墩台沉降对桥上纵连板式无砟轨道线路动力影响

基于耦合动力学理论,考虑纵连板式无砟轨道-桥梁系统各部件间非线性接触,建立高速列车-纵连板式无砟轨道-桥梁三维非线性有限元耦合动力学模型。运用建立的模型,研究高速列车在桥上纵连板式无砟轨道线路墩台不均匀沉降区段行驶时,墩台沉降对高速列车-纵连板式无砟轨道-桥梁耦合系统动力特性的影响。研究结果如下:①墩台不均匀沉降对高速列车、纵连板式无砟轨道各部件振动特性有很大影响,但对桥梁振动影响相对较小;②墩台不均匀沉降对最大垂向轮轨力、扣件最大压力影响较小,而对钢轨最大正弯矩、扣件最大拉力、轨道板和底座板纵向最大拉应力、CA砂浆最大压应力影响较大;③墩台不均匀沉降对耦合系统振动特性及无砟轨道动应力特性的影响不是简单的单调线性增加,而与墩台不均匀沉降引起的无砟轨道各部件间、无砟轨道与桥梁间局部脱空有关。

Effects of uneven settlement of pier and abutment on dynamic characteristics of longitudinal connected slab ballastless track on bridge

Based on the vehicle-track coupled dynamic theory, considering nonlinear contacts among components of a longitudinal connected slab ballastless track-bridge system, a 3-D nonlinear finite element coupled dynamic model for a high speed train-longitudinal connected slab ballastless track-bridge system was established. With the established model, when a high speed train passing the uneven settlement region of pier and abutment of longitudinal connected ballastless slab track on bridge, effects of uneven settlement of pier and abutment on dynamic characteristics of the high speed train-longitudinal connected slab ballastless track-bridge system were studied. The results showed that ① uneven settlement of pier and abutment greatly affects vibration characteristics of components of high speed train and longitudinal connected slab ballastless track, but it has little influence on bridge vibration;② uneven settlement of pier and abutment has relatively small influence on maximum vertical wheel-rail force and maximum pressure force on fasteners, however, it has large influence on maximum positive moment of rail, maximum tensile force of fastener, maximum longitudinal tensile stress of slab and base plate, and maximum pressure stress of CA mortar;③ effects of uneven settlement of pier and abutment on dynamic characteristics of the coupled system and dynamic stress features of ballastless track are not a simple linear monotonic increase, but related to local void among components of ballastless track and that between ballastless track and bridge caused by uneven settlement of pier and abutment.