A high-gas-outburst coal seam water tunnel lining structure and method with hydraulic self-closing function

Abstract

The application discloses a high-gas-outburst coal stratum water conveying tunnel lining structure with hydraulic self-closing function and a method, and belongs to the technical field of water conveying tunnel gas treatment, which comprises an outer layer primary support lining structure, a circumferential gas collecting interlayer and an inner layer secondary lining structure which are sequentially arranged from a gas-containing coal seam to the center of the water conveying tunnel, and a gas guide and discharge main pipe is arranged in the circumferential gas collecting interlayer. The outer layer primary support lining structure preliminarily supports the high-gas-outburst coal stratum, resists the stress of surrounding rock, makes the overflowed gas enter the circumferential gas collecting interlayer, is uniformly discharged through the gas guide and discharge main pipe, and avoids the safety hidden danger caused by gas accumulation; the inner layer secondary lining structure serves as the final bearing sealing barrier, bears the water pressure in the water conveying tunnel, forms a water seal barrier in the inner layer secondary lining structure, and blocks the gas leakage to the water conveying tunnel.

Description

Technical Field

[0001] This invention belongs to the field of gas control technology for water conveyance tunnels, and particularly relates to a lining structure and method for water conveyance tunnels in high-gas coal-outburst strata with hydraulic self-sealing function. Background Technology

[0002] During the long-term operation of water conveyance tunnels traversing gas-bearing coal seams, the tunnels are filled with high-pressure water flow. The lining must withstand enormous internal water expansion and cracking pressure. External high ground stress and alternating water pressure loads also cause the slow expansion of primary fractures in the surrounding coal seam, prompting gas desorption and migration towards the excavation face. Gas seeps into the tunnel through lining cracks or construction joints, easily accumulating in large quantities at local high points such as the tunnel arch, forming high-pressure gas pockets. When the water flow fluctuates, the gas pockets rupture under pressure, inducing a highly destructive water hammer effect that directly tears apart the lining concrete. Simultaneously, under high pressure, a large amount of gas dissolves in the transported water, releasing instantaneously upon reaching downstream low-pressure pumping stations or water plants, easily triggering uncontrollable secondary explosions.

[0003] When the water conveyance tunnel is shut down for regular maintenance, the water pressure support inside the tunnel drops to zero instantly. At this time, the high-pressure gas that has accumulated on the outside of the lining due to long-term blockage cannot be released. The huge reverse pressure difference can easily break through the lining anti-seepage system, and even induce delayed coal and gas outburst dynamic disasters in the empty tunnel, seriously threatening the lives of maintenance personnel.

[0004] Therefore, a water conveyance tunnel lining scheme that is suitable for high-gas coal-bearing strata and has both active drainage and self-sealing protection capabilities is needed to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a lining structure and method for water conveyance tunnels in high-gas coal-outburst strata with hydraulic self-sealing function.

[0006] The present invention is achieved through the following technical solutions.

[0007] The present invention provides a lining structure for a water conveyance tunnel in a high-gas coal-bearing stratum with hydraulic self-sealing function, comprising an outer primary support lining structure, a circumferential gas gathering interlayer, and an inner secondary lining structure arranged sequentially from the gas-bearing coal seam to the center of the water conveyance tunnel, wherein a gas drainage main pipe is arranged in the circumferential gas gathering interlayer.

[0008] Preferably, the outer initial support lining structure is set close to the excavation outline of the gas-bearing coal seam; The circumferential gas collecting interlayer is disposed between the outer primary support lining structure and the inner secondary lining structure. The inner secondary lining structure has capillary pores. The gas exhaust main is provided with several radially arranged gas exhaust pipes and longitudinally arranged gas exhaust straight pipes.

[0009] Preferably, the gas exhaust pipe passes through the outer primary support lining structure, with its front end inserted into the gas-containing coal seam and its tail end extending into the circumferential gas collecting interlayer and converging to the gas exhaust straight pipe. The gas exhaust pipe is installed in the circumferential gas collection interlayer at the arch of the water conveyance tunnel, and the exhaust end of the gas exhaust pipe is connected to the downwind outlet of the tunnel ventilation equipment installed on the inner wall of the inner secondary lining structure.

