CN219245239U - Three-dimensional test device for simulating overburden rock movement characteristics under mining influence - Google Patents

Abstract

The utility model discloses a three-dimensional test device for simulating the movement characteristics of overburden rock under the influence of mining, which comprises a loading device, a test box and a overburden rock movement monitoring device; the loading device comprises a press machine support frame, a hydraulic cylinder, an oil pressure controller and a test box pressing plate; the test box comprises a box body and a coal stratum simulation device; the coal stratum simulation device comprises a chassis, a vertical lifting rod, a small flat plate, a hinged ball, a hinged controller and a small hydraulic controller; the overlying strata 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 utility model has simple structure and convenient use, can simulate various mining methods, freely adjust mining parameters, internally observe the broken form and the movement characteristics of the overlying strata, and provides basic data for the feasibility discrimination of subsequent upstream mining.

Description

Three-dimensional test device for simulating overburden rock movement characteristics under mining influence

Technical Field

The utility model relates to a three-dimensional test device for simulating the movement characteristics of overburden rock under the influence of mining, and belongs to the technical field of coal mining test research.

Background

In recent years, as the intensity of coal mining increases, coal resources under good mining conditions in many mining areas gradually decrease. The reserve of the left-over coal seam at the upper part of the residual mining area is considerable, and the method has good mining value, can relieve the problem of insufficient reserve of coal resources of part of the mining area, and effectively prolongs the mining life of the mining area. And the safety problems such as stability discrimination and the like in the upward mining process are increasingly prominent in the mining of the left coal seam at the upper part of the residual mining area due to the existence of the goaf at the lower part. In order to ensure the safe and orderly proceeding of the upward mining, the movement characteristics, the breaking range and the crack propagation penetration condition of the overburden caused by the lower coal seam mining need to be researched and analyzed.

Currently, the research on the movement rule of the overburden mainly includes four methods of field actual measurement (CN 103742127B, CN 103673982B, CN 104315988B, CN 107101617B and CN 105019888B), numerical simulation (CN 106884657B and CN 110018290A), physical simulation (CN 103489362B and CN 105403684B) and theoretical analysis (CN 103606019B, CN 110766293A, CN 105257337B and CN 108694272B). The field actual measurement method has long period, high cost and large influence by instruments and geological conditions; because of the limitation of software, the numerical simulation still has difficulty in truly and accurately calculating the stress and deformation states of the stope rock mass under the mining condition, so that the simulation result often cannot reflect the real mining state; the theoretical analysis mainly comprises a masonry beam theory, a transfer rock beam theory, a pressure arch hypothesis, a cantilever beam hypothesis, a hinged rock beam hypothesis and the like, and the hypotheses have corresponding hypothesis and application ranges and inaccurate phenomena on the movement and damage judgment of the overlying strata. And the physical similarity simulation test is a mainstream and efficient research means in the research field of mining engineering along with the perfection of the similarity theory and the simulation test technology. At present, most of the analogue simulation tests are two-dimensional simulation tests, the model boundary conditions are greatly simplified, the deformation damage of the overlying strata can only be observed on the surface, and the simulation results are often different from the actual conditions. The three-dimensional analogue simulation test can overcome a plurality of defects of the two-dimensional analogue simulation test, and the test result is more in line with the actual exploitation condition. However, most of the existing three-dimensional similar simulation tests have the problems that the exploitation parameters are single, the development condition of cracks in the model cannot be observed intuitively, and the same simulation platform cannot be suitable for various exploitation methods. Therefore, it is necessary to invent a test device which can freely adjust the exploitation parameters, observe the fracture form and the movement characteristics of the overburden inside and is suitable for various exploitation methods, and research the movement characteristics of the overburden after the working face is exploited.

Disclosure of Invention

The utility model aims to provide the three-dimensional test device which has a simple structure, is convenient to use, can simulate various mining methods, freely adjust mining parameters, internally observe the broken form and the movement characteristics of the overlying strata, and provides basic data for the feasibility discrimination of subsequent uplink mining.

According to the utility model, the actual stress state in the mining process of the ore body is simulated by adopting the three-way loading test device in a laboratory, the concrete mining parameters are regulated according to the mining method of the ore body, the actual mining process of the ore body is simulated, and the underground mine mining simulation visualization is realized by internally observing the fracture form and the movement characteristics of the overlying strata.

