Tunnel ventilation construction method

Abstract

This invention provides a tunnel ventilation construction method, belonging to the field of tunnel engineering. It includes: ventilation of the entrance work area and cross passage work area, using a single-machine, single-pipe forced-in method to inject fresh air into the excavation face; ventilation after tunnel breakthrough, utilizing cross passages for tunnel ventilation; and tunnel dust control, implementing dust control throughout the entire tunnel excavation stage. The aim is to solve the problems of turbulent airflow and insufficient air supply that are common in existing tunnel ventilation construction methods. The achieved technical effects are: avoiding localized oxygen deficiency and harmful gas accumulation caused by turbulent airflow, and significantly improving the air circulation and safety of the working face during tunnel ventilation construction.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering technology, and in particular to a tunnel ventilation construction method. Background Technology

[0002] When tunnel engineering traverses complex geological conditions, environmental control remains crucial for ensuring both safety and efficiency. Current tunnel ventilation technologies have several shortcomings. During the parallel construction phase of the entrance and cross-tunnel areas, traditional ventilation methods suffer from chaotic airflow paths due to the complex tunnel structure and narrow working space. Fresh air often fails to reach the excavation face effectively due to short-circuiting effects, resulting in insufficient oxygen content and excessive concentrations of harmful gases such as methane at the working face, posing a risk of suffocation and poisoning to construction workers. Once the tunnel is completed, the ventilation requirements of long-distance, single-channel systems become unsustainable using traditional single-forced or single-exhaust ventilation models. As the tunnel extends, ventilation resistance increases dramatically, causing the energy consumption of traditional single-forced or single-exhaust ventilation fans to rise exponentially, while failing to achieve airflow circulation throughout the entire tunnel. This leads to significant problems with the retention of harmful gases in deep areas, potentially even causing major accidents such as explosions due to accumulated concentrations.

[0003] In summary, existing ventilation technologies are insufficient to effectively deliver fresh air to each excavation face, and are prone to problems such as turbulent airflow and insufficient supply. After the tunnel is completed, long-distance ventilation faces the dilemma of high resistance and inefficient airflow circulation. Summary of the Invention

[0004] This invention provides a tunnel ventilation construction method to solve the defects of existing tunnel ventilation construction methods, which are prone to airflow turbulence and insufficient supply. This method avoids local hypoxia and harmful gas accumulation caused by airflow turbulence, and significantly improves the working environment at the tunnel face, as well as the air circulation and safety after tunnel breakthrough.

[0005] This invention provides a tunnel ventilation construction method, comprising: For ventilation in the import work area and the cross tunnel work area, fresh air is injected into the excavation face using a single-machine, single-pipe forced-in method. Ventilation is carried out after the tunnel is completed. The method of using cross passages for tunnel ventilation is used to ventilate the tunnel. Dust control measures are implemented throughout the entire tunnel excavation process.

[0006] In addition, the tunnel ventilation construction method according to the present invention may also have the following additional technical features: In some embodiments of the present invention, ventilation of the inlet work area and the cross tunnel work area, using a single-machine, single-pipe forced-in method to inject fresh air into the excavation face, includes: For ventilation in the entry work area, a forced-flow axial fan with flexible duct is installed at the tunnel entrance to inject fresh air into the excavation face using a single-unit, single-duct forced-flow method. Ventilation in the early and later stages of construction in the transverse tunnel area is achieved by installing a single forced-flow axial fan with flexible duct at the tunnel entrance to inject fresh air into the corresponding excavation face. During the mid-term ventilation of the cross tunnel construction area, at least two forced-flow axial flow fans are arranged at the entrance of the cross tunnel. Each forced-flow axial flow fan is equipped with a flexible air duct. Fresh air is injected into the main tunnel at both the large and small mileage excavation faces through a single-unit, single-duct forced-flow method.

[0007] In some embodiments of the present invention, the arrangement method of the forced-flow axial fan includes: Install the forced-flow axial fan and silencer according to the drawings; After installation quality inspection and trial operation, the painting process will begin.

[0008] In some embodiments of the present invention, the installation method of the forced-flow axial flow fan includes: Civil engineering construction, including the construction of civil engineering foundation structures; The forced-flow axial flow fan is installed on the civil engineering foundation; Diffuser and duct installation: Install the diffuser at the outlet of the forced axial flow fan and connect the duct to the diffuser.

[0009] In some embodiments of the present invention, the method of installing the muffler includes: The upper and lower silencers are installed between the silencers and connected by connectors to form a silencer. The silencer is installed between the casing of the forced axial flow fan and the casing, with silencers installed on the top and bottom plates of the casing respectively; The casing is installed between the casing and the forced axial flow fan, with the forced axial flow fan installed inside the casing.

[0010] In some embodiments of the present invention, before arranging the forced axial flow fan, two power supplies are installed in the tunnel, both of which are electrically connected to the forced axial flow fan.

[0011] In some embodiments of the present invention, the installation method of the flexible duct includes: Mark the position of the expansion screws and install them; Arrange the guy wires, place them on the expansion bolts, and use a tensioner to straighten and fix them; For flexible duct installation, a hanging ring is placed on the pull line at each first preset distance, and the flexible duct is inserted into the hanging ring.

[0012] In some embodiments of the present invention, after the flexible duct is arranged, a reflective sticker is arranged on the flexible duct at second preset intervals.

[0013] In some embodiments of the present invention, the method of using a cross passage for tunnel ventilation includes: At least one explosion-proof exhaust axial flow fan is installed at the entrance and exit of the main tunnel. The cross passage is used for tunnel ventilation. Fresh air enters from the cross passage and is extracted from the entrance and exit of the main tunnel, forming a circulating airflow.

[0014] In some embodiments of the present invention, the method for tunnel dust control includes: For ventilation and dust prevention, the flexible air duct is suspended on one side of the tunnel and made parallel to the tunnel. Wet drilling is carried out using a drilling and rock-drilling frame; the tunneling face is washed before blasting and muck removal. For dust suppression, wet spraying is used throughout the tunnel.

