An extraction-type construction ventilation system for an extra-long high-gas tunnel

Abstract

The present invention provides an extraction-type construction ventilation system for extra-long high-gas tunnels, which includes a drainage tunnel, an inclined shaft, a left line, a right line, a parallel heading, a main air intake unit, a main air return unit, and a branch ventilation unit; the main air intake unit includes an air intake area, at least three fresh air fans, and at least three air ducts. The air intake area is located at the rear ends of the left line and the parallel heading, and the air intake area is connected to the inclined shaft. The fresh air fans are arranged in the air intake area. The three fresh air fans correspond to the left line, the parallel heading, and the right line respectively. Each fresh air fan sends fresh air to the corresponding excavation face through an air duct; the main air return unit includes an air return area and an exhaust fan. The air return area is located at the rear end of the right line and is connected to the drainage tunnel. The exhaust fan is arranged in the drainage tunnel and exhausts air from the inside to the outside; the branch ventilation unit includes a ventilation area. The ventilation area is located at the respective front ends of the left line, the right line, and the parallel heading. The exhaust fan sucks out the old air in the ventilation area, so that the fresh air enters the ventilation area from the air intake area. The present invention separates the transportation of fresh air and old air, and has high safety.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and particularly to an exhaust-type construction ventilation system for extra-long high-gas tunnels. Background Art

[0002] In the construction of some newly built extra-long double-track (separate construction of two tunnels) + parallel pilot tunnels in recent years, a new type of "phase-type hybrid" ventilation system scheme for extra-long tunnels has been applied. This scheme mainly targets the construction organization mode of extra-long tunnels with separate construction of two tunnels + parallel pilot tunnels. By utilizing the air pressure difference formed by the natural height difference between the inclined shaft and the drainage tunnel of the tunnel, through the setting of the air wall on the right line, the overall intake airway (drainage tunnel) and the return airway (inclined shaft) are formed, so as to achieve the negative-pressure exhaust ventilation mode. During the construction period, the "phase-type" ventilation technology is adopted. Combining the construction state of the parallel pilot tunnel leading the left and right main lines, the overall single-heading ventilation distance is divided into three sections by moving the position of the air wall multiple times, with each section being 2-3 km, realizing the effect of dynamic ventilation management of "long tunnel, short ventilation" for 10 km single-heading tunneling.

[0003] However, this ventilation system scheme is mainly for tunnel construction in an overall work area with a gas-free environment and small air volume requirements. Its fresh air intake is mainly achieved by the suction operation of axial fans configured at each working surface on the air wall in the air chamber. As the tunnel excavation progresses, the air wall in the air chamber needs to be moved forward in stages. Although this reduces the air supply distance of the axial fans to a certain extent, it will increase the distance for fresh air on the right line to enter the intake airway, and at the same time, the intake friction resistance also increases accordingly. This will make it extremely difficult for the axial fans at the air wall in the air chamber to suck air, resulting in difficulties in supplying air to the excavation face, and further leading to insufficient air supply, causing safety problems in tunnel construction. Moreover, in this ventilation system scheme, the fresh air and the stale air are mixed together, making it difficult to distinguish whether the air reaching the excavation face is fresh air, stale air, or a mixture of the two. Therefore, this ventilation system scheme cannot be applied to the construction of gas tunnels or high-gas tunnels. Summary of the Invention

[0004] The object of the present invention is to provide an exhaust-type construction ventilation system for extra-long high-gas tunnels that separates fresh air from stale air and transports them independently, is safe and efficient, and is particularly suitable for gas or high-gas tunnels.

