Method for calculating air supply of diversion tunnel, ventilation dust reduction system and installation method

Abstract

This invention discloses a method for calculating the air supply volume of a water diversion tunnel, a ventilation and dust suppression system, and an installation method. Belonging to the technical field of ventilation equipment for water diversion tunnels, it includes calculating the fan air supply volume and fan pressure. The required ventilation volume inside the tunnel is calculated based on the air volume required by construction personnel, the minimum allowable wind speed, the air volume required for blasting smoke, and the air volume required by internal combustion machinery within the tunnel. The fan air supply volume is then calculated based on the required ventilation volume. Finally, the fan pressure is calculated based on the required ventilation volume and the fan air supply volume. This invention's method for calculating the air supply volume of a water diversion tunnel, its ventilation and dust suppression system, and its installation method allow for the selection of a suitable ventilation system based on the calculated maximum air supply volume of the water diversion tunnel, achieving ventilation and dust suppression during the excavation of the water diversion tunnel. The system is simple in structure, easy to assemble and disassemble, and cost-effective.

Description

Technical Field

[0001] This invention relates to the field of ventilation equipment technology for water diversion tunnels, specifically to a method for calculating the air supply volume of water diversion tunnels, a ventilation and dust suppression system, and an installation method. Background Technology

[0002] In the field of water conservancy and underground engineering construction, water diversion tunnels are key infrastructure for water resource allocation and energy development, and their construction technology directly affects the project's progress and safety. Among them, water diversion tunnels are often long-distance, small-section structures. Their long routes and limited cross-sectional space have become key and difficult scenarios in tunnel construction, especially in terms of ventilation, smoke extraction, and control of the working environment, which have long faced technical bottlenecks and urgently require targeted solutions.

[0003] From the perspective of cross-sectional characteristics, a "small cross-section" means that the effective working space after tunnel excavation is extremely limited. The cross-sectional size is usually constrained by engineering design and geological conditions, making it difficult to meet the spatial requirements for simultaneous multi-process operations. In actual construction, core processes such as excavation, support, and muck removal need to be carried out cyclically on the same working face. This not only leads to low construction efficiency but also restricts the application of large-scale mechanized equipment—such as high-efficiency tunneling machines and multiple auxiliary operating machines—due to space constraints, further exacerbating the tension of the construction pace. Simultaneously, frequent overlap of processes within the limited space and mutual interference between different work stages not only increase the difficulty of construction organization but also easily lead to safety hazards due to limited operating space, posing challenges to construction safety management. The "long distance" characteristic directly makes ventilation the primary challenge. As the tunnel excavation depth increases, the ventilation distance at a single opening can often reach hundreds or even thousands of meters, with airflow resistance increasing exponentially. Traditional ventilation methods struggle to effectively transport fresh air and quickly remove polluted air. On the one hand, the breathing of workers and the operation of construction machinery inside the tunnel continuously consume oxygen and produce pollutants such as carbon dioxide and mechanical exhaust. On the other hand, the excavation process (especially when using a cantilever tunneling machine) generates a large amount of dust. Excessive dust concentration not only severely reduces visibility at the working face, affecting construction accuracy and efficiency, but also causes irreversible damage to the respiratory system of workers. Long-term exposure to this environment can easily lead to occupational diseases such as pneumoconiosis. Furthermore, if blasting is used for excavation, the blasting fumes contain toxic and harmful gases such as carbon monoxide and nitrogen oxides. Their diffusion and dilution require sufficient ventilation. However, under long-distance ventilation conditions, the blasting fumes remain for an extended period, easily leading to localized accumulation of toxic gases, posing a direct threat to the lives of construction workers. Current ventilation solutions for tunnel construction are mostly suitable for large cross-sections and short to medium distances, and their ventilation equipment size and air supply design are difficult to adapt to the special needs of long-distance, small-cross-section tunnels. Using large-diameter ventilation ducts, while increasing ventilation volume, would further encroach on the already limited tunnel space, creating serious conflicts with the operation of construction machinery and personnel passage. Conversely, using small-diameter ventilation ducts would result in significant airflow reduction due to excessive wind resistance, failing to meet the needs of long-distance ventilation and pollutant dilution. Furthermore, existing solutions often focus solely on ventilation, lacking effective dust suppression coordination designs. This makes it difficult to address the persistently high dust concentrations within small cross-section spaces, leading to harsh construction environments and significant safety risks. This has become a core bottleneck restricting the efficient and safe construction of long-distance, small-section water diversion tunnels.

