Three-dimensional test device and method for simulating movement characteristics of overburden rock under mining influence
Patent Information
- Application Number
- CN202211581760.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-10
- Publication Date
- 2026-01-20
- Estimated Expiration
- 2042-12-10
Smart Images
Figure CN115901476B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a kind of simulation mining influence under overburden movement characteristic three-dimensional test device and method, belong to coal mining test research technical field. BACKGROUND
[0002] In recent years, with the increase of coal mining intensity, many mining areas gradually reduce the coal resources with good mining conditions.And the reserves of residual mining area upper residual coal seam are considerable, with good exploitation value, which can alleviate the problem of insufficient coal resources reserves in some mining areas, and effectively prolong the mining life of mining area.The mining of residual mining area upper residual coal seam makes the stability discrimination and safety problems increasingly prominent in the process of upward mining due to the existence of lower goaf.In order to ensure the safe and orderly progress of upward mining, the movement characteristics, broken range and crack propagation of overburden caused by lower coal seam mining need to be studied and analyzed.
[0003] Currently, the research on the movement law of overburden rock mainly has four methods of field measurement (CN 103742127 B, CN 103673982 B, CN 104315988 B, CN 107101617 B, CN 105019888 B), numerical simulation (CN 106884657 B, CN 110018290 A), physical simulation (CN 103489362 B, CN 105403684 B) and theoretical analysis (CN 103606019 B, CN 110766293 A, CN 105257337 B, CN 108694272 B). Among them, the field measurement method has long cycle, high cost, and is greatly affected by instruments and geological conditions; the numerical simulation is still difficult to accurately calculate the stress and deformation state of the rock mass under the mining condition due to the limitation of software, so that the simulation result often cannot reflect the real mining state; the theoretical analysis mainly has the "masonry beam" theory, the "transmission rock beam" theory, the "pressure arch" hypothesis, the "cantilever beam" hypothesis and the "hinged rock beam" hypothesis, and these hypotheses have corresponding assumptions and application scope, and there are inaccurate phenomena in the movement and damage judgment of the overburden rock. With the improvement of the similarity theory and simulation test technology, the physical similar simulation test has become a mainstream and efficient research means in the field of mining engineering. At present, the similar simulation test is mostly two-dimensional simulation test, the boundary conditions of the model are greatly simplified, and the deformation and damage of the overburden rock can only be observed on the surface, and the simulation result often also has great difference with the actual situation. The three-dimensional similar simulation test can overcome many shortcomings of the two-dimensional similar simulation test, and the test result is more in line with the actual mining situation. However, the three-dimensional similar simulation test mostly has the problems of single mining parameter, unable to directly observe the internal crack development of the model, and the same simulation platform cannot be applied to various mining methods. Therefore, it is necessary to invent a test device which can freely adjust the mining parameters, observe the breaking form and movement characteristics of the overburden rock internally and be applicable to various mining methods, so as to study the movement characteristics of the overburden rock after mining. SUMMARY
[0004] The present application aims to provide a three-dimensional test device which is simple in structure, convenient to use, can simulate various mining methods, freely adjust mining parameters, observe the breaking form and movement characteristics of the overburden rock internally and be applicable to various mining methods, and provide basic data for the subsequent feasibility discrimination of upward mining.
[0005] The present application simulates the actual stress state in the process of mining the ore body by using a three-way loading test device in the laboratory, adjusts the specific mining parameters according to the mining method of the ore body, simulates the actual process of mining the ore body, and realizes the visualization of the simulation of underground mining by observing the breaking form and movement characteristics of the overburden rock internally.
[0006] The application provides a three-dimensional test device for simulating the movement characteristics of overburden rock under mining influence, comprising a loading device, a test box and an overburden rock movement monitoring device.
