基于能量守恒原理的公路线形安全性评价

Safety evaluation of road alignment based on energy conservation law

为了评价平纵线形对山区高等级公路安全性的影响,根据能量守恒原理,分析了汽车在下坡路段行驶过程中,纵坡坡度、纵坡坡长及平曲线半径对汽车制动系统温度升高的影响。以某山区高速公路下坡路段为例,研究了公路线形与事故发生率的关系。分析结果表明:汽车稳定车速行驶的临界坡度会随传动比和车速的升高而增大;公路的安全性会随平均纵坡坡度和坡长乘积的增加而降低;较小的平曲线半径将有利于提高汽车发动机辅助制动的效能,有利于公路安全性的提高;较大的平曲线半径方差将会增加汽车行车制动器的使用频率,降低公路的安全性。

In order to estimate the influences of horizontal and vertical alignments on the safety of high classified highway in mountain area,based on energy conservation law,the influences of longitudinal gradient,gradient length and horizontal curve radius on the temperature rise of brake system were analyzed when vehicle ran downhill.Taking example for a downhill section in mountain area,the relationship between highway alignments and accident rates was validated.Analysis result indicates that when vehicle runs stably the critical gradient increases with the increases of transmission ratio and vehicle speed. Highway safety decreases with the increase of the product between average gradient and gradient length. Because the lesser curve radius can enhance the ability of engine brake, highway safety is improved. The larger mean square error of curve radius may increase the use frequency of vehicle brake, therefore, highway safety will be reduced. 2 tabs, 3 figs, 7 refs.