A simulation device and method for spontaneous abrupt changes in rockburst in high-stress tunnels

Abstract

This invention relates to a simulation device and method for spontaneous abrupt changes in rockburst in high-stress tunnels. The device includes a stress relay device, a multi-source information monitoring system, and a biaxial rock mechanics testing system. The multi-source information monitoring system is connected to the stress relay device, which is mounted on the loading plate of the biaxial rock mechanics testing system. The loading plate is pressed onto the rock sample. The stress relay device includes a connecting plate, an outer sleeve, a spring, a piston rod, and an end cap. The two end faces of the connecting plate are respectively connected to the loading plate and the outer sleeve of the biaxial rock mechanics testing system. The end cap is located on one side of the other end face of the outer sleeve. One end of the piston rod is connected to the end cap, and the spring is sleeved on the outside of the piston rod. Compared with existing technologies, this invention has the advantages of simulating spontaneous static-dynamic abrupt changes in rockburst under quasi-static displacement loading conditions and reproducing the violent block throwing phenomenon in local areas of the tunnel model.

Description

Technical Field

[0001] This invention relates to geotechnical engineering, and in particular to a simulation device and method for spontaneous abrupt changes in rockburst in high-stress tunnels. Background Technology

[0002] Rockburst is a common rock dynamic disaster encountered during the excavation of tunnels in high-stress hard rock. It is characterized by the sudden and violent throwing of localized rock blocks from the tunnel's exposed surface into the tunnel, often causing casualties and damage to machinery and equipment. In recent years, rockburst disasters have occurred frequently during the construction of major infrastructure projects such as transportation tunnels, water diversion tunnels, and underground protection projects, becoming a serious obstacle to the smooth progress of these projects.

[0003] Clarifying the mechanism of rockburst is a necessary prerequisite for rockburst prevention; however, its mechanism remains a "global challenge," with one of the key difficulties being how to explain the spatiotemporal suddenness of rockbursts. This spatiotemporal suddenness makes it difficult to predict when and from which a rockburst will occur, making it difficult to avoid at construction sites. The fundamental scientific reason for this lies in the spontaneous nature of rockbursts. The spatiotemporal suddenness of rockbursts can be understood as a rockburst occurring after tunnel excavation, under conditions of no significant dynamic disturbance, due to stress adjustment in the surrounding rock under high ground stress. Spatiotemporal suddenness is the prominent characteristic of this type of rockburst, and the continuous high ground stress and the localized tangential stress concentration caused by stress adjustment in the surrounding rock after excavation are the main causes inducing this type of rockburst. Therefore, how to experimentally simulate spontaneous rockbursts under static conditions of continuous ground stress is a necessary prerequisite for exploring its mechanism.

[0004] Existing experimental methods for simulating rockburst phenomena can be divided into two categories: First, considering the influence of dynamic disturbances, a static-dynamic combined loading method using static and dynamic loads can successfully simulate the rockburst block throwing phenomenon. In this method, the dynamic load plays a crucial role, whereas spontaneous rockbursts are generated solely by static loads and lack this dynamic effect. Second, only static loading simulation using a testing machine is used to load the sample. This method often results in static brittle failures such as spalling, exfoliation, and slab cracking in tunnels, with limited dynamic damage from block throwing. For example, application publication number CN118424893A discloses a true triaxial experimental device and method for real-time monitoring of tunnel surrounding rock damage. This device provides axial pressure along the X, Y, and Z axes to the tunnel model using a combined indenter; real-time monitoring of deformation data of the tunnel model using deformation sensing components; real-time monitoring of rock fracture damage data of the tunnel model using acoustic emission sensing components; and real-time monitoring of the damage to the tunnel inner wall using image acquisition components. Both of the above methods are difficult to simulate the spontaneous dynamic block throwing phenomenon of rockbursts, which makes the study of the spontaneous disaster mechanism of rockbursts difficult.

[0005] In summary, the technical problem that needs to be solved is how to design a simulation device and method that can provide continuous static conditions for spontaneous abrupt changes in rockburst in high-stress tunnels. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology in that it cannot provide continuous static conditions, and to provide a simulation device and method for spontaneous abrupt changes in rockburst in high-stress tunnels. The objective of this invention can be achieved through the following technical solutions.

