A triaxial apparatus for realizing the coupling of static load and high-frequency cyclic load

Abstract

The present invention relates to a triaxial instrument for realizing the coupling effect of static load and high-frequency cyclic load, including a loading system and a measuring unit, wherein the loading system includes a loading frame, a reaction frame, a lifting platform arranged on the loading frame and below the reaction frame, a triaxial chamber arranged on the lifting platform, a triaxial chamber top cover arranged on the top of the triaxial chamber, a voice coil motor arranged below the reaction frame, a loading rod connected to the voice coil motor and passing through the triaxial chamber top cover, and an air pressure source connected to the inside of the triaxial chamber, and the measuring unit includes a pressure measurement system, an axial force measurement system, an acceleration measurement system, a displacement measurement system, a volume measurement system, and an acquisition and analysis system. Compared with the prior art, the present invention can realize the coupling effect of static load and high-frequency cyclic load, can realize 150Hz high-frequency low-amplitude cyclic load, and the cycle time or number can be determined according to needs and the heating condition of the voice coil motor; and realizes accurate control of low stress amplitude as low as 0.5kPa, and its error is less than 0.1kPa.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering testing equipment and environmental vibration engineering, and relates to a triaxial instrument for realizing the coupling effect of static load and high-frequency cyclic load. Background Art

[0002] As my country's regional economy is developing rapidly, the traffic volume between regions has increased significantly, and the number of high-speed railways and highways is growing rapidly. The subgrade soil is subject to long-term high-frequency vibration of traffic loads, especially the high-speed railway is facing a trend of speed increase, towards 400km / h or even higher. Therefore, the long-term service performance of the subgrade soil under the high-frequency cyclic load will directly affect the safe operation and comfort guarantee of high-speed trains. Based on its high-frequency vibration characteristics, the dynamic response of the subgrade soil under the track increases with the depth of the soil, and the dynamic stress amplitude decays sharply. Under the action of high-frequency, low-amplitude dynamic loads, the soil can produce a sharp decay in shear strength, a sharp increase in pore water pressure, and a sharp development in deformation.

[0003] The existing geotechnical dynamic property testing equipment mainly includes dynamic single shear apparatus, conventional vibration triaxial apparatus, resonant column apparatus, vibration torsion shear triaxial apparatus, etc. The functions of these devices are relatively limited, especially the conventional vibration triaxial apparatus, which can currently load at a frequency of about 10Hz. In addition, the commonly used confining pressure loading method for indoor tests is water pressure loading, especially the friction between the loading rod and the top cover of the triaxial chamber is large. During high-frequency vibration, the friction between the two increases sharply, resulting in a significant reduction in the output power. The general volume strain sensor converts the volume strain by compensating for the change in pore water pressure. Due to the large cross-sectional area of ​​the inner cavity of the servo system, the small volume change caused by vibration can hardly be monitored by the water pressure servo. Therefore, under the action of high-frequency and low-amplitude vibration, it is difficult for conventional instruments to meet the experimental requirements of the above-mentioned high-frequency cyclic loading conditions. Summary of the invention

[0004] The purpose of the present invention is to provide a triaxial instrument that realizes the coupling of static load and high-frequency cyclic load, which can achieve high loading frequency (such as 150Hz), dynamic stress amplitude (generally not higher than 6kPa), high energy input (friction dissipation is minimized), high-precision body strain sensor, and low operating cost, and can solve the problems of instrument function limitations and insufficient detection accuracy existing in existing rock and soil dynamic properties testing equipment.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A triaxial instrument for realizing the coupling of static load and high-frequency cyclic load, the triaxial instrument comprises a loading system and a measuring unit adapted to the loading system, the loading system comprises a loading frame, a reaction frame arranged on the loading frame, a lifting platform arranged on the loading frame and located below the reaction frame, a triaxial chamber arranged on the lifting platform and used to place a sample, a triaxial chamber top cover arranged on the top of the triaxial chamber, a voice coil motor arranged below the reaction frame, a loading rod connected to the voice coil motor and passing through the triaxial chamber top cover, and an air pressure source connected to the inside of the triaxial chamber, the measuring unit comprises a pressure measurement system, an axial force measurement system, an acceleration measurement system, a displacement measurement system, a volume measurement system, and an acquisition and analysis system. The loading rod is responsible for transferring the load. The loading system can realize static loading and dynamic loading. Its characteristics are that it can realize high-frequency cyclic loading according to the static shear rate and axial stress conditions. The control of axial stress is achieved by controlling the height of the lifting platform on the loading frame. The confining pressure is provided by the triaxial chamber to achieve a higher static stress level. The dynamic load is applied by the voice coil motor, which applies the dynamic load to the sample through the high-frequency movement of the internal mobile permanent magnet. The loading system has a more efficient and accurate high-frequency dynamic load loading method, thereby obtaining higher measurement accuracy.

