Risk Analysis Of Fire Probability In Cross-Sea Harbor Tunnel

With the increase in the length and scale of the underwater road tunnel,tunnel safety has also become an important issue.Highway tunnel fire has the characteristics of temperature rising fast?big smoke?spreading easily?difficult to evacuate?poor fire conditions?place at random?unpredictable consequences.Compared with the general land highway tunnel,the underwater road tunnel has less horizontal evacuation channel,less escape route and long escape distance.In the event of fire,it can cause human body burn,human poisoning,tunnel structure collapse,tunnel facility damage,economic loss.Therefore,it has great significance to carry out scientific analysis and evaluation of the fire risk of highway tunnel for realizing the safety target of tunnel disaster prevention and rescue system.Based on the theory of mathematical statistics,system security theory,probability theory and fuzzy mathematics theory,this thesis determines the frequency of fire in the underwater special long highway tunnel,and analyze the key influencing factors of Highway Tunnel Fire Accident,and establish the accident tree of key factors and evaluation system of highway tunnel fire,and carry on quantitative assessment of road tunnel fires.Meanwhile,numerical simulation software was used to simulate the fire exhaust failure of Mawan tunnel and the fire at design wind speed of Mawan tunnel.The main content includes several aspects:According to the frequency of fire tunneling at home and abroad,this thesis investigates the domestic special long underwater highway tunnel fire frequency,and determines the frequency of fire in the underwater special long highway tunnel.The thesis analyze the road tunnel fire with event tree,and find out the key factor for highway tunnel fire casualties:tunnel fire monitoring and fire alarm,fire control and evacuation,and establish the corresponding accident tree.Through the analysis of structural importance,determining the highway tunnel alarm system,ventilation control system and the emergency door should be focused on maintenance.Based on the theory of fuzzy mathematics,the thesis establishes a highway tunnel fire evaluation system with personnel,facilities,environment and management as the primary index,determining the Weight of Fire Risk Evaluation Index of Highway Tunnel by Analytic Hierarchy Process.The fuzzy fire risk of highway tunnel is evaluated by fuzzy mathematics method,and determining the safety of road tunnels.In the case of fire out of control,the best time for a person to escape is within 100s of the fire,it will be dangerous to leave away the fire out of 300 seconds.At the design wind speed,the flue gas is completely controlled in the lower reaches of the fire,and the ventilation of the Mawan tunnel is good.Therefore,it is a good condition to control the fire to ensure the ventilation mechanical and electrical equipment of Mawan tunnel.According to the actual engineering situation of Mawan tunnel,the fire risk of Mawan tunnel is analyzed and evaluated.Calculated by the accident tree and the event tree,refer to the mechanical and electrical status of some domestic highway tunnels,in guarantee personnel risk level is serious,and the intact rate of power supply facility is 85%and the intact rate of ventilation facility is 82%,equipment integrity rate of lighting equipment must reach more than 91%,equipment integrity rate of the fire facilities must be more than 95%,equipment integrity rate of monitoring and communication facilities must be more than 94.5%.In addition,according to the fuzzy mathematics evaluation method,the fire risk level of the Mawan tunnel is determined as "relatively safe".