摘要
This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways.An analytical expression of the mapping relationship between the pier settlement and the rail deformation is derived theoretically for the double block ballastless track-bridge system.By adopting the superposition of the track random irregularity and the rail deformation caused by the pier settlement as the excitation inputs,the variations of vehicle dynamics indices with pier settlement are comparatively analyzed.Then,the safety threshold of the bridge pier settlement is obtained according to the limit of vehicle running safety and ride comfort indices of the high-speed trains.Results show that the dynamics indices of different trains have different sensitivities to the pier settlement,and the train CRH2C is the most sensitive one among all the types of Chinese high-speed trains.When passing through the bridges in common span with pier settlement at the speed of 250–350 km/h,the trains suffer the low-frequency excitations,and the vertical acceleration of car body is most sensitive to the pier settlement of all the dynamics indices.When the car body vertical acceleration just exceeds the allowable limit,the critical settlement value is 23.4 mm,which is much bigger than the pier differential settlement limit in the current code for Chinese high-speed railways.
This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways. An analytical expression of the mapping relationship between the pier settlement and the rail deformation is derived theoretically for the double block ballastless track-bridge system. By adopting the superposition of the track random irregularity and the rail de- formation caused by the pier settlement as the excitation inputs, the variations of vehicle dynamics indices with pier settlement are comparatively analyzed. Then, the safety threshold of the bridge pier settlement is obtained according to the limit of vehi- cle running safety and ride comfort indices of the high-speed trains. Results show that the dynamics indices of different trains have different sensitivities to the pier settlement, and the train CRH2C is the most sensitive one among all the types of Chinese high-speed trains. When passing through the bridges in common span with pier settlement at the speed of 250-350 km/h, the trains suffer the low-frequency excitations, and the vertical acceleration of car body is most sensitive to the pier settlement of all the dynamics indices. When the car body vertical acceleration just exceeds the allowable limit, the critical settlement value is 23.4 mm, which is much bigger than the pier differential settlement limit in the current code for Chinese high-speed rail- ways
基金
supported by the National Basic Research Program of China("973"Program)(Grant Nos.2013CB036206 and 2013CB036205)
the National Natural Science Foundation of China(Grant No.50838006)
the Research Project of State Key Laboratory of Traction Power(Grant No.2014TPL_T01)
the 2015 Doctors’Innovation Fund of Southwest Jiaotong University
关键词
桥墩沉降
高速列车
安全阈值
高速铁路
动力相互作用
轨道
桥梁
垂直加速度
high-speed railway, pier settlement, safety threshold, dynamic characteristics, train-track-bridge dynamic interaction