[0007] Furthermore, the axial force measurement system includes a high-frequency load sensor disposed between the reaction frame and the voice coil motor, and the acquisition and analysis system is electrically connected to the high-frequency load sensor and the voice coil motor, respectively. Preferably, the high-frequency load sensor is fixed to the reaction frame by bolts, the voice coil motor is fixed to the high-frequency load sensor by bolts, and the loading rod is fixed to the bottom of the voice coil motor by bolts. The acquisition frequency can be adjusted as needed to achieve the axial stress acquisition of the sample.

[0008] Furthermore, the sample is covered with a latex film, a sample cap is provided on the top, and the bottom of the loading rod is in contact with the sample cap.

[0009] Furthermore, a steel ball guide sleeve is provided between the top cover of the triaxial chamber and the loading rod, and a plurality of steel balls matching the loading rod are provided in the steel ball guide sleeve. The steel balls not only reduce the friction between the loading rod and the top cover of the triaxial chamber, but also form an air film during the flow of air during the high-frequency load vibration application process, and can also greatly reduce the energy dissipation of the vibration of the voice coil motor. In addition, this loading method can also avoid the increase in friction of the device caused by the viscosity of water generated by high-frequency dynamic loading due to conventional water pressure.

[0010] Furthermore, a first high-pressure transparent tube is provided between the air pressure source and the top of the sample, a second high-pressure transparent tube is provided between the air pressure source and the bottom of the sample, a third high-pressure transparent tube is provided between the air pressure source and the inner cavity of the triaxial chamber, and valves are provided on the first high-pressure transparent tube, the second high-pressure transparent tube, and the third high-pressure transparent tube. The valve includes a pressure regulating valve, a switch valve, etc.

[0011] Furthermore, the pressure measurement system includes a confining pressure sensor arranged on the third high-pressure transparent tube and a pore water pressure sensor arranged on the second high-pressure transparent tube, the volume measurement system includes a body strain sensor arranged on the first high-pressure transparent tube, and the acquisition and analysis system is electrically connected to the confining pressure sensor, the pore water pressure sensor, and the body strain sensor, respectively. The air pressure source is connected to the triaxial chamber and the sample through the high-pressure transparent tube. By using the confining pressure sensor and the pore water pressure sensor, the valve on the first high-pressure transparent tube can be closed under the condition of non-drainage test to achieve high-precision measurement of pore water pressure. The body strain sensor can achieve high-precision monitoring of the volume change of the sample. The drainage volume of the soil changes slightly under high-frequency cyclic loads, so high-precision measuring instruments are required.

[0012] Furthermore, the acceleration measurement system includes a transfer rod arranged on the loading rod and an acceleration sensor arranged on the transfer rod, and the acquisition and analysis system is electrically connected to the acceleration sensor.

[0013] Furthermore, the displacement measurement system includes a laser displacement sensor disposed on the top cover of the triaxial chamber, and the acquisition and analysis system is electrically connected to the laser displacement sensor. The laser displacement sensor measures the high-frequency displacement response of the sample during static shear and due to the vibration of the voice coil motor.

