A soil dynamic triaxial multi-physical field coupling mechanical behavior testing device and system

Abstract

The application provides a soil dynamic triaxial multi-physical field coupling mechanical behavior testing device, which comprises a dynamic triaxial pressure unit, a sample unit, a water bath circulating temperature control unit, a permeation testing unit and a wave velocity testing unit. The dynamic triaxial pressure unit comprises an outer pressure chamber connected with an axial force loader and a confining pressure controller, and the axial force loader is connected with a data collector. The sample unit comprises a sample top cap, a soil sample and a sample base. The water bath circulating temperature control unit comprises a temperature exchange chamber used for accommodating the soil sample and filled with silicon oil as a heat transfer medium. The temperature exchange chamber is connected with a temperature control system, and the experimental temperature of the soil sample is regulated by adjusting the water bath circulating temperature. The permeation testing unit is connected with the sample top cap and the sample base, and is used for applying a permeation pressure on the soil sample. The wave velocity testing unit is connected with the sample top cap and the sample base, and is used for exciting and receiving an elastic wave signal in the soil sample.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering testing, and specifically relates to a soil dynamic triaxial multiphysics field coupled mechanical behavior testing device and system. Background Technology

[0002] Dynamic triaxial testing equipment is an important tool for studying the mechanical response characteristics of soil under simulated dynamic loads such as earthquakes, traffic, and waves. It is widely used in geotechnical engineering, transportation engineering, marine engineering, and energy geotechnical engineering. Traditional dynamic triaxial testing systems can perform stress-controlled consolidation experiments of saturated and unsaturated soils, standard triaxial experiments, stress path experiments, and dynamic triaxial experiments, providing a key experimental platform for studying the mechanical behavior of soil under complex stress paths.

[0003] With the advancement of major geotechnical engineering projects such as marine energy engineering, the Sichuan-Tibet Railway, and highways in cold regions, as well as the rapid development of energy geotechnical engineering fields such as deep-earth resource development, geothermal energy development, nuclear waste geological disposal, and oil and gas storage, the engineering environment of soil and rock masses is becoming increasingly complex, exhibiting significant multi-field coupling characteristics of temperature, stress, and seepage fields. For example, in deep geological nuclear waste repositories, the surrounding rock mass is simultaneously subjected to the combined effects of geostress, thermal stress, and groundwater seepage; in the development of enhanced geothermal systems, high-temperature fluid circulation leads to a severe thermo-hydraulic-mechanical coupling process in the soil and rock mass; in roadbed engineering in cold regions, the soil faces the coupled effects of freeze-thaw cycles and traffic dynamic loads. Existing research shows that the coupling effect of multiple physical fields has a significant impact on the mechanical properties, permeability, and long-term stability of soil and rock masses, and experimental methods that only consider a single factor are insufficient to fully reveal their true mechanical behavior in complex environments.

[0004] Therefore, how to provide a soil dynamic triaxial multi-physics field coupled mechanical behavior testing device to realize the mechanical behavior testing of soil samples in a complex multi-field coupled environment, and simulate the multi-physics field coupled geological environment and complex stress state of geotechnical engineering is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the aforementioned technical problems, in a first aspect, the present invention provides a soil dynamic triaxial multiphysics coupled mechanical behavior testing device, the system comprising: A dynamic triaxial pressure unit, comprising an outer pressure chamber connected to an axial force loader and a confining pressure controller, wherein the axial force loader is connected to a data acquisition unit; The sample unit includes a sample cap, a soil sample, and a sample base. A water bath circulating temperature control unit includes a temperature exchange chamber located within an external pressure chamber. The soil sample is placed within the temperature exchange chamber. An axial force loader passes through the temperature exchange chamber and is connected to the top cap of the sample. The temperature exchange chamber is connected to a temperature control system. A permeability testing unit, which is connected to the top cap of the sample and the base of the sample, is used to apply permeability pressure to the soil sample. A wave velocity testing unit, which is connected to the top cap of the sample and the base of the sample, is used to excite and receive elastic wave signals in the soil sample.