The utility model provides a three-dimensional test device for simulating the movement characteristics of overburden rock under the influence of mining, which comprises a loading device, a test box and a overburden rock movement monitoring device.

The loading device comprises a press machine support frame, a hydraulic cylinder, an oil pressure controller and a test box pressing plate; the support frame of the press machine forms an outer frame of the whole triaxial test device and comprises a top plate of the press machine, a bottom plate of the press machine and upright posts of the press machine; the upright posts of the press machine are connected with the top plate and the bottom plate of the press machine and are embedded and fixed on the ground to form stable and reliable connection; the hydraulic oil cylinder is fixed on the supporting frame of the press, one end of the hydraulic oil cylinder is connected with the oil pressure controller, the oil pressure controller provides oil pressure for the oil cylinder, the other end of the hydraulic oil cylinder is connected with the pressing plate of the test box, and confining pressure is provided for the test box; the test box pressing plate is arranged on the outer side (upper, left, right, front and back sides) of the test box body;

the test box comprises a box body and a coal stratum simulation device; wherein the box body comprises a rigid box body plate at the front, back, left and right and the upper part, and a flexible deformable angle plate connected with the rigid box body plate;

preferably, the side parts of the rigid box plate and the flexible deformable angle plate are respectively provided with a row of bolt holes, and the rigid box plate and the flexible deformable angle plate are connected through bolts;

preferably, the flexible deformable angle plate is made of one of a PVC high-hardness soft plate, an aluminum composite plate and a resin soft plate;

the coal stratum simulation device comprises a chassis, a vertical lifting rod, a small flat plate, a hinged ball, a hinged controller and a small hydraulic controller; wherein the chassis is a rectangular chassis made of a relatively rigid material, such as cast iron; the chassis is fixed on the bottom plate of the press; the vertical lifting rod is used for controlling the thickness of the simulated exploitation bottom plate and simulating the exploitation of the coal seam in different exploitation modes; the vertical lifting rod is fixed on the chassis and is connected with the small hydraulic controller, the pressure of the vertical lifting rod is controlled by the small hydraulic controller to realize vertical lifting, and the mining and filling of the coal bed and the supporting force of the post-mining hydraulic support are simulated; the vertical lifting rods are arranged in parallel and cover the whole chassis.

The vertical lifting rods and the small flat plates (each vertical lifting rod is connected with one small flat plate, when the small flat plate angle on each vertical lifting rod is parallel to the ground, the plane area of the small flat plate is approximately equal to the area of the chassis) are hinged through the hinge balls so as to control the angle between the small flat plate and the horizontal ground and simulate the stratum and the coal seam dip angle; the angle is adjustable: namely, controlling the angle between the small plate and the horizontal ground through the hinged controller; the angle of the hinging ball is controlled by the hinging controller, the small flat plate is welded on the hinging ball, and the angle formed by the small flat plate and the horizontal ground is controlled by controlling the angle of the hinging ball;

preferably, a row of bolt holes are formed in the peripheral edges of the chassis, and are connected with the flexible deformable corner plates through the bolt holes in a bolt manner, and the flexible deformable corner plates form a closed test box with the rigid box body plates at the front, the rear, the left and the upper parts;

preferably, the upper surface of the small flat plate is provided with a spring device, and the backfill condition of the filling body after the coal seam exploitation is simulated through the elasticity of the spring; the upper surface of the platelet is in contact with the formation because the weight of the formation is relatively large, the spring is always in compression when placed on the platelet, and the height of the spring is small, which is negligible compared to the thickness of the entire overburden.

