CN109958420A - Visualized test device and test method for simulating the evolution of cracks in coal mining roadway - Google Patents

Abstract

Simulate the visual test device that stope of coal mines tunnel crack develops, including vacuum barrel, transparent mould molding box and particle are evenly distributed with case, vacuum barrel includes upper cover and staving, pressure tester and pump-line are installed on upper lid, the upper end of pump-line is connected with vacuum pump, transparent mould molding box is mounted on bottom centre in staving, particle is evenly distributed with the surface that case is located at transparent mould molding box, the upside of transparent mould molding box is open, the leading flank of transparent mould molding box offers round drainage hole, rectangle water pocket is equipped in transparent mould molding box, rectangle water pocket is connected with drainpipe, the water outlet of drainpipe passes through round drainage hole, the water outlet of drainpipe is equipped with drain valve, the upper side and lower side that particle is evenly distributed with case is open, particle, which is evenly distributed on the downside of case, is fixedly connected with particle dispensing board group, the front and rear sides that particle launches board group are respectively fixedly connected in the front and rear sides of staving On wall.The present invention has the advantages that design science, model that is structurally reasonable, facilitating production stope of coal mines roadway surrounding rock structure.

Description

Visualized test device and test method for simulating the evolution of cracks in coal mining roadway

technical field

The invention relates to the field of coal mine simulation experiment devices, in particular to a visual experiment device for simulating the evolution of fissures in coal mining roadways and a testing method thereof.

Background technique

The surrounding rock of coal mining roadway is a composite structure composed of roof, floor and two gangs of different lithologies. The mechanical properties such as strength and stress characteristics of each part of the roadway surrounding rock composite structure are different. Only by mastering the crack evolution law of the coal-rock composite structure can effective support be adopted to realize the precise control of the roadway surrounding rock stability.

Due to the complexity of the underground engineering environment and the difficulty of on-site research, the similar simulation test has become an important scientific research method to realize the reproduction of such complex engineering environments such as geotechnical, geological and mines. However, the existing similar simulation tests can only observe the surface deformation and cracks of the model, and it is difficult to conduct in-depth analysis and research on the entire deformation and crack propagation of the surrounding rock of the roadway.

In order to solve the above problems, people have been looking for an ideal technical solution.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a visual test device and a test method for simulating the evolution of cracks in coal mining roadways, which is scientific in design, reasonable in structure, and convenient for making models of surrounding rock structures of coal mining roadways.

To achieve the above object, the present invention adopts the following technical solutions:

A visual test device for simulating the evolution of cracks in coal mining tunnels, including a vacuum barrel, a transparent model box and a particle uniform distribution box. The vacuum barrel includes an upper cover and a barrel body. The lower end extends into the interior of the vacuum barrel, and the upper end of the suction pipe is connected with a vacuum pump. The upper cover, barrel body, transparent model box and particle distribution box are all made of transparent materials. The shapes of the transparent model box and particle distribution box are all The hollow cuboid structure, the transparent model box is fixedly installed in the bottom center of the barrel body, the particle distribution box is installed in the upper part of the barrel body and is located directly above the transparent model box, the upper side of the transparent model box is open, and the middle of the front side of the transparent model box is opened. There are circular drainage holes. The transparent model box is provided with a rectangular water bag arranged in the horizontal direction of the front and rear. The rectangular water bag is connected with a drainage pipe. The water outlet of the drainage pipe is located outside the transparent model box through the circular drainage hole. The water outlet end of the pipe is provided with a drain valve, the upper and lower sides of the particle uniform distribution box are open, and the particle distribution box is fixedly connected to the particle delivery plate group on the lower side. The front and rear sides are respectively fixedly connected to the inner walls of the front and rear sides of the barrel body.

The particle feeding plate group includes an upper plate and a lower plate. The upper plate and the lower plate are rectangular plates arranged horizontally. The size of the upper plate and the lower plate are the same. The cross section of the particle uniform distribution box is smaller than the upper plate, and the lower The side is fixedly connected to the upper surface of the upper plate, the upper plate is corresponding to the lower plate up and down, the lower plate is slidably arranged on the barrel body below the upper plate, and the front and rear sides of the upper plate are fixedly connected to the barrel body through two horizontal connecting shafts respectively. On the inner walls of the front and rear sides of the barrel, the front and rear sides of the lower plate are slidably connected to the inner walls of the barrel body on the front and rear sides through two horizontal sliding shafts, and the front ends of the two horizontal sliding shafts on the front side protrude from the front side of the barrel body. The rear ends of the two horizontal sliding shafts on the rear side protrude from the rear side of the barrel body. The upper plate is evenly provided with a number of upper throwing through holes, and the lower plate is evenly opened with a number of lower throwing through holes. When aligning, each upper throwing hole and each lower throwing hole are staggered with each other, and when the lower plate slides forward and the upper plate is staggered, each upper throwing hole corresponds to each lower throwing hole one by one.

