摘要
建立三维有限元CRTSⅢ型板式无砟轨道-路基-天然地基土非线性数值分析模型,基于轨道随机不平顺条件下计算得到轮轨载荷,通过有限元软件二次开发子程序将轮轨载荷导入有限元模型,路基两端及天然地基土体四周采用等效三维一致粘弹性人工边界模拟工程实际半无限空间体,在此基础上研究分析高速移动荷载作用下路基的动位移分布规律。研究结果表明:文章采用的有限元模型计算得到的路基竖向动位移远小于我国现行高速铁路标准的控制值3.5 mm,满足要求;列车模型为两节动车,中间两组轮对移动产生的动位移叠加,竖向动位移在各结构层中的时程曲线峰值与转向架数目进行对应;沿横向分布,在混凝土底座范围内,路基各结构层竖向动位移幅值沿横向分布变化较小,各结构层横向最大差值仅为0.129 mm;在混凝土底座范围外,路基各结构层竖向动位移幅值横向分布差异较大,横向最大差值均超过0.5 mm;随着深度的增加,竖向动位移在路基中随着深度的增加逐渐衰减,最大值位于基床表层顶面,近似线性衰减;基床表层刚度的变化对系统动力响应影响作用较有限,基床底层刚度的增大对降低路基中的动位移影响作用较显著,有利于行车运行的平稳、舒适及安全,提高列车时速会加大路基的变形位移,地基土刚度的变化对路基中对降低系统动位移的作用最显著。
A nonlinear numerical analysis model for three-dimensional finite element of CRTSⅢslab ballast less track-subgrade-natural foundation soil is established,and the wheel/rail load is calculated based on the random irregularity of the track.The wheel/rail load is imported into the finite element model by secondary development subroutine of finite element software,and the equivalent three-dimensional uniform viscoelastic artificial boundary is used to simulate the actual semi-infinite space at both ends of the subgrade around the natural foundation soil.Accordingly,the dynamic displacement distribution of subgrade under high speed moving load is studied and analyzed.The results show that the vertical dynamic displacement of the subgrade calculated by the finite element model is far less than the current standard control value of China’s high-speed railway of 3.5 mm which meets the requirements.The train model adopts two bullet cars,and the dynamic displacement generated by the movement of two sets of wheel sets in the middle is superimposed.The peak value of the vertical dynamic displacement in the time history curve of each structure layer corresponds to the number of bogies.In the range of concrete base,the vertical dynamic displacement amplitude of each structural layer of subgrade changes little along the transverse distribution,and the maximum transverse difference of each structural layer is only 0.129 mm.Outside the range of concrete base,the vertical dynamic displacement amplitude of each structural layer of subgrade has a great difference in transverse distribution,and the maximum transverse difference is more than 0.5 mm.With the increase of depth,the vertical dynamic displacement in the subgrade gradually attenuates,and the maximum value is located at the top surface of the foundation bed,which attenuates approximately linearly.The impact of roadbed surface stiffness changes on the system dynamic response is limited.The increase of the roadbed foundation stiffness has a significant effect on reducing t
作者
冯靖淳
罗文俊
徐鑫洋
杜可
Feng Jingchun;Luo Wenjun;Xu Xinyang;Du Ke(School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China)
出处
《华东交通大学学报》
2021年第4期45-53,126,共10页
Journal of East China Jiaotong University
基金
国家自然科学基金(51978265)
江西省主要学科学术和技术带头人培养计划(20194BCJ22009)。
关键词
随机不平顺
无砟轨道
动位移
高速铁路
random irregularity
ballastless track
dynamic displacement
high-speed railway