[0015] In summary, this application includes the following beneficial technical effects: by setting up different ventilation methods for the inlet work area, the cross tunnel work area, and the ventilation after tunnel breakthrough, a phased ventilation technology and a full-process dust control system are constructed, breaking through the technical bottleneck of environmental control in traditional tunnel construction; during the construction phase of the inlet work area and the cross tunnel work area, the single-unit single-pipe forced ventilation with directional air supply mode accurately solves the problem of blind spots in fresh air delivery in traditional multi-face ventilation, avoids local hypoxia and harmful gas accumulation caused by airflow turbulence, and significantly improves the air circulation and safety of the working environment at the working face.

[0016] After the tunnel is completed, the tunnel ventilation system utilizes the space between the cross passages and the main tunnel to form a composite airflow system with natural air ducts and fan assistance. This effectively overcomes the shortcomings of traditional long-distance single-pipe ventilation, such as high resistance, high energy consumption, and uneven air exchange. By adjusting the ventilation system and optimizing the fan layout and airflow organization in the tunnel, uniform ventilation is achieved throughout the entire tunnel, significantly reducing the risk of methane and other harmful gases accumulating and providing a continuous and stable air quality guarantee for subsequent lining, equipment installation, and other operations. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic flowchart of a tunnel ventilation construction method according to some embodiments of the present invention is shown.

[0018] Figure 2 A flowchart illustrating the arrangement of a forced axial flow fan in a tunnel ventilation construction method according to some embodiments of the present invention is shown.

[0019] Figure 3 A flowchart illustrating the installation method of a forced-flow axial flow fan in a tunnel ventilation construction method according to some embodiments of the present invention is shown.

[0020] Figure 4 A flowchart illustrating a silencer installation method in a tunnel ventilation construction method according to some embodiments of the present invention is shown.

[0021] Figure 5 A schematic diagram illustrating the initial ventilation stage of a tunnel ventilation construction method according to some embodiments of the present invention is shown.

[0022] Figure 6 A schematic diagram illustrating mid-term ventilation during tunnel construction in a cross passage area according to some embodiments of the present invention is shown.

[0023] Figure 7 A schematic diagram illustrating the ventilation in the later stage of tunnel construction in a cross passage area according to some embodiments of the present invention is shown.

[0024] Figure 8 A schematic diagram of ventilation after tunnel breakthrough is shown in a tunnel ventilation construction method according to some embodiments of the present invention.

[0025] Figure label: 1. Forced axial flow fan, 2. Flexible duct, 3. Horizontal opening, 4. Tunnel inlet, 5. Exhaust axial flow fan. Detailed Implementation

[0026] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0027] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” used herein may also refer to the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a specific order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0028] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0029] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "upper," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0030] like Figures 1 to 8 As shown, according to an embodiment of the first aspect of the present invention, a tunnel ventilation construction method is proposed, comprising: For ventilation in the import work area and the cross tunnel work area, fresh air is injected into the excavation face using a single machine and single pipe forced injection method. Ventilation is carried out after the tunnel is completed. The method of using cross passages for tunnel ventilation is used to ventilate the tunnel. Dust control measures are implemented throughout the entire tunnel excavation process.

[0031] In the above embodiments, it should be noted that the single-unit single-pipe forced-in method includes connecting a single ventilation duct to a single ventilator to force fresh air from the outside into the working area of ​​the tunnel excavation face, forcing the polluted air to be discharged through the natural passage, i.e., the tunnel body, thereby achieving air circulation; the ventilator can be a forced-in axial flow fan 1.

[0032] The specific working principle includes the pressing process and the sewage discharge process: The pressurization process involves the following steps: after the ventilation fan is started, fresh outside air is pressurized by the fan and enters the flexible air duct, which is then transported along the duct to the vicinity of the work area to dilute the dust, harmful gases, and heat in that area.

[0033] The sewage discharge process involves the polluted air being pushed out through the tunnel by fresh air, forming a cycle of fresh air being forced in to replace the polluted air and then being discharged naturally.

[0034] The technical effects achieved by the above embodiments are as follows: by setting up different ventilation methods for the ventilation of the entrance work area and the cross tunnel work area and the ventilation after the tunnel breakthrough, a phased ventilation technology and a whole-process dust control system are realized, breaking through the technical bottleneck of environmental control in traditional tunnel construction; during the construction phase of the entrance work area and the cross tunnel work area, the single-unit single-pipe forced ventilation with directional air supply mode accurately solves the problem of blind spots in fresh air delivery in traditional multi-face ventilation, avoids local hypoxia and harmful gas accumulation caused by airflow turbulence, and significantly improves the air circulation and safety of the working environment at the working face.

[0035] After the tunnel is completed, the tunnel ventilation system utilizes the space to form a composite airflow system of natural air ducts and fan assistance, which effectively overcomes the defects of traditional long-distance single-pipe ventilation, such as high resistance, high energy consumption and uneven air exchange. By optimizing the fan layout and tunnel airflow organization, uniform ventilation is achieved throughout the entire tunnel, which greatly reduces the risk of methane and other harmful gases accumulating and provides a continuous and stable air quality guarantee for subsequent lining, equipment installation and other operations.

[0036] Optional, such as Figure 1 and Figures 5 to 7 As shown, the ventilation methods for the inlet work area and the cross tunnel work area, which use a single-machine, single-pipe forced-in method to inject fresh air into the excavation face, include: At the entrance work area, a forced axial flow fan 1 with a flexible air duct 2 is installed at the tunnel entrance 4 to inject fresh air into the excavation face using a single-unit, single-duct forced injection method. In the early and late stages of construction in the cross tunnel area, a single-unit axial flow fan 1 with a flexible air duct 2 is installed at the cross tunnel entrance 3 to inject fresh air into the corresponding excavation face. During the middle stage of construction in the transverse tunnel area, at least two forced-flow axial flow fans 1 are arranged at the tunnel entrance. Each forced-flow axial flow fan 1 is equipped with a flexible air duct 2. Fresh air is injected into the main tunnel at both the large and small mileage excavation faces by a single machine and a single duct.

