Fault zone tunneling and grouting integrated rock burst simulation test system and method

Abstract

The invention belongs to the technical field of coal mining simulation tests, and particularly relates to a fault zone tunneling and grouting integrated rock burst simulation test system and method. The test system comprises a triaxial confining pressure loading unit, a modular boundary constraint unit, a data monitoring feedback unit, a roadway tunneling unit and a fault grouting unit. The modularized boundary constraint unit comprises a test cavity which is defined by a first loading plate, a second loading plate, a third loading plate, a fourth loading plate, a first barrier plate and a second barrier plate and is used for accommodating a sample; each of the first loading plate and the second loading plate comprises two segmented plates, and the two segmented plates are connected through an inclined plane; the defect that a traditional test process is split is overcome, integrated continuous simulation from stress loading, fault slippage, tunneling disturbance to grouting reinforcement is achieved, and reliable experimental equipment and theoretical support are provided for deep underground engineering disaster prevention and control.

Description

Technical Field

[0001] This invention belongs to the field of coal mine mining simulation test technology, specifically relating to an integrated rockburst simulation test system and method for tunneling and grouting in fault zones. Background Technology

[0002] Deep coal mining often faces the dual challenges of high ground stress and strong disturbance. When tunnels pass through faults, the surrounding rock is highly susceptible to instability, inducing rockbursts. To effectively control the risk of fault activation and ensure the stability of the surrounding rock, borehole grouting reinforcement technology is widely used in engineering sites for the pre-treatment of fault fracture zones, which can effectively improve the stability of the surrounding rock. Therefore, in-depth research into the spatiotemporal evolution of tunnel excavation disturbance, fault shear slip, and grouting reinforcement effects is of significant engineering importance for guiding safe and efficient mining under complex geological conditions.

[0003] However, existing physical simulation equipment and methods for coal and rock masses still have significant technical limitations in the integrated simulation of tunneling and grouting in fault zones, making it difficult to meet the actual needs of research on the mechanisms of disasters in deep engineering. These limitations are mainly reflected in the following aspects: Existing testing systems are relatively limited in function and lack a comprehensive platform capable of continuously simulating tunnel excavation and borehole grouting processes. Traditional rock mechanics testing machines primarily focus on studying the mechanical loading and failure characteristics of specimens, making it difficult to continuously complete complex processes such as triaxial stress loading, fault shear slip, solid tunnel cutting, and high-pressure borehole grouting within the same setup. This fragmentation of processes prevents the tests from accurately reflecting actual field conditions, resulting in significant discrepancies between indoor simulation results and field engineering practice.

[0004] Therefore, there is an urgent need to develop a rockburst simulation test system and method that integrates triaxial stress loading, adaptive fault slip, solid tunnel excavation, and borehole sealing grouting functions, so as to provide reliable experimental equipment and theoretical support for disaster prevention and control in deep underground engineering. Summary of the Invention

[0005] This invention aims to overcome the limitations of existing physical simulation test equipment for coal and rock masses, and provides an integrated rockburst simulation test system and method for tunneling and grouting in fault zones.

[0006] This invention provides the following technical solution: an integrated rockburst simulation test system for tunneling and grouting in fault zones, comprising a triaxial confining pressure loading unit, a modular boundary constraint unit, a data monitoring and feedback unit, a tunneling unit, and a fault grouting unit; The modular boundary constraint unit includes a test cavity for accommodating the sample, which is formed by a first loading plate, a second loading plate, a third loading plate, a fourth loading plate, a first blocking plate, and a second blocking plate. The first loading plate and the second loading plate serve as the top plate and the bottom plate of the test cavity, the first blocking plate and the third loading plate serve as the left side plate and the right side plate of the test cavity, and the fourth loading plate and the second blocking plate serve as the front panel and the rear panel of the test cavity. The first loading plate and the second loading plate each include two segmented plates, which are connected by an inclined plane; the first blocking plate and the second blocking plate are fixed, and the third loading plate, the fourth loading plate, and the segmented plates in the first loading plate and the second loading plate are each connected to an independent loading mechanism in the triaxial confining pressure loading unit. The first baffle plate has a window connecting the inside and outside of the test chamber. The drill rod of the tunnel excavation unit enters the test chamber through the window to drill the sample; the fault grouting unit grouts the drill hole through the hollow structure of the drill rod. The data monitoring and feedback unit includes a stress strain gauge, a high-speed camera, an acoustic emission sensor, an acoustic emission analyzer, a ring electromagnetic receiving antenna, an electromagnetic signal analyzer, and an infrared thermal imager; it is used to collect stress and strain, acoustic emission, electromagnetic radiation signals, and crack conditions of the sample.

