Fracture self-healing test equipment and method under high confining pressure-shear-seepage coupling conditions

Abstract

This invention relates to a test apparatus and method for fracture self-healing under high confining pressure-shear-seepage coupling conditions. The apparatus includes: a high-precision constant flow pump, a rock sample holder, a confining pressure pump, an axial pressure pump, a self-healing material injection system, a flow meter, and an integrated measurement and control system. The rock sample holder is used to hold standard samples. The high-precision constant flow pump is connected to the seepage inlet interface of the rock sample holder through a high-pressure resistant pipeline for injecting fluid or self-healing material into the sample. The confining pressure pump and the axial pressure pump are respectively connected to the confining pressure interface and the axial pressure interface of the rock sample holder through pipelines. The self-healing material injection system is connected to the high-precision constant flow pump and / or the seepage inlet interface of the rock sample holder for injecting self-healing material into fractures subjected to shear disturbance. Compared with the prior art, this invention achieves realistic and dynamic multi-field coupling simulation, ensuring the accuracy of data and the reliability of the system under high-pressure dynamic environment, and has the capability to study the entire process of fracture self-healing under real stress paths.

Description

Technical Field

[0001] This invention relates to the field of rock mechanics, and in particular to experimental equipment and methods for self-healing fractures under high confining pressure-shear-seepage coupling conditions. Background Technology

[0002] As underground space development continues to extend deeper, underground engineering structures such as tunnel linings, chamber surrounding rock, and energy storage facilities are subjected to multiple complex stress environments, including high ground stress, high seepage pressure, and disturbances induced by engineering activities. Under these conditions, the initiation, propagation, and even penetrating failure of fissures within the rock mass have become decisive factors restricting the long-term stability and service safety of the structures.

[0003] Currently, most experimental devices for studying fractures focus on a single mechanical environment, failing to simulate coupled stress fields and neglecting the testing of self-healing materials for fractures. Existing similar patents include: "Monitoring-type Rock Mass Seepage Meter and Seepage Experiment Method" (2023): This patent fixes the test specimen inside a clamping sleeve and performs a seepage test on the specimen, allowing for image monitoring of the seepage test process based on a monitoring frame. "Rock Shear Test System and Method under Complex Compression-Torsion Stress Coupling" (2023): This patent applies a constant axial pressure to the rock specimen by driving an axial pressure loading component to slide inward along the axial pressure loading channel, measuring the deformation and damage of the rock specimen during the test, and collecting information for data analysis. "A Self-Healing Energetic Adhesive and its Preparation Method" (2025): This patent belongs to the field of polymer materials. The adhesive, composed of anionic copolymer emulsion and cationic copolymer emulsion, works synergistically, giving the PBX prepared by this adhesive system a certain degree of self-healing property and extending the material's service life.

[0004] The shortcomings of existing patents are: the equipment functions are relatively limited, making it difficult to achieve simultaneous control and precise coupling of high confining pressure, shear load, and high water pressure on the same sample; the environmental conditions differ significantly from the high confining pressure conditions of deep underground engineering; the applicability of the test results is limited; and there are few devices that focus on testing the performance of self-healing materials for fractures. It is difficult to realistically simulate and study the self-healing mechanism of fractures under multi-field coupling in deep geological environments, nor can it reliably evaluate the sealing effectiveness of self-healing materials in such complex environments. Therefore, there is an urgent need for a comprehensive experimental device that can integrate multi-field coupling and self-healing testing under real stress. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the existing technology and provide a test device and method for crack self-healing under high confining pressure-shear-seepage coupling conditions. It realizes real and dynamic multi-field coupling simulation, ensures the accuracy of data and the reliability of the system under high pressure dynamic environment, and has the ability to study the whole process of crack self-healing under real stress path.

