Visualization device and method for simulating particle flow under water inrush and sand inrush conditions

Abstract

The invention discloses a visual device and method for simulating particle flow under water inrush and sand inrush conditions, the device comprises a fixing sleeve piece provided with a rock sample, two ends of the fixing sleeve piece are provided with a cylinder shell and a steel column used for applying pressure to the rock sample; a monitoring unit used for observing the flowing condition of a sand body in the rock sample is further arranged in the fixing sleeve, the whole flowing process of sand grains in a crack is observed through the monitoring unit, the whole flowing process comprises the crack opening degree change and the bridging effect caused by blockage of the sand grains in the crack, the whole flowing process is changed into visualization, and the flow condition of the sand grains in the crack is observed through the monitoring unit. And the understanding of the reason for the moment change of the flow in the water guide channel under the conditions of water inrush and sand inrush in coal mining can be enhanced.

Description

Technical Field

[0001] The present invention relates to the field of intelligent production and technical services of mines, and in particular to a visualization device and method for simulating particle flow under conditions of water inrush and sand burst. Background Art

[0002] During coal mining, weakly cemented sandstones are usually found in the overburden above the coal seams. When mining activities cause strata movement and fracture, these sandstones may enter the water-conducting fracture zone. At this time, the structure of weakly cemented sandstone is prone to collapse under the immersion of water, and the cementing material gradually dissolves or is weakened, causing the sand particles to gradually loosen and fall off. Driven by the water flow, these loose sand particles may migrate along the water-conducting fracture zone to form a mud-sand mixture. If the fracture zone channel is unobstructed, these mud and sand will quickly gush out with the water flow, causing a sudden water disaster. The sudden water will not only bring a large amount of water, but also carry sand particles, which will have a huge impact on the working face, which may cause equipment damage, tunnel blockage, and even cause more serious mine disasters. On the contrary, if the fracture zone channel is not smooth, the accumulation of sand particles may gradually block the water flow channel, resulting in increased local water pressure and more complex water damage problems.

[0003] When studying the phenomenon of water and mud bursts, indirect means are usually used on site to observe and analyze this complex process. By laying monitoring wells and installing groundwater level monitoring equipment, researchers can continuously monitor the water level and water pressure changes in the aquifer. These changes can indicate the development of water-conducting fracture zones and the degree of collapse of weakly cemented sandstone. Microseismic monitoring technology provides early warning signals about potential water and mud burst risks by monitoring stratum fractures and rock movement in real time. However, such methods are basically indirect methods, and it is difficult to directly observe the process changes of water and mud bursts and the competitive mechanism of crack blockage. It is necessary to study the process changes of such water disasters from a microscopic perspective. Summary of the invention

[0004] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a visualization device and method for simulating particle flow under conditions of water inrush and sand burst, which can realize the visualization of the entire process of loose particles flowing, migrating and clogging in cracks during coal seam excavation and the theoretical research feasibility it brings.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a visualization device for simulating particle flow under water inrush and sand burst conditions, comprising a hollow fixing kit, a transversely arranged semicircular supporting steel piece is placed in the cavity of the fixing kit, both ends of the supporting steel piece are connected with transversely arranged transparent acrylic plates, a rock sample with a semicircular outer wall is placed on the transparent acrylic plate, and the supporting steel piece and the rock sample form a columnar structure; a receiving steel ring is attached to the left end surface of the columnar structure, and a pressure-bearing steel ring is nested at the right end of the columnar structure; the receiving steel ring is annular and weakly cemented sandstone is placed in its cavity; the left end of the columnar structure is sealed to prevent the sand body of the weakly cemented sandstone from flowing into the internal space of the supporting steel piece after dilution;

[0007] Two cylinder shells are symmetrically threadedly connected at both ends of the fixing kit. The two cylinder shells are hollow and are threadedly connected with steel columns for providing pressure to weakly cemented sandstone and rock samples. The weakly cemented sandstone is sequentially nested with a plurality of rubber rings and a pressure ring steel piece from right to left. The steel column on the left presses the rubber ring onto the end face of the receiving steel ring through the pressure ring steel piece; the right end face of the pressure-bearing steel ring is also provided with a plurality of rubber pads, and the steel column on the right presses the rubber pad onto the pressure-bearing steel ring through an adapted circular sheet;