Both the upper throwing through hole and the lower throwing through hole are rectangular holes.

The drain pipe and the circular drain hole are sealed and connected, and an air valve is arranged on the air extraction pipe.

A test method for a visual test device for simulating the evolution of cracks in a coal mine mining roadway includes the following steps:

(1) Configure the simulated base plate in the transparent model box;

(2) Configure the simulated coal seam on the top of the simulated bottom plate in the transparent model box;

(3) A simulated roof at the top of the simulated coal seam is arranged in the transparent model box;

(4) Take out the transparent model box from the vacuum barrel;

(5) Apply pressure to the simulated bottom plate, simulated coal seam and simulated roof prepared in the transparent model box, and observe the evolution process of the simulated coal mine tunnel cracks.

Step (1) is as follows: place the transparent model box in the center of the bottom of the vacuum barrel, then add the calculated volume of pore liquid into the transparent model box, install the upper plate and the lower plate, and then install the particle uniform distribution box on the On the upper surface of the upper plate, put quantitative transparent soil particles into the particle uniform distribution box, then cover the upper cover on the barrel to isolate the vacuum barrel from the outside world, start the vacuum pump, and when the pressure tester detects the vacuum inside the vacuum barrel When the temperature reaches the specified value, the vacuum pump stops working, and the two horizontal sliding shafts on the front side are twitched, so that the lower plate slides forward for a certain distance, the upper plate and the lower plate are staggered, and each upper feeding through hole is one by one with each lower feeding through hole. The upper and lower sides correspond to each other, so that the transparent soil particles are uniformly scattered into the pore liquid in the transparent model box through the upper and lower injection through holes from the particle uniform distribution box, and the transparent soil particles and the pore liquid penetrate and merge with each other to form a simulated bottom plate.

Step (2) is as follows: push the two horizontal sliding shafts on the front side to make the lower plate slide back and reset, the upper plate and the lower plate are aligned up and down, each upper throwing through hole and every lower throwing through hole are staggered from each other, and the upper plate is opened. cover, take out the particle distribution box from the barrel, and then place the rectangular water bag in the middle of the upper surface of the bottom plate along the front and rear directions. The end is set on the outside of the transparent model box, and the calculated volume of pore liquid is added to the transparent model box. After that, the particle distribution box is installed on the upper surface of the upper plate, and the quantitative transparent soil particles are put into the particle distribution box. , then cover the upper cover on the barrel to isolate the vacuum barrel from the outside world, and start the vacuum pump. When the vacuum degree in the vacuum barrel detected by the pressure tester reaches the specified value, the vacuum pump stops working and twitches the two horizontal sliding shafts on the front side. , make the lower plate slide forward for a certain distance, the upper plate and the lower plate are staggered, and each upper throwing hole corresponds to each lower throwing hole one by one, so that the transparent soil particles can evenly pass through the upper throwing hole from the particle uniform distribution box. The holes and the through holes are scattered into the pore liquid in the transparent model box, and the transparent soil particles and the pore liquid penetrate and merge with each other to form a simulated coal seam.

Step (3) is as follows: push the two horizontal sliding shafts on the front side to make the lower plate slide back and reset, the upper plate and the lower plate are aligned up and down, each upper throwing hole and each lower throwing hole are staggered from each other, and the upper plate is opened. Cover, take out the particle uniform distribution box from the barrel, add the calculated volume of pore liquid into the transparent model box, then install the particle uniform distribution box on the upper surface of the upper plate, and put quantitative transparent soil particles into the particle uniform distribution box. In the cloth box, then cover the top cover on the barrel to isolate the vacuum barrel from the outside world, and start the vacuum pump. When the vacuum degree in the vacuum barrel detected by the pressure tester reaches the specified value, the vacuum pump stops working and twitches the front two. The horizontal sliding shaft makes the lower plate slide forward for a certain distance, the upper plate and the lower plate are staggered, and each upper feeding through hole corresponds to each lower feeding through hole one by one, so that the transparent soil particles can pass through the particle uniform distribution box evenly. The upper feeding through holes and the lower feeding through holes are scattered into the pore liquid on the upper side of the simulated coal seam in the transparent model box, and the transparent soil particles and the pore liquid penetrate and merge with each other to form a simulated roof.

