Rock dynamic mechanical property experimental device and method

Abstract

The invention discloses a rock dynamic mechanical property experiment device and method, and relates to the technical field of coal seam overlying rock mechanical detection.The rock dynamic mechanical property experiment device comprises a monitoring device used for providing a sample dynamic image; the transmission device is electrically connected with the monitoring device; the loading assembly is fixed on the workbench and is used for loading the sample; the loading assembly comprises a support, a control box is fixed to the upper end of the support, a control panel is installed on the control box, a pressure applying cylinder is fixed to the middle of the interior of the control box, at least two adjusting motors are symmetrically distributed in the control box, a bottom plate is fixed to the support, and the bottom plate is fixed to the control box. A plurality of stand columns are symmetrically arranged between the bottom plate and the control box, the sample is placed on the bottom plate, and a pressure applying assembly is arranged on the stand columns in a sliding mode and driven by a pressure applying cylinder.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical detection of overlying rocks on coal seams, and in particular to a rock dynamic mechanical property experimental device and method. Background Art

[0002] At present, coal is still the most important and reliable form of energy in my country. However, while coal mining plays a huge role in the development of the national economy, it also inevitably causes damage to the ecological environment of the mining area, such as soil and vegetation destruction and landscape changes, large-scale land subsidence and surface cracks, groundwater level decline and water resource loss, and coal gangue mountains occupying land and polluting the environment.

[0003] The existing rock dynamic mechanical properties experimental device measures the rock dynamic mechanical properties by directly applying pressure to the rock and gradually increasing the pressure. It has great limitations and cannot simulate the dynamic changes of the overlying rock of the coal seam affected by the mining speed and length during coal seam mining, and thus cannot determine the safe range of mining.

[0004] In view of the above problems, the present invention provides a rock dynamic mechanical properties experimental device and method to solve the above problems. Summary of the invention

[0005] To achieve the above object, the present invention provides the following technical solution: a rock dynamic mechanical properties experimental device and method, comprising:

[0006] A monitoring device for providing dynamic images of the sample;

[0007] a transmission device, electrically connected to the monitoring device;

[0008] A loading assembly, fixed on the workbench, used to load the specimen;

[0009] Wherein, the loading assembly includes a bracket, a control box is fixed on the upper end of the bracket, a control panel is installed on the control box, a pressure cylinder is fixed at the middle position inside the control box, at least two adjustment motors are symmetrically arranged inside the control box, a base plate is fixed on the bracket, a plurality of columns are symmetrically arranged between the base plate and the control box, the sample is placed on the base plate, a plurality of pressure assemblies are slidably arranged on the columns, and the pressure assembly is driven by the pressure cylinder.

[0010] Further, preferably, the transmission device is a digital imager or a distributed fiber optic sensor, wherein, when the transmission device is a digital imager, the device also includes a lighting device for illuminating the sample, and the model of the distributed fiber optic sensor is an OSI-S OFDR distributed fiber optic sensor.

[0011] Further, preferably, the pressure applying component comprises:

[0012] A sliding plate, slidably disposed on the column;

[0013] A coupling, one end of which is fixed to the sliding plate, and the other end of which is fixed to the pressure cylinder;

[0014] The adjusting columns are configured as a plurality of columns and are arranged equidistantly on the sliding plate;

[0015] The pressure plates are configured as two and fixed to the lower end surfaces of the plurality of adjusting columns, and the adjusting columns are sleeved with pressure springs between the sliding plate and the pressure plate, and the number of the adjusting columns on the two pressure plates is the same;

[0016] The adjusting plates are configured in two, are slidably connected to the plurality of adjusting columns, and correspond one-to-one to the two pressure plates;

[0017] The adjusting components are configured in two, both of which are rotatably arranged on the sliding plate and correspond one-to-one to the two adjusting plates.

[0018] Further, preferably, the adjusting column comprises a sliding column, and a limiting disk is fixed on the upper end surface of the sliding column.

[0019] Further, preferably, the adjustment component comprises:

[0020] The threaded rods are configured as four and are symmetrically and rotationally arranged on the sliding plate, and the threaded rods are threadedly connected to the adjusting plate;

[0021] The synchronous gears are configured in four pieces and are respectively fixed on the upper end surfaces of the four threaded rods;

[0022] The synchronous belt is configured into four and is connected with the four synchronous gears in sequence.

