Multi-working-face tunnel construction ventilation intelligent air volume balance distribution and control system

Abstract

The invention discloses an intelligent air quantity balance distribution and control system for multi-working-face tunnel construction ventilation, which is characterized in that a closed-loop ventilation control system consisting of a main ventilation device, an intelligent air quantity distribution valve group, a branch ventilation pipeline, a working face environment monitoring unit and a central control unit is built; the basic required air volume of each working face is calculated based on a multi-factor superposition method, then the required air volume is dynamically corrected in combination with real-time environment parameters and operation states, the air volume distribution proportion is determined through a fuzzy control algorithm, an intelligent air volume distribution valve set is driven to adjust the air volume of branch pipelines, and closed-loop optimization is achieved in cooperation with a PID adjustment algorithm. The intelligent air distribution valve bank adopts a modular design, and can be flexibly adapted to different numbers of working surfaces; through multi-algorithm linkage and all-parameter monitoring, accurate air supply according to needs is achieved, the ventilation efficiency, construction safety and economical efficiency can be remarkably improved, and the method is suitable for multi-working-face tunnel construction under various complex geological conditions.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction safety assurance and intelligent ventilation technology, specifically to an intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation. Background Technology

[0002] During tunnel construction, to ensure the safety of workers and improve the working environment, fresh air needs to be supplied into the tunnel through a ventilation system to dilute and expel harmful gases, dust, and exhaust fumes from blasting and construction machinery. With the expansion of tunnel engineering scale and the improvement of construction efficiency, the multi-face synchronous construction mode (such as the opening of multiple main tunnel excavation faces with the assistance of inclined shafts and cross tunnels) has become the mainstream, and the corresponding "one-to-n" ventilation mode (one main ventilation system supplies air to n working faces simultaneously) is widely used.

[0003] The existing "one-to-many" ventilation mode has many drawbacks: First, its air volume distribution method mostly uses fixed-diameter diverter joints or manually adjustable valves to distribute air volume, which cannot dynamically adjust the air volume according to the real-time operating conditions of each working face. For example, when a working face is carrying out high-intensity pollution operations such as blasting or muck removal and requires a large air volume for enhanced ventilation, other working faces that are in regular operation or shutdown will still receive a fixed proportion of air volume. This results in insufficient air volume and untimely pollution removal for the enhanced ventilation working face, while the regular operation working face has excessive air volume, causing energy waste. Second, there is a lack of accurate air volume monitoring and feedback mechanisms. Existing technologies mostly only install wind speed sensors on the main pipeline or a few branch pipelines, making it difficult to obtain the actual air volume and environmental parameters of each working face in real time, and failing to achieve closed-loop control of air volume. Third, the existing ventilation mode has poor adaptability. For different combinations of working faces with different numbers and operation types, it is necessary to manually readjust the ventilation pipeline or valve parameters, which is cumbersome and has a slow response, making it difficult to meet the needs of complex and ever-changing tunnel construction environments.

[0004] While existing technologies offer some improvements for ventilation across multiple working faces, such as using air chambers for initial airflow distribution or employing mechanically adjustable airflow distribution controllers, the former fails to address the issue of precise dynamic airflow matching, while the latter relies on manual operation, resulting in low adjustment accuracy and slow response, making it unsuitable for the trend towards intelligent construction. Therefore, developing an intelligent airflow balance distribution and control system capable of delivering precise, on-demand airflow to multiple working faces ("one-to-many") and avoiding localized over- or under-airflow has become a pressing technical challenge in tunnel construction ventilation. Summary of the Invention

[0005] This invention provides an intelligent air volume balance distribution and control system for ventilation in multi-face tunnel construction. By designing an intelligent air volume distribution valve group and constructing a closed-loop control system, it achieves precise dynamic distribution of air volume for "one-to-n" working faces, solves the problem of excessive or insufficient local air volume in ventilation of "one-to-n" multi-face tunnels, improves ventilation efficiency and reduces energy consumption.