[0006] In the first aspect, the outer wall of the temperature exchange chamber has a double-layer hollow structure to form a water bath circulation space, which is used to fill condensate liquid and is connected to the temperature control system through a refrigerant circulation pipe.

[0007] In the first aspect, a temperature sensor is also provided in the temperature exchange chamber. The temperature sensor is arranged on the side of the soil sample and is communicatively connected to the temperature control system.

[0008] In the first aspect, the wave velocity testing unit includes two bending element probes, which are respectively installed on the top cap of the sample and the base of the sample, and both bending element probes are in contact with the top and bottom surfaces of the soil sample; both bending element probes are communicatively connected to the data acquisition unit.

[0009] In the first aspect, the bending element probe includes two piezoelectric ceramic sheets and a gasket; the gasket is located between the two piezoelectric ceramic sheets and is bonded to the two piezoelectric ceramic sheets.

[0010] In the first aspect, the permeation testing unit includes an upper head controller and a lower head controller, which are respectively connected to the sample cap and the sample base via fluid pipelines.

[0011] In the first aspect, the sample unit is further provided with a rubber membrane, which covers the outside of the soil sample and is sealed to the sides of the sample cap and the sample base, respectively.

[0012] Secondly, the present invention provides a soil dynamic triaxial multiphysics coupled mechanical behavior testing system, the system comprising: The soil dynamic triaxial multiphysics coupled mechanical behavior testing device described in any of the above items; A central controller, equipped with a processor and a memory, wherein the memory stores a computer program, and the processor, when running the computer program, can perform the following steps: The dynamic triaxial pressure unit is controlled to apply a preset confining pressure and axial load to the soil sample, and the axial stress data, axial strain data and confining pressure data generated by the soil sample during the loading process are acquired in real time through the data acquisition device and the confining pressure controller. The water bath circulation temperature control unit is controlled to apply a preset temperature field to the soil sample, and the temperature data of the soil sample is acquired in real time through the temperature sensor. The permeability testing unit is controlled to apply a preset osmotic pressure to the soil sample and the permeability coefficient of the soil sample is obtained during the permeation process. The wave velocity testing unit is controlled to excite and receive elastic wave signals passing through the soil sample, and wave velocity data is obtained through the bending element probe in the wave velocity testing unit. The axial stress data, axial strain data, confining pressure data, temperature data, permeability coefficient, and wave velocity data are collected and recorded as multi-physics response data of the soil sample under the coupling effects of temperature field, stress field, seepage field, and wave field.

[0013] In the second aspect, the outer wall of the temperature exchange chamber has a double-layered hollow structure, which forms a water bath circulation space. The water bath circulation temperature control unit applies a preset temperature field to the soil sample, and the temperature sensor acquires the temperature data of the soil sample in real time, including: Silicone oil is poured into the temperature exchange chamber until it submerges the upper surface of the top cap of the sample, so that the soil sample is completely immersed in the silicone oil. The temperature control system inputs circulating condensate into the water bath circulation space, thereby changing the temperature of the silicone oil around the soil sample through heat exchange. The temperature sensor monitors the temperature data of the sample in real time and feeds it back to the temperature control system. The temperature control system dynamically adjusts the circulating temperature of the condensate in the refrigerant circulation pipe according to the temperature data, so as to control the temperature data of the sample at the target value.

[0014] In the second aspect, the permeability testing unit includes an upper water head controller and a lower water head controller respectively connected to the top cap of the sample and the base of the sample. The upper water head controller and the lower water head controller are respectively connected to the top cap of the sample and the base of the sample via fluid pipelines. Controlling the permeability testing unit to apply a preset osmotic pressure to the soil sample and obtaining the permeability coefficient of the soil sample during the permeation process includes: The soil sample is sealed between the sample cap and the sample base using the rubber membrane. The upper head controller is filled with water, and the lower head controller is emptied, so that the water in the upper head controller flows into the lower head controller through the soil sample under the action of pressure difference. The volume changes of water inside the upper head controller and the lower head controller are obtained, and the permeability coefficients on the upper head side and the lower head side are obtained respectively. The permeability coefficient of the soil sample is obtained by averaging the permeability coefficients of the upper and lower water heads.

