Small angle roof coal uncovering tunnel vault small section coal uncovering technology

Abstract

The present application relates to the technical field of tunnel construction, in particular to a small-angle roof coal uncovering tunnel vault small-section coal uncovering process, comprising S1, excavating a ladder-type drilling field; S2, drilling and pumping a drainage hole; S3, setting up an extraction system; S4, performing extraction operation. The ladder-type drilling field is excavated in a limited ladder form in accordance with the overall trend of the bedding, and the drainage hole is drilled in a manner perpendicular to the step drilling surface, which can realize uniform distribution of drilling holes in the target area through drilling hole channels with approximately the same length. Since the direction of the drilling hole channel is determined, the drilling angle and depth can be quickly determined, the distance to the bedding surface can be easily predicted, the drilling speed and pressure of the drilling machine can be dynamically adjusted in advance, the construction safety is improved, the construction engineering quantity is reduced, the construction efficiency is improved, the hole completion rate is improved, and at the same time, the drilling hole channel can form a small-angle intersection with the bedding surface, so that the drainage hole can effectively contact more gas-containing bedding fissures, improve the coverage of the bedding surface area, and be beneficial to improving the mining efficiency.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, specifically to a small-section coal uncovering process for the arch of a small-angle roof coal uncovering tunnel. Background Technology

[0002] During the construction of gas-bearing highway tunnels containing coal seams, it is necessary to carry out coal uncovering operations in front of the tunnel face to improve the working environment and ensure the safe and smooth passage of the tunnel through the coal-bearing strata. Coal uncovering operations must strictly comply with relevant regulations on coal uncovering to prevent gas outbursts. Commonly used gas outburst prevention and control technologies include setting up drainage holes in the tunnel construction area to drain gas from the surrounding rock and the tunnel face.

[0003] The existing drainage holes are mostly arranged by hydraulic perforation to enhance permeability in combination with hole protection or by radial arrangement of main and auxiliary tunnels. However, existing drilling in high-stress soft coal seams in tunnels generally suffers from defects such as low hole formation rate, low construction efficiency, poor safety, poor adaptability, complex process and high cost.

[0004] For example, the Chinese invention patent "Advanced Anti-outburst Drilling and Drainage Method for High and Low Position Drilling Sites in Slowly Dipping Coal Seams of High-Speed ​​Railway Tunnels" (Announcement No. CN115977721B) discloses an advanced anti-outburst drilling and drainage method that uses hydraulic permeation to increase permeability and combines it with casing for hole protection. However, this drainage method is highly dependent on equipment and requires the construction of Drilling Site No. 1 and Drilling Site No. 2 in the main tunnel and pilot tunnel respectively. A large number of boreholes need to be drilled from Drilling Site No. 1 and Drilling Site No. 2 to the slowly dipping coal seam. The construction cost and complexity are high, the efficiency is low, and the initial construction cost is increased. In addition, it requires a large number of boreholes with long lengths and high precision requirements. The application effect is not ideal in high-stress soft coal seams. The time and labor costs of drilling construction are high, the construction efficiency is low, and the overall construction progress is affected. A Chinese invention patent (publication number CN112324489B) discloses a method for arranging boreholes for gas drainage in a large-section tunnel through a small-angle coal seam. This method involves drilling radial boreholes at the face of a pilot tunnel and installing drainage pipes for gas drainage. However, this borehole arrangement method requires the construction of a pilot tunnel. In high-stress, soft coal seams, the excavation risk and cost of the pilot tunnel are relatively high. When the coal seam thickens or thins locally, the fixed borehole spacing and extension direction may lead to insufficient gas drainage in some areas, while excessive drainage may occur in other areas, affecting the stability of the coal seam and the effectiveness of gas control. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of low borehole formation rate, low construction efficiency and poor safety in existing high-stress soft coal seam drilling and coal uncovering operations in tunnels, and to provide a small-section coal uncovering process for the arch of small-angle roof coal uncovering tunnels.

[0006] This invention provides a small-section coal uncovering process for the arch of a tunnel with a small-angle roof, comprising: S1. Excavating a stepped drilling site, wherein the stepped drilling site includes several steps arranged along the dip angle of the coal seam bedding plane, and the top surface of each step is set as an operating platform and the vertical surface is set as a drilling surface; S2. Drill drainage holes. Using the operating platform of the drilling rig station, drill several drainage holes on the drilling surface. The drainage holes are perpendicular to the drilling surface and the axes of adjacent drainage holes are parallel in the horizontal or vertical direction. The drainage holes form an equally spaced array of holes on the target coal seam. S3. Build an extraction system, seal several extraction holes and connect them to the gas extraction system, the gas extraction system is connected to a monitoring system; S4. Conduct sampling operations.