[0006] The objective of this invention can be achieved through the following technical solutions: This invention provides a test device for crack self-healing under high confining pressure-shear-seepage coupling conditions, comprising: a high-precision constant flow pump, a rock sample holder, a confining pressure pump, an axial pressure pump, a self-healing material injection system, a flow meter, and an integrated measurement and control system; The rock sample holder is used to hold standard samples and is equipped with a confining pressure interface, an axial pressure interface, a seepage inlet interface, and a seepage outlet interface. The cylinder of the rock sample holder is made of high-strength stainless steel alloy. It can hold Φ50×100 mm standard samples and can withstand confining pressure and axial pressure up to 30 MPa, with an accuracy of 0.1% FS. The high-precision constant flow pump is connected to the seepage inlet interface of the rock sample holder through a high-pressure resistant pipeline. It is used to inject fluid or self-healing material into the sample. The flow rate range is 0.1-100 ml / min and the maximum working pressure is 20 MPa. The confining pressure pump and axial pressure pump are respectively connected to the confining pressure interface and axial pressure interface of the rock sample holder through pipelines, and are used to apply independent confining pressure and axial stress to the sample. The maximum working pressure of the confining pressure pump and the axial pressure pump is 30 MPa. The maximum working pressure of the confining pressure pump is 30 MPa, and the pressure resistance is up to 70 MPa. It is used to apply uniform pressure constraint to the sample. The axial pressure pump has a range of 0-30 MPa and an accuracy of 0.1% FS. It is used to apply stable and adjustable shear displacement to the sample.

[0007] The self-healing material injection system is connected to the seepage inlet interface of the high-precision constant flow pump and / or the rock sample holder, and is used to inject self-healing material into the fractures that have been sheared and disturbed; the self-healing material in the self-healing material injection system is disposed in the self-healing material cavity; The flow meter includes a high-precision electronic balance connected to the seepage outlet interface of the rock sample holder, used to measure the mass of the seepage fluid in real time, with a scale division of 0.01 g and a measuring range of 2200 g; The integrated measurement and control system is electrically connected to the high-precision constant flow pump, confining pressure pump, axial pressure pump, sensors on the rock sample holder, and flow meter. It is used to control each loading unit and collect and process test data, realizing integrated and automated control of the entire process from sample saturation, stress loading, shear-seepage coupling, self-healing material injection to healing effect testing.

[0008] Furthermore, the rock sample holder also includes a rubber sleeve, a tapered sleeve, a pressure cap, a plug, and a sealing device. Through the combination of the rubber sleeve, tapered sleeve, pressure cap, plug, and sealing device, a reliable seal between the confining pressure medium and the pore fluid is achieved under high pressure and shear displacement.

[0009] Furthermore, it also includes an intermediate pressure vessel, which is a piston-type pressure vessel installed on the pipeline between the high-precision constant flow pump and the rock sample holder. It is equipped with an isolation piston inside to isolate the power fluid from the working medium and buffer pressure fluctuations. The maximum working pressure is 30MPa and the volume is 1000ml.

[0010] Furthermore, the high-precision constant flow pump employs microcomputer control and stepper motor control, with the pump body and control system being independent units; it achieves precise and stable flow rate control (0.1-100 ml / min), a maximum pore pressure of 20 MPa, and an accuracy of 0.1% FS. It utilizes a dual-cam drive mechanism, with two pump heads working alternately, resulting in stable output flow and minimal pressure fluctuations.

[0011] Furthermore, both the confining pressure pump and the axial pressure pump are high-precision manual pumps with stroke locking function and built-in safety valves.

[0012] Furthermore, it also includes a vacuum system, which includes a vacuum pump, a vacuum gauge, and valve lines, used to evacuate and degas the sample and fluid lines before the test.

[0013] Furthermore, the vacuum system also includes interconnected buffer tubes and a dryer.

[0014] The vacuum pump is a 2XZ-4 type vacuum pump and the buffer tube is a ZR-5 type vacuum buffer container.

[0015] Furthermore, the sensors on the rock sample holder include pressure sensors and displacement sensors.

