A multi-element dynamic testing device and method under a thick loose layer

Abstract

The application discloses a kind of multivariate dynamic test device and test method under thick loose layer, belong to the technical field of physical simulation of mine exploitation.The device includes main frame, loose layer migration monitoring module, water inrush simulation module, rock burst simulation module and total control module.Water inrush simulation module includes roof water disaster simulation module and floor water disaster simulation module to realize controllable water inrush simulation;Rock burst simulation module realizes roadway local fracture and large deformation simulation through movable air bag energy release assembly and segmented striker trigger assembly.The application can simulate the multivariate dynamic disaster chain evolution process of loose layer migration, roof and floor water inrush, rock burst and roadway instability induced by mining under thick loose layer in the same test platform, and provides test support for deep coal mine multivariate dynamic disaster collaborative prevention and control.

Description

Technical Field

[0001] This application relates to the field of physical simulation technology for mining operations, and in particular to a multi-element dynamic test device and test method for a thick loose layer. Background Technology

[0002] Deep coal resources are important reserve coal resources. With the continuous increase in mining depth and scale, multi-energy-related disasters in coal mines have become a prominent problem restricting the safe and efficient production of deep coal resources. In some mining areas in my country, a special stratigraphic structure generally exists above the main coal seam, consisting of a thick loose layer and underlying weak bedrock. The underlying bedrock has low strength, poor stability, and well-developed fissures. During the mining process, the fracturing and movement of the weak bedrock causes large-scale displacement of the overlying loose layer, and the water-conducting fissures in the roof and floor continue to expand. Once the roof aquifer and the floor confined aquifer within the loose layer form a local connection, it is very easy to induce roof water inrush or floor confined water inrush. At the same time, the continuous intrusion of water causes the stress field of the surrounding rock in the roadway to redistribute and local stress concentration, which may further induce rockburst and roadway instability and deformation. More importantly, the migration of loose layers, the propagation of water-conducting fractures, the inrush of water to the top and bottom plates, and the shock instability are not independent of each other, but rather there is a complex coupling relationship of temporal transmission, mutual influence and mutual feedback. The development of any one of the disaster links may promote the triggering and expansion of other disasters.

[0003] Most existing experimental devices are designed around single disaster responses, typically simulating only one aspect of overburden collapse, localized seepage, or a single dynamic impact. They struggle to simultaneously reflect the continuous evolution of large-scale loose layer migration, roof and floor water hazard evolution, rockburst, and surface subsidence under conditions of thick loose layers within a single experimental platform. This makes it impossible to achieve coordinated simulation and full-process monitoring of multiple dynamic disasters. Therefore, there is an urgent need for a method applicable to conditions of thick loose layers to reveal the gestation, triggering, expansion, and coupled evolution of multiple disasters, providing experimental support for the coordinated prevention and control of multiple dynamic disasters in deep coal mines. Summary of the Invention

[0004] This application provides a multi-element dynamic test device and test method under a thick loose layer. Its purpose is to simulate dynamic disaster test device for large-scale movement of loose layer, water hazard of roof and floor, rock burst and roadway instability response on the same test platform.

[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application provides a multi-element dynamic testing device under a very thick loose layer, comprising: The main framework is used to provide the model filling space and boundary constraints; The loose layer migration monitoring module is installed on the main frame, with its monitoring end extending into the interior of the main frame. It is used to continuously monitor the settlement, slippage, and surface subsidence characteristics of the thick loose layer under mining disturbance. A water inrush simulation module is installed inside the main frame to simulate the water inrush process of the top plate water and the bottom plate pressurized water under the condition of crack penetration. The water inrush simulation module includes a top plate water damage simulation module and a bottom plate water damage simulation module. The rockburst simulation module is installed in the roadway surrounding rock simulation structure inside the main frame. It is used to simulate the rupture, instability and large deformation of the roadway surrounding rock under the coupling effect of stress concentration and transient energy release. The main control module is electrically connected to the loose layer migration monitoring module, the water inrush simulation module, and the rockburst simulation module, respectively, and is used to perform coordinated control, trigger determination, and full-process data acquisition for each module.

[0006] Furthermore, the main frame is a detachable rectangular frame, including a left side plate and a right side plate; the left side plate is provided with a sealed pipe passage, and the right side plate is provided with a sealed operation passage.