[0007] Furthermore, the triaxial confining pressure loading unit includes a support frame, and the modular boundary constraint unit is located within the support frame; The first blocking plate is fixed to the support frame by a horizontal bearing frame, and the second blocking plate is fixed to the support frame by a lateral bearing frame. The third loading plate, the fourth loading plate, and the segmented plates in the first and second loading plates are each connected to the hydraulic cylinder.

[0008] Furthermore, the first loading plate includes a long segment plate and a short segment plate; a first track is provided on the long segment plate and the short segment plate, and one end of the longitudinally mounted movable hydraulic cylinder connected to the long segment plate and the short segment plate is fixed on the support frame, and the other end slides with the first track through a sliding seat; The second loading plate also includes a long segment plate and a short segment plate, and the long segment plate and the short segment plate of the first loading plate and the second loading plate are staggered.

[0009] Furthermore, the triaxial confining pressure loading unit includes a bracket and a reaction frame. The bracket is connected to the support frame, and the reaction frame is slidably mounted on the second guide rail at the top of the bracket. Limiters are installed on the second guide rail at the front and rear of the reaction frame. The third loading plate is connected to the reaction frame through a transversely moving hydraulic cylinder.

[0010] Furthermore, the fourth loading plate is connected to the support frame via a fixed hydraulic cylinder.

[0011] Furthermore, the tunnel excavation unit includes a mobile trolley, the upper and lower ends of which are connected to the support frame via connecting rods; the mobile trolley is equipped with a lifting platform, on which a drilling rig is installed, and the drill rod is connected to the torque output end of the drilling rig.

[0012] Furthermore, the fault grouting unit includes a pump set, a water injection pipe, and a grouting pipe. The pump set is connected to a water tank and a grout tank respectively through a suction pipe. The water injection pipe and the grouting pipe are located inside the drill rod. The water injection pipe and the grouting pipe can be connected to the water outlet of the pump set and the grout outlet respectively through external pipelines. The drill rod is covered with a bladder. The diameter of the drill bit on the drill rod is larger than the outer diameter of the drill rod. When the bladder contracts, it is contained within the diameter difference between the drill bit and the drill rod. The water injection pipe is connected to the bladder through an opening on the drill rod. The area between the two bladders is the grouting section. The grouting pipe is connected to the grouting section through an opening on the drill rod.

[0013] Furthermore, acoustic emission sensors are distributed on the sample surface, and a ring electromagnetic receiving antenna is positioned at the window of the first blocking plate. The drill rod passes through the ring electromagnetic receiving antenna and drills into the sample.

[0014] Furthermore, the first loading plate and the second loading plate are in contact with the third loading plate through a sliding nested telescopic plate. A spring connects the telescopic plate to the first loading plate or the second loading plate. As the third loading plate moves, the telescopic plate slides forward and backward. A loading gap is reserved between the first loading plate, the second loading plate, and the fourth loading plate.

[0015] A method for simulating rockburst through tunneling and grouting in fault zones involves the following steps using an integrated rockburst simulation system: S1: Prepare a sample, place acoustic emission sensors on the sample surface, and install a ring electromagnetic receiving antenna at the window of the first blocking plate. S2: Load the specimen into the test chamber of the modular boundary constraint unit; S3: The loading mechanism of the triaxial confining pressure loading unit is activated to push the first loading plate, the second loading plate, the third loading plate and the fourth loading plate to press the sample and construct a deep formation stress environment; the test data is collected in real time through the data monitoring and feedback unit; S4: Control the longitudinally placed movable hydraulic cylinder to apply differential load to the first loading plate and the second loading plate, causing the long segment plate and one short segment plate in the first loading plate and the second loading plate to shift, compress the sample to cause relative shear slip, until the preset fault slip is induced. S5: Drilling of the tunnel excavation unit, drilling holes in the sample under stress to simulate tunnel excavation in a fault zone; S6: After drilling is completed, keep the load of each loading mechanism of the triaxial confining pressure loading unit constant; connect the water injection pipe and grouting pipe in the drill rod to the pump group for sealing and grouting. S7: After the grout in the borehole has been pressurized for a period of time, the fault grouting unit first stops grouting, then releases the hole seal and the drill rod is withdrawn from the borehole; finally, the loads of each loading mechanism of the triaxial confining pressure loading unit are removed.

