CN106198340A - A kind of coal seam permeability test system and method simulating pit mining - Google Patents

Abstract

A coal seam permeability test system and method for simulating mine mining. The test system includes an air intake device, a test device, and a gas collection device connected in sequence. The test device includes a cubic channel steel frame, and the left and right surfaces of the channel steel frame are sealed by an acrylic plate. The front and rear surfaces and the upper and lower surfaces of the channel steel frame are sealed by plastic film to form an internally sealed box. The end of the high-pressure pipeline passes through the acrylic plate and enters the box. The box is equipped with simulated materials similar to coal seams that are stacked. The gas entering through the high-pressure pipeline passes into the protected layer, and the test device is connected to the gas collecting device through a rubber hose to collect the permeated gas. The invention simulates the positions of the protective layer and the protected layer during mine mining, exploits the protective layer first by using experimental means, and tests the change of the permeability characteristics of the protected layer in the process, determines the effectiveness and timeliness of the mining of the protective layer, and guides The actual mining of mines.

Description

A coal seam permeability test system and method for simulating mine mining

technical field

The invention belongs to the technical field of mine mining, in particular to a coal seam permeability testing system and method for simulating mine mining.

Background technique

In the process of mine mining, the structure of coal and rock mass changes due to the mining of coal seams, and a large number of fissures are generated. The permeability characteristics of coal and rock mass in the fissure zone change significantly, affecting the accumulation of gas and the distribution of gas pressure. Gas accumulation causes mine gas disasters. Article 193 of my country's "Coal Mine Safety Regulations" stipulates that "when coal seam groups are exploited in outburst mines, measures for the prevention and control of outburst mining protective layers should be selected first." When the protective layer is mined for the first time, it is necessary to compile the protection effect and protection range investigation design of the protected layer, and carry out the actual investigation and verification of the protection effect and protection range.” To mine the protective layer, study and measure the permeability characteristics of the protected coal seam. If it meets the requirements of the "Protective Layer Mining Technical Specifications", the protected layer can be mined.

At present, the coal seam permeability test is mainly based on two methods: field test and laboratory test. For the permeability test of the protected layer under the mining condition of the protective layer, the application is seldom due to the difficulty of operation and high risk. The method of testing permeability in the laboratory cannot truly and dynamically reflect the change of coal permeability during the mining process of the protective layer, and has little guiding effect on the actual mining process, and cannot truly reflect the effect of pressure relief and permeability enhancement of the protected layer.

Therefore, it is necessary to design a better coal seam permeability testing system in the mining process to solve the above problems.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a permeability test of the protected layer under the condition of simulating the mining of the protective layer based on similar materials in the laboratory, which can dynamically test the permeability change of the protected layer and determine the mining value of the protective layer. Effectiveness and timeliness, and the test system can be recycled and reused, and a coal seam permeability test system and method for simulating mine mining with good scalability.

In order to achieve the above object, the present invention adopts the following technical solutions:

A coal seam permeability test system for simulating mine mining, comprising an air intake device, a test device, and a gas collection device connected in sequence, the air intake device includes a high-pressure gas cylinder, and the high-pressure gas cylinder is connected to the test chamber through a high-pressure pipeline. device, the test device comprises a cubic channel steel frame, the left and right surfaces of the channel steel frame are sealed by acrylic plates, the front and rear surfaces and the upper and lower surfaces of the channel steel frame are sealed by plastic films to form an internally sealed box, The end of the high-pressure pipeline passes through the acrylic plate and enters the box, and the box is equipped with simulated materials similar to coal seams stacked, wherein the protected layer is located above the protective layer, and the high-pressure pipe passes through the box. The gas entering through the channel passes into the protected layer, and the acrylic plate on the side of the protected layer away from the high-pressure pipeline allows the pipeline to pass through and is connected to the gas collecting device for collecting the permeated gas.

Furthermore, a pressure gauge and a pressure relief valve are also provided on the high-pressure pipeline to control the pressure value of the high-pressure gas entering the testing device.

Further, above and below the outside of the box, the protective layer of the simulated material similar to the coal seam is also provided.

Further, the channel steel frame is formed by a plurality of channel steel frames, and the plastic film is pre-embedded in the channel steel frame.

