CN-116481996-B - Method for determining air leakage coefficient of coal mine sealing wall

Abstract

The invention relates to a method for determining an air leakage coefficient of a coal mine sealing wall, which comprises the following steps of S1, selecting a first detection point A1 and a second detection point A2 in a roadway between the coal mine sealing wall and a goaf, S2, detecting time delta t of air flow penetrating into a sealing space from the first detection point A1 to the second detection point A2, S3, calculating air quantity Q penetrating into the sealing space according to the time delta t of the air flow penetrating into the sealing space from the first detection point A1 to the second detection point A2, the distance L between the first detection point A1 and the second detection point A2 and the section area S of the roadway, S4, detecting pressure difference h at two sides of the coal mine sealing wall, and determining the air leakage coefficient k of the coal mine sealing wall according to the pressure difference h at two sides of the coal mine sealing wall and the air quantity Q obtained in the step S3. The method for determining the air leakage coefficient of the coal mine sealing wall has the advantages that the problem that the sealing effect of the coal mine sealing wall cannot be detected in the prior art is solved, and the method is simple, easy to implement and easy to operate.

Inventors

• LEI BAIWEI
• HUANG LAISHENG
• LI CHAO
• WU BING

Assignees

• 中国矿业大学(北京)

Dates

Publication Date

20260505

Application Date

20230430

Claims (7)

1. 1. A method for determining the air leakage coefficient of a coal mine sealing wall is characterized by comprising the following steps: S1, selecting two points in a roadway between a coal mine sealing wall and a goaf, wherein one point close to the coal mine sealing wall is used as a first detection point A1, and the other point far away from the coal mine sealing wall is used as a second detection point A2; s2, detecting the time delta t of the movement of the wind flow penetrating into the closed space from the first detection point A1 to the second detection point A2; S3, calculating the air quantity Q penetrating into the closed space according to the time delta t of the air flow penetrating into the closed space and moving from the first detection point A1 to the second detection point A2, wherein the air quantity Q is obtained by the formula (1): (1); wherein L is the distance between the first detection point A1 and the second detection point A2, deltat is the time of the wind flow moving from the first detection point A1 to the second detection point A2, and S is the cross-sectional area of the roadway; S4, detecting the pressure difference h at two sides of the coal mine sealing wall, and determining the air leakage coefficient k of the coal mine sealing wall according to the pressure difference h at two sides of the coal mine sealing wall and the air quantity Q obtained in the step S3; The air leakage coefficient k of the coal mine sealing wall is obtained by the formula (2): (2); Wherein Q is the air quantity penetrating into the closed space, C is the perimeter of the coal mine closed wall, h is the pressure difference of two sides of the coal mine closed wall, and d is the thickness of the coal mine closed wall.
2. 2. The method for determining the air leakage coefficient of the coal mine sealing wall according to claim 1, wherein in the step S2, the oxygen concentration at the first detection point A1 and the second detection point A2 is monitored in real time through the first oxygen concentration real-time monitoring device and the second oxygen concentration real-time monitoring device respectively to obtain a time-oxygen concentration curve at the first detection point A1 and the second detection point A2, and the time deltat of the movement of the wind current from the first detection point A1 to the second detection point A2 is determined through the curve.
3. 3. The method for determining the air leakage coefficient of the coal mine enclosure wall according to claim 2, wherein the distance between the first detection point A1 and the coal mine enclosure wall is 10-20m, the distance between the second detection point A2 and the coal mine enclosure wall is 30-40m, and the distance L between the first detection point A1 and the second detection point A2 is 20-30m.
4. 4. The method for determining the air leakage coefficient of the coal mine sealing wall according to claim 2, wherein the first oxygen concentration real-time monitoring device comprises a dust filter, a first beam tube and a gas sampling analysis assembly positioned outside the coal mine sealing wall; The gas sampling analysis assembly is connected with one end of a first beam tube, the other end of the first beam tube penetrates through the coal mine sealing wall to extend to the first detection point A1, and a dust filter is arranged at one end, far away from the gas sampling analysis assembly, of the first beam tube and used for preventing dust from entering the first beam tube.
5. 5. The method for determining the air leakage coefficient of the coal mine sealing wall according to claim 2, wherein the second oxygen concentration real-time monitoring device comprises a dust filter, a second beam tube and a gas sampling analysis assembly positioned outside the coal mine sealing wall; The gas sampling analysis assembly is connected with one end of a second beam tube, the other end of the second beam tube penetrates through the coal mine sealing wall to extend to the position of the second detection point A2, and a dust filter is arranged at one end, far away from the gas sampling analysis assembly, of the second beam tube and used for preventing dust from entering the second beam tube.
6. 6. The method for determining the air leakage coefficient of the coal mine sealing wall according to claim 4 or 5, wherein the gas sampling analysis assembly comprises: the beam tube multipath gas sampling pump is communicated with the first beam tube or the second beam tube at an air inlet and is used for extracting gas in the closed space; the air inlet of the beam tube branching box is communicated with the air outlet of the beam tube multipath gas sampling pump and is used for filtering moisture in the sampled gas; And the beam tube monitoring substation is provided with an air inlet communicated with an air outlet of the beam tube branching box and is used for analyzing the oxygen concentration in the sampled gas in real time.
7. 7. The method for determining the air leakage coefficient of the coal mine sealing wall according to claim 1, wherein in the step S4, the pressure difference h at two sides of the coal mine sealing wall is detected by a pressure difference testing device; The pressure difference testing device comprises a pressure difference testing tube and a pressure difference tester, wherein the pressure difference tester is connected with one end of the pressure difference testing tube, and the other end of the pressure difference testing tube passes through the coal mine sealing wall to enter the sealing space.