[0007] According to one aspect of the present invention, a simulation device for spontaneous abrupt changes in rockburst in high-stress tunnels is provided, which uses rock samples for simulation. The device includes a stress relay device, a multi-source information monitoring system, and a biaxial rock mechanics testing system. Multiple stress relay devices are provided. The multi-source information monitoring system is connected to the stress relay devices, and the stress relay devices are mounted on a loading plate of the biaxial rock mechanics testing system. The loading plate is pressed onto the rock sample. The stress relay device includes a connecting plate, an outer sleeve, a spring, a piston rod, and an end cap; one end face of the connecting plate is connected to the loading plate of the biaxial rock mechanics testing system, and the other end face is connected to one end face of the outer sleeve; the end cap is located on one side of the other end face of the outer sleeve; one end of the piston rod is connected to the end cap, and the spring is sleeved on the outside of the piston rod; the piston rod, the pressure head, and the spring are located inside the outer sleeve.

[0008] As a preferred technical solution, the rock sample is a hexahedron with a circular hole in the center and a random speckle pattern evenly sprayed on its surface; the stress relay device consists of four parts, which are respectively installed on the four sides of the rock sample.

[0009] As a preferred technical solution, the stress relay device is locked onto the biaxial rock mechanics testing system by a G-clamp.

[0010] As a preferred technical solution, both ends of the spring are in a plane within a range of 0 to 360°; the free length of the spring is greater than the length of the piston rod, and the length of the piston rod is not less than the compression length of the spring.

[0011] As a preferred technical solution, the outer surface of the piston rod is further fitted with a directional disc, the outer surface of the directional disc is provided with circumferentially distributed protrusions, and the inner surface of the outer sleeve is provided with circumferentially distributed grooves, the protrusions and grooves cooperating with each other; the sum of the free length of the spring and the thickness of the directional disc is less than the length of the outer sleeve.

[0012] As a preferred technical solution, the pressure head is provided with scale lines.

[0013] As a preferred technical solution, the multi-source information monitoring system includes an accelerometer, a displacement sensor, an acoustic emission probe, a high-speed camera, an industrial camera, and a dynamic data acquisition instrument; the sampling frequency of the displacement sensor, the industrial camera, and the high-speed camera is 1000Hz. The acceleration sensor and displacement sensor are mounted on the stress relay device, the acoustic emission probe is mounted on the rock sample, the high-speed camera and industrial camera are mounted on one side of the stress relay device and the sample, and the dynamic data acquisition instrument is connected to the acceleration sensor and displacement sensor.

[0014] As a preferred technical solution, the multi-source information monitoring system further includes a light source, which is arranged on the side of the stress relay device close to the camera.

[0015] According to another aspect of the present invention, a simulation method is provided using a simulation device for spontaneous abrupt changes in rockburst in high-stress tunnels, specifically comprising the following steps: Step S1: Secure the two pressure relay devices to the upper pressure head and the side pressure head of the biaxial rock mechanics test system respectively, and place the rock sample at the center of the two base plates. Step S2: Activate the biaxial rock mechanics testing system and compress the two pressure relay devices to a fully closed state. Step S3: The rock sample is continuously loaded using a quasi-static displacement loading method until a rock burst occurs, while the multi-source information monitoring system continuously records data. Step S4: Analyze the transient process of spontaneous rockburst's millisecond-level static-dynamic state change and summarize the catastrophic mechanism of spontaneous rockburst change.

[0016] As a preferred technical solution, in step S3, the loading speed of the biaxial rock mechanics test system is 0.01 mm / s. When the multi-source information monitoring system detects a high-frequency AE signal and a sudden change in displacement, it is determined that a rock burst has occurred.

[0017] Compared with the prior art, the present invention has the following beneficial effects.

