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目前设计任何等级的公路,都采用适用于各种地形的统一技术标准。考虑山岭区道路所不同于平原区、丘陵区道路的地方,是在于平面上有很多的弯道以及有很多地段具有最大坡度,因而必须注意去适应这些山岭区的特点,使某些技术标准更为切合实际。山岭区最重要的标准之一是圆曲线最小半径。这种半径用下式来计算: R_(最小)=V~2/(127(φ_2+i_B))公尺式中:V——汽车速度,公里/小时; φ_2——车轮与路面的横向粘着系数; i_B——超高坡度。在山区道路上所能达到的速度,是由汽车的动力特性、道路纵坡、滚动阻力系数等等来决定的。图1表示出苏联一般的汽车最大行车速度与纵坡的关系。根据这个图和前述的公式,计算出圆曲线最小半径与道路纵坡的关系。在计算中采用φ_2=0.16,i_B=0.06。使用图2中的线图,就可能根据汽车行驶的实际情况为山区公路选择出圆曲线最小半径。用这种线图总是能使圆曲线半径比全苏标准中所规定的半径小些。在全苏标准中,只考虑了等级而不考虑地形;因此,根据所
At present, any grade of highway is designed with uniform technical standards applicable to various terrains. Considering that the roads in the mountain areas differ from those in the plain areas and the hilly areas is that there are many curves in the plane and the maximum gradient in many locations. Therefore, care must be taken to adapt to the characteristics of these mountain areas so that certain technical standards To be realistic. One of the most important criteria in mountainous areas is the smallest radius of a circular curve. This radius is calculated using the following formula: R_ (min) = V ~ 2 / (127 (φ_2 + i_B)) In meters: V - vehicle speed, km / h; Coefficient; i_B - Very high grade. The speed that can be achieved on the mountain roads is determined by the dynamic characteristics of the car, the road longitudinal slope, the rolling resistance coefficient and so on. Figure 1 shows the relationship between the maximum driving speed of the Soviet Union and the longitudinal slope. According to this figure and the aforementioned formula, calculate the minimum radius of the circular curve and the road longitudinal slope. Φ_2 = 0.16 and i_B = 0.06 are used in the calculation. Using the line graph in Figure 2, it is possible to choose the smallest radius of the circular curve for mountainous roads based on the actual driving conditions of the car. With this kind of line graph, it is always possible to make the radius of the circular curve smaller than the one specified in the All-Soviet standard. In the All-Soviet standard, only rankings are taken into account regardless of the terrain; therefore, according to