A multi-directional analog control roadway confining pressure test device and method

Abstract

The application discloses a kind of multi-directional simulation control roadway confining pressure test device and method, it is related to rock mechanics and mining engineering technical field, including pressurizing component, model component, monitoring component, pressurizing component includes pressurizing frame, force transmission frame, multiple groups of pressurizing piece, multiple groups of force transmission piece;Model component includes model body, filling body;Model body inside is formed simulation roadway;The surface of filling body is equipped with calibration speckle;Monitoring component includes multiple groups of pressure sensor, multiple groups of strain sensor, monitor;By setting multiple groups of hydraulic cylinder, the model is pressurized, realizes multi-direction, independently controllable loading capacity, flexibly, accurately exert from different direction, size adjustable load, highly realistic simulation roadway actual complex surrounding rock pressure state, hydraulic cylinder is evenly arranged along circumference, realizes the flexible combination of loading direction, accurately simulates arbitrary asymmetric load, multiple groups of force transmission piece can be evenly transmitted to model on external load, eliminate stress concentration blind area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock mechanics and mining engineering, and particularly relates to a test device and method for simulating and controlling roadway surrounding pressure in multiple directions. BACKGROUND

[0002] The stability of a roadway, which is the core channel for mine production, is of great importance. However, large deformation and even collapse of the roadway often occurs, which seriously threatens the normal production order and the safety of personnel and equipment in the mine. In-depth analysis shows that the surrounding rock pressure of the roadway is the main factor inducing deformation and even destruction of the roadway. Especially in the roadway with weak or failed support, the surrounding rock pressure is easy to cause local stress concentration and induce accidents such as sudden collapse of individual rock blocks, thus constituting a major safety hazard. In recent years, the dual effects of abnormal increase of the surrounding rock pressure of the roadway and insufficient bearing capacity of the support structure have caused many serious accidents, resulting in heavy casualties and huge economic losses. The decisive influence of the surrounding rock pressure on the stability of the roadway also highlights the extreme importance of scientific and reasonable support design of the roadway for ensuring the safety of mine production and personnel life. Therefore, in order to prevent such accidents from the source and ensure long-term stability of the mine, it is necessary to accurately simulate and predict the deformation response of the roadway under the action of the real surrounding pressure in the early stage of construction and maintenance of the roadway, so as to provide a solid scientific basis for the optimized design of the support scheme.

[0003] The currently widely used test device for simulating the surrounding pressure of the roadway has significant limitations: the loading mode is mostly one-way or two-way, that is, only the load in the vertical direction (such as the roof pressure) or the load in the vertical direction plus the lateral direction (such as the pressure of the two sides) can be simulated. This simplified model cannot accurately reproduce the complex three-dimensional stress environment (i.e. multi-directional and non-uniform pressure from the roof, floor and two sides) of the actual roadway, resulting in deviation between the simulation results and the actual engineering, and failing to provide sufficient reliable guidance for the support design. SUMMARY

[0004] The main purpose of the present application is to provide a test device and method for simulating and controlling the surrounding pressure of the roadway in multiple directions, which can solve the problem that the existing test device for simulating the surrounding pressure of the roadway cannot accurately reproduce the complex three-dimensional stress environment of the actual roadway.

[0005] To achieve the above purpose, the present application provides a test device for simulating and controlling the surrounding pressure of the roadway in multiple directions, which comprises:

[0006] The pressure assembly comprises a pressure frame and a force transmission frame arranged in the pressure frame; a plurality of groups of pressure pieces are arranged at equal intervals outside the pressure frame; a plurality of groups of force transmission pieces are arranged at equal intervals along the circumference of the force transmission frame in the force transmission frame; a plurality of layers of force transmission pieces are arranged at equal intervals along the radial direction of the force transmission frame from the inside to the outside, and the layer gaps between adjacent force transmission pieces are in a vacuum state.

[0007] The model assembly comprises a model body arranged at the center of the force transmission frame and a filling body arranged between the model body and the force transmission frame; the model body is hollow inside to simulate a roadway; and the surface of the filling body is provided with calibrated speckle points.