[0004] In conclusion, developing a construction ventilation and dust suppression system that can adapt to the characteristics of long-distance, small-section structures, balance efficient ventilation and precise dust suppression, and is easy to install and cost-effective is of great practical significance for improving the tunnel construction environment, ensuring the safety of workers, and improving the efficiency of engineering construction. It is also an urgent need for the current development of the industry. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings by providing a method for calculating the air supply volume of a water diversion tunnel, a ventilation and dust suppression system, and an installation method. Based on the calculated maximum air supply volume of the water diversion tunnel, the optimal ventilation system is selected to achieve ventilation and dust suppression during the excavation of the water diversion tunnel. The system is simple in structure, easy to assemble and disassemble, and cost-effective. To achieve the above objectives, this invention provides the following technical solution: The calculation method for the air supply volume of a water diversion tunnel includes the calculation of the air supply volume and air pressure of the fan. S11. Calculate the required ventilation volume inside the tunnel based on the air volume required by the construction personnel inside the tunnel, the air volume required for the minimum allowable wind speed, the air volume required for the smoke from blasting, and the air volume required for the internal combustion machinery and equipment inside the tunnel. S12. Calculate the air supply volume of the fan based on the required ventilation volume inside the tunnel; S13. Calculate the fan pressure based on the required ventilation volume and fan air supply volume.

[0006] Furthermore, in S11, the required air volume for construction workers inside the tunnel is calculated based on the number of workers inside the tunnel and the required air volume per person per minute; the required air volume for the minimum allowable wind speed is calculated based on the cross-sectional area of ​​the water diversion tunnel and the minimum allowable wind speed inside the tunnel; the required air volume for blasting smoke is calculated based on the amount of blasting explosives used, blasting harmful gases, and ventilation time; and the required air volume for internal combustion machinery inside the tunnel is calculated based on the required air volume for the use of internal combustion machinery and the total horsepower of the internal combustion machinery.

[0007] Furthermore, in S11, the required ventilation volume inside the tunnel is the maximum value among the air volume required by the construction personnel inside the tunnel, the air volume required for the minimum allowable wind speed, the air volume required for blasting smoke, and the air volume required for the internal combustion machinery and equipment inside the tunnel.

[0008] Furthermore, in S12, the fan supply volume is calculated based on the duct leakage coefficient, duct length, and required ventilation volume inside the tunnel.

[0009] Furthermore, in S13, the fan pressure is calculated based on the required ventilation volume inside the tunnel, the fan supply volume, the pipe length, the pipe diameter, and the pipe friction resistance coefficient.

[0010] The ventilation and dust suppression system for the water diversion tunnel includes a dust suppression system and a ventilation system selected according to the above method; the dust suppression system is located at the outlet of the ventilation system and is connected to the ventilation system through a plastic bucket, and is used to remove dust from the air extracted into the tunnel by the ventilation system.

[0011] Furthermore, the ventilation system includes a ventilator and a ventilation pipe; the ventilator is installed at the entrance of the water diversion tunnel via a bracket; one end of the ventilation pipe is connected to the inlet of the ventilator, and the other end enters the tunnel and leads to the excavation face of the water diversion tunnel.

[0012] Furthermore, the dust suppression system includes a pipe, a cloth air duct, and a water spraying device; one end of the pipe is connected to a plastic bucket, and the other end is equipped with a cloth air duct; a water spraying device is installed inside the pipe.

[0013] The installation method for the ventilation and dust suppression system in a water diversion tunnel, used for installing the aforementioned ventilation and dust suppression system in a water diversion tunnel, includes the following steps: S91. Determine the installation location of the ventilation fan, install the bracket, install the ventilation fan of the ventilation system on the bracket, and fix the ventilation fan to the outside of the water diversion tunnel entrance.

[0014] S92. Lay ventilation pipes, extending from the inlet of the ventilation fan at the tunnel entrance into the water diversion tunnel. During the laying process, keep the ventilation pipe body smooth and without bends or turns. When connecting adjacent ventilation pipe sections, ensure that the cross-sectional dimensions of the pipe body are consistent, and fill the joint gaps with sealing material.

