A tunnel network ventilation system and design method thereof

Abstract

The present invention belongs to the technical field of tunnel ventilation, and relates to a tunnel network ventilation system and a design method thereof, wherein the network ventilation system is used for air supply, exhaust or smoke exhaust, and comprises a plurality of main ventilation ducts respectively arranged in the interval tunnels of a multi-tube tunnel, the main ventilation ducts are provided with vents, both ends of the main ventilation ducts are provided with ventilation rooms and ventilation shafts, the two ends of the main ventilation ducts are respectively connected with the ventilation rooms at both ends, and the ventilation rooms are connected with the ventilation shafts; the main ventilation ducts in the adjacent two-tube tunnels are connected through parallel ducts arranged at intervals. The present invention connects a plurality of main ventilation ducts through parallel ducts arranged at intervals to form a ventilation network, greatly increases the number of ventilation paths, reduces the area of ​​the main ventilation ducts, increases the applicable length of the ventilation section under the condition of eliminating the intermediate air shaft, improves the system reliability and safety, reduces the project cost, reduces the difficulty of implementation, and effectively solves the problem that the existing long and large tunnels need to achieve ventilation by increasing the area of ​​the air ducts and the intermediate air shafts.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel ventilation, and in particular to a tunnel network ventilation system and a design method thereof. Background Art

[0002] For motor vehicle tunnels, subway tunnels and railway tunnels, ventilation systems are required in order to meet the requirements of ventilation, personnel comfort and temperature and humidity in the tunnels during normal operation, as well as the requirements of controlling smoke spread and providing an environment for safe evacuation of personnel under fire conditions. The required ventilation volume of the tunnel is usually proportional to the length of the tunnel. The longer the tunnel, the greater the required ventilation volume and the longer the ventilation time, and the higher the smoke exhaust requirements under disaster conditions. For rescue stations in urban road tunnels with a length of more than 3km or highway tunnels with a length of more than 5km, as well as subway tunnels and railway tunnels with a section length of more than 1.8km, it is necessary to set up intermediate air shafts or ventilation ducts to solve the ventilation and smoke exhaust problems of such long tunnels.

[0003] Since the construction cost of setting up ventilation ducts is low and the construction risk is small, it is usually preferred to add ventilation ducts in the tunnel. For urban road tunnels with a length of more than 8km and subway tunnels with a section length of more than 5km, the required ventilation volume increases significantly, resulting in a corresponding increase in the area of ​​the section ventilation duct. Due to the constraints of the tunnel structure, location, construction risks, etc., it is usually necessary to adopt a combined measure of increasing the area of ​​the duct + setting up an intermediate air shaft to solve the ventilation problem of such super-long tunnels. For tunnels crossing waters, it is usually impossible to set up an intermediate air shaft due to navigation restrictions, and the only solution is to increase the area of ​​the duct (expand the cross-section).

[0004] Increasing the air duct area and the intermediate air shaft will increase project investment, construction risks and later operating costs, resulting in poor project feasibility. Summary of the invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a tunnel network ventilation system and a design method thereof, which can reduce the air duct area, eliminate the intermediate air shaft, and improve the economy and feasibility of the project while ensuring the safety and reliability of the ventilation system.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is a tunnel network ventilation system, which is used for air supply, exhaust or smoke exhaust; the network ventilation system includes a plurality of main ventilation ducts respectively arranged in the interval tunnels of the multi-tube tunnel, the main ventilation ducts are provided with ventilation openings, and ventilation rooms and ventilation shafts are provided at both ends of the main ventilation ducts, the two ends of the main ventilation ducts are respectively connected with the ventilation rooms at both ends, and the ventilation rooms are connected with the ventilation shafts; the main ventilation ducts in two adjacent tube tunnels are connected through parallel air ducts arranged at intervals.

[0007] Furthermore, for subway tunnels, the interval between the parallel air ducts is no more than 1800m; for urban road tunnels, the interval between the parallel air ducts is no more than 3000m; for highway tunnels, the interval between the parallel air ducts is no more than 5000m.

[0008] Furthermore, the parallel air duct is connected to the position where the vent is set on the main ventilation duct.

[0009] Furthermore, the net area of ​​the main air duct is the same as the net area of ​​the parallel air duct.

[0010] Furthermore, two adjacent tube tunnels are connected through a transverse passage, and the transverse passage is divided into an upper space and a lower space by a flue plate, the upper space is the parallel air duct, and the lower space is a driving passage.

