Rock high-frequency multi-surface direct shear test system and method considering fluid-solid coupling

Abstract

The invention relates to a rock high-frequency multi-surface direct shear test system and a rock high-frequency multi-surface direct shear test method considering fluid-solid coupling, and relates to the field of rock mechanics and seepage mechanics. Comprising a true triaxial loading frame which is used as a supporting frame of a test system and is used for clamping a sample and realizing a true triaxial stress state; the shear loading device is arranged in the true triaxial loading frame and is used for independently applying a horizontal shear load; the seepage module is connected with the true triaxial loading frame and is used for feeding fluid into the surface of the sample; the high-frequency dynamic disturbance device is arranged in the true triaxial loading frame and is used for applying a disturbance load; the data acquisition system is used for monitoring and recording stress, strain, displacement, acoustic emission signals and seepage parameters in the test process in real time; and the servo control system is used for coordinating and controlling static loading, shear loading, seepage and high-frequency dynamic disturbance processes. The invention provides a test system and method capable of comprehensively considering a fluid-structure interaction effect, high-frequency disturbance and multi-surface direct shear loading so as to overcome the defects in the prior art.

Description

Technical Field

[0001] The present invention relates to the fields of rock mechanics and seepage mechanics, and in particular to a high-frequency multi-surface direct shear test system and method for rocks taking fluid-solid coupling into consideration. Background Art

[0002] Rock mechanics testing is an important tool for studying the engineering stability of rock masses and the mechanisms of geological hazards, playing a particularly crucial role in deep underground engineering and fault activity analysis. As engineering geological conditions become increasingly complex, rocks often experience complex stress states in real environments, while also being subject to dynamic disturbance loads (such as blasting vibration, mechanical vibration, and seismic waves) and seepage. This places higher demands on the simulation capabilities of test equipment.

[0003] In existing technologies, high-frequency dynamic perturbation functions are often independent of the seepage and true triaxial shear loading systems, resulting in significant deviations between test conditions and actual operating conditions. Therefore, there is an urgent need to develop a test method that comprehensively considers fluid-structure interaction effects, high-frequency perturbation, and multi-faceted direct shear loading to address the shortcomings of existing technologies and provide a more reliable test basis for deep rock engineering safety assessments and geological disaster prevention and control. Summary of the Invention

[0004] The purpose of the present invention is to address the gaps in existing test equipment and test methods for high-frequency multi-faceted shear behavior of rocks under complex stress states, and to provide a high-frequency multi-faceted direct shear test system and method for rocks that takes fluid-solid coupling into consideration.

[0005] To achieve the above-mentioned object, the present invention provides a high-frequency multi-surface direct shear test system for rocks considering fluid-solid coupling, comprising: a true triaxial loading frame, a shear loading device, a seepage module, a high-frequency dynamic disturbance device, a data acquisition system, and a servo control system;

[0006] The true triaxial loading frame serves as the support frame of the test system and is used to clamp the specimen and achieve a true triaxial stress state;

[0007] The shear loading device is arranged in a true triaxial loading frame and is used to independently apply a horizontal shear load;

[0008] The seepage module is connected to the true triaxial loading frame to deliver the fluid to the sample surface;

[0009] The high-frequency dynamic disturbance device is arranged in a true triaxial loading frame and is used to apply a disturbance load;

[0010] The data acquisition system is respectively arranged in the true triaxial loading frame, the shear loading device and the seepage module, and is used to monitor and record the stress, strain, displacement, acoustic emission signal and seepage parameters during the test in real time;

[0011] The servo control system is connected to the true triaxial loading frame, the shear loading device, the seepage module and the high-frequency dynamic disturbance device, and is used to coordinate and control the static loading, shear loading, seepage and high-frequency dynamic disturbance processes.

[0012] Furthermore, the true triaxial loading frame includes a base, an outer support plate, a pressure chamber, a sample clamping device and loading head modules in six directions; the upper part of the base is fixedly connected to the outer support plate, and the pressure chamber is provided at the center position of the outer support plate; the sample clamping device is provided in the pressure chamber for fixing the standard cubic rock sample; the six loading head modules are respectively arranged in the front, back, left, right, up and down directions of the pressure chamber to achieve a true triaxial stress state; independent fluid channels are arranged inside the loading head modules, and the fluid channels are connected to the seepage module.