[0014] Furthermore, the acquisition and analysis system includes a high-frequency data acquisition instrument, which is electrically connected to the voice coil motor, the pressure measurement system, the axial force measurement system, the acceleration measurement system, the displacement measurement system, and the volume measurement system. The single-channel maximum acquisition frequency of the high-frequency data acquisition instrument can reach 5KHz.

[0015] Furthermore, the acquisition and analysis system also includes a computer electrically connected to the high-frequency data acquisition instrument. The high-frequency data acquisition instrument is connected to the computer via a high-bandwidth optical fiber, and the computer can display, store and analyze the data.

[0016] In the present invention, the loading system can realize synchronous coupling loading of static load and high-frequency cyclic load, the control of static load is realized by adjusting axial stress, confining pressure and back pressure, the static load is jointly controlled by the lifting platform, the three-axis chamber, the loading rod, the voice coil motor, the high-frequency load sensor, the reaction frame and the friction between the loading rod and the top cover of the three-axis chamber, the axial stress is realized by controlling the lifting rate of the three-axis chamber by a computer, the confining pressure and the back pressure are provided by an air pressure source, the size of the confining pressure and the back pressure is controlled by a pressure regulating valve, the air pressure source applies air pressure to the sample through the three-axis chamber by providing air pressure and adjusting the pressure regulating valve, thereby realizing a higher axial static stress level; the high-frequency cyclic load generates a high-frequency cyclic load by controlling the input current of the voice coil motor by a computer, and the driving force acts on the sample in the form of a dynamic load, thereby realizing the coupling loading of static load and high-frequency cyclic load, and has the advantages of wide load frequency and amplitude adjustment range, high measurement accuracy, simple operation and the like.

[0017] Among them, the static load acts on the sample through the confining pressure and the back pressure. The sample has a certain shear strength. The triaxial chamber moves upward at a fixed rate, so that the sample is subjected to triaxial compression and shear, thereby achieving the target strength; the dynamic load is generated by the low inertia Ampere force between the mobile permanent magnet and the fixed coil inside the voice coil motor. The dynamic load generated has the characteristics of high frequency and low amplitude. Small steel balls are set laterally on the steel ball guide sleeve between the top cover of the triaxial chamber and the loading rod to ensure that an air film is formed between the stainless steel loading rod and the top cover of the triaxial chamber during the air pressure loading process, thereby reducing the friction between the two and ensuring that the dynamic stress generated by the voice coil motor acts entirely on the specimen. Compared with the confining pressure of water pressure loading, it can effectively avoid the viscosity effect inside the triaxial chamber caused by high-frequency vibration that increases the friction of the loading rod. The voice coil motor is connected to the high-frequency data acquisition instrument through wires.

[0018] Compared with the prior art, the present invention has the following characteristics:

[0019] 1) The present invention can realize the coupling effect of static load and high-frequency cyclic load, and can realize 150Hz high-frequency low-amplitude cyclic load. The cycle time or number of times can be determined according to needs and the heating conditions of the voice coil motor; and realize accurate control of low stress amplitude as low as 0.5kPa, with an error of less than 0.1kPa.

[0020] 2) In the present invention, a low-friction vibration effect is achieved by designing a steel ball between the top cover of the triaxial chamber and the loading rod. Air pressure loading avoids the viscosity caused by the water pressure fluctuation in the triaxial chamber to increase the friction dissipation between the loading rod and the triaxial chamber. Air pressure loading can form an air film between the steel ball and the loading rod, thereby realizing the efficient transmission of the power of the voice coil motor to the sample, and achieving a high-frequency, low-amplitude stable vibration effect.