Further, the acrylic plate is fixed to the channel steel through pins and bolts, the pins are welded to the channel steel, and the bolts pass through the pins and are fixed on the acrylic plate.

Further, the acrylic plate is pasted with a silica gel plate towards the side of the coal seam similar to the simulated material, and the silica gel plate interferes with the protected layer.

Further, silica gel sealing strips are provided around the silica gel plate.

Further, the gas collecting device includes a water tank and a measuring cylinder, the measuring cylinder is placed upside down in the water tank, and one end of the pipeline extends into the measuring cylinder.

A method based on the above-mentioned coal seam permeability testing system for simulating mine mining, comprising: step 1: layering and arranging coal seam similar simulation materials inside and outside the box, the protective layer is located outside and inside the box, and the The protected layer is located in the box and is sandwiched by the protective layer; step 2: open the high-pressure gas cylinder to pass the gas into the box; step 3: simulate mine mining to remove the outside of the box The protective layer is used to collect the amount of gas permeated by the protective layer during the process through the gas collection device.

Further, the gas collection device measures the amount of gas by a drainage method.

Beneficial effects of the present invention:

By installing a coal seam-like simulation material in a sealed box formed by sealing acrylic plates and plastic films, the position of the protective layer and the protected layer during mine mining is simulated, and the lower protective layer is mined first by means of experiments, and the process is tested. The penetration of the protected layer can dynamically test the permeability change of the protected layer, determine the effectiveness and timeliness of the mining of the protective layer, and guide the actual mining of the mine, and the test system can be recycled and reused, with good scalability , the use of plastic film sealing can not only ensure the sealing, but also will not affect the transmission of the stress of the upper rock formation, that is, "force transmission, no air leakage".

Description of drawings

Fig. 1 is the structural representation of the coal seam permeability testing system of the simulation mine exploitation of the present invention;

In the figure, 1—high pressure cylinder, 2—pressure reducing valve, 3—pressure gauge, 4—high pressure pipeline, 5—box, 6—acrylic plate, 7—plastic film, 8—protective layer, 9—protected layer, 10—silica gel plate, 11—silica gel sealing strip, 12—pipeline, 13—sink, 14—measuring cylinder, 15—bolt, 16—bolt, 17—channel steel.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relationship between the components in a certain posture (as shown in the accompanying drawings). Relative positional relationship, movement conditions, etc., if the specific posture changes, the directional indication will also change accordingly.

As shown in Figure 1, the present invention provides a coal seam permeability test system for simulating mine mining, adding a fluid-solid coupling test device on a similar simulation material test bench, which solves the problem that the permeability characteristics of the protected seam coal body cannot be corrected during the mining process of the protective layer The technical defect of the on-site dynamic test can dynamically test the permeability change of the protected layer, determine the effectiveness and timeliness of the mining of the protective layer, and guide the actual mining of the mine. The above-mentioned coal seam permeability testing system includes an air intake device, a testing device and a gas collecting device connected in sequence.

Air intake device comprises high-pressure gas cylinder 1, and high-pressure gas is housed in high-pressure gas cylinder 1, and high-pressure gas must be nontoxic, harmless, non-explosive and easy to obtain, so in the present embodiment, what is installed in high-pressure gas cylinder 1 is high-pressure gas cylinder 1. nitrogen. The high-pressure gas cylinder 1 is connected to the test device through the high-pressure pipeline 4, and the high-pressure pipeline 4 is provided with a pressure gauge 3 and a pressure reducing valve 2. The pressure gauge 3 is used to read the pressure value of the high-pressure gas on the high-pressure pipeline 4, and decompress Valve 2 adopts YQO-09 bottled nitrogen pressure reducing valve, which is used to control the pressure value of high-pressure gas entering the test device, to ensure that the outlet pressure of high-pressure pipeline 4 is always stable, and to provide a reliable gas power source during the experiment. In order to ensure that the flow form of nitrogen in the high-pressure pipeline 4 is one-way flow, the high-pressure pipeline 4 should be arranged as straight as possible, and the cross-section of the high-pressure pipeline 4 should be as smooth as possible, so as to reduce the partial flow of gas in the high-pressure pipeline 4 resistance.