[0013] Furthermore, the outer support plate includes an upper outer plate, a lower outer plate, a right outer plate, a left outer plate, a front outer plate and a rear outer plate respectively connected to the six surfaces of the base;

[0014] The six loading head modules are respectively Y+ loading head module, Y- loading head module, X+ loading head module, X- loading head module, Z+ loading head module and Z- loading head module; the Y+ loading head module is fixed on the upper outer panel, the Y- loading head module is fixed on the lower outer panel, the X+ loading head module is fixed on the right outer panel, the X- loading head module is fixed on the left outer panel, the Z+ loading head module is fixed on the front outer panel, and the Z- loading head module is fixed on the rear outer panel.

[0015] Furthermore, the shear loading device is integrated into the X+ loading head module and the X- loading head module, and is respectively connected to the X+ loading head module and the X- loading head module through a slideway, for independently applying a horizontal shear load.

[0016] Furthermore, the shear loading device includes an X+ shear head and an X- shear head, the X+ shear head is connected to the X+ loading head module through a slide, and the X- shear head is connected to the X- loading head module through a slide, forming a precise fit with the sample; an external gap of the X+ shear head is reserved between the X+ shear head and the X+ loading head module, and an external gap of the X- shear head is reserved between the X- shear head and the X- loading head module to ensure independent sliding.

[0017] Furthermore, the seepage module includes a constant flow and constant pressure pump, a fluid storage device, a sealing pressure booster pump and a rubber sealing ring; the fluid storage device is connected to the constant flow and constant pressure pump, and the constant flow and constant pressure pump is connected to the sample contact surface through the fluid channel in the loading pressure head module; the rubber sealing ring is arranged between the inner wall of the sample clamping device and the sample, and cooperates with the sealing pressure booster pump to achieve seepage boundary sealing.

[0018] Furthermore, the high-frequency dynamic disturbance device includes a dynamic loading module No. 1 and a dynamic loading module No. 2, the dynamic loading module No. 1 is integrated in the X+ loading head module, and the dynamic loading module No. 2 is integrated in the X- loading head module; the dynamic loading module No. 1 and the dynamic loading module No. 2 have the same structure, including a servo valve, an accumulator, an oil cylinder and a piston rod, the accumulator is connected to the oil cylinder through a pipeline, a servo valve is provided on the pipeline, the piston rod is retractably arranged in the oil cylinder, and the servo control system is electrically connected to the servo valve; the dynamic loading module No. 1 and the dynamic loading module No. 2 are used to apply sinusoidal waves, trapezoidal waves, triangular waves, sawtooth waves and seismic wave disturbance loads with a frequency of 0.1 to 50 Hz and an amplitude of up to 400 kN.

[0019] Furthermore, the data acquisition system includes a force and displacement sensor, an acoustic emission acquisition device, a fluid pressure sensor and a flow meter. The six loading head modules are equipped with a force and displacement sensor and an acoustic emission acquisition device. The fluid pressure sensor and flow meter are arranged in the fluid channel; they are used to monitor and record the stress, strain, displacement, acoustic emission signal and seepage parameters in real time during the test.

[0020] A high-frequency multi-surface direct shear test method for rock considering fluid-solid coupling is implemented using any of the above-mentioned high-frequency multi-surface direct shear test systems for rock considering fluid-solid coupling, comprising the following steps:

[0021] S1. Sample preparation stage: including: internal rock column: a rectangular rock column with dimensions of 50mm×50mm×100mm; external sample: a hollow cube with external dimensions of 100mm×100mm×100mm and internal dimensions of 50mm×50mm×100mm; each side length of the external sample is 6mm longer than the side length of the indenter, and the 6mm length is reserved for the indenter to prevent collision of the indenters in different directions during loading; the sample is then chamfered to reduce stress concentration during loading, with 12 edges chamfered at an angle of 45° and a chamfer depth of 3mm; the internal rock column is then precisely embedded in the hollow part of the external sample to ensure that the contact surface is completely consistent; sealant is applied to the surface of the external sample and a rubber sealing ring is installed;

