A high-altitude construction tunnel pressurization and oxygenation ventilation system and method

Abstract

The application discloses a kind of for high altitude construction tunnel pressurization oxygenation ventilation system and method, including hole mouth pressurization chamber, automatic air door, hard air pipe and exhaust pipe, wherein, hole mouth pressurization chamber is set to tunnel hole mouth, it is a closed space, front end is connected with tunnel, and is communicated with tunnel hole inside;Right side of pressurization chamber near rear end extends right, forms right channel;Its left side extends left, forms left channel;Two air doors are spaced apart in right channel and left channel, and in each channel, two air doors cannot be opened or closed simultaneously;Automatic air door, set in tunnel hole, the space of its rear end is communicated with pressurization chamber;Work space is communicated with air supply pipe;Exhaust pipe is used to discharge excess gas in pressurization chamber to outdoor;The pressure difference in pressurization chamber and work space is kept in set range.This system realizes gradient pressure distribution inside tunnel by establishing hole mouth pressurization chamber in tunnel hole and linkage with air door in tunnel.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tunnel construction, and particularly relates to a pressurization and oxygenation ventilation system and method for high-altitude construction tunnel. BACKGROUND

[0002] The unique low pressure, low temperature, and low oxygen concentration of the natural environment of high-altitude construction tunnel brings more severe challenges to the construction of the tunnel. In particular, the problem of oxygen deficiency. Although the oxygen volume concentration is the same at different altitudes, the oxygen partial pressure decreases with the increase of altitude, which may lead to insufficient oxygen supply for construction personnel. Solving the problem of oxygen deficiency by pressurization is a common means.

[0003] At present, the commonly used methods are as follows, one is to realize local pressurization of the front cavity of the tunnel face by cooperating the pressurization power system, the pressure regulating system and the sealing system in the tunnel. However, this method is not convenient for popularization and application due to the high cost of single pressurization power system and certain safety risks. The second is to divide the tunnel into a wind supply area and a pressurization area, and the outlet of the fan in the wind supply area delivers air flow to the inlet of the fan in the pressurization area through the air pipe, so as to solve the problem of insufficient ventilation distance by the way of fan relay. However, this method still cannot solve the problem of low pressure of the tunnel face. SUMMARY

[0004] The purpose of the present application is to provide a pressurization and oxygenation ventilation system and method for high-altitude construction tunnel, which realizes the gradient pressure distribution in the tunnel by setting a pressurization chamber at the tunnel portal and linking with the tunnel air door.

[0005] The present application adopts the following technical scheme: a pressurization and oxygenation ventilation system for high-altitude construction tunnel, comprising a portal pressurization chamber, an automatic air door, a hard air pipe and an exhaust pipe, wherein:

[0006] The portal pressurization chamber is arranged at the tunnel portal and is a closed space, the front end of which is connected with the tunnel and communicates with the inside of the tunnel portal; the width of the portal pressurization chamber from left to right is greater than the left-right span of the tunnel; the pressure in the portal pressurization chamber is maintained at a set value;

[0007] The right side of the pressurization chamber near the rear end extends to the right to form a right channel, and the left side of the pressurization chamber extends to the left to form a left channel; two air doors are arranged in the right channel and the left channel at intervals from left to right, and in each channel, the two air doors cannot be opened or closed at the same time;

[0008] The automatic air door is arranged in the tunnel portal and encloses a closed working space with the tunnel face at the front end; the space at the rear end of the automatic air door communicates with the pressurization chamber; an automatic pressure relief multi-leaf air window is arranged at the upper part of the automatic air door; a supply air pipe is connected to the working space, and the supply air pipe continuously supplies air to the working space to maintain a high pressure in the working space; when the pressure value is greater than the set pressure, the gas in the working space is discharged into the pressurization chamber through the air window;

[0009] An exhaust pipe, a front section of which is located in the portal plenum, and a rear end of which penetrates through a rear side wall of the portal plenum and is located outdoors, is used to exhaust excess gas in the portal plenum to the outdoors, so as to maintain a pressure difference between the portal plenum and the working space within a set range.

[0010] Further, a first drainage ditch is excavated on the left or right side of the tunnel, and the first drainage ditch is excavated in the same direction as the tunnel; a first sump is excavated on the first drainage ditch in the working space, and is close to the automatic air door; the depth of the first sump is lower than the lower end of the automatic air door.

