Smoke exhaust design method for adjacent tunnel with limited boundary of shading shed

Abstract

The invention relates to the technical field of tunnel engineering, and provides a smoke exhaust design method for an adjacent tunnel with a limited boundary of a shading shed, and the method comprises the steps: obtaining the critical smoke exhaust amount of a smoke exhaust system of a target tunnel section, determining the optimal smoke blocking height of a fan-shaped smoke blocking plate according to the critical smoke exhaust amount, obtaining the rated smoke exhaust amount of each smoke exhaust assembly, and obtaining the optimal smoke blocking height of the fan-shaped smoke blocking plate; the number of smoke exhaust assemblies is determined according to the critical smoke exhaust amount and the rated smoke exhaust amount, and the smoke exhaust system is configured according to the number of the smoke exhaust assemblies and the optimal smoke blocking height of the fan-shaped smoke baffles. After the smoke exhaust system is started, the number of fans needing to be increased in the downstream tunnel can be determined according to the actual fluid channeling ratio. The safety of the downstream tunnel can be improved, the evacuation environment of the downstream tunnel can be improved, the number of fans required by the downstream tunnel can be reduced, and the engineering cost is saved. According to the obtained number of the draught fans, the evacuation environment of the downstream tunnel can be effectively improved, excessive number of the draught fans can be prevented, and the engineering cost is effectively optimized.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel engineering, in particular to a smoke exhaust design method for a tunnel adjacent to a sunshade with a limited boundary. Background Art

[0002] The fire safety issue in highway tunnels is a key issue affecting the resilience of transportation. When a fire occurs in a highway tunnel, the smoke from the fire moves forward along the tunnel under the action of the smoke exhaust fan and gradually settles, which may hinder the escape of tunnel personnel. To reduce this risk, researchers have explored a variety of smoke control methods, including air curtains, shaft smoke exhaust systems, water curtains, etc.

[0003] As highway tunnels gradually expand into mountainous areas, the number of adjacent tunnel groups on highways increases. For example, on the route from Lhasa to Shigatse in China, the longitudinal distance between the Quda Tunnel and the Badong Mountain Tunnel is only 29 meters; in the Zijinshan Tunnel Group in Hunan Province, China, the tunnel spacing is 118 meters. It is generally believed that adjacent tunnels with a tunnel spacing of less than 200 meters are called adjacent tunnels. A large number of studies have shown that there is a significant cross-flow of pollutants between adjacent tunnels. It is worth noting that due to the short connection section of adjacent tunnels, drivers will experience a sharp change in the light environment when passing through these sections, resulting in a rapid conversion of the visual light and dark adaptation process, which can easily cause visual impairment, interfere with the perception of driving information, and affect driving safety. In response to this, a sunshade is often set up in the connection section between adjacent tunnels to improve the light environment at the entrance and exit of the tunnel.

[0004] The existence of the sunshade prevents the diffusion of pollutants and fire smoke discharged from the upstream tunnel, causing pollutants and smoke to enter the downstream tunnel, affecting the ventilation and smoke exhaust of the downstream tunnel. At present, the main way to reduce this impact is to increase the number of fans in the downstream tunnel, which not only increases the project cost, but also leaves the downstream tunnel with a poor evacuation environment and safety that needs to be improved.

[0005] In addition, since the pollutant crossflow patterns and crossflow ratios between the upstream tunnel and the downstream tunnel have not yet been clarified, it is impossible to accurately determine the number of fans that should be added. Either the number of fans is insufficient, resulting in a poor evacuation environment in the downstream tunnel, or the number of fans is too large, resulting in increased project costs.

[0006] In view of this, it is necessary to propose a smoke exhaust design method for adjacent tunnels with limited boundaries of a sunshade to solve or at least alleviate the above-mentioned defects. Summary of the invention

[0007] The main purpose of the present invention is to provide a smoke exhaust design method for adjacent tunnels with restricted boundaries of a sunshade shed, so as to solve the technical problem that the existing technology reduces the impact of fire smoke by increasing the number of fans in the downstream tunnel, which not only increases the project cost, but also causes a poor evacuation environment in the downstream tunnel.

[0008] To achieve the above object, the present invention provides a smoke exhaust design method for a tunnel adjacent to a sunshade with a limited boundary, comprising the following steps:

[0009] S1, obtaining the critical smoke exhaust volume of the smoke exhaust system of the target tunnel section; wherein the target tunnel section includes an upstream tunnel section, a sunshade section and a downstream tunnel section connected in sequence, the smoke exhaust system includes a smoke exhaust component for exhausting part of the pollutants from the inside of the sunshade section to the outside of the sunshade section, and a fan-shaped smoke baffle matching the shape of the sunshade section, the smoke exhaust component and the fan-shaped smoke baffle are arranged in a one-to-one correspondence, and the fan-shaped smoke baffle is arranged downstream of the corresponding smoke exhaust component;

[0010] S2, determining the optimal smoke shielding height of the fan-shaped smoke shield according to the critical smoke exhaust volume;

[0011] S3, obtaining the rated smoke exhaust volume of each smoke exhaust component, and determining the number of smoke exhaust components according to the critical smoke exhaust volume and the rated smoke exhaust volume, and configuring the smoke exhaust system according to the number of smoke exhaust components and the optimal smoke shielding height of the fan-shaped smoke shield.

