Test device and method for multidirectional simulation control of roadway confining pressure

Abstract

The invention discloses a test device and method for multidirectional simulation control of roadway confining pressure, and relates to the technical field of rock mechanics and mining engineering.The test device comprises a pressurization assembly, a model assembly and a monitoring assembly, and the pressurization assembly comprises a pressurization frame, a force transmission frame, multiple sets of pressurization pieces and multiple sets of force transmission pieces; the model assembly comprises a model body and a filling body; a simulation roadway is formed in the model body; calibration speckle spots are arranged on the surface of the filling body; the monitoring assembly comprises a plurality of groups of pressure sensors, a plurality of groups of strain sensors and a monitor; a plurality of groups of hydraulic oil cylinders are arranged to pressurize the model, so that the loading capacity which can be independently controlled in multiple directions is realized, loads which are from different directions and are adjustable in size are flexibly and accurately applied, the complex surrounding rock pressure state actually borne by a roadway is highly and vividly simulated, the hydraulic oil cylinders are uniformly arranged along the circumference, the flexible combination of the loading directions is realized, and the loading efficiency is improved. Any asymmetric load can be accurately simulated, the external load can be uniformly transmitted to the model through the multiple sets of force transmission pieces, and a stress concentration blind area is eliminated.

Description

Technical Field

[0001] This invention relates to the fields of rock mechanics and mining engineering technology, specifically to a test device and method for multi-directional simulation control of roadway confining pressure. Background Technology

[0002] As the core passageway for mine production, the stability of roadways is crucial. However, frequent occurrences of large deformations and even collapses in roadways seriously threaten the normal production order and the safety of personnel and equipment. In-depth analysis shows that the surrounding rock pressure is the main factor inducing roadway deformation and even failure. Especially in roadways with weak or ineffective support, the surrounding rock pressure can easily lead to local stress concentration, causing accidents such as the sudden fall of individual rock blocks, posing a major safety hazard. In recent years, the combined effect of abnormally increased surrounding rock pressure and insufficient bearing capacity of the support structure has triggered several serious accidents, causing heavy casualties and huge economic losses. The decisive influence of surrounding rock pressure on roadway stability undeniably highlights the extreme importance of scientific and reasonable roadway support design for ensuring safe mine production and the safety of personnel. Therefore, in order to prevent such accidents from the source and ensure the long-term stability of the mine, it is urgent to predict the deformation response under actual confining pressure through accurate experimental simulations in the early stages of roadway construction and maintenance, thereby providing a solid scientific basis for the optimized design of support schemes.

[0003] Currently widely used tunnel confining pressure simulation test devices have significant limitations: their loading methods are mostly unidirectional or bidirectional, meaning they can only simulate vertical loads (such as roof pressure) or loads with added lateral loads (such as sidewall pressure). This simplified model cannot accurately reproduce the complex three-dimensional stress environment of actual tunnels (i.e., multidirectional, non-uniform pressure from the roof, floor, and sidewalls), leading to discrepancies between simulation results and actual engineering conditions, and failing to provide sufficiently reliable guidance for support design. Summary of the Invention

[0004] The main objective of this invention is to provide a test device and method for multi-directional simulation control of roadway confining pressure, which solves the problem that existing roadway confining pressure simulation test devices are unable to accurately reproduce the complex three-dimensional stress environment of actual roadways.