[0023] Further, preferably, a limit slot is provided on the upper end surface of the synchronous gear, and the adjustment motor fixed in the control box corresponds to one of the limit slots.

[0024] An experimental method for a rock dynamic mechanical properties experimental device comprises the following steps:

[0025] S1. Preparation of samples: using sieved river sand as the main aggregate and lime and gypsum powder as the binder;

[0026] S2. Determine the observation plan of the sample; use a digital imager or a distributed optical fiber sensor for observation;

[0027] S3. Loading the sample; placing the sample on the bottom plate, and then determining the observation point on the sample;

[0028] S4. Determine the position of the working surface of the sample; measure the thickness of the overburden on the working surface;

[0029] S5. Apply pressure to the sample; apply different pressures through overburden of different thicknesses to make the bulk density similarity ratio between the sample and the actual situation 1.5:1;

[0030] S6. Mining of the working face; each excavation is 5 cm, representing an actual mining speed of 7.5 m / d, in order to study the dynamic movement and deformation of rock and soil layers under conditions of rapid advancement on a small time scale.

[0031] Compared with the prior art, the present invention provides a rock dynamic mechanical properties experimental device and method, which has the following beneficial effects:

[0032] In the present invention, the total pressure of the overburden on the working surface can be simulated by the pressure-applying component, thereby reducing the material usage when making samples, and can provide pressure according to the positions of different working surfaces, thereby simulating the situation when the working surface is located at different positions, which is more convenient for studying the dynamic mechanical properties of rocks, and when it is only necessary to test the overburden of a working surface at one position, the two adjusting components are adjusted to the same pressure, thereby applying pressure to the sample as a whole. At this time, the working surface is mined from left to right, and the observation point is located in front of the sample. When it is necessary to test the overburden of two working surfaces at two different positions, the two adjusting components are adjusted to different pressures, thereby applying pressure to both sides of the sample respectively. At this time, the working surface is mined from front to back, and the observation points are located on the two side walls of the sample, which is convenient for simulating experiments on working surfaces under different conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of a rock dynamic mechanical properties experimental device;

[0034] Figure 2 It is a schematic diagram of the loading component structure of a rock dynamic mechanical properties experimental device;

[0035] Figure 3 A schematic diagram of the structure of a pressure component of a rock dynamic mechanical properties experimental device;

[0036] Figure 4 It is a schematic diagram of the local structure of a pressure component of a rock dynamic mechanical properties experimental device;

[0037] Figure 5 It is a schematic diagram of the first state of the working face of a rock dynamic mechanical properties experimental device;

[0038] Figure 6 It is a schematic diagram of the second state of the working face of a rock dynamic mechanical properties experimental device;

[0039] Figure 7This is a schematic diagram of the overburden damage state on the working face;

[0040] Figure 8 This is a schematic diagram of the changes in the fracture angle of the overlying rock strata on the working face;

[0041] Fig. 9 This is a schematic diagram of the change of the fracture angle of the rock formation on the side of the cut eye;

[0042] Fig.10 This is a schematic diagram of the change of the rock fracture angle at the lower right side of the working face;

[0043] In the figure: 1. monitoring device; 2. transmission device; 3. lighting device; 4. sample; 41. working surface; 42 observation point; 5. bracket; 6. control box; 7. control panel; 8. bottom plate; 9. pressure assembly; 10. column; 91. sliding plate; 92. coupling; 93. adjusting column; 94. pressure spring; 95. pressure plate; 96. adjusting plate; 97. adjusting assembly; 931. sliding column; 932. limit plate; 971. threaded rod; 972. synchronous gear; 973. limit groove; 974. synchronous belt. DETAILED DESCRIPTION

[0044] Reference Figure 1-Figure 6 The present invention provides a technical solution: a rock dynamic mechanical properties experimental device and method, comprising:

[0045] A monitoring device 1, for providing a dynamic image of a sample 4;

[0046] A transmission device 2, electrically connected to the monitoring device 1;

