山区双车道公路路线设计车型分类标准

Design Vehicles Classification Criteria for Mountain Terrain Two-lane Highway Geometric Design

为研究建立公路路线设计标准车型,通过对西部山区双车道公路的实地交通调查,并结合我国在用车型统计,建立了各类营运车辆车型参数数据库;在详细统计分析现有车型的尺寸、载质量和功率质量比分布规律的基础上,以满足85%的车型外廓尺寸和载质量为标准,采用双因素聚类分析方法对各种车型的功率质量比进行聚类分层计算,根据外廓尺寸相近的原则进行归并后,提出了山区公路路线设计车型的小型车、大型车外廓尺寸分类标准。在此分类基础上,研究了用于公路纵断面设计的载重汽车动力性能标准,通过大量实地观测资料和统计分析,提出了载重汽车上坡动力性能曲线,建立了速度折减量与坡度、坡长之间的关系曲线,以速度折减量作为公路纵坡和坡长的设计关键指标。

On the purpose of determine the standard vehicle types for highway geometric design, the database of various commercial vehicle types was established based on the survey of two-lane mountain roads in western China and domestic servicing vehicle types. The distribution of vehicle dimension, load weight, and power-mass ratio were calculated in order to represent 85% of vehicle characteristics including dimension and load capacity. Vehicle powermass ratio cluster analysis was achieved applying two-factor cluster analysis method. Afterwards, the vehicle classification criterion of passenger cars and trucks for mountainous terrain highway geometric design was determined after combination of vehicle types based on similar dimension value rules. Accordingly, research on heavy goods vehicle dynamic performance criterion for vertical alignment design was made. Upgrading performance curve and relationship of gradient, slope length with speed reduction were also established. Speed reduction can be regarded as the critical measure for vertical grade and slope length design in the future.