路基不均匀沉降对CRTSⅡ型板式无砟轨道结构的影响分析

Analysis on the Impact of Differential Settlement of Earthworkson CRTSⅡ Slab Ballastless Track

CRTSⅡ型板式无砟轨道采用纵连结构,轨道板刚度较大,一旦路基发生不均匀沉降,将影响无砟轨道结构的受力。本文基于有限元分析理论,建立了三维有限元计算模型,分析了路基不均匀沉降和列车荷载共同作用下CRTSⅡ型板式无砟轨道结构的力学特性。研究结果表明:(1)随着不均匀沉降的出现和发展,轨道结构的应力峰值迅速增长,当沉降量大于10 mm/20 m时,轨道板已处于开裂工作状态;(2)不均匀沉降对扣件竖向受力的影响不大,对其纵向受力影响较大;(3)当沉降量为25 mm/20 m时,轨道结构出现空吊问题,并且随着沉降量的增大,轨道结构的空吊问题越来越严重,为了使轨道结构在运营期间不产生空吊问题,建议路基不均匀沉降量应小于20 mm/20 m。

CRTSⅡslab ballastless track is connected longitudinally between track slabs which are so rigid that the differential settlement of earthworks will affect the stress on the ballastless track structure.Based on the finite element analysis theory,this paper establishes a 3D finite element calculation model and analyzes the mechanical characteristics of CRTSⅡslab ballastless track structure under the combined action of differential settlement of earthworks and trainload.The results show that:(1)With the emergence and development of differential settlement,the stress peak of track structure increases rapidly,and when the settlement is more than 10 mm per 20 m,the track slab is already in a cracking working state.(2)Differential settlement has little impact on the vertical stress of fasteners,but has a great impact on their longitudinal stress.(3)When the settlement is 25mm per 20m,the problem of unsupported suspension of track structure appears,and with the increase of settlement,the problem becomes more and more serious.In order to avoid the problem of unsupported suspension of track structure during operation,it is suggested that the differential settlement of subgrade should be less than 20 mm per 20 m.