[0012] Preferably, the step S1 specifically includes the following steps:

[0013] S11, establishing a three-dimensional tunnel model for the target tunnel section;

[0014] S12, obtaining a crossflow ratio of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes; wherein the crossflow ratio is a ratio of an average concentration of a target pollutant at an entrance section of a downstream tunnel to an average concentration of a target pollutant at an exit section of an upstream tunnel, and is used to quantify the degree of crossflow of the target pollutant from the upstream tunnel to the downstream tunnel;

[0015] S13, performing curve fitting on the crossflow ratios corresponding to different smoke exhaust volumes in turn to obtain a crossflow ratio-smoke exhaust volume curve;

[0016] S14, obtaining a node smoke exhaust volume corresponding to an inflection point of the curve according to the crossflow ratio-smoke exhaust volume curve, and using the node smoke exhaust volume as the critical smoke exhaust volume.

[0017] Preferably, the step S2 specifically includes the following steps:

[0018] S21, the dimensionless critical smoke exhaust volume Q2* is determined by the formula Q2*=Q2 / (V0×S); where Q2 is the critical smoke exhaust volume, V0 is the critical wind speed for tunnel fire, and S is the cross-sectional area of ​​the tunnel;

[0019] S22, using the formula Determine the dimensionless optimal smoke shield height H max *;

[0020] S23, using formula H max =H max *×H1 determines the optimal smoke shield height H of the fan-shaped smoke shield max ; Among them, H1 is the clear height of the tunnel.

[0021] Preferably, the step S3 further includes the following steps:

[0022] S31, after starting the smoke exhaust system, fix the optimal smoke shielding height H max , obtaining the crossflow ratio R0 of the three-dimensional model of the tunnel when the smoke exhaust system is at different smoke exhaust volumes;

[0023] S32, fixing the critical smoke exhaust volume Q2, and obtaining the crossflow ratio R1 of the three-dimensional tunnel model at different smoke barrier heights H;

[0024] S33, establish R1 / R0 and H / H max Mathematical model of

[0025] S34, determining the actual crossflow ratio R* of the three-dimensional tunnel model under different actual smoke exhaust volumes and different actual smoke shielding heights according to the crossflow ratio R0 and the mathematical model;

[0026] S35, determining the number of fans that need to be added to the downstream tunnel according to the actual crossflow ratio R*.

[0027] Preferably, the step S31 of obtaining the crossflow ratio R0 of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes specifically comprises the following steps:

[0028] Using formula Determine the actual smoke exhaust volume Q3 of the smoke exhaust system; where V n is the smoke exhaust duct wind speed of the nth smoke exhaust component, S y is the cross-sectional area of ​​the smoke exhaust duct; wherein each smoke exhaust assembly comprises a smoke exhaust fan and a smoke exhaust duct, the smoke exhaust duct runs through the sunshade shed and is connected to the internal space of the sunshade shed, the smoke exhaust fan is arranged in the smoke exhaust duct to exhaust the smoke in the sunshade shed to the outside of the sunshade shed through the smoke exhaust duct;

[0029] The dimensionless critical smoke exhaust volume Q3* is determined using the formula Q3*=Q2 / Q3;

[0030] Using formula The crossflow ratio R0 of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes is determined.

[0031] Preferably, the mathematical model of step S33 is specifically:

[0032]

[0033] Preferably, the step S34 specifically includes the steps of:

[0034] Using formula Determine the actual crossflow ratio R* of the three-dimensional tunnel model under different actual smoke exhaust volumes and different actual smoke barrier heights.

[0035] Preferably, the step S35 specifically includes the steps of:

[0036] Using formula Determine the number of fans that need to be added in the downstream tunnel; Q req(co) The required air volume to dilute the cross-flow pollutants in the tunnel; Q co is the pollutant emission of the upstream tunnel, p0 is the standard atmospheric pressure, p is the atmospheric pressure at the tunnel site, T0 is the standard temperature, T is the summer temperature at the tunnel site, Qa is the air volume of a single fan, δ is the total pressure efficiency of the fan, and N is the number of fans required to be added in the downstream tunnel.

[0037] Preferably, each smoke exhaust assembly further comprises a movable smoke barrier assembly, wherein the movable smoke barrier assembly is connected to the fan-shaped smoke barrier plate, and the movable smoke barrier assembly comprises a rolling shutter door, and the unfolding area of ​​the rolling shutter door is adjustable.

[0038] Preferably, the step S35 further includes the following steps:

[0039] S41, there are no trapped persons upstream of the sunshade section, and the rolling shutter door of any smoke exhaust component is controlled to extend downward to the road surface to completely block the smoke from spreading to the downstream tunnel;

[0040] S42, when the personnel in the downstream tunnel have completed evacuation, retract the shutter door, and start all fans in the upstream tunnel and the downstream tunnel until the environment in the upstream tunnel and the downstream tunnel reaches a normal state;

[0041] S43, turn off all smoke exhaust components.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention provides a smoke exhaust design method for adjacent tunnels with restricted boundaries of sunshades, by obtaining the critical smoke exhaust volume of the smoke exhaust system of the target tunnel section, determining the optimal smoke shielding height of the fan-shaped smoke shield according to the critical smoke exhaust volume, obtaining the rated smoke exhaust volume of each smoke exhaust component, and determining the number of smoke exhaust components according to the critical smoke exhaust volume and the rated smoke exhaust volume, and configuring the smoke exhaust system according to the number of smoke exhaust components and the optimal smoke shielding height of the fan-shaped smoke shield. After starting the smoke exhaust system, the number of fans to be added in the downstream tunnel can also be determined according to the actual crossflow ratio.