Description

Method for determining air leakage coefficient of coal mine sealing wall Technical Field The invention relates to the technical field of coal mine sealing walls, in particular to a method for determining an air leakage coefficient of a coal mine sealing wall. Background The goaf formed in the coal mining process is extremely easy to generate fire, and when the fire source in the goaf cannot be directly extinguished, in order to prevent the fire from spreading and ensure normal production of a mine, operators can normally build coal mine sealing walls in a roadway leading to the goaf, so that the goaf is sealed, and fresh air is prevented from entering the goaf. After the goaf is closed, the oxygen concentration in the goaf gradually decreases and the concentration of the inert gas gradually increases due to flame combustion. When the oxygen in the goaf is consumed, the fire source in the goaf is extinguished due to oxygen deficiency. Chinese patent document CN217152036U discloses a coal mine sealing wall which is quickly constructed, and is used for solving the problems of complex construction process and low construction efficiency of the coal mine sealing wall. Specifically, the inside of the roadway top plate, the roadway bottom plate and the roadway side is filled with flexible mould bags, the inner sides and the outer sides of the flexible mould bags are uniformly provided with shaping metal nets matched with the flexible mould bags for shaping, and shaping steel pipes are arranged on the outer sides of the shaping metal nets. The coal mine sealing wall is formed by splicing and installing the flexible mold bags, the shaping steel pipes and the shaping metal nets. The coal mine sealing wall has the defects that (1) after the coal mine sealing wall is constructed, the sealing effect of the coal mine sealing wall cannot be detected, so that whether the constructed coal mine sealing wall meets the requirements cannot be estimated, and (2) when the coal mine sealing wall is damaged under the influence of external force, operators cannot find and repair in time Therefore, it is highly desirable to provide a method for determining the air leakage coefficient of a coal mine enclosure wall, which can detect the closing effect of the coal mine enclosure wall. Disclosure of Invention First, the technical problem to be solved In view of the above-mentioned shortcomings and disadvantages of the prior art, the invention provides a method for determining the air leakage coefficient of a coal mine sealing wall, which solves the technical problem that the sealing effect of the coal mine sealing wall cannot be detected in the prior art. (II) technical scheme In order to achieve the above purpose, the main technical scheme adopted by the invention comprises the following steps: the embodiment of the invention provides a method for determining an air leakage coefficient of a coal mine sealing wall, which comprises the following steps: S1, selecting two points in a roadway between a coal mine sealing wall and a goaf, wherein one point close to the coal mine sealing wall is used as a first detection point A1, and the other point far away from the coal mine sealing wall is used as a second detection point A2; s2, detecting the time delta t of the movement of the wind flow penetrating into the closed space from the first detection point A1 to the second detection point A2; S3, calculating the air quantity Q penetrating into the closed space according to the time delta t of the air flow penetrating into the closed space, obtained in the step S2, from the first detection point A1 to the second detection point A2, wherein the air quantity Q is obtained by the formula (1): wherein L is the distance between the first detection point A1 and the second detection point A2, deltat is the time of the wind flow moving from the first detection point A1 to the second detection point A2, and S is the cross-sectional area of the roadway; s4, detecting the pressure difference h at two sides of the coal mine sealing wall, and determining the air leakage coefficient k of the coal mine sealing wall according to the pressure difference h at two sides of the coal mine sealing wall and the air quantity Q obtained in the step S3. Optionally, the air leakage coefficient k of the coal mine sealing wall is obtained by the formula (2): Wherein Q is the air quantity penetrating into the closed space, C is the perimeter of the coal mine closed wall, h is the pressure difference of two sides of the coal mine closed wall, and d is the thickness of the coal mine closed wall. Optionally, in step S2, the oxygen concentration at the first detection point A1 and the second detection point A2 is monitored in real time by the first oxygen concentration real-time monitoring device and the second oxygen concentration real-time monitoring device, so as to obtain a time-oxygen concentration curve at the first detection point A1 and the second detection point A2, and