Temperature-compensated seepage-shear coupled true triaxial test device and control method

Abstract

This invention discloses a temperature-compensated seepage-shear coupling true triaxial testing apparatus and control method. The apparatus includes a pressure chamber, a shear box, a temperature control system, a pressure application system, and a temperature-displacement corrector. The shear box is housed within the pressure chamber. The temperature control system includes a heat transfer jacket, multi-point thermometers, and a temperature controller. The heat transfer jacket is fitted over the shear box, and the multi-point thermometers are located within the cavity. The pressure application system includes a confining pressure loading device, a pressure head, and a pressure controller. The confining pressure loading device injects a confining pressure medium into the pressure chamber, and the pressure head applies a force to the shear box. The temperature-displacement corrector is electrically connected to the temperature control system and the pressure application system. This apparatus features a temperature control system to precisely regulate the temperature during the test, thereby simulating deep environments at different temperatures. Furthermore, the temperature-displacement corrector dynamically corrects the force applied by the pressure application system, reducing additional forces caused by thermal expansion or contraction and improving stress control accuracy.

Description

Technical Field

[0001] This invention relates to the field of deep geological experimental technology, and in particular to a temperature-compensated seepage-shear coupling true triaxial test device and control method. Background Technology

[0002] Deep underground engineering rock and soil masses are typically situated in complex environments characterized by high ground stress, high osmotic pressure, high temperature, and dynamic disturbance. Under these "three highs and one disturbance" conditions, the mechanical properties and seepage patterns of the rock and soil masses undergo significant changes. Research on the characteristics of these deep rock and soil masses is of high reference value for deep resource development engineering. In deep environments, rock and soil masses are not only subjected to complex mechanical compression but also to high temperature and high pressure. Temperature directly affects the elastic modulus, shear strength, and Poisson's ratio, and indirectly influences the seepage behavior of the rock and soil masses by altering the viscosity of the seepage medium and the seepage path, thereby affecting the stability of deep rock masses.

[0003] Existing true triaxial test apparatuses for seepage-shear coupling can simulate the stress conditions of soil and rock masses in deep environments, but they still have shortcomings in temperature control. Single heating or cooling methods can easily lead to large temperature differences between the core and surface of the sample, resulting in insufficient temperature field uniformity and making it difficult to realistically reproduce the multi-field coupling state of deep soil and rock masses. Moreover, soil and rock samples will expand or contract at different temperatures, which indirectly affects the magnitude of the normal or shear force applied to the soil and rock samples, leading to inaccurate experimental data.

[0004] Therefore, current seepage shear test models for deep underground rock and soil still require precise temperature control to simulate the changes in rock and soil at different temperatures. At the same time, mechanical corrections are needed for the thermal expansion and contraction of rock and soil samples to improve the accuracy of experimental data. 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-compensated seepage-shear coupling true triaxial testing device, which can simulate the changes in soil and rock mass at different temperatures, and can adjust the output of the force application mechanism according to the volume changes of the soil and rock mass sample at different temperatures, thereby correcting the influence of thermal expansion and contraction of the soil and rock mass sample on the stress.

[0006] This application also proposes a control method for the above-mentioned temperature-compensated seepage-shear coupling true triaxial test apparatus.

[0007] A temperature-compensated seepage-shear coupled true triaxial testing apparatus according to a first aspect embodiment of this application includes: Pressure chamber; A shear box is disposed in the pressure chamber, and a cavity for mounting the soil and rock sample is formed inside the shear box. A temperature control system includes a heat transfer jacket, a multi-point thermometer, and a temperature controller. The heat transfer jacket is fitted over the outside of the shear box, and the multi-point thermometer is connected to the shear box and disposed in the cavity. Both the heat transfer jacket and the multi-point thermometer are electrically connected to the temperature controller. The pressure application system includes a confining pressure loading device, a pressure head, and a pressure controller. The confining pressure loading device is used to inject a confining pressure medium into the pressure chamber, and the pressure head applies a force to the shear box. Both the loading device and the pressure head are poweredly connected to the pressure controller. A temperature-displacement corrector is electrically connected to the temperature control system and the pressure application system, and corrects the force applied by the pressure application system based on the temperature measurement results of the temperature control system.

