Dynamic heat-water-force coupling test device and test method

Abstract

The invention provides a dynamic heat-water-force coupling test device and test method, and relates to the technical field of rock performance test.The device comprises a sample chamber for containing a rock sample; the heat loading assembly, the pore water pressure loading assembly and the force loading assembly are integrally arranged; the heat loading assembly comprises a heating element and a cooling element so as to simulate an environment in a wide temperature range or under a freezing and thawing cycle condition; the pore water pressure loading assembly is communicated with the rock sample to establish pore water seepage loading; an axial pressure loading element of the force loading assembly applies dynamic axial pressure to the rock sample, and a confining pressure loading element of the force loading assembly applies dynamic confining pressure to the rock sample; the sealing sleeve wraps the rock sample so as to isolate the confining pressure medium from the liquid medium. According to the device provided by the invention, three dynamic loads including the dynamic temperature, the dynamic pore water pressure and the dynamic mechanical stress can be synchronously applied and accurately controlled in a single device, so that a rock sample is subjected to a mechanical test in a vivid dynamic multi-field coupling environment.

Description

Technical Field

[0001] This application relates to the field of rock performance testing technology, and in particular to a dynamic thermo-hydraulic-mechanical coupling test device and test method. Background Technology

[0002] Rocks, especially those on periglacial slopes, are often situated in complex environments where temperature, pore water pressure, and geostress are highly coupled. However, unlike the high-temperature, high-water-pressure, and high-stress multi-physics environment of rocks in underground engineering projects such as carbon dioxide sequestration, geothermal energy development, and deep oil and gas extraction, the periglacial slope environment involves dynamic thermo-hydraulic-mechanical interactions, namely freeze-thaw cycles, pore water pressure cycles, and loading / unloading cycles. In this dynamically coupled environment, temperature changes cause thermal expansion or thermal fracture propagation in the rock, changes in pore water pressure alter the effective stress state of the rock, and stress, in turn, affects the evolution of pore structure and fluid channels. The interaction of these three factors typically leads to a strong nonlinearity, time-varying nature, and irreversibility in the rock's mechanical response, directly impacting the stability and safety of the engineering project.

[0003] Existing mechanical response testing devices under thermo-hydraulic-mechanical multi-physics environment mainly focus on the coupling effects of high permeability, high temperature, and high stress in deep rock masses. However, they typically only employ constant temperature, water pressure, and stress conditions, failing to adequately consider the rock mass response under dynamically changing environments. While some experimental methods involve dynamic thermo-hydraulic-mechanical coupling, their step-by-step loading mode of "thermal-hydraulic-mechanical pretreatment + mechanical testing" cannot truly reflect the dynamic response of rock masses under actual loading conditions in situ. Therefore, currently, there is no testing device capable of truly testing the mechanical response of rocks under dynamic thermo-hydraulic-mechanical multi-physics coupling conditions. Summary of the Invention

[0004] To address the aforementioned problems, one objective of this invention is to provide a dynamic thermo-hydraulic-mechanical coupling testing device that simultaneously applies and precisely controls three cyclic loads—temperature, pore water pressure, and mechanical stress—within a single device, enabling rock samples to undergo mechanical testing in a realistic multi-field coupling environment. A second objective of this invention is to provide a dynamic thermo-hydraulic-mechanical coupling testing method, particularly suitable for simulating and testing the in-situ mechanical properties of rocks on periglacial slopes under thermo-hydraulic-mechanical multi-physics field coupled cyclic loading.

[0005] To achieve one of its objectives, in a first aspect, the present invention provides a dynamic thermo-hydraulic-mechanical coupling test device, the technical solution of which is: A dynamic thermo-hydraulic-mechanical coupling testing apparatus includes a container body surrounding a sample chamber for accommodating a rock sample; and integrated onto the container body: A heat loading assembly includes a heating element and a cooling element. The heating element includes an electric heater surrounding the sample chamber, and the cooling element includes a refrigerator, a cold bath, and a cooling coil connected in sequence. A cooling medium flows between the cold bath and the cooling coil. The heating element and the cooling element operate individually or alternately to simulate rocks under a wide temperature range or freeze-thaw cycles. A pore water pressure loading assembly includes a seepage loop through which a liquid medium flows, the seepage loop being connected to the upper and lower ends of the rock sample to establish a saturated seepage loading with pore water pressure. The force loading assembly includes an axial pressure loading element and a confining pressure loading element. The axial pressure loading element includes an axial pressure servo pump, a loading piston, and an upper pressure head connected in sequence, with the upper pressure head pressing against the rock sample. The axial pressure servo pump drives the loading piston to move towards or away from the upper pressure head to apply dynamic axial pressure to the rock sample through the upper pressure head. The confining pressure loading element includes a confining pressure servo pump and an injection pipe connected in series. The injection pipe communicates with the sample chamber, and the confining pressure servo pump drives the injection pipe to inject or discharge confining pressure medium into the sample chamber to apply dynamic confining pressure to the rock sample. The sample chamber is equipped with a sealing sleeve that covers the rock sample to isolate the confining pressure medium and the liquid medium. The confining pressure medium and the liquid medium are liquids with low thermal expansion coefficients and high bulk moduli to support the dynamic loading of the rock under the wide temperature range or freeze-thaw cycle conditions.

[0006] As one of the preferred embodiments, the sealing sleeve is a hollow tubular body with openings at the top and bottom and a hollow interior. The upper opening of the sealing sleeve is sealed and bonded to the upper pressure head, and the lower opening is sealed and bonded to the base of the container body. An adhesive layer is filled between the hollow inner wall and the rock sample to isolate the liquid medium between the sealing sleeve and the rock sample.

[0007] As one preferred embodiment, the device further includes: The data acquisition component includes an in-situ rock damage monitoring unit, which includes an acoustic emission sensor and an ultrasonic detection component. The acoustic emission sensor is attached to the surface of the rock sample or the inner wall of the sample chamber by a coupling agent, and is used to collect elastic wave signals generated by internal cracks in the rock sample over a short distance. The ultrasonic testing component includes an ultrasonic transmitting probe and an ultrasonic receiving probe. The ultrasonic transmitting probe is embedded in the upper pressure head, and the ultrasonic receiving probe is disposed on the base of the container body for collecting ultrasonic signals penetrating the rock sample.

[0008] As one of the preferred embodiments, the upper pressure head includes a high-strength solid body, the upper pressure head encapsulates the ultrasonic transmitting probe inside, and the upper pressure head also has a fluid channel inside, the fluid channel being connected to the seepage circuit to simultaneously support ultrasonic detection and high water pressure seepage loading.

[0009] As one preferred embodiment, the device further includes an upper permeable stone and a lower permeable stone, wherein the upper permeable stone is disposed between the upper opening of the sealing sleeve and the upper end of the rock sample, and the lower permeable stone is disposed between the lower opening of the sealing sleeve and the lower end of the rock sample.

[0010] As one preferred embodiment, the cooling coil is arranged inside the sample chamber and surrounds the rock sample; wherein, the cold bath is integrated on the refrigerator and is circulated in communication with the cooling coil, so that the cooling medium is cooled in the cold bath and flows to the cooling coil, exchanges heat with the sample chamber and then flows back to the cold bath.

[0011] As one of the preferred embodiments, the pore water pressure loading assembly further includes a seepage servo pump and a back pressure control valve, and the seepage circuit includes an inlet pipe and an outlet pipe; wherein, the seepage servo pump is connected to the upper end of the rock sample through the inlet pipe; and the lower end of the rock sample is connected to the back pressure control valve through the outlet pipe.

[0012] As one preferred embodiment, the hydraulic pipeline connecting the axial pressure servo pump to the loading piston, the injection pipe connecting the confining pressure servo pump to the sample chamber, and the inlet pipe connecting the permeation servo pump to the sample chamber are all sequentially equipped with a pump-side pressure gauge, a main switch, and a chamber-side pressure gauge; and, The axial pressure servo pump is connected to the force loading oil tank through the axial pressure oil circuit, and the confining pressure servo pump is connected to the force loading oil tank through the confining pressure oil circuit. The seepage servo pump is connected to the pore water pressure loading oil tank through the seepage oil circuit. The hydraulic lines, the injection lines, and the inlet lines are all connected to the corresponding oil tanks via branch lines. A first branch switch is provided on the axial pressure oil circuit, the confining pressure oil circuit, and the seepage oil circuit, and a second branch switch is provided on the oil pipe branch.

[0013] As one of the preferred embodiments, the liquid medium and the confining pressure medium include silicone oil; and / or, the cooling medium includes at least anhydrous ethanol.

[0014] As one of the preferred solutions, the data acquisition component further includes: A temperature sensor is used to measure the temperature value inside the sample chamber; An axial pressure sensor is used to measure the axial load applied by the loading piston. A confining pressure sensor is used to measure the confining pressure value inside the sample chamber; An axial displacement sensor is used to measure the axial compressive deformation of the rock sample. A radial deformation sensor is used to measure the amount of expansion of the rock sample in the radial direction; A pore water pressure sensor is used to measure the pore water pressure of the rock sample under saturated seepage loading. The axial displacement sensor is provided in two parts, and the two axial displacement sensors are symmetrically mounted on the loading piston to form a dual-channel redundant measurement. The device also includes: The monitoring and control system is connected to the axial pressure servo pump, confining pressure servo pump, seepage servo pump, heating element and cooling element respectively, to apply axial load, confining pressure, pore water pressure and temperature according to the preset loading path; The monitoring and control system is also connected to the data acquisition component to receive and display multi-channel sensor data acquired by the data acquisition component during the loading process; the multi-channel sensor data includes at least one of ambient temperature value, temperature value, confining pressure value, axial load value, axial compression deformation, expansion, pore water pressure, elastic wave signal and ultrasonic signal. Based on the multi-channel sensor data, the corresponding axial pressure servo pump, confining pressure servo pump, seepage servo pump, heating element, and cooling element are controlled to be on the target loading path.

