炎热气候条件下筏板基础大体积混凝土防裂分析

Cracking Analysis for Mass Concrete to Raft Foundation in Hot Weather Conditions

从混凝土自身材料、施工过程、养护方案等方面简要论述了筏板基础大体积混凝土在炎热气候下施工时温度应力控制要点。通过对混凝土自浇注完成后20d的温度实测数据进行研究,绘制了混凝土沿筏板不同高度截面上温度发展的时程规律。分析了混凝土内外温差、表面与大气间的温差时程曲线及降温速率等参数的特点。对该大体积混凝土进行防裂验算,指出了温度应力裂缝最可能出现的时间点。

The key points for controlling thermal stresses of mass concrete of raft foundation in hot weather are addressed from the aspects of concrete material, process control , and maintenance scheme, etc. By study to the measured temperature data after 20d concrete maintenance, the time-history curves were plotted for the concrete temperatures in different height sections of the raft foundation. The characteristic parameters such as inside and outside concrete temperature difference, the difference between concrete surface and atmosphere, cooling rate,etc were described. By crack checking, the time that temperature stress cracks were most likely to appear is pointed out.