Step (4) is specifically as follows: push the two horizontal sliding shafts on the front side to make the lower plate slide back and reset, the upper plate and the lower plate are aligned up and down, each upper and lower throwing holes are staggered, and the upper Cover, take out the particle uniform distribution box from the barrel, disassemble the upper and lower plates, then take out the transparent model box, and add a rectangular pressure plate on the upper side of the transparent model box.

Step (5) is specifically as follows: placing the transparent model box on the mechanical testing machine, then discharging the water in the rectangular water bag through the drain pipe, starting the mechanical testing machine, and applying pressure to the transparent model box to simulate the excavation of the coal mine roadway, through the The transparent model box is used to observe the simulated coal mine mining roadway crack evolution.

Compared with the prior art, the present invention has outstanding substantive features and significant progress. Specifically, the transparent model box of the present invention is placed in the center of the bottom of the barrel of the vacuum barrel, and the particle uniform distribution box is set directly above the transparent model box. The invention sequentially adds a certain volume of pore liquid and quantitative transparent soil particles into the transparent model box to make the models of the bottom plate, the top plate and the coal seam, and simulates the mining roadway of the coal mine through the rectangular water bag, so as to make the surrounding rock structure of the mining roadway of the coal mine. model in order to simulate the evolution of cracks in coal mining roadways.

The synthetic transparent soil particles have similar physical and mechanical properties to the real soil, and have good transparency. Using the transparent soil experimental material to simulate the deformation and failure of the coal mine mining roadway will help us to fully grasp the crack evolution law of the coal-rock composite structure, and provide a reliable scientific basis for optimizing the roadway design and construction plan.

The visual test device and the test method for simulating the evolution of the fissures of the coal mining roadway of the present invention have the advantages of scientific design, reasonable structure and convenient production of the model of the surrounding rock structure of the coal mining roadway.

Description of drawings

Figure 1 is a front view of the present invention.

Figure 2 is a left side view of the present invention.

FIG. 3 is a schematic diagram of the structure of the upper plate of the present invention.

FIG. 4 is a schematic diagram of the structure of the lower plate of the present invention.

In the picture: 1. Transparent model box; 2. Particle uniform distribution box; 3. Top cover; 4. Barrel body; 5. Pressure tester; 6. Air suction pipe; 7. Circular drainage hole; ; 9. Drain pipe; 10. Drain valve; 11. Upper plate; 12. Lower plate; 13. Horizontal connecting shaft; 14. Horizontal sliding shaft; 15. Upper feeding through hole; 16. Lower feeding through hole; 17. Air valve.

Detailed ways

Embodiments of the present invention are further described below with reference to the accompanying drawings.

As shown in Figures 1-4, the visual test device for simulating the evolution of cracks in coal mining tunnels includes a vacuum barrel, a transparent model box 1 and a particle uniform distribution box 2. The vacuum barrel includes an upper cover 3 and a barrel body 4. The upper cover 3 is on A pressure tester 5 and a suction pipe 6 are installed, the lower end of the suction pipe 6 extends into the barrel 4, the upper end of the suction pipe 6 is connected with a vacuum pump, the upper cover 3, the barrel 4, the transparent model box 1 and the particles The uniform distribution box 2 is made of transparent materials. The shapes of the transparent model box 1 and the particle uniform distribution box 2 are both hollow cuboid structures. The inner upper part of the barrel body 4 is located directly above the transparent model box 1, the upper side of the transparent model box 1 is open, the middle of the front side of the transparent model box 1 is provided with a circular drainage hole 7, and the transparent model box 1 is provided with a front and rear edge. The rectangular water bag 8 arranged in the horizontal direction, the rectangular water bag 8 is connected with a drainage pipe 9, the water outlet end of the drainage pipe 9 is arranged on the outside of the transparent model box 1 through the circular drainage hole 7, and the water outlet end of the drainage pipe 9 is provided with a drainage pipe 9. Valve 10, the upper side and the lower side of the particle uniform distribution box 2 are both open, and the lower side of the particle uniform distribution box 2 is fixedly connected with a particle feeding plate group, the particle feeding plate group is arranged horizontally, and the front and rear sides of the particle feeding plate group are respectively It is fixedly connected to the inner walls of the front and rear sides of the barrel body 4 .