[0005] To achieve the above object, a long-type high-gas tunnel exhaust construction ventilation system provided by the present invention includes a drainage tunnel, an inclined shaft, a left line, a right line and a parallel heading. The left line and the right line are respectively arranged on both sides of the parallel heading. The inclined shaft is arranged on one side of the left line, and the drainage tunnel is arranged on one side of the right line. Excavation faces are respectively arranged in the left line, the right line and the parallel heading. The exhaust construction ventilation system further includes a main air intake unit, a main air return unit and a branch ventilation unit. The main air intake unit is communicated with the main air return unit through the branch ventilation unit; the main air intake unit includes an air intake area, at least three fresh air fans and at least three air ducts. The air intake area is located at the rear ends of the left line and the parallel heading. The air intake area is communicated with the inclined shaft and can expand forward along the construction direction. The fresh air fans are arranged in the air intake area. The three fresh air fans respectively correspond to the left line, the parallel heading and the right line. Each fresh air fan sends fresh air to the corresponding excavation face through an air duct; the main air return unit includes an air return area and an exhaust fan. The air return area is located at the rear end of the right line and is communicated with the drainage tunnel. The air return area can expand forward along the construction direction. The exhaust fan is arranged in the drainage tunnel and exhausts air from the inside to the outside; the branch ventilation unit includes a ventilation area. The ventilation area is located at the front ends of the left line, the right line and the parallel heading. The ventilation area is respectively communicated with the air intake area and the air return area. The exhaust fan exhausts the old air in the ventilation area to the outside, so that the fresh air enters the ventilation area from the air intake area.

[0006] As can be seen from the above solution, by arranging an exhaust fan in the drainage tunnel to exhaust the old air in the tunnel to the outside, the fresh air enters the tunnel from the inclined shaft, and at the same time, the content of gas in the tunnel is reduced, achieving the ventilation effect of tunnel construction, preventing explosion during the tunnel boring construction process, and improving the construction safety; by arranging fresh air fans and air ducts, the fresh air is directly conveyed to each excavation face through the air ducts, facilitating the normal free breathing of construction workers and preventing the occurrence of hypoxia. The present invention is particularly applicable to the construction of gas or high-gas tunnels. The old air in the tunnel contains gas. The present invention uses the exhaust fan to suck away the old air containing gas, so that there is enough fresh air in the fresh air area to ensure that the air intake volume of the fresh air fan meets the design requirements, preventing the increase in the damage rate of the motor operation of the fresh air fan due to insufficient air intake volume, and using the fresh air fan and the air duct to convey fresh air. On the one hand, it can reduce the content of gas in the tunnel, and on the other hand, it can also ensure that the fresh air will not be mixed with the old air during the conveying process, preventing the fresh air from being polluted by the gas of the old air, which is beneficial to ensuring the supply of fresh air in the area near the excavation face and improving the safety and efficiency of tunnel construction.

[0007] A further solution is that a partition part is provided between the inclined shaft and the left line. The partition part divides the air flow of the inclined shaft into a first flow path and a second flow path. The first flow path is communicated with the rear end of the left line, and the second flow path is communicated with the front end of the left line; a movable air door for adjusting the air flow volume at the front and rear ends of the left line is arranged in the left line. The movable air door is located on one side of the partition part.

[0008] A further solution is that a first cross passage and a second cross passage are provided between the inclined shaft and the drainage tunnel. The first cross passage is respectively connected to the first flow channel, the left line, the right line and the pilot tunnel, and the second cross passage is respectively connected to the second flow channel, the left line, the right line and the pilot tunnel. A first air wall is provided between the first cross passage and the right line, and a second air wall is provided between the first cross passage and the pilot tunnel. An air intake area is formed among the first cross passage, the first air wall, the second air wall and the movable air door.

[0009] As can be seen from the above solution, by providing the first flow channel and the second flow channel, the fresh air is divided into two branches. The fresh air of one branch is directly conveyed to an excavation face of the left line closest to the inclined shaft, and the fresh air of the other branch converges in the air intake area, which facilitates the fresh air fan to shoot the fresh air to other excavation faces of the left line, the excavation face of the pilot tunnel and each excavation face of the right line, is conducive to reasonably adjusting the intake volume of the fresh air, balancing the air suction volume of each fresh air fan, and ensuring that there is sufficient fresh air at each excavation face.

