A device and method for accurately measuring the equivalent width of gas pre-discharge in roadways

Abstract

This invention discloses a device and method for accurately measuring the equivalent width of pre-drainage gas in roadways. The device is placed inside a borehole along the bedding plane to measure the gas emission velocity. A curve showing the relationship between the gas emission velocity and the corresponding borehole depth is plotted, allowing for accurate measurement of the equivalent width of pre-drainage gas in the roadway. This method fully considers factors such as coal seam gas pressure, gas content, ground stress, burial depth, and coal permeability. Utilizing the positive correlation between gas emission velocity and the equivalent width of pre-drainage gas in the roadway, the method achieves higher accuracy and faster measurement speed. It also aligns with common knowledge in coal mine gas management and offers advantages such as short testing time, high accuracy, and simple operation, enabling the measurement results to guide on-site gas disaster management in coal mines.

Description

Technical Field

[0001] This invention belongs to the field of gas emission prediction and gas extraction technology, and specifically provides a device and method for accurately measuring the equivalent width of gas pre-drainage in roadways. Background Technology

[0002] The equivalent width of pre-drainage gas in a roadway is the depth at which gas no longer enters the roadway vertically from the coal face at a certain point in time after the roadway has been excavated. It is an important basic data on coal seam gas and is widely used in the prediction of gas emission from coal mine working faces, the evaluation of coal quantity and residual gas content in the assessment of gas drainage compliance, and the calculation of residual gas content in the area of ​​pre-drainage and recovery mining face of outburst-prone coal seams. The national standards and specifications adopted by my country's coal mines, such as the "Method for Predicting Mine Gas Outburst" (AQ1018-2006), the "Method for Predicting Mine Gas Outburst in Fully Mechanized Top Coal Caving Faces" (NB / T10364-2019), the "Method for Verifying the Effectiveness of Gas Prevention Measures in Pre-drainage Mining Faces" (MT / T1037-2019), and the "Interim Provisions on Coal Mine Gas Drainage Compliance," all require the use of the equivalent width of pre-drainage gas in roadways. Moreover, the equivalent width of pre-drainage gas in roadways is determined primarily based on actual mine measurement data. The accurate equivalent width of pre-drainage gas in roadways plays a crucial role in coal mine gas prevention and control. It is an industry consensus that the equivalent width of pre-drainage gas in roadways is directly related to factors such as coal seam gas pressure, ground stress, gas content, burial depth, coal permeability, and drainage time. However, at present, the value of the equivalent width of pre-drainage gas in roadways is mainly given by empirical values ​​or empirical formulas based on similar coal quality. This results in a large discrepancy between the calculated results and the actual situation when predicting gas emission, coal seam gas extraction, and verifying the effectiveness of anti-outburst measures, which directly affects coal mine safety and social stability. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide a device and method for accurately measuring the equivalent width of pre-drainage gas in roadways. This device and method can accurately measure the equivalent width of pre-drainage gas in roadways and has advantages such as short testing time, high accuracy, and simple operation. It can be measured under the original on-site conditions such as coal seam gas pressure, gas content, ground stress, burial depth, and coal permeability, so that the measurement results can guide the on-site gas disaster management in coal mines.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a precise measuring device for the equivalent width of pre-discharge gas in roadways, assembled in a coal seam roadway, comprising a measuring tube, a sealing capsule, a guide tube, a flow meter, a mine compressed air system connecting pipe, an air filling pipe, a three-way valve, a tee, and a pressure gauge. The guide tube is fixedly installed at one end of the measuring tube, the sealing capsule is fixedly installed on the outer wall of one end of the measuring tube, and the sealing capsule and the guide tube are located at the same end of the measuring tube. The flow meter is assembled at the other end of the measuring tube. The three ends of the tee are respectively connected to the pressure gauge, one end of the three-way valve, and the sealing capsule, and an air filling pipe is connected between the tee and the three-way valve. The other two ends of the three-way valve are respectively connected to the mine compressed air system connecting pipe and the atmospheric end, and the mine compressed air system connecting pipe is connected to the mine compressed air system.

