城市轨道交通板式无砟轨道结构摊铺层粗糙表面的构建及评价指标研究

Construction and evaluation index of rough surface of pavement of ballastless track structure in urban rail transit

为研究摊铺层粗糙度对城市轨道交通板式无砟轨道结构力学性能的影响及其合理设计值,首先,基于W-M分形函数,利用Python编程构建具有高度随机性的摊铺层分形粗糙表面,并将得到的分形粗糙表面导入Geomagic DX软件,通过面片修补等操作生成三维粗糙表面实体模型;然后,将三维粗糙表面实体模型作为部件导入ABAQUS有限元软件,并在此基础上构建具有粗糙摊铺层的城市轨道交通板式无砟轨道有限元模型;最后,在城市轨道交通板式无砟轨道有限元模型上施加符合实际情况的荷载以及边界条件,进行准静态有限元仿真计算,得到钢轨、轨道板和基底等轨道结构部件的位移以及应力响应,并将得到的力学响应与相关文献进行对比验证。研究结果表明:不设置弹性垫层的轨道结构难以满足服役要求;当特征常数G不变时,随着分形维数D增加,轨道结构各部分的响应均增大,两者呈明显正相关关系;当G=0.004 m,D=2.1时,轨道板位移超过相关限值。综合安全性以及现场操作简易性考虑,粗糙度测量曲线幅值不应大于3 mm。

To study the influence of paving layer roughness on the mechanical properties of slab ballastless track structure of urban rail transit and its reasonable design value,firstly,on the basis of W-M fractal function,the fractal rough surface with high randomness was constructed by Python programming,the fractal rough surface was imported into the Geomagic DX software,and the 3D rough surface solid model was generated by patching and other operations.Then,the three-dimensional rough surface solid model was imported into ABAQUS finite element software as component.On this basis,the finite element model of urban rail transit slab ballastless track with rough paving layer was constructed.Finally,the quasi-static finite element simulation calculation was carried out on the finite element model of slab ballastless track of urban rail transit with the load and boundary conditions in line with the actual situation.The displacement and stress response of the rail,track slab and base and other track structural components were obtained,and the mechanical response obtained was compared with the relevant literature for verification.The results show that the track structure without elastic cushion is difficult to meet the service requirements.When the characteristic constant G is constant,the response of all parts of the track structure increases with the increase of fractal dimension D,showing a significant positive correlation.When G is 0.004 m and D is 2.1,the displacement of the track plate exceeds the relevant limit.Considering the safety and simplicity of operation on site,the amplitude of roughness measurement curve should not be greater than 3 mm.