[0037] In the above optional embodiments, it should be noted that, in the inlet work area, the diameter of the flexible air duct 2 on the forced axial flow fan 1 arranged at the tunnel inlet 4 is 2 meters; the diameter of the flexible air duct 2 connected to the forced axial flow fan 1 in the early stage of construction in the cross tunnel work area, in the middle stage of construction in the cross tunnel work area, and at the end of construction is 1.8 meters.

[0038] Specifically, when the construction of the transverse tunnel begins in the early stage of the transverse tunnel construction, a forced axial flow fan 1 is arranged on the right side of the transverse tunnel entrance 3, and a φ1.8m flexible air duct 2 is configured to carry out single-unit single-duct forced ventilation. Fresh air enters the excavation face through the fan and flexible air duct 2, while polluted air is discharged outside the tunnel along the tunnel body.

[0039] During the middle stage of construction in the transverse tunnel area, when the main tunnel is being constructed at both the large and small mileage levels, two forced-flow axial flow fans 1 are arranged on the left and right sides of the tunnel entrance, equipped with φ1.8m flexible air ducts 2, to carry out single-unit, single-pipe forced ventilation. Fresh air enters the large and small mileage excavation faces through the axial flow fan 1 and flexible air duct 2 respectively, while polluted air is discharged outside the tunnel along the tunnel body.

[0040] In the later stage of the construction of the transverse tunnel area, after the completion of the large-mileage construction of the transverse tunnel area, a forced-flow axial fan 1 is arranged on the right side of the tunnel entrance, and a φ1.8m flexible air duct 2 is configured to carry out single-unit single-duct forced ventilation. Fresh air enters the large-mileage and small-mileage excavation faces through the forced-flow axial fan 1 and the flexible air duct 2 respectively, while the polluted air is discharged outside the tunnel along the tunnel body.

[0041] Optionally, the arrangement of the forced axial flow fan 1 and flexible duct 2 in the inlet work area may include the following methods: A liftable fan base using hydraulic lifting is installed at tunnel entrance 4. The specific lifting method can be achieved using existing hydraulic lifting structures, which will not be discussed in detail here. A forced-flow axial fan 1 is mounted on the fan base.

[0042] The flexible air duct 2 uses a double-helix steel ring frame with an anti-static coating on the outer perimeter of the frame. It has a diameter of 2 meters and is suspended along the tunnel sidewall in a catenary shape. An elastic sling is installed every 10 meters to buffer the vibration of the flexible air duct 2.

[0043] In the early stages of construction in the transverse tunnel area, a forced-flow axial fan 1 was installed at the tunnel entrance 3, along with a flexible duct 2 with a diameter of 1.8 meters. The flexible duct 2 was arranged in a "zigzag" or "serpentine" manner: the flexible duct 2 was bent 30° towards the side wall every 10 meters, and the airflow was used to impact the tunnel wall to form a scattered airflow, which solved the problem of dead zones in the middle area caused by the wall-hugging airflow in the small cross-section tunnel, thereby increasing the wind speed at the working face.

[0044] During the middle stage of construction in the transverse tunnel area, the two forced-flow axial fans 1 were staggered in their start-up time by using a time-difference start-up controller to avoid overload of the starting current. At the same time, a pressure balancing valve was installed between the two flexible air ducts 2 to prevent air volume reduction caused by mutual interference.

[0045] In the later stages of construction in the transverse tunnel area, detachable rigid supports are used to fix the flexible air duct 2, and adjacent sections of the flexible air duct 2 are connected by flanges, reducing the frequency of manual connection of the flexible air duct 2. It should be noted that the detachable rigid supports can be the existing forced-in axial flow fan 1 support.

[0046] In addition, the interface of the flexible air duct 2 is equipped with double reverse edges and nylon zippers to achieve sealing, and the outer perimeter is tightened with steel bands, and the air leakage rate is controlled within 5%; when crossing the intersection of the cross tunnel and the main tunnel, rubber flexible joints are installed to adapt to the pipe deformation caused by uneven settlement of the tunnel.

[0047] In addition, fluorescent wind pressure test strips are pasted every 10 to 20 meters along the flexible air duct 2. The color change visually indicates the pressure status inside the duct. When the test strip turns yellow, indicating low pressure, the front section of the flexible air duct 2 should be checked for bends or damage.

[0048] The beneficial effects of the above optional embodiments are as follows: by setting a single forced axial flow fan 1 with a flexible air duct 2 in the directional air supply mode in the inlet work area, the working area of ​​the working face can be accurately covered, avoiding the airflow collision and energy loss caused by traditional multi-machine decentralized ventilation, ensuring that fresh air reaches the excavation face at a stable flow rate, quickly diluting harmful gases such as carbon monoxide and nitrogen oxides generated after blasting, shortening the ventilation cycle time, and improving the working efficiency of a single work area.

[0049] In the early and later stages of construction in the cross-tunnel area, the single-unit, single-pipe configuration of a single fan at the tunnel entrance can flexibly adapt to the ventilation needs of small-section tunnels. Through the flexible extension of the flexible air duct 2, the air supply distance can be dynamically adjusted according to the excavation progress, avoiding the cumbersome procedures of rigid pipe installation. This reduces equipment relocation costs while ensuring ventilation effects, and is especially suitable for the cross-tunnel expansion stage where the construction site is limited.