The overlying strata 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 related data and stores and converts the data;

when rock stratum similar simulation materials are paved in a test box, a stress sensor is buried in the lower part of each layer of material, and stress change conditions of each layer of rock stratum before mining and in the mining process are monitored in real time through the stress sensor;

placing an acoustic emission sensor at the edge of a similar material of a pre-judging key layer in a test box, and monitoring acoustic emission signals and instantaneous elastic waves of the fracture of the overlying strata so as to determine the time and the position of the fracture of the strata;

the thermal infrared imaging instrument is erected outside the test box, the erection height is flush with the center position of the test box, and the thermal infrared imaging instrument is used for monitoring the displacement and deformation of the overburden before, during and after the coal seam exploitation so as to determine the fracture position and the occurrence time of the overburden;

the 3D laser scanner is used for panoramic scanning at each stratum laying stage and after the simulation test is finished so as to acquire the morphology of each stratum before and after exploitation, and 3D fracture reconstruction and numerical simulation calculation are carried out through image processing software and test data; the 3D laser scanner is erected on the movable support, a guide rail is arranged on the surface of the movable support, a sliding block is arranged in the guide rail, and the sliding block is connected with the 3D laser scanner through bolts and is used for moving and scanning of the 3D laser scanner; the movable support is not connected with the test box body, is movable equipment, and the height of the 3D laser scanner erected on the support is higher than the height of a rock and soil layer paved in the test box.

Preferably, a row of small holes are arranged in the vertical direction on the plane of the chassis, the small holes are used for enabling the miniature high-definition camera to enter the simulated goaf from the chassis, deformation and damage conditions of an overlying strata after various mining methods are adopted are observed in real time, and the formation and expansion processes of cracks are recorded. The miniature high-definition camera is similar to a probe, can enter the test box from the small hole, and is not fixed on the chassis.

The utility model provides a three-dimensional test method for simulating the movement characteristics of overburden rock under the influence of mining, which comprises the following specific steps:

(1) Selecting an actual ore body exploitation test simulation range, testing physical and mechanical parameters of stratum coal and rock in the range, selecting sand, gypsum, lime and cement similar simulation materials similar to the actual ore body according to a similar simulation principle, and determining test amounts of various materials;

(2) Bolt connection is formed between the flexible deformable corner plates and the bolt holes at the peripheral edges of the chassis, and the flexible deformable corner plates are connected with the front, back, left and right rigid box body plates to form a test box with sealed periphery;

(3) According to the thickness and the inclination angle of the coal seam of the simulated mining working face, the height of the vertical lifting rod and the angle of the hinge ball are adjusted through the hydraulic controller and the hinge controller, so that the height of the vertical lifting rod is equal to the similar simulated height of the actual coal seam thickness, and the angle of the hinge ball is consistent with the inclination angle of the actual coal seam;

(4) Mixing the various similar simulation materials calculated in the step (1) according to the actual parameters of each stratum, and uniformly paving the mixed materials on a simulation working surface bottom plate consisting of a vertical lifting rod and a small plate in a test box according to layers; the method comprises the steps of installing stress sensors at the lower part of each stratum in the process of laying similar materials of each stratum, and placing acoustic emission sensors at the edges of the similar materials of a pre-judging key layer; carrying out panoramic scanning on each layer of stratum after the similar materials are paved by using a 3D laser scanner (the surface of each layer of stratum after the pavement is paved is scanned without photographing the whole process) so as to obtain the morphology of each stratum before mining, and reconstructing a numerical model of a similarity simulation test before mining by using an image processing software;

according to different mining methods, the stress sensors are arranged with a plurality of measuring lines along the trend or trend of the rock stratum, the distance between each measuring line is 25+/-5 cm, each measuring line is provided with 3-6 stress sensors, the distance between each stress sensor is 25+/-5 cm, and the stress change conditions of each stratum stress before coal mining and each arrangement point in the coal mining process are monitored and collected in real time through each stress sensor;

the acoustic emission sensor is arranged at the edge of a similar material of a pre-judging key layer in the test box and is 20+/-3 cm away from the edge of the test box body, and acoustic emission signals of the fracture of the overlying strata are monitored and collected in real time;

(5) After the similar material of the rock stratum to be tested is simulated to be dry and hard, scanning the rock stratum at the uppermost layer by using a 3D laser scanner, covering the rock stratum at the upper part of the test box with a rigid box plate, and connecting and fixing the rigid box plate at the upper part of the test box with a flexible deformable angle plate by using bolts to form a complete test box;

