基于Monte-Carlo法的高速公路纵坡坡度可靠性分析

Reliability Analysis of Longitudinal Slope of Expressway Based on Monte Carlo Method

为探究保证行车安全的高速公路纵坡坡度值,引入可靠度理论,以上坡路段载重车辆运行速度降低至容许最低速度为极限平衡条件,建立纵坡坡度计算模型,并提出其可靠度功能函数。使用蒙特卡洛仿真算法,求解设计速度分别为120,100,80 km/h对应最大坡长条件下,不同坡度供给值的可靠概率,并以可靠概率为95%对应的坡度值作为推荐值。研究表明,规范值存在较大行车风险,基于可靠度理论得到的3种设计速度下的最大安全纵坡坡度推荐值分别为2.4%,3.4%,4.4%,该值可有效提升道路安全性。

The purpose of this paper is to explore the longitudinal slope value of the expressway to ensure driving safety.Firstly,a reliability theory is proposed,and a calculation model of longitudinal slope is developed on the condition that the operating speed of the heavy-duty vehicles on the uphill section is reduced to the allowable minimum speed.Based on this,the reliability function is proposed.Then,the Monte Carlo simulation algorithm is used to solve the reliability probabilities of different slope supply values under the design speed of 120,100,and 80 km/h corresponding to the maximum slope length,and the slope value corresponding to the reliability probability of 95%is used as the recommended value.The results show that there is a significant driving risk to use the value given by the Code.The road safety can be effectively improved under the recommended value of the maximum safe longitudinal slope gradients at three design speeds,which are based on the reliability theory and the values are 2.4%,3.4%,and 4.4%,respectively.