CN111861168A - Highway tunnel fire risk quantitative evaluation method - Google Patents

Abstract

The invention discloses a method for quantitatively evaluating fire risks of a highway tunnel, which comprises the following steps of classifying traffic compositions in the tunnel; then respectively calculating fire risk values of all vehicle types under the reasons of vehicle faults, unintentional behaviors and intentional behaviors; respectively listing event trees of two-vehicle collision and three-vehicle collision according to a permutation and combination method; respectively calculating fire risk values under each collision condition; and comparing the maximum fire risk value under the collision condition with the fire risk values caused by vehicle faults, unintentional behaviors and intentional behaviors, and determining the scene with the maximum risk value and the corresponding fire risk value. According to the invention, the fire risk condition of the tunnel can be rapidly evaluated according to the traffic composition in the tunnel, and the fire scene with the largest risk in the tunnel can be obtained, so that a disaster prevention rescue strategy can be established in a targeted manner, and the risk is reduced. The evaluation method is uniform in calculation method, can be used for comparing risks among tunnels, and lays a foundation for building a tunnel fire risk library and an accident summary library.

Description

Highway tunnel fire risk quantitative evaluation method

Technical Field

The invention relates to the technical field of tunnel risk assessment, in particular to a highway tunnel fire risk quantitative assessment method which is suitable for fire risk assessment of urban tunnels at all levels.

Background

With the rapid development of economy and the massive construction of urban traffic tunnels, many traffic safety problems come along with the urban traffic tunnels, and tunnel fires begin to rush. 24 months 3 and 1999, 41 people die due to fire disaster when connecting the Bolang tunnel between France and Italy, 43 vehicles are burnt out, and the tunnel is opened again 3 months 11 days 3 and 2002 years after being closed 3 years; 29 th month 5 1999, the Doen tunnel in Austria had a fire, which lasted 4 hours, burned 13 people, and burned 34 vehicles; 24/10/2001, the second longest of the world's alpine santotda tunnels developed fires that caused significant injuries and losses. The tunnel has few holes connected with the outside, fire smoke is easy to fill the whole tunnel quickly, the visibility is reduced, and a large amount of harmful gases such as CO generated by incomplete combustion can threaten the personal safety of personnel in the tunnel. If a fire disaster happens to the tunnel, the difficulties of extremely difficult evacuation of people, very difficult fire extinguishing and rescue, great casualties, great property loss and the like exist in the disaster prevention and rescue and operation safety of the tunnel. The longer the tunnel, the longer the time required for vehicle evacuation, and the greater the likelihood of a secondary disaster occurring during a fire. Moreover, when the temperature of a fire scene is too high, the concrete at the arch crown of the tunnel has the danger of burning, collapsing and falling, which can make the difficulty of fire-fighting and rescue immeasurable.

Different tunnels are different in traffic composition, so that the conditions of vehicle traffic control are different, and different vehicle types have different heat release rates, so that the fire risk conditions of each tunnel are different. There is a need to establish a tunnel fire risk assessment method considering traffic composition in a tunnel so as to provide a theoretical basis for making a tunnel disaster prevention rescue strategy.

At present, most of values in the fire risk evaluation methods depend on expert evaluation, the subjectivity is high, and a uniform evaluation standard is difficult to form.

Disclosure of Invention

Based on the defects in the prior art, the invention aims to provide a method for quantitatively evaluating the fire risk of the highway tunnel, which can quickly, simply and conveniently calculate the fire risk of the tunnel and obtain a fire scene with the largest risk in the tunnel, so that a disaster prevention rescue strategy can be established in a targeted manner and the risk can be reduced.

In order to achieve the purpose, the invention adopts the following technical measures:

a highway tunnel fire risk quantitative evaluation method comprises the following steps:

s1, firstly, classifying the traffic composition in the tunnel;

s2, respectively calculating fire risk values of all vehicle types under the reasons of vehicle faults, unintentional behaviors and intentional behaviors;

S3, respectively listing event trees of two-vehicle collision and three-vehicle collision according to a permutation and combination method;

s4, respectively calculating fire risk values under each collision condition;

and S5, comparing the maximum fire risk value under the collision condition with the fire risk values caused by vehicle faults, unintentional behaviors and intentional behaviors, and determining the scene with the maximum risk value and the corresponding fire risk value.

In step S1, traffic composition is derived from the traffic volume survey data of the project traffic survey and forecast report.

Preferably, in step S2, the fire risk value for vehicle failure, unintentional behavior, and intentional behavior is calculated by the following formula:

R＝P_v×P_F×HRR_v

in the formula P_vDetermined according to the traffic composition of the project for the probability of each vehicle type appearing in the tunnel, P_FRepresenting the probability of causing a fire, HRR_vThe heat release rate of the corresponding vehicle type.