[0008] The temperature-compensated seepage-shear coupling true triaxial testing device according to the embodiments of this application has at least the following beneficial effects: the testing device is equipped with a temperature control system to accurately regulate the temperature during the test, thereby simulating deep environments at different temperatures; moreover, by dynamically correcting the force of the pressure system through a temperature-displacement corrector, the additional force caused by thermal expansion or cold contraction can be reduced, thereby improving the accuracy of stress control.

[0009] According to some embodiments of this application, the shear box includes an upper shear box and a lower shear box. The inner sidewall of the upper shear box is provided with a first force-bearing block that can contact the soil and rock sample. The inner sidewall of the lower shear box is provided with a second force-bearing block that can contact the soil and rock sample. The projections of the first force-bearing block and the second force-bearing block in a first direction do not coincide.

[0010] According to some embodiments of this application, the temperature-displacement corrector is mounted on the first force block and the second force block.

[0011] According to some embodiments of this application, the pressure head includes a first pressure head and a second pressure head, the first pressure head and the second pressure head are arranged along a first direction, and the first pressure head and the second pressure head together apply extrusion force to the shear box.

[0012] According to some embodiments of this application, the pressure head further includes a third pressure head, which is disposed along a second direction, and the third pressure head applies a force along the second direction to the shear box.

[0013] According to some embodiments of this application, the temperature-compensated seepage-shear coupling true triaxial test apparatus further includes a seepage system that injects seepage into the pressure chamber.

[0014] According to some embodiments of this application, the pressure chamber is provided with a seepage inlet and a seepage outlet, the seepage inlet is connected to the seepage system, and the seepage outlet is used to discharge the seepage inside the pressure chamber.

[0015] According to some embodiments of this application, the temperature-compensated seepage-shear coupling true triaxial testing apparatus further includes a total control system, wherein the temperature control system, the pressure application system, and the seepage system are all electrically connected to the total control system.

[0016] According to some embodiments of this application, the shear box is provided with a temperature sensor and a pressure sensor, both of which are electrically connected to the overall control system.

[0017] The control method according to a second aspect of this application, which is based on the above-described temperature-compensated seepage-shear coupling true triaxial testing apparatus, includes the following steps: The soil and rock sample is placed in the shear box, and the various sensors in the temperature-compensated seepage-shear coupling true triaxial test device are calibrated and zeroed. Set the target stress value, target confining pressure value, and target temperature parameters; The pressure application system is activated, the confining pressure loading device injects confining pressure medium into the pressure chamber, the pressure head applies force to the shear box, and the shear box converts the force into shear force against the soil and rock sample; The temperature control system is activated, and the heat transfer jacket is used to transfer heat to the shear box. The multi-point thermometer monitors the temperature of the soil and rock sample in real time. If the force applied by the pressure system deviates from the set value due to the expansion or contraction of the soil sample during the heating or cooling process, the temperature-displacement corrector issues a correction command to the pressure system to adjust the applied force. Once the stress field, seepage field, and temperature field have all reached a stable state, stress, displacement, temperature, and seepage data are recorded simultaneously.

[0018] The control method according to the embodiments of this application has at least the following beneficial effects: during the heating or cooling process, the thermal expansion and contraction of the soil and rock sample can be sensed by the temperature-displacement corrector, thereby correcting and adjusting the pressure system so that the applied force is always at a predetermined value and the experimental results are more accurate.

[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-compensated seepage-shear coupling true triaxial test apparatus according to the first aspect of this application; Figure 2 This is a schematic diagram showing the connections of the components of the temperature-compensated seepage-shear coupling true triaxial test apparatus according to the first aspect of this application.

[0022] Reference numerals: 100-Pressure chamber, 110-Seepage inlet, 120-Seepage outlet, 200-Shear box, 210-Upper shear box, 220-Lower shear box, 300-Temperature control system, 310-Heat transfer jacket, 320-Multi-point thermometer, 330-Temperature controller, 411-First pressure head, 412-Second pressure head, 413-Third pressure head, 420-Pressure controller, 430-Cooling equipment, 500-Temperature-displacement corrector, 600-Seepage system, 700-General control system, 710-Temperature sensor, 720-Pressure sensor, 800-Soil and rock sample. 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] Deep underground engineering rock and soil masses are typically situated in complex environments characterized by high ground stress, high osmotic pressure, high temperature, and dynamic disturbance. Under these "three highs and one disturbance" conditions, the mechanical properties and seepage patterns of the rock and soil masses undergo significant changes. Research on the characteristics of these deep rock and soil masses is of high reference value for deep resource development engineering. In deep environments, rock and soil masses are not only subjected to complex mechanical compression but also to high temperature and high pressure. Temperature directly affects the elastic modulus, shear strength, and Poisson's ratio, and indirectly influences the seepage behavior of the rock and soil masses by altering the viscosity of the seepage medium and the seepage path, thereby affecting the stability of deep rock masses.