[0005] To achieve the above objectives, the present invention provides a test apparatus for multi-directional simulation control of roadway confining pressure, comprising: The pressurization assembly includes a pressurization frame and a force transmission frame disposed within the pressurization frame; multiple sets of pressurization components are equidistantly arranged on the outside of the pressurization frame; multiple sets of force transmission components are circumferentially arranged within the force transmission frame; the force transmission components are arranged in multiple layers from the inside to the outside along the radial direction of the force transmission frame, with interlayer gaps formed between adjacent force transmission components and in a vacuum state. The model assembly includes a model body located at the center of the force transmission frame and a filler body located between the model body and the force transmission frame; the interior of the model body is hollow to form a simulated tunnel; the surface of the filler body is provided with calibration speckles. The monitoring component includes multiple sets of pressure sensors disposed within the infill body, multiple sets of strain sensors disposed on the force transmission component, and a monitor disposed above the infill body; the pressure sensors are distributed around the perimeter of the model body; the strain sensors are disposed adjacent to the infill body; the pressure component, under the action of external force, transmits the force evenly to the infill body through the force transmission component, and monitors the force through the pressure sensors and strain sensors and transmits the values ​​to the external control system; the monitor is used to monitor the changes in the calibrated speckle stress field on the surface of the infill body and transmits the data to the external control system.

[0006] As a further improvement of the present invention, the pressure frame is a ring formed by welding steel plates and steel beams; the outer wall of the pressure frame is provided with pressure holes; and a force transmission rod is installed in the pressure holes.

[0007] As a further improvement of the present invention, the pressurizing component includes a hydraulic cylinder; the hydraulic cylinder abuts against the force transmission rod.

[0008] As a further improvement of the present invention, the hydraulic cylinders are evenly arranged radially along the pressure frame; the force transmission rods are arranged in a group at 11.25° intervals along the circumference of the pressure frame; and the hydraulic cylinders are arranged corresponding to the force transmission rods.

[0009] As a further improvement of the present invention, the force transmission frame is hollow and closed to form a vacuum force transmission cavity; the shape of the force transmission frame is consistent with the shape of the pressure frame, the outer wall of the force transmission frame is closely attached to the inner wall of the pressure frame, and a vacuum valve communicating with the force transmission cavity is provided on the force transmission frame.

[0010] As a further improvement of the present invention, the force transmission component includes a force transmission steel block; the force transmission steel block is installed in the vacuum force transmission cavity, and the force transmission steel block located on the outer layer blocks the gap between the force transmission steel blocks located on the inner layer.

[0011] As a further improvement of the present invention, the interlayer gap between the adjacent force-transmitting steel blocks increases sequentially from the inside to the outside.

[0012] As a further improvement of the present invention, the model body includes a model partition; the model partition is located at the center of the force transmission frame; the filler is filled between the model partition and the force transmission frame and the upper end face of the filler is flush with the upper end face of the force transmission frame.

[0013] As a further improvement of the invention, it also includes a support bracket; the support bracket is located above the pressure frame; the monitor includes a high-definition camera mounted on the support bracket.

[0014] The beneficial effects of this invention are reflected in: By setting up multiple sets of hydraulic cylinders to pressurize the model, multi-directional and independently controllable loading capabilities are achieved. Loads from different directions and with adjustable magnitudes can be applied flexibly and accurately, thereby highly realistically simulating the complex surrounding rock pressure state actually borne by the tunnel. The hydraulic cylinders are evenly arranged along the circumference, which can realize flexible combination of loading directions and accurately simulate any asymmetric load. By setting up multiple sets of force transmission components, external loads can be evenly transferred to the model, eliminating stress concentration blind spots, achieving continuous coverage in the full circumference, and avoiding local stress distortion. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the experimental device for multi-directional simulation control of roadway confining pressure according to the present invention; Figure 2 This is a schematic diagram of the strain sensor installation structure of a test device for multi-directional simulation control of roadway confining pressure according to the present invention; Figure 3 This is a schematic diagram of the internal structure of the force transmission component of the test device for multi-directional simulation control of roadway confining pressure according to the present invention; Figure 4 This is a schematic diagram of the support structure of the test device for multi-directional simulation control of roadway confining pressure according to the present invention; Figure 5 This is a schematic diagram of the connection structure between the experimental device for multi-directional simulation control of roadway confining pressure according to the present invention and a PC computer; Figure 6 This is a loading equivalent diagram of an experimental device for multi-directional simulation control of roadway confining pressure according to the present invention; Explanation of reference numerals in the attached figures: 1. Pressure frame; 2. Force transmission frame; 3. Pressure component; 301. Hydraulic cylinder; 302. Oil storage tank; 303. Hydraulic regulating valve; 304. Servo motor; 305. High-pressure oil pipe; 4. Force transmission component; 5. Interlayer gap; 6. Model body; 601. Model partition; 7. Filler; 8. Simulated tunnel; 9. Calibration speckle; 10. Pressure sensor; 11. Strain sensor; 12. Monitor; 13. Worktable; 14. Bottom partition; 15. Pressure hole; 16. Force transmission rod; 17. Vacuum force transmission chamber; 18. Vacuum valve; 19. Support bracket; 20. Signal amplifier; 21. Signal converter; 22. PC computer. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are merely some, not all, of the embodiments of this invention. Unless otherwise specified, the embodiments and features described in this application can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0017] See Figure 1 The present invention provides a test device for multi-directional simulation control of roadway confining pressure, comprising a pressurization component, a model component, and a monitoring component.

