CN113217070B - Novel tunnel construction ventilation system based on high-pressure air supply and ventilation method thereof - Google Patents

Novel tunnel construction ventilation system based on high-pressure air supply and ventilation method thereof Download PDF

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CN113217070B
CN113217070B CN202110707960.1A CN202110707960A CN113217070B CN 113217070 B CN113217070 B CN 113217070B CN 202110707960 A CN202110707960 A CN 202110707960A CN 113217070 B CN113217070 B CN 113217070B
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air
tunnel
pressure
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ventilation
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CN113217070A (en
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田宝华
张彪
刘延龙
赵永明
陈文萍
余龙文
谢高英
刘咏梅
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China Railway 23rd Bureau Group Co Ltd
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F1/00—Ventilation of mines or tunnels; Distribution of ventilating currents
    • E21F1/08—Ventilation arrangements in connection with air ducts, e.g. arrangements for mounting ventilators
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F1/00—Ventilation of mines or tunnels; Distribution of ventilating currents
    • E21F1/04—Air ducts
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F1/00—Ventilation of mines or tunnels; Distribution of ventilating currents
    • E21F1/08—Ventilation arrangements in connection with air ducts, e.g. arrangements for mounting ventilators
    • E21F1/085—Ventilation arrangements in connection with air ducts, e.g. arrangements for mounting ventilators using compressed gas injectors
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
    • E21F17/02—Suspension devices for tubes or the like, e.g. for ventilating ducts
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
    • E21F17/18—Special adaptations of signalling or alarm devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/30—Wind power
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction

Abstract

The invention discloses a novel tunnel construction ventilation system based on high-pressure air supply and a ventilation method thereof, relating to the technical field of tunnel construction ventilation, wherein the ventilation system comprises an air supply power system and an air flow conveying system, and the air supply power system is arranged at the inlet of a tunnel to form high-speed air flow; the air flow conveying system is arranged in the tunnel and can extend to the tunnel inlet to be connected with the air supply power system, and is used for conveying high-pressure air flow into the tunnel; the airflow conveying system comprises a high-pressure conveying section and an airflow diffusion section; so that high-speed airflow formed by the wind power supply system can sequentially pass through the high-pressure conveying section and the airflow diffusion section to enter the vicinity of the tunnel face and form dispersed airflow; through implementing this technical scheme, aim at solving current tunnel construction ventilation system air feed not enough, lag construction progress scheduling problem, can effectively ensure the construction progress and the safety of little section long distance tunnel, ventilation efficiency is high, the wind damage is little, the durability is strong, can effectively reduce equipment fortune maintenance cost.

Description

Novel tunnel construction ventilation system based on high-pressure air supply and ventilation method thereof
Technical Field
The invention relates to the technical field of tunnel construction ventilation, in particular to a novel tunnel construction ventilation system based on high-pressure air supply and a ventilation method thereof, which are suitable for a small-section long-distance tunneling tunnel.
Background
With the continuous development of the construction technology of the civil infrastructure engineering in China, the tunnel engineering with the characteristics of small section and long tunnel is increased day by day, the tunnel of the type has the characteristics of small opening section and deep tunnel, the arrangement of the construction branch holes in the tunnel is gradually complicated with the increase of the tunneling depth of the tunnel, and the environment in the tunnel is gradually worsened due to the difficulty in removing pollutants such as dust, CO and the like, so that the construction ventilation becomes a prominent difficult problem influencing the construction safety and quality of the small section and long tunnel.
According to the inventor, in the process of implementing the embodiment, the existing small-section long-distance tunneling tunnel has at least the following defects: firstly, the construction method is limited by a clearance section, large-scale ventilation equipment is difficult to use, which is contrary to increasingly harsh construction environments, and as the tunneling distance is increased, the conventional ventilation system is often difficult to meet the requirement of air quantity required for construction in a hole, so that the construction environment is severe, the safety of constructors is difficult to guarantee, the section arrangement is dense, the traffic transportation in the hole is seriously influenced, and the construction progress is delayed; secondly, along with the tunneling of the tunnel, the flexible air pipes arranged in the tunnel are easy to be damaged locally due to long-time suspension, and the damage is more serious along with the passage of time and is far larger than the theoretical air leakage value within an acceptable range, so that the efficiency of the fan is low, the energy consumption loss is serious, and the requirement of the actual environment in the tunnel cannot be met; third, flexible tuber pipe outside profile does not possess the plastic shape, very easily appears the tuber pipe shape variation and causes intraductal local resistance to strengthen in local corner, and the wind decreases seriously, and local fold also changes with stress concentration and makes the tuber pipe damaged, forms vicious circle.
In view of the above technical problems, it is necessary for those skilled in the art to develop a novel ventilation system/method for tunnel construction to solve the problem of ventilation in the existing tunnel construction, and especially to adapt to the tunnel with a small opening section and a deep tunnel construction environment.
Disclosure of Invention
Aiming at the technical problems, the invention aims to provide a novel tunnel construction ventilation system based on high-pressure air supply, and aims to solve the problems of insufficient air supply, delayed construction progress and the like of the conventional tunnel construction ventilation system.
The technical scheme adopted by the invention is as follows:
a novel tunnel construction ventilation system based on high-pressure air supply is disclosed, wherein the tunnel comprises a tunnel right-line main hole, an auxiliary transverse channel and a tunnel left-line main hole or a parallel pilot hole which is communicated with the tunnel right-line main hole through the auxiliary transverse channel; the ventilation system includes:
a wind power supply system arranged at a tunnel entrance to form a high velocity air stream;
the air flow conveying system is arranged in the tunnel and can extend to the inlet of the tunnel to be connected with the air supply power system, and is used for conveying high-pressure air flow into the tunnel;
the airflow conveying system comprises a high-pressure conveying section consisting of a plurality of equal-diameter high-pressure hard air pipes and an airflow diffusion section consisting of at least one gradually-variable-diameter high-pressure hard air pipe; the one end and the air feed driving system that the high pressure transported the section are connected, and the other end and the air current diffusion section concatenation of high pressure transport section, the high-pressure stereoplasm tuber pipe of gradual reducing arranges near tunnel face operation section in order to make to pass through the high-speed air current that air feed driving system formed can pass through in order the high pressure transport the section with air current diffusion section gets into near the face and forms the diffuse type wind current.
The technical scheme includes that an air supply power system is used as air flow driving force of a tunnel, an air flow conveying system is configured to guide high-pressure air flow, the air flow conveying system is composed of a high-pressure conveying section composed of equal-diameter high-pressure hard air pipes and an air flow diffusion section composed of gradually-changed-diameter high-pressure hard air pipes, local damage caused by long-time hanging operation of a ventilation system is overcome to a great extent, operation and maintenance are more convenient, the air flow conveying system is combined with the design of the air supply power system in the technical scheme, air speed flowing can be effectively guaranteed in the high-pressure conveying section, uniform diffusion of the air flow on a tunnel face can be effectively guaranteed in the air flow diffusion section, the problems that air loss is too large due to the fact that air pipes are mixed in a tunnel and damaged, ventilation efficiency is low, construction is disturbed, construction progress is slow and the like due to the fact that a section clearance is too small are solved, and the air flow conveying system has good application prospect and popularization and use values.
Preferably, in the technical scheme, the air supply power system comprises an axial flow fan and an air booster pump, the axial flow fan is connected with the air booster pump through a soft air pipe, and the air supply power system is arranged in the range of 10-20m outside the tunnel left line positive hole or the parallel pilot tunnel; the air supply power system adopts the combined design of the air booster pump and the axial flow fan to form a novel high-pressure air supply system, fresh air outside the tunnel is supplied through the axial flow fan, the arrangement design of the air supply power system can effectively prevent the air from being sucked into the tunnel to be discharged and polluted air, and the high-speed fresh air flow can be effectively supplied into the tunnel by combining the mode that the air booster pump supplies power to output high-speed air flow; and the air booster pump in this technical scheme is preferred to be connected with axial fan through the flexible two soft tuber pipes of anti of PVC to ventilation system construction.