In step S4, the calculation formula of the fire risk value for the fire due to the vehicle collision is as follows:

in the formula P_vRepresenting the probability of each vehicle type appearing in the tunnel, A_vRepresenting the accident probability corresponding to each vehicle type,

representing the sum of the heat release rates of the vehicle types involved in the collision.

Compared with the prior art, the invention has the beneficial effects and advantages that:

The method has the main advantages that the fire risk condition of the tunnel can be rapidly evaluated according to the traffic composition in the tunnel, and the fire scene with the largest risk in the tunnel is obtained, so that a disaster prevention rescue strategy can be established in a targeted manner, and the risk is reduced. Meanwhile, compared with a fuzzy evaluation risk assessment method based on expert scoring, the fuzzy evaluation risk assessment method based on expert scoring has subjective factors and certain uncertainty exists among different projects, and the method is unified in calculation method, can be used for risk comparison among tunnels, and lays a foundation for building a tunnel fire risk library and an accident summary library.

Drawings

Fig. 1 is a flowchart of a fire risk quantitative evaluation method for a road tunnel according to the present invention.

FIG. 2 is an event tree for a two-vehicle collision scenario.

Fig. 3 is an event tree for a three-vehicle collision scenario.

Detailed Description

According to different reasons causing the tunnel fire, the tunnel fire can be divided into four types, namely vehicle failure, unintentional behavior, intentional behavior and collision, and the risks of the tunnel fire caused by the four types of reasons need to be calculated respectively.

The fire risk calculation method based on the statistical analysis data comprises the following steps: the following formula can be adopted for calculating the vehicle fault, the unintentional behavior and the intentional behavior:

R＝P_v×P_F×HRR_v

Wherein R represents the fire risk, P_vDetermined according to the traffic composition of the project for the probability of each vehicle type appearing in the tunnel, P_FRepresenting the probability of causing a fire, can be found by reference to the following table 1, HRR_vThe heat release rate for the corresponding vehicle type can be determined with reference to table 2.

TABLE 1 probability of fire for various reasons

Cause of fire	Breakdown of vehicle	Neglect of great intention	Intentional pilot fire
				PF	1.66E-04	3.47E-05	7.58E-05

TABLE 2 Heat Release Rate for each typical vehicle type

Vehicle model	HRR
		M	1.24
C	4.7
		B	29.7
LGV	16
		HGV	201.9

In the table, M represents a motorcycle, C represents a car, B represents a passenger car, LGV represents a light truck, and HGV represents a heavy truck.

The calculation of the fire risk value for the fire caused by the vehicle collision cause can be determined by the following formula, and it has been studied that the vehicle collision considers only the collision combination of at most three vehicle types because the fire risk value gradually decreases as the number of vehicle types involved in the collision increases.

In the formula P_vRepresenting the probability of each vehicle type appearing in the tunnel, A_vRepresenting the accident probability corresponding to each vehicle type, the values can be taken according to the table 3, 3.47 x 10^-5The probability of a fire resulting from a vehicle collision.

Representing the sum of the heat release rates of the vehicle types involved in the collision.

TABLE 3 Accident probability corresponding to each typical vehicle type

Vehicle model	Probability of accident
		M	3.08E-02
C	1.14E-02
		B	3.53E-02
LGV	7.02E-03
		HGV	2.64E-02

And (4) taking the maximum value of the risk value obtained by calculating the situation as the risk value of the tunnel, so that the design scene with the highest fire risk in the tunnel can be determined, and a theoretical basis is provided for the next ventilation and smoke exhaust design. And meanwhile, combining a risk value evaluation table to obtain the fire risk level of the tunnel.

Fig. 1 and 2 respectively list the event trees of the two-vehicle collision and the three-vehicle collision, i.e., all the collision possibilities of the two-vehicle collision and the three-vehicle collision, in the method of permutation and combination of M (motorcycle), C (car), L (light truck), H (heavy truck), and B (passenger car). Through research, the risk value is gradually reduced along with the increase of the number of collision vehicle types, so that only the collision situations of at most three vehicle types are considered. Wherein, the two-vehicle collision has 15 collision combination conditions, and the three-vehicle collision has 35 collision combination conditions.

The invention discloses a highway tunnel fire risk quantitative evaluation method, which comprises the following steps:

A. firstly, traffic compositions in the tunnel are classified, and detailed composition conditions of traffic can be obtained according to traffic volume survey data of project traffic surveys and forecast reports. There may be various vehicle types in the traffic survey report and the industrial report, and the vehicle types are classified under the MCLHB classification system. Table 4 below lists the traffic composition for a tunnel. 16.37% of motorcycle (M), 5.77% of car (C), 30.09% of passenger car (B), 31.08% of light truck (L) and 16.69% of heavy truck (H).