[0029] Existing true triaxial test apparatuses for seepage-shear coupling can simulate the stress conditions of soil and rock masses in deep environments, but they still have shortcomings in temperature control. Single heating or cooling methods can easily lead to large temperature differences between the core and surface of the sample, resulting in insufficient temperature field uniformity and making it difficult to realistically reproduce the multi-field coupling state of deep soil and rock masses. Moreover, soil and rock samples will expand or contract at different temperatures, which indirectly affects the magnitude of the normal or shear force applied to the soil and rock samples, leading to inaccurate experimental data.

[0030] Therefore, current seepage shear test models for deep underground rock and soil still require precise temperature control to simulate the changes in rock and soil at different temperatures. At the same time, mechanical corrections are needed for the thermal expansion and contraction of rock and soil samples to improve the accuracy of experimental data.

[0031] In response, this application proposes a temperature-compensated seepage shear coupling true triaxial testing device. This testing device is equipped with a temperature control system to precisely regulate the temperature during the test, thereby simulating deep environments at different temperatures. Moreover, by dynamically correcting the force of the pressure system through a temperature-displacement corrector, it can reduce the additional force caused by thermal expansion or cold contraction and improve the stress control accuracy.

[0032] In addition, this application also proposes a control method for the above-mentioned temperature-compensated seepage-shear coupling true triaxial test device. During the heating or cooling process, the thermal expansion and contraction of the soil sample can be sensed by the temperature-displacement corrector, and the pressure system can be corrected and adjusted accordingly, so that the applied force is always at a predetermined value and the experimental results are more accurate.

[0033] Reference Figure 1 and Figure 2 The temperature-compensated seepage-shear coupling true triaxial testing apparatus in the first aspect of this application includes a pressure chamber 100, a shear box 200, a temperature control system 300, a pressure application system, and a temperature-displacement corrector. The pressure chamber 100 is the main structure of this temperature-compensated seepage-shear coupling true triaxial testing apparatus, in which soil and rock tests in deep environments are conducted. The pressure chamber 100 creates a sealed environment, allowing the injection of confining pressure media to simulate a deep high-pressure environment. Its sealed structure also provides insulation, preventing temperature fluctuations during the test due to external environmental influences. The shear box 200 is located within the pressure chamber 100 and can be compressed by the pressure application system. The shear box 200 converts the compressive force of the pressure application system into shear force on the soil and rock sample 800. The temperature control system 300 monitors and adjusts the temperature within the pressure chamber 100. The pressure application system outputs the applied force and confining pressure, placing the shear box 200 under stress. The temperature-displacement corrector is used to adjust the output of the pressure system for the thermal expansion and contraction of the soil and rock sample 800, so that the soil and rock sample 800 is subjected to stable force and the force does not fluctuate due to thermal expansion and contraction.

[0034] Specifically, a cavity for mounting the soil and rock sample 800 is formed inside the shear box 200. After being subjected to force, the shear box 200 will undergo a slight displacement, thereby transmitting the force to the soil and rock sample 800 inside.

[0035] The temperature control system 300 includes a heat transfer jacket 310, a multi-point thermometer 320, and a temperature controller 330. The heat transfer jacket 310 is fitted over the shear box 200 and is a heat conversion device that generates heat or cold under the influence of external energy (such as electrical energy), thereby causing the shear box 200 to heat up or cool down, and thus affecting the temperature of the soil and rock sample 800 inside. The multi-point thermometer 320 is connected to the shear box 200 and is located inside the cavity of the shear box 200; it is used to detect the internal temperature of the shear box 200. Both the heat transfer jacket 310 and the multi-point thermometer 320 are electrically connected to the temperature controller 330, thereby enabling closed-loop control of the output power of the heat transfer jacket 310 based on the temperature detection results of the multi-point thermometer 320.

[0036] Furthermore, the multi-point thermometer 320 is equipped with multiple temperature detection ports, which enables multi-point detection of the temperature within the shear box 200, avoiding erroneous detection results due to uneven temperature.