[0010] A further solution is that a plurality of right cross passages are provided between the pilot tunnel and the right line. The two ends of the right cross passage are respectively connected to the pilot tunnel and the right line, and the air duct located in the pilot tunnel passes through the right cross passage and extends to the excavation face of the right line. A plurality of left cross passages are provided between the pilot tunnel and the left line. The two ends of the left cross passage are respectively connected to the pilot tunnel and the left line, and the air duct located in the pilot tunnel passes through the left cross passage and extends to the excavation face of the left line. The front ends of the left line, the right line, the pilot tunnel, the right cross passage and the left cross passage form a ventilation area.

[0011] As can be seen from the above solution, by providing the left cross passage and the right cross passage, on the one hand, it is conducive to accelerating the tunnel construction progress, and on the other hand, it is convenient for the laying of the air duct.

[0012] A further solution is that a Y-shaped exhaust channel is connected to the end of the drainage tunnel far from the right line, and an exhaust fan is arranged at the first end of the Y-shaped exhaust channel. A standby exhaust fan is also arranged in the return air area, and the standby exhaust fan is arranged at the second end of the Y-shaped exhaust channel.

[0013] As can be seen from the above solution, when the exhaust fan is under maintenance or fails, starting the standby exhaust fan is conducive to ensuring the normal and continuous operation of the tunnel construction ventilation system.

[0014] A further solution is that a plurality of left-line excavation faces are arranged in the left line, a plurality of right-line excavation faces are arranged in the right line, and a pilot-tunnel excavation face is arranged in the pilot tunnel. In the construction direction, the pilot-tunnel excavation face is ahead of all the left-line excavation faces and the right-line excavation faces. The fresh air fans correspond to the left-line excavation faces, the pilot-tunnel excavation face and the right-line excavation faces one by one, and the number of the air ducts is equal to the number of the fresh air fans.

[0015] A further solution is that when the return air area expands forward along the construction direction, a first air baffle and a plurality of second air baffles are arranged in the return air area. The first air baffle is blocked at the rear end of the right line, and the second air baffle is blocked between the air intake area and the return air area.

[0016] As can be seen from the above solution, by setting the first windbreak wall and the second windbreak wall, it is beneficial to adjust the extension direction of the return air area, so as to suck away the old air in the construction area at the front end of the tunnel to the greatest extent and avoid the fresh air in the fresh air area being sucked away before reaching the construction area.

[0017] A further solution is that when the air inlet area expands forward along the construction direction, both the fresh air fan and the air duct move forward following the air inlet area.

[0018] As can be seen from the above solution, by setting both the fresh air fan and the air duct to move forward following the air inlet area, it is beneficial to reduce the length of the air duct and improve the conveying speed of the fresh air. Description of the Drawings

[0019] Figure 1 is the structural diagram of the embodiment of the present invention.

[0020] Figure 2 is the enlarged view of the air inlet area and the return air area in the embodiment of the present invention.

[0021] Figure 3 is the structural diagram after the first forward expansion of the embodiment of the present invention.

[0022] Figure 4 is the enlarged view of the air inlet area and the return air area after the first forward expansion in the embodiment of the present invention.

[0023] Figure 5 is the structural diagram after the second forward expansion of the embodiment of the present invention.

[0024] The present invention will be further described below with reference to the drawings and embodiments. Detailed Embodiments

[0025] Referring to Figure 1 and Figure 2 , the exhaust type construction ventilation system provided in this embodiment is particularly applicable to the construction of extra-long high-gas tunnels. The exhaust type construction ventilation system includes a drainage tunnel 1, an inclined shaft 2, a left line 3, a right line 4 and a parallel heading 5. The left line 3 and the right line 4 are arranged in parallel on both sides of the parallel heading 5. The drainage tunnel 1 is located on one side of the right line 4 and is connected to the right line 4. The inclined shaft 2 is located on one side of the left line 3 and is connected to the left line 3. A plurality of left cross passages 6 are provided between the left line 3 and the parallel heading 5, and the plurality of left cross passages 6 are arranged along the construction direction. The left line 3 is connected to the parallel heading 5 through the left cross passages 6. A plurality of right cross passages 7 are provided between the right line 4 and the parallel heading 5, and the plurality of right cross passages 7 are arranged along the construction direction. The right line 4 is connected to the parallel heading 5 through the right cross passages 7.

