A temperature-controlled multi-directional complex disturbance true triaxial shear-permeability test system

Abstract

The application discloses a temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system, which comprises a pressure cabin, a shear box, a pressure applying assembly and a temperature control device. The shear box is arranged in the pressure cabin, and the shear box comprises an upper shear box and a lower shear box. The upper shear box and the lower shear box are different in the force acting on a rock sample. The pressure applying assembly comprises a first pressure head and a second pressure head. The first pressure head and the second pressure head apply the force along a first direction and drive the upper shear box and the lower shear box to approach each other. The temperature control device comprises a heat exchange coil and a temperature control compensation system. The heat exchange coil surrounds the shear box. The temperature control compensation system is used for outputting a heat transfer medium to the heat exchange coil. While the shear force is applied to the rock sample by the pressure applying assembly and the shear box, the temperature control device precisely controls the peripheral temperature of the rock sample, and then the fault interface shear mechanical behavior under different temperatures is simulated.

Description

Technical Field

[0001] This invention relates to the field of underground engineering technology, and in particular to a temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system. Background Technology

[0002] In deep energy development and major underground engineering projects, the media found in geological faults are often in complex thermodynamic environments, and their shear-seepage characteristics have a decisive impact on engineering safety and efficiency. Therefore, conducting simulations to obtain relevant data for such complex geological conditions can provide theoretical support for the safe and efficient development of underground resources in the future.

[0003] Both types of geological formations—ice-rock mixed faults beneath high-altitude glaciers and artificial faults in high-temperature geothermal reservoirs within deep geological layers—exhibit significant shear zones due to temperature control effects. In the former, ice cementation and frictional heating dominate the strength evolution and instability mechanism of the interface; in the latter, temperature changes induced by cyclic injection and production directly affect the conductivity and long-term stability of the fracture network. Together, these phenomena reveal that temperature is not only a boundary condition but also a core intrinsic variable driving the evolution of fault mechanics-hydraulic coupling behavior.

[0004] However, existing conventional triaxial systems cannot accurately reproduce the dynamic coupling process of temperature and stress-seepage in these two types of engineering projects. Therefore, it is necessary to overcome the limitations of traditional experimental methods and reveal the regulation mechanism of temperature on the shear mechanical behavior and seepage characteristics of fault interfaces in a temperature range of several hundred degrees Celsius from below freezing point to above zero. This has important theoretical value and practical significance for ensuring the stability of engineering projects in high-altitude and cold regions and optimizing the efficiency of geothermal extraction. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, this application proposes a temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system, which can simulate the shear mechanical behavior of fault interfaces at different temperatures.

[0006] This application also proposes a control method for the above-mentioned temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system.

[0007] According to a first aspect embodiment of this application, a temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system includes: Pressure chamber, which has a sealed space inside; A shear box is disposed within the sealed space. The shear box includes an upper shear box and a lower shear box. The upper and lower shear boxes enclose a space capable of accommodating a rock sample. The inner sidewall of the upper shear box is provided with a first force-bearing block that can contact the rock sample, and the inner sidewall of the lower shear box is provided with a second force-bearing block that can contact the rock sample. The projections of the first and second force-bearing blocks in a first direction do not coincide. The pressure application assembly includes a first pressure head and a second pressure head, both of which apply force along a first direction and drive the upper shear box and the lower shear box to move closer to each other. A temperature control device includes a heat exchange coil and a temperature control compensation system. The heat exchange coil is arranged around the shear box, and both ends of the heat exchange coil are respectively connected to the temperature control compensation system. The temperature control compensation system is used to output a heat transfer medium to the heat exchange coil, and the heat transfer medium transfers heat or cold to the rock sample through the heat exchange coil.

[0008] The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to the embodiments of this application has at least the following beneficial effects: while applying shear force to the rock sample through the pressure application component and the shear box, the surrounding temperature of the rock sample is precisely controlled by the temperature control device, thereby simulating the shear mechanical behavior of the fault interface at different temperatures.

[0009] According to some embodiments of this application, the bottom of the lower shear box is provided with rollers, the rollers are arranged perpendicular to the first direction, and the lower shear box can move along the first direction with the support of the rollers.