Preferably, in the above technical solution, the high-pressure transportation section includes a first high-pressure transportation section and a second high-pressure transportation section respectively connected to the wind supply power system; the air flow diffusion section comprises a first air flow diffusion section communicated with the first high-pressure transportation section and a second air flow diffusion section communicated with the second high-pressure transportation section, and the first air flow diffusion section is arranged near a tunnel face A of a tunnel left-line main tunnel or a parallel pilot tunnel tunneled forwards; the second airflow diffusion section is arranged near a tunnel face B of the tunnel right-line forward tunnel; the technical scheme is that an airflow conveying system is designed into a parallel drainage design by combining with a tunnel structure design, high-pressure airflow is introduced into a first airflow diffusion section through a first high-pressure conveying section, and the first airflow diffusion section is finally stopped near a tunnel face A so as to be diffused into stable dispersed airflow at the tunnel face A; meanwhile, high-pressure airflow is introduced into the second airflow diffusion section through the second high-pressure transportation section, the second airflow diffusion section is finally stopped near the tunnel face B to diffuse into stable dispersed airflow at the tunnel face B, and the airflow conveying system adopts a parallel drainage design, so that the air pressure is less damaged, and the purposes of high ventilation efficiency and stable airflow conveying are achieved.
Preferably, in the technical scheme, the axial flow fan comprises a first axial flow fan and a second axial flow fan, the air booster pump comprises a first air booster pump and a second air booster pump, an air inlet of the first air booster pump is connected with the first axial flow fan through a first soft air pipe, and an air supply end of the first air booster pump is communicated with the first high-pressure transportation section; an air inlet of the air booster pump II is connected with the axial flow fan II through a soft air pipe II, and an air supply end of the air booster pump II is communicated with the second high-pressure transportation section; the technical scheme combines the wind power supply system and the airflow conveying system to be designed in a parallel mode, can further ensure the wind pressure entering respective wind channels, accelerates the wind speed flow in the tunnel, and is suitable for the structural characteristics of small-section tunnels due to small section clearance.
Preferably, the air booster pump is single-air-source boosting equipment, and can increase the air pressure of the air supply system by 3-5 times; according to the technical scheme, the air booster pump is preferably a single-air-source booster device, so that the reliability is high, the maintenance-free service life is long, and the output efficiency is stable.
Above-mentioned technical scheme is preferred, ventilation system still includes the efflux fan of arranging at supplementary cross passageway, tunnel right side line positive hole to outside air drainage in the tunnel to combine above-mentioned air supply driving system and air current conveying system's design, for the face evenly carries fresh air, ensured the construction progress and the safety of little section long distance tunnel.
Preferably, in the technical scheme, the first high-pressure transportation section comprises a plurality of equal-diameter high-pressure hard air pipes A which are sequentially spliced and connected, the second high-pressure transportation section comprises a plurality of equal-diameter high-pressure hard air pipes B which are sequentially spliced and connected, and the diameters of the equal-diameter high-pressure hard air pipes A and the equal-diameter high-pressure hard air pipes B are 0.4-0.6m; the technical scheme includes that the diameters of an equal-diameter high-pressure hard air pipe A and an equal-diameter high-pressure hard air pipe B are designed into small-diameter pipelines, the specific diameters are determined according to the size of an actual tunnel construction section, and according to clearance limitation, under the condition that normal construction of construction vehicles and instruments in a tunnel is guaranteed, a larger pipeline diameter is selected to provide larger air volume demand for a tunnel face in unit time; the gradient-diameter high-pressure hard air pipe of the air flow diffusion section is arranged near the tunnel face operation section, a large-sized slag discharging vehicle in the tunnel does not operate in the section, the diameter of the gradient-diameter high-pressure hard air pipe is gradually enlarged from the diameter of the equal-diameter air pipe to the size of a conventional air pipe, the size of the conventional air pipe is 1200-1800 mm, and high-pressure air flow is diffused so as to replace polluted air in the tunnel in a wider range on the premise of ensuring normal construction in the tunnel.
In the above technical scheme, preferably, the equal-diameter high-pressure hard air pipe and the gradually-changed-diameter high-pressure hard air pipe are made of one or more of PVC, galvanized sheet iron, PP all-plastic polypropylene and steel lining plastic, but are not limited thereto, and all the hard pipeline materials having the advantages of high pressure, light weight, wear resistance, corrosion resistance and the like are within the protection scope of the invention; this embodiment ventilation system is equipped with the high-efficient guide air current of minor diameter stereoplasm tuber pipe, and the effectual tuber pipe that has reduced takes up an area of, and has accelerated the interior wind speed of hole and flow.
Preferably, in the technical scheme, the first air flow diffusion section comprises a high-pressure hard air pipe a with a gradually-changed diameter, which extends from the tail end of the first high-pressure transportation section to the position near the palm surface a, the second air flow diffusion section comprises a high-pressure hard air pipe B with a gradually-changed diameter, which extends from the tail end of the second high-pressure transportation section to the position near the palm surface B, and drain holes are uniformly arranged on the outer contour surfaces of the high-pressure hard air pipe a with the gradually-changed diameter and the high-pressure hard air pipe B with the gradually-changed diameter and are used for shunting the high-pressure air flow at the tail end; this technical scheme is preferred evenly to be arranged circular discharge orifice on near face stereoplasm gradual change footpath high pressure stereoplasm tuber pipe, carry out reposition of redundant personnel processing to the terminal high-pressure draught of drainage, can effectively reduce the interior air current pressure of pipeline, slow down the efflux wind speed, and can evenly carry fresh air to the face with the mode of filling up, avoided in the hole air return speed too big influence other construction equipment or because high-pressure column air current fails in time the diffusion and leads to the unable scheduling problem that clears away of local pollutant, this structural design is ingenious reasonable.
Preferably, in the above technical solution, the ventilation system further comprises a secondary pressurization system, the secondary pressurization system comprises a third air booster pump arranged in the first high-pressure transportation section and a fourth air booster pump arranged in the second high-pressure transportation section, and the secondary pressurization system is used for carrying out secondary or multiple pressurization on the air flow entering the air flow transportation system; according to the technical scheme, the ventilation system is provided with the air multi-time pressurization system according to the tunneling depth of the tunnel, the limit ventilation distance of the tunnel can be effectively prolonged, the starting number of the pressurization equipment is selected according to the actual situation, the construction environment in the tunnel is effectively guaranteed on the premise of high efficiency and energy conservation, and the ventilation system has high economic value; and the wind supply transportation mode of the novel ventilation system has wide application scenes, including but not limited to the use of the small-section tunnel scene, and the high-pressure wind flow wind supply technology can be effectively integrated with a plurality of traditional tunnel construction ventilation systems, so that a new thought is opened for ventilation design.
