An experimental device and method for electrochemical modification of soft rock based on ionic liquid

Abstract

The application discloses a kind of soft rock electrochemical modification experimental device based on ionic liquid, including water container, piston container and electrochemical modification jar, the piston container is arranged at one side of water container, and the piston container is composed of first upper cover, base, barrel and piston body, the electrochemical modification jar is arranged at one side of piston container, the electrochemical modification jar includes second upper cover and jar body, the inside of jar body is installed with soft rock sample, and the top end and bottom end of the soft rock sample are respectively installed with iron porous metal cathode and iron porous metal anode, plunger metering pump, pressure sensor, first stop valve, first pressure gauge are respectively arranged between water container and piston container.The application not only uses ionic liquid as electrolyte, effectively solves the problem of soft rock hydration disintegration in the process of soft rock electrochemical modification, but also realizes that electrolyte is pressurized and injected simultaneously with soft rock electrochemical modification.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soft rock electrochemical modification experiment, in particular to a soft rock electrochemical modification experiment device and method based on ionic liquid. BACKGROUND

[0002] In coal measures strata, the stability control of soft rock has always plagued the production and construction of coal mines. The engineering problem caused by soft rock is the result of continuous deterioration of rock mass quality under hydration or weathering. The basic theoretical research on the stability control of soft rock is a key scientific problem that needs to be solved urgently in the production and construction of coal mines. The methods for supporting and reinforcing soft rock in engineering include anchor shotcrete reinforcement, strong shed support, masonry or closed concrete arch, and various supporting methods produced by combining these methods, to ensure the stability and safety of the soft rock engineering. However, these methods are considered from the perspective of force balance, and do not consider improving the physical and chemical properties and mechanical properties of soft rock. Moreover, the engineering reinforced by the above methods often only maintains for a period of time and needs to be repaired frequently, and the repair engineering quantity, cost and impact on production are very large. Therefore, it is necessary to find a method to change the physical and chemical properties and mechanical properties of soft rock to achieve long-term stability of soft rock engineering.

[0003] Soft rock electrochemical modification is a technical method for changing the physical and chemical properties and mechanical properties of soft rock to achieve long-term stability of soft rock engineering. Soft rock electrochemical modification is to apply a low-voltage direct current electric field to soft rock. Under the action of the electric field, the exchangeable cations, small charged particles and polar water molecules in the rock mass migrate directionally, causing irreversible changes in the chemical properties of the rock mass, the double electric layer of minerals, the matrix and the pore and fracture structure, and further causing changes in the mechanical and engineering properties of the rock mass. Due to the low disturbance and effectiveness of this technical method on the rock mass, it has received increasing attention.

[0004] The principle of soft rock electrochemical modification is as follows:

[0005] The basic principle of electrochemical modification of soft rock is based on electrokinetic phenomena such as electroosmosis and electrophoresis. Electroosmosis causes more water molecules in the pores of soft rock to move towards the cathode. This is because, in the electrical double layer on the surface of clay mineral particles, the positively charged ions in the diffusion layer are replaced by positively charged ions in the electrolyte, carrying more water molecules towards the cathode. This reduces the hydration layer on the surface of the clay particles, decreases hydrophilicity, and causes dehydration and consolidation in the region near the anode. Intermolecular forces and hydrogen bonds increase, cohesion increases, and the clay minerals in the soft rock undergo crystallization. In soft rock, the clay mineral particles carry a negative charge. Under electrophoresis, these negatively charged clay mineral particles move towards the anode and accumulate, leading to the coarsening of fine particles in the pores and an increase in particle size. After electrochemical modification, the clay mineral content in the soft rock decreases, and new minerals are formed. Electrokinetic phenomena strengthen the bonding force between clay mineral particles in the soft rock, and cations form hydroxide precipitates on the surface of clay mineral particles in the pores, filling the pores and improving the mechanical properties of the soft rock.

