轨道交通U形梁日照温度梯度效应分析  

Sunlight temperature gradient effect of rail transit U-shaped beam

作　　者：董旭[1] 李树忱[1] 王鹏程[1] 郭剑 张峰[1] 

机构地区：[1]山东大学岩土与结构工程研究中心,山东济南250061 [2]中铁十四局集团第五工程有限公司,山东兖州272117

出　　处：《哈尔滨工程大学学报》2017年第7期1121-1128,共8页Journal of Harbin Engineering University

基　　金：国家自然科学基金项目(51179098;51379113)

摘　　要：针对轨道交通U形梁日照温度梯度模式及温度自应力的分布规律,本文以青岛地区某无砟轨道交通U形梁为研究对象,对其跨中U形断面进行了48 h日照温度场及温度自应力现场连续观测,得到了最大温差时刻竖向及横向温度场分布,建立了U形梁日照温度梯度模式。利用有限元数值模型,计算了不同温度梯度模式产生的温差效应,并与实测结果进行对比。研究结果表明:U形梁应分别考虑腹板及底板的竖向温度梯度模式,腹板竖向温度梯度为指数函数和线性函数组成的分段函数,底板竖向温度梯度为指数函数;朝阳侧腹板中部横向温度梯度较为明显,其他部位较小;由于温差效应影响,底板下缘及朝阳侧腹板内侧产生了较大的纵向拉应力,在设计中应给予考虑。To study the temperature gradient pattern and thermal self-restraint stress distribution regularities of urban rail transit U-shaped beam, with the U-shaped beam in a ballastless track line of Qingdao Region as the research object, field observations of solar temperature field and thermal self-restraint stress were carried out within 48 h in the midspan of U-shaped beam. The vertical and transverse temperature field distributions at the maximum tempera-ture difference moment were established, and the temperature gradient pattern of U-shaped beam was proposed. 11- sing the finite-element numerical model, the thermal difference effect caused by different temperature gradient modes was calculated and compared with actual results. The findings show that the vertical temperature gradient pattern of the web and the bottom plate should be considered separately. The vertical temperature gradient of the web is a piecewise function composed of exponential function and linear function ; the vertical temperature gradient of the bottom slab is an exponential function. The transverse temperature gradient in the middle of the web toward sunlight is apparent, whereas the gradients at other positions are small. Given the thermal difference effect, the longitudinal tension stress at the lower edge of the bottom plate and inside the web toward sunlight is high and should be considered in the design.

关 键 词：U形梁 日照温度场 温度梯度 温差效应 温度自应力 数值模型 轨道交通 

分 类 号：U24[交通运输工程—道路与铁道工程]