Stability simulation monitoring device for false roof and surrounding rock contact surface based on intelligent sensor

Abstract

The application discloses a false roof and surrounding rock contact surface stability simulation monitoring device based on an intelligent sensor, which comprises a counterforce frame, a flexible loading module, a composite surrounding rock simulation layer, a false roof module, a lateral pressure system and an intelligent sensor network; a roof beam mechanism is arranged on the top of the counterforce frame, and the roof beam mechanism is hinged by a plurality of arc-shaped beams arranged in the transverse direction; the flexible loading module comprises a plurality of floating loading units, each floating loading unit is connected to the corresponding arc-shaped beam below through a universal hinge at the top, and the bottom is connected with a rigid pressing plate through a spherical hinge, and the lower surfaces of a plurality of rigid pressing plates are covered with elastic pads; the composite surrounding rock simulation layer is arranged below the flexible loading module; the false roof module is arranged below the composite surrounding rock simulation layer, and connecting lug plates are arranged at the left and right ends of the false roof module.

Description

Technical Field

[0001] This invention relates to the field of underground engineering simulation and testing technology, specifically to a stability simulation and monitoring device for the contact surface between a false roof and surrounding rock based on intelligent sensors. Background Technology

[0002] In underground mining, the stability of the false roof, as an artificially constructed load-bearing structure, at its contact surface with the fractured surrounding rock directly affects the safety of the entire support system. Roof falls, spalling, and other disasters caused by instability at the contact surface are among the major hazards in underground engineering.

[0003] Existing similar simulation test devices have the following technical shortcomings: First, the loading system mostly uses rigid indenters for uniaxial or biaxial loading, which cannot simulate the multidirectional and non-uniform compression of the false roof by the fractured surrounding rock. The loading direction is difficult to always be perpendicular to the surface of the false roof, which easily leads to eccentric loading. Second, the surrounding rock simulation layer mostly uses homogeneous materials, which cannot reproduce the real mechanical behavior such as random movement of rock blocks, force chain evolution, and local stress concentration in fractured surrounding rock. Third, the monitoring methods are mainly based on single-point sensors, which are difficult to obtain the fine distribution and dynamic evolution process of stress on the contact surface, and have limited ability to capture signs of instability.

[0004] Therefore, it is necessary to provide a stability simulation and monitoring device for the contact surface between the false roof and the surrounding rock based on intelligent sensors to solve the problems mentioned in the background art. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: a simulation and monitoring device for the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors, comprising a reaction frame, a flexible loading module, a composite surrounding rock simulation layer, a false roof module, a lateral pressurization system, and an intelligent sensor network;

[0006] The reaction frame is provided with a top beam mechanism, which is composed of multiple horizontally arranged arc beams hinged together. Each arc beam is connected to the reaction frame through at least two lifting adjustment mechanisms, and the lifting adjustment mechanism has a self-locking function.

[0007] The flexible loading module includes multiple floating loading units. The top of each floating loading unit is connected to the bottom of the corresponding arc beam via a universal hinge, and the bottom is connected to a rigid pressure plate via a ball joint. The lower surface of the multiple rigid pressure plates is covered with an elastic pad layer.

[0008] The composite surrounding rock simulation layer is disposed below the flexible loading module;

[0009] The false roof module is located below the composite surrounding rock simulation layer, and connecting ear plates are provided at its left and right ends respectively.

[0010] The lateral pressurization system includes symmetrically arranged side plate assemblies. Each side plate assembly includes an outer pressurization plate, an inner false top support, and a lateral hydraulic cylinder. One end of the lateral hydraulic cylinder is fixedly connected to the side column of the reaction frame, and the other end is connected to the outer pressurization plate. The outer pressurization plate is connected to the inner false top support through a linear floating mechanism. The inner false top support is provided with an embedding groove for accommodating the false top module and connecting ear plate.