[0018] The pressurization assembly includes a pressurization frame 1 and a force transmission frame 2 disposed within the pressurization frame 1. Multiple sets of pressurization components 3 are equidistantly arranged outside the pressurization frame 1. Multiple sets of force transmission components 4 are circumferentially arranged inside the force transmission frame 2. Multiple layers of force transmission components 4 are arranged radially from the inside to the outside of the force transmission frame 2, with interlayer gaps 5 between adjacent force transmission components 4, which are in a vacuum state. The model assembly includes a model body 6 disposed at the center of the force transmission frame 2 and a filler 7 disposed between the model body 6 and the force transmission frame 2. The model body 6 is hollow, forming a simulated tunnel 8. The surface of the filler 7 is provided with calibration speckles 9. A monitoring group... The system includes multiple sets of pressure sensors 10 disposed within the filler 7, multiple sets of strain sensors 11 disposed on the force transmission component 4, and a monitor 12 disposed above the filler 7. The pressure sensors 10 are distributed around the model body 6, and the strain sensors 11 are disposed near the filler 7. Under the action of external force, the pressurizing component 3 transmits the force evenly to the filler 7 through the force transmission component 4. The pressure sensors 10 and strain sensors 11 monitor the force and transmit the values ​​to the external control system. The monitor 12 is used to monitor the stress field changes of the calibrated speckle 9 on the surface of the filler 7 and transmit the data to the external control system.

[0019] To address the inherent limitations of single- and bi-directional loading devices, this invention develops a novel simulation testing device. The core advantage of this device lies in its ability to achieve multi-directional, independently controllable loading capabilities and the development of a force transmission system suitable for circumferential loading. By arranging multiple high-precision hydraulic cylinders 301 around the tunnel model, loads from different directions and of adjustable magnitude can be applied flexibly and accurately, thereby highly realistically simulating the complex surrounding rock pressure conditions actually experienced by the tunnel 8. The hydraulic cylinders 301 are evenly arranged along the circumference, allowing for flexible combinations of loading directions, accurately simulating arbitrary asymmetric loads, eliminating stress concentration blind spots, achieving continuous circumferential coverage, and avoiding localized stress distortion.

[0020] In this embodiment, see Figure 1 , 4The entire experimental apparatus is placed stably on a sturdy workbench 13 to ensure that it is in a horizontal position, so as to avoid deformation of the model or uneven stress due to tilting of the apparatus in subsequent operations. A pre-prepared bottom partition 14 is laid at the bottom of the apparatus. The function of this bottom partition 14 is to provide an initial support surface and facilitate demolding of the model in the future.

[0021] In this embodiment, the pressure frame 1 is a ring made of thick steel plate and steel beam welded together. The thickness of the pressure frame 1 is 70mm-90mm, preferably 80mm. The outer wall of the pressure frame 1 is provided with a pressure hole 15, and a force transmission rod 16 is installed in the pressure hole 15.