Vacuum pumps are conventional technology, not shown.

The particle feeding plate group includes an upper plate 11 and a lower plate 12, the upper plate 11 and the lower plate 12 are rectangular plates arranged horizontally, the upper plate 11 and the lower plate 12 are the same size, and the cross section of the particle uniform distribution box 2 is smaller than the upper plate. 11. The lower side of the particle uniform distribution box 2 is fixedly connected to the upper surface of the upper plate 11. The upper plate 11 corresponds to the lower plate 12 up and down. The front and rear sides are fixedly connected to the inner walls of the barrel body 4 through two horizontal connecting shafts 13 respectively, and the front and rear sides of the lower plate 12 are slidably connected to the front and rear sides of the barrel 4 through two horizontal sliding shafts 14 respectively. On the side inner wall, the front ends of the two horizontal sliding shafts 14 on the front side protrude from the front side of the barrel body 4 , the rear ends of the two horizontal sliding shafts 14 on the rear side extend out of the rear side of the barrel body 4 , and the upper plate 11 is evenly opened with Several upper throwing through holes 15 are evenly provided on the lower plate 12 with several lower throwing through holes 16. When the upper and lower plates 11 and 12 are aligned up and down, each upper throwing through hole 15 and each lower throwing through hole 16 are staggered to each other, When the lower plate 12 slides forward and is staggered from the upper plate 11 , each of the upper injection through holes 15 corresponds to each of the lower injection through holes 16 one by one up and down.

Both the upper throwing through hole 15 and the lower throwing through hole 16 are rectangular holes.

The drain pipe 9 is sealed with the circular drain hole 7 , and an air valve 17 is provided on the air extraction pipe 6 .

A test method for a visual test device for simulating the evolution of cracks in a coal mine mining roadway includes the following steps:

(1) Configure a simulated base plate in the transparent model box 1;

(2) A simulated coal seam on the top of the simulated bottom plate is arranged in the transparent model box 1;

(3) A simulated roof at the top of the simulated coal seam is arranged in the transparent model box 1;

(4) Take out the transparent model box 1 from the vacuum barrel;

(5) Apply pressure to the simulated bottom plate, simulated coal seam and simulated roof prepared in the transparent model box 1, and observe the evolution process of the simulated coal mine tunnel cracks.

Step (1) is specifically: place the transparent model box 1 in the center of the bottom of the barrel 4 of the vacuum barrel, then add the calculated volume of pore liquid into the transparent model box 1, install the upper plate 11 and the lower plate 12, and then put the particles The uniform distribution box 2 is installed on the upper surface of the upper plate 11, and the quantitative transparent soil particles are put into the particle uniform distribution box 2, and then the upper cover 3 is covered on the barrel body 4, so that the vacuum barrel is isolated from the outside world, and the vacuum pump is started. When the vacuum degree in the vacuum barrel detected by the pressure tester 5 reaches the specified value, the vacuum pump stops working, and the two horizontal sliding shafts 14 on the front side are twitched, so that the lower plate 12 slides forward for a certain distance, and the upper plate 11 and the lower plate 12 are staggered. , each upper throwing hole 15 corresponds to each lower throwing hole 16 one by one, so that the transparent soil particles are evenly scattered from the particle uniform distribution box 2 through the upper throwing hole 15 and the lower throwing hole 16 into the transparent model box In the pore liquid in 1, the transparent soil particles and the pore liquid infiltrate and merge with each other to form a simulated bottom plate.