[0015] S93. Install the dust suppression system, seal one side of the plastic bucket to the air outlet of the ventilator, seal the other side of the plastic bucket to the duct, and finally fix the cloth duct to the outlet end of the duct.

[0016] Furthermore, special adhesive is used to bond and repair the damaged parts of the ventilation duct.

[0017] The beneficial effects of this invention are: This invention discloses a method for calculating the air supply volume of a water diversion tunnel, a ventilation and dust suppression system, and an installation method. The method includes calculating the fan air supply volume and fan pressure. The required ventilation volume inside the tunnel is calculated based on the air volume required by construction personnel, the minimum allowable wind speed, the air volume required for blasting smoke, and the air volume required by internal combustion machinery within the tunnel. The fan air supply volume is then calculated based on the required ventilation volume. Finally, the fan pressure is calculated based on the required ventilation volume and the fan air supply volume. This invention's method for calculating the air supply volume of a water diversion tunnel, its ventilation and dust suppression system, and its installation method select the optimal ventilation system based on the calculated maximum air supply volume of the water diversion tunnel, achieving ventilation and dust suppression during the excavation of the water diversion tunnel. The system is simple in structure, easy to assemble and disassemble, and cost-effective. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the ventilation and dust suppression system of the present invention; In the attached diagram: 1-ventilation system, 11-fan, 12-ventilation duct, 2-dust suppression system, 21-pipe, 22-sprinkler device, 3-plastic bucket. Detailed Implementation

[0019] 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.

[0020] 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 “described” as used herein may also mean including 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 particular 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.

[0021] 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.

[0022] 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," "over," etc. The meaning of such spatial relative terms includes different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, then an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0023] Example 1: This invention discloses a method for calculating the air supply volume of a water diversion tunnel, including the calculation of the fan air supply volume and the fan air pressure. The fan air supply volume calculation includes calculating the required ventilation volume inside the tunnel based on the air volume required by construction personnel, the air volume required for the minimum allowable wind speed, the air volume required for blasting smoke, and the air volume required by internal combustion machinery and equipment inside the tunnel; calculating the fan air supply volume based on the required ventilation volume inside the tunnel; and then calculating the fan air pressure based on the required ventilation volume and the fan air supply volume.

[0024] I. Calculation of the required ventilation volume inside the cave.

[0025] 1) Formula for calculating the required air volume for construction workers inside the tunnel. Q1 = q × m × k × x1; Where q is the air volume required per person per minute, taken as 3m³ / min; m - Number of workers inside the tunnel; k-Air volume reserve factor: 1.1 to 1.15, take 1.15; x1 - Elevation correction factor for air volume required by construction personnel, taken as 1.4.

[0026] The required air volume q per person per minute, the air volume reserve coefficient k, and the correction coefficient x1 for the required air volume of construction personnel are all values ​​taken based on long-term construction experience.

[0027] 2) Formula for calculating the air volume required for the minimum permissible wind speed. Q2 = 60 × S × V; Where S represents the cross-sectional area of ​​the tunnel, in m². V - Minimum permissible wind speed inside the tunnel, taken as 0.15 m / s; The minimum permissible wind speed inside the tunnel is determined based on long-term construction experience.

[0028] 3) Formula for calculating the air volume required for smoke dispersion during blasting. Q3 = (5 × G × b) ÷ T ÷ x2; Wherein, G represents the amount of simultaneous blasting explosives used, in kg; b - Hazardous gases from explosions, take 40 L / kg; T - Ventilation time, in minutes; x2 - Correction factor for blasting smoke elevation, taken as 0.81; The values ​​for harmful gas 'b' from blasting and the elevation correction factor x2 for blasting smoke exhaust are both derived from long-term construction experience.

[0029] 4) Formula for calculating the required air volume for internal combustion mechanical equipment inside the tunnel. Q4 = Q0 × ΣP ’ ×x3; Among them, the air volume required for Q0-internal combustion mechanical equipment is taken as 4.08m³ / min·kW; ΣP ’ -Total horsepower of the internal combustion engines entering the tunnel, in kW; x3 - Elevation correction factor, taken as 3.0; The air volume Q0 and elevation correction factor x3 required for the use of internal combustion mechanical equipment are both values ​​taken based on long-term construction experience. Due to the small cross-section of the tunnel, the use of internal combustion equipment can be disregarded.

