Gob-side entry retaining three-dimensional mining test system suitable for fault-containing structure

Abstract

The invention discloses a gob-side entry retaining three-dimensional mining test system suitable for a fault-containing structure, and mainly relates to the technical field of coal mining tests. Comprising a geologic model, a simulation excavation assembly, a pumping system and a pressurization system. The geologic model comprises a fault hanging wall and a fault footwall, and each of the fault hanging wall and the fault footwall comprises a rock stratum above a coal seam and a rock stratum below the coal seam; a plurality of simulated excavation assemblies are arranged between the rock stratum above the coal seam and the rock stratum below the coal seam, each simulated excavation assembly comprises a liquid storage box, a guide pipe and a sample plate, and the dissolving liquid is used for dissolving the sample plates; the pumping system comprises a rack, a liquid storage tank and a hydraulic cylinder are sequentially arranged on the rack from bottom to top, the bottom of the liquid storage tank is communicated with the guide pipe through a connecting pipe, a piston structure is arranged in the liquid storage tank, and the bottom end of a piston rod of the hydraulic cylinder is inserted into the liquid storage tank and fixedly connected with the piston structure; the method can achieve the purpose of simulating working cross-fault continuous mining.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining experiments, and specifically to a three-dimensional mining experiment system for gob-side entry retaining applicable to fault structures. Background Art

[0002] With the continuous growth of coal demand, coal mines are constantly increasing their production capacity, which makes the excavation range and speed of the working face faster. Correspondingly, the probability of surrounding rock instability is also rising. Among them, special geological areas such as fault-affected areas are extremely vulnerable to influence. In the fault structure area, the rock mass is in a fragmented state and the lithology is diverse. This not only causes the mechanical properties of the rock to vary greatly, but also forms potential sliding surfaces inside the fault. During the coal mining process, the stress redistribution caused by coal mining will trigger relative displacement along the fault plane, which may release a large amount of stored energy, leading to serious rock burst accidents and roadway collapses.

[0003] In the exploration of the surrounding rock deformation mechanism of gob-side entry retaining under the influence of faults, the following research methods are usually adopted: Theoretical research is generally based on a series of simplified assumptions about boundary conditions, which may not fully reflect the complexity of the actual geological scenario; Although numerical simulation is powerful, due to the lack of a perfect constitutive model, it is difficult to accurately present the complex non-linear behavior of rocks; Conducting on-site tests requires a large amount of cost in terms of time, manpower and resources, and it is often difficult to obtain comprehensive and accurate results. In contrast, physical model testing scales down the actual geological environment, and can truly simulate the deformation and failure modes of the surrounding rock of gob-side entry retaining under the influence of faults under stress. This method provides a direct and intuitive way to understand the potential deformation mechanism, and also provides valuable insights for optimizing the support strategy and ensuring safe mining operations.

[0004] However, in traditional two-dimensional geomechanical model tests, for gob-side entry retaining working faces with fault structures, the method of artificially damaging the rock mass can be used to simulate coal seam excavation. However, in three-dimensional geomechanical model tests, due to the long dimensions in three dimensions and the elevation difference between the hanging wall and the footwall of the fault, the traditional method of damaging the rock mass for excavation is no longer applicable. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art, and in view of the requirements of the existing three-dimensional geomechanical model test system, to provide a three-dimensional mining experiment system for gob-side entry retaining applicable to fault structures, so as to achieve the purpose of simulating continuous mining across faults.

[0006] To achieve the above object, the present invention is realized through the following technical solutions:

[0007] A three-dimensional mining test system applicable to gob-side entry retaining with fault structures, including a geological model, a simulated excavation component, a pumping system, and a pressurizing system; the geological model includes a hanging wall of the fault and a footwall of the fault, and the contact surface between the hanging wall of the fault and the footwall of the fault is the fault contact surface. Both the hanging wall of the fault and the footwall of the fault include the strata above the coal seam and the strata below the coal seam; several simulated excavation components are arranged between the strata above the coal seam and the strata below the coal seam. The simulated excavation component includes a liquid storage box with an open top, a conduit for filling the liquid storage box with a dissolving liquid, and a test sample plate for closing the open top of the liquid storage box. The dissolving liquid is used to dissolve the test sample plate; the pumping system includes a frame, on which a liquid storage tank and a hydraulic cylinder are successively arranged from bottom to top. The bottom of the liquid storage tank is communicated with the conduit through a connecting pipe. The liquid storage tank is used to store the dissolving liquid. A piston structure is arranged in the liquid storage tank. The bottom end of the piston rod of the hydraulic cylinder is inserted into the liquid storage tank and fixedly connected with the piston structure; the pressurizing system is used to provide hydraulic oil for the hydraulic cylinder and control the telescopic movement of the hydraulic cylinder.