[0015] Beneficial effects: This invention proposes a triaxial multiphysics coupled mechanical behavior testing device for soil. The system includes a triaxial pressure unit, a sample unit, a water bath circulation temperature control unit, a permeability testing unit, and a wave velocity testing unit. The triaxial pressure unit includes an external pressure chamber connected to an axial force loader and a confining pressure controller. The axial force loader is connected to a data acquisition unit. The sample unit includes a sample cap, a soil sample, and a sample base. The water bath circulation temperature control unit includes a temperature exchange chamber located within the external pressure chamber. The temperature exchange chamber contains the soil sample and is filled with silicone oil as a heat transfer medium. The axial force loader passes through the temperature exchange chamber and is connected to the sample cap to provide axial force to the soil sample. The temperature exchange chamber is connected to a temperature control system, which adjusts the water bath circulation temperature to test the soil sample. The experimental temperature is regulated to achieve efficient temperature control and accurate measurement of soil sample volume change under temperature-variable load conditions, enabling mechanical tests of soil samples under different stress paths under temperature-variable load conditions. The permeability testing unit is connected to the sample cap and sample base. By setting up the permeability testing unit, it is used to apply osmotic pressure to the soil sample to conduct constant head permeability tests and constant flow velocity permeability tests, and to test the permeability coefficient of soil samples under different axial stresses and confining pressures. The wave velocity testing unit is connected to the sample cap and sample base to excite and receive elastic wave signals in the soil sample, and to conduct permeability coefficient tests of soil samples under different axial stresses and confining pressures, realizing the joint determination of soil mechanical parameters and wave velocity parameters, broadening the testing function of the device and expanding the testing range. This enables the construction of a soil dynamic triaxial testing device that integrates multi-physics field coupling testing functions such as temperature field, stress field, seepage field and wave field. By setting up a water bath circulating temperature control unit, a permeability testing unit and a wave velocity testing unit, it simulates the multi-physics field coupling geological environment and complex stress state of geotechnical engineering, and realizes the mechanical behavior testing of soil samples under complex multi-field coupling environment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the soil motion triaxial multiphysics field coupled mechanical behavior testing device in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the sample unit of the soil dynamic triaxial multiphysics field coupled mechanical behavior testing device in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the bending element probe of the soil motion triaxial multiphysics field coupled mechanical behavior testing device in Embodiment 1 of the present invention; Figure 4 This is a flowchart illustrating the soil dynamics triaxial multiphysics field coupled mechanical behavior testing system in Embodiment 2 of the present invention. Figure 5 This is a flowchart illustrating the temperature control steps of the soil sample in the soil dynamic triaxial multiphysics field coupled mechanical behavior testing system of Embodiment 2 of the present invention. Figure 6 This is a flowchart illustrating the seepage application steps of the soil sample in the soil dynamic triaxial multiphysics coupled mechanical behavior testing system of Embodiment 2 of the present invention. Explanation of reference numerals in the attached figures: 1. External pressure chamber; 2. Axial force loader; 3. Confining pressure controller; 4. Data acquisition unit; 5. Specimen top cap; 6. Soil specimen; 7. Specimen base; 8. Temperature exchange chamber; 9. Temperature control system; 10. Water bath circulation space; 11. Refrigerant circulation pipe; 12. Temperature sensor; 13. Bending element probe; 14. Piezoelectric ceramic plate; 15. Gasket; 16. Upper water head controller; 17. Lower water head controller; 18. Central controller; Detailed Implementation

[0018] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] Furthermore, in the embodiments of this specification, when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is considered to be "set on" another component, it can be directly set on the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in the embodiments of this specification are for illustrative purposes only and are not intended to limit the invention.