[0015] To achieve the second objective, the present invention provides a dynamic thermo-hydraulic-mechanical coupling test method, the technical solution of which is: A dynamic thermo-hydraulic-mechanical coupling test method suitable for periglacial slope rocks, relying on the dynamic thermo-hydraulic-mechanical coupling test apparatus as provided in the first aspect of the present invention, is used to test the in-situ mechanical response performance of periglacial slope rocks under thermo-hydraulic-mechanical coupling cyclic loading, the method comprising: The rock sample is loaded into the sealed sleeve inside the sample chamber; Activate the confining pressure loading element to apply confining pressure to the rock sample; During each cycle, the pore water pressure loading component is activated to dynamically adjust the pore water pressure applied to the rock sample, so as to simulate the ice edge slope rock under water pressure circulation conditions. In each cycle, the cooling element is turned on to lower the temperature of the sample chamber and the rock sample, causing the liquid medium to freeze; then the cooling element is turned off and the heating element is turned on to raise the temperature of the sample chamber and the rock sample, causing the liquid medium to melt, thus simulating the ice edge slope rock under freeze-thaw cycle conditions. In each cycle, the axial compression loading element is activated to apply dynamic axial pressure to the rock sample to simulate the rock on the periglacial slope under stress cycling conditions. Record the test data of the rock sample under each cycle of thermo-hydraulic-mechanical coupled synchronous dynamic loading. The test data includes at least temperature, pore water pressure and pressure load, in order to test the in-situ mechanical response performance of the rock on the periglacial slope under thermo-hydraulic-mechanical coupled cyclic loading.

[0016] Compared with the prior art, this application has the following advantages: This invention integrates temperature field, seepage field and stress field into a single device. The device can simultaneously apply three coupled cyclic loads to rock samples in the same sample chamber, including temperature cycling over a wide temperature range (-20℃ to 200℃), pore water pressure cycling, and axial pressure-confining pressure mechanical stress cycling. This enables the sample to continuously undergo the test conditions of thermal-water-mechanical multi-physics coupling under loading, overcoming the problems of time-consuming and inconsistent conditions in the step-by-step test in the prior art.

[0017] The device of this invention can complete the dynamic low-temperature freeze-thaw, heating, dynamic pressurization and saturation, and dynamic mechanical loading processes of the sample in one go, which greatly improves the test efficiency. At the same time, the coupled loading of each field is carried out synchronously in the same system, avoiding the transfer of the sample between different devices, maintaining the continuity and controllability of the temperature field, pore water pressure field and stress field, and more closely resembling the real loading state of the rock in the in-situ environment, thus improving the authenticity and accuracy of the test results.

[0018] The device described in this invention features wide-range precise temperature control and multi-channel servo loading capabilities, enabling it to simulate the effects of extreme environments (deep high temperature and pressure or high-latitude freeze-thaw cycles) on rocks. It allows for the study of the mechanical response of rocks under different temperature ranges or freeze-thaw cycles, overcoming the limitations of traditional triaxial testing systems. It is particularly suitable for simulating complex conditions such as freeze-thaw cycles in cold regions, water pressure fluctuations, and stress cycles, significantly improving testing efficiency and data reliability.

[0019] In summary, this invention has a reasonable structural design, comprehensive functions, and significantly reduces test preparation and conversion time. It has strong practicality and feasibility, and is suitable for scientific research and engineering test needs in fields such as slope rocks in high-altitude and cold regions, reservoir slope rocks during reservoir rise and fall, and periglacial slope rocks under glacial circulation.

[0020] The method and the device described above have the same advantages over the prior art, and will not be repeated here. Attached Figure Description

[0021] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a three-dimensional assembly diagram of a dynamic thermo-hydraulic-mechanical coupling test device provided in an embodiment of this application; Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a front view of the dynamic thermo-hydraulic-mechanical coupling test device provided in one embodiment of this application; Figure 4 This is a cross-sectional view of the sample chamber after loading a rock sample, according to an embodiment of this application. Figure 5 This is the connection line between the sample chamber and the external pipeline provided in one embodiment of this application; Figure 6 This is a flowchart of the steps of a dynamic thermo-hydraulic-mechanical coupling test method provided in an embodiment of this application; Figure 7 This is a graph showing the performance test results of specimen M-6 under dynamic mechanical loading according to an embodiment of this application; Figure 8 This is a graph showing the loading creep curves and their second derivative curves of a specimen numbered M-6 under dynamic mechanical loading for six cycles, provided in an embodiment of this application. Figure 9 This is a graph showing the performance test results of the sample numbered TM-6 under thermo-mechanical coupling synchronous dynamic loading according to an embodiment of this application; Figure 10 This is a graph showing the loading creep curves and their second derivative curves of sample TM-6 under thermo-mechanical coupling synchronous dynamic loading for six cycles, provided in an embodiment of this application. Figure 11 This is a graph showing the performance test results of the sample numbered THM-6 under simultaneous dynamic loading with thermo-water-mechanical coupling, according to an embodiment of this application. Figure 12 This is a graph showing the loading creep curves and their second derivative curves of sample number THM-6 during five cycles of synchronous dynamic loading with thermo-water-mechanical coupling, provided in an embodiment of this application.

[0023] Explanation of reference numerals in the attached figures: 1. Loading piston; 2. Upper pressure head; 31. Upper permeable stone; 32. Lower permeable stone; 4. Rock sample; 5. Sealing sleeve; 6. Temperature sensor; 7. Base; 8. Liquid outlet pipe; 9. Liquid inlet pipe; 10. Cold bath box; 11. Cooler; 12. Cooling coil; 13. Sample chamber; 14. Confining pressure servo pump; 15. Axial pressure servo pump; 16. Seepage servo pump; 17. Acoustic emission sensor; 18. Ultrasonic emission probe; 19. Ultrasonic receiving probe; 20. Injection pipe; 21. Axial displacement sensor; 22. Pump side pressure gauge; 23. Chamber side pressure gauge; 24. Main switch; 25. First branch switch; 26. Second branch switch; 27. Force loading oil tank; 28. Adhesive layer. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] To better understand the technical solution of this application, the existing rock mechanical property testing techniques will now be further explained: Based on the commonly used rock mechanical property testing methods or devices mentioned in the background technology, it is clear that experimental devices capable of simultaneously simulating temperature, pore water pressure, and stress changes are scarce, and most experimental conditions cannot meet the testing requirements of dynamic coupling of multiple physical fields. Due to this limitation, in existing technologies, researchers can only rely on multiple devices to complete comprehensive thermo-hydraulic-mechanical tests. Under these conditions, the saturation, heating, and mechanical loading processes of rock sample 4 often need to be completed in different devices. For example, a common experimental procedure is to first place rock sample 4 in a vacuum saturation device for saturation treatment, or place it in a separate heating chamber for temperature pretreatment, and then transfer the treated sample to a rock mechanics testing machine for mechanical loading testing. This step-by-step approach has significant shortcomings: First, the samples need to be moved between different devices multiple times, making the test process cumbersome, time-consuming, and costly in terms of manpower and resources. Second, during the handling and environmental changes, the initial conditions of the samples, such as internal temperature, pore water distribution, and stress state, are prone to change, making it difficult for the test results to truly reflect the in-situ response of the rock.

[0026] Furthermore, most triaxial rock testing machines have relatively limited temperature control functions, typically only capable of heating from room temperature to a certain high temperature range, lacking low-temperature control methods. Therefore, existing testing systems cannot simulate the mechanical behavior of real periglacial slope rocks under freeze-thaw cycles, or high-altitude slope rocks under cryogenic conditions.

[0027] In summary, current technologies lack a multi-field dynamic coupling test device capable of simultaneously applying temperature cycling, pore water pressure cycling, and mechanical load cycling to a sample within a single device. This leads to reduced test efficiency and accuracy, making it difficult to comprehensively study the mechanical properties and damage evolution of rocks under complex multi-field dynamic coupling conditions. In particular, it is difficult to reproduce the in-situ mechanical properties of rocks on periglacial slopes under dynamic changes in thermo-hydraulic-mechanical boundary conditions during glacial cycles. Therefore, simulating the mechanical response of rocks under realistic multi-physics dynamic coupling conditions not only provides reliable experimental support for studying the damage characteristics and mechanisms of rocks under complex thermo-hydraulic-mechanical coupled synchronous dynamic changes, but also has significant implications for geothermal energy development, carbon dioxide geological storage, deep engineering, and stability assessment of cold-region engineering projects.

