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(...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。展开更多
Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under earthquakes.Taking a high-speed railway simply-sup...Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under earthquakes.Taking a high-speed railway simply-supported girder bridge with eight spans crossing an active strike-slip fault as the research object,a refined coupling dynamic model of the high-speed train-CRTS III slab ballastless track-bridge system was established based on ABAQUS.The rationality of the established model was thoroughly discussed.The horizontal ground motions in a fault rupture zone were simulated and transient dynamic analyses of the high-speed train-track-bridge coupling system under 3-dimensional seismic excitations were subsequently performed.The safe running speed limits of a high-speed train under different earthquake levels(frequent occurrence,design and rare occurrence)were assessed based on wheel-rail dynamic(lateral wheel-rail force,derailment coefficient and wheel-load reduction rate)and rail deformation(rail dislocation,parallel turning angle and turning angle)indicators.Parameter optimization was then investigated in terms of the rail fastener stiffness and isolation layer friction coefficient.Results of the wheel-rail dynamic indicators demonstrate the safe running speed limits for the high-speed train to be approximately 200 km/h and 80 km/h under frequent and design earthquakes,while the train is unable to run safely under rare earthquakes.In addition,the rail deformations under frequent,design and rare earthquakes meet the safe running requirements of the high-speed train for the speeds of 250,100 and 50 km/h,respectively.The speed limits determined for the wheel-rail dynamic indicators are lower due to the complex coupling effect of the train-track-bridge system under track irregularity.The running safety of the train was improved by increasing the fastener stiffness and isolation layer friction coefficient.At the rail fastener lateral stiffness of 60 kN/mm and isolation layer friction coefficients of 0.9 and 0.8,respectively,the safe running speed limits of the high-speed train increased to 250 km/h and 100 km/h under frequent and design earthquakes,respectively.展开更多
文摘弯道交通事故高发,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。
基金Project(51378050) supported by the National Natural Science Foundation of ChinaProject(B13002) supported by the “111” Project,China+2 种基金Project (8192035) supported by the Beijing Municipal Natural Science Foundation,ChinaProject(P2019G002) supported by the Science and Technology Research and Development Program of China RailwayProject(2019YJ193) supported by the State Key Laboratory for Track Technology of High-speed Railway,China。
文摘Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under earthquakes.Taking a high-speed railway simply-supported girder bridge with eight spans crossing an active strike-slip fault as the research object,a refined coupling dynamic model of the high-speed train-CRTS III slab ballastless track-bridge system was established based on ABAQUS.The rationality of the established model was thoroughly discussed.The horizontal ground motions in a fault rupture zone were simulated and transient dynamic analyses of the high-speed train-track-bridge coupling system under 3-dimensional seismic excitations were subsequently performed.The safe running speed limits of a high-speed train under different earthquake levels(frequent occurrence,design and rare occurrence)were assessed based on wheel-rail dynamic(lateral wheel-rail force,derailment coefficient and wheel-load reduction rate)and rail deformation(rail dislocation,parallel turning angle and turning angle)indicators.Parameter optimization was then investigated in terms of the rail fastener stiffness and isolation layer friction coefficient.Results of the wheel-rail dynamic indicators demonstrate the safe running speed limits for the high-speed train to be approximately 200 km/h and 80 km/h under frequent and design earthquakes,while the train is unable to run safely under rare earthquakes.In addition,the rail deformations under frequent,design and rare earthquakes meet the safe running requirements of the high-speed train for the speeds of 250,100 and 50 km/h,respectively.The speed limits determined for the wheel-rail dynamic indicators are lower due to the complex coupling effect of the train-track-bridge system under track irregularity.The running safety of the train was improved by increasing the fastener stiffness and isolation layer friction coefficient.At the rail fastener lateral stiffness of 60 kN/mm and isolation layer friction coefficients of 0.9 and 0.8,respectively,the safe running speed limits of the high-speed train increased to 250 km/h and 100 km/h under frequent and design earthquakes,respectively.