[0010] Preferably, the gas drainage pipe is wrapped with an anti-clogging filter screen on the outside of the pipe section inserted into the gas-containing coal seam; The gas exhaust main is arched upwards along the inner wall of the water conveyance tunnel. The lower end of the gas exhaust main is closed, and its exhaust port is connected to a gas exhaust straight pipe that runs along the axis of the water conveyance tunnel, so that the axis of the gas exhaust straight pipe is aligned with the wind direction of the tunnel ventilation equipment.

[0011] Preferably, the multiple gas drainage pipes are arranged in a fan-shaped, non-full-section manner, and are respectively deployed in the arch, waist, and sidewall areas of the water conveyance tunnel.

[0012] Preferably, the center distance between the tail ends of adjacent gas exhaust pipes connected to the gas exhaust straight pipe is no more than 0.5m, and the gas exhaust pipe is provided with a high-pressure backwashing interface, which penetrates the inner secondary lining structure radially.

[0013] Preferably, the inner secondary lining structure is made of permeable concrete, and the porosity of the inner secondary lining structure is 10% to 20% based on capillary porosity.

[0014] Preferably, a separation plate is laid between the outer primary lining structure and the inner secondary lining structure; The isolation plate is located within the circumferential gas collection layer. The isolation plate includes a substrate and bosses provided on the substrate. The substrate is provided with vent holes.

[0015] Preferably, a multi-field coupling monitoring and early warning system is provided in the circumferential gas collection layer. The multi-field coupling monitoring and early warning system includes a strain sensor attached to the inner surface of the outer primary support lining structure, a gas pressure concentration sensor arranged on the outer side of the substrate of the isolation plate, a humidity sensor attached to the outer surface of the inner secondary lining structure, and a gas flow sensor installed in the gas exhaust straight pipe.

[0016] A construction and operation method for a water conveyance tunnel lining structure with hydraulic self-sealing function in high-gas coal-outburst strata includes the following steps: S1: After the working face of the water conveyance tunnel is excavated, pressure relief holes are drilled into the gas-bearing coal seam and gas drainage pipes are driven in, and the holes are sealed at the opening section. S2: The excavation outline of the water conveyance tunnel is initially sealed, and the tail end of the gas drainage pipe is protected by a casing. It penetrates the initial support concrete attached to the inner wall of the water conveyance tunnel and leaves an exposed joint section on the inner side of the water conveyance tunnel. Initial concrete is sprayed onto the initial support concrete to form the outer initial support lining structure. S3: Lay an isolation plate along the inner surface of the outer primary support lining structure, install a strain sensor on the inner surface of the outer primary support lining structure, install a gas pressure concentration sensor on the outer side of the base plate of the isolation plate, and lead out the cables of the strain sensor and the gas pressure concentration sensor. S4: Tie the skeleton used to prepare the inner secondary lining structure, tie the humidity sensor to the skeleton near the isolation plate, lead out the cable of the humidity sensor, pour concrete on the skeleton to form the circumferential air collection layer and the inner secondary lining structure, and complete the construction. S5: When the water conveyance tunnel is put into operation, a stepped, slow water filling process is used to increase the internal water pressure of the water conveyance tunnel, so that water fills the capillary pores and forms a continuous liquid water film on the outer wall of the inner secondary lining structure, thus activating the hydraulic sealing barrier.

[0017] The beneficial effects of this invention are as follows: 1. This invention is applicable as the lining structure of water conveyance tunnels in high-gas coal-bearing strata. It has a hydraulic self-sealing function, realizing proactive and long-term prevention and control of gas risks in water conveyance tunnels in gas-bearing coal seam sections during operation. It uses the high internal water pressure of the water conveyance tunnel itself to force the water flow to fill the capillary pores, and forms a continuous liquid water film by means of the surface tension of the water, blocking the path of gas infiltration into the conveyed water, eliminating water hammer tearing damage induced by the arch airbag during the operation of the water conveyance tunnel and secondary explosions in downstream water plants.