[0007] Furthermore, the roof flooding simulation module includes: The roof water storage triggering component is set at the bottom of the pre-set aquifer or loose layer of the roof near the bedrock interface. It adopts a flat water storage structure with a flexible membrane and is equipped with a water injection interface that connects to an external water source. The top and bottom plate water supply assembly is connected to the top plate water storage trigger assembly and is used to inject water into the flat water storage structure; A top plate crack triggering component is disposed at the bottom or side of the flat water storage structure and is used to trigger the water storage structure to rupture and form a crack when the mining crack expands to a preset position.

[0008] Furthermore, the bottom plate water damage simulation module includes: The base plate pressurized water tank is set at the bottom of the filled space within the main frame; A bottom plate crack triggering membrane assembly is disposed between the bottom plate pressurized water tank and the upper filling layer; The base plate pressurization spray assembly is connected to the base plate pressurized water tank and is used to pressurize and supply water to the base plate pressurized water tank.

[0009] Furthermore, the rockburst simulation module includes: The simulated structure of the surrounding rock in the tunnel has an outer constrained layer and an inner brittle layer; A mobile airbag energy release assembly is installed inside the tunnel and connected to an external air supply assembly; The segmented impact pin trigger assembly is disposed on the inner side of the inner brittle layer and is used to break the segment of the inner brittle layer when the airbag releases energy. The airbag retraction and positioning component is connected to the mobile airbag energy release component, and is used to retract and position it synchronously along the roadway axis with the mining advance direction.

[0010] Furthermore, the rockburst simulation module also includes a stress sensor, which is located on the outside of the roadway and electrically connected to an external stress monitoring receiver.

[0011] Furthermore, the main control module is electrically connected to the signal receiving component and the data acquisition component, and is used to coordinate the control of the water inrush simulation module and the rockburst simulation module, and to synchronously record and analyze the data collected by each monitoring module.

[0012] Furthermore, the flat water storage structure of the top plate water storage trigger component has heterogeneous water distribution characteristics.

[0013] Furthermore, the top plate crack triggering assembly includes a thermal triggering unit and a sensing unit. The sensing unit is used to send a signal when the mining crack expands to a preset position, and the thermal triggering unit is used to heat the water storage structure to form a crack.

[0014] Secondly, this application provides a test method based on the multi-element dynamic test device under a thick loose layer described in the first aspect, the test method comprising the following steps: Step 1: Based on the geological conditions and disaster research requirements of the target mine, determine the geometric dimensions, similarity ratio, mining propulsion scheme and water supply parameters of the similar model, and complete the installation and initial status check of each module of the device; Step 2: Lay the bottom layer, coal seam, bedrock layer, loose layer and surface layer of similar materials in sequence from bottom to top. After each layer is laid, compaction is carried out. At the same time, roadway simulation structure, roof water storage structure, bottom water storage structure, triggering element and monitoring element are arranged in the corresponding layers. After the model is built, it is cured. Step 3: Inject a predetermined amount of water into the top plate water storage trigger component and the bottom plate pressurized water tank respectively, and adjust the water injection pressure and pressurization conditions to form simulated hydrological conditions; Step 4: Advance the mining of the working face according to the predetermined mining sequence to induce overburden fracturing, fracture evolution and loose layer migration, while continuously acquiring migration information through the loose layer migration monitoring module; Step 5: When the overlying rock fissures extend to the preset layer, trigger the top plate water storage triggering component or the bottom plate fissure triggering membrane component to release the water in the water storage structure, simulate the top plate water inrush or bottom plate pressure water inrush process, and record the water inrush location and timing. Step 6: When the stress of the surrounding rock in the roadway reaches the preset triggering condition, the rockburst simulation module is activated, causing the mobile airbag energy release component to retract to the target roadway section. The airbag is controlled to inflate rapidly and then deflate instantaneously, driving the segmented striker trigger component to break the inner brittle layer of that section, simulating local rupture and large deformation of the roadway. Step 7: Throughout the entire experiment, the main control module synchronously collects and comprehensively analyzes information on loose layer migration, fracture propagation, water inrush, changes in surrounding rock stress, and impact instability to obtain the spatiotemporal evolution process of the multi-dynamic disaster chain.