[0047] A loading assembly, fixed on the workbench, used to load the sample 4;

[0048] Among them, the loading assembly includes a bracket 5, a control box 6 is fixed on the upper end of the bracket 5, a control panel 7 is installed on the control box 6, a pressure cylinder is fixed at the middle position inside the control box 6, at least two adjustment motors are symmetrically arranged inside the control box 6, a base plate 8 is fixed on the bracket 5, a plurality of columns 10 are symmetrically arranged between the base plate 8 and the control box 6, the sample 4 is placed on the base plate 8, and a pressure assembly 9 is slidably arranged on the plurality of columns 10, and the pressure assembly 9 is driven by the pressure cylinder.

[0049] In this embodiment, the transmission device 2 is a digital imager or a distributed fiber optic sensor. When the transmission device 2 is a digital imager, the device also includes an illumination device 3 for illuminating the sample 4. The model of the distributed fiber optic sensor is an OSI-S OFDR distributed fiber optic sensor.

[0050] It should be noted that the transmission device 2 used in this embodiment is a distributed optical fiber sensor.

[0051] In this embodiment, the pressure applying component 9 includes:

[0052] A sliding plate 91, slidably disposed on the column 10;

[0053] A coupling 92, one end of which is fixed to the sliding plate 91, and the other end of which is fixed to the pressure cylinder;

[0054] The adjusting columns 93 are configured as a plurality and are equidistantly arranged on the sliding plate 91;

[0055] The pressure plates 95 are configured as two and fixed to the lower end surfaces of the plurality of adjustment columns 93, and the adjustment columns 93 are sleeved with pressure springs 94 between the sliding plate 91 and the pressure plates 95, and the number of the adjustment columns 93 on the two pressure plates 95 is the same;

[0056] The adjusting plates 96 are configured in two, are slidably connected to the plurality of adjusting columns 93, and correspond one-to-one to the two pressure plates 95;

[0057] The adjusting components 97 are configured as two, both of which are rotatably disposed on the sliding plate 91 and correspond one-to-one to the two adjusting plates 96 .

[0058] That is to say, the pressure component 9 can simulate the total pressure of the overlying rock on the working surface 41, thereby reducing the material usage when making the sample 4, and can provide pressure according to the position of different working surfaces 41, thereby simulating the situation when the working surface 41 is located at different positions, which is more convenient for studying the dynamic mechanical properties of rocks.

[0059] Among them, when the working surface 41 is in the first state, as Figure 5 When only one overburden rock of the working face 41 at one position needs to be tested, the two adjustment components 97 are adjusted to the same pressure, so that the sample 4 is pressed as a whole. At this time, the working face 41 is mined from left to right, and the observation point 42 is located in front of the sample;

[0060] When the working surface 41 is in the second state, Figure 6 When it is necessary to test the overlying rock of the working faces 41 at two different positions, the two adjusting components 97 are adjusted to different pressures, so as to apply pressure to the two sides of the sample 4 respectively. At this time, the working face 41 is mined from the front to the back, and the observation points 42 are located on the two side walls of the sample 41, which is convenient for simulating experiments on the working face 41 under different conditions.

[0061] As a preferred embodiment, the adjusting column 93 includes a sliding column 931 , and a limiting plate 932 is fixed to the upper end surface of the sliding column 931 .

[0062] As a preferred embodiment, the adjustment component 97 includes:

[0063] The threaded rods 971 are configured as four and are symmetrically and rotationally arranged on the sliding plate 91 , and the threaded rods 971 are threadedly connected to the adjusting plate 96 ;

[0064] The synchronous gears 972 are configured in four numbers and are respectively fixed on the upper end surfaces of the four threaded rods 971;

[0065] The synchronous belts 974 are configured in four numbers and are connected to the four synchronous gears 972 in sequence.

[0066] As a preferred embodiment, a limiting groove 973 is provided on the upper end surface of the synchronous gear 972 , and the regulating motor fixed in the control box 6 corresponds to one of the limiting grooves 973 .