[0050] During the mid-term construction, at least two forced-flow axial fans were deployed at the tunnel entrance to achieve a multi-fan collaborative operation mode. This enabled point-to-point air supply to different excavation faces in the complex working conditions of simultaneous excavation at multiple working faces in the transverse tunnel area, through an independent air supply system with separate fans and pipes. This broke through the bottleneck of the limited coverage of traditional single fans and avoided the problem of insufficient air pressure at the end due to excessively long single pipes. It ensured that each working face could obtain sufficient fresh air, effectively solved the problem of poor ventilation when multiple working faces were constructed in parallel, and provided a reliable environmental guarantee for the efficient excavation of the transverse tunnel area.

[0051] Optional, such as Figures 2 to 4 As shown, the arrangement method of the forced axial flow fan 1 includes: Install the forced axial flow fan 1 and the silencer according to the drawings; After installation quality inspection and trial operation, the painting process will begin.

[0052] In the above optional embodiments, it should be noted that the installation quality inspection includes checking whether the forced axial flow fan 1 is installed stably; checking whether the various parts of the silencer are tightly assembled and fitted, whether the mating surfaces are coated with sealant, and whether there is any air leakage; checking the flatness of the silencer's outer surface, and whether there are any obvious dents, scratches, or corrosion; checking whether the direction of the silencer and the forced axial flow fan 1 is correct, and whether there is any damage or moisture; ensuring that all sound-absorbing and silencing materials inside the silencer are filled firmly, of uniform thickness, without gaps, and without falling off; and tightening the silencer. The screws of the silencer components are evenly distributed, the joints are flat, and there is no loosening or falling off; the perforated plate is flat, the holes are evenly arranged, there are no sharp corners or burrs, the surface of the perforated plate is clean, and there is no dirt or rust. The thickness of the perforated material is ≥1mm, the perforation rate is ≥30%, and the holes are smooth and evenly arranged; the paint on the silencer is flat and beautiful, without defects such as leakage, bubbling, wrinkles, or peeling; each longitudinal section is parallel to each other, the outer end of the front edge of the silencer is in the same plane perpendicular to the airflow direction, and it is firmly connected to the intermediate connecting plate.

[0053] The trial run includes testing the forced axial flow fan 1, which should follow the procedure of first manually testing and then automatically running. The automatic running includes jogging and continuous operation of the forced axial flow fan 1. Then, the fan performance is tested. If everything is normal, the trial run ends.

[0054] After the single-unit trial operation of the forced axial flow fan 1 is successful, the forced axial flow fan 1 and the silencer are painted to ensure aesthetic performance.

[0055] The advantages of the above-mentioned optional embodiments are as follows: Precise positioning and installation of the forced-flow axial fan 1 and silencer using drawings ensures that the equipment layout meets ventilation design parameters, avoiding airflow short-circuiting or insufficient local air pressure due to positional deviations, thus guaranteeing the scientific nature and stability of the air supply system from the source. During the quality inspection process, the solidity of the fan foundation and the sealing of the silencer connection are verified item by item, effectively eliminating potential equipment operation hazards and reducing the risk of failure during construction. The trial operation process involves simulating actual working conditions through ventilation tests, adjusting parameters such as fan direction and wind speed in real time to ensure that equipment performance precisely matches the ventilation needs of the work area, avoiding energy waste caused by insufficient or excessive airflow.

[0056] The application of coating technology not only gives equipment anti-corrosion and anti-rust functions and extends its service life in outdoor environments, but also enhances the standardized image of the construction site through color identification, which facilitates the later maintenance and management of equipment.

[0057] Optional, such as Figures 2 to 4 As shown, the installation method of the forced-flow axial fan 1 includes: Civil engineering construction, including the construction of civil engineering foundation structures; Installation of the forced axial flow fan 1: Install the forced axial flow fan 1 on the civil engineering foundation; Diffuser and duct installation: Install the diffuser at the outlet of the forced axial flow fan 1 and connect the duct to the diffuser.

[0058] In the above optional embodiments, it should be noted that the construction of the civil engineering foundation structure includes the following steps in the following order: positioning, setting out, excavation, laying the foundation layer, formwork erection and binding, concrete pouring, surface finishing, formwork removal, backfilling, setting out the elevation line and center line.

[0059] Specifically, positioning and setting out can determine the accurate location of the foundation in the tunnel space, providing a measurement benchmark for subsequent construction.

[0060] Positioning and layout work can be carried out using a total station or laser guide.

[0061] Excavation, or earthwork excavation, can create a foundation working surface to excavate a foundation pit according to the design elevation and dimensions, thus creating space for foundation construction.

[0062] The foundation layer is a concrete foundation layer that is poured to form a uniform and stable leveling layer at the bottom of the foundation pit, which facilitates subsequent formwork and reinforcement positioning, while protecting the foundation soil.

[0063] Formwork support and rebar tying are the process of supporting the formwork and tying the rebars to construct the foundation framework.

[0064] Formwork support can fix the shape, size and position of the foundation and withstand the lateral pressure during concrete pouring.

[0065] Rebar tying can enhance the foundation's bearing capacity and crack resistance through the rebar cage.

[0066] Concrete pouring, also known as concrete pouring, is the process of filling the space between steel bars and formwork into a dense concrete structure.

[0067] Surface finishing, also known as polishing, is used to smooth concrete surfaces, ensuring a flat top surface for easy installation of the forced-flow axial fan 1 and silencer.

[0068] Demolding means removing the formwork to expose the foundation structure while avoiding damage to the concrete surface.

[0069] Backfilling refers to backfilling the foundation pit around the foundation to restore the integrity of the surrounding rock or soil of the tunnel, transfer loads, and prevent lateral soil deformation.

[0070] Marking elevation lines and center lines involves marking the elevation and axis on the foundation surface, providing a precise basis for the installation of the forced axial flow fan 1 and the silencer.

