索塔承台大体积混凝土温度及应力场监测与有限元分析

Monitoring and finite element analysis of temperature and stress field of mass concrete for tower platform

为控制浇筑后大体积混凝土内表温差过大及温度裂缝的产生,了解混凝土内部温度及应力场的分布与变化规律,通过对某大体积混凝土承台温度及应力进行现场监测,结合有限元模拟分析冷却管冷却下,大体积混凝土施工中温度及应力场的变化与分布规律。研究结果表明:承台大体积混凝土浇筑后,在2~3 d达到温度峰值,其不同区域温度先后达到峰值的顺序为:侧表面、上表面、内部;侧表面与内部最大温度差值出现时间较上表面与内部最大温度差值出现时间早;混凝土内部最高温度区域主要集中在相邻两冷却管中间,其温度沿冷却管水流方向有增高趋势,冷却过程中应定时变换冷却水流向;混凝土内部应力随时间变化先后以线性增加、抛物线(开口向上)变化和线性减小的趋势呈现。本文研究结果对大体积混凝土温控设计与施工具有一定的参考价值。

In order to control the excessive temperature difference between the inner surface and the outer surface of mass concrete and the generation of temperature cracks after pouring,it is of vital importance to analyze and understand the distribution and variation of temperature and stress field inside the concrete.Combined with the in-situ monitoring and the method of finite element simulation,the change and distribution of temperature and stress field in a massive concrete platform under the cooling of cooling pipe during construction was analyzed.The results are as follows.The temperature peaks are reached in 2 to 3 days after the mass concrete is poured,and the peak value successively according to the side surface,upper surface and interior in different areas.The maximum temperature difference between the side surface and the interior occurs longer than the internal maximum temperature difference appears early.The maximum temperature inside the concrete is mainly concentrated in the middle of two adjacent cooling pipes and the temperature tends to increase along the direction of water flow in the cooling pipe,and the cooling water flow direction should be changed regularly during the cooling process.The internal stress of the concrete varied with time show the successive tendency of linear increase,parabolic variation of opening upward and linear decrease.Results of this research have certain reference value for the temperature control during the design and construction process of massive concrete.