A test apparatus for simulating bentonite hydration intrusion into a single fracture in granite

Abstract

This invention discloses a test device for simulating bentonite hydration intrusion into a single fracture of granite, belonging to the field of simulation test and detection technology. This invention utilizes an externally connected recirculating oil circuit system with an oil inlet and outlet, coupled with an electric heating unit within the oil tank, to achieve precise and stable temperature control of the circulating oil. This facilitates uniform and efficient heat transfer within the container cavity, thereby constructing a highly uniform and stable temperature field outside the flexible membrane enveloping the sample. Simultaneously, a rubber layer isolates the conductive oil from the externally circulating oil, ensuring that resistivity imaging monitoring using electrodes within the rubber layer is not interfered with by the external oil circulation. This combination effectively solves the problems of temperature field simulation distortion and slow control response in traditional devices under high confining pressure conditions, greatly improving the simulation realism of the heat-water-mechanical interaction during THMC coupling.

Description

Technical Field

[0001] This invention relates to the field of simulation testing technology, and in particular to a test device for simulating bentonite hydration intrusion into a single fracture of granite. Background Technology

[0002] In the deep geological disposal of high-level radioactive waste, the self-sealing effect of bentonite barriers expanding upon contact with water and penetrating the surrounding rock fissures is crucial for ensuring long-term safety. However, this process occurs in a complex coupled environment of decay heat (T), groundwater (H), geostress (M), and chemical reaction (C) (THMC), and existing laboratory simulation techniques have significant limitations.

[0003] Current devices struggle to accurately construct and control a uniform and stable temperature field (such as simulating decay heat rise) inside the sample while applying high confining pressures of tens of megapascals to simulate real ground stress. Common heating methods can easily interfere with stress uniformity or cause high-pressure sealing problems, leading to temperature field distortion and severely affecting the simulation realism of processes such as bentonite hydration reaction and thermo-hydraulic-mechanical coupling. Furthermore, there is a lack of effective, non-invasive in-situ monitoring methods for the dynamic evolution of intrusion morphology within cracks, and traditional terminal sampling or invasive sensor placement can damage the integrity of the sample.

[0004] Therefore, there is an urgent need to develop an experimental device that can simultaneously and accurately simulate the temperature-seepage-stress field under high confining pressure and integrate non-invasive in-situ monitoring, so as to reveal the true mechanism of bentonite intrusion under THMC coupling and provide key experimental evidence for safety assessment. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies in simulating bentonite hydration intrusion into single fractures of granite, where it is difficult to accurately and stably control the temperature field of the sample while simulating real stress, thus affecting the realism of the simulation test. Therefore, this invention proposes a test device for simulating bentonite hydration intrusion into single fractures of granite.

[0006] To address the problems existing in the prior art, the present invention adopts the following technical solution:

[0007] A test device for simulating bentonite hydration intrusion into granite with a single fracture includes a rigid container. Inside the rigid container, a flexible membrane and a rubber layer are arranged sequentially from the inside out. Conductive oil is filled between the flexible membrane and the rubber layer. An insulating cylinder is fixedly installed between the flexible membrane and the rubber layer, and the end wall of the insulating cylinder is designed with a hollow structure. Electrode plates are fixedly installed on the inner wall of the insulating cylinder. An oil inlet and an oil outlet are fixedly connected to the outer end walls of both ends of the rigid container, respectively. Both the oil inlet and the oil outlet are externally connected to an oil pump, and the oil pump is externally connected to an oil tank. An electric heating unit is installed inside the oil tank. A water injection pipe connected to the interior of the flexible membrane is fixedly installed at the center of one end of the rigid container. The water injection pipe is externally connected to a constant flow pump. A granite sample is wrapped inside the flexible membrane, and a pre-fabricated fracture is formed inside the granite sample that connects with the water injection pipe. A bentonite sample that is tightly attached to the granite sample is wrapped inside the flexible membrane on the side away from the water injection pipe.

[0008] Preferably, a water tank immersed in oil is fixedly installed inside the oil tank, and the water tank stores a simulated solution, with a constant flow pump connected to the water tank.

