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...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.展开更多
为解决铁路跨越复杂艰险山区河谷难题,为复杂艰险山区铁路修建选线提供更加灵活的操作空间,为跨越复杂艰险山区铁路提供强有力的技术支撑,设计研究了跨度(81+135+432+135+81)m半漂浮结构体系钢桁梁斜拉桥。桥梁最高墩高为139 m A型墩、...为解决铁路跨越复杂艰险山区河谷难题,为复杂艰险山区铁路修建选线提供更加灵活的操作空间,为跨越复杂艰险山区铁路提供强有力的技术支撑,设计研究了跨度(81+135+432+135+81)m半漂浮结构体系钢桁梁斜拉桥。桥梁最高墩高为139 m A型墩、跨度为(80+3×144+80)m的超高墩大跨铁路连续刚构桥;桥梁最高墩高为116 m人字墩、联长777.7 m、跨度为(52+7×96+52)m的超高墩大跨铁路连续刚构桥梁结构。确定了大桥的横向自振周期值,进行了车桥耦合动力分析,满足了时速200 km客货共线铁路车辆的安全性及舒适性,桥梁的安全性。提出了适应艰险山区,横向刚度大、稳定性好、适应地形能力强、圬工量节省、经济性好、造型美观的A型(含人字)超高墩结构。展开更多
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)+1 种基金the Research Project of State Key Laboratory of Traction Power(Grant No.2014TPL_T01)the 2015 Doctors’Innovation Fund of Southwest Jiaotong University
文摘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.
