Coal mine underground reservoir dam body impact resistance stability simulation test device and method

Abstract

The invention provides a coal mine underground reservoir dam body anti-impact stability simulation test device and method.The device comprises a main body frame, a dam body model, dam body loading systems, an impact disturbance system, an impact energy monitoring system and a response measurement monitoring system, and the dam body loading systems are arranged on the upper portion and the two sides of the main body frame; the static load module is used for providing vertical static load force and transverse static load force for the dam body model; the impact disturbance system is arranged at the upper part of the main body frame and is used for applying a dynamic load force to a target position of the dam body model; the impact energy monitoring system is used for monitoring the impact speed and impact energy of the impact disturbance system; and the response measurement monitoring system is used for monitoring the response state of the dam body model when the dam body loading system and the impact disturbance system act. According to the method, the mechanical response characteristics and the deformation failure rule of the underground reservoir dam body under the impact load effect can be obtained, and the impact dynamic disaster breeding and causing mechanism of the underground reservoir dam body of the coal mine is disclosed.

Description

Technical Field

[0001] This application relates to the field of water resource protection and utilization technology in coal mining, and in particular to a simulation test device and method for the impact stability of underground reservoir dams in coal mines. Background Technology

[0002] Coal mine underground reservoirs are a new type of hydraulic structure that uses the goaf to store water, employing coal pillars and artificial dams to form a water-retaining structure, and equipped with water diversion facilities. The widespread application of coal mine underground reservoirs has increased mine water utilization to 83%, making a significant contribution to domestic and industrial water use in mining areas and greatly solving ecological and industrial water problems. During operation, the dam body is subjected to a complex disaster-prone environment and dynamic disturbances involving multiple phases (solid, liquid, and vapor) and multiple fields (dynamic and static stress fields, fracture fields, and seepage fields). Its structural stability has become a key factor affecting reservoir safety. Normally, the dam body maintains a state of equilibrium under these complex stress conditions due to the constraints of the roof and floor. Under these conditions, when the roof rock mass of the goaf collapses due to structural instability or sudden dynamic disasters, the impact on the water-rock mixture in the goaf will inevitably generate lateral impact loads on the dam structure. This equilibrium state may be broken, leading to dam failure and other safety accidents such as dam breakage, threatening the stability of the underground reservoir, personnel safety, and safe production in the coal mine.

[0003] Currently, the simulation of dynamic load disturbance is mostly achieved through drop hammer impact, and is mainly used to study the stability of roadways and roofs under dynamic load disturbance. For example, the bidirectional static and dynamic loading roof key block collapse test device and method disclosed in Chinese patent CN108827578A, and the multi-point multi-directional drop hammer impact device disclosed in Chinese patent CN209264234U, cannot realize the laying of coal mine underground reservoir dam body model and simulation of reservoir water storage environment in the main frame of the above-mentioned devices. Moreover, the drop hammer impact device cannot freely select the impact position within the reservoir water level, and the impact energy is limited by the drop hammer stroke, making it difficult to be applied to large-scale similar material simulation tests. It cannot simulate the impact disturbance of different intensity ranges caused by the collapse of rock masses of different volumes at different locations on the roof of the water storage area in the actual engineering environment of coal mine underground reservoirs. Summary of the Invention

[0004] The technical problem to be solved by this application is that the existing coal mining simulation devices cannot simulate the failure mechanism of coal mine underground reservoir dams under dynamic load impact disturbance and the deformation and failure law of the dam under impact load. Therefore, this application provides a test device and method for the impact stability of coal mine underground reservoir dams.

[0005] In a first aspect, the technical solution of this application provides a simulation test device for the impact stability of underground reservoir dams in coal mines, comprising a main frame and a dam model set within the main frame, a dam loading system mounted on the main frame, an impact disturbance system, an impact energy monitoring system, and a response measurement and monitoring system, wherein:

[0006] The dam loading system is set on the upper part and both sides of the main frame. The dam loading system set on the upper part is used to provide vertical static load to the dam model, and the dam loading system set on both sides is used to provide lateral static load to the dam model.

[0007] The impact disturbance system is installed on the upper part of the main frame, and the impact disturbance system is used to apply dynamic load force to the target position of the dam model;

[0008] The impact energy monitoring system is used to monitor the impact velocity and impact energy of the impact disturbance system.

