A deep engineering dynamic disturbance hard rock true triaxial CT real-time scanning experimental device

Abstract

A kind of deep engineering dynamic disturbance hard rock true triaxial CT real-time scanning experimental device belongs to rock mechanics experimental technical field, including base, true triaxial loading mechanism and CT real-time scanning mechanism.The present application can realize the whole process CT real-time scanning of dynamic disturbance true triaxial experiment, can obtain the internal crack development process information of rock at different loading time, overcome the problem that rock failure cannot be directly observed in traditional true triaxial experiment and other monitoring means error is big, result is not accurate;Stress release and dynamic disturbance coupling true triaxial experiment can be carried out, the working condition of deep engineering hydraulic fracturing technology to prevent dynamic disaster is simulated, the internal crack evolution process of rock at different time is obtained by CT real-time scanning, so that the internal crack evolution process of rock is realized accurate three-dimensional reconstruction;Dynamic disturbance true triaxial experiment in three directions, long fatigue true triaxial experiment, hydraulic fracturing dynamic disturbance coupling true triaxial experiment can be carried out, CT real-time scanning and three-dimensional reconstruction are realized in the process of experiment.

Description

Technical Field

[0001] This invention belongs to the field of rock mechanics experimental technology, and in particular relates to a real-time triaxial CT scanning experimental device for deep engineering dynamic disturbance hard rock. Background Technology

[0002] In the fields of rock mechanics and deep engineering, studying the development process of rock cracks under complex working conditions such as high stress unloading, dynamic disturbance and hydraulic fracturing stress release is of great significance for revealing the failure mechanism of rocks and ensuring the safety of deep tunnel construction, mine disaster prevention and control, and unconventional resource development.

[0003] True triaxial experimental setups, as crucial equipment for simulating triaxial principal stress states underground, play an irreplaceable role in fundamental rock mechanics research. However, existing true triaxial experimental systems still have certain limitations in terms of functional integration, observation accuracy, and ease of operation. Due to limitations in loading methods, they are unable to meet the needs of simulating complex geological environments and monitoring refined crack evolution.

[0004] Traditional true triaxial experimental setups are mostly statically loaded and are mainly used to conduct conventional triaxial compression tests to simulate excavation stress paths. However, for the multi-source dynamic disturbances (earthquakes, TBM excavation, rock bursts, blasting) that are common in deep engineering, existing true triaxial experimental setups either lack dynamic loading modules or can only achieve unidirectional or low-frequency disturbances, and cannot accurately simulate multi-level disturbance processes under different amplitudes, frequencies and loading paths.

[0005] Meanwhile, as an important technical means for stress release and dynamic disaster prevention in tunnels and mines, hydraulic fracturing technology is often unable to achieve hydraulic fracturing function in most existing true triaxial experimental devices, let alone work in conjunction with dynamic disturbance loading. This results in a significant lack of research on rock fracture behavior under the coupling of static-dynamic-flow multi-field effects.

[0006] Currently, in existing true triaxial experiments with dynamic disturbances, the monitoring of hard rock fractures mainly relies on acoustic emission (AE), resistivity, elastic wave velocity, and deformation measurements. However, these fracture monitoring methods generally suffer from low spatial resolution, susceptibility to noise interference, and difficulty in accurately characterizing the crack development process and propagation path, making it difficult to meet the requirements for real-time and accurate monitoring of the entire process of microcrack initiation, propagation, and penetration. Taking acoustic emission monitoring as an example, the interference signals generated by dynamic disturbances in the experiment are difficult to separate, the positioning accuracy is insufficient, and it is difficult to accurately describe the crack propagation process inside the rock under the action of dynamic disturbances.

[0007] Industrial CT technology, as a non-destructive imaging method, has been applied in conventional uniaxial compression and partial static loading experiments of rocks. However, due to limitations in the existing pressure chamber structure and loading system, CT scans cannot perform continuous imaging throughout the entire true triaxial loading process, which severely restricts experimental accuracy and data integrity. Summary of the Invention