[0008] A rubber sleeve is embedded in the outer wall of the rock sample, and the two ends of the rubber sleeve are also embedded in the outer periphery of the receiving steel ring and the pressure steel ring. A sealed oil storage cavity is formed between the outer wall of the rubber sleeve, the inner wall of the fixing kit, the pressure ring steel piece, the circular sheet and the two cylinder shells. The upper and lower sides of the fixing kit are respectively provided with an oil inlet and an oil outlet connected to the oil storage cavity;

[0009] A water inlet connected to the weakly cemented sandstone is opened in the middle of the steel column on the left, and a water outlet connected to the rock sample is opened in the middle of the steel column and the pressure-bearing steel ring on the right; a monitoring unit for observing the flow conditions of particles inside the rock sample is also provided in the space formed by the supporting steel parts and the transparent acrylic plate.

[0010] Preferably, the monitoring unit comprises a placement platform with two ends transversely fixed on a supporting steel member, the placement platform is provided with a plurality of vertical slide rails and transverse slide rails, the vertical slide rails and transverse slide rails are respectively slidably connected with a plurality of movable sliders, the sliders are provided with cameras, and the placement platform is also provided with a light source and a power supply. The movement of the sliders is controlled by a motor of the prior art, and no further description is given.

[0011] Preferably, a water-blocking rubber ring is provided between the fixing kit and the cylinder housing.

[0012] Preferably, the water inlet is externally connected to a water body providing device and a corresponding water pressure change detection device to provide monitoring conditions for changes in seepage pressure of crack closure or expansion of rock samples under confining pressure; the water outlet is externally connected to an analytical balance device to monitor changes in water flow and sand particle weight.

[0013] Preferably, both ends of the transparent acrylic plate are bonded to the inner wall of the supporting steel member by epoxy resin.

[0014] Preferably, the oil inlet is externally connected to an oil filling system to fill oil into the oil storage cavity, and the oil outlet is externally connected to an oil storage tank.

[0015] Preferably, the thickness of the pressure ring steel piece is smaller than the total thickness of adjacent rubber rings, so as to prevent leakage of seepage water under the action of external pressure.

[0016] The present invention provides a method for using a visualization device for simulating particle flow under water inrush and sand burst conditions, comprising the following steps:

[0017] S1. Before the experiment, the rock specimens and weakly cemented sandstone on site were sampled and prepared, and placed in the upper part of the transparent acrylic plate and the receiving steel ring respectively;

[0018] S2. Water is introduced through the water inlet. When the water flows to the weakly cemented sandstone, it will soak the weakly cemented sandstone and cause the sandstone to collapse. The sand particles are carried into the cracks by the water and then flow to the outlet through the cracks. Some of the sand particles will be taken out and some will remain in the cracks.

[0019] S3. Inject oil through the oil storage cavity and set the pressure to ensure that the rubber sleeve squeezes the internal rock sample to provide confining pressure;

[0020] S4. The camera and light source on the stage are turned on to monitor the whole process of sand grain flow inside the rock sample;

[0021] S5. The water flowing out of the outlet is received and weighed, and the sand is collected to determine the feedback mechanism between the seepage pressure and the blockage of the cracks by the sand;

[0022] S6. During the entire simulation process, data is collected through water collection at the inlet and outlet and seepage pressure during the seepage process. The frequency of collection relies on the support of field data, and the data performance is explained and supported by the internal visualization process.

[0023] The beneficial effects of the present invention are as follows: the device detects the water inrush and sand burst process through a visualization device of a laboratory test, thereby understanding the flow trend and changes of internal sand particles in the cracks, and the differentiated manifestations of sand particle movement at positions with different roughness and different openings, thereby understanding the changes in water pressure and flow caused by this performance and the changes in the cracks themselves in this process, which can be expressed theoretically and has a promoting effect on the study of water inrush and sand burst in coal seam mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of a visualization device and method for simulating particle flow under water inrush and sand burst conditions provided by an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the structure of a monitoring unit provided in an embodiment of the present invention.

