is used for carrying out true triaxial pressurization unloading experiments on coal rock masses with different sizes. And the variable-size coal rock true triaxial experimental device is connected with the high-pressure air combustion stamping fracturing device through a breather pipe. The high-pressure air combustion stamping fracturing device generates high-pressure shock waves and ultrahigh-pressure high-temperature gas within a short time to impact and fracture the coal rock mass, and compared with a traditional fracturing technology, the coal-rock mass fracturing device has the characteristics that the fracturing pressure is great, fracture lines generated by rock breaking are more complex, and the permeability increasing effect on the coal seam is more remarkable.

Description

Technical Field

[0001] The present invention relates to the technical field of rock mechanics testing equipment, and in particular to a high-pressure air combustion punching cracking coal rock experimental system and a use method thereof. Background Art

[0002] A large number of coal seams in my country have poor permeability and generally low permeability. Coal mine gas disasters occur frequently, causing serious economic losses. By strengthening gas extraction, we can effectively ensure mine safety and reduce gas accidents. At the same time, we can also reduce greenhouse gas emissions, optimize my country's energy structure, and promote the development of the clean energy industry.

[0003] How to increase the permeability of low-permeability coal seams through fracturing has become a bottleneck restricting coal seam gas extraction in coal mining areas. At present, technical means such as blasting fracturing, hydraulic fracturing, and CO2 phase change fracturing have been formed for coal seam fracturing and permeability enhancement, but these technologies also have some problems. For example, the traditional explosive blasting has a small blasting fracturing range under a three-dimensional high ground stress environment, and the underground explosive blasting in coal mines is strictly controlled, has many restrictions, poor safety, and complex operation procedures; hydraulic fracturing often makes it difficult to control the direction of hydraulic fracturing and it is difficult to fracture the formation uniformly for complex geological conditions and non-uniform formations, especially for high-gas soft coal seams, slow pressurization, easy to compact the coal body and difficult to fracture the coal seam proppant is easy to embed in the coal body; CO2 phase change fracturing requires the use of a special liquid CO2 storage device and a phase change excitation mechanism, the application cost is high, CO2 has a greenhouse effect, and the high CO2 content in the coal seam is prone to outbursts, and the fracturing process is complex and there are certain risks, which is difficult for coal mine site operators to master.

[0004] The high-pressure air combustion stamping fracturing method is to stimulate the combustion of energy-gathering agents to release a large amount of heat energy to achieve air fluid pressurization, quickly generate high-pressure shock waves to fracture the coal rock mass to form radial cracks and broken areas, and at the same time generate high-pressure and high-temperature gas to expand the cracks and broken areas to achieve efficient fracturing. Compared with traditional blasting methods, the fracturing range is easier to control and has better safety performance; compared with hydraulic fracturing technology, it has the characteristics of more complex crack patterns and better permeability enhancement effect; compared with CO2 phase change fracturing method, it has the advantage of easy collection and transportation of materials. Therefore, the invention of a high-pressure air combustion stamping fracturing coal rock experimental system and use method can not only reduce costs, reduce pollution, and greatly improve construction safety, but also adapt to complex coalbed methane mining processes and greatly improve mining efficiency.

[0005] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0006] In view of this, the present invention provides a high-pressure air combustion ramming cracking coal rock experimental system and a method of use to solve the above-mentioned problems.