[0008] To address the problems of existing technologies, this invention provides a real-time triaxial CT scanning experimental device for deep engineering dynamic disturbance hard rock. This device enables real-time CT scanning of the entire process of a true triaxial dynamic disturbance experiment, acquiring information on the development process of internal rock cracks at different loading times. It overcomes the difficulties of traditional true triaxial experiments, such as the inability to directly observe rock fracture and the large errors and inaccurate results of other monitoring methods. It can conduct true triaxial experiments involving the coupling effect of stress release and dynamic disturbance, simulating the working conditions of deep engineering hydraulic fracturing technology for preventing dynamic disasters. Through real-time CT scanning, it acquires the evolution process of internal rock cracks at different times, enabling precise three-dimensional reconstruction of the internal rock crack evolution process. Furthermore, it can conduct rock mechanics experiments such as three-directional dynamic disturbance true triaxial experiments, long-term fatigue true triaxial experiments, and hydraulic fracturing dynamic disturbance coupled true triaxial experiments, achieving real-time CT scanning and three-dimensional reconstruction during the experiments.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a real-time triaxial CT scanning experimental device for deep engineering dynamic disturbance hard rock, comprising a base, a true triaxial loading mechanism, and a real-time CT scanning mechanism; the base is horizontally fixed on the ground; the true triaxial loading mechanism is fixedly disposed in the middle of the base; the real-time CT scanning mechanism includes a radiation emitting unit and a radiation receiving unit, the true triaxial loading mechanism being located between the radiation emitting unit and the radiation receiving unit; a horizontal sliding attitude adjustment mechanism is provided on the upper surface of the base, and both the radiation emitting unit and the radiation receiving unit are disposed on the horizontal sliding attitude adjustment mechanism.

[0010] The true triaxial loading mechanism includes a support, a frame, an upper dynamic disturbance loading component, an upper servo-electric turntable, a lower dynamic disturbance loading component, a lower servo-electric turntable, and a three-rigid sample fixture. The support is fixedly installed on the upper surface of the base. The frame adopts a U-shaped structure and is vertically fixedly installed above the support. The upper servo-electric turntable is horizontally positioned in the middle of the top beam of the frame. The upper dynamic disturbance loading component is positioned on the upper servo-electric turntable. The lower servo-electric turntable is horizontally positioned in the middle of the bottom beam of the frame. The lower dynamic disturbance loading component is positioned on the lower servo-electric turntable. The three-rigid sample fixture is located between the upper and lower dynamic disturbance loading components.

[0011] The upper dynamic disturbance loading assembly includes a first servo hydraulic actuator, a first linear servo electric cylinder, a second linear servo electric cylinder, a third linear servo electric cylinder, a fourth linear servo electric cylinder, an upper rigid support cylinder, and an upper rigid support plate. The upper rigid support cylinder is coaxially and vertically fixed on the upper servo electric turntable. The first servo hydraulic actuator is coaxially fixed on the inner side of the upper rigid support cylinder. The upper rigid support plate is fixedly installed at the bottom opening of the upper rigid support cylinder. The first, second, third, and fourth linear servo electric cylinders are all horizontally fixed on the edge of the upper rigid support plate and are evenly distributed in sequence along the circumferential direction.

[0012] The lower dynamic disturbance loading assembly includes a second servo hydraulic actuator, a fifth linear servo electric cylinder, a sixth linear servo electric cylinder, a seventh linear servo electric cylinder, an eighth linear servo electric cylinder, a lower rigid support cylinder, and a lower rigid support plate. The lower rigid support cylinder is coaxially and vertically fixed on the lower servo electric turntable. The second servo hydraulic actuator is coaxially fixed on the inner side of the lower rigid support cylinder. The lower rigid support plate is fixedly installed at the top opening of the lower rigid support cylinder. The fifth, sixth, seventh, and eighth linear servo electric cylinders are all horizontally fixed on the edge of the lower rigid support plate and are evenly distributed in sequence along the circumferential direction.

[0013] The first servo hydraulic actuator and the second servo hydraulic actuator are coaxially distributed; the first linear servo electric cylinder is located directly above the fifth linear servo electric cylinder; the second linear servo electric cylinder is located directly above the sixth linear servo electric cylinder; the third linear servo electric cylinder is located directly above the seventh linear servo electric cylinder; and the fourth linear servo electric cylinder is located directly above the eighth linear servo electric cylinder.

[0014] A hydraulic oil source and an oil cooling mechanism are provided above the top beam of the frame body; the oil supply end of the hydraulic oil source is connected to the oil receiving end of the first servo hydraulic actuator and the second servo hydraulic actuator, and the oil discharge end of the first servo hydraulic actuator and the second servo hydraulic actuator is connected to the oil return end of the hydraulic oil source through the oil cooling mechanism.