[0018] 2. This invention uses a gas drainage pipe deeply inserted into the gas-bearing coal seam for active depressurization and extraction. At the same time, it utilizes a circumferential gas gathering interlayer to provide a buffer space for the escaping gas. The high-pressure gas enters the pipeline system formed by the gas drainage main pipe, gas drainage pipe and gas exhaust straight pipe under negative pressure, fundamentally eliminating the risk of structural splitting caused by long-term high-pressure gas accumulation.

[0019] 3. This invention utilizes the internal water pressure of the water conveyance tunnel to allow water to flow through capillary pores to the outside of the inner secondary lining structure for infiltration. Under the action of water pressure, water molecules preferentially occupy the gas seepage channels, forming a water seal barrier to prevent gas from overflowing into the water conveyance tunnel.

[0020] 4. This invention constructs a multi-field coupled intelligent monitoring system for the entire life cycle of water conveyance tunnels. It can monitor sudden disasters caused by excavation and unloading during construction, capture fault activation under long-term high-pressure water action through strain sensors during the operation of water conveyance tunnels, and monitor the health of water seal barriers through bidirectional comparison of air pressure and water pressure.

[0021] 5. This invention addresses the pain points of deep unloading and pulverized coal blockage by setting up a circumferential gas collection interlayer, providing redundant channels for gas flow around the gas. Combined with a reserved high-pressure backwashing interface, it achieves a self-healing effect for the pipeline system. Gas sealing relies on natural potential energy and the existing ventilation flow field, achieving a high degree of unity between safety, reliability, and economy. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a side view structural diagram of the present invention.

[0023] In the diagram: 1-Gas-bearing coal seam, 2-Outer primary support lining structure, 3-Circumferential gas gathering interlayer, 4-Gas main exhaust pipe, 5-Inner secondary lining structure, 6-Capillary pores, 7-Gas exhaust pipe, 8-Gas exhaust straight pipe, 9-Tunnel ventilation equipment, 10-Isolation plate, 11-Strain sensor, 12-Gas pressure concentration sensor, 13-Humidity sensor, 14-Gas flow sensor, 15-High-pressure backwashing interface. Detailed Implementation

[0024] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0025] Example: like Figure 1-2 As shown, a lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function includes, with the radial direction of the water conveyance tunnel as the reference, an outer primary support lining structure 2, a circumferential gas gathering interlayer 3, and an inner secondary lining structure 5 arranged sequentially from the gas-bearing coal seam 1 towards the center of the water conveyance tunnel. The radial reserved width of the circumferential gas gathering interlayer 3 is 50 mm to 150 mm, which serves as a physical reserved space for burying and accommodating the gas exhaust manifold 4, the gas exhaust straight pipe 8, and various sensors of the multi-field coupled monitoring and early warning system; providing gas buffering and flow redundancy space; when the gas exhaust pipe 7 is blocked, gas is allowed to flow circumferentially in this space to other pipelines for discharge, realizing structural redundancy flow guidance; playing a construction isolation role, and working with the isolation plate 10 to effectively prevent concrete extrusion during the pouring of the inner secondary lining structure 5, thereby preventing blockage of the gas gathering channel; the gas exhaust manifold 4 is installed inside the circumferential gas gathering interlayer 3.

[0026] The outer primary support lining structure 2 is set close to the excavation outline of the gas-bearing coal seam 1 and is poured with P12 grade high impermeability concrete to initially seal the gas and groundwater in the gas-bearing coal seam 1. The circumferential gas collection interlayer 3 is disposed between the outer primary support lining structure 2 and the inner secondary lining structure 5, and is used to collect the gas that escapes through the outer primary support lining structure 2. The inner secondary lining structure 5 is made of permeable concrete and has microscopic capillary pores 6 inside. The gas exhaust main duct 4 is provided with several radially arranged gas exhaust pipes 7 and longitudinally arranged gas exhaust straight pipes 8.

[0027] The gas drainage pipe 7 is installed through the outer primary support lining structure 2. Its front end is inserted into the gas-containing coal seam 1 through a deep hole to actively depressurize and collect gas. Its tail end extends into the circumferential gas collection interlayer 3 and is connected to the gas exhaust straight pipe 8. The gas exhaust pipe 8 is installed in the circumferential gas collection interlayer 3 at the arch of the water conveyance tunnel, and the exhaust end of the gas exhaust pipe 8 is connected to the downwind port of the tunnel ventilation equipment 9 installed on the inner wall of the inner secondary lining structure 5, forming a negative pressure extraction network. The tunnel ventilation equipment 9 is electrically connected to the control system.