[0027] Description of reference numerals:

[0028] 1. Water inlet; 2. Steel column; 3. Cylinder housing; 4. Rubber ring; 5. Fixing kit; 6. Oil inlet; 7. Camera; 8. Rock sample; 9. Vertical slide rail; 10. Placement table; 11. Rubber sleeve; 12. Horizontal slide rail; 13. Oil outlet; 14. Oil storage cavity; 15. Weakly cemented sandstone; 16. Pressure ring steel; 17. Water-blocking rubber ring; 18. Supporting steel ring; 19. Water outlet; 20. Supporting steel; 21. Power supply; 22. Light source; 23. Acrylic plate; 24. Pressure-bearing steel ring; 25. Round piece; 26. Rubber pad. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 1 to Figure 2 As shown, a visualization device for simulating particle flow under water inrush and sand burst conditions comprises a hollow fixing kit 5, a laterally arranged and semicircular supporting steel piece 20 is placed in the cavity of the fixing kit 5, both ends of the supporting steel piece 20 are connected with laterally arranged transparent acrylic plates 23, a rock sample 8 with a semicircular outer wall is placed on the transparent acrylic plate 23, and the supporting steel piece 20 and the rock sample 8 form a columnar structure; a receiving steel ring 18 is attached to the left end face of the columnar structure, and a pressure-bearing steel ring 24 is nested at the right end of the columnar structure; the receiving steel ring 18 is annular and a weakly cemented sandstone 15 containing through cracks is placed in its cavity; the left end of the columnar structure is sealed to prevent the sand body of the weakly cemented sandstone 15 from flowing into the internal space of the supporting steel piece 20 after dilution; the supporting steel piece 20 can protect the internal devices and instruments from being damaged.

[0031] Two cylinder housings 3 are symmetrically threadedly connected at both ends of the fixing kit 5. The two cylinder housings 3 are hollow and are threadedly connected with steel columns 2 for providing pressure to the weakly cemented sandstone 15 and the rock sample 8. The weakly cemented sandstone 15 is sequentially nested with a plurality of rubber rings 4 and a pressure ring steel part 16 from right to left. The steel column 2 on the left side presses the rubber ring 4 onto the end face of the receiving steel ring 18 through the pressure ring steel part 16; the right end face of the pressure-bearing steel ring 24 is also provided with a plurality of rubber pads 26, and the steel column 2 on the right side presses the rubber pad 26 onto the pressure-bearing steel ring 24 through an adapted circular sheet 25;

[0032] The outer wall of the rock sample 8 is embedded with a rubber sleeve 11, and the two ends of the rubber sleeve 11 are also embedded in the outer periphery of the receiving steel ring 18 and the pressure steel ring 24. A sealed oil storage cavity 14 is formed between the outer wall of the rubber sleeve 11, the inner wall of the fixing kit 5, the pressure ring steel piece 16, the circular sheet 25 and the two cylinder shells 3. The upper and lower sides of the fixing kit 5 are respectively provided with an oil inlet 6 and an oil outlet 13 connected to the oil storage cavity 14;

[0033] A water inlet 1 connected to the weakly cemented sandstone 15 is opened in the middle of the steel column 2 on the left, and a water outlet 19 connected to the rock sample 8 is opened in the middle of the steel column 2 and the pressure-bearing steel ring 24 on the right; a monitoring unit for observing the particle flow condition inside the rock sample 8 is also provided in the space formed by the supporting steel part 20 and the transparent acrylic plate 23.

[0034] The monitoring unit includes a placement platform 10 with both ends transversely fixed on a supporting steel member 20, and the placement platform 10 is provided with a plurality of vertical slide rails 9 and a transverse slide rail 12, and the vertical slide rails 9 and the transverse slide rails 12 are respectively slidably connected with a plurality of movable sliders, and the sliders are provided with a camera 7. The placement platform 10 is also provided with a light source 22 and a power supply 21.

[0035] A water-blocking rubber ring 17 is provided between the fixing kit 5 and the cylinder housing 3. Under the squeezing action, there is a water-blocking effect, and when water is retained from the device here, it will be blocked. At the same time, under the action of water, the water-blocking rubber ring 17 has stronger adsorption and is easier to block water.