[0018] 1) The stress relay component of this invention ensures that the stress acting on the specimen remains under continuous tension during loading, without generating dynamic loads. In conventional hydraulic testing machines, if the specimen fractures even slightly during loading, it causes a transient unloading of the machine's indenter. At this instant, the force exerted on the specimen by the indenter immediately decreases, which does not match the continuous and uninterrupted action of ground stress in real-world conditions. The stress relay component can promptly replenish stress at the moment of unloading, effectively solving this problem and ensuring the continuity of stress action. This invention can simulate spontaneous static-dynamic abrupt changes in rockburst under quasi-static displacement loading conditions, reproducing the violent block throwing phenomenon in localized areas of tunnel models, and solving the problem that existing physical simulation methods often produce static brittle splitting and are difficult to apply to rockbursts.

[0019] 2) The rock sample of this invention is designed as a hexahedron, which facilitates the application of force; the central part has a circular hole, which helps to realize the stress concentration effect in the simulation; the speckle pattern on the surface facilitates the optical monitoring system to capture deformation details, thereby improving the accuracy and repeatability of the experiment.

[0020] 3) The outer sleeve and piston come into contact with each other to form the main force transmission component. Except for the force transmitted by the spring, all other forces loaded by the testing machine are borne by it; the spring plays the role of keeping the transmitted force from becoming loose.

[0021] 4) The G-shaped clamp of the present invention locks the connecting plate of the stress relay device to the loading head of the biaxial rock mechanics test system, so that the stress relay device is rigidly connected to the biaxial rock mechanics test system to simulate the rigid connection between the far-field bedrock and the near-field surrounding rock in engineering.

[0022] 5) The two ends of the spring of this invention are each in a plane within the range of 0 to 360°, which can ensure uniform force application; the free length of the spring is greater than the length of the piston column, but the sum of the free length and the thickness of the directional plate is less than the length of the outer sleeve, thus ensuring that the spring has a certain compression space; the length of the piston column is not less than the compression length when the spring is compressed, ensuring that the spring still has a small amount of compression margin when the stress relay device is fully compressed, which plays the role of keeping the transmitted force from relaxing.

[0023] 6) The protrusions on the outer surface of the directional disc and the grooves on the inner surface of the outer sleeve of this invention work together to provide guidance, enabling precise control of the direction of the stress relay device. The pressure head is equipped with scale lines for easy observation of the spring's compression degree.

[0024] 7) This invention's displacement sensor records minute deformations in the compression direction of the sample in real time, the acoustic emission probe collects acoustic emission signals from micro-fractures, and the high-speed camera captures the transient process of rockburst. The multi-source information monitoring system can comprehensively capture dynamic signals during rockburst occurrence, such as vibration, displacement, and acoustic emission events, providing rich data sources for analyzing abrupt changes. Adding a light source near the camera significantly improves the imaging quality of the high-speed camera, ensuring clear images of sample deformation even under low-light conditions, and enhancing the overall effectiveness of the monitoring system.

[0025] 8) The method of this invention, through a step-by-step loading process, including initial compression and continuous loading until rockburst occurs, effectively induces and records the spontaneous abrupt changes of rockburst, facilitating researchers' systematic analysis of the disaster mechanism and providing theoretical support for practical engineering prevention. The use of a quasi-static displacement loading method and control of the loading rate helps to accurately trigger rockburst events in simulations. Simultaneously, the multi-source information monitoring system can promptly detect abrupt change signals, such as acoustic emission and displacement changes, ensuring the controllability of the experimental process and the integrity of the data. Attached Figure Description

[0026] Figure 1 This invention provides a simulation device for spontaneous abrupt changes in rockburst in high-stress tunnels. Figure 2 This is a schematic diagram of the stress relay device of the present invention.

[0027] Figure 3 This is an exploded view of the stress relay device of the present invention.

[0028] Figure 4 This is a schematic diagram of the engagement of the protrusion and groove in the stress relay device of the present invention.

[0029] Figure 5 This is a flowchart of a simulation method for spontaneous abrupt changes in rockburst in a high-stress tunnel according to the present invention.