[0011] A second drainage ditch is excavated in the portal plenum on the side where the first drainage ditch is located; a front end of the second drainage ditch is connected to the bottom of the first sump through a first communication pipe; the first communication pipe includes a vertical section connected to the second drainage ditch and a horizontal section connected to the first sump, and the horizontal section is below the ground level.

[0012] A rear end of the second drainage ditch is connected to the outside of the portal plenum through a second communication pipe.

[0013] Further, a second sump is excavated in the portal plenum on the side wall; the second sump is used to receive sewage discharged by the second drainage ditch; the bottom of the second sump is connected to the horizontal section of the second communication pipe; the horizontal section is connected to a vertical section; the horizontal section is below the side wall of the portal plenum and crosses the side wall; the vertical section is vertically upward, and a lower end of the vertical section is connected to an outlet of the horizontal section, and an upper end of the vertical section is used to connect a sewage receiving device.

[0014] Further, the height of the first communication pipe is greater than the water column height of the pressure difference on both sides of the automatic air door in the tunnel, and the height of the second communication pipe is greater than the water column height of the pressure difference on both sides of the side wall of the portal plenum.

[0015] Further, a rotary slagging skip is arranged on the side wall at the rear end of the portal plenum; the rotary slagging skip includes a cylindrical shell which is embedded in the side wall and is enclosed by a plurality of arc-shaped plates connected end to end; both ends of the cylindrical shell are closed by circular end plates; an opening is formed in the cylindrical shell; a rotating shaft is coaxially arranged at the central axis of the cylindrical shell, and both ends of the rotating shaft penetrate through the circular end plates; a plurality of partition plates are arranged on the rotating shaft and are spaced apart around the rotating shaft; the length of each partition plate is in the same direction as the rotating shaft, and the width of each partition plate extends to the inner wall of the cylindrical shell; independent spaces are formed between two adjacent partition plates around the cylindrical shell, and are used to receive and discharge slag from the tunnel to the outside of the portal plenum.

[0016] Further, the air supply pipe comprises a hard air pipe, a front end of the hard air pipe passes through the hole pressure chamber and extends through the automatic air door, at the front end of the hard air pipe and in the working space, a soft air pipe is connected in an axial direction; a rear end of the hard air pipe passes through a rear side wall of the hole pressure chamber and is located outdoors.

[0017] Further, each air door in the right channel and the left channel and the automatic air door comprise a left sealing plate, a right sealing plate, an upper sealing plate and a pair of door plates, the left sealing plate, the pair of door plates and the right sealing plate are vertically arranged and arranged in parallel from left to right; the upper sealing plate is connected to upper ends of the left sealing plate, the pair of door plates and the right sealing plate, an automatic pressure relief multi-leaf air window is formed in the upper sealing plate; a human passage door plate is formed in a lower left end of the pair of door plates.

[0018] The application further discloses a ventilation method of the ventilation system for the high-altitude construction tunnel pressure boosting and oxygen boosting, and the ventilation method comprises the following steps:

[0019] Step one, a hole pressure chamber is arranged, a pressure value is maintained in the hole pressure chamber, an air supply pipe continuously supplies air to the working space to maintain the pressure near the working face; when the pressure near the working face is too large, the automatic pressure relief multi-leaf air window of the automatic air door is opened to discharge the excess gas into the hole pressure chamber; when the pressure in the hole pressure chamber and the pressure value between the hole pressure chamber and the working space are too large, an air exhaust pipe discharges the excess gas in the hole pressure chamber to the outdoors;

[0020] Step two, the waste water in the working face construction process is discharged into the first drainage ditch, sequentially flows into the first water collecting pit, the waste water in the first water collecting pit flows into the second drainage ditch through the first connecting pipe, and then flows into the second water collecting pit, the waste water in the second water collecting pit is discharged to the outdoors through the second connecting pipe, and the pressure relief drainage is completed;

[0021] Step three, the soil in the working face construction process is transported into the hole pressure chamber and is transported out through the rotary discharge skip.

[0022] Step four, when a vehicle passes through the air doors on the outer sides of the left channel and the right channel, the automatic pressure relief multi-leaf air windows of the outer side air doors are opened, the outer side air doors are opened when the pressure inside and outside the outer side air doors is balanced, the vehicle passes through the outer side air doors, the two outer side air doors are closed, the automatic pressure relief multi-leaf air windows of the inner side air doors are opened, and the inner side air doors are opened when the pressure inside and outside the inner side air doors is balanced, the vehicle enters the hole pressure chamber, and the inner side air doors are closed.