[0022] S2. Specimen installation phase: First, use the loading and unloading device to install the specimen into the specimen clamping device, making sure that the internal rock column is perpendicular to the X+ loading head module and the X- loading head module. Then, install the Y- loading head module at the bottom of the loading frame. Then, install the specimen clamping device with the specimen onto the Y- loading head module. Then, install the loading head modules in the remaining five directions. When installing the X+ loading head module and the X- loading head module with the shear loading device, check that the shear loading device is aligned with the end face of the internal rock column. When installing the loading head modules in the six directions, connect the fluid pipelines and check for sealing.

[0023] S3, Equipment inspection stage: Turn on the hydraulic source, computer and oscilloscope, observe the operating status of all force and displacement sensors, and proceed to the next step if there is no abnormality;

[0024] S4, preload application stage: Servo control six loading head modules in the X, Y, and Z directions to symmetrically and slowly apply force to 10kN. After stabilization, the sealing pressure is loaded to 5kN. After the loading is completed and stabilized for one minute, the next step is carried out;

[0025] S5, static loading stage: using force control mode to load to the first preset stress state;

[0026] S6, seepage-shear-disturbance stage: Fluid is injected through a constant flow and constant pressure pump, and the shear loading device and high-frequency dynamic disturbance device are started simultaneously. Shear force and high-frequency disturbance load are applied under the preset stress state until the acoustic emission system detects sample failure. Shear stress-strain data and seepage parameters are recorded;

[0027] S7, damage monitoring stage: when the acoustic emission signal suddenly changes or the permeability increases suddenly, the sample is judged to be damaged and the loading is terminated;

[0028] S8, unloading stage: gradually reduce the shear stress and seepage pressure, and simultaneously unload the triaxial stress to zero;

[0029] S9. End of test: Take out the sample, observe the sample shape and fracture state, and complete the test;

[0030] S10. Clean the debris from the loading head module and the sample in the pressure chamber, and turn off the water and electricity.

[0031] The beneficial effects of the present invention are:

[0032] Compared with existing direct shear testing machines, the present invention offers the advantage of enabling simultaneous multi-directional shear and seepage testing under true triaxial stress conditions and high-frequency dynamic disturbances. Through independently controlled loading head modules in six directions and dedicated shear and high-frequency dynamic disturbance devices integrated in the X± directions, it can precisely apply true triaxial stress states (σ1≠σ2≠σ3) and high-frequency dynamic disturbances, achieving bidirectional shear loading. Simultaneously, a fluid injection and measurement system enables seepage testing. This provides more comprehensive and realistic testing conditions for studying the mechanical behavior and failure mechanisms of rock under complex stresses, seepage coupling, and high-frequency disturbances, and possesses significant engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the local structure of the present invention Figure 1 ;

[0034] Figure 2 This is a schematic diagram of the local structure of the present invention Figure 2 ;

[0035] Figure 3 Schematic diagram of the loading head module in the Y and Z directions of the present invention;

[0036] Figure 4 Schematic diagram of the loading head module in the X direction of the present invention;

[0037] Figure 5 It is a front view of the rock sample of the present invention;

[0038] Figure 6 It is a schematic diagram of the overall structure of the present invention.

[0039] Among them, in the figure:

[0040] 1. True triaxial loading frame, 2. Metal frame, 3. Loading frame, 4-1. Upper outer plate, 4-2. Lower outer plate, 4-3. Right outer plate, 4-4. Left outer plate, 4-5. Front outer plate, 4-6. Rear outer plate, 5-1. X+ shear head, 5-2. X- shear head, 5-3. X+ shear head external gap, 5-4. X- shear head external gap, 6-1. Y+ loading head module, 6-2. Y- loading head module, 6-3. X+ loading head module, 6-4. X- loading head module, 6-5. Z+ loading Pressure head module, 6-6. Z-loading pressure head module, 7-1. Acoustic emission acquisition device, 7-2. Force and displacement sensor, 8-1. External sample, 8-2. Internal rock column, 9. Rubber sealing ring, 10-1. Y+ fluid channel, 10-2. Y- fluid channel, 10-3. X+ fluid channel, 10-4. X- fluid channel, 10-5. Z+ fluid channel, 10-6. Z- fluid channel, 11. Seepage module, 12. Constant flow and constant pressure pump, 13. Fluid storage device, 14. Servo control system, 15. Cylinder, 16. Piston rod. DETAILED DESCRIPTION