[0021] 3) The present invention can complete special triaxial tests that traditional dynamic triaxial instruments cannot complete, and has a simpler structure, is easier to manufacture, has lower costs, and has higher precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 It is a schematic diagram of the structure of the steel ball guide sleeve in the present invention;

[0024] Description of the markings in the figure:

[0025] 1—reaction frame, 2—high-frequency load sensor, 3—voice coil motor, 4—adapter rod, 5—loading rod, 6—top cover of triaxial chamber, 7—triaxial chamber, 8—specimen, 9—first high-pressure transparent tube, 10—acceleration sensor, 11—laser displacement sensor, 12—steel ball, 13—loading frame, 14—third high-pressure transparent tube, 15—second high-pressure transparent tube, 16—confining pressure sensor, 17—pore water pressure sensor, 18—air pressure source, 19—volumetric strain sensor, 20—high-frequency data acquisition instrument, 21—computer, 22—lifting platform, 23—specimen cap. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0027] Embodiment 1:

[0028] like Figure 1 A triaxial instrument for realizing the coupling of static load and high-frequency cyclic load shown in the figure includes a loading system and a measuring unit adapted to the loading system. The loading system includes a loading frame 13, a reaction frame 1 arranged on the loading frame 13, a lifting platform 22 arranged on the loading frame 13 and located below the reaction frame 1, a triaxial chamber 7 arranged on the lifting platform 22 and used to place a sample 8, a triaxial chamber top cover 6 arranged on the top of the triaxial chamber 7, a voice coil motor 3 arranged below the reaction frame 1, a loading rod 5 drivingly connected to the voice coil motor 3 and passing through the triaxial chamber top cover 6, and an air pressure source 18 connected to the interior of the triaxial chamber 7. The measuring unit includes a pressure measurement system, an axial force measurement system, an acceleration measurement system, a displacement measurement system, a volume measurement system, and an acquisition and analysis system.

[0029] The axial force measurement system includes a high-frequency load sensor 2 disposed between the reaction frame 1 and the voice coil motor 3 , and the acquisition and analysis system is electrically connected to the high-frequency load sensor 2 and the voice coil motor 3 , respectively.

[0030] The sample 8 is covered with a latex film, and a sample cap 23 is provided on the top, and the bottom of the loading rod 5 is in contact with the sample cap 23 .

[0031] like Figure 2 As shown, a steel ball guide sleeve is provided between the top cover 6 of the triaxial chamber and the loading rod 5 , and a plurality of steel balls 12 matched with the loading rod 5 are provided in the steel ball guide sleeve.

[0032] A first high-pressure transparent tube 9 is provided between the air pressure source 18 and the top of the sample 8, a second high-pressure transparent tube 15 is provided between the air pressure source 18 and the bottom of the sample 8, a third high-pressure transparent tube 14 is provided between the air pressure source 18 and the inner cavity of the triaxial chamber 7, and valves are provided on the first high-pressure transparent tube 9, the second high-pressure transparent tube 15, and the third high-pressure transparent tube 14.

[0033] The pressure measurement system includes a confining pressure sensor 16 arranged on the third high-pressure transparent tube 14 and a pore water pressure sensor 17 arranged on the second high-pressure transparent tube 15. The volume measurement system includes a body strain sensor 19 arranged on the first high-pressure transparent tube 9. The acquisition and analysis system is electrically connected to the confining pressure sensor 16, the pore water pressure sensor 17, and the body strain sensor 19, respectively.

[0034] The acceleration measurement system includes a transfer rod 4 arranged on the loading rod 5 and an acceleration sensor 10 arranged on the transfer rod 4 . The acquisition and analysis system is electrically connected to the acceleration sensor 10 .

[0035] The displacement measurement system includes a laser displacement sensor 11 disposed on the top cover 6 of the triaxial chamber, and the acquisition and analysis system is electrically connected to the laser displacement sensor 11 .

[0036] The acquisition and analysis system includes a high-frequency data acquisition instrument 20, which is electrically connected to the voice coil motor 3, the pressure measurement system, the axial force measurement system, the acceleration measurement system, the displacement measurement system, and the volume measurement system. The acquisition and analysis system also includes a computer 21 electrically connected to the high-frequency data acquisition instrument 20.