[0015] The three-rigid-type sample fixture includes a first horizontal rigid pad, a second horizontal rigid pad, a third horizontal rigid pad, a fourth horizontal rigid pad, a first vertical rigid pad, and a second vertical rigid pad. The first and second vertical rigid pads have the same structure and are both cuboid. The lower surface of the first vertical rigid pad is in abutting contact with the upper surface of the rock sample, and the upper surface of the first vertical rigid pad is coaxially connected to the piston rod end of the first servo hydraulic actuator via a pressure head. The upper surface of the second vertical rigid pad is in abutting contact with the lower surface of the rock sample, and the lower surface of the second vertical rigid pad is coaxially connected to the piston rod end of the second servo hydraulic actuator via a pressure head. The first, second, third, and fourth horizontal rigid pads are evenly distributed on the rock sample. The sample is surrounded by four horizontal rigid pads. The first, second, third, and fourth horizontal rigid pads have the same structure and all adopt a straight plate structure. A sample clamping boss is provided in the middle of the inner side of the straight plate, an upper loading boss is provided at the upper end of the outer side of the straight plate, and a lower loading boss is provided at the lower end of the outer side of the straight plate. The sample clamping boss is in abutting contact with the side of the rock sample. The upper loading boss is connected to the end of the power output rod of the first, second, third, or fourth linear servo electric cylinder through a pressure head. The lower loading boss is connected to the end of the power output rod of the fifth, sixth, seventh, or eighth linear servo electric cylinder through a pressure head.

[0016] A hydraulic fracturing channel is provided inside the first or second vertical rigid pad; a hydraulic fracturing hole is provided inside the rock sample, and a hydraulic fracturing pipe is provided between the hydraulic fracturing hole and the hydraulic fracturing channel.

[0017] The radiation emission unit includes a radiation emitter, a transmitter lifting platform, a transmitter lifting actuator, and a transmitter bracket; the transmitter bracket is vertically mounted on a horizontal sliding attitude adjustment mechanism, and the transmitter bracket has a horizontal degree of freedom of movement on the base; the transmitter lifting actuator is mounted on the transmitter bracket; the transmitter lifting platform is mounted on the transmitter lifting actuator, and the transmitter lifting platform has a lifting degree of freedom of movement on the transmitter bracket; the radiation emitter is mounted on the transmitter lifting platform.

[0018] The radiation receiving unit includes a radiation receiver, a receiver lifting platform, a receiver lifting actuator, and a receiver bracket; the receiver bracket is vertically mounted on a horizontal sliding attitude adjustment mechanism, and has a horizontal degree of freedom of movement on the base; the receiver lifting actuator is mounted on the receiver bracket; the receiver lifting platform is mounted on the receiver lifting actuator, and has a vertical degree of freedom of movement on the receiver bracket; the radiation receiver is mounted on the receiver lifting platform; the rock sample on the sample clamping boss of the three-rigid-type sample fixture and the sample clamping boss inside it are located on the same straight line as the radiation emitter and the radiation receiver.

[0019] The beneficial effects of this invention are:

[0020] The deep engineering dynamic disturbance hard rock true triaxial CT real-time scanning experimental device of the present invention can realize real-time CT scanning of the entire process of dynamic disturbance true triaxial experiment, and can obtain information on the development process of internal rock cracks at different loading times. It overcomes the problems of traditional true triaxial experiments, such as the inability to directly observe rock fracture and the large errors and inaccurate results of other monitoring methods. It can carry out true triaxial experiments of stress release and dynamic disturbance coupling, which can simulate the working conditions of deep engineering hydraulic fracturing technology to prevent dynamic disasters, and obtain the evolution process of internal rock cracks at different times through real-time CT scanning, so as to achieve accurate three-dimensional reconstruction of the internal rock crack evolution process. It can carry out rock mechanics experiments such as three-direction dynamic disturbance true triaxial experiment, long-term fatigue true triaxial experiment, and hydraulic fracturing dynamic disturbance coupled true triaxial experiment, and realize real-time CT scanning and three-dimensional reconstruction during the experiment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a real-time triaxial CT scanning experimental device for deep engineering dynamic disturbance hard rock according to the present invention;

[0022] Figure 2 This is a schematic diagram of the true triaxial loading mechanism of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of the three-rigid-type sample holder of the present invention;

[0024] Figure 4 This is a cross-sectional view of the three-rigid-type sample fixture of the present invention;

[0025] Figure 5 These are schematic diagrams of the structure of the first / second / third / fourth horizontal rigid pads of the present invention;

