'Slurry-rock' combination permeability evolution research test device and method

Abstract

The invention belongs to the technical field of geotechnical engineering, and particularly relates to a slurry-rock combination permeability evolution research test device and method.A confining pressure controller loads confining pressure to a rock sample in a main pressure chamber to control the pressure of the outer side of the rock sample, and one end of the confining pressure controller is connected with a monitoring system and used for controlling the magnitude of applied pressure; the other end is connected with the main pressure chamber; the axial pressure controller applies axial pressure through an upper bearing platform of the main pressure chamber, the axial pressure controller is respectively connected with the main pressure chamber and the monitoring system, the water supply pressurization control system and the high-pressure grouting system are connected with the main pressure chamber through pipelines, and the rock fracture prefabricating device adopts a three-section mold to provide a required standard rock sample for a test. The crack filling bodies with different shapes, roughness and widths are manufactured in advance by using the solid paraffin, and the built-in cracks meeting different requirements can be manufactured in the process of manufacturing the standard rock sample according to the characteristic that the crack filling bodies are melted when being heated, so that the method is simpler and more practical, and the actual requirements are better met.

Description

Technical Field

[0001] The present invention belongs to the field of geotechnical engineering technology, and specifically relates to a test device and method for studying the permeability evolution of a "slurry-rock" combination, and studies the permeability evolution of the "slurry-rock" combination based on the slurry-rock coupling effect. Background Art

[0002] The existence of weak structural surfaces including faults, joints, and fissures has an important impact on the safe construction of underground projects such as tunnel engineering, foundation pit excavation, and mining, and often leads to geological disasters such as rock instability and water inrush, such as coal mine water inrush, tunnel and foundation pit water inrush, and surrounding rock instability and collapse. The existence of cracks in the rock mass reduces the strength and stability of the rock on the one hand, and is also a good water channel on the other hand. Due to the complexity, concealment, and unpredictability of underground engineering geological problems, problems such as water inrush, sand burst, and water and sand inrush have always troubled us. At present, grouting reinforcement is widely used in water hazard prevention and control. By blocking the main water-conducting cracks, the purpose of water control, water isolation, and reinforcement of surrounding rocks is achieved. Practice has shown that grouting plays a great role in promoting the safe production of underground projects.

[0003] Grouting in fractured rock mass, grouting theory, grouting materials, temperature, rock mass fracture characteristics, groundwater flow characteristics are important influencing factors for analyzing the grouting diffusion law, and the physical and mechanical properties test of fractured rock mass before and after grouting is the basis for analyzing the grouting effect. In actual engineering, the cracks in the rock mass are unevenly distributed and have different characteristics. There is an obvious "biased flow effect" in the flow of slurry during the grouting process. The newly generated and original small cracks during the grouting process cannot be effectively blocked, resulting in the instability of rock mass seepage after grouting. In addition, the influence of strong ground stress and temperature at a certain depth below the ground needs to be considered. Indoor fractured rock mass grouting research can study the initiation, expansion, and blocking of fractures in detail, which can better serve the study of grouting mechanism. At present, there are problems in the grouting of water-rich fractured rock mass and the study of the properties of magma-rock assemblages:

[0004] (1) Grouting of prefabricated fractured rock is the main method of laboratory research at present. However, in current research, prefabricated fractures are mostly flat fractures on the rock surface or through fractures. Only the length and opening of the fractures can be considered without considering the influence of roughness. At the same time, through fracture grouting cannot explore the influence of the grouting process on the change of fracture opening, such as the high-pressure grouting filling device, system and method for fractures of standard rock specimens disclosed in CN114993787A. If the broken rock mass is full of through fractures, the grouting reinforcement mechanism is obviously different from the fracture grouting, so the research method is also different, such as the disclosed model test device and test method for dynamic water grouting reinforcement of water-rich broken rock strata.