[0020] Example 1: like Figure 1 As shown in the figure, this embodiment provides a soil dynamic triaxial multiphysics coupled mechanical behavior testing device, the system including: The dynamic triaxial pressure unit includes an outer pressure chamber 1, which is connected to an axial force loader 2 and a confining pressure controller 3. The axial force loader 2 is connected to a data acquisition unit 4. The sample unit includes a sample cap 5, a soil sample 6, and a sample base 7. The water bath circulating temperature control unit includes a temperature exchange chamber 8, which is located inside the external pressure chamber 1. The soil sample 6 is located inside the temperature exchange chamber 8. The axial force loader 2 passes through the temperature exchange chamber 8 and is connected to the sample top cap 5. The temperature exchange chamber 8 is connected to the temperature control system 9. The permeability testing unit is connected to the specimen cap 5 and the specimen base 7 and is used to apply permeability pressure to the soil specimen 6. The wave velocity testing unit is connected to the specimen cap 5 and the specimen base 7, and is used to excite and receive elastic wave signals in the soil specimen 6.

[0021] Specifically, Embodiment 1 of the present invention proposes a soil dynamic triaxial multiphysics coupled mechanical behavior testing device. The system includes a dynamic triaxial pressure unit, a sample unit, a water bath circulating temperature control unit, a permeability testing unit, and a wave velocity testing unit. The dynamic triaxial pressure unit includes an external pressure chamber 1, which is connected to an axial force loader 2 and a confining pressure controller 3. The axial force loader 2 is connected to a data acquisition unit 4. As an feasible approach, considering the heat preservation requirements, the confining pressure is applied by air pressure. The air pressure controller has a maximum inlet pressure of 1.3 MPa and a maximum outlet pressure of 1 MPa. The sample unit includes a sample cap 5, a soil sample 6, and a sample base 7. The water bath circulating temperature control unit includes a temperature exchange chamber 8, which is located inside the external pressure chamber 1. The temperature exchange chamber 8 is used to accommodate the soil sample 6 and is filled with silicone oil as a heat transfer medium. The axial force loader 2 passes through the temperature exchange chamber 8 and is connected to the sample cap 5, which is the soil sample 6. The device provides axial force; the temperature exchange chamber 8 is connected to the temperature control system 9, which regulates the experimental temperature of the soil sample 6 by adjusting the water bath circulation temperature, achieving efficient temperature control and accurate measurement of the volumetric strain of the soil sample 6 under temperature-variable load conditions, and conducting mechanical tests of the soil sample 6 under different stress paths under temperature-variable load conditions; the permeability testing unit is connected to the sample cap 5 and the sample base 7, which is used to apply permeability pressure to the soil sample 6, conduct constant head permeability tests and constant flow velocity permeability tests, and test the permeability coefficient of the soil sample 6 under different axial stresses and confining pressures; the wave velocity testing unit is connected to the sample cap 5 and the sample base 7, which is used to excite and receive elastic wave signals in the soil sample 6, conduct permeability coefficient tests of the soil sample 6 under different axial stresses and confining pressures, realize the joint determination of soil mechanical parameters and wave velocity parameters, broaden the testing function of the device, and expand and improve the testing range.

[0022] In some possible implementations, the outer wall of the temperature exchange chamber 8 has a double-layer hollow structure to form a water bath circulation space 10, which is used to fill condensate liquid. The water bath circulation space 10 is connected to the temperature control system 9 through a refrigerant circulation pipe 11.

[0023] Specifically, the outer wall of the temperature exchange chamber 8 adopts a double-layer hollow structure design, forming a water bath circulation space 10. The temperature control system 9 delivers circulating condensate to the water bath circulation space 10 through the refrigerant circulation pipe 11, and changes the temperature of the silicone oil filled in the temperature exchange chamber 8 through heat exchange, so that the temperature of the silicone oil reaches the experimental target temperature consistent with the temperature of the condensate. This achieves uniform heating or cooling of the soil sample 6 immersed in the silicone oil, regulating the temperature of the soil sample 6. By circulating the water bath, the condensate is prevented from directly contacting the sample, indirectly regulating the temperature of the soil sample 6 and ensuring that the soil sample 6 reaches the experimental target temperature. As an feasible method, the water bath circulation temperature control unit and the temperature control system 9 are compatible with GDSLAB control software to achieve automated temperature control and real-time acquisition. At the same time, considering factors such as the temperature sensor 12, internal sealing components, and insulation, the experimental target temperature of the soil sample 6 is controlled within the range of -20 to 65°C. The condensate in the water bath circulation uses low-viscosity silicone oil.