[0041] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] In this application, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe this application and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0044] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0045] Furthermore, the terms "installed," "disposed," "provided with," "connected," "connected," and "socketed" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0046] Example 1

[0047] like Figure 1-6 As shown, the present invention provides a high-frequency multi-surface direct shear test system for rocks considering fluid-solid coupling, comprising: a true triaxial loading frame 1, a shear loading device, a seepage module 11, a high-frequency dynamic disturbance device, a data acquisition system, and a servo control system 14;

[0048] The true triaxial loading frame 1 serves as a support frame for the test system and is used to clamp the specimen and achieve a true triaxial stress state;

[0049] The shear loading device is arranged in the true triaxial loading frame 1 and is used to independently apply horizontal shear load;

[0050] The seepage module 11 is connected to the true triaxial loading frame 1 to deliver the fluid to the sample surface;

[0051] The high-frequency dynamic disturbance device is arranged in the true triaxial loading frame 1 and is used to apply a disturbance load;

[0052] The data acquisition system is respectively arranged in the true triaxial loading frame 1, the shear loading device and the seepage module 11, and is used to monitor and record the stress, strain, displacement, acoustic emission signal and seepage parameters during the test in real time;

[0053] The servo control system 14 is connected to the true triaxial loading frame 1, the shear loading device, the seepage module 11 and the high-frequency dynamic disturbance device, and is used to coordinate and control the static loading, shear loading, seepage and high-frequency dynamic disturbance processes. The loading rate is adjustable from 0.001 to 1 mm / min, the control accuracy is better than 0.1% FS, and it has an automatic overload protection function.

[0054] The true triaxial loading frame 1 comprises a base, an outer support plate, a pressure chamber, a sample clamping device, and six loading head modules. The upper portion of the base is fixedly connected to the outer support plate, and the pressure chamber is located at the center of the outer support plate. The sample clamping device is located within the pressure chamber to secure a standard cubic rock sample. The six loading head modules are arranged in the front, back, left, right, and top and bottom directions of the pressure chamber to achieve a true triaxial stress state. Independent fluid channels are arranged within each loading head module, and these fluid channels are connected to the seepage module 11. In this embodiment, the sample clamping device uses a metal frame 2.

[0055] The outer support plate includes an upper outer plate 4-1, a lower outer plate 4-2, a right outer plate 4-3, a left outer plate 4-4, a front outer plate 4-5 and a rear outer plate 4-6 respectively connected to the six surfaces of the base; the six loading pressure head modules are Y+ loading pressure head module 6-1, Y- loading pressure head module 6-2, X+ loading pressure head module 6-3, X- loading pressure head module 6-4, Z+ loading pressure head module 6-5 and Z- loading pressure head module 6 -6; the Y+ loading head module 6-1 is fixed on the upper outer plate 4-1, the Y- loading head module 6-2 is fixed on the lower outer plate 4-2, the X+ loading head module 6-3 is fixed on the right outer plate 4-3, the X- loading head module 6-4 is fixed on the left outer plate 4-4, the Z+ loading head module 6-5 is fixed on the front outer plate 4-5, and the Z- loading head module 6-6 is fixed on the rear outer plate 4-6. When conducting the experiment, the top of the Y+ loading head module 6-1 is connected to the Y+ static loading module; the Y+ fluid channel 10-1 is arranged inside the Y+ loading head module 6-1; the Y+ fluid channel 10-1 is connected to the output end of the seepage module 11; the top of the Y- loading head module 6-2 is connected to the Y- static loading module; the Y- loading head module 6-2 is arranged inside the Y- fluid channel 10-2; the Y- fluid channel 10-2 is connected to the input end of the seepage module 11; the top of the X+ loading head module 6-3 is connected to the X+ static loading module, and the X+ fluid channel 10-3 is arranged inside the X+ loading head module 6-3; the X+ fluid channel 10-3 is connected to the output end of the seepage module 11 end is connected; the top of the X-loading head module 6-4 is connected to the X-static loading module, the X-loading head module 6-4 is internally provided with an X-fluid channel 10-4, and the X-fluid channel 10-4 is connected to the input end of the seepage module 11; the top of the Z-loading head module 6-6 is connected to the Z-static loading module, the Z-loading head module 6-6 is internally provided with a Z-fluid channel 10-6, and the Z-fluid channel 10-6 is connected to the output end of the seepage module 11; the top of the Z+loading head module 6-5 is connected to the Z+static loading module, the Z+loading head module 6-5 is internally provided with a Z+fluid channel 10-5, and the Z+fluid channel 10-5 is connected to the input end of the seepage module 11.