[0016] This invention also provides a test method for crack self-healing under high confining pressure-shear-seepage coupling conditions, comprising the following steps: S1. Stress loading and sample saturation: The sample is loaded into the rock sample holder, and the confining pressure and axial pressure are applied to the target value and kept stable by the confining pressure pump and axial pressure pump to simulate the in-situ stress state underground; then the sample is evacuated and fluid is injected to complete the sample saturation. S2. Benchmark seepage test: Under the set stress, start a high-precision constant flow pump to inject fluid into the sample at a constant flow rate. After the flow stabilizes, calculate the initial permeability of the fracture by recording the stable flow rate and inlet pressure through a flow meter. S3. Shear-flow coupling test: Under the conditions of maintaining confining pressure, axial pressure and constant seepage, shear displacement is applied to the sample through an axial pressure pump, and the changes in shear force, shear displacement, pore pressure and real-time seepage flow are monitored and recorded simultaneously. S4. Self-healing material injection and self-healing process simulation: After shearing is completed or a specific shear displacement is reached, switch to the self-healing material injection system, inject self-healing material into the crack, and then carry out curing under stable confining pressure. S5. Healing effect test: After the curing is completed, under the same stress and boundary conditions as in step S3, a seepage test is conducted again. By comparing the changes in crack permeability before and after self-healing, the sealing effect of the self-healing material is quantitatively evaluated.

[0017] S6. Results Output: Throughout the experiment, this platform automatically collects all sensor data and processes it in real time; it can eventually automatically generate a comprehensive test report containing shear stress-displacement curves, permeability-shear displacement evolution curves, and injection pressure-time curves, providing complete data analysis for analyzing the mechanical-seepage behavior and self-healing efficiency of fractures under coupling effects.

[0018] Furthermore, in step S1, the target values ​​of the confining pressure and axial pressure can reach up to 30 MPa; The high-precision constant flow pump provides a seepage flow rate range of 0.1-100 ml / min in steps S2 and S5.

[0019] Compared with the prior art, the present invention has the following advantages: (1) Realistic and dynamic multi-field coupling simulation is achieved: Existing equipment has a single function, making it difficult to achieve synchronous control and precise coupling of high confining pressure, shear load and high water pressure on the same sample, and cannot realistically simulate the complex environment of multi-field coupling in deep underground engineering. This invention integrates multiple functional modules such as confining pressure, axial pressure, shear loading and high-pressure seepage injection into the same equipment through integrated design, and realizes precise linkage between the modules. This enables the equipment to support the test under high confining pressure constraint and real shear displacement for the first time, accurately simulate the real coupling process of dynamic interaction between high confining pressure, shear and seepage, break through the limitation of traditional equipment that can only perform single-factor tests, and significantly improve the engineering applicability of the test results.

[0020] (2) Ensuring the accuracy of data and the reliability of the system under high-pressure dynamic conditions: Traditional equipment is prone to sealing failure under high-pressure and shear displacement coupled conditions, leading to fluid leakage and pressure instability, and the accuracy of data acquisition is limited. This invention adopts a series of high-precision core components, such as a high-precision constant flow pump (flow accuracy 0.01 ml / min, pressure accuracy 0.1%FS), a high-precision manual pump (accuracy 0.1%FS), and an electronic balance with a 0.01g graduation value, to ensure the accurate acquisition of key mechanical and seepage data such as stress, displacement, pressure, and flow rate. A multi-layered collaborative dynamic sealing structure is adopted to ensure long-term effective sealing of the sample under high pressure (up to 30MPa) and shear displacement, solving the leakage problem in traditional tests. At the same time, the isolation piston of the intermediate pressure vessel is used to transmit power, realizing the stable transmission of pressure.

[0021] (3) Capable of studying the entire process of crack self-healing under real stress paths: Existing equipment rarely focuses on the performance testing of crack self-healing materials, and cannot reliably evaluate the sealing effectiveness of self-healing materials under real engineering stress environments. This invention integrates a set of grouting self-healing and effectiveness testing equipment on a high-pressure seepage simulation platform. This enables researchers to complete the entire process of crack grouting, material curing, and healing effect testing for the first time under stress environments that maintain high confining pressure and real shear displacement coupling. It can quantitatively study the diffusion law and solidification strength of grout in shear cracks, and compare the changes in crack permeability before and after self-healing, thereby leaping the research on self-healing materials from atmospheric pressure environments to real engineering stress environments, providing a key experimental platform and evaluation basis for the prevention and self-healing repair technology of cracks in deep underground engineering. Attached Figure Description

[0022] Figure 1 A schematic diagram of a test device for self-healing cracks in underground engineering structures; Figure 2 This is a schematic diagram of a seepage simulation platform.