[0005] Furthermore, the roadway sidewall of the coal seam roadway is constructed with in-seam boreholes, and the measuring tube, sealing capsule, and guide tube are located inside the in-seam boreholes. The space inside the sealing capsule of the in-seam borehole is the measuring gas chamber, and the length of the measuring gas chamber is the same as the length of the guide tube, which is 0.25m to 1m.

[0006] Furthermore, the measuring tubes are connected to each other, to the flow meter, and to the guide tube via plug-in connectors, and the plug-in connectors are equipped with sealing rings.

[0007] Furthermore, the front end of the guide tube is a closed blind end, and the tube wall of the guide tube is provided with guide holes in the axial and circumferential directions, with a number of 5 to 10 guide holes.

[0008] Furthermore, both the measuring tube and the guide tube are galvanized steel pipes, and the inflation tube is made of a soft material.

[0009] A method for accurately measuring the equivalent width of pre-gas drainage in roadways, using the aforementioned device for accurately measuring the equivalent width of pre-gas drainage in roadways, specifically includes the following steps:

[0010] a. Determine the location of in-seam drilling in the coal seam roadway based on the exposure time of the coal wall, and construct a set of in-seam drillings perpendicular to the roadway sidewall;

[0011] b. During the drilling process along the bedding plane, the drill rod should be withdrawn after each drilling distance.

[0012] c. Connect the sealing capsule, inflation tube, three-way valve, three-way valve, and mine compressed air system connecting pipeline, so that the three-way valve keeps the mine compressed air system connecting pipeline closed and the inflation tube is connected to the atmosphere. Install a guide tube at the front end of the measuring tube wrapped by the sealing capsule.

[0013] d. Insert the sealing capsule, inflation tube, and flow guide tube into the in-bedding borehole using the measuring tube. When the measuring tube can no longer go deeper, i.e., the blind end of the flow guide tube has reached the bottom of the in-bedding borehole, connect a flow meter to the outer end of the measuring tube.

[0014] e. Adjust the three-way valve to close the atmospheric end, connect the mine compressed air system connecting pipe to the air filling pipe, use the mine compressed air system to inflate the sealing capsule to the predetermined value, the sealing capsule expands to seal the borehole along the bedding, use a flow meter to measure the gas flow rate, and obtain the borehole gas emission rate q.

[0015] f. Adjust the three-way valve, close the connection pipeline of the mine compressed air system, connect the air inlet pipe to the atmospheric end, release the air from the sealing capsule, and remove the roadway pre-discharge gas equivalent width precision measuring device after the sealing capsule is loosened.

[0016] g. In the current bedding borehole, repeat steps c, d, e, and f until the borehole gas emission rate q no longer changes with the depth of the bedding borehole;

[0017] h. Plot the relationship curve between the borehole gas emission velocity q and the corresponding borehole depth along the bedding plane to obtain the equivalent width L of pre-drainage gas in the roadway based on the borehole gas emission velocity q. q .

[0018] Further, in step a, the coal seam roadway includes a solid coal excavation roadway or a coal mining roadway. The coal mining roadway includes a return airway, an intake airway, and a coal mining face. The return airway and the intake airway are located at both ends of the coal mining face. The roadway sidewalls are provided with solid roadway sidewalls, and the solid roadway sidewalls include the roadway roof and the roadway floor. Both sides of the roadway are solid coal.

[0019] During the excavation of solid coal tunnels, in-seam boreholes are set in the sidewalls of the tunnels.

[0020] During the longwall mining process, in-seam boreholes are set in the sidewalls of the return airway and the intake airway, and multiple in-seam boreholes can be operated simultaneously.

[0021] Furthermore, in step a, the construction location of the in-seam borehole is selected in a coal seam area without large geological structures such as faults and folds and without obvious cracks. It is preferable to select an area with a large burial depth and a short exposure time of the coal wall within the existing development range of the mine.

[0022] The number of the set of in-bedding boreholes shall not be less than two, the borehole spacing D shall not be less than 2m, and the in-bedding boreholes shall be arranged in the middle of the solid side of the roadway.

[0023] The bedding boreholes are horizontal or upward bedding boreholes, using a dry drilling process, with a diameter of 42mm to 133mm.

