弯道交通事故高发,车辆超速行驶、潮湿路面抗滑性能不足及离心力作用所造成的车辆侧向滑移是其主要事故类型.明确潮湿弯道车辆最大安全行驶速度对于保证弯道安全驾驶至关重要,由于轮胎-水流-路面之间的相互作用机理复杂,涉及变量较多(包括弯道几何参数、路面表面特征、轮胎运动特性、水膜厚度等),目前还没有从抗滑模拟角度获取降雨工况下弯道最大安全行驶速度的工程实践.基于固体力学和流体力学,建立轮胎-水流-路面耦合的侧偏抗滑模型,并依据抗滑测试值对模型预测准确性进行验证.以侧偏抗滑模型为基础,结合侧滑机理分析,得到所验证沥青路面在不同弯道半径、超高和水膜厚度下的最大安全行驶速度,并与美国国家公路与运输协会(American Association of State Highway and Transportation,AASHTO)设计速度进行对比.结果表明:现有设计速度规范对雨天环境因素考虑不足,当降雨强度较大时,车辆以AASHTO设计速度行驶会发生侧向滑移.该结果验证了所建立侧偏抗滑模型求解最大安全车速的方法对识别具有高滑移风险的雨天环境状况和低抗滑性能路面的有效性,并可为弯道路面摩擦管理和混合料设计提供新手段.
Simulation of Pavement Skid Resistance on Wet Horizontal Curves and Calculation of Safe Driving Speed
Horizontal curves are accident-prone sections in a road network.The main type of curve-related crashes is vehicle sideway skidding,due to vehicle overspeeding,the insufficient skid resistance of wet pavement and effect of centrifugal force when a vehicle negotiating a horizontal curve.It is vital to determine the maximum safe driving speed of vehicles to ensure safe driving on wet horizontal curves.Owing to the complex interaction mechanism between tire-water-pavement and many variables involved(including curve geometric parameters,pavement surface characteristics,tire motion characteristics,water film thickness,etc.),currently there is no practical working procedure to determine the maximum safe driving speed of a vehicle on a horizontal curve under wet weather condition by skid resistance simulation.Based on solid mechanics and fluid mechanics,a coupled tire-fluid-pavement cornering skid resistance simulation model was established,and the prediction accuracy of the model was verified according to skid resistance test values.By the skid resistance simulation model and the mechanism analysis of sideway skidding,the maximum safe driving speeds of the verified asphalt pavement under different curve radii,superelevation rates and water film thicknesses were obtained,and these calculated safe driving speeds were compared with American Association of State Highway and Transportation(AASHTO)design speeds.The results show that the existing design speed specification does not fully consider the rainy environmental factors,and the vehicle will slip sideways at the AASHTO design speed under heavy rainfall intensity.The results validates the effectiveness of the approach of calculating the maximum safe speed by skid resistance simulation model in identifying the rainy conditions and low skid resistance pavement surface with high skidding risk.And the approach can also provide a new method for pavement skid resistance management and mixture design.
pavement skid resistancesafe driving speedhorizontal curvefinite element modelsideway skidding
万方数据
维普
