高温季节桥上CRTSⅡ型板式无砟轨道温度分布试验研究

Experimental study on temperature distribution of CRTSⅡballastless track on high-speed railway bridge in summer

为研究高温季节高速铁路桥上CRTSⅡ型板式无砟轨道的温度分布规律,制作CRTSⅡ型板式无砟轨道-预应力混凝土简支箱梁1:4缩尺试验模型。通过开展夏季典型高温天气的温度试验,分析高速铁路桥上CRTSⅡ型板式无砟轨道结构的温度分布变化规律,研究无砟轨道横、竖向温度分布型式。结果表明:在非阳光直射条件下,高速铁路桥上CRTSⅡ型板式无砟轨道竖向温度分布、温差分布和温度梯度分布均呈"S"形非线性分布,且呈周期性变化;轨道板与CA砂浆层间竖向温度梯度为正温度梯度,最不利竖向负温度梯度发生于CA砂浆层与底座板层间;CA砂浆内部竖向温度梯度最显著,最大值为27.0℃/m;无砟轨道横向温度分布呈抛物线型,三维温度分布呈马鞍形曲面。

To study the temperature distribution of CRTSⅡballastless track on high-speed railway(HRB)bridge in summer,a 1:4 scale test model of ballastless track with prestressed concrete simply supported box girder structure was constructed.Through the temperature test under typical high temperature weather in laboratory,the uniform temperature distribution of CRTSII ballastless track structure on high speed railway bridge was analysed,and the distribution of transverse and vertical temperature about the ballastless track was studied.The results show that:Under non-direct sunlight conditions,the temperature difference distribution and temperature gradient distribution of CRTS II ballasted track on high speed railway bridge are all“S”type and change periodically.The vertical temperature gradient between track slab and CA mortar is positive temperature gradient,and the most unfavorable vertical negative temperature gradient occurs between CA mortar and bottom base.The vertical temperature gradient of CA mortar is the most significant part in the track with a maximum value of 27.0℃/m.The transverse temperature distribution of CRTSⅡballastless track on HRB bridge is parabolic and the threedimensional temperature distribution is saddle-shaped surface.