(6) Starting a loading device, and applying pressure to a test box by a hydraulic oil cylinder through a test box pressing plate until the three-dimensional (three directions are simultaneously loaded, wherein the three directions refer to three directions of x, y and z, namely front and back, left and right, up and down) loading pressure reaches a preset value, and the preset value is the actually measured ground stress of a simulated exploitation stratum; the loading process should be carried out simultaneously, the three-dimensional stress loading rate is constant, the coordination is kept, and the pressure control point is reached as simultaneously as possible; recording the stress measured by each stress sensor after loading is finished; starting a 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, a small hydraulic controller and a hinged controller are used for controlling the up-and-down movement of a plurality of vertical lifting rods on a chassis and the inclination angle of a small plate, so that coal seam mining is accurately simulated; by coordinately controlling whether each vertical lifting rod descends, the descending height and speed, lifting the height and speed after descending, and the like, various working conditions with different mining heights, mining widths and working face propelling speeds and mining methods are simulated;

in the test process, a miniature high-definition camera enters the goaf range in the test box through a small hole of a chassis, deformation and damage conditions of an overlying strata after various mining methods and various working conditions are observed in real time, and the formation and expansion processes of cracks are recorded;

in addition, stress sensor, acoustic emission sensor, thermal infrared imager of the monitoring device of the movement of overlying strata in the test process monitor stress, deformation and breaking parameter of the rock stratum in real time and record;

(8) After the simulated excavation is finished, removing the peripheral pressure of the test box and removing the rigid box body plate at the upper part of the test box; the model materials are cleaned layer by layer along the layer surface from top to bottom, a 3D laser scanner is used for panoramic scanning before each layer of cleaning to obtain the surface morphology of the layer, and a high-definition camera is used for recording the whole layer by layer cleaning process so as to record the profile change condition of the model; 3D fracture reconstruction and numerical simulation calculations are performed by image processing software in combination with test trial data.

The utility model has the beneficial effects that:

(1) According to the utility model, different fluctuation conditions of a coal stratum are simulated by adjusting the height of the vertical lifting rod and the angle between the small flat plate and the horizontal plane, the descending height and the descending speed are controlled, and the height and the descending speed are improved after the vertical lifting rod descends, so that the mining height, the mining width and the mining speed of a working face are different from those of manual excavation in the traditional similar simulation test, various working conditions such as hydraulic support after mining or stope backfill and the like and mining methods can be accurately controlled, a model test box body is not required to be removed, disturbance of the outside on the simulated stratum is reduced, and the precision and the reliability of test results are improved; meanwhile, stress loading is carried out in the three-dimensional direction of the test box, so that the stress state and deformation condition of the coal rock mass in the mining process can be truly simulated;

(2) According to the utility model, before the actual exploitation of the simulated working face, the stress state and the deformation condition of the model before the exploitation of the working face are obtained by utilizing the monitoring instruments such as a stress sensor, a thermal infrared imager and a 3D laser scanner in the overlying strata motion monitoring device, the initial stress state and the model form of the model are monitored, and the method is different from the traditional simulation test which only monitors the deformation and the cracking condition of the overlying strata during and after the exploitation, has more complete test data and larger information quantity, and provides a data basis for researching the fracture and the motion characteristics of the overlying strata under the influence of the exploitation in the front, middle and later stages of exploitation;

(3) According to the utility model, the miniature high-definition camera enters the simulated goaf, deformation and damage conditions of the overlying strata after various mining methods are observed in real time, and the formation and expansion processes of cracks are recorded, so that the method is different from the traditional simulation test which only can observe deformation conditions of various strata on the surface of a model, can more accurately master deformation and crack conditions in the rock after mining, and provides a basis for stability analysis of the later overlying strata;

(4) The utility model forms the closed test box by connecting the front, back, left and right and upper rigid box plates through the flexible deformable corner plates, which is beneficial to preventing the rigid box plates from extruding each other in the confining pressure loading process and ensuring the smooth loading of triaxial confining pressure.