[0011] Furthermore, the fan in the ventilation room is a reversible fan.

[0012] The present invention also provides a design method for the above-mentioned tunnel network ventilation system, wherein the network ventilation system is used for exhausting smoke, and the ventilation opening is provided with a smoke exhaust valve, and the method comprises the following steps:

[0013] S1. Determine the number of parallel air ducts, spacing and specifications of smoke exhaust valves;

[0014] S2. Construct a ventilation network model based on the air leakage level of the main ventilation duct, the structural form of the smoke exhaust valve, and the sealing requirements of the connection between the smoke exhaust valve and the civil foundation;

[0015] S3, select two adjacent groups of smoke exhaust valves in the closed state and the main ventilation duct between them as the standard section, and calculate the equivalent resistance coefficient corresponding to different main ventilation duct pressures under the ventilation network model;

[0016] S4. Determine the smoke exhaust volume at the open smoke exhaust valve according to the fire scale and smoke exhaust plan;

[0017] S5. Propose the net area of ​​the air duct;

[0018] S6. For multiple smoke exhaust paths, the opened smoke exhaust valve is used as the starting point, and the area from the smoke exhaust valve to the smoke exhaust fan is divided into several standard sections. According to the resistance characteristics of the ventilation network, the air volume and air pressure of the standard section at the end of the ventilation network are calculated and determined;

[0019] S7. Design and select the type of smoke exhaust fan according to the calculation result of step S6. When the type of smoke exhaust fan meets the requirements, the proposed net area of ​​the air duct is the net area of ​​the main ventilation duct and the parallel air duct. When the type of smoke exhaust fan does not meet the requirements, return to step S5 to recalculate.

[0020] Furthermore, the calculation formula of the equivalent drag coefficient of the standard section in step S3 is as follows:

[0021]

[0022] Where: k0——equivalent resistance coefficient of standard section;

[0023] ρ——Smoke density, kg / m 3 ;

[0024] A0——Leakage area when the exhaust valve is closed, m 2 ;

[0025] Q n漏 ——Total air leakage in standard section, m 3 / S;

[0026] P——Main ventilation duct pressure in standard section, Pa.

[0027] Furthermore, the calculation formulas for the air volume and air pressure at the end point of the ventilation network in step S6 are as follows:

[0028]

[0029]

[0030] Where: n——standard section number, n=1, 2, 3...;

[0031] P n ——wind pressure in the standard section of the terminal, Pa;

[0032] P0——wind pressure at the vent, Pa;

[0033] P n1 ——along-the-way resistance of the standard section, Pa;

[0034] P n2 ——along-the-way resistance of the standard section, Pa;

[0035] Q n ——Air volume of the standard section at the end, m 3 / s;

[0036] Q0——air volume allocated to the calculated smoke exhaust path, m 3 / s;

[0037] Q n1 ——Air leakage of smoke exhaust valve in the standard section when closed, m 3 / s;

[0038] Q n2 ——Air leakage of main ventilation duct in standard section, m 3 / s.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention connects multiple main ventilation ducts to form a ventilation network through multiple parallel air ducts, which can greatly increase the number of ventilation paths, effectively reduce the area of ​​the main ventilation ducts, and significantly increase the applicable length of the ventilation section without the need for intermediate air shafts, thereby improving the reliability and safety of the ventilation system, reducing the cost of tunnel engineering, and reducing the difficulty of engineering implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A plan schematic diagram of a tunnel network ventilation system provided by an embodiment of the present invention;

[0043] Figure 2 A cross-sectional view of a tunnel network ventilation system provided by an embodiment of the present invention;

[0044] In the figure: 1-ventilation starting point; 2-ventilation end point; 3-ventilation room; 4-main ventilation duct; 5-parallel duct; 6-cross passage; 7-tunnel. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0047] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0048] Embodiment 1

[0049] The present embodiment provides a tunnel network ventilation system, which is used for air supply, exhaust or smoke exhaust; the network ventilation system includes a plurality of main ventilation ducts 4 respectively arranged in the interval tunnels of the multi-tube tunnel 7, and the main ventilation ducts 4 are provided with ventilation openings. Ventilation machine rooms 3 and ventilation shafts are provided at both ends of the main ventilation ducts 4, and the two ends of the main ventilation ducts 4 are respectively connected with the ventilation machine rooms 3 at both ends, and the ventilation machine rooms 3 are connected with the ventilation shafts; the main ventilation ducts 4 in two adjacent tube tunnels 7 are connected through parallel air ducts 5 arranged at intervals.