[0024] Furthermore, in step b, the certain drilling distance is the length l of the measuring gas chamber, which is precisely controlled by the length of the guide pipe. The length of the guide pipe is between 0.25m and 1m, and the length is controllable.

[0025] Furthermore, in step b, the drilling speed of the in-seam borehole is kept constant, and the drilling speed is 0.5 to 2 m / min.

[0026] The beneficial effects of using this invention are:

[0027] This invention provides a device and method for accurately measuring the equivalent width of pre-drainage gas in roadways. It fully considers factors such as coal seam gas pressure, gas content, ground stress, burial depth, and coal permeability. By utilizing the positive correlation between gas outburst velocity and the equivalent width of pre-drainage gas in roadways, the device achieves higher accuracy and faster measurement of the equivalent width of pre-drainage gas in roadways. It is also consistent with common knowledge of coal mine gas management and has the advantages of controllable and adjustable test location, short test time, high test accuracy, and simple operation. The measurement results can guide the on-site management of gas disasters in coal mines. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the precise measurement device for the equivalent width of pre-discharged gas in roadways according to the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the measurement of the width of the pre-discharge gas zone in a solid coal tunnel according to the present invention.

[0030] Figure 3 This is a cross-sectional view of the borehole arrangement along the bedding plane in this invention.

[0031] Figure 4 This is a schematic diagram illustrating the measurement of the width of the pre-discharge gas zone in the longwall mining face roadway according to the present invention.

[0032] Figure 5 This is the curve showing the relationship between the borehole gas emission velocity q and the borehole depth in Embodiment 3 of the present invention.

[0033] Figure 6 This is a curve showing the relationship between the gas emission velocity q and the borehole depth in the return airway in Embodiment 4 of the present invention.

[0034] Figure 7 This is a curve showing the relationship between the gas emission velocity q from the borehole in the intake airway and the borehole depth in Embodiment 4 of the present invention.

[0035] The reference numerals in the figures include:

[0036] 1. Solid coal mining roadway; 2. Roadway sidewall; 3. Working face; 4. In-seam borehole; 401. Measuring pipe; 402. Sealing capsule; 403. Measuring air chamber; 404. Guide pipe; 405. Flow meter; 406. Mine compressed air system connection pipeline; 407. Air filling pipe; 408. Three-way valve; 409. T-junction; 410. Pressure gauge; 5. Roadway roof; 6. Roadway floor; 7. Goaf; 8. Return airway; 9. Intake airway; 10. Longwall face. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] Reference Figure 1 A device for accurately measuring the equivalent width of pre-discharge gas in a coal seam roadway is assembled inside the roadway. It includes a measuring tube 401, a sealing capsule 402, a guide tube 404, a flow meter 405, a mine compressed air system connecting pipe 406, an air filling pipe 407, a three-way valve 408, a three-way valve 409, and a pressure gauge 410. The guide tube 404 is fixedly installed at one end of the measuring tube 401, and the sealing capsule 402 is fixedly installed on the outer wall of one end of the measuring tube 401. The sealing capsule 402 and the guide tube... Pipe 404 is located at the same end of measuring pipe 401, flow meter 405 is assembled at the other end of measuring pipe 401, the three ends of tee 409 are respectively connected to pressure gauge 410, one end of three-way valve 408 and sealing capsule 402, and an air inlet pipe 407 is connected between tee 409 and three-way valve 408. The other two ends of three-way valve 408 are respectively connected to mine compressed air system connection pipe 406 and atmospheric end, and mine compressed air system connection pipe 406 is connected to mine compressed air system.

[0040] The device for accurately measuring the equivalent width of pre-discharged gas in roadways is installed in the borehole 4 along the coal seam roadway. The flow meter 405 is used to measure the gas emission velocity q in the borehole. After plotting the curve of the gas emission velocity q in the borehole, the equivalent width of pre-discharged gas in roadways can be obtained.

[0041] Specifically, the roadway sidewall 2 of the coal seam roadway has a bedding borehole 4, and the measuring pipe 401, the sealing capsule 402 and the guide pipe 404 are located inside the bedding borehole 4. The space inside the sealing capsule 402 of the bedding borehole 4 is the measuring gas chamber 403, and the length of the measuring gas chamber 403 is the same as the length of the guide pipe 404, which is 0.25m to 1m.