[0056] The shear loading device is integrated into the X+ loading head module 6-3 and the X- loading head module 6-4, and is connected to the X+ loading head module 6-3 and the X- loading head module 6-4 respectively through a slideway, for independently applying a horizontal shear load. The shear loading device includes an X+ shear head 5-1 and an X- shear head. The X+ shear head 5-1 is connected to the X+ loading head module 6-3 through a slideway, and the X- shear head is connected to the X- loading head module 6-4 through a slideway. The head size is 49mm×49mm, forming a precise fit with the sample to ensure accurate force transmission during shear loading and no damage to the head due to squeezing of the external sample 8-1; an external gap 5-3 of the X+ shear head is reserved between the X+ shear head 5-1 and the X+ loading head module 6-3, and an external gap of the X- shear head is reserved between the X- shear head and the X- loading head module 6-4 to ensure independent sliding.

[0057] The seepage module 11 includes a constant flow and constant pressure pump 12, a fluid storage device 13, a sealing pressure booster pump and a rubber sealing ring 9; the fluid storage device 13 is connected to the constant flow and constant pressure pump 12, and the constant flow and constant pressure pump 12 is connected to the sample contact surface through the fluid channel in the loading pressure head module; the rubber sealing ring 9 is arranged between the inner wall of the sample clamping device and the sample, and cooperates with the sealing pressure booster pump to achieve seepage boundary sealing.

[0058] The high-frequency dynamic disturbance device includes a dynamic loading module No. 1 and a dynamic loading module No. 2. The dynamic loading module No. 1 is integrated into the X+ loading head module 6-3, and the dynamic loading module No. 2 is integrated into the X- loading head module 6-4; the dynamic loading module No. 1 and the dynamic loading module No. 2 have the same structure, including a servo valve, an accumulator, a cylinder 15 and a piston rod 16. The accumulator is connected to the cylinder 15 through a pipeline, and a servo valve is provided on the pipeline. The piston rod 16 is retractably arranged in the cylinder 15, and the servo control system 14 is electrically connected to the servo valve; the dynamic loading module No. 1 and the dynamic loading module No. 2 are used to apply sinusoidal waves, trapezoidal waves, triangular waves, sawtooth waves and seismic wave disturbance loads with a frequency of 0.1 to 50 Hz and an amplitude of up to 400 kN.

[0059] The data acquisition system includes a force and displacement sensor 7-2, an acoustic emission acquisition device 7-1, a fluid pressure sensor and a flow meter. The six loading head modules are each equipped with a force and displacement sensor 7-2 and an acoustic emission acquisition device 7-1. The fluid pressure sensor and flow meter are arranged in the fluid channel. They are used to monitor and record the stress, strain, displacement, acoustic emission signal and seepage parameters in real time during the test.