Drawings

FIG. 1 is a schematic structural diagram of a three-dimensional test device for simulating the movement characteristics of overburden rock under the influence of mining;

FIG. 2 is a schematic diagram of a test chamber body;

FIG. 3 is a schematic diagram (isometric view) of a test chamber coal formation simulation apparatus;

FIG. 4 is a schematic diagram of a 3D laser scanner movable support;

in the figure: the device comprises a press bottom plate 1, a press top plate 2, a press upright post 3, a ground 4, a hydraulic cylinder 5, a test box pressing plate 6, a rigid box plate 7, a flexible deformable angle plate 8, a bolt 9, a chassis 10, a vertical lifting rod 11, a small flat plate 12, a hinged ball 13, a miniature high-definition camera 14, a 3D laser scanner 15, a guide rail 16, a slide block 17, a hydraulic controller 18, a stress sensor 19, an acoustic emission sensor 20, a data acquisition processor 21, a thermal infrared imager 22, a box 23, a small hydraulic controller 24, a hinged controller 25 and a high-definition camera system 26.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1-4, the three-dimensional test device for simulating the characteristics of the movement of the overburden rock under the influence of mining provided by the utility model comprises a loading device, a test box and a movement monitoring device of the overburden rock.

The loading device comprises a press supporting frame, a hydraulic oil cylinder 5, an oil pressure controller 18 and a test box pressing plate 6. The support frame of the press machine forms an outer frame of the whole triaxial test device and comprises a press machine top plate 2, a press machine bottom plate 1 and a press machine upright post 3; the press upright post 3 is connected with the press top plate 2 and the press bottom plate 1 and is embedded and fixed on the ground to form stable and reliable connection; the test box is positioned in the support frame of the press, the test box pressing plate 6 is arranged outside the test box, and the hydraulic cylinder 5 is uniformly connected outside the test box pressing plate 6; one end of the hydraulic cylinder 5 is fixed on the supporting frame of the press machine and is connected with the oil pressure controller 18 to provide oil pressure, and the other end of the hydraulic cylinder is fixed on the pressing plate 6 of the test box to provide confining pressure for the test box.

The test box comprises a box body and a coal stratum simulation device. Wherein, the box body is connected into a whole by bolts 9 with a front, a back, a left, a right and an upper rigid box body plate 7 with a row of bolt holes at the edge and a flexible deformable angle plate 8 connected with the rigid box body plate 7 to form a box body with a cubic structure. The flexible deformable corner plate 8 is made of PVC soft board with high hardness. The layered structure seen in fig. 1 is achieved by laying the rock strata of different materials.

The coal stratum simulation device consists of a chassis 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; wherein the chassis is a rectangular chassis with the length of 2m multiplied by 1m made of cast iron, and the lower end of the chassis is fixed on the bottom plate 1 of the press. The periphery of the chassis is respectively provided with a row of bolt holes, and the bolt holes are connected with the flexible deformable corner plates 8 through bolts, and form a closed cube test box with the rigid box body plates 7 at the front, rear, left, right and upper parts; the test chamber coal formation simulator shown in fig. 3 is a diagonally downward view in fig. 1.

The vertical lifting rod 11 is fixed on the upper part of the chassis 10 and is connected with the small hydraulic controller 24, and the vertical lifting height of the vertical lifting rod 11 and the pressure in the vertical lifting rod are controlled by the small hydraulic controller 24 to simulate the exploitation and filling of a coal bed and the supporting force of a post-exploitation hydraulic bracket. The upper part of the vertical lifting rod 11 is hinged with a small plate 12 with the length of 5cm multiplied by 5cm through a hinging ball 13, the hinging ball 13 controls the angle between the small plate 12 and the horizontal ground through a hinging controller 25, and the stratum and the coal seam dip angle are simulated.

Preferably, the upper surface of the small flat plate 12 is provided with a spring device, and the backfill condition of the filling body after the coal seam mining is simulated by the elastic force of the spring. Namely: when the ore body is simulated to be filled, the height of the vertical lifting rod 11 can be regulated and controlled firstly, the backfill height of the filling body is determined, meanwhile, as the prior art does not have a method for completely attaching the filling body to the overlying strata to provide enough supporting force, at the moment, the pressure on the spring is released and is not in a compressed state, a certain supporting effect can be achieved on the overlying strata, and strong supporting force is not provided, so that the backfill condition of the ore body is simulated.

The overlying strata movement monitoring device comprises 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.