[0023] When the vehicle passes through the automatic air door, the automatic pressure relief multi-leaf air window of the automatic air door is opened to discharge the gas in the working space, and the automatic air door is opened when the air pressure before and after the automatic air door is balanced.

[0024] The beneficial effects of the present application are: 1. By setting the tunnel opening plenum and automatic air door in the tunnel, the air pressure of the working face is maintained near the design requirement, without the need for a separate oxygen supply system, and the oxygen partial pressure is increased in a pressurized manner to meet the oxygen supply; the internal gradient pressure distribution of the tunnel is realized by relying on the exhaust pipe and the automatic air door in the tunnel, avoiding the phenomenon of air door damage caused by excessive pressure difference, and in addition, the effect of reducing the exhaust air speed is achieved. 2. By setting up a sump and a communication pipe for drainage, the problem of pressure relief caused by drainage during the pressurization process is solved, thereby maintaining the stability of the internal air pressure near the working face. 3. The rotary slagging skip is embedded in the side wall, and after the excavated rock and soil is sent to the tunnel opening plenum, it is sent to the outside through the rotary slagging skip, and the internal pressure remains stable during the process, and the entire system maintains a stable working state. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a tunnel pressurization and oxygen enrichment ventilation system for high-altitude construction;

[0026] Figure 2 It is a structural schematic diagram of a drainage ditch;

[0027] Figure 2 2a in the figure is an enlarged view of C;

[0028] Figure 2 2b in the figure is a D-D cross-sectional schematic diagram;

[0029] Figure 3 It is a structural schematic diagram of a rotary slagging skip;

[0030] Figure 3 3a in the figure is a structural schematic diagram of a cylindrical shell;

[0031] Figure 3 3b in the figure is an E-E cross-sectional schematic diagram;

[0032] Figure 4 It is a schematic diagram of a tunnel opening exhaust pipe;

[0033] Figure 5 It is a structural schematic diagram of an automatic air door;

[0034] Among them: 1. Blower; 2. Hard air duct; 3. Soft air duct; 4. Differential pressure sensor; 5. Pressure sensor; 6. First infrared laser sensor; 7. Second infrared laser sensor; 8. Automatic damper in the tunnel; 9. Exhaust duct; 10. Rotating slag dump bucket; 11. Automatic damper at the first entrance; 12. Automatic damper at the second entrance; 13. Automatic damper at the third entrance; 14. Automatic damper at the fourth entrance; 15. Portal booster chamber; 16. Vehicle; 17. Bypass pipe; 18. Bypass valve; 19. Drain ditch; 20. Sump; 21. Connecting pipe; 22. Round end plate; 23. Rotating shaft; 24. Partition plate; 25. Arc plate; 26. Automatic multi-leaf regulating valve; 27. Wind hood; 28. Left sealing plate; 29. ​​Right sealing plate; 30. Upper sealing plate; 31. Double door panel; 32. Pedestrian door panel; 33. Automatic pressure relief multi-leaf windshield. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] The present invention discloses a pressurized and oxygenated ventilation system for high altitude construction tunnels. Figure 1 The structure shown includes a hole pressurizing chamber 15, an automatic damper 8, a hard air duct 2 and an exhaust duct 9, wherein:

[0037] The entrance booster chamber 15 is provided at the tunnel entrance. It is a closed space with its front end connected to the tunnel and communicated with the tunnel interior. Its left-right width is greater than the left-right span of the tunnel. The entrance booster chamber 15 maintains a set pressure.

[0038] The right side of the boost chamber 15 near the rear end extends to the right, forming a right channel; its left side extends to the left, forming a left channel. Two dampers are spaced apart in both the right and left channels. Both dampers cannot be opened or closed simultaneously. A first automatic damper 12 and a second automatic damper 11 are spaced apart in the right channel, from right to left. These two dampers cannot be opened or closed simultaneously. A third automatic damper 13 and a fourth automatic damper 14 are spaced apart in the left channel, from left to right. Two automatic dampers in the same channel cannot be opened simultaneously.