[0030] The numbers in the diagram are as follows: 1. Rock sample; 2. Stress relay device; 2-1. End cap; 2-2. Orientation disk; 2-3. Spring; 2-4. Outer sleeve; 2-5. G-clamp; 2-6. Connecting plate; 3. Upper loading plate; 4. Left loading plate; 5. Lower loading plate; 6. Right loading plate; 7. Displacement sensor; 8. Acoustic emission probe; 9. Accelerometer; 10. Light source; 11. Dynamic data acquisition instrument; 12. High-speed camera; 13. Industrial camera; 14. Dedicated computer for data acquisition instrument; 15. Dedicated computer for industrial camera. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] This invention designs a simulation device and method for spontaneous rockburst mutation in high-stress tunnels. It is equipped with a multi-source information monitoring system based on an adaptive discontinuous digital image correlation method, and successfully realizes laboratory simulation of spontaneous rockburst in a tunnel model under quasi-static conditions. It can be used to study the spontaneous mutation process and disaster mechanism of rockburst.

[0033] Example 1 like Figure 1 and Figure 2 As shown, this embodiment provides a simulation device for spontaneous abrupt changes in rockburst in high-stress tunnels, including a stress relay device 2, a multi-source information monitoring system, and a biaxial rock mechanics testing system.

[0034] Rock sample 1 is a hexahedron with a central hole to simulate a tunnel. Its surface is uniformly sprayed with random speckle patterns to facilitate subsequent image recognition and displacement field calculation. Four stress relay devices 2 are installed on the four sides of rock sample 1. Specifically, a hexahedron structure of 10cm × 10cm × 5cm is selected, with a central hole diameter of 3cm to ensure significant stress concentration.

[0035] Multiple stress relay devices 2 are respectively locked to the upper loading plate 3, left loading plate 4, lower loading plate 5, and right loading plate 6 of the biaxial rock mechanics testing system via G-clamps 2-5. That is, the G-clamps 2-5 clamp the connecting plate 2-6 of the stress relay device 2 and the loading plate of the biaxial rock mechanics testing system, located between the loading plate of the testing machine and the specimen, thus rigidly connecting the stress relay device 2 to the biaxial rock mechanics testing system. Figure 3As shown, the stress relay device 2 includes a connecting plate 2-6, an outer sleeve 2-4, a spring 2-3, a piston rod, a directional disc 2-2, and an end cap 2-1. One end face of the connecting plate 2-6 is connected to the loading plate of the biaxial rock mechanics testing system, and the other end face is connected to one end face of the outer sleeve 2-4; the end cap 2-1 is located on one side of the other end face of the outer sleeve 2-4; one end of the piston rod is connected to the end cap 2-1, and the directional disc 2-2 and the spring 2-3 are sleeved on the outside of the piston rod; the piston rod, the indenter, the directional disc 2-2, and the spring 2-3 are all located inside the outer sleeve 2-4. The connecting plate 2-6 and the outer sleeve 2-4 are an integral structure, and the connecting plate 2-6 is made into a circle or square shape, the same as the indenter of the testing machine; the diameter of the outer sleeve 2-4 is slightly smaller than that of the connecting plate 2-6, and the outer sleeve 2-4 has a certain thickness; the piston rod, the directional disc 2-2, the indenter, and the loading plate are an integral structure.

[0036] like Figure 4 As shown, the directional disc 2-2 is a thick circular disc with four small semi-circular protrusions at the 0, 3, 6, and 9 o'clock positions on its outer edge. Correspondingly, the outer sleeve 2-4 has four matching semi-circular grooves. The protrusions and grooves match to form a guide rail, allowing for precise control of the orientation of the stress relay device 2.

[0037] Both ends of spring 2-3 are strictly flat, and either end lies in a single plane within a range of 0 to 360°. Spring 2-3 has a relatively large elastic modulus k, and its free length l0 is greater than the length L of the piston rod, but the sum of l0 and the thickness T of the guide plate 2-2 is less than the depth D of the outer sleeve 2-4; the length L of the piston rod is not less than the compressed length of spring 2-3 (the shortest compressed length of spring 2-3). s This ensures that when the stress relay device 2 is fully compressed, the spring 2-3 still has a small amount of compression margin, so that the outer sleeve 2-4 and the piston come into contact with each other to form the main force transmission component, while the spring 2-3 plays the role of keeping the transmitted force from relaxing.

[0038] The pressure head has millimeter-resolution scale lines, making it easy to observe the degree of compression of springs 2-3.