[0028] The gas drainage pipe 7 is inserted into the gas-containing coal seam 1 and the outside of the pipe section is wrapped with an anti-clogging filter screen to prevent coal debris and rock powder in the borehole from clogging the pipe. The gas drainage main pipe 4 is arched upward along the inner wall of the water conveyance tunnel. The lower end of the gas drainage main pipe 4 is closed, and its exhaust port is located at the top of the water conveyance tunnel and downwind of the tunnel ventilation equipment 9. A gas exhaust straight pipe 8 is connected to the exhaust port and is arranged along the axis of the water conveyance tunnel. The axis of the gas exhaust straight pipe 8 is arranged in the wind direction of the tunnel ventilation equipment 9. The negative pressure generated at the exhaust port of the gas drainage main pipe 4 by the tunnel ventilation equipment 9 is used to drain the gas through the pipeline network system formed by the gas drainage main pipe 4, the gas drainage pipe 7 and the gas exhaust straight pipe 8.

[0029] The multiple gas drainage pipes 7 are arranged in a fan-shaped, non-full-section configuration, and are mainly deployed in the arch, waist, and sidewall areas of the water conveyance tunnel, which are most severely affected by the excavation and unloading disturbance of the water conveyance tunnel and are prone to gas outbursts.

[0030] The center distance between the tail ends of adjacent gas exhaust pipes 7 connected to the gas exhaust straight pipe 8 is no more than 0.5m to ensure uniform distribution of negative pressure during extraction; a high-pressure backwashing interface 15 is provided on the bypass at the end of the gas exhaust pipe 4, the high-pressure backwashing interface 15 penetrates the inner secondary lining structure 5 radially, and a valve is provided on the high-pressure backwashing interface 15.

[0031] The inner secondary lining structure 5 is made of permeable concrete. It must be selected according to the specific project's structural load-bearing design requirements and impermeability standards, using permeable concrete of the corresponding strength grade and matching the target permeability coefficient. Based on capillary pores 6, the porosity of the inner secondary lining structure 5 is 10%~20%. The specific calculation and measurement methods for the capillary pores 6 mainly include two methods: theoretical mix proportion calculation and actual measurement. The theoretical mix proportion calculation method: Before material mixing, the porosity is calculated based on the volume relationship of the constituent materials. Porosity = [1-( V g + V c + V w ) / V ]×100%, V The total volume of the permeable concrete. V g , V c , V w These represent the actual volume of aggregates, cementitious materials such as cement, and water in the mix proportion, respectively. Actual measurement method: Referring to relevant testing standards for permeable concrete such as ASTM C1688, the actual density of freshly mixed permeable concrete is measured and compared with its theoretical density in a fully compacted state. The formula is: Porosity = [1 - (Measured density / Theoretical density)] × 100%. This porosity not only ensures that high-pressure water can slowly seep out and fill the capillary pores 6, forming a continuous liquid water film on the inner wall of the inner secondary lining structure 5, but also resists structural expansion and cracking caused by water pressure generated by pore permeation.

[0032] The capillary pores 6 within the inner secondary lining structure 5 are filled by high-pressure water supplied from inside the water conveyance tunnel, forming a continuous liquid water film under the pressure of the internal water. The liquid water film utilizes surface tension to construct a hydraulic barrier that resists air pressure, blocking the escaping gas entering the circumferential gas collecting interlayer 3. The gas accumulated in the circumferential gas collecting interlayer 3 and the gas extraction pipe 7 are transported to the gas exhaust pipe 8 for centralized discharge, thereby achieving dynamic coordinated protection through external blocking, middle diversion, and internal water sealing.