[0015] The beneficial effects of this invention are: This invention enables large-scale migration of loose layers induced by mining under thick loose layers within the same similar simulation test platform, thereby simulating the entire process of multi-dynamic disaster chains such as roof water inrush, floor water inrush, and rock bursts. It overcomes the shortcomings of existing test devices in continuously reflecting the migration of loose layers, fracture propagation, water inrush, and the evolution of shock instability within a unified platform.

[0016] This invention constructs an experimental device for top and bottom plate water inrush, and integrates water storage, triggering and monitoring functions. It can controllably simulate the location, timing and process of water inrush according to experimental requirements, and realize real-time monitoring of relevant parameters of the water inrush process.

[0017] This invention can effectively monitor the migration process of thick loose layers under mining operations, and can obtain dynamic response characteristics such as loose layer settlement, slippage and surface subsidence.

[0018] This invention can simulate the stress failure characteristics and large deformation process of the surrounding rock in a roadway during a rockburst, and can more realistically reflect the instability evolution law of the surrounding rock under rockburst disturbance conditions. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the exploded structure of a multi-element dynamic test device under a very thick loose layer; Figure 2 This is a schematic diagram of the simulated working mode of a multi-element dynamic test device under a very thick loose layer; Figure 3 This is a schematic diagram of the main framework structure; Figure 4 This is a schematic diagram of the top and bottom water supply components. Figure 5 This is a schematic diagram of the top plate water storage trigger component structure; Figure 6 This is a schematic diagram of the top plate crack triggering component structure; Figure 7 This is a schematic diagram of the displacement marker and signal receiving component. Figure 8This is a schematic diagram of the bottom plate water damage simulation module structure; Figure 9 This is a schematic diagram of a three-section tunnel surrounding rock simulation structure; Figure 10 This is a schematic diagram of the segmented firing pin trigger component structure; Figure 11 This is a schematic diagram of the structure of the mobile airbag energy release component.

[0020] As shown in the figure: 1. Main frame; 2. Base; 3. Base plate; 4. Left side plate; 5. Right side plate; 6. Top beam; 7. Upper loading hydraulic plate; 71. Hydraulic cylinder; 8. Loose layer movement monitoring module; 9. Displacement marker; 10. Top plate water storage trigger assembly; 11. Top plate crack trigger assembly; 12. Upper membrane layer; 13. Lower membrane layer; 14. Water injection interface; 15. Constant pressure water tank; 16. Pneumatic booster pump; 17. One-way valve; 18. Water delivery hose; 19. Pressure tank on the base plate; 20. Base plate crack triggering membrane assembly; 201. Porous bearing plate; 202. Intelligent diversion valve; 21. Mobile airbag energy release assembly; 211. Airbag; 212. Traction rope; 213. Flexible high-pressure air hose; 22. Segmented impact pin triggering assembly; 23. Airbag retraction positioning assembly; 24. Sensing unit; 241. Thermal triggering unit; 25. Stress sensor; 26. First tunnel section; 261. Second tunnel section; 262. Third tunnel section; 27. Inner brittle layer; 28. Removable front and rear panels; 29. ​​Drive motor; 30. Needle holder; 31. Strike pin; 32. Air impact plate; 33. Sealed conduit channel; 331. Miniature flow control unit; 34. Signal receiving component; 35. Data acquisition component; 36. Main control module. Detailed Implementation

[0021] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0022] Deep coal resources are important reserve coal resources. With the continuous increase in mining depth and scale, multi-energy-related disasters in coal mines have become a prominent problem restricting the safe and efficient production of deep coal resources. In some mining areas, a special stratigraphic structure generally exists above the main coal seam, consisting of a thick loose layer and underlying weak bedrock. The underlying bedrock has low strength, poor stability, and well-developed fissures. During the mining process, the fracturing and movement of the weak bedrock causes large-scale displacement of the overlying loose layer, and the water-conducting fissures in the roof and floor continue to expand. Once the roof aquifer and the floor confined aquifer within the loose layer form a local connection, it is very easy to induce roof water inrush or floor confined water inrush. At the same time, the continuous intrusion of water causes the stress field of the surrounding rock in the roadway to redistribute and local stress concentration, which may further induce rockburst and roadway instability and deformation. More importantly, the migration of loose layers, the propagation of water-conducting fractures, the inrush of water to the top and bottom plates, and the shock instability are not independent of each other, but rather there is a complex coupling relationship of temporal transmission, mutual influence and mutual feedback. The development of any one of the disaster links may promote the triggering and expansion of other disasters.