[0005] (2) Existing grouting of fractured rock mass rarely considers the influence of surrounding rock stress and seepage water pressure, and no axial pressure or confining pressure is applied before grouting. The influence of deep high ground stress on rock mass is immeasurable, and direct grouting of prefabricated fractures is too idealistic. Before grouting prefabricated fractured rock mass, the influence of ground stress should be considered first, the expansion law of fractures should be analyzed, and then the grouting effect should be studied, which is more in line with the engineering reality of disordered natural fractures. How to achieve safe high-pressure grouting while considering the seepage effect is also one of the problems that need to be solved urgently.

[0006] (3) Grouting reinforcement is widely used in engineering, but cases of seepage instability of rock mass after grouting also occur from time to time. The stability of slurry-rock combination is also one of the problems that need to be solved urgently in grouting engineering. Some scholars have studied the permeability of slurry-rock combination, such as the literature "Yuan Shichong. Study on the diffusion mechanism of slurry in curtain grouting of fractured rock mass in deep mines and the mining effect of "slurry-rock" combination [D]. China University of Mining and Technology, 2023" and "Zhang Peisen, Xu Daqiang, Li Tenghui, et al. Experimental study on seepage characteristics of fractured sandstone before and after grouting and mechanical properties after grouting [J]. Rock and Soil Mechanics, 2023, 44 (S1): 12-26", but the study on the evolution of mechanical properties of slurry-rock combination after grouting based on fracture network needs to be further deepened.

[0007] Therefore, it is necessary to design a test device and method for studying the permeability evolution of the "slurry-rock" combination, a prefabricated fracture three-dimensional high-pressure grouting device that comprehensively considers the confining pressure, axial pressure, seepage water pressure and grouting pressure, and use this as a basis to study the stability of the slurry-rock combination. Summary of the invention

[0008] The purpose of the present invention is to provide a test device and method for studying the permeability evolution of a "slurry-rock" combination, to solve the problem of prefabrication of internal cracks in standard rock samples for indoor tests, and to consider the influence of ground stress and seepage pressure on the permeability damage and rupture mechanism of fractured rock mass and the grouting effect, so as to realize grouting of fracture network rock mass and the stability study of slurry-rock combination.

[0009] To achieve the above object, the present invention is implemented through the following technical solutions:

[0010] In the first aspect, the present invention provides a test device for studying the permeability evolution of a "slurry-rock" combination, comprising a main pressure chamber, an axial pressure controller, a confining pressure controller, a water supply pressurization control system, a high-pressure grouting system and a monitoring system; the confining pressure controller controls the outer pressure of a rock sample by loading confining pressure on the rock sample in the main pressure chamber, one end of the confining pressure controller is connected to the monitoring system for controlling the pressure application, and the other end is connected to the main pressure chamber; the axial pressure controller applies axial pressure through the upper platform of the main pressure chamber, the axial pressure controller is connected to the main pressure chamber and the monitoring system respectively, the water supply pressurization control system and the high-pressure grouting system are connected to the main pressure chamber through pipelines, and the rock fracture prefabrication device adopts a three-petal mold to provide the required standard rock samples for the test.

[0011] As a further technical solution of the present invention, the main pressure chamber is a core device for grouting reinforcement of fractured rock mass, including a slurry outlet pipe flowmeter, a slurry outlet pipe, a sample placement platform, an annular sensor, a rock sample, a built-in fracture, a rubber sleeve, a pressure relief valve, an upper support platform, a lower support platform, a fixing bracket, fixing bolts, a confining pressure gauge and a grouting flowmeter. The upper support platform and the lower support platform of the cylindrical structure are fixed by fixing bolts through two vertical fixing brackets. The height between the upper support platform and the lower support platform is adjustable. The sample placement platform is arranged between the upper support platform and the lower support platform. The rock sample with built-in fracture is placed on the sample placement platform and the height can be appropriately adjusted to facilitate the placement of the rock. The prepared rock sample is placed on the sample setting platform and in contact with the lower supporting platform. The rubber sleeve is put on the outside of the rock sample to fix the rock sample on the sample setting platform; the annular sensor is arranged on the outside of the rubber sleeve; a pressure relief valve, a confining pressure gauge and a grouting flowmeter are arranged on the upper part of the main pressure chamber, a slurry pipe flowmeter is arranged on the bottom, a water inlet hole is connected to the water inlet pipe and the water storage tank to ensure the seepage water pressure of the fractured rock mass, and the slurry inlet is connected to the slurry storage tank through the grouting pipe; the main pressure chamber is arranged on the supporting platform, and a waste liquid collection box is inside the supporting platform. The slurry pipe at the bottom of the main pressure chamber is connected to the waste liquid collection box, and the waste liquid collection box is used to collect waste liquid from the slurry pipe process.