[0042] The inflation and expansion of the sealing capsule 402 will seal the space between the sealing capsule 402 and the bottom of the borehole 4 in the bedding borehole 4. This space is the measuring gas chamber 403, which allows the flow meter 405 to measure the borehole gas outburst velocity at the measuring gas chamber 403 located at the depth of this bedding borehole 4, making the measurement results more accurate.

[0043] Specifically, the measuring tube 401 is connected to the measuring tube 401, the measuring tube 401 is connected to the flow meter 405, and the measuring tube 401 is connected to the guide tube 404 through plug-in connectors, and the plug-in connectors are equipped with sealing rings.

[0044] The length of this device can be increased by connecting multiple measuring tubes 401.

[0045] Specifically, the front end of the guide tube 404 is a closed blind end, and the tube wall of the guide tube 404 is provided with guide holes in the axial and circumferential directions, with a number of 5 to 10 guide holes.

[0046] After the gas reaches the measuring chamber 403, it flows into the guide pipe 404 through the guide hole, and then reaches the flow meter 405 through the measuring pipe 401.

[0047] Specifically, both the measuring tube 401 and the guide tube 404 are galvanized steel pipes, while the inflation tube 407 is made of a soft material.

[0048] Example 2

[0049] A method for accurately measuring the equivalent width of pre-gas drainage in roadways, using a device for accurately measuring the equivalent width of pre-gas drainage in roadways as proposed in Example 1, specifically includes the following steps:

[0050] a. Determine the location of the in-seam borehole in the coal seam roadway based on the exposure time of the coal wall, and construct a set of in-seam boreholes 4 perpendicular to the roadway sidewall 2;

[0051] b. During the construction of borehole 4 along the bedding plane, the drill rod is withdrawn after each drilling a certain distance.

[0052] c. Connect the sealing capsule 402, the inflation pipe 407, the three-way valve 408, the three-way valve 409, and the mine compressed air system connecting pipe 406, so that the three-way valve 408 keeps the mine compressed air system connecting pipe 406 closed and the inflation pipe 407 is connected to the atmosphere. Install the guide pipe 404 at the front end of the measuring tube 401 wrapped by the sealing capsule 402.

[0053] d. Insert the sealing capsule 402, inflation tube 407, and flow guide tube 404 into the in-seam borehole 4 using the measuring tube 401. When the measuring tube 401 can no longer go deeper, i.e. the closed blind end of the front end of the flow guide tube 404 has reached the bottom of the in-seam borehole 4, connect the flow meter 405 to the outer end of the measuring tube 401.

[0054] e. Adjust the three-way valve 408 to close the atmospheric end, connect the mine compressed air system connecting pipe 406 to the air filling pipe 407, use the mine compressed air system to inflate the sealing capsule 402 to the predetermined value, the sealing capsule 402 expands to seal the borehole 4 along the bedding, use the flow meter 405 to measure the gas flow rate, and obtain the borehole gas outburst velocity q.

[0055] f. Adjust the three-way valve 408, close the mine compressed air system connecting pipe 406, connect the air filling pipe 407 to the atmospheric end, release the air from the sealing capsule 402, and take out the roadway pre-discharge gas equivalent width precision measuring device after the sealing capsule 402 is relaxed.

[0056] g. In the current in-bedding borehole 4, repeat steps c, d, e, and f until the borehole gas emission rate q no longer changes with the depth of the in-bedding borehole 4;

[0057] h. Plot the relationship curve between the borehole gas emission velocity q and the corresponding borehole depth 4 along the bedding plane, thereby obtaining the equivalent width L of pre-drainage gas in the roadway based on the borehole gas emission velocity q. q .

[0058] Specifically, in step a, the coal seam roadway includes a solid coal excavation roadway 1 or a coal mining roadway. The coal mining roadway includes a return airway 8, an intake airway 9, and a coal mining face 10. The return airway 8 and the intake airway 9 are located at both ends of the coal mining face 10. The roadway sidewall 2 is provided with a solid roadway sidewall, which includes a roadway roof 5 and a roadway floor 6. Both sides of the roadway are solid coal.

