论文部分内容阅读
隧道通风需风量确定是公路隧道通风中的关键技术问题。对《公路隧道通风照明设计规范JTJ 026.1—1999》中的需风量计算进行了讨论,从交通工程的基本理论角度分析了车密度系数概念的不合理性和取值的不科学性。分析表明:单位时间内交通量是唯一决定需风量的变量,《规范》引入车密度系数是表象,其本质作用是修正设计交通量。因此,研究车密度系数的取值的本质是研究如何修正不同工况下交通量,也即研究不同速度下的交通量的取值。在分析交通流中流量—密度—速度关系的基础上,提出了一种基于交通流基本图模型的改进的隧道通风计算中车密度系数的取值办法,并以Greenshields线性速度—密度模型为例说明了在实际需风量计算中如何合理正确计算车密度系数。
Tunnel ventilation to determine the amount of wind tunnel ventilation is the key technical issues. Air demand calculation in “Highway Tunnel Lighting Lighting Design Specification JTJ 026.1-1999” is discussed. From the basic theory of traffic engineering, the irrationality of car density coefficient concept and unscientific value are analyzed. The analysis shows that the traffic volume per unit time is the only variable that determines the amount of air required, and the introduction of the vehicle density factor in the “Specification” is an appearance, whose essential effect is to correct the design traffic volume. Therefore, the essence of the study of the value of the vehicle density coefficient is to study how to correct the traffic under different conditions, that is, to study the traffic value under different speeds. Based on the analysis of the relationship between flow rate, density and velocity in traffic flow, a method based on traffic flow basic graph model is proposed to improve the vehicle density coefficient in tunnel ventilation calculation. Taking Greenshields linear velocity-density model as an example Explain how to calculate the car density coefficient reasonably correctly in the actual air volume calculation.