[0028] Based on the above description, the technical solution of this invention application will be described as follows: Figure 1 and Figure 3 The figures shown are a three-dimensional assembly diagram and a front view structural diagram of the dynamic thermo-hydraulic-mechanical coupling test device shown in this invention. Figure 2 for Figure 1 A magnified view of a portion of point A in the middle. (See image below.) Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a dynamic thermo-hydraulic-mechanical coupling test device, comprising a container body surrounding a sample chamber 13 for accommodating a rock sample 4; and an integrated heat loading assembly on the container body, comprising a heating element and a cooling element, wherein the heating element is used to heat the rock sample 4 in the sample chamber 13, and the cooling element is used to cool the rock sample 4 in the sample chamber 13 to simulate rocks under different temperature ranges or freeze-thaw cycles; and a pore water pressure loading assembly, comprising a seepage loop through which a liquid medium flows, the seepage loop being connected to the upper and lower surfaces of the rock sample 4. The test chamber 13 is connected to the test chamber 13 to establish a saturated seepage load with pore water pressure; the force loading assembly includes an axial pressure loading element and a confining pressure loading element; the output end of the axial pressure loading element is movably disposed in the test chamber 13 and moves toward or away from the rock test sample 4 to apply dynamic axial pressure to the rock test sample 4; the output end of the confining pressure loading element is connected to the test chamber 13 and injects or discharges confining pressure medium into the test chamber 13 to apply dynamic confining pressure to the rock test sample 4; wherein, a sealing sleeve 5 covering the rock test sample 4 is provided in the test chamber 13 to isolate the confining pressure medium and the liquid medium.

[0029] Specifically, the container body is the shell of the device, and its hollow interior forms a sample chamber 13. The sample chamber 13 serves as the test space for the rock sample 4, isolating it from external interference and bearing the multi-physics loading forces. For example, the container body is a high-rigidity self-balancing loading frame, with a cylindrical sample chamber 13 inside the frame for holding the rock sample 4. The sample chamber 13 is made of high-strength alloy steel, capable of withstanding high confining pressure and resisting high and low temperatures. The sample chamber 13 has upper and lower openings; the upper opening is sealed by a sealing end cap, and the lower opening is sealed by a rigid base 7, making the sample chamber 13 a closed pressure chamber. The output end of the axial compression loading assembly extends into the sample chamber 13 through a sealing flange. The upper end of the rigid base 7 can be used to place the rock sample 4 loaded into the sealing sleeve 5. The rock sample 4 is typically a standard-sized cylindrical rock sample, positioned precisely between the upper end of the rigid base 7 and the upper pressure head 2. In some embodiments, multiple fluid channels can be provided on the rigid base 7 to allow tubular structures such as the inlet pipe 9, outlet pipe 8, and injection pipe 20 to pass into the sample chamber 13. The sealing sleeve 5 is made of an elastic pressure-resistant material, which isolates the rock sample 4 from the confining pressure medium to prevent leakage, thus achieving separation of confining pressure loading and pore water loading.

[0030] Preferably, the sample chamber 13 can withstand a temperature environment of -20℃ to 200℃ and a confining pressure of not less than 60MPa. Specifically, the heat loading assembly is equipped with two types of heat loading elements: a heating element and a cooling element. The heating element can heat the sample chamber 13 and the rock sample 4 therein to the required temperature (up to 200℃), while the cooling element can lower the temperature of the sample chamber 13 and the rock sample 4 therein to below -20℃. Because this application simultaneously provides heating and cooling elements, it can perform operations such as heating, cooling, isothermal loading, and cyclic temperature loading, thereby simulating the thermal environment of rocks at different depths and under different geothermal conditions.

[0031] For example, a single controlled heating element can raise the temperature to different ranges, and a single controlled cooling element can lower the temperature to different ranges, allowing rock sample 4 to be loaded within a wide temperature range of -20℃ to 200℃. This simulates the mechanical behavior of rocks at different geological depths or reservoir slope rocks under different temperature ranges. By cyclically turning the heating and cooling elements on and off and setting the number of cycles, the heat loading assembly can also achieve periodic cyclic loading within a wide temperature range, allowing rock sample 4 to be cyclically loaded within an ambient temperature range of -20℃ to 200℃. Combined with the force loading assembly and the pore water pressure loading assembly, this simulates the multi-physics coupled thermal cycling process of rocks on high-altitude cold slopes and periglacial slopes under alternating high and low temperatures or freeze-thaw cycles. For instance, by turning the heating and cooling elements on and off once, a single freeze-thaw test can be achieved, which can be used to simulate periodic temperature changes during geothermal extraction or injection. By repeatedly turning the heating and cooling elements on and off, rock sample 4 can undergo repeated freezing and thawing processes, thereby simulating the mechanical behavior of rocks on cold-climate slopes and periglacial slopes under freeze-thaw cycles.

[0032] Specifically, the pore water pressure loading component applies liquid medium to the upper and lower ends of the rock sample 4 through a seepage loop, thereby applying a predetermined pore water pressure and upstream / downstream pressure difference to simulate the underground pore water pressure and seepage environment of the rock.

[0033] Specifically, the force loading assembly includes a confining pressure loading element capable of injecting or discharging a confining pressure medium into the sample chamber 13 to adjust the magnitude of the confining pressure, and an axial pressure loading element capable of reciprocating vertically to apply axial pressure to the rock sample 4 within the sample chamber 13 via the upper pressure head 2. The axial pressure loading element may include hydraulic cylinders, servo actuators, and electric cylinders, etc., adjusting the magnitude of the axial pressure by controlling the movement direction of the loading piston 1 relative to the rock sample 4. The confining pressure loading element may include a high-pressure liquid pump or pneumatic pump, etc., injecting a confining pressure medium (water, gas, or oil) into the sample chamber 13. The confining pressure medium fills the annular space formed between the sample chamber 13, the base 7, and the upper pressure head 2, applying a uniform confining pressure in all directions to the rock sample 4. The confining pressure loading element can also depressurize the confining pressure medium, thereby applying a controllable static-dynamic confining pressure (the confining pressure can be as high as 60 MPa or more, and can be periodically fluctuated) to the outside of the rock sample 4.

[0034] In this embodiment, the heat loading component, the pore water pressure loading component, and the force loading component are integrated together. Therefore, during the loading process, the outer periphery of the rock sample 4 is covered with a sealing sleeve 5 made of fluororubber resistant to high and low temperatures, which isolates the rock sample 4 in the seepage environment from the confining pressure medium.

[0035] The inventors creatively discovered that when pore water pressure is applied, water pressure also exists between the rock sample 4 and the sealing sleeve 5, generating an inward pressure that causes the sealing sleeve 5 to expand. Conversely, the confining pressure also acts on the sealing sleeve 5, generating an inward force that causes it to contract and press against the rock sample 4. To ensure the sealing sleeve 5 is not damaged, the test requires the confining pressure to be greater than the pore water pressure; otherwise, the expansion will damage the sealing sleeve 5, allowing the confining medium to enter the rock sample 4, thus causing the test to fail. However, in reality, there are often conditions where the confining pressure is extremely low but the water pressure is extremely high, severely limiting the test conditions.

[0036] like Figure 4 The diagram shows a cross-sectional view of the specimen chamber 13 after loading rock specimen 4, and is combined with... Figure 2 As shown, in this embodiment, the upper and lower ends of the sealing sleeve 5 are respectively sealed and connected to the upper pressure head 2 and the rigid base 7, forming an independent pore water flow loop. The pore water flow loop is connected to the seepage loop, allowing the confining pressure medium to enter the upper end of the rock sample 4 and flow from the upper end of the rock sample 4 through the pore water flow loop to the lower end, and then flow out of the rock sample 4 through the seepage loop. An adhesive layer 28 is filled between the inner wall of the sealing sleeve 5 and the outer wall of the rock sample 4. Therefore, an adhesive material is used to bond the rock sample 4 and the sealing sleeve 5 to form an adhesive layer 28, while also bonding the sealing sleeve 5 to the end face of the base 7 and the end face of the upper pressure head 2, forming an independent pore water flow loop. The water flow will completely enter the interior of the rock sample 4 through the permeable stone, and will not exist between the rock sample 4 and the sealing sleeve 5, satisfying the working condition of applying high water pressure and low confining pressure. Therefore, the design of this embodiment significantly expands the working condition range of rock tests and enhances the authenticity, reliability and scientific research value of the test device.

[0037] To adapt to the rock performance research under the synchronous dynamic loading conditions of thermal-hydraulic-mechanical coupling of this device, the adhesive material used must not exhibit significant brittleness under low or high temperature conditions, and the bonding effect needs to be relatively sealed and stable. Furthermore, the adhesive should be able to be removed after the test for easy disassembly. More preferably, the adhesive layer 28 in this embodiment is an epoxy resin layer.

[0038] Preferably, the inlet pipe 9 passes through the base 7 and extends parallel to the sealing sleeve 5 to pass through the upper pressure head 2, finally connecting with the upper permeable stone 31. The section of the inlet pipe 9 located between the base 7 and the upper pressure head 2 is designed in a spiral wound shape. Due to the flexibility of the spiral section, when the inlet pipe 9 is installed on the base 7 and the upper pressure head 2, the spiral section can adaptively compress, elongate, slightly offset, and twist in the axial direction, thereby facilitating the installation and removal of the inlet pipe 9 from the upper pressure head 2 or the base 7.

[0039] In addition, the adaptive characteristics of the spiral section can maintain the smoothness of pore water pressure loading even when the upper pressure head 2 causes micro-movement or changes in sample size, thus avoiding loosening of the pipeline interface.

[0040] In summary, compared to current experimental studies that primarily consider steady-state thermo-hydraulic-mechanical coupling, dynamic thermo-hydraulic-mechanical coupling experiments often employ step-by-step loading modes, resulting in distorted environmental simulations. This invention organically integrates the temperature field, seepage field, and stress field into a single device. This device can simultaneously apply three dynamic coupling loads to the rock sample 4 within the same sample chamber 13, including temperature cycling, pore water pressure cycling, and axial-containment pressure mechanical stress cycling. This enables the sample to continuously experience the dynamic coupling of multiple thermo-hydraulic-mechanical fields under loading conditions, overcoming the time-consuming and inconsistent conditions of step-by-step experiments in existing technologies. This device can complete the low-temperature freeze-thaw, heating, pressurization and saturation, and mechanical loading processes of the sample in one go, significantly improving experimental efficiency. Simultaneously, the coupling loading of each field is carried out synchronously within the same system and can be cyclically applied, avoiding sample transfer between different devices and maintaining the continuity and controllability of the temperature field, pore pressure field, and stress field. This more closely resembles the actual loading state of rocks in in-situ environments, improving the authenticity and accuracy of the experimental results.