[0030] 5) The required ventilation volume inside the tunnel is the maximum value among the air volume required by construction personnel, the air volume required for the minimum allowable wind speed, the air volume required for blasting smoke, and the air volume required for internal combustion machinery and equipment inside the tunnel. The required ventilation volume inside the tunnel is: Q = max(Q1, Q2, Q3, Q4), unit m³ / min; II. Calculation of air supply volume of the fan.

[0031] The required ventilation volume inside the cave is calculated to determine the fan supply volume, which is: Q' = (1 + P × L / 100) × Q; Wherein, P is the duct leakage coefficient, taken as 1%; L - Length of ventilation duct, in meters; The air leakage coefficient of the pipeline is determined based on long-term construction experience.

[0032] III. Calculation of fan air pressure.

[0033] Calculate the fan pressure based on the required ventilation volume and fan supply volume calculated above. The fan pressure is: H f =1.15×H; Where H is the pipe resistance, calculated using the following formula: H f =6.5×a×L×Q×Q'÷d÷5; Where, a - the coefficient of frictional resistance of the pipeline, taken as 0.0006; d - Pipe diameter, in meters; The coefficient of frictional resistance of pipelines is determined based on long-term construction experience.

[0034] Example 2: This invention discloses a ventilation and dust suppression system for a water diversion tunnel, comprising a dust suppression system 2 and a ventilation system 1. The ventilation system 1 includes a fan 11 and a ventilation duct 12, while the dust suppression system 2 includes a pipe 21, a fabric air duct, and a water spraying device 22. Both the ventilation duct 12 and the pipe 21 are corrugated pipes. For the fan 11 and the ventilation duct 12, the air supply volume and air pressure of the fan 11 are calculated according to the air supply volume calculation method for water diversion tunnels in Embodiment 1. Based on the calculation results, the configuration of the fan 11 and the ventilation duct 12 is rationally determined to control costs. Since the cross-section of the water diversion tunnel is relatively small, using a large-diameter ventilation duct 12 would severely affect the operation of construction machinery inside the tunnel. Using a smaller-diameter ventilation duct 12 would result in greater air resistance, which would limit the air supply volume and distance. Considering all factors, ventilation ducts 12 with a diameter of 500mm to 700mm are commonly used in water diversion tunnels. The fan 11 is rationally selected based on the calculation results in Embodiment 1. After configuring the fan 11 and ventilation duct 12, connect and install the fan 11, ventilation duct 12 and dust suppression system 2. One end of the ventilation duct 12 is connected to the inlet end of the fan 11, and the other end extends into the water diversion tunnel to the excavation face of the water diversion tunnel. A plastic bucket 3 is provided at the outlet end of the fan 11, and the plastic bucket 3 is connected to one end of the pipe 21. The other end of the pipe 21 is provided with a cloth air belt, which seals the opening section of the pipe 21. A water sprinkler device 22 is provided inside the pipe 21. Through the cloth air belt and the water sprinkler device 22, the air drawn out from the water diversion tunnel is dusted.

[0035] Example 3: This invention discloses an installation method for a ventilation and dust suppression system in a water diversion tunnel, used for installing the ventilation and dust suppression system in Example 2, comprising the following steps: S91. Determine the installation location of the ventilator 11, install the bracket, and fix the ventilator 11 of the ventilation system 1 on the bracket so that the ventilator 11 is fixed outside the entrance of the water diversion tunnel.

[0036] S92. Laying Ventilation Pipe 12. Ventilation pipe 12 extends from the inlet of the ventilation fan 11 at the tunnel entrance into the water diversion tunnel. During laying, care must be taken to ensure that there are no bends or turns when entering the tunnel, guaranteeing the smoothness of the pipe and a consistent cross-section to facilitate smooth ventilation. Ventilation pipe 12 extends all the way to the excavation face, and the distance between ventilation pipe 12 and the excavation face should be no more than 8 meters to ensure optimal ventilation and dust removal effects.

[0037] S93. Install dust suppression system 2. A plastic bucket 3 is placed at the air outlet of the fan 11, connected to and sealed to the fan 11 outlet. A pipe 21 is connected to the other end of the plastic bucket 3, with water spraying inside for dust suppression. A fabric duct is installed at the outlet end of the pipe 21, blocking the outlet end to collect dust.