[0007] In order to solve the above problems, the specific technical solutions adopted by the present invention are as follows: According to one aspect of the present invention, a high-pressure air combustion punching and fracturing coal rock experimental system is provided, comprising: a high-pressure air combustion punching and fracturing device and a variable-size coal rock true triaxial experimental device, wherein the high-pressure air combustion punching and fracturing device is used to generate high-pressure gas to achieve impact fracturing of coal rock mass; the variable-size coal rock true triaxial experimental device is used to perform true triaxial pressurization and unloading experiments on coal rock mass of different sizes (maximum 500mm*500mm*500mm); the variable-size coal rock true triaxial experimental device and the high-pressure air combustion punching and fracturing device are connected via a ventilation pipe; Furthermore, in order to generate high-pressure gas to achieve impact fracturing of coal and rock, the air is first pressurized by a gas booster system, and the energy-gathering agent is quickly burned after excitation, releasing a large amount of heat energy to enable the air fluid to quickly generate a high-pressure shock wave and ultra-high-pressure and high-temperature gas to impact and fracture the coal and rock (up to 150MPa), thereby achieving an efficient rock breaking effect. The temperature and pressure sensor can accurately measure the gas temperature and pressure in the energy-gathering agent cabin to ensure precise control of the operation process. The design of the fracturing device plugging cap can facilitate the opening of the energy-gathering agent cabin to input the energy-gathering agent, thereby increasing the flexibility of use. The high-pressure air combustion ram fracturing device includes an energy-gathering agent cabin, and a gas booster system is provided at one end of the energy-gathering agent cabin. A system is provided, a fracturing device cap is embedded in the side wall of one end of the energy-gathering agent cabin, and an active and passive integrated sealing wire assembly is arranged inside the fracturing device cap; a one-way valve and a connecting port 1 are arranged in sequence on the outside of the gas pressurization system along the direction close to the energy-gathering agent cabin, and a temperature and pressure sensor 1 is arranged on the outside of the connecting port 1; an energy-gathering agent is arranged inside the energy-gathering agent cabin; a pressure relief slider is arranged inside the other end of the energy-gathering agent cabin, a gas outlet connected to the air inlet end of the ventilation pipe is provided on the outside of the other end of the energy-gathering agent cabin, a connecting port 2 is arranged on one side of the gas outlet, and a temperature and pressure sensor 2 is arranged on one side of the connecting port 2; a hydraulic oil inlet is provided on the side wall of the other end of the energy-gathering agent cabin, and a hydraulic pump 1 is connected to one end of the hydraulic oil inlet.

[0008] Furthermore, in order to transmit electrical signals to excite the energy-gathering agent, ensure the sealing of the device, prevent gas leakage, and improve safety, the active and passive integrated sealed wire assembly includes a nut with a hole symmetrically arranged inside the fracturing device cap, a copper rod is penetrated through the middle of the nut with a hole, and a sealing gasket is arranged between the nut with a hole and the fracturing device cap; copper rod sealing sections are arranged at both ends of the copper rod, and a winding groove is arranged on the outer side of one end of the copper rod sealing section; the outer side of the copper rod is coated with insulating paint and silicone high-temperature resistant paint from the inside to the outside; a thread matching the nut with a hole is arranged inside the fracturing device cap; a chamfer is arranged at one end of the pressure relief slider, and the chamfer is set to 45 degrees.

[0009] Furthermore, in order to provide loading power in the X, Y, and Z directions, so that the experiment can more comprehensively simulate the real ground stress environment and improve the accuracy and reliability of the experiment, through the combined use of pressure plate 1 and pressure plate 2, the device can flexibly pressurize samples of different sizes to meet diverse experimental needs. The rigid frame not only provides safety protection to prevent debris generated by sample rupture from injuring people, but also limits the debris inside the frame to facilitate subsequent processing. The variable-size coal and rock true triaxial experimental device includes a rigid frame, a plurality of hydraulic pumps 2 are arranged on the outside of the rigid frame, a plurality of hydraulic chambers connected to the hydraulic pumps 2 are arranged inside the rigid frame, a plurality of pressure plates 1 are arranged in the middle of the hydraulic chamber, a pressure plate 2 is arranged on one side of the pressure plate 1, and a loading cylinder is arranged on one side of the pressure plate 1 and in the middle of the pressure plate 2; a loading platen is arranged on one side of the pressure plate 2, and a sample is arranged between the loading plates; a ventilation pipe borehole connected to one of the air outlet ends of the ventilation pipe is opened on the side wall of the rigid frame away from one of the hydraulic pumps 2.

[0010] Furthermore, in order to facilitate the installation of acoustic emission sensors and potentiometric sensors on rocks, so as to facilitate various monitoring and measurement tasks and increase the functionality and practicality of the device, installation holes for installing acoustic emission sensors and potentiometric sensors are provided at the four corners of the side walls of loading platen 1 and loading platen 2.