[0009] The response measurement and monitoring system is used to monitor the response state of the dam model when the dam loading system and the impact disturbance system are activated.

[0010] The main frame of the simulation test device for the impact stability of underground reservoir dams in coal mines described in some schemes includes:

[0011] The base includes an upper steel plate, a lower steel plate, and a channel steel that are fixedly connected.

[0012] The simulation box includes a fixedly connected bottom frame and three side frames. A base upper steel plate is provided on the base frame. The dam model is laid on the base upper steel plate. A pad is provided between the dam model in the dam model and the dam loading system.

[0013] The anti-collision panel is connected to the two side frames of the simulated box through slots to form an enclosed space.

[0014] In some of the proposed solutions, the impact stability simulation test device for underground reservoir dams in coal mines uses a crash barrier made of transparent resin glass, and the strength value of the transparent resin glass meets the preset strength requirements.

[0015] Some of the proposed solutions describe a simulation test device for the impact stability of underground coal mine dams, wherein the dam loading system includes:

[0016] The loading truss includes a beam and columns connected to both sides of the beam, each column being connected to the base of the main frame.

[0017] A transverse loading cylinder is mounted on the column, and a transverse loading plate is mounted on its pressure head;

[0018] A vertical loading cylinder is mounted on the crossbeam, and a vertical loading plate is mounted on its pressure head.

[0019] In some schemes, the coal mine underground reservoir dam body impact stability simulation test device includes two transverse loading cylinders, which are respectively set on two columns;

[0020] The vertical loading cylinders include multiple cylinders, and the distance between two adjacent vertical loading cylinders is equal.

[0021] Some of the proposed solutions describe a simulation test device for the impact stability of underground reservoir dams in coal mines, wherein the impact disturbance system includes:

[0022] An impact truss includes a traveling truss, a first drive motor, and a first slide rail. The traveling truss is disposed on the upper part of the simulation box, the first drive motor is disposed on both sides of the traveling truss, and the first slide rail is disposed on the upper part of the side plate of the simulation box. The traveling truss moves freely along the first slide rail after being driven by the first drive motor.

[0023] The impact device includes an impact hammer, an impact launcher, a speed monitoring component, a second drive motor, and a second slide rail. The impact launcher is used to launch the impact hammer and provide acceleration assistance to the impact hammer. The speed monitoring component is disposed at the outlet end of the impact launcher and is used to monitor the initial launch speed of the impact hammer. The second drive motor is disposed on one side of the impact launcher, and the second slide rail is disposed on the upper part of the traveling truss. The impact launcher moves freely along the second slide rail after being driven by the second drive motor.

[0024] The impact energy monitoring system of the coal mine underground reservoir dam body impact stability simulation test device described in some schemes includes:

[0025] An impact velocity monitor is used to monitor the velocity of the impact hammer.

[0026] An acoustic emission signal acquisition instrument is used to monitor the impact stress of the impact hammer on the dam model;

[0027] The signal acquisition, processing and conversion unit is connected to the impact velocity monitor and the acoustic emission signal acquisition unit to obtain the impact energy of the impact hammer on the dam model.

[0028] Some schemes describe a simulation test device for the impact stability of underground reservoir dams in coal mines, wherein the response measurement and monitoring system includes: a pressure cell sensor, a strain sensor, and a distributed fiber optic strain sensor installed inside the dam model; a speckle pattern coated on the surface of the dam model; and a stress-strain acquisition instrument, a distributed fiber optic strain acquisition instrument, a speckle acquisition instrument, and a laser displacement meter installed outside the simulation chamber.

[0029] The stress-strain acquisition instrument receives the detection signals from the pressure cell sensor and the strain sensor to obtain the stress-strain value at the target location.

[0030] The distributed fiber optic strain acquisition instrument receives the detection signal from the distributed fiber optic strain sensor and obtains the strain value at the target location. The strain value verifies the detection result of the strain sensor.

[0031] The speckle sampling instrument is used to detect the positional changes of the speckles and obtain the lateral displacement of the dam model.

[0032] The laser displacement meter is used to detect the longitudinal displacement of the dam model.

