中文摘要：

研究目的：针对大轴重重载铁路扣件刚度的合理取值问题,基于车辆-轨道耦合动力学理论,以美国五级轨道谱作为激励输入,分析扣件刚度对低频振动响应的影响;利用三维轮轨瞬态滚动接触显式有限元模型,分析钢轨波磨、焊接接头和车轮擦伤等短波长几何不平顺激励下扣件刚度对轨道高频动态响应的影响规律。研究结论：（1）大轴重重载铁路扣件刚度主要取决于钢轨位移和轨枕承载能力,钢轨位移决定了扣件刚度的下限,轨枕承载能力决定了扣件刚度的上限;（2）扣件刚度对于低频动态响应（小于50 Hz）的影响可以忽略;随着扣件刚度的增加,短波不平顺所激起的最大轮轨力呈现出逐渐变小的趋势,最大枕上压力和道床应力却逐渐变大,轮轨力和道床应力在扣件刚度大于200 MN/m以后减小幅度变缓,趋于稳定,相对于轮轨力和道床应力,枕上压力对扣件刚度的变化更为敏感;（3）综合考虑轮轨力、钢轨位移和轨枕承载能力,对于设计轴重40 t、最高行车速度90 km/h的重载有砟轨道结构,若钢轨的最大容许垂向位移为3.30 mm,最大容许枕上压力为150 kN,则最优扣件动态刚度范围为200-250 MN/m;若最大容许枕上压力为180 kN,则最优扣件动态刚度范围为200-600 MN/m;（4）本研究结果可供大轴重重载铁路轨道结构设计参考。

英文摘要：

Research purposes： In order to find the reasonable value of fastener stiffness on the heavy haul railway running 40 t axle - load trains, based on the theory of vehicle - track coupling dynamics, the effect of fastener stiffness on the low frequency vibration was studied by using AAR.5 track irregularity spectrum as an excitation. A transient three dimensional wheel / rail rolling contact explicit finite element model was developed to analyze the effect of fastener stiffness on the high frequency vibration by taking the short wavelength irregularity excitation such as rail corrugation, welding joint and the wheel abrasion into consideration. Research conclusions： （ 1 ） The fastener stiffness on the heavy haul lines mainly depends on the rail ＂s vertical displacement and the sleeper＇s load - bearing capacity. The lower limit of the fastener stiffness is determined by rail displacement, and the upper limit is determined by sleeper bearing capacity. （2） The effect of fastener stiffness on low frequency response （below 50 Hz） can be ignored. With the increase of fastener stiffness, the maximum wheel - rail contact force induced by the short wavelength irregularities gradually decreases, and the maximum pressure on rail ditch and ballast stress gradually become larger. The decreasing trend of wheel -rail contact force and ballast stress is slowing down and gradually tends to be stable after the fastener stiffness exceeds 200 MN/m. Relative to the wheel - rail contact force and ballast stress, the pressure on rail ditch is more sensitive to the change of fastener stiffness. （3） Taking the wheel -rail force, rail displacement and sleeper bearing capacity as criteria, as far as a heavy haul ballasted track structure which is characterized by 40 t axle - load and 90 km/h speed is concerned, the optimal dynamic fastener stiffness ranges from 200 MN/m to 250 MN/m in case the maximum allowable rail displacement is 3.30 mm and rail ditch pressure is 150 kN, and the optimal dynamic stiffness ranges from