[0006] One embodiment of the present invention provides an intelligent air volume balance distribution and control system for ventilation in multi-face tunnel construction. The system includes main ventilation equipment, intelligent air volume distribution valve group, branch ventilation pipelines, working face environmental monitoring unit and central control unit. The main ventilation equipment is used to provide airflow. The main ventilation equipment is connected to the main ventilation duct. The main ventilation duct is connected to n branch ventilation ducts. Each branch ventilation duct corresponds to a tunnel construction working face. The intelligent air volume distribution valve group is set at the connection between the main ventilation duct and n branch ventilation ducts. By distributing the airflow to each branch ventilation duct, a "one-to-n" ventilation layout is achieved. The working face environment monitoring unit is used to collect real-time environmental parameters and operation status parameters of the working face using multiple sensors installed on each working face; The central control unit is used to calculate the basic air volume requirement for each working face based on the operation type and parameters of each working face; receive data collected by the working face environmental monitoring unit and the intelligent air volume distribution valve group in real time, and dynamically correct the basic air volume requirement; calculate the total air volume requirement and the air volume distribution ratio of each branch pipe based on the corrected air volume requirement of each working face, so as to realize the intelligent air volume distribution and control of the total air volume requirement and the air volume of each branch pipe; and realize the closed-loop feedback and optimization of air volume control by comparing the actual air volume with the target air volume.

[0007] Furthermore, the intelligent air volume distribution valve group includes an electrically adjustable blade, a drive module, a flow sensor, and a remote data receiving and transmitting module. The drive module is used to drive the electrically adjustable blade to rotate. The electrically adjustable blade is used to adjust the ventilation cross-sectional area of ​​the branch ventilation duct by changing the duct coverage area. The flow sensor is used to collect the actual air volume data of the branch duct in real time. The remote data receiving and transmitting module is used to realize data interaction with the central control unit.

[0008] Furthermore, the working face environmental monitoring unit includes a hazardous gas sensor, a dust sensor, a personnel counter, and a wind speed sensor installed at the tunnel construction working face.

[0009] Furthermore, the central control unit is used to calculate the basic air volume requirement for each work surface based on the operation type and parameters of each work surface, including: Based on the operation type and parameters of each work surface, the basic air volume requirement for each work surface is calculated. The basic air volume requirement is calculated using a multi-factor superposition method, specifically including: a. Calculate the air volume required based on the maximum number of people working simultaneously inside the tunnel: According to the "Railway Tunnel Design Code", the air supply per person per minute shall not be less than 3m³. 3 The required air volume Q1 is calculated according to the following formula:

[0010] In the formula, k is the air volume reserve coefficient; N is the maximum number of people in the cave at the same time. b. Calculated based on the volume of airflow for diluting and discharging internal combustion engine exhaust gas: The required air volume Q2, based on the air volume for diluting and discharging internal combustion engine exhaust gas, is calculated using the following formula:

[0011] In the formula, q is the air supply required by the internal combustion engine per minute per kilowatt; N i The rated power of a single internal combustion engine; T i The utilization factor of the diesel engine equipment during operation; c. Calculate based on the air volume required for dilution and exhaust of blasting fumes: The required air volume Q3 for supply ventilation to dilute and exhaust blasting fumes is calculated based on the Volonin formula:

[0012] In the formula, b is the carbon monoxide equivalent produced per kilogram of explosive; G is the amount of explosive; A is the cross-sectional area of ​​the tunnel; L0 is the ventilation length; t is the ventilation time; C a The permissible concentration of CO produced by blasting; P q The ratio of air volume at the beginning and end of the ventilation duct within the ventilation section; The ventilation limit length is the length within the tunnel where fresh air is fully utilized and reaches the maximum permissible concentration. At this point, the air inside the tunnel is considered waste gas and cannot be used in subsequent tunnel sections. It needs to be exhausted outside the tunnel, and fresh air needs to be reintroduced to meet the needs of personnel and construction. If the ventilation section length exceeds the limit length L... 极限 In the above formula, L0 needs to be replaced by L 极限 Replacement, if less than L 极限 Then use L0 to calculate, L 极限 Calculate according to the following formula:

[0013] In the formula, The flux diffusion coefficient is denoted as ρ; d. Calculated based on the minimum permissible wind speed inside the tunnel: The working face air volume Q4 is calculated according to the following formula:

[0014] In the formula V min The minimum wind speed during tunnel excavation; S is the maximum area of ​​the tunnel excavation. e. Calculate Q1, Q2, Q3, and Q4 for each working face under each working condition and compare them to obtain the maximum required air volume value Q. max The maximum required air volume is the same as the basic required air volume Q. 需 =Q max .