[0033] Secondly, the technical solution of this application provides a method for simulating the impact stability of a coal mine underground reservoir dam body using the impact stability simulation test device described in any of the solutions of the first aspect, comprising the following steps:

[0034] Step 1: Based on the on-site information of the underground water reservoir in the coal mine to be analyzed and similarity theory, build a dam model in the simulation box;

[0035] Step 2: Based on the on-site information and similarity theory, simulate the water storage environment of the underground reservoir in the coal mine, lay crushed stone medium in the simulation box and fill it with water;

[0036] Step 3: Calculate the boundary force conditions of the dam model based on the original ground stress and stress similarity ratio, and apply lateral static load and vertical static load to the dam model through the dam loading system;

[0037] Step 4: Impact disturbance is applied to the target location of the dam model using an impact disturbance system. Simultaneously, the impact energy is recorded using an impact energy monitoring system, and the stress state data, acoustic emission data, and surface strain field data of the dam model are recorded using a response measurement and monitoring system. The data also include the crack propagation law, instability and slippage process, and failure mode of the dam model during the disturbance process.

[0038] Step 5: Analyze the mechanism of the dam model's instability and sliding caused by the impact disturbance based on the recorded monitoring data, obtain the changes and abrupt changes of various data recorded by the response measurement and monitoring system, determine the critical conditions and precursor information of the dam model's instability, and obtain the impact stability test results of the dam model.

[0039] Some schemes describe a method for simulating the impact stability of underground reservoir dams in coal mines. Step 1 includes: setting up a model template; preparing similar materials according to the optimal similar material formula and laying them layer by layer; during the laying process, embedding pressure cell sensors and distributed fiber optic strain sensors in layers to obtain a similar dam model; curing the similar dam model to the expected strength; and removing the model template to obtain the dam model.

[0040] Step 2 includes: removing the model template, laying crushed stone medium to simulate water storage space inside the simulation box, with the laying height being the same as the height of the dam model; calculating the simulated water storage height based on the similarity ratio, and injecting water into the crushed stone medium until the water injection height reaches the simulated water storage height.

[0041] The above technical solution has the following beneficial effects:

[0042] This application provides a simulation test device and method for the impact stability of underground reservoir dams in coal mines. The device includes: a main frame, a dam model, a dam loading system, an impact disturbance system, an impact energy monitoring system, and a response measurement and monitoring system. The dam loading system is located on the upper part and both sides of the main frame, providing vertical and lateral static loads to the dam model. The impact disturbance system is located on the upper part of the main frame, applying dynamic loads to target locations on the dam model. The impact energy monitoring system monitors the impact velocity and impact energy of the impact disturbance system. The response measurement and monitoring system monitors the response state of the dam model when the dam loading system and the impact disturbance system are activated. This application can obtain the mechanical response characteristics and deformation and failure laws of underground reservoir dams under impact loads, revealing the mechanism of impact dynamic disasters in underground reservoir dams in coal mines, which is of great significance for ensuring energy resource security and sustainable socio-economic development. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of a coal mine underground reservoir dam impact stability simulation test device in one embodiment of this application;

[0044] Figure 2 This is a schematic diagram from another perspective of the simulation test device for the impact resistance stability of a coal mine underground reservoir dam in one embodiment of this application;

[0045] Figure 3This is another schematic diagram of the impact resistance stability simulation test device for a coal mine underground reservoir dam body in one embodiment of this application;

[0046] Figure 4 This is a schematic diagram of the structure of a security isolation grid in one embodiment of this application;

[0047] Figure 5 This is a schematic diagram of the structure of a model template in one embodiment of this application;

[0048] Figure 6 A schematic diagram of an experimental method for simulating the impact stability of a coal mine underground reservoir dam in one embodiment of this application;

[0049] Figure 7 Another perspective schematic diagram of a simulation test method for the impact stability of an underground reservoir dam in a coal mine, as described in one embodiment of the application. Detailed Implementation

[0050] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0051] It is readily understood that, based on the technical solution of this application, various structural and implementation methods can be interchanged by those skilled in the art without altering the essential spirit of this application. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this application and should not be considered as the entirety of this application or as limitations or restrictions on the technical solution of the application.

[0052] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. They are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.

[0053] This application provides a test device for the impact stability of underground reservoir dams in coal mines, including a main frame, a dam model set within the main frame, a dam loading system mounted on the main frame, an impact disturbance system, an impact energy monitoring system, and a response measurement and monitoring system. Specifically, the main frame is used to mount other systems, provide reaction forces, and load the dam model.