[0006] Currently, existing technical solutions to this problem include traditional soft rock support and reinforcement methods such as anchor spraying reinforcement, high-strength arch support, masonry arches, and closed concrete arches. Most research focuses on reinforcing fractured or softened mudstone, addressing the issue primarily from a force balance perspective. This approach aims to control the stability of mudstone engineering by altering external factors, but it has significant limitations and time constraints. Electrochemical modification of soft rock can overcome the shortcomings of traditional methods, but existing methods use electrolytes such as NaCl, CaCl2, and CuCl2, which are salt solutions, while soft rock exhibits disintegration upon contact with water. Furthermore, electrochemical modification of soft rock requires a long timeframe, and the process presents a contradiction between the positive effects of electrochemical reinforcement and the negative effects of soft rock hydration and disintegration. Moreover, in existing electrochemical modification and reinforcement techniques for soft rock, the electrolyte is in contact with the soft rock at normal pressure. In reality, for electrochemical reinforcement of rock masses, the electrolyte must be injected under pressure. Therefore, we propose an experimental device for electrochemical modification of soft rock based on ionic liquids. Summary of the Invention

[0007] The purpose of this invention is to provide an experimental device for electrochemical modification of soft rock based on ionic liquids, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: an experimental device for electrochemical modification of soft rock based on ionic liquid, comprising a water container, a piston container, and an electrochemical modification tank. The piston container is disposed on one side of the water container and consists of a first upper cover, a base, a cylinder, and a piston body. The electrochemical modification tank is disposed on one side of the piston container and includes a second upper cover and a tank body. A soft rock sample is installed inside the tank body, and an iron perforated metal cathode and an iron perforated metal anode are respectively installed at the top and bottom of the soft rock sample. A plunger metering pump, a pressure sensor, a first shut-off valve, and a first pressure gauge are respectively disposed between the water container and the piston container. A regulated DC power supply, a third shut-off valve, and a second shut-off valve are disposed between the piston container and the electrochemical modification tank. A second pressure gauge, a fourth shut-off valve, a third pressure gauge, and a vacuum pump are respectively disposed on one side of the electrochemical modification tank.

[0009] Preferably, the water container is connected to a plunger metering pump via a pipeline.

[0010] Preferably, the plunger metering pump is connected in sequence with the pressure sensor, the first shut-off valve, and the first pressure gauge, and then connected to the first upper cover.

[0011] Preferably, the cylinder is connected to the first top cover and the base by threads, the piston body and the cylinder are in close sliding contact, and the base is connected to the tank body through a pipeline via a third shut-off valve.

[0012] Preferably, the soft rock sample is tightly bonded to the ferrous perforated metal anode and the ferrous perforated metal cathode. The tank body is connected to the second top cover by threads. The second top cover is connected to the second pressure gauge, the fourth shut-off valve, and the third pressure gauge in sequence via pipelines, and then connected to the vacuum pump.

[0013] Preferably, the regulated DC power supply is connected to the perforated iron anode and the perforated iron cathode via wires to provide electrical energy to the soft rock specimen.

[0014] Preferably, the pressure sensor, the first pressure gauge, the second pressure gauge, the third pressure gauge, the fourth shut-off valve, and the vacuum pump constitute a pressure control and monitoring system for controlling and monitoring the pressure of the experimental system.

[0015] Preferably, the can body is made of a transparent insulating material.

