时变对流模式下混凝土厚壁结构内生热场分布

Distribution of hydration heat temperature fields for concrete thick-wall structure exposed to time-dependent convection model

针对高墩混凝土箱梁墩顶块水化热温度场分布状况,考虑了风速的影响,建立了时变对流热传导模式,利用ANSYS分别对时变对流换热系数和稳定对流换热系数下混凝土箱梁墩顶块水化热温度场进行了分析,总结了时变对流模式下混凝土箱梁墩顶块水化热温度场的分布规律,并与实测值进行了对比。研究结果表明:时变对流计算模式适合计算高墩混凝土箱梁墩顶块的水化热温度场;混凝土箱梁墩顶块水化热温度分布以腹板、顶板、底板与横隔板的交合部分为球心呈层状向外逐渐减小;随着时间的延伸,水化热温度分布形状相似,相应区域内温度值降低;时变对流换热系数下水化热温度峰值出现时间约为56 h,稳定对流换热系数下水化热温度峰值出现时间约为80h;风速对各测点的水化热温度峰值及其发生的时间影响较大,增大风速可降低水化热温度峰值,缩减温度峰值出现的时间。

Aimed at temperature fields distribution problems of concrete box girders on high piers, the wind speed was considered, the time-dependent convection heat conduction model was built, the finite element procedure ANSYS was applied to analyze hydration heat temperature dis- tribution for concrete box girders under condition of the time-dependent convection coefficients and stable convection coefficient, the distribution laws of hydration heat temperature distribution for concrete box girders under condition of time-dependent convection heat conduction model was generalized, and the results were compared to the actual measurement value. The results indicate that. the time-dependent convection heat conduction model is adapt to calculate hydration heat fields of concrete box girders on high piers; the distribution of hydration heat temperature fields for concrete box girders gradually decrease from the inner to the outer as the centre of copulation parts for web plates and upper plates and floor plates and tabula plates; with extension of time, the distribution shape of hydration heat temperature fields is similar except its different value; the wind speed has an effect on peak value of hydration heat temperature, its occurrence time is about the 56 hours under condition of the time-dependent convection model, its occurrence time is about the 80 hours under condition of the stable convection model, the increment of wind speed can decrease the peak value of hydration heat temperature, and reduce its occurrence time. 1 tab, 5 figs, 13 refs.