低温季节泵送混凝土结构施工期温控防裂研究

Research on Temperature Control and Crack Prevention of Pumped Concrete Structures During Construction in Low Temperature Season

低温季节施工时针对泵闸等结构泵送混凝土防冻与防裂的技术难题,以SYG工程为例,结合工程实际施工过程及现场温控监测成果进行大体积泵送混凝土温控防裂反馈分析;对比分析了不通水工况与实际通水工况下的应力曲线与混凝土容许拉应力曲线,并结合现场温控过程中存在的主要问题探讨了低温季节下泵闸工程的温控防裂技术.结果表明,在-8℃的较低温度下,采取充分的水管冷却和严格的表面保温措施可有效控制结构内部最高温度、内外温差以及最大拉应力水平,减小水闸结构开裂风险.本工程温控实践经验可为类似条件下的泵闸工程提供参考.

Aiming at the technical problem of frost protection and crack prevention for the pumping concrete of pump and sluice structures during the construction period in low temperature season,taking SYG project as an example and considering the field monitoring results of temperature control,the feedback analysis of temperature control and crack prevention of mass pumped concrete is carried out.The stress curves under the conditions of no water flow and the actual water flow are compared with the allowable tensile stress curve of concrete,and concerning the problems existing in the practical application,the temperature control and crack prevention technology of pump gate engineering is discussed for projects constructed in low temperature season.Results show that the maximum internal temperature,the temperature difference between inside and outside,and the maximum tensile stress of concrete can be effectively controlled by adequate water pipe cooling and surface insulation measures.The risk of cracking of sluice structure can be reduced,even under the low temperature of-8℃.The practical experience of temperature control measures here can provide reference for sluice and pump projects under similar conditions.