高速铁路无砟轨道不平顺分形特征分析

Analysis on fractal characteristics of the ballastless track irregularities of high-speed railways

无砟轨道不平顺作为线路服役状态的直接表征,一直是高速铁路检查与维修作业的核心。为了深刻而有效地掌握无砟轨道不平顺的时空分布特征,从分形几何的基础物理含义出发,确定轨道不平顺的分形特征,比选轨道不平顺分形维数的计算方法,通过分析典型高速铁路无砟轨道不平顺的累计检测数据,讨论分形维数进行轨道区段质量管理的可行性与合理性。结果表明:轨道不平顺具有典型自相似性和标度不变性的分形特征,各种分形维数方法进行轨道不平顺计算的结果具有显著差异性,变差法计算的精度、鲁棒性好,适合进行轨道不平顺分形维数计算;分形维数可以有效地表征线路轨道服役状态逐渐恶化的趋势,受线路作业维修干扰较少。建议结合线路具体养修条件,进一步对不同线路条件下轨道不平顺分形维数特征进行深入研究。

Ballastless track irregularities,as a direct indicator of the line’s service status,have always been the core of high-speed railway inspection and maintenance operations.In order to deeply and effectively grasp the temporal and spatial distribution characteristics of ballastless track irregularities,starting from the basic physical meaning of fractal geometry,the fractal characteristics of track irregularities were analysed and the calculation methods for the fractal dimension of track irregularities were compared and selected.By analyzing the typical high-speed railways accumulated inspection data of ballastless track irregularities,the feasibility and rationality of the quality management of track sections by using the fractal dimension were discussed.The results show that track irregularities have typical fractal characteristics of self-similarity and scale invariance;the results of track irregularity calculations by various fractal dimension methods have significant differences,and with a view to the calculation accuracy and robustness,the variation method is more suitable for calculating the fractal dimension of track irregularity.The fractal dimension can effectively characterize the trend of deteriorating service status of the track,and it is less disturbed by the line operation and maintenance.It is suggested to further study the characteristics of the fractal dimension of track irregularities under different track conditions based on the specific maintenance conditions of the track.