[0071] In addition, the method of connecting the air duct and the diffuser is to use an electric trolley or chain hoist to lift the diffuser and the air duct, fabricate a support column on site, and then connect the diffuser to the fan with bolts through the flange, and seal the joint surface with a 4mm thick rubber strip.

[0072] After the forced-flow axial fan 1 is installed, the air valve is installed on the air duct by using a chain hoist and an electric trolley inside the fan room for transport and hoisting.

[0073] The installation of the forced-flow axial fan 1 also includes the following methods: Acceptance of the foundation: Check the dimensions, elevation, and strength of the civil engineering foundation to provide a qualified support surface for the installation of the forced axial flow fan 1.

[0074] Install shims to transfer equipment loads to the foundation, and also to fine-tune the elevation, levelness, and verticality of the fan.

[0075] Once the equipment is in place, hoist the main unit and motor of the forced axial flow fan 1 above the foundation, positioning them on the top surface of the shim set, and initially align them with the installation reference line.

[0076] Initial leveling and alignment are performed by adjusting the height and position of the shims to ensure the fan meets the initial requirements for horizontality, verticality, and coaxiality.

[0077] One grouting process involves pouring fine aggregate concrete around the anchor bolt holes and shim groups to initially fix the fan base to the foundation.

[0078] Secondary grouting involves grouting the gap between the base and the top surface of the foundation after the fan has been finally leveled and aligned, forming an integral load-bearing structure.

[0079] Optionally, the following method can also be adopted for the layout of the forced axial flow fan 1: use an assembled steel structure base to replace the traditional concrete foundation. The base is composed of an H-shaped steel frame and spring shock absorbers: Weld leveling jacks at the bottom of the frame, and adjust the base elevation in real time through a laser level for calibration; The spring shock absorbers adopt shock absorbers with upper and lower double damping layers. The upper rubber pad absorbs high-frequency vibrations, and the lower steel spring attenuates low-frequency swaying to reduce the vibration transmission rate of the fan.

[0080] Then, pre-assemble the forced axial flow fan 1 and the muffler: adopt the method of quick flange connection, pre-install the bolts at the outlet of the forced axial flow fan 1 and the inlet of the muffler in the factory, and use a chain hoist for integral hoisting in the tunnel to shorten the hoisting time.

[0081] Set a double-sealing ring structure at the connection between the inlet and outlet of the forced axial flow fan 1 and the flexible air duct 2: the inner layer is a silicone rubber sealing ring, and the outer layer adopts an inflatable sealing capsule. The sealing state is monitored in real time through a pressure gauge. After installation, conduct a smoke leakage test: inject smoke agent into the flexible air duct 2, apply soap water at the interface, and it is qualified if there are no bubbles within 5 minutes.

[0082] Then, paste a thermal imaging identification patch on the shell of the forced axial flow fan 1. The patch shows different colors with temperature changes: green < 40°C, yellow 40 - 60°C, red > 60°C.

[0083] During the commissioning stage, use a stethoscope-type vibration detector to collect vibration data at 5 measurement points such as the bearing housing and the motor end cover, and draw a curve between the rotational speed and the vibration amplitude. If the vibration value in a certain frequency band exceeds the ISO1940 standard G6.3 level, stop the machine immediately for adjustment.

[0084] The painting method includes a primer, spraying an epoxy zinc-rich paint to provide cathodic protection; an intermediate paint, brushing a micaceous iron oxide epoxy intermediate paint to form a flaky shielding layer to resist salt spray corrosion; a topcoat, selecting a polyurethane acrylic topcoat and adding a nano-titanium dioxide anti-aging agent, with a weather resistance of more than 10 years, and at the same time having hydrophobicity to reduce dust adhesion.

[0085] Adopt an orange and white alternating warning color on the shell of the forced axial flow fan 1 to improve the recognition of construction personnel. Spray reflective guiding arrows on the surface of the muffler, and the arrows point to the air flow direction. At night, form a reflective guide through the tunnel lighting to assist in the inspection of the ventilation system.

[0086] The advantages of the above-mentioned optional embodiments are as follows: In the civil construction phase, the civil foundation structure provides a solid bearing platform for the forced-flow axial fan 1. By accurately controlling the elevation and flatness of the foundation, the fan can be ensured to operate smoothly after installation, avoiding problems such as equipment vibration and excessive noise caused by foundation settlement or structural deviations, thus ensuring the long-term reliability of the ventilation system from a hardware perspective.

[0087] The forced-flow axial flow fan 1, installed on the civil engineering foundation, further enhances the equipment's impact resistance, making it particularly suitable for complex conditions such as blasting vibrations and mechanical operations during tunnel construction. This effectively reduces the risk of displacement of the forced-flow axial flow fan 1, ensuring the continuity and stability of air supply. The modular installation of the diffuser and duct optimizes the airflow transition structure at the outlet of the forced-flow axial flow fan 1, uniformly guiding the high-speed airflow generated by the fan into the duct, avoiding energy loss and noise surges caused by sudden airflow changes. The diffuser's guiding effect reduces airflow eddies, allowing fresh air to be delivered to the excavation face with more stable air pressure and a more uniform flow rate, improving ventilation efficiency while reducing pipeline losses.

[0088] Optional, such as Figure 4 As shown, the methods for installing the muffler include: The upper and lower silencers are installed between the silencers and connected by connectors to form a silencer. The silencer is installed between the casing of the forced axial flow fan 1 and the casing. The silencer is installed on the top plate and bottom plate of the casing respectively. The housing is installed between the housing and the forced axial flow fan 1, with the forced axial flow fan 1 installed inside the housing.

[0089] In the above optional embodiments, it should be noted that the muffler is a plate-shaped muffler with two muffler plates.

[0090] During the installation of the sound-absorbing plates, in order to ensure convenient underground installation between the sound-absorbing plate modules, connection holes are drilled on the bottom plate of the front edge of the sound-absorbing plate. After the upper and lower sound-absorbing plates are stacked by connectors, they are then connected and fixed with clamps and bolts.