[0011] The intelligent sensor network includes a thin-film pressure sensor array embedded on the upper surface of the false roof module, a fiber optic strain sensor embedded inside the false roof module, a laser displacement sensor installed on the reaction frame, a first displacement sensor bridging the false roof module and the composite surrounding rock simulation layer, an acoustic emission sensor installed around the composite surrounding rock simulation layer, and a first pressure sensor on the sidewall of the embedded groove.

[0012] Preferably, the composite surrounding rock simulation layer is composed of multiple stacked modular units, each modular unit is composed of multiple independent modules spliced ​​together, and two adjacent independent modules are connected by fracture-resistant connecting columns made of brittle material. Each independent module is filled with an elastic matrix and multiple irregular blocks dispersed in the elastic matrix.

[0013] Preferably, the composite surrounding rock simulation layer includes an upper module, a middle module, and a lower module, wherein the size or volume fraction of the irregular blocks filling the three modules decreases sequentially from top to bottom, and the elastic matrix in the lower module is a transparent polyurethane material.

[0014] Preferably, the floating loading unit further includes a second displacement sensor built into its hydraulic cylinder and a second pressure sensor array installed inside the rigid pressure plate, the rotation angle range of the universal hinge is ±8°, and the rotation angle range of the ball joint is ±5°.

[0015] Preferably, the dummy top module includes a surface wear-resistant layer, a flexible circuit board layer, and a dummy top substrate arranged sequentially from top to bottom. The thin-film pressure sensor array is printed on the lower surface of the flexible circuit board layer, and a signal lead-out line is provided on the upper surface of the flexible circuit board layer. The signal lead-out line converges to the signal lead-out interface at the edge of the dummy top module.

[0016] Preferably, the front side of the reaction frame is provided with a front plate made of transparent material, and the rear side of the reaction frame is provided with a rear plate, which is a steel plate or may optionally be equipped with an axial pressure mechanism.

[0017] Preferably, multiple adjusting rods are slidably provided on the left and right sides of the arc-shaped beam via hydraulic drive. Two adjusting rods at corresponding positions between two adjacent arc-shaped beams are rotatably connected to form an adjusting rod group, and the rotatable connection points between multiple adjusting rod groups are rotatably connected to a fixed support rod.

[0018] Preferably, the linear floating mechanism allows the inner false top support to have a horizontal floating displacement of ±5mm relative to the outer pressure plate.

[0019] Preferably, the inner false top support is provided with a connecting pin drive mechanism that can move in the vertical direction. The connecting pin drive mechanism is equipped with multiple connecting pins. The connecting ear plate is provided with multiple positioning holes corresponding to the connecting pins. The connecting pin drive mechanism drives the connecting pins to be inserted into the positioning holes and locks them after connection.

[0020] Preferably, it also includes a data acquisition unit, which is electrically connected to the thin-film pressure sensor array, fiber optic strain sensor, laser displacement sensor, first displacement sensor, acoustic emission sensor, first pressure sensor, second pressure sensor array and second displacement sensor, and is used to synchronously acquire signals from each sensor.

[0021] Compared with the prior art, the present invention provides a simulation and monitoring device for the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors, which has the following beneficial effects:

[0022] First, it realistically simulates the behavior of fractured surrounding rock: the self-organized movement, force chain evolution, and local instability of the blocks in the composite surrounding rock simulation layer under pressure are highly consistent with the mechanical behavior of real fractured surrounding rock, and the pressure distribution cloud map can display random point contact and dynamic changes.

[0023] Second, high-resolution contact surface monitoring: The thin-film pressure sensor array can successfully capture the contact imprint between a single irregular block and the dummy top. The pressure distribution cloud map clearly shows the location, size and pressure value of each contact point, thus providing unprecedented data support for studying the instability mechanism of the contact surface.

[0024] Third, multi-directional adaptive loading: The adjustable top beam mechanism, together with the universal hinge and ball joint of the floating loading unit, ensures that the force direction of multiple loading units is always perpendicular to the false top surface. Even if the false top deforms, the passive swing of the bottom ball joint and the top universal hinge allows the hydraulic cylinder to automatically adjust its posture and avoid uneven loading.