[0023] Most existing experimental devices are designed around single disaster responses, typically simulating only one aspect of overburden collapse, localized seepage, or a single dynamic impact. They struggle to simultaneously reflect the continuous evolution of large-scale loose layer migration, roof and floor water hazard evolution, rockburst, and surface subsidence under conditions of thick loose layers within a single experimental platform. This makes it impossible to achieve coordinated simulation and full-process monitoring of multiple dynamic disasters. Therefore, there is an urgent need for a method applicable to conditions of thick loose layers to reveal the gestation, triggering, expansion, and coupled evolution of multiple disasters, providing experimental support for the coordinated prevention and control of multiple dynamic disasters in deep coal mines.

[0024] Based on this, this application proposes a multi-dynamic experimental device and method under a thick loose layer. By integrating a main frame, a loose layer migration monitoring module, a water inrush simulation module including a roof water hazard simulation module and a floor water hazard simulation module, a rockburst simulation module, and a data acquisition and overall control module, and using the data acquisition and overall control module to perform coordinated control, trigger determination, and full-process data acquisition of each module, it realizes the continuous evolution simulation and synchronous monitoring of large-scale loose layer migration, roof / floor water inrush, rockburst, and roadway instability within the same experimental platform. This solves the problem that existing technologies are unable to coordinately simulate the continuous process and response of multi-dynamic disasters under thick loose layer conditions within the same platform.

[0025] In the following, embodiments of this application will be described in detail with reference to the accompanying drawings.

[0026] Reference Figures 1 to 11A multi-element dynamic testing device for a thick loose stratum includes a main frame 1, a loose stratum migration monitoring module 8, a water inrush simulation module, a rockburst simulation module, and a main control module. The main frame 1 provides space for model filling, boundary constraints, and the installation foundation for each functional component. The loose stratum migration monitoring module 8 monitors the migration characteristics of the thick loose stratum under mining disturbance. The water inrush simulation module simulates roof water damage and pressure-bearing water inrush in the floor slab. The rockburst simulation module simulates the local fracturing and large deformation response of the surrounding rock in the tunnel under disturbance conditions. The main control module provides unified control and recording of the operating status, triggering sequence, and monitoring data of each module. Through this structural arrangement, continuous evolution simulation of loose stratum migration, roof and floor water inrush, and rockburst instability under a thick loose stratum can be achieved within the same testing platform.

[0027] Specifically, the main frame 1 is a rectangular, detachable load-bearing structure, including a base 2, a bottom plate 3, a left side plate 4, a right side plate 5, a top beam 6, an upper loading hydraulic plate 7, and front and rear detachable enclosure plates 28. The interior of the main frame 1 is used for layered filling of coal seams, bedrock layers, loose layers, and similar materials to the roadway structure. At least one side of the front and rear enclosure plates can be equipped with a transparent observation plate to allow for visual observation of the test process.

[0028] The base plate 3 is fixedly installed on the upper surface of the base 2. The left side plate 4 and the right side plate 5 are respectively set on the left and right sides of the base plate 3. The top is connected by the top beam 6 to form a closed load-bearing space. The upper loading hydraulic plate 7 is set on the top of the main frame 1 and is used to compact the similar materials of each layer during the model construction process. The upper loading hydraulic plate 7 achieves force loading through the hydraulic cylinder 71. The front and rear sides of the main frame 1 are equipped with multi-section detachable enclosure panels. Each section of enclosure panel is connected to the main frame 1 by bolts so that the enclosure space can be gradually increased layer by layer during the layering of the model.

[0029] On the left side plate 4, several sealed pipe passages 33 are provided at the pipe access positions corresponding to the top and bottom plate water supply components. The water supply hose 18 passes through the sealed pipe passages 33 and connects to the top plate water storage trigger component 10 and the bottom plate pressure tank 19 inside the main frame 1. The outer periphery of the sealed pipe passages 33 is provided with sealing sleeves, compression rings or sealing fillers to ensure the sealing of the boundary of the main frame 1 and prevent water and grout leakage during the test. The sealed pipe passages 33 are also provided with multiple micro flow control units 331 to control the water supply to different areas inside the side plate.