[0067] It should be noted that when adjusting the adjustment component 97, the pressure component 9 is first moved upward through the pressure cylinder, so that the limit groove 973 of the synchronous gear 972 is connected to the output end of the adjustment motor. At this time, the adjustment motor rotates, so that the multiple threaded rods 971 rotate synchronously, so that the adjustment plate 96 can rise or fall horizontally, thereby adjusting the position of the pressure plate 95 to avoid uneven pressure.

[0068] An experimental method for a rock dynamic mechanical properties experimental device comprises the following steps:

[0069] S1. Preparation of sample 4; using sieved river sand as the main aggregate, and lime and gypsum powder as the binder;

[0070] S2. Determine the observation plan of sample 4; use a digital imager or a distributed fiber optic sensor for observation;

[0071] S3. Loading the sample 4; placing the sample 4 on the base plate 8, and then determining the observation point 42 on the sample 4;

[0072] S4. Determine the position of the two working surfaces 41 of the sample 4; measure the thickness of the overburden on the working surface 41;

[0073] S5. Apply pressure to sample 4; apply different pressures through overburden of different thicknesses so that the bulk density similarity ratio of sample 4 to the actual situation is 1.5:1;

[0074] S6. Mining of working face 41; each excavation is 5 cm, representing an actual mining speed of 7.5 m / d, in order to study the dynamic movement and deformation of rock and soil layers under conditions of rapid advancement on a small time scale.

[0075] like Figure 7-10,It should be noted that this experiment simulates the mining ,situation of the super-large working face in the Shendong mining area, where the ,mining speed is fast and is generally above 5m / d;

[0076] When the advance reached 45 cm (i.e., the cumulative advance was 67.5 m), the overlying rock suddenly collapsed on a large scale ( Figure 7 ), the maximum height of the detachment is about 36m, the maximum width of the top detachment is about 30m, the length of the uppermost part of the detachment is about 8m, and the length of the middle part of the detachment is about 49m. An obvious two-layer hinged structure is formed at the left end, while the lower rock layer on the right is fractured, and a weaker hinged structure is formed at the upper part. Overall, the lower part of the collapsed rock mass remains relatively intact, and it is preliminarily determined that the initial pressure step distance of the old top is 67m. According to observations, the breaking angle on the left side is about 60°, and the breaking angle on the right side is about 50°. The breaking angle on the opening side is larger than that on the working face side. The spatial structure of the bedrock block where the bedrock is initially broken is asymmetric, and the maximum detachment zone is located in the middle of the broken rock beam, biased towards the opening side.

[0077] like Fig. 9 When the working face advances to 194m, the rock formation breaking angle changes at the hard rock layer, and the rock formation breaking angle increases by about 20%. At this time, the rock formation breaking fracture is closer to the vertical angle, and the rock formation failure morphology on the cut side becomes steeper. As the working face continues to advance forward, the rock formation breaking angle continues to increase above the hard rock layer and continues to develop upward until the mining impact is transmitted to the loose layer. After the mining impact is transmitted to the surface through the breaking and movement of the rock and soil layer, as the working face continues to advance forward, the mining impact gradually moves away from the rock formation breaking area on the cut side, making the rock formation breaking on this side less affected, and the rock formation breaking angle basically no longer changes. When the working face stops mining, it basically maintains its original shape. This shows that the hard rock layer has a greater impact on the size of the rock formation breaking angle on the cut side and has a direct impact on the development direction of the rock formation breaking angle.

[0078] like Fig.10 Through the observation and analysis of the rock fracture angle on the side of the working face during the physical simulation experiment, it was found that the rock fracture angle on the side of the working face is not only affected by geological conditions, but also by multiple factors such as the advancing speed of the working face and continuous disturbance of mining. Therefore, the development characteristics of the rock fracture angle on the side of the working face are relatively complex.

[0079] Depend on Fig. 9 and Fig.10By comparison, it can be seen that the fracture angle variation characteristics of the top plate of the working face are relatively complex, and there are obvious jumps at different advancement distances of the working face. The analysis shows that the fracture angle of the rock formation on the working face side is affected by the continuous disturbance of mining activities and the degree of mining sufficiency. The degree of variation of the fracture angle of the rock formation is high in the inadequate mining stage, which is due to the insufficient fall of the rock formation after fracture. When entering the sufficient mining stage, the change of the fracture angle of the rock formation is due to the sliding instability of the cantilever beam structure on the working face side.