[0054] Among them, such as Figures 1 to 3 As shown, the main frame includes: a base 1, a simulated box 2, and a crash barrier 3. The base 1 is welded from an upper steel plate, a lower steel plate, and a channel steel, with through holes and anchor bolt holes reserved where needed.

[0055] The simulation box 2 is welded together from a bottom frame and three side frames (i.e., the two side frames and the rear frame). The simulation box 2 has a good overall seepage prevention effect. Its bottom frame is connected to the upper steel plate of the base 1 by bolts. The dam model is laid in the internal space of the simulation box 2. The anti-collision enclosure 3 is made of high-strength transparent resin glass. That is, the strength value of the transparent resin glass reaches the preset strength requirement. It can be connected to the two side frames of the simulation box 2 through slots to form a closed space, which is used to prevent the dam model from being damaged by impact and causing block splashes that could damage the response measurement and monitoring system.

[0056] like Figure 1 and Figure 3 As shown, the dam loading system includes: a loading truss 4, vertical loading cylinders 5 and vertical loading plates 6, and horizontal loading cylinders 7 and horizontal loading plates 8. The loading truss 4 is formed by welding a crossbeam and two side columns, with the side columns securely connected to the base 1 of the main frame. One horizontal loading cylinder 7 is mounted on the side of each of the two truss columns. The horizontal loading plate 8 is installed on the pressure head of the horizontal loading cylinder 7 and is connected to the side of the dam model to apply a horizontal static load to the dam model. Multiple vertical loading cylinders 5 are axially mounted on the crossbeam of the truss. In this embodiment, four vertical loading cylinders 5 are used as an example. The vertical loading plate 6 is installed on the pressure head of the four vertical loading cylinders 5 and is connected to the upper part of the dam model to apply a vertical static load to the dam model.

[0057] Combination Figure 1 and Figure 2 As shown, the impact disturbance system includes an impact truss and an impact device. The impact truss includes a traveling truss 9, a first drive motor 10, and a first slide rail 11. The traveling truss 9 is welded from steel plates and is mounted on the upper part of the simulation box 2 of the main frame. The first drive motor 10 is mounted on one side of the traveling truss 9, and the first slide rail 11 is mounted on the upper part of the side plate of the simulation box 2. The traveling truss 9 moves freely along the first slide rail 11 driven by the first motor 10.

[0058] like Figures 1 to 3 As shown, the impact device includes an impact hammer 12, an impact launcher 13, a velocity monitoring component 14, a second drive motor 15, and a second slide rail 16. The impact hammer 12 is made of stainless steel and is inserted into the impact launcher 13 during testing. The impact launcher 13 launches the impact hammer 12, providing acceleration assistance for the impact hammer 12 to simulate dynamic load disturbances on the dam model. The velocity monitoring component 14 is installed at the outlet end of the impact launcher 13 to measure the initial launch velocity of the impact hammer 12. The second drive motor 15 is installed on the side of the impact launcher 13, and the second slide rail 16 is installed on the upper part of the traveling truss 9. The impact launcher 13 moves freely along the second slide rail 16 via the second drive motor 15.

[0059] The impact energy monitoring system is used to monitor the impact velocity and impact stress wave of the impact hammer 12. The system includes: an impact velocity monitor 17 to monitor the velocity of the impact hammer; an acoustic emission signal acquisition unit 18 to monitor the impact stress of the impact hammer on the dam model; and a signal acquisition, processing, and conversion unit 19 connected to the impact velocity monitor 17 and the acoustic emission signal acquisition unit 18 to obtain the impact energy of the impact hammer 12 on the dam model. The acoustic emission signal acquisition unit 18 monitors the sound signal because the impact velocity of the impact hammer 12 can be monitored, and the sound signal attenuates upon impact with the dam model; the attenuation of the sound signal reflects the magnitude of the impact force received by the dam. Through calibration tests, the decibel level of the sound generated when the impact hammer hits the dam can be determined. Then, based on the sound signal acquired by the acoustic emission signal acquisition unit 18, the detected decibel level can be obtained. The change in this decibel value can be used to deduce how much energy is absorbed by the dam after the impact hammer applies an impact force. In addition, the acoustic emission signal acquisition instrument 18 can also collect acoustic emission signal parameters of micro-fractures, which can be used to analyze the crack propagation law and the damage evolution law of the dam model.

