普通短轨枕轨道结构钢轨波磨初步研究

Preliminary Study on the Rail Corrugation of the Fixed-dual Short Sleepers Track

研究某地铁普通短轨枕轨道结构小半径曲线上125～160 mm波长波磨形成机理。通过现场调查和试验测试,并结合轨道结构动力学理论对波磨形成机理进行预测分析;建立该轨道结构的三维有限元模型,利用该模型分析轨道结构的模态振型以及频响特性,并总结出该轨道结构的动态特性与钢轨波磨的关系。其中,频响分析时探讨簧下质量对轨道结构响应以及波磨成因的影响。数值计算结果与现场测试结果相吻合。研究发现该轨道结构60～80 Hz的振动是125～160 mm波长波磨形成的根本原因。由于该结构的轨枕直接嵌入轨道板中形成整体,轨道结构隔振性能差,车辆通过该轨道结构时极易发生钢轨和道床板一起相对地基的垂向弯曲振动,从而导致了125～160 mm波长波磨的形成。

The mechanism of rail corrugation, of which the wavelength is 125-160 mm, on tight curved track in metro line is investigated. Filed observations and measurements are conducted and the possible reason of the corrugation is analyzed according to the theory of track structure dynamics. Then a three-dimensional numerical model of the track structure is established by using finite element program ABAQUS and it was used to analyze the model shape and frequency response characteristic of the track structure. At last it is adopted to explore the relationship between rail corrugation and dynamic characteristics of the track. The effect of unsprung mass on the track response and the cause of corrugation are studied. The simulated results are in pretty good agreement with the measurement results. Numerical results show that the resonant frequency in the band of 60-80 Hz of the track structure, in which the rail and slab vibrates with the subgrade in vertical direction, is the underlying cause of the 120-160 mm wavelength corrugation. The anti-vibration performance is poor since the sleeper of the track is directly embedded in the slab. The corrugation results from the vertical bending vibration of the track structure when the vehicle passes over.