Step (2) is specifically as follows: when the simulated bottom plate reaches a certain strength, push the two horizontal sliding shafts 14 on the front side to make the bottom plate 12 slide back and reset, the top plate 11 and the bottom plate 12 are aligned up and down, and the upper and lower plates The hole 15 and each lower throwing through hole 16 are staggered to each other, then the transparent soil particles stop falling downward, open the upper cover 3, take out the particle uniform distribution box 2 from the barrel 4, and then place the rectangular water bag 8 in the front and rear direction. In the middle of the upper surface of the bottom plate, the front side of the rectangular water bag 8 is connected to the drain pipe 9, and the drain pipe 9 passes through the circular drain hole 7, so that the water outlet end is set on the outside of the transparent model box 1, and then is added to the transparent model box 1. After calculating the volume of pore liquid, install the particle distribution box 2 on the upper surface of the upper plate 11, put quantitative transparent soil particles into the particle distribution box 2, and then cover the upper cover 3 on the barrel 4, The vacuum barrel is isolated from the outside world, and the vacuum pump is started. When the vacuum degree in the vacuum barrel detected by the pressure tester 5 reaches the specified value, the vacuum pump stops working, and the two horizontal sliding shafts 14 on the front side are twitched to make the lower plate 12 slide forward for a section. The distance between the upper plate 11 and the lower plate 12 is staggered, and each upper throwing hole 15 corresponds to each lower throwing hole 16 one by one, so that the transparent soil particles evenly pass through the upper throwing holes 15 and 16 from the particle uniform distribution box 2. The lower feeding through holes 16 are scattered into the pore liquid in the transparent model box 1, and the transparent soil particles and the pore liquid penetrate and merge with each other to form a simulated coal seam.

Step (3) is specifically as follows: when the simulated coal seam reaches a certain strength, push the two horizontal sliding shafts 14 on the front side to make the lower plate 12 slide back and reset, the upper plate 11 and the lower plate 12 are aligned up and down, and the upper plates 11 and 12 are vertically aligned. The hole 15 and each lower throwing through hole 16 are staggered to each other, then the transparent soil particles stop falling downward, open the upper cover 3, take out the particle uniform distribution box 2 from the barrel 4, and then add the calculated volume to the transparent model box 1. After that, install the particle uniform distribution box 2 on the upper surface of the upper plate 11, put quantitative transparent soil particles into the particle uniform distribution box 2, and then cover the upper cover 3 on the barrel body 4 to make the vacuum barrel Isolate from the outside world, start the vacuum pump, when the vacuum degree in the vacuum barrel detected by the pressure tester 5 reaches the specified value, the vacuum pump stops working, and the two horizontal sliding shafts 14 on the front side are twitched, so that the lower plate 12 slides forward for a certain distance, and the upper plate 12 slides forward. The plate 11 and the lower plate 12 are staggered, and each upper throwing hole 15 corresponds to each lower throwing hole 16 one by one, so that the transparent soil particles can evenly pass through the upper throwing hole 15 and the lower throwing hole from the particle uniform distribution box 2. The holes 16 are scattered into the pore liquid on the upper side of the simulated coal seam in the transparent model box 1, and the transparent soil particles and the pore liquid penetrate and merge with each other to form a simulated roof.

Step (4) is specifically as follows: when the simulated top plate reaches a certain strength, push the two horizontal sliding shafts 14 on the front side to make the lower plate 12 slide back and reset, the upper plate 11 and the lower plate 12 are aligned up and down, and the upper and lower plates The hole 15 and each lower throwing through hole 16 are staggered to each other, then the transparent soil particles stop falling downward, open the upper cover 3, take out the particle uniform distribution box 2 from the barrel 4, and then disassemble the upper plate 11 and the lower plate 12. , and then take out the transparent model box 1, and add a rectangular pressure plate to the upper side of the transparent model box 1.

Step (5) is specifically as follows: placing the transparent model box 1 on the mechanical testing machine, then discharging the water in the rectangular water bladder 8 through the drain pipe 9, starting the mechanical testing machine, and applying pressure to the transparent model box 1 to simulate a coal mine roadway Excavation, through the transparent model box 1 to observe the simulated coal mine mining roadway crack evolution.

The transparent model box 1 of the present invention is placed in the center of the inner bottom of the barrel 4 of the vacuum barrel, the particle uniform distribution box 2 is arranged directly above the transparent model box 1, and the present invention sequentially adds a certain volume of pore liquid and Quantitative transparent soil particles are used to make models of the floor, roof and coal seam, and a rectangular water bladder is used to simulate the mining roadway of the coal mine, so as to make a model of the surrounding rock structure of the mining roadway of the coal mine, so as to simulate the crack evolution of the mining roadway of the coal mine.

The synthetic transparent soil particles have similar physical and mechanical properties to the real soil, and have good transparency. Using the transparent soil experimental material to simulate the deformation and failure of the coal mine mining roadway will help us to fully grasp the crack evolution law of the coal-rock composite structure, and provide a reliable scientific basis for optimizing the roadway design and construction plan.