The test device includes a cubic steel channel frame, the left and right surfaces of the channel steel frame are sealed by acrylic plates 6 , the front and rear surfaces and the upper and lower surfaces of the channel steel frame are sealed by plastic films 7 to form an internally sealed box body 5 . The end of the high-pressure pipeline 4 passes through the acrylic plate 6 and enters the box body 5. The box body 5 is equipped with simulated materials similar to the coal seam stacked. The protected layer 9 is located above the protective layer 8 and enters through the high-pressure pipeline 4. The gas passes into the protected layer 9, and the acrylic plate 6 on the side away from the high-pressure pipeline 4 of the protected layer 9 allows the pipeline 12 to pass through and connect to the gas collecting device for collecting the permeated gas. A protective layer 8 of similar simulated material to the coal seam is also provided above and below the exterior of the box body 5 to simulate the positional relationship between the protective layer 8 and the protected layer 9 during mining. When selecting materials for the permeability test system, materials that can withstand high pressure should be selected to prevent the test system from "bursting" during the air intake process.

The design principle of the test device is "recycling, ensuring airtightness, and easy disassembly". The channel steel frame is formed by a plurality of channel steels 17 as the framework. The front, rear, upper and lower surfaces of the test device are evenly covered with PVC plastic films 7, which can withstand relatively large gas pressure. Buried in the model with channel steel 17 as the skeleton. In the process of model making, the PVC plastic film 7 is pre-embedded in the model. In order to ensure its characteristics of "force transmission and airtightness", the width of the PVC plastic film 7 in the up and down direction is set to be 200mm wider than the model, and at the same time, its The two sides are partially folded, so that the collapsed rock mass above the PVC plastic film 7 has more room for movement, ensuring that the experimental system "transmits force and does not leak air", and realizes the scalability of the device. The use of the plastic film 7 does not affect the transmission of stress. Since the experiment is a test of the permeability characteristics of the local protected layer, it does not affect the transmission of the stress of the overlying stratum under the condition of ensuring the sealing, and does not affect the application of the stress monitoring system.

The left and right panels of the test device are made of acrylic plates 6 with a thickness of 20 mm. In order to improve the overall strength of the test device and help to back the left and right panels, the left and right panels and the channel steel 17 are fixed by bolts 16 and latches 15 to realise. The raw material of the bolt 15 is a Q325 steel plate, and the bolt 15 is fixedly connected with the channel steel 17 by fish scale welding. The acrylic plate 6 is installed on the pin 15 through the bolt 16, and the bolt 16 passes through the pin 15 and is fixed on the acrylic plate 6 to connect the acrylic plate 6 and the channel steel 17, and at the same time, it is necessary to ensure that the acrylic plate 6 and the pin 16 and the groove Tightness between steel 17.

The tightness of the test system is crucial to the success of the entire experiment. The tightness of the test system directly affects the control of the inlet pressure and the collection of the outlet flow, and at the same time will change the flow state of the gas, so that the data processing does not meet the assumptions. , so ensuring the tightness of the test system is an important factor for the success of the experiment. In order to improve the sealing effect, the acrylic plate 6 faces the side of the coal seam similar to the simulated material and sticks the silica gel plate 10 with strong adhesive and special glue. , the silica gel plate 10 has good elasticity and can fully contact with the surface of the protected layer 9 . Preferably, a silicone sealing strip 11 is provided around the silica gel plate 10 for sealing the gap between the silica gel plate 10 and the acrylic plate 6 .

The gas collection device includes a water tank 13 and a measuring cylinder 14. The measuring cylinder 14 is placed upside down in the water tank 13, and one end of the pipeline 12 extends into the measuring cylinder 14. Through a physical collection method such as drainage and gas collection, the amount of collected gas is more accurate.

In the coal seam permeability test system for simulating mine mining of the present invention, in the similar material simulation test process, the implementation of the permeability characteristic test system of the protected layer 9 can not affect the transmission of stress and the application of the stress monitoring system, and can adapt to the endowment of different coal seams. Preservation conditions, and can realize the dynamic test of the evolution law of the penetration characteristics of the protected layer 9, with good test results, good scalability, good economic value and adaptability, the test system is easy to operate, simple and reliable , can be recycled and reused.