[0008] Preferably, the dissolving liquid is a polar organic solvent, and the test sample plate is a foam board.

[0009] Preferably, the test sample plate is horizontally inlaid in the liquid storage box.

[0010] Preferably, a simulated coal pillar is arranged between the strata above the coal seam and the strata below the coal seam.

[0011] Preferably, a roadway for the connecting pipe to enter is reserved between the strata above the coal seam and the strata below the coal seam.

[0012] Preferably, a control valve is arranged at the connection between the connecting pipe and the liquid storage tank.

[0013] Preferably, the connecting pipe is detachably connected to the control valve.

[0014] Preferably, the control valve is provided with a quick-release joint for connecting with the connecting pipe.

[0015] Preferably, the pressurizing system includes a hydraulic servo control system and a hydraulic oil pipe for delivering hydraulic oil to the hydraulic cylinder.

[0016] Preferably, hydraulic oil inlets and outlets are arranged at both the upper and lower ends of the outer wall of the cylinder body of the hydraulic cylinder.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. The present invention uses the principle of dissolving the test sample plate with a dissolving liquid to replace the traditional manual destruction of rock mass to achieve the purpose of truly simulating the mining of the working face of gob-side entry retaining across the fault by roof cutting.

[0019] 2. The pumping system, pressurizing system and simulated excavation assembly of the present invention can restore the mining of the cross-fault cutting top into the lane working face to the maximum extent without affecting the collapse of the rock mass above the lagging working face, effectively solving the problem that the traditional three-dimensional geomechanical model test cannot simulate the mining of the fault collapse.

[0020] 3. The excavation method of dissolving the sample plate with a dissolving liquid adopted in the present invention solves the problem that the traditional artificial destruction of rock mass and strip extraction methods will generate stress disturbances, which in turn will affect the test monitoring data.

[0021] 4. The simulated excavation assembly of the present invention cooperates with the pumping system to realize continuous mining of the working face, improve the excavation efficiency of the working face, and avoid the stress lag problem caused by intermediate time delays. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a schematic diagram of the arrangement of the simulated excavation components;

[0024] Figure 3 It is a schematic diagram of the structure of the simulated excavation component;

[0025] Figure 4 It is a structural diagram of the pumping system.

[0026] Numbers in the attached drawings: 1. Geological model; 11. Hanging wall of fault; 12. Footing wall of fault; 13. Fault contact surface; 14. Rock layer above the coal seam; 15. Rock layer below the coal seam; 16. Simulated coal pillar; 17. Tunnel; 2. Simulated excavation component; 21. Liquid storage box; 22. Conduit; 23. Sample plate; 3. Pumping system; 31. Frame; 32. Liquid storage tank; 33. Hydraulic cylinder; 34. Connecting pipe; 35. Piston structure; 36. Control valve; 37. Hydraulic oil inlet and outlet; 4. Pressurization system; 41. Hydraulic servo control system; 42. Hydraulic oil pipe. DETAILED DESCRIPTION

[0027] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the application equally.

[0028] Example: As shown in the attached Figure 1-4 As shown, the present invention is a three-dimensional mining test system suitable for gob-side entry retention in fault structures, including a geological model 1, a simulated excavation component 2, a pumping system 3, and a pressurizing system 4.

[0029] The geological model 1 includes the hanging wall 11 of the fault and the footwall 12 of the fault. The contact surface between the hanging wall 11 of the fault and the footwall 12 of the fault is the fault contact surface 13. Both the hanging wall 11 of the fault and the footwall 12 of the fault include the strata above the coal seam 14 and the strata below the coal seam 15.

[0030] A number of simulated excavation components 2 are provided between the strata above the coal seam 14 and the strata below the coal seam 15. The simulated excavation components 2 are installed above the strata below the coal seam 15 to simulate the coal seam and support the strata above the coal seam 14.

[0031] The simulated excavation component 2 includes a liquid storage box 21 with an open top, a conduit 22 for filling the liquid storage box 21 with a dissolving liquid, and a test sample plate 23 for closing the open top of the liquid storage box 21. The dissolving liquid is used to dissolve the test sample plate 23, and the excavation simulation of the coal seam is realized based on the principle that the dissolving liquid can melt the test sample plate 23.