[0025] Fourth, lateral constraint and end monitoring: The zonal control of the lateral pressurization system realistically simulates the change of horizontal stress in the surrounding rock with depth. The connecting pin of the false roof connection module not only reliably fixes the false roof, but also monitors the end force in real time through the second pressure sensor, revealing the force evolution law of the false roof end during the failure process.

[0026] Fifth, multi-physics field collaborative early warning: the analysis algorithm that integrates multi-source data such as thin film pressure, fiber strain, displacement, and acoustic emission issues an early warning 30 seconds before the false top fails. The simultaneous anomalies in three indicators, namely pressure concentration factor, acoustic emission event rate, and delamination rate, further verify the reliability of multi-parameter fusion early warning. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the experimental process of the present invention;

[0028] Figure 2 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 3 This is a schematic diagram of the internal structure of the reaction frame in this invention;

[0030] Figure 4 This is a schematic diagram of the external structure of the reaction frame in this invention;

[0031] Figure 5 This is a schematic diagram of the top beam mechanism in this invention;

[0032] Figure 6 This is a schematic diagram of the structure of the false top module in this invention;

[0033] Figure 7 This is a schematic diagram of the inner false top support in this invention;

[0034] Figure 8 This is a schematic diagram of the internal structure of an independent module in this invention;

[0035] In the diagram: 1. Reaction frame; 11. Front side plate; 12. Rear side plate; 2. Flexible loading module; 21. Floating loading unit; 22. Rigid pressure plate; 23. Elastic pad layer; 3. Composite surrounding rock simulation layer; 31. Independent module; 32. Irregular block; 33. Upper module; 34. Middle module; 35. Lower module; 4. False roof module; 41. Connecting ear plate; 411. Positioning hole; 42. Surface wear-resistant layer; 43. Flexible circuit board layer; 44. False roof base plate; 5. Top beam mechanism; 51. Arc beam; 52. Lifting and adjusting mechanism; 53. Adjusting rod; 54. Fixed support rod; 6. Side plate assembly; 61. Outer pressure plate; 62. Inner false roof support; 621. Embedded groove; 622. Connecting pin; 63. Lateral hydraulic cylinder. Detailed Implementation

[0036] Please see Figures 1 to 8 In this embodiment of the invention, the stability simulation and monitoring device for the contact surface between the false roof and the surrounding rock based on intelligent sensors includes a reaction frame 1, a flexible loading module 2, a composite surrounding rock simulation layer 3, a false roof module 4, a lateral pressurization system, and an intelligent sensor network.

[0037] The reaction frame 1 is a welded rigid structure with a top beam mechanism 5. The top beam mechanism 5 is composed of multiple horizontally arranged arc beams 51 hinged together. Each arc beam 51 is connected to the reaction frame 1 through at least two lifting adjustment mechanisms 52 (three lifting adjustment mechanisms 52 are used in this scheme). The lifting adjustment mechanism 52 has a self-locking function. Specifically, the lifting adjustment mechanism can be operated to adjust the top beam mechanism 5 according to the arch curvature of the target false ceiling, so that the height of the multiple arc beams 51 can be precisely adjusted to the preset position, so that the line connecting the lower surfaces of each arc beam can form an arched surface that fits the false ceiling.

[0038] The flexible loading module 2 includes multiple floating loading units 21. The top of each floating loading unit 21 is connected to the lower part of the corresponding arc beam 51 via a universal hinge, and the bottom is connected to a rigid pressure plate 22 via a ball joint. The lower surface of the multiple rigid pressure plates 22 is covered with an elastic pad layer 23.