[0091] In the connection between the silencer plate and the housing of the forced axial flow fan 1, the silencer is positioned on the top and bottom plates of the housing, and the top and bottom silencer plates are embedded between the two silencer plates of each silencer. The entire installation is accurate and compact.

[0092] Optionally, the installation of the muffler can include the following methods: a three-stage stepped sealing structure is set between the contact surfaces of the two mufflers: the first stage uses a silicone elastic sealing strip, the second stage arranges a labyrinth aerogel sound insulation layer, and the last stage embeds a metal corrugated compensation sheet to form a triple acoustic sealing system to ensure the sealing and sound insulation effect.

[0093] The advantages of the above-mentioned optional embodiments are as follows: During the installation of the sound-absorbing plates, the upper and lower sound-absorbing plates are rigidly connected by connectors, which allows for precise control of the spacing and parallelism between the plates, forming a regular sound wave channel. This structural design enables the sound waves to generate frictional loss in the porous sound-absorbing material of the sound-absorbing plates when the airflow passes through, effectively reducing the high-frequency aerodynamic noise of the forced-flow axial fan 1 during operation, avoiding the noise reduction performance attenuation caused by installation errors in traditional sound-absorbing structures, and creating a low-noise working environment for construction personnel.

[0094] The integrated installation of the silencer plates and the housing forms a closed acoustic cavity by fixing the silencer plate assembly to the top and bottom plates of the housing. This structure not only enhances the overall rigidity of the silencer, enabling it to withstand vibration loads during tunnel construction, but also expands the sound wave reflection and absorption path through the synergistic effect of the housing and the silencer plates, achieving a combined noise reduction effect on mid- and low-frequency noise. The forced-flow axial fan 1 is installed within the housing, achieving seamless connection between the silencer module and the ventilation equipment, avoiding the airflow leakage problem of traditional external silencers, and ensuring that the noise reduction process does not affect the fan's airflow and air pressure output efficiency.

[0095] Optional, such as Figure 1 As shown, before installing the forced axial flow fan 1, two power supplies are installed in the tunnel, and both power supplies are electrically connected to the forced axial flow fan 1.

[0096] In the above optional embodiments, it should be noted that the forced axial flow fan 1 is equipped with two power supplies and a wind power interlock device to ensure that the backup fan is started within 10 minutes after the ventilator in use fails, so as to ensure that tunnel ventilation and normal operation are not affected.

[0097] Optionally, the cable layout for the two power supplies adopts a double-sided suspended cabling scheme at the tunnel arch, with the main cable and the backup power cable laid independently on the left and right sides of the tunnel's longitudinal centerline, maintaining a spacing of more than 1.2 meters.

[0098] The cable support adopts an adjustable spring clamp structure, with vibration dampers installed every 3 meters, and is filled with silicone shock-absorbing pads.

[0099] The advantages of the above-mentioned optional embodiments are as follows: the dual power supply configuration avoids the risk of ventilation interruption caused by line faults, equipment maintenance, or external power outages in the traditional single power supply mode. When one power supply fails, the other power supply can be automatically switched immediately to ensure the continuous and stable operation of the forced axial flow fan 1, avoiding major safety hazards such as the accumulation of harmful gases at the working face and oxygen deficiency and suffocation of construction personnel caused by ventilation cessation. Especially in strata where gas is prone to accumulate, this design can significantly reduce the risk of explosion and improve the inherent safety level of tunnel construction.

[0100] Two power supplies are connected in parallel to the forced-flow axial fan 1, supporting two modes of operation: one for standby and the other for simultaneous operation. During normal construction, a single power supply or dual power supply can be flexibly selected according to ventilation needs. The air volume can be dynamically controlled by adjusting the number of operating fans, ensuring air quality while reducing energy consumption. In emergency situations such as mudslides or water inrushes, the dual power supply can ensure that all fans operate at full load, quickly expelling toxic and harmful gases or fumes, buying valuable time for emergency rescue.

[0101] Optional, such as Figure 1 and Figures 5 to 7 As shown, the installation method of flexible duct 2 includes, Mark the position of the expansion screws and install them; Arrange the guy wires, place them on the expansion bolts, and use a tensioner to straighten and fix them; The flexible air duct 2 is arranged such that a hanging ring is placed on the pull line at every first preset distance, and the flexible air duct 2 is inserted into the hanging ring.

[0102] In the above optional embodiments, it should be noted that the first preset distance is between 5 meters and 15 meters, preferably 10 meters.

[0103] The installation of flexible duct 2 should be flat, straight, and free from twisting and wrinkles. During operation, the surveyor should first determine the centerline position on the arch, then drill holes and install expansion bolts. In the main tunnel, bolt positions should be marked every 5 meters along the lining template joints in the lining sections. In unlined sections, the surveyor should first mark the horizontal position on the sidewalls, then drill holes and install expansion bolts. Lay No. 8 galvanized iron wire and tension it with a tensioner. Flexible duct 2 should be suspended from the guy wire. To prevent wire breakage due to shock wave vibration or corrosion from humid air inside the tunnel, an additional nylon rope hanging loop should be added every 10 meters. If flexible duct 2 is damaged, it should be repaired or replaced promptly. When using flexible duct 2, reinforced flexible ducts should be used near the fan. The section length of flexible duct 2 should be maximized to reduce the number of joints. Joints should be tight, and the average air leakage rate per 100 meters should not exceed 1%. The bending radius of the bend in the plane axis of the bend shall not be less than three times the diameter of the flexible duct.

[0104] The advantages of the above optional embodiments are: by accurately calibrating and installing the expansion bolts, a reliable mechanical anchoring point is provided for the suspension system of the flexible air duct 2.