[0009] Preferably, a support cylinder is fixedly installed inside the rigid container and sleeved on the outside of the rubber layer, and the end wall of the support cylinder is set as a hollow structure.

[0010] Preferably, the rigid container has an opening in the middle, and the opening has a stepped structure, and the rigid container has an opening and closing mechanism on the outside.

[0011] Preferably, the rigid container is divided into two cylindrical structures from the opening, and a connecting pipe connects the two cylindrical structures. The two cylindrical structures have the same depth. The length of the granite sample is greater than the depth of a single cylindrical structure, and the length of the bentonite sample is less than the depth of a single cylindrical structure. The mating surfaces of the granite sample and the bentonite sample are misaligned with the opening.

[0012] Preferably, the opening and closing mechanism includes a support, a cylindrical structure on one side of the rigid container is fixedly connected to the support, a slide rail is fixedly installed on the support, and a hydraulic push rod is arranged parallel to the slide rail. The cylindrical structure on the other side of the rigid container is slidably connected to the slide rail and fixedly connected to the piston rod of the hydraulic push rod.

[0013] Preferably, blades are installed in both cylindrical structures inside the rigid container, and the blades are configured as spiral structures.

[0014] Preferably, the blades are rotatably installed between the rigid container and the support cylinder. Both ends of the rigid container are fixedly installed with water turbines. One water turbine is connected between the oil inlet and its corresponding oil pump, and the other water turbine is connected between the oil outlet and its corresponding oil pump. The impellers in the water turbines are coaxially arranged with the rigid container, and the impellers in the two water turbines are respectively fixedly connected to the blades in the two cylindrical structures inside the rigid container.

[0015] Preferably, a hydraulic gauge is connected between the oil inlet and its corresponding oil pump, and a hydraulic gauge is also connected between the oil outlet and its corresponding oil pump.

[0016] Preferably, an adjustment mechanism is provided below the bracket, and the adjustment mechanism includes a base, a connecting seat is rotatably connected to the base, an adjustment plate is hinged to one side of the connecting seat, a guide rail parallel to the adjustment plate is fixedly installed on the other side of the connecting seat, a slide table is slidably connected to the guide rail, a connecting rod is hinged between the slide table and the adjustment plate, and fasteners are installed on the slide table.

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

[0018] 1. In this invention, a circulating oil circuit system is connected to the oil inlet and outlet, and an electric heating unit is used in the oil tank to achieve precise and stable control of the circulating oil temperature. This helps to ensure uniform and efficient heat transfer within the container cavity, thereby creating a highly uniform and stable temperature field outside the flexible membrane wrapping the sample. At the same time, by setting a rubber layer to isolate the conductive oil from the external circulating oil, the resistivity imaging monitoring inside the rubber layer using electrodes is not affected by the external oil circulation. With these combined features, the problems of distortion in the simulation of the internal temperature field of the sample and slow control response under high confining pressure conditions in traditional devices are effectively solved, greatly improving the simulation realism of the heat-water-force interaction during the THMC coupling process.

[0019] 2. In this invention, by fixing the insulating cylinder between the flexible membrane and the rubber layer, and immersing the electrode plates uniformly distributed on its inner wall in static conductive oil, a stable and non-invasive electrical coupling is formed between the electrode plates and the sample through the flexible membrane and the conductive oil. During the test, the spatial distribution, morphological evolution and saturation change of the bentonite hydration intrusion front in the precast crack of granite can be continuously and in situ monitored by resistivity imaging technology to obtain dynamic image data. This overcomes the damage to the integrity of the sample caused by traditional final sampling or invasive sensor monitoring, and is conducive to realizing non-destructive visualization observation of key sealing processes.