[0039] The composite surrounding rock simulation layer 3 is disposed below the flexible loading module 2 and is used to simulate the fractured surrounding rock above the false roof;

[0040] The false roof module 4 is located below the composite surrounding rock simulation layer 3 and is used to simulate a reinforced concrete false roof. Its preparation process is as follows: First, a flexible circuit board layer 43 is made. On the polyimide flexible substrate, a thin film pressure sensor array with a grid spacing of 5 mm is prepared by printing process. Signal lead-out lines are printed on the upper surface of the flexible circuit board layer 43 and converge to the pin micro signal lead-out interface at the edge of the module. Second, galvanized iron wire mesh is placed in the mold, and micro-particle concrete is poured to form a false roof substrate 44. Fiber grating strain sensors are pre-embedded inside the substrate to monitor the strain distribution inside the false roof. Finally, the flexible circuit board layer 43 and a 0.3 mm thick polyurethane surface wear-resistant layer 42 are sequentially laid on the upper surface of the false roof substrate 44 to form a complete false roof module 4. Connecting ear plates 41 are respectively provided at the left and right ends of the false roof module 4.

[0041] The lateral pressurization system includes side plate assemblies 6 arranged symmetrically on the left and right. Each side plate assembly 6 includes an outer pressurization plate 61, an inner false top support 62, and a lateral hydraulic cylinder 63. One end of the lateral hydraulic cylinder 63 is fixedly connected to the side column of the reaction frame 1, and the other end is connected to the outer pressurization plate 61. The outer pressurization plate 61 is connected to the inner false top support 62 through a linear floating mechanism. The inner false top support 62 is provided with an embedding groove 621 for accommodating the false top module 4 and the connecting ear plate 41.

[0042] The inner false top support 62 is provided with a connecting pin drive mechanism that can move in the vertical direction. Multiple connecting pins 622 are installed on the connecting pin drive mechanism. Multiple positioning holes 411 corresponding to the connecting pins 622 are opened on the connecting ear plate 41. The connecting pin drive mechanism drives the connecting pins 622 to be inserted into the positioning holes 411 and locked after connection.

[0043] The intelligent sensor network includes a thin-film pressure sensor array embedded on the upper surface of the false roof module 4, a fiber optic strain sensor embedded inside the false roof module 4, a laser displacement sensor installed on the reaction frame 1, a first displacement sensor bridging the false roof module 4 and the composite surrounding rock simulation layer 3, an acoustic emission sensor installed around the composite surrounding rock simulation layer 3, and a first pressure sensor on the side wall of the embedded groove 621.

[0044] In this embodiment, the composite surrounding rock simulation layer 3 is composed of multiple stacked modular units. Each modular unit is composed of multiple independent modules 31 spliced ​​together. Adjacent independent modules 31 are connected by fracture-resistant connecting columns made of brittle material. Each independent module 31 is filled with an elastic matrix and multiple irregular blocks 32 dispersed in the elastic matrix.

[0045] In this embodiment, the composite surrounding rock simulation layer 3 includes an upper module 33, a middle module 34, and a lower module 35. The size or volume fraction of the irregular blocks 32 filling the three layers decreases from top to bottom, and the elastic matrix in the lower module 35 is a transparent polyurethane material.

[0046] Furthermore, the elastic matrix of the upper module 33 is Shore A60 polyurethane, and the irregular rigid blocks 32 are made of tungsten steel, with dimensions of 20-40 mm and a volume fraction of 60%. The modules are connected by brittle nylon pillars (breakable connecting pillars) to simulate a direct-top layered structure. The elastic matrix of the middle module 34 is Shore A50 polyurethane, with block dimensions of 10-30 mm and a volume fraction of 45%. There are no special connections between the modules. The elastic matrix of the lower module 35 is transparent polyurethane (Shore A40), and the blocks are made of steel balls (with fluorescent markings sprayed on the surface), with dimensions of 5-20 mm and a volume fraction of 30%. The movement of the blocks is observed through a bottom camera system. Each block 32 can be embedded with a miniature permanent magnet for resetting after the test. During installation, the prefabricated lower-layer modules 35 are hoisted one by one onto the false top module 4. They can be fixed by positioning pins at the four corners of the modules and magnetic adsorption. The middle-layer module 34 and the upper-layer module 33 are installed in the same way. During the installation process, it is necessary to ensure that the upper and lower-layer modules are staggered to simulate the cross-bedding of real rock strata. After installation, its lower surface is in close contact with the upper surface of the false top module 4, and its upper surface is in contact with the elastic pad 23 of the flexible loading module 2, forming a complete force transmission path.

