贯流式泵站施工期的温控防裂对策研究

Countermeasure Study on Temperature Control and Crack Prevention of Tubular Pumps During Construction Period

针对泵站结构施工期易开裂的问题,阐述了裂缝成因,提出了相应的防止措施.得出早期的内外温差和外部约束是产生表面裂缝的主要原因.采用了表面保温、水管冷却及设置砌体等方法来防止墩墙混凝土产生温度裂缝.利用水管冷却混凝土温度场和应力场的三维有限单元精确算法,对某大型贯流式泵站墩墙结构的施工期温控防裂进行了仿真计算,结果显示计算方法精确、防裂效果良好,对此类工程具有一定的参考价值.

In view of the problem of concrete crack of tubular pumps in the period of construction, the paper introduces the forming mechanism of cracks in pier-wall structures and puts forward corresponding measures and methods. Generally speaking, the temperature difference between the inside and the outside at the early age is considered as the cause of surface cracking; and external restrictions constrain concrete shrinkage in cooling phase and are considered as the cause of internal cracking, while the external heat preservation, internal cooling pipes and masonry measures have the positive effect of preventing cracks. Accurate numerical algorithm of pipe cooling temperature field and stress field of concrete structures and 3-D finite element method are adopted to simulate the temperature field and stress field of pumping station during construction. The result shows that the measures are good on crack prevention and have great reference significance to the similar concrete projects in the future.