倒T型混凝土薄壁结构施工期温度裂缝控制研究

针对倒T型混凝土薄壁结构特点以及施工期易产生裂缝这一问题，研究了裂缝成因和开裂机理，提出了相应的防止措施。倒T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计算方法，对某一实际工程进行了仿真计算分析。计算结果表明，表面保温和内部水管降温相结合的温控措施，裂效果良好。

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

The mechanism of crack in inverted T shaped thin walled concrete structure in the period of construction was investigated and the corresponding measures for crack preventing were proposed. It was found that the temperature difference between the surface and interior of concrete structure at the early stage and the temperature difference between structure and foundation at the later stage are the main factors influencing the occurrence of cracks. The exterior thermal insulation and interior cooling are the effective measures to prevent the concrete structure from cracking. The Arrhennius equation based on degree of hydration is used to study the impacts of temperature and age on the thermal and mechanical properties of concrete. A concrete aqueduct in the process of construction is numerically simulated by using 3 D FEM involving the exterior thermal insulation and the interior cooling pipes. The result verifies the effectiveness of the measures proposed in this paper.