[0044] The present application reduces the smoke cross-flow velocity and cross-flow ratio between tunnels, improves the evacuation environment of downstream tunnels, and improves the safety resilience of tunnels; reduces the amount of pollutants entering downstream tunnels (including fire scenarios and normal driving scenarios), reduces the number of fans required for downstream tunnels, and saves engineering costs; the number of fans determined by the obtained formula can be dynamically adjusted according to actual implementation, and the obtained number of fans can not only effectively improve the evacuation environment of downstream tunnels, but also prevent the problem of too many fans being set, which leads to high engineering costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] 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 the structures shown in these drawings without paying creative work.

[0046] Figure 1 is a schematic flow chart of a design method in one embodiment of the present invention;

[0047] Figure 2 This is a flow chart of the specific steps included in step S1 in one embodiment of the present invention;

[0048] Figure 3 A schematic cross-sectional view of a standard extra-long tunnel in one embodiment of the present invention;

[0049] Figure 4 is a schematic diagram of a crossflow ratio-smoke exhaust volume curve in one embodiment of the present invention;

[0050] Figure 5 It is a schematic diagram of a vortex formed at the top of the downstream tunnel side in one embodiment of the present invention;

[0051] Figure 6 is the optimal smoke shielding height H of the fan-shaped smoke shield in one embodiment of the present invention max Schematic diagram of the corresponding curve;

[0052] Figure 7 is a schematic diagram corresponding to Formula 2 in one embodiment of the present invention;

[0053] Figure 8 is a schematic diagram corresponding to Formula 6 in one embodiment of the present invention;

[0054] Fig. 9 is a schematic diagram corresponding to Formula 7 in one embodiment of the present invention;

[0055] Fig.10 It is a schematic elevation diagram of an application scenario diagram of a smoke exhaust assembly in one embodiment of the present invention;

[0056] Fig.11 is a top view of a smoke exhaust assembly in one embodiment of the present invention;

[0057] Fig.12 It is a side schematic diagram of an application scenario of a smoke exhaust component in one embodiment of the present invention.

[0058] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

[0059] Description of Figure Numbers:

[0060] 10. Smoke exhaust unit; 110. Smoke exhaust fan; 120. Smoke exhaust duct; 121. First vertical section; 122. Second vertical section; 123. Horizontal section; 124. Drain hole; 210. Vertical support rod; 220. Support diagonal rod; 230. Support column; 240. Fixed connecting rod; 250. Middle connecting rod; 260. Column stabilizing rod; 310. Fixed smoke barrier assembly; 311. Fan-shaped smoke barrier plate; 320. Movable smoke barrier assembly; 321. Rolling shutter door; 40. Sunshade; 50. Upstream tunnel; 60. Downstream tunnel. DETAILED DESCRIPTION

[0061] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0062] 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.

[0063] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0064] In addition, the descriptions of "right part", "middle part" and the like in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "right part" and "middle part" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0065] Please refer to the attached Figures 1 to 12 In one embodiment of the present invention, a smoke exhaust design method for a tunnel adjacent to a sunshade with a limited boundary includes the following steps:

[0066] S1, obtaining the critical smoke exhaust volume of the smoke exhaust system of the target tunnel section; wherein the target tunnel section includes an upstream tunnel section, a sunshade section and a downstream tunnel section connected in sequence, the smoke exhaust system includes a smoke exhaust component for exhausting part of the pollutants from the inside of the sunshade section to the outside of the sunshade section, and a fan-shaped smoke baffle 311 matching the shape of the sunshade section, the smoke exhaust component and the fan-shaped smoke baffle 311 are arranged in a one-to-one correspondence, and the fan-shaped smoke baffle 311 is arranged downstream of the corresponding smoke exhaust component;

[0067] As a preferred implementation, step S1 specifically includes the following steps:

[0068] S11, establishing a three-dimensional tunnel model for the target tunnel section; preferably, establishing a 1:1 three-dimensional tunnel model based on characteristic parameters such as tunnel length, cross-sectional dimensions, light-shielding shed 40 length, light-shielding shed 40 height, and fire heat release rate;

[0069] S12, obtaining a crossflow ratio of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes; wherein the crossflow ratio is a ratio of an average concentration of a target pollutant at an entrance section of the downstream tunnel 60 to an average concentration of a target pollutant at an exit section of the upstream tunnel 50, and is used to quantify the degree of crossflow of the target pollutant from the upstream tunnel 50 to the downstream tunnel 60;

[0070] S13, performing curve fitting on the crossflow ratios corresponding to different smoke exhaust volumes in turn to obtain a crossflow ratio-smoke exhaust volume curve;

[0071] S14, obtaining a node smoke exhaust volume corresponding to an inflection point of the curve according to the crossflow ratio-smoke exhaust volume curve, and using the node smoke exhaust volume as the critical smoke exhaust volume.