[0047] In this embodiment, the floating loading unit 21 further includes a second displacement sensor built into its hydraulic cylinder and a second pressure sensor array installed inside the rigid pressure plate 22. The rotation angle range of the universal hinge is ±8° and the rotation angle range of the ball joint is ±5°.

[0048] In this embodiment, the dummy top module 4 includes a surface wear-resistant layer 42, a flexible circuit board layer 43, and a dummy top substrate 44 arranged sequentially from top to bottom. The thin film pressure sensor array is printed on the lower surface of the flexible circuit board layer 43, and a signal lead-out line is provided on the upper surface of the flexible circuit board layer 43. The signal lead-out line converges to the signal lead-out interface at the edge of the dummy top module 4.

[0049] In this embodiment, a front side plate 11 made of transparent material is provided on the front side of the reaction frame 1, and a rear side plate 12 is provided on the rear side of the reaction frame 1. The rear side plate 12 is a steel plate or may be optionally equipped with an axial pressure mechanism.

[0050] In this embodiment, multiple adjusting rods 53 are hydraulically driven and slidably arranged on the left and right sides of the arc beam 51. Two adjusting rods 53 at corresponding positions between two adjacent arc beams 51 are rotatably connected to form an adjusting rod group, and the rotatable connection points between multiple adjusting rod groups are rotatably connected to a fixed support rod 54.

[0051] In particular, to ensure the synchronicity, stability, and rigidity of each arc beam 51 in the adjustment mechanism, two adjacent arc beams 51 are connected by multiple adjustment rod groups. The height of the arc beams 51 is controlled by the lifting adjustment mechanism 52. The relative position between two adjacent arc beams 51 is further controlled by the adjustment rod group 53 and the fixed support rod 54. This allows the adjusted arc beams 51 to be fixed, forming a loading base and providing stable support for the flexible loading module 2.

[0052] In this embodiment, the linear floating mechanism allows the inner false top support 62 to have a horizontal floating displacement of ±5mm relative to the outer pressure plate 61 to accommodate model deformation.

[0053] In this embodiment, a data acquisition unit is also included. The data acquisition unit is electrically connected to the thin-film pressure sensor array, fiber optic strain sensor, laser displacement sensor, first displacement sensor, acoustic emission sensor, first pressure sensor, second pressure sensor array, and second displacement sensor. It is used to synchronously acquire signals from each sensor.

[0054] During implementation, the prefabricated false roof module 4 is hoisted onto an independent false roof mounting frame (not shown in the figure). The mounting frame is used to push the false roof module 4 into the reaction frame 1. Using a laser positioning system, the false roof module 4 is precisely adjusted to the design position. After adjustment, the lateral pressurization system is activated, and the false roof support 62 in the side plate assembly 6 slides to the bottom of the false roof module 4, while aligning the connecting ear plate 41 with the embedding groove 621. Then, the connecting pin drive mechanism is used to push multiple connecting pins 622 to slide, so that they are precisely inserted into the positioning holes 411 on the connecting ear plate 41. Then, the connecting pins 622 are locked, the false roof mounting frame releases the false roof module 4 and moves out of the reaction frame. At this time, the false roof module 4 is supported by the side plate assemblies 6 on both sides. Then, in the order of lower layer, middle layer and upper layer, the prefabricated modular units are stacked layer by layer on the false roof module 4 by hoisting equipment. Each layer of independent modules 31 can be reinforced by positioning pins and magnetic adsorption.

