轨道随机不平顺数值模拟及对环境振动的影响分析

Numerical Simulation of Track Stochastic Irregularity and Analysis of its Effects on Environmental Vibration

随着高速铁路的不断兴建,其运行引起的环境振动问题日益突显,如何研究高速列车运行引起的环境振动影响,是目前铁道工程领域的重要研究方向之一.对于高速列车运行引起的环境振动,其根本原因为轨道不平顺,而轨道不平顺主要为随机不平顺,因此模拟轨道随机不平顺及数值分析其影响显得尤为必要.基于既有的轨道随机不平顺数值模拟方法,给出了轨道谱关于空间频率与时间对应频率的统一转换表达式,并对频率相关轨道谱提出了分段采样的方法,这一简单处理避免了fmin及fmax两个控制频率点的遗漏.通过本文轨道随机不平顺数值模拟改进方法结果与相关研究结果对比,证明了本文改进方法是可靠的.作为改进方法的应用实例,以轨道高低不平顺为激励输入,采用二维时域动力有限元方法分析了考虑和未考虑轨道高低不平顺对路基及周围环境的振动影响,得到了与实际相似的振动水平及频谱特征随距离轨道中心线的变化规律.

With the continuous construction of high-speed railways,the problem of environmental vibration induced by passage of high-speed train has become increasingly prominent.How to study the effects of environmental vibration caused by passage of high-speed train is one of important research directions in the field of railway engineering.For the environmental vibration caused by passage of high-speed train,the primary cause is track irregularity existing.Furthermore,the majority of track irregularity is stochastic,therefore,it is especially necessary to simulate track stochastic irregularity and analyze its influences numerically.Based on the existing method which is applied to simulate track stochastic irregularity,the uniform expression which is used to relate track spectrum regarding frequency with one regarding spatial frequency is given.Meanwhile,the segmented sampling method is also proposed for track spectrum related to frequency,which can avoid omitting spectral values at two controlling points(fminand fmax)of track spectrum.Then the reliability of improved method is verified by comparing the numerical results calculated by improved method which is used to simulate track stochastic irregularity with related research results.As application examples of the improved method,track vertical profile irregularity is applied as input excitation,which is used in two-dimensional time domain dynamic finite element method,analyzing the influences of track vertical profile irregularity on subgrade and environmental vibration in two cases of considering and not considering it.According to the numerical results,the variation law that the level of vibration and spectral characteristics with the distance from the centerline of track is obtained,which is similar to realistic circumstances.