列车荷载下考虑道床裂纹的无砟轨道受力特性  

Mechanical Analysis of Ballastless Track with Damaged Cracks under Train Load

作　　者：林红松[1] 李培刚[2] 颜华[1] 刘学毅[2] 

机构地区：[1]中铁二院工程集团有限责任公司土木建筑设计研究二院,四川成都610031 [2]西南交通大学土木工程学院,四川成都610031

出　　处：《西南交通大学学报》2010年第6期904-908,共5页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金主任基金资助项目(50848015)

摘　　要：为研究道床裂纹对无砟轨道受力的影响,根据道床裂纹的特点,基于线弹性断裂力学理论,构造20节点六面体奇异等参单元反映裂纹尖端奇异,建立含裂纹的无砟轨道空间有限元模型,分析无砟轨道的受力特性.结果表明:道床裂纹对钢轨和道床板垂向位移影响较小,对道床板中上部混凝土及钢筋受力的影响不明显,道床下层钢筋应力在裂纹处发生突变,静态和动态裂纹宽度基本相同;对于道床底面60 mm等深裂纹,在列车荷载作用下,裂纹处钢筋应力增大为未开裂时的2倍左右,裂纹张开0.017 mm.In order to study the effect of cracks on the mechanics of ballastless track,a spatial finite element model of ballastless track with a crack was established based on the cracking characteristics of in-situ concrete layer,in which the singularity of the crack tip was simulated by 20-node hexahedron isoparametric singular element using the theory of elastic fracture mechanics.The mechanics of ballastless track under train load was then analyzed.The results show that the effect of the roadbed slab crack on the vertical displacements of rail and roadbed slab is small,and on the stresses of the top bar and concrete of the roadbed slab is not remarkable.Besides,the stress of the bottom bar has a sudden increase at the crack tip;the static and dynamic crack widths are almost the same.Under train load,for the roadbed slab with a 60 mm deep bottom crack,the crack width increases to 0.017 mm,and the bar stress at the crack tip is two times that without cracks.

关 键 词：无砟轨道 裂纹 列车荷载 

分 类 号：U213[交通运输工程—道路与铁道工程]