[0026] In the diagram, 1—base, 2—support, 3—frame, 4—upper servo electric turntable, 5—lower servo electric turntable, 6—three-rigid sample fixture, 7—first servo hydraulic actuator, 8—first linear servo electric cylinder, 9—second linear servo electric cylinder, 10—third linear servo electric cylinder, 11—fourth linear servo electric cylinder, 12—upper rigid support cylinder, 13—upper rigid support plate, 14—second servo hydraulic actuator, 15—fifth linear servo electric cylinder, 16—sixth linear servo electric cylinder, 17—seventh linear servo electric cylinder, 18—eighth linear servo electric cylinder, 19—lower rigid support cylinder, 20—lower rigid support plate, 21—hydraulic oil source, 22—oil Liquid cooling mechanism, 23—first horizontal rigid pad, 24—second horizontal rigid pad, 25—third horizontal rigid pad, 26—fourth horizontal rigid pad, 27—first vertical rigid pad, 28—second vertical rigid pad, 29—rock sample, 30—sample clamping boss, 31—upper loading boss, 32—lower loading boss, 33—hydraulic fracturing channel, 34—hydraulic fracturing hole, 35—hydraulic fracturing pipe, 36—radiation transmitter, 37—transmitter lifting platform, 38—transmitter lifting actuator, 39—transmitter bracket, 40—radiation receiver, 41—receiver lifting platform, 42—receiver lifting actuator, 43—receiver bracket, 44—horizontal sliding attitude adjustment mechanism. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] like Figures 1-5 As shown, a real-time triaxial CT scanning experimental device for deep engineering dynamic disturbance hard rock includes a base 1, a true triaxial loading mechanism, and a real-time CT scanning mechanism. The base 1 is horizontally fixed on the ground. The true triaxial loading mechanism is fixedly installed in the middle of the base 1. The real-time CT scanning mechanism includes a radiation emitting unit and a radiation receiving unit, with the true triaxial loading mechanism located between the radiation emitting unit and the radiation receiving unit. A horizontal sliding attitude adjustment mechanism 44 is provided on the upper surface of the base 1, and both the radiation emitting unit and the radiation receiving unit are installed on the horizontal sliding attitude adjustment mechanism 44.

[0029] The true triaxial loading mechanism includes a support 2, a frame 3, an upper dynamic disturbance loading component, an upper servo-electric turntable 4, a lower dynamic disturbance loading component, a lower servo-electric turntable 5, and a three-rigid sample clamp 6. The support 2 is fixedly installed on the upper surface of the base 1. The frame 3 adopts a U-shaped structure and is vertically fixedly installed above the support 2. The upper servo-electric turntable 4 is horizontally arranged in the middle of the top beam of the frame 3. The upper dynamic disturbance loading component is arranged on the upper servo-electric turntable 4. The lower servo-electric turntable 5 is horizontally arranged in the middle of the bottom beam of the frame 3. The lower dynamic disturbance loading component is arranged on the lower servo-electric turntable 5. The three-rigid sample clamp 6 is located between the upper dynamic disturbance loading component and the lower dynamic disturbance loading component.

[0030] The upper dynamic disturbance loading assembly includes a first servo hydraulic actuator 7, a first linear servo electric cylinder 8, a second linear servo electric cylinder 9, a third linear servo electric cylinder 10, a fourth linear servo electric cylinder 11, an upper rigid support cylinder 12, and an upper rigid support plate 13. The upper rigid support cylinder 12 is coaxially and vertically fixed on the upper servo electric turntable 4. The first servo hydraulic actuator 7 is coaxially fixed on the inner side of the upper rigid support cylinder 12. The upper rigid support plate 13 is fixedly installed at the bottom opening of the upper rigid support cylinder 12. The first linear servo electric cylinder 8, the second linear servo electric cylinder 9, the third linear servo electric cylinder 10, and the fourth linear servo electric cylinder 11 are all horizontally fixed on the edge of the upper rigid support plate 13 and are evenly distributed in sequence along the circumferential direction.

[0031] The lower dynamic disturbance loading assembly includes a second servo hydraulic actuator 14, a fifth linear servo electric cylinder 15, a sixth linear servo electric cylinder 16, a seventh linear servo electric cylinder 17, an eighth linear servo electric cylinder 18, a lower rigid support cylinder 19, and a lower rigid support plate 20. The lower rigid support cylinder 19 is coaxially and vertically fixed on the lower servo electric turntable 5. The second servo hydraulic actuator 14 is coaxially fixed on the inner side of the lower rigid support cylinder 19. The lower rigid support plate 20 is fixedly installed at the top opening of the lower rigid support cylinder 19. The fifth linear servo electric cylinder 15, the sixth linear servo electric cylinder 16, the seventh linear servo electric cylinder 17, and the eighth linear servo electric cylinder 18 are all horizontally fixed on the edge of the lower rigid support plate 20 and are evenly distributed in sequence along the circumferential direction.