[0016] An experimental method for electrochemical modification of soft rock based on ionic liquids is proposed. The first step involves drilling a 5mm diameter and 5mm deep hole at the center of the bottom of a 50×100mm standard cylindrical soft rock sample. The second step involves placing the sample in an electrochemical modification vessel, inserting an electrolyte injection tube into the hole at the center of the bottom of the sample, installing a perforated iron anode and cathode, connecting wires, sealing the electrochemical modification vessel, connecting a fourth shut-off valve, a third pressure gauge, and a vacuum pump, closing the valve between the electrochemical modification vessel and the piston container, adding electrolyte to the piston container, sealing the piston container, connecting a first pressure gauge, a first shut-off valve, a pressure sensor, and a plunger metering pump, opening the fourth shut-off valve, and starting the vacuum pump to perform electrochemical modification. The process involves: 1) Vacuuming the cylindrical soft rock sample tank; 2) After vacuuming, closing the fourth shut-off valve and opening the first and third shut-off valves, then starting the plunger metering pump to inject electrolyte into the sample; 3) Applying a DC voltage to the sample and starting the simultaneous pressurized injection and electrochemical modification experiment; 4) Stopping the pressurized injection operation when the electrolyte level reaches 5mm from the top of the sample, and continuing to maintain the energized state for 72 hours; 5) After the experiment, closing the first and third shut-off valves, opening the second shut-off valve on the electrolyte discharge line at the bottom of the tank to drain the electrolyte, removing the sample, vacuum drying it, and then performing a Brazilian splitting test on the specimen using a universal testing machine to calculate the tensile strength.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] This invention employs ionic liquids as the electrolyte, effectively solving the problem of soft rock hydration and disintegration during the electrochemical modification of soft rock. Addressing the defect of water in salt solutions causing softening and disintegration of soft rock during electrochemical modification, this invention utilizes ionic liquids as the electrolyte, effectively resolving this issue. Ionic liquids possess advantages such as low vapor pressure, high conductivity, high electrochemical stability, and strong designability, fully meeting the requirements for electrolytes in electrochemical modification. Furthermore, when used as the electrolyte for electrochemical modification, the ionic liquid directly contacts the electrode, resulting in low impedance and good diffusion and flowability of active substances and additives. Ionic liquids are liquids composed entirely of ions, are liquid salts at low temperatures (<100℃), and contain no water, thus avoiding the water absorption, swelling, softening, and disintegration characteristics of soft rock, leading to a more significant electrochemical modification effect. This invention develops an experimental device for in-situ electrochemical modification of soft rock, enabling simultaneous pressurized electrolyte injection and electrochemical modification of soft rock. To address the shortcomings of existing electrochemical modification and reinforcement techniques for soft rock involving non-pressurized electrolyte injection, this invention develops an experimental apparatus for the coordinated implementation of pressurized electrolyte injection and electrochemical modification of soft rock. This apparatus integrates pressurized injection with electrochemical modification, thus improving the technical method for soft rock electrochemical modification. In summary, this invention effectively solves the problem of soft rock hydration and disintegration during conventional soft rock electrochemical modification using salt solutions as electrolytes. The in-situ electrochemical modification apparatus for soft rock involved in this invention enables the coordinated implementation of pressurized electrolyte injection and electrochemical modification, making it more closely aligned with engineering practice. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 This is an enlarged schematic diagram of the piston container structure of the present invention;

[0021] Figure 3 This is an enlarged structural schematic diagram of the electrochemical modification tank of the present invention;

[0022] Figure 4 This is a schematic diagram of the piston container pressure control and monitoring system of the present invention;

[0023] Figure 5 This is a schematic diagram of the electrochemical modification tank pressure control and monitoring system of the present invention.

[0024] In the diagram: 1. Water container; 2. Plunger metering pump; 3. Pressure sensor; 4. First shut-off valve; 5. First pressure gauge; 6. First top cover; 7. Cylinder; 8. Piston body; 9. Base; 10. Second shut-off valve; 11. Third shut-off valve; 12. Regulated DC power supply; 13. Second pressure gauge; 14. Porous iron anode; 15. Soft rock sample; 16. Tank body; 17. Porous iron cathode; 18. Second top cover; 19. Fourth shut-off valve; 20. Third pressure gauge; 21. Vacuum pump; 22. Piston container; 23. Electrochemical modification tank. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Please see Figures 1-5 An embodiment of the present invention provides an experimental device for electrochemical modification of soft rock based on ionic liquid, comprising a water container 1, a piston container 22, and an electrochemical modification tank 23. The piston container 22 is disposed on one side of the water container 1 and is composed of a first upper cover 6, a base 9, a cylinder 7, and a piston body 8. The electrochemical modification tank 23 is disposed on one side of the piston container 22 and includes a second upper cover 18 and a tank body 16. A soft rock sample 15 is installed inside the tank body 16, and an iron perforated metal cathode 17 and an iron perforated metal anode 14 are respectively installed at the top and bottom of the soft rock sample 15.