[0055] After stacking is completed, based on the measured ground stress data of the mining area, the loading scheme is as follows:

[0056] Vertical pressure: applied through flexible loading module 2, with a target pressure of 2.0 MPa for the floating loading unit in the arch crown area; 1.5 MPa for the floating loading unit in the arch shoulder area; and 1.0 MPa for the floating loading unit in the side wall area (corresponding to the top area of ​​the composite layer).

[0057] Horizontal pressure: applied through a lateral pressurization system. Side plate assembly 6 can also be applied in layers: 1.2 MPa is applied to the middle zone to simulate the horizontal stress in the false roof area; 0.8 MPa is applied to the lower zone to simulate the roadway sidewall constraint; and 0.5 MPa is applied to the upper zone to simulate the shallow horizontal stress.

[0058] All floating loading units 21 are synchronously loaded to the target pressure and kept constant. During the loading process, the universal hinges and ball joints of the floating loading units 21 can be automatically fine-tuned according to the deformation of the model to ensure that the rigid pressure plate 22 always applies pressure vertically and uniformly downward through the elastic pad layer 23. The linear floating mechanism 64 between the outer pressure plate 61 and the inner false top support 62 allows a floating of ±5mm to adapt to the lateral deformation of the composite surrounding rock simulation layer 3 after being compressed.

[0059] Experimental phenomena and data recording:

[0060] Initial stage: The thin-film pressure sensor array shows a uniform pressure distribution on the surface of the false roof, and the acoustic emission sensor records sporadic low-energy events, corresponding to minor adjustments of the blocks inside the composite layer; Pressure increase stage: The vertical pressure in the arch area is gradually increased to 3.5 MPa at a rate of 0.1 MPa / 10 min. At this time, the pressure distribution cloud map begins to show significant changes: local areas show high stress concentration points with pressure values ​​reaching 1.8 times the average value. These points slowly move and merge over time; In the lower transparent module 35, the irregular blocks 32 can be observed to rotate and displace, and some irregular blocks 32 are pressed downward, forming moving "contact imprints" on the surface of the false roof; The acoustic emission event rate and energy increase significantly, and the event localization shows that they are concentrated near the high-stress area; The fiber optic strain sensor detects an increase in tensile strain inside the false roof, mainly distributed in the area between the two high-stress concentration areas, and the first pressure on the sidewall of the embedded groove 621. Sensors detected a gradual increase in pressure at the top of the false roof, indicating that the false roof began to bear and transfer some horizontal force to the side plates. Near failure stage: When the pressure at the top of the arch increased to 4.0 MPa, the brittle nylon column 311 between the upper modules 33 of the composite surrounding rock simulation layer 3 fractured, accompanied by a significant acoustic emission signal. The pressure distribution cloud map fluctuated violently, a major stress concentration zone rapidly expanded, and the pressure peak reached 2.5 times the average value. The first displacement sensor detected that the delamination between the false roof and the composite layer began to accelerate. The analysis software built into the data acquisition unit triggered an "early warning" state based on characteristic parameters such as the pressure concentration coefficient, delamination rate, and acoustic emission b-value. Failure stage: Loading continued to 4.2 MPa, and the false roof module 4 suddenly failed, accompanied by a loud sound and instantaneous pressure release. The high-speed camera system recorded that longitudinal cracks originated from the top of the false roof and extended to both sides. All sensor data showed a step change.

[0061] After the test, stop pressurizing the flexible loading module 2, reset the flexible loading module, and disassemble the composite surrounding rock simulation layer 3 and the false roof module 4 in the reverse order of installation.

[0062] Through the above-described specific experimental process, the present invention has produced the following beneficial effects:

[0063] 1) It realistically reproduces the discontinuous and non-uniform mechanical behavior of fractured surrounding rock: Unlike traditional homogeneous surrounding rock simulation materials, the composite surrounding rock simulation layer 3 of this invention exhibits self-organizing behaviors such as movement, rotation, and mutual compression of the irregular blocks 32 inside under pressure. This is directly reflected in the dynamically changing pressure distribution cloud map recorded by the thin-film pressure sensor array—discrete, moving, and merging stress concentration points appear, perfectly simulating the point contact and local impact of real fractured rock mass on the false ceiling.