[0037] The pressure application system includes a confining pressure loading device, a pressure head, and a pressure controller 420. The confining pressure loading device is used to inject a confining pressure medium into the pressure chamber 100, thereby increasing the pressure inside the pressure chamber 100. In this application, the confining pressure medium can be a gas or a liquid. The pressure head applies a force to the shear box 200, thereby subjecting the soil and rock sample 800 to normal pressure or shear force. Both the confining pressure loading device and the pressure head are poweredly connected to the pressure controller 420, which means that the pressure controller 420 outputs a power medium to the confining pressure loading device and the pressure head, including but not limited to outputting electrical energy, hydraulic oil, and high-pressure gas.

[0038] The temperature-displacement corrector 500 is electrically connected to the temperature control system 300 and the pressure application system. It corrects the force applied by the pressure application system based on the temperature measurement results of the temperature control system 300, thereby avoiding additional forces caused by the thermal expansion and contraction of the soil and rock sample.

[0039] Furthermore, the shear box 200 includes an upper shear box 210 and a lower shear box 220. The inner wall of the upper shear box 210 is provided with a first force-bearing block capable of contacting the soil and rock sample 800, and the inner wall of the lower shear box 220 is provided with a second force-bearing block capable of contacting the soil and rock sample 800. It is worth noting that the first force-bearing block and the second force-bearing block are in contact in the first direction (refer to...). Figure 1 The projections of the soil sample (in the x-direction) do not coincide. Therefore, under the pressure of the indenter, the soil sample 800 can be subjected to forces along different axes, thus generating shear force.

[0040] Furthermore, the temperature-displacement corrector is installed on the first and second force blocks, thereby enabling accurate detection of the magnitude of the force currently applied to the soil and rock sample 800.

[0041] Furthermore, the pressure head includes a first pressure head 411 and a second pressure head 412, which are arranged along a first direction. The first pressure head 411 and the second pressure head 412 together apply a compressive force to the shear box 200, which is then converted into a shear force for the soil and rock sample 800 under the conversion of the shear box 200.

[0042] Furthermore, the pressure head also includes a third pressure head 413, which is along the second direction (refer to...). Figure 1 In the z-direction setting, the third pressure head 413 applies a force along the second direction to the shear box 200, thereby forming a normal force on the soil and rock sample 800.

[0043] Furthermore, the pressure system also includes a cooling device 430, which is used to cool the pressure controller 420 to prevent high temperature from interfering with the normal operation of the pressure controller 420.

[0044] Furthermore, this temperature-compensated seepage-shear coupling true triaxial test apparatus also includes a seepage system 600, which injects seepage into the pressure chamber 100 to simulate the effect of seepage on soil and rock masses in deep environments.

[0045] Furthermore, the pressure chamber 100 is provided with a seepage inlet 110 and a seepage outlet 120. The seepage inlet 110 is connected to the seepage system 600, so that the seepage system 600 can inject seepage into the pressure chamber 100 through the seepage inlet 110. The seepage outlet 120 is used to discharge the seepage in the pressure chamber 100, thereby avoiding the continuous injection of seepage from changing the pressure inside the pressure chamber 100 and thus causing errors in the test results.

[0046] Furthermore, this temperature-compensated seepage-shear coupling true triaxial test apparatus also includes a total control system 700. The temperature control system 300, the pressure application system, and the seepage system 600 are all electrically connected to the total control system 700 and are under the comprehensive control of the total control system 700.

[0047] Furthermore, the shear box 200 is equipped with a temperature sensor 710 and a pressure sensor 720. Both the temperature sensor 710 and the pressure sensor 720 are electrically connected to the main control system 700, so that the main control system 700 can directly obtain the temperature and pressure conditions inside the shear box 200.

[0048] A control method according to a second aspect embodiment of this application, based on the above-described temperature-compensated seepage-shear coupling true triaxial test apparatus, includes the following steps: S100. Place the soil and rock sample 800 into the shear box 200, and calibrate and zero the various sensors in the temperature-compensated seepage-shear coupling true triaxial test device to prepare for subsequent tests. S200. Set the target stress value, target confining pressure value, and target temperature parameters; S300. Start the pressure application system. The confining pressure loading device injects confining pressure medium into the pressure chamber 100. The pressure head applies force to the shear box 200. The shear box 200 converts the force into shear force against the soil and rock sample 800. S400. Start the temperature control system 300, use the heat transfer jacket 310 to transfer heat to the shear box 200, and use the multi-point thermometer 320 to monitor the temperature of the soil and rock sample 800 in real time. S500. During the heating or cooling process, if the force applied by the pressure system deviates from the set value due to the expansion or contraction of the soil and rock sample 800, the temperature-displacement corrector 500 issues a correction command to the pressure system to adjust the applied force. S600. Once the stress field, seepage field, and temperature field have all reached a stable state, record the stress, displacement, temperature, and seepage data simultaneously.