[0024] In some possible implementations, a temperature sensor 12 is also provided in the temperature exchange chamber 8. The temperature sensor 12 is arranged on the side of the soil sample 6 and is communicatively connected to the temperature control system 9.

[0025] Specifically, a temperature sensor 12 is installed inside the temperature exchange chamber 8. The temperature sensor 12 detects the temperature data of the soil sample 6 in real time and feeds the detected temperature data back to the temperature control system 9 in real time. The temperature control system 9 dynamically adjusts the circulation temperature of the condensate in the refrigerant circulation pipe 11 according to the received temperature data, forming a closed-loop control circuit, thereby accurately controlling the sample temperature at the experimental target temperature. As an achievable method, the temperature control resolution is not less than 0.01℃.

[0026] In some possible implementations, the wave velocity testing unit includes two bending element probes 13, which are respectively installed on the sample cap 5 and the sample base 7, and both bending element probes 13 are in contact with the top and bottom surfaces of the soil sample 6; both bending element probes 13 are communicatively connected to the data acquisition unit 4.

[0027] Specifically, the wave velocity testing unit includes two bending element probes 13, which are respectively embedded in the sample cap 5 and the sample base 7. One probe serves as the transmitter, and the other as the receiver. The bending element probe 13, acting as the transmitter, excites elastic waves into the soil sample 6, while the bending element probe 13, acting as the receiver, senses the elastic waves passing through the soil sample 6 and converts them into electrical signals. The data acquisition unit 4 collects the excitation and reception signals in real time and calculates the compression wave velocity and / or shear wave velocity of the soil sample 6 based on the elastic wave propagation time and the height of the soil sample 6. This enables the testing of the shear wave velocity of the soil sample 6 under different stress states, and also allows for the testing of the compression wave velocity. Furthermore, the excitation and acquisition frequencies of the bending element probes 13 can be freely changed during the experiment to achieve the excitation and acquisition of square waves, triangular waves, sine waves, and artificially input waves, enabling the testing of the permeability coefficient of the soil sample 6 under different axial stresses and confining pressures.

[0028] In some possible implementations, the bending element probe 13 includes two piezoelectric ceramic sheets 14 and a gasket 15; the gasket 15 is located between the two piezoelectric ceramic sheets 14 and is bonded to the two piezoelectric ceramic sheets 14.

[0029] Specifically, the bending element probe 13 includes two piezoelectric ceramic plates 14 and a gasket 15. The middle gasket 15 is preferably made of phosphor bronze, while the two sides are piezoelectric ceramic plates 14. Furthermore, during device manufacturing, the bending element circuitry extends into the temperature exchange chamber 8 through the channels of the twelve-channel ring and connects to the sample base 7 and sample cap 5, where the bending element is installed. The junction between the bending element circuitry and the temperature exchange chamber 8 is sealed with a sealing ring and bolts to ensure no leakage under pressure. The outer circuitry is connected to the data acquisition unit 4 and the central controller 18.

[0030] In some possible implementations, the permeation test unit includes an upper head controller 16 and a lower head controller 17, which are connected to the sample cap 5 and the sample base 7 respectively via fluid pipelines.