[0007] The loading device comprises a press support frame, a hydraulic cylinder, an oil pressure controller and a test box pressing plate; the press support frame constitutes the outer frame of the whole triaxial test device, and comprises a press top plate, a press bottom plate and a press column; the press column is connected to the press top plate and the press bottom plate, and is embedded in the ground to form a stable and reliable connection; the hydraulic cylinder is fixed on the press support frame, one end of the hydraulic cylinder is connected to the oil pressure controller, the oil pressure controller provides oil pressure for the cylinder, the other end is connected to the test box pressing plate to provide confining pressure for the test box; the test box pressing plate is arranged on the outside of the test box body (on the upper, left, right, front and rear sides);
[0008] The test box comprises a box body and a coal and rock stratum simulation device; the box body comprises rigid box plates on the front, rear, left, right and upper parts and flexible deformable angle plates connected to the rigid box plates;
[0009] Preferably, the edge of the rigid box plate and the flexible deformable angle plate is provided with a row of bolt holes, and the rigid box plate and the flexible deformable angle plate are connected by bolts;
[0010] Preferably, the flexible deformable angle plate is made of one of PVC high-hardness soft plate, aluminum composite plate and resin soft plate;
[0011] The coal and rock stratum simulation device comprises a base plate, vertical lifting rods, small plates, hinged balls, a hinge controller and a small hydraulic controller; the base plate is a rectangular base plate made of a material with high rigidity, such as cast iron; the base plate is fixed on the press bottom plate; the vertical lifting rods are used for controlling the thickness of the simulated mining floor and the mining of the coal seam under different mining modes; the vertical lifting rods are fixed on the base plate and connected to the small hydraulic controller, and the vertical lifting rods are controlled to lift vertically by the small hydraulic controller to realize the lifting, simulate the mining and filling of the coal seam and the support force of the hydraulic support after mining; the vertical lifting rods are arranged in parallel and cover the whole base plate.
[0012] One vertical lifting rod and one small plate (each vertical lifting rod is connected to one small plate, and when the angle of the small plate on each vertical lifting rod is parallel to the ground, the planar area is approximately equal to the area of the base plate) are hinged by the hinged ball to control the angle of the small plate with the horizontal ground and simulate the stratum and coal seam inclination; the angle is adjustable, that is, the angle of the small plate with the horizontal ground is controlled by the hinge controller; the hinged ball controls the angle by the hinge controller, and the small plate is welded on the hinged ball, and the angle of the small plate with the horizontal ground is controlled by controlling the angle of the hinged ball;
[0013] Preferably, a row of bolt holes are arranged on the edge of the chassis, and the bolt holes are bolted with the flexible deformable gusset to form a closed test chamber with the rigid box plates on the front, back, left, right and top;
[0014] Preferably, the upper surface of the small plate is provided with a spring device to simulate the backfilling of the filling body after the coal seam is mined; the upper surface of the small plate is in contact with the rock stratum, and because the weight of the rock stratum is relatively large, the spring is always in a compressed state when placed on the small plate, and the height of the spring is small and can be ignored compared with the thickness of the entire overburden stratum.
[0015] The overburden movement monitoring device comprises a stress sensor, an acoustic emission sensor, a thermal infrared imager, a 3D laser scanner, a miniature high-definition camera and a data acquisition processor; the data acquisition processor is electrically connected with the stress sensor, the acoustic emission sensor, the thermal infrared imager, the 3D laser scanner and the miniature high-definition camera, records relevant data and stores and converts the data;
[0016] When the similar simulation material of the rock stratum is laid in the test chamber, a stress sensor is buried at the lower part of each layer of material to monitor the stress changes of each layer of rock stratum before and during mining in real time;
[0017] An acoustic emission sensor is placed at the edge of the similar material of the key stratum in the test chamber to monitor the acoustic emission signals and instantaneous elastic waves of the overburden stratum breaking to determine the time and position of the rock stratum breaking;
[0018] The thermal infrared imager is erected outside the test chamber at a height level with the central position of the test chamber to monitor the displacement and deformation of the overburden stratum before, during and after the coal seam mining to determine the breaking position and occurrence time of the overburden stratum;
[0019] The 3D laser scanner is used for panoramic scanning at each rock stratum laying stage and after the simulation test to obtain the appearances of each rock stratum before and after mining, and the 3D fracture reconstruction and numerical simulation calculation are performed through the image processing software and test data; the 3D laser scanner is erected on a movable support, a guide rail is installed on the surface of the movable support, a sliding block is arranged in the guide rail, and the sliding block is bolted with the 3D laser scanner to move and scan the 3D laser scanner; the movable support is not connected with the test chamber body and is a movable equipment, and the height of the 3D laser scanner erected on the support is higher than the height of the rock stratum laid in the test chamber.
[0020] Preferably, a row of small holes are arranged in the vertical direction on the plane of the chassis to enable the miniature high-definition camera to enter the simulated goaf from the chassis to observe the deformation and damage of the overburden stratum after various mining methods are used to record the formation and expansion process of the cracks. The miniature high-definition camera is similar to a probe and can enter the test chamber body from the small holes without being fixed on the chassis.