[0032] Among them, the dissolving liquid can be a polar organic solvent (such as acetone solution), the test sample plate 23 can be made of low-density polyethylene or foam board, and preferably high-strength foam board; the dissolving liquid can also be an acidic solvent (such as sulfuric acid mixture), and the test sample plate 23 can be made of PET plastic material.

[0033] Preferably, the test sample plate 23 is horizontally embedded in the liquid storage box 21.

[0034] The pumping system 3 includes a frame 31. A liquid storage tank 32 and a hydraulic cylinder 33 are successively arranged on the frame 31 from bottom to top. The bottom of the liquid storage tank 32 is communicated with the conduit 22 through a connecting pipe 34. The liquid storage tank 32 is used to store the dissolving liquid. A piston structure 35 is arranged in the liquid storage tank 32 above the dissolving liquid. The bottom end of the piston rod of the hydraulic cylinder 33 is inserted into the liquid storage tank 32 and fixedly connected with the piston structure 35. The pumping system 1 is placed outside the entire geological model 1 and connected to the conduit 22 through the connecting pipe 34 to convey the dissolving liquid to the liquid storage box 21.

[0035] The pressurizing system 4 is used to provide hydraulic oil for the hydraulic cylinder 33 and control the expansion and contraction of the hydraulic cylinder 33.

[0036] Preferably, a simulated coal pillar 16 is provided between the strata above the coal seam 14 and the strata below the coal seam 15.

[0037] Preferably, a roadway 17 for the connecting pipe 34 to enter is reserved between the strata above the coal seam 14 and the strata below the coal seam 15.

[0038] Specifically, the entire coal seam to be simulated excavated is composed of several sets of simulated excavation assemblies 2. Each liquid reservoir 21 in the simulated excavation assemblies 2 has a conduit 22 outlet for releasing a solution (such as an acetone solution). The liquid reservoir 21 can be welded from 1mm thick alloy plates. It does not bear pressure, but only stores the solution. The sample plate 23 (such as a high-strength foam board) must be sized to match the size of the liquid reservoir 21 and must be the same as the internal dimensions of the liquid reservoir 21. When designing the experiment, the dimensions of the liquid reservoir 21 and sample plate 23, as well as their connection method, can be adjusted according to specific experimental requirements. One embodiment is as follows: the entire geological model 1 has dimensions of 1100mm×1100mm×1100mm, the coal seam of the fault footwall 12 is 280mm from the bottom of the model, the coal seam of the fault hanging wall 11 is 200mm from the bottom of the model, and the width of the tunnel 17 is 100mm. To meet the design requirements of this experiment, each simulated excavation assembly 2 is equipped with four fluid reservoirs 21 and four conduits 22. This allows for four excavation steps for every 100mm of working face advance. The length and width of the fluid reservoirs 21 and sample plates 23 can be customized to meet experimental requirements, enabling simulated coal seam excavation under a variety of parameters.

[0039] Preferably, a control valve 36 is provided at the connection point between each connecting pipe 34 and the liquid storage tank 32 to control the delivery of the dissolved liquid.

[0040] Preferably, the connecting pipe 34 and the control valve 36 are detachably connected to simulate group excavation.

[0041] Preferably, the control valve 36 is provided with a quick-release connector for connecting to the connecting pipe 34 , which can facilitate the disassembly and assembly of the connecting pipe 34 .

[0042] Preferably, the pressurizing system 4 includes a hydraulic servo control system 41 and a hydraulic oil pipe 42 for delivering hydraulic oil to the hydraulic cylinder 33 .

[0043] Preferably, hydraulic oil inlets and outlets 37 are provided at the upper and lower ends of the outer wall of the cylinder body of the hydraulic cylinder 33 .

[0044] When the present invention is in use, after the rock layer 15 below the coal seam is built, the simulated excavation component 2 needs to be installed on the right side of the tunnel 17. During installation, a width of 100 mm of the tunnel 17 needs to be reserved to place the conduit 22; the conduit 22 needs to pass through the liquid storage box 21, so a sealing strip needs to be used to seal the gap between the conduit 22 and the liquid storage box 21 to prevent the dissolved liquid from leaking, thereby affecting the test results.

[0045] After installing the simulated excavation components of the fault hanging wall 11 and the fault footwall 12, Figure 2As shown in the figure, the conduits 22 led out from each simulated excavation component 2 are numbered. Capital letters (A - I) are used to represent each set of excavation components, and Arabic numerals (1 - 4) are used to represent each excavation (each liquid storage box 21).