[0059] During the excavation of the solid coal tunnel 1, the in-seam borehole 4 is set in the sidewall 2 of the solid coal tunnel 1;

[0060] During the mining of the longwall face 10, the in-seam boreholes 4 are respectively set in the sidewalls 2 of the return airway 8 and the intake airway 9, and multiple in-seam boreholes 4 can be operated simultaneously.

[0061] The inner end of the solid coal tunnel 1 is the tunneling face 3, and the corresponding position of the longwall face 10 is the goaf 7.

[0062] Specifically, in step a, the construction location of the in-seam borehole 4 is selected in a coal seam area without large geological structures such as faults and folds, and without obvious cracks. It is advisable to select an area with a large burial depth and a short exposure time of the coal wall within the existing development range of the mine.

[0063] There shall be no less than two boreholes 4 in a set, with a borehole spacing D of no less than 2m. The boreholes 4 shall be arranged in the middle of the solid side of the roadway.

[0064] The distance between borehole 4 and the roadway roof 5 and roadway floor 6 is 0.5 to 2 m.

[0065] The bedding borehole 4 is a horizontal or upward bedding borehole, using a dry drilling process. The diameter of the bedding borehole 4 is 42mm to 133mm.

[0066] Specifically, in step b, a certain drilling distance is the length l of the measuring gas chamber 403, which is precisely controlled by the length of the guide pipe 404. The length of the guide pipe 404 is between 0.25m and 1m, and the length is controllable.

[0067] Specifically, in step b, the drilling speed of the in-seam borehole 4 is kept constant, ranging from 0.5 to 2 m / min, with 1 m / min being preferable.

[0068] The following two examples illustrate the method for determining the width of the pre-discharge gas zone in roadways.

[0069] Example 3

[0070] Reference Figure 2 and Figure 3 A method for determining the width of the pre-discharge gas zone in a roadway includes the following steps:

[0071] a. During the excavation of the solid coal tunnel 1, a set of in-seam boreholes 4 are constructed vertically to the tunnel side 2 at the location corresponding to 25 days of coal wall exposure.

[0072] Among them, there are 2 in-layer boreholes 4, with a borehole diameter of 42mm. The in-layer boreholes 4 are located in the middle of the roadway roof 5 and the roadway floor 6, with a borehole spacing of 2m.

[0073] The construction location of the coal roadway borehole 4 should be selected in a coal body area without large geological structures such as faults and folds and without obvious cracks. It is advisable to select an area with a large burial depth and a short exposure time of the coal wall within the existing development range of the mine.

[0074] Both sides of the tunnel 1, which is a solid coal tunnel, are solid coal.

[0075] The in-bedding borehole 4 is a horizontal or upward in-bedding borehole, using a dry drilling process.

[0076] b. During the construction of borehole 4 along the bedding plane, the drill rod is withdrawn after drilling 0.5m.

[0077] The length of the guide tube 404 is 0.5m, which means the length l of the measuring gas chamber 403 is 0.5m.

[0078] The drilling speed of borehole 4 along the bedding plane remained consistent at 1 m / min.

[0079] c. Connect the sealing capsule 402, the inflation pipe 407, the three-way valve 408, the three-way valve 409, and the mine compressed air system connecting pipe 406, so that the three-way valve 408 keeps the mine compressed air system connecting pipe 406 closed and the inflation pipe 407 is connected to the atmosphere. Install the guide pipe 404 at the front end of the measuring tube 401 wrapped by the sealing capsule 402.

[0080] d. Insert the sealing capsule 402, inflation tube 407, and flow guide tube 404 into the in-seam borehole 4 using the measuring tube 401. When the measuring tube 401 can no longer go deeper, i.e. the closed blind end of the front end of the flow guide tube 404 has reached the bottom of the in-seam borehole 4, connect the flow meter 405 to the outer end of the measuring tube 401.

[0081] e. Adjust the three-way valve 408 to close the atmospheric end, connect the mine compressed air system connecting pipe 406 to the air filling pipe 407, use the mine compressed air system to inflate the sealing capsule 402 to the predetermined value, the sealing capsule 402 expands to seal the borehole 4 along the bedding, use the flow meter 405 to measure the gas flow rate, and obtain the borehole gas outburst velocity q.