[0026] An excavation face is respectively arranged in the left line 3, the right line 4 and the parallel heading 5. And in the construction direction, the excavation face of the parallel heading 5 is ahead of the excavation face of the left line 3 and also ahead of the excavation face of the right line 4. In order to improve the construction efficiency, multiple excavation faces are arranged in both the left line 3 and the right line 4, and multiple excavation faces are simultaneously tunneling and constructing. In Figure 1 and Figure 2 the left line 3 is provided with two left-line excavation faces 31, and the right line 4 is provided with two right-line excavation faces 41.

[0027] The extraction-type construction ventilation system further includes a main air inlet unit, a main air return unit and a branch ventilation unit. The main air inlet unit is communicated with the main air return unit through the branch ventilation unit to realize the function of ventilation and air change in the tunnel.

[0028] The main air inlet unit includes an air inlet area 8, five fresh air fans 81 and five air ducts 82. The five fresh air fans 81 convey fresh air forward through the corresponding air ducts 82. The air inlet area 8 is located at the rear ends of the left line 3 and the parallel heading 5. The air inlet area 8 is communicated with the inclined shaft 2, and the air inlet area 8 can extend forward along the construction direction. The fresh air fans 81 are arranged in the air inlet area 8. The fresh air fans 81 are arranged in one-to-one correspondence with each excavation face. The number of the fresh air fans 81 is equal to the number of the air ducts 82. Each fresh air fan 81 conveys fresh air to the corresponding excavation face through an independent air duct 82, which is convenient for the independent tunneling construction of each excavation face in the tunnel.

[0029] In Figure 2 a triangular partition 21 is arranged between the inclined shaft 2 and the left line 3. The partition 21 divides the passage of the inclined shaft 2 into a first flow channel 22 and a second flow channel 23. The first flow channel 22 is communicated with the rear end of the left line 3, and the second flow channel 23 is communicated with the front end of the left line 3. A movable air door 32 is arranged between the front end and the rear end of the left line 3. The movable air door 32 is located on one side of the partition 21. The movable air door 32 is used to adjust the air flow rate between the front end and the rear end of the left line 3. Since the left line 3 is directly communicated with the second flow channel 23 of the inclined shaft 2, a fresh air fan 81 is arranged between the second flow channel 23 and the left line 3. The fresh air fan 81 conveys fresh air into the left line 3 through the air duct 82 to the left-line excavation face 31 closest to the inclined shaft 2. The air duct 82 is preferably arranged along one side of the left line 3, and the direction is that the stale air is discharged from the other side of the left line 3, so that the fresh air and the stale air have their own independent routes respectively, which is beneficial to ensuring the smooth flow of the fresh air and the stale air.

[0030] A first cross passage 11 and a second cross passage 12 are provided between the inclined shaft 2 and the drainage tunnel 1. The first cross passage 11 is respectively connected to the first flow passage 22, the left line 3, the pilot tunnel 5 and the right line 4, and the second cross passage 12 is respectively connected to the second flow passage 23, the left line 3, the pilot tunnel 5 and the right line 4. A first air wall 111 is sealingly provided between the first cross passage 11 and the right line 4 for cutting off the air flow between the first cross passage 11 and the right line 4, so that the fresh air converges on one side of the first air wall 111 facing the pilot tunnel 5. A second air wall 112 is sealingly provided between the first cross passage 11 and the pilot tunnel 5 for cutting off the air flow between the first cross passage 11 and the pilot tunnel 5, so that the fresh air converges on one side of the second air wall 112 facing the first cross passage 11. In this embodiment, the above-mentioned air inlet area 8 is formed among the first cross passage 11, the first air wall 111, the second air wall 112 and the movable air door 32.