[0039] The multi-source information monitoring system includes an accelerometer 9, a displacement sensor 7, an acoustic emission probe 8, a high-speed camera 12, an industrial camera 13, a dynamic data acquisition instrument 11, a light source 10, a dedicated computer for the acquisition instrument 14, and a dedicated computer for the industrial camera 15; the sampling frequency of the displacement sensor 7 and the high-speed camera 12 is 1000Hz; the displacement sensor 7 can be either an LVDT displacement sensor 7 or a laser displacement sensor 7.

[0040] Accelerometer 9 and displacement sensor 7 are mounted on the connecting plates 2-6 of stress relay device 2; acoustic emission probe 8 is mounted on the eight apex corners of rock sample 1; high-speed camera 12 is mounted on one side of stress relay device 2 and sample, and dedicated computer 14 is connected to high-speed camera 12; dynamic data acquisition device 11 is connected to accelerometer 9 and displacement sensor 7 for data acquisition; light source 10 is arranged on the side of stress relay device 2 near high-speed camera 12; industrial camera 13 is mounted on one side of stress relay device 2 and sample, and dedicated computer 15 is connected to industrial camera 13. The sampling frequency of laser displacement sensor 7 and high-speed camera 12 reaches 1000Hz. High-speed camera 12 is used for DIC (Digital Image Correlation, a non-contact full-field measurement technology based on optical principles, which tracks the random speckle pattern on the surface of an object through a high-speed camera, calculates the image matching degree before and after deformation, and accurately measures the displacement, strain, vibration and deformation of the entire field) detection, and industrial camera 13 is used to record rockburst damage phenomena.

[0041] The biaxial rock mechanics testing system is a high-precision electro-hydraulic servo loading testing device designed for fundamental research and engineering applications in rock mechanics. It is primarily used to apply independent, controllable loads in two orthogonal directions (vertical and horizontal) to rock specimens (1), simulating two-dimensional plane stress and strain states in real strata. It can perform various mechanical tests, including biaxial proportional loading, non-proportional loading, single- and biaxial switching, compression-shear composite loading, and cyclic loading. The system typically consists of a high-rigidity loading host, bidirectional independent servo actuators, high-precision force and displacement sensors (7), a closed-loop servo controller, and a data acquisition and analysis unit. It can also integrate a high-frequency acoustic emission monitoring system and other related technologies. Optional modules such as the character image correlation (DIC) non-contact deformation measurement system, pore water pressure loading system, and high and low temperature environmental chamber can accurately acquire the full stress-strain curve, deformation field distribution characteristics, and failure mode of rocks under biaxial stress. Simultaneously, it can capture high-frequency AE signals to achieve crack initiation, propagation path, and fracture source location analysis. Common typical models of this type of equipment include the RMT-150B, RMT-301B, SDSM series biaxial testing machines, as well as the WILLE biaxial rock testing system, MTSBiaxial series, and Instron biaxial mechanical testing system.

[0042] This invention can simulate the spontaneous static-dynamic abrupt change of rockburst under quasi-static displacement loading conditions, reproducing the violent block throwing phenomenon in local tunnel models. It solves the problem that existing physical simulation methods often produce static brittle fracturing and are difficult to apply to rockbursts. The stress relay component ensures that the stress acting on the specimen remains continuously tense during loading without generating dynamic loads. In contrast, conventional hydraulic testing machines, during loading, will cause transient unloading of the machine head if the specimen fractures even slightly. At this instant, the force exerted by the machine head on the specimen immediately decreases, which does not match the continuous and uninterrupted application of ground stress in real-world conditions. The stress relay component can promptly replenish stress at the moment of unloading, effectively solving this problem and ensuring the continuity of stress application.

[0043] The length l0 of spring 2-3 when it is freely extended is greater than the length L of the piston rod, but the sum of l0 and the thickness T of the guide plate 2-2 is less than the depth D of the outer sleeve 2-4, thus ensuring that spring 2-3 has a certain compression space; the length L of the piston rod is not less than the length l of spring 2-3 when it is compressed. s This ensures that when the stress relay device 2 is fully compressed, the spring 2-3 still has a small amount of compression margin, which plays a role in preventing the transmitted force from relaxing. The magnitude of the transmitted force is k(l0-L). The outer sleeve 2-4 and the piston are in contact with each other to form the main force transmission component. In addition to the force transmitted by the spring 2-3, all other forces loaded by the testing machine are borne by it.