[0082] f. Adjust the three-way valve 408, close the mine compressed air system connecting pipe 406, connect the air filling pipe 407 to the atmospheric end, release the air from the sealing capsule 402, and take out the roadway pre-discharge gas equivalent width precision measuring device after the sealing capsule 402 is relaxed.

[0083] g. In the current in-bedding borehole 4, repeat steps c, d, e, and f until the borehole gas emission rate q no longer changes with the depth of the in-bedding borehole 4;

[0084] h. Plot the relationship curve between the borehole gas emission velocity q and the corresponding borehole depth (e.g., ... Figure 5 As shown in the figure, the equivalent width L of pre-drainage gas in the roadway based on the borehole gas emission velocity q is thus obtained. q It is 6.0m;

[0085] The equivalent width L of the pre-gas drainage tunnel corresponding to 25 days of coal seam wall exposure. q That is, the width of the gas emission zone in the roadway after 25 days of roadway exposure is 6.0m.

[0086] Example 4

[0087] Reference Figure 3 and Figure 4 A method for determining the width of the pre-discharge gas zone in a roadway includes the following steps:

[0088] a. During the mining of the 10th longwall face, drill a borehole 4 along the roadway sidewall 2 at position X1 corresponding to 50 days of coal wall exposure in the return airway 8, and drill a borehole 4 along the roadway sidewall 2 at position X2 corresponding to 100 days of coal wall exposure in the intake airway 9.

[0089] Among them, there are 3 in-layer boreholes 4, with a borehole diameter of 94mm. The in-layer boreholes 4 are located in the middle of the roadway roof 5 and roadway floor 6, with a borehole spacing of 3m.

[0090] The construction location of the coal roadway borehole 4 should be selected in a coal body area without large geological structures such as faults and folds and without obvious cracks. It is advisable to select an area with a large burial depth and a short exposure time of the coal wall within the existing development range of the mine.

[0091] Both sides of the roadway in longwall face 10 are solid coal.

[0092] 4 is a horizontal or upward-facing borehole drilled along the bedding plane, using a dry drilling process.

[0093] b. During the construction of borehole 4 along the bedding plane, the drill rod shall be withdrawn after drilling 1.0m.

[0094] The length of the guide tube 404 is 1.0m, which means the length l of the measuring gas chamber 403 is 1.0m;

[0095] The drilling speed of borehole 4 along the bedding plane remained consistent at 1 m / min.

[0096] c. Connect the sealing capsule 402, the inflation pipe 407, the three-way valve 408, the three-way valve 409, and the mine compressed air system connecting pipe 406, so that the three-way valve 408 keeps the mine compressed air system connecting pipe 406 closed and the inflation pipe 407 is connected to the atmosphere. Install the guide pipe 404 at the front end of the measuring tube 401 wrapped by the sealing capsule 402.

[0097] d. Insert the sealing capsule 402, inflation tube 407, and flow guide tube 404 into the in-seam borehole 4 using the measuring tube 401. When the measuring tube 401 can no longer go deeper, i.e. the closed blind end of the front end of the flow guide tube 404 has reached the bottom of the in-seam borehole 4, connect the flow meter 405 to the outer end of the measuring tube 401.

[0098] e. Adjust the three-way valve 408 to close the atmospheric end, connect the mine compressed air system connecting pipe 406 to the air filling pipe 407, use the mine compressed air system to inflate the sealing capsule 402 to the predetermined value, the sealing capsule 402 expands to seal the borehole 4 along the bedding, use the flow meter 405 to measure the gas flow rate, and obtain the borehole gas outburst velocity q.

[0099] f. Adjust the three-way valve 408, close the mine compressed air system connecting pipe 406, connect the air filling pipe 407 to the atmospheric end, release the air from the sealing capsule 402, and take out the roadway pre-discharge gas equivalent width precision measuring device after the sealing capsule 402 is relaxed.