[0015] Furthermore, the central control unit is used to receive real-time data from the working face environmental monitoring unit and the intelligent air volume distribution valve group, and to dynamically correct the basic air volume requirement, specifically including: When the concentration of harmful gases or dust at the working face is detected to exceed the preset threshold, the required air volume is increased proportionally to the excess value; when the number of personnel or machinery operating at the working face changes, the required air volume is adjusted synchronously; when the deviation between the actual air volume of the branch pipe and the corrected required air volume is detected to exceed the preset value, an air volume adjustment command is triggered.

[0016] Furthermore, the central control unit is used to calculate the total required air volume and the air volume distribution ratio of each branch duct based on the corrected air volume requirement of each working face, thereby realizing intelligent air volume distribution and control of the total required air volume and the air volume of each branch duct. Specifically, this includes: Based on the corrected air volume requirements of each work surface, the central control unit uses a fuzzy control algorithm to calculate the total air volume requirement and the air volume distribution ratio of each branch duct, and sends adjustment commands to the drive module of the intelligent air volume distribution valve group. The drive module drives the electric regulating blades to rotate, changing the ventilation cross-sectional area of ​​each branch duct to achieve precise air volume distribution. At the same time, the frequency converter of the main ventilation equipment adjusts the speed of the main fan in real time according to the total air volume requirement to ensure that the air supply of the main duct matches the total air volume requirement of each work surface, and avoids overload or inefficient operation of the main fan.

[0017] Furthermore, the central control unit is used to achieve closed-loop feedback and optimization of airflow control by comparing the actual airflow with the target airflow, specifically including: The flow sensor of the intelligent air volume distribution valve group and the wind speed sensor of the working face continuously collect air volume data and feed it back to the central control unit. The central control unit compares the actual air volume with the target air volume and fine-tunes the opening of the electric regulating blades and the speed of the main fan through the PID adjustment algorithm until the deviation between the actual air volume and the target air volume of each working face is less than the preset value, thereby realizing closed-loop balance control of air volume.

[0018] Furthermore, the central control unit has a built-in fault diagnosis module. When a fault is detected in the flow sensor, environmental sensor, or drive module, it immediately issues an alarm signal and automatically switches to emergency ventilation mode, supplying air to each work surface at the preset maximum safe air volume to ensure construction safety.

[0019] Furthermore, the central control unit communicates with the tunnel construction management platform to upload real-time ventilation system operation data and environmental data of each working face, supporting remote monitoring and manual intervention adjustment.

[0020] Furthermore, the intelligent air volume distribution valve group adopts a modular design, which can flexibly increase or decrease the number of branch pipe interfaces according to the number of working surfaces n, and a sealing rubber ring is set at the interface to reduce the air leakage rate.

[0021] This invention provides an intelligent air volume balance distribution and control system for ventilation in multi-face tunnel construction, which has the following beneficial effects: 1. This invention addresses the ventilation scenario of "one-to-n" multi-working-faces by designing a modular intelligent air volume distribution valve group, which enables independent and precise adjustment of the air volume in branch ducts, breaking through the limitations of traditional fixed distribution or manual adjustment; combined with fuzzy control algorithm and PID adjustment algorithm, a multi-parameter linkage closed-loop control system is constructed to achieve dynamic matching of air volume, solving the technical pain point of local air volume excess or deficiency.

[0022] 2. The basic air volume calculation of this invention covers multiple influencing factors such as personnel, wind speed, blasting, and machinery, and is suitable for tunnel construction under different geological conditions and operation types; the system has fault diagnosis and emergency ventilation functions, which improves the reliability of the ventilation system; it can be linked with the construction management platform to meet the management needs of intelligent construction.