[0011] According to another aspect of the present invention, a method for using the high-pressure air combustion ramming cracking coal rock experimental system is provided, comprising the following steps: S1. Prepare to connect sensors and data acquisition equipment, and place rock samples in the true triaxial experimental device; S2. According to the size of the coal and rock mass, a suitable pressure plate and a loading cylinder to be activated are selected, and confining pressure is applied in the X, Y, and Z directions through the loading cylinder; S3, increase the pressure to the set pressure value of 80Mpa through a pair of pressure relief sliders of the hydraulic pump, and input the air into the energy-gathering agent cabin through the gas boosting system, increase the gas pressure in the energy-gathering agent cabin to 30Mpa, and then close the one-way valve; S4, connecting the wire pre-installed on the active and passive integrated sealed wire assembly to the activator, and igniting the energy-gathering agent through the activator, so that the fluid begins to change phase due to heating; S5. When the fluid is heated and the pressure in the energy-gathering agent cabin reaches a predetermined value of 80 MPa, the pressure relief slider is moved back to relieve the pressure in the energy-gathering agent cabin. The gas in the energy-gathering agent cabin is released through the gas outlet and transported to the selected true triaxial test mechanism through the vent pipe. The temperature and pressure sensor at the gas outlet is used to collect data. S6. The coal-rock sample is cracked and damaged under the action of high-temperature and high-pressure gas. The hydraulic pump applies pressure to the pressure relief slider to close the gas path and release the gas path connection at the gas outlet. S7. When the reaction in the energy-gathering agent cabin is finished, the plugging cap of the fracturing device is opened to discharge the waste residue, and after the waste residue is discharged, the pressure of the hydraulic pump 1 is released, and the pressure relief slider is returned to its position; S8. Clean the debris of coal and rock samples in the true triaxial test apparatus.

[0012] Furthermore, the preparation for connecting the sensor and the data acquisition device and placing the rock sample in the true triaxial test device includes the following steps: S11, open the plugging cap of the fracturing device, input the energy-gathering agent into the energy-gathering agent cabin and connect it to the excitation end, then screw on the plugging cap of the fracturing device, install and tighten the active and passive integrated sealed wire assembly; S12, connecting the temperature and pressure sensor 1 and the temperature and pressure sensor 2 to the data acquisition instrument and the computer; S23. The rock sample with the middle hole processed is placed in the true triaxial experimental device by means of a loading and unloading trolley and a hydraulic crane, and the acoustic emission sensor and the potential sensor are installed on the surface of the rock sample through the installation drilled hole.

[0013] The beneficial effects of the present invention are: 1. The fracturing and rock breaking effects are remarkable. The present invention uses a high-pressure air combustion stamping fracturing device to generate high-pressure shock waves and ultra-high-pressure and high-temperature gas shock to fracture coal and rock in a short time. Compared with traditional fracturing technology, it has the characteristics of extremely high fracturing pressure (up to 150MPa), more complex crack patterns produced by rock breaking, and more significant effect on increasing the permeability of coal seams.

[0014] 2. Improve safety. The use of active and passive integrated sealed wire components can ensure the sealing of the device in a high-pressure environment while transmitting electrical signals and stimulating the energy-gathering agent, thereby preventing gas leakage and improving safety.

[0015] 3. It is green and low-cost. It uses high-pressure air for fracturing, has strong applicability, low material cost, and the collection and use process is safer and more convenient. It does not produce harmful gases after the reaction, reducing pollution to the environment.

[0016] 4. Through the high-pressure air combustion ramming cracking coal rock experimental system, the research on the cracking effect of high-temperature and high-pressure gas on coal and rock masses of different scales and its fluid-solid-heat coupling mechanism can be effectively realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. 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 creative work. In the drawings: Figure 12 is a schematic structural diagram of a high-pressure air combustion ramming cracking coal rock experimental system according to an embodiment of the present invention; Figure 2 2 is a schematic structural diagram of a high-pressure air combustion ram fracturing device in a high-pressure air combustion ram fracturing coal rock experimental system according to an embodiment of the present invention; Figure 3 2 is a schematic structural diagram of an active and passive integrated sealed wire assembly in a high-pressure air combustion ramming cracking coal rock experimental system according to an embodiment of the present invention; Figure 4 2 is a schematic diagram of the structure of a copper rod in a high-pressure air combustion punching cracking coal rock experimental system according to an embodiment of the present invention; Figure 5 2 is a schematic structural diagram of a coal-rock true triaxial test device in a high-pressure air combustion ramming cracking coal-rock test system according to an embodiment of the present invention; Figure 6 It is a structural schematic diagram of the first and second pressure plate loading cylinders in the high-pressure air combustion punching and cracking coal and rock experimental system according to an embodiment of the present invention; Figure 7 2 is a schematic diagram of the structure of a loading plate in a high-pressure air combustion punching and cracking coal rock experimental system according to an embodiment of the present invention; Figure 8 It is a flow chart of the method of using the high-pressure air combustion stamping fracture coal rock experimental system according to an embodiment of the present invention.