[0100] g. In the current in-bedding borehole 4, repeat steps c, d, e, and f until the borehole gas emission rate q no longer changes with the depth of the in-bedding borehole 4;

[0101] h. Plot the relationship curve between the borehole gas emission velocity q and the corresponding borehole depth (e.g., ... Figure 6 and Figure 7 As shown), the equivalent width L of the pre-drainage gas at location X1, corresponding to the borehole gas emission velocity q, after 50 days of exposure of the coal wall in the return airway 8, is obtained. q The width is 7.5m; the equivalent width L of the pre-drainage gas in the intake airway is calculated based on the borehole gas emission velocity q, corresponding to the location X2 of the exposed coal wall of intake airway 9 after 100 days. q It is 9.5m;

[0102] The equivalent width of the pre-discharge gas in the roadway corresponding to the exposure time of the coal seam is Lq, that is, the width of the gas emission zone in the roadway corresponding to 50 days of roadway exposure is 7.5m, and the width of the gas emission zone in the roadway corresponding to 100 days of roadway exposure is 9.5m.

[0103] This invention enables the determination of the equivalent width of pre-drainage gas in roadways under actual field conditions such as original coal seam gas pressure, gas content, ground stress, burial depth, and coal permeability. It utilizes the method of drilling along the seam in the intake and return airways during the working face mining process and measuring the borehole gas emission velocity q. Taking advantage of the clear functional relationship between q and the coal face exposure time—that is, the borehole gas emission velocity q approaches its extreme value—the original coal body state—as the borehole depth increases, the equivalent width of pre-drainage gas in roadways with different exposure times can be accurately measured. Simultaneous measurement in two roadways effectively reduces testing time, and the results are accurate and reliable, providing guidance for on-site gas disaster management in coal mines. It offers advantages such as better conformity to the physical definition of the equivalent width of pre-drainage gas in roadways, controllable and adjustable testing locations, short testing time, high accuracy, and simple operation.

[0104] The above content is only a preferred embodiment of the present invention. For those skilled in the art, many changes can be made in the specific implementation and application scope based on the concept of the present invention. As long as these changes do not depart from the concept of the present invention, they all fall within the protection scope of the present invention.

Claims

1. A method for accurately determining the equivalent width of pre-discharge gas in a roadway, using a device for accurately determining the equivalent width of pre-discharge gas in a roadway. This device is installed in a coal seam roadway and includes a measuring tube (401), a sealing capsule (402), a guide tube (404), a flow meter (405), a mine compressed air system connecting pipe (406), an air filling pipe (407), a three-way valve (408), a three-way valve (409), and a pressure gauge (410). The guide tube (404) is fixedly installed at one end of the measuring tube (401), and the sealing capsule (402) is fixedly installed on the outer wall of one end of the measuring tube (401). The sealing capsule (402) and the guide tube (404) are located at the same end of the measuring tube (401). The flow meter (405) is assembled at the other end of the measuring tube (401). The three ends of the tee (409) are respectively connected to the pressure gauge (410), one end of the three-way valve (408) and the sealing capsule (402). An air filling pipe (407) is connected between the tee (409) and the three-way valve (408). The other two ends of the three-way valve (408) are respectively connected to the mine compressed air system connection pipe (406) and the atmospheric end. The mine compressed air system connection pipe (406) is connected to the mine compressed air system. Specifically, the following steps are included: a. Determine the location of the in-seam borehole in the coal seam roadway based on the exposure time of the coal wall, and construct a set of in-seam boreholes (4) perpendicular to the roadway sidewall (2); b. During the construction of the in-seam drilling (4), the drill rod is withdrawn after each drilling distance; c. Connect the sealing capsule (402), the inflation pipe (407), the three-way valve (408), the three-way valve (409), and the mine compressed air system connecting pipe (406) so that the three-way valve (408) keeps the mine compressed air system connecting pipe (406) closed and the inflation pipe (407) connected to the atmosphere. Install the guide pipe (404) at the front end of the measuring tube (401) wrapped by the sealing capsule (402). d. Insert the sealing capsule (402), inflation tube (407), and flow guide tube (404) into the in-seam borehole (4) using the measuring tube (401). When the measuring tube (401) can no longer go deeper, i.e. the closed blind end of the front end of the flow guide tube (404) has reached the bottom of the in-seam borehole (4), connect the flow meter (405) to the outer end of the measuring tube (401). e. Adjust the three-way valve (408) to close the atmospheric end, connect the mine compressed air system connecting pipe (406) to the air filling pipe (407), use the mine compressed air system to fill the sealing capsule (402) to the predetermined value, the sealing capsule (402) expands to seal the borehole (4) along the bedding, use the flow meter (405) to measure the gas flow rate, and obtain the borehole gas outburst speed q; f. Adjust the three-way valve (408), close the mine compressed air system connecting pipe (406), connect the air filling pipe (407) to the atmospheric end, release the air from the sealing capsule (402), and take out the roadway pre-discharge gas equivalent width precision measuring device after the sealing capsule (402) is relaxed. g. In the current in-bedding borehole (4), repeat steps c, d, e, and f until the borehole gas emission rate q does not change with the depth of the in-bedding borehole (4); h. Plot the relationship curve between the borehole gas emission velocity q and the corresponding in-seam borehole (4) depth to obtain the equivalent width L of pre-drainage gas in the roadway based on the borehole gas emission velocity q. q .