[0072] The specific embodiments are as follows:

[0073] The standard extra-long tunnel was selected as the research object (section size such as Figure 3 As shown in the figure, the tunnel is 3000m long, the heat release rate is 30MW, and the wind speed in the tunnel is 3m / s). The fire smoke crossflow under different smoke barrier heights and smoke exhaust volumes was studied. It was found that the CO crossflow ratio under different smoke barrier heights decreased with the increase of the smoke exhaust volume of the smoke exhaust system (downward section), and there was a stable section after reaching a certain value, such as Figure 4 As shown in the figure, the minimum smoke exhaust volume corresponding to the stable stage is the critical smoke exhaust volume Q2 = 80m 3 / s. (This is because after a fire occurs, smoke gathers under the ceiling under the action of thermal buoyancy, forming a smoke layer of a certain thickness. The smoke exhaust system draws smoke out through the smoke exhaust port, and as the amount of smoke exhaust increases, the suction force increases, and the smoke layer drawn becomes thicker. However, when the amount of smoke exhaust is large enough and the smoke layer is penetrated, the air below the smoke layer begins to be drawn, which is ineffective smoke exhaust. Therefore, there is a stable section.)

[0074] As a preferred embodiment, each smoke exhaust assembly further includes a movable smoke barrier assembly 320, wherein the movable smoke barrier assembly 320 is connected to the fan-shaped smoke barrier plate 311, and the movable smoke barrier assembly 320 includes a rolling shutter door 321, and the expansion area of ​​the rolling shutter door 321 can be adjusted.

[0075] Specifically, the fan-shaped smoke baffle 311 slows down the diffusion and spread of smoke from the upstream tunnel 50 to the downstream tunnel 60. At the same time, the fan-shaped smoke baffle 311 is arranged downstream of the smoke exhaust duct 120 to gather smoke for easy exhaust. Preferably, the fan-shaped smoke baffle 311 is made of a fire-resistant insulation board with a thickness of 3-5 mm. A stainless steel cross bar is provided at the lower edge of the fan-shaped smoke baffle 311 for fixing to the sunshade 40. Preferably, the fan-shaped smoke baffle 311 and the sunshade 40 are sealed and connected, and the fan-shaped smoke baffle 311 is arranged downstream of the smoke exhaust duct 120. The fan-shaped smoke baffle 311 is located between the top limit of the tunnel building and the sunshade 40;

[0076] The rolling shutter door 321 is placed in the smoke barrier rolling shutter box, and the maximum lower height can reach the road surface. The top of the smoke barrier rolling shutter box is fixed to a stainless steel cross bar, and it has its own rolling shutter control system. Existing mature devices can be used to control the lifting of the fireproof rolling shutter.

[0077] S2, determining the optimal smoke shielding height of the fan-shaped smoke shield 311 according to the critical smoke exhaust volume;

[0078] As a specific example, according to the numerical simulation results ( Figure 3-6 , working conditions: size as Figure 3 As shown, the length unit on the figure is cm; H = 3.5m, Q2 = 100m 3 / s, fire heat release rate 30MW), it is found that the existence of the sunshade 40 will aggravate the crossflow of pollutants between adjacent tunnels, but the device of the present invention can effectively control the crossflow of pollutants between adjacent tunnels under the action of the sunshade 40, and its fan-shaped smoke baffle 311 limits the spread of smoke, and the smoke exhaust system discharges smoke in time. The specific effects are: the temperature of the downstream tunnel 60 is reduced, the visibility of the downstream tunnel 60 is improved, and the CO crossflow ratio between tunnels is reduced. At the same time, numerical simulations with different smoke exhaust volumes and smoke barrier system heights were carried out. The results show that: under the same smoke exhaust volume, as the height of the smoke barrier system increases, the CO crossflow ratio between adjacent tunnels first decreases and then increases. There is an optimal smoke barrier height, such as Figure 6 shown.

[0079] There are two main reasons for this: (1) The fan-shaped smoke baffle 311 can only slow down and gather smoke, but cannot completely block the spread of smoke downstream. As the thickness of the gathered smoke layer increases and the smoke gradually settles (during the diffusion process, the cold and hot air are constantly entrained and heat exchanged, the smoke temperature decreases, causing the smoke to settle), the smoke will spread from the lower edge of the fan-shaped smoke baffle 311 to the downstream. As the height of the fan-shaped smoke baffle 311 increases, the lower the height of the lower edge of the fan-shaped smoke baffle 311, the lower the downstream smoke, causing more smoke to flow to the downstream tunnel 60. (2) The fan-shaped smoke baffle 311 hinders the horizontal movement of the upper hot air flow and forms a vortex at the top of the downstream side, such as Figure 5 As the height H of the fan-shaped smoke baffle 311 increases, the vortex at the top of the downstream side of the fan-shaped smoke baffle 311 increases, which is easy to disturb the smoke layer, accelerate smoke settling, and under the push of horizontal airflow, it is easier for smoke to enter the downstream tunnel 60 rather than being discharged from the gap between the sunshade shed 40 and the tunnel top.

