高速铁路有砟轨道路基设计荷载分析

摘要

The influence scope,the amplitude of dynamic stress on subgrade surface and the attenuation law of a-long depth were discussed based on the existing distribution model of dynamic stress.Such conclusions are made as follows:A loading and unloading cycle of the dynamic stress on subgrade surface is accomplished by a single axle load under the geometric of ballasted track.The influence distances are 3.1 m and 3.0 m respectively when the dynamic stress distribution pattern is simplified to be triangle distribution along longitudinal lines,and uni-formed distribution in lateral.Given the dynamic effect and the dynamic stress inhomogeneous distribution in transverse of subgrade surface,a computational formula of subgrade surface dynamic stress had been deduced by the mechanics equilibrium condition.The depth attenuation law of dynamic stress has been calculated according to the distribution pattern and the correction of the dynamic stress inhomogeneous distribution in transverse.The computed results are in good agreement with the field measurement.%结合现有的路基面动应力分布形式，对路基面动应力影响范围、动应力幅值以及动应力沿深度分布规律进行分析探讨，研究结果表明：高速铁路有砟轨道几何条件下，路基面动应力的一次加卸载过程由单个轴载完成。纵向三角形和横向均匀的简化分布模式下，影响距离分别为3．1 m 和3．0 m；基于力学平衡条件并考虑综合动力影响以及动应力横向不均匀分布影响，得到了路基面动应力幅值计算公式；基于确定的荷载分布模式并进行动应力横向不均匀分布影响修正计算得到动应力沿深度分布规律，与实测结果吻合较好。