[0041] The device features wide-range precise temperature control and multi-channel servo loading capabilities, simulating the effects of extreme environments (deep high temperature and pressure or high-latitude freeze-thaw cycles) on rocks. It enables research on the mechanical responses of different types of rocks under varying temperature ranges or freeze-thaw cycles, overcoming the limitations of traditional triaxial testing systems. It is particularly suitable for simulating complex conditions such as freeze-thaw cycles in cold regions, water pressure fluctuations, and stress cycles, significantly improving experimental efficiency and data reliability. Thus, this invention boasts a rational structural design, comprehensive functions, and significantly reduces experimental preparation and conversion time, demonstrating strong practicality and feasibility. It is suitable for research and engineering testing needs in fields such as geotechnical engineering and underground engineering in cold regions.

[0042] It is worth mentioning that, in addition to achieving synchronous dynamic loading of thermo-hydraulic-mechanical multi-physics fields, the embodiments of this application can also switch to loading modes such as thermo-mechanical dual-field dynamic loading, water-mechanical dual-field dynamic loading, and thermo / hydraulic / mechanical single-field dynamic loading. The device can realize multiple loading modes such as mechanical stress loading, temperature-mechanical stress loading, pore water pressure-mechanical stress loading, and thermo-hydraulic-mechanical multi-physics field coupled loading within a single system, achieving continuously controllable experimental conditions from single-field to dual-field and then to multi-field. Experimenters can flexibly set experimental conditions according to research needs, expanding the experimental applicability and research depth of this device.

[0043] For example, during the test, the water-force loading conditions are kept constant, and the temperature applied by the heat loading component is dynamically adjusted. This method is suitable for simulating and testing the in-situ mechanical properties of slope rocks in high-altitude and cold regions under cyclic temperature conditions involving multi-physics coupling.

[0044] For example, during the test, the thermal loading conditions are kept constant, and the pore water pressure applied to the rock sample 4 by the pore water pressure loading component and the stress applied to the rock sample 4 by the force loading component are dynamically adjusted. This is suitable for simulating and testing the in-situ mechanical properties of reservoir slope rocks under the multi-physics coupling of circulating water and force conditions during reservoir rise and fall.

[0045] For example, during the test, dynamically adjusting the temperature applied by the heat loading component, dynamically adjusting the pore water pressure applied to the rock sample 4 by the pore water pressure loading component, and dynamically adjusting the stress applied to the rock sample 4 by the force loading component are suitable for simulating the in-situ mechanical properties of rocks on periglacial slopes under glacial circulation through multi-physics dynamic coupling.

[0046] Of course, in this embodiment, the thermal loading component, pore water pressure loading component and force loading component can be controlled individually or simultaneously to preset values ​​before the test begins, so as to achieve multi-field or single-field steady-state loading.

[0047] It should also be noted that the loading mode can be flexibly switched within the same device by opening and closing the pore water pressure loading component and the thermal loading component. In other embodiments, the thermal loading component can be omitted, in which case a dynamic water-mechanical dual-field coupled loading mode can be achieved within the same device. In other embodiments, the pore water pressure loading component can be omitted, in which case a dynamic thermal-mechanical dual-field coupled loading mode can still be achieved within the same device. This configuration reduces redundant components and piping connections, simplifies the system structure, and reduces control difficulty and maintenance costs in scenarios requiring only dual-field coupled dynamic loading. Compared to the traditional single-field loading mode or stepwise steady-state loading, rock sample 4 completes dual-field loading within the same device, and its experimental accuracy, efficiency, and system versatility are still superior to traditional testing equipment.

[0048] As a specific explanation of this embodiment, neither constant loading nor dynamic loading supports thermal cycling. Generally, rock mechanics testing machines, when performing mechanical loading, lack the capability for temperature regulation; they can only perform single heating or cooling, and loading is limited to constant temperature conditions. To achieve temperature regulation, dynamic water loading or dynamic force loading is impossible. A major reason for this is that traditional confining pressure media and liquid media cannot meet the requirements of thermal cycling loading. Commonly used confining pressure media are typically hydraulic oil or ethylene glycol-water solutions. The confining pressure servo pump 14 is connected to the sample chamber 13 via a high-pressure oil pipe, pressurizing or depressurizing the hydraulic oil. Temperature changes affect the viscosity and volume of the hydraulic oil (the hydraulic oil used in the confining pressure cylinder and in each pressure pump is the same), thereby altering the pressure transmission efficiency. Especially under low-temperature conditions, the confining pressure media and liquid media are prone to freezing, and the hydraulic oil has extremely poor fluidity, leading to instability and oscillations in loading speed or force control, thus making loading impossible in cryogenic temperature ranges or freeze-thaw cycles.

[0049] Therefore, this embodiment selects a liquid with a low coefficient of thermal expansion and a high bulk modulus. Liquids with these characteristics exhibit minimal viscosity changes with temperature, which can significantly reduce errors caused by temperature variations. The coefficient of thermal expansion can be in the range of 0.5 × 10⁻⁶. -3 / ℃~1.5×10 -3 The temperature range is ℃, and the bulk modulus can range from 1.0 GPa to 2.5 GPa. For example, both the confining pressure medium and the liquid medium are selected as silicone oil, which remains stable over a wide temperature range. Combined with... Figures 6-12 It can be seen that when silicone oil is selected as the confining pressure medium and liquid medium for the multi-physics field coupling synchronous dynamic loading test mentioned above in this invention, the obtained mechanical curve is very smooth, indicating that there is no error caused by temperature changes.

[0050] As an optional design in this embodiment, when thermal cycling is not required, this device can also support multiphase fluid percolation. Besides water, the injected liquid medium can also be gas or oil, to meet different research needs. The confining pressure medium can also be hydraulic oil or an ethylene glycol-water solution.

[0051] The cooling medium can be selected from a wide range and is not limited by thermal cycling. To balance fluidity and high heat exchange rate, anhydrous ethanol is preferred.

[0052] This embodiment illustrates the heat loading assembly. The heating element includes an electric heater surrounding the sample chamber 13; and / or, the cooling element includes a refrigerator, a cold bath 10, a cooling coil 12, and a cooling medium; the cooling coil 12 is arranged inside the sample chamber 13 and surrounds the rock sample 4; wherein, the cold bath 10 is integrated into the refrigerator and is in cyclic communication with the cooling coil 12, so that the cooling medium is cooled in the cold bath 10 and flows to the cooling coil 12, exchanges heat with the sample chamber 13, and then flows back into the cold bath 10.

[0053] In this embodiment, the cooling elements include a cold bath 10, a cooler 11, and a cooling coil 12 wound around the outer wall of the sample chamber 13. Both ends of the coil are connected to the cooler 11 and its associated cold bath 10. The cooler 11 cools the cooling medium in the cold bath 10 and circulates it to the cooling coil 12. The cooling medium is a low-freezing-point liquid refrigerant. The heating element is either an electric heater built into the sample chamber 13 or wound around the outer wall, uniformly heating the sample chamber 13 to the required temperature. Therefore, when loading is required at different temperature ranges, the cooling medium (ethanol or other antifreeze) is injected into the cold bath 10 and cooled to below -20°C by the cooler 11. The cooling medium is then driven by a circulating pump to flow through the cooling coil 12, continuously cooling the sample chamber 13 and the rock sample 4 inside. When heating is required, the cooling circulation is shut off and the heating device is activated to uniformly heat the sample chamber 13 to the required temperature, thereby achieving temperature cyclic control from cryogenic to high-temperature ranges within a single device.

[0054] This embodiment can also perform freeze-thaw cycle tests. The efficient cooling cycle of the cooling element can reduce the temperature of rock sample 4 to -20°C or even lower. During the freeze-thaw cycle test, rock sample 4 is first cooled under confining pressure to freeze the pore water, and then heated to thaw it. This cycle is repeated, and stress loading is superimposed to simulate the coupling effect of repeated freeze-thaw cycles and stress on rocks in cold regions. This achieves a unique function that is difficult to achieve with traditional heating furnaces and testing machines.

[0055] In some embodiments, the heating element may further include a resistance wire heating jacket, an infrared heating tube, and a heat transfer oil circulation pipe, etc. The cooling element may further include a refrigeration circulating water jacket, a thermoelectric cooling element, etc.

[0056] This embodiment illustrates a pore water pressure loading assembly. The pore water pressure loading assembly also includes a seepage servo pump 16 and a back pressure control valve. The seepage circuit includes an inlet pipe 9 and an outlet pipe 8. The seepage servo pump 16 is connected to the upper end of the rock sample 4 via the inlet pipe 9; the lower end of the rock sample 4 is connected to the back pressure control valve via the outlet pipe 8. The device also includes an upper permeable stone 31 and a lower permeable stone 32. The upper permeable stone 31 is disposed between the outlet of the inlet pipe 9 and the upper end of the rock sample 4, and the lower permeable stone 32 is disposed between the inlet of the outlet pipe 8 and the lower end of the rock sample 4.