[0031] Specifically, the permeability testing unit includes an upper head controller 16 and a lower head controller 17. Both the upper head controller 16 and the lower head controller 17 are high-precision pressure-volume controllers, capable of accurately controlling water pressure and measuring water volume changes in real time. During the permeability test, the upper head controller 16 is filled with water, while the lower head controller 17 is emptied, making the upper head pressure greater than the lower head pressure, forming a vertically downward seepage path. Under the action of the pressure difference, the water in the upper head controller 16 flows into the water in the lower head controller 17 through the soil sample 6. At this time, the upper and lower controllers synchronously record the volume changes of the water inside. According to Darcy's law, the permeability coefficients on the upper head side and the lower head side can be calculated separately. The two permeability coefficient values ​​will have a slight difference, and the average of the two is taken as the permeability coefficient of the soil sample 6.

[0032] In some possible implementations, the sample unit is also provided with a rubber membrane, which covers the outside of the soil sample 6 and is sealed to the sides of the sample cap 5 and the sample base 7, respectively.

[0033] Specifically, the sample unit is also equipped with a rubber membrane, which covers the outside of the soil sample 6 and is sealed to the sides of the sample cap 5 and the sample base 7 respectively, forming a reliable sealing assembly. This isolates the confining pressure medium from the pore water inside the soil sample 6, while allowing the confining pressure to be uniformly transmitted to the side of the sample, ensuring that the stress conditions of the triaxial test are accurate and controllable.

[0034] Example 2: This invention provides a soil dynamic triaxial multiphysics coupled mechanical behavior testing system, the system comprising: A soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to any one of the embodiments in Example 1; Central controller 18, which is equipped with a processor and a memory, stores a computer program in the memory. When the processor runs the computer program, it can perform the following steps: The dynamic triaxial pressure unit is controlled to apply a preset confining pressure and axial load to the soil sample 6, and the axial stress data, axial strain data and confining pressure data generated by the soil sample 6 during the loading process are acquired in real time through the data acquisition unit 4 and the confining pressure controller 3. The water bath circulation temperature control unit applies a preset temperature field to the soil sample 6 and acquires the temperature data of the soil sample 6 in real time through the temperature sensor 12. The control permeability testing unit applies a preset osmotic pressure to the soil sample 6 and obtains the permeability coefficient of the soil sample 6 during the permeation process. The control wave velocity testing unit excites and receives elastic wave signals passing through the soil sample 6 in the soil sample 6, and acquires wave velocity data through the bending element probe 13 in the wave velocity testing unit. Axial stress data, axial strain data, confining pressure data, temperature data, permeability coefficient and wave velocity data were collected and recorded as multi-physics response data of soil sample 6 under the coupling of temperature field, stress field, seepage field and wave field.

[0035] Specifically, this embodiment two proposes a soil dynamic triaxial multiphysics coupled mechanical behavior testing system, including the soil dynamic triaxial multiphysics coupled mechanical behavior testing device of any one of embodiments one and a central controller 18. The central controller 18 integrates and controls the triaxial pressure unit, water bath circulation temperature control unit, permeability testing unit, and wave velocity testing unit, realizing the coordinated loading and synchronous data acquisition of temperature field, stress field, seepage field, and wave field, solving the technical problem that traditional equipment cannot perform multi-field coupled testing. At the same time, axial stress data, axial strain data, confining pressure data, temperature data, permeability coefficient, and wave velocity data are collected and recorded as multiphysics response data of soil sample 6 under the coupled action of temperature field, stress field, seepage field, and wave field.

[0036] In some possible implementations, the outer wall of the temperature exchange chamber 8 has a double-layered hollow structure, which forms a water bath circulation space 10. The water bath circulation temperature control unit applies a preset temperature field to the soil sample 6, and the temperature data of the soil sample 6 is acquired in real time through the temperature sensor 12, including: Silicone oil is poured into the temperature exchange chamber 8 until it submerges the upper surface of the top cap 5 of the sample, so that the soil sample 6 is completely immersed in the silicone oil. The temperature control system 9 inputs circulating condensate into the water bath circulation space 10, and the temperature of the silicone oil around the soil sample 6 is changed through heat exchange. The temperature sensor 12 monitors the temperature data of the sample in real time and feeds it back to the temperature control system 9. The temperature control system 9 adjusts the circulating temperature of the condensate in the refrigerant circulation pipe 11 according to the temperature data, so as to control the temperature data of the sample at the target value.