[0021] The application provides a three-dimensional test method for simulating movement characteristics of overburden rock under mining influence, and specific steps are as follows:
[0022] (1) selecting a simulation range of actual ore body mining test, testing physical and mechanical parameters of coal and rock in each stratum in the range, selecting similar simulation materials such as sand, gypsum, lime and cement according to the principle of similar simulation, and determining test amounts of various materials;
[0023] (2) forming bolt connection through bolt holes in the periphery of the base plate and flexible deformable angle plates, and connecting the flexible deformable angle plates with the front, rear, left and right rigid box plates to form a test box which is closed on four sides;
[0024] (3) according to the thickness and inclination of the simulated mining working face coal seam, adjusting the vertical lifting rod height and the hinged ball angle through the hydraulic controller and the hinged controller, so that the vertical lifting rod height is equal to the similar simulation height of the actual coal seam thickness, and the hinged ball angle is consistent with the actual coal seam inclination;
[0025] (4) according to the actual parameters of each stratum, mixing various similar simulation materials calculated in step (1) in proportion, and uniformly laying them on the simulation working face floor formed by the vertical lifting rod and the small flat plate in the test box according to the layer; wherein, during the laying of similar materials in each stratum, installing stress sensors at the lower part of each stratum, and placing acoustic emission sensors at the edge of similar materials of the key layer; and using a 3D laser scanner to scan each stratum after laying similar materials (without shooting the whole process, just scanning the surface of each stratum after laying), to obtain the appearance of each rock stratum before mining, and reconstructing the similar simulation test numerical model before mining through image processing software;
[0026] The stress sensors are arranged along the rock stratum inclination or strike in several lines, the distance between each line is 25±5cm, 3-6 stress sensors are arranged on each line, the distance between each stress sensor is 25±5cm, and the stress changes of each stratum before coal mining and each arrangement point during the coal mining process are monitored and collected in real time through the stress sensors;
[0027] The acoustic emission sensors are arranged at the edge of similar materials of the key layer in the test box, which is 20±3cm away from the edge of the test box body, and the acoustic emission signals of the overburden rock breaking are monitored and collected in real time;
[0028] (5) after the similar materials of the measured rock stratum are dry and hard, a 3D laser scanner is used to scan the uppermost rock stratum, and the test box is covered with the upper rigid box plate, the upper rigid box plate of the test box is bolted and fixed with the flexible deformable angle plate to form a complete test box;
[0029] (6) Activate the loading device. The hydraulic cylinder applies pressure to the test chamber through the test chamber pressure plate until the three-dimensional (three directions refer to the three-dimensional x, y, z directions, i.e., front and back, left and right, and up and down) loading pressure reaches the predetermined value. The predetermined value is the actual measured ground stress of the simulated mining strata. The loading process should be carried out simultaneously, and the three-dimensional stress loading rate should be constant and coordinated to reach the pressure control point as simultaneously as possible. After the loading is completed, record the stress measured by each stress sensor. Activate the thermal infrared imager to record the initial state of each simulated rock stratum before coal seam mining.
[0030] (7) Based on the actual mining method of the working face in the simulated area, a small hydraulic controller and a hinge controller are used to control the up and down movement of numerous vertical lifting rods on the chassis and the tilt angle of the small plate to accurately simulate coal seam mining; by coordinating and controlling whether each vertical lifting rod descends, the height and rate of descent, the height and rate of re-lifting after descent, etc., various working conditions and mining methods with different mining heights, mining widths and working face advance speeds are simulated.
[0031] During the experiment, a miniature high-definition camera was inserted into the goaf area inside the test chamber through a small hole in the chassis to observe in real time the deformation and damage of the overlying rock strata after mining under various mining methods and working conditions, and to record the formation and propagation process of cracks.
[0032] In addition, during the experiment, the stress sensor, acoustic emission sensor, and thermal infrared imager of the overburden movement monitoring device monitored and recorded the stress, deformation, and fracture parameters of the rock strata in real time.
[0033] (8) After the simulated excavation is completed, the external pressure of the test box is removed and the upper rigid box plate of the test box is dismantled; the model material is cleaned layer by layer from top to bottom. Before cleaning each layer, a 3D laser scanner is used to perform a panoramic scan to obtain the surface morphology of the layer. At the same time, a high-definition camera is used to record the cleaning process layer by layer to record the changes in the model profile; 3D crack reconstruction and numerical simulation calculation are performed by image processing software and combined with test data.