[0023] 3. The sensors, electrically adjustable valves, and central controllers used in this invention are all mature industrial-grade products. Their modular design facilitates on-site installation and debugging. The control algorithm is simple and efficient, and can be implemented using existing industrial controllers without complex hardware upgrades, making it easy to promote and apply in engineering projects. Compared with existing technologies, this invention can reduce ventilation energy consumption by more than 20%, while shortening the removal time of harmful gases and dust from the working face by 30%, significantly improving construction efficiency and operational safety. Attached Figure Description

[0024] Figure 1 A schematic diagram of the overall layout of an intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation in a tunnel, provided as an embodiment of the present invention; Figure 2 This is a cross-sectional view of the internal structure of an intelligent air volume distribution valve group in a multi-face tunnel construction ventilation intelligent air volume balance distribution and control system provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of a working face environment monitoring unit in a multi-working-face tunnel construction ventilation intelligent air volume balance distribution and control system provided in one embodiment of the present invention; Figure 4 A schematic diagram of dynamic air volume correction in an intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation, provided as an embodiment of the present invention; Figure 5 This is a schematic diagram of the closed-loop control mechanism in an intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation, provided as an embodiment of the present invention. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0026] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0027] The first embodiment of the present invention provides an intelligent air volume balance distribution and control system for ventilation in multi-face tunnel construction, the specific contents of which are as follows: 1. System Setup: Construct a closed-loop ventilation control system consisting of "main ventilation equipment - intelligent airflow distribution valve group - branch ventilation ducts - working face environmental monitoring unit - central control unit". For example... Figure 1 As shown.

[0028] The main ventilation equipment is used to provide airflow. The main ventilation equipment is connected to the main ventilation duct, which is connected to n branch ventilation ducts. Each branch ventilation duct corresponds to a tunnel construction working face.

[0029] The intelligent air volume distribution valve group is set at the connection between the main ventilation duct and n branch ventilation ducts. Each branch ventilation duct corresponds to a construction work surface, realizing a "one-to-n" ventilation layout.

[0030] like Figure 1 As shown, the main ventilation duct connects the external ventilation fan into the tunnel, its function being to guide airflow into the tunnel; the branch ventilation ducts are the ducts distributed through intelligent distribution valves, the specific number depending on the site, their function being to guide the distributed airflow to each construction excavation face; the working face is the excavation face at the very beginning of the tunnel excavation, and each excavated tunnel has a working face in front of it, corresponding to... Figure 1 The number of tunnel faces in the middle section also depends on the site conditions.

[0031] like Figure 2 As shown, the intelligent air volume distribution valve group includes a valve body, an electric adjusting blade, a drive module, and a flow sensor. The electric adjusting blade is used to adjust the ventilation cross-sectional area of ​​the branch ventilation ducts, and the flow sensor collects the actual air volume data of each branch duct in real time.

[0032] like Figure 3 As shown, the working face environmental monitoring unit includes hazardous gas sensors (detecting CO, NOx, etc.), dust sensors, personnel counters, and wind speed sensors installed on each working face to collect real-time environmental parameters and operational status parameters of the working face.

[0033] 2. Basic Air Volume Calculation: The central control unit calculates the basic air volume requirement for each work surface based on the operation type and parameters of each work surface. The basic air volume requirement is calculated using a multi-factor superposition method, specifically including: ① Calculate the air volume based on the maximum number of people working simultaneously inside the tunnel: According to the "Code for Design of Railway Tunnels" (TB10003-2016), the air supply per person per minute shall not be less than 3 m³ / min. 3 Calculate the required air volume using the following formula. Q 1:

[0034] In the formula k The air volume reserve factor is set at 1.2. N This represents the highest number of people inside the cave at any given time.