[0032] The first servo hydraulic actuator 7 and the second servo hydraulic actuator 14 are coaxially distributed; the first linear servo electric cylinder 8 is located directly above the fifth linear servo electric cylinder 15; the second linear servo electric cylinder 9 is located directly above the sixth linear servo electric cylinder 16; the third linear servo electric cylinder 10 is located directly above the seventh linear servo electric cylinder 17; and the fourth linear servo electric cylinder 11 is located directly above the eighth linear servo electric cylinder 18.

[0033] A hydraulic oil source 21 and an oil cooling mechanism 22 are provided above the top beam of the frame body 3; the oil supply end of the hydraulic oil source 21 is connected to the oil receiving end of the first servo hydraulic actuator 7 and the second servo hydraulic actuator 14, and the oil discharge end of the first servo hydraulic actuator 7 and the second servo hydraulic actuator 14 is connected to the oil return end of the hydraulic oil source 21 through the oil cooling mechanism 22.

[0034] The three-rigid-type sample holder 6 includes a first horizontal rigid pad 23, a second horizontal rigid pad 24, a third horizontal rigid pad 25, a fourth horizontal rigid pad 26, a first vertical rigid pad 27, and a second vertical rigid pad 28. The first vertical rigid pad 27 and the second vertical rigid pad 28 have the same structure and both adopt a cuboid structure. The lower surface of the first vertical rigid pad 27 is in abutting contact with the upper surface of the rock sample 29, and the upper surface of the first vertical rigid pad 27 is coaxially connected to the piston rod end of the first servo hydraulic actuator 7 through a pressure head. The upper surface of the second vertical rigid pad 28 is in abutting contact with the lower surface of the rock sample 29, and the lower surface of the second vertical rigid pad 28 is coaxially connected to the piston rod end of the second servo hydraulic actuator 14 through a pressure head. The first horizontal rigid pad 23, the second horizontal rigid pad 24, the third horizontal rigid pad 25, and the fourth horizontal rigid pad 26 are evenly distributed on the rock sample. The four sides of the sample 29; the first horizontal rigid pad 23, the second horizontal rigid pad 24, the third horizontal rigid pad 25 and the fourth horizontal rigid pad 26 have the same structure and all adopt a straight plate structure. A sample clamping boss 30 is provided in the middle of the inner side of the straight plate, an upper loading boss 31 is provided at the upper end of the outer side of the straight plate, and a lower loading boss 32 is provided at the lower end of the outer side of the straight plate; the sample clamping boss 30 is in abutting contact with the side of the rock sample 29; the upper loading boss 31 is connected to the end of the power output rod of the first linear servo electric cylinder 8, the second linear servo electric cylinder 9, the third linear servo electric cylinder 10 or the fourth linear servo electric cylinder 11 through a pressure head; the lower loading boss 32 is connected to the end of the power output rod of the fifth linear servo electric cylinder 15, the sixth linear servo electric cylinder 16, the seventh linear servo electric cylinder 17 or the eighth linear servo electric cylinder 18 through a pressure head.

[0035] A hydraulic fracturing channel 33 is provided inside the first vertical rigid pad 27 or the second vertical rigid pad 28; a hydraulic fracturing hole 34 is provided inside the rock sample 29; and a hydraulic fracturing pipe 35 is provided between the hydraulic fracturing hole 34 and the hydraulic fracturing channel 33.

[0036] The radiation emission unit includes a radiation emitter 36, a transmitter lifting platform 37, a transmitter lifting actuator 38, and a transmitter bracket 39. The transmitter bracket 39 is vertically mounted on a horizontal sliding attitude adjustment mechanism 44 and has a horizontal degree of freedom of movement on the base 1. The transmitter lifting actuator 38 is mounted on the transmitter bracket 39. The transmitter lifting platform 37 is mounted on the transmitter lifting actuator 38 and has a lifting degree of freedom of movement on the transmitter bracket 39. The radiation emitter 36 is mounted on the transmitter lifting platform 37.

[0037] The radiation receiving unit includes a radiation receiver 40, a receiver lifting platform 41, a receiver lifting actuator 42, and a receiver bracket 43. The receiver bracket 43 is vertically mounted on a horizontal sliding and adjusting mechanism 44, and has a horizontal degree of freedom of movement on the base 1. The receiver lifting actuator 42 is mounted on the receiver bracket 43. The receiver lifting platform 41 is mounted on the receiver lifting actuator 42, and has a lifting degree of freedom of movement on the receiver bracket 43. The radiation receiver 40 is mounted on the receiver lifting platform 41. The sample clamping boss 30 on the three-rigid sample fixture 6 and the rock sample 29 inside it are located on the same straight line as the radiation emitter 36 and the radiation receiver 40.