[0012] As a further technical solution of the present invention, a water supply pressure control system is used to simulate the expansion of rock grouting cracks below the actual groundwater level. When the indoor test is for mudstone or sandstone, a water supply pressure control system is set, and it is not set in other cases; the water supply pressure control system includes a water pump, a water inlet pipe, a water pressure gauge and a water storage tank; a water pressure gauge is provided between the water pump and the water storage tank, and the water supply pressure control system is connected to the main pressure chamber through the water inlet pipe, and the water inlet pipe passes through the upper support platform into the main pressure chamber; the water supply pressure control system is connected to the control box, and the control box is used to control the water supply pressure.

[0013] As a further technical solution of the present invention, the grouting system includes a slurry storage tank and a grouting pump. The slurry storage tank is connected to the main pressure chamber pipeline, the grouting storage tank is used to prepare and store slurry, the grouting pump is respectively connected to the slurry storage tank and the control box, and the control box is used to control the grouting pressure.

[0014] As a further technical solution of the present invention, the monitoring system is composed of a computer, an axial pressure controller, a confining pressure controller and an annular sensor in the device, which is used to obtain relevant data during the test process, including confining pressure, axial pressure and water pressure; the computer, axial pressure controller and confining pressure controller are used to control the given pressure design value and collect and summarize data through sensors, and finally present the data monitoring results on the computer.

[0015] In a second aspect, the present invention provides a method for studying the permeability evolution of a "magma-rock" combination, and the specific steps are as follows:

[0016] S1. Preparation of prefabricated fractured rock samples: A three-flap mold is used for rock sample preparation. Similar materials are laid on the bottom to the designed position, a paraffin fracture network model is placed, and similar materials are laid on the sides to the level of the top of the model. The sample is vibrated and hammered slowly to form and meet the design standard. After the sample is formed, it is placed in a 65°C constant temperature box. After the solid paraffin is melted, the liquid paraffin is pumped out by a small water pump, and then cured under standard conditions to obtain the rock sample;

[0017] S2. Install and check the device: first connect each system and check it, then arrange the pressure sensor and water pressure sensor, connect the sensor to the data acquisition instrument and the computer, set the relevant parameters in the control software on the computer, including the application and pressure level of confining pressure, axial pressure, water pressure, and finally adjust the water pressure gauge and grouting pressure gauge in the device to read 0;

[0018] S3. Slurry preparation: Prepare the slurry according to the test requirements and place the prepared slurry in the slurry storage tank. Before grouting, pay attention to stirring the slurry evenly to prevent slurry precipitation. If the grouting time is too long, a retarder needs to be prepared to delay the slurry solidification time;

[0019] S4. Place rock sample: Place the prepared rock sample on the sample placement table in the main pressure chamber, fix the lower part and connect the grouting pipe to the upper part; turn on the water supply pressure control system, check the water pipe connection, and slowly apply pressure to the design value to simulate the confining pressure;

[0020] S5. Grouting test: During the test, the changes of various stresses, grouting pressure and grouting volume during the grouting process are recorded to facilitate subsequent data analysis. After the test is completed, the grouting reinforcement body is obtained;

[0021] S6. Standard curing of rock samples after grouting: The grouting reinforcement body is subjected to standard curing for 3 days, 7 days, and 28 days respectively to ensure that the grouting reinforcement body is not damaged, and the rock sample is ground with a rock grinder to obtain a rock sample with a diameter of 50×H100 mm and a flat double-end surface;

[0022] S7, repeat the above steps to obtain a rock sample for the control group;