[0035] ② Calculated based on the volume of air used for diluting and discharging internal combustion engine exhaust gas: The ventilation volume required for internal combustion engines used inside tunnels varies greatly due to differences in engine model, structure, fuel, load, and technical condition. It is generally calculated based on the unit air volume required by the rated power of the internal combustion engine. The required air volume is also calculated based on the air volume needed to dilute and exhaust the engine's exhaust gases. Q 2. Calculate using the following formula:

[0036] In the formula q According to the "Railway Tunnel Design Code" (TB10003-2016), the required air supply per minute per kilowatt for an internal combustion engine should not be less than 3 m³ / min when using internal combustion machinery. 3 / (min·kW); N i Rated power (kW) for a single internal combustion engine; T i This is the utilization factor of the diesel engine equipment during operation.

[0037] ③ Calculate based on the air volume required for dilution and exhaust of blasting fumes: The required air volume for forced-air ventilation to dilute and exhaust blasting smoke Q 3 can be calculated using the Voronin formula:

[0038] In the formula b The carbon monoxide equivalent produced per kilogram of explosive is taken as 40 L / kg; G This refers to the amount of explosives. A The cross-sectional area of ​​the tunnel; L 0 represents the ventilation length (m); t Ventilation time (min); C a The permissible concentration (%) of CO produced by blasting is set to 0.02. P q The ratio of the air volume at the beginning and end of the ventilation duct within the ventilation section is taken as 1.

[0039] The ventilation limit length is the length within a tunnel where fresh airflow is fully utilized and reaches the maximum permissible concentration. At this point, the air inside the tunnel is considered waste gas and cannot be used in subsequent tunnel sections. It needs to be exhausted outside the tunnel, and fresh air needs to be reintroduced to meet the needs of personnel and construction. If the ventilation section length exceeds the limit length... L 极限 In the formula L 0 should be used L 极限 Substitute; if less than L 极限 Then use L0 for calculation. L 极限 Calculate according to the following formula:

[0040] In the formula is the flux diffusion coefficient, with a value of 0.8.

[0041] ④ Calculated based on the minimum permissible wind speed inside the tunnel: According to the "Code for Design of Railway Tunnels" (TB10003-2016), for tunnels constructed using the drill-and-blast method, the ventilation velocity inside the tunnel should not be less than 0.15 m / s when using full-face excavation and not less than 0.25 m / s when using sectional excavation. Therefore, the ventilation volume at the working face... Q 4 can be calculated using the following formula:

[0042] In the formula V min The minimum wind speed during tunnel excavation is taken as 0.15 m / s; S This refers to the maximum area to be excavated in the tunnel.

[0043] Finally, the calculations for each working condition and working face were performed. Q 1. Q 2. Q 3. Q 4. Compare the two values; the maximum required air volume is the same as the basic required air volume. Q 需 = Q max .

[0044] 3. Dynamic airflow correction: such as Figure 4 As shown, the central control unit receives real-time data from the working face environmental monitoring unit and the intelligent air volume distribution valve group, and dynamically corrects the basic air volume requirement. When the concentration of harmful gases or dust at the working face exceeds the preset threshold, the required air volume is increased proportionally to the excess multiple (e.g., 1.2-1.5 times, depending on the actual setting). When the number of personnel or machinery operating at the working face changes, the required air volume is adjusted synchronously. When the deviation between the actual air volume of the branch pipe and the corrected required air volume exceeds 5%, an air volume adjustment command is triggered.

[0045] 4. Intelligent air volume distribution and control: Based on the corrected air volume requirements of each working surface, the central control unit uses a fuzzy control algorithm to calculate the total air volume requirement and the air volume distribution ratio of each branch duct, and sends adjustment commands to the drive module of the intelligent air volume distribution valve group; the drive module drives the electric regulating blades to rotate, changing the ventilation cross-sectional area of ​​each branch duct, so as to achieve precise air volume distribution; at the same time, the frequency converter of the main ventilation equipment adjusts the fan speed in real time according to the total air volume requirement to ensure that the air supply of the main duct matches the total air volume requirement of each working surface, and avoids the main fan from being overloaded or operating inefficiently.

[0046] 5. Closed-loop feedback and optimization: such as Figure 5As shown, the flow sensor of the intelligent air volume distribution valve group and the wind speed sensor of the working face continuously collect air volume data and feed it back to the central control unit. The central control unit compares the actual air volume with the target air volume and fine-tunes the opening of the electric regulating blades and the speed of the main fan through the PID adjustment algorithm until the deviation between the actual air volume and the target air volume of each working face is less than 3%, thereby realizing closed-loop balance control of air volume.