[0010] According to some embodiments of this application, the shear box further includes a limiting rod, and the upper shear box and the lower shear box are respectively provided with through holes through which the limiting rod can pass. The inner diameter of the through hole is larger than the outer diameter of the limiting rod, and the limiting rod extends along a second direction.

[0011] According to some embodiments of this application, the pressure application assembly further includes a third pressure head, which abuts against the upper shear box and applies a force to the upper shear box along a second direction.

[0012] According to some embodiments of this application, the pressure application assembly further includes a servo system, which is poweredly connected to the first pressure head, the second pressure head, and the third pressure head, and applies confining pressure to the shear box.

[0013] According to some embodiments of this application, the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system further includes a seepage system, which is connected to the rock sample through a seepage pipe, and the seepage system inputs liquid into the rock sample to simulate seepage.

[0014] According to some embodiments of this application, a pressure gauge and a flow meter are provided on the seepage pipe, wherein the pressure gauge is used to detect the seepage pressure and the flow meter is used to detect the seepage flow rate.

[0015] According to some embodiments of this application, the temperature control device further includes a temperature sensor disposed inside the pressure chamber and electrically connected to the temperature control compensation system.

[0016] The control method according to the second aspect of this application, which is applied to the above-mentioned temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system, includes the following steps: The rock sample is placed inside the upper shear box and the lower shear box; The pressure application assembly is activated, causing the first pressure head and the second pressure head to squeeze the shear box respectively; The first force-bearing block and the second force-bearing block apply forces of different axes to the rock sample, thereby applying shear force to the rock sample; The temperature control compensation system is activated, and the temperature control compensation system outputs the heat transfer medium to the heat exchange coil; The heat transfer medium transfers heat or cold to the rock sample during the flow of the heat exchange coil, thereby controlling the temperature. Maintain pressure and temperature, test the rock sample, and record the experimental data.

[0017] The control method according to the embodiments of this application has at least the following beneficial effects: by continuously outputting heat transfer medium to the heat exchange coil through the temperature control compensation system, the heat transfer medium can exchange heat with the rock sample, thereby heating or cooling the rock sample, simulating high-temperature or low-temperature rock strata in reality, and improving the simulation degree.

[0018] According to some embodiments of this application, the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system further includes a seepage system, and the pressure application component further includes a servo system; after the pressure application component is started, the seepage system continuously outputs seepage to the rock sample, and the servo system continuously applies confining pressure to the shear box.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] The accompanying drawings are used to provide a further understanding of the technical solutions disclosed in this application and form part of the specification. They are used together with the embodiments disclosed in this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions disclosed in this application.

[0021] Figure 1 This is a schematic diagram of the structure of the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to the first aspect of this application; Figure 2 This is a schematic diagram showing the connection of each component in the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to the first aspect of this application.

[0022] Reference numerals: 100-Pressure chamber, 200-Shear box, 210-Upper shear box, 211-First force-bearing block, 220-Lower shear box, 221-Second force-bearing block, 230-Roller, 240-Limit rod, 310-First pressure head, 320-Second pressure head, 330-Third pressure head, 340-Servo system, 350-Cooling system, 400-Temperature control device, 410-Heat exchange coil, 420-Temperature control compensation system, 430-Temperature sensor, 500-Seepage system, 510-Seepage pipe, 511-Pressure gauge, 512-Flow meter, 520-Wastewater pool, 600-Control system. Detailed Implementation

[0023] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0024] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0026] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0027] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] In deep energy development and major underground engineering projects, the media found in geological faults are often in complex thermodynamic environments, and their shear-seepage characteristics have a decisive impact on engineering safety and efficiency. Therefore, conducting simulations to obtain relevant data for such complex geological conditions can provide theoretical support for the safe and efficient development of underground resources in the future.

[0029] Both subglacial ice-rock mixed faults and deep geological high-temperature geothermal reservoir faults exhibit significant shear zones due to temperature control effects. In the former, ice cementation and frictional heating dominate the strength evolution and instability mechanism of the interface; in the latter, temperature changes induced by cyclic injection and production directly affect the conductivity and long-term stability of the fracture network. Together, these phenomena reveal that temperature is not only a boundary condition but also a core intrinsic variable driving the evolution of fault mechanical-hydraulic coupled behavior.