[0050] like Figure 1 As shown, the interval tunnel of each tube tunnel 7 has a ventilation starting point 1 and a ventilation end point 2, and the ventilation starting point 1 and the ventilation end point 2 are both provided with a ventilation machine room 3 and a ventilation shaft. Both ends of the main ventilation duct 4 in the interval tunnel are connected with the ventilation machine room 3 and the ventilation shaft. By arranging a plurality of parallel air ducts 5 at a certain interval between two adjacent tube tunnels 7, the main ventilation ducts 4 of the multi-tube tunnels 7 are connected to form a ventilation network, which greatly increases the ventilation path, makes full use of the area of ​​the main ventilation duct 4 of the multi-tube tunnel, and can effectively reduce the area of ​​the main ventilation duct 4 of each tube tunnel. Under the premise of not setting an intermediate air shaft, the length of the ventilation section can be significantly increased, and the number of ventilation paths is multiplied at the same time, which can also improve the safety and reliability of the ventilation system. It can be promoted, referenced and applied in the design of road tunnels, subway tunnels and railway tunnels.

[0051] In this embodiment, the ventilation rooms 3 at both ends of the main ventilation duct 4 can realize air supply, exhaust or smoke exhaust for a certain tube tunnel, and the fans in the ventilation rooms 3 correspond to the purpose of the system. Taking the two-tube tunnel as an example, a total of 4 ventilation rooms are set at both ends of the two main ventilation ducts. When a certain tube tunnel is on fire, the vents in the main ventilation duct of the fire tunnel are opened, and the fans in the 4 ventilation rooms are opened to discharge the fire smoke from the vents of the main ventilation duct of the fire tunnel, the parallel air duct, the main ventilation duct of the fire tunnel and the main ventilation duct of the non-fire tunnel to the 4 ventilation rooms, and then discharged from the ventilation shaft. When air supply or exhaust is required, only the opening direction of the fan is different, and the rest of the action methods are the same.

[0052] Among them, there are no ventilation facilities such as fans and smoke exhaust valves in the parallel air duct 5. When ventilation is needed, it is only necessary to turn on the fans in the ventilation rooms 3 at both ends of the main ventilation duct 4. Relying on the automatic distribution of airflow in the ventilation network, the ventilation needs of a certain section can be simultaneously supplied by multiple main ventilation ducts 4, which will not increase the difficulty and complexity of the control system, and the control and adjustment are simple and the reliability is high.

[0053] Furthermore, for subway tunnels, the interval between parallel air ducts 5 is not greater than 1800m. Specifically, the spacing should be determined in combination with the subway train tracking interval and the interval ventilation requirements; for urban road tunnels, the interval between parallel air ducts 5 is not greater than 3000m; for highway tunnels, the interval between parallel air ducts 5 is not greater than 5000m.

[0054] Optimally, the parallel air duct 5 is connected to the position where the vent is set on the main ventilation duct 4, which can improve the efficiency of air supply, exhaust or smoke exhaust.

[0055] Optimally, the net area of ​​the main air duct 4 is the same as the net area of ​​the parallel air duct 5 .

[0056] In this embodiment, the parallel air duct 5 can be combined with auxiliary channels such as the tunnel transverse channel 6. The two adjacent tube tunnels 7 are connected through the transverse channel 6. The cross section of the transverse channel is enlarged. The flue plate in the transverse channel 6 is used to separate the upper space and the lower space. The upper space is the parallel air duct 5, and the lower space is the driving channel. The joints of the parallel air duct flue plate structure and the prefabricated parts and the brackets are sealed with self-compacting concrete and coated with sealant to ensure sealing.

[0057] Furthermore, the fan in the ventilation room 3 is a reversible fan.

[0058] For a two-tube tunnel, the network ventilation system of this embodiment can increase the number of ventilation paths from the conventional 2 to 4, and the net area of ​​the main ventilation duct 4 can be reduced by nearly 1 / 2; for a three-tube tunnel, the network ventilation system of this embodiment can increase the number of ventilation paths from the conventional 2 to 6, and the net area of ​​the main ventilation duct 4 can be reduced by nearly 2 / 3.