[0047] In this embodiment, the intelligent airflow distribution valve group adopts a modular design, allowing for flexible adjustment of the number of branch pipe interfaces based on the number of working faces n (n≥2). Sealing rubber rings are installed at the interfaces to reduce air leakage. Furthermore, the central control unit has a built-in fault diagnosis module. When a fault is detected in the flow sensor, environmental sensor, or drive module, an alarm signal is immediately issued, and the system automatically switches to emergency ventilation mode, supplying air to each working face at the preset maximum safe airflow to ensure construction safety. The central control unit can also communicate with the tunnel construction management platform, uploading real-time ventilation system operation data and environmental data for each working face, supporting remote monitoring and manual intervention adjustments.

[0048] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A smart air volume balance distribution and control system for ventilation in multi-face tunnel construction, characterized in that, The system includes main ventilation equipment, intelligent air volume distribution valve group, branch ventilation ducts, working face environmental monitoring unit and central control unit; The main ventilation equipment is used to provide airflow. The main ventilation equipment is connected to the main ventilation duct. The main ventilation duct is connected to n branch ventilation ducts. Each branch ventilation duct corresponds to a tunnel construction working face. The intelligent air volume distribution valve group is installed at the connection between the main ventilation duct and n branch ventilation ducts. By distributing the airflow to each branch ventilation duct, a "one-to-n" ventilation layout is achieved. The working face environment monitoring unit is used to collect real-time environmental parameters and operation status parameters of the working face using multiple sensors installed on each working face; The central control unit is used to calculate the basic air volume requirement for each working face based on the operation type and parameters of each working face; receive data collected by the working face environmental monitoring unit and the intelligent air volume distribution valve group in real time, and dynamically correct the basic air volume requirement; calculate the total air volume requirement and the air volume distribution ratio of each branch pipe based on the corrected air volume requirement of each working face, so as to realize the intelligent air volume distribution and control of the total air volume requirement and the air volume of each branch pipe; and realize the closed-loop feedback and optimization of air volume control by comparing the actual air volume with the target air volume.

2. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The intelligent air volume distribution valve group includes an electric adjusting blade, a drive module, a flow sensor, and a remote data receiving and transmitting module. The drive module is used to drive the electric adjusting blade to rotate. The electric adjusting blade is used to adjust the ventilation cross-sectional area of ​​the branch ventilation duct by changing the duct coverage area. The flow sensor is used to collect the actual air volume data of the branch duct in real time. The remote data receiving and transmitting module is used to realize data interaction with the central control unit.

3. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The working face environmental monitoring unit includes a hazardous gas sensor, a dust sensor, a personnel counter, and a wind speed sensor installed at the tunnel construction working face.

4. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The central control unit is used to calculate the basic air volume requirement for each work surface based on the operation type and parameters of each work surface, including: Based on the operation type and parameters of each work surface, the basic air volume requirement for each work surface is calculated. The basic air volume requirement is calculated using a multi-factor superposition method, specifically including: a. Calculate the air volume required based on the maximum number of people working simultaneously inside the tunnel: According to the "Railway Tunnel Design Code", the air supply per person per minute shall not be less than 3m³. 3 The required air volume Q1 is calculated according to the following formula: In the formula, k is the air volume reserve coefficient; N is the maximum number of people in the cave at the same time. b. Calculated based on the volume of airflow for diluting and discharging internal combustion engine exhaust gas: The required air volume Q2, based on the air volume for diluting and discharging internal combustion engine exhaust gas, is calculated using the following formula: In the formula, q is the air supply required by the internal combustion engine per minute per kilowatt; N i The rated power of a single internal combustion engine; T i The utilization factor of the diesel engine equipment during operation; c. Calculate based on the air volume required for dilution and exhaust of blasting fumes: The required air volume Q3 for supply ventilation to dilute and exhaust blasting fumes is calculated based on the Volonin formula: In the formula, b is the carbon monoxide equivalent produced per kilogram of explosive; G is the amount of explosive; A is the cross-sectional area of ​​the tunnel; L0 is the ventilation length; t is the ventilation time; C a The permissible concentration of CO produced by blasting; P q The ratio of air volume at the beginning and end of the ventilation duct within the ventilation section; The ventilation limit length is the length within the tunnel where fresh air is fully utilized and reaches the maximum permissible concentration. At this point, the air inside the tunnel is considered waste gas and cannot be used in subsequent tunnel sections. It needs to be exhausted outside the tunnel, and fresh air needs to be reintroduced to meet the needs of personnel and construction. If the ventilation section length exceeds the limit length L... 极限 In the above formula, L0 needs to be replaced by L 极限 Replacement, if less than L 极限 Then use L0 to calculate, L 极限 Calculate according to the following formula: In the formula, The flux diffusion coefficient is denoted as ρ; d. Calculated based on the minimum permissible wind speed inside the tunnel: The working face air volume Q4 is calculated according to the following formula: In the formula V min The minimum wind speed during tunnel excavation; S is the maximum area of ​​the tunnel excavation. e. Calculate Q1, Q2, Q3, and Q4 for each working face under each working condition and compare them to obtain the maximum required air volume value Q. max The maximum required air volume is the same as the basic required air volume Q. 需 =Q max .

5. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The central control unit receives real-time data from the working face environmental monitoring unit and the intelligent air volume distribution valve group, and dynamically corrects the basic air volume requirement, specifically including: When the concentration of harmful gases or dust at the working face is detected to exceed the preset threshold, the required air volume is increased proportionally to the excess value; when the number of personnel or machinery operating at the working face changes, the required air volume is adjusted synchronously; when the deviation between the actual air volume of the branch pipe and the corrected required air volume is detected to exceed the preset value, an air volume adjustment command is triggered.

6. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The central control unit is used to calculate the total required air volume and the air volume distribution ratio of each branch duct based on the corrected air volume requirement of each working face, so as to realize intelligent air volume distribution and control of the total required air volume and the air volume of each branch duct. Specifically, it includes: Based on the corrected air volume requirements of each work surface, the central control unit uses a fuzzy control algorithm to calculate the total air volume requirement and the air volume distribution ratio of each branch duct, and sends adjustment commands to the drive module of the intelligent air volume distribution valve group. The drive module drives the electric regulating blades to rotate, changing the ventilation cross-sectional area of ​​each branch duct to achieve precise air volume distribution. At the same time, the frequency converter of the main ventilation equipment adjusts the speed of the main fan in real time according to the total air volume requirement to ensure that the air supply of the main duct matches the total air volume requirement of each work surface, and avoids overload or inefficient operation of the main fan.

7. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The central control unit is used to achieve closed-loop feedback and optimization of airflow control by comparing the actual airflow with the target airflow. Specifically, it includes: The flow sensor of the intelligent air volume distribution valve group and the wind speed sensor of the working face continuously collect air volume data and feed it back to the central control unit. The central control unit compares the actual air volume with the target air volume and fine-tunes the opening of the electric regulating blades and the speed of the main fan through the PID adjustment algorithm until the deviation between the actual air volume and the target air volume of each working face is less than the preset value, thereby realizing closed-loop balance control of air volume.

8. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The central control unit has a built-in fault diagnosis module. When a fault is detected in the flow sensor, environmental sensor or drive module, it will immediately issue an alarm signal and automatically switch to emergency ventilation mode, supplying air to each work surface at the preset maximum safe air volume to ensure construction safety.

9. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The central control unit communicates with the tunnel construction management platform, uploading real-time ventilation system operation data and environmental data for each working face, and supports remote monitoring and manual intervention adjustment.

10. The intelligent air volume balance distribution and control system for multi-face tunnel construction ventilation as described in claim 1, characterized in that, The intelligent air volume distribution valve group adopts a modular design, which can flexibly increase or decrease the number of branch pipe interfaces according to the number of working surfaces n, and the interface is equipped with a sealing rubber ring to reduce the air leakage rate.

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