[0060] The response measurement and monitoring system is used to achieve various response monitoring functions, including surface fixed-point displacement monitoring, surface fixed-point strain monitoring, internal fixed-point pressure monitoring, surface strain / displacement field monitoring, acoustic emission monitoring, and surface fault displacement monitoring. The response measurement and monitoring system includes: a pressure cell sensor, a strain sensor, a stress-strain acquisition instrument 20, a speckle strain measurement system 21, a laser displacement gauge 23, and a distributed fiber optic strain acquisition instrument 24. The laser displacement gauge 23 uses a laser sensor, and the speckle strain measurement system 21 uses a camera supported by a bracket 22. In practical implementation, the pressure cell sensor, strain sensor, and distributed fiber optic strain sensor are installed inside the dam model; speckle pattern is coated on the surface of the dam model, and the speckle strain measurement system 21 includes a camera. By capturing the positional changes of the speckle pattern, the lateral displacement of the dam model can be obtained; the laser displacement meter 23 emits a laser beam into the dam model. Based on the wavelength of the laser beam, the time after the laser beam is emitted, and the time after the laser beam is reflected and received, the distance between the laser and the dam model can be determined. Through multiple measurements, if the distance changes, it indicates that the dam model has undergone longitudinal displacement, and the longitudinal displacement can be determined based on the distance change value. In practical implementation, the stress-strain acquisition instrument, distributed fiber optic strain acquisition instrument, speckle acquisition instrument, and laser displacement meter can all be installed outside the simulation box.

[0061] like Figure 4 and Figure 5As shown, the experimental setup also includes model templates and safety isolation netting 28. The model templates are used to assist in laying dam models of different sizes and specifications; they can be removed after the dam model is formed. The model templates include: a main template 25, a coal pillar dam template 26, and an artificial dam template 27. Constructing the dam model includes: ① connecting and fixing the main template 25 to the side plate of the simulation box 2 at the main template position using bolts; ② inserting the coal pillar dam template 26 into the main template 25; ③ filling the space formed by the main template 25, the coal pillar dam template 26, and the side plate of the simulation box 2 with similar simulation material to construct the coal pillar dam; ④ removing the coal pillar dam template 26 after the coal pillar dam model has cured and formed; ⑤ brushing a release agent on the inside of the artificial dam template 27, inserting it into the remaining space of the main template 25, and pouring similar simulation material to construct a similar artificial dam model; ⑥ removing the artificial dam template 27 after the artificial dam model has formed; ⑦ curing the entire dam model, and removing all templates after curing and forming. Safety isolation netting 28 is installed around the entire test device to isolate the test device and personnel, ensuring the safety of personnel during the test.

[0062] The above-mentioned solution of the present invention studies the impact stability of the dam structure from the perspective of the impact disturbance caused by the sudden collapse of the roof rock strata in the reservoir area of ​​a coal mine, and is applicable to the study of most impact dynamic disaster accidents. Specifically, the main frame can realize the laying of a large-scale coal mine underground reservoir dam model and the simulation of the water storage environment in the reservoir. The impact device can freely select the impact position within the plane of the coal mine underground reservoir reservoir area to simulate the impact disturbance of different intensity ranges caused by the collapse of rock masses of different positions and volumes in the reservoir roof. The drop hammer impact method adopted in this application can achieve precise and controllable impact energy.

[0063] like Figure 6 and Figure 7 As shown, the technical solution of this application also provides a simulation test method for the impact stability of underground reservoir dams in coal mines. This method simulates impact disturbances of different intensities caused by the collapse of overlying rock strata at different locations within the reservoir area. It observes the crack propagation law, instability and slippage process, and failure mode of the dam body during the disturbance process. It analyzes the deformation and failure law of the dam body under impact load, explores the precursor information of the failure process, and reveals the failure mechanism of underground reservoir dams in coal mines under dynamic impact disturbance, providing a theoretical basis for disaster prevention and early warning. The method specifically includes:

[0064] Step 1: Based on the on-site information of the underground reservoir of the coal mine to be analyzed and similarity theory, build a dam model in the simulation box.

[0065] In this step, based on the on-site information and similarity theory of the underground reservoir in the coal mine to be analyzed, an overall model of the dam body is constructed. A model template is then used to construct the dam body model of the underground reservoir within the simulation box 2 of the main frame. Specifically, this includes:

[0066] Step 1.1: Based on the on-site information of the underground reservoir of the coal mine to be analyzed, divide the appropriate simulation range, determine the size similarity ratio, strength similarity ratio, density similarity ratio and stress similarity ratio according to the similarity theory to meet the similarity conditions, and calculate the model size, model density and model strength.