On the other hand, the invention also provides a ventilation method of the novel tunnel construction ventilation system based on high-pressure air supply, which comprises the following steps:
s1, analyzing a pollution source in a tunnel and determining a ventilation standard;
s2, designing a ventilation system;
s3, calculating ventilation parameters of the tunnel, and implementing a ventilation scheme;
the ventilation system in step S2 specifically includes: a wind power supply system is arranged at the inlet of the tunnel to form high-speed airflow; an airflow conveying system is adopted to convey high-pressure airflow in the tunnel, the airflow conveying system comprises a high-pressure conveying section consisting of a plurality of equal-diameter high-pressure hard air pipes and an airflow diffusion section consisting of at least one gradually-variable-diameter high-pressure hard air pipe, a secondary pressurization system is additionally arranged in the high-pressure conveying section, and a drainage hole is additionally arranged in the airflow diffusion section to form uniform dispersed airflow near the tunnel face;
the step S3 of calculating the ventilation parameters of the tunnel specifically includes: calculating the number and the arrangement distance of the air booster pumps in the secondary boosting system in the step S2; calculating the arrangement parameters of the drain holes in the airflow diffusion section;
wherein evenly arrange the discharge orifice at the air current diffusion section, shunt the processing to terminal high-pressure draught, can effectively reduce the interior air current pressure of pipeline, slow down the efflux wind speed to can evenly carry fresh air to the face with the mode of filling up, the specific parameter of arranging of discharge orifice calculates according to the following formula:
Figure SMS_1
wherein n is the number of drain holes; a. The 1 Is the area (m) of the discharge hole 2 ) (ii) a C is the supercharging multiple (times) of the supercharging equipment; w p Providing initial wind pressure (Pa) for an axial flow fan of a ventilation system; v. of 1 、v b Respectively the wind speeds (m/s) of the outlet of the vent hole and the outlet of the gradual change section air pipe; q is the air quantity (m) required by the palm surface 3 /s)；d a 、 d b The diameters (m) of an inlet and an outlet of the gradual change section air pipe are shown; k 1 、K 2 、K 3 、M 1 、M 2 The formula coefficients are respectively taken as follows: k 1 ＝1.66、K 2 ＝17795.4、K 3 ＝1；M 1 ＝0.79、M 2 =1; the other parameters can be obtained according to the actual engineering or design requirements;
the number and the arrangement distance of the air booster pumps in the secondary booster system are calculated according to the following formula:
Figure SMS_2
wherein L is a device arrangement pitch (m); k is a formula correlation coefficient; n is the supercharging effect (multiple) of the supercharging equipment; d is the diameter (m) of the high-pressure air pipe; w p Providing initial wind pressure (Pa) for an axial flow fan of a ventilation system; λ is the coefficient of friction of the pipeline, Q 1 Air quantity (m) required for construction face 3 (s), N is the number of equipment arrangements (stations); d is the ventilation length (m) of the tunnel, and all parameters can be obtained according to construction sites or design requirements.
The invention has at least the following beneficial effects:
1. the ventilation system of the invention takes an air supply power system as the air flow driving force of the tunnel, and is provided with an air flow conveying system for guiding high-pressure air flow, wherein the air flow conveying system consists of a high-pressure conveying section consisting of equal-diameter high-pressure hard air pipes and an air flow diffusion section consisting of gradually-changed-diameter high-pressure hard air pipes, and finally, a diffusion type air flow is formed near the tunnel face, so that a novel air supply system integrating air supply, pressurization and conveyance is formed, the novel air supply system is particularly suitable for long-distance air supply of a small-section long-distance tunnel, and the construction progress and safety of the small-section long-distance tunnel can be effectively guaranteed.
2. The ventilation system air supply power system adopts the axial flow fan to combine with the air booster pump to provide driving force for tunnel air flow, and is matched with the small-diameter hard air pipe to efficiently guide the air flow, so that the air pipe occupation of a high-pressure transportation section and an air flow diffusion section in an air flow transportation system is effectively reduced, the air flow in a tunnel is accelerated, and the problems of excessive air loss, low ventilation efficiency, construction disturbance, slow construction progress and the like caused by equipment mixing in the tunnel and air pipe damage due to the fact that the section clearance in a small-section tunnel is too small are solved.
3. The high-pressure transport section and the airflow diffusion section of the airflow conveying system both adopt high-pressure hard air pipes, the inner walls of the high-pressure hard air pipes are smooth, the durability is strong, the local damage caused by long-time suspension operation of the airflow conveying system is overcome to the greatest extent, and the operation and maintenance are more convenient; and the customized arc-shaped hard air pipe used at the corner of the air flow conveying system can effectively avoid the problems of sharp increase of local resistance at the bent part of the conventional soft air pipe, serious deformation of the air pipe and the like.
4. According to the invention, a secondary supercharging system is designed according to the tunneling depth of the tunnel, the secondary supercharging system is arranged in the high-pressure transportation section, and the number and the arrangement distance of the air supercharging pumps in the secondary supercharging system are obtained through accurate calculation, so that the limit ventilation distance of the tunnel can be effectively prolonged, the starting number of supercharging equipment is selected according to actual conditions, the construction environment in the tunnel is effectively guaranteed on the premise of high efficiency and energy conservation, and the secondary supercharging system has high economic value; and the wind supply transportation mode of the novel ventilation system has wide application scenes, including but not limited to the use of the small-section tunnel scene, and the high-pressure wind flow wind supply technology can be effectively integrated with a plurality of traditional tunnel construction ventilation systems, so that a new thought is opened for ventilation design.
5. The airflow diffusion section adopts the design of the vent holes, preferably, the circular vent holes are uniformly distributed on the hard gradient-diameter high-pressure hard air pipe near the tunnel face, the high-pressure airflow at the drainage end is subjected to flow dividing treatment, the airflow pressure in the pipeline can be effectively reduced, the jet flow wind speed is reduced, fresh air can be uniformly conveyed to the tunnel face in a diffused mode, the problems that other construction instruments are influenced by the overlarge air return speed in the tunnel or local pollutants cannot be removed due to the fact that high-pressure columnar airflow cannot be diffused in time and the like are solved, and the structural design is ingenious and reasonable.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and it is obvious for those skilled in the art that other related drawings can be obtained according to these drawings without inventive efforts.
FIG. 1 is a schematic plan view of a ventilation system utilizing an embodiment of the present invention;
FIG. 2 is a wind flow path diagram for dirty wind discharge using a ventilation system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the cross-sectional layout of the gas flow delivery system in a tunnel according to an embodiment of the present invention;
FIG. 4 is a front view of an isometric high-pressure rigid air duct of a high-pressure transportation section in an embodiment of the invention;
FIG. 5 is a front view of a high-pressure hard air duct with a gradually-changed diameter of an airflow diffuser in an embodiment of the invention;
FIG. 6 is a side view of a high pressure rigid air hose of an air delivery system in an embodiment of the present invention;
FIG. 7 is a schematic illustration of the splicing of adjacent high pressure rigid air ducts of an air delivery system according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a flexible rubber gasket in a high-pressure rigid air duct according to an embodiment of the present invention.
In the figure: 1 a-a first axial flow fan; 1 b-an axial flow fan II; 2 a-a soft air duct I; 2 b-a soft air duct II; 3 a-a first air booster pump; 3 b-an air booster pump II; 3 c-air booster pump III; 3 d-air booster pump IV; 4 a-a first high-pressure transport section; 4 b-a second high-pressure transport section; 4 c-a first gas flow diffuser section; 4 d-a second gas flow diffuser section; 5-parallel pilot tunnel; 6-tunnel right line main hole; 7-at the entrance of the parallel guide tunnel; 8, a right line positive hole inlet of the tunnel; 9-face A; 10-an auxiliary transverse channel; 11-face B; 12-a jet fan; 13-fresh air; 14-high pressure fresh air; 15-polluted wind; 16-a flange; 17-equal-diameter high-pressure hard air pipes; 18-a fixation device; 19-a gradient-diameter high-pressure hard air pipe; 20-high pressure hard air duct outer wall; 21-flange connection holes; 22-flange joint screws; 23-flange joint nuts; 24-a soft gel seal; 25-a drain hole.
Detailed Description
The invention is further described with reference to the following figures and specific embodiments.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Example one
Referring to fig. 1 to 3, the present embodiment provides a novel tunnel construction ventilation system based on high-pressure air supply, which is applied to a small-section tunnel, where the tunnel includes a right-side tunnel main tunnel inlet 8, an auxiliary cross channel 10, and a left-side tunnel main tunnel or a parallel pilot tunnel connected to the right-side tunnel main tunnel inlet 8 through the auxiliary cross channel 10, and the present embodiment takes the parallel pilot tunnel 5 as an example; in particular, the ventilation system of the embodiment comprises an air supply power system and an air flow delivery system, wherein the air supply power system is arranged at the entrance of the tunnel, the air supply power system of the embodiment is arranged at the entrance 7 of the parallel guide tunnel, and the air supply power system is used for forming high-speed air flow; the air flow conveying system is arranged in the tunnel hole and can extend to the entrance of the tunnel in a network conveying mode to be connected with the air supply power system, and is used for conveying high-pressure air flow into the tunnel.