[0018] In the figure: 1. High-pressure air combustion ram fracturing device; 101. Energy-gathering agent cabin; 102. Gas pressurization system; 103. Fracturing device plugging cap; 1031. Thread; 104. Active and passive integrated sealing wire assembly; 1041. Nut with hole; 1042. Copper rod; 10421. Copper rod sealing section; 10422. Winding groove; 1043. Sealing gasket; 105. One-way valve; 106. Connection port 1; 107. Temperature and pressure sensor 1; 108. Energy-gathering agent; 109. Pressure relief slide block; 1010, gas outlet; 1011, connection port 2; 1012, temperature and pressure sensor 2; 1013, hydraulic oil inlet; 1014, hydraulic pump 1; 2, variable size coal and rock true triaxial experimental device; 201, rigid frame; 202, hydraulic pump 2; 203, hydraulic chamber; 204, pressure plate 1; 205, pressure plate 2; 206, loading cylinder; 207, loading pressure plate; 2071, installation drilling; 208, specimen; 209, ventilation pipe drilling; 3, ventilation pipe. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0020] According to an embodiment of the present invention, a high-pressure air combustion ramming cracking coal rock experimental system and a method for using the system are provided.

[0021] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1-Figure 7 As shown, according to one embodiment of the present invention, a high-pressure air combustion punching and fracturing coal rock experimental system is provided, and the high-pressure air combustion punching and fracturing coal rock experimental system comprises: a high-pressure air combustion punching and fracturing device 1, and a variable-size coal rock true triaxial experimental device 2, wherein the high-pressure air combustion punching and fracturing device 1 is used to generate high-pressure gas to achieve impact fracturing of rocks; the variable-size coal rock true triaxial experimental device 2 is used to perform true triaxial pressurization and unloading experiments on rocks of different sizes with a maximum size of 500 mm; the variable-size coal rock true triaxial experimental device 2 is connected to the high-pressure air combustion punching and fracturing device 1 through a ventilation pipe 3; the end of the ventilation pipe 3 and the high-pressure air combustion punching and fracturing device 1 is set as an air inlet end, and the end of the ventilation pipe 3 connected to the variable-size coal rock true triaxial experimental device 2 is set as an air outlet end.

[0022] With the help of the above technical scheme, the present invention generates high-pressure gas through the high-pressure air combustion stamping fracturing device 1, which can directly pressurize and fracture the rock sample, which is safer and more efficient. Moreover, through the variable-size coal and rock true triaxial test device 2, true triaxial tests can be performed on coal and rock samples of different sizes, thereby improving the applicability of the high-pressure air combustion stamping fracturing coal and rock true triaxial test device.