[0007] The small-angle roof coal uncovering tunnel arch small-section coal uncovering process of the present invention, by excavating a stepped drilling site in a limited step manner in accordance with the overall trend of the bedding, and drilling drainage holes perpendicular to the step drilling surface, can achieve uniform distribution of boreholes in the target area through borehole channels of approximately the same length. Since the borehole channels have approximately the same depth and definite direction, the drilling angle and depth can be quickly determined, making it easier to predict the distance to the bedding surface, dynamically adjust the drilling speed and pressure of the drilling rig in advance, improve construction safety, reduce construction workload, improve construction efficiency, and increase the hole formation rate. At the same time, the borehole channels can intersect the bedding surface at a small angle, so that the drainage holes can effectively contact more gas-containing bedding fissures, increase the coverage of the bedding surface area, and help improve mining efficiency.

[0008] Preferably, the drilling surfaces of adjacent steps are at the same height, and the extraction hole is 1-2m high on the drilling surface.

[0009] Preferably, the drilling direction of the extraction hole is inclined in accordance with the bedding plane of the coal seam, and the axis of the extraction hole intersects the bedding plane of the coal seam at a small angle of 10-30°.

[0010] Preferably, the diameter of the extraction hole is 75-115mm, the length is 20-80m, and the spacing between the extraction holes on the target coal seam is less than or equal to 4m.

[0011] Preferably, the dip angle of the stepped drilling site is parallel to the direction of the line connecting the edges of the steps, and the dip angle of the stepped drilling site deviates from the dip angle of the coal seam bedding plane by no more than ±5°.

[0012] Preferably, the drainage holes are located within a 15m long range along the coal seam direction outside the excavation outline on both sides of the tunnel main tunnel, and within a 10m vertical distance from the normal line of the excavation outline. The drainage holes are constructed using a crawler-type hydraulic tunnel drilling rig.

[0013] Preferably, the number of stepped drilling sites is one or more.

[0014] Preferably, in S3, the sealing includes sealing the hole by pumping polyurethane or M425 cement mortar. When the drainage hole is a rock hole, the sealing length is ≥5m, and when the drainage hole is a coal hole, the sealing length is ≥8m.

[0015] Preferably, the gas extraction system includes an extraction station, a main extraction pipeline, and branch extraction pipelines. The main extraction pipeline is suspended in the tunnel by a support frame. The branch extraction pipelines connect the extraction hole and the main extraction pipeline, and valves are installed on the branch extraction pipelines.

[0016] Preferably, the monitoring system sets up several monitoring points inside and outside the tunnel. The monitoring points are equipped with automatic monitoring mechanisms and / or manual detection mechanisms. The automatic monitoring mechanism includes a V-cone flow meter and a gas concentration sensor. The manual detection mechanism includes a detection port and a gas pipeline drainage parameter measuring instrument. The automatic monitoring mechanism is connected to the tunnel safety monitoring system.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a small-section coal uncovering process for the arch of a small-angle roof coal uncovering tunnel. By excavating a stepped drilling site in a limited step manner in accordance with the overall direction of the bedding, and drilling drainage holes in a manner perpendicular to the step drilling surface, it is possible to achieve uniform distribution of boreholes in the target area through drilling channels of approximately the same length. 2. This invention provides a small-section coal uncovering process for the arch of a small-angle roof coal uncovering tunnel. Since the drilling channels have roughly the same depth and the direction is determined, the drilling angle and depth can be quickly determined, which makes it easier to predict the distance to the bedding plane, dynamically adjust the drilling speed and pressure of the drilling rig in advance, improve construction safety, reduce the amount of construction work, improve construction efficiency, and increase the hole formation rate. 3. This invention provides a small-section coal uncovering process for the arch of a small-angle roof coal uncovering tunnel. By forming a small-angle intersection between the borehole channel and the bedding plane, the drainage hole can effectively contact more gas-containing bedding fissures, improve the coverage of the bedding plane area, and help improve mining efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process for revealing coal in a small section of the tunnel arch at a small angle roof, as described in Example 1.

[0019] Figure 2 This is a side view of the stepped drilling and drainage holes described in Example 1.

[0020] Figure 3 This is a schematic diagram of the final hole state on the bedding plane of the extraction hole described in Example 1.

[0021] Figure 4 This is a schematic diagram of the drilling of the extraction hole described in Example 1.

[0022] Figure 5 This is a schematic diagram of the gas extraction system described in Example 1.