[0080] As a preferred implementation, step S2 specifically includes the following steps:

[0081] S21, use the formula 1: Q2* = Q2 / (V0×S) to determine the dimensionless critical smoke exhaust volume Q2*; where Q2 is the critical smoke exhaust volume, unit: m 3 / s, V0 is the critical wind speed for tunnel fire, unit: m / s, S is the cross-sectional area of ​​the tunnel, unit: m 2 ;

[0082] S22, using formula 2: Determine the dimensionless optimal smoke shield height H max *;

[0083] S23, using formula 3: H max =H max *×H1 determines the optimal smoke shielding height H of the fan-shaped smoke shield 311 max ; Wherein, H1 is the clear height of the tunnel, unit: m;

[0084] It is worth noting that in order to obtain the optimal smoke barrier height H corresponding to different smoke exhaust volumes and tunnel sizes max , more working condition tests were carried out to obtain the dimensionless critical smoke exhaust volume Q2* and the dimensionless optimal smoke shield height H max * There is a correlation, such as Figure 7 shown.

[0085] S3, obtaining the rated smoke exhaust volume of each smoke exhaust component, and determining the number of smoke exhaust components according to the critical smoke exhaust volume and the rated smoke exhaust volume, and configuring the smoke exhaust system according to the number of smoke exhaust components and the optimal smoke shielding height of the fan-shaped smoke shield 311. For example, based on the fact that the sum of the smoke exhaust volumes of all smoke exhaust components must be greater than the critical smoke exhaust volume, the number of smoke exhaust components n=3 can be calculated, so three smoke exhaust components evenly spaced along the longitudinal direction of the tunnel can be configured in the sunshade section, and a fan-shaped smoke shield 311 is set at the downstream position of each smoke exhaust component.

[0086] As a preferred embodiment, the step S3 further includes the following steps:

[0087] S31, after starting the smoke exhaust system, fix the optimal smoke shielding height H max , obtaining the crossflow ratio R0 of the three-dimensional model of the tunnel when the smoke exhaust system is at different smoke exhaust volumes;

[0088] Furthermore, in step S31, obtaining the crossflow ratio R0 of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes specifically includes the following steps:

[0089] Using formula 4: Determine the actual smoke exhaust volume Q3 of the smoke exhaust system; where V n is the wind speed of the smoke exhaust duct 120 of the nth smoke exhaust component, S y is the cross-sectional area of ​​the smoke exhaust duct 120; wherein each smoke exhaust assembly includes a smoke exhaust fan 110 and a smoke exhaust duct 120, the smoke exhaust duct 120 runs through the sunshade shed 40 and communicates with the internal space of the sunshade shed 40, and the smoke exhaust fan 110 is arranged in the smoke exhaust duct 120 to exhaust the smoke in the sunshade shed 40 to the outside of the sunshade shed 40 through the smoke exhaust duct 120;

[0090] Formula 5: Q3* = Q2 / Q3 is used to determine the dimensionless critical smoke exhaust volume Q3*;

[0091] Using formula six: The crossflow ratio R0 of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes is determined.

[0092] It should be noted that in actual operation, the smoke exhaust system may be unable to provide the critical smoke exhaust volume Q2 required by the design due to a series of factors such as damage to the smoke exhaust fan 110 and reduced fan efficiency due to insufficient voltage. Therefore, it is necessary to obtain the crossflow ratio R0 of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes, so as to adjust the number of fans opened in the downstream tunnel 60.

[0093] like Figure 8 As shown in the figure, the experimental research results show that there is a correlation between the crossflow ratio R0 and the dimensionless critical smoke exhaust volume Q3*.

[0094] S32, fixing the critical smoke exhaust volume Q2, and obtaining the crossflow ratio R1 of the three-dimensional tunnel model at different smoke barrier heights H;

[0095] It is also worth noting that in actual operation, due to limitations of site conditions, the fan-shaped smoke shield 311 may not be able to provide the optimal smoke shield height H required by the design. max Therefore, by fixing the critical smoke exhaust volume Q2, the crossflow ratio R1 of the three-dimensional tunnel model at different smoke barrier heights H is obtained, thereby adjusting the number of fans opened in the downstream tunnel 60. Steps S31 and S32 both adopt the technical idea of ​​the control variable method.

[0096] S33, establish R1 / R0 and H / H max Mathematical model of

[0097] Furthermore, the mathematical model of step S33 is specifically:

[0098]

[0099] Specifically, the mathematical model of step S33, that is, formula 7, is shown in the attached Fig. 9 shown.

[0100] S34, determining the actual crossflow ratio R* of the three-dimensional tunnel model under different actual smoke exhaust volumes and different actual smoke shielding heights according to the crossflow ratio R0 and the mathematical model;

[0101] Preferably, the step S34 specifically includes the steps of:

[0102] Using formula Determine the actual crossflow ratio R* of the three-dimensional tunnel model under different actual smoke exhaust volumes and different actual smoke barrier heights.

[0103] Specifically, by combining Formula 6 and Formula 7, the function of the actual crossflow ratio R* can be obtained, namely, Formula 8.

[0104] S35, determining the number of fans that need to be added to the downstream tunnel 60 according to the actual crossflow ratio R*.