[0020] 3. In this invention, the simulated solution is preheated by a water tank placed inside the oil tank and immersed in hot oil. This ensures that the temperature of the aqueous solution injected into the granite fissures by the constant flow pump quickly reaches the same level as the overall temperature field of the sample. This avoids the instantaneous interference caused by the injection of cold fluid to the local temperature field and the hydration reaction rate of bentonite. This ensures the accuracy of the simulation of the coupling effect between the seepage field and the temperature field, making the experimental conditions closer to the real state of groundwater in deep geological treatment reservoirs after being affected by decay heat. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 This is a perspective view of the present invention;

[0023] Figure 2 This is a top view of the present invention;

[0024] Figure 3 For the present invention Figure 2 Sectional view at point AA;

[0025] Figure 4 This is a perspective view of the rigid container and opening / closing mechanism of the present invention;

[0026] Figure 5 This is a perspective view of the rigid container of the present invention;

[0027] Figure 6 This is an exploded view of the internal structure of the rigid container of the present invention;

[0028] Figure 7 This is a top view of the rigid container of the present invention;

[0029] Figure 8 For the present invention Figure 7 Sectional view at point BB;

[0030] Figure 9 For the present invention Figure 7 Sectional view at CC;

[0031] Figure 10 For the present invention Figure 7 Sectional view at point DD.

[0032] In the picture:

[0033] 1. Rigid container; 11. Flexible membrane; 12. Rubber layer; 13. Insulating cylinder; 14. Electrode plate; 15. Support cylinder; 16. Oil inlet; 17. Oil outlet; 18. Water injection pipe;

[0034] 2. Opening; 21. Connecting pipe;

[0035] 3. Blades; 31. Water turbine;

[0036] 4. Hydraulic gauge;

[0037] 5. Bracket; 51. Slide rail; 52. Hydraulic push rod;

[0038] 6. Base; 61. Connecting seat; 62. Adjusting plate; 63. Guide rail; 64. Slide table; 65. Connecting rod; 66. Fastener;

[0039] 7. Granite sample; 71. Precast crack; 72. Bentonite sample. Detailed Implementation

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0041] Example: This example provides a test apparatus for simulating bentonite hydration intrusion into a single fracture in granite. See [link to example]. Figure 1 - Figure 10 Specifically, it includes a rigid container 1, inside which a flexible membrane 11 and a rubber layer 12 are arranged sequentially from the inside to the outside. Conductive oil is filled between the flexible membrane 11 and the rubber layer 12. An insulating cylinder 13 is fixedly installed between the flexible membrane 11 and the rubber layer 12, and the end wall of the insulating cylinder 13 is set with a hollow structure. Electrode plates 14 are fixedly installed on the inner wall of the insulating cylinder 13. An oil inlet 16 and an oil outlet 17 are fixedly connected to the outer end walls of both ends of the rigid container 1, respectively. Both the oil inlet 16 and the oil outlet 17 are externally connected to an oil pump, and the oil pump is externally connected to an oil tank. An electric heating unit is installed in the oil tank. A water injection pipe 18 connected to the interior of the flexible membrane 11 is fixedly installed at the center of one end of the rigid container 1. The water injection pipe 18 is externally connected to a constant flow pump.

[0042] The rigid container 1 has an opening 2 in the middle, and the opening 2 has a stepped structure. The rigid container 1 is divided into two cylindrical structures from the opening 2. The two cylindrical structures are connected by a connecting pipe 21. An opening and closing mechanism is provided on the outside of the rigid container 1. The opening and closing mechanism includes a bracket 5. The cylindrical structure on one side of the rigid container 1 is fixedly connected to the bracket 5. A slide rail 51 and a hydraulic push rod 52 arranged parallel to the slide rail 51 are fixedly installed on the bracket 5. The cylindrical structure on the other side of the rigid container 1 is slidably connected to the slide rail 51 and fixedly connected to the piston rod of the hydraulic push rod 52.

[0043] The flexible membrane 11 contains a granite sample 7, and a prefabricated crack 71 is formed inside the granite sample 7 to connect with the water injection pipe 18. The side of the flexible membrane 11 away from the water injection pipe 18 contains a bentonite sample 72 that is tightly attached to the granite sample 7.

[0044] When the device is in use, the hydraulic push rod 52 can be activated. With the smooth contraction of the hydraulic push rod 52, the slidable half-cylindrical structure is pulled to move along the slide rail 51, thereby opening the stepped opening 2 to facilitate the handling of samples.