[0023] In one embodiment, for the above-mentioned high-pressure air combustion ram fracturing device 1, the high-pressure air combustion ram fracturing device 1 includes an energy-gathering agent cabin 101, a gas pressurizing system 102 is arranged at one end of the energy-gathering agent cabin 101, a fracturing device plugging cap 103 is embedded in the side wall of one end of the energy-gathering agent cabin 101, and an active and passive integrated sealing wire assembly 104 is arranged inside the fracturing device plugging cap 103; a one-way valve 105 and a connection port 106 are arranged in sequence on the outside of the gas pressurizing system 102 along the direction close to the energy-gathering agent cabin 101, and a temperature and pressure sensor 104 is arranged on the outside of the connection port 106. 7; The energy-gathering agent cabin 101 is provided with an energy-gathering agent 108 (the energy-gathering agent 108 is a functional material that can burn rapidly and release a large amount of heat after being stimulated by an electrical signal); a pressure relief slider 109 is provided inside the other end of the energy-gathering agent cabin 101, and a gas outlet 1010 connected to the air inlet end of the vent pipe 3 is provided on the outer side of the other end of the energy-gathering agent cabin 101. In addition, in specific applications, the lower end of the gas outlet 1010 is provided with a 45-degree concave to achieve the cooperation of the pressure relief slider 109, and a connection port 2 1011 is provided on one side of the gas outlet 1010, and the connection port 2 1011 is provided with a A temperature and pressure sensor 1012 is arranged on one side; a hydraulic oil inlet 1013 is arranged on the side wall of the other end of the energy-gathering agent cabin 101, and one end of the hydraulic oil inlet 1013 is connected to a hydraulic pump 1014; the active and passive integrated sealing wire assembly 104 comprises a hole nut 1041 symmetrically arranged inside the fracturing device plugging cap 103 (a larger thread is used inside the hole nut 1041 so that it can be pressed against the fracturing device plugging cap under the action of the high-pressure gas in the energy-gathering agent cabin to achieve passive sealing), and a copper rod 1042 is arranged through the middle of the hole nut 1041 (the copper rod 1042 is used to transmit the signal The invention discloses a novel energy-generating agent, wherein a sealing gasket 1043 is arranged between the hole nut 1041 and the fracturing device plugging cap 103 (the sealing gasket 1043 is made of high temperature resistant glass fiber, which can realize compression sealing, withstand high temperature and high pressure, and is non-conductive); copper rod sealing sections 10421 are arranged at both ends of the copper rod 1042, and a winding groove 10422 is arranged on the outer side of one end of the copper rod sealing section 10421; the outer side of the copper rod 1042 is coated with insulating paint and organic silicon high temperature resistant paint from the inside to the outside in sequence; the interior of the fracturing device plugging cap 103 is provided with a thread 1031 which matches with the hole nut 1041;One end of the pressure relief slider 109 is provided with a chamfer, and the chamfer is set to 45 degrees, so that high-pressure gas can be generated to achieve impact fracturing of rocks. By pressurizing the liquefied gas and rapidly burning the energy-gathering agent after excitation, a large amount of heat energy is released to achieve efficient rock breaking effect. The temperature and pressure sensor 1012 can accurately measure the gas temperature and pressure in the energy-gathering agent cabin 101 to ensure precise control of the operation process. The design of the fracturing device plugging cap 103 can facilitate opening the energy-gathering agent cabin 101 to input the energy-gathering agent, which increases the flexibility of use. At the same time, the active and passive integrated sealed wire assembly 104 can transmit electrical signals and excite the energy-gathering agent 108, and can also ensure the sealing of the device, prevent gas leakage, and improve safety. ;

[0024] In addition, it should be noted that a sealing ring groove is machined on the outside of the pressure relief slider 109 and is equipped with a sealing ring to achieve strict sealing of the cabin. The pressure relief slider 109 can withstand repeated impacts of 1L volume of 150MPa high-temperature and high-pressure air.

[0025] The temperature and pressure sensor 1012 is sealed by a compression-type sealing ring at the installation location, and is a high-precision temperature and pressure sensor 1012.

[0026] Specifically, the gas boosting system 102 liquefies the air by boosting the pressure, the fracturing device plugging cap is used to input the energy-gathering agent into the energy-gathering agent cabin after opening, the energy-gathering agent cabin 101 is used to store the energy-gathering agent, the gas outlet 1010 is used to output high-temperature and high-pressure gas, the active and passive integrated sealed wire assembly is used to transmit electrical signals to excite the energy-gathering agent 108 and ensure that the gas is strictly sealed, the pressure relief slider 109 is used to open and close the gas outlet 1010, the hydraulic oil inlet 1013 is used to input hydraulic oil to apply pressure to the pressure relief slider 109, the hydraulic pump 1014 is used to apply pressure to the hydraulic oil, and the temperature and pressure sensor 107 is composed of a temperature sensor and a The pressure sensor can measure the temperature and pressure of the gas in the energy-gathering agent cabin 101. The connection port 106 and the connection port 2 1011 are used to connect the temperature and pressure sensor 107 with the gas in the energy-gathering agent cabin 101. The one-way valve 105 is used to control the one-way entry of the gas into the energy-gathering agent cabin 101. The energy-gathering agent 108 is used to quickly burn and release a large amount of heat after excitation, and transform the fluid in the energy-gathering agent cabin 101 into gas, causing a violent expansion of the volume and an increase in pressure to achieve a rock-breaking effect. The winding groove 10422 is used to wind the wire and connect it to the energy-gathering agent 108. The copper rod sealing section 10421 is covered with a thermoplastic sleeve to prevent air from entering when the nut is turned.

