重载列车-轨道-桥梁纵向动荷载限值研究

为研究重载列车不同运行条件下的轨道-桥梁纵向动态传递规律,以多跨32m预应力混凝土简支梁桥为对象,建立考虑多车编组牵引及制动作用的重载列车-轨道-桥梁空间耦合动力学模型,对轨道-桥梁的纵向动力响应特征、桥墩纵向受力影响因素和有效制动力率进行研究。结果表明:当机车以最大能力牵引时,作用于桥墩的有效牵引力率为0.134,紧急制动时,有效制动力率为0.155,紧急制动工况比牵引工况更不利;桥墩纵向受力随跨数的增加而增大并逐渐趋于稳定,随列车轴重的增加呈线性增大;不同列车编组模式下,列车的等效制动力率不同,最大值为0.141;桥墩纵向设计荷载限值应根据列车轴重进行选取,当轴重大于33t时,应进行动力检算。

Study on Limit Value of Longitudinal Dynamic Load of Heavy Haul Railway Vehicle-Track-Bridge

In order to study the transmission law of longitudinal dynamic load on the track-bridge system under different heavy haul train operation conditions, taking a multi-span (32 m) pre-stressed concrete simply supported girder as a research object, we established a spatial coupling dynamic model of the heavy haul vehicle-track-bridge for different freight train marshalling under traction and braking. Thereby, we studied the dynamic response of the track-bridge system and the influencing factors for bridge piers and effective braking force ratio. The results indicate that when the vehicle is under full traction condition, the effective traction force ratio for piers is 0.134;when the vehicle is under emergency braking condition, the effective braking force ratio is 0.155, thus the emergency braking condition is more critical than the full traction condition. The longitudinal force on piers will continuously increase and gradually trend to be stable as the number of spans increases, and will linearly increase as the axle load of vehicle increases. Under different train marshalling, the effective braking force ratios are different, and the maximum value is 0.141. The design limit value of pier longitudinal load should be selected according to the axle load of vehicle, and the dynamic check calculation should be performed when the axle load exceeds 33 tons.