[0031] Generally, three fresh air fans 81 are arranged in the pilot tunnel 5. The three fresh air fans 81 are all located on one side of the second air wall 112 facing the air inlet area 8. The air duct 82 passes through the second air wall 112 and extends along the pilot tunnel 5 towards the pilot tunnel excavation face 51. The air duct 82 can also extend towards the left line excavation face 31 and the right line excavation face 41 respectively through the left cross passage 6 and the right cross passage 7. Due to the limited space of the pilot tunnel 5, it is impossible to accommodate all the fresh air fans 81 and all the air ducts 82. For a right line excavation face 41 closest to the air inlet area 8, a fresh air fan 81 can be arranged in the first cross passage 11, and the air duct 82 extending through the corner extends to the right line excavation face 41; for a left line excavation face 31 closest to the air inlet area 8, since the inclined shaft 2 is directly connected to the left line 3 through the second flow passage 23, a fresh air fan 81 can be directly arranged in the left line 3, and the air duct 82 extending in a straight line extends to the left line excavation face 31.

[0032] The main return air unit includes a return air area 9, an exhaust fan 91 and a standby exhaust fan 92. The return air area 9 is located at the rear end of the right line 4. The return air area 9 is connected to the drainage tunnel 1, and the return air area 9 can extend forward along the construction direction. One end of the drainage tunnel 1 is connected to the right line 4, and the other end of the drainage tunnel 1 is connected with a "Y"-shaped exhaust passage. The exhaust fan 91 is arranged at the first end of the "Y"-shaped exhaust passage, and the standby exhaust fan 92 is arranged at the second end of the "Y"-shaped exhaust passage. Both the exhaust fan 91 and the standby exhaust fan 92 can exhaust air from the inside to the outside, so as to form a negative pressure environment in the tunnel, and the fresh air automatically enters the tunnel from the inclined shaft 2 under the action of pressure. Compared with the prior art, the exhaust fans added in this embodiment ensure the fresh air volume in the air inlet area. The return air area 9 is connected to the excavation face in the right line 4 closest to the drainage tunnel 1 for exhausting the old air near the excavation face; at the same time, the return air area 9 is also connected to the second cross passage 12, so that the old air in the pilot tunnel 5 and the left line 3 can flow towards the return air area 9.

[0033] The branch ventilation unit includes a ventilation area 10, which is located at the front ends of the left line 3, the right line 4, and the parallel heading 5. The ventilation area 10 is respectively connected to the air intake area 8 and the return air area 9. The exhaust fan 91 extracts the old air containing gas in the ventilation area 10 outwards through the return air area 9, enabling fresh air to enter the ventilation area 10 from the air intake area 8. The front ends of the left line 3, the right line 4, the front end of the parallel heading 5, the left cross passage 6, and the right cross passage 7 form the ventilation area 10, and the old air in the ventilation area 10 flows along a preset direction.

[0034] See Figure 3 and Figure 4 , as the tunnel is constructed in phases, both the air intake area 8 and the return air area 9 extend forward along the construction direction, and the ventilation area 10 gradually moves backward along the construction direction. Correspondingly, the fresh air fan 81 and the air duct 82 move forward following the extension of the air intake area 8.