[0060] Example 2

[0061] The present invention also provides a high-frequency multi-surface direct shear test method for rock considering fluid-solid coupling, which is implemented using any of the above-mentioned high-frequency multi-surface direct shear test systems for rock considering fluid-solid coupling, and includes the following steps:

[0062] S1. Sample preparation stage: including: internal rock column 8-2: a rectangular rock column with dimensions of 50mm×50mm×100mm; external sample 8-1: a hollow cube with external dimensions of 100mm×100mm×100mm and internal dimensions of 50mm×50mm×100mm; each side length of the external sample 8-1 is 6mm longer than the side length of the indenter, and the 6mm length is the reserved distance for the indenter to prevent collision of the indenters in different directions during loading; the sample is then chamfered to reduce stress concentration during loading, with all 12 edges chamfered at an angle of 45° and a chamfer depth of 3mm; the internal rock column 8-2 is then precisely embedded in the hollow part of the external sample 8-1, ensuring that the contact surfaces are completely aligned; sealant is applied to the surface of the external sample 8-1 and a rubber sealing ring 9 is installed;

[0063] S2. Sample installation stage: First, use the loading and unloading device to install the sample into the sample clamping device, making sure that the internal rock column 8-2 is perpendicular to the X+ loading head module 6-3 and the X- loading head module 6-4. Then, install the Y- loading head module 6-2 at the bottom of the loading frame 3. Then, install the sample clamping device containing the sample onto the Y- loading head module 6-2. Then, install the loading head modules in the remaining five directions. When installing the X+ loading head module 6-3 and the X- loading head module 6-4 with the shear loading device, check that the shear loading device is aligned with the end surface of the internal rock column 8-2. When installing the loading head modules in the six directions, connect the fluid pipelines and check for sealing.

[0064] S3, Equipment inspection stage: Turn on the hydraulic source, computer and oscilloscope, observe the operating status of all force and displacement sensors 7-2, and proceed to the next step if there is no abnormality;

[0065] S4, preload application stage: Servo control six loading head modules in the X, Y, and Z directions to symmetrically and slowly apply force to 10kN. After stabilization, the sealing pressure is loaded to 5kN. After the loading is completed and stabilized for one minute, the next step is carried out;

[0066] S5, static loading stage: using force control mode to load to the first preset stress state;

[0067] S6, seepage-shear-disturbance stage: Fluid is injected through the constant flow and constant pressure pump 12, and the shear loading device and the high-frequency dynamic disturbance device are started simultaneously. Shear force and high-frequency disturbance load are applied under the preset stress state until the acoustic emission system detects sample failure, and shear stress-strain data and seepage parameters are recorded;

[0068] S7, damage monitoring stage: when the acoustic emission signal suddenly changes or the permeability increases suddenly, the sample is judged to be damaged and the loading is terminated;

[0069] S8, unloading stage: gradually reduce the shear stress and seepage pressure, and unload the triaxial stress to zero simultaneously to avoid the deviation stress caused by unloading too quickly or unloading in the three directions asynchronously, which will damage the specimen;

[0070] S9. End of test: Take out the sample, observe the sample shape and fracture state, and complete the test;

[0071] S10. Clean the debris from the loading head module and the sample in the pressure chamber, and turn off the water and electricity.

[0072] This invention is used to study the shear failure mechanism and permeability evolution of rock under the coupled effects of complex stress, seepage, and high-frequency dynamic perturbation. In existing technologies, the high-frequency dynamic perturbation function is often independent of the seepage and true triaxial shear loading systems, resulting in significant deviations between the test conditions and actual operating conditions. This invention proposes a high-frequency, multi-faceted direct shear test system and method for rock that takes fluid-solid coupling into account. The system integrates a loading head module with six independently controlled directions, combined with a bidirectional shear loading device, a seepage module, and a high-frequency dynamic perturbation device. This system can accurately apply a true triaxial stress state where σ1≠σ2≠σ3 and simultaneously achieve high-frequency dynamic perturbation (0.1-50Hz, maximum amplitude 400kN) coupled with seepage loading. The system is connected to a constant-flow and constant-pressure pump via a fluid channel, and is equipped with a sealing pressure booster pump and a rubber seal to ensure the sealing of the seepage boundary. The dynamic perturbation module supports various waveform loading methods, including sinusoidal, trapezoidal, and seismic waves. The test method includes nested specimen preparation, multi-directional synchronous loading, seepage-shear-perturbation coupled loading, and dynamic failure monitoring. Compared with the existing technology, the present invention realizes the multi-field coupling simulation of true triaxial stress, seepage and high-frequency dynamic disturbance for the first time, providing more realistic experimental data for deep rock engineering safety assessment and geological disaster prevention and control, and has significant engineering application value.