[0023] S8. Use the GDS triaxial testing system, electro-hydraulic servo universal testing machine, and scanning electron microscope to acquire and analyze data on the uniaxial compressive strength, shear strength, permeability, and slurry-rock interface effect of the assembly, and study the evolution law of the mechanical properties of the slurry-rock assembly.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The high-pressure grouting device of the present invention takes into account the influence of seepage pressure and surrounding rock pressure. In actual grouting projects, the diffusion of slurry generally occurs in aquifers with relatively broken rock mass and appropriate rock layer thickness, and the influence of seepage water pressure cannot be ignored when the burial depth is large. Existing indoor grouting tests generally do not consider the influence of seepage water pressure. The present invention sets seepage water pressure in the grouting device, which is more practical in terms of function.

[0026] (2) The study of the stability of magma-rock assemblages can obtain the grouting reinforcement effect under different fracture conditions, analyze the main controlling factors of stability, and obtain the evolution characteristics of the permeability and compressive and shear strength of the assemblages, providing a reference for studying the permeability stability of magma-rock assemblages, further improving the grouting reinforcement effect, and revealing the grouting mechanism of fracture networks.

[0027] (3) Using solid paraffin wax to pre-make crack filling bodies of different shapes, roughness, and widths, built-in cracks that meet different needs can be made during the process of making standard rock samples according to their melting characteristics when heated. Considering the complexity of rock crack damage in actual processes, existing methods are dedicated to penetrating simpler cracks such as single cracks, and cannot achieve the preparation of complex crack networks. The device and method in the present invention are simple, practical, and more in line with actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural diagram of the experimental device for studying the permeability evolution of the "magma-rock" combination described in the present invention.

[0029] Figure 2 It is a cross-sectional structural diagram of the sample placement platform described in the present invention.

[0030] Figure 3 This is a rock sample diagram of the built-in through and non-through fracture network described in the invention.

[0031] Figure 4 This is a flow chart of the experimental method for studying the permeability evolution of the "magma-rock" combination described in the present invention.

[0032] In the figure: 1-slurry outlet pipe flow meter, 2-slurry outlet pipe, 3-sample placement platform, 4-annular sensor, 5-rock sample, 5-1-built-in fracture, 6-rubber sleeve, 7-main pressure chamber, 7-1 pressure relief valve, 7-2 upper support platform, 7-3 lower support platform, 8-fixed bracket, 9-fixing bolt, 10-confining pressure gauge, 11-grouting flow meter, 12-grouting pressure gauge, 13-water inlet pipe, 14-water pressure gauge, 15-water supply and pressurization system, 16-water storage tank, 17-slurry storage tank, 18-grouting system, 19-grouting pump, 20-control box, 21-axial pressure controller, 22-confining pressure controller, 23-monitoring system, 24-support platform. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation examples.

[0034] Embodiment 1:

[0035] like Figure 1 As shown, this embodiment provides a "slurry-rock" combination permeability evolution research test device, including a main pressure chamber 7, an axial pressure controller 21, a confining pressure controller 22, a water supply pressurization control system 15, a high-pressure grouting system 18 and a monitoring system 23; the confining pressure controller 22 controls the outer pressure of the rock sample 5 by loading the confining pressure on the rock sample 5 in the main pressure chamber 7, and can more realistically simulate the influence of the ground stress on the sample grouting; one end of the confining pressure controller 22 is connected to the monitoring system 23 for controlling the pressure application, and the other end is connected to the main pressure chamber 7; the axial pressure controller 21 applies axial pressure through the upper platform 7-2 of the main pressure chamber 7 to apply pressure to the rock sample 5 after grouting, so as to analyze the compressive strength of the rock sample 5 after grouting reinforcement, the axial pressure controller 21 is respectively connected to the main pressure chamber 7 and the monitoring system 23, the water supply pressurization control system 15 and the high-pressure grouting system 18 are connected to the main pressure chamber 7 through pipelines, and the prefabricated standard sample of fractured rock is made of a three-petal mold.