[0045] During the simulation test, the staff placed a granite sample 7 with pre-fabricated cracks 71 inside a cylindrical structure on one side of the rigid container 1, and a high-compacted bentonite sample 72 inside the cylindrical structure on the other side of the rigid container 1. A flexible membrane 11 was used to uniformly wrap and seal the granite sample 7 and the bentonite sample 72, and to ensure that the water injection pipe 18 was connected to the pre-fabricated cracks 71. Then, the opening and closing mechanism was used to ensure the tight sealing of the rigid container 1, so that the mating surfaces of the granite sample 7 and the bentonite sample 72 were precisely aligned. By setting the opening 2 as a stepped structure, the structural complexity after the opening 2 is closed can be effectively increased, thereby effectively improving the sealing performance of the two cylindrical structures inside the rigid container 1 after closure.

[0046] With the rigid container 1 closed, the sample assembly consisting of granite sample 7 and bentonite sample 72 is located in the center of the insulating cylinder 13. The electrode plate array 14 on the inner wall of the insulating cylinder 13 surrounds the outer side of the granite sample 7. Then, the operator starts the oil circuit system connecting the oil inlet 16 and the oil outlet 17 and the electric heating unit in the oil tank. The oil pump pumps the oil heated to the target temperature into the rigid container 1 from the oil inlet 16, filling the cavity between the inner wall of the rigid container 1 and the rubber layer 12, and then flows back to the oil tank from the oil outlet 17, forming a circulating flow of oil.

[0047] During this process, the system controls the output pressure of the oil pump through servo control to adjust the flow rate of oil inlet 16 and outlet 17, so that the oil pressure in the cavity can be rapidly increased and stabilized at the preset high confining pressure value. Under the flexible conduction of conductive oil between the flexible membrane 11 and the rubber layer 12, a geostress environment simulation with uniform force can be formed around the sample assembly. At the same time, the circulating oil is used as a heat transfer medium to continuously and uniformly transfer heat to the internal rubber layer 12, flexible membrane 11 and sample assembly, and build a stable high temperature field around the sample assembly.

[0048] Then, the constant flow pump is started, and the simulated solution is injected into the pre-fabricated crack 71 in the granite sample 7 through the water injection pipe 18 at a constant flow rate, which officially triggers the hydration and intrusion process of bentonite. After the simulated solution comes into contact with the bentonite sample 72, the bentonite sample 72 undergoes a hydration reaction, which causes the bentonite sample 72 to begin to expand. Under the action of the expansion force, it intrudes into the pre-fabricated crack 71 in the opposite direction. During this process, the electrode sheet 14 is electrically coupled to the sample through the static conductive oil around it. The external resistivity imaging system continuously excites and measures in real time, realizing in-situ, dynamic, and non-destructive imaging monitoring of fluid transport and bentonite intrusion morphology in the crack.

[0049] When in use, this device simultaneously achieves two core functions—applying high confining pressure and constructing a uniform temperature field—through an integrated oil pressure-oil temperature circulation system. The control of temperature and pressure is independent and precise, effectively simulating the stress and temperature fields in deep geological environments. This effectively solves the problem of incompatibility between high confining pressure and precise uniform heating in traditional methods. Through the circulation of oil, the heat exchange efficiency and the uniformity and stability of the temperature field are greatly improved, ensuring that the sample is in a realistic physical environment with well-defined boundary conditions and high controllability throughout the entire THMC coupling process. This lays a solid foundation for obtaining reliable experimental data. At the same time, the non-invasive electrode arrangement ensures the authenticity of the mechanical and hydraulic responses of the sample, enabling high-fidelity visualization observation of the sealing core process.

[0050] In the specific implementation process, a water tank immersed in the oil is fixedly installed inside the oil tank, and the water tank stores the simulated solution. The constant flow pump is connected to the water tank. When the device is in use, the electric heating unit first heats the oil in the oil tank to the target temperature. The heat of the oil continuously heats and preheats the simulated solution inside through the water tank wall. When the constant flow pump is started, the preheated simulated solution is injected into the prefabricated crack 71 in the granite sample 7 through the water injection pipe 18. The above structure setting realizes the active matching and rapid balance between the temperature of the injected simulated solution and the temperature field of the confining pressure oil. It can eliminate the local thermal disturbance caused by cold injection, which is conducive to ensuring the accuracy of the seepage-temperature coupling boundary conditions. It ensures that the hydration reaction of bentonite always takes place in the preset temperature environment, which significantly improves the consistency of experimental data.