[0016] Compared with the prior art, the advantages of the present invention are: Existing equipment has limited functionality and cannot continuously complete complex processes from loading, sliding, tunneling to grouting on a single platform. This invention designs a drill rod with internal independent water and grouting pipelines, along with a matching sealing bag structure. In the simulation of tunnel excavation impact damage induced by fault slippage, in-situ sealing and high-pressure grouting reinforcement can be performed directly using the drill rod without disassembling the drilling tools. This overcomes the fragmented nature of traditional experimental procedures and realistically reflects the spatiotemporal evolution of fault failure and grouting reinforcement.

[0017] To address the limitations of existing equipment structures, this invention designs the first and second loading plates, which form the top and bottom plates of the test chamber, as two segmented structures. The two segmented plates are connected by an inclined plane, and each segment is connected to an independent longitudinally mounted movable hydraulic cylinder. The longitudinally mounted movable hydraulic cylinder applies different thrusts to the segmented plates of the first and second loading plates, causing the specimen between the first and second loading plates to undergo vertical displacement. Under the action of the inclined plane between the segmented plates, the specimen simultaneously undergoes transverse tearing, simulating fault shear slip.

[0018] To address the sensitivity of fault slip simulation to boundary conditions, the third loading plate, fourth loading plate, first blocking plate, and second blocking plate in this invention are fitted with rollers parallel to the slip direction of the sample on their contact surfaces. This rolling contact method reduces the boundary friction resistance of the sample, effectively eliminating the interference of boundary effects on the experimental results, thereby improving the reliability of the research results on fault activation patterns and rockburst evolution mechanisms. Attached Figure Description

[0019] Figure 1 A schematic diagram of an integrated rockburst simulation test system for tunneling and grouting in fault zones; Figure 2 This is a schematic diagram of the fourth loading plate and the second blocking plate; Figure 3 This is a schematic diagram simulating the fault zone displacement of the sample. Figure 4 This is a schematic diagram of a simulated tunnel excavation in a fault zone of a sample. Figure 5 This is a schematic diagram of grouting. Figure 6 This is a magnified view of the grouting area; Figure 7 This is a schematic diagram showing the contact positions of the first loading plate, the second loading plate, and the third loading plate.

[0020] In the diagram: 1-First loading plate; 1.1-Long segmented plate; 1.2-Short segmented plate; 1.3-First track; 1.4-Longitudinal movable hydraulic cylinder; 1.5-Telescopic plate; 1.6-Spring; 2-Second loading plate; 3-Third loading plate; 4-Fourth loading plate; 5-First blocking plate; 5.1-Window; 6-Second blocking plate; 7-Drill rod; 8-Acoustic emission sensor; 9-Acoustic emission analyzer; 10-Loop electromagnetic receiving antenna; 11-Electromagnetic signal analyzer; 12-Supporting frame ; 13-Horizontal bearing frame; 14-Lateral bearing frame; 15-Support; 15.1-Second guide rail; 15.2-Limiter; 16-Reaction frame; 17-Horizontal moving hydraulic cylinder; 18-Fixed hydraulic cylinder; 19-Mobile trolley; 20-Connecting rod; 21-Lifting platform; 22-Drilling rig; 23-Pump set; 24-Water injection pipe; 25-Grouting pipe; 26-Water bucket; 27-Grouting tank; 28-Bag; 29-Hydraulic pump station; 30-Multi-channel monitoring and control host; 31-Grouting body. Detailed Implementation

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

[0022] Example 1 like Figure 1 , Figure 2 As shown: A fault zone tunneling and grouting integrated rockburst simulation test system includes a triaxial confining pressure loading unit, a modular boundary constraint unit, a data monitoring and feedback unit, a tunneling unit, and a fault grouting unit; The modular boundary constraint unit includes a test cavity for accommodating the sample, which is formed by a first loading plate 1, a second loading plate 2, a third loading plate 3, a fourth loading plate 4, a first blocking plate 5, and a second blocking plate 6. The test cavity is a cuboid cavity. The first loading plate 1 and the second loading plate 2 serve as the top and bottom plates of the test cavity, the first blocking plate 5 and the third loading plate 3 serve as the left and right side plates of the test cavity, and the fourth loading plate 4 and the second blocking plate 6 serve as the front and rear panels of the test cavity.