The present invention is based on the method of the coal seam permeability testing system of above-mentioned simulated mine mining and comprises:

Step 1: layering and arranging simulated materials similar to the coal seam inside and outside the box body 5, the protective layer 8 is located outside and inside the box body 5, the protected layer 9 is located in the box body 5, and is sandwiched by the protective layer 8;

Step 2: Open the high-pressure gas cylinder 1 to pass the gas into the box body 5;

Step 3: Simulate mine mining to remove the protective layer 8 below the box body 5, and the gas collection device collects the amount of gas permeated by the protective layer 9 in the process through the drainage and gas collection method.

The positions of the protective layer 8 and the protected layer 9 during mine mining are effectively simulated by the above method, and the lower protective layer 8 is first mined by means of experiments, and the penetration of the protected layer 9 is tested in the process to determine the mining of the protective layer 8. Effectiveness and timeliness, guide the actual mining of the mine.

The above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without Any deviation from the spirit and scope of the technical solution shall be covered by the scope of the claims of the present invention.

Claims (10)

1. A coal seam permeability testing system simulating mine mining, characterized in that it comprises: an air intake device, a test device and a gas collecting device are connected successively, the air intake device comprises a high-pressure gas cylinder, and the high-pressure gas cylinder passes through a high-pressure gas cylinder The pipeline is connected to the test device, and the test device includes a cubic channel steel frame, the left and right surfaces of the channel steel frame are sealed by acrylic plates, the front and rear surfaces and the upper and lower surfaces of the channel steel frame are sealed by a plastic film, Form an internally sealed box, the end of the high-pressure pipeline passes through the acrylic plate and enters the box, and the box is equipped with simulated materials similar to the coal seam stacked, wherein the protected layer is located in the protective layer Above, the gas entering through the high-pressure pipeline passes into the protected layer, and the acrylic plate on the side of the protected layer away from the high-pressure pipeline allows the pipeline to pass through and connect to the gas collecting device, Used to collect permeated gas. 2. The coal seam permeability test system for simulating mine mining according to claim 1, characterized in that: said high-pressure pipeline is also provided with a pressure gauge and a pressure reducing valve to control the pressure value of high-pressure gas entering said test device. 3. The coal seam permeability test system for simulating mine mining according to claim 1, characterized in that: the protective layer of the similar simulated material of the coal seam is also provided above and below the outside of the box. 4. The coal seam permeability test system for simulating mine mining according to claim 1, characterized in that: the channel steel frame is formed by a plurality of channel steels as the skeleton, and the plastic film is pre-embedded in the channel steel inside the shelf. 5. The coal seam permeability test system for simulating mine mining according to claim 4, characterized in that: said acrylic plate is fixed to said channel steel by bolts and bolts, said bolt is welded to said channel steel, said A bolt passes through the bolt and is fixed on the acrylic plate. 6. The coal seam permeability test system for simulating mine mining according to claim 1, characterized in that: the acrylic plate is pasted with a silica gel plate toward the side of the coal seam similar to the simulated material, and the silica gel plate is in conflict with the said acrylic plate. The protective layer. 7. The coal seam permeability test system for simulating mine mining according to claim 6, characterized in that: silica gel sealing strips are arranged around the silica gel plate. 8. The coal seam permeability test system for simulating mine mining according to claim 1, characterized in that: said gas collecting device comprises a water tank and a measuring cylinder, said measuring cylinder is placed upside down in said water tank, and one end of said pipeline extends into the measuring cylinder. 9. A method based on the coal seam permeability testing system for simulating mine mining according to claim 1, characterized in that it comprises: Step 1: layering and arranging coal seam similar simulation materials inside and outside the box, and the protective layer Located outside and inside the box, the protected layer is located in the box and sandwiched by the protective layer; Step 2: Open the high-pressure gas cylinder to pass gas into the box; Step 3: simulating mine mining to remove the protective layer on the outside of the box, and collect the amount of gas permeated by the protective layer during the process through the gas collection device. 10. The coal seam permeability test system for simulating mine mining according to claim 1, characterized in that: the gas collection device measures the gas volume by the drainage method.