[0046] After completing the above work, the remaining part of the geological model 1 needs to be built above the simulated coal pillar 16 and the test sample plate 23.

[0047] Then connect the pumping system 3 to the simulated excavation component 2.

[0048] Then connect the pumping system 3 to the pressurizing system 4.

[0049] After all the devices are installed, first close the control valve 36, then control the hydraulic cylinder 33 through the hydraulic servo control system 41 to lift the piston structure 35 in the liquid storage tank 32 above the mouth of the liquid storage tank 32, and then introduce the dissolving liquid into the liquid storage tank 32 to complete the preparation work.

[0050] After completing all the preparation work, turn on the hydraulic servo control system 41 and control the pressure in the liquid storage tank 32 at 0.5 Mpa.

[0051] Open the switches corresponding to the A - 1, A - 2, A - 3, and A - 4 liquid storage boxes 21 in sequence. At this time, the dissolving liquid in the liquid storage tank 32 enters the liquid storage box 21 through the connecting pipe 34 and the conduit 22. When the dissolving liquid encounters the test sample plate 23, a chemical reaction starts between the two, and the test sample plate 23 begins to be gradually dissolved by the dissolving liquid. At this time, the excavation of 100 mm (the width corresponding to the A excavation component) is completed.

[0052] After all the test sample plates 23 in group A are fully dissolved, close the control valve 36, then connect the connecting pipe 34 corresponding to the conduit 22 of group B to the control valve 36, and then carry out the excavation of group B.

[0053] Dissolve the test sample plates 23 of groups B - I in sequence according to the methods of the previous two steps until the excavation of all parts is completed.

Claims

1. A three-dimensional mining test system applicable to gob-side entry retaining with fault structures, characterized in that: It includes a geological model (1), a simulated excavation component (2), a pumping system (3), and a pressurizing system (4); the geological model (1) includes a hanging wall (11) of the fault and a footwall (12) of the fault. The contact surface between the hanging wall (11) and the footwall (12) of the fault is the fault contact surface (13). Both the hanging wall (11) and the footwall (12) of the fault include the strata above the coal seam (14) and the strata below the coal seam (15); several simulated excavation components (2) are provided between the strata above the coal seam (14) and the strata below the coal seam (15). The simulated excavation component (2) includes a liquid storage box (21) with an open top, a conduit (22) for filling the liquid storage box (21) with a dissolving liquid, and a test sample plate (23) for closing the open top of the liquid storage box (21). The dissolving liquid is used to dissolve the test sample plate (23); the pumping system (3) includes a frame (31). A liquid storage tank (32) and a hydraulic cylinder (33) are successively arranged on the frame (31) from bottom to top. The bottom of the liquid storage tank (32) is communicated with the conduit (22) through a connecting pipe (34). The liquid storage tank (32) is used for storing the dissolving liquid. A piston structure (35) is arranged in the liquid storage tank (32). The bottom end of the piston rod of the hydraulic cylinder (33) is inserted into the liquid storage tank (32) and fixedly connected with the piston structure (35); the pressurizing system (4) is used to provide hydraulic oil for the hydraulic cylinder (33) and control the expansion and contraction of the hydraulic cylinder (33).

2. The three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 1, wherein: The dissolving liquid is a polar organic solvent, and the test sample plate (23) is a foam board.

3. A three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 1, characterized in that: The test sample plate (23) is horizontally embedded in the liquid storage box (21).

4. A three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 1, characterized in that: A simulated coal pillar (16) is provided between the strata above the coal seam (14) and the strata below the coal seam (15).

5. A three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 1, characterized in that: A roadway (17) for the connecting pipe (34) to enter is reserved between the strata above the coal seam (14) and the strata below the coal seam (15).

6. The three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 1, wherein: A control valve (36) is provided at the connection between the connecting pipe (34) and the liquid storage tank (32).

7. A three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 6, characterized in that: The connecting pipe (34) is detachably connected to the control valve (36).

8. A three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 7, characterized in that: The control valve (36) is provided with a quick-release joint for connecting with the connecting pipe (34).

9. The three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 1, wherein: The pressurizing system (4) includes a hydraulic servo control system (41) and a hydraulic oil pipe (42) for delivering hydraulic oil to the hydraulic cylinder (33).

10. A three-dimensional mining test system for gob-side entry retaining applicable to fault structures according to claim 1, characterized in that: Hydraulic oil inlets and outlets (37) are provided at both the upper and lower ends of the outer wall of the cylinder body of the hydraulic cylinder (33).

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