高速磁浮大型箱梁日照温度效应分析

Sunlight Temperature Effect Analysis of Large-scale Box Girder of High-speed Maglev

磁浮系统对于轨道梁的温度变形控制要求极高,现有规范对于温度梯度的规定没有考虑不同地区气候因素的影响。在已有文献试验数据的基础上,验证有限元拟合箱梁温度效应的正确性,建立磁浮箱梁有限元模型,研究日大气环境下箱梁在上海与青岛两地的温度效应,在此基础上研究风速对于箱梁温度梯度的影响。结果表明:不同地区由于日照辐射、风速、大气温度等因素的不同,箱梁的竖向与横向最不利温差大小不一致,但温差分布趋势一致;竖向与横向温差梯度与规范相比存在一些区别,主要表现为温差不是单方向减小;3种方法计算的竖向温度变形中,拟合公式由于没有考虑箱梁横向温度梯度,其计算的竖向温度变形最小,规范公式与三维模型计算结果相近;风速对于箱梁的温差有较大影响,风速越大,温差越小,实际工程应考虑当地风速的大小。

The control of temperature deformation of the maglev guideway is very strict,and the existing norms do not take into account the impact of climate factors on temperature gradients in different regions.Based on the existing experimental data,this paper verifies the correctness of the finite element method.Then the finite element model of box girder is established to study the temperature effects of box girders in Shanghai and Qingdao.Based on this,the effect of wind speed on the temperature gradient of box girder is studied.Influenced by such factors as solar radiation,wind speed,and atmospheric temperature in different regions,the most unfavorable vertical and horizontal temperature difference of the box girder varies,but the trend of temperature distribution is consistent.The vertical and horizontal temperature gradients are somewhat different from the norm,mainly because the temperature difference is not reduced in one direction.Among the temperature deformations calculated by the three methods,the result calculated by the fitting formula is smaller without considering lateral temperature difference,while the result of norm is similar to the 3D model.Wind speed has a great influence on the temperature deference of the box girder.As the wind speed increases,the temperature difference of the box girder decreases,so the local wind speed should be considered in actual project.