[0036] Specifically, the main pressure chamber 7 is a core device for grouting reinforcement of fractured rock mass, including a slurry outlet pipe flowmeter 1, a slurry outlet pipe 2, a sample placement platform 3, an annular sensor 4, a rock sample 5, a built-in fracture 5-1, a rubber sleeve 6, a pressure relief valve 7-1, an upper support platform 7-2, a lower support platform 7-3, a fixing bracket 8, a fixing bolt 9, a confining pressure gauge 10 and a grouting flowmeter 11. The upper support platform 7-2 and the lower support platform 7-3 of the cylindrical structure are fixed by two vertical fixing brackets 8 with fixing bolts 9. The height between the upper support platform 7-2 and the lower support platform 7-3 is adjustable. The sample placement platform 3 is arranged between the upper support platform 7-2 and the lower support platform 7-3. The rock sample 5 with the built-in fracture 5-1 is placed on the sample placement platform 3 and the height can be appropriately adjusted to facilitate the adjustment of the sample. The rock sample 5 is placed, and the prepared rock sample 5 is placed on the sample placement platform and in contact with the lower support platform 7-3. The rubber sleeve 6 is sleeved on the outside of the rock sample 5 to fix the rock sample 5 on the sample placement platform 3; the annular sensor 4 is arranged on the outside of the rubber sleeve 6, and the upper part of the main pressure chamber is provided with a pressure relief valve 7-1, a confining pressure gauge 10 and a grouting flowmeter 11, and the bottom is provided with a slurry pipe flowmeter 1, and the water inlet hole is connected to the water inlet pipe 13 and connected to the water storage tank 16 to ensure the seepage water pressure of the fractured rock mass, and the slurry inlet is connected to the slurry storage tank 17 through the grouting pipe; the main pressure chamber 7 is arranged on the support platform 24, and the support platform 24 has a waste liquid collection box, and the slurry pipe 2 at the bottom of the main pressure chamber 7 is connected to the waste liquid collection box, and the waste liquid collection box is used to collect waste liquid from the slurry pipe 2 flow.

[0037] Specifically, the water supply pressure control system 15 is used to simulate the expansion of rock grouting cracks below the actual groundwater level. When the indoor test is aimed at aquiclude materials such as mudstone or highly permeable materials such as sandstone, and the specimens made of similar materials have good impermeability (mudstone) or high permeability (sandstone) and do not have the ability to disintegrate when exposed to water, the water supply pressure control system 15 is set, and it is not set in other cases; the water supply pressure control system 15 includes a water inlet pipe 13, a water pressure gauge 14 and a water storage tank 16; the water supply pressure control system 15 is connected to the main pressure chamber 7 through the water inlet pipe 13, and the water inlet pipe 13 passes through the upper support platform 7-2 to enter the main pressure chamber 7; the water supply pressure control system 15 is connected to the control box 20, and the control box 20 is used to control the water supply pressure.

[0038] Specifically, the grouting system 18 includes a slurry storage tank 17 and a grouting pump 19. The slurry storage tank 17 is connected to the main pressure chamber 7 by a pipeline. The grouting storage tank 17 is used to prepare and store slurry. The grouting pump 19 is respectively connected to the slurry storage tank 17 and a control box 20. The control box 20 is used to control the grouting pressure.

[0039] Embodiment 2:

[0040] This embodiment uses a "magma-rock" combination permeability evolution research test device to conduct experiments. Figure 4 As shown, the specific steps are as follows:

[0041] S1. Rock sample preparation: as attached Figure 3 The figure shows a schematic diagram of prefabricated fractured rock samples, including through-fractured rock samples and non-through-fractured rock samples. A three-flap mold is used when making rock sample 5. Similar materials are laid on the bottom to the designed position, a paraffin fracture network model is placed, and similar materials are laid on the sides to the level of the top of the model. The sample is formed by vibration and slow hammering to meet the design standard. After the sample is formed, it is placed in a 65°C constant temperature box. After the solid paraffin is melted, the liquid paraffin is pumped out by a small water pump, and then it is cured under standard conditions to obtain rock sample 5.