[0039] like Figure 5 As shown, the automatic damper 8 is arranged in the tunnel, and forms a closed working space between it and the front tunnel face; the space at the rear end is connected to the booster chamber 15; an openable and closable wind window 33 is provided on the upper part of the automatic damper 8; an air supply pipe is connected to the working space, and the air supply pipe continuously supplies air to the working space to maintain the working space at a high pressure; when the pressure value exceeds the set pressure, the gas in the working space is discharged into the booster chamber 15 through the wind window 33;

[0040] like Figure 4 As shown, the exhaust pipe 9 has its front section located in the portal booster chamber 15, and its rear end passes through the rear side wall of the portal booster chamber 15 and is located outdoors; the exhaust pipe 9 is used to discharge excess gas in the booster chamber 15 to the outdoors; and to maintain the pressure difference between the booster chamber 15 and the working space within the set range. The front section of the exhaust pipe 9 is a horizontal pipe, on which an automatic multi-leaf regulating valve 26 is installed. The rear end of the exhaust pipe 9 is provided with a vertical section, which is vertically upward, and a wind cap 27 is installed on the air outlet at the end of the vertical section. The opening degree of the automatic multi-leaf regulating valve 26 is mainly adjusted according to the second pressure sensor 5B of the portal booster chamber 15. The opening degree of the automatic pressure relief multi-leaf wind window 33 on the automatic damper 8 in the tunnel is determined by the first pressure sensor 5A and the second pressure sensor 5B near the face. If the pressure difference between the pressure near the face and the pressure in the portal booster chamber 15 is too large, and the pressure near the face is large, the opening degree of the automatic pressure relief multi-leaf window 33 on the automatic damper 8 in the tunnel becomes larger, reducing the pressure near the face and reducing the pressure difference between the working space in the tunnel and the portal booster chamber 15. This can achieve gradient pressure distribution before and after the automatic damper 8 in the tunnel, avoiding damage to the damper and other devices due to excessive pressure difference, and at the same time avoiding injury and potential danger to personnel caused by excessive pressure difference.

[0041] Each damper in the right and left channels, as well as the automatic damper 8, comprises a left sealing plate 28, a right sealing plate 29, an upper sealing plate 30, and a split door panel 31. The left sealing plate 28, split door panel 31, and right sealing plate 29 are all vertically arranged side by side from left to right. The upper sealing plate 30 is connected to the upper ends of the left sealing plate 28, split door panel 31, and right sealing plate 29. The upper sealing plate 30 is provided with an automatic pressure relief multi-leaf damper 33. A pedestrian door panel 32 is provided at the lower left end of the split door panel 31. The multi-leaf dampers 33 in each damper in the right and left channels are normally closed.

[0042] Each damper in the right and left channels, as well as the front and rear of the automatic damper 8, are equipped with a first infrared laser sensor 7 and a second infrared laser sensor 6, respectively. When the second infrared laser sensor 6 outside the first and third entrance automatic dampers 12 and 13 senses an oncoming vehicle, it automatically opens the automatic pressure relief multi-leaf damper 33 on the corresponding automatic damper. Once the air pressure inside and outside the automatic damper reaches equilibrium, the split door panels 31 automatically open. Once the first infrared laser sensor 7 senses the passage of a vehicle, the split door panels 31 close. When the infrared laser sensor 6 in front of the second automatic damper senses an oncoming vehicle, it opens the automatic pressure relief multi-leaf damper 33 on the second and fourth automatic dampers 11 and 14. Once the air pressure on both sides reaches equilibrium, the split door panels 31 automatically open. Once the second infrared laser sensor 7 senses the passage of a vehicle, the split door panels 31 close.

[0043] As Figure 2 As shown in 2a and 2b in FIG. 2, a first drainage ditch 19 is excavated on the left or right side in the tunnel hole, and the direction of the first drainage ditch 19 is consistent with the direction of the tunnel; a first sump 20A is excavated on the first drainage ditch 19 in the working space, and close to the automatic air door 8, and the depth of the first sump 20A is lower than the lower end of the automatic air door 8.

[0044] A second drainage ditch is excavated in the portal plenum 15 on the side where the first drainage ditch 19 is located, and the front end of the second drainage ditch is connected to the bottom of the first sump 20A through a first communication pipe 21A, the first communication pipe 21A includes a vertical section connected to the second drainage ditch and a horizontal section connected to the first sump 20A, and the horizontal section is below the ground.