[0035] When the air intake area 8 extends forward, a third windbreak wall 95 is sealingly arranged between the first flow channel 22 and the left line 3, so that fresh air only enters the tunnel from the second flow channel 23. At the same time, the movable air door 32 is closed, and the second wind wall 112 between the first cross passage 11 and the second cross passage 12 and the first wind wall 111 located in the first cross passage 11 are retained, so that fresh air can only flow forward along the construction direction. To prevent the fresh air in the air intake area 8 from directly flowing towards the return air area 9. A first windbreak wall 93 and a plurality of second windbreak walls 94 are arranged in the return air area 9. The first windbreak wall 93 is blocked at the rear end of the right line 4, and attention is paid to keeping the connection between the return air area 9 and the drainage tunnel 1. The second windbreak walls 94 are blocked in the right cross passage 7 to cut off the air flow between the air intake area 8 and the return air area 9. At this time, the fresh air in the air intake area can only flow forward along the left line 3 and the parallel heading 5. A second wind wall 112 is arranged in the middle of the parallel heading 5, and this second wind wall is located at the front end of the fresh air fan 81 and is used to block the free flow of fresh air to the ventilation area, and then the fresh air is conveyed to the corresponding excavation face through the fresh air fan 81 located on one side of this second wind wall 112 and the air duct 82 passing through this second wind wall 112. The left line 3 is provided with three left line excavation faces 31. Except for the excavation face closest to the air intake area 8, which is supplied with fresh air through the fresh air fan 81 arranged in the left line 3, the other two excavation faces in the left line 3 are supplied with fresh air through the fresh air fan 81 arranged in the middle of the parallel heading 5. Four fresh air fans 81 are arranged in the middle of the parallel heading 5, two of which are used to supply fresh air to the left line excavation faces 31, one of which is used to supply fresh air to the parallel heading excavation face 51, and the other is used to supply fresh air to the right line excavation face. The right line 4 is provided with two right line excavation faces, and the right line excavation face closest to the return air area 9 is supplied with fresh air through the fresh air fan 81 on one side of the closest second windbreak wall 94.

[0036] There is at least one left crossheading 6 for air return between the air intake area 8 and the ventilation area 10, and at least one right crossheading 7 for air return between the air return area 9 and the ventilation area 10 to ensure the smooth progress of air return and achieve the purpose of ventilation and air change.

[0037] See Figure 5 , after the construction of one stage is completed, the exhaust-type construction ventilation system can be extended forward for the second time until the construction of the whole-line tunnel is completed. During the construction process of each stage, the number of excavation faces of the left line 3 and the right line 4 can be adjusted according to actual requirements. The number of fresh air blowers 81 is adjusted according to the number of excavation faces.

[0038] In summary, in the present invention, an exhaust fan is arranged in the drainage tunnel to extract the old air in the tunnel outward, so that fresh air enters the tunnel from the inclined shaft. At the same time, the content of gas in the tunnel is reduced, the ventilation effect of tunnel construction is achieved, explosion during the tunnel boring construction is prevented, and the construction safety is improved; by arranging fresh air blowers and air ducts, fresh air is directly conveyed to each excavation face through the air ducts, which is convenient for the normal free breathing of construction workers and prevents the occurrence of hypoxia. The present invention is particularly suitable for the construction of gas or high-gas tunnels. The old air in the tunnel contains gas. The present invention uses the exhaust fan to suck away the old air containing gas, so that there is enough fresh air in the fresh air area to ensure that the air intake volume of the fresh air blower meets the design requirements, prevent the increase of the damage rate of the motor of the fresh air blower due to insufficient air intake volume, and use the fresh air blower and the air duct to convey fresh air. On the one hand, it can reduce the content of gas in the tunnel, and on the other hand, it can ensure that the fresh air will not be mixed with the old air during the conveying process, prevent the fresh air from being polluted by the gas of the old air, and is conducive to ensuring the supply of fresh air in the area near the excavation face, and is conducive to improving the safety and efficiency of tunnel construction.