[0057] In this embodiment, an independent seepage loop is set up to control the water pressure conditions inside the rock sample 4. The internal opening of the base 7 forms a downstream fluid channel, which is connected to the liquid outlet pipe 8; the internal through hole of the upper pressure head 2 serves as an upstream fluid channel, which is connected to the liquid inlet pipe 9. The upper permeable stone 31 and the lower permeable stone 32 are respectively set at both ends of the rock sample 4 to uniformly apply pore water pressure and prevent local stress concentration at the upper and lower ends of the rock sample 4.

[0058] During pore water loading, the inlet pipe 9 introduces the liquid medium output from the seepage servo pump 16 into the upper end of the rock sample 4. The upper permeable stone 31 and lower permeable stone 32 evenly distribute the liquid medium, adhering to both ends of the rock sample 4. This not only supports the rock sample 4 but also allows pore water to freely enter and exit while preventing the loss of fine particles. The outlet pipe 8 connects to the lower end of the rock sample 4 and is linked to the back pressure control valve to control the pore water discharge rate and downstream pressure. Compared to the traditional unidirectional application of pore water pressure, the seepage servo pump 16 and back pressure valve in this embodiment can apply a predetermined pore water pressure and upstream / downstream pressure difference, supporting the saturated seepage loading of the liquid medium onto the sample. For example, by adjusting the output pressure of the seepage servo pump 16 and the opening of the back pressure valve, the internal pore water pressure of the rock sample 4 can be precisely controlled, achieving a constant or variable upstream / downstream pressure difference to simulate a groundwater seepage environment.

[0059] During the experiment, the pore water pressure can be programmed to be applied synchronously with the axial pressure and confining pressure. For example, the water pressure can be increased or decreased during the loading of the rock sample to examine the seepage-stress coupling effect.

[0060] This embodiment illustrates a force loading assembly. The axial pressure loading element includes an axial pressure servo pump 15, a loading piston 1, and an upper pressure head 2 connected sequentially. At least a portion of the loading piston 1 extends axially through the container body into the sample chamber 13 and faces the upper pressure head 2, which presses against the rock sample 4. The axial pressure servo pump 15 is controlled to drive the loading piston 1 to compress the upper pressure head 2, thereby compressing the rock sample 4 through the upper pressure head 2; and / or, the confining pressure loading element includes a confining pressure servo pump 14 and an injection pipe 20 connected to each other. At least a portion of the injection pipe 20 extends through the container body into the sample chamber 13, and the confining pressure servo pump 14 injects or discharges confining pressure medium into the sample chamber 13 through the injection pipe 20.

[0061] In this embodiment, the axial pressure loading element includes a vertically arranged loading piston 1 and an upper pressure head 2 in movable contact with it. The loading piston 1 is mounted on the end cap of the container body, and the piston rod of the loading piston 1 passes through the end cap of the sample chamber 13 and faces the upper pressure head 2. The upper pressure head 2 directly contacts the top of the rock sample 4. The axial pressure servo pump 15 provides high-pressure oil to drive the loading piston 1, causing the loading piston 1 to reciprocate vertically within the sample chamber 13, thereby applying uniform axial pressure to the rock sample 4 within the sample chamber 13 through the upper pressure head 2. To ensure loading stability, a spherical contact seat can be provided between the loading piston 1 and the upper pressure head 2 to automatically correct minor alignment deviations and avoid uneven loading. The confining pressure servo pump 14 is connected to the sample chamber 13 through the injection pipe 20. The confining pressure servo pump 14 can inject or discharge confining pressure medium into the sample chamber 13 to adjust the confining pressure.

[0062] In some embodiments, the base 7 supports the rock sample 4 loaded into the sealing sleeve 5. Before the test begins, the base 7 is positioned below the loading piston 1 at a certain distance to facilitate the loading of the rock sample 4 into the sealing sleeve 5. The base 7 can be moved up and down via a lifting mechanism. When the test is ready to begin, the lifting mechanism moves the base 7 upward until the upper pressure head 2 at the upper end of the rock sample 4 comes into contact with the loading piston 1. At the same time, the base 7, the end cap, and the peripheral wall of the sample chamber 13 form a closed pressure chamber.

[0063] In traditional pressure loading systems, if the pressure pump itself has a small volume, its maximum output pressure and oil chamber volume are limited, making it difficult to meet the loading requirements of high pore water pressure, high confining pressure, or high axial pressure (such as above 100MPa). Conventional methods can only achieve this by increasing the volume of the pressure pump, but this results in larger equipment, significantly increased costs, and difficulty in controlling accuracy due to the excessively large pumping volume.

[0064] Preferably, a pump-side pressure gauge 22, a main switch 24, and a chamber-side pressure gauge 23 are sequentially installed on the hydraulic pipeline connecting the axial pressure servo pump 15 to the loading piston 1, the injection pipe 20 connecting the confining pressure servo pump 14 to the sample chamber 13, and the inlet pipe 9 connecting the seepage servo pump 16 to the sample chamber 13; and the axial pressure servo pump 15 is connected to the force loading oil tank 27 through the axial pressure oil circuit, the confining pressure servo pump 14 is connected to the force loading oil tank 27 through the confining pressure oil circuit, and the seepage servo pump 16 is connected to the pore water pressure loading oil tank through the seepage oil circuit; the hydraulic pipeline, the injection pipe 20, and the inlet pipe 9 are all connected to the corresponding oil tanks through oil pipe branches; a first branch switch 25 is installed on the axial pressure oil circuit, the confining pressure oil circuit, and the seepage oil circuit, and a second branch switch 26 is installed on the oil pipe branch.

[0065] In this embodiment, a pump-side pressure gauge 22 near the pump and a chamber-side pressure gauge 23 near the sample chamber 13 are respectively installed between the pump and the sample chamber 13, along with a main switch 24 located between the two pressure gauges. The pressure data of the chamber-side pressure gauge 23 is recorded in real time by a monitoring and control system to reflect the pressure inside the sample chamber 13 in real time. The pump may include at least one of a confining pressure servo pump 14, an axial pressure servo pump 15, and a seepage servo pump 16, and the pipeline connections of the three pumps to the sample chamber 13 are the same.

[0066] like Figure 5 As shown, Figure 5 The diagram shows the connection route between the sample chamber 13 and the external pipeline of the present invention. An example of the external pipeline is the injection pipe 20. Of course, the external pipeline can also be replaced by a hydraulic pipeline or an inlet pipe 9. For simplicity, this embodiment uses the confining pressure servo pump 14 as an example to illustrate the pipeline connection method; the axial pressure servo pump 15 and the seepage servo pump 16 can be referred to accordingly. Taking a target pressure of 100 MPa as an example, while the output pressure of a small-capacity pressure pump is typically 60 MPa, the following pumping method can be performed: 1. Turn on the main switch 24 and turn off the first sub-switch 25 and the second sub-switch 26 to discharge all the oil inside the confining pressure servo pump 14 into the sample chamber 13. At this time, the pressure in the entire injection pipe 20 is 60MPa, and the pressure readings of the pump side pressure gauge 22 and the chamber side pressure gauge 23 are 60MPa.

[0067] 2. Close the main switch 24 and open the second sub-switch 26 (the switch between the oil tank and the pipeline). The pressure reading of the pump-side pressure gauge 22 drops to 0 MPa, and the pressure reading of the chamber-side pressure gauge 23 is 60 MPa. After the oil medium is unloaded back into the oil tank and refilled, the pressure in the sample chamber 13 remains stable and unchanged.

[0068] 3. Open the first branch switch 25 (the switch between the oil tank and the pump), and the pump will be refilled with medium. Then close the first branch switch 25 and the second branch switch 26. The confining pressure servo pump 14 will fill the injection pipe 20 with medium, while keeping the main switch 24 closed. The pressure reading on the pump-side pressure gauge 22 will rise from 0 MPa to 60 MPa. Since no medium is injected into the sample chamber 13 during the pump-side pressurization process, only a small amount of oil medium is needed to bring the pressure of the entire injection pipe 20 back to 60 MPa.

[0069] 4. Reopen the main switch 24 to connect the confining pressure servo pump 14 to the sample chamber 13. At this time, the pump side pressure will be pushed from 60MPa to high pressure, and the liquid can continue to increase the pressure with a very small increment, which can increase the pressure in the injection pipe 20 from 60MPa to 100MPa.

[0070] It is evident that, since only a very small volume of liquid needs to be replenished during the pressure increase process, a small-capacity pressure pump can achieve pressure loading far exceeding its output limit, and can achieve very high pressure under the condition of stabilizing the pressure in the sample chamber 13, thereby improving the control accuracy and economy during the force loading process.

[0071] In conjunction with the above embodiments, the thermal loading component, the pore water pressure loading component, and the force loading component are respectively equipped with sensors. As a specific description of this embodiment: these sensors may include at least one of the following: temperature sensor 6, axial pressure sensor, axial displacement sensor 21, confining pressure sensor, radial deformation sensor, pore water pressure sensor, acoustic emission sensor 17, and ultrasonic detection component; wherein, temperature sensor 6 is used to measure the ambient temperature value and the temperature value inside the sample chamber 13; confining pressure sensor is used to measure the confining pressure value inside the sample chamber 13; axial pressure sensor is used to measure the axial load value applied by loading piston 1; axial displacement sensor 21 is used to measure the axial compression deformation of rock sample 4; radial deformation sensor is used to measure the expansion of rock sample 4 in the radial direction; pore water pressure sensor is used to measure the pore water pressure of rock sample 4 under saturated seepage loading; acoustic emission sensor 17 is used to collect elastic wave signals generated by internal cracks in rock sample 4; the ultrasonic detection component includes an ultrasonic transmitting probe 18 embedded in the upper pressure head 2 and an ultrasonic receiving probe 19 disposed at the bottom of the container body, used to collect ultrasonic signals of the rock as damage evolves.