[0059] Embodiment 2

[0060] This embodiment provides a design method for a tunnel network ventilation system. The network ventilation system is used for smoke exhaust. Its structure is as follows: Figure 1 As shown, the vent is provided with a smoke exhaust valve, and the ventilation room is provided with a smoke exhaust fan. The method comprises the following steps:

[0061] S1. Determine the number of parallel air ducts, spacing and specifications of smoke exhaust valves;

[0062] S2. Construct a ventilation network model based on the air leakage level of the main ventilation duct, the structural form of the smoke exhaust valve, and the sealing requirements of the connection between the smoke exhaust valve and the civil foundation;

[0063] S3, select two adjacent groups of smoke exhaust valves in the closed state and the main ventilation duct between them as the standard section, and the total air leakage of the standard section is Q n漏 Including exhaust valve leakage Q n1 And the air leakage of the main ventilation duct Q n2 , the calculation formula is as follows:

[0064] Q n1 =2·f1(P)·A1

[0065] Q n2 =f2(P)·A2

[0066] Q n漏 =Q n1 +Q n2

[0067] Where:

[0068] f1(P)——the calculation formula for the air leakage per unit area when the exhaust valve is closed. The main ventilation duct pressure P is the dependent variable of the formula, which can be calculated and determined according to the specifications or exhaust valve parameters;

[0069] A1——area of ​​a single smoke exhaust valve, m 2 ;

[0070] f2(P)——the calculation formula of air leakage in the main ventilation duct. The pressure P of the main ventilation duct is the dependent variable of the formula, which can be calculated and determined according to the specifications or construction conditions;

[0071] A2——main ventilation duct plate area of ​​standard section, m 2 .

[0072] From the above formula, it can be seen that as long as the main ventilation duct pressure P of the standard section is determined, the total air leakage Q of the standard section can be calculated. n漏 ;

[0073] Assuming that the air leakage area when the exhaust valve is closed is A0, the total air leakage volume Q of the standard section through A0 into the main ventilation duct under the action of the main ventilation duct pressure P is n漏 The relationship is as follows:

[0074]

[0075] Where:

[0076] k0——equivalent drag coefficient of standard section;

[0077] ρ——Smoke density, kg / m3 ;

[0078] A0—→ Leakage area when exhaust valve is closed, m 2 ;

[0079] The above formula can be transformed into:

[0080]

[0081] Thanks to Q n漏 =f(P), so for a specific air leakage area A0, the equivalent resistance coefficient k0 corresponding to the standard section under different main ventilation duct pressures P can be calculated. k0 can represent the main ventilation duct pressure P and the total air leakage Q of this ventilation network model. n漏 relationship;

[0082] S4. Determine the smoke exhaust volume at the open smoke exhaust valve according to the fire scale and smoke exhaust plan;

[0083] S5. Propose the net area of ​​the air duct;

[0084] S6. For multiple smoke exhaust paths, the open smoke exhaust valve is used as the starting point, and the smoke exhaust valve to the smoke exhaust fan is divided into several standard sections. According to the resistance characteristics of the ventilation network, the air volume and air pressure of each standard section in the ventilation network system are calculated in turn. The air pressure and air volume of the terminal standard section are the selection parameters of the smoke exhaust fan. The calculation formula is as follows:

[0085]

[0086]

[0087] Where: n——standard section number, n=1, 2, 3...;

[0088] P n ——wind pressure in the standard section of the terminal, Pa;

[0089] P0——wind pressure at the vent, Pa;

[0090] P n1 ——Calculate the resistance along the standard section, Pa;

[0091] P n2 ——Calculate the resistance along the standard section, Pa;

[0092] Q n ——Air volume of the standard section at the end, m 3 / s;

[0093] Q0——air volume allocated to the calculated smoke exhaust path, m 3 / s;

[0094] Q n1 ——Calculate the air leakage of the exhaust valve in the standard section when it is closed, m 3 / s;

[0095] Q n2 ——Calculate the air leakage of the main ventilation duct in the standard section, m 3 / s;

[0096] Total air leakage in the standard section Q n漏 The calculation formula can be transformed as follows:

[0097]

[0098] It can be seen that the total air leakage Q of the standard section n漏 When calculating, there is no need to calculate the air leakage of the main ventilation duct and the smoke exhaust valve separately. As long as the main ventilation duct pressure P of the standard section is obtained, combined with the k0 corresponding to the pressure P, the total air leakage Q of the standard section can be obtained. n漏 ;

[0099] S7. Design and select the type of smoke exhaust fan according to the calculation result of step S6. When the type of smoke exhaust fan meets the requirements, the proposed net area of ​​the air duct is the net area of ​​the main ventilation duct and the parallel air duct. When the type of smoke exhaust fan does not meet the requirements, return to step S5 to recalculate.