[0105] Furthermore, the step S35 specifically includes the steps of:

[0106] Using formula nine: Determine the number of fans required for the downstream tunnel 60; where Q req(co) The required air volume for diluting cross-flow pollutants in the tunnel, unit: m 3 / s,Q co The pollutant emission of the upstream tunnel 50, unit: m 3 / s, which can be obtained from the tunnel ventilation design document. p0 is the standard atmospheric pressure, unit: kN / m 2 , take 101.325kN / m 2 , p is the atmospheric pressure at the tunnel site, unit: kN / m 2 , T0 is the standard temperature, unit K, preferably 273K, T is the summer temperature of the tunnel site, unit: K, Q a is the air volume of a single fan, in m 3 / s: δ is the total pressure efficiency of the fan, which is 80% as a specific example, and N is the number of fans required to be added in the downstream tunnel 60, in units of units.

[0107] Specifically, according to Formula 10 of the prior art: And formula 11: Combining Formula 8, Formula 10, and Formula 11, we can get Formula 9.

[0108] It can be seen from the above formula that the actual number of fans N required to be added under different actual smoke exhaust volumes and actual different smoke barrier heights can be obtained through this formula. The number of fans obtained in this way can not only effectively improve the evacuation environment of the downstream tunnel 60, but also prevent the setting of too many fans, resulting in high engineering costs.

[0109] As a preferred embodiment, the step S35 further includes the following steps:

[0110] S41, when there are no trapped persons upstream of the sunshade section, the rolling shutter door 321 of any smoke exhaust assembly is controlled to extend downward to the road surface to completely block the smoke from spreading to the downstream tunnel 60; thereby, the evacuation environment of the downstream tunnel 60 can be improved and the available evacuation time of the downstream tunnel 60 can be extended.

[0111] S42, when the personnel in the downstream tunnel 60 have completed evacuation, the rolling shutter door 321 is retracted, and all fans in the upstream tunnel 50 and the downstream tunnel 60 are turned on until the environment in the upstream tunnel 50 and the downstream tunnel 60 reaches a normal state; the definition of a normal state is, for example, no fire smoke, no high temperature, and no toxic and harmful gas content is reduced to below a safe value.

[0112] S43, turn off all smoke exhaust components.

[0113] Please refer to the attached Figures 10 to 12 As a preferred embodiment, each of the smoke exhaust components includes a smoke exhaust unit 10 and a support component (not shown in the figure), wherein the smoke exhaust unit 10 includes a smoke exhaust fan 110 and a smoke exhaust duct 120, the smoke exhaust duct 120 runs through the sunshade 40 and is connected to the internal space of the sunshade 40, the smoke exhaust fan 110 is arranged in the smoke exhaust duct 120 to exhaust the smoke in the sunshade 40 to the outside of the sunshade 40 through the smoke exhaust duct 120, and the support component is used to support the smoke exhaust fan 110.

[0114] In the present application, when smoke or other pollutants appear inside the sunshade 40, the smoke exhaust fan 110 is started to work, and the smoke exhaust fan 110 sucks part of the smoke inside the sunshade 40 into the smoke exhaust duct 120, and the smoke is then exhausted to the outside of the sunshade 40 through the smoke exhaust duct 120, thereby achieving the purpose of smoke exhaust. By arranging multiple smoke exhaust devices in the sunshade 40, part of the smoke inside the sunshade 40 can be quickly and effectively discharged, thereby reducing the smoke or pollutants entering the downstream tunnel 60, improving the safety of the downstream tunnel 60, improving the evacuation environment of the downstream tunnel 60, and reducing the number of fans required for the downstream tunnel 60, saving engineering costs.

[0115] As a preferred embodiment, the smoke exhaust duct 120 includes a first vertical section 121, a second vertical section 122 and a horizontal section 123 which are sequentially connected along its extension direction, and the cross-sectional area of ​​the first vertical section 121 increases sequentially from top to bottom, and the first vertical section 121 passes through the awning 40 and is connected to the internal space of the awning 40, and the smoke exhaust fan 110 is arranged in the second vertical section 122, and the second vertical section 122 and the horizontal section 123 are L-shaped in space and are both located outside the awning 40.

[0116] Specifically, the cross-sectional area of ​​the first vertical section 121 increases from top to bottom. This design is similar to the principle of a Venturi tube, and can accelerate the flow of smoke to a certain extent. When the smoke enters the first vertical section 121 from the inside of the sunshade shed 40, the flow rate of the smoke will increase due to the gradual decrease in the cross-sectional area, thereby enhancing the smoke exhaust effect to a certain extent.

[0117] The upper part of the rhombus-shaped first vertical section 121 is connected to the L-shaped smoke exhaust duct 120 (i.e., the second vertical section 122 and the horizontal section 123). The wall material of the second vertical section 122 and the horizontal section 123 is preferably 2-3mm stainless steel, and the cross-sectional size is 1*1m. The length of the second vertical section 122 and the horizontal section 123 is 2.5m, and a 90° bend section is set between the two.

[0118] As a preferred embodiment, the support assembly includes a vertical support rod 210, a support diagonal rod 220 and a support column 230, wherein the top of the vertical support rod 210 is fixedly connected to the smoke exhaust fan 110, the high end of the support diagonal rod 220 is connected to the bottom of the vertical support rod 210, the top of the support column 230 is connected to the low end of the support diagonal rod 220, the bottom of the support column 230 is connected to the road surface, and the support column 230 is arranged between the side limit of the tunnel building and the sunshade 40.