[0049] 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-compensated seepage-shear coupling true triaxial testing apparatus, characterized in that, include: Pressure chamber; A shear box is disposed in the pressure chamber, and a cavity for mounting the soil and rock sample is formed inside the shear box. A temperature control system includes a heat transfer jacket, a multi-point thermometer, and a temperature controller. The heat transfer jacket is fitted over the outside of the shear box, and the multi-point thermometer is connected to the shear box and disposed in the cavity. Both the heat transfer jacket and the multi-point thermometer are electrically connected to the temperature controller. The pressure application system includes a confining pressure loading device, a pressure head, and a pressure controller. The confining pressure loading device is used to inject a confining pressure medium into the pressure chamber, and the pressure head applies a force to the shear box. Both the loading device and the pressure head are poweredly connected to the pressure controller. A temperature-displacement corrector is electrically connected to the temperature control system and the pressure application system, and corrects the force applied by the pressure application system based on the temperature measurement results of the temperature control system.

2. The temperature-compensated seepage-shear coupling true triaxial testing apparatus according to claim 1, characterized in that: The shear box includes an upper shear box and a lower shear box. The inner wall of the upper shear box is provided with a first force-bearing block that can contact the soil and rock sample. The inner wall of the lower shear box is provided with a second force-bearing block that can contact the soil and rock sample. The projections of the first force-bearing block and the second force-bearing block in a first direction do not coincide.

3. The temperature-compensated seepage-shear coupling true triaxial testing apparatus according to claim 2, characterized in that: The temperature-displacement corrector is installed on the first force block and the second force block.

4. The temperature-compensated seepage-shear coupling true triaxial testing apparatus according to claim 1, characterized in that: The pressure head includes a first pressure head and a second pressure head, which are arranged along a first direction. The first pressure head and the second pressure head together apply extrusion force to the shear box.

5. The temperature-compensated seepage-shear coupling true triaxial testing apparatus according to claim 4, characterized in that: The pressure head also includes a third pressure head, which is arranged along the second direction and applies a force along the second direction to the shear box.

6. The temperature-compensated seepage-shear coupling true triaxial testing apparatus according to claim 1, characterized in that: The temperature-compensated seepage-shear coupling true triaxial test apparatus also includes a seepage system that injects seepage into the pressure chamber.

7. The temperature-compensated seepage-shear coupled true triaxial testing apparatus according to claim 6, characterized in that: The pressure chamber is provided with a seepage inlet and a seepage outlet. The seepage inlet is connected to the seepage system, and the seepage outlet is used to discharge the seepage inside the pressure chamber.

8. The temperature-compensated seepage-shear coupling true triaxial testing apparatus according to claim 6, characterized in that: The temperature-compensated seepage-shear coupling true triaxial testing apparatus also includes a total control system, wherein the temperature control system, the pressure application system, and the seepage system are all electrically connected to the total control system.

9. The temperature-compensated seepage-shear coupling true triaxial testing apparatus according to claim 1, characterized in that: The shear box is equipped with a temperature sensor and a pressure sensor, both of which are electrically connected to the main control system.

10. A control method for a true triaxial test apparatus based on temperature compensation according to any one of claims 1 to 9, characterized in that, include: The soil and rock sample is placed in the shear box, and the various sensors in the temperature-compensated seepage-shear coupling true triaxial test device are calibrated and zeroed. Set the target stress value, target confining pressure value, and target temperature parameters; The pressure application system is activated, the confining pressure loading device injects confining pressure medium into the pressure chamber, the pressure head applies force to the shear box, and the shear box converts the force into shear force against the soil and rock sample; The temperature control system is activated, and the heat transfer jacket is used to transfer heat to the shear box. The multi-point thermometer monitors the temperature of the soil and rock sample in real time. If the force applied by the pressure system deviates from the set value due to the expansion or contraction of the soil sample during the heating or cooling process, the temperature-displacement corrector issues a correction command to the pressure system to adjust the applied force. Once the stress field, seepage field, and temperature field have all reached a stable state, stress, displacement, temperature, and seepage data are recorded simultaneously.

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