[0051] In the specific implementation process, such as Figure 6 and Figure 8 - Figure 10 As shown, a support cylinder 15 is fixedly installed inside the rigid container 1, which is sleeved on the outside of the rubber layer 12. The end wall of the support cylinder 15 is set with a hollow structure. When the device is in use, the hollow structure on the end wall of the support cylinder 15 facilitates the smooth flow of oil inside and outside. Before loading the sample or when changing the sample, the flow rate of the oil pump connected to the oil outlet 17 can be increased. Under the suction effect, the oil flowing out of the rigid container 1 at high speed generates a local negative pressure in the annular flow channel between the support cylinder 15 and the rubber layer 12, which drives the flexible rubber layer 12 and the inner flexible membrane 11 to stick tightly to the inner wall of the support cylinder 15. This temporarily expands the internal cavity wrapped by the flexible membrane 11, which greatly facilitates the smooth loading and precise positioning of the precisely sized granite sample 7 and bentonite sample 72, effectively reduces the assembly difficulty, and avoids damage to the sample or flexible membrane 11 caused by hard insertion.

[0052] In the specific implementation process, such as Figure 8 and Figure 9As shown, the two cylindrical structures have the same depth. The length of granite sample 7 is greater than the depth of a single cylindrical structure, while the length of bentonite sample 72 is less than the depth of a single cylindrical structure. The mating surfaces of granite sample 7 and bentonite sample 72 are misaligned with the opening 2. During assembly, the longer granite sample 7 passes through and is sealed in both cylindrical structures, becoming a bridge and load-bearing skeleton connecting the two parts. The shorter bentonite sample 72 is completely contained in one of the cylindrical structures and is tightly fitted to one end of granite sample 7. During the test, the entire sample assembly is subjected to confining pressure as a whole.

[0053] With the above structural design, after the rigid container 1 is closed, the contact surface between the granite sample 7 and the bentonite sample 72 is completely sealed in an integral cylindrical cavity, preventing the contact surface from facing the openable opening 2. This ensures that during the entire main experimental stage under high confining pressure, the contact surface area is provided with uniform mechanical constraint by the continuous cylindrical wall, and its stress state is not affected by any structural discontinuities or potential micro-leakage that may exist at the opening 2, thereby ensuring the authenticity and reliability of the stress and sealing environment of the core interface.

[0054] In the specific implementation process, such as Figure 6 , Figure 8 and Figure 10 As shown, blades 3 are installed in both cylindrical structures inside the rigid container 1, which are sleeved on the outside of the support cylinder 15. The blades 3 are spiral structures and are rotatably installed between the rigid container 1 and the support cylinder 15. Water turbines 31 are fixedly installed at both ends of the rigid container 1. One water turbine 31 is connected between the oil inlet 16 and its corresponding oil pump, and the other water turbine 31 is connected between the oil outlet 17 and its corresponding oil pump. The impellers in the water turbines 31 are coaxially arranged with the rigid container 1. The impellers in the two water turbines 31 are fixedly connected to the blades 3 in the two cylindrical structures inside the rigid container 1, respectively.

[0055] In this device, when the oil circulation system is working, the flowing oil drives the impeller of the water turbine 31 to rotate, which in turn drives the spiral blade 3 connected to it to rotate slowly in the annular flow channel. The rotation of the spiral blade 3 can generate a continuous stirring and guiding effect on the oil, breaking the thermal stratification phenomenon that may be caused by temperature difference, ensuring the uniformity of oil temperature in the entire container cavity, and further improving the heat transfer efficiency and temperature field stability. In order to ensure the stability of the simulated solution injection, the water injection pipe 18 moves through the center of the impeller in the water turbine 31 on one side.

