公路转弯段线形指标对混凝土护栏安全性能的影响

Influence of Alignment Indexes of Highway Turning Section on Safety Performance of Concrete Guardrail

公路转弯段的线形设计指标对护栏的安全性能有重要影响。文中基于路侧安全领域广泛使用的有限元软件LS-DYNA,通过模拟和实车试验对比验证模型的有效性,建立货车与混凝土护栏复杂碰撞试验模型,模拟计算得到车辆碰撞护栏的详细动画,作为平曲线路段上护栏安全性能的直观感受,将行车道半径、路面超高、车辆速度作为变量,研究和量化主要线形指标对混凝土护栏安全性能的影响。结果表明:道路半径接近与设计速度对应的极限最小半径时,车辆的翻滚角增大,车辆易碰撞护栏发生侧翻;行车道路面超高6%为混凝土护栏安全性能的临界点,采用大于6%的超高会使车辆沿护栏迎撞面爬坡跃升的高度增加,车辆更容易发生侧翻,设计时应避免大超高(6%以上)和小半径极值的组合;在曲线路段,碰撞速度对护栏安全性能的影响明显,整体式货车车速达90 km/h后,发生侧翻的风险明显增加。文中研究成果可为道路曲线路段路侧的线形安全设计提供理论基础。

The alignment design indexes of highway turning section have important influences on the safety performance of guardrail.In this paper,based on the finite element software LS-DYNA widely used in the field of highway side safety,a complex collision test model of truck and concrete guardrail is established,and simulation and vehicle tests are performed to comparatively verify the effectiveness of the model.Detailed animation describing the collision of vehicle to guardrail is obtained by simulation,which directly exhibits the safety performance of the guardrail in flat curve section.Then,the traffic lane radius,the superelevation value and the vehicle speed are used as variables to investigate and quantify the influence of main alignment indexes on the safety performance of concrete guardrail.The results show that,when the traffic lane radius is close to the ultimate minimum radius corresponding to the design velocity,the roll-over-angle of the vehicle increases,and the vehicle easily crashes to the guardrail and rolls over;that a superelevation value of 6%of the traffic lane is the critical point for the safety performance of concrete guardrail;that when the superelevation value is more than 6%,the height of the vehicle climbing along the collision surface of the guardrail may increase,and the vehicle is more likely to roll over,so that the combination of large superelevation(above 6%)and small ultimate minimum radius should be avoided during the highway design;and that,on the curve section,the collision speed has a significant impact on the safety performance of guardrail.For the integral van,the risk of rollovers significantly increases when the vehicle speed reaches 90 km/h.This research lays a theoretical foundation for the alignment safety design of highway curve sections.