[0042] S2. Installation and inspection of the device: first connect each system and inspect it, then arrange the pressure sensor and water pressure sensor, connect the sensor to the data acquisition instrument and the computer, set the relevant parameters in the control software on the computer, including the application and pressure level of confining pressure, axial pressure, water pressure, and finally adjust the water pressure gauge 14 and grouting pressure gauge 12 in the device to read 0;

[0043] S3, slurry preparation: slurry is prepared according to the experimental design plan, and the prepared slurry is placed in the slurry storage tank 17. Before grouting, the slurry should be stirred evenly before grouting to prevent slurry precipitation. If the grouting time is too long, a retarder should be prepared to delay the slurry solidification time;

[0044] S4. Rock sample placement: Place the prepared rock sample 5 on the sample placement table 3 of the main pressure chamber 7, fix the lower part and connect the grouting pipe to the upper part. Open the water supply pressure control system 15, check the water pipe connection, and slowly apply pressure to the design value to simulate the confining pressure;

[0045] S5. Grouting test: During the test, the changes of various stresses, grouting pressure and grouting volume during the grouting process are recorded to facilitate subsequent data analysis. After the test is completed, the grouting reinforcement body is obtained;

[0046] S6. Standard maintenance of rock samples after grouting: The grouting reinforcement body is subjected to standard maintenance for 3d, 7d, and 28d respectively to ensure that the grouting reinforcement body is not damaged, and the rock sample 5 is ground with a rock grinder to obtain a rock sample 5 with a size of φ50×H100 mm and flat double end surfaces.

[0047] S7, control rock sample preparation: repeat the above steps to obtain a control group rock sample;

[0048] S8. Data analysis: Use the GDS triaxial testing system, electro-hydraulic servo universal testing machine, and scanning electron microscope to obtain and analyze the data of the uniaxial compressive strength, shear strength, permeability, and slurry-rock interface effect of the assembly, and study the evolution law of the mechanical properties of the slurry-rock assembly.

[0049] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0050] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A test device for studying the permeability evolution of a "magma-rock" combination, characterized in that: It consists of a main pressure chamber, an axial pressure controller, a confining pressure controller, a water supply and pressurization control system, a high-pressure grouting system and a monitoring system; the confining pressure controller controls the outer pressure of the rock sample by loading the confining pressure on the rock sample in the main pressure chamber, one end of the confining pressure controller is connected to the monitoring system to control the pressure application, and the other end is connected to the main pressure chamber; the axial pressure controller applies axial pressure through the upper platform of the main pressure chamber, the axial pressure controller is connected to the main pressure chamber and the monitoring system respectively, the water supply and pressurization control system and the high-pressure grouting system are connected to the main pressure chamber through pipelines, and the rock fracture prefabrication device adopts a three-petal mold to provide the required standard rock samples for the test.

2. The "magma-rock" combination permeability evolution research test device according to claim 1 is characterized in that: The main pressure chamber is the core device for grouting reinforcement of fractured rock mass, including a grouting pipe flowmeter, a grouting pipe, a sample placement platform, an annular sensor, a rock sample, a built-in fracture, a rubber sleeve, a pressure relief valve, an upper bearing, a lower bearing, a fixing bracket, fixing bolts, a confining pressure gauge and a grouting flowmeter. The upper bearing and the lower bearing of the cylindrical structure are fixed with fixing bolts through two vertical fixing brackets. The height between the upper bearing and the lower bearing is adjustable. The sample placement platform is set between the upper bearing and the lower bearing. The rock sample with built-in fracture is placed on the sample placement platform and the height can be adjusted appropriately to facilitate the placement of the rock sample. The sample is placed on the sample setting platform and in contact with the lower supporting platform. The rubber sleeve is put on the outside of the rock sample to fix the rock sample on the sample setting platform. The annular sensor is arranged on the outside of the rubber sleeve. A pressure relief valve, a confining pressure gauge and a grouting flowmeter are arranged on the upper part of the main pressure chamber, and a slurry pipe flowmeter is arranged at the bottom. The water inlet hole is connected to the water inlet pipe and the water storage tank to ensure the seepage water pressure of the fractured rock mass. The slurry inlet is connected to the slurry storage tank through the grouting pipe. The main pressure chamber is arranged on the supporting platform, and there is a waste liquid collection box in the supporting platform. The slurry pipe at the bottom of the main pressure chamber is connected to the waste liquid collection box, and the waste liquid collection box is used to collect waste liquid from the slurry pipe process.