[0044] During the test sample loading, four G-clamps 2-5 are used to lock the connecting plate 2-6 of the stress relay device 2 onto the loading head of the testing machine, so that the stress relay device 2 is rigidly connected to the testing machine to simulate the rigid connection between the far-field bedrock and the near-field surrounding rock in engineering.

[0045] Example 2 like Figure 5 As shown in the figure, this embodiment provides a simulation method for spontaneous abrupt changes in rockburst in high-stress tunnels, including the following steps.

[0046] (1) Preparation of tunnel rock model specimens: The rock is cut into hexahedral tunnel model specimens with equal length and width and a circular hole in the middle, and the surface is sprayed with speckle.

[0047] (2) Installation of pressure relay device: Fabricate a pressure relay device to match the biaxial rock mechanics test system.

[0048] (3) Model assembly: Use several G-clamps to lock the two pressure relay devices between the upper pressure head, lower pressure head, left pressure head and right pressure head of the biaxial rock mechanics test system, and place the sample in the center of the base plate; (4) Preloading: Start the testing machine to preload, ensuring that springs 2-3 are initially compressed but have not reached the ultimate compaction state, and ensuring that the device is in a "tight" state.

[0049] (5) Monitoring system setup: A multi-source information monitoring system is set up, including: AD-DIC system (adaptive discontinuous digital image correlation method) for full-field displacement and strain field measurement; LVDT displacement sensor 7 or laser displacement sensor 7 to record small deformations in the compression direction of the sample in real time; acoustic emission probe 8, specifically using AE sensor, with 8 AE sensors symmetrically arranged at the four corners of the sample to collect micro-fracture acoustic emission signals; high-speed camera 12 and dynamic data acquisition instrument 11: the sampling frequency is set to 1000Hz to capture the transient process of rockburst.

[0050] (6) Quasi-static loading and rockburst simulation: Set slow displacement loading (e.g., 0.01 mm / s) in the loading rate control module of the test system to ensure that the loading process meets the quasi-static conditions. As the stress continues to increase, record various monitoring data until the sample fractures violently, the sample hole area is thrown out of the block, accompanied by high-frequency AE signal and displacement change, which indicates that the main rockburst has occurred, and then stop loading.

[0051] (7) Data Analysis and Investigation of Catastrophic Mechanism: Image data of the stages before and after rockburst were extracted, and the crack propagation path and micro-region displacement abrupt changes were obtained using the AD-DIC algorithm. The acoustic emission signals, displacement time history curves and high-speed image sequences were analyzed to reveal the entire process of rockburst from "static loading - crack evolution - transient sudden occurrence". From this, the mechanism of spontaneous rockburst triggered by stress adjustment of the surrounding rock under static conditions can be deduced.

[0052] Using the above method, this embodiment successfully reproduced the spontaneous block throwing phenomenon of rockburst under high ground stress, verified the effectiveness of the pressure relay device in realizing continuous stress loading and spontaneous mutation simulation, and provided a controllable, repeatable and monitorable experimental platform for further revealing the catastrophe mechanism of rockburst.

[0053] This invention employs quasi-static slow displacement loading to provide the sample with a static stress environment without any dynamic action. Under these conditions, rockburst can occur, effectively demonstrating the spontaneity of rockburst. This solves the problem in existing rockburst simulations where rockburst requires dynamic loading or a combination of dynamic and static loading to occur.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A simulation device for spontaneous abrupt change of rockburst in high-stress tunnels, using rock samples (1) for simulation, characterized in that, The device includes a stress relay device (2), a multi-source information monitoring system, and a biaxial rock mechanics testing system; there are multiple stress relay devices (2); the multi-source information monitoring system is connected to the stress relay devices (2), and the stress relay devices (2) are installed on the loading plate of the biaxial rock mechanics testing system; the loading plate is pressed onto the rock sample (1); The stress relay device (2) includes a connecting plate (2-6), an outer sleeve (2-4), a spring (2-3), a piston rod, and an end cap (2-1); one end face of the connecting plate (2-6) is connected to the loading plate of the biaxial rock mechanics test system, and the other end face is connected to one end face of the outer sleeve (2-4); the end cap (2-1) is located on one side of the other end face of the outer sleeve (2-4); one end of the piston rod is connected to the end cap (2-1), and the spring (2-3) is sleeved on the outside of the piston rod; the piston rod, the pressure head, and the spring (2-3) are located inside the outer sleeve (2-4).