[0045] The rear end of the second drainage ditch is connected to the outside of the portal plenum 15 through a second communication pipe.

[0046] A second sump 20B is excavated in the portal plenum 15 at the side wall, and the second sump 20B is used to receive the sewage discharged by the second drainage ditch, the bottom of the second sump 20B is connected to the horizontal section of the second communication pipe, and the horizontal section is connected to a vertical section; the horizontal section is located below the soil on one side of the side wall of the portal plenum 15 and spans the side wall; the vertical section is vertically upward, and the lower end is connected to the outlet of the horizontal section, and the upper end is used to connect a sewage receiving device.

[0047] The height of the first communication pipe 21A is greater than the water column height of the pressure difference on both sides of the automatic air door 8 in the tunnel, and the height of the second communication pipe 21B is greater than the water column height of the pressure difference on both sides of the side wall of the portal plenum 15.

[0048] As shown in 3a and 3b in FIG. 3, a rotary slagging skip 10 is provided on the side wall at the rear end of the portal plenum 15, the rotary slagging skip 10 includes a cylindrical shell, the cylindrical shell is embedded in the side wall and is enclosed by a plurality of arc-shaped plates 25 connected end to end, and both ends of the cylindrical shell are closed by circular end plates 22; an opening is formed on the cylindrical shell; a rotating shaft 23 is coaxially arranged at the central axis of the cylindrical shell, and both ends of the rotating shaft 23 pass through the circular end plates 22; a plurality of partition plates 24 are arranged on the rotating shaft 23 around the rotating shaft 23, the length of each partition plate 24 is consistent with the direction of the rotating shaft 23, and the width extends to the inner wall of the cylindrical shell, and the circumferentially adjacent two partition plates 24 form an independent space for receiving the slag transported from the tunnel and discharged to the outside of the portal plenum 15 by the rotating shaft 23. The arc-shaped plates 25 are fixedly connected with the side wall of the portal plenum 15 and the circular end plates 22 and do not rotate with the rotating shaft 23. In order to prevent pressure relief, the arc length of each adjacent arc-shaped plate 25 must be greater than the arc length between the two adjacent partition plates 24.

[0049] The air supply pipe comprises a hard air pipe 2, the front end of the hard air pipe 2 passes through the hole pressure chamber 15 and extends through the automatic air door 8, at the front end of the hard air pipe 2 and in the working space, the soft air pipe 3 is connected in the axial direction; the rear end of the hard air pipe 2 passes through the rear side wall of the hole pressure chamber 15 and is located outdoors. The outdoor is provided with a blower 1 connected with the hard air pipe 2. The bypass pipe 17 is communicated on the side wall of the hard air pipe 2 outside the hole pressure chamber 15, and the bypass valve 18 is arranged on the bypass pipe 17. The bypass pipe 17 is arranged on the hard air pipe 2 outside the hole pressure chamber 15, and the bypass valve 18 is arranged on the bypass pipe 17. The bypass pipe 17 prevents backflow caused by excessive wind pressure in the tunnel.

[0050] The automatic air door 8 and the air doors in the right channel and the left channel all comprise a left sealing plate 28, a right sealing plate 29, an upper sealing plate 30 and a pair of door plates 31, the left sealing plate 28, the pair of door plates 31 and the right sealing plate 29 are vertically arranged and arranged in parallel from left to right; the upper sealing plate 30 is connected to the upper ends of the left sealing plate 28, the pair of door plates 31 and the right sealing plate 29, and the automatic pressure relief multi-leaf air window 33 is arranged on the upper sealing plate 30; the human passage door plate 32 is arranged at the lower left end of the pair of door plates 31.

[0051] The application further discloses a ventilation method of the ventilation system for the high-altitude construction tunnel pressure boosting and oxygen increasing, and the ventilation method comprises the following steps.

[0052] Step one, the hole pressure chamber 15 is arranged, the pressure value in the hole pressure chamber 15 is maintained, the air supply pipe continuously supplies air to the working space to maintain the pressure near the working face; when the pressure near the working face is too large, the automatic pressure relief multi-leaf air window 33 of the automatic air door 8 is opened to discharge the excessive gas into the hole pressure chamber 15; when the pressure in the hole pressure chamber 15 is too large and the pressure value between the hole pressure chamber 15 and the working space is too large, the exhaust pipe 9 discharges the excessive gas in the hole pressure chamber 15 to the outdoor;

[0053] Step two, the waste water in the working face construction process is discharged into the first drainage ditch 19 and then flows into the first water collecting pit 20A, the waste water in the first water collecting pit 20A flows into the second drainage ditch through the first connecting pipe 21A and then flows into the second water collecting pit 20B, and the waste water in the second water collecting pit 20B is discharged to the outdoor through the second connecting pipe, thereby completing the pressure relief-free drainage;

[0054] Step three, the soil in the working face construction process is transported into the hole pressure chamber 15 and then is transported out through the rotary slagging skip 10.