[0008] The monitoring assembly comprises a plurality of groups of pressure sensors arranged in the filling body, a plurality of groups of strain sensors arranged on the force transmission member, and a monitor arranged above the filling body; the pressure sensors are distributed around the model body; the strain sensors are arranged adjacent to the filling body; the pressure member uniformly transmits the external force to the filling body through the force transmission member under the action of the external force, and the pressure and strain sensors monitor the action force and transmit the values to the external control system; and the monitor is used for monitoring the stress field change of the calibrated speckle points on the surface of the filling body and transmitting the values to the external control system.

[0009] As a further improvement of the present application, the pressure frame is a circular ring composed of a steel plate and a steel beam; the outer wall of the pressure frame is provided with a pressure hole; and the pressure hole is provided with a force transmission rod.

[0010] As a further improvement of the present application, the pressure member comprises a hydraulic oil cylinder; and the hydraulic oil cylinder is in abutment with the force transmission rod.

[0011] As a further improvement of the present application, the hydraulic oil cylinders are uniformly arranged along the radial direction of the pressure frame; one group of force transmission rods is arranged every 11.25° along the circumferential direction of the pressure frame; and the hydraulic oil cylinders are arranged corresponding to the force transmission rods.

[0012] As a further improvement of the present application, the force transmission frame is hollow and closed to form a vacuum transmission cavity; the shape of the force transmission frame is consistent with that of the pressure frame, the outer wall of the force transmission frame is arranged in close contact with the inner wall of the pressure frame, and the force transmission frame is provided with a vacuum valve communicating with the vacuum transmission cavity.

[0013] As a further improvement of the present application, the force transmission member comprises force transmission steel blocks; the force transmission steel blocks are arranged in the vacuum transmission cavity, and the outer force transmission steel blocks shield the gaps between the inner force transmission steel blocks.

[0014] As a further improvement of the present application, the interlayer gaps between the adjacent force transmission steel blocks increase from inside to outside.

[0015] As a further improvement of the present application, the model body comprises a model partition plate; the model partition plate is located at the center of the force transmission frame; and the filling body is filled between the model partition plate and the force transmission frame, and the upper end surface of the filling body is flush with the upper end surface of the force transmission frame.

[0016] As a further improvement of the present application, a support bracket is further included; the support bracket is located above the pressure frame; and the monitor comprises a high-definition camera arranged on the support bracket.

[0017] The beneficial effects of the present application are embodied in:

[0018] By setting multiple groups of hydraulic oil cylinders to pressurize the model, multi-directional and independently controllable loading capacity is realized, and loads from different directions and sizes can be flexibly and accurately applied, thereby highly realistically simulating the complex surrounding rock pressure state actually borne by the roadway, the hydraulic oil cylinders are evenly arranged along the circumference, the flexible combination of the loading direction can be realized, the arbitrary asymmetric load can be accurately simulated, multiple groups of force transmission members are set, the external load can be uniformly transmitted to the model, the stress concentration blind area is eliminated, the full circumferential continuous coverage is realized, and local stress distortion is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a whole structure schematic view of the test device for simulating and controlling the surrounding pressure of the roadway in multiple directions according to the present application;

[0020] Figure 2 It is a strain sensor mounting structure schematic view of the test device for simulating and controlling the surrounding pressure of the roadway in multiple directions according to the present application;

[0021] Figure 3 It is an internal structure schematic view of the force transmission member of the test device for simulating and controlling the surrounding pressure of the roadway in multiple directions according to the present application;

[0022] Figure 4 It is a support bracket structure schematic view of the test device for simulating and controlling the surrounding pressure of the roadway in multiple directions according to the present application;

[0023] Figure 5 It is a connection structure schematic view of the test device for simulating and controlling the surrounding pressure of the roadway in multiple directions according to the present application and a PC computer;

[0024] Figure 6 It is a loading equivalent view of the test device for simulating and controlling the surrounding pressure of the roadway in multiple directions according to the present application;

[0025] REFERENCE SIGNS:

[0026] 1, pressurizing frame; 2, force transmission frame; 3, pressurizing member; 301, hydraulic oil cylinder; 302, oil storage cabin; 303, hydraulic adjusting valve; 304, servo motor; 305, high-pressure oil pipe; 4, force transmission member; 5, interlayer gap; 6, model body; 601, model partition plate; 7, filling body; 8, simulated roadway; 9, calibration speckle point; 10, pressure sensor; 11, strain sensor; 12, monitor; 13, workbench surface; 14, bottom partition plate; 15, pressurizing hole; 16, force transmission rod; 17, vacuum force transmission cavity; 18, vacuumizing valve; 19, support bracket; 20, signal amplifier; 21, signal converter; 22, PC computer. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The embodiments in the present application and the features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] Referring to Figure 1 , a multi-directional simulation control roadway confining pressure test device of the present application comprises a pressurizing assembly, a model assembly and a monitoring assembly.