[0028] A plunger metering pump 2, a pressure sensor 3, a first shut-off valve 4, and a first pressure gauge 5 are respectively installed between the water container 1 and the piston container 22;

[0029] A regulated DC power supply 12, a third shut-off valve 11, and a second shut-off valve 10 are provided between the piston container 22 and the electrochemical modification tank 23;

[0030] A second pressure gauge 13, a fourth shut-off valve 19, a third pressure gauge 20, and a vacuum pump 21 are respectively installed on one side of the electrochemical modification tank 23;

[0031] Water container 1 is connected to plunger metering pump 2 via pipeline;

[0032] The plunger metering pump 2 is connected in sequence with the pressure sensor 3, the first shut-off valve 4, and the first pressure gauge 5, and then connected to the first upper cover 6.

[0033] The cylinder 7 is connected to the first upper cover 6 and the base 9 by threads. The piston body 8 and the cylinder 7 are in close sliding contact. The base 9 is connected to the tank body 16 through a pipeline via the third shut-off valve 11.

[0034] The soft rock sample 15 is tightly attached to the iron perforated metal anode 14 and the iron perforated metal cathode 17. The tank body 16 is connected to the second upper cover 18 by threads. The second upper cover 18 is connected to the second pressure gauge 13, the fourth shut-off valve 19 and the third pressure gauge 20 in sequence through pipelines and then connected to the vacuum pump 21.

[0035] The regulated DC power supply 12 is connected to the perforated iron metal anode 14 and the perforated iron metal cathode 17 via wires.

[0036] Pressure sensor 3, first pressure gauge 5, second pressure gauge 13, third pressure gauge 20, fourth shut-off valve 19, and vacuum pump 21 constitute a pressure control and monitoring system for controlling and monitoring the pressure of the experimental system.

[0037] The can body 16 is made of transparent insulating material;

[0038] Specifically, the integrated experimental method of pressurized injection and electrochemical modification of soft rock is as follows: A hole with a diameter and depth of 5 mm is drilled at the center of the bottom end of a 50×100 mm standard cylindrical soft rock sample 15. The sample is then placed in the electrochemical modification tank 23. The electrolyte injection tube is placed in the hole at the center of the bottom end of the soft rock sample 15. A perforated iron anode 14 and a perforated iron cathode 17 are installed and connected with wires. The electrochemical modification tank 23 is sealed. The fourth shut-off valve 19, the third pressure gauge 20, and the vacuum pump 21 are connected. The valve between the electrochemical modification tank 23 and the piston container 22 is closed. Electrolyte is added to the piston container 22. In the process, the sealed piston container 22 is connected with the first pressure gauge 5, the first shut-off valve 4, the pressure sensor 3, and the plunger metering pump 2. The fourth shut-off valve 19 is opened, and the vacuum pump 21 is turned on to evacuate the electrochemical modification tank. After the evacuation is completed, the fourth shut-off valve 19 is closed, the first shut-off valve 4 and the third shut-off valve 11 are opened, and the plunger metering pump 2 is turned on to inject electrolyte into the cylindrical soft rock sample 15. At the same time, a DC voltage is applied to the cylindrical soft rock sample 15 to start the synchronous experiment of pressurized injection and soft rock electrochemical modification. When the electrolyte rises to 5 mm from the top of the soft rock sample 15, the pressurized injection operation is stopped, and the energized state is maintained for 72 hours.

[0039] After the experiment, close the first shut-off valve 4 and the third shut-off valve 11, open the second shut-off valve 10 on the electrolyte discharge pipeline at the bottom of the electrochemical modification tank 23, drain the electrolyte in the electrochemical modification tank 23, take out the cylindrical soft rock sample 15, vacuum dry it, and then use a universal testing machine to conduct a Brazilian splitting test on the sample to calculate the tensile strength.