When the rock stratum similar simulation materials are paved in the test box, a stress sensor 19 is buried in the lower part of each layer of material, meanwhile, an acoustic emission sensor 20 is placed at the edge of the similar material of the pre-judging key layer, stress change conditions of each rock stratum before and during mining and acoustic emission signals of rock stratum fracture are monitored, and the time and the position of the rock stratum fracture are determined.

The thermal infrared imager 22 is erected outside the test box at the same height as the center of the test box, and is used for monitoring the displacement and deformation of the overburden before, during and after the coal seam exploitation to determine the overburden breaking position and occurrence time.

The 3D laser scanner 15 is used for panoramic scanning at each stratum laying stage and after the simulation test is finished, so as to obtain the morphology of each stratum before and after exploitation, and perform 3D fracture reconstruction and numerical simulation calculation through image processing software and test data. The 3D laser scanner 15 is arranged on a movable support, a guide rail 16 is arranged on the movable support, a sliding block 17 is arranged in the guide rail 16, and the sliding block 17 is connected with the 3D laser scanner 15 through bolts and used for moving and scanning the 3D laser scanner 15. As shown in fig. 4, the movable support is a stand alone device that moves over the test chamber when scanning is desired, moves the 3D laser scanner into an unloaded space, and moves out when scanning is not desired.

A row of small holes are arranged in the vertical direction on the plane of the chassis 10 and used for enabling the miniature high-definition camera 14 to enter the simulated goaf from the chassis 10, observing deformation and damage conditions of an overlying strata after various mining methods are mined in real time, and recording the formation and expansion processes of cracks;

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 related data and stores and converts the data.

The three-dimensional test method for simulating the characteristics of the overburden rock movement under the influence of mining provided by the embodiment has the following simulation working conditions: the working face is used for mining No. 22 coal beds, the average inclination angle of the coal beds is 4 degrees, and the average thickness of the coal beds is 3.15m. The direct roof is fine sandstone with the thickness of 2.27m, the old roof is middle sandstone with the thickness of 12.78m; sand mudstone, 16.48m. And a No. 19 coal bed is covered, the thickness of the No. 19 coal bed is 2m, the direct roof of the No. 19 coal bed is fine sandstone, the thickness of the old roof is medium fine sandstone, and the thickness of the old roof is 8.72m. There are 1 faults with a drop of 1.6m across the face, 300m from the face of the cut. The gas content of the coal is low. The working face adopts a long wall caving coal mining method, the average mining height is 3.15m, the working face is 150m long, and the trend length is 1000m. The working face adopts four-shift system, three-shift production, one-shift maintenance and daily footage 13.5m.

The specific test steps are as follows:

(1) According to the simulation working conditions, physical and mechanical parameters of each coal bed and each rock stratum in the working condition range are tested, sand, gypsum and lime are determined to be selected similar simulation materials, and the test dosage of each material is determined, and is shown in table 1.

TABLE 1 physical and mechanical parameters of each coal and rock stratum and similar simulated material usage

(2) And (3) bolting the rectangular chassis with the length of 2m multiplied by 1m with the flexible deformable corner plates through bolt holes at the peripheral edges of the chassis, and connecting the flexible deformable corner plates with the front, back, left and right rigid box body plates with the height of 1.5m to form the cubic test box with the periphery sealed.

(3) And according to the thickness and the inclination angle of the coal seam of the working face of the simulated working condition exploitation, the height of the vertical lifting rod at the left side of the fault is adjusted to 9.45cm, the height of the vertical lifting rod at the right side of the fault is adjusted to 14.28cm, and the angle of the small flat plate is 4 degrees through a hydraulic controller and a hinged controller.

(4) Mixing the various similar simulation materials calculated in the step (1) according to a proportion, and uniformly paving the materials on a simulation working surface bottom plate consisting of a vertical lifting rod and a small plate in a test box according to a layer. In the process of laying similar materials of all strata, 3 measuring lines are arranged at the lower part of each stratum along the stratum trend (the width direction of a test box), the distance between the measuring lines is 30cm, 6 stress sensors are arranged on each measuring line, the distance between the stress sensors is 30cm, and the stress of all strata before coal mining and the stress change condition of all arrangement points in the coal mining process are monitored. And placing an acoustic emission sensor in the position 20cm away from the edge of the test box in the similar material pre-judging key layer, and monitoring and collecting acoustic emission signals of the fracture of the overlying strata in real time. And simultaneously, carrying out panoramic scanning on each stratum layer paved with similar materials by using a 3D laser scanner so as to acquire the morphology of each stratum before mining, and reconstructing a numerical model of a pre-mining similarity simulation test by using an image processing software.