[0119] Specifically, the vertical support rod 210 is fixedly connected to the smoke exhaust fan 110, ensuring stable support of the fan in the vertical direction; the high end of the supporting diagonal rod 220 is connected to the bottom of the vertical support rod 210, and the low end is connected to the supporting column 230, forming an oblique supporting force. The supporting column 230 serves as the foundation of the entire supporting assembly and transfers the force to the ground, ensuring the stability of the entire structure.

[0120] Preferably, the vertical support rods 210, the support diagonal rods 220 and the support columns 230 are all high-strength seamless steel pipes, which are connected to each other by welding, thereby effectively ensuring the support strength.

[0121] Preferably, the smoke exhaust fan 110 is a vertical axial flow smoke exhaust fan 110, preferably, the vertical axial flow smoke exhaust fan 110 has an outer diameter of 0.9m, and can achieve stepless flow adjustment of 0-35m3 / s, and three 2.5m high vertical support rods 210 are arranged at the bottom of the smoke exhaust fan 110, and shock-absorbing gaskets are arranged between the vertical support rods 210 and the smoke exhaust fan 110. Furthermore, the vertical support rods 210 are made of high-strength seamless steel pipes.

[0122] Furthermore, the support assembly also includes a fixed link 240 , one end of the fixed link 240 is connected to the lower end of the supporting diagonal rod 220 and the top of the supporting column 230 , and the other end of the fixed link 240 is connected to the sunshade awning 40 .

[0123] The fixed connecting rod 240 makes the connection between the supporting diagonal rod 220 and the supporting column 230 more solid, and also strengthens the connection between the sunshade 40 and the smoke exhaust device. Preferably, the fixed connecting rod 240 is made of an L-shaped steel plate. The fixed connecting rod 240 and the supporting column 230 are connected by welding.

[0124] Furthermore, it also includes a column stabilizing rod 260, which is used to reinforce the supporting column 230. Preferably, the column stabilizing rod 260 is an L-shaped steel plate.

[0125] Furthermore, there are two supporting diagonal rods 220 and two supporting columns 230, which are relatively arranged on both sides of the sunshade awning 40, and an intermediate connecting rod 250 is arranged between the two supporting diagonal rods 220 to enhance the overall structural strength.

[0126] Preferably, a first insect-proof net (not shown) is provided at the outlet of the horizontal section 123. The first insect-proof net is preferably a 20-40 mesh insect-proof net, and the main function of the first insect-proof net is to prevent insects from entering the smoke exhaust duct 120, effectively prevent insects from breeding or causing blockage in the smoke exhaust duct 120, and extend the service life of the smoke exhaust fan 110.

[0127] Preferably, the horizontal section 123 is further provided with a drainage hole 124 at one end close to the first insect-proof net, and a second insect-proof net (not shown) is provided at the outlet of the drainage hole 124. To prevent rainwater from entering the smoke exhaust duct 120 through the first insect-proof net, a drainage trough with a width of 5 cm is provided at 50 cm from the first insect-proof net, and a second insect-proof net is provided at the bottom of the drainage trough, preferably a 20-40 mesh insect-proof net.

[0128] Furthermore, the first vertical section 121 is in the shape of a prism that is small at the top and large at the bottom. The wall material of the rhombus-shaped first vertical section 121 is preferably 2-3 mm stainless steel, the cross-sectional size of the lower part of the rhombus is 3*3m, and the cross-sectional size of the upper part is 1*1m. The lower part of the rhombus-shaped first vertical section 121 is embedded in the sunshade.

[0129] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A smoke exhaust design method for a tunnel adjacent to a sunshade with limited boundaries, characterized in that: The following steps are involved: S1, obtaining the critical smoke exhaust volume of the smoke exhaust system of the target tunnel section; wherein the target tunnel section includes an upstream tunnel section, a sunshade section and a downstream tunnel section connected in sequence, the smoke exhaust system includes a smoke exhaust component for exhausting part of the pollutants from the inside of the sunshade section to the outside of the sunshade section, and a fan-shaped smoke baffle matching the shape of the sunshade section, the smoke exhaust component and the fan-shaped smoke baffle are arranged in a one-to-one correspondence, and the fan-shaped smoke baffle is arranged downstream of the corresponding smoke exhaust component; S2, determining the optimal smoke shielding height of the fan-shaped smoke shield according to the critical smoke exhaust volume; S3, obtaining the rated smoke exhaust volume of each smoke exhaust component, and determining the number of smoke exhaust components according to the critical smoke exhaust volume and the rated smoke exhaust volume, and configuring the smoke exhaust system according to the number of smoke exhaust components and the optimal smoke shielding height of the fan-shaped smoke shield.

