苍岭隧道烟囱效应分析及火灾时排烟对策

通过对山岭隧道中烟囱效应研究现状综述的基础上,利用数值分析手段对依托工程苍岭特长公路隧道中由于受高差及温差等因素影响产生的烟囱效应现象及排烟对策进行分析。研究显示,苍岭隧道的烟囱效应是明显存在的:在纵向通风条件下,单向交通时,下坡隧道(左线)全长范围和上坡隧道(右洞)出口段将产生不利影响;在隧道双向交通时,均存在不利影响。当火灾发生时烟囱效应的不利影响出现不可控制时,会造成潜在的危险。但由于苍岭隧道设计中采取了在顶部设置独立排烟道进行独立排烟的安全措施,使火灾时烟囱效应产生的危险性大大降低。

Analysis on the "Chimney Effect" and Smoke Extraction Countermeasures for Fire in Cangling Tunnel

Through summarizing the research actuality of"chimney effect"in mountain tunnel,the"chimney effect"caused by the difference in altitude and temperature in Cangling super long highway tunnel and smoke extraction countermeasures were analyzed by numerical analysis.The research indicates that"chimney effect"is obvious in Cangling tunnel:when the ventilation is longitudinal and the traffic is one-way,"chimney effect"can bring advantage to the right tunnel and disadvantage to the left and exit of right;when the traffic is two-way, disadvantage of"chimney effect"can be brought in whole tunnel:while the disadvantage of it is out of control,it would lead to latent danger in fire.Independent smoke extraction passages at the top of secondary lining can effectually control the influence of"chimney effect"and the danger can be greatly reduced.