[0067] Step 1.2: Based on the calculated model density and model strength, select suitable similar materials, and through multiple orthogonal experiments, select the best similar material formula and curing method; in specific implementation, based on the similarity ratio parameters determined by similarity theory, use similar material raw materials such as quartz sand, white cement, talc powder, barite, silicone oil, and water, and study the appropriate similar material preparation formula, curing method, and time through orthogonal experiments.

[0068] Step 1.3: Based on the obtained model dimensions and similar material formula, lay the dam model. The specific laying process is as follows: ① Connect and fix the main template 25 to the side plate of the simulation box 2 at the molding position using bolts; ② Insert the coal pillar dam template 26 into the main template 25; ③ Fill the space formed by the main template 25, the coal pillar dam template 26 and the side plate of the simulation box 2 with similar simulation material. During the laying of the coal pillar dam, pressure box sensors, strain sensors and distributed optical fibers are embedded in layers; ④ After the coal pillar dam model is cured and formed, remove the coal pillar dam template 26; ⑤ Apply release agent to the inside of the artificial dam template 27, insert it into the remaining space of the main template 25, and pour similar simulation material. During the pouring of the artificial dam, pressure box sensors, strain sensors and distributed optical fibers are embedded in layers; ⑥ After the artificial dam model is formed, remove the artificial dam template 27; ⑦ Cure the entire dam model. After curing and forming, remove all templates.

[0069] The model laying template provided by this invention can realize the laying and shaping of dam models of different sizes and specifications.

[0070] Step 2: Based on the on-site information and similarity theory, simulate the water storage environment of the underground reservoir in the coal mine, lay crushed stone medium in the simulation box and fill it with water.

[0071] In this step, based on site information and similarity theory, the water storage environment of an underground coal mine reservoir is simulated. Crushed stone media is laid and water is injected into the simulated tank 2 within the main frame. Specifically, this includes:

[0072] Step 2.1: After removing the model template, lay crushed stone medium to simulate the water storage space inside the simulation box 2 of the main frame. The laying height is the same as that of the dam model, and set up an acoustic emission signal acquisition instrument 18 at the predetermined position.

[0073] Step 2.2: Calculate the simulated water storage height based on the similarity ratio, and inject water into the gravel medium laid in the simulated box 2 of the main frame.

[0074] Step 3: Calculate the boundary force conditions of the dam model based on the original ground stress and stress similarity ratio, and apply lateral static load and vertical static load to the dam model through the dam loading system.

[0075] In this step, the boundary force conditions of the dam model are calculated based on the original ground stress and stress similarity ratio. Lateral and vertical static loads are then applied to the dam model using the dam loading system. Specifically, the vertical loading cylinder 5 is controlled to slowly advance the vertical loading plate 6 to contact the upper surface of the dam model. Once all four vertical loading plates 6 are in contact, the vertical loading cylinder 5 and the lateral loading cylinder 7 are controlled to apply the lateral and vertical static loads to the dam model to the predetermined load values ​​based on the stress values ​​calculated using the stress similarity ratio, and these loads are then kept constant.

[0076] Step 4: Impact disturbance is applied to the target location of the dam model using an impact disturbance system. Simultaneously, the impact energy is recorded using an impact energy monitoring system, and the stress state data, acoustic emission data, and surface strain field data of the dam model are recorded using a response measurement and monitoring system. The data also include the crack propagation law, instability and slippage process, and failure mode of the dam model during the disturbance process.

[0077] In practice, based on the analysis objectives, the required impact energy, impact velocity, and mass of the impact hammer 12 are calculated using a similarity ratio. The first motor drive 10 drives the traveling truss 9, and the second motor drive 15 drives the impact launcher 13 to reach the predetermined impact position. A suitable impact hammer 12 is selected and installed into the impact launcher 13, and the safety isolation fence 28 is closed. The impact launcher 13 is remotely controlled to launch the impact hammer 12 at the required impact velocity to create an impact disturbance.

[0078] Step 5: Analyze the mechanism of the dam model's instability and sliding caused by the impact disturbance based on the recorded monitoring data, obtain the changes and abrupt changes of various data recorded by the response measurement and monitoring system, determine the critical conditions and precursor information of the dam model's instability, and obtain the impact stability test results of the dam model.