[0034] The beneficial effects of this invention are:
[0035] (1) This invention simulates different undulations of coal and rock strata by adjusting the height of the vertical lifting rod and the angle between the small plate and the horizontal plane. By controlling whether the vertical lifting rod descends, the height and rate of descent, and the height and rate of re-ascent after descent, it differs from the manual excavation of traditional similar simulation tests. It can accurately control the mining height, mining width and mining speed of the working face. At the same time, it can simulate various working conditions and mining methods such as hydraulic support or backfilling of the mining area after mining. It does not require dismantling the model test box, which reduces the external disturbance to the simulated rock strata and helps to improve the accuracy and reliability of the test results. At the same time, stress loading is applied in three dimensions of the test box, which can realistically simulate the stress state and deformation of the coal and rock mass during mining.
[0036] (2) Before the actual mining of the simulated working face, the present invention uses stress sensors, thermal infrared imagers, 3D laser scanners and other monitoring instruments in the overlying rock movement monitoring device to monitor the initial stress state and model shape of the model, and obtains the stress state and deformation of the model before the mining of the working face. Unlike the traditional simulation test, which only monitors the deformation and fracture of the overlying rock layer during and after mining, the test data is more complete and the amount of information is greater, providing a data basis for studying the fracture and movement characteristics of the overlying rock layer before, during and after mining.
[0037] (3) This invention uses a miniature high-definition camera to enter the simulated goaf area and observe the deformation and damage of the overlying rock strata after mining by various mining methods in real time, and records the formation and propagation process of cracks. Unlike traditional similar simulation tests, which can only observe the deformation of each rock stratum on the surface of the model, this invention can more accurately grasp the deformation and fracture of the rock body after mining, and provide a basis for the stability analysis of the overlying rock strata in the later stage.
[0038] (4) The present invention connects the rigid box plates at the front, back, left, right and top with flexible deformable corner plates to form a closed test box, which helps to prevent the rigid box plates from squeezing each other during the confining pressure loading process and ensures the smooth loading of triaxial confining pressure. Attached Figure Description
[0039] Figure 1 This is a schematic diagram of a three-dimensional test device for simulating the characteristics of overlying rock movement under the influence of mining.
[0040] Figure 2 This is a schematic diagram of the test chamber.
[0041] Figure 3 A schematic diagram (axonometric view) of the coal and rock strata simulation device for the test chamber.
[0042] Figure 4 This is a schematic diagram of a movable stand for a 3D laser scanner.
[0043] In the figure: 1 is the press bottom plate, 2 is the press top plate, 3 is the press column, 4 is the ground, 5 is the hydraulic cylinder, 6 is the test box pressing plate, 7 is the rigid box plate, 8 is the flexible deformable angle plate, 9 is the bolt, 10 is the base plate, 11 is the vertical lifting rod, 12 is the small flat plate, 13 is the hinged ball, 14 is the miniature high-definition camera, 15 is the 3D laser scanner, 16 is the guide rail, 17 is the sliding block, 18 is the oil pressure controller, 19 is the stress sensor, 20 is the acoustic emission sensor, 21 is the data acquisition processor, 22 is the thermal infrared imager, 23 is the box, 24 is the small hydraulic controller, 25 is the hinge controller, and 26 is the high-definition camera system. DETAILED DESCRIPTION
[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.
[0045] Combination Figures 1-4 As shown, the present application provides a three-dimensional test device for simulating the movement characteristics of overburden rock under mining influence, which comprises a loading device, a test box and an overburden rock movement monitoring device.
[0046] The loading device comprises a press support frame, a hydraulic cylinder 5, an oil pressure controller 18 and a test box pressing plate 6. The press support frame constitutes the outer frame of the entire triaxial test device, including a press top plate 2, a press bottom plate 1 and a press column 3. The press column 3 is connected to the press top plate 2 and the press bottom plate 1 and is embedded in the ground to form a stable and reliable connection. The test box is located inside the press support frame, and the test box is provided with a test box pressing plate 6 outside. The test box pressing plate 6 is uniformly connected to the hydraulic cylinder 5 outside. One end of the hydraulic cylinder 5 is fixed to the press support frame and is connected to the oil pressure controller 18 to provide oil pressure. The other end is fixed to the test box pressing plate 6 to provide confining pressure for the test box.
[0047] The test box comprises a box and a coal and rock layer simulation device. The box is connected as a whole by bolts 9 to the front, rear, left, right and upper rigid box plates 7 provided with a row of bolt holes on the edges and the flexible deformable angle plates 8 connecting the rigid box plates 7, forming a cubic structure box. The flexible deformable angle plates 8 are made of PVC high-hardness soft plates. Figure 1The layered structure seen in the middle is achieved by laying rock-soil layers of different materials.