[0023] Reference numerals: 1.1-Control unit; 1.2-Vacuum unit; 1.3-Metering unit; 2.1-Axial pressure pump; 2.2-Containing pressure pump; 3.1-Rock sample holder; 3.2-Pressure sensor; 3.3-Displacement sensor; 3.4-Self-healing material cavity; 4.1-Piston-type pressure vessel; 4.2-High-precision constant flow pump; 5.1-Buffer tube; 5.2-Dryer; 5.3-Vacuum pump; 5.4-Flow meter; 6.1-Integrated measurement and control system. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0025] Example 1 This embodiment provides a test device for crack self-healing under high confining pressure-shear-seepage coupling conditions, such as... Figure 1 As shown, it includes: a high-precision constant flow pump 4.2, a rock sample holder 3.1, a confining pressure pump 2.2, an axial pressure pump 2.1, a self-healing material injection system, a flow meter 5.4, and an integrated measurement and control system 6.1; The rock sample holder 3.1 is used to hold standard samples and is equipped with a confining pressure interface, an axial pressure interface, a seepage inlet interface, and a seepage outlet interface. The cylinder of the rock sample holder 3.1 is made of high-strength stainless steel alloy. It can hold Φ50×100 mm standard samples and can withstand confining pressure and axial pressure up to 30 MPa with an accuracy of 0.1% FS. The high-precision constant flow pump 4.2 is connected to the seepage inlet interface of the rock sample holder 3.1 through a high-pressure resistant pipeline. It is used to inject fluid or self-healing material into the sample. The flow rate range is 0.1-100 ml / min and the maximum working pressure is 20 MPa. The confining pressure pump 2.2 and the axial pressure pump 2.1 are respectively connected to the confining pressure interface and the axial pressure interface of the rock sample holder 3.1 through pipelines, and are used to apply independent confining pressure and axial stress to the sample. The maximum working pressure of the confining pressure pump 2.2 and the axial pressure pump 2.1 is 30 MPa. The maximum working pressure of the confining pressure pump 2.2 is 30 MPa, and the pressure resistance is up to 70 MPa. It is used to apply uniform pressure constraint to the sample. The axial pressure pump 2.1 has a range of 0-30 MPa and an accuracy of 0.1% FS. It is used to apply stable and adjustable shear displacement to the sample.

[0026] The self-healing material injection system is connected to the seepage inlet interface of the high-precision constant flow pump 4.2 and / or the rock sample holder 3.1, and is used to inject self-healing material into the fractures that have been sheared and disturbed; the self-healing material in the self-healing material injection system is disposed in the self-healing material cavity 3.4; The flow meter 5.4 includes a high-precision electronic balance connected to the seepage outlet interface of the rock sample holder 3.1, used to measure the mass of the seepage fluid in real time, with a scale division of 0.01 g and a measuring range of 2200 g; The integrated measurement and control system 6.1 is electrically connected to the sensors on the high-precision constant flow pump 4.2, confining pressure pump 2.2, axial pressure pump 2.1, rock sample holder 3.1, and flow meter 5.4. It is used to control each loading unit and collect and process test data, realizing the integrated and automated control of the entire process from sample saturation, stress loading, shear-seepage coupling, self-healing material injection to healing effect testing.

[0027] The self-healing test equipment for cracks in underground engineering structures is integrated into a seepage simulation platform. The seepage simulation platform includes a control unit 1.1, a vacuum unit 1.2, and a metering unit 1.3, such as... Figure 2 As shown.