2. The simulation device for spontaneous abrupt change of rockburst in a high-stress tunnel according to claim 1, characterized in that, The rock sample (1) is a hexahedron with a round hole in the middle and a random speckle pattern evenly sprayed on the surface; there are four stress relay devices (2), which are installed on the four sides of the rock sample (1).

3. The simulation device for spontaneous abrupt change of rockburst in a high-stress tunnel according to claim 1, characterized in that, The stress relay device (2) is locked onto the biaxial rock mechanics test system by a G-clamp (2-5).

4. The simulation device for spontaneous abrupt change of rockburst in a high-stress tunnel according to claim 1, characterized in that, Both ends of the spring (2-3) are in a plane within a range of 0 to 360°; the free length of the spring (2-3) is greater than the length of the piston rod, and the length of the piston rod is not less than the compression length of the spring (2-3).

5. The simulation device for spontaneous abrupt change of rockburst in a high-stress tunnel according to claim 1, characterized in that, The piston rod is also fitted with a guide plate (2-2) on its outer surface. The guide plate (2-2) has circumferentially distributed protrusions on its outer surface and circumferentially distributed grooves on its inner surface. The protrusions and grooves cooperate with each other. The sum of the free length of the spring (2-3) and the thickness of the guide plate (2-2) is less than the length of the outer sleeve (2-4).

6. The simulation device for spontaneous abrupt change of rockburst in a high-stress tunnel according to claim 1, characterized in that, The pressure head is equipped with graduation lines.

7. The simulation device for spontaneous abrupt change of rockburst in a high-stress tunnel according to claim 1, characterized in that, The multi-source information monitoring system includes an accelerometer (9), a displacement sensor (7), an acoustic emission probe (8), a high-speed camera (12), an industrial camera (13), and a dynamic data acquisition instrument (11); the sampling frequency of the displacement sensor (7), the industrial camera (13), and the high-speed camera (12) is 1000Hz; The acceleration sensor (9) and displacement sensor (7) are mounted on the stress relay device (2), the acoustic emission probe (8) is mounted on the rock sample (1), the high-speed camera (12) and industrial camera (13) are mounted on the stress relay device (2) and the sample side, and the dynamic data acquisition instrument (11) is connected to the acceleration sensor (9) and displacement sensor (7).

8. The simulation device for spontaneous abrupt change of rockburst in a high-stress tunnel according to claim 1, characterized in that, The multi-source information monitoring system also includes a light source (10), which is arranged on the side of the stress relay device (2) near the camera.

9. A simulation method using the simulation device for spontaneous abrupt changes in rockburst in high-stress tunnels as described in any one of claims 1 to 8, characterized in that, Specifically, the following steps are included: Step S1: Secure the two pressure relay devices to the upper pressure head and the side pressure head of the biaxial rock mechanics test system respectively, and place the rock sample (1) at the center of the two base plates. Step S2: Activate the biaxial rock mechanics testing system and compress the two pressure relay devices to a fully closed state. Step S3: The rock sample (1) is continuously loaded using a quasi-static displacement loading method until a rock burst occurs, while the multi-source information monitoring system continuously records data. Step S4: Analyze the transient process of spontaneous rockburst's millisecond-level static-dynamic state change and summarize the catastrophic mechanism of spontaneous rockburst change.

10. The simulation method according to claim 9, characterized in that, In step S3, the loading speed of the biaxial rock mechanics test system is 0.01 mm / s. When the multi-source information monitoring system detects a high-frequency AE signal and a sudden change in displacement, it is determined that a rock burst has occurred.

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