[0056] In the specific implementation process, such as Figure 1 , Figure 4 and Figure 5As shown, a hydraulic gauge 4 is connected between the oil inlet 16 and its corresponding oil pump, and a hydraulic gauge 4 is also connected between the oil outlet 17 and its corresponding oil pump. During the test, the readings of the two hydraulic gauges 4 are continuously monitored. The two hydraulic gauges 4 indicate the oil pressure on the inlet side and the outlet side, respectively. When the bentonite sample 72 absorbs water and expands, it exerts a thrust on the granite sample 7. The change in the stress state of the bonding surface will cause slight deformation of the flexible constraints on both sides. With the help of the conductive oil, the hydraulic pressure of the oil between the rigid container 1 and the rubber layer 12 will change slightly. By comparing and analyzing the pressure difference and dynamic changes of the two hydraulic gauges 4, the magnitude and evolution trend of the expansion pressure on the bonding surface of granite and bentonite can be indirectly and continuously estimated, providing important auxiliary data for quantitatively evaluating the mechanical performance of the self-sealing effect.

[0057] In the specific implementation process, such as Figure 1 - Figure 3 As shown, an adjustment mechanism is provided below the bracket 5, and the adjustment mechanism includes a base 6. A connecting seat 61 is rotatably connected to the base 6. An adjustment plate 62 is hinged to one side of the connecting seat 61. A guide rail 63 parallel to the adjustment plate 62 is fixedly installed on the other side of the connecting seat 61. A slide table 64 is slidably connected to the guide rail 63. A connecting rod 65 is hinged between the slide table 64 and the adjustment plate 62. Fasteners 66 are installed on the slide table 64.

[0058] When using this device, the position of the rigid container 1 can be flexibly changed by adjusting the rotation of the connecting seat 61 and the tilt angle of the adjusting plate 62. During the adjustment process, the fastener 66 is loosened, the slide 64 is driven to move along the guide rail 63, and the adjusting plate 62 is driven to rotate around the hinge point through the connecting rod 65 mechanism, thereby changing the tilt angle of the entire support 5 and the rigid container 1 fixed on it. After the adjustment is in place, the fastener 66 is locked. At the same time, the orientation of the rigid container 1 can be adjusted by rotating the connecting seat 61. When the device is used upside down, the entire experimental device can flexibly simulate the working conditions of granite cracks in different spatial orientations, which is convenient for studying the influence of gravity direction on bentonite intrusion behavior, and greatly expands the simulation range and scientific research value of the device.

[0059] Specifically, the working principle of this invention is as follows:

[0060] When using the device, a granite sample 7 with pre-fabricated fissures 71 and a high-compacted bentonite sample 72 are tightly bonded together and wrapped in a flexible membrane 11. The oil circulation system and electric heating unit are activated, and the oil inside the rigid container 1 is pressurized and circulated for heating through the oil inlet 16 and oil outlet 17, thereby establishing a stable high confining pressure and uniform temperature field around the sample assembly to simulate deep geological stress and decay thermal environment. Subsequently, a constant flow pump is activated to inject the simulated solution preheated in the oil tank into the pre-fabricated fissures 71 of the granite through the water injection pipe 18 at a uniform speed. The solution moves in the fissures and contacts the bentonite sample 72, causing it to hydrate and expand. During this process, the electrode array 14 integrated on the insulating cylinder 13 continuously scans the sample assembly using resistivity imaging technology through the coupling of static conductive oil, and obtains images of the fluid distribution in the fissures and the changes in the electrical properties of the bentonite intrusion in real time, realizing non-destructive visual monitoring of the intrusion process. At the same time, the differential pressure monitoring of the hydraulic gauge 4 helps to reflect the pressure changes of the bonding surface.

[0061] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A test apparatus for simulating bentonite hydration intrusion into a single fracture in granite, comprising a rigid container (1), characterized in that: The rigid container (1) has a flexible membrane (11) and a rubber layer (12) arranged sequentially from the inside to the outside. Conductive oil is filled between the flexible membrane (11) and the rubber layer (12). An insulating cylinder (13) is fixedly installed between the flexible membrane (11) and the rubber layer (12), and the end wall of the insulating cylinder (13) is set with a hollow structure. Electrode plates (14) are fixedly installed on the inner wall of the insulating cylinder (13). An oil inlet (16) and an oil outlet (17) are fixedly connected to the outer end walls of both ends of the rigid container (1), respectively. The oil inlet (16) Both the oil outlet (17) and the oil pump are connected to an external oil tank. An electric heating unit is installed in the oil tank. A water injection pipe (18) connected to the interior of the flexible membrane (11) is fixedly installed at the center of one end of the rigid container (1). A constant flow pump is connected to the water injection pipe (18). A granite sample (7) is wrapped inside the flexible membrane (11). A prefabricated crack (71) is formed inside the granite sample (7) to connect with the water injection pipe (18). A bentonite sample (72) that is tightly attached to the granite sample (7) is wrapped on the side of the flexible membrane (11) away from the water injection pipe (18).