[0038] The following description, in conjunction with the accompanying drawings, illustrates the usage of this invention:

[0039] In this embodiment, the horizontal sliding attitude adjustment mechanism 44, the transmitter lifting actuator 38, and the receiver lifting actuator 42 all adopt motor-driven lead screw slide rail mechanisms. The first servo hydraulic actuator 7 and the second servo hydraulic actuator 14 cooperate to apply the maximum principal stress. The first linear servo electric cylinder 8 cooperates with the third linear servo electric cylinder 10, the fifth linear servo electric cylinder 15 cooperates with the seventh linear servo electric cylinder 17 to apply the intermediate principal stress. The second linear servo electric cylinder 9 cooperates with the fourth linear servo electric cylinder 11, the sixth linear servo electric cylinder 16 cooperates with the eighth linear servo electric cylinder 18 to apply the minimum principal stress.

[0040] Before the experiment, the rock sample 29 and the three-rigid sample clamp 6 were assembled together to form a rock sample clamp assembly. Three sets of LVDT displacement sensors were installed on the three-rigid sample clamp 6 of the rock sample clamp assembly to measure the deformation of the rock sample 29 during the experiment.

[0041] The rock sample clamp assembly is then placed above the piston rod tip of the second servo hydraulic actuator 14, so that the second vertical rigid pad 28 of the rock sample clamp assembly is placed on the upper surface of the piston rod tip of the second servo hydraulic actuator 14. Then, the extension and retraction position of the piston rod of the second servo hydraulic actuator 14 is adjusted so that the lower loading boss 32 of the rock sample clamp assembly is at the same height as the fifth linear servo electric cylinder 15, the sixth linear servo electric cylinder 16, the seventh linear servo electric cylinder 17, and the eighth linear servo electric cylinder 18.

[0042] After the height of the rock sample clamp assembly is adjusted, the piston rod of the first servo hydraulic actuator 7 is controlled to extend downward until the piston rod end pressure head of the first servo hydraulic actuator 7 comes into contact with the upper surface of the first vertical rigid pad 27 of the rock sample clamp assembly, and the vertical axial pre-clamping is achieved.

[0043] After the rock sample clamp assembly completes the vertical pre-clamping, the power output rods of the first linear servo electric cylinder 8, the second linear servo electric cylinder 9, the third linear servo electric cylinder 10, and the fourth linear servo electric cylinder 11 are simultaneously extended until the pressure head at the end of the power output rod simultaneously makes contact with the four upper loading bosses 31 of the rock sample clamp assembly from four directions. At the same time, the power output rods of the fifth linear servo electric cylinder 15, the sixth linear servo electric cylinder 16, the seventh linear servo electric cylinder 17, and the eighth linear servo electric cylinder 18 are simultaneously extended until the pressure head at the end of the power output rod simultaneously makes contact with the four lower loading bosses 32 of the rock sample clamp assembly from four directions, finally achieving horizontal pre-clamping.

[0044] Once the rock sample clamp assembly is pre-clamped in three directions, true triaxial tests of dynamic disturbance in three directions and long-term fatigue true triaxial tests can be carried out as needed. If a true triaxial test of stress release and dynamic disturbance coupling or a true triaxial test of hydraulic fracturing dynamic disturbance coupling is to be carried out, the external hydraulic fracturing system needs to be connected to the hydraulic fracturing channel 33 before the hydraulic fracturing dynamic disturbance coupling true triaxial test can be carried out.

[0045] During the experiment, the height of the X-ray transmitter 36 and the X-ray receiver 40 were first adjusted so that the X-ray transmitter 36 and the X-ray receiver 40 were aligned with the rock sample 29 inside the rock sample fixture assembly. Then, the distance between the X-ray transmitter 36 and the X-ray receiver 40, as well as the distance between them and the rock sample fixture assembly, was adjusted to achieve the optimal distance.

[0046] After the positions of the X-ray transmitter 36 and the X-ray receiver 40 are adjusted, as the experiment proceeds, the upper servo electric turntable 4 and the lower servo electric turntable 5 are started synchronously and in the same direction, thereby driving the upper dynamic disturbance loading component, the lower dynamic disturbance loading component and the rock sample clamp assembly between them to rotate synchronously. At the same time, the X-ray transmitter 36 and the X-ray receiver 40 are started, and finally, real-time CT scanning and three-dimensional reconstruction are realized during the experiment.