[0073] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-frequency multi-surface direct shear test system for rocks considering fluid-solid coupling, characterized by: include: True triaxial loading frame, shear loading device, seepage module, high-frequency dynamic perturbation device, data acquisition system and servo control system; The true triaxial loading frame serves as the support frame of the test system and is used to clamp the specimen and achieve a true triaxial stress state; The shear loading device is arranged in a true triaxial loading frame and is used to independently apply a horizontal shear load; The seepage module is connected to the true triaxial loading frame to deliver the fluid to the sample surface; The high-frequency dynamic disturbance device is arranged in a true triaxial loading frame and is used to apply a disturbance load; The data acquisition system is respectively arranged in the true triaxial loading frame, the shear loading device and the seepage module, and is used to monitor and record the stress, strain, displacement, acoustic emission signal and seepage parameters during the test in real time; The servo control system is connected to the true triaxial loading frame, the shear loading device, the seepage module and the high-frequency dynamic disturbance device, and is used to coordinate and control the static loading, shear loading, seepage and high-frequency dynamic disturbance processes.

2. A high-frequency multi-surface direct shear test system for rock considering fluid-solid coupling as described in claim 1, characterized in that: The true triaxial loading frame includes a base, an outer support plate, a pressure chamber, a sample clamping device and loading head modules in six directions; the upper part of the base is fixedly connected to the outer support plate, and the pressure chamber is provided at the center of the outer support plate; the sample clamping device is provided in the pressure chamber for fixing a standard cubic rock sample; the six loading head modules are respectively arranged in the front, back, left, right, top and bottom directions of the pressure chamber to achieve a true triaxial stress state; independent fluid channels are arranged inside the loading head modules, and the fluid channels are connected to the seepage module.

3. A high-frequency multi-surface direct shear test system for rock considering fluid-solid coupling according to claim 2, characterized in that: The outer support plate includes an upper outer plate, a lower outer plate, a right outer plate, a left outer plate, a front outer plate and a rear outer plate respectively connected to the six surfaces of the base; The six loading head modules are respectively Y+ loading head module, Y- loading head module, X+ loading head module, X- loading head module, Z+ loading head module and Z- loading head module; the Y+ loading head module is fixed on the upper outer panel, the Y- loading head module is fixed on the lower outer panel, the X+ loading head module is fixed on the right outer panel, the X- loading head module is fixed on the left outer panel, the Z+ loading head module is fixed on the front outer panel, and the Z- loading head module is fixed on the rear outer panel.

4. A high-frequency multi-surface direct shear test system for rock considering fluid-solid coupling according to claim 3, characterized in that: The shear loading device is integrated into the X+ loading head module and the X- loading head module, and is respectively connected to the X+ loading head module and the X- loading head module through a slideway, and is used to independently apply horizontal shear loads.

5. A high-frequency multi-surface direct shear test system for rock considering fluid-solid coupling according to claim 4, characterized in that: The shear loading device includes an X+ shear head and an X- shear head. The X+ shear head is connected to the X+ loading head module through a slide, and the X- shear head is connected to the X- loading head module through a slide, forming a precise fit with the sample; an external gap of the X+ shear head is reserved between the X+ shear head and the X+ loading head module, and an external gap of the X- shear head is reserved between the X- shear head and the X- loading head module to ensure independent sliding.

6. A high-frequency multi-surface direct shear test system for rock considering fluid-solid coupling according to claim 2 or 5, characterized in that: The seepage module includes a constant flow and constant pressure pump, a fluid storage device, a sealing pressure booster pump and a rubber sealing ring; the fluid storage device is connected to the constant flow and constant pressure pump, and the constant flow and constant pressure pump is connected to the sample contact surface through the fluid channel in the loading pressure head module; the rubber sealing ring is arranged between the inner wall of the sample clamping device and the sample, and cooperates with the sealing pressure booster pump to achieve seepage boundary sealing.

7. The high-frequency multi-surface direct shear test system for rock considering fluid-solid coupling according to claim 3, characterized in that: The high-frequency dynamic disturbance device includes a dynamic loading module No. 1 and a dynamic loading module No.