[0033] An isolation plate 10 is laid between the outer primary support lining structure 2 and the inner secondary lining structure 5 to prevent the concrete from squeezing and intruding during the pouring of the inner secondary lining structure 5, so as to ensure that the circumferential air collection layer 3 is not blocked by concrete. The isolation plate 10 is a perforated boss isolation plate. The isolation plate 10 is located in the circumferential gas collection layer 3 as a supporting skeleton. The isolation plate 10 includes a substrate and bosses provided on the substrate. One side of the substrate is in contact with the outer wall of the inner secondary lining structure 5. The substrate is provided with vent holes, allowing the accumulated gas to pass through the substrate 10 and contact the liquid water film on the surface of the inner secondary lining structure 5, so that the gas accumulated in the circumferential gas collection layer 3 can pass through smoothly. The bosses are in contact with the inner wall of the outer primary support lining structure 2.

[0034] A multi-field coupling monitoring and early warning system is installed in the circumferential gas collection layer 3. The multi-field coupling monitoring and early warning system includes a strain sensor 11 attached to the inner surface of the outer primary support lining structure 2, a gas pressure concentration sensor 12 arranged on the outer side of the substrate of the isolation plate 10, a humidity sensor 13 attached to the outer surface of the inner secondary lining structure 5, and a gas flow sensor 14 installed in the gas exhaust straight pipe 8.

[0035] Given the upward migration characteristics of gas, the gas pressure concentration sensor 12 is installed in the arch top and the two sides of the arch waist area within the circumferential gas collection layer 3; given that the water pressure is the lowest in the arch top, the humidity sensor 13 is installed on the outer side of the arch top and the two sides of the arch waist of the inner secondary lining structure 5; considering the high ground stress and fault slip characteristics, the strain sensor 11 should be installed in accordance with the fault sliding surface on both sides of the outer primary support lining structure 2 and the number of sensors should be increased locally and asymmetrically.

[0036] A construction and operation method for a water conveyance tunnel lining structure with hydraulic self-sealing function in high-gas coal-outburst strata includes the following steps: S1: After the working face of the water conveyance tunnel is excavated, a pressure relief hole is drilled into the gas-bearing coal seam 1 and a gas drainage pipe 7 wrapped with an anti-clogging filter screen is driven in, and the hole is sealed at the opening section of the pressure relief hole. S2: The excavation outline of the water conveyance tunnel is initially closed, and the tail end of the gas drainage pipe 7 is protected by a casing so that it penetrates the initial support concrete attached to the inner wall of the water conveyance tunnel and leaves an exposed joint section of 100 mm to 150 mm on the inner side of the water conveyance tunnel. High impermeable concrete is initially sprayed onto the initial support concrete to form the outer initial support lining structure 2. S3: Lay an isolation plate 10 along the inner surface of the outer primary support lining structure 2, use the boss to open and forcibly retain the space of the circumferential gas collection interlayer 3, set a strain sensor 11 on the inner surface of the outer primary support lining structure 2, set a gas pressure concentration sensor 12 on the outer side of the substrate of the isolation plate 10, and lead out the cables of the strain sensor 11 and the gas pressure concentration sensor 12. S4: Tie the steel reinforcement skeleton used to prepare the inner secondary lining structure 5, tie the humidity sensor 13 to the steel reinforcement on the side of the skeleton near the isolation plate 10, lead out the cable of the humidity sensor 13, and pour permeable concrete on the skeleton using short-time low-frequency vibration process to form the circumferential air collection layer 3 and the inner secondary lining structure 5, and complete the construction. S5: When the water conveyance tunnel is put into operation, the cables of strain sensor 11, air pressure concentration sensor 12, and humidity sensor 13 are connected to the corresponding control system, and a stepped slow water filling process is adopted to increase the internal water pressure of the water conveyance tunnel. The stepped slow water filling process is a graded, intermittent water injection method. It is necessary to accurately control the water level rise rate (e.g., each stage is no more than 10m) and set a pressure stabilization time at each stage to observe the structural response. The water filling rate is usually controlled at 5m / h~10m / h. The internal water pressure refers to the hydrostatic pressure of the water body inside the water conveyance tunnel acting on the tunnel wall. When the water pressure gradually rises to the nominal maximum operating water pressure value designed for the water conveyance tunnel project, and the monitoring system does not detect abnormal leakage or structural deformation, the pressure increase and water filling are stopped, and the normal constant pressure water supply operation is entered. The water fills the capillary pores 6, forming a continuous liquid water film on the outer wall of the inner secondary lining structure 5 on the side facing the gas collecting interlayer 3, thus activating the hydraulic sealing barrier. The continuous liquid water film Throughout the entire life cycle of the water conveyance tunnel, a multi-field coupled monitoring and early warning system is used for linkage monitoring. The strain sensor 11 is used to monitor the long-term surrounding rock deformation during the tunnel operation period in real time. The water conveyance tunnel operation period control system compares the seepage water pressure of the air pressure concentration sensor 12 and the humidity sensor 13 in real time. When the air pressure is abnormally high, the suction negative pressure of the tunnel ventilation equipment 9 is increased to ensure the safety of the water conveyance tunnel.