[0048] The coal rock layer simulation device is composed of a base plate 10, a vertical lifting rod 11, a small flat plate 12, a hinged ball 13, a hinged controller 25 and a small hydraulic controller 24. The base plate is a rectangular base plate with a size of 2m x 1m made of cast iron, and the lower end is fixed to the bottom plate 1 of the press. A row of bolt holes is arranged on the periphery of the base plate, and the bolt holes are connected to the flexible deformable angle plate 8 by bolts to form a closed cubic test box with the front, rear, left, right and upper rigid box plates 7. Figure 3 The test box coal rock layer simulation device shown in the middle is a Figure 1 The oblique downward view angle is shown in the middle.
[0049] The vertical lifting rod 11 is fixed to the upper part of the base plate 10 and connected to the small hydraulic controller 24. The vertical lifting rod 11 is controlled by the small hydraulic controller 24 to control the vertical lifting height and the pressure in the vertical lifting rod, simulate the mining and filling of the coal seam, and the support force of the hydraulic support after mining. The upper part of the vertical lifting rod 11 is hingedly connected to a small flat plate 12 with a size of 5cm x 5cm through a hinged ball 13. The hinged ball 13 controls the angle between the small flat plate 12 and the horizontal ground through the hinged controller 25 to simulate the inclination of the stratum and coal seam.
[0050] Preferably, the upper surface of the small flat plate is provided with a spring device to simulate the backfilling of the filling body after the mining of the coal seam. That is, when the simulated ore body needs to be filled, the height of the vertical lifting rod can be first adjusted to determine the backfilling height of the filling body. At the same time, due to the existing technology, the filling body cannot completely adhere to the overburden rock to provide sufficient support force. At this time, the pressure on the spring is released and is no longer in a compressed state, which can provide a certain support to the overburden rock but does not provide a strong support force, thereby simulating the backfilling of the ore body.
[0051] The overburden rock movement monitoring device includes a stress sensor 19, an acoustic emission sensor 20, a thermal infrared imager 22, a 3D laser scanner 15, a miniature high-definition camera 14 and a data acquisition processor 21.
[0052] When laying rock layer similar simulation materials in the test box, stress sensors 19 are buried at the lower part of each layer of material, and acoustic emission sensors 20 are placed at the edges of the similar materials of the key layers to monitor the stress changes of each rock layer before and during mining and the acoustic emission signals of rock layer breakage to determine the time and position of rock layer breakage.
[0053] The thermal infrared imager 22 is erected outside the test box at a height level with the center position of the test box, and is used for monitoring the displacement and deformation of the overburden rock before, during and after the mining of the coal seam to determine the breakage position and occurrence time of the overburden rock.
[0054] The 3D laser scanner 15 is used for panoramic scanning in each rock stratum paving stage and after the simulation test ends, to obtain the appearance of each rock stratum before and after mining, and to perform 3D fissure reconstruction and numerical simulation calculation through image processing software and test data. The 3D laser scanner 15 is arranged on a movable support, the movable support is provided with a guide rail 16, a sliding block 17 is arranged in the guide rail 16, and the sliding block 17 is bolted with the 3D laser scanner 15, so that the 3D laser scanner 15 can move and scan. As shown in FIG. 1, the movable support is an independent device, which is independent of the upper part of the test box. When scanning is needed, the movable support is moved to the upper part of the test box, and the 3D laser scanner is moved into the unloaded space. When scanning is not needed, the movable support is moved out. Figure 4
[0055] A row of small holes are arranged in the vertical direction on the plane of the chassis 10, which are used for the miniature high-definition camera 14 to enter the simulated goaf from the chassis 10, to observe the deformation and damage of the overlying rock stratum after various mining methods are used for mining in real time, and to record the formation and expansion process of the cracks;
[0056] The data acquisition processor 21 is electrically connected with the stress sensor 19, the acoustic emission sensor 20, the thermal infrared imager 22, the 3D laser scanner 15 and the miniature high-definition camera 14, records relevant data and performs data storage and conversion.
[0057] The simulation working condition of the three-dimensional test method provided in the embodiment is that the working face mines the No. 22 coal seam, the average inclination of the coal seam is 4°, and the average thickness is 3.15 m. The immediate roof is fine sandstone, the thickness is 2.27 m, the main roof is medium sandstone, the thickness is 12.78 m, and the sandstone mudstone is 16.48 m. The overlying No. 19 coal seam has a thickness of 2 m, the immediate roof of the No. 19 coal seam is fine sandstone, the thickness is 4.6 m, and the main roof is medium fine sandstone, the thickness is 8.72 m. There is one fault with a drop of 1.6 m passing through the working face, and the distance from the working face to the cut opening is 300 m. The gas content of the coal is low. The longwall caving mining method is used in the working face, the average mining height is 3.15 m, the length of the working face is 150 m, and the strike length is 1000 m. The four-shift system is used in the working face, three shifts are used for production, one shift is used for maintenance, and the daily footage is 13.5 m.