[0047] Specifically, once the maximum principal stress, intermediate principal stress, and minimum principal stress reach their target values, if true triaxial tests of dynamic disturbances in three directions or long-term fatigue true triaxial tests are conducted, corresponding disturbance frequencies and amplitudes can be set based on multi-source dynamic disturbance data obtained from on-site monitoring of deep engineering projects. This allows for the simulation of common disturbance types during tunnel construction and operation, including seismic stress waves, rockburst shock waves, blasting disturbance waves, train running dynamic loads, and TBM construction vibration waves. By changing the combination of disturbance amplitude and frequency, the influence of different dynamic disturbance characteristics on rock strength, crack evolution, and failure modes can be systematically studied.

[0048] Furthermore, once the maximum principal stress, intermediate principal stress, and minimum principal stress reach their target values, if a true triaxial experiment on the coupling effect of stress release and dynamic disturbance, or a true triaxial experiment on the coupling effect of hydraulic fracturing and dynamic disturbance, is conducted, high-pressure hydraulic fracturing can be performed according to the experimental settings to complete the stress release within the rock. Simultaneously, disturbances can be applied as needed to simulate common disturbance types encountered during tunnel construction and operation, including seismic stress waves, rockburst shock waves, blasting disturbance waves, train running dynamic loads, and TBM construction vibration waves. By changing the combination of disturbance amplitude and frequency, the stress release effect of hydraulic fracturing and its coupling effect with dynamic disturbances can be systematically studied.

[0049] At different stages after the application of dynamic disturbance, according to experimental needs, at any moment of loading, real-time CT scanning can be completed by synchronous rotation of the upper dynamic disturbance loading component, the lower dynamic disturbance loading component, and the rock sample clamp assembly between them. The scanning results can be used to achieve three-dimensional reconstruction. The imaging results and the loading process can be recorded synchronously, thus enabling high-resolution non-destructive three-dimensional visualization observation throughout the entire process of microcrack initiation, propagation, and penetration.

[0050] The solutions in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the present invention are included in the scope of protection of the present invention.

Claims

1. A real-time triaxial CT scanning experimental device for deep engineering dynamic disturbance hard rock, characterized in that: The system includes a base, a true triaxial loading mechanism, and a real-time CT scanning mechanism. The base is horizontally and fixedly mounted on the ground. The true triaxial loading mechanism is fixedly mounted in the middle of the base. The real-time CT scanning mechanism includes a radiation emitting unit and a radiation receiving unit, with the true triaxial loading mechanism located between the radiation emitting unit and the radiation receiving unit. A horizontal sliding attitude adjustment mechanism is provided on the upper surface of the base, and both the radiation emitting unit and the radiation receiving unit are mounted on the horizontal sliding attitude adjustment mechanism. The true triaxial loading mechanism includes a support, a frame, an upper dynamic disturbance loading component, an upper servo-electric turntable, a lower dynamic disturbance loading component, a lower servo-electric turntable, and a three-rigid-type sample clamp. The support is fixedly installed on the upper surface of the base. The frame adopts a U-shaped structure and is vertically fixedly installed above the support. The upper servo-electric turntable is horizontally positioned in the middle of the top beam of the frame. The upper dynamic disturbance loading component is positioned on the upper servo-electric turntable. The lower servo-electric turntable is horizontally positioned in the middle of the bottom beam of the frame. The lower dynamic disturbance loading component is positioned on the lower servo-electric turntable. The three-rigid-type sample clamp is located between the upper and lower dynamic disturbance loading components. The upper dynamic disturbance loading assembly includes a first servo hydraulic actuator, a first linear servo electric cylinder, a second linear servo electric cylinder, a third linear servo electric cylinder, a fourth linear servo electric cylinder, an upper rigid support cylinder, and an upper rigid support plate. The upper rigid support cylinder is coaxially and vertically fixed on the upper servo electric turntable. The first servo hydraulic actuator is coaxially fixed on the inner side of the upper rigid support cylinder. The upper rigid support plate is fixedly installed at the bottom opening of the upper rigid support cylinder. The first, second, third, and fourth linear servo electric cylinders are all horizontally fixed on the edge of the upper rigid support plate and are evenly distributed in sequence along the circumferential direction. The lower dynamic disturbance loading assembly includes a second servo hydraulic actuator, a fifth linear servo electric cylinder, a sixth linear servo electric cylinder, a seventh linear servo electric cylinder, an eighth linear servo electric cylinder, a lower rigid support cylinder, and a lower rigid support plate. The lower rigid support cylinder is coaxially and vertically fixed on the lower servo electric turntable. The second servo hydraulic actuator is coaxially fixed on the inner side of the lower rigid support cylinder. The lower rigid support plate is fixedly installed at the top opening of the lower rigid support cylinder. The fifth, sixth, seventh, and eighth linear servo electric cylinders are all horizontally fixed on the edge of the lower rigid support plate and are evenly distributed in sequence along the circumferential direction. The first servo hydraulic actuator and the second servo hydraulic actuator are coaxially distributed; the first linear servo electric cylinder is located directly above the fifth linear servo electric cylinder; the second linear servo electric cylinder is located directly above the sixth linear servo electric cylinder; the third linear servo electric cylinder is located directly above the seventh linear servo electric cylinder; and the fourth linear servo electric cylinder is located directly above the eighth linear servo electric cylinder.