[0037] This invention has a three-level progressive response mechanism: The first stage involves multi-field coupling judgment and active extraction: the control system extracts and compares dynamic data from the gas pressure concentration sensor 12, humidity sensor 13, and gas flow sensor 14 in real time; when the gas pressure in the circumferential gas collection interlayer 3 is detected to be continuously rising and the flow rate in the gas exhaust straight pipe 8 is sharply reduced; or when the gas pressure / water pressure ratio in the interlayer reaches the warning threshold, posing a risk of water film breach, the control system determines that the pipeline is blocked, and the control system automatically links to increase the suction negative pressure of the tunnel ventilation equipment 9 for forced extraction. The first stage is negative pressure extraction; the second stage is structural redundancy diversion: the gas in the blocked area will break through the micro-fractures of the gas-bearing coal seam 1 and seep into the circumferential gas gathering interlayer 3, and be discharged from other unblocked pipelines connecting the circumferential gas gathering interlayer 3; the third stage is active flushing and repair. During the maintenance period, the maintenance personnel can use the reserved high-pressure backflushing interface 15 to connect the circumferential gas gathering interlayer 3 to high-pressure airflow or water flow for reverse pulse purging, which will break up the accumulated coal dust and blow it back to the fissures of the gas-bearing coal seam 1 along the gas discharge pipe 7, restoring the drainage capacity of the pipeline network.

[0038] This invention utilizes three natural physical mechanisms to achieve long-term, zero-energy safety control: First, leveraging the physical property that methane density is less than air, methane is naturally transported into and collected in the methane exhaust pipe by arranging methane drainage pipes on both sides of the water conveyance tunnel. Second, it fully utilizes the inherent high-pressure water potential energy within the water conveyance tunnel during operation, forcing a small amount of transported water to seep into the capillary pores of the secondary lining and form a continuous liquid water film, blocking the escaping methane within the circumferential gas collection interlayer. Third, it utilizes Bernoulli's principle in fluid mechanics, arranging the exhaust end of the methane exhaust pipe in the direction of the wind, and using the stable negative pressure generated at the exhaust pipe opening by the high-speed jet airflow to achieve automatic and continuous extraction and discharge of accumulated methane. This invention eliminates the need for additional high-energy-consuming extraction pumping stations or complex power machinery inside the tunnel, achieving both safety and economy throughout the entire life cycle of high-methane tunnel operation.

Claims

1. A lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function, characterized in that: Based on the radial direction of the water conveyance tunnel, an outer primary support lining structure (2), a circumferential gas gathering interlayer (3), and an inner secondary lining structure (5) are sequentially arranged from the gas-bearing coal seam (1) toward the center of the water conveyance tunnel. A gas drainage main pipe (4) is arranged inside the circumferential gas gathering interlayer (3).

2. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 1, characterized in that: The outer primary support lining structure (2) is set close to the excavation outline of the gas-bearing coal seam (1); The circumferential gas collecting interlayer (3) is disposed between the outer primary support lining structure (2) and the inner secondary lining structure (5); The inner secondary lining structure (5) has capillary pores (6). The gas exhaust main (4) is provided with several radially arranged gas exhaust pipes (7) and longitudinally arranged gas exhaust straight pipes (8).

3. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 2, characterized in that: The gas exhaust pipe (7) is installed through the outer primary support lining structure (2), with its front end inserted into the gas-containing coal seam (1) and its tail end extending into the circumferential gas collection interlayer (3) and converging to the gas exhaust straight pipe (8). The gas exhaust pipe (8) is installed in the circumferential gas collection interlayer (3) at the arch of the water conveyance tunnel, and the exhaust end of the gas exhaust pipe (8) is connected to the downwind port of the tunnel ventilation equipment (9) installed on the inner wall of the inner secondary lining structure (5).

4. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 3, characterized in that: The gas drainage pipe (7) is inserted into the gas-containing coal seam (1) and the outside of the pipe section is wrapped with an anti-clogging filter screen; The gas exhaust manifold (4) is arched upward along the inner wall of the water conveyance tunnel. The lower end of the gas exhaust manifold (4) is closed, and its exhaust port is connected to the gas exhaust straight pipe (8) which is set along the axis of the water conveyance tunnel, so that the axis of the gas exhaust straight pipe (8) is set along the wind direction of the tunnel ventilation equipment (9).

5. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 3, characterized in that: The gas drainage pipes (7) are arranged in a fan-shaped, non-full-section manner, and are respectively located in the arch, waist and side wall areas of the water conveyance tunnel.

6. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 2, characterized in that: The center distance between the tail ends of adjacent gas exhaust pipes (7) connected to the gas exhaust straight pipe (8) is no more than 0.5m; the gas exhaust pipe (4) is provided with a high-pressure backwashing interface (15), which penetrates the inner secondary lining structure (5) radially.

7. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 2, characterized in that: The inner secondary lining structure (5) is made of permeable concrete. The porosity of the inner secondary lining structure (5) is 10%~20% based on capillary pores (6).

8. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 2, characterized in that: An isolation plate (10) is laid between the outer primary support lining structure (2) and the inner secondary lining structure (5). The isolation plate (10) is located inside the circumferential gas collection layer (3). The isolation plate (10) includes a substrate and a boss provided on the substrate. The substrate is provided with air vents.

9. The lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in claim 8, characterized in that: The circumferential gas collection layer (3) is equipped with a multi-field coupling monitoring and early warning system, which includes a strain sensor (11) attached to the inner surface of the outer primary support lining structure (2), a gas pressure concentration sensor (12) arranged on the outer side of the substrate of the isolation plate (10), a humidity sensor (13) attached to the outer surface of the inner secondary lining structure (5), and a gas flow sensor (14) installed in the gas exhaust pipe (8).

10. A method for construction and operation of a lining structure for a water conveyance tunnel in a high-gas coal-outburst stratum with hydraulic self-sealing function as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: After the working face of the water conveyance tunnel is excavated, a pressure relief hole is drilled into the gas-bearing coal seam (1) and a gas drainage pipe (7) is driven in, and the hole is sealed at the opening section of the pressure relief hole. S2: The excavation outline of the water conveyance tunnel is initially closed, and the tail end of the gas drainage pipe (7) is protected by a casing so that it penetrates the initial support concrete attached to the inner wall of the water conveyance tunnel and leaves an exposed joint section on the inner side of the water conveyance tunnel. Initial concrete is sprayed onto the initial support concrete to form an outer initial support lining structure (2). S3: Lay an isolation plate (10) along the inner surface of the outer primary support lining structure (2), set a strain sensor (11) on the inner surface of the outer primary support lining structure (2), set a gas pressure concentration sensor (12) on the outer side of the substrate of the isolation plate (10), and lead out the cables of the strain sensor (11) and the gas pressure concentration sensor (12). S4: Tie the skeleton used to prepare the inner secondary lining structure (5), tie the humidity sensor (13) to the skeleton near the isolation plate (10), lead out the cable of the humidity sensor (13), pour concrete on the skeleton to form the circumferential air collection layer (3) and the inner secondary lining structure (5), and complete the construction. S5: When the water conveyance tunnel is put into operation, the internal water pressure of the water conveyance tunnel is increased by a step-by-step slow water filling process, so that the water fills the capillary pores (6) and forms a continuous liquid water film on the outer wall of the inner secondary lining structure (5), thus activating the hydraulic sealing barrier.

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