[0072] In addition to the temperature sensor 6, axial pressure sensor, confining pressure sensor, and pore water pressure sensor mentioned above, this embodiment also includes a deformation measurement unit and an in-situ rock damage monitoring unit. The deformation measurement unit includes an axial displacement sensor 21 and a radial deformation sensor, used to cooperate with the loading of the axial pressure loading element and the confining pressure loading element. The axial displacement sensor 21 is installed at the position where the axial loading piston 1 is connected to the upper pressure head 2, and is used to measure the axial compression deformation of the rock sample 4; the radial deformation sensor is set on the inner wall of the sample chamber 13 or the sample surface, and is used to measure the expansion in the diameter direction of the sample.

[0073] The in-situ rock damage monitoring unit may include an acoustic emission sensor 17 and an ultrasonic testing assembly. The acoustic emission sensor 17 is mounted on the surface of the rock sample 4 or the inner wall of the sample chamber 13 via a coupling agent to capture elastic wave signals generated by cracks within the sample. The ultrasonic testing assembly includes an ultrasonic transmitting probe 18 (such as a first ultrasonic transducer) embedded in the upper pressure head 2 and an ultrasonic receiving probe 19 (such as a second ultrasonic transducer) disposed in the base 7. During the test, the ultrasonic transducer directionally emits and receives ultrasonic pulses penetrating the sample to measure changes in rock wave velocity and attenuation as damage evolves.

[0074] Therefore, compared to traditional rock mechanics testing equipment, the acoustic emission sensor 17 is installed on the outer wall of the confining pressure chamber. While this arrangement is convenient, during loading, the acoustic emission signal must pass through multiple layers of media, including the container wall, confining pressure medium, and sealing sleeve 5, resulting in a long propagation path. Elastic waves attenuate as they propagate through the interfaces of different materials, leading to signal distortion. To minimize signal attenuation and distortion, this embodiment directly attaches the acoustic emission sensor 17 to the rock sample surface using a coupling agent. This not only ensures a tight connection of the acoustic emission sensor 17 but also enables short-path, high-coupling signal acquisition, reducing energy attenuation and noise interference, and improving crack location accuracy. This method is suitable for high-fidelity real-time monitoring of the evolution of microcracks within rock masses under complex conditions such as high pressure, high temperature, and freeze-thaw cycles.

[0075] As a specific explanation of this embodiment, the upper pressure head 2 internally encapsulates two ultrasonic probes, one for emitting longitudinal waves (P-waves) and the other for emitting transverse waves (S-waves). The upper pressure head 2 also has internal fluid channels for pore fluid to pass through, thus combining ultrasonic monitoring and high-pressure seepage loading functions. The upper pressure head 2 is designed as a single, high-strength structure, with each probe having a package diameter of 13mm. The integrated high-pressure fluid channels within the upper pressure head 2 can withstand seepage pressures up to 60MPa. The upper pressure head 2 employs a solid structure, sufficient to withstand axial loads with a stiffness of no less than 1000MPa, ensuring the transducer's encapsulation does not weaken the device's mechanical rigidity. Therefore, while maintaining the ultrasonic transducer's seal, it can withstand pore water pressures of no less than 60MPa and large loads without deformation.

[0076] Furthermore, this device is equipped with a monitoring and control system connected to each sensor and actuator. The monitoring and control system includes a multi-channel data acquisition unit, a servo controller, and computer control software. The servo controller is electrically connected to actuators such as the axial pressure servo pump 15, the confining pressure servo pump 14, the seepage servo pump 16, heating elements, and cooling elements to synchronously control the application of axial pressure, confining pressure, pore water pressure, and temperature according to a pre-programmed loading path. The multi-channel data acquisition unit is connected to the sensors installed on the sample and the device to receive test data such as axial pressure, confining pressure, pore water pressure, displacement (strain), temperature, and acoustic emission signals in real time, which are then stored and displayed by the computer.

[0077] For example, the monitoring and control system is connected to temperature sensor 6. During the thermal loading process, temperature sensors 6, distributed inside and outside the sample chamber 13, monitor the temperature of the sample and medium in real time and feed it back to the monitoring and control system. The monitoring and control system automatically adjusts the output of the refrigerator or heater according to the sensor deviation to achieve precise and stable temperature control with an accuracy of ±0.1℃. The force loading component is equipped with force sensors and displacement sensors, which are used to measure axial load, confining pressure, and piston displacement / sample shortening, respectively, and feed them back to the monitoring and control system to achieve precise closed-loop control. The monitoring and control system is connected to acoustic emission sensor 17 and ultrasonic transducer to synchronously record acoustic emission events and changes in ultrasonic wave propagation characteristics, achieving real-time monitoring of the entire process of rock damage evolution. The monitoring and control system is connected to deformation measurement units (such as axial displacement sensor 21 and radial deformation sensor), which can realize control modes such as constant strain rate loading and constant strain loading based on deformation sensor feedback to improve the stability and data accuracy of brittle rock loading.

[0078] In conjunction with the above embodiments, axial load, confining pressure, and pore water pressure loading are each controlled by independent servo hydraulic pumps. The minimum flow rate adjustment accuracy of the seepage servo pump 16 and the confining pressure servo pump 14 is no higher than 0.001 mL / min, and the pressure control accuracy is better than ±0.01 MPa. The axial pressure servo pump 15 has a maximum flow rate of over 20 mL / min and a programmable multi-segment loading function. Through the coordinated control of the above-mentioned high-precision servo loading system, the device can automatically load any path for each loading amount during the test, including constant loading, cyclic loading, and segmented progressive loading modes, meeting the precise control requirements of loading rate and path for complex thermo-hydraulic-mechanical coupling tests.

[0079] In summary, the dynamic thermo-hydraulic-mechanical coupling test device of this invention mainly includes a sample chamber 13, an axial pressure loading element, a confining pressure loading element, a pore water pressure loading assembly, a thermal loading assembly, and a monitoring and control system. It has the following advantages: Multi-field synchronous loading: The device can simultaneously apply three dynamic coupled loads to the rock sample 4 within the same pressure chamber, including temperature cycling (range -20℃ to 200℃), pore water pressure cycling, and axial-containment mechanical stress cycling. The synchronous and coordinated application of each load and arbitrary programmable control are achieved through a monitoring and control system. This allows for continuous simulation of the entire process of thermo-mechanical and hydro-mechanical coupling of the sample under loading conditions.

[0080] Wide-range, high-precision temperature control: The temperature control system covers a range from cryogenic to high-temperature conditions, and can adjust the sample temperature from -20℃ to 200℃. This system can rapidly cool to deep cryogenic temperatures to meet the requirements of freeze-thaw cycle tests, and can also heat to 200℃ to meet high-temperature test conditions, covering a wide temperature range required for rock mechanics research.

[0081] Independent servo multi-pump loading: Axial load, confining pressure, and pore water pressure loading are each controlled by an independent servo hydraulic pump. The axial pressure loading element applies axial force by driving a piston through a servo pump, while the confining pressure loading element and pore water pressure loading assembly are respectively controlled by servo pumps to regulate the hydraulic pressure of the confining pressure chamber and the seepage circuit. The three servo control loops operate independently yet collaboratively, allowing users to preset arbitrarily complex loading paths and rates. For example, it is possible to program the confining pressure and axial pressure to change cyclically over time, and simultaneously adjust the pore water pressure and temperature to simulate real-world working conditions. Each servo loading unit has high-resolution and high-precision pressure / flow control capabilities, can stably maintain pressure, and supports long-term continuous loading (continuous coupled loading tests ≥800h are possible).

[0082] The device also features strain control: a built-in specimen deformation measurement system, including a dual-channel axial displacement sensor and a radial deformation sensor, can monitor the axial and radial deformation of the specimen in real time. The monitoring and control system can perform closed-loop control based on the strain signal, realizing loading modes such as axial displacement control or strain rate control, ensuring the stability of the brittle specimen loading process and the accuracy of data acquisition.

[0083] Multi-method damage monitoring: This device has reserved sensing interfaces and integrates multiple monitoring devices to achieve full-process observation of rock damage evolution. An acoustic emission sensor 17 can be installed on the outer wall of the sample to monitor transient elastic wave signals generated by the development of microcracks inside the sample. An ultrasonic transducer is embedded in the upper indenter 2, which can periodically excite and receive P-wave and S-wave ultrasonic pulses penetrating the sample during loading, thereby measuring the change in rock wave velocity as damage evolves. These in-situ non-destructive testing methods can operate synchronously with loading, assisting in identifying the stages of crack initiation and propagation inside the sample. Thus, the accompanying acoustic emission, ultrasonic, and other monitoring methods enable real-time observation of the entire process from loading to failure of the rock, providing rich evidence for revealing the rock damage mechanism.

[0084] The technical solution of the present invention will be described in more detail below with reference to specific embodiments and accompanying drawings.

[0085] As unique geological formations directly affected by glacial activity, periglacial slopes often pose a significant threat to downstream watersheds due to their instability, serving as the starting point of glacial hazard chains. Therefore, a deep understanding of the damage mechanisms of periglacial slope rock masses is crucial for predicting and preventing glacial hazard chains. The cycles of glacial advancement, erosion, and retreat lead to continuous dynamic changes in the temperature field (heat), seepage field (water), stress field (force), and their boundary conditions, affecting depths of tens of meters, far exceeding the shallow environments considered in conventional freeze-thaw cycles in cold regions. Therefore, research on the damage mechanisms of periglacial slope rock masses must consider the unique dynamic thermal (freeze-thaw cycle), water (hydraulic pressure cycle), and force (stress cycle) environment.