The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced without departing from the Any modification or partial replacement of the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims (10)

1. The visual test device for simulating the evolution of cracks in coal mining tunnels is characterized in that: comprising a vacuum barrel, a transparent model box and a particle uniform distribution box, the vacuum barrel includes an upper cover and a barrel body, and a pressure tester and an air extraction device are installed on the upper cover. Pipe, the lower end of the suction pipe extends into the vacuum barrel, and the upper end of the suction pipe is connected with a vacuum pump. The shape of the cloth box is a hollow cuboid structure. The transparent model box is fixedly installed in the bottom center of the barrel. The particle uniform distribution box is installed in the upper part of the barrel and is located directly above the transparent model box. The upper side of the transparent model box is open, and the transparent model A circular drainage hole is opened in the middle of the front side of the box, and a rectangular water bag is arranged in the transparent model box along the front and rear horizontal directions. The rectangular water bag is connected with a drainage pipe, and the outlet end of the drainage pipe passes through the circular drainage hole. On the outside of the model box, the outlet end of the drain pipe is provided with a drain valve, the upper and lower sides of the particle uniform distribution box are open, and the particle distribution box is fixedly connected to the lower side of the particle delivery plate group, which is set horizontally , the front and rear sides of the particle feeding plate group are respectively fixedly connected to the inner walls of the front and rear sides of the barrel body. 2. The visual test device for simulating the evolution of fissures in coal mine mining tunnels according to claim 1, characterized in that: the particle throwing plate group comprises an upper plate and a lower plate, and the upper plate and the lower plate are both horizontally arranged rectangular plates, and the upper plate The size of the uniform distribution box is the same as that of the lower plate, the cross section of the uniform particle distribution box is smaller than that of the upper plate, the lower side of the uniform particle distribution box is fixedly connected to the upper surface of the upper plate, the upper plate and the lower plate correspond up and down, and the lower plate is slidably arranged under the upper plate. On the barrel body, the front and rear sides of the upper plate are fixedly connected to the inner walls of the barrel body on the front and rear sides through two horizontal connecting shafts, respectively, and the front and rear sides of the lower plate are slidably connected to the barrel body through two horizontal sliding shafts. On the inner walls of the front and rear sides of the barrel, the front ends of the two horizontal sliding shafts on the front side protrude from the front side of the barrel body, and the rear ends of the two horizontal sliding shafts on the rear side extend out of the rear side of the barrel body. Throwing through holes, there are several lower throwing holes evenly on the lower plate, when the upper plate and the lower plate are aligned up and down, each upper throwing through hole and each lower throwing hole are staggered with each other, and the lower plate slides forward and is staggered from the upper plate When , each upper throwing through hole corresponds to each lower throwing through hole one by one up and down. 3 . The visual test device for simulating the evolution of cracks in a coal mine mining roadway according to claim 2 , wherein the upper throwing through hole and the lower throwing through hole are both rectangular holes. 4 . 4 . The visual test device for simulating the evolution of fissures in coal mine mining tunnels according to claim 3 , wherein the drainage pipe and the circular drainage hole are sealed and connected, and a gas valve is provided on the air extraction pipe. 5 . 5. The test method of the visual test device for simulating the evolution of cracks in coal mine mining tunnels as claimed in claim 4, characterized in that: comprising the following steps: (1) Configure the simulated base plate in the transparent model box; (2) Configure the simulated coal seam on the top of the simulated bottom plate in the transparent model box; (3) A simulated roof at the top of the simulated coal seam is arranged in the transparent model box; (4) Take out the transparent model box from the vacuum barrel; (5) Apply pressure to the simulated bottom plate, simulated coal seam and simulated roof prepared in the transparent model box, and observe the evolution process of the simulated coal mine tunnel cracks. 6 . The test method of the visual test device for simulating the evolution of cracks in coal mine mining tunnels according to claim 5 , wherein the step (1) is specifically: placing the transparent model box in the center of the bottom of the barrel of the vacuum barrel, and then placing it in the center of the bottom of the barrel of the vacuum barrel. Add the calculated volume of pore liquid into the transparent model box, install the upper plate and the lower plate, and then install the particle uniform distribution box on the upper surface of the upper plate, put the quantitative transparent soil particles into the particle uniform distribution box, and then put the upper plate The cover is placed on the barrel to isolate the vacuum barrel from the outside world, and the vacuum pump is started. When the vacuum degree in the vacuum barrel detected by the pressure tester reaches the specified value, the vacuum pump stops working, and the two horizontal sliding shafts on the front side are twitched to make the lower plate Slide forward for a certain distance, the upper plate and the lower plate are staggered, and each upper feeding through hole corresponds to each lower feeding through hole one by one, so that the transparent soil particles can evenly pass through the upper feeding through hole and the lower feeding from the particle uniform distribution box. The through holes are scattered into the pore liquid in the transparent model box, and the transparent soil particles and the pore liquid penetrate and merge with each other to form a simulated bottom plate. 