[0040] This invention employs ionic liquids as the electrolyte, effectively solving the problem of soft rock hydration and disintegration during the electrochemical modification of soft rock. Addressing the defect of water in salt solutions causing softening and disintegration of soft rock during electrochemical modification, this invention utilizes ionic liquids as the electrolyte, effectively resolving this issue. Ionic liquids possess advantages such as low vapor pressure, high conductivity, high electrochemical stability, and strong designability, fully meeting the requirements for electrolytes in electrochemical modification. Furthermore, when used as the electrolyte for electrochemical modification, the ionic liquid directly contacts the electrode, resulting in low impedance and good diffusion and flowability of active substances and additives. Ionic liquids are liquids composed entirely of ions, are liquid salts at low temperatures (<100℃), and contain no water, thus avoiding the water absorption, swelling, softening, and disintegration characteristics of soft rock, leading to a more significant electrochemical modification effect. This invention develops an experimental device for in-situ electrochemical modification of soft rock, enabling simultaneous pressurized electrolyte injection and electrochemical modification of soft rock. To address the shortcomings of existing electrochemical modification and reinforcement techniques for soft rock, which involve non-pressurized injection of electrolyte into the soft rock mass, this invention achieves integrated pressurized injection and electrochemical modification of soft rock, thus improving the technical method for electrochemical modification of soft rock. In summary, this invention effectively solves the problem of soft rock hydration and disintegration during conventional electrochemical modification using salt solutions as electrolytes. The experimental apparatus for in-situ electrochemical modification of soft rock involved in this invention enables the coordinated execution of pressurized electrolyte injection and electrochemical modification of soft rock, making it more closely aligned with engineering practice.

[0041] Soft rock modification effect

[0042] Implementation Plan 1: Using a 1 mol / L imidazole ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate aqueous solution, as the electrolyte, pressurized injection and electrochemical modification of soft rock were carried out simultaneously under injection pressure of 0.15 MPa and a potential gradient of 1.0 V / cm. After electrochemical modification and vacuum drying, the specimens were subjected to Brazilian splitting tests using a universal testing machine. The load-displacement curves of the specimens were obtained, and the tensile strength of the specimens was calculated to be 3.82 MPa, which is 5.82% higher than the tensile strength of the original soft rock specimen before modification (3.61 MPa).

[0043] Implementation Plan 2: Using a 1 mol / L imidazole ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate aqueous solution, as the electrolyte, pressurized injection and electrochemical modification of soft rock were carried out simultaneously under injection pressure of 0.15 MPa and a potential gradient of 1.0 V / cm. After electrochemical modification and vacuum drying, Brazilian splitting tests were performed on the specimens using a universal testing machine to obtain the load-displacement curves. The calculated tensile strength of the specimen was 3.91 MPa, which is 8.31% higher than the tensile strength of the original soft rock specimen before modification (3.61 MPa).

[0044] Implementation Plan 3: Using a 1.5 mol / L imidazole ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate aqueous solution, as the electrolyte, pressurized injection and electrochemical modification of soft rock were carried out simultaneously under injection pressure of 0.15 MPa and a potential gradient of 1.0 V / cm. After electrochemical modification and vacuum drying, Brazilian splitting tests were performed on the specimens using a universal testing machine to obtain the load-displacement curves. The calculated tensile strength of the specimen was 3.99 MPa, which is 10.53% higher than the tensile strength of the original soft rock specimen before modification (3.61 MPa).

[0045] Implementation Plan 4: Using a 0.5 mol / L imidazole-based ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate aqueous solution, as the electrolyte, pressurized injection and electrochemical modification of soft rock were carried out simultaneously under injection pressure of 0.15 MPa and a potential gradient of 1.0 V / cm. After electrochemical modification and vacuum drying, the specimens were subjected to Brazilian splitting tests using a universal testing machine. The load-displacement curves of the specimens were obtained, and the calculated tensile strength of the specimens was 3.74 MPa, which is 3.60% higher than the tensile strength of the original soft rock specimens before modification (3.61 MPa).