2. The experimental device for real-time triaxial CT scanning of hard rock under dynamic disturbance in deep engineering as described in claim 1, characterized in that: A hydraulic oil source and an oil cooling mechanism are provided above the top beam of the frame body; the oil supply end of the hydraulic oil source is connected to the oil receiving end of the first servo hydraulic actuator and the second servo hydraulic actuator, and the oil discharge end of the first servo hydraulic actuator and the second servo hydraulic actuator is connected to the oil return end of the hydraulic oil source through the oil cooling mechanism.

3. The experimental device for real-time triaxial CT scanning of hard rock under dynamic disturbance in deep engineering as described in claim 1, characterized in that: The three-rigid-type sample fixture includes a first horizontal rigid pad, a second horizontal rigid pad, a third horizontal rigid pad, a fourth horizontal rigid pad, a first vertical rigid pad, and a second vertical rigid pad. The first and second vertical rigid pads have the same structure and are both cuboid. The lower surface of the first vertical rigid pad is in abutting contact with the upper surface of the rock sample, and the upper surface of the first vertical rigid pad is coaxially connected to the piston rod end of the first servo hydraulic actuator via a pressure head. The upper surface of the second vertical rigid pad is in abutting contact with the lower surface of the rock sample, and the lower surface of the second vertical rigid pad is coaxially connected to the piston rod end of the second servo hydraulic actuator via a pressure head. The first, second, third, and fourth horizontal rigid pads are evenly distributed on the rock sample. The sample is surrounded by four horizontal rigid pads. The first, second, third, and fourth horizontal rigid pads have the same structure and all adopt a straight plate structure. A sample clamping boss is provided in the middle of the inner side of the straight plate, an upper loading boss is provided at the upper end of the outer side of the straight plate, and a lower loading boss is provided at the lower end of the outer side of the straight plate. The sample clamping boss is in abutting contact with the side of the rock sample. The upper loading boss is connected to the end of the power output rod of the first, second, third, or fourth linear servo electric cylinder through a pressure head. The lower loading boss is connected to the end of the power output rod of the fifth, sixth, seventh, or eighth linear servo electric cylinder through a pressure head.

4. The experimental device for real-time triaxial CT scanning of hard rock under dynamic disturbance in deep engineering as described in claim 3, characterized in that: A hydraulic fracturing channel is provided inside the first or second vertical rigid pad; a hydraulic fracturing hole is provided inside the rock sample, and a hydraulic fracturing pipe is provided between the hydraulic fracturing hole and the hydraulic fracturing channel.

5. The experimental device for real-time triaxial CT scanning of hard rock under dynamic disturbance in deep engineering as described in claim 3, characterized in that: The radiation emission unit includes a radiation emitter, a emitter lifting platform, a emitter lifting actuator, and a emitter bracket; the emitter bracket is vertically mounted on a horizontal sliding attitude adjustment mechanism, and the emitter bracket has a degree of freedom of horizontal movement on the base; the emitter lifting actuator is mounted on the emitter bracket; The transmitter lifting platform is mounted on the transmitter lifting actuator, and the transmitter lifting platform has the freedom of lifting and moving on the transmitter support; the X-ray transmitter is mounted on the transmitter lifting platform.

6. The experimental device for real-time triaxial CT scanning of hard rock under dynamic disturbance in deep engineering as described in claim 5, characterized in that: The radiation receiving unit includes a radiation receiver, a receiver lifting platform, a receiver lifting actuator, and a receiver bracket; the receiver bracket is vertically mounted on a horizontal sliding attitude adjustment mechanism, and has a horizontal degree of freedom of movement on the base; the receiver lifting actuator is mounted on the receiver bracket; the receiver lifting platform is mounted on the receiver lifting actuator, and has a vertical degree of freedom of movement on the receiver bracket; the radiation receiver is mounted on the receiver lifting platform; the rock sample on the sample clamping boss of the three-rigid-type sample fixture and the sample clamping boss inside it are located on the same straight line as the radiation emitter and the radiation receiver.

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