[0028] Example 2 This embodiment provides a test device for crack self-healing under high confining pressure-shear-seepage coupling conditions, such as... Figure 1 As shown, it includes: a high-precision constant flow pump 4.2, a rock sample holder 3.1, a confining pressure pump 2.2, an axial pressure pump 2.1, a self-healing material injection system, a flow meter 5.4, and an integrated measurement and control system 6.1; The rock sample holder 3.1 is used to hold standard samples and is equipped with a confining pressure interface, an axial pressure interface, a seepage inlet interface, and a seepage outlet interface. The cylinder of the rock sample holder 3.1 is made of high-strength stainless steel alloy. It can hold Φ50×100 mm standard samples and can withstand confining pressure and axial pressure up to 30 MPa with an accuracy of 0.1% FS. The high-precision constant flow pump 4.2 is connected to the seepage inlet interface of the rock sample holder 3.1 through a high-pressure resistant pipeline. It is used to inject fluid or self-healing material into the sample. The flow rate range is 0.1-100 ml / min and the maximum working pressure is 20 MPa. The confining pressure pump 2.2 and the axial pressure pump 2.1 are respectively connected to the confining pressure interface and the axial pressure interface of the rock sample holder 3.1 through pipelines, and are used to apply independent confining pressure and axial stress to the sample. The maximum working pressure of the confining pressure pump 2.2 and the axial pressure pump 2.1 is 30 MPa. The maximum working pressure of the confining pressure pump 2.2 is 30 MPa, and the pressure resistance is up to 70 MPa. It is used to apply uniform pressure constraint to the sample. The axial pressure pump 2.1 has a range of 0-30 MPa and an accuracy of 0.1% FS. It is used to apply stable and adjustable shear displacement to the sample.

[0029] The self-healing material injection system is connected to the seepage inlet interface of the high-precision constant flow pump 4.2 and / or the rock sample holder 3.1, and is used to inject self-healing material into the fractures that have been sheared and disturbed; the self-healing material in the self-healing material injection system is disposed in the self-healing material cavity 3.4; The flow meter 5.4 includes a high-precision electronic balance connected to the seepage outlet interface of the rock sample holder 3.1, used to measure the mass of the seepage fluid in real time, with a scale division of 0.01 g and a measuring range of 2200 g; The integrated measurement and control system 6.1 is electrically connected to the sensors on the high-precision constant flow pump 4.2, confining pressure pump 2.2, axial pressure pump 2.1, rock sample holder 3.1, and flow meter 5.4. It is used to control each loading unit and collect and process test data, realizing the integrated and automated control of the entire process from sample saturation, stress loading, shear-seepage coupling, self-healing material injection to healing effect testing.

[0030] The self-healing test equipment for cracks in underground engineering structures is integrated into a seepage simulation platform. The seepage simulation platform includes a control unit 1.1, a vacuum unit 1.2, and a metering unit 1.3, such as... Figure 2 As shown.

[0031] In a specific embodiment, the rock sample holder 3.1 further includes a rubber sleeve, a tapered sleeve, a pressure cap, a plug, and a sealing device. Through the combination of the rubber sleeve, tapered sleeve, pressure cap, plug, and sealing device, a reliable seal between the confining pressure medium and the pore fluid is achieved under high pressure and shear displacement.

[0032] In a specific embodiment, an intermediate pressure vessel is also included. The intermediate pressure vessel is a piston-type pressure vessel 4.1, which is installed on the pipeline between the high-precision constant flow pump 4.2 and the rock sample holder 3.1. An isolation piston is provided inside to isolate the power fluid from the working medium and buffer pressure fluctuations. The maximum working pressure is 30MPa and the volume is 1000ml.

[0033] In a specific implementation, the high-precision constant flow pump 4.2 employs microcomputer control and stepper motor control, with the pump body and control system being independent units; it achieves precise and stable flow rate control from 0.1 to 100 ml / min, a maximum pore pressure of 20 MPa, and an accuracy of 0.1% FS. It utilizes a dual-cam drive mechanism, with two pump heads working alternately, resulting in stable output flow and minimal pressure fluctuations.

[0034] In a specific implementation, both the confining pressure pump 2.2 and the axial pressure pump 2.1 are high-precision manual pumps with stroke locking function and built-in safety valves.

[0035] In a specific implementation, a vacuum system is also included, which includes a vacuum pump 5.3, a vacuum gauge and valve pipelines, used to evacuate and exhaust the sample and fluid pipelines before the test.

[0036] In a specific embodiment, the vacuum system further includes a buffer tube 5.1 and a dryer 5.2 that are connected to each other.

[0037] Vacuum pump 5.3 is a 2XZ-4 type vacuum pump and buffer tube 5.1 is a ZR-5 type vacuum buffer container.

[0038] In a specific embodiment, the sensors on the rock sample holder 3.1 include a pressure sensor 3.2 and a displacement sensor 3.3.