The airflow conveying system provided by the embodiment comprises a high-pressure conveying section and an airflow diffusion section, wherein the high-pressure conveying section is composed of a plurality of equal-diameter high-pressure hard air pipes 17, the airflow diffusion section is composed of at least one gradually-diameter high-pressure hard air pipe 19, the front end of the high-pressure conveying section is connected with the output end of an air supply power system, and the tail end of the high-pressure conveying section is spliced and communicated with the airflow diffusion section; the high-pressure hard air pipe 19 with the gradually changed diameter is arranged near the tunnel face operation section, so that high-speed air flow formed by the air supply power system can sequentially pass through the high-pressure transportation section and the air flow diffusion section to enter the vicinity of the tunnel face and form dispersed air flow.
In some embodiments, the air supply power system comprises an axial flow fan and an air booster pump, the axial flow fan is connected with the air booster pump through a soft air pipe, fresh air 13 outside the tunnel is supplied through the axial flow fan, and the fresh air 13 passes through the air booster pump to form high-pressure fresh air 14 to be supplied to the air flow conveying system, so that the ventilation system of the embodiment is a tunnel construction high-pressure ventilation system which takes the air supply power system integrated by the axial flow fan and the air booster pump as driving force and conveys the driving force through a hard high-pressure pipeline network; and the wind power supply system is arranged in the range of 10-20m outside the parallel guide tunnel 5, so that polluted wind 15 can be effectively prevented from being sucked into the tunnel and discharged; in some embodiments, the air booster pump is preferably connected to the axial flow fan through a PVC flexible double-resistant soft air pipe to facilitate construction of the ventilation system.
In some embodiments, the high pressure transport section comprises a first high pressure transport section 4a and a second high pressure transport section 4b, respectively connected to the wind power supply system; the airflow diffusion section comprises a first airflow diffusion section 4c communicated with the first high-pressure transportation section 4a and a second airflow diffusion section 4d communicated with the second high-pressure transportation section 4b, and the first airflow diffusion section 4c is arranged near a tunnel face A9 where the parallel pilot tunnel 5 is tunneled forwards; the second airflow diffusion section 4d is arranged near a tunnel face B11 tunneled forwards by the right tunnel entrance 8 of the tunnel; the airflow conveying system is designed into a parallel drainage design by combining with a tunnel structure design, high-pressure airflow is introduced into a first airflow diffusion section 4c through a first high-pressure conveying section 4a, and the first airflow diffusion section 4c is finally stopped near a tunnel face A9 so as to be diffused into stable dispersed airflow at the tunnel face A9; meanwhile, the second high-pressure transportation section 4B extends forwards to an auxiliary transverse channel 10 along the parallel pilot tunnel 5, then enters a right-line main tunnel inlet 8 of the tunnel through the auxiliary transverse channel 10 and is communicated with a second airflow diffusion section 4d, high-pressure airflow is introduced into the second airflow diffusion section 4d, and the second airflow diffusion section 4d is finally stopped near a tunnel face B11 to be diffused into stable dispersed airflow at the tunnel face B11.
In some embodiments, the axial flow fan comprises a first axial flow fan 1a and a second axial flow fan 1b, the air booster pump comprises a first air booster pump 3a and a second air booster pump 3b, an air inlet of the first air booster pump 3a is connected with the first axial flow fan 1a through a soft air pipe 2a, and an air supply end of the first air booster pump 3a is communicated with the first high-pressure transportation section 4 a; an air inlet of the air booster pump II 3b is connected with the axial flow fan II 1b through a soft air pipe II 2b, and an air supply end of the air booster pump II 3b is communicated with the second high-pressure transportation section 4b; in the embodiment, the air supply power system and the air flow conveying system are combined and designed into a parallel type, so that the air pressure entering each air channel can be further ensured, the air speed flowing in the tunnel is accelerated, and the method is suitable for the structural characteristic that the clearance of the section is too small in a small-section tunnel; preferably, the air booster pump provided by the embodiment is a single-air-source supercharging device, the air pressure of the air supply system can be increased by 3-5 times, and the single-air-source supercharging device has the characteristics of high reliability, no maintenance, long service life and stable output efficiency.
In some embodiments, the ventilation system further comprises a jet fan 12 arranged at the auxiliary cross passage 10 and the right-line main tunnel inlet 8 of the tunnel, so that polluted air 15 in the tunnel is guided to the outside of the tunnel, and fresh air is uniformly conveyed to the tunnel face by combining the design of the air supply power system and the air flow conveying system, so that the construction progress and the safety of the small-section long-distance tunnel are guaranteed.
Referring to fig. 4 to 7, in the illustrated embodiment, the first high-pressure transportation section 4a includes a plurality of equal-diameter high-pressure hard air ducts a connected in sequence; the second high-pressure transportation section 4B comprises a plurality of equal-diameter high-pressure hard air pipes B which are sequentially spliced and connected; the length of each of the equal-diameter high-pressure hard air pipes A and the equal-diameter high-pressure hard air pipes B is 20-30 m, the length of each of the equal-diameter high-pressure hard air pipes 17 is 30m, two adjacent equal-diameter high-pressure air pipes A are connected through flanges 16 and hung at the arch tops of the tunnels through fixing devices 18, two adjacent equal-diameter high-pressure hard air pipes B are connected through flanges 16 and hung at the arch tops of the tunnels through fixing devices 18, soft colloid sealing gaskets 24 are filled at the butt joints of the flanges 16, and after the flanges 16 are connected, aluminum sealing belts are used for sealing, so that air leakage of pipelines caused by pipeline connection is reduced to the maximum extent, and air volume loss is reduced; specifically, a high-pressure pipeline connecting flange 16 is arranged on the outer wall 20 of two high-pressure hard air pipes which are spliced with each other, flange connecting holes 21 are uniformly arranged on the flange 16 and a soft colloid sealing gasket 24 in the circumferential direction and are fixed through flange connecting screws 22 and flange connecting nuts 23, and particularly, a specific arc-shaped hard air pipe is customized according to the included angle of two roadways in the place where a pipeline turns, so that the air resistance of the air pipe is reduced; correspondingly, the first air flow diffusion section 4c comprises a high-pressure hard air pipe A with a gradually-changed diameter, which extends from the tail end of the first high-pressure transportation section 4a to the vicinity of the tunnel face A9, and the second air flow diffusion section 4d comprises a high-pressure hard air pipe B with a gradually-changed diameter, which extends from the tail end of the second high-pressure transportation section 4B to the vicinity of the tunnel face B11; the tail ends of the gradient-diameter high-pressure hard air pipe A and the equal-diameter high-pressure hard air pipe A have the same diameter and are connected by adopting a flange 16, a soft colloid sealing gasket 24 is also filled at the butt joint part of the flange 16, and an aluminum sealing tape is used for sealing after the flanges 16 are connected; in particular, the diameters of the equal-diameter high-pressure hard air pipes a and the equal-diameter high-pressure hard air pipes B are 0.4 to 0.6m, the diameters of the equal-diameter high-pressure hard air pipes a and the equal-diameter high-pressure hard air pipes B are designed to be small-diameter pipelines, the specific diameters are determined according to the size of an actual tunnel construction section, and according to clearance limitation, under the condition that normal construction of construction vehicles and instruments in a tunnel is guaranteed, a larger pipeline diameter is selected to provide larger air demand for a tunnel face in unit time; the gradient-diameter high-pressure hard air pipe 19 of the air flow diffusion section is arranged near the tunnel face operation section, a large-sized slag-tapping vehicle in the tunnel does not operate in the section, the diameter of the gradient-diameter high-pressure hard air pipe 19 is gradually enlarged from the diameter of the equal-diameter air pipe to the conventional air pipe, the conventional air pipe is 1200-1800 mm, and high-pressure air flow is diffused so as to replace polluted air 15 in the tunnel in a wider range on the premise of ensuring normal construction in the tunnel.
