间隔时间对竖井型城市隧道正常交通污染状况的影响研究

Influence of Interval Time on Pollution Condition in Urban Tunnel with Shafts under Normal Traffic

为了探究隧道内车辆运动状况对竖井型城市隧道正常交通污染状况的影响,定义了表征车速和车距共同作用的间隔时间,并利用理论分析和模型试验的方法,对不同间隔时间条件下隧道和竖井速度分布和污染物浓度分布进行了研究。通过对正常交通工况下隧道的排污理论和隧道模型相似理论的分析,明确了污染物浓度分布规律与间隔时间的关联性,得到模型搭建的几何、速度以及动力相似条件。试验共设计了间隔时间分别为0.4s、0.5s、0.65s和0.8125s四组试验方案,结果表明,隧道内污染物浓度与间隔时间成反比,间隔时间越大,污染物浓度越低。因此,通过合理控制隧道内的车速和车距,能有效降低隧道内整体污染物浓度,对推动自然通风城市隧道的发展具有重要意义。

To explore the influence of tunnel vehicle movement state on pollution condition in urban tunnel with shafts under normal traffic, the interval time was defined which characterize the interaction of speed and distance, and by using the method of theoretical analysis and model test, speed distribution and pollutant concentration in tunnel and shafts under different interval time was investigated. Through analyzing theories of pollutant evacuation and model similarity under normal traffic, relationship between distribution regulation of pollutant concentration and interval time was cleared, similarity conditions of geometric, kinematic and dynamic which is necessary for model constructing was acquired. Four experimental schemes were designed, the interval time respectively were 0.4s, 0.5s, 0.65s and 0.8125s. The results showed that tunnel pollutant concentration is inversely proportional to the time interval, the greater the time interval, the lower the concentration of pollutant concentration. Therefore, through the reasonable control of the tunnel speed and distance, can the pollutant concentration allover the tunnel reduce effectively, which has a great significance to promote the development of the natural ventilation urban tunnel.