[0030] However, existing conventional triaxial systems cannot accurately reproduce the dynamic coupling process of temperature and stress-seepage in these two types of engineering projects. Therefore, it is necessary to overcome the limitations of traditional experimental methods and reveal the regulation mechanism of temperature on the shear mechanical behavior and seepage characteristics of fault interfaces in a temperature range of several hundred degrees Celsius from below freezing point to above zero. This has important theoretical value and practical significance for ensuring the stability of engineering projects in high-altitude and cold regions and optimizing the efficiency of geothermal extraction.

[0031] In response, this application proposes a temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system. While applying shear force to the rock sample through the pressure application component and shear box, the system precisely controls the surrounding temperature of the rock sample through a temperature control device, thereby simulating the shear mechanical behavior of the fault interface at different temperatures.

[0032] In addition, this application also proposes a control method for the above-mentioned temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system. The method continuously outputs heat transfer medium to the heat exchange coil through the temperature control compensation system, so that the heat transfer medium can exchange heat with the rock sample, raise or lower the temperature of the rock sample, simulate the high temperature or low temperature rock layer in reality, and improve the simulation degree.

[0033] Reference Figure 1 The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system in the first aspect of this application includes a pressure chamber 100, a shear box 200, a pressure application component, and a temperature control device 400. The pressure chamber 100 constitutes the main structure of this temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system. Its interior is sealed for mounting rock samples. The rock samples are subjected to shear force and confining pressure within the pressure chamber 100, thereby simulating the high pressure and fault interface shear mechanical behavior in deep geological environments. The shear box 200 is used to fix the rock samples and can convert the pressure from the pressure application component into shear force on the rock samples. The temperature control device 400 is used to transfer heat or cold to the rock samples, thereby simulating high-temperature or low-temperature environments and exploring the dynamic coupling process of temperature and stress-seepage.

[0034] Specifically, a sealed space is provided inside the pressure chamber 100 for housing the shear box 200. By providing a sealed space, the external environment can be prevented from affecting the temperature inside the pressure chamber 100; it also prevents seepage or leakage of the confining pressure fluid from the pressure chamber 100, which could lead to depressurization of the pressure chamber 100 and affect the simulation accuracy of the high-pressure environment.

[0035] The shear box 200 includes an upper shear box 210 and a lower shear box 220. The upper and lower shear boxes 210 and 220 enclose a space capable of accommodating a rock sample. When the upper and lower shear boxes 210 and 220 are brought close together under external force, the force between them can be transmitted to the rock sample, causing the rock sample to be compressed. It is worth noting that the inner wall of the upper shear box 210 is provided with a first force-bearing block 211 that can contact the rock sample, and the inner wall of the lower shear box 220 is provided with a second force-bearing block 221 that can contact the rock sample. The first and second force-bearing blocks 211 and 221 are connected in a first direction (referring to...). Figure 1 The projections of the first force block 211 onto the rock sample (in the x direction) do not coincide, thus the force exerted by the first force block 211 on the rock sample is not coaxial with the force exerted by the second force block 221 on the rock sample, forming a shear force.

[0036] The pressure application assembly includes a first pressure head 310 and a second pressure head 320. Both the first pressure head 310 and the second pressure head 320 apply force along a first direction and drive the upper shear box 210 and the lower shear box 220 closer to each other. The first pressure head 310 and the second pressure head 320 are hydraulically driven to ensure that they can apply a sufficiently large force to the rock sample to simulate the complex mechanical environment of deep geological formations in reality.

[0037] The temperature control device 400 includes a heat exchange coil 410 and a temperature compensation system 420. The heat exchange coil 410 is arranged around the shear box 200, and both ends of the heat exchange coil 410 are connected to the temperature compensation system 420. The temperature compensation system 420 outputs a heat transfer medium to the heat exchange coil 410, which transfers heat or cold to the rock sample through the heat exchange coil 410. The heat transfer medium returns to the temperature compensation system 420 after heat exchange, and the temperature compensation system 420 continues to exchange heat with the heat transfer medium to restore it to a predetermined temperature, and then outputs it to the heat exchange coil 410 for the next round of heat exchange. The ambient temperature of the rock sample is maintained through this cyclic heat exchange method. The heat transfer medium can be a gas or a liquid. The number of turns of the heat exchange coil 410 around the shear box 200 can be increased or decreased according to actual conditions.