[0079] In practice, after the impact, the lateral and vertical loading forces are unloaded to zero. The safety isolation grid 28 is then opened. During the static loading and dynamic disturbance processes, the crack propagation law, instability slippage process, and failure mode of the dam model are observed throughout the impact disturbance process. Stress state data, acoustic emission data, and surface strain field data of the dam model are collected and recorded. Based on the recorded stress and strain data, the initial stress conditions of the dam model are analyzed, and the crack propagation process of the dam model is analyzed based on the recorded acoustic emission signals to identify the critical instability conditions and precursor information, and to evaluate the impact resistance stability of the dam model.

[0080] The experimental setup provided in this application can be used to study the dynamic impact disturbance of a coal mine underground reservoir dam caused by the sudden collapse of the overlying rock strata in the reservoir's storage area. By changing the impact location and energy, it can simulate impact disturbances of different intensities caused by the collapse of overlying rock strata at different locations within the reservoir area. Changing the number of impact disturbances can also simulate single impact disturbances and multiple cyclic impact disturbances. Adjusting the similarity ratio can change the model size, enabling the study of the impact stability of dams of various sizes. By acquiring acoustic emission signal parameters of micro-fractures through the acoustic emission acquisition device in the response measurement and monitoring system, the crack propagation law and the damage evolution law of the dam model can be analyzed. By acquiring stress parameters of the model through embedded pressure cell sensors, the stress evolution law of the dam model can be analyzed. By acquiring strain parameters of the model through embedded or surface strain sensors, the strain evolution law of the dam model can be analyzed. By acquiring displacement parameters of the dam model through a speckle strain measurement system and a laser displacement meter, the deformation and movement law of the dam model can be analyzed. Meanwhile, analysis can be performed on all the above parameters to obtain the changing trends and abrupt change patterns of each parameter during the instability and slippage of the dam model, extract information on the precursors of instability and abrupt change, and provide a theoretical basis for disaster prevention and early warning.

[0081] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0082] The above are merely the principles and preferred embodiments of this application. It should be noted that, for those skilled in the art, several other modifications can be made based on the principles of this application, and these modifications should also be considered within the scope of protection of this application.

Claims

1. A simulation test device for the impact stability of underground reservoir dams in coal mines, characterized in that, It includes a main frame and a dam model set within the main frame, a dam loading system mounted on the main frame, an impact disturbance system, an impact energy monitoring system, and a response measurement and monitoring system, wherein: The dam loading system is set on the upper part and both sides of the main frame. The dam loading system set on the upper part is used to provide vertical static load to the dam model, and the dam loading system set on both sides is used to provide lateral static load to the dam model. The impact disturbance system is installed on the upper part of the main frame, and the impact disturbance system is used to apply dynamic load force to the target position of the dam model; The impact energy monitoring system is used to monitor the impact velocity and impact energy of the impact disturbance system. The response measurement and monitoring system is used to monitor the response state of the dam model when the dam loading system and the impact disturbance system are activated.

2. The simulation test device for the impact stability of underground reservoir dams in coal mines according to claim 1, characterized in that, The main framework includes: The base includes an upper steel plate, a lower steel plate, and a channel steel that are fixedly connected. The simulation box includes a fixedly connected bottom frame and three side frames. A base upper steel plate is provided on the base frame. The dam model is laid on the base upper steel plate. A pad is provided between the dam model in the dam model and the dam loading system. The anti-collision panel is connected to the two side frames of the simulated box through slots to form an enclosed space.

3. The simulation test device for the impact stability of underground reservoir dams in coal mines according to claim 2, characterized in that: The crash barrier is made of transparent resin glass, and the strength value of the transparent resin glass meets the preset strength requirements.

4. The simulation test device for the impact stability of underground reservoir dams in coal mines according to claim 2, characterized in that, The dam loading system includes: The loading truss includes a beam and columns connected to both sides of the beam, each column being connected to the base of the main frame. A transverse loading cylinder is mounted on the column, and a transverse loading plate is mounted on its pressure head; A vertical loading cylinder is mounted on the crossbeam, and a vertical loading plate is mounted on its pressure head.

5. The simulation test device for the impact stability of underground reservoir dams in coal mines according to claim 4, characterized in that: The lateral loading cylinder includes two cylinders, which are respectively mounted on the two columns. The vertical loading cylinders include multiple cylinders, and the distance between two adjacent vertical loading cylinders is equal.