[0039] Finally, it should be emphasized that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An extraction-type construction ventilation system for an extra-long high-gas tunnel, comprising a drainage tunnel, an inclined shaft, a left line, a right line and a parallel heading. The left line and the right line are respectively arranged on both sides of the parallel heading. The inclined shaft is arranged on one side of the left line, and the drainage tunnel is arranged on one side of the right line. Excavation faces are respectively arranged in the left line, the right line and the parallel heading. It is characterized in that: The extraction-type construction ventilation system further comprises a main air inlet unit, a main air return unit and a branch ventilation unit. The main air inlet unit is communicated with the main air return unit through the branch ventilation unit; The main air inlet unit comprises an air inlet area, at least three fresh air fans and at least three air ducts. The air inlet area is located at the rear ends of the left line and the parallel heading and is communicated with the inclined shaft. The air inlet area can extend forward along the construction direction. The fresh air fans are arranged in the air inlet area. The three fresh air fans respectively correspond to the left line, the parallel heading and the right line. Each fresh air fan sends fresh air to the corresponding excavation face through the air duct; The main air return unit comprises an air return area and an exhaust fan. The air return area is located at the rear end of the right line and is communicated with the drainage tunnel. The air return area can extend forward along the construction direction. The exhaust fan is arranged in the drainage tunnel and exhausts air from the inside to the outside; The branch ventilation unit comprises a ventilation area. The ventilation area is located at the front ends of the left line, the right line and the parallel heading. The ventilation area is respectively communicated with the air inlet area and the air return area. The exhaust fan extracts the old air in the ventilation area to the outside, so that the fresh air enters the ventilation area from the air inlet area; A partition part is arranged between the inclined shaft and the left line. The partition part divides the inclined shaft into a first flow channel and a second flow channel. The first flow channel is communicated with the rear end of the left line, and the second flow channel is communicated with the front end of the left line; An adjustable air door for adjusting the air flow rate at the front and rear ends of the left line is arranged in the left line. The adjustable air door is located on one side of the partition part; A first cross passage and a second cross passage are arranged between the inclined shaft and the drainage tunnel. The first cross passage is respectively communicated with the first flow channel, the left line, the right line and the parallel heading. The second cross passage is respectively communicated with the second flow channel, the left line, the right line and the parallel heading; A first air wall is arranged between the first cross passage and the right line, and a second air wall is arranged between the first cross passage and the parallel heading. The first cross passage, the first air wall, the second air wall and the adjustable air door form the air inlet area; A plurality of right cross passages are arranged between the parallel heading and the right line. Both ends of the right cross passage are respectively communicated with the parallel heading and the right line. The air duct located in the parallel heading passes through the right cross passage and extends to the excavation face of the right line; A plurality of left cross passages are arranged between the parallel heading and the left line. Both ends of the left cross passage are respectively communicated with the parallel heading and the left line. The air duct located in the parallel heading passes through the left cross passage and extends to the excavation face of the left line; The front ends of the left line, the right line, the parallel heading, the right cross passage and the left cross passage form the ventilation area.

2. The exhaust-type construction ventilation system for a long and extra-long high-gas tunnel according to claim 1, wherein: A Y-shaped exhaust passage is communicatively arranged at one end of the drainage tunnel away from the right line, and the exhaust fan is arranged at the first end of the Y-shaped exhaust passage; A standby exhaust fan is further arranged in the return air area, and the standby exhaust fan is arranged at the second end of the Y-shaped exhaust passage.

3. The exhaust-type construction ventilation system for a long and extra-long high-gas tunnel according to claim 1 or 2, wherein: A plurality of left-line excavation faces are arranged in the left line, a plurality of right-line excavation faces are arranged in the right line, and a pilot tunnel excavation face is arranged in the pilot tunnel. In the construction direction, the pilot tunnel excavation face is ahead of all the left-line excavation faces and the right-line excavation faces; The fresh air fans correspond to the left-line excavation faces, the pilot tunnel excavation face and the right-line excavation faces one by one, and the number of the air ducts is equal to the number of the fresh air fans.

4. The exhaust-type construction ventilation system for a long and extra-long high-gas tunnel according to claim 1 or 2, wherein: When the return air area expands forward along the construction direction, a first windbreak wall and a plurality of second windbreak walls are arranged in the return air area. The first windbreak wall is blocked at the rear end of the right line, and the second windbreak walls are blocked between the air inlet area and the return air area.

5. The exhaust-type construction ventilation system for a long and extra-long high-gas tunnel according to claim 1 or 2, wherein: When the air inlet area expands forward along the construction direction, the fresh air fans and the air ducts all move forward following the air inlet area.

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