[0038] Furthermore, a roller 230 is provided at the bottom of the lower shear box 220. The roller 230 is arranged perpendicular to the first direction. The lower shear box 220 can move along the first direction with the support of the roller 230. Thus, on the one hand, the lower shear box 220 is supported by the roller 230, and on the other hand, the lower shear box 220 can move slightly when subjected to the force of the first pressure head 310 or the second pressure head 320. This movement will not cause serious scraping to the bottom of the pressure chamber 100, reducing the damage to the experimental components during the experiment.

[0039] Furthermore, the shear box 200 also includes a limiting rod 240. The upper shear box 210 and the lower shear box 220 are respectively provided with through holes through which the limiting rod 240 can pass. The limiting rod 240 is along the second direction (refer to...). Figure 1 The limit rod 240 extends in the y-direction, thereby limiting the displacement distance of the upper shear box 210 and the lower shear box 220 in the first direction. It is easily understood that the inner diameter of the through hole in both the upper shear box 210 and the lower shear box 220 is larger than the outer diameter of the limit rod 240, thus preventing the limit rod 240 from directly interfering with the movement of the upper shear box 210 and the lower shear box 220 during pressure application.

[0040] Furthermore, the pressure application assembly also includes a third pressure head 330, which abuts against the upper shear box 210. The third pressure head 330 applies force to the upper shear box 210 along the second direction. On the one hand, it can apply pressure to the rock sample in the second direction, and on the other hand, it can prevent the upper shear box 210 from moving along the second direction, thus limiting the upper shear box 210.

[0041] Furthermore, referring to Figure 2 The pressure application assembly also includes a servo system 340, which is poweredly connected to the first pressure head 310, the second pressure head 320, and the third pressure head 330, and is used to control the magnitude of the force applied by each pressure head. Simultaneously, the servo system 340 can apply confining pressure to the shear box 200, specifically by injecting confining pressure dynamic fluid into the pressure chamber 100 to increase the pressure within the pressure chamber 100.

[0042] Furthermore, since the servo system 340 generates a large amount of heat during operation, the pressure application assembly also includes a cooling system 350, which is connected to the servo system 340 to cool the servo system.

[0043] Furthermore, the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system also includes a seepage system 500, which is connected to the rock sample through a seepage pipe 510. The seepage system 500 inputs liquid into the rock sample through the seepage pipe 510 to simulate seepage, thereby improving the simulation accuracy of complex seepage conditions in real deep rock strata.

[0044] Furthermore, the seepage system 500 also includes a wastewater pool 520, where the seepage flowing from the rock sample can be collected.

[0045] Furthermore, a pressure gauge 511 and a flow meter 512 are installed on the seepage pipe 510. The pressure gauge 511 is used to detect the seepage pressure, and the flow meter 512 is used to detect the seepage flow rate, thereby enabling precise control of the seepage output.

[0046] Furthermore, the temperature control device 400 also includes a temperature sensor 430, which is installed inside the pressure chamber 100 and is electrically connected to the temperature control compensation system 420, thereby enabling closed-loop control of the temperature control compensation system 420.

[0047] Furthermore, the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system also includes a control system 600, which is electrically connected to each component in the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system to play a monitoring role and feed back the parameters during the experiment to an external control terminal for easy access by the user.

[0048] A control method for the above-mentioned temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system, according to a second aspect embodiment of this application, includes the following steps: S100. Place the rock sample into the upper shear box 210 and the lower shear box 220; S200. Start the pressure application assembly and servo system 340. On the one hand, the servo system 340 continuously applies confining pressure to the shear box 200. On the other hand, the first pressure head 310, the second pressure head 320 and the third pressure head 330 in the pressure application assembly squeeze the shear box 200 respectively. The first pressure head 310 and the second pressure head 320 together generate shearing force on the shear box 200, and the third pressure head 330 generates normal pressure on the shear box 200. S300. The first force-bearing block 211 and the second force-bearing block 221 apply forces with different axes to the rock sample, thereby applying shear force to the rock sample; S400. Start the temperature control compensation system 420, and the temperature control compensation system 420 outputs heat transfer medium to the heat exchange coil 410; S500. During the flow of the heat transfer medium in the heat exchange coil 410, heat or cold is transferred to the rock sample, thereby controlling the temperature. S600. Maintain pressure and temperature, test the rock sample, and record the experimental data.