[0036] The water inlet 1 is externally connected to a water supply device and a corresponding water pressure change detection device to provide monitoring conditions for the crack closure or expansion seepage pressure changes of the rock sample 8 under the action of confining pressure; the water outlet 19 is externally connected to an analytical balance device to monitor the changes in water flow and sand particle weight.

[0037] Both ends of the transparent acrylic plate 23 are bonded to the inner wall of the supporting steel member 20 by epoxy resin.

[0038] The oil inlet 6 is externally connected to an oil filling system to fill oil into the oil storage cavity 14, and the oil outlet 13 is externally connected to an oil storage tank.

[0039] The thickness of the pressure ring steel member 16 is smaller than the total thickness of the adjacent rubber rings 4, so as to prevent leakage of the seepage water under the action of external pressure.

[0040] The present invention provides a method for using a visualization device for simulating particle flow under water inrush and sand burst conditions, comprising the following steps:

[0041] S1. Before the experiment begins, the rock sample 8 and the weakly cemented sandstone 15 on site are sampled and prepared, and placed on the upper part of the transparent acrylic plate 23 and in the receiving steel ring 18 respectively;

[0042] S2, water is introduced through the water inlet 1. When the water flows to the weakly cemented sandstone 15, it will soak the weakly cemented sandstone 15 and cause the sandstone to collapse. The sand particles are carried into the cracks by the water and then flow to the outlet through the cracks. Some of the sand particles will be taken out and some will remain in the cracks.

[0043] S3, injecting oil and setting the pressure through the oil storage cavity 14, ensuring that the rubber sleeve 11 squeezes the internal rock sample 8 to provide confining pressure;

[0044] S4, the camera 7 and the light source 22 on the placement table 10 are turned on to monitor the whole process of sand grain flow inside the rock sample 8;

[0045] S5, the water flowing out through the water outlet 19 is received and weighed, and the sand is collected to determine the feedback mechanism between the seepage pressure and the blockage of the cracks by the sand;

[0046] S6. During the entire simulation process, data is collected through water collection at the inlet 1 and outlet 19 and the seepage pressure during the seepage process. The frequency of collection relies on the support of field data, and the data performance is explained and supported by evidence through the internal visualization process.

[0047] During the entire simulation process, a visual display of the blockage-flow-bridging-erosion mechanism was achieved, in which the overlying rock strata collapsed under the action of the aquifer and leaked down to the goaf through cracks during coal mining.

[0048] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A visualization device for simulating particle flow under water inrush and sand burst conditions, characterized in that: The invention comprises a hollow fixing kit (5), wherein a transversely arranged and semicircular supporting steel piece (20) is placed in the cavity of the fixing kit (5), and both ends of the supporting steel piece (20) are connected to transversely arranged transparent acrylic plates (23), and a rock sample (8) with a semicircular outer wall is placed on the transparent acrylic plate (23), and the supporting steel piece (20) and the rock sample (8) form a columnar structure; a receiving steel ring (18) is attached to the left end surface of the columnar structure, and a pressure-bearing steel ring (24) is embedded in the right end of the columnar structure; the receiving steel ring (18) is annular and a weakly cemented sandstone (15) is placed in its cavity; the left end of the columnar structure is sealed to prevent the sand body of the weakly cemented sandstone (15) from flowing into the internal space of the supporting steel piece (20) after dilution; Two cylinder housings (3) are symmetrically threadedly connected at both ends of the fixing kit (5). The two cylinder housings (3) are hollow and are threadedly connected with steel columns (2) for providing pressure to the weakly cemented sandstone (15) and the rock sample (8). The weakly cemented sandstone (15) is sequentially embedded with a plurality of rubber rings (4) and a pressure ring steel component (16) from right to left. The steel column (2) on the left side presses the rubber ring (4) onto the end face of the receiving steel ring (18) through the pressure ring steel component (16); the right end face of the pressure-bearing steel ring (24) is also provided with a plurality of rubber pads (26), and the steel column (2) on the right side presses the rubber pad (26) onto the pressure-bearing steel ring (24) through an adapted circular sheet (25); A rubber sleeve (11) is embedded in the outer wall of the rock sample (8), and the two ends of the rubber sleeve (11) are also embedded in the outer periphery of the receiving steel ring (18) and the pressure-bearing steel ring (24). A sealed oil storage cavity (14) is formed between the outer wall of the rubber sleeve (11), the inner wall of the fixing kit (5), the pressure ring steel piece (16), the circular sheet (25) and the two cylinder shells (3). The upper and lower sides of the fixing kit (5) are respectively provided with an oil inlet (6) and an oil outlet (13) connected to the oil storage cavity (14); A water inlet (1) connected to the weakly cemented sandstone (15) is provided in the middle of the steel column (2) on the left, and a water outlet (19) connected to the rock sample (8) is provided in the middle of the steel column (2) and the pressure-bearing steel ring (24) on the right; a monitoring unit for observing the flow of particles inside the rock sample (8) is also provided in the space formed between the supporting steel member (20) and the transparent acrylic plate (23).