[0023] The first loading plate 1 and the second loading plate 2 each include two segmented plates connected by an inclined plane. The angle of the inclined plane between the segmented plates of the first loading plate 1 and the second loading plate 2 is adapted to the preset tilt angle of the fault slip surface. The first blocking plate 5 and the second blocking plate 6 are fixed. The third loading plate 3, the fourth loading plate 4, and the segmented plates in the first loading plate 1 and the second loading plate 2 are each connected to an independent loading mechanism in the triaxial confining pressure loading unit. The loading mechanism is a hydraulic cylinder, which is connected to the hydraulic pump station 29. The multi-channel measurement and control host 30 is connected to the hydraulic pump station 29 to control the action of each hydraulic cylinder. When the segmented plates of the first loading plate 1 and the second loading plate 2 simultaneously compress the specimen, the specimen undergoes vertical displacement, and under the action of the inclined plane between the segmented plates, the specimen simultaneously undergoes transverse tearing, simulating fault shear slip.

[0024] The first baffle plate 5 has a window 5.1 that connects the inside and outside of the test chamber. The window 5.1 is located in the middle of the height range of the test chamber. The drill rod 7 of the tunnel excavation unit enters the test chamber through the window 5.1 to drill the sample. The fault grouting unit grouts the drill hole through the hollow structure of the drill rod 7.

[0025] The test specimen is a similar simulated specimen; rollers parallel to the sliding direction of the specimen are embedded on the surfaces of the third loading plate 3, the fourth loading plate 4, the first blocking plate 5, and the second blocking plate 6 that are in contact with the specimen. The boundary friction resistance of the specimen is reduced by the rolling contact method, effectively eliminating the interference of boundary effects on the test results.

[0026] The triaxial confining pressure loading unit includes a support frame 12, and a modular boundary constraint unit is located inside the support frame 12; the first blocking plate 5 is fixed to the support frame 12 by a horizontal bearing frame 13, and the second blocking plate 6 is fixed to the support frame 12 by a lateral bearing frame 14; the third loading plate 3, the fourth loading plate 4, and the segmented plates in the first loading plate 1 and the second loading plate 2 are each connected to a hydraulic cylinder.

[0027] The first loading plate 1 includes a long segment plate 1.1 and a short segment plate 1.2; a first track 1.3 is provided on the long segment plate 1.1 and the short segment plate 1.2; one end of the longitudinally placed movable hydraulic cylinder 1.4 connected to the long segment plate 1.1 and the short segment plate 1.2 is fixed on the support frame 12, and the other end is slidably engaged with the first track 1.3 through a sliding seat; when the long segment plate 1.1 or the short segment plate 1.2 is laterally offset due to the slope of the two, it can slide relative to the longitudinally placed movable hydraulic cylinder 1.4.

[0028] The second loading plate 2 also includes a long segment plate 1.1 and a short segment plate 1.2. The long segment plate 1.1 and the short segment plate 1.2 of the first loading plate 1 and the second loading plate 2 are staggered, that is, the short segment plate 1.2 of the second loading plate 2 is below the long segment plate 1.1 of the first loading plate 1, and the long segment plate 1.1 of the second loading plate 2 is below the short segment plate 1.2 of the first loading plate 1.

[0029] The long segmented plate 1.1 and short segmented plate 1.2 constituting the first loading plate 1 include several pairs with different contact surface slopes. Similarly, the long segmented plate 1.1 and short segmented plate 1.2 constituting the second loading plate 2 also include several pairs with different contact surface slopes. The fault dip angle can be adjusted by replacing the long segmented plate 1.1 and short segmented plate 1.2 with different slopes in the first loading plate 1 and the long segmented plate 1.1 and short segmented plate 1.2 constituting the second loading plate 2. The principle for replacement is that the slopes of the long segmented plate 1.1 and short segmented plate 1.2 constituting the first loading plate 1 are the same as the slopes of the long segmented plate 1.1 and short segmented plate 1.2 constituting the second loading plate 2.