[0039] Example 3 This embodiment provides a test method for crack self-healing under high confining pressure-shear-seepage coupling conditions, including the following steps: S1. Stress loading and sample saturation: The sample is loaded into the rock sample holder 3.1, and the confining pressure and axial pressure are applied to the target value and kept stable by the confining pressure pump 2.2 and the axial pressure pump 2.1 to simulate the in-situ stress state underground; then the sample is evacuated and fluid is injected to complete the sample saturation. S2. Benchmark seepage test: Under the set stress, start the high-precision constant flow pump 4.2 to inject fluid into the sample at a constant flow rate. After the flow stabilizes, calculate the initial permeability of the fracture by recording the stable flow rate and inlet pressure through the flow meter 5.4. S3. Shear-seepage coupling test: Under the conditions of maintaining confining pressure, axial pressure and constant seepage, shear displacement is applied to the sample by axial pressure pump 2.1, and the changes in shear force, shear displacement, pore pressure and real-time seepage flow are monitored and recorded simultaneously; S4. Self-healing material injection and self-healing process simulation: After shearing is completed or a specific shear displacement is reached, switch to the self-healing material injection system, inject self-healing material into the crack, and then carry out curing under stable confining pressure. S5. Healing effect test: After the curing is completed, under the same stress and boundary conditions as in step S3, a seepage test is conducted again. By comparing the changes in crack permeability before and after self-healing, the sealing effect of the self-healing material is quantitatively evaluated.

[0040] S6. Results Output: Throughout the experiment, this platform automatically collects all sensor data and processes it in real time; it can eventually automatically generate a comprehensive test report containing shear stress-displacement curves, permeability-shear displacement evolution curves, and injection pressure-time curves, providing complete data analysis for analyzing the mechanical-seepage behavior and self-healing efficiency of fractures under coupling effects.

[0041] In a specific implementation, in step S1, the target values ​​of the confining pressure and axial pressure can reach up to 30 MPa; The high-precision constant flow pump 4.2 provides a seepage flow rate range of 0.1-100 ml / min in steps S2 and S5.

[0042] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0043] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A test device for crack self-healing under high confining pressure-shear-seepage coupling conditions, characterized in that, include: High-precision constant flow pump (4.2), rock sample holder (3.1), confining pressure pump (2.2), axial pressure pump (2.1), self-healing material injection system, flow meter (5.4), and integrated measurement and control system (6.1). The rock sample holder (3.1) is used to hold standard samples and is equipped with a confining pressure interface, an axial pressure interface, a seepage inlet interface and a seepage outlet interface; The high-precision constant flow pump (4.2) is connected to the seepage inlet interface of the rock sample holder (3.1) through a high-pressure resistant pipeline. It is used to inject fluid or self-healing material into the sample. The flow rate range is 0.1-100 ml / min and the maximum working pressure is 20 MPa. The confining pressure pump (2.2) and the axial pressure pump (2.1) are respectively connected to the confining pressure port and the axial pressure port of the rock sample holder (3.1) through pipelines, and are used to apply independent confining pressure and axial stress to the sample. The maximum working pressure of the confining pressure pump (2.2) and the axial pressure pump (2.1) is 30 MPa. The self-healing material injection system is connected to the seepage inlet interface of the high-precision constant flow pump (4.2) and / or the rock sample holder (3.1) for injecting self-healing material into the fracture after shear disturbance; the self-healing material in the self-healing material injection system is disposed in the self-healing material cavity (3.4); The flow meter (5.4) includes a high-precision electronic balance connected to the seepage outlet interface of the rock sample holder (3.1) for real-time measurement of the mass of the seepage fluid, with a graduation value of 0.01 g; The integrated measurement and control system (6.1) is electrically connected to the sensors on the high-precision constant flow pump (4.2), confining pressure pump (2.2), axial pressure pump (2.1), rock sample holder (3.1), and flow meter (5.4) to control each loading unit and collect and process test data, so as to realize the integrated and automated control of the entire process from sample saturation, stress loading, shear-seepage coupling, self-healing material injection to healing effect testing.