[0086] Correspondingly, regarding the second aspect, please refer to Figure 6 As shown, Figure 6 This embodiment provides a flowchart of the steps for a dynamic thermo-hydraulic-mechanical coupling test device suitable for periglacial slope rocks. The present invention also provides a dynamic thermo-hydraulic-mechanical coupling test method suitable for periglacial slope rocks, aiming to simulate the actual working conditions of rock mass unloading, temperature increase, and water pressure decrease during glacier retreat, and rock mass loading, temperature decrease, and water pressure increase during glacier advance. Utilizing the dynamic thermo-hydraulic-mechanical coupling test device provided in the first aspect of the present invention, the thermo-hydraulic-mechanical boundary conditions are synchronously realized on a rock mechanics testing machine. The method includes the following steps: S1. Load the rock sample 4 into the sealing sleeve 5 inside the sample chamber 13.

[0087] S2. Activate the confining pressure loading element to apply confining pressure to rock sample 4.

[0088] S3. In each cycle, the pore water pressure loading component is activated to increase the permeation pressure of rock sample 4; then the permeation pressure of rock sample 4 is reduced by servo control to simulate the ice edge slope rock under water pressure circulation conditions.

[0089] S4. In each cycle, the cooling element is turned on to lower the temperature of the sample chamber 13 and the rock sample 4, causing the liquid medium to freeze; then the cooling element is turned off and the heating element is turned on to raise the temperature of the sample chamber 13 and the rock sample 4, causing the liquid medium to melt, so as to simulate the ice edge slope rock under freeze-thaw cycle conditions.

[0090] S5. In each cycle, the axial pressure loading element is activated to apply axial pressure to the rock sample 4; then the axial pressure of the rock sample 4 is reduced by servo control to simulate the rock on the ice edge slope under stress cycle conditions.

[0091] S6. Record the test data of rock sample 4 during each cycle of loading. The test data shall include at least temperature, pore water pressure and pressure load, in order to simulate and test the in-situ mechanical response performance of the rock on the peri-ice slope in the coordinated and synchronous process of freeze-thaw cycle-water pressure cycle-stress cycle.

[0092] It should be noted that, for the method embodiments, the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps may be performed in other orders or simultaneously.

[0093] The above method embodiments are basically similar to the device embodiments, so the description is relatively simple. For relevant details, please refer to the description of the device embodiments.

[0094] During the experiment, the operator can use a graphical user interface (GUI) on a computer to set loading programs for the axial pressure servo pump 15, confining pressure servo pump 14, seepage servo pump 16, and temperature control system. The control software allows for setting multi-stage loading processes, such as: first applying confining pressure to the initial value, then increasing the axial deviatoric stress and pore water pressure at a set rate while simultaneously decreasing the temperature, maintaining this for a period of time, and then reversing the adjustment of parameters, repeating this cycle. Each loading channel can be programmed with more than 20 loading paths, enabling flexible definition of complex cyclic loading schemes. During the test run, the system automatically coordinates and controls the servo pumps and temperature control unit to load synchronously according to the preset scheme, and records multi-channel data in real time, including up to 20 curves such as time, axial load, axial displacement (or strain), confining pressure, pore water pressure, sample temperature, and ambient temperature. The high sampling rate of the data acquisition module ensures the capture of every load change and sudden rock response event (such as acoustic emission signal triggering). All data is stored in the computer for subsequent analysis to accurately assess the deformation, strength, and damage evolution characteristics of the rock in the thermo-hydraulic-mechanical cycle.

[0095] Strain Measurement and Loading Modes: Since the deformation response of rock under multi-field coupling conditions is a crucial indicator for damage evaluation, two axial displacement sensors 21 with identical strokes are installed at the piston and upper pressure head 2, forming a dual-channel redundant measurement to accurately determine the axial deformation of the specimen. In the radial direction, radial deformation sensors (such as circumferential displacement sensors or strain gauge arrays) are arranged near the specimen within the specimen chamber 13 to monitor the expansion / contraction changes in the radial direction of the specimen. After these sensors are connected to the control system, in addition to conventional stress control and displacement control loading modes, advanced loading modes such as axial strain control and constant confining pressure-axial strain control can be implemented. For example, constant stress control can be used in creep tests, while constant strain rate control can be switched in rock fracture process tests to prevent instability. The multi-mode loading selection provided by this invention allows it to adapt to the requirements of different types of rock tests (such as strength tests, creep tests, cyclic fatigue tests, etc.), improving the operability and safety of the tests.

[0096] Damage monitoring and multi-field coupling test procedure: As previously described, the device's built-in and scalable sensor network enables continuous monitoring of rock damage throughout the test. Please refer again. Figure 2 As shown, one or more acoustic emission sensors 17 are pre-attached to the sidewall of rock sample 4 (tightly bonded to the rock sample surface with a coupling agent). The sensors are connected to a high-speed data acquisition system, which can capture stress wave signals generated by micro-crack events inside the rock. During the test, whenever a microcrack propagates in the sample, it is accompanied by transient elastic waves (AE events). The system records the occurrence time, amplitude, frequency, and other information of the events, and analyzes the damage accumulation based on this information.

[0097] Meanwhile, the device utilizes an ultrasonic transducer embedded in the upper pressure head 2 to perform ultrasonic detection: the control system periodically triggers the transducer to emit P-wave and S-wave ultrasonic pulses of a preset frequency, which are transmitted through the rock sample to the ultrasonic receiving probe 19 at the base 7 (another transducer installed symmetrically at the base 7 serves as the receiver), and the propagation time and amplitude are measured. From the changes in ultrasonic propagation speed and attenuation, the loss of rock stiffness and the development of fractures can be inferred.

[0098] Using glacier advance and retreat as a prototype, a dynamic thermo-hydraulic-mechanical coupled cyclic loading test was conducted on rock specimen 4 using the test apparatus described in this application. Different number of cycles and control group tests were set in the test (a control group undergoing only dynamic loading and unloading cycles and a control group undergoing only dynamic thermo-hydraulic coupled cycles). Specimens undergoing dynamic loading and unloading cycles were numbered M, those undergoing dynamic thermo-hydraulic coupled cycles were numbered TM, and those undergoing dynamic thermo-hydraulic coupled cycles were numbered THM. Rock specimen 4 was named the loading mode-cycle number; for example, the rock specimen subjected to 4 cycles of loading in the THM group was named THM-4.

[0099] The specific operating steps are as follows: ① Seal and fix the sample inside the device; ② Fill sample chamber 13 with oil; ③ Adjust the loading piston 1 to contact the sample; ④ Increase the confining pressure to 10 MPa while simultaneously lowering the temperature to 10℃; ⑤ Increase the deviatoric stress to 60 MPa while simultaneously lowering the temperature to -10℃ and increasing the water pressure to 2 MPa; ⑥ After loading, maintain the stress state, and unload the next day, reducing the deviatoric stress to 0 MPa while simultaneously increasing the temperature to 10℃ and decreasing the water pressure to 0 MPa. Repeat this process for different numbers of cycles to represent different glacier advances and retreats. The M control group is always kept at a temperature of 20℃ (room temperature) and a water pressure of 0 MPa; the TM control group is always kept at a water pressure of 0 MPa.

[0100] The performance test results are as follows: Figures 7-12 The test data for samples numbered M-6, TM-6 and THM-4 are given in detail.

[0101] Figure 7 In the middle: (a) is the axial stress curve of rock sample M-6; (b) is the curve of axial strain and circumferential strain of rock sample M-6. Figure 8 In the middle: (a~f) are the loading creep curves and their second derivative curves for a single cycle of the M-6 rock sample, respectively. Figure 7 A total of six cycles were shown to determine the time to enter steady-state creep.

[0102] Figure 9 In the middle: (a) is the axial stress curve of the TM-6 rock sample; (b) is the axial strain and circumferential strain curve of the TM-6 rock sample. Figure 10 In the middle: (a~f) are the loading creep curves and their second derivative curves for a single cycle of the TM-6 rock sample, respectively. Figure 9 A total of six cycles were shown to determine the time to enter steady-state creep.

[0103] Figure 11 In the middle: (a) is the axial stress curve of the THM-4 rock sample; (b) is the axial strain and circumferential strain curve of the THM-4 rock sample. Figure 12 In the middle: (a~e) are the single-cycle loading creep curves and their second derivative curves for the THM-4 rock samples, respectively. Figure 11 A total of five cycles were shown to determine the time to enter steady-state creep.

[0104] It can be seen that, Figure 7 (a) Figure 9 (a) and Figure 11 Figure (a) describes the cyclic curves under different coupling modes of force, temperature, and water pressure during the experiment. Figure 7 (b) Figure 9 (b) and Figure 11 Comparing with (b) in the previous section, considering only the M or TM conditions, the rock sample can be cycled up to 6 times without damage; when considering the THM condition, the number of cycles is at most 4, and the rock sample fails on the 5th cycle. Therefore, compared with a single factor (thermal / hydraulic / mechanical), THM coupling accelerates damage development, and the number of initial damage cycles required for rock sample failure drops sharply.