[0030] A sealed operation channel is provided on the right side plate 5 corresponding to the tunnel simulation area. The sealed operation channel is used for the mobile airbag energy release component 21, flexible high-pressure air pipe 213 and traction rope 212 to pass into the main frame 1 and correspond to the tunnel simulation area, so as to realize the installation, inflation, deflation and retraction operation of the airbag 211.

[0031] The loose layer movement monitoring module 8 includes displacement markers 9, a signal receiving component 34, and a data acquisition component 35. The displacement markers 9 are arrayed and embedded in different layers inside the loose layer and at key positions on its surface, for transmitting preset electromagnetic signals. The signal receiving component 34 is fixedly positioned on the left side plate 4 of the main frame 1, for receiving signal change information from the displacement markers 9. The data acquisition component 35 is electrically connected to the signal receiving component 34, for calculating the displacement of each monitoring point based on signal changes.

[0032] The main control module 36 is electrically connected to the signal receiving component 34 and the data acquisition component 35. The data acquisition component 35 is fixed at the front end of the main frame 1 and is used to calculate and record the displacement, settlement, and interlayer relative displacement of each monitoring point during the test based on the relative position changes between each displacement marker 9 and the signal receiving component 34. When the lower goaf expands and causes the overlying rock structure to break and the loose layer to move, each displacement marker 9 moves synchronously with the loose layer medium, and the position of the corresponding signal received by the signal receiving component changes. Based on this, the data acquisition component 35 obtains the spatial position changes of each monitoring point, and then judges the degree of migration of different layers of the loose layer and the development characteristics of surface subsidence.

[0033] The water inrush simulation module includes a roof water hazard simulation module and a floor water hazard simulation module. The roof water hazard simulation module includes a roof water storage triggering component 10, a roof and floor water supply component, and a roof crack triggering component 11. The roof water storage triggering component 10 is located in a predetermined area near the bedrock interface at a preset aquifer or loose layer in the roof, and includes an upper membrane layer 12, a lower membrane layer 13, a surrounding sealing edge, and a water injection interface 14 communicating with an external water tank. The roof water storage triggering component 10 adopts a flat water storage structure with a flexible membrane, which has a small thickness and stiffness, and does not significantly restrict the normal movement of the overlying loose layer when not triggered. The flat water storage structure is equipped with a flexible thickness limiting component to maintain the basic water storage space after water injection, and the flexible thickness limiting component can deform in tandem with the surrounding similar materials under mining disturbance.

[0034] The flat water storage structure can be arranged in sections or filled with water in segments along the plane to form heterogeneous water conditions where local water-rich areas and relatively weak water-rich areas coexist.

[0035] The top and bottom plate water supply assembly includes a constant pressure water tank 15, a pneumatic booster pump 16, a one-way valve 17, a pressure relief valve, and a water delivery hose 18. Water in the constant pressure water tank 15 is injected into the flat water storage structure through the pneumatic booster pump 16 and the one-way valve 17. The water delivery hose 18 enters the filling space through the sealed pipe passage 33 on the left side plate 4 of the main frame 1 and communicates with the flat water storage structure.

[0036] The roof crack triggering component 11 is located at the bottom or side of the flat water storage structure and includes a thermal triggering unit and a sensing unit 24. When the mining-induced crack expands to a preset position, the sensing unit 24 sends a trigger signal to the main control module. The main control module controls the thermal triggering unit to heat or cut off the local vulnerable area of ​​the membrane layer, so that the flat water storage structure forms a crack. The water in the membrane cavity rushes down into the roadway or goaf along the crack channel, thereby simulating the roof water inrush process.

[0037] The base slab water damage simulation module includes a base slab pressurized water tank 19, a base slab crack triggering membrane assembly 20, and a base slab pressurized spray assembly. The base slab pressurized water tank 19 is located at the bottom of the filling space within the main frame 1; the base slab crack triggering membrane assembly 20 is located between the base slab pressurized water tank 19 and the upper filling layer; the base slab pressurized spray assembly includes a pneumatic booster pump 16, a one-way valve 17, and a water delivery hose 18. The base slab crack triggering membrane assembly 20 includes a porous support plate 201, which bears the upper pressure; an intelligent diversion valve 202 is connected to the water delivery hose 18 to evenly inject water into the base slab pressurized water tank 19.