[0027] The variable-size coal-rock true triaxial experimental device 2 comprises a rigid frame 201, a plurality of hydraulic pumps 202 are arranged on the outside of the rigid frame 201, a plurality of hydraulic chambers 203 connected to the hydraulic pumps 202 are arranged inside the rigid frame 201, a plurality of pressure plates 204 are arranged in the middle of the hydraulic chamber 203, a pressure plate 205 is arranged on one side of the pressure plate 204, and a loading cylinder 206 is arranged on one side of the pressure plate 204 and in the middle of the pressure plate 205; a loading plate 207 is arranged on one side of the pressure plate 205, and a sample 208 is arranged between the loading plate 207; the rigid frame 201 is away from A vent hole 209 connected to one of the air outlet ends of the vent 3 is provided on the side wall of one of the hydraulic pumps 202, thereby providing loading power in the X, Y, and Z directions, so that the experiment can more comprehensively simulate the real ground stress environment and improve the accuracy and reliability of the experiment. Through the combined use of pressure plate 1 204 and pressure plate 2 205, the device can flexibly pressurize samples of different sizes to meet diverse experimental needs. The rigid frame 201 not only provides safety protection to prevent debris generated by sample rupture from injuring people, but also limits the debris to the inside of the frame to facilitate subsequent processing.

[0028] The loading cylinder 206 is used to provide loading power in the X, Y, and Z directions under the action of hydraulic oil. The second pressure plate 205 (large-sized pressure plate) is used to pressurize small-sized samples separately. The first pressure plate 204 (small-sized pressure plate) is used to pressurize large-sized samples together with the second pressure plate 205. The loading pressure plate 207 is used to transmit pressure to the rock sample. The ventilation pipe drilling hole 209 is used to conduct high-temperature and high-pressure gas to the rock sample. The rigid frame 201 is forged from high-quality alloy steel in one piece to provide safety protection to prevent debris generated by sample rupture from injuring people. At the same time, the debris will be limited inside the frame to facilitate subsequent processing. The hydraulic pump 202 provides pressure by delivering hydraulic oil to the hydraulic chamber 203.

[0029] The four corners of the side wall of the loading plate 207 are provided with mounting holes 2071 for mounting the acoustic emission sensor and the potentiometric sensor, so that the acoustic emission sensor and the potentiometric sensor can be easily mounted on the rock, and various monitoring and measuring tasks can be easily performed, thereby increasing the functionality and practicality of the device.

[0030] In addition, it should be noted that the diameter of the mounting bore 2071 is 20 mm, and the loading plate 207 uses a friction-reducing copper sheet to reduce the friction and resistance between the material and the loading end surface, thereby ensuring uniform transmission of the loading force.

[0031] like Figure 8 According to another embodiment of the present invention, a method for using the high-pressure air combustion ramming cracking coal rock experimental system is provided, comprising the following steps: S1. Prepare to connect sensors and data acquisition equipment, and place rock samples in the true triaxial experimental device; Specifically, preparing to connect sensors and data acquisition equipment and placing rock samples in a true triaxial experimental device includes the following steps: S11, open the fracturing device plugging cap 103, input the energy-gathering agent into the energy-gathering agent chamber 101 and connect it to the excitation end, then screw on the fracturing device plugging cap 103, install and tighten the active and passive integrated sealed wire assembly 104; S12, connecting the temperature and pressure sensor 107 and the temperature and pressure sensor 2 1012 to the data acquisition instrument and the computer; S23. Place the rock sample with the middle hole processed in the true triaxial experimental device by using a loading and unloading trolley and a hydraulic crane, and install the acoustic emission sensor and the potential sensor on the surface of the rock sample through the installation borehole 2071.

[0032] S2. According to the size of the coal and rock mass, a suitable pressure plate and a loading cylinder to be activated are selected (the large-sized sample uses all the pressure plate 1 204, the pressure plate 2 205 and the loading cylinder 206, and the small-sized sample only uses the pressure plate 2 205 and the loading cylinder 206 at the center), and the confining pressure is applied in the X, Y, and Z directions through the loading cylinder 206; S3, the pressure relief slider 109 is pressurized to a set pressure value of 80 MPa through the hydraulic pump 1014, and the air is input into the energy-gathering agent cabin 101 through the gas pressurization system 102, the gas pressure in the energy-gathering agent cabin 101 is increased to 30 MPa, and then the one-way valve 105 is closed; S4, connecting the wire pre-installed on the active and passive integrated sealed wire assembly 104 to the activator, and igniting the energy-gathering agent 108 through the activator, so that the fluid begins to change phase due to the heat; S5. When the fluid is heated and the pressure in the energy-gathering chamber 101 reaches a predetermined value of 80 MPa, the pressure relief slider 109 is moved back to relieve the pressure in the energy-gathering chamber 101. The gas in the energy-gathering chamber 101 is released through the gas outlet 1010 and transported to the selected true triaxial test mechanism through the vent pipe 3. The temperature and pressure sensor at the gas outlet 1010 is used to collect data. S6. The coal-rock sample is cracked and damaged under the action of high-temperature and high-pressure gas. The hydraulic pump 1014 applies pressure to the pressure relief slider 109 to close the gas path, and the gas path connection at the gas outlet 1010 is released at the same time. S7, when the reaction in the energy-gathering agent cabin 101 is finished, the fracturing device plugging cap 103 is opened to discharge the waste residue, and after the waste residue is discharged, the pressure of the hydraulic pump 1014 is released, and the pressure relief slider 109 is returned to its original position; S8. Clean the debris of coal and rock samples in the true triaxial test apparatus.

