山区高速公路长距离连续升坡路段纵坡设计研究

Research on the combinated longitudinal-grade design of the long-distance continuous-upgrade section in mountain expressway

在总结山区长距离连续升坡路段纵断面线形特性的基础上,提出了由一个缓坡和一个陡坡组成的纵坡组合单元概念.针对纵坡组合单元,应用汽车行驶理论,建立了载重汽车在连续升坡路段上行驶时的速度、坡度及坡长间的理论模型和简化模型,并通过对两类模型的应用分析及陡坡上货车最低行驶速度的讨论,结合实例比较了简化模型的计算精度.通过对简化模型的应用分析,获得了纵坡组合单元纵坡设计指标的建议值,即:对于中型货车,在纵坡组合单元中当陡坡值id≤4.25%时,不管缓坡(<3%)如何与它组合,都能以不低于50km·h-1的速度驶完陡坡段;对于重型货车,在纵坡组合单元中陡坡值不应大于3.0%,否则,不能保证最低车速50km·h-1.

At the conculsion of this paper,based on summing up continuous long-distance mountain expressway slope linear characteristics of longitudinal sections,a combination unit of longitudinal consisting gentle slope and steep slope was introduced.With the theory of the ride dynamics,the theoretical model and simplified model was established according to truck speed,gradient and slope length on the section of expressway.Subsequently,through the application of two types of model analysis and trucks on steep slopes on the discussion of the lowest speed,example of two types of model campared the calculation accuracy of simplified model.Through the application of the simplify model,obtained the recommended value of the grade combination unit：for medium-sized trucks,combination units in the grade steep when the value of id ≤ 4.25%,regardless of the gentle slope（3%）,how to mix with it,can not less than 50 km·h-1 speed driving End steep section;for heavy trucks,combination units on steep slopes in the grade value should not exceed 3.0%,otherwise it is impossible to guarantee minimum speed of 50 km·h-1.