[0022] In this embodiment, see Figure 1 The pressurizing component 3 adopts a hydraulic loading system, including a hydraulic cylinder 301, an oil storage tank 302, a hydraulic regulating valve 303, a servo motor 304, and a high-pressure oil pipe 305. Each servo motor 304 is mainly used to provide pressure to each connected hydraulic cylinder 301; each hydraulic regulating valve 303 is used to control the opening and closing and flow direction of the connected high-pressure oil pipe 305; the oil storage tank is used to store hydraulic oil; the high-pressure oil pipe 305 is connected to the corresponding hydraulic cylinder 301, transmitting hydraulic pressure to the hydraulic cylinder 301. The hydraulic cylinder 301 abuts against the force transmission rod 16, thereby transmitting the hydraulic pressure to the pressurizing frame 1 through the force transmission rod 16, so as to transmit the load applied by the hydraulic cylinder 301 to the internal structure of the frame.

[0023] In this embodiment, see Figure 1 Hydraulic cylinders 301 are evenly arranged radially along the pressure frame 1, and force transmission rods 16 are arranged in sets every 11.25° along the circumference of the pressure frame 1. The hydraulic cylinders 301 are arranged corresponding to the force transmission rods 16. Figure 6 The load applied by the hydraulic cylinder 301 can be equivalently converted into the load applied to the surrounding rock of the simulated tunnel 8.

[0024] In summary, by arranging multiple high-precision hydraulic cylinders 301 around the pressure frame 1, loads from different directions and of adjustable size can be applied flexibly and accurately, thereby realistically simulating the complex surrounding rock pressure state actually borne by the roadway 8. The hydraulic cylinders 301 are evenly arranged along the circumference, with one cylinder every 11.25° from the vertical direction to both sides. This angle arrangement allows for flexible combinations of loading directions, accurately simulating any asymmetric load, eliminating stress concentration blind spots, achieving continuous coverage in the full circumference, and avoiding local stress distortion.

[0025] Based on the above embodiments, see Figure 1 , 3To ensure that the force applied by the hydraulic cylinder 301 is evenly transmitted into the simulated tunnel 8, in addition to arranging the force transmission rods 16 at equal intervals on the pressure frame 1, a force transmission frame 2 is also provided. The inside of the force transmission frame 2 is hollow and closed to form a vacuum force transmission cavity 17. The shape of the force transmission frame 2 is consistent with the shape of the pressure frame 1. The outer wall of the force transmission frame 2 is closely attached to the inner wall of the pressure frame 1. A vacuum valve 18 communicating with the force transmission cavity is provided on the force transmission frame 2.

[0026] The force transmission frame 2 is made of welded steel plates and includes two sets of cylinders with different inner diameters and two sets of rings. The two sets of cylinders are placed concentrically with a gap between them. The two sets of cylinders are the inner and outer cylinders of the force transmission frame 2. The two sets of rings are located at the bottom and top of the two sets of cylinders, respectively. The two sets of cylinders and the two sets of rings are connected by welding. During welding, the force transmission component 4 is first welded to the bottom ring, and then the two sets of cylinders are welded to the bottom ring to form a "U" shape. A through hole is opened on the top ring, and the vacuum valve 18 is inserted into the through hole and fixed to the top ring with a nut. After the installation of the vacuum valve 18 is completed, the top ring is welded to the two sets of cylinders to seal the top, so that the inside of the force transmission frame 2 is in a closed state.

[0027] Both sets of cylinders and both sets of rings are made of Q690 high-strength steel with a thickness of 2mm.

[0028] Based on the above embodiments, see Figure 1 , 3 The force transmission component 4 includes a force transmission steel block, which is installed inside the vacuum force transmission cavity 17. The outer force transmission steel block blocks the gap between the inner force transmission steel blocks.