[0037] Embodiment 2:

[0038] A triaxial instrument that realizes the coupling of static load and high-frequency cyclic load. Compared with traditional instruments, its frequency range is 0-150Hz. The high-frequency and low-stress amplitude control of this embodiment is simpler than that of traditional instruments. The dynamic stress amplitude is generally lower than 6kPa, and high-efficiency dynamic load application and high-precision measurement can be achieved. The measured axial stress error is 0.1kPa, the water pressure error is 0.5kPa, the displacement error is 0.0003mm, and the volume monitoring error is 0.001ml.

[0039] The triaxial instrument comprises the following structures: a loading system, a pressure measurement system, an axial force measurement system, an acceleration measurement system, a displacement measurement system, and a volume measurement system.

[0040] The loading system includes a reaction frame 1, a voice coil motor 3, a loading rod 5, a three-axis chamber top cover 6, a three-axis chamber 7, a lifting platform 22, a loading frame 13, and an air pressure source 18; the high-frequency load sensor 2 is fixed to the reaction frame 1 by bolts, the voice coil motor 3 is fixed to the high-frequency load sensor 2 by bolts, the loading rod 5 is fixed to the bottom of the voice coil motor 3 by bolts, the bottom of the loading rod 5 is in contact with the sample cap 23, and a sample 8 is arranged in the three-axis chamber 7, and the sample 8 is covered with a latex film. The loading system can control static load and high-frequency cyclic load. The static load is achieved by adjusting the axial stress, confining pressure and back pressure. The static load is jointly controlled by the lifting platform 22, the triaxial chamber 7, the loading rod 5, the voice coil motor 3, the high-frequency load sensor 2, the reaction frame 1 and the friction between the loading rod 5 and the triaxial chamber top cover 6. The confining pressure and back pressure are provided by the air pressure source 18. The size of the confining pressure and back pressure is controlled by the pressure regulating valve on the second high-pressure transparent tube 15 and the third high-pressure transparent tube 14. The air pressure source 18 provides air pressure, adjusts the pressure regulating valve and applies it to the sample 8 through the triaxial chamber 7, thereby achieving a higher axial static stress level; the high-frequency cyclic load generates a high-frequency cyclic load by controlling the input current of the voice coil motor 3 through the computer 21, and the driving force acts on the sample 8 in the form of a dynamic load, thereby realizing the coupled loading of the static load and the high-frequency cyclic load.

[0041] The static load acts on the sample 8 through the confining pressure and the back pressure. The sample has a certain shear strength. The triaxial chamber 7 moves upward at a fixed rate, so that the sample 8 is subjected to triaxial compression and shear, thereby achieving the target strength; the dynamic load is generated by the low inertia Ampere force generated between the mobile permanent magnet and the fixed coil inside the voice coil motor 3. to achieve, the generated dynamic load has the characteristics of high frequency and low amplitude; a small marble 12 is laterally arranged inside the guide device inside the triaxial chamber top cover 6 to ensure that an air film is formed between the stainless steel loading rod 5 and the triaxial chamber top cover 6 during the air pressure loading process, thereby reducing the friction between the two and ensuring that the dynamic stress generated by the voice coil motor 3 is fully applied to the sample 8. Compared with the water pressure loading confining pressure, it can effectively avoid the viscosity effect generated inside the triaxial chamber 7 due to high-frequency vibration, which increases the friction of the loading rod 5; the voice coil motor 3 is connected to the high-frequency data acquisition instrument 20 through a wire.

[0042] The high-frequency load sensor 2 of the pressure measurement system is respectively fixed to the reaction frame 1 and the voice coil motor 3 by bolts. The air pressure source 18 is connected to the triaxial chamber 7 and the sample 8 through multiple high-pressure transparent tubes. A confining pressure sensor 16 is arranged between the third high-pressure transparent tube 14 and the air pressure source 18; a pore water pressure sensor 17 is arranged between the second high-pressure transparent tube 15 and the air pressure source 18. Under the condition of non-drainage test, closing the valve on the first high-pressure transparent tube 9 can realize high-precision measurement of pore water pressure. The confining pressure sensor 16 and the pore water pressure sensor 17 are connected to the high-frequency data acquisition instrument 20 through wires.