[0033] The test method designed based on the above test device of the present invention releases a large amount of heat energy by stimulating the combustion of the energy-gathering agent to achieve air fluid pressurization, quickly generate high-pressure shock waves to fracture the coal rock mass to form radial cracks and broken areas, and at the same time generate high-temperature and high-pressure gas to expand the cracks and broken areas. Compared with traditional blasting methods, the fracturing range is easier to control and has better safety performance; compared with hydraulic fracturing technology, it has the characteristics of more complex crack patterns and better permeability enhancement effect; compared with CO2 phase change fracturing method, it has the advantage of easy collection and transportation of materials.

[0034] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0035] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. High-pressure air combustion ramming cracking coal rock experimental system, characterized in that: The high-pressure air combustion ramming cracking coal rock experimental system comprises a high-pressure air combustion ramming cracking device (1) and a variable-size coal rock true triaxial experimental device (2), wherein: The high-pressure air combustion impact fracturing device (1) is used to generate high-pressure gas to achieve impact fracturing of coal and rock masses; The variable-size coal-rock true triaxial test device (2) is used to perform true triaxial pressure unloading tests on coal-rock bodies of different sizes; The variable-size coal-rock true triaxial experimental device (2) is connected to the high-pressure air combustion ramming fracturing device (1) via a ventilation pipe (3).

2. The high-pressure air combustion ramming cracking coal rock experimental system according to claim 1 is characterized in that: The high-pressure air combustion ram fracturing device (1) comprises an energy-gathering agent cabin (101), one end of the energy-gathering agent cabin (101) is provided with a gas pressurizing system (102), a side wall of one end of the energy-gathering agent cabin (101) is embedded with a fracturing device plugging cap (103), and an active and passive integrated sealed wire assembly (104) is provided inside the fracturing device plugging cap (103); A one-way valve (105) and a connection port 1 (106) are sequentially arranged on the outside of the gas pressurization system (102) in a direction close to the energy-gathering agent cabin (101), and a temperature and pressure sensor 1 (107) is arranged on the outside of the connection port 1 (106); An energy-gathering agent (108) is arranged inside the energy-gathering agent cabin (101); A pressure relief slider (109) is provided inside the other end of the energy-gathering agent cabin (101), a gas outlet (1010) connected to the air inlet end of the vent pipe (3) is provided on the outside of the other end of the energy-gathering agent cabin (101), a second connection port (1011) is provided on one side of the gas outlet (1010), and a second temperature and pressure sensor (1012) is provided on one side of the second connection port (1011); A hydraulic oil inlet (1013) is provided on the other side wall of the energy-gathering agent cabin (101), and one end of the hydraulic oil inlet (1013) is connected to a hydraulic pump 1 (1014).

3. The high-pressure air combustion ramming cracking coal rock experimental system according to claim 2 is characterized in that: The active and passive integrated sealed wire assembly (104) comprises a hole nut (1041) symmetrically arranged inside the fracturing device plugging cap (103), a copper rod (1042) passing through the middle of the hole nut (1041), and a sealing gasket (1043) arranged between the hole nut (1041) and the fracturing device plugging cap (103).

4. The high-pressure air combustion ramming cracking coal rock experimental system according to claim 3 is characterized in that: Copper rod sealing sections (10421) are provided at both ends of the copper rod (1042), and a winding groove (10422) is provided on the outer side of one end of the copper rod sealing section (10421); The outer side of the copper rod (1042) is coated with insulating paint and organic silicon high temperature resistant paint in sequence from the inside to the outside.

5. The high-pressure air combustion ramming cracking coal rock experimental system according to claim 3 is characterized in that: The interior of the fracturing device plugging cap (103) is provided with a thread (1031) that matches the hole-carrying nut (1041).

