地震作用下铁路斜拉桥动力响应及行车安全性研究

DYNAMIC RESPONSES AND TRAIN RUNNING SAFETY OF RAILWAY CABLE-STAYED BRIDGE UNDER EARTHQUAKES

为研究高速铁路斜拉桥在地震作用下的车-桥耦合动力响应及列车走行性能,以新建杭长客专铁路长沙段(112 m+80 m+32 m)槽型截面独塔斜拉桥为研究对象,利用车-线-桥耦合动力学分析软件TRBF-DYNA建立了考虑地震作用的列车-轨道-桥梁耦合系统空间动力分析模型。采用等效荷载法计算轨道-桥梁子系统的地震响应,通过考虑拟静力位移分量,将钢轨相对地震响应转化为绝对坐标系下动力响应,最终通过空间轮轨滚动接触模型将地震作用传递至车辆子系统。对比分析了不同列车运行速度和不同地震强度条件下桥梁、列车动力响应的变化规律,评估了列车行车安全性能。结果表明:地震对列车运行安全性有显著影响,根据我国规范可判断列车在7度、8度、9度多遇地震下的安全行车速度阈值分别为200 km/h、180 km/h和140 km/h;根据轮轨接触评判准则,在80 km/h^240 km/h的行车速度范围内,在7度、8度和9度多遇地震下轮轨相对位移仍在安全范围内。

To investigate the train-bridge coupling dynamic responses and train running performances of high-speed railway cable-stayed bridge system under earthquake, a single tower cable-stayed bridge（112 m＋80 m＋32 m） with channel section, which is located in Changsha part of Hangzhou-Changsha dedicated passenger line, was taken for a case study. A spatial dynamic analysis model of train-track-bridge coupled system subjected to earthquakes was established by computational analysis software TRBF-DYNA. The seismic responses of track-bridge subsystem were calculated by the equivalent load method. The relative seismic responses of rail were transformed to the dynamic response in the absolute coordinate system through considering pseudo-static displacement component. Finally the seismic action was applied to the train through the spatial wheel-rail rolling contact model. The variations of bridge-train dynamic responses and train running safety were analyzed under different running speeds and seismic intensities. The results show that seismic excitations have significant influence on the train running safety, and the safety velocity thresholds of train corresponding to the frequent earthquake intensities of 7, 8 and 9 are respectively 200 km/h, 180km/h and 140 km/h according to Chinese national code. Meanwhile, according to the wheel-rail contact judgment criteria, the wheel-rail relative displacements are still within safety range under frequent earthquakes with intensity of 7, 8 and 9 when the range of train speed is from 80 km/h to 240 km/h.