[0029] The pressurizing assembly comprises a pressurizing frame 1 and a force transmission frame 2 arranged in the pressurizing frame 1. A plurality of sets of pressurizing members 3 are arranged at equal intervals outside the pressurizing frame 1. A plurality of sets of force transmission members 4 are arranged at equal intervals along the circumference of the force transmission frame 2 inside the force transmission frame 2. The force transmission members 4 are arranged at multiple layers along the radial direction of the force transmission frame 2 from inside to outside. The adjacent force transmission members 4 form interlayer gaps 5 and are in a vacuum state. The model assembly comprises a model body 6 arranged at the center of the force transmission frame 2 and a filling body 7 arranged between the model body 6 and the force transmission frame 2. The model body 6 is hollow inside to form a simulated roadway 8. The surface of the filling body 7 is provided with calibrated speckle points 9. The monitoring assembly comprises a plurality of sets of pressure sensors 10 arranged in the filling body 7, a plurality of sets of strain sensors 11 arranged on the force transmission members 4 and a monitor 12 arranged above the filling body 7. The pressure sensors 10 are distributed around the model body 6, and the strain sensors 11 are arranged close to the filling body 7. The pressurizing members 3 uniformly transmit the acting force to the filling body 7 through the force transmission members 4 under the action of external force. The acting force is monitored by the pressure sensors 10 and the strain sensors 11 and the numerical value is transmitted to the external control system. The monitor 12 is used to monitor the stress field change of the calibrated speckle points 9 on the surface of the filling body 7 and transmit the value to the external control system.

[0030] In order to solve the inherent defects of the single and double direction loading device, a new type of simulation test device is developed. The core advantage of the device is to realize the multi-directional and independently controllable loading capacity, and a set of force transmission system suitable for circumferential loading is developed. By arranging a plurality of high-precision hydraulic cylinders 301 around the roadway model, the load from different directions and sizes can be flexibly and accurately applied, thereby highly realistically simulating the complex surrounding rock pressure state actually borne by the roadway 8. The hydraulic cylinders 301 are uniformly arranged along the circumference, can realize flexible combination of the loading direction, accurately simulate any asymmetric load, can eliminate the stress concentration blind area, realize full circumferential continuous coverage, and avoid local stress distortion.

[0031] In the present embodiment, referring to Figure 1 , 4The whole experimental device is stably placed on a solid workbench 13 to ensure that it is in a horizontal state, avoids model deformation or uneven stress due to device inclination in subsequent operations, and a pre-prepared bottom partition plate 14 is laid at the bottom of the device. The bottom partition plate 14 provides an initial support surface and facilitates subsequent model demolding.

[0032] In the embodiment, the pressurizing frame 1 is a circular ring composed of thick steel plates and steel beams welded together. The thickness of the pressurizing frame 1 is 70mm-90mm, preferably 80mm. The outer wall of the pressurizing frame 1 is provided with pressurizing holes 15, and the force transmission rods 16 are installed in the pressurizing holes 15.

[0033] In the embodiment, referring to Figure 1 , the pressurizing member 3 adopts a hydraulic loading system, including hydraulic cylinders 301, oil storage tanks 302, hydraulic regulating valves 303, servo motors 304, and high-pressure oil pipes 305. Each servo motor 304 is mainly used to provide pressure for the 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 to transmit hydraulic pressure to the hydraulic cylinder 301. The hydraulic cylinder 301 abuts against the force transmission rod 16, so as to transmit 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.

[0034] In the embodiment, referring to Figure 1 , the hydraulic cylinders 301 are uniformly arranged along the radial direction of the pressurizing frame 1, and the force transmission rods 16 are arranged in groups every 11.25° along the circumferential direction of the pressurizing frame 1. The hydraulic cylinders 301 are arranged corresponding to the force transmission rods 16, as shown in Figure 6 , the load applied by the hydraulic cylinder 301 can be equivalent to the load applied to the surrounding rock of the simulated roadway 8.