2. The experimental apparatus for simulating bentonite hydration intrusion into a single fracture of granite according to claim 1, characterized in that: The oil tank contains a water tank that is immersed in the oil and stores a simulated solution. The constant flow pump is connected to the water tank.

3. The experimental apparatus for simulating bentonite hydration intrusion into granite with a single fracture, as described in claim 1, is characterized in that: The rigid container (1) is fixedly installed with a support cylinder (15) sleeved on the outside of the rubber layer (12), and the end wall of the support cylinder (15) is set as a hollow structure.

4. The test apparatus for simulating bentonite hydration intrusion into a single fracture of granite according to claim 1, characterized in that: The rigid container (1) has an opening (2) in the middle, and the opening (2) has a stepped structure. The rigid container (1) has an opening and closing mechanism on the outside.

5. The test apparatus for simulating bentonite hydration intrusion into a single fracture of granite according to claim 4, characterized in that: The rigid container (1) is divided into two cylindrical structures from the opening (2). A connecting pipe (21) connects the two cylindrical structures. The two cylindrical structures have the same depth. The length of the granite sample (7) is greater than the depth of a single cylindrical structure. The length of the bentonite sample (72) is less than the depth of a single cylindrical structure. The mating surfaces of the granite sample (7) and the bentonite sample (72) are misaligned with the opening (2).

6. The experimental apparatus for simulating bentonite hydration intrusion into granite with a single fracture, as described in claim 5, is characterized in that: The opening and closing mechanism includes a bracket (5), a cylindrical structure on one side of the rigid container (1) is fixedly connected to the bracket (5), a slide rail (51) is fixedly installed on the bracket (5), and a hydraulic push rod (52) is arranged parallel to the slide rail (51). The cylindrical structure on the other side of the rigid container (1) is slidably connected to the slide rail (51) and fixedly connected to the piston rod of the hydraulic push rod (52).

7. The experimental apparatus for simulating bentonite hydration intrusion into a single fracture of granite according to claim 3, characterized in that: The rigid container (1) has blades (3) installed in both cylindrical structures on the outside of the support cylinder (15), and the blades (3) are set in a spiral structure.

8. The experimental apparatus for simulating bentonite hydration intrusion into a single fracture of granite according to claim 7, characterized in that: The blade (3) is rotatably installed between the rigid container (1) and the support cylinder (15). Both ends of the rigid container (1) are fixedly installed with water turbines (31). One of the water turbines (31) is connected between the oil inlet (16) and its corresponding oil pump, and the other water turbine (31) is connected between the oil outlet (17) and its corresponding oil pump. The impeller in the water turbine (31) is coaxially arranged with the rigid container (1). The impellers in the two water turbines (31) are respectively fixedly connected to the blades (3) in the two cylindrical structures in the rigid container (1).

9. The experimental apparatus for simulating bentonite hydration intrusion into a single fracture of granite according to claim 2, characterized in that: A hydraulic gauge (4) is connected between the oil inlet (16) and its corresponding oil pump, and a hydraulic gauge (4) is also connected between the oil outlet (17) and its corresponding oil pump.

10. The experimental apparatus for simulating bentonite hydration intrusion into a single fracture of granite according to claim 6, characterized in that: An adjustment mechanism is provided below the bracket (5), and the adjustment mechanism includes a base (6). A connecting seat (61) is rotatably connected to the base (6). An adjustment plate (62) is hinged to one side of the connecting seat (61). A guide rail (63) parallel to the adjustment plate (62) is fixedly installed on the other side of the connecting seat (61). A slide table (64) is slidably connected to the guide rail (63). A connecting rod (65) is hinged between the slide table (64) and the adjustment plate (62). Fasteners (66) are installed on the slide table (64).

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