水电站厂房大体积混凝土温度应力分析与防裂措施

Analysis of thermal stresses and crack control measures in mass concrete of hydropower station powerhouse

针对厂房混凝土结构施工期易开裂的问题,采用三维非稳定温度场及应力场的有限元计算方法,对某水电站厂房下部大体积混凝土结构的施工全过程进行数值模拟,揭示其温度场及应力场的发展过程和分布规律,并根据计算结果提出切实可行的温控防裂措施。经分析发现,在低温入仓的基础上,采取表面保温和内部导热降温相结合的温控防裂措施,可有效降低混凝土早期的内外温差和后期的温降幅度,从而提高厂房混凝土的抗裂安全性。

The concrete structure of hydropower station powerhouse can easily crack during the construction period.In this paper,three-dimensional finite element method with unsteady temperature and stress field was used to simulate the whole construction process of the under part concrete structure of a hydropower station powerhouse.The development process and distribution regularity of the temperature field and stress field were obtained,and the feasible temperature control and crack prevention methods were proposed according to the computation results.The analysis showed that on the basis of low temperature before concrete pouring,temperature control and crack prevention measures with surface heat preservation and internal heat conduction can effectively decrease the temperature difference between the internal and external early-age concrete,and also decrease the temperature amplitude of later-age concrete,which can improve the safety against cracking of the powerhouse concrete.