[0030] like Figure 7 As shown: the first loading plate 1 and the second loading plate 2 are in contact with the third loading plate 3 through a sliding nested telescopic plate 1.5. A spring 1.6 is connected between the telescopic plate 1.5 and the first loading plate 1 or the second loading plate 2. The telescopic plate 1.5 slides forward and backward as the third loading plate 3 moves. A loading gap is reserved between the first loading plate 1 and the second loading plate 2 and the fourth loading plate 4. The fourth loading plate 4 will not collide with the first loading plate 1 and the second loading plate 2 when clamping the sample.

[0031] The triaxial confining pressure loading unit includes a bracket 15 and a reaction frame 16. The bracket 15 is connected to the support frame 12. The reaction frame 16 is slidably mounted on the second guide rail 15.1 on the top of the bracket 15. Limiters 15.2 are installed on the second guide rail 15.1 at the front and rear of the reaction frame 16. The third loading plate 3 is connected to the reaction frame 16 through a transverse moving hydraulic cylinder 17. When the reaction frame 16 moves to the rightmost side of the bracket 15 with the transverse moving hydraulic cylinder 17 and the third loading plate 3, the sample is unloaded (the bracket 15 shown in the figure is a shortened version).

[0032] The fourth loading plate 4 is connected to the support frame 12 by a fixed hydraulic cylinder 18.

[0033] The tunnel excavation unit includes a mobile trolley 19. The upper and lower ends of the mobile trolley 19 are connected to the support frame 12 by a connecting rod 20. The connecting rod 20 connects the mobile trolley 19 and the support frame 12 to prevent the mobile trolley 19 from sliding when the drill rod 7 is drilling. The mobile trolley 19 is equipped with a lifting platform 21, and a drilling rig 22 is installed on the lifting platform 21. The drill rod 7 is connected to the torque output end of the drilling rig 22.

[0034] like Figure 1 , Figure 5 , Figure 6 As shown: The fault grouting unit includes a pump set 23, a water injection pipe 24, and a grouting pipe 25. The pump set 23 is connected to a water tank 26 and a grout tank 27 via suction pipes. The water injection pipe 24 and the grouting pipe 25 are located inside the drill rod 7. The water injection pipe 24 and the grouting pipe 25 can be connected to the water outlet of the pump set 23 and the grout outlet via external pipelines, respectively. The drill rod 7 is covered with a bladder 28, which is a hydraulically expandable structure. Its internal cavity is connected to the water injection pipe 24, and expansion through water pressure achieves connection with the borehole. The wall is tightly sealed, and the bag 28 has elastic retraction characteristics. When the water inside is drained, the bag 28 contracts. The diameter of the drill bit on the drill rod 7 is larger than the outer diameter of the drill rod 7. When the bag 28 contracts, it is contained within the diameter difference between the drill bit and the drill rod 7, preventing the bag 28 from being damaged by friction with the borehole wall during the drilling process. The water injection pipe 24 is connected to the bag 28 through the opening on the drill rod 7. The area between the two bags 28 is the grouting section. The grouting pipe 25 is connected to the grouting section through the opening on the drill rod 7.

[0035] The data monitoring and feedback unit includes a stress-strain gauge, a high-speed camera, acoustic emission sensors 8, an acoustic emission analyzer 9, a ring electromagnetic receiving antenna 10, an electromagnetic signal analyzer 11, and an infrared thermal imager. It is used to collect stress-strain, acoustic emission, electromagnetic radiation signals, and crack conditions of the sample. The high-speed camera observes the internal crack evolution of the sample through a window 5.1 on the first blocking plate 5. Acoustic emission sensors 8 are distributed on the sample surface and are connected to the acoustic emission analyzer 9. The ring electromagnetic receiving antenna 10 is positioned at the window 5.1 of the first blocking plate 5 and is connected to the electromagnetic signal analyzer 11. The drill rod 7 passes through the ring electromagnetic receiving antenna 10 and drills into the sample.