6. The high-pressure air combustion ramming cracking coal rock experimental system according to claim 2 is characterized in that: One end of the pressure relief slider (109) is provided with a chamfer, and the chamfer is set to 45 degrees.

7. The high-pressure air combustion ramming cracking coal rock experimental system according to claim 2 is characterized in that: The variable-size coal-rock true triaxial experimental device (2) comprises a rigid frame (201), and the cross section of the rigid frame (201) is a square structure, a plurality of hydraulic pumps (202) are arranged on the outside of the rigid frame (201), a plurality of hydraulic chambers (203) connected to the hydraulic pumps (202) are arranged inside the rigid frame (201), a plurality of pressure plates (204) are arranged in the middle of the hydraulic chamber (203), a pressure plate (205) is arranged on one side of the pressure plate (204), and a loading cylinder (206) is arranged on one side of the pressure plate (204) and in the middle of the pressure plate (205); A loading platen (207) is disposed on one side of the second pressure plate (205), and a sample (208) is disposed between the loading platens (207); A vent pipe drilling hole (209) connected to one of the air outlet ends of the vent pipe (3) is provided on a side wall of the rigid frame (201) away from one of the hydraulic pumps 2 (202).

8. The high-pressure air combustion ramming cracking coal rock experimental system according to claim 7 is characterized in that: The four corners of the loading plate (207) are provided with mounting holes (2071) for mounting an acoustic emission sensor and a potential sensor.

9. A method for using a high-pressure air combustion ramming cracking coal rock experimental system, for realizing the use of the high-pressure air combustion ramming cracking coal rock experimental system according to any one of claims 1 to 8, characterized in that: The method for using the high-pressure air combustion ramming cracking coal rock experimental system comprises the following steps: S1. Prepare to connect sensors and data acquisition equipment, and place rock samples in the true triaxial experimental device; S2, by selecting a suitable pressure plate and a loading cylinder to be activated according to the size of the coal and rock mass, applying confining pressure in the three-axis directions of X, Y, and Z through the loading cylinder (206); S3, pressurizing the pressure relief slider (109) to a set pressure value of 80 MPa through a hydraulic pump (1014), and inputting air into the energy-gathering agent cabin (101) through a gas pressurizing system (102), increasing the gas pressure in the energy-gathering agent cabin (101) to 30 MPa, and then closing the one-way valve (105); S4, connecting the wire pre-installed on the active and passive integrated sealed wire assembly (104) to an activator, and igniting the energy-gathering agent (108) through the activator, so that the fluid is heated and begins to undergo phase change; S5. When the fluid is heated so that the pressure in the energy-gathering agent cabin (101) reaches a predetermined value of 80 MPa, the pressure relief slider (109) is moved backward to relieve the pressure in the energy-gathering agent cabin (101), and the gas in the energy-gathering agent cabin (101) is released through the gas outlet (1010) and transported to the selected true triaxial test mechanism through the ventilation pipe (3), and data is collected using the temperature and pressure sensor at the gas outlet (1010); S6. The coal rock sample is cracked and damaged under the action of high temperature and high pressure gas, and pressure is applied to the pressure relief slider (109) through the hydraulic pump 1 (1014) to close the gas path, and the gas path connection at the gas outlet (1010) is released at the same time; S7, when the reaction in the energy-gathering agent chamber (101) is finished, the fracturing device plugging cap (103) is opened to discharge the waste residue, and after the waste residue is discharged, the pressure of the hydraulic pump 1 (1014) is released, and the pressure relief slider (109) is returned to its original position; S8. Clean the debris of coal and rock samples in the true triaxial test apparatus.

10. The method for using the high-pressure air combustion ramming cracking coal rock experimental system according to claim 9, characterized in that: The preparation for connecting the sensor and the data acquisition device and placing the rock sample in the true triaxial test device includes the following steps: S11, opening the fracturing device plugging cap (103), inputting the energy-gathering agent into the energy-gathering agent chamber (101) and connecting it to the excitation end, then screwing on the fracturing device plugging cap (103), installing and tightening the active and passive integrated sealed wire assembly (104); S12, connecting the temperature and pressure sensor 1 (107) and the temperature and pressure sensor 2 (1012) to a data acquisition device and a computer; S23. The rock sample with the middle hole processed is placed in the true triaxial experimental device by means of a loading and unloading trolley and a hydraulic crane, and the acoustic emission sensor and the potential sensor are installed on the surface of the rock sample through the installation borehole (2071).

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