道床裂纹对无砟轨道振动的影响初探

Preliminary Study on the Effect of Ballastless Bed Cracks on Track Vibration

为研究无砟轨道道床开裂后结构受力,将混凝土道床简化为黏弹性连续支承梁,引入损伤函数表达道床裂纹,基于轮轨系统动力学理论,建立考虑道床裂纹的车辆-双块式轨道垂向耦合动力学模型,计算分析了高速车辆通过具有半波余弦不平顺轨道时的振动响应,并分析了车辆速度对轨道有无裂纹时振动的影响。结果表明,道床裂纹对车辆和钢轨的振动影响很小,而对道床本身及其下部结构的振动影响较为显著,道床动弯应力和路基面动应力随着车辆速度的增大而明显增大。

In order to investigate the mechanics of cracked ballastless beds,taking the ballastless bed as the viscoelastic continuously supported beam and expressing its cracks by a damage function,the vertical dynamic coupling model of the vehicle and double-block ballastless track with bed cracks was established on the basis of the theory of wheel-rail system dynamics,and the vibration responses of the ballastless track with semi-cosine irregularities were calculated when high-speed vehicles passed through.The effect of vehicle velocities to track dynamic responses was analyzed for ballastless beds with and without cracks.The results show that bed cracks have little influence on vehicle and rail vibration responses,and have obvious influence on vibration of the ballastless bed itself and its substructure,the dynamic bending stress of the ballastless bed and the dynamic stress of the subgrade increase obviously with the increase of the vehicle velocity.