[0035] In summary, by arranging multiple high-precision hydraulic cylinders 301 around the pressurizing frame 1, loads from different directions and sizes can be flexibly and accurately applied, thereby highly realistically simulating the complex surrounding rock pressure state actually borne by the roadway 8. The hydraulic cylinders 301 are uniformly arranged along the circumference, one every 11.25° to the left and right from the vertical direction. This angle arrangement can realize flexible combination of loading directions, accurately simulate any asymmetric load, eliminate stress concentration blind area, realize full circumferential continuous coverage, and avoid local stress distortion.

[0036] On the basis of the above embodiment, referring to 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.

[0037] 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.

[0038] Both sets of cylinders and both sets of rings are made of Q690 high-strength steel with a thickness of 2mm.

[0039] 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.

[0040] 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.

[0041] Further, see Figure 3, the interlayer gap 5 between adjacent force transmission steel blocks increases from inside to outside in turn, being 10 mm, 10.25 mm and 10.5 mm respectively, the multi-layer steel block combination can gradually and uniformly transmit the load applied by the hydraulic oil cylinder 301 to the model, effectively avoiding the load concentration phenomenon caused by the fact that the force transmission rod 16 cannot fully contact the surface of the model, in addition, after the inside of the force transmission frame 2 is connected with the vacuumizing valve 18 and vacuumized by the external vacuum equipment, when subjected to the load of the hydraulic oil cylinder 301, the steel block combination 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 contact each other, so that the applied load will not change due to the contact between the steel blocks in the same layer.

[0042] Based on the above embodiment, see Figure 1 、 5 , the model body 6 includes a model partition plate 601 located at the center of the force transmission frame 2, and the filling body 7 is filled between the model partition plate 601 and the force transmission frame 2, and the upper end surface of the filling body 7 is flush with the upper end surface of the force transmission frame 2, the model partition plate 601 is used to shape the profile of the roadway, and the model partition plate 601 needs to be positioned strictly according to the design size and firmly fixed to accurately define the geometric shape of the roadway formed by final pouring and its size ratio, ensure the accurate position and reliable fixation of the model partition plate 601, and prevent displacement during pouring.

[0043] Since the shape of the roadway is mostly a channel with a circular arch at the upper part, the shape of the model partition plate 601 is consistent with the shape of the roadway, when the model partition plate 601 is installed on the above-mentioned bottom partition plate 14, the pressurizing frame 1 and the force transmission frame 2 are placed on the bottom partition plate 14 in advance, the center of the pressurizing frame 1 is determined, the bottom partition plate 14 is installed at the determined center point, and a hole is punched in the middle of the above-mentioned bottom partition plate 14 and a stud is installed to abut against the inner wall of the model partition plate 601, thereby fixing the position of the model partition plate 601.

[0044] The filling body 7 is formed by mixing quartz sand, cement, gypsum, water reducing agent and retarder, the slurry is poured into the force transmission frame 2 and the model partition plate 601, at the critical moment when the slurry is initially solidified but not completely hardened, the pressure sensor 10 is accurately buried at the critical position (such as the roof, two sides and the floor) near the surrounding rock of the simulated roadway 8 formed by the model partition plate 601, the burying process needs to be operated gently, the position and direction of the sensor are ensured to be accurate and meet the requirements of the monitoring scheme, and the sensor sensitive element is ensured to be in good contact with the surrounding rock slurry, the sensor wire needs to be carefully led out of the device and temporarily fixed with good marking to avoid being pulled and damaged in subsequent maintenance or experiments; after the sensor is buried, the completed similar model is immediately maintained; after the expected strength is reached, the model can be subjected to subsequent loading experiments; the signal line and power line of the pre-buried pressure box sensor in the sample are connected to the pressure signal acquisition instrument. Then, the acquisition instrument is 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 acquisition instrument, whether the pressure signal is normally displayed is observed, and the connection state of the line is checked to exclude possible abnormal situations. This process is used for continuously monitoring the stress state of the surrounding rock of the simulated roadway 8.

[0045] In an embodiment, referring to Figure 4 It also includes a support bracket 19 located above the pressurizing frame 1, the monitor 12 includes a high-definition camera mounted on the support bracket 19, the high-definition camera is aimed at the measured model, the aperture and focal length are adjusted so that the shooting range is the full range of the model and the image is 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 started, which is used for monitoring the strain field change of the full surface of the model.