[0105] Figure 8 (a~f) Figure 10 (a~f) and Figure 12 Figures (a~e) show the axial strain curves of rock samples M-6, TM-6, and THM-4 at each cyclic loading stage, respectively. Using these curves, the time required for the rocks to enter the stable creep stage and the stable creep rate for each cycle were obtained. Due to data limitations... Figure 12The confidence level of (a) is low. From the creep curve morphology, the duration of rock decay creep is short, and it shows a decreasing trend with increasing cycle number. Specifically, the time required for the M-6 rock sample to enter the stable creep stage under 1-6 cycle conditions were 14.01, 12.00 (low confidence), 10.12, 8.75, 8.44, and 8.28 h, respectively. The time required for the TM-6 rock sample to enter the stable creep stage under 1-6 cycle conditions were 11.65, 8.52, 7.36, 6.95, 6.36, and 6.38 h, respectively. The time required for the THM-4 rock sample to enter the stable creep stage under 1-4 cycle conditions were 13.19 (low confidence), 7.30, 6.48, and 5.45 h, respectively. Under the same number of cycles, the THM-4 rock sample required a shorter time to enter the stable creep stage. The transition from decay creep to stable creep in rocks is generally not obvious, but there are relatively clear signs before material failure, namely, the inability to stabilize after a short period of time. A faster entry into the stable creep stage indicates that the material is closer to failure. Therefore, THM coupling promotes the progressive failure process.

[0106] Therefore, the test apparatus provided in this application can provide a realistic multi-field coupled test environment for in-situ testing of the mechanical properties of rocks, which significantly improves the feasibility and data reliability of rock thermo-hydraulic-mechanical coupled tests.

[0107] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

Claims

1. A dynamic thermo-hydraulic-mechanical coupling test device, characterized in that, The apparatus includes a container body surrounding a sample chamber for containing a rock sample; and integrated onto the container body: A heat loading assembly includes a heating element and a cooling element. The heating element includes an electric heater surrounding the sample chamber, and the cooling element includes a refrigerator, a cold bath, and a cooling coil connected in sequence. A cooling medium flows between the cold bath and the cooling coil. The heating element and the cooling element operate individually or alternately to simulate rocks under a wide temperature range or freeze-thaw cycles. A pore water pressure loading assembly includes a seepage servo pump, a back pressure control valve, and an inlet pipe and an outlet pipe through which a liquid medium flows. The seepage servo pump is connected to the upper end of the rock sample through the inlet pipe, and the lower end of the rock sample is connected to the back pressure control valve through the outlet pipe, so as to establish a saturated seepage loading with pore water pressure. The force loading assembly includes an axial pressure loading element and a confining pressure loading element. The axial pressure loading element includes an axial pressure servo pump, a loading piston, and an upper pressure head connected in sequence, with the upper pressure head pressing against the rock sample. The axial pressure servo pump drives the loading piston to move towards or away from the upper pressure head to apply dynamic axial pressure to the rock sample through the upper pressure head. The confining pressure loading element includes a confining pressure servo pump and an injection pipe connected in series. The injection pipe communicates with the sample chamber, and the confining pressure servo pump drives the injection pipe to inject or discharge confining pressure medium into the sample chamber to apply dynamic confining pressure to the rock sample. The sample chamber is equipped with a sealing sleeve that covers the rock sample to isolate the confining pressure medium and the liquid medium. The confining pressure medium and the liquid medium are liquids with low thermal expansion coefficients and high bulk moduli to support the dynamic loading of the rock under the wide temperature range or freeze-thaw cycle conditions.

2. The dynamic thermo-hydraulic-mechanical coupling test device according to claim 1, characterized in that, The sealing sleeve is a hollow tubular body with openings at the top and bottom and a hollow interior. The upper opening of the sealing sleeve is sealed and bonded to the upper pressure head, and the lower opening is sealed and bonded to the base of the container body. An adhesive layer is filled between the hollow inner wall and the rock sample to isolate the liquid medium between the sealing sleeve and the rock sample.

3. The dynamic thermo-hydraulic-mechanical coupling test device according to claim 1, characterized in that, The device further includes: The data acquisition component includes an in-situ rock damage monitoring unit, which includes an acoustic emission sensor and an ultrasonic detection component. The acoustic emission sensor is attached to the surface of the rock sample or the inner wall of the sample chamber by a coupling agent, and is used to collect elastic wave signals generated by internal cracks in the rock sample over a short distance. The ultrasonic testing component includes an ultrasonic transmitting probe and an ultrasonic receiving probe. The ultrasonic transmitting probe is embedded in the upper pressure head, and the ultrasonic receiving probe is disposed on the base of the container body for collecting ultrasonic signals penetrating the rock sample.

4. The dynamic thermo-hydraulic-mechanical coupling test device according to claim 3, characterized in that, The upper pressure head includes a high-strength solid body, and the ultrasonic transmitting probe is encapsulated inside the upper pressure head. A fluid channel is also provided inside the upper pressure head, and the fluid channel is connected to the liquid inlet pipe to simultaneously support ultrasonic detection and high water pressure seepage loading.

5. The dynamic thermo-hydraulic-mechanical coupling test device according to claim 2, characterized in that, The device also includes an upper permeable stone and a lower permeable stone. The upper permeable stone is disposed between the upper opening of the sealing sleeve and the upper end of the rock sample, and the lower permeable stone is disposed between the lower opening of the sealing sleeve and the lower end of the rock sample.

6. The dynamic thermo-hydraulic-mechanical coupling test device according to claim 1, characterized in that, The hydraulic pipeline connecting the axial pressure servo pump to the loading piston, the injection pipe connecting the confining pressure servo pump to the sample chamber, and the inlet pipe connecting the permeation servo pump to the sample chamber are all sequentially equipped with a pump-side pressure gauge, a main switch, and a chamber-side pressure gauge; and, The axial pressure servo pump is connected to the force loading oil tank through the axial pressure oil circuit, and the confining pressure servo pump is connected to the force loading oil tank through the confining pressure oil circuit. The seepage servo pump is connected to the pore water pressure loading oil tank through the seepage oil circuit. The hydraulic lines, the injection lines, and the inlet lines are all connected to the corresponding oil tanks via branch lines. A first branch switch is provided on the axial pressure oil circuit, the confining pressure oil circuit, and the seepage oil circuit, and a second branch switch is provided on the oil pipe branch.

7. The dynamic thermo-hydraulic-mechanical coupling test device according to claim 2, characterized in that, The liquid medium and the confining pressure medium include silicone oil; and / or, the cooling medium includes at least anhydrous ethanol.

8. The dynamic thermo-hydraulic-mechanical coupling test device according to claim 1, characterized in that, The cooling coil is arranged inside the sample chamber and surrounds the rock sample; wherein, the cold bath is integrated on the refrigerator and is circulated in communication with the cooling coil, so that the cooling medium is cooled in the cold bath and flows to the cooling coil, exchanges heat with the sample chamber and then flows back to the cold bath.

9. A dynamic thermo-hydraulic-mechanical coupling test device according to claim 3, characterized in that, The data acquisition component also includes: A temperature sensor is used to measure the temperature value inside the sample chamber; An axial pressure sensor is used to measure the axial load applied by the loading piston. A confining pressure sensor is used to measure the confining pressure value inside the sample chamber; An axial displacement sensor is used to measure the axial compressive deformation of the rock sample. A radial deformation sensor is used to measure the amount of expansion of the rock sample in the radial direction; A pore water pressure sensor is used to measure the pore water pressure of the rock sample under saturated seepage loading. The axial displacement sensor is provided in two parts, and the two axial displacement sensors are symmetrically mounted on the loading piston to form a dual-channel redundant measurement. The device also includes: The monitoring and control system is connected to the axial pressure servo pump, confining pressure servo pump, seepage servo pump, heating element and cooling element respectively, to apply axial load, confining pressure, pore water pressure and temperature according to the preset loading path; The monitoring and control system is also connected to the data acquisition component to receive and display multi-channel sensor data acquired by the data acquisition component during the loading process; the multi-channel sensor data includes at least one of ambient temperature value, temperature value, confining pressure value, axial load value, axial compression deformation, expansion, pore water pressure, elastic wave signal and ultrasonic signal. Based on the multi-channel sensor data, the corresponding axial pressure servo pump, confining pressure servo pump, seepage servo pump, heating element, and cooling element are controlled to be on the target loading path.

10. A dynamic thermo-hydraulic-mechanical coupling test method suitable for periglacial slope rocks, characterized in that, The method, relying on the dynamic thermo-hydraulic-mechanical coupling test apparatus as described in any one of claims 1-9, is used to test the in-situ mechanical response performance of periglacial slope rocks under thermo-hydraulic-mechanical coupling cyclic loading, and includes: The rock sample is loaded into the sealed sleeve inside the sample chamber; Activate the confining pressure loading element to apply confining pressure to the rock sample; During each cycle, the pore water pressure loading component is activated to dynamically adjust the pore water pressure applied to the rock sample, so as to simulate the ice edge slope rock under water pressure circulation conditions. In each cycle, the cooling element is turned on to lower the temperature of the sample chamber and the rock sample, causing the liquid medium to freeze; then the cooling element is turned off and the heating element is turned on to raise the temperature of the sample chamber and the rock sample, causing the liquid medium to melt, thus simulating the ice edge slope rock under freeze-thaw cycle conditions. In each cycle, the axial compression loading element is activated to apply dynamic axial pressure to the rock sample to simulate the rock on the periglacial slope under stress cycling conditions. Record the test data of the rock sample under each cycle of thermo-hydraulic-mechanical coupled synchronous dynamic loading. The test data includes at least temperature, pore water pressure and pressure load, in order to test the in-situ mechanical response performance of the rock on the periglacial slope under thermo-hydraulic-mechanical coupled cyclic loading.

Images