[0037] Specifically, regarding the temperature control step for soil sample 6, in this second embodiment, silicone oil is used as the heat transfer medium to submerge soil sample 6. This not only has good thermal conductivity and low viscosity, but also provides electrical insulation protection for the bent element probe 13 immersed in it. The temperature control system 9 inputs circulating condensate into the water bath circulation space 10, changing the temperature of the silicone oil surrounding soil sample 6 through heat exchange. Simultaneously, temperature sensors 12 are installed on the side of soil sample 6 to monitor the temperature data of soil sample 6 in real time and feed the temperature data back to the temperature control system 9, which adjusts the circulating temperature of the condensate. The temperature control system 9 dynamically adjusts the circulating temperature of the condensate in the refrigerant circulation pipe 11 based on the temperature data to control the sample temperature at the target value.

[0038] In some possible implementations, the permeability testing unit includes an upper water head controller 16 and a lower water head controller 17, respectively connected to the sample cap 5 and the sample base 7. The upper water head controller 16 and the lower water head controller 17 are connected to the sample cap 5 and the sample base 7 via fluid pipelines, respectively, to control the permeability testing unit to apply a preset osmotic pressure to the soil sample 6 and to obtain the permeability coefficient of the soil sample 6 during the permeation process, including: The soil sample 6 is sealed between the sample cap 5 and the sample base 7 using a rubber membrane. Fill the interior of the upper water head controller 16 with water and empty the interior of the lower water head controller 17, so that the water in the upper water head controller 16 flows into the lower water head controller 17 through the soil sample 6 under the action of pressure difference. The volume changes of water inside the upper head controller 16 and the lower head controller 17 are obtained, and the permeability coefficients on the upper head side and the lower head side are obtained respectively. The permeability coefficient of soil sample 6 was obtained by averaging the permeability coefficients on the upstream and downstream sides.

[0039] Specifically, regarding the pressure application step for soil sample 6, in this embodiment, the volume change of water is simultaneously recorded by the upper head controller 16 and the lower head controller 17, and the permeability coefficient values ​​of the two controllers can be calculated separately. Since there may be minor leakage during the test, the two coefficients usually have slight differences. The average value of the two is taken as the permeability coefficient of soil sample 6, thereby reducing measurement errors and improving the accuracy and reliability of permeability coefficient testing.

[0040] Technical effect: Since this second embodiment and the first embodiment are embodiments under the same inventive concept and their structures are completely identical, the structures in the second embodiment that are substantially the same as those in the first embodiment will not be described in detail. For the parts not described in detail, please refer to the first embodiment.

[0041] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. All should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0042] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A soil dynamic triaxial multiphysics coupled mechanical behavior testing device, characterized in that, The system includes: A dynamic triaxial pressure unit, comprising an outer pressure chamber connected to an axial force loader and a confining pressure controller, wherein the axial force loader is connected to a data acquisition unit; The sample unit includes a sample cap, a soil sample, and a sample base. A water bath circulating temperature control unit includes a temperature exchange chamber located within an external pressure chamber. The soil sample is placed within the temperature exchange chamber. An axial force loader passes through the temperature exchange chamber and is connected to the top cap of the sample. The temperature exchange chamber is connected to a temperature control system. A permeability testing unit, which is connected to the top cap of the sample and the base of the sample, is used to apply permeability pressure to the soil sample. A wave velocity testing unit, which is connected to the top cap of the sample and the base of the sample, is used to excite and receive elastic wave signals in the soil sample.

2. The soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to claim 1, characterized in that: The outer wall of the temperature exchange chamber has a double-layer hollow structure to form a water bath circulation space, which is used to fill condensate liquid. The water bath circulation space is connected to the temperature control system through a refrigerant circulation pipe.

3. The soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to claim 2, characterized in that: The temperature exchange chamber is also equipped with a temperature sensor, which is located on the side of the soil sample and is communicatively connected to the temperature control system.

