高速公路小半径平曲线超高可靠性设计

Reliability Design of Superelevation on Expressway Small Radius Horizontal Curve

针对高速公路设计中超高的取值进行研究,在现行规范有关规定的基础上,以汽车在平曲线超高处行车稳定性作为约束,改进超高计算模型;并引入可靠度理论,基于该模型构建超高可靠度功能函数,对车辆运行速度、车辆转弯半径、横向力系数等相关参数进行统计并分析其分布规律,并采用失效概率来描述超高设计的可靠程度.参考《公路工程结构可靠度设计统一标准》中高速公路对应安全等级的可靠度要求,计算不同设计速度下最大安全超高取值.结果表明,在相应极限最小半径处取8%作为最大超高,其失效概率较大即安全性较低;通过以满足一级安全等级条件的目标可靠度反算,推荐最大超高值取6%,具有较高的道路安全可靠性.

Aiming at the problem of superelevation value in the expressway design, the calculation model of the superelevation was improved with the stability of the vehicle traveling at the superelevation of the horizontal curve as the constraint, on the basis of the relevant provisions of the current code. The reliability theory was introduced to construct the superelevation reliability function. The relevant parameters such as vehicle running speed, vehicle turning radius, lateral force coefficient and so on were statistically analyzed and their distribution laws were analyzed. The failure probability was used to describe the reliability degree of the superelevation design. According to the reliability requirements of the corresponding safety grades of expressways in the Unified Standard for Reliability Design of Highway Engineering Structures, the maximum safe superelevation values at different design speeds were calculated. The research results show that if 8% is taken as the maximum superelevation value at the corresponding limit minimum radius, the failure probability is higher and the safety is lower. Through inverse calculation with the target reliability satisfying the first-class safety level condition, the recommended maximum superelevation value is 6%, which has higher road safety reliability.