基于胎路复杂接触效应的凝冰沥青路面抗滑特性研究

In humid mountain areas of China, glazed ice will be easily appeared in the road surface in winter. Water film which is frozen by atmospheric moisture on the glazed ice makes the pavement surface loss of friction completely. The original pavement surface sliding measures almost lose efficacy, and the friction coefficient between tyres and pavement surface reduces rapidly. This will easily cause the vehicle slipped during the driving and bring about traffic accidents, especially on the special and high risk road section such as curve, tunnel exit and entrance or long straight longitudinal gradient. Through the indoor small model test, distributing rules of the friction between tyres and the ice surface will be actually measured in this project. Considering the transient coupling effect of non-complete contact status between tyres and road surface, and solving the real dynamic load effect which is caused by the vehicle suspension and pavement surface roughness, numerical analysis model of transient contacting friction between tyres and pavement surface is established,the interaction mechanical characteristics between tyres and pavement surface while driving on the ice pavement surface and the mechanical response index of skid resistance property are analyzed. And then, the slipping mechanical mechanism during the vehicle braking, driving, cornering and turning on the glazed ice conditions is discussed. According to the mechanics analysis results and the testing results of pavenent surface friction, the attenuation model of skid resistance property of glazed ice pavement is established. The researching result of this project will be the foundation for improving anti-sliding performance of glazed ice pavement and considering skid resistance index during asphalt pavement design revision in China.

我国潮湿山区公路路面冬季易形成凝冰，大气水分在凝冰上凝结的水膜使得路表完全丧失摩擦力，路面原有抗滑措施几乎失效，轮胎和路面间摩擦系数迅速降低，尤其在弯道、隧道出入口、长大纵坡等特殊高危路段，容易导致车辆行驶过程中产生滑移，危及行车安全。本项目拟通过室内小型模型试验实测轮胎与凝冰路面间摩擦力分布规律，考虑轮胎路面间非完全接触状态的瞬态耦合作用，求解车辆悬架和路面的不平度引起的车身对轮胎的真实动荷载作用，建立车辆与路面瞬态接触摩擦动力学数值分析模型，研究凝冰路面上车辆滑移时轮胎路面间相互作用受力特性和影响路面抗滑性能的力学响应指标，分析凝冰条件下高危路段沥青路面抗滑力学机理，根据力学分析结果和路面摩擦力实测结果建立路面抗滑性能衰减模型，为提高凝冰路面抗滑性能和我国抗滑沥青路面设计方法修订奠定基础。

利用有限元软件ANSYS/LS-DYNA建立了轮胎路面复杂接触效应的有限元模型，结合结构动力学原理和Lagrange原理推导了不同路面条件下车身对轮胎的动态作用力计算模型，借助MATLAB/Simulink工具求解了车身对轮胎的动态作用力。利用ANSYS/LS-DYNA研究了轮胎在六种道路线形、五种摩擦条件下的运动规律，分析了各种路面的抗滑性能发展变化特性以及动荷载作用下的动力响应规律。结果表明：轮胎在凝冰条件下的运动速度和动能的降低速度和幅度都明显的小于在正常干燥路面的降低速度和幅度。凝冰条件下胎面摩擦力明显小于正常干燥路面的胎面摩擦力，制动距离则大于正常干燥路面的制动距离，充分说明路面凝冰对路面抗滑性能影响显著。凝冰沥青路面路表竖向应力和轮胎经过前路表水平剪应力均大于正常干燥路面,路表弯沉、轮胎经过后路表水平剪应力以及沿路面深度方向最大竖向应力、最大横向拉应力、最大横向拉应变和最大水平剪应力均小于正常干燥路面。凝冰沥青路面摩擦系数不仅影响路面抗滑性能而且影响其结构动力响应，随着路面摩擦系数增大，轮胎运动速度和动能降低幅度都明显增大，胎面摩擦力也相应增大，制动距离减小。凝冰沥青路面不同力学指标受路面摩擦系数影响规律不尽相同，路表弯沉和轮胎经过后的路表水平剪应力以及沿路面深度方向最大竖向应力、最大横向拉应力、最大横向拉应变和最大水平剪应力均随着摩擦系数增大而增大，路表竖向应力和轮胎经过前的路表水平剪应力则随着摩擦增大而减小。轮胎在曲线路段的运动速度和动能降低迅速，胎面摩擦力相应的增大，制动距离减小。曲线路段的路面动力响应指标普遍高于平直路段和纵坡路段，路面纵坡和超高会使路表的水平剪应力增大，却会使路面沿深度方向的相应力学指标的最大值减小。通过室内模型试验研究了凝冰沥青路面抗滑性能衰减规律并提出了预测模型，根据试验和有限元模拟结果，提出了凝冰沥青路面镶嵌破冰柱体的主动除冰抗滑装置，可有效解决凝冰沥青路面抗滑能力不足的问题，具有极大的推广应用价值。