高速铁路箱梁-无砟轨道结构温度场模型的级数解

Series solution of thermal field model of box girder ballastless track structure in high-speed railways

为了预测高速铁路箱梁-无砟轨道结构的温度场分布及升温模式,结合箱梁-无砟轨道结构的实测温度和气象参数,建立第三类边界条件的温度场预估模型。基于热阻网络法分析箱梁-无砟轨道结构的复合换热过程,采用积分变换法求得结构升温过程的级数解,并结合预估模型对箱梁-无砟轨道结构升温模式进行分析。研究结果表明:采用积分变换法求得结构升温过程的级数解,其前8项求和结果与数值结果和实测结果的最大误差分别为5%和8%;当辐射气温大于混凝土结构表面温度时,可采用半无限域温度场模型近似计算表面温度,与有限域模型的温度级数解的相对误差在1℃之内;高速铁路箱梁-无砟轨道结构的四折线及指数温度模式与实测温度模式拟合度很高,可满足实际工程应用。结构指数温度模式的计算公式可预测不同截面高度、不同工况(施工、运营)的结构升温模式。

To predict the thermal field distribution and the heating model of box girder-ballastless track structure in high-speed railways, a prediction model of the thermal field with the third type boundary condition was established using the experimental temperature of the box girder-ballastless track structure and the meteorological parameters. The composite heat exchange process of the box girder-ballastless track structure was analyzed based on thermal resistance network method. The series solution of the thermal field was obtained by the integration transformation method. The predictive model was used to analyze the heating model of the box girder-ballastless track structure. The results show that the maximum relative errors between the sum of the first eight terms and the experimental data and the simulation result are 5% and 8%, respectively. When the radiation temperature is greater than the surface temperature of the concrete structure, the approximate solution of thermal field model of the semiinfinite domain can be used to calculate the surface temperature, and the error is controlled within 1 ℃ compared to the series solution in the finite domain. The four-fold-line thermal model and exponential thermal model for the box grider-ballastless track structure are proposed. Compared with thermal model from measured datas, the fit is good, which can meet the requirement of actual engineering application. The calculation formula of the structural exponential temperature model can be used to predict the heating model of structure with different cross-section heights and in different conditions such as construction and operation.