In some embodiments, the equal-diameter high-pressure hard air pipe 17 and the gradient-diameter high-pressure hard air pipe 19 are made of one or more of PVC, galvanized iron sheet, PP all-plastic polypropylene and steel lining plastic, and in this embodiment, the equal-diameter high-pressure hard air pipe 17 and the gradient-diameter high-pressure hard air pipe 19 are made of PP all-plastic polypropylene; certainly, the invention is not particularly limited to the above, and all the hard pipeline materials with the advantages of high pressure, light weight, wear resistance, corrosion resistance and the like can be applied to the small-section tunnel within the protection scope of the invention; this embodiment ventilation system is equipped with the high-efficient guide air current of minor diameter stereoplasm tuber pipe from this, and the effectual tuber pipe that has reduced takes up an area of, and has accelerated the interior wind speed of hole and flow.
Referring to fig. 1 and 2, the air flow path of the novel ventilation system of the tunnel of the present embodiment is:
pollutant wind flow path of tunnel face A of parallel pilot tunnel 5: an inlet of a parallel pilot tunnel 5, a section of the parallel pilot tunnel 5, a tunnel face of the parallel pilot tunnel 5, an auxiliary transverse passage 10, an inlet 8 section of a right main tunnel of the tunnel and an inlet 8 of the right main tunnel of the tunnel;
pollutant wind flow path of right tunnel entrance 8 tunnel face B: an inlet of a parallel pilot tunnel 5, an auxiliary transverse channel 10, a tunnel right line main tunnel inlet 8 face, a tunnel right line main tunnel inlet 8 section and a tunnel right line main tunnel inlet 8 inlet.
In conclusion, the ventilation system of the invention takes an air supply power system as the air flow driving force of the tunnel, and is provided with an air flow conveying system for guiding high-pressure air flow, wherein the air flow conveying system consists of a high-pressure conveying section consisting of equal-diameter high-pressure hard air pipes 17 and an air flow diffusion section consisting of gradually-diameter high-pressure hard air pipes 19, and finally, a dispersed air flow is formed near the tunnel face, so that a novel air supply system integrating air supply, pressurization and conveyance is formed, and the invention is particularly suitable for long-distance air supply of a small-section tunnel, and can effectively ensure the construction progress and safety of the small-section long-distance tunnel; firstly, the ventilation system air supply power system adopts an axial flow fan to combine with an air booster pump to provide driving force for tunnel air flow, and is matched with a small-diameter hard air pipe to efficiently guide the air flow, so that the air pipe occupation of a high-pressure transport section and an air flow diffusion section in an air flow conveying system is effectively reduced, the air flow in a tunnel is accelerated, and the problems of large air loss, low ventilation efficiency, construction disturbance, slow construction progress and the like caused by equipment mixing in the tunnel and air pipe damage due to undersized section clearance in a small-section tunnel are solved; secondly, the high-pressure transport section and the airflow diffusion section of the airflow conveying system both adopt high-pressure hard air pipes, the inner walls of the high-pressure hard air pipes are smooth and have strong durability, the local damage caused by long-time suspension operation of the airflow conveying system is overcome to a great extent, and the operation and maintenance are more convenient; and the customized arc-shaped hard air pipe used at the corner of the air flow conveying system can effectively avoid the problems of sharp increase of local resistance at the bent part of the conventional soft air pipe, serious deformation of the air pipe and the like.
Example two
The second embodiment is substantially the same as the first embodiment, except that: with reference to fig. 1 to 3, the present embodiment further provides a novel tunnel construction ventilation system based on high-pressure air supply, and on the basis of the first embodiment, the ventilation system of the present embodiment further includes a secondary pressurization system, the secondary pressurization system includes an air booster pump third 3c disposed in the first high-pressure transportation section 4a and an air booster pump fourth 3d disposed in the second high-pressure transportation section 4b, the air booster pump third 3c is configured to re-pressurize the high-pressure fresh air 14 in the first high-pressure transportation section 4a, and the air booster pump fourth 3d is configured to re-pressurize the high-pressure fresh air 14 in the second high-pressure transportation section 4b, so that the secondary pressurization system is configured to perform secondary or multiple pressurization on the air flow entering the air flow transportation system; in order to avoid high-frequency arrangement of the supercharging equipment as much as possible, the limit distance of enough air quantity supplied to the tunnel face by single supercharging is taken as a node to carry out arrangement of the supercharging equipment for two times or multiple times, namely, the secondary supercharging equipment is additionally arranged to start supercharging when the air pressure of the first air-saving pipe is reduced to the initial air pressure; the ventilation system of the embodiment is an air multi-time pressurization system which is arranged according to the tunneling depth of the tunnel, the limit ventilation distance of the tunnel can be effectively prolonged, the starting number of the pressurization equipment is selected according to the actual situation, and the construction environment in the tunnel is effectively guaranteed on the premise of high efficiency and energy saving.
From above, this embodiment ventilation system includes the air supply driving system that supplies wind and pressurization in order to form high-speed air current, is used for carrying high-pressure air current's air current conveying system and carrying out the secondary supercharging system that wind current is secondary or impeld many times in the tunnel, and the concrete implementation mode is:
starting a first axial flow fan 1a, pumping fresh air 13 outside the parallel guide tunnel 5 into an air supply power system, enabling the fresh air 13 to enter a first air booster pump 3a along a first soft air pipe 2a, starting the first air booster pump 3a at the moment, enabling the fresh air 13 to pass through the first air booster pump 3a to form high-pressure fresh air 14, and pushing the high-pressure fresh air 14 into a first high-pressure transportation section 4 a;
starting an air booster pump III 3c, pressurizing the high-pressure fresh air 14 in the first high-pressure transportation section 4a for the second time, continuously pushing the high-pressure fresh air into the tunnel through the constant-diameter high-pressure hard air pipe A at a high speed by a larger dynamic pressure, and diffusing the high-pressure fresh air to the whole construction tunnel face A9 after passing through the gradually-changed-diameter high-pressure hard air pipe A of the first air flow diffusion section 4c to be replaced with polluted air 15 on the tunnel face A9; then the polluted air parallel to the tunnel face A9 of the pilot tunnel 5 is blown into the right-line tunnel entrance 8 of the tunnel by the jet fan 12 arranged in the auxiliary transverse channel 10 and is then guided to the right-line tunnel entrance 8 of the tunnel by the jet fan 12 arranged in the right-line tunnel entrance 8 of the tunnel; finally, the sewage is blown out of the tunnel to finish the pollution discharge of the tunnel face of the tunnel left line main tunnel or the parallel pilot tunnel 5;
starting the axial flow fan I1 a and simultaneously starting the axial flow fan II 1b, sucking fresh air 13 outside the parallel guide tunnel 5 into an air supply power system, enabling the fresh air 13 to enter an air booster pump II 3b along a soft air pipe II 2b, starting the air booster pump II 3b at the moment, enabling the fresh air 13 to form high-pressure fresh air 14 through the air booster pump II 3b, and pushing the high-pressure fresh air 14 into a second high-pressure transportation section 4b;
and (3) starting an air booster pump for four times, secondarily pressurizing high-pressure fresh air 14 in the second high-pressure transportation section 4B, continuously pushing the high-pressure fresh air into the tunnel through the equal-diameter high-pressure hard air pipe B at a high speed by a larger dynamic pressure, leading the high-pressure fresh air 14 into the tunnel auxiliary transverse channel 10 through the parallel guide tunnel 5 and then into the tunnel right-line positive tunnel inlet 8 through the guide of the equal-diameter high-pressure hard air pipe B, finally diffusing the high-pressure fresh air to the whole construction tunnel face B11 through the gradually-changed-diameter high-pressure hard air pipe B of the second air flow diffusion section 4d, replacing the high-pressure fresh air with the tunnel face polluted air 15, and leading the polluted air at the tunnel right-line positive tunnel inlet 8 to the tunnel right-line positive tunnel inlet 8 inlet by a jet fan 12 arranged in the tunnel right-line positive tunnel inlet 8 and finally blowing the polluted air out of the tunnel to finish the pollution discharge of the tunnel right-line positive tunnel inlet 8.