[0100] The design method of this embodiment can be used to determine the net area of ​​the main ventilation duct and the parallel ventilation duct and the selection of the smoke exhaust fan, thereby obtaining the key parameters of the network ventilation system of this embodiment.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A design method for a tunnel network ventilation system, characterized in that: The network ventilation system comprises a plurality of main ventilation ducts respectively arranged in the interval tunnels of the multi-tube tunnel, the main ventilation ducts are provided with ventilation openings, both ends of the main ventilation ducts are provided with ventilation rooms and ventilation shafts, the two ends of the main ventilation ducts are respectively connected with the ventilation rooms at both ends, and the ventilation rooms are connected with the ventilation shafts; the main ventilation ducts in two adjacent tube tunnels are connected through parallel air ducts arranged at intervals; the network ventilation system is used for smoke exhaust, and the ventilation openings are provided with smoke exhaust valves. The method comprises the following steps: S1. Determine the number of parallel air ducts, spacing and specifications of smoke exhaust valves; S2. Construct a ventilation network model based on the air leakage level of the main ventilation duct, the structural form of the smoke exhaust valve, and the sealing requirements of the connection between the smoke exhaust valve and the civil foundation; S3, select two adjacent groups of smoke exhaust valves in the closed state and the main ventilation duct between them as the standard section, and calculate the equivalent resistance coefficient corresponding to different main ventilation duct pressures under the ventilation network model; S4. Determine the smoke exhaust volume at the open smoke exhaust valve according to the fire scale and smoke exhaust plan; S5. Propose the net area of ​​the air duct; S6. For multiple smoke exhaust paths, the opened smoke exhaust valve is used as the starting point, and the area from the smoke exhaust valve to the smoke exhaust fan is divided into several standard sections. According to the resistance characteristics of the ventilation network, the air volume and air pressure of the standard section at the end of the ventilation network are calculated and determined; S7. Design and select the type of smoke exhaust fan according to the calculation result of step S6. When the type of smoke exhaust fan meets the requirements, the proposed net area of ​​the air duct is the net area of ​​the main ventilation duct and the parallel air duct. When the type of smoke exhaust fan does not meet the requirements, return to step S5 to recalculate.

2. The design method according to claim 1, characterized in that: The calculation formula of the equivalent drag coefficient of the standard section in step S3 is as follows: ； Where: ——equivalent drag coefficient of standard section; ——Smoke density, kg / m 3 ; ——Air leakage area when the exhaust valve is closed, m 2 ; ——Total air leakage in standard section, m 3 / s; ——Main ventilation duct pressure in standard section, Pa.

3. The design method according to claim 2, characterized in that: The calculation formula for determining the air volume and air pressure of the standard section at the end of the ventilation network in step S6 is as follows: ； ； Where: n——standard section number, n=1, 2, 3...; ——wind pressure in the standard section of the terminal, Pa; ——Wind pressure at the vent, Pa; ——along-the-way resistance of the standard section, Pa; ——along-the-way resistance of the standard section, Pa; ——Air volume of the standard section at the end, m 3 / s; ——The air volume allocated to the calculated smoke exhaust path, m 3 / s; ——Air leakage of smoke exhaust valve in the standard section when closed, m 3 / s; ——Air leakage of main ventilation duct in standard section, m 3 / s.

4. The design method according to claim 1, characterized in that: For subway tunnels, the interval between the parallel air ducts is no more than 1800m; for urban road tunnels, the interval between the parallel air ducts is no more than 3000m; for highway tunnels, the interval between the parallel air ducts is no more than 5000m.

5. The design method according to claim 1, characterized in that: The parallel air duct is communicated with the position where the vent is arranged on the main air duct.

6. The design method according to claim 1, characterized in that: The net area of ​​the main ventilation duct is the same as the net area of ​​the parallel air duct.

7. The design method according to claim 1, characterized in that: Two adjacent tube tunnels are connected through a transverse passage, and the transverse passage is divided into an upper space and a lower space by a flue plate. The upper space is the parallel air duct, and the lower space is a driving passage.

8. The design method according to claim 1, characterized in that: The fan in the ventilation room is a reversible fan.

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