B. Then, fire risk values of the respective vehicle models for the reasons of vehicle failure, unintentional behavior, and intentional behavior are calculated, respectively, as shown in table 5 below. The probability of the vehicle type appearing in the tunnel in table 4 is the traffic proportion of each vehicle type in the previous step. And (3) carrying out value selection on the probability of causing the fire according to different reasons in the table I, and then multiplying the probability of the vehicle type appearing in the tunnel, the probability of causing the fire and the heat release rate of each vehicle type to obtain a product, namely the corresponding risk value.

C. Then, M (motorcycle), C (car), L (light truck), H (heavy truck) and B (passenger car) are respectively listed according to a permutation and combination method to be the event tree when two cars collide and three cars collide, namely, all collision possibility sets of the two car collision and the three car collision. Fig. 1 and 2 exhaust all possibilities in the case of a two-vehicle collision and a three-vehicle collision, respectively.

D. The risk value for each collision situation is then calculated separately. Each vehicle type firstly calculates the probability of the vehicle appearing in the tunnel multiplied by the accident probability of the corresponding vehicle type, then multiplies the product of the results of all the vehicle types by the probability of fire caused by the vehicle collision (3.47E-05), and then multiplies the sum of the heat release rates of the vehicle types participating in the collision, so as to obtain the fire risk value under the collision condition, wherein the calculation results are shown in Table 6.

E. The maximum fire risk value under the collision condition is compared with the risk values of the fire caused by vehicle faults, unintentional behaviors and intentional behavior reasons, so that the scene with the maximum risk value and the corresponding fire risk value can be determined, and the final result is shown in table 7. From the above calculations, it can be seen that the scenario with the highest risk of fire is heavy truck burning due to vehicle failure, with a risk value of 5.59E-03. The fire risk level of a Heavy Goods Vehicle (HGV) catching fire is higher than other vehicle types. The reason is that the proportion of heavy goods vehicles in the tunnel is relatively high and the heat release rate is high relative to other types of vehicles, resulting in a high overall fire risk.

F. Since the traffic composition determines the probability of each vehicle appearing in a tunnel fire, the results will vary for tunnels with different traffic compositions. Meanwhile, the method is particularly suitable for urban tunnels, can be used for comparing the fire risks of different urban tunnels, and can provide certain basis for ventilation, smoke discharge and disaster prevention rescue.

TABLE 4 traffic distribution in a tunnel

The selection of the vehicle heat release rate is based on the data given in table 2. Based on the standards, the relevant vehicle types take the values of-1.24 MW for motorcycles, 4.7MW for cars, 29.7MW for passenger cars, 16MW for light trucks and 201.9MW for heavy trucks.

TABLE 5 vehicle Fault, inadvertent, intentional fire Risk

TABLE 7 summary of risk value calculations

The invention provides a tunnel fire risk evaluation method based on traffic composition, values are objective data, and calculation results can be compared in different projects. Compared with an expert evaluation method, the method has objectivity, results among different tunnels can be compared, meanwhile, the largest risk value fire scene which cannot be obtained by the traditional method can be obtained, a direction can be provided for disaster prevention and rescue strategy formulation (traffic control and key monitoring), and the purposes of targeting and highlighting key points are achieved.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can understand that the modifications or substitutions within the technical scope of the present invention should be included in the scope of the present invention.

Claims (4)

1. A highway tunnel fire risk quantitative evaluation method is characterized by comprising the following steps:

s1, firstly, classifying the traffic composition in the tunnel;

s2, respectively calculating fire risk values of all vehicle types under the reasons of vehicle faults, unintentional behaviors and intentional behaviors;

s3, respectively listing event trees of two-vehicle collision and three-vehicle collision according to a permutation and combination method;

s4, respectively calculating fire risk values under each collision condition;

and S5, comparing the maximum fire risk value under the collision condition with the fire risk values caused by vehicle faults, unintentional behaviors and intentional behaviors, and determining the scene with the maximum risk value and the corresponding fire risk value.

2. The method for quantitatively evaluating the fire risk in the road tunnel according to claim 1, wherein in step S1, the traffic composition is obtained according to the traffic volume survey data of the project traffic survey and the forecast report.

3. The method for quantitatively evaluating the fire risk in the road tunnel according to claim 1, wherein in step S2, the fire risk value for vehicle failure, unintentional behavior and intentional behavior is calculated by using the following formula:

R＝P_v×P_F×HRR_v

in the formulaP_vDetermined according to the traffic composition of the project for the probability of each vehicle type appearing in the tunnel, P_FRepresenting the probability of causing a fire, HRR_vThe heat release rate of the corresponding vehicle type.

4. The method for quantitatively evaluating a fire risk in a road tunnel according to claim 1, wherein in step S4, the calculation formula of the fire risk value for a fire due to a vehicle collision is as follows:

in the formula P_vRepresenting the probability of each vehicle type appearing in the tunnel, A_vRepresenting the accident probability corresponding to each vehicle type,

representing the sum of the heat release rates of the vehicle types involved in the collision.

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