山区高速公路车辆下行最大纵坡及坡长限制分析

The Maximum Longitudinal Slope and Its Length of Mountain-expressway under the Condition of Vehicle′s Driving Down

山区高速公路建设中 ,路线最大纵坡与工程量、工程造价的矛盾十分突出 ,若严格执行标准会出现大量高填、深挖路基、长大桥梁及隧道。从车辆动力学角度对山区高速公路车辆下行的最大纵坡和坡长进行了分析 ,提出了下行理想最大纵坡、一般最大纵坡、极限最大纵坡和坡长限制分析值 ,供公路设计人员及标准修订时参考。

In the construction of expressway in mountain area, the contradiction of the maximum longitudinal slope with engineering's volume and cost is very prominent. If the construction standard was executed strictly, the engineering volume of high fill and deep excavation will be very big, many long span bridges and tunnels must be constructed from the point of vehicle dynamics, and the maximum longitudinal slope and its length of mountain expressway under the condition of vehicle's driving down are analyzed. The concepts of ideal maximum longitudinal slope, general maximum longitudinal slope and the limitation maximum longitudinal slope are put forward. And their length is determined to provide a reference for highway designer.