[0046] Implementation Plan 5: Using a 1.5 mol / L CuCl2 aqueous solution as the electrolyte, pressurized injection and electrochemical modification of soft rock were carried out simultaneously under injection pressure of 0.15 MPa and a potential gradient of 1.0 V / cm. After electrochemical modification and vacuum drying, Brazilian splitting tests were conducted on the specimens using a universal testing machine to obtain the load-displacement curves. The calculated tensile strength of the specimen was 3.37 MPa, which was 6.65% lower than the tensile strength of the original soft rock specimen before modification (3.61 MPa).

[0047] Implementation Plan Six: Using pure imidazole-based ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate as the electrolyte, pressurized injection and electrochemical modification of soft rock were carried out simultaneously under the conditions of injection pressure of 0.15 MPa and potential gradient of 1.0 V / cm. After electrochemical modification and vacuum drying, the specimens were subjected to Brazilian splitting tests using a universal testing machine to obtain the load-displacement curves. The calculated tensile strength of the specimens was 4.56 MPa, which is 26.32% higher than the tensile strength of the original soft rock specimens before modification (3.61 MPa); and 35.31% higher than the tensile strength of the soft rock specimens after electrochemical modification in 1.5 mol / L CuCl2 aqueous solution (3.37 MPa).

[0048] Implementation Plan Seven: Using pure imidazole-based ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate as the electrolyte, pressurized injection and electrochemical modification of soft rock were carried out simultaneously under the conditions of injection pressure of 0.15 MPa and potential gradient of 1.0 V / cm. After completing the electrochemical modification and vacuum drying, the specimens were subjected to Brazilian splitting tests using a universal testing machine. The load-displacement curves of the specimens were obtained. The calculated tensile strength of the specimens was 4.69 MPa, which is 29.92% higher than the tensile strength of the original soft rock specimens before modification (3.61 MPa); and 39.17% higher than the tensile strength of the soft rock specimens after electrochemical modification in 1.5 mol / L CuCl2 aqueous solution (3.37 MPa).

[0049] In use, the following is a description of the device: First, the device mainly consists of an injection system, an electrochemical modification system, and a pressure control and monitoring system. The injection system for injecting electrolyte into soft rock samples includes a water container 1 for holding the water medium providing injection pressure, a plunger metering pump 2, a first shut-off valve 4, a third shut-off valve 11 for providing injection pressure, and a piston container 22 for holding the electrolyte. The piston container 22 consists of a first upper cover 6, a base 9, a cylinder 7, and a piston body 8. The electrochemical modification system for electrochemical modification of soft rock includes a soft rock sample 15, an electrochemical modification tank 23 (a second upper cover 18 and a tank body 16), a regulated DC power supply 12 for providing electrical energy to the soft rock sample, a perforated iron metal anode 14, a perforated iron metal cathode 17, and a second shut-off valve 10 for discharging the electrolyte. The pressure control and monitoring system includes a pressure sensor 3, a first pressure gauge 5, a second pressure gauge 13, a third pressure gauge 20, a fourth shut-off valve 19, and a vacuum pump 21. The connection method is as follows: the water container 1 is connected to the plunger metering pump 2 through a pipeline. The plunger metering pump 2 is connected to the pressure sensor 3, the first shut-off valve 4, and the first pressure gauge 5 in sequence, and then connected to the piston container 22 through the first upper cover 6. The cylinder 7 is connected to the first upper cover 6 and the base 9 through a threaded connection. The piston body 8 and the cylinder 7 are in close sliding contact. The base 9 is connected to the tank body 16 through a pipeline via the third shut-off valve 11. The regulated DC power supply 12 is connected to the iron perforated metal anode 14 and the iron perforated metal cathode 17 through a wire. The soft rock sample 15 is placed at the bottom of the tank body 16 after being tightly attached to the iron perforated metal anode 14 and the iron perforated metal cathode 17. The tank body 16 is connected to the second upper cover 18 through a threaded connection. The second upper cover 18 is connected to the second pressure gauge 13, the fourth shut-off valve 19, and the third pressure gauge 20 in sequence through a pipeline, and then connected to the vacuum pump 21.