[0064] 2) Achieved ultra-high resolution monitoring of stress distribution at the contact surface between the false roof and the surrounding rock: By directly embedding a thin-film pressure sensor array on the surface of the false roof module 4, it successfully captured the "pressure imprint" generated by the contact between a single irregular block 32 and the false roof. This enabled researchers to delve into the study of "microscopic contact mechanism" from "macroscopic pressure distribution", providing key data for revealing the initiation, development and connection mechanism of instability at the contact surface.

[0065] 3) Verified the reliability and accuracy of the adaptive loading system: During the loading process, the adjustable top beam mechanism 5 pre-forms an arched surface consistent with the dummy top. Each floating loading unit 21 of the flexible loading module 2 automatically adjusts its posture when the model deforms through the universal hinge at the top and the ball joint at the bottom, ensuring that the thrust is always perpendicular to the local surface of the dummy top. This avoids stress concentration and premature model failure caused by eccentric loading in traditional rigid loading, ensuring the accuracy of loading. At the same time, the second pressure sensor array built into the rigid pressure plate 22 monitors the loading force of each unit in real time, forming a precise closed-loop control.

[0066] 4) Demonstrates a realistic simulation of the constraint of the false top by the lateral pressurization system: The lateral pressurization system of the present invention realizes a fine simulation of the embedded state of the false top through the setting of the embedding groove 621 and the connecting pin 622. The first pressure sensor on the side wall of the embedding groove 621 realizes the direct measurement of the force on the false top. The process of the end pressure changing with the deflection of the false top monitored in the experiment provides a new perspective for studying the interaction between the false top and the surrounding rock.

[0067] 5) Demonstrated the feasibility of multi-source information fusion and early warning: The data acquisition device simultaneously collected massive amounts of multi-physics field data, including pressure distribution, strain, displacement, and acoustic emission. Based on this data, the analysis software extracted characteristic parameters such as pressure concentration coefficient, delamination rate, acoustic emission event rate, and b-value. Before the false roof failed, the comprehensive trend of these parameters successfully triggered an "early warning" signal, providing a new technical means for underground engineering safety monitoring.

[0068] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A device for simulating and monitoring the stability of the contact surface between a false roof and surrounding rock based on intelligent sensors, characterized in that, It includes a reaction frame (1), a flexible loading module (2), a composite surrounding rock simulation layer (3), a false roof module (4), a lateral pressurization system, and an intelligent sensor network; The top of the reaction frame (1) is provided with a top beam mechanism (5), which is composed of multiple horizontally arranged arc beams (51) hinged together. Each arc beam (51) is connected to the reaction frame (1) through at least two lifting adjustment mechanisms (52), and the lifting adjustment mechanism (52) has a self-locking function. The flexible loading module (2) includes multiple floating loading units (21). The top of each floating loading unit (21) is connected to the bottom of the corresponding arc beam (51) via a universal hinge, and the bottom is connected to a rigid pressure plate (22) via a ball joint. The lower surface of the multiple rigid pressure plates (22) is covered with an elastic pad layer (23). The composite surrounding rock simulation layer (3) is disposed below the flexible loading module (2); The false roof module (4) is located below the composite surrounding rock simulation layer (3), and connecting ear plates (41) are provided at its left and right ends respectively; The lateral pressurization system includes side plate assemblies (6) arranged symmetrically on the left and right. Each side plate assembly (6) includes an outer pressurization plate (61), an inner false top support (62), and a lateral hydraulic cylinder (63). One end of the lateral hydraulic cylinder (63) is fixedly connected to the side column of the reaction frame (1), and the other end is connected to the outer pressurization plate (61). The outer pressurization plate (61) is connected to the inner false top support (62) through a linear floating mechanism. The inner false top support (62) is provided with an embedding groove (621) for accommodating the false top module (4) and the connecting ear plate (41). The intelligent sensor network includes a thin-film pressure sensor array embedded on the upper surface of the false roof module (4), a fiber optic strain sensor embedded inside the false roof module (4), a laser displacement sensor installed on the reaction frame (1), a first displacement sensor bridging the false roof module (4) and the composite surrounding rock simulation layer (3), an acoustic emission sensor installed around the composite surrounding rock simulation layer (3), and a first pressure sensor on the side wall of the embedded groove (621).