[0080] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A rock dynamic mechanical properties experimental device, characterized by: include: A monitoring device (1) for providing a dynamic image of a sample (4); A transmission device (2) electrically connected to the monitoring device (1); A loading assembly, fixed on the workbench, used to load the sample (4); The loading assembly comprises a bracket (5), a control box (6) is fixed on the upper end of the bracket (5), a control panel (7) is installed on the control box (6), a pressure cylinder is fixed at the middle position inside the control box (6), at least two adjustment motors are symmetrically arranged inside the control box (6), a base plate (8) is fixed on the bracket (5), a plurality of columns (10) are symmetrically arranged between the base plate (8) and the control box (6), the sample (4) is placed on the base plate (8), a plurality of columns (10) are slidably arranged with pressure assemblies (9), and the pressure assemblies (9) are driven by the pressure cylinder.

2. A rock dynamic mechanical properties experimental device according to claim 1, characterized in that: The transmission device (2) is a digital imager or a distributed optical fiber sensor. When the transmission device (2) is a digital imager, the device further comprises an illumination device (3) for illuminating the sample (4). The model of the distributed optical fiber sensor is an OSI-S OFDR distributed optical fiber sensor.

3. A rock dynamic mechanical properties experimental device according to claim 1, characterized in that: The pressure applying component (9) comprises: A sliding plate (91) slidably disposed on the column (10); A coupling (92), one end of which is fixed on the sliding plate (91) and the other end of which is fixed on the pressure cylinder; The adjusting columns (93) are configured as a plurality of columns and are equidistantly arranged on the sliding plate (91); The pressure plates (95) are configured as two and fixed to the lower end surfaces of the plurality of adjustment columns (93), and the adjustment columns (93) are sleeved with pressure springs (94) located between the sliding plate (91) and the pressure plates (95), and the number of the adjustment columns (93) on the two pressure plates (95) is the same; The adjustment plates (96) are configured in two, are slidably connected to the plurality of adjustment columns (93), and correspond one-to-one to the two pressure plates (95); The adjustment components (97) are configured in two, both of which are rotatably arranged on the sliding plate (91) and correspond one-to-one to the two adjustment plates (96).

4. A rock dynamic mechanical properties experimental device according to claim 3, characterized in that: The adjusting column (93) comprises a sliding column (931), and a limiting plate (932) is fixed on the upper end surface of the sliding column (931).

5. A rock dynamic mechanical properties experimental device according to claim 3, characterized in that: The adjustment component (97) comprises: The threaded rods (971) are configured as four and are symmetrically and rotationally arranged on the sliding plate (91), and the threaded rods (971) are threadedly connected to the adjustment plate (96); The synchronous gears (972) are configured in four pieces and are respectively fixed on the upper end surfaces of the four threaded rods (971); The synchronous belts (974) are configured in four numbers and are connected to the four synchronous gears (972) in sequence.

6. A rock dynamic mechanical properties experimental device according to claim 5, characterized in that: The upper end surface of the synchronous gear (972) is provided with a limiting groove (973), and the regulating motor fixed in the control box (6) corresponds to one of the limiting grooves (973).

7. The experimental method of the rock dynamic mechanical properties experimental device according to claim 6 is characterized by: The steps include: S1. Preparation of sample (4); using sieved river sand as the main aggregate and lime and gypsum powder as the binder; S2. Determine the observation plan of the sample (4); observe using a digital imager or a distributed fiber optic sensor; S3. Loading the sample (4); placing the sample (4) on the base plate (8), and then determining the observation point (42) on the sample (4); S4. Determine the position of the working surface (41) of the sample (4); measure the thickness of the overburden on the working surface (41); S5. Applying pressure to the sample (4); applying different pressures to the overburden of different thicknesses, so that the bulk density similarity ratio of the sample (4) to the actual situation is 1.5:1; S6. Mining of the working face (41); excavation of 5 cm each time represents an actual mining speed of 7.5 m / d, in order to study the dynamic movement and deformation of rock and soil layers under conditions of rapid advancement on a small time scale.

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