[0043] The high-frequency load sensor 2 of the axial force measurement system is connected to the loading frame 1 and the voice coil motor 3. The acquisition frequency can be adjusted as needed to realize the axial stress acquisition of the sample 8. The sensor circuit is connected to the high-frequency data acquisition instrument 20 through a wire.

[0044] The acceleration sensor 10 of the acceleration measurement system is fixed on the loading rod 5 through the adapter rod 4, and the sensor circuit is connected to the high-frequency data acquisition instrument 20 through a wire.

[0045] The laser displacement sensor 11 of the displacement measurement system is fixed on the top cover 6 of the triaxial chamber to measure the high-frequency displacement response of the sample 8 due to static shear and the vibration of the voice coil motor 3. The sensor circuit is connected to the high-frequency data acquisition instrument 20 through a wire.

[0046] The volumetric strain sensor 19 of the volume measurement system is connected between the air pressure source 18 and the top of the sample 8, and the volumetric strain is automatically and accurately measured through the volumetric strain sensor 19. The sensor circuit is connected to the high-frequency data acquisition instrument 20 through a wire.

[0047] In this embodiment, the pressure measurement system, axial force measurement system, acceleration measurement system, displacement measurement system and volume measurement system are connected to a high-frequency data acquisition instrument 20, whose single-channel maximum acquisition frequency can reach 5KHz. The high-frequency data acquisition instrument 20 is connected to a computer 21 for data display and storage.

[0048] During the experiment, different specifications of the triaxial chamber 7 and the size of the sample 8 (φ39.1mm, φ50mm, φ61.8mm) can be replaced according to the experimental requirements. The sample 8 is covered by a latex film, and the upper and lower ends of the latex film are respectively fixed on the bottom of the triaxial chamber 7 and the sample cap 23. The bottom end of the loading rod 5 is in contact with the sample cap 23, and the axial load is transmitted to the sample through the loading rod 5. The application of static load is achieved by controlling the axial stress, confining pressure and back pressure. The axial stress is achieved by controlling the lifting rate of the lifting platform 22 by the computer 21. The confining pressure is controlled by the air pressure source 18 and the pressure regulating valve on the second high-pressure transparent tube 15 and the third high-pressure transparent tube 14 to make the sample 8 reach the expected stress level; the back pressure is controlled by the air pressure source 18 and the pressure regulating valve on the third high-pressure transparent tube 14 to make the sample 8 reach the expected back pressure; the voice coil motor 3 in the loading system is controlled by the high-frequency data acquisition instrument 20 and the computer 21 to apply the high-frequency cyclic load to the sample 8. The pore water pressure in the sample 8 is measured by the pore water pressure sensor 17, the confining pressure is measured by the confining pressure sensor 16, the axial stress is measured by the high-frequency load sensor 2, the axial displacement is measured by the laser displacement sensor 11, the vibration acceleration is measured by the acceleration sensor 10, and the data is recorded by the high-frequency data acquisition instrument 20 and the computer 21.