[0049] Furthermore, in some embodiments, the temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system also includes a seepage system 500. After the pressure application components are activated, the seepage system 500 continuously outputs seepage to the rock sample to simulate complex seepage conditions and high-pressure environments in real deep rock formations.

[0050] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A temperature-controlled, multi-directional complex disturbance true triaxial shear-seepage test system, characterized in that, include: Pressure chamber, which has a sealed space inside; A shear box is disposed within the sealed space. The shear box includes an upper shear box and a lower shear box. The upper and lower shear boxes enclose a space capable of accommodating a rock sample. The inner sidewall of the upper shear box is provided with a first force-bearing block that can contact the rock sample, and the inner sidewall of the lower shear box is provided with a second force-bearing block that can contact the rock sample. The projections of the first and second force-bearing blocks in a first direction do not coincide. The pressure application assembly includes a first pressure head and a second pressure head, both of which apply force along a first direction and drive the upper shear box and the lower shear box to move closer to each other. A temperature control device includes a heat exchange coil and a temperature control compensation system. The heat exchange coil is arranged around the shear box, and both ends of the heat exchange coil are respectively connected to the temperature control compensation system. The temperature control compensation system is used to output a heat transfer medium to the heat exchange coil, and the heat transfer medium transfers heat or cold to the rock sample through the heat exchange coil.

2. The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to claim 1, characterized in that: The bottom of the lower shear box is provided with rollers, which are arranged perpendicular to the first direction, and the lower shear box can move along the first direction with the support of the rollers.

3. The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to claim 1, characterized in that: The shearing box also includes a limiting rod. The upper shearing box and the lower shearing box are respectively provided with through holes that allow the limiting rod to pass through. The inner diameter of the through hole is larger than the outer diameter of the limiting rod, and the limiting rod extends along a second direction.

4. The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to claim 3, characterized in that: The pressure application assembly also includes a third pressure head, which abuts against the upper shear box and applies a force to the upper shear box along a second direction.

5. The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to claim 4, characterized in that: The pressure application component also includes a servo system, which is poweredly connected to the first pressure head, the second pressure head, and the third pressure head, and applies confining pressure to the shear box.

6. The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to claim 1, characterized in that: The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system also includes a seepage system, which is connected to the rock sample through a seepage pipe. The seepage system inputs liquid into the rock sample to simulate seepage.

7. The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to claim 6, characterized in that: The seepage pipe is equipped with a pressure gauge and a flow meter. The pressure gauge is used to detect the seepage pressure, and the flow meter is used to detect the seepage flow rate.

8. The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system according to claim 1, characterized in that: The temperature control device also includes a temperature sensor, which is installed inside the pressure chamber and is electrically connected to the temperature control compensation system.

9. A control method for a temperature-controlled, multi-directional complex disturbance true triaxial shear-seepage test system according to any one of claims 1 to 8, characterized in that, include: The rock sample is placed inside the upper shear box and the lower shear box; The pressure application assembly is activated, causing the first pressure head and the second pressure head to squeeze the shear box respectively; The first force-bearing block and the second force-bearing block apply forces of different axes to the rock sample, thereby applying shear force to the rock sample; The temperature control compensation system is activated, and the temperature control compensation system outputs the heat transfer medium to the heat exchange coil; The heat transfer medium transfers heat or cold to the rock sample during the flow of the heat exchange coil, thereby controlling the temperature. Maintain pressure and temperature, test the rock sample, and record the experimental data.

10. The control method according to claim 9, characterized in that: The temperature-controlled multi-directional complex disturbance true triaxial shear-seepage test system also includes a seepage system, and the pressure application component also includes a servo system; after the pressure application component is started, the seepage system continuously outputs seepage to the rock sample, and the servo system continuously applies confining pressure to the shear box.

Images