基于交通流特征的高海拔隧道通风能效研究

Study on Ventilation Energy Efficiency in High-altitude Tunnels Based on Traffic Flow Characteristics

为了研究高海拔地区公路隧道车辆污染物排放特性与机械通风系统通风效率,选择乌尉高速天山胜利隧道隧址地区,针对3种典型柴油车车型进行烟尘排放现场试验,建立以车型、纵坡、车速、海拔等参数为输入的柴油车单车烟尘排放量预测随机森林模型,分析单车烟尘排放量实测值与《细则》计算值的相关性,并采用蒙特卡罗法研究隧道交通流特征参数对交通风增压效率与机械通风升压力的影响规律。结果表明:基于随机森林建立的柴油车单车烟尘排放量预测模型具有良好的预测精度,测试集的均方根误差为0.2513;单车烟尘排放量实测值小于《细则》计算值,二者在车速小于70 km/h时呈高度线性相关;隧道所需机械通风升压力随混合车型交通量增加呈线性增加,交通风增压效率随交通量的增加呈指数减小,随单车烟尘排放量的增加而减小;影响单车烟尘排放量实测值的主次顺序为纵坡>车型>车速>海拔高度,因此在高海拔地区公路隧道设计中应适当控制纵坡。

To study the vehicle pollutant emission characteristics and the ventilation efficiency of mechanical venti⁃lation system in high-altitude road tunnels,an on-site smoke emission test was conducted on three types of diesel vehicles in the Tianshan Shengli Tunnel on the Urumqi-Yuli Highway.A random forest model was established to predict the smoke emission of single diesel vehicle based on parameters such as vehicle model,longitudinal gradient,speed,and altitude.The correlation between the measured values of single-vehicle smoke emission and the calculated values from the Guidelines for Design of Ventilation of Highway Tunnels was analyzed.The Monte Carlo method was used to study the impact of tunnel traffic flow characteristic parameters on traffic wind-induced boosting efficiency and mechanical ventilation pressure.The results show that the random forest model has good predictive accuracy for single-vehicle smoke emissions,with a root mean square error of 0.2513 in the test set.The measured single-vehi⁃cle smoke emissions are lower than the calculated values from the"Guidelines,"and they are highly linearly correlated when the speed is less than 70 km/h.The required mechanical ventilation boost pressure in the tunnel increases lin⁃early with the increase in mixed vehicle traffic flow,while the traffic wind boost efficiency decreases exponentially with the increase in traffic flow and decreases with the increase in single-vehicle smoke emissions.The primary in⁃fluencing factors of single-vehicle smoke emissions in descending order are the longitudinal gradient,vehicle model,speed,and altitude.Therefore,the longitudinal gradient should be appropriately controlled in the design of high-al⁃titude road tunnels.