【摘要】 为了给城市地下交通联系隧道(UTLT)防排烟系统设计和人员应急救援提供参考依据,以重庆某UTLT二期工程一段主隧道为例,开展全尺寸火灾试验,探讨了横向排烟方案的烟控效果,并验证了Alpert顶棚最高温升衰减模型。结果表明,UTLT主隧道段采用横向排烟方案,当防烟分区长度为120 m时,采用的排烟量设计方法是合理的。当隧道为上坡时,最有利的烟气控制模式为同时开启着火分区及下游相邻分区的排烟系统和与排烟分区紧邻的上、下游两个分区的补风系统。隧道顶部烟气最高温升衰减规律为:下游距火源无量纲距离r/H<0.57及上游部分,呈指数衰减;下游距火源无量纲距离r/H>0.57部分,呈幂函数衰减,且衰减程度与排烟方案有关。更多还原

【Abstract】 The present study aims to provide a reference to the smoke control system design as well as a theoretical basis for the emergency rescue service.To achieve the goal,we have done a full-scale experiment in an urban traffic link tunnel(UTLT) in Chongqing,a municipality in the south-west China,with a discussion on the different transverse ventilation modes and ways for performance.In proceeding with our study,we have done the test of the maximal gas temperature by the Alpert’s prediction model under the tunnel ceiling.The results of our test indicate that the maximum length of the smoke diffusion tends to be 237 m,whereas the actual control capability has been designed within the limit of 300 m.Therefore,the design method of the smoke control zone partition with 120 m and the calculation method of exhaust smoke volume is reasonable for the present transverse ventilation project.The smoke diffusing velocity is less than the personnel evacuation speed and under a reasonable extraction mode,the temperature at the height of 2.2 m could be controlled under 60 ℃,for it is the demand of evacuation to be satisfied for.But,whenever a fire would occur in the uphill tunnel designed with the transverse ventilation system,it should require that the mechanical ventilation systems in the fired zone and the adjacent zone in the downstream should begin to work direction in the function of exhaust systems while the two extended zones near the two smoke exhaust zones are to be activated as the air supply systems.In addition,it is demanded that the distribution of the smoke temperature under the tunnel ceiling in the longitudinal direction should be working as efficiently as an exponential function,whose dimensionless distance has to be less than 0.57 in downstream areas and in all their upstream areas.Though it can be fitted by a power function,when the dimensionless distance is larger than 0.57,and the temperature decreasing speed is related to the exhaust scheme.Thus,finally,the Alpert’s prediction model for the maximal gas temperature under the ceiling should be made fit for natural extraction,but it may not be in accord with the situations with slope and mechanical ventilation systems.更多还原