保温浇筑对蜗壳外围混凝土温控性能的影响分析

针对蜗壳结构外围混凝土的施工特点,在考虑水化热温升的基础上,采用水体控温、分层浇筑、顺序耦合等技术实现了水电站保压蜗壳结构施工期的瞬态温度场和应力场的分析,探讨了保温浇筑对蜗壳外围混凝土早期温控性能的影响.结果 表明:混凝土水化热所释放的热量对早期温控性能的影响占主导地位.采取蜗壳内水体控温的保温浇筑措施,其效果并不明...

Influence of Internal Water Heat Preservation for Surrounding Concrete of Spiral Case during Pouring Period

According to the construction characteristics of spiral case structure, the transient temperature field and stress field of the pressure retaining spiral case structure in hydropower station were analyzed by adopting the techniques of water temperature control, layered casting and sequential coupling on the basis of considering the temperature rise of hydration heat. The results show that the influence of early temperature control performance is dominated by the hydration heat of cement. The influence of internal water heat preservation in the pouring period is not obvious. However, the lower initial pouring temperature can effectively improve the temperature field and stress field of the structure in the whole phase. The influence of internal water heat preservation in the pouring period emerged gradually until the later pouring period (after 28 days), and the effect and scope of influence were limited. Moreover, although the heat preservation casting played the temperature control effect of "internal reduction and external protection" for the concrete inner boundary attached to the steel lining, it slowed down the cooling rate of the whole concrete and indirectly increased the tensile stress on the concrete outer surface. Consequently, in the construction stage of water-filled and pressure-retaining spiral case structure, not only the construction method of heat preservation and pressure-holding should be adopted, but also the warehousing temperature of concrete should be effectively controlled, such as mixing with ice water, pre-cooling aggregate, heat preservation transportation and other measures.