(5) After the similar material of the rock stratum to be tested is simulated to be dry and hard, scanning the rock stratum at the uppermost layer by using a 3D laser scanner, covering the rock stratum at the upper part of the test box with a rigid box plate at the upper part of the test box, and connecting and fixing the rigid box plate at the upper part of the test box with a flexible deformable angle plate by using bolts to form a complete and closed cube test box;

(6) And starting the loading device, and simultaneously applying pressure to the test box by the hydraulic oil cylinder through the test box pressing plate at a constant loading rate until the three-way loading pressure reaches the actually measured ground stress of the simulated exploitation stratum. And after loading, recording the stress measured by each stress sensor, and starting a thermal infrared imager to record the initial state of each simulated rock stratum before coal mining.

(7) The simulation working condition adopts a longwall caving coal mining method, positions of a first row of vertical lifting rods, a second row of vertical lifting rods and a small flat plate which are closest to a front rigid box body plate are kept unchanged, and ore pillars between two stopes are simulated; firstly, descending the third, fourth, fifth, sixth … … thirteen and fourteen rows of vertical lifting rods of the first row from front to back in sequence, wherein the descending speed is 0.21cm/min; secondly, after the first row of vertical lifting rods completely descends to the original position, the third row, the fourth row, the fifth row, the sixth row, the … …, the thirteenth row and the fourteen row of vertical lifting rods of the second row are sequentially descended from front to back, wherein the descending speed is 0.21cm/min; the third and fourth columns … … are then lowered sequentially from front to back until the face mining is completed.

In the test process, a miniature high-definition camera enters the goaf range in the test box through a small hole of the chassis, deformation and damage conditions of an overlying strata after exploitation are observed in real time, and the formation and expansion processes of cracks are recorded.

In addition, stress sensor, acoustic emission sensor, thermal infrared imager of overburden motion monitoring devices in the test process real-time supervision stratum stress, deformation and broken parameter and record.

(8) And after the simulated excavation is finished, removing the peripheral pressure of the test box and removing the rigid box body plate at the upper part of the test box. And cleaning model materials layer by layer along the layers from top to bottom, wherein before each layer of model materials is cleaned, a 3D laser scanner is used for panoramic scanning so as to obtain the surface morphology of the rock stratum, and meanwhile, a high-definition camera is used for recording the whole layer by layer cleaning process so as to record the profile change condition of the model. And then carrying out 3D fracture reconstruction and numerical simulation calculation by using image processing software and combining test data.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (7)

1. The three-dimensional test device for simulating the movement characteristics of the overburden rock under the influence of mining is characterized by comprising a loading device, a test box and a overburden rock movement monitoring device;

the loading device comprises a press machine support frame, a hydraulic cylinder, an oil pressure controller and a test box pressing plate; the support frame of the press machine forms an outer frame of the whole triaxial test device and comprises a top plate of the press machine, a bottom plate of the press machine and upright posts of the press machine; the upright post of the press machine is connected with the top plate and the bottom plate of the press machine and is embedded and fixed on the ground; the hydraulic oil cylinder is fixed on the supporting frame of the press, one end of the hydraulic oil cylinder is connected with the oil pressure controller, the oil pressure controller provides oil pressure for the oil cylinder, the other end of the hydraulic oil cylinder is connected with the pressing plate of the test box, and confining pressure is provided for the test box; the test box pressing plate is arranged on the outer side surface of the test box body;

the test box comprises a box body and a coal stratum simulation device; wherein the case comprises front, rear, left, right and upper rigid case plates and flexible deformable corner plates connecting the rigid case plates;