[0105] By fixing expansion bolts at preset intervals on the tunnel arch or sidewall, the weight of the flexible air duct 2 and the airflow pressure can be evenly distributed, avoiding the problem of pipe sagging or disconnection caused by excessive spacing between fixing points, ensuring the continuity of the air supply path and structural stability, and is especially suitable for complex environments with humidity and vibration in tunnels.

[0106] The combined application of guy wires and tensioners creates an elastic support system. The straightened and fixed guy wires form a continuous suspension baseline, providing uniform support for the flexible duct 2. The tensioner can also dynamically adjust the wire tension to adapt to cross-sectional changes in different tunnel sections. This avoids the rigid compression of the flexible duct 2 by traditional rigid supports, reduces duct wrinkles and airflow resistance, and keeps the flexible duct 2 in a straight and relaxed state, improving air delivery efficiency.

[0107] The preferred spacing between the hanging rings and the flexible duct 2 is 10 meters, ensuring pipeline stability while providing the system with flexible adjustment capabilities. Hanging rings at fixed intervals avoid increased installation costs due to overly dense hanging and prevent sagging and deformation of the flexible duct 2 caused by excessive spacing. The flexible duct 2 is suspended from the guy wire by the hanging rings, allowing for convenient extension or disassembly and retrieval as excavation progresses, significantly improving pipeline maintenance efficiency during construction. This design addresses issues such as high force, providing reliable pipeline support for the efficient operation of the tunnel ventilation system.

[0108] Optionally, after the flexible duct 2 is installed, a reflective sticker is placed on the flexible duct 2 at second preset intervals.

[0109] In the above optional embodiments, it should be noted that the second preset distance is between 8 meters and 12 meters, preferably 10 meters.

[0110] The arrangement of reflective stickers may also include a biomimetic scale-like reflective sticker layout in the bends and diameter change areas of the flexible air duct 2. The reflective units are arranged in a streamlined manner, and each reflective sticker has a 0.5mm guide angle at its edge. The Coanda effect is used to form local airflow adhesion, and the airflow separation status is visualized by the vibration frequency of the reflective strip.

[0111] The advantages of the above-mentioned optional embodiments are as follows: Arranging reflective stickers at intervals on the flexible air duct 2 can significantly improve the safety warning effect of the construction environment inside the tunnel. The reflective stickers form continuous warning signs by reflecting light, making it easy for construction personnel to quickly identify the location of the flexible air duct 2 and avoid ventilation interruptions caused by mechanical collisions with the duct. At night or under low light conditions, the conspicuous warnings of the reflective stickers can effectively reduce the risk of personnel tripping and equipment scratching, improving the construction safety factor. At the same time, it provides clear spatial positioning marks for emergency rescue, ensuring the safety and orderliness of tunnel construction.

[0112] Optional, such as Figure 1 and Figure 8 As shown, methods for tunnel ventilation using cross passages include: At least one explosion-proof exhaust axial flow fan 5 is installed at the entrance and exit of the main tunnel. The cross passage is used for tunnel ventilation. Fresh air enters from the cross passage and is extracted from the entrance and exit of the main tunnel to form a circulating airflow.

[0113] The arrangement of the exhaust-type axial flow fan 5 is the same as that of the forced-flow axial flow fan 1, and will not be discussed further here.

[0114] The advantages of the above-mentioned optional embodiments are as follows: Explosion-proof exhaust-type axial flow fans 5 are arranged at the entrance and exit of the tunnel arch to form a tunnel-like ventilation system, which can utilize the through space to construct an efficient airflow circulation system. Through the coordinated extraction and exhaust by the fans at both ends, harmful gases and dust in the tunnel are quickly discharged, solving the problem of high ventilation resistance over long distances, achieving uniform ventilation throughout the tunnel, improving ventilation efficiency while reducing the risk of gas accumulation, and providing a safe and stable air environment for subsequent operations.

[0115] Optional, such as Figure 1 As shown, the methods for dust control in tunnels include: For ventilation and dust prevention, the flexible air duct 2 is suspended on one side of the tunnel and made parallel to the tunnel. Wet drilling is carried out using a drilling and rock-drilling frame; the tunneling face is washed before blasting and muck removal. For dust suppression, wet spraying is used throughout the tunnel.

[0116] In the above optional embodiments, it should be noted that the specific dust prevention measures include a combination of technical measures such as ventilation dust prevention, spray dust suppression, wet operation, dust source reduction and personal protection.

[0117] The function of ventilation and dust control is to dilute and remove dust from the air inside the tunnel. In order to avoid the airflow blown out by the flexible air duct 2 from forming eddies at the working face or blowing directly onto the slag pile and increasing the dust content in the air, the flexible air duct 2 is suspended on one side of the tunnel and its axis is parallel to the tunnel.

[0118] The specific method for wet drilling using a drilling rig in wet drilling operations is as follows: The entire working face is drilled using a remote, isolated drilling rig, ensuring sufficient water supply and a water pressure of no less than 0.3 MPa. This ensures that the bottom of the hole is filled with water while isolating it from air, thus preventing dust generation. Air contamination in the water should be minimized. A small amount of wetting agent is added to the water to reduce its surface tension and improve its adsorption capacity for fine dust particles; the typical dosage of wetting agent is 0.05–0.5%. When drilling is required in other areas, a combined ventilation and water system must be used to prevent drilling dry holes.

[0119] The specific method for washing the tunnel face before blasting and muck removal is as follows: After blasting and before muck removal, use a water gun to gradually wash the tunnel roof and sides from the inside out. The water gun should be 15-20m away from the working face, and the water pressure should generally be 3-5 kgf / cm². 2 Before and during the loading of slag, continuously sprinkle water onto the slag pile until it is thoroughly wet; for dry slag, the water spraying rate is 4–8 L / m³. 3If the stone chips are very moist, then sprinkle less water or no water at all.

[0120] Specific methods for dust control in shotcrete include using wet spraying technology for all shotcrete operations inside the tunnel to fundamentally reduce the amount of dust generated during shotcrete operations; and installing local ventilation fans at the shotcrete work surface to improve the working environment.