[0038] When the crack in the base plate 3 expands to the preset trigger position, the main control module controls the base plate crack trigger membrane assembly 20 to open. Its working mode is the same as that of the top plate crack trigger assembly 11. At the same time, it drives the pneumatic booster pump 16 to pressurize and supply water to the base plate pressurized water tank 19, so that the water in the base plate pressurized water tank 19 rushes upward through the crack channel, thereby simulating the pressurized water inrush process of the base plate 3.

[0039] The rockburst simulation module is installed inside or near the critical load-bearing area of ​​the tunnel surrounding rock simulation structure. As an example, the rockburst simulation module includes a three-section tunnel surrounding rock simulation structure, a movable airbag energy release component 21, a segmented impact pin trigger component 22, an air pump supply component, and an airbag retraction positioning component 23. The three-section tunnel surrounding rock simulation structure consists of a first tunnel segment 26, a second tunnel segment 261, and a third tunnel segment 262, which are sequentially spliced ​​together. Each tunnel segment has an outer constraint layer and an inner brittle layer 27. The inner brittle layer 27 is made of a brittle-like material and is used to simulate the transient fracture of the tunnel inner wall under impact disturbance; the outer constraint layer is made of a high-strength, high-toughness similar material and is used to simulate large tunnel deformation caused by external pressure after the inner layer fractures.

[0040] The mobile airbag energy release assembly 21 is installed inside the tunnel and is connected to the external air pump supply assembly through a flexible high-pressure air pipe 213 that passes through the sealed operation channel of the right side plate 5 of the main frame 1.

[0041] The airbag retraction and positioning assembly 23 includes a traction rope and a drive motor 29. The mobile airbag energy release assembly 21 can be synchronously retracted along the roadway axis in the direction of mining advance. The traction rope in the airbag retraction and positioning assembly 23 passes through the sealed operating channel on the right side plate 5 and is connected to the external drive motor 29 to realize the synchronous retraction and positioning of the mobile airbag energy release assembly 21 along the roadway axis.

[0042] The segmented firing pin triggering components 22 are respectively disposed in the critical weak area inside the inner brittle layer 27 of each roadway segment. Each roadway segment is provided with at least one set of firing pin components. The firing pin components include firing pin seat 30, firing pin 31, elastic reset member and air impact plate 32.

[0043] Stress sensors 25 are installed on the outside of the tunnel. The stress sensors 25 can be evenly applied along the left and right sides of the tunnel. The connecting cables are arranged on the outside of the tunnel and connected to the external stress monitoring receiver through the sealed operating channel on the right side plate 5.

[0044] This application provides a test method for multi-element dynamic disasters under a thick loose layer. Based on the above-mentioned test apparatus, the working method includes the following steps: Step 1: Based on the burial depth, geological structure, aquifer distribution, roadway layout, and disaster research requirements of the target mine, determine the geometric dimensions, similarity ratio, mining advancement scheme, water supply parameters, and monitoring point layout scheme of the similar model, and complete the installation, connection, and initial state check of each module of the test system.

[0045] Step 2: According to the actual stratigraphic sequence and similar material ratio requirements of the target mine, similar materials are laid sequentially from bottom to top: floor layer, coal seam, bedrock layer, loose layer, and surface layer. After each layer is laid, the surface of the similar material is leveled, and the layer is compacted using the upper-loaded hydraulic plate 7 to ensure that the layer thickness, structural morphology, and density of each layer meet the test requirements. At the same time, the roadway simulation structure, roof water storage trigger component 10, floor pressure water tank 19, triggering elements, and monitoring elements are arranged synchronously at the corresponding layers. After the model is completed layer by layer, it is cured to make the similar model reach the predetermined test strength.

[0046] Step 3: After the model curing is completed, inject a predetermined amount of water into the top plate water storage trigger component 10 and the bottom plate pressure tank 19 respectively, and adjust the water injection range, water injection pressure and pressure conditions to form simulated hydrological conditions of the top plate aquifer, the water-rich area of ​​the loose layer and the bottom plate 3 pressure aquifer, and complete the setting of various parameters before the test.