[0055] Step 4: When the vehicle passes through the outer dampers of the left and right channels, the outer dampers' automatic pressure relief multi-leaf damper 33 opens. When the pressure inside and outside the outer dampers is balanced, the outer dampers are opened. After the vehicle passes through the outer dampers, the two outer dampers are closed, and the automatic pressure relief multi-leaf damper 33 of the inner damper is opened. When the pressure inside and outside the inner damper is balanced, the inner damper opens, the vehicle enters the tunnel booster chamber 15, and the inner damper is closed.

[0056] When a vehicle passes through the automatic damper 8, the automatic pressure relief multi-leaf window 33 of the automatic damper 8 opens to discharge the gas in the working space. When the air pressure before and after the automatic damper 8 is balanced, the automatic damper 8 opens, and when the vehicle passes through the automatic damper 8, the automatic damper 8 closes.

[0057] In the present invention, a tunnel portal booster chamber and automatic dampers are provided in the tunnel to maintain the face air pressure close to the design requirements. There is no need to set up a separate oxygen supply system, and the oxygen partial pressure is increased by boosting to meet the oxygen supply. The gradient pressure distribution inside the tunnel is achieved by relying on the exhaust pipe and the automatic dampers in the tunnel, avoiding the damage of the dampers due to excessive pressure difference. In addition, the exhaust wind speed is also reduced.

Claims

1. A pressurized and oxygenated ventilation system for high-altitude construction tunnels, characterized in that, The tunnel comprises a tunnel portal pressure chamber, an automatic air door, a hard air pipe and an exhaust pipe, wherein: The tunnel portal pressure chamber is arranged at the tunnel portal and is a closed space connected with the tunnel and the tunnel portal, and has a width greater than the tunnel width; the tunnel portal pressure chamber maintains a set pressure; A right channel is formed by extending rightward at the right side of the rear end of the tunnel portal pressure chamber, and a left channel is formed by extending leftward at the left side of the rear end of the tunnel portal pressure chamber; two air doors are arranged at intervals in the right channel and the left channel, and the two air doors cannot be opened or closed simultaneously in each channel; The automatic air door is arranged in the tunnel and forms a closed working space with the tunnel portal and the tunnel face; the rear end of the automatic air door is connected with the tunnel portal pressure chamber; an automatic pressure relief multi-leaf air window is arranged at the upper portion of the automatic air door; an air supply pipe is connected with the working space to continuously supply air to the working space to maintain a high pressure in the working space; when the pressure value is greater than the set pressure, the gas in the working space is discharged into the tunnel portal pressure chamber through the automatic pressure relief multi-leaf air window; The exhaust pipe is arranged at the front end of the tunnel portal pressure chamber and at the rear end of the exhaust pipe outside the tunnel portal pressure chamber; the exhaust pipe is used to discharge excess gas in the tunnel portal pressure chamber to the outside; the pressure difference between the tunnel portal pressure chamber and the working space is maintained within a set range; A first drainage ditch is excavated at the left or right side of the tunnel, and the first drainage ditch has the same direction as the tunnel; a first sump is excavated on the first drainage ditch in the working space and close to the automatic air door, and the depth of the first sump is lower than the lower end of the automatic air door; A second drainage ditch is excavated in the tunnel portal pressure chamber and at the side where the first drainage ditch is arranged; the front end of the second drainage ditch is connected with the bottom of the first sump through a first communication pipe; the first communication pipe comprises a vertical section connected with the second drainage ditch and a horizontal section connected with the first sump and located below the ground surface; The rear end of the second drainage ditch is connected with the outside of the tunnel portal pressure chamber through a second communication pipe; A second sump is excavated in the tunnel portal pressure chamber and at the side wall; the second sump is used to receive the sewage discharged from the second drainage ditch; the bottom of the second sump is connected with the horizontal section of the second communication pipe; the horizontal section is connected with a vertical section; the horizontal section is located below the soil at the side wall of the tunnel portal pressure chamber and crosses the side wall; the vertical section is vertically upward, and the lower end of the vertical section is connected with the outlet of the horizontal section, and the upper end of the vertical section is used to connect a sewage receiving device; The height of the first communication pipe is greater than the water column height of the pressure difference between the two sides of the automatic air door in the tunnel, and the height of the second communication pipe is greater than the water column height of the pressure difference between the two sides of the side wall of the tunnel portal pressure chamber.

