高速铁路桥上CRTSⅡ型无砟轨道快速升降温模型试验研究

为深入系统研究高速铁路桥上CRTSⅡ型纵连板式无砟轨道温度场分布规律,制作无砟轨道后张法预应力混凝土简支箱梁1/4缩尺试验模型,通过开展快速升降温试验,分析CRTSⅡ型无砟轨道二维温度场分布规律,提出轨道系统横、竖向温度三维分布形式。研究结果表明:高速铁路桥上CRTSⅡ型无砟轨道竖向温度及温差分布呈三段式阶梯形;横向温度分布呈抛物线形;CA砂浆层是影响轨道系统横、竖向温度场分布的最主要因素;轨道系统竖向负温差主要产生于轨道板;轨道板与CA砂浆层间竖向温度梯度最为显著,最高达4.5℃/cm;横向最大负温差为-4.4℃,最大正温差为5.5℃,分别产生于底座板上部和中部;轨道系统横、竖向温度三维分布呈三段式阶梯形曲面。研究结果可为高速铁路桥上CRTSⅡ型无砟轨道温度效应设计和研究提供参考。

Model Test Study on CRTSⅡBallastless Track under Rapid Temperature Rise and Fall on High-speed Railway Bridge

In order to study the temperature field distribution of CRTSⅡlongitudinal connecting slab ballastless track on high-speed railway bridge,a 1/4 scale test model of post-tensioned prestressed concrete simply supported box girder and ballastless track was established.Through the test of rapid rise and fall of the extreme high temperature,the two-dimensional temperature field distribution law of CRTSⅡballastless track was studied,and the three-dimensional distribution pattern of transverse and vertical temperature of track system was put forward.The results show that the vertical temperature and temperature difference distribution of CRTSⅡballastless track on high speed railway bridge show a three-stage ladder shape,and the transverse temperature distribution is parabolic.The CA mortar layer is the most significant factor affecting the transverse and vertical temperature field distribution of the track system.The negative vertical temperature difference of the track system is mainly produced by the track slab.The vertical temperature gradient between the track slab and the CA mortar layer is as high as 4.5℃/cm,which is the most significant.The maximum transverse negative temperature difference of the track system is-4.4℃,and the maximum positive temperature difference is 5.5℃,which is produced in the upper and middle parts of the bottom base respectively.The three-dimensional distribution of the transverse and vertical temperature of the track system is a three-stage stepped surface.The research results can provide reference for the design and research of temperature effect of CRTSⅡballastless track on high-speed railway bridges.