[0050] The integrated experimental method for pressurized injection and electrochemical modification of soft rock is as follows: A hole with a diameter and depth of 5 mm is drilled at the center of the bottom end of a 50×100 mm standard cylindrical soft rock sample 15. The sample is then placed in an electrochemical modification tank 23. The electrolyte injection tube is placed in the hole at the center of the bottom end of the soft rock sample 15. An iron perforated metal anode 14 and an iron perforated metal cathode 17 are installed and connected with wires. The electrochemical modification tank 23 is sealed. The fourth shut-off valve 19, the third pressure gauge 20, and the vacuum pump 21 are connected. The valve between the electrochemical modification tank 23 and the piston container 22 is closed. Electrolyte is then added to the piston container 22. Seal the piston container 22, connect the first pressure gauge 5, the first shut-off valve 4, the pressure sensor 3, and the plunger metering pump 2, open the fourth shut-off valve 19, and start the vacuum pump 21 to evacuate the electrochemical modification tank. After evacuation, close the fourth shut-off valve 19, open the first shut-off valve 4 and the third shut-off valve 11, and start the plunger metering pump 2 to inject electrolyte into the cylindrical soft rock sample 15. At the same time, apply a DC voltage to the cylindrical soft rock sample 15 to start the pressurized injection and soft rock electrochemical modification synchronous experiment. When the electrolyte rises to 5 mm from the top of the soft rock sample 15, stop the pressurized injection operation and continue to maintain the energized state for 72 hours. After the experiment, close the first shut-off valve 4 and the third shut-off valve 11, open the second shut-off valve 10 on the electrolyte discharge pipeline at the bottom of the electrochemical modification tank 23 to discharge the electrolyte in the electrochemical modification tank 23, and then take out the cylindrical soft rock sample 15. After vacuum drying, use a universal testing machine to perform a Brazilian splitting test on the specimen and calculate the tensile strength.

[0051] This invention employs ionic liquids as the electrolyte, effectively solving the problem of soft rock hydration and disintegration during the electrochemical modification of soft rock. Addressing the defect of water in salt solutions causing softening and disintegration of soft rock during electrochemical modification, this invention utilizes ionic liquids as the electrolyte, effectively resolving this issue. Ionic liquids possess advantages such as low vapor pressure, high conductivity, high electrochemical stability, and strong designability, fully meeting the requirements for electrolytes in electrochemical modification. Furthermore, when used as the electrolyte for electrochemical modification, the ionic liquid directly contacts the electrode, resulting in low impedance and good diffusion and flowability of active substances and additives. Ionic liquids are liquids composed entirely of ions, are liquid salts at low temperatures (<100℃), and contain no water, thus avoiding the water absorption, swelling, softening, and disintegration characteristics of soft rock, leading to a more significant electrochemical modification effect. This invention develops an experimental device for in-situ electrochemical modification of soft rock, enabling simultaneous pressurized electrolyte injection and electrochemical modification of soft rock. To address the shortcomings of existing electrochemical modification and reinforcement techniques for soft rock, which involve non-pressurized injection of electrolyte into the soft rock mass, this invention achieves integrated pressurized injection and electrochemical modification of soft rock, thus improving the technical method for electrochemical modification of soft rock. In summary, this invention effectively solves the problem of soft rock hydration and disintegration during conventional electrochemical modification using salt solutions as electrolytes. The experimental apparatus for in-situ electrochemical modification of soft rock involved in this invention enables the coordinated execution of pressurized electrolyte injection and electrochemical modification of soft rock, making it more closely aligned with engineering practice.