[0047] Step 4: Proceed with the mining face mining according to the predetermined mining sequence, gradually expanding the goaf area and inducing the gradual development of migration responses such as overburden fracturing, bedrock fissure evolution, and overall settlement, horizontal slippage, and surface subsidence of the thick loose layer. During this process, the loose layer migration monitoring module 8 continuously acquires displacement change information from different monitoring points to characterize the overall response characteristics of the loose layer and the surface.

[0048] Step 5: As mining continues, when the overlying rock fissures expand to the preset stratum and meet the water conduction conditions, the top plate water storage triggering component 10 or the bottom plate fissure triggering membrane component 20 is triggered to release the water in the water storage structure, thereby simulating the top plate water inrush or the bottom plate 3 pressure water inrush, and recording the water inrush location, water inrush sequence and fissure penetration characteristics.

[0049] Step 6: Under the combined effects of large-scale migration of loose layers, fracture penetration, and water inrush disturbance, when the stress in the surrounding rock of the roadway reaches the preset triggering condition, the rockburst simulation module is activated. This causes the mobile airbag energy release component 21 to retract to the target roadway section and complete its positioning. Subsequently, the airbag is rapidly inflated to the set pressure and then instantly deflated. The released high-speed airflow pushes the impact plate 32, which in turn drives the striker 31 to shatter the inner brittle layer 27 of that section, thereby triggering a local rupture in the roadway. After the inner brittle layer 27 ruptures, under the combined action of similar external materials and boundary stress, the outer constraint layer converges and deforms inward into the roadway to simulate the large deformation process of the roadway after a rockburst.

[0050] Step 7: Throughout the entire experiment, the main control module synchronously collects and comprehensively analyzes information such as the migration of loose layers, the expansion of overburden fissures, water inrush from the roof and floor, stress changes in the surrounding rock of the tunnel, and impact instability, thereby obtaining the spatiotemporal evolution process of the multi-dynamic disaster chain under the thick loose layer.

[0051] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A multi-element dynamic testing device under a thick loose layer, characterized in that, include: The main framework is used to provide the model filling space and boundary constraints; The loose layer migration monitoring module is installed on the main frame, with its monitoring end extending into the interior of the main frame. It is used to continuously monitor the settlement, slippage, and surface subsidence characteristics of the thick loose layer under mining disturbance. A water inrush simulation module is installed inside the main frame to simulate the water inrush process of the top plate water and the bottom plate pressurized water under the condition of crack penetration. The water inrush simulation module includes a top plate water damage simulation module and a bottom plate water damage simulation module. The rockburst simulation module is installed in the roadway surrounding rock simulation structure inside the main frame. It is used to simulate the rupture, instability and large deformation of the roadway surrounding rock under the coupling effect of stress concentration and transient energy release. The rockburst simulation module includes: The simulated structure of the surrounding rock in the tunnel has an outer constrained layer and an inner brittle layer; A mobile airbag energy release assembly is installed inside the tunnel and connected to an external air supply assembly; The segmented impact pin trigger assembly is disposed on the inner side of the inner brittle layer and is used to break the inner brittle layer when the airbag releases energy. The segmented firing pin triggering components are respectively set in the critical weak area inside the inner brittle layer of each roadway segment. Each roadway segment is equipped with at least one set of firing pin components. The firing pin components include firing pin seat, firing pin, elastic reset component and air impact plate. The rockburst simulation module is activated, causing the mobile airbag energy release component to retract to the target roadway section and complete its positioning. Then, the airbag is controlled to be rapidly inflated to the set pressure and then instantly deflated. The high-speed airflow that is released pushes the impact plate to move, which in turn drives the striker to break the inner brittle layer of the section, thereby triggering a local rupture in the roadway. An airbag retraction and positioning component is connected to the mobile airbag energy release component, and is used to make it retract and position synchronously along the roadway axis with the mining advance direction; The main control module is electrically connected to the loose layer migration monitoring module, the water inrush simulation module, and the rockburst simulation module, and is used to perform coordinated control, trigger determination, and full-process data acquisition for each module.