2. The self-healing test device for fractures under high confining pressure-shear-seepage coupling conditions according to claim 1, characterized in that, The rock sample holder (3.1) also includes a rubber sleeve, a tapered sleeve, a pressure cap, a plug, and a sealing device. The combination of the rubber sleeve, tapered sleeve, pressure cap, plug, and sealing device enables a reliable seal between the confining pressure medium and the pore fluid under high pressure and shear displacement.

3. The self-healing test device for fractures under high confining pressure-shear-seepage coupling conditions according to claim 1, characterized in that, It also includes an intermediate pressure vessel, which is a piston-type pressure vessel (4.1) installed on the pipeline between the high-precision constant flow pump (4.2) and the rock sample holder (3.1). It is equipped with an isolation piston inside to isolate the power fluid from the working medium and buffer pressure fluctuations. The maximum working pressure is 30MPa and the volume is 1000ml.

4. The self-healing test device for fractures under high confining pressure-shear-seepage coupling conditions according to claim 1, characterized in that, The high-precision constant flow pump (4.2) is controlled by a microcomputer and a stepper motor. The pump body and the control system are independent units. It adopts a double cam drive mechanism, with the two pump heads working alternately, resulting in stable output flow and small pressure fluctuations.

5. The self-healing test device for fractures under high confining pressure-shear-seepage coupling conditions according to claim 1, characterized in that, Both the confining pressure pump (2.2) and the axial pressure pump (2.1) are high-precision manual pumps with stroke locking function and built-in safety valves.

6. The test equipment for crack self-healing under high confining pressure-shear-seepage coupling conditions according to claim 1, characterized in that, It also includes a vacuum system, which includes a vacuum pump (5.3), a vacuum gauge and valve lines, for evacuating and venting the sample and fluid lines before the test.

7. The self-healing test device for fractures under high confining pressure-shear-seepage coupling conditions according to claim 6, characterized in that, The vacuum system also includes a buffer tube (5.1) and a dryer (5.2) that are connected to each other.

8. The self-healing test device for fractures under high confining pressure-shear-seepage coupling conditions according to claim 1, characterized in that, The sensors on the rock sample holder (3.1) include a pressure sensor (3.2) and a displacement sensor (3.3).

9. A method for testing crack self-healing under high confining pressure-shear-seepage coupling conditions using the equipment described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Stress loading and sample saturation: The sample is loaded into the rock sample holder (3.1), and the confining pressure and axial pressure are applied to the target value and kept stable by the confining pressure pump (2.2) and the axial pressure pump (2.1) to simulate the in-situ stress state underground; then the sample is evacuated and fluid is injected to complete the sample saturation; S2. Benchmark seepage test: Under the set stress, start the high-precision constant flow pump (4.2) to inject fluid into the sample at a constant flow rate. After the flow stabilizes, calculate the initial permeability of the fracture by recording the stable flow rate and inlet pressure through the flow meter (5.4). S3. Shear-seepage coupling test: Under the conditions of maintaining confining pressure, axial pressure and constant seepage, shear displacement is applied to the sample by axial pressure pump (2.1), and the changes of shear force, shear displacement, pore pressure and real-time seepage flow are monitored and recorded simultaneously; S4. Self-healing material injection and self-healing process simulation: After shearing is completed or a specific shear displacement is reached, switch to the self-healing material injection system, inject self-healing material into the crack, and then carry out curing under stable confining pressure. S5. Healing effect test: After the curing is completed, under the same stress and boundary conditions as in step S3, a seepage test is conducted again. By comparing the changes in crack permeability before and after self-healing, the sealing effect of the self-healing material is quantitatively evaluated. S6. Results Output: Throughout the experiment, this platform automatically collects all sensor data and processes it in real time; it can eventually automatically generate a comprehensive test report containing shear stress-displacement curves, permeability-shear displacement evolution curves, and injection pressure-time curves, providing complete data analysis for analyzing the mechanical-seepage behavior and self-healing efficiency of fractures under coupling effects.

10. The method for self-healing fractures under high confining pressure-shear-seepage coupling conditions according to claim 9, characterized in that, In step S1, the target values ​​of the confining pressure and axial pressure can reach up to 30 MPa; The high-precision constant flow pump (4.2) provides a seepage flow rate range of 0.1-100 ml / min in steps S2 and S5.

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