[0121] Methods to reduce dust sources include moving processing operations that can be carried out outside the tunnel, such as electric welding, oxy-fuel welding, and concrete mixing, to the outside to reduce dust sources.

[0122] Personal protective measures include providing construction workers inside the tunnel with protective equipment such as dust masks, compressed air respirators, and dust helmets to maximize dust protection.

[0123] The advantages of the above-mentioned optional embodiments are as follows: the ventilation and dust prevention measures involve suspending the flexible duct 2 parallel to one side of the tunnel, forming a linkage effect of ventilation, wind, rain, and dust reduction through directional airflow organization. The stable airflow can accelerate the diffusion of dust to the predetermined area, and together with the exhaust of the forced axial flow fan 1, achieve efficient dust purification, avoiding the airflow turbulence and dust retention problems caused by the random layout of traditional flexible duct 2, thus optimizing the basic conditions for dust prevention from the perspective of environmental layout.

[0124] Wet operation is used throughout the entire drilling and slag removal process: The wet drilling process of drilling and rock drilling frame reduces dust generation during the drilling stage by more than 80% through real-time mixing of high-pressure water and rock powder, thus suppressing dust generation at the source; the washing operation of the tunneling face before blasting and slag removal can effectively remove floating dust from the rock wall and the surface of the deposits, reduce secondary dust caused by blasting vibration and mechanical operation, and reduce the risk of dust diffusion in subsequent processes.

[0125] The application of wet spraying technology throughout the tunnel completely changes the high dust defect of traditional dry spraying technology, significantly reducing the dust generation rate during the spraying process, while improving the density of concrete and the strength of the support, thus achieving a dual optimization of dust control effect and project quality.

[0126] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A tunnel ventilation construction method, characterized in that, include: For ventilation in the import work area and the cross tunnel work area, fresh air is injected into the excavation face using a single-machine, single-pipe forced-in method. Ventilation is carried out after the tunnel is completed. The method of using cross passages for tunnel ventilation is used to ventilate the tunnel. Dust control measures are implemented throughout the entire tunnel excavation process.

2. The tunnel ventilation construction method according to claim 1, characterized in that, The ventilation of the inlet work area and the cross tunnel work area, using a single-machine, single-pipe forced-in method to inject fresh air into the excavation face, includes the following methods: For ventilation of the imported work area, a forced axial flow fan (1) is arranged at the tunnel entrance (4) and a flexible air duct (2) is configured to inject fresh air into the excavation face using a single-unit single-duct forced injection method; Ventilation in the early stage and later stage of construction of the cross tunnel area is carried out by arranging a forced axial flow fan (1) and configuring a flexible air duct (2) at the entrance (3) of the cross tunnel. Fresh air is injected into the corresponding excavation face by a single machine and a single duct forced in. During the mid-term ventilation of the cross tunnel construction area, at least two of the aforementioned forced axial flow fans (1) are arranged at the cross tunnel entrance (3). Each of the aforementioned forced axial flow fans (1) is equipped with a flexible air duct (2). Fresh air is injected into the main tunnel's large and small mileage excavation faces by a single-unit, single-pipe forced injection method.

3. The tunnel ventilation construction method according to claim 2, characterized in that, The arrangement method of the forced axial flow fan (1) includes: Install the pressure-driven axial flow fan (1) and silencer according to the drawings; After installation quality inspection and trial operation, the painting process will begin.

4. The tunnel ventilation construction method according to claim 3, characterized in that, The installation method of the forced-flow axial fan (1) includes: Civil engineering construction, including the construction of civil engineering foundation structures; The forced-flow axial fan (1) is installed on the civil engineering foundation; Diffuser and duct installation: Install the diffuser at the outlet of the pressurized axial flow fan (1) and connect the duct to the diffuser.

5. The tunnel ventilation construction method according to claim 4, characterized in that, The method for installing the muffler includes: The upper and lower silencers are installed between the silencers and connected by connectors to form a silencer. The silencer is installed between the casing of the forced axial flow fan (1) and the silencer is installed on the top plate and bottom plate of the casing respectively; The housing is installed between the housing and the forced axial flow fan (1), and the forced axial flow fan (1) is installed inside the housing.

6. The tunnel ventilation construction method according to any one of claims 2-5, characterized in that, Before arranging the forced axial flow fan (1), two power supplies are installed in the tunnel, and both power supplies are electrically connected to the forced axial flow fan (1).

7. The tunnel ventilation construction method according to any one of claims 2-5, characterized in that, The installation method of the flexible air duct (2) includes: Mark the position of the expansion screws and install the expansion screws; Arrange the pull wire, place the pull wire on the expansion screw, and straighten and fix it with a tensioner; The flexible air duct (2) is arranged such that a hanging ring is arranged on the pull line at each first preset distance, and the flexible air duct (2) is inserted on the hanging ring.

8. The tunnel ventilation construction method according to claim 7, characterized in that, After the flexible air duct (2) is arranged, a reflective sticker is arranged on the flexible air duct (2) at a second preset distance.

9. The tunnel ventilation construction method according to claim 1, characterized in that, The method of using transverse tunnels for tunnel ventilation includes: At least one explosion-proof exhaust axial flow fan (5) is installed at the entrance and exit of the main tunnel. The cross passage is used for roadway ventilation. Fresh air is drawn in from the cross passage and drawn out from the entrance and exit of the main tunnel to form a circulating airflow.

10. The tunnel ventilation construction method according to claim 2, characterized in that, The method for dust control in tunnels includes: For ventilation and dust prevention, the flexible air duct (2) is suspended on one side of the tunnel and made parallel to the tunnel. Wet drilling is carried out using a drilling and rock-drilling frame; the tunneling face is washed before blasting and muck removal. For dust suppression, wet spraying is used throughout the tunnel.

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