[0029] In this embodiment, three layers of force-transmitting steel blocks are arranged within the vacuum force-transmitting cavity 17, with each layer of force-transmitting steel blocks being circular in shape. The force-transmitting steel blocks in each layer are spaced apart, and the middle layer blocks block the gaps between the inner and outer layers. Figure 3 As shown, gaps are left between the inner, middle and outer layers of force-transmitting steel blocks to form interlayer gaps 5. The thickness of the force-transmitting steel blocks is 10mm. The force-transmitting steel blocks are connected to the bottom ring of the force-transmitting frame 2 by welding.

[0030] Further, see Figure 3The interlayer gaps 5 between adjacent force-transmitting steel blocks increase sequentially from the inside out, being 10mm, 10.25mm, and 10.5mm respectively. The multi-layer steel block assembly can gradually and evenly transfer the load applied by the hydraulic cylinder 301 to the model, effectively avoiding the load concentration phenomenon caused by the force transmission rod 16 not being able to fully contact the model surface. In addition, after connecting the external vacuum equipment to the vacuum valve 18 and evacuating the inside of the force transmission frame 2, when subjected to the load of the hydraulic cylinder 301, the steel block assembly is compressed inward. At this time, the vacuum gap between the interlayer steel blocks can ensure that the steel blocks in the same layer do not come into contact, so that the applied load will not change due to the contact of the steel blocks in the same layer.

[0031] Based on the above embodiments, see Figure 1 , 5 The model body 6 includes a model partition 601, which is located at the center of the force transmission frame 2. The infill body 7 is filled between the model partition 601 and the force transmission frame 2, and the upper end face of the infill body 7 is flush with the upper end face of the force transmission frame 2. The model partition 601 is used to shape the tunnel outline. The model partition 601 must be positioned strictly according to the design dimensions and firmly fixed in order to accurately define the final tunnel geometry and its size ratio, ensure that the model partition 601 is accurately positioned and reliably fixed, and prevent displacement during the pouring process.

[0032] Since the tunnel is mostly an arched passage at the top, the shape of the model partition 601 is consistent with the shape of the tunnel. When the model partition 601 is installed on the bottom partition 14, the pressure frame 1 and the force transmission frame 2 are placed on the bottom partition 14 in advance, the center of the pressure frame 1 is determined, the bottom partition 14 is installed at the determined center point, and a hole is drilled in the middle of the bottom partition 14 and a stud is installed to abut against the inner wall of the model partition 601, thereby fixing the position of the model partition 601.

[0033] The filler 7 is a slurry made of quartz sand, cement, gypsum, water-reducing agent, and retarder. This slurry is poured between the force transmission frame 2 and the model partition 601. At a critical moment when the slurry has initially solidified but not yet fully hardened, pressure sensors 10 are accurately embedded at key locations (such as the roof, sides, and floor) near the surrounding rock of the simulated tunnel 8 formed by the model partition 601. The embedding process requires gentle handling to ensure the sensor's position and orientation accurately meet the monitoring scheme requirements and that the sensor's sensitive element makes good contact with the surrounding rock slurry. The sensor wires must be carefully led out of the device, marked, and temporarily fixed to prevent damage from pulling during subsequent curing or experiments. After the sensors are embedded, the cast-in-place model is immediately cured. Only after reaching the expected strength can the model undergo subsequent loading tests. The signal and power lines of the pressure sensor pre-embedded inside the sample are connected to the pressure signal acquisition instrument. The acquisition instrument is then connected to the PC computer 22. The sampling frequency and data storage path are set in the acquisition software, and the acquisition instrument is zeroed. After starting the data acquisition instrument, observe whether the pressure signal is displayed normally, and at the same time check the wiring connection status to eliminate any possible abnormalities. This process is used to continuously monitor the stress state around simulated roadway 8.

