混凝土单箱双室磁浮轨道梁的日照温度场分布研究

Temperature Field Analysis of Concrete Twin-celled Single Box Maglev Guideway Caused by Solar Radiation

日照作用下混凝土单箱双室磁浮轨道梁的温度场分布不均匀,易引起变形、开裂,影响轨道平顺性及行车安全性。基于传热学原理,结合上海夏季辐射和气温等气象资料,针对日照作用下混凝土双室箱梁的温度场分布展开有限元模拟分析,研究了不同时刻时轨道梁截面的温度分布规律,得到了箱梁在不同时刻的温度云图;提取最大竖向温差时刻腹板和最大横向温差时刻底板中线的温度值,拟合后得到横向与竖向的温度梯度曲线,与规范温度梯度对比后发现:竖向温度梯度峰值比规范值大,变化更加剧烈,且在底板附近存在反向温差,横向温度梯度峰值比规范值小,变化也更加剧烈且同样存在反向温差,双室箱梁的温度梯度模式与规范不一致。

The temperature field of concrete twin-celled single box maglev guideway caused by solar radiation is not uniform,which is likely to cause deformation and cracking,affecting track ride comfort and driving safety. Based on the principle of heat transfer and with reference to meteorological data of summer radiation and temperature in Shanghai,temperature field distribution of single box and double room concrete beam at different time caused by solar radiation is simulated by finite element method and images of temperature field at different time are obtained. The temperature values at the center line of the middle web and the bottom plate are obtained respectively with the maximum temperature difference, then the curve oftemperature gradient is obtained after fitting. The comparison with the specified temperature gradient shows that the peak value of vertical temperature gradient is larger than normal value,it changes more violently and there is reverse temperature difference near the bottom plate. The transverse temperature gradient peak is smaller than the standard value,the temperature change is more intense and the reverse temperature difference exists. The temperature gradient pattern of the double chamber box girder is inconsistent with that in the code.