[0058] The specific test steps are as follows:
[0059] (1) According to the simulation working condition, the physical and mechanical parameters of each coal seam and rock stratum in the working condition range are tested, it is determined that sand, gypsum and lime are selected as the similar simulation materials, and the test amount of each material is determined, as shown in Table 1.
[0060] Table 1: Physical and mechanical parameters of each coal seam and rock stratum and the amount of similar simulation materials
[0061]
[0062] (2) The 2m x 1m rectangular base plate is bolted to the flexible deformable corner plate through the bolt holes on the edges of the base plate, and the flexible deformable corner plate is connected to the rigid box plates in front, back, left and right with a height of 1.5m, forming a cuboid test box with four closed sides.
[0063] (3) According to the thickness and inclination of the coal seam in the simulated working face, the height of the vertical lifting rod on the left side of the fault is adjusted to 9.45cm, the height of the vertical lifting rod on the right side of the fault is adjusted to 14.28cm, and the angle of the small plate is 4° through the hydraulic controller and the hinge controller.
[0064] (4) The various similar simulation materials calculated in step (1) are mixed in proportion and uniformly laid on the simulated working face floor formed by the vertical lifting rod and the small plate in the test box. During the laying of the similar materials in each stratum, 3 measuring lines are arranged along the rock stratum inclination (the width direction of the test box) at the lower part of each stratum, with a measuring line spacing of 30cm, and 6 stress sensors are installed on each measuring line, with a stress sensor spacing of 30cm, to monitor the stress of each stratum before coal mining and the stress change of each arranged point during coal mining. Acoustic emission sensors are placed 20cm away from the edge of the test box in the similar material pre-judgment key layer to monitor and collect the acoustic emission signals of the overlying rock stratum failure in real time. At the same time, a 3D laser scanner is used to scan each stratum after the similar materials are laid to obtain the topography of each rock stratum before mining, and the similar simulation test numerical model before mining is reconstructed through image processing software.
[0065] (5) After the similar materials of the measured rock stratum are dry and hard, a 3D laser scanner is used to scan the uppermost rock stratum and cover it into the upper rigid box plate of the test box. The upper rigid box plate of the test box is bolted and fixed to the flexible deformable corner plate to form a complete closed cubic test box.
[0066] (6) Turn on the loading device, and the hydraulic oil cylinder applies pressure to the test box through the test box pressure plate at a constant loading rate until the three-direction loading pressure reaches the measured in-situ stress of the simulated mining stratum. After loading, record the stress measured by each stress sensor, and turn on the thermal infrared imager to record the initial state of each simulated rock stratum before coal mining.
[0067] (7) The simulation working condition adopts longwall caving mining method, positions of the first and second rows of vertical lifting rods and the small flat plate closest to the front rigid box plate are kept unchanged to simulate the ore pillar between two mining fields; first, the third, fourth, fifth, sixth, …, thirteenth and fourteenth rows of vertical lifting rods in the first row are sequentially lowered from front to back at a speed of 0.21 cm / min; second, when the vertical lifting rods in the first row are completely lowered to the original position, the third, fourth, fifth, sixth, …, thirteenth and fourteenth rows of vertical lifting rods in the second row are sequentially lowered from front to back at a speed of 0.21 cm / min; then, the third row, the fourth row, …, until the mining of the working face is completed are sequentially lowered from front to back.
[0068] During the test, the miniature high-definition camera enters the goaf range in the test box through the small hole in the chassis to observe the deformation and damage of the overburden strata after mining in real time and record the formation and expansion process of cracks.
[0069] In addition, the stress sensor, the acoustic emission sensor and the thermal infrared imager of the overburden movement monitoring device monitor the stress, deformation and breaking parameters of the strata in real time and record them during the test.
[0070] (8) After the simulation excavation is completed, the peripheral pressure of the test box is removed and the upper rigid box plate of the test box is removed. The model material is cleaned layer by layer from top to bottom along the layer surface, the 3D laser scanner is used to scan the panorama before each layer is cleaned to obtain the surface topography of the layer, and the high-definition camera is used to record the whole cleaning process to record the profile change of the model. Then, the 3D crack reconstruction and numerical simulation calculation are performed through the image processing software combined with the test data.