2. The smoke exhaust design method for adjacent tunnels with limited boundaries of a sunshade according to claim 1, characterized in that: The step S1 specifically includes the following steps: S11, establishing a three-dimensional tunnel model for the target tunnel section; S12, obtaining a crossflow ratio of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes; wherein the crossflow ratio is a ratio of an average concentration of a target pollutant at an entrance section of a downstream tunnel to an average concentration of a target pollutant at an exit section of an upstream tunnel, and is used to quantify the degree of crossflow of the target pollutant from the upstream tunnel to the downstream tunnel; S13, performing curve fitting on the crossflow ratios corresponding to different smoke exhaust volumes in turn to obtain a crossflow ratio-smoke exhaust volume curve; S14, obtaining a node smoke exhaust volume corresponding to an inflection point of the curve according to the crossflow ratio-smoke exhaust volume curve, and using the node smoke exhaust volume as the critical smoke exhaust volume.

3. The smoke exhaust design method for adjacent tunnels with limited boundaries of a sunshade according to claim 2, characterized in that: The step S2 specifically includes the following steps: S21, the dimensionless critical smoke exhaust volume Q2* is determined by the formula Q2*=Q2 / (V0×S); where Q2 is the critical smoke exhaust volume, V0 is the critical wind speed for tunnel fire, and S is the cross-sectional area of ​​the tunnel; S22, using the formula Determine the dimensionless optimal smoke shield height H max *; S23, using formula H max =H max *×H1 determines the optimal smoke shield height H of the fan-shaped smoke shield max ; Among them, H1 is the clear height of the tunnel.

4. The smoke exhaust design method for a tunnel adjacent to a sunshade with limited boundaries according to claim 3, characterized in that: The step S3 further includes the following steps: S31, after starting the smoke exhaust system, fix the optimal smoke shielding height H max , obtaining the crossflow ratio R0 of the three-dimensional model of the tunnel when the smoke exhaust system is at different smoke exhaust volumes; S32, fixing the critical smoke exhaust volume Q2, and obtaining the crossflow ratio R1 of the three-dimensional tunnel model at different smoke barrier heights H; S33, establish R1 / R0 and H / H max Mathematical model of S34, determining the actual crossflow ratio R* of the three-dimensional tunnel model under different actual smoke exhaust volumes and different actual smoke shielding heights according to the crossflow ratio R0 and the mathematical model; S35, determining the number of fans that need to be added to the downstream tunnel according to the actual crossflow ratio R*.

5. The smoke exhaust design method for adjacent tunnels with limited boundaries of a sunshade according to claim 3, characterized in that: The step S31 of obtaining the crossflow ratio R0 of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes specifically includes the following steps: Using formula Determine the actual smoke exhaust volume Q3 of the smoke exhaust system; Among them, V n is the smoke exhaust duct wind speed of the nth smoke exhaust component, S y is the cross-sectional area of ​​the smoke exhaust duct; wherein each smoke exhaust assembly comprises a smoke exhaust fan and a smoke exhaust duct, the smoke exhaust duct runs through the sunshade shed and is connected to the internal space of the sunshade shed, the smoke exhaust fan is arranged in the smoke exhaust duct to exhaust the smoke in the sunshade shed to the outside of the sunshade shed through the smoke exhaust duct; The dimensionless critical smoke exhaust volume Q3* is determined using the formula Q3*=Q2 / Q3; Using formula The crossflow ratio R0 of the three-dimensional tunnel model when the smoke exhaust system is at different smoke exhaust volumes is determined.

6. The smoke exhaust design method for adjacent tunnels with limited boundaries of a sunshade according to claim 5, characterized in that: The mathematical model of step S33 is specifically:

7. The smoke exhaust design method for a tunnel adjacent to a sunshade with limited boundaries according to claim 5, characterized in that: The step S34 specifically includes the following steps: Using formula Determine the actual crossflow ratio R* of the three-dimensional tunnel model under different actual smoke exhaust volumes and different actual smoke barrier heights.

8. The smoke exhaust design method for adjacent tunnels with limited boundaries of a sunshade according to claim 7, characterized in that: The step S35 specifically includes the following steps: Using formula Determine the number of fans that need to be added in the downstream tunnel; Q req(co) The required air volume to dilute the cross-flow pollutants in the tunnel; Q co is the pollutant emission of the upstream tunnel, p0 is the standard atmospheric pressure, p is the atmospheric pressure at the tunnel site, T0 is the standard temperature, T is the summer temperature at the tunnel site, Qa is the air volume of a single fan, δ is the total pressure efficiency of the fan, and N is the number of fans required to be added in the downstream tunnel.

9. The smoke exhaust design method for a tunnel adjacent to a sunshade with limited boundaries according to claim 4, characterized in that: Each smoke exhaust assembly also includes a movable smoke barrier assembly, which is connected to the fan-shaped smoke barrier plate. The movable smoke barrier assembly includes a rolling shutter door, and the expansion area of ​​the rolling shutter door can be adjusted.

10. The smoke exhaust design method for adjacent tunnels with limited boundaries of a sunshade according to claim 9, characterized in that: The step S35 further includes the following steps: S41, there are no trapped persons upstream of the sunshade section, and the rolling shutter door of any smoke exhaust component is controlled to extend downward to the road surface to completely block the smoke from spreading to the downstream tunnel; S42, when the personnel in the downstream tunnel have completed evacuation, retract the shutter door, and start all fans in the upstream tunnel and the downstream tunnel until the environment in the upstream tunnel and the downstream tunnel reaches a normal state; S43, turn off all smoke exhaust components.

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