In the illustrated embodiment, the ventilation system of the present invention is a dynamic ventilation system, and as the tunnel excavation progresses, a new auxiliary transverse channel 10 is excavated near the tunnel face; the new auxiliary transverse passage 10 replaces the existing auxiliary transverse passage 10 to arrange the pipelines, and the original transverse passage is provided with a wind-blocking wall to prevent dirty wind from entering the hole; meanwhile, with the increase of the tunneling depth of the tunnel, the equal-diameter high-pressure hard air pipes 17 are continuously assembled, and the whole pipeline transportation system is lengthened, so that the tunnel face construction environments with different tunneling depths are ensured.
With reference to fig. 1 to 3, the present invention further provides a ventilation method using the novel tunnel construction ventilation system based on high-pressure air supply, including the following steps:
s1, analyzing a pollution source in a tunnel and determining a ventilation standard;
s2, designing a ventilation system;
s3, calculating ventilation parameters of the tunnel, and implementing a ventilation scheme;
the ventilation system in step S2 specifically includes: a wind power supply system is arranged at the inlet of the tunnel to form high-speed airflow; an airflow conveying system is adopted to convey high-pressure airflow in the tunnel, the airflow conveying system comprises a high-pressure conveying section formed by equal-diameter high-pressure hard air pipes 17 and an airflow diffusion section formed by at least one gradually-diameter high-pressure hard air pipe 19, a secondary pressurization system is additionally arranged in a first high-pressure conveying section 4a and a second high-pressure conveying section 4b, and a drain hole 25 is additionally arranged in a first airflow diffusion section 4c and a second airflow diffusion section 4d so as to form uniform dispersed airflow near the tunnel face;
the step S3 of calculating the tunnel ventilation parameters specifically includes: calculating the number and the arrangement distance of the air booster pumps in the secondary boosting system in the step S2; calculating the arrangement parameters of the drain holes 25 in the gas flow diffusion section;
wherein the air booster pump arrangement mode among the secondary supercharging system does: in order to avoid high-frequency arrangement change as much as possible, the arrangement of two/multiple times of supercharging equipment is carried out by taking the limit distance of enough air volume supplied to the tunnel face by single supercharging as a node, namely, secondary supercharging equipment is additionally arranged to start supercharging under the condition that the air pressure of the first section of equal-diameter high-pressure hard air pipe 17 is reduced to the initial air pressure, and the process is circulated.
Because the air is compressible gas, the air demand calculated according to relevant engineering parameters is the air quantity under the standard atmospheric pressure environment, and the density of the air is 1.225kg/m 3 Under the influence of the air booster pump, the full pressure of the system rises, the static pressure rises to cause the density state of the air in the pipeline to change, and the air density under the boosting state can be calculated according to an ideal gas equation:
ideal gas equation: PV = NRT, since n = M/M and ρ = M/V, the equation can also be written in two forms: PV = mRT and PM = ρ RT
Wherein: p is gas pressure (Pa); v is the gas volume (m) 3 ) N is the amount (mol) of the substance, R is the molar gas constant (J. Mol) -1 ·K -1 ) T is the absolute temperature (K), M is the mass (g) of the substance, M is the molar mass (g/mol) of the substance, which is numerically equal to the molecular weight of the substance, and ρ is the density (kg/M) of the gaseous substance 3 )。
Flow rate Q (m) 3 And/s) is a fluid volume per unit time, and the amount of compressible gas contained in a unit volume in a high-pressure state is actually different due to the difference in air density, and is converted by the following equation in order to ensure that construction ventilation can be supplied to a construction ventilation amount equal to the face per unit time:
Q 1 ρ 1 ＝Q 2 ρ 2 (1)
that is, the amount of air supplied to the space between the units is equal in the equal density state; wherein Q 1 Air quantity (m) required under standard atmospheric pressure for construction face 3 /s)；ρ 1 Is the density of air (kg/m) at standard atmospheric pressure 3 )； Q 2 The air quantity (m) required by the palm surface under high pressure 3 /s)；ρ 2 Is air density (kg/m) under high pressure 3 )。
Bringing into the ideal gas equation, then:
Figure SMS_3
according to the formula Q = vA, the wind speed in the pipe is:
Figure SMS_4
neglecting local resistance, and causing the pipeline system to increase suddenly along the way resistance due to the over-fast wind speed in the high-pressure pipe, wherein the friction resistance of the pipeline is the energy consumption generated by the friction between the wind flow and the peripheral wall of the ventilation pipe and the disturbance and friction among air molecules, and when the pipeline is not wind-tight, the along-way resistance is calculated according to the following formula:
Figure SMS_5
wherein h is f Is the frictional resistance (Pa) of the pipeline; λ is the coefficient of friction; l is the length of the pipeline (m); d is the pipe diameter (m); v is the wind speed in the pipeline (m/s); rho is air density (kg/m) 3 )。
To ensure that the system has sufficient wind pressure to overcome the on-way resistance, the initial pressure supply of the fan is assumed as follows: w is a group of p The supercharging multiple of the supercharging equipment is n, and the initial pressure in the pipe is nW p ；
Namely, the requirements are as follows:
Figure SMS_6
when the construction ventilation system provides static pressure along with the increase of the tunnel length and can not overcome the on-way resistance, the air demand of the tunnel face can not be satisfied any more, the left and right sides of the formula are equal, an equation about the pipeline length L is obtained, the maximum length of L can be obtained, the maximum length can be understood as the transportation of the length L after the booster pump is boosted, the pressure in the pipeline can not satisfy the requirement any more, and the booster equipment is added at the position and is timely boosted, namely:
Figure SMS_7
substituting the former formula (3) into the formula (6) to obtain:
Figure SMS_8
wherein: pi is the circumference ratio, and is taken as 3.14; m is the molar mass of the substance, the molar mass of air is equivalent to 29g/mol; rho 1 As the fluid density, the air density at room temperature of 20 ℃ and normal pressure of 1.205kg/m is taken 3 (ii) a R is a gas constant, and the air is 287J/(kg K); absolute temperature, 293K, from which:
Figure SMS_9
let the coefficient be K, then the equation can be written as:
Figure SMS_10
arrangement distance L of supercharging equipment, supercharging effect n (supercharging multiple) of the equipment, diameter d of pipeline and initial total pressure W of construction ventilation system p Is in direct proportion; the pressure boosting effect n of the equipment is related to the equipment in the actual engineering, and the value is 3-5; the value of the high-pressure hard air pipe is 0.4-0.6m; initial full pressure W of system p The system is provided by an axial flow fan and a jet flow fan which are arranged in an actual ventilation system; coefficient of friction lambda of pipelineSelecting a high-pressure air pipe material according to actual engineering; the air quantity Q required by the tunnel face is calculated according to the engineering conditions and related formulas in related industry specifications, and the arrangement distance L can be obtained.
Finally, the arrangement number N of the supercharging devices can be determined according to the arrangement distance of the devices and the actual ventilation distance D of the tunnel.
Finally, the arrangement distance L and the number N of the supercharging equipment of the high-pressure ventilation system are respectively obtained:
Figure SMS_11
wherein L is a device arrangement pitch (m); k is a formula correlation coefficient; n is the supercharging effect (multiple) of the supercharging equipment; d is the diameter (m) of the high-pressure air pipe; w p Providing initial wind pressure (Pa) for an axial flow fan of a ventilation system; lambda is the coefficient of friction of the pipeline, Q 1 Air quantity (m) required for construction face 3 (s), N is the number of equipment arrangements (stations); d is the ventilation length (m) of the tunnel, and all parameters can be obtained according to construction sites or design requirements.
In the embodiment, the ventilation length D =3000m and the tunnel face area S =10m in the construction of the small and medium-sized cross-section tunnel 2 The calculated air demand is 16.67m 3 The method comprises the following steps that/min, the diameter of a high-pressure hard air pipe is 0.6m, the high-pressure hard air pipe is made of PP (polypropylene) and all-plastic polypropylene, the friction coefficient lambda =0.2, a high-pressure axial flow fan arranged at a tunnel inlet provides initial air pressure of 2000Pa, the supercharging capacity of supercharging equipment is n =5, and the calculation is carried out according to the formula (10):
Figure SMS_12
in this example, the number of the two/more supercharging devices is 2, and the distance of the single device is 1119m.