2. The dynamic loading module No. 1 is integrated into the X+ loading head module, and the dynamic loading module No. 2 is integrated into the X- loading head module. The dynamic loading module No. 1 and the dynamic loading module No. 2 have the same structure and include a servo valve, an accumulator, an oil cylinder and a piston rod. The accumulator is connected to the oil cylinder through a pipeline. A servo valve is provided on the pipeline. The piston rod is retractably arranged in the oil cylinder. The servo control system is electrically connected to the servo valve. The dynamic loading module No. 1 and the dynamic loading module No. 2 are used to apply sinusoidal waves, trapezoidal waves, triangular waves, sawtooth waves and seismic wave disturbance loads with a frequency of 0.1 to 50 Hz and an amplitude of up to 400 kN.

8. The high-frequency multi-surface direct shear test system for rock considering fluid-solid coupling according to claim 6, characterized in that: The data acquisition system includes a force and displacement sensor, an acoustic emission acquisition device, a fluid pressure sensor and a flow meter. The six loading head modules are each equipped with a force and displacement sensor and an acoustic emission acquisition device. The fluid pressure sensor and flow meter are arranged in the fluid channel and are used to monitor and record stress, strain, displacement, acoustic emission signals and seepage parameters in real time during the test.

9. A high-frequency multi-surface direct shear test method for rock considering fluid-solid coupling, characterized in that: The rock high-frequency multi-surface direct shear test system considering fluid-solid coupling according to any one of claims 1 to 8 is used for implementation, comprising the following steps: S1. Sample preparation stage: including: internal rock column: a rectangular rock column with dimensions of 50mm×50mm×100mm; external sample: a hollow cube with external dimensions of 100mm×100mm×100mm and internal dimensions of 50mm×50mm×100mm; each side length of the external sample is 6mm longer than the side length of the indenter, and the 6mm length is reserved for the indenter to prevent collision of the indenters in different directions during loading; the sample is then chamfered to reduce stress concentration during loading, with 12 edges chamfered at an angle of 45° and a chamfer depth of 3mm; the internal rock column is then precisely embedded in the hollow part of the external sample to ensure that the contact surface is completely consistent; sealant is applied to the surface of the external sample and a rubber sealing ring is installed; S2. Specimen installation phase: First, use the loading and unloading device to install the specimen into the specimen clamping device, making sure that the internal rock column is perpendicular to the X+ loading head module and the X- loading head module. Then, install the Y- loading head module at the bottom of the loading frame. Then, install the specimen clamping device with the specimen onto the Y- loading head module. Then, install the loading head modules in the remaining five directions. When installing the X+ loading head module and the X- loading head module with the shear loading device, check that the shear loading device is aligned with the end face of the internal rock column. When installing the loading head modules in the six directions, connect the fluid pipelines and check for sealing. S3, Equipment inspection stage: Turn on the hydraulic source, computer and oscilloscope, observe the operating status of all force and displacement sensors, and proceed to the next step if there is no abnormality; S4, preload application stage: Servo control six loading head modules in the X, Y, and Z directions to symmetrically and slowly apply force to 10kN. After stabilization, the sealing pressure is loaded to 5kN. After the loading is completed and stabilized for one minute, the next step is carried out; S5, static loading stage: using force control mode to load to the first preset stress state; S6, seepage-shear-disturbance stage: Fluid is injected through a constant flow and constant pressure pump, and the shear loading device and high-frequency dynamic disturbance device are started simultaneously. Shear force and high-frequency disturbance load are applied under the preset stress state until the acoustic emission system detects sample failure. Shear stress-strain data and seepage parameters are recorded; S7, damage monitoring stage: when the acoustic emission signal suddenly changes or the permeability increases suddenly, the sample is judged to be damaged and the loading is terminated; S8, unloading stage: gradually reduce the shear stress and seepage pressure, and simultaneously unload the triaxial stress to zero; S9. End of test: Take out the sample, observe the sample shape and fracture state, and complete the test; S10. Clean the debris from the loading head module and the sample in the pressure chamber, and turn off the water and electricity.

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