[0046] A strain gauge is pasted in the position corresponding to each hydraulic oil cylinder 301, as Figure 2 The strain gauge is pasted to the outer wall of the overall frame, the position is close to the inner wall of the device and directly opposite the hydraulic oil cylinder 301, and one strain gauge is used for monitoring the real-time load applied to the model by the hydraulic oil cylinder 301. The installation wiring method is as Figure 5 The strain gauge is connected to the signal amplifier 20 through a circuit for amplifying the original signal of the strain gauge. The output end of the signal amplifier 20 is connected to the signal converter 21, and then the output end of the signal converter 21 is connected to the PC computer 22 for storing and analyzing the voltage signal of the strain gauge. The matching software is run to display the real-time load applied to the experimental model by the hydraulic oil cylinder 301 in real time.

[0047] The test device for simulating and controlling the surrounding pressure of a roadway in multiple directions of the application comprises the following steps when the surrounding pressure test of the roadway is performed:

[0048] Step one: According to the specific circumstances of the site, the following information extraction. ① delineate the simulation range: based on the in-depth investigation and engineering analysis of the target mine roadway, clear need to simulate the roadway section and its impact. This includes determining the spatial location of the roadway, geometric characteristics and the need for key research of surrounding rock area. Reasonable delineation of simulation range is to ensure that the test results effectively reflect the premise of the actual site. ② get the original stress: the loading boundary conditions of the model must reflect the actual stress environment of the site. Therefore, the need to study the area of the roadway in situ test, direct measurement of the original data of the original rock stress field. ③ application of similarity theory: the core of the physical model test is the mechanical behavior of the model and prototype similar. Therefore, we must strictly follow the basic principles and similarity criteria of similarity theory.

[0049] According to the physical nature of the research problem, determine the key similarity criterion, and set and calculate the necessary similarity parameters such as size similarity ratio , stress similarity ratio , density similarity ratio and so on, calculate the model size l, model density p and model boundary force s and other parameters;

[0050] Among them, the similarity condition is: .

[0051] Step two: according to the similarity ratio parameters determined by the similarity theory, study the appropriate similar material, refer to the research results of predecessors, use the commonly used similar material raw materials (quartz sand, cement, gypsum, water reducing agent, retarder, etc.), through orthogonal test, explore the appropriate similar material production formula and maintenance method.

[0052] Step three: construction of experimental model. ① Device preparation and model positioning: Place the experimental device steadily on a solid workbench 13, ensuring it is level to avoid deformation or uneven stress of the model during subsequent operations. Lay the 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 According to the accurate size parameters calculated in step one, place the model partition 601 used to shape the roadway profile in the internal space of the device; the model partition 601 needs to be positioned and firmly fixed according to the design size to accurately define the geometric shape and size ratio of the roadway formed by the final pouring, ensuring accurate positioning and reliable fixation of the partition to prevent displacement during pouring. ③ Similar material preparation and pouring: According to the optimal similar material formula determined in step two, accurately measure the required raw materials. ④ According to the determined mixing order and process, fully prepare the mixed and uniform similar material slurry with appropriate state. Carefully pour the prepared slurry into the prepared device. ⑤ Sensor layout: At the critical moment when the filled slurry is initially solidified but not completely hardened, accurately bury the pressure cell sensor near the key positions (such as the roof, two sides, and floor) of the surrounding rock of the roadway. The burying process needs to be gentle to ensure that the sensor position and direction accurately meet the monitoring plan requirements and that the sensor sensitive element is in good contact with the surrounding rock similar material. The sensor leads need to be carefully led out of the device and marked and temporarily fixed to avoid being pulled and damaged during subsequent maintenance or experiments. ⑥ Model maintenance: After the sensor is buried, immediately maintain the poured similar model according to the best maintenance method verified in step two. After reaching the expected strength, the model can be subjected to subsequent loading experiments.