[0071] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A three-dimensional test device for simulating the movement characteristics of overburden under the influence of mining, characterized in that The utility model relates to a three-axial test device for simulating the movement of overburden rock, comprising a loading device, a test box and an overburden rock movement monitoring device. The loading device comprises a press support frame, a hydraulic cylinder, an oil pressure controller and a test box pressing plate; the press support frame constitutes the outer frame of the entire three-axial test device, including a press top plate, a press bottom plate and a press column; the press column connects the press top plate and the press bottom plate and is embedded in the ground; the hydraulic cylinder is fixed on the press support frame, with one end connected to the oil pressure controller and the other end connected to the test box pressing plate to provide confining pressure for the test box; the test box pressing plate is arranged on the outer side of the test box body. The test box comprises a box body and a coal and rock stratum simulation device; the box body comprises front, rear, left, right and upper rigid box plates and flexible deformable angle plates connecting the rigid box plates; The coal and rock stratum simulation device comprises a base plate, vertical lifting rods, small plates, hinged balls, a hinged controller and a small hydraulic controller; the base plate is a rectangular base plate made of a material with high rigidity; the base plate is fixed on the press bottom plate; the vertical lifting rods are used to control the thickness of the simulated mining floor and the mining of the coal seam under different mining methods; the vertical lifting rods are fixed on the base plate and connected to the small hydraulic controller to control the vertical lifting rods to achieve vertical lifting through the small hydraulic controller, simulate the mining and filling of the coal seam and the support force of the hydraulic support after mining; the vertical lifting rods are arranged in parallel and cover the entire base plate; each vertical lifting rod is connected to a small plate, and the angle between the small plate and the horizontal ground is controlled through the hinged controller; the hinged balls control the angle through the hinged controller, and the small plates are welded on the hinged balls; the angle between the small plates and the horizontal ground is controlled by controlling the angle of the hinged balls to simulate the stratum and coal seam inclination; the upper surface of the small plates is provided with a spring device to simulate the backfilling of the filling body after the mining of the coal seam through the spring force; the upper surface of the small plates is in contact with the rock stratum, and because the weight of the rock stratum is relatively large, the spring is always in a compressed state when placed on the small plates; The overburden movement monitoring device comprises a stress sensor, an acoustic emission sensor, a thermal infrared imager, a 3D laser scanner, a miniature high-definition camera and a data acquisition processor. The data acquisition processor is electrically connected with the stress sensor, the acoustic emission sensor, the thermal infrared imager, the 3D laser scanner and the miniature high-definition camera, records relevant data and stores and converts the data. When laying similar simulation materials in the rock strata in the test box, the stress sensor is embedded at the lower part of each layer of material to monitor the stress changes of each layer of rock strata before and during mining in real time. The acoustic emission sensor is placed at the edge of the similar material of the key layer in the test box to monitor the acoustic emission signals and instantaneous elastic waves of the overburden strata breaking to determine the time and position of the rock strata breaking. The thermal infrared imager is arranged outside the test box and has the same height as the center of the test box to monitor the displacement and deformation of the overburden strata before, during and after mining to determine the breaking position and time of the overburden strata. The 3D laser scanner is used for panoramic scanning during the laying of each rock stratum and after the simulation test. The miniature high-definition camera is arranged above the chassis inside the test box to monitor the deformation and damage of the overburden strata.
2. The three-dimensional test device for simulating the movement characteristics of overburden under mining influence according to claim 1, characterized in that: The edge of the rigid box plate and the flexible deformable angle plate is provided with a row of bolt holes, and the rigid box plate and the flexible deformable angle plate are connected by bolts.
3. The three-dimensional test device for simulating the movement characteristics of overburden under mining influence according to claim 1, characterized in that: The edge of the chassis is provided with a row of bolt holes, and the flexible deformable angle plate is connected by bolts to form a closed test box with the rigid box plates in front, back, left, right and top.
4. The three-dimensional test device for simulating the movement characteristics of overburden under mining influence according to claim 1, characterized in that: The 3D laser scanner obtains the appearance of each rock stratum before and after mining, and performs 3D crack reconstruction and numerical simulation calculation through image processing software and test data. The 3D laser scanner is arranged on a movable support, the movable support is provided with a guide rail, a sliding block is arranged in the guide rail, and the sliding block is connected with the 3D laser scanner by bolts to move and scan the 3D laser scanner. The movable support is not connected with the test box and is a movable equipment. The height of the 3D laser scanner arranged on the support is higher than the height of the rock stratum in the test box.