[0023] Marked in the image: 1-Operating platform, 2-Drill face, 3-Drainage hole, 4-Coal seam bedding plane, 5-Tunnel, 6-Drainage branch pipe, 7-Valve. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0025] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0026] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0027] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0028] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0029] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0030] Example 1 like Figures 1-5 As shown, the small-section coal uncovering process of the tunnel arch with a small-angle roof includes the following steps: S1. Excavate a stepped drilling site. The stepped drilling site includes several steps set along the bedding plane 4 of the coal seam at an angle of dip. The top surface of each step is set as the operating platform 1, and the vertical surface is set as the drilling surface 2.

[0031] In an optional embodiment, the drilling surfaces 2 of adjacent steps are at the same height, the dip angle of the stepped drilling site is parallel to the direction of the line connecting the edges of several steps, the dip angle of the stepped drilling site deviates from the dip angle of the coal seam bedding plane 4 by no more than ±5°, the stepped drilling site is designed according to the coal seam dip angle, the dip angle of the stepped drilling site is approximately the same as the dip angle of the bedding plane, when drilling, the length of the drilling channel on each step is approximately the same, the drilling channels are basically parallel to each other and the drilling depth is approximately the same, and the axis of the drilling channel intersects the coal seam bedding plane 4 at a small angle of 10-30°.

[0032] In an optional implementation, there may be one or more stepped drilling sites. One or two stepped drilling sites can be set up according to actual conditions, with each stepped drilling site having the same step height and similar drilling depth. This allows for efficient and high-quality drilling of the extraction holes 3 within each stepped drilling site, improving construction efficiency. Furthermore, multiple stepped drilling sites can be set up according to actual conditions, reducing the relative area of ​​each stepped drilling site and enabling small-section coal seam exposure.

[0033] S2. Drill drainage holes 3. Using the drilling rig station operation platform 1, drill several drainage holes 3 on the drilling surface 2. The drainage holes 3 are perpendicular to the drilling surface 2, and the axes of adjacent drainage holes 3 are parallel in the horizontal or vertical direction. The drainage holes 3 form a drill hole array with equal spacing on the target coal seam.

[0034] In an optional embodiment, the drainage holes 3 are positioned at a height of 1-2m on the borehole surface 2, with uniform spacing between holes, and the borehole channels are parallel to each other and have the same depth. By uniformly distributing the drainage holes 3, comprehensive coverage of the entire bedding plane area with small angles can be ensured, improving mining efficiency. By making the borehole channels parallel to each other and of similar depth, multiple boreholes can be evenly distributed on the same layer of the bedding plane, effectively draining the gas from that layer. Moreover, because the boreholes are parallel, construction is relatively simple and convenient for management and operation.

[0035] In an optional embodiment, the drilling direction of the drainage hole 3 is inclined in accordance with the dip direction of the coal seam bedding plane 4. For example, in coal seam gas drainage, if the bedding plane dips southeast at an angle of 10°-30°, the drilling direction can be appropriately inclined southeast while ensuring a small angle intersection with the bedding plane. This allows the borehole to extend better along the bedding plane and effectively contact more gas-bearing bedding fractures.

[0036] In an optional embodiment, the diameter of the extraction hole 3 is 75-115mm and the length is 20-80m. The spacing between the holes is determined according to the actual effective extraction radius of the coal seam. Preferably, the spacing between the extraction holes 3 on the target coal seam is less than or equal to 4m, and more preferably 4*4m.

[0037] In an optional embodiment, the drainage holes 3 are arranged within a range of 15m in length along the coal seam direction outside the excavation outline on both sides of the main tunnel of tunnel 5 and 10m above and below the normal line of the excavation outline. The drainage holes 3 are constructed using a crawler-type hydraulic tunnel drilling rig.

[0038] In an optional implementation, a drainage hole 3 with a length of not less than 60m can be added to the drilled surface 2 according to the actual situation.

[0039] In an optional implementation, a ZDY or ZY series drilling rig can be selected, along with reasonable drilling parameters. The appropriate drilling method can be chosen according to the specific conditions of the coal seam, and the drilling speed and pressure can be controlled to effectively avoid borehole collapse or blockage caused by drilling too fast or too slow, thus effectively controlling the risk of borehole collapse.

[0040] S3. Set up an extraction system, seal several extraction holes 3 and connect them to the gas extraction system. The gas extraction system is connected to a monitoring system.

[0041] In an optional embodiment, the sealing of the hole includes pumping polyurethane or M425 cement mortar to seal the hole. When the drainage hole 3 is a rock hole, the sealing length is ≥5m, and when the drainage hole 3 is a coal hole, the sealing length is ≥8m.