[0049] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A triaxial apparatus that realizes the coupling of static load and high-frequency cyclic load, It is characterized in that The triaxial instrument comprises a loading system and a measuring unit adapted to the loading system, wherein the loading system comprises a loading frame (13), a reaction frame (1) arranged on the loading frame (13), a lifting platform (22) arranged on the loading frame (13) and located below the reaction frame (1), a triaxial chamber (7) arranged on the lifting platform (22) and used for placing a sample (8), a triaxial chamber top cover (6) arranged on the top of the triaxial chamber (7), a voice coil motor (3) arranged below the reaction frame (1), a loading rod (5) drivingly connected to the voice coil motor (3) and penetrating the triaxial chamber top cover (6), and an air pressure source (18) connected to the interior of the triaxial chamber (7); and the measuring unit comprises a pressure measurement system, an axial force measurement system, an acceleration measurement system, a displacement measurement system, a volume measurement system, and a collection and analysis system; The acceleration measurement system comprises a transfer rod (4) arranged on a loading rod (5) and an acceleration sensor (10) arranged on the transfer rod (4), and the acquisition and analysis system is electrically connected to the acceleration sensor (10); The axial force measurement system comprises a high-frequency load sensor (2) arranged between a reaction frame (1) and a voice coil motor (3), and the acquisition and analysis system is electrically connected to the high-frequency load sensor (2) and the voice coil motor (3) respectively; A steel ball guide sleeve is provided between the three-axis chamber top cover (6) and the loading rod (5), and a plurality of steel balls (12) matching the loading rod (5) are provided in the steel ball guide sleeve; A first high-pressure transparent tube (9) is provided between the air pressure source (18) and the top of the sample (8), a second high-pressure transparent tube (15) is provided between the air pressure source (18) and the bottom of the sample (8), a third high-pressure transparent tube (14) is provided between the air pressure source (18) and the inner cavity of the triaxial chamber (7), and valves are provided on the first high-pressure transparent tube (9), the second high-pressure transparent tube (15), and the third high-pressure transparent tube (14); The pressure measurement system comprises a confining pressure sensor (16) arranged on the third high-pressure transparent tube (14) and a pore water pressure sensor (17) arranged on the second high-pressure transparent tube (15); the volume measurement system comprises a body strain sensor (19) arranged on the first high-pressure transparent tube (9); and the acquisition and analysis system is electrically connected to the confining pressure sensor (16), the pore water pressure sensor (17), and the body strain sensor (19), respectively; The loading rod is responsible for transferring the load. The loading system is used to realize static loading and dynamic loading. It can realize high-frequency cyclic loading according to the static shear rate and axial stress conditions. The axial stress is controlled by controlling the height of the lifting platform on the loading frame. The confining pressure is provided by the triaxial chamber to realize the static stress level. The dynamic load is applied by the voice coil motor, which applies the dynamic load to the sample through the high-frequency movement of the internal mobile permanent magnet. The air pressure source connects the triaxial chamber and the sample through a high-pressure transparent tube. The confining pressure sensor and the pore water pressure sensor can realize high-precision measurement of the pore water pressure by closing the valve on the first high-pressure transparent tube under undrained test conditions. The volume strain sensor can realize high-precision monitoring of the volume change of the sample. The steel ball reduces the friction between the loading rod and the top cover of the triaxial chamber. At the same time, it can also form an air film by the flow of air during the high-frequency load vibration application process, which can reduce the energy dissipation of the voice coil motor vibration. Pneumatic loading avoids the viscosity caused by water pressure fluctuations in the triaxial chamber, which increases the friction dissipation between the loading rod and the triaxial chamber. Pneumatic loading forms an air film between the steel ball and the loading rod, thereby realizing the efficient transmission of the power of the voice coil motor to the sample, achieving high-frequency, low-amplitude and stable vibration.

2. A triaxial apparatus for realizing the coupling of static load and high-frequency cyclic load according to claim 1, It is characterized in that The sample (8) is covered with a latex film, and a sample cap (23) is provided on the top, and the bottom of the loading rod (5) is in contact with the sample cap (23).

3. A triaxial apparatus for realizing the coupling of static load and high-frequency cyclic load according to claim 1, It is characterized in that The displacement measurement system comprises a laser displacement sensor (11) arranged on a top cover (6) of a triaxial chamber, and the acquisition and analysis system is electrically connected to the laser displacement sensor (11).

4. A triaxial apparatus for realizing the coupling of static load and high-frequency cyclic load according to claim 1, It is characterized in that The acquisition and analysis system comprises a high-frequency data acquisition instrument (20), which is electrically connected to the voice coil motor (3), the pressure measurement system, the axial force measurement system, the acceleration measurement system, the displacement measurement system, and the volume measurement system.

5. A triaxial apparatus for realizing the coupling of static load and high-frequency cyclic load according to claim 4, It is characterized in that The data acquisition and analysis system further comprises a computer (21) electrically connected to the high-frequency data acquisition instrument (20).

Images