[0036] Acoustic emission monitoring technology, as a core means of capturing microscopic precursors of fault activation, is based on the physical principle of monitoring fault-induced rockbursts, which is the transient release mechanism of elastic waves during the failure process of coal and rock media. During the application of non-uniform shear loads to the sample, rock particles inside and around the fault zone first undergo compaction and elastic deformation. Each initiation, propagation, or closure of a microcrack releases accumulated elastic strain energy instantaneously in the form of stress waves. Acoustic emission sensors 8, arranged on the sample surface, can pick up these high-frequency elastic wave signals in real time. During the experiment, the system not only records conventional parameters such as ring count and energy rate, but also focuses on the frequency domain characteristics and spatial distribution of the signals: during the fault incubation period, the signals are mostly low-amplitude frictional noise; when the shear force applied by the first loading plate 1 and the second loading plate 2 causes the fault to enter a "critical instability state," the acoustic emission event rate spikes exponentially, and the b-value (ratio of large to small fracture events) decreases significantly, indicating that microfractures are rapidly evolving into large-scale fault penetration. Through a multi-channel time difference positioning algorithm, the formation trajectory of the fault activation surface and the direction of fracture propagation can be accurately depicted in the three-dimensional space of the test chamber, thereby verifying the quantitative relationship between the fault dip angle and the rockburst triggering threshold set by the simulation test system of this embodiment at the microscopic level.

[0037] An electromagnetic radiation monitoring system, consisting of a loop electromagnetic receiving antenna 10 and an electromagnetic signal analyzer 11, is designed to detect abrupt changes in stress concentration zones within fault zones using non-contact methods. Its physical principle stems from the piezoelectric effect of coal and rock mass and the charge separation effect at crack tips. Piezoelectric minerals such as quartz, widely present in the samples, generate polarized electric fields under the strong stress environment applied by the triaxial confining pressure loading unit. More importantly, when the fault is about to slip, the rapid crack propagation leads to the breaking of chemical bonds at the crack tip, electron escape, and violent separation and oscillation of positive and negative charge centers, thereby radiating pulsed electromagnetic wave signals outwards. The loop electromagnetic receiving antenna 10 is positioned near window 5.1, oriented towards the fault core region. Compared to acoustic emission signals, electromagnetic radiation signals are more sensitive to abrupt changes in stress gradients and their propagation is not limited by acoustic contact conditions with the medium. During the "quiet period" before the impact of fault displacement, the intensity of electromagnetic radiation often shows a "pulse-like surge" or "high-energy oscillation" before the macroscopic damage. This signal characteristic serves as an early warning indicator of fault activation, which can effectively compensate for the blind spots of contact monitoring and reproduce the abnormal response law of electromagnetic field during the incubation of rockburst.

[0038] Infrared thermal imaging technology is used to monitor the temperature field evolution throughout the entire process of rockburst in real time. Its core principle is based on the thermoelastic effect of rock mechanics and the frictional heat effect during fault slip. In the initial stage of the experiment, the sample undergoes elastic deformation under the compression of the triaxial confining pressure loading unit, and the volume change causes slight thermoelastic fluctuations in the sample surface temperature. When the first loading plate 1 and the second loading plate 2 successfully induce macroscopic fault slippage, the intense mechanical friction between the hanging wall and footwall instantly converts the accumulated elastic potential energy into heat energy, causing a sharp rise in temperature at the fault slip surface and fracture tip. Through window 5.1, the infrared thermal imager can capture and generate a high-resolution temperature field cloud map in real time. By tracking the occurrence time, distribution pattern, and highest temperature rise point of abnormal high-temperature bands in the thermal image, the initiation location, slip direction, and friction intensity of the fault can be intuitively reflected, providing a visualized thermodynamic basis for the occurrence of fault-slip rockbursts.

[0039] High-speed cameras are not only used to record experimental phenomena, but also to perform quantitative analysis of the full-field deformation and macroscopic dynamic response of fault displacement using digital image correlation (DIC). The principle involves creating an artificial speckle field on the sample surface, continuously acquiring high-frame-rate images through a 5.1-inch window using a camera, and tracking the displacement vectors of the speckles before and after deformation using an algorithm to calculate the full-field displacement field, strain field, and shear band distribution. This monitoring method has dual functions: first, during tunnel excavation, it monitors the convergent deformation and non-uniform strain concentration zones of the surrounding rock in real time, capturing the "trigger point" of rockburst; second, at the moment of impact instability, it utilizes its high spatiotemporal resolution to capture the ejection velocity, ejection distance, and crater morphology of the surrounding rock fragments.