[0042] In one or more embodiments, the gas extraction system includes an extraction station, a main extraction pipeline, and extraction branch pipes 6. The main extraction pipeline is suspended in the tunnel by a support frame. The extraction branch pipes 6 connect the extraction hole 3 and the main extraction pipeline. Valves 7 are installed on the extraction branch pipes 6.

[0043] In an optional implementation, the extraction station can be equipped with a double water ring vacuum pump station. The main extraction pipeline can be a DN200mm pipe. After the extraction hole 3 is drilled and sealed, a DN50mm mining hose can be used to connect the extraction hole 3 to the gas collection pipe at the drilling site. The connection is secured with wire. The gas collection pipe is then connected to the extraction branch pipe 6. A valve 7 is installed at the connection to control the extraction negative pressure. The gas collection pipe is then connected to the main extraction pipeline.

[0044] In an optional implementation, the gas extraction system pipeline starts from the extraction station, and is laid on the ground from the pump station to the tunnel entrance. From the tunnel entrance, it is laid inside tunnel 5. Inside tunnel 5, it can be laid by suspension, using anchor bolts to suspend it from the top of the roadway.

[0045] In one or more embodiments, the monitoring system sets up several monitoring points inside and outside the tunnel. The monitoring points are equipped with automatic monitoring mechanisms and / or manual detection mechanisms. The automatic monitoring mechanisms include V-cone flow meters and gas concentration sensors, and the manual detection mechanisms include detection ports and gas pipeline drainage parameter measuring instruments. The automatic monitoring mechanisms are connected to the tunnel 5 safety monitoring system.

[0046] In an optional implementation, a comprehensive extraction parameter detection method combining automatic monitoring and manual inspection can be adopted inside the tunnel. Two automatic monitoring points can be set up inside the tunnel, each equipped with a V-cone flowmeter, and a manual inspection port can be set up with an orifice plate flowmeter. WGCB gas pipeline extraction parameter measuring instrument can be used to check parameters such as gas concentration, extraction negative pressure, pressure difference, and temperature in the pipeline. At the same time, an automatic monitoring device with a V-cone flowmeter can be installed on the ground outside the tunnel, working in conjunction with a gas concentration sensor to monitor gas extraction parameters in real time. This device can be connected to the existing Tunnel 5 safety monitoring system to achieve real-time monitoring and query of the ground extraction system, ensuring construction safety.

[0047] S4. Conduct sampling operations.

[0048] In an optional implementation, during the excavation process after extraction, if the working face is predicted to have a prominent risk, gas can be directly discharged through boreholes to ensure excavation safety.

[0049] The small-angle roof coal uncovering tunnel arch small-section coal uncovering process of this embodiment has the following advantages compared with the prior art: (1) Improve safety: Because the drilling site is stepped, the drilling channel has a consistent depth, which makes it easy to predict the distance to the bedding plane and adjust the drilling speed and pressure of the drilling rig in advance, thus improving safety. In conjunction with gas extraction monitoring and control, the surface and tunnel 5 extraction parameters are monitored, which can realize the monitoring and control of pump station extraction metering, equipment operation status and working conditions, system parameters, and underground pipeline extraction parameters, which greatly improves the safety of engineering construction. (2) Improve work efficiency: Due to the adoption of a stepped drilling site and the drilling of drainage holes 2 perpendicular to the drilling surface 3, the length of the drilling pipeline is consistent, which can reduce the amount of construction work. The adoption of centralized station construction and the establishment of a high negative pressure gas extraction system can improve the concentration and efficiency of gas extraction, ensure the continuity and stability of gas extraction, and reduce the difficulty and time of construction. (3) Save time: The overall dip angle of the stepped drilling site is roughly consistent with the bedding plane, and the drilling is vertical. The angle can be quickly determined during drilling, saving time, improving the flexibility and efficiency of construction, reducing resource waste, and ensuring the economy and feasibility of the project.

[0050] Taking a tunnel construction project as an example, the small-angle roof coal uncovering tunnel 5-arch small-section coal uncovering technology of this embodiment improves the borehole formation rate to >95% and reduces the borehole collapse rate to <3%; construction efficiency is improved by about 30%, and drilling time is reduced by an average of 2 to 3 hours per borehole; gas extraction concentration is increased by 15 to 20%, and extraction coverage is more uniform; it is suitable for sections with different dip angles and bedding changes; it can reduce drilling, reduce equipment, save energy, achieve cost control, and significantly reduce safety risks, and enable full-process monitoring and control.