[0034] In one embodiment, see Figure 4 It also includes a support bracket 19, which is located above the pressure frame 1. The monitor 12 includes a high-definition camera mounted on the support bracket 19. The high-definition camera is aimed at the model under test, and the aperture and focal length are adjusted to make the shooting range cover the entire model and the image clear. The camera is connected to the PC computer 22, the speckle analysis software is opened, the high-definition camera is connected, the shooting interval time is set, and the speckle monitoring and analysis function is turned on, so as to monitor the strain field changes on the entire surface of the model.

[0035] One strain gauge is attached to the loading area of ​​each hydraulic cylinder 301, such as Figure 2 As shown, attach the strain gauges to the outer wall of the overall frame, close to the inner wall of the device, directly opposite the hydraulic cylinders 301. Each hydraulic cylinder 301 corresponds to one strain gauge for monitoring the real-time load applied to the model by the hydraulic cylinder 301. The installation and wiring method is as follows... Figure 5 The strain gauge is connected to signal amplifier 20 via a circuit to amplify the original strain gauge signal. The output of signal amplifier 20 is then connected to signal converter 21, and the output of signal converter 21 is connected to PC computer 22 for storing and analyzing the strain gauge voltage signal. The accompanying software is run to display the real-time load applied to the experimental model by hydraulic cylinder 301.

[0036] The present invention provides a test apparatus for multi-directional simulation control of roadway confining pressure, which includes the following steps when conducting roadway confining pressure tests: Step 1: Based on the specific conditions of the studied site, extract the following information: ① Define the simulation scope: Based on in-depth exploration and engineering analysis of the target mine roadways, clarify the roadway sections to be simulated and their influence range. This includes determining the spatial location, geometric characteristics, and surrounding rock areas that need to be studied. Reasonably defining the simulation scope is a prerequisite for ensuring that the test results effectively reflect the actual site conditions. ② Obtain the original geostress: The loading boundary conditions of the model must realistically reflect the geostress environment at the site. Therefore, in-situ tests need to be conducted at the roadway site in the study area to directly measure and obtain the original data of the original rock stress field. ③ Apply similarity theory: The core of physical model testing lies in the similarity of the mechanical behavior of the model and the prototype. Therefore, the basic principles and similarity criteria of similarity theory must be strictly followed.

[0037] Based on the physical nature of the research problem, key similarity criteria are determined, and necessary similarity parameters such as dimensional similarity ratio are set and calculated accordingly. Stress similarity ratio Density similarity ratio Calculate parameters such as model size l, model density ρ, and model boundary force σ; The similarity conditions are as follows: .

[0038] Step 2: Based on the similarity ratio parameters determined by similarity theory, study suitable similar materials, refer to previous research results, and use commonly used similar material raw materials (quartz sand, cement, gypsum, water-reducing agent, retarder, etc.) to explore suitable similar material preparation formulas and curing methods through orthogonal experiments.

[0039] Step 3: Constructing the Experimental Model. ① Device Preparation and Model Positioning: Place the experimental device stably on a sturdy workbench 13, ensuring it is level to prevent deformation or uneven stress on the model due to device tilting during subsequent operations. Lay a pre-prepared bottom partition 14 at the bottom of the device. This bottom partition 14 provides an initial support surface and facilitates subsequent model demolding. ② Based on the precise dimensional parameters calculated in Step 1, place the model partition 601 for shaping the tunnel outline within the internal space of the device. The model partition 601 must be strictly positioned and firmly fixed according to the design dimensions to accurately define the final tunnel geometry and its dimensional proportions, ensuring accurate and reliable partition positioning and preventing displacement during the pouring process. ③ Similar Material Preparation and Pouring: Based on the optimal similar material formula determined in Step 2, accurately weigh the required raw materials. ④ According to the determined mixing sequence and process, thoroughly prepare a uniformly mixed and appropriately sized similar material slurry. Carefully pour the prepared slurry into the prepared device. ⑤ Sensor Installation: At the critical juncture when the filling grout has initially solidified but not yet fully hardened, accurately embed pressure cell sensors at key locations near the surrounding rock of the roadway (such as the roof, sides, and floor). The installation process must be handled gently to ensure the sensor's position and orientation accurately meet the monitoring plan requirements, and to ensure good contact between the sensor's sensitive element and the surrounding rock material. The sensor wires must be carefully led out of the device, marked, and temporarily secured to prevent damage from pulling during subsequent curing or experiments. ⑥ Model Curing: After the sensors are installed, immediately cure the poured similar model according to the optimal curing method verified in step two. Only after the model reaches the expected strength can subsequent loading tests be conducted.