2. The pressurized oxygenation ventilation system for high altitude construction tunnel of claim 1, wherein, A rotary slagging skip is arranged on the side wall at the rear end of the hole entrance plenum, and the rotary slagging skip comprises a cylindrical shell embedded in the side wall, which is enclosed by a plurality of arc-shaped plates connected end to end, and both ends of the cylindrical shell are closed by circular end plates; an opening is formed in the cylindrical shell; a rotating shaft is coaxially arranged at the central axis of the cylindrical shell, and both ends of the rotating shaft pass through the circular end plates; a plurality of partition plates are arranged around the rotating shaft at intervals, and the length of each partition plate is consistent with the direction of the rotating shaft, and the width of each partition plate extends to the inner wall of the cylindrical shell, and the space between two adjacent partition plates is used to accommodate the slag transported out of the tunnel and is discharged outside the hole entrance plenum by the rotating shaft.

3. The pressurized oxygenation ventilation system for high altitude construction tunnel of claim 2, wherein, The air supply pipe comprises a hard air pipe, the front end of the hard air pipe passes through the hole entrance plenum and extends through the automatic air door, and a soft air pipe is connected to the front end of the hard air pipe in the working space; the rear end of the hard air pipe passes through the rear side wall of the hole entrance plenum and is located outside the chamber.

4. The pressurized oxygenation ventilation system for high altitude construction tunnel of claim 3, wherein, Each air door in the right channel and the left channel, and the automatic air door all comprise a left sealing plate, a right sealing plate, an upper sealing plate and a pair of door plates, the left sealing plate, the pair of door plates and the right sealing plate are vertically arranged and arranged side by side from left to right; the upper sealing plate is connected to the upper end of the left sealing plate, the pair of door plates and the right sealing plate, and an automatic pressure relief multi-leaf air window is formed in the upper sealing plate; a pedestrian door plate is arranged at the lower left end of the pair of door plates.

5. The ventilation method for the pressurization and oxygenation ventilation system of the high-altitude construction tunnel according to any one of claims 1-4, characterized in that, The ventilation method comprises the following steps: Step one, a hole entrance plenum is arranged, the pressure value in the hole entrance plenum is maintained, the air supply pipe continuously supplies air to the working space to maintain the pressure near the working face; when the pressure near the working face is too high, the automatic pressure relief multi-leaf air window of the automatic air door is opened to discharge the excess gas into the hole entrance plenum; when the pressure in the hole entrance plenum is too high and the pressure value between the hole entrance plenum and the working space is too high, the exhaust pipe discharges the excess gas in the hole entrance plenum to the outside of the chamber; Step two, the wastewater generated during the construction of the working face is discharged into the first drainage ditch, and then flows into the first sump, the wastewater in the first sump flows into the second drainage ditch through the first communication pipe, and then flows into the second sump, and the wastewater in the second sump is discharged to the outside through the second communication pipe, thereby completing the pressure-free drainage; Step three, the soil during the construction of the working face is transported into the hole entrance plenum and is transported out by the rotary slagging skip; When a vehicle passes through the air doors on the outer sides of the left channel and the right channel, the automatic pressure relief multi-leaf air windows of the outer air doors are opened, the outer air doors are opened when the pressure inside and outside the outer air doors is balanced, the vehicle passes through the outer air doors, the two outer air doors are closed, the automatic pressure relief multi-leaf air windows of the inner air doors are opened, and the inner air doors are opened when the pressure inside and outside the inner air doors is balanced, the vehicle enters the hole entrance plenum, and the inner air doors are closed; When a vehicle passes through the automatic air door, the automatic pressure relief multi-leaf air window of the automatic air door is opened to discharge the gas in the working space, and the vehicle passes through the automatic air door when the air pressure before and after the automatic air door is balanced.

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