中文摘要：

采用Hertz弹性接触模型，推导考虑轨道不平顺的移动车轮-轨道-桥梁耦合单元动力方程，结合车辆动力方程建立车-线-桥耦合系统运动方程，采用自动半步长方法以精确确定轮轨接触状态发生改变的时刻，使用Newmark-β方法直接积分求解。将预应力混凝土简支箱梁桥徐变变形引入轨道不平顺（徐变不平顺），研究其对车-线-桥耦合系统动力响应的影响。结果表明，轨道对徐变变形产生的折角具有明显的缓和作用，能显著降低轮轨接触力和轨道加速度响应；徐变不平顺会引起明显的梁端冲击，显著增加系统的动力响应；采取延长半年铺轨的措施能达到较好的动力控制效果，且对车体加速度的控制效果最明显，响应降低约42％；多跨简支梁桥的周期性徐变不平顺能激起车体更强烈的固有频率振动，同时也表现出波长为梁长一半的受迫振动；不考虑徐变不平顺时相应的敏感波长等于梁长。

英文摘要：

With Hertz elastic contact model, a moving wheel-track-bridge interaction element dynamic equation considering track irregularity was derived. According to vehicle dynamic equations, the motion equations of train-track-bridge interaction system were established. The auto-half-step algorithm was adopted to determine accurately the occurrence time when the wheel-rail contact status changing and the New- mark-β method was used to directly find integral solutions. The creep deformation of simply supported prestressed concrete box bridge was taken as track irregularity （creep irregularity） and its influence on the dynamic response of train-track-bridge interaction system was researched. The results demonstrate that the track has an obvious smoothing effect on the angle caused by creep deformation, and wheel-rail contact force and track acceleration response can be significantly reduced. The creep irregularity can cause strong impact of beam end and can obviously increase the dynamic response of the system. By extending track laying time for about half a year, better dynamic control effect can be achieved. The control effect on vehicle acceleration is the most significant and the response is decreased about 42%. The periodic creep irregulari- ty of multi-span simply supported bridge can cause stronger natural frequency vibration of carbody and meanwhile can cause forced vibration with the wavelength half of the beam length. The corresponding sensitive wavelength of vibration equals to beam length regardless of creep irregularity.