泵站后浇带混凝土温度场及温度应力场数值分析

Numerical analysis on temperature and temperature stress field of post-casting belts concrete in pumping station

为确定泵站后浇带施工方案,控制温度裂缝,通过对ABAQUS软件二次开发,分析了泵站后浇带混凝土结构施工过程中的温度场和温度应力场。利用用户子程序DFLUXT来定义混凝土水化热的产生,利用子程序FILM来定义混凝土浇筑及养护过程中的环境温度变化情况,利用子程序UMAT来进行混凝土的徐变及应力场的模拟分析,对湖北省洪湖螺山水电站泵站主泵房后浇带混凝土进行有限元分析,模拟结果与实测结果吻合度达到90%以上,且中心位置的模拟精度可达95%,可准确计算泵站后浇带结构施工过程中的温度场和温度应力场。通过提取后浇带混凝土内部特征点的温度场和应力场分析结果发现:厚度方向温度的最大值出现在混凝土中点位置偏下约20 cm处;温度应力最大值出现在混凝土上表面处,且温度应力在距混凝土上表面10 cm的位置开始急剧增长。

In order to develop construction schemes of post-casting belts concrete of pumping station and control temperature cracks,we analyzed temperature field and temperature stress field in the construction process of the post-casting belt through secondary development of ABAQUS.In the process of post-casting belts concrete numerical simulation,production of cement hydration heat was defined by user-defined subroutine DFLUXT.Environment temperature changed in the process of concrete pouring and curing were defined by user-defined subroutine FILM.Concrete creep and stress field simulation were carried out by user-defined subroutine UMAT.Then,we analyzed post-casting belts concrete of Luoshan pumping station,Honghu City,Hubei Province by finite element model.It was found that results of finite element analysis agreed well with measured results(goodness of fit more than 90%).The accuracy of simulation results in the center of the concrete was up to 95%,which showed that temperature field and temperature stress field of post-casting belts concrete during construction can be calculated accurately by finite element model.By analyzing temperature field and temperature stress field of measure points,the results showed that maximum temperature appeared at 20 cm below midpoint of post-casting belts concrete in the direction of thickness.Maximum temperature stress appeared on the surface of the concrete,and temperature stress started to grow dramatically 10 cm from the top surface of the concrete.