In conclusion, the secondary supercharging system is designed according to the tunneling depth, the secondary supercharging system is arranged in the high-pressure transportation section, the number and the arrangement distance of the air supercharging pumps in the secondary supercharging system are obtained through accurate calculation, the limit ventilation distance of the tunnel can be effectively prolonged, the starting number of the supercharging equipment is selected according to actual conditions, the construction environment in the tunnel is effectively guaranteed on the premise of high efficiency and energy conservation, and the secondary supercharging system has high economic value; and the wind supply transportation mode of the novel ventilation system has wide application scenes, including but not limited to the use of the small-section tunnel scene, and the high-pressure wind flow wind supply technology can be effectively integrated with a plurality of traditional tunnel construction ventilation systems, so that a new thought is opened for ventilation design.
EXAMPLE III
The third embodiment is basically the same as the second embodiment, and the difference is that: with reference to fig. 1 to 3 and 5, in the present embodiment, a novel tunnel construction ventilation system based on high-pressure air supply is provided, on the basis of the second embodiment, the gradient-diameter high-pressure rigid air pipe 19 in the air flow diffusion section of the ventilation system of the present embodiment is provided with drain holes 25, in the illustrated embodiment, drain holes 25 are uniformly arranged on the outer contour surfaces of the gradient-diameter high-pressure rigid air pipe a and the gradient-diameter high-pressure rigid air pipe B, and are used for performing a diversion process on the terminal high-pressure air flow;
with reference to fig. 1 to 3 and 5, the present invention further provides a ventilation method using the novel tunnel construction ventilation system based on high-pressure air supply, including the following steps:
s1, analyzing a pollution source in a tunnel and determining a ventilation standard;
s2, designing a ventilation system;
s3, calculating ventilation parameters of the tunnel, and implementing a ventilation scheme;
the ventilation system in step S2 specifically includes: a wind power supply system is arranged at the inlet of the tunnel to form high-speed airflow; an airflow conveying system is adopted to convey high-pressure airflow in the tunnel, the airflow conveying system comprises a high-pressure conveying section consisting of a plurality of equal-diameter high-pressure hard air pipes 17 and an airflow diffusion section consisting of at least one gradually-reducing high-pressure hard air pipe 19, a secondary pressurization system is additionally arranged in the first high-pressure conveying section 4a and the second high-pressure conveying section 4b, and a drain hole 25 is additionally arranged in the first airflow diffusion section 4c and the second airflow diffusion section 4d to form uniform dispersed airflow near the tunnel face;
the step S3 of calculating the tunnel ventilation parameters specifically includes: calculating the number and the arrangement distance of the air booster pumps in the secondary boosting system in the step S2; calculating the arrangement parameters of the drain holes 25 in the gas flow diffusion section;
the arrangement mode of the gradual change high-pressure air duct drain holes 25 is as follows: according to the gas continuity law, the total air flow of the pipeline discharge hole 25 of the gradient-diameter high-pressure hard air pipe 19 and the pipeline outlet is the same as the air flow conveyed to the tunnel face by the equal-diameter high-pressure hard air pipe 17, in order to ensure that the fresh air 13 quantity can meet the requirements of construction ventilation, the equal-diameter high-pressure hard air pipe 17 is arranged near the tunnel face as much as possible, and the quantity and the area of the discharge port of the gradient-diameter pipe are designed by taking the outlet air speed and the discharge port air speed as references within the blasting smoke throwing distance range; as this embodiment is preferred, pipeline discharge hole 25 evenly arranges in the transition pipeline with circular, overflow from intraductal in order to ensure that high-pressure air current can follow the all-round, carry out reposition of redundant personnel to terminal high-pressure air current, can effectively reduce the interior air current pressure of pipeline, slow down the efflux wind speed, and can evenly carry fresh air to the face with the mode of filling, disperse dead angle in the tunnel, and effectively reduce the wind current pressure, when guaranteeing to provide the same amount of wind size in the unit interval, slow down transition wind speed relatively, avoid the return air too big.
Let N be the number of drain holes (N), and N be the drain hole area (m) 2 ) Based on the law of conservation of energy and continuity of gas, the formula is derived, and the detailed process is as follows:
according to the gas continuity equation, the mass of air flowing through each section per unit time should be equal, namely:
v 1 A 1 ρ 1 ＝v 1 A 1 ρ 1 (9)
the continuity equation for a transition can be written according to equation (9) as follows:
ρ a Q a ＝ρ 1 Q 1 +ρ 2 Q 2 +…+ρ n Q n +ρ b Q b (10)
wherein: ρ is a unit of a gradient a 、ρ b 、ρ n Are respectively a gradual change section inletGas density (kg/m) of outlet and discharge hole 3 )； Q a 、Q b 、Q c Air flow (m) of inlet, outlet and discharge hole of transition section 3 /s)
When incompressible constant fluid flows gradually in a pipeline, the pressure and the speed of the incompressible constant fluid change along each section of the flow path, and the incompressible constant fluid obeys the law of conservation of energy, also called Bernoulli's theorem, and the equation is as follows:
Figure SMS_13
air has viscosity, and internal friction force is generated when the air flows. Internal friction prevents air flow due to the influence of the layer of air adhering to the walls of the pipe (or tunnel), and energy is consumed to overcome the resistance caused by the internal friction and other reasons. The mechanical energy contained in the unit volume of air is reduced in the flowing process, so that the right end of the upper formula should be added with wind flow flowing from 1 section to 2 sections due to overcoming the resistance h L1-2 The consumed energy is changed into heat energy.
ρ v in the formula (3) 2 In the/2 term, v is the average wind speed of the section, and the kinetic energy calculated from the average wind speed is not equal to the kinetic energy calculated from the actual wind speed of the section, so the kinetic energy is multiplied by a coefficient K, and the value of the coefficient K depends on the roughness of the pipeline (or the tunnel) and the flow velocity distribution in the section. The proportion of the kinetic energy in the three energy in the tunnel ventilation is very small, and the value of the kinetic energy is small, so that the formula (11) is finally converted into a form suitable for tunnel engineering by taking K = 1:
Figure SMS_14
from equation (12), the bernoulli equation for the transition is written:
Figure SMS_15
two equations for calculating the parameters of the tapered section drain hole are obtained:
Figure SMS_16
neglecting the energy loss caused by overcoming the on-way resistance and the local resistance of the pipeline, assuming that the difference of the internal and external pressure of each drainage hole is equal, simplifying the formula:
Figure SMS_17
and (4) converting the form (14), and finally arranging the number and the area of the holes:
Figure SMS_18
substituting the ideal gas PM = ρ RT equation:
Figure SMS_19
wherein: n is the number of drain holes; c is the effect (times) of the supercharging equipment; w is a group of p Supplying wind pressure (Pa) to the fan; ρ is a unit of a gradient b 、ρ 1 Respectively the air density of the transition section outlet and the air density of the discharge hole outlet, and the air density is 1.205kg/m at the normal temperature of 20 ℃ and the normal pressure 3 (ii) a M is the molar mass of the substance, the molar mass of air is equivalent to 29g/mol; r is a gas constant, and the air is 287J/(kg K); t absolute temperature, taking 293K; v. of a The inlet air speed of the gradual change section; v. of b Is the transition section outlet wind speed; a. The b Is the outlet area (m) 2 ) According to A b ＝0.25×π× d b Calculating; q a Is the gradual change section wellhead flow (m) 3 And/s) according to the partial parameters, substituting (16) to obtain:
Figure SMS_20
substituting numerical values to obtain:
Figure SMS_21
finally, simplifying to obtain:
Figure SMS_22
wherein n is the number of drain holes; a. The 1 Is the area (m) of the discharge hole 2 ) (ii) a c is the supercharging multiple (times) of the supercharging equipment; w p Providing initial wind pressure (Pa) for an axial flow fan of a ventilation system; v. of 1 、v b Respectively the air speed (m/s) of an outlet of the drainage hole and an outlet of the gradual change section air pipe; q is the air quantity (m) required by the palm surface 3 /s)；d a 、d b The diameters (m) of an inlet and an outlet of the gradual change section air pipe are shown; k 1 、K 2 、K 3 、M 1 、M 2 The formula coefficients are respectively taken as follows: k 1 ＝1.66、 K 2 ＝17795.4、K 3 ＝1；M 1 ＝0.79、M 2 =1; the other parameters can be obtained according to the actual engineering or design requirements.