2. A visualization device and method for simulating particle flow under water inrush and sand burst conditions as claimed in claim 1, characterized in that: The monitoring unit comprises a placement platform (10) with both ends transversely fixed on a supporting steel member (20), the placement platform (10) being provided with a plurality of vertical slide rails (9) and transverse slide rails (12), the vertical slide rails (9) and transverse slide rails (12) being respectively slidably connected with a plurality of movable sliders, the sliders being provided with cameras (7), and the placement platform (10) being also provided with a light source (22) and a power source (21).

3. A visualization device for simulating particle flow under water inrush and sand burst conditions as claimed in claim 1, characterized in that: A water-blocking rubber ring (17) is provided between the fixing kit (5) and the cylinder housing (3).

4. A visualization device for simulating particle flow under water inrush and sand burst conditions as claimed in claim 1, characterized in that: The water inlet (1) is externally connected to a water supply device and a corresponding water pressure change detection device to provide monitoring conditions for changes in seepage pressure of crack closure or expansion of the rock sample (8) under the action of confining pressure; the water outlet (19) is externally connected to an analytical balance device to monitor changes in water flow and sand particle weight.

5. A visualization device for simulating particle flow under water inrush and sand burst conditions as claimed in claim 1, characterized in that: The two ends of the transparent acrylic plate (23) are bonded to the inner wall of the supporting steel member (20) by epoxy resin.

6. A visualization device for simulating particle flow under water inrush and sand burst conditions as claimed in claim 1, characterized in that: The oil inlet (6) is externally connected to an oil filling system for filling oil into the oil storage cavity (14), and the oil outlet (13) is externally connected to an oil storage tank.

7. A visualization device for simulating particle flow under water inrush and sand burst conditions as claimed in claim 1, characterized in that: The thickness of the pressure ring steel member (16) is smaller than the total thickness of the adjacent rubber rings (4), thereby preventing leakage of seepage water under the action of external pressure.

8. A method for using the visualization device for simulating particle flow under water inrush and sand burst conditions as claimed in claim 1, characterized in that: The following steps are involved: S1. Before the experiment begins, the rock samples (8) and weakly cemented sandstone (15) on site are sampled and prepared, and placed on the upper part of the transparent acrylic plate (23) and in the receiving steel ring (18) respectively; S2. Water is introduced through the water inlet (1). When the water flows to the weakly cemented sandstone (15), the weakly cemented sandstone (15) is soaked, causing the sandstone to collapse. Sand particles are carried into the cracks by the water and then flow to the outlet through the cracks. Some of the sand particles are carried out, while some remain in the cracks. S3, injecting oil and setting pressure through the oil storage cavity (14), ensuring that the rubber sleeve (11) squeezes the internal rock sample (8) to provide confining pressure; S4, the camera (7) and the light source (22) on the placement table (10) are turned on to monitor and record the entire process of sand grain flow inside the rock sample (8); S5, the water flowing out through the water outlet (19) is received and weighed, and the sand is collected to determine the feedback mechanism between the seepage pressure and the blockage of the cracks by the sand; S6. During the entire simulation process, data is collected through water collection at the water inlet (1) and the water outlet (19) and the seepage pressure during the seepage process. The frequency of data collection relies on the support of field data, and the data performance is explained and supported by evidence through the internal visualization process.

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