[0051] The small-angle roof coal uncovering tunnel arch small-section coal uncovering process of this embodiment excavates a stepped drilling site in a limited step manner in accordance with the overall trend of the bedding. The drainage holes 3 are drilled perpendicular to the step drilling surface 2. The drilling channels of approximately the same length can achieve uniform distribution of the boreholes in the target area. Since the depth of the drilling channels is approximately the same and the direction is determined, the drilling angle and depth can be quickly determined, which makes it easier to predict the distance to the bedding surface and dynamically adjust the drilling speed and pressure of the drilling rig in advance, improve construction safety, reduce the amount of construction work, improve construction efficiency, and increase the hole formation rate. At the same time, the drilling channels can intersect the bedding surface at a small angle, so that the drainage holes 3 can effectively contact more gas-containing bedding fissures, improve the coverage of the bedding surface area, which is conducive to improving mining efficiency and enhancing adaptability to different geological conditions, especially the adaptability to high-stress soft coal seams, and ensuring the stability and reliability of the drilling process.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A small-section coal uncovering process for the arch of a tunnel with a small-angle roof, characterized in that: include: S1. Excavate a stepped drilling site, the stepped drilling site including several steps set along the dip angle of the coal seam bedding plane (4), the top surface of each step is set as an operating platform (1), and the vertical surface is set as a drilling surface (2). S2. Drill drainage holes (3). Using the drilling rig station, the operating platform (1) is used to drill several drainage holes (3) on the drilling surface (2). The drainage holes (3) are perpendicular to the drilling surface (2), and the axes of the drainage holes (3) are parallel to each other in the horizontal or vertical direction. The drainage holes (3) form a drill hole array with equal spacing on the target coal seam. S3. Build an extraction system, seal several extraction holes (3) and connect them to the gas extraction system, the gas extraction system is connected to a monitoring system; S4. Conduct sampling operations; The drilling surfaces (2) of adjacent steps are at the same height, and the extraction hole (3) is 1-2m high on the drilling surface (2); The drilling direction of the extraction hole (3) is inclined in accordance with the bedding plane (4) of the coal seam, and the axis of the extraction hole (3) intersects the bedding plane (4) of the coal seam at an angle of 10-30°. The dip angle of the stepped drilling site is parallel to the direction of the line connecting the edges of the steps, and the dip angle of the stepped drilling site deviates from the dip angle of the coal seam bedding plane (4) by no more than ±5°.

2. The small-angle roof coal uncovering tunnel arch small-section coal uncovering process according to claim 1, characterized in that, The diameter of the extraction hole (3) is 75-115mm and the length is 20-80m. The spacing between the extraction holes (3) on the target coal seam is less than or equal to 4m.

3. The small-angle roof coal uncovering tunnel arch small-section coal uncovering process according to claim 1, characterized in that, The drainage holes (3) are located 15m long along the coal seam direction outside the excavation outline on both sides of the main tunnel (5) and 10m above and below the normal line of the excavation outline. The drainage holes (3) are constructed using a crawler-type hydraulic tunnel drilling rig.

4. The small-angle roof coal uncovering tunnel arch small-section coal uncovering process according to claim 1, characterized in that, The number of stepped drilling sites is one or more.

5. The small-angle roof coal uncovering tunnel arch small-section coal uncovering technology according to any one of claims 1-4, characterized in that, In S3, the sealing of the hole includes sealing the hole by pumping polyurethane or M425 cement mortar. When the drainage hole (3) is a rock hole, the sealing length is ≥5m. When the drainage hole (3) is a coal hole, the sealing length is ≥8m.

6. The small-angle roof coal uncovering tunnel arch small-section coal uncovering process according to claim 5, characterized in that, The gas extraction system includes an extraction station, a main extraction pipeline and extraction branch pipes (6). The main extraction pipeline is suspended in the tunnel by a support frame. The extraction branch pipes (6) connect the extraction hole (3) and the main extraction pipeline. Valves (7) are installed on the extraction branch pipes (6).

7. The small-angle roof coal uncovering tunnel arch small-section coal uncovering process according to claim 5, characterized in that, The monitoring system sets up several monitoring points inside and outside the tunnel. The monitoring points are equipped with automatic monitoring mechanisms and / or manual detection mechanisms. The automatic monitoring mechanism includes a V-cone flow meter and a gas concentration sensor. The manual detection mechanism includes a detection port and a gas pipeline drainage parameter measuring instrument. The automatic monitoring mechanism is connected to the tunnel (5) safety monitoring system.

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