[0040] Step 4: Deploy the monitoring system, consisting of three systems. ① Internal pressure monitoring system: Connect the signal and power lines of the pressure cell sensor pre-embedded in the sample to the pressure signal acquisition instrument, and connect the acquisition instrument to PC 22. Set the sampling frequency and storage path; clear the data, turn on the acquisition instrument, observe whether the pressure signal is normal, check the circuit, and eliminate any abnormalities. This is used to monitor the stress state of the surrounding rock in the simulated tunnel 8. ② Speckle surface strain monitoring system: Spray calibration speckles 9 onto the front surface of the model (a surface without any obstructions). Set up the speckle strain measurement system above the model, including setting up a camera bracket, adjusting the camera sliding rail for leveling, and installing a high-speed, high-definition camera. Rotate and translate the camera to align with the model under test, adjust the aperture and focal length to ensure the shooting range covers the entire model and the image is clear. Connect the camera to PC 22, open the speckle analysis software, connect the camera, set the shooting interval, and turn on the speckle monitoring and analysis function. This is used to monitor the strain field changes across the entire surface of the model. ③ Real-time load monitoring system for hydraulic cylinder 301: Strain sensor 11 (strain gauge) is attached to a designated position on the overall frame and wired to signal amplifier 20. The amplified signal is then connected to data acquisition card and finally transmitted to PC computer 22. The accompanying software is run to monitor the load data of hydraulic cylinder 301 in real time.

[0041] Step 5: Hydraulic System Start-up and Load Application. ① System Start-up: Start the servo motor 304 of the hydraulic loading system to provide power for the entire loading process. ② Target Setting: Based on the experimental plan and the actual conditions of the model, set a predetermined load target value for each hydraulic cylinder 301 in the control system. ③ Load Application: Input hydraulic oil of the corresponding flow rate into each hydraulic cylinder 301 through the connected high-pressure oil pipe 305. The system will automatically adjust the oil pressure and flow rate according to the set load value, driving the cylinder piston to move and smoothly and accurately apply the load to the experimental model until the predetermined load value of each cylinder is reached. Close monitoring of the pressure gauge readings and the feedback from the control system is necessary during this process.

[0042] Step Six: Load Maintenance, Unloading, and Experimental Conclusion. ① Load Control: Based on the experimental design requirements and the actual response of the model, control the load to maintain the target value for a set duration to simulate actual working conditions or observe specific phenomena. ② Achieving the Objective and Unloading: Once the experimental objective is achieved, begin the unloading process. Operate the hydraulic servo control system to orderly depressurize the system, allowing the load on each hydraulic cylinder 301 to smoothly and gradually decrease to zero from its current value. ③ Model Disassembly and Cleaning: After the load is completely removed and the system is confirmed to be safe, carefully remove the damaged experimental model. Then, thoroughly clean the experimental platform, cylinders, and surrounding area, removing any experimental residue. ④ Facility Reset: Finally, check, return, or restore all used instruments and equipment to their initial standby state, ensuring the experimental setup is clean and intact, preparing for subsequent experiments.

