表面保温对施工期闸墩混凝土温度和应力的影响

对于严寒季节施工的混凝土工程,常采用各种表面保温措施以防止裂缝的产生.针对水闸这一典型的水利工程结构,分析水闸施工期闸墩混凝土温度和应力变化规律与开裂机理,阐述了不同表面保温措施对闸墩混凝土温度和应力的影响.研究结果表明,较强的表面保温可以大大减小闸墩混凝土早期内外温差和表面拉应力,防止产生表面裂缝,但同时使得后期闸墩内部拉应力增大,产生贯穿性裂缝的可能性增加.对于不同的工程,应通过数值仿真计算选择适合本工程的表面保温措施,以减小混凝土开裂的可能性.

Effect of surface heat preservation on temperature and stress of pier concrete during construction period

In concrete engineering,measures of surface heat preservation are often used to prevent cracks in concrete in severe cold season.Aiming at the typical structure of sluice in hydraulic projects,an analysis was made of the mechanism of cracking and regularity of temperature and stress variation in pier concrete,and the effects of different surface heat preservation measures were expounded.The results show that the adoption of heat preservation measures can effectively prevent cracks in pier surface by decreasing the difference between the inside and outside temperatures at early stage and the tensile stress of concrete surface,but it increases the internal tensile stress at later stage,and therefore,results in a high probability for occurrence of penetration cracks.As for different projects,suitable surface heat preservation measures should be selected by numerical simulation so as to reduce the probability of cracking in concrete.