5. The three-dimensional test device for simulating the movement characteristics of overburden under mining influence according to claim 1, characterized in that: A row of small holes are arranged vertically on the plane of the chassis to allow the miniature high-definition camera to enter the simulated goaf from the chassis to observe the deformation and damage of the overburden strata after mining in real time and record the formation and expansion process of cracks.
6. A three-dimensional test method for simulating the movement characteristics of overburden under mining influence, using the three-dimensional test device for simulating the movement characteristics of overburden under mining influence according to any one of claims 1-5, characterized in that The specific steps are as follows: (1) Select the actual ore body mining test simulation range, test the physical and mechanical parameters of each stratum coal and rock in the range, select similar simulation materials such as sand, gypsum, lime and cement according to the principle of similar simulation, and determine the test amount of each material; (2) Form bolt connection with the flexible deformable angle plate through the bolt holes at the edge of the chassis, and connect the flexible deformable angle plate with the rigid box plates in front, back, left, right and top to form a closed test box. (3) According to the thickness and dip angle of the simulated mining face coal seam, the height of the vertical lifting rod and the angle of the hinged ball are adjusted through the hydraulic controller and the hinged controller, so that the height of the vertical lifting rod is equal to the similar simulation height of the actual coal seam thickness, and the angle of the hinged ball is consistent with the actual coal seam dip angle; (4) According to the actual parameters of each stratum, the various similar simulation materials calculated in step (1) are mixed in proportion and uniformly laid on the simulation working face floor composed of the vertical lifting rod and the small flat plate in the test box; wherein, during the laying process of each stratum similar material, stress sensors are installed at the lower part of each stratum, and acoustic emission sensors are placed at the edge of the similar material of the key layer; and a 3D laser scanner is used to panoramic scan each stratum after laying similar material to obtain the appearance of each rock stratum before mining, and the image processing software is used to reconstruct the similar simulation test numerical model before mining; (5) After the similar material of the measured rock stratum is dry and hard, the 3D laser scanner is used to scan the uppermost rock stratum, and the test box is covered with the upper rigid box plate, and the upper rigid box plate and the flexible deformable angle plate are connected and fixed with bolts to form a complete test box; (6) Turn on the loading device, the hydraulic oil cylinder applies pressure to the test box through the test box pressure plate until the three-way loading pressure reaches the predetermined value, which is the measured in-situ stress of the simulated mining stratum; the loading process should be carried out simultaneously, the three-way stress loading rate is constant, and the coordination is maintained, and the pressure control point is reached as much as possible; after loading, record the stress measured by each stress sensor; turn on the thermal infrared imager to record the initial state of each simulated rock stratum before coal mining; (7) According to the actual mining method of the simulated area working face, use a small hydraulic controller and a hinged controller to control the up and down movement of the numerous vertical lifting rods on the chassis and the inclination angle of the small flat plate, and accurately simulate coal mining; by coordinating the control of whether each vertical lifting rod descends, the height and rate of descent, and the height and rate of ascent after descending, various working conditions and mining methods with different mining height, mining width and working face advancing speed are simulated; During the test, the miniature high-definition camera enters the test box through the small hole in the chassis to the goaf range inside the test box, and the deformation and damage of the overburden strata after mining under various mining methods and various working conditions are observed in real time, and the formation and expansion process of cracks are recorded; In addition, the stress sensors, acoustic emission sensors and thermal infrared imagers of the overburden movement monitoring device monitor the stress, deformation and breaking parameters of the rock stratum in real time during the test, and record them; (8) After the simulation excavation is completed, the peripheral pressure of the test box is removed and the upper rigid box plate of the test box is removed; from top to bottom, the model material is cleaned layer by layer, and before cleaning each layer, a 3D laser scanner is used to panoramic scan to obtain the surface topography of the layer, and a high-definition camera is used to record the whole cleaning process to record the cross section change of the model; through the image processing software and combined with the test data, 3D crack reconstruction and numerical simulation calculation are carried out.
7. The three-dimensional test method for simulating the movement characteristics of the overburden strata under the influence of mining according to claim 6, characterized in that: In step (4), the stress sensors are arranged along the rock strata inclination or strike according to different mining methods, the interval of each measuring line is 25±5 cm, 3-6 stress sensors are arranged on each measuring line, the interval of each stress sensor is 25±5 cm, and the stress of each stratum before coal mining and the stress change of each arranged point during coal mining are monitored and collected in real time through the stress sensors; The acoustic emission sensors are arranged at the similar material edges of the pre-judged key layer in the test box, which is 20±3 cm away from the edge of the test box body, and the acoustic emission signals of the overburden strata breaking are monitored and collected in real time.