寒冷干旱地区高碾压混凝土坝裂缝成因分析

某高碾压混凝土重力坝地处寒冷干旱地区,施工中在其底部基础区发现裂缝。采用有限元法对裂缝坝段混凝土温度及应力变化过程进行了仿真分析。结果表明:混凝土应力与温度变化呈明显的负相关性,在混凝土升温阶段坝段内部应力以压应力为主,达到最高温度开始降温后逐渐出现拉应力区;持续时间在2 d以上的连续降温对混凝土表面的危害较大;混凝土表面保温对削减寒潮冷击的作用比较显著,能有效防止混凝土开裂。

Analysis on the Cause of Cracks of High RCC Dam in Cold and Arid Area

Cracks was found at the bottom of the foundation area of a high gravity RCC dam located in the cold and arid area during the construction.This paper simulated the changing process of temperature and stress of the concrete by applying the finite element method.The results show that,there is a significant negative correlation between the stress and temperature of the concrete.When the temperature rising it is compressive stress in inside of concrete but after reaching the highest the temperature begins to drop and the tensile stress appears gradually.More than 2 days of air temperature dropping is great harmful to the surface of the concrete.The surface heat preservation of the concrete can reduce the effect of the cold wave strike and also can prevent the concrete from cracking.