2. The method for accurately determining the equivalent width of pre-drainage gas in roadways according to claim 1, characterized in that: The roadway sidewall (2) of the coal seam roadway is constructed with a bedding borehole (4), and the measuring tube (401), the sealing capsule (402) and the guide tube (404) are located inside the bedding borehole (4). The space inside the sealing capsule (402) of the bedding borehole (4) is the measuring gas chamber (403), and the length of the measuring gas chamber (403) is the same as the length of the guide tube (404), which is 0.25m~1m.

3. The method for accurately determining the equivalent width of pre-discharge gas in roadways according to claim 1, characterized in that: The measuring tube (401) is connected to the measuring tube (401), the measuring tube (401) is connected to the flow meter (405), and the measuring tube (401) is connected to the guide tube (404) through plug-in connectors, and the plug-in connectors are provided with sealing rings.

4. The method for accurately determining the equivalent width of pre-drainage gas in roadways according to claim 1, characterized in that: The front end of the guide tube (404) is a closed blind end. The guide tube (404) has guide holes in the axial and circumferential directions, and the number of guide holes is 5 to 10.

5. The method for accurately determining the equivalent width of pre-drainage gas in roadways according to claim 1, characterized in that: The measuring tube (401) and the guide tube (404) are both galvanized steel pipes, and the air inlet tube (407) is made of soft material.

6. The method for accurately determining the equivalent width of pre-drainage gas in roadways according to claim 1, characterized in that: In step a, the coal seam roadway includes a solid coal excavation roadway (1) or a coal mining roadway. The coal mining roadway includes a return airway (8), an intake airway (9), and a working face (10). The return airway (8) and the intake airway (9) are located at both ends of the working face (10). The roadway sidewall (2) is provided with a solid roadway sidewall, which includes a roadway roof (5) and a roadway floor (6). Both sides of the roadway are solid coal. During the excavation of the solid coal tunnel (1), the in-seam borehole (4) is set in the sidewall (2) of the solid coal tunnel (1). During the mining of the longwall face (10), the in-seam boreholes (4) are respectively set in the roadway sidewalls (2) of the return airway (8) and the intake airway (9), and multiple in-seam boreholes (4) can be operated simultaneously.

7. The method for accurately determining the equivalent width of pre-drainage gas in roadways according to claim 1, characterized in that: In step a, the construction location of the in-seam borehole (4) is selected in a coal seam area without large geological structures such as faults and folds and without obvious fractures; The number of the set of in-between boreholes (4) shall not be less than 2, the borehole spacing D shall not be less than 2m, and the in-between boreholes (4) shall be arranged in the middle of the solid side of the roadway; The bedding borehole (4) is a horizontal or upward bedding borehole, using a dry drilling process, and the diameter of the bedding borehole (4) is 42mm~133mm.

8. The method for accurately determining the equivalent width of pre-drainage gas in roadways according to claim 1, characterized in that: In step b, the certain drilling distance is the length of the measuring gas chamber (403). l The length of the guide tube (404) is precisely controlled. The length of the guide tube (404) is between 0.25m and 1m and the length is controllable.

9. The method for accurately determining the equivalent width of pre-drainage gas in roadways according to claim 1, characterized in that: In step b, the drilling speed of the in-seam borehole (4) remains constant, and the drilling speed is 0.5~2m / min.

Images