[0038] All technical features in this embodiment can be freely combined according to actual needs. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

[0039] The above embodiments are preferred implementations of the present invention. In addition, other implementations are also included. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A method for calculating the amount of air supplied to a water diversion tunnel, characterized by: This includes calculations of the fan's air supply volume and fan pressure. S11. Calculate the required ventilation volume inside the tunnel based on the air volume required by the construction personnel inside the tunnel, the air volume required for the minimum allowable wind speed, the air volume required for the smoke from blasting, and the air volume required for the internal combustion machinery and equipment inside the tunnel. S12. Calculate the air supply volume of the fan based on the required ventilation volume inside the tunnel; S13. Calculate the fan pressure based on the required ventilation volume and fan air supply volume.

2. The method of claim 1, wherein: In S11, the required air volume for construction workers inside the tunnel is calculated based on the number of workers inside the tunnel and the required air volume per person per minute; the required air volume for the minimum allowable wind speed is calculated based on the cross-sectional area of ​​the water diversion tunnel and the minimum allowable wind speed inside the tunnel; the required air volume for blasting smoke is calculated based on the amount of blasting explosives used, blasting harmful gases, and ventilation time; and the required air volume for internal combustion machinery inside the tunnel is calculated based on the air volume required for the use of internal combustion machinery and the total horsepower of the internal combustion machinery.

3. The method of claim 2, wherein: In S11, the required ventilation volume inside the tunnel is the maximum value among the air volume required by the construction personnel inside the tunnel, the air volume required for the minimum allowable wind speed, the air volume required for blasting smoke, and the air volume required for the internal combustion machinery and equipment inside the tunnel.

4. The method of claim 3, wherein: In S12, the air supply volume of the fan is calculated based on the air leakage coefficient of the ventilation duct, the length of the ventilation duct, and the required ventilation volume in the tunnel.

5. The method of claim 4, wherein: In S13, the fan pressure is calculated based on the required ventilation volume inside the tunnel, the fan supply volume, the length of the ventilation duct, the diameter of the ventilation duct, and the friction resistance coefficient of the ventilation duct.

6. A water diversion tunnel ventilation dust suppression system characterised by: It includes a dust suppression system (2) and a ventilation system (1) selected according to the method for calculating the air supply volume of the water diversion tunnel as described in any one of claims 1 to 5; the dust suppression system (2) is located at the outlet of the ventilation system (1) and is connected to the ventilation system (1) through a plastic bucket (3) to remove dust from the air in the tunnel extracted by the ventilation system (1).

7. The draft tunnel ventilation dust suppression system of claim 6, wherein: The ventilation system (1) includes a ventilator (11) and a ventilation pipe (12); the ventilator (11) is installed at the entrance of the water diversion tunnel by a bracket; one end of the ventilation pipe (12) is connected to the inlet of the ventilator (11), and the other end enters the tunnel and leads to the excavation face of the water diversion tunnel.

8. The draft tunnel ventilation dust suppression system of claim 6, wherein: The dust suppression system (2) includes a pipe (21), a cloth air belt and a water spraying device (22); one end of the pipe (21) is connected to a plastic bucket (3), and the other end is equipped with a cloth air belt; the water spraying device (22) is installed inside the pipe (21).

9. A method for installing a ventilation and dust suppression system for a water diversion tunnel, used for installing the ventilation and dust suppression system for a water diversion tunnel as described in any one of claims 6 to 8, characterized in that, Includes the following steps: S91. Determine the installation location of the ventilation fan, install the bracket, install the ventilation fan of the ventilation system on the bracket, and fix the ventilation fan to the outside of the water diversion tunnel entrance; S92. Lay ventilation pipes, extending from the inlet of the ventilation fan at the tunnel entrance into the water diversion tunnel. During the laying process, keep the ventilation pipe body smooth and without bends or turns. When connecting adjacent ventilation pipe sections, ensure that the cross-sectional dimensions of the pipe body are consistent and fill the joint gaps with sealing material. S93. Install the dust suppression system, seal one side of the plastic bucket to the air outlet of the ventilator, seal the other side of the plastic bucket to the duct, and finally fix the cloth duct to the outlet end of the duct.

10. The installation method of the ventilation and dust suppression system for water diversion tunnels according to claim 9, characterized in that: Specialized adhesive was used to bond and repair the damaged parts of the ventilation duct.

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