大型混凝土箱梁水化热温度场的数值模拟

Numerical Simulation on Hydration Heat Temperature Field of Large-size Concrete Box Girder

针对大跨径混凝土箱梁桥0号箱梁的特点,详细介绍分析了水化热温度场数值模拟过程中混凝土参数的取值以及边界条件的确定方法,以苏通大桥辅助航道桥的0号箱梁为例,利用ANSYS对其混凝土浇注后的温度场进行了数值模拟,并与实测值进行了对比。研究结果表明:混凝土硬化早期,温度随水泥水化的发展,经历了较快的温升阶段,到达最值后,进入缓慢的温降阶段,最值出现的越早,温降的速率越大;混凝土浇注后的最大内外温差与构件厚度和表面边界情况有关,构件厚度越大,表面散热条件越好,可达到的最大内外温差也就越大;新旧混凝土结合面处存在温度倒灌现象.混凝土养护期间,应根据箱梁混凝土水化热温度场的特点,对重要部位进行有针对性的养护。

According to the start element characteristics of long-span concrete box girder bridge,the determination of concrete parameters and boundary conditions in the numerical simulation process of the hydrated heat temperature field were introduced and analyzed in detail.Taken the start element of auxiliary channel bridge of Sutong Bridge for example,the simulation analysis of hydrated heat temperature field of the depositing period of start element was made by using ANSYS,and the comparison of the results of FEA with the measured values.The results indicate that（1） during the early hardening of concrete,with the development of cement hydration,its temperature experienced a phase of rapid rise,and then it dropped slowly when it reached the extreme value,the sooner the extreme value reached,the greater the rate of temperature dropping was;（2） the maximum temperature difference between interior and exterior after pouring was concerned with component thickness and boundary condition of surface,the thicker the component was,the greater the condition of the heat dissipation of surface was,and the bigger the temperature difference between inside and outside was;（3） the phenomenon of temperature intrusion in the combined surface of old and new concrete existed.Thus,during the curing concrete,the maintenance of important parts should be kept targeted in accordance with the characteristics of box girder concrete hydration heat temperature field.