[0052] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. An experimental method for electrochemical modification of soft rock based on ionic liquids, applied to an experimental apparatus for electrochemical modification of soft rock based on ionic liquids, characterized in that, The experimental apparatus for electrochemical modification of soft rock based on ionic liquid includes a water container (1), a piston container (22), and an electrochemical modification tank (23). The piston container (22) is located on one side of the water container (1) and consists of a first top cover (6), a base (9), a cylinder (7), and a piston body (8). The electrochemical modification tank (23) is located on one side of the piston container (22) and includes a second top cover (18) and a tank body (16). A soft rock sample (15) is installed inside the tank body (16), and the top of the soft rock sample (15) is... Iron perforated metal cathode (17) and iron perforated metal anode (14) are respectively installed at the bottom and the water container (1). A plunger metering pump (2), a pressure sensor (3), a first shut-off valve (4), and a first pressure gauge (5) are respectively installed between the water container (1) and the piston container (22). A regulated DC power supply (12), a third shut-off valve (11), and a second shut-off valve (10) are installed between the piston container (22) and the electrochemical modification tank (23). A second pressure gauge (13), a fourth shut-off valve (19), a third pressure gauge (20), and a vacuum pump (21) are respectively installed on one side of the electrochemical modification tank (23). The plunger metering pump (2) is connected in sequence with the pressure sensor (3), the first shut-off valve (4), and the first pressure gauge (5) and then connected to the first upper cover (6); The cylinder (7) is connected to the first upper cover (6) and the base (9) by threads. The piston body (8) and the cylinder (7) are in close sliding contact. The base (9) is connected to the tank (16) through a pipeline via the third shut-off valve (11). The soft rock sample (15) is closely attached to the iron porous metal anode (14) and the iron porous metal cathode (17). The tank body (16) is connected to the second upper cover (18) by threads. The second upper cover (18) is connected to the second pressure gauge (13), the fourth shut-off valve (19), and the third pressure gauge (20) in sequence through pipelines and then connected to the vacuum pump (21). The regulated DC power supply (12) is connected to the perforated iron metal anode (14) and the perforated iron metal cathode (17) via wires; The experimental method for electrochemical modification of soft rock based on ionic liquid includes the following steps: First, drill a hole with a diameter and depth of 5 mm at the center of the bottom end of a 50×100 mm standard cylindrical soft rock sample (15); Second, place it in an electrochemical modification tank (23), place the electrolyte injection tube in the hole at the center of the bottom end of the soft rock sample (15), install the iron perforated metal anode (14) and iron perforated metal cathode (17), connect the wires, seal the electrochemical modification tank (23), connect the fourth shut-off valve (19), the third pressure gauge (20) and the vacuum pump (21), close the valve between the electrochemical modification tank (23) and the piston container (22), add the electrolyte to the piston container (22), seal the piston container (22), connect the first pressure gauge (5), the first shut-off valve (4), the pressure sensor (3), and the plunger metering pump (2), and open the fourth shut-off valve (19). First, turn on the vacuum pump (21) to evacuate the electrochemical modification tank; second, after evacuation, close the fourth shut-off valve (19), open the first shut-off valve (4) and the third shut-off valve (11), and turn on the plunger metering pump (2) to inject electrolyte into the cylindrical soft rock sample (15); third, apply DC voltage to the cylindrical soft rock sample (15) and start the pressurized injection and soft rock electrochemical modification synchronous experiment. When the electrolyte rises to 5 mm from the top of the soft rock sample (15), stop the pressurized injection operation and continue to maintain the energized state for 72 hours; fourth, after the experiment, close the first shut-off valve (4) and the third shut-off valve (11), open the second shut-off valve (10) on the electrolyte discharge pipeline at the bottom of the electrochemical modification tank (23) to discharge the electrolyte in the electrochemical modification tank (23), and then take out the cylindrical soft rock sample (15). After vacuum drying, use a universal testing machine to perform a Brazilian splitting test on the specimen and calculate the tensile strength.

2. The experimental method for electrochemical modification of soft rock based on ionic liquids according to claim 1, characterized in that: The water container (1) is connected to the plunger metering pump (2) via a pipeline.

3. The experimental method for electrochemical modification of soft rock based on ionic liquids according to claim 1, characterized in that: The pressure sensor (3), the first pressure gauge (5), the second pressure gauge (13), the third pressure gauge (20), the fourth shut-off valve (19), and the vacuum pump (21) constitute a pressure control and monitoring system for controlling and monitoring the pressure of the experimental system.

4. The experimental method for electrochemical modification of soft rock based on ionic liquids according to claim 1, characterized in that: The tank (16) is made of a transparent insulating material.

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