公路缓和曲线长度的合理取值分析  

Analysis on Reasonable Value of Highway Transition Curve Length

作　　者：富志鹏[1] 任春宁 张腾 张江洪[1] 林宣财[1] FU Zhi-peng;REN Chun-ning;ZHANG Teng;ZHANG Jiang-hong;LIN Xuan-cai(CCCC First Highway Consultants Co.,Ltd.,Xi’an,Shaanxi 710075,China)

机构地区：[1]中交第一公路勘察设计研究院有限公司,陕西西安710075

出　　处：《公路交通科技》2024年第5期44-53,共10页Journal of Highway and Transportation Research and Development

基　　金：中交第一公路勘察设计研究院科技创新基金项目(KCJJ2018-05)。

摘　　要：为给车辆由直线(圆曲线)驶入圆曲线(直线)提供合理的路径长度,确保驾驶员能以安全、舒适、自然的状态驶入目标曲线单元,通过对现行路线规范中缓和曲线长度取值规定的合理性分析,发现回旋线参数取值规定易存在曲线单元间长度分配均匀、取值长度过长、不易与地形地物相协调等问题。结合美国《绿皮书》对缓和曲线取值的相关规定,从汽车行驶轨迹、缓和曲线偏移值特征及超高过渡等方面对缓和曲线长度取值进行理论分析研究。结果表明:在设计速度一定的情况下,随着圆曲线半径的增加,缓和曲线长度取值应随之减小;随着设计速度的增加,缓和曲线长度取值也应随之增加,但增加值较小,可忽略不计;在设计速度和圆曲线半径均相同的情况下,随着缓和曲线长度的增加,驾驶员判断前方平曲线的曲率半径偏小,易驶入临近车道,不利于交通安全。另外,根据缓和曲线偏移值特征及超高过渡所需长度研究发现,通过控制缓和曲线偏移值1 m、缓和曲线长度200 m范围,圆曲线半径与缓和曲线之间的变化关系较为稳定,符合车辆行驶轨迹,基本满足超高过渡段设置的要求。经计算得出当圆曲线半径大于1666 m时,缓和曲线长度宜随圆曲半径的增大而减短。To provide a reasonable length for vehicles to move from a straight line(circular curve)to circular curve(straight line),and ensure drivers driving into the target curve at a safe,comfortable and natural state,the study analyzes the rationality of specification values of transition curve length in the current route specification.It is found that the length distribution among curve units is uniform,the length is too long,and it is not easy to coordinate with terrain and features.Combining with the relevant provisions of AASHTO on the value of transition curve,the value of transition curve length is theoretically analyzed and studied from the aspects of driving track,offset value of transition curve,and superelevation transition.The result indicates that the transition curve length decreases with the increase of circular curve radius when the design speed is fixed.With the increase of design speed,the transition curve length should also increase,but the increase value is small and can be ignored.When the design speed and circular curve radius are the same,with the increase of transition curve length,drivers would judge that the curvature radius of flat curve ahead is small.It is easy to enter the adjacent lane,which is not conducive to traffic safety.In addition,according to the study on offset value of transition curve and the length required for superelevation transition,it is found that by controlling the offset value of relaxation curve to 1 m and the length of relaxation curve to 200 m,the changing relationship between circular curve radius and transition curve is relatively stable,which is in line with the driving trajectory,and basically meets the requirements for setting superelevation transition segments.When the circular curve radius is greater than 1666 m,the length of relaxation curve should be shortened with the increase of circular curve radius.

关 键 词：道路工程 缓和曲线长度 理论分析 行驶轨迹 回旋线偏移值 超高过渡段长度 

分 类 号：U412.33[交通运输工程—道路与铁道工程]