7 . The test method of the visual test device for simulating the evolution of cracks in coal mining tunnels according to claim 6 , wherein step (2) is specifically: pushing the two horizontal sliding shafts on the front side to make the lower plate slide backwards. 8 . Reset, the upper plate and the lower plate are aligned up and down, and each upper feeding through hole and each lower feeding through hole are staggered to each other, open the upper cover, take out the particle distribution box from the barrel, and then place the rectangular water bag on the bottom plate along the front and rear directions. In the middle of the upper surface of the rectangular water bag, the front side of the rectangular water bag is connected to a drain pipe. The drain pipe passes through the circular drainage hole, so that the water outlet is located outside the transparent model box, and then the calculated volume of pore liquid is added to the transparent model box. Then install the particle uniform distribution box on the upper surface of the upper plate, put a quantitative amount of transparent soil particles into the particle uniform distribution box, and then cover the upper cover on the barrel to isolate the vacuum barrel from the outside world, start the vacuum pump, and when the pressure When the vacuum degree in the vacuum barrel detected by the tester reaches the specified value, the vacuum pump stops working, and the two horizontal sliding shafts on the front side are twitched to make the lower plate slide forward for a certain distance. Corresponding with each lower feeding through hole one by one, so that the transparent soil particles are uniformly scattered from the particle uniform distribution box into the pore liquid in the transparent model box through the upper feeding through hole and the lower feeding through hole, and the transparent soil particles and pore liquid are scattered. Mutual infiltration and fusion to form simulated coal seams. 8 . The test method of the visual test device for simulating the evolution of cracks in coal mine mining tunnels according to claim 7 , wherein step (3) is specifically: pushing the two horizontal sliding shafts on the front side to make the lower plate slide backwards. 9 . Reset, the upper plate and the lower plate are aligned up and down, the upper and lower injection holes are staggered, open the upper cover, take out the particle distribution box from the barrel, and then add the calculated volume to the transparent model box. Pore liquid, then install the particle uniform distribution box on the upper surface of the upper plate, put quantitative transparent soil particles into the particle uniform distribution box, and then cover the upper cover on the barrel to isolate the vacuum barrel from the outside world, and start the vacuum pump. , When the vacuum degree in the vacuum barrel detected by the pressure tester reaches the specified value, the vacuum pump stops working, and the two horizontal sliding shafts on the front side are twitched, so that the lower plate slides forward for a certain distance, the upper plate and the lower plate are staggered, and each upper plate is placed on the upper plate. The through holes correspond to each lower injection through hole one by one, so that the transparent soil particles are uniformly scattered from the particle uniform distribution box into the pore liquid on the upper side of the simulated coal seam in the transparent model box through the upper injection through holes and the lower injection through holes. , the transparent soil particles and the pore liquid interpenetrate and fuse to form a simulated roof. 9 . The test method of the visual test device for simulating the evolution of cracks in coal mining tunnels according to claim 8 , wherein step (4) is specifically: pushing the two horizontal sliding shafts on the front side to make the lower plate slide backwards. 10 . Reset, the upper plate and the lower plate are aligned up and down, the upper and lower through holes are staggered from each other, open the upper cover, take out the particle distribution box from the barrel, then disassemble the upper plate and the lower plate, and then Take out the transparent model box, and add a rectangular pressure plate to the upper side of the transparent model box. 10 . The test method of the visual test device for simulating the evolution of cracks in coal mine mining tunnels according to claim 9 , wherein step (5) is specifically: placing the transparent model box on the mechanical testing machine, and then placing the rectangular water bag in the test machine. 11 . The water is discharged through the drain pipe, the mechanical testing machine is started, and pressure is applied to the transparent model box to simulate the excavation of the coal mine roadway, and the simulated coal mine mining roadway crack evolution is observed through the transparent model box.