2. The multi-element dynamic testing device under a thick loose layer according to claim 1, characterized in that, The main frame is a detachable rectangular frame, including a left side plate and a right side plate; the left side plate is provided with a sealed pipe passage, and the right side plate is provided with a sealed operation passage.

3. The multi-element dynamic testing device under a thick loose layer according to claim 2, characterized in that, The roof flooding simulation module includes: The roof water storage triggering component is set at the bottom of the pre-set aquifer or loose layer of the roof near the bedrock interface. It adopts a flat water storage structure with a flexible membrane and is equipped with a water injection interface that connects to an external water source. The top and bottom plate water supply assembly is connected to the top plate water storage trigger assembly and is used to inject water into the flat water storage structure; A top plate crack triggering component is disposed at the bottom or side of the flat water storage structure and is used to trigger the flat water storage structure to rupture and form a crack when the mining crack expands to a preset position.

4. The multi-element dynamic testing device under a thick loose layer according to claim 3, characterized in that, The bottom plate water damage simulation module includes: The base plate pressurized water tank is set at the bottom of the filled space within the main frame; A bottom plate crack triggering membrane assembly is disposed between the bottom plate pressurized water tank and the upper filling layer; The base plate pressurization spray assembly is connected to the base plate pressurized water tank and is used to pressurize and supply water to the base plate pressurized water tank.

5. The multi-element dynamic testing device under a thick loose layer according to claim 4, characterized in that, The rockburst simulation module also includes a stress sensor, which is located on the outside of the roadway and electrically connected to an external stress monitoring receiver.

6. The multi-element dynamic testing device under a thick loose layer according to claim 5, characterized in that, The main control module is electrically connected to the signal receiving component and the data acquisition component, and is used to coordinate the control of the water inrush simulation module and the rockburst simulation module, and to synchronously record and analyze the data collected by each monitoring module.

7. The multi-element dynamic testing device under a thick loose layer according to claim 6, characterized in that, The flat water storage structure of the top plate water storage trigger component has heterogeneous water distribution characteristics.

8. The multi-element dynamic testing device under a thick loose layer according to claim 7, characterized in that, The top plate crack triggering assembly includes a thermal triggering unit and a sensing unit. The sensing unit is used to send a signal when the mining crack expands to a preset position, and the thermal triggering unit is used to heat the water storage structure to form a crack.

9. A test method, characterized in that, The experimental method is based on the multi-element dynamic testing device under a thick loose layer as described in claim 8, and the experimental method includes the following steps: Step 1: Based on the geological conditions and disaster research requirements of the target mine, determine the geometric dimensions, similarity ratio, mining propulsion scheme and water supply parameters of the similar model, and complete the installation and initial status check of each module of the device; Step 2: Lay the bottom layer, coal seam, bedrock layer, loose layer and surface layer of similar materials in sequence from bottom to top. After each layer is laid, compaction is carried out. At the same time, roadway simulation structure, roof water storage structure, bottom water storage structure, triggering element and monitoring element are arranged in the corresponding layers. After the model is built, it is cured. Step 3: Inject a predetermined amount of water into the top plate water storage trigger component and the bottom plate pressurized water tank respectively, and adjust the water injection pressure and pressurization conditions to form simulated hydrological conditions; Step 4: Advance the mining of the working face according to the predetermined mining sequence to induce overburden fracturing, fracture evolution and loose layer migration, while continuously acquiring migration information through the loose layer migration monitoring module; Step 5: When the overlying rock fissures extend to the preset layer, trigger the top plate water storage triggering component or the bottom plate fissure triggering membrane component to release the water in the water storage structure, simulate the top plate water inrush or bottom plate pressure water inrush process, and record the water inrush location and timing. Step 6: When the stress of the surrounding rock in the roadway reaches the preset triggering condition, the rockburst simulation module is activated, causing the mobile airbag energy release component to retract to the target roadway section. The airbag is controlled to inflate rapidly and then deflate instantaneously, driving the segmented striker trigger component to break the inner brittle layer, simulating local rupture and large deformation of the roadway. Step 7: Throughout the entire experiment, the main control module synchronously collects and comprehensively analyzes information on loose layer migration, fracture propagation, water inrush, changes in surrounding rock stress, and impact instability to obtain the spatiotemporal evolution process of the multi-dynamic disaster chain.

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