3. The "magma-rock" combination permeability evolution research test device according to claim 2 is characterized in that: The water supply pressure control system is used to simulate the expansion of rock grouting cracks below the actual groundwater level. When the indoor test is for mudstone or sandstone, the water supply pressure control system is set up, and it is not set up in other cases; the water supply pressure control system includes a water pump, a water inlet pipe, a water pressure gauge and a water storage tank; a water pressure gauge is set between the water pump and the water storage tank, and the water supply pressure control system is connected to the main pressure chamber through the water inlet pipe, and the water inlet pipe passes through the upper platform into the main pressure chamber; the water supply pressure control system is connected to the control box, and the control box is used to control the water supply pressure.

4. The "magma-rock" combination permeability evolution research test device according to claim 3 is characterized in that: The grouting system includes a slurry storage tank and a grouting pump. The slurry storage tank is connected to the main pressure chamber pipeline and is used to prepare and store slurry. The grouting pump is respectively connected to the slurry storage tank and a control box, and the control box is used to control the grouting pressure.

5. The "magma-rock" combination permeability evolution research test device according to claim 4 is characterized in that: The monitoring system consists of a computer, an axial pressure controller, a confining pressure controller and an annular sensor inside the device, which is used to obtain relevant data during the test, including confining pressure, axial pressure and water pressure; the computer, axial pressure controller and confining pressure controller are used to control the given pressure design value and collect and summarize data through sensors, and finally present the data monitoring results on the computer.

6. A method for studying the permeability evolution of a "magma-rock" combination, characterized in that: The method is implemented by the device as claimed in claim 5, and the specific steps are as follows: S1. Preparation of prefabricated fractured rock samples: A three-flap mold is used for rock sample preparation. Similar materials are laid on the bottom to the designed position, a paraffin fracture network model is placed, and similar materials are laid on the sides to the level of the top of the model. The sample is vibrated and hammered slowly to form and meet the design standard. After the sample is formed, it is placed in a 65°C constant temperature box. After the solid paraffin is melted, the liquid paraffin is pumped out by a small water pump, and then cured under standard conditions to obtain the rock sample; S2. Install and check the device: first connect each system and check it, then arrange the pressure sensor and water pressure sensor, connect the sensor to the data acquisition instrument and the computer, set the relevant parameters in the control software on the computer, including the application and pressure level of confining pressure, axial pressure, water pressure, and finally adjust the water pressure gauge and grouting pressure gauge in the device to read 0; S3. Slurry preparation: Prepare the slurry according to the test requirements and place the prepared slurry in the slurry storage tank. Before grouting, pay attention to stirring the slurry evenly to prevent slurry precipitation. If the grouting time is too long, a retarder needs to be prepared to delay the slurry solidification time; S4. Place rock sample: Place the prepared rock sample on the sample placement table of the main pressure chamber, fix the lower part, and connect the grouting pipe to the upper part; Open the water supply pressure control system, check the water pipe connection, and slowly apply pressure to the design value to simulate the confining pressure; S5. Grouting test: During the test, the changes of various stresses, grouting pressure and grouting volume during the grouting process are recorded to facilitate subsequent data analysis. After the test is completed, the grouting reinforcement body is obtained; S6. Standard curing of rock samples after grouting: The grouting reinforcement body is subjected to standard curing for 3 days, 7 days, and 28 days respectively to ensure that the grouting reinforcement body is not damaged, and the rock sample is ground with a rock grinder to obtain a rock sample with a diameter of 50×H100 mm and a flat double-end surface; S7, repeat the above steps to obtain a rock sample for the control group; S8. Use the GDS triaxial testing system, electro-hydraulic servo universal testing machine, and scanning electron microscope to acquire and analyze data on the uniaxial compressive strength, shear strength, permeability, and slurry-rock interface effect of the assembly, and study the evolution law of the mechanical properties of the slurry-rock assembly.

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