[0053] Step four: arrange monitoring system, a total of three systems. ① Internal pressure monitoring system: connect the signal line and power line of the pressure box sensor pre-buried in the sample to the pressure signal acquisition instrument, and connect the acquisition instrument to the PC computer 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 exclude abnormalities, which are used to monitor the stress state of the surrounding rock of the simulated tunnel 8. ② Speckle surface strain monitoring system: spray calibrated speckle points 9 on the front surface of the model (the surface without any shielding). Set up a speckle strain measurement system above the model, including setting up a camera support, adjusting the level of the camera slide rail, and installing a high-speed high-definition camera. Rotate and translate the camera to aim at the measured model, adjust the aperture and focal length, so that the shooting range is the full range of the model, and the image is clear. Connect the camera to the PC computer 22, open the speckle analysis software, connect the camera, set the shooting interval time, and start the speckle monitoring and analysis function, which are used to monitor the strain field change of the whole surface of the model. ③ Real-time load monitoring system of hydraulic oil cylinder 301: paste strain sensors 11 (strain gauges) at specified positions of the overall frame and connect them to signal amplifiers 20, connect the amplified signals to data acquisition cards, finally transmit them to PC computer 22, and run the matching software to monitor the load data of the hydraulic oil cylinder 301 in real time.

[0054] Step five: start the hydraulic system and apply load. ① Start the system: start the servo motor 304 of the hydraulic loading system to provide power for the entire loading process. ② Set the target: according to the experimental scheme and the actual situation of the model, set the predetermined load target value for each hydraulic oil cylinder 301 in the control system. ③ Apply load: through the connected high-pressure oil pipe 305, input the corresponding flow of hydraulic oil to each hydraulic oil cylinder 301. The system will automatically adjust the oil pressure and flow according to the set load value, drive the oil cylinder piston to move, and apply the load smoothly and accurately to the experimental model until the predetermined load value of each oil cylinder is reached. This process needs to pay close attention to the pressure instrument reading and the feedback of the control system.

[0055] Step six: load maintenance, unloading and experiment ending. ① Load control: according to the experimental design requirements and the actual response of the model, control the load to keep at the target value for a set duration to simulate the actual working condition or observe specific phenomena. ② Reach the purpose and unload: when the experimental purpose is achieved, start the unloading process. Operate the hydraulic servo control system to orderly reduce the pressure of the system, so that the load of each hydraulic cylinder 301 starts from the current value and gradually decreases to zero. ③ Model disassembly and cleaning: after the load is completely unloaded and the system is confirmed to be safe, carefully remove the damaged experimental model. Then, thoroughly clean the experimental bench, oil cylinder and surrounding area to remove experimental residues. ④ Facility reset: finally, check all used equipment, return or restore to the initial standby state to ensure that the experimental device is clean and intact, and prepare for subsequent experiments.

[0056] Step seven: process observation and data collection and analysis. ① Deformation monitoring: during the entire loading process, continuously and carefully observe the deformation development of the simulated roadway 8 surrounding rock structure, and record any visible crack generation, expansion, peeling or overall displacement phenomena. ② Data collection and recording: simultaneously use the pre-arranged sensors and data collection system to collect and record key experimental data in real time. ③ Data analysis: after the experiment is completed, based on the collected stress data and strain data, subsequent data processing, calculation and comprehensive analysis are carried out. The purpose is to study the mechanical response characteristics of the surrounding rock of the roadway, the stress distribution law, the strain evolution process and the final failure mode, etc., to provide a basis for research or engineering application.

[0057] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

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 pressure frame (1) is a ring welded from steel plates and steel beams; the outer wall of the pressure frame (1) is provided with pressure holes (15); a force transmission rod (16) is installed in the pressure hole (15); the pressure component (3) includes a hydraulic cylinder (301); the hydraulic cylinder (301) abuts against the force transmission rod (16); the hydraulic cylinders (301) are evenly arranged radially along the pressure frame (1); the force transmission rods (16) are arranged in groups at 11.25° intervals along the circumference of the pressure frame (1); the hydraulic cylinders (301) are evenly arranged radially along the pressure frame (1); the hydraulic cylinders (301) are evenly arranged radially along the pressure frame (1); the force transmission rods (16) are evenly arranged radially along the pressure frame (1) at 11.25° intervals; the hydraulic cylinders (301 ... 01) Arrangement corresponding to the force transmission rod (16); 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) communicating with the force transmission cavity; 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; 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 interlayer gap (5) between the adjacent force-transmitting steel blocks increases sequentially from the inside to the outside.

3. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 2, 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).

4. The experimental device for multi-directional simulation control of roadway confining pressure according to claim 3, 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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