4. The soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to claim 1, characterized in that: The wave velocity testing unit includes two bending element probes, which are respectively installed on the top cap of the sample and the base of the sample, and both bending element probes are in contact with the top and bottom surfaces of the soil sample; both bending element probes are communicatively connected to the data acquisition unit.

5. The soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to claim 4, characterized in that: The bending element probe includes two piezoelectric ceramic plates and a gasket; the gasket is located between the two piezoelectric ceramic plates and is bonded to the two piezoelectric ceramic plates.

6. The soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to claim 1, characterized in that: The permeation testing unit includes an upper head controller and a lower head controller, which are respectively connected to the sample cap and the sample base via fluid pipelines.

7. The soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to claim 1, characterized in that: The sample unit is also provided with a rubber membrane, which covers the outside of the soil sample and is sealed to the top cap of the sample and the side of the sample base, respectively.

8. A soil dynamic triaxial multiphysics coupled mechanical behavior testing system, characterized in that, The system includes: The soil dynamic triaxial multiphysics coupled mechanical behavior testing device according to any one of claims 1-7; A central controller, equipped with a processor and a memory, wherein the memory stores a computer program, and the processor, when running the computer program, can perform the following steps: The dynamic triaxial pressure unit is controlled to apply a preset confining pressure and axial load to the soil sample, and the axial stress data, axial strain data and confining pressure data generated by the soil sample during the loading process are acquired in real time through the data acquisition device and the confining pressure controller. The water bath circulation temperature control unit is controlled to apply a preset temperature field to the soil sample, and the temperature data of the soil sample is acquired in real time through the temperature sensor. The permeability testing unit is controlled to apply a preset osmotic pressure to the soil sample and the permeability coefficient of the soil sample is obtained during the permeation process. The wave velocity testing unit is controlled to excite and receive elastic wave signals passing through the soil sample, and wave velocity data is obtained through the bending element probe in the wave velocity testing unit. The axial stress data, axial strain data, confining pressure data, temperature data, permeability coefficient, and wave velocity data are collected and recorded as multi-physics response data of the soil sample under the coupling effects of temperature field, stress field, seepage field, and wave field.

9. The soil dynamics triaxial multiphysics coupled mechanical behavior testing system according to claim 8, characterized in that, The outer wall of the temperature exchange chamber has a double-layered hollow structure, which forms a water bath circulation space. The water bath circulation temperature control unit applies a preset temperature field to the soil sample, and the temperature sensor acquires the temperature data of the soil sample in real time, including: Silicone oil is poured into the temperature exchange chamber until it submerges the upper surface of the top cap of the sample, so that the soil sample is completely immersed in the silicone oil. The temperature control system inputs circulating condensate into the water bath circulation space, thereby changing the temperature of the silicone oil around the soil sample through heat exchange. The temperature sensor monitors the temperature data of the sample in real time and feeds it back to the temperature control system. The temperature control system dynamically adjusts the circulating temperature of the condensate in the refrigerant circulation pipe according to the temperature data, so as to control the temperature data of the sample at the target value.

10. The soil dynamics triaxial multiphysics coupled mechanical behavior testing system according to claim 8, characterized in that, The permeability testing unit includes an upper water head controller and a lower water head controller, respectively connected to the top cap of the sample and the base of the sample. The upper water head controller and the lower water head controller are respectively connected to the top cap of the sample and the base of the sample via fluid pipelines. Controlling the permeability testing unit to apply a preset osmotic pressure to the soil sample and obtaining the permeability coefficient of the soil sample during the permeation process includes: The soil sample is sealed between the sample cap and the sample base using the rubber membrane. The upper head controller is filled with water, and the lower head controller is emptied, so that the water in the upper head controller flows into the lower head controller through the soil sample under the action of pressure difference. The volume changes of water inside the upper head controller and the lower head controller are obtained, and the permeability coefficients on the upper head side and the lower head side are obtained respectively. The permeability coefficient of the soil sample is obtained by averaging the permeability coefficients of the upper and lower water heads.

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