[0040] Example 2 A method for simulating rockburst through tunneling and grouting in fault zones, comprising the following steps using an integrated rockburst simulation system for tunneling and grouting in fault zones as described in Example 1: S1: Prepare a sample, place an acoustic emission sensor 8 on the surface of the sample, and install a ring electromagnetic receiving antenna 10 at the window 5.1 of the first blocking plate 5. S2: Load the specimen into the test chamber of the modular boundary constraint unit; S3: The loading mechanism of the triaxial confining pressure loading unit is activated to push the first loading plate 1, the second loading plate 2, the third loading plate 3 and the fourth loading plate 4 to compress the sample and construct a deep formation stress environment; the test data is collected in real time through the data monitoring and feedback unit; S4: As Figure 3As shown, the longitudinally positioned movable hydraulic cylinder 1.4 is controlled to apply a differential load to the first loading plate 1 and the second loading plate 2, causing the long segment plate 1.1 and the short segment plate 1.2 in the first loading plate 1 and the second loading plate 2 to shift and compress the sample to cause relative shear slip until the preset fault slip is induced. S5: As Figure 4 As shown, the drill rod 7 of the tunnel excavation unit drills holes in the sample under stress to simulate tunnel excavation in a fault zone. S6: As Figure 5 , Figure 6 As shown, after drilling is completed by drill rod 7, the load of each loading mechanism of the triaxial confining pressure loading unit is kept constant; the water injection pipe 24 and grouting pipe 25 inside drill rod 7 are connected to pump group 23 for sealing and grouting. S7: After the grout in the borehole has been pressurized for a period of time, the fault grouting unit first stops grouting, then releases the hole seal, and the drill rod 7 is withdrawn from the borehole; finally, the loads of each loading mechanism of the triaxial confining pressure loading unit are removed.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fault zone tunneling and grouting integrated rockburst simulation test system, characterized in that: It includes a triaxial confining pressure loading unit, a modular boundary constraint unit, a data monitoring and feedback unit, a tunnel excavation unit, and a fault grouting unit; The modular boundary constraint unit includes a test cavity for accommodating the test specimen, which is formed by a first loading plate (1), a second loading plate (2), a third loading plate (3), a fourth loading plate (4), a first blocking plate (5), and a second blocking plate (6); the first loading plate (1) and the second loading plate (2) serve as the top and bottom plates of the test cavity, the first blocking plate (5) and the third loading plate (3) serve as the left and right side plates of the test cavity, and the fourth loading plate (4) and the second blocking plate (6) serve as the front and rear panels of the test cavity; The first loading plate (1) and the second loading plate (2) each include two segmented plates, which are connected by an inclined plane; the first blocking plate (5) and the second blocking plate (6) are fixed, and the third loading plate (3), the fourth loading plate (4) and the segmented plates in the first loading plate (1) and the second loading plate (2) are each connected to an independent loading mechanism in the triaxial confining pressure loading unit. The first baffle plate (5) has a window (5.1) connecting the inside and outside of the test chamber. The drill rod (7) of the tunnel excavation unit enters the test chamber through the window (5.1) to drill the sample. The fault grouting unit grouts the drill hole through the hollow structure of the drill rod (7). The data monitoring and feedback unit includes a stress strain gauge, a high-speed camera, an acoustic emission sensor (8), an acoustic emission analyzer (9), a ring electromagnetic receiving antenna (10), an electromagnetic signal analyzer (11), and an infrared thermal imager; used to collect stress strain, acoustic emission, electromagnetic radiation signals, and crack conditions of the sample.

2. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 1, characterized in that: The triaxial confining pressure loading unit includes a support frame (12), and the modular boundary constraint unit is located within the support frame (12); The first blocking plate (5) is fixed to the support frame (12) by the horizontal bearing frame (13), and the second blocking plate (6) is fixed to the support frame (12) by the lateral bearing frame (14); The third loading plate (3), the fourth loading plate (4), and the segmented plates in the first loading plate (1) and the second loading plate (2) are each connected to the hydraulic cylinder.

3. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 2, characterized in that: The first loading plate (1) includes a long segment plate (1.1) and a short segment plate (1.2); a first track (1.3) is provided on the long segment plate (1.1) and the short segment plate (1.2); one end of a longitudinally mounted movable hydraulic cylinder (1.4) connected to the long segment plate (1.1) and the short segment plate (1.2) is fixed on the support frame (12), and the other end slides with the first track (1.3) through a sliding seat; The second loading plate (2) also includes a long segment plate (1.1) and a short segment plate (1.2), and the long segment plate (1.1) and the short segment plate (1.2) of the first loading plate (1) and the second loading plate (2) are staggered.

4. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 2, characterized in that: The triaxial confining pressure loading unit includes a bracket (15) and a reaction frame (16). The bracket (15) is connected to the support frame (12). The reaction frame (16) is slidably mounted on the second guide rail (15.1) at the top of the bracket (15). Limiters (15.2) are installed on the second guide rail (15.1) at the front and rear of the reaction frame (16). The third loading plate (3) is connected to the reaction frame (16) through a horizontally moving hydraulic cylinder (17).

5. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 2, characterized in that: The fourth loading plate (4) is connected to the support frame (12) by a fixed hydraulic cylinder (18).

6. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 3, characterized in that: The tunnel excavation unit includes a mobile trolley (19), the upper and lower ends of which are connected to the support frame (12) via connecting rods (20); a lifting platform (21) is mounted on the mobile trolley (19), a drilling rig (22) is installed on the lifting platform (21), and the drill rod (7) is connected to the torque output end of the drilling rig (22).

7. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 6, characterized in that: The fault grouting unit includes a pump set (23), a water injection pipe (24), and a grouting pipe (25). The pump set (23) is connected to a water tank (26) and a slurry tank (27) through a suction pipe. The water injection pipe (24) and the grouting pipe (25) are located inside the drill rod (7). The water injection pipe (24) and the grouting pipe (25) can be connected to the water outlet and the slurry outlet of the pump set (23) through external pipelines. The drill rod (7) is covered with a bag (28). The diameter of the drill bit on the drill rod (7) is larger than the outer diameter of the drill rod (7). When the bag (28) contracts, it is contained within the diameter difference between the drill bit and the drill rod (7). The water injection pipe (24) is connected to the bag (28) through an opening on the drill rod (7). The area between the two bags (28) is the grouting section. The grouting pipe (25) is connected to the grouting section through an opening on the drill rod (7).

8. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 1, characterized in that: The acoustic emission sensor (8) is distributed on the surface of the sample, the ring electromagnetic receiving antenna (10) is arranged at the window (5.1) of the first blocking plate (5), and the drill rod (7) passes through the ring electromagnetic receiving antenna (10) and drills into the sample.

9. The integrated rockburst simulation test system for tunneling and grouting in fault zones according to claim 2, characterized in that: The first loading plate (1) and the second loading plate (2) are in contact with the third loading plate (3) through a sliding nested telescopic plate (1.5). A spring (1.6) is connected between the telescopic plate (1.5) and the first loading plate (1) or the second loading plate (2). The telescopic plate (1.5) moves with the third loading plate (3) and slides forward and backward. A loading gap is reserved between the first loading plate (1), the second loading plate (2), and the fourth loading plate (4).

10. A method for simulating rockburst through tunneling and grouting in fault zones, comprising the following steps using the integrated rockburst simulation system for tunneling and grouting in fault zones as described in claim 7: S1: Prepare a sample, place an acoustic emission sensor (8) on the surface of the sample, and install a ring electromagnetic receiving antenna (10) at the window (5.1) of the first blocking plate (5). S2: Load the specimen into the test chamber of the modular boundary constraint unit; S3: Start the loading mechanism of the triaxial confining pressure loading unit to push the first loading plate (1), the second loading plate (2), the third loading plate (3) and the fourth loading plate (4) to press the sample and construct the deep formation stress environment; collect test data in real time through the data monitoring feedback unit; S4: Control the longitudinally placed movable hydraulic cylinder (1.4) to apply differential load to the first loading plate (1) and the second loading plate (2), so that the long segment plate (1.1) and a short segment plate (1.2) in the first loading plate (1) and the second loading plate (2) are misaligned, and the sample is squeezed to cause relative shear slip until the preset fault slip is induced. S5: Drilling of the drill rod (7) of the tunnel excavation unit, drilling of the sample under stress, simulating tunnel excavation in the fault zone; S6: After drilling is completed, keep the load of each loading mechanism of the triaxial confining pressure loading unit constant; connect the water injection pipe (24) and grouting pipe (25) in the drill rod (7) to the pump group (23) for sealing and grouting; S7: After the grout in the borehole has been pressurized for a period of time, the fault grouting unit stops grouting first, then releases the hole seal and the drill rod (7) is withdrawn from the borehole; finally, the loads of each loading mechanism of the triaxial confining pressure loading unit are removed.

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