倒T字型混凝土薄壁结构施工期温度裂缝控制研究

针对倒T字型混凝土薄壁结构特点以及施工期易产生裂缝这一问题，阐述了裂缝成因和开裂机理,提出了相应的防止措施。倒T字型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是防止这类裂缝的有效温控措施。基于Arrhennius方程，采用水化度理论预测了温度和龄期对混凝土基本热学和力学性能发展的影响规律，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，对某－实际工程进行了仿真计算分析。计算结果表明在表面保温和内部水管降温相结合的温控措施下，防裂效果良好。该措施对类似工程具有一定的参考价值。

Study on thermal cracking control of Inverted T-shaped concrete structures during construction

In view of the problem of concrete crack in the period of construction, this paper introduces the forming mechanism of crack in inverted T-shaped and thin-walled concrete structure and puts forward the corresponding measures and methods. Generally speaking, the difference between the inside and out side temperature at the early stage and the basic difference of the temperature at the later stage are considered as the main factors, while the external heat preservation and internal cooling pipes measures have positive effect for preventing cracks. A theory of degree of hydration based on Arrhenius law was proposed to predict the development of concrete basic thermal and mechanic properties with temperature and age, and 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.