In the embodiment, the ventilation length D =3000m and the tunnel face area S =10m in the construction of the small and medium-sized cross-section tunnel 2 The calculated air demand is 16.67m 3 The method comprises the following steps of (1) calculating according to formula (1) that per min, the diameter of a high-pressure hard air pipe is 0.6m, the diameter of the final section of a gradual change section is 1.5m, the diameter is made of PP all-plastic polypropylene, a high-pressure axial flow fan is arranged at a tunnel inlet to provide initial air pressure of 2000Pa, supercharging equipment provides supercharging capacity of c =5, and the air speeds of an outlet of a 25-hole drain hole and an outlet of the gradual change section are both set to be 20 m/s:
Figure SMS_23
Figure SMS_24
then, the diameter d of the drain hole 25 Hole(s) =0.18m, 35 in total.
From the above, the ventilation system airflow diffusion section adopts the design of the vent holes 25, preferably, the circular vent holes 25 are uniformly arranged on the hard gradient-diameter high-pressure hard air pipe 19 near the tunnel face, the high-pressure airflow at the tail end of the drainage is subjected to flow division treatment, the airflow pressure in the pipeline can be effectively reduced, the jet flow wind speed is slowed down, fresh air can be uniformly conveyed to the tunnel face in a diffusion mode, the problems that other construction equipment is influenced by the excessive return air speed in the tunnel or local pollutants cannot be removed due to the fact that high-pressure columnar airflow cannot be diffused in time and the like are avoided, and the structural design is ingenious and reasonable.
The present specification and figures are to be regarded as illustrative rather than restrictive, and it is intended that all such alterations and modifications that fall within the true spirit and scope of the invention, and that all such modifications and variations are included within the scope of the invention as determined by the appended claims without the use of inventive faculty.

Claims (8)

1. The novel tunnel construction ventilation system based on high-pressure air supply comprises a tunnel right line main hole, an auxiliary transverse channel and a tunnel left line main hole or a parallel pilot tunnel, wherein the tunnel left line main hole or the parallel pilot tunnel is communicated with the tunnel right line main hole through the auxiliary transverse channel; the method is characterized in that: the ventilation system includes:
a wind power supply system arranged at a tunnel entrance to form a high velocity air stream;
the air flow conveying system is arranged in the tunnel and can extend to the inlet of the tunnel to be connected with the air supply power system, and is used for conveying high-pressure air flow into the tunnel;
the air flow conveying system comprises a high-pressure conveying section consisting of a plurality of equal-diameter high-pressure hard air pipes and an air flow diffusion section consisting of at least one gradually-changing diameter high-pressure hard air pipe, wherein the gradually-changing diameter high-pressure hard air pipe is arranged near a tunnel face operation section of the tunnel, so that high-speed air flow formed by the air supply power system can sequentially pass through the high-pressure conveying section and the air flow diffusion section to enter the vicinity of the tunnel face and form dispersive air flow;
the high-pressure transportation section comprises a first high-pressure transportation section and a second high-pressure transportation section which are respectively connected with the wind supply power system; the air flow diffusion section comprises a first air flow diffusion section communicated with the first high-pressure transportation section and a second air flow diffusion section communicated with the second high-pressure transportation section, and the first air flow diffusion section is arranged near a tunnel face A of a tunnel left-line main tunnel or a parallel pilot tunnel tunneled forwards; the second airflow diffusion section is arranged near a tunnel face B of the tunnel right-line forward tunnel;
first air current diffuser includes and extends to near the high-pressure tuber pipe A of gradual change footpath of face A by first high-pressure transportation section tip, and second air current diffuser includes and extends to near the high-pressure tuber pipe B of gradual change footpath of face B by second high-pressure transportation section tip, evenly arranged the discharge orifice on the outer profile face of the high-pressure tuber pipe A of gradual change footpath and the high-pressure tuber pipe B of gradual change footpath for carry out reposition of redundant personnel processing to terminal high-pressure draught.
2. The novel tunnel construction ventilation system based on high-pressure air supply of claim 1, characterized in that: the air supply power system comprises an axial flow fan and an air booster pump, the axial flow fan is connected with the air booster pump through a soft air pipe, and the air supply power system is arranged in the range of 10-20m outside the tunnel left line positive hole or the parallel pilot hole.
3. The novel tunnel construction ventilation system based on high-pressure air supply of claim 2, characterized in that: the axial flow fan comprises a first axial flow fan and a second axial flow fan, the air booster pump comprises a first air booster pump and a second air booster pump, an air inlet of the first air booster pump is connected with the first axial flow fan through a first soft air pipe, and an air supply end of the first air booster pump is communicated with the first high-pressure transportation section; and an air inlet of the air booster pump II is connected with the axial flow fan II through a soft air pipe II, and an air supply end of the air booster pump II is communicated with the second high-pressure transportation section.
4. The novel tunnel construction ventilation system based on high-pressure air supply of claim 2, characterized in that: the air booster pump is single-air-source boosting equipment and can improve the air pressure of the air supply system by 3-5 times.
5. The novel tunnel construction ventilation system based on high-pressure air supply of claim 1, characterized in that: the first high-pressure transportation section comprises a plurality of equal-diameter high-pressure hard air pipes A which are sequentially spliced and connected, the second high-pressure transportation section comprises a plurality of equal-diameter high-pressure hard air pipes B which are sequentially spliced and connected, and the diameters of the equal-diameter high-pressure hard air pipes A and the equal-diameter high-pressure hard air pipes B are 0.4-0.6m.
6. The novel tunnel construction ventilation system based on high-pressure air supply of claim 1, characterized in that: the equal-diameter high-pressure hard air pipes and the gradient-diameter high-pressure hard air pipes are made of one or more of PVC, galvanized iron sheet, PP (polypropylene), all-plastic polypropylene and steel lining plastic.
7. The novel tunnel construction ventilation system based on high-pressure air supply of any one of claims 1 to 6, characterized in that: the ventilation system is still including the secondary supercharging system, the secondary supercharging system including arrange in air booster pump three in the first high pressure transportation section and arrange in air booster pump four in the second high pressure transportation section, the secondary supercharging system is used for carrying out secondary or pressurization many times to the air current that gets into in the air current conveying system.
8. The ventilation method of the novel tunnel construction ventilation system based on the high-pressure air supply of any one of claims 1 to 7 is adopted, and comprises the following steps:
s1, analyzing a pollution source in a tunnel and determining a ventilation standard;
s2, designing a ventilation system;
s3, calculating ventilation parameters of the tunnel, and implementing a ventilation scheme;
the method is characterized in that:
the ventilation system in step S2 specifically includes: a wind power supply system is arranged at the inlet of the tunnel to form high-speed airflow; an airflow conveying system is adopted to convey high-pressure airflow in the tunnel, the airflow conveying system comprises a high-pressure conveying section consisting of a plurality of equal-diameter high-pressure hard air pipes and an airflow diffusion section consisting of at least one gradually-variable-diameter high-pressure hard air pipe, a secondary pressurization system is additionally arranged in the high-pressure conveying section, and a drainage hole is additionally arranged in the airflow diffusion section to form uniform dispersed airflow near the tunnel face;
the step S3 of calculating the tunnel ventilation parameters specifically includes: calculating the number and the arrangement distance of the air booster pumps in the secondary boosting system in the step S2; and calculating the arrangement parameters of the drain holes in the airflow diffusion section.
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