the coal stratum simulation device comprises a chassis, a vertical lifting rod, a small flat plate, a hinged ball, a hinged controller and a small hydraulic controller; wherein the chassis is a rectangular chassis made of a material with high rigidity and is fixed on a bottom plate of the press; the vertical lifting rod is used for controlling the thickness of the simulated exploitation bottom plate and simulating the exploitation of the coal seam in different exploitation modes; the vertical lifting rod is fixed on the chassis and is connected with the small hydraulic controller, the pressure of the vertical lifting rod is controlled by the small hydraulic controller to realize vertical lifting, and the mining and filling of the coal bed and the supporting force of the post-mining hydraulic support are simulated; the vertical lifting rods are arranged in parallel and cover the whole chassis; the vertical lifting rod is hinged with the small flat plate through a hinging ball so as to control the angle between the small flat plate and the horizontal ground and simulate the stratum and the coal seam dip angle;

the overlying strata 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 related data and stores and converts the data; when rock stratum similar simulation materials are paved in a test box, a stress sensor is buried in the lower part of each layer of material, and stress change conditions of each layer of rock stratum before mining and in the mining process are monitored in real time through the stress sensor; placing an acoustic emission sensor at the edge of a similar material of a pre-judging key layer in a test box, and monitoring acoustic emission signals and instantaneous elastic waves of the fracture of the overlying strata so as to determine the time and the position of the fracture of the strata; the thermal infrared imaging instrument is erected outside the test box, the erection height is flush with the center position of the test box, and the thermal infrared imaging instrument is used for monitoring the displacement and deformation of the overburden before, during and after the coal seam exploitation so as to determine the fracture position and the occurrence time of the overburden; the 3D laser scanner is used for panoramic scanning at each stratum laying stage and after the simulation test is finished; the miniature high-definition camera is arranged in the test box body above the chassis and used for monitoring deformation and damage conditions of the overlying strata.

2. The three-dimensional test device for simulating the movement characteristics of overburden under the influence of mining according to claim 1, wherein: the side parts of the rigid box body plate and the flexible deformable angle plate are respectively provided with a row of bolt holes, and the rigid box body plate and the flexible deformable angle plate are connected through bolts; the flexible deformable angle plate is made of one of a PVC high-hardness soft plate, an aluminum composite plate and a resin soft plate.

3. The three-dimensional test device for simulating the movement characteristics of overburden under the influence of mining according to claim 1, wherein: each vertical lifting rod is connected with a small flat plate, and the angle between the small flat plate and the horizontal ground is controlled by the hinge controller; the angle of the hinging ball is controlled by the hinging controller, the small flat plate is welded on the hinging ball, and the angle formed by the small flat plate and the horizontal ground is controlled by controlling the angle of the hinging ball.

4. The three-dimensional test device for simulating the movement characteristics of overburden under the influence of mining according to claim 1, wherein: a row of bolt holes are formed in the periphery of the chassis, the bolt holes are connected with the flexible deformable corner plates through bolts, and the chassis is formed into a closed test box with the front, the rear, the left, the right and the upper parts of the chassis.

5. The three-dimensional test device for simulating the movement characteristics of overburden under the influence of mining according to claim 1, wherein: the upper surface of the small flat plate is provided with a spring device, and the backfill condition of the filling body after the coal seam exploitation is simulated through the elasticity of the spring; the upper surface of the plate is in contact with the rock strata because the rock strata are relatively heavy and the springs are always in compression when placed on the plate.

6. The three-dimensional test device for simulating the movement characteristics of overburden under the influence of mining according to claim 1, wherein: the 3D laser scanner acquires the shape of each rock stratum before and after exploitation, and performs 3D fracture reconstruction and numerical simulation calculation through image processing software and test data; the 3D laser scanner is erected on the movable support, a guide rail is arranged on the surface of the movable support, a sliding block is arranged in the guide rail, and the sliding block is connected with the 3D laser scanner through bolts and is used for moving and scanning of the 3D laser scanner; the movable support is not connected with the test box body, is movable equipment, and the height of the 3D laser scanner erected on the support is higher than the height of a rock and soil layer paved in the test box.

7. The three-dimensional test device for simulating the movement characteristics of overburden under the influence of mining according to claim 1, wherein: a row of small holes are arranged in the vertical direction on the plane of the chassis and used for enabling the miniature high-definition camera to enter the simulated goaf from the chassis, observing deformation and damage conditions of an overlying strata after various mining methods are mined in real time, and recording the formation and expansion processes of cracks.

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