6. The simulation test device for the impact stability of underground reservoir dams in coal mines according to claim 2, characterized in that, The shock disturbance system includes: An impact truss includes a traveling truss, a first drive motor, and a first slide rail. The traveling truss is disposed on the upper part of the simulation box, the first drive motor is disposed on both sides of the traveling truss, and the first slide rail is disposed on the upper part of the side plate of the simulation box. The traveling truss moves freely along the first slide rail after being driven by the first drive motor. The impact device includes an impact hammer, an impact launcher, a speed monitoring component, a second drive motor, and a second slide rail. The impact launcher is used to launch the impact hammer and provide acceleration assistance to the impact hammer. The speed monitoring component is disposed at the outlet end of the impact launcher and is used to monitor the initial launch speed of the impact hammer. The second drive motor is disposed on one side of the impact launcher, and the second slide rail is disposed on the upper part of the traveling truss. The impact launcher moves freely along the second slide rail after being driven by the second drive motor.

7. The simulation test device for the impact stability of underground reservoir dams in coal mines according to claim 6, characterized in that, The impact energy monitoring system includes: An impact velocity monitor is used to monitor the velocity of the impact hammer. An acoustic emission signal acquisition instrument is used to monitor the impact stress of the impact hammer on the dam model; The signal acquisition, processing and conversion unit is connected to the impact velocity monitor and the acoustic emission signal acquisition unit to obtain the impact energy of the impact hammer on the dam model.

8. The simulation test device for the impact stability of underground reservoir dams in coal mines according to claim 7, characterized in that: The response measurement and monitoring system includes: a pressure cell sensor, a strain sensor, and a distributed fiber optic strain sensor installed inside the dam model; a speckle pattern coated on the surface of the dam model; and a stress-strain acquisition instrument, a distributed fiber optic strain acquisition instrument, a speckle acquisition instrument, and a laser displacement meter installed outside the simulation box. The stress-strain acquisition instrument receives the detection signals from the pressure cell sensor and the strain sensor to obtain the stress-strain value at the target location; The distributed fiber optic strain acquisition instrument receives the detection signal from the distributed fiber optic strain sensor and obtains the strain value at the target location. The strain value verifies the detection result of the strain sensor. The speckle sampling instrument is used to detect the positional changes of the speckles and obtain the lateral displacement of the dam model. The laser displacement meter is used to detect the longitudinal displacement of the dam model.

9. A method for simulating the impact stability of a coal mine underground reservoir dam body using the impact stability simulation test device according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Based on the on-site information of the underground water reservoir in the coal mine to be analyzed and similarity theory, build a dam model in the simulation box; Step 2: Based on the on-site information and similarity theory, simulate the water storage environment of the underground reservoir in the coal mine, lay crushed stone medium in the simulation box and fill it with water; Step 3: Calculate the boundary force conditions of the dam model based on the original ground stress and stress similarity ratio, and apply lateral static load and vertical static load to the dam model through the dam loading system; Step 4: Impact disturbance is applied to the target location of the dam model using an impact disturbance system. Simultaneously, the impact energy is recorded using an impact energy monitoring system, and the stress state data, acoustic emission data, and surface strain field data of the dam model are recorded using a response measurement and monitoring system. The data also include the crack propagation law, instability and slippage process, and failure mode of the dam model during the disturbance process. Step 5: Analyze the mechanism of the dam model's instability and sliding caused by the impact disturbance based on the recorded monitoring data, obtain the changes and abrupt changes of various data recorded by the response measurement and monitoring system, determine the critical conditions and precursor information of the dam model's instability, and obtain the impact stability test results of the dam model.

10. The method for simulating the impact stability of underground reservoir dams in coal mines according to claim 9, characterized in that: Step 1 includes: setting up a model template; preparing similar materials according to the optimal similar material formula and laying them layer by layer; during the laying process, embedding pressure cell sensors and distributed fiber optic strain sensors in layers to obtain a dam body similar model; curing the dam body similar model to the expected strength, and removing the model template to obtain the dam body model. Step 2 includes: removing the model template, laying crushed stone medium to simulate water storage space inside the simulation box, with the laying height being the same as the height of the dam model; calculating the simulated water storage height based on the similarity ratio, and injecting water into the crushed stone medium until the water injection height reaches the simulated water storage height.

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