[0043] Step Seven: Process Observation and Data Acquisition Analysis. ① Deformation Monitoring: Throughout the loading process, continuously and carefully observe the deformation development of the surrounding rock structure in simulated tunnel 8, recording any visible crack generation, propagation, spalling, or overall displacement. ② Data Acquisition and Recording: Simultaneously utilize pre-deployed sensors and a data acquisition system to collect and record key experimental data in real time. ③ Data Analysis: After the experiment, based on the collected stress and strain data, perform subsequent data processing, calculations, and comprehensive analysis. The aim is to study the mechanical response characteristics, stress distribution patterns, strain evolution process, and final failure modes of the tunnel's surrounding rock, providing a basis for research or engineering applications.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test device for multi-directional simulation control of roadway confining pressure, characterized in that: include: The pressurization assembly includes a pressurization frame (1) and a force transmission frame (2) disposed within the pressurization frame (1); multiple sets of pressurization components (3) are provided at equal intervals on the outside of the pressurization frame (1); multiple sets of force transmission components (4) are provided at intervals along the circumference of the force transmission frame (2) within the force transmission frame (2); the force transmission components (4) are provided in multiple layers from the inside to the outside along the radial direction of the force transmission frame (2), and interlayer gaps (5) are formed between adjacent force transmission components (4) and are in a vacuum state; The model assembly includes a model body (6) located at the center of the force transmission frame (2) and a filler (7) located between the model body (6) and the force transmission frame (2); the model body (6) is hollow inside to form a simulated tunnel (8); the surface of the filler (7) is provided with calibration speckles (9). The monitoring components include multiple sets of pressure sensors (10) disposed in the filler (7), multiple sets of strain sensors (11) disposed on the force transmission component (4), and a monitor (12) disposed above the filler (7); the pressure sensors (10) are distributed around the model body (6); the strain sensors (11) are disposed near the filler (7); the pressurizing component (3) transmits the force evenly to the filler (7) through the force transmission component (4) under the action of external force, and monitors the force through the pressure sensors (10) and strain sensors (11) and transmits the values ​​to the external control system; the monitor (12) is used to monitor the stress field change of the calibrated speckle (9) on the surface of the filler (7) and transmit it to the external control system.

2. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 1, characterized in that: The pressure frame (1) is a ring made of steel plate and steel beam welded together; the outer wall of the pressure frame (1) is provided with a pressure hole (15); a force transmission rod (16) is installed in the pressure hole (15).

3. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 2, characterized in that: The pressurizing component (3) includes a hydraulic cylinder (301); the hydraulic cylinder (301) abuts against the force transmission rod (16).

4. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 3, characterized in that: The hydraulic cylinders (301) are evenly arranged radially along the pressure frame (1); the force transmission rods (16) are arranged in a group at 11.25° intervals along the circumference of the pressure frame (1); the hydraulic cylinders (301) are arranged corresponding to the force transmission rods (16).

5. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 4, characterized in that: The force transmission frame (2) is hollow and closed to form a vacuum force transmission cavity (17); the shape of the force transmission frame (2) is consistent with the shape of the pressure frame (1), the outer wall of the force transmission frame (2) is closely attached to the inner wall of the pressure frame (1), and the force transmission frame (2) is provided with a vacuum valve (18) that communicates with the force transmission cavity.

6. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 5, characterized in that: The force transmission component (4) includes a force transmission steel block; the force transmission steel block is installed in the vacuum force transmission cavity (17), and the force transmission steel block located on the outer layer blocks the gap between the force transmission steel blocks located on the inner layer.

7. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 6, characterized in that: The interlayer gap (5) between the adjacent force-transmitting steel blocks increases sequentially from the inside to the outside.

8. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 7, characterized in that: The model body (6) includes a model partition (601); the model partition (601) is located at the center of the force transmission frame (2); the filler (7) is filled between the model partition (601) and the force transmission frame (2) and the upper surface of the filler (7) is flush with the upper surface of the force transmission frame (2).

9. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 8, characterized in that: It also includes a support bracket (19); the support bracket (19) is located above the pressure frame (1); the monitor (12) includes a high-definition camera mounted on the support bracket (19).

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