薄壁混凝土结构施工期温控防裂研究

Study on temperature control and crack prevention of thin-walled concrete structures during the construction period

针对施工期薄壁混凝土结构易开裂的问题,阐述了裂缝成因和开裂机理,提出了相应的防止措施.认为薄壁混凝土结构早期的内外温差,后期基础温差是这类裂缝产生的主要原因,而表面保温和内部水管降温的温控防裂措施是防止这类裂缝的有效措施.结合混凝土温度场应力场的基本原理和水管冷却的精确算法,通过三维有限单元法对某大型渡槽施工期混凝土结构在该温控防裂措施下的温度场和应力场进行仿真计算,结果显示该防裂措施效果良好,对类似工程具有一定的参考价值.

In view of the problem of concrete crack in the period of construction, this paper introduces the forming mechanism of crack in thin-walled concrete structure and puts forward the corresponding measures and methods. Generally speaking, the difference between the inside and outside temperature at the early stage and the basic difference of the temperature at the later stage are considered as the main factors influencing the phenomena, while the external heat preservation and internal cooling pipes measures have positive effect for preventing cracks, under the basic theories of temperature field and. stress field of concrete, the 3-D FEM with the numerical algorithm of pipe cooling is adopted to simulate the thermal field and stresses field of concrete aqueduct during construction. The result shows that good effect of temperature control and crack prevention is achieved. This should have great reference significance to the similar concrete projects in the future.