2. The device for simulating and monitoring the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors according to claim 1, characterized in that, The composite surrounding rock simulation layer (3) is composed of multiple stacked modular units. Each modular unit is spliced ​​together from multiple independent modules (31). Adjacent independent modules (31) are connected by fracture-resistant connecting columns made of brittle material. Each independent module (31) is filled with an elastic matrix and multiple irregular blocks (32) dispersed in the elastic matrix.

3. The stability simulation and monitoring device for the contact surface between the false roof and surrounding rock based on intelligent sensors according to claim 2, characterized in that, The composite surrounding rock simulation layer (3) includes an upper module (33), a middle module (34) and a lower module (35). The size or volume fraction of the irregular blocks (32) filling the three layers decreases from top to bottom, and the elastic matrix in the lower module (35) is a transparent polyurethane material.

4. The device for simulating and monitoring the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors according to claim 1, characterized in that, The floating loading unit (21) also includes a second displacement sensor built into its hydraulic cylinder and a second pressure sensor array installed inside the rigid pressure plate (22). The rotation angle range of the universal hinge is ±8° and the rotation angle range of the ball joint is ±5°.

5. The device for simulating and monitoring the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors according to claim 1, characterized in that, The dummy top module (4) includes a surface wear-resistant layer (42), a flexible circuit board layer (43), and a dummy top substrate (44) arranged sequentially from top to bottom. The thin film pressure sensor array is printed on the lower surface of the flexible circuit board layer (43). The upper surface of the flexible circuit board layer (43) is provided with signal lead-out lines, which converge to the signal lead-out interface at the edge of the dummy top module (4).

6. The device for simulating and monitoring the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors according to claim 1, characterized in that, The front side of the reaction frame (1) is provided with a front side plate (11) made of transparent material, and the rear side of the reaction frame (1) is provided with a rear side plate (12). The rear side plate (12) is a steel plate or may be optionally equipped with an axial pressure mechanism.

7. The device for simulating and monitoring the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors according to claim 1, characterized in that, Multiple adjusting rods (53) are hydraulically driven to slide on both sides of the arc beam (51). Two adjusting rods (53) at corresponding positions between two adjacent arc beams (51) are rotatably connected to form an adjusting rod group, and the rotatable connection points between multiple adjusting rod groups are rotatably connected to a fixed support rod (54).

8. The device for simulating and monitoring the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors according to claim 1, characterized in that, The linear floating mechanism allows the inner false top support (62) to have a horizontal floating displacement of ±5 mm relative to the outer pressure plate (61).

9. The device for simulating and monitoring the stability of the contact surface between the false roof and the surrounding rock based on intelligent sensors according to claim 1, characterized in that, The inner false top support (62) is provided with a connecting pin drive mechanism that can move in the vertical direction. The connecting pin drive mechanism is equipped with a plurality of connecting pins (622). The connecting ear plate (41) is provided with a plurality of positioning holes (411) corresponding to the connecting pins (622). The connecting pin drive mechanism drives the connecting pins (622) to be inserted into the positioning holes (411) and locked after connection.

10. The stability simulation and monitoring device for the contact surface between the false roof and surrounding rock based on intelligent sensors according to claim 4, characterized in that, It also includes a data acquisition unit, which is electrically connected to the thin-film pressure sensor array, fiber optic strain sensor, laser displacement sensor, first displacement sensor, acoustic emission sensor, first pressure sensor, second pressure sensor array and second displacement sensor, and is used to synchronously acquire signals from each sensor.

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