顶部集中排烟盾构隧道结构防火保护及关键参数研究

Study on fire protection and key parameters of top centralized smoke exhaust shield tunnel structure

依托江阴靖江长江隧道开展了盾构衬砌管片抗火性能数值模拟及烟道板耐火性能试验,提出了一种新的顶部集中排烟盾构隧道结构防火保护策略。建议行车道层管片采用防火材料进行防护,烟道层拱顶部位管片采用混凝土内衬进行通长保护,烟道板不需进行防火保护。盾构管片模拟结果表明,当管片防火保护层等效热阻大于0.10℃∙m2/W时,管片耐火极限大于2.0 h;烟道板耐火性能试验表明,无防火保护烟道板构件在RABT升温曲线作用下,跨中挠度小于允许极限挠度,耐火极限大于2.0 h。模拟和试验结果表明,这种顶部集中排烟盾构隧道结构防火保护策略安全可行。

The numerical simulation of duct piece fire protection and the fire resistance experiment of flue plate were carried out based on Jiangyin Jingjiang Yangtze River Tunnel,and a new structural fire protection strategy was proposed.It is suggested that the shield section of pavement segments should be protected,and all the shield section of smoke pipe should be protected by concrete lining.However,no fire protection is required for flue sheet.The numerical simulation results of duct piece showed that when the equivalent thermal resistance of the fire protection layer is greater than 0.10℃∙m2/W,the fire resistance limit of duct piece exceeds 2.0 h.The fire test results of flue sheet showed that under the action of RABT heating curve,the mid-span deflection of non-fire protection flue sheet is smaller than the fire resistance limit deflection,and the fire resistance limit exceeds 2.0 h.The results of simulation and experiments showed that this new fire protection strategy of the top centralized smoke exhaust shield tunnel structure is safe and feasible.