【作者】 李秀才；

【导师】 陈应波；

【作者基本信息】 武汉理工大学 ， 结构工程， 2003， 硕士

【摘要】 大体积混凝土结构在浇筑过程中，由于受到内外温度变化的影响，从而导致混凝土体内或表面形成裂缝。研究裂缝的产生与发展机理和温控防裂措施是大体积混凝土结构设计与施工中十分重要的课题。只有充分掌握大体积混凝土的力学性能和裂缝的形成机理，才能更好地防止裂缝的产生。由于大体积混凝土的离散性和本身的特殊性，使得目前对裂缝产生的机理研究还不成熟。本文从微观力学和断裂力学的角度，探讨了混凝土结构开裂机理，分析了温变过程中混凝土骨料与水泥砂浆界面上的温度应力以及界面裂纹的萌生和扩展，给出了裂缝随温度变化的扩展规律。通过巴东长江大桥承台大体积混凝土配合比试验实例，给出了大体积防裂混凝土配合比的设计思路和原材料选择的理论依据。通过对巴东长江大桥施工现场主墩承台的温度和应力测试结果分析，研究了大体积混凝土内部温度场和温度应力场变化规律。实例证实：通过对大体积混凝土的原材料选择和配合比的优化设计，不仅能保证大体积混凝土的设计要求，也实现了大体积混凝土防裂的目标。 最后在有限元分析程序ANSYS的通用平台上，通过参数设计语言(APDL)以及多种ANSYS内部函数，编制宏命令来控制ANSYS程序进行施工温度场和温度应力场仿真。对巴东长江大桥承台大体积混凝土的浇筑温度场和温度场进行仿真分析，并将计算结果与实测结果进行了比较，结果显示用本文所建立的有限元分析模型可以较好地仿真实际混凝土温度场和温度应力场。更多还原

【Abstract】 In the process of mass concrete casting, defects will be produced such as micro cracks of surface and inside resulting from the different temperature between the surface and the inside. The study of the mechanism of crack generating and proceeding and the crack control method is a very important subject in the design of construction and the practical construction scheme. If we could grasp the basic mechanical behavior of mass concrete and the mechanism of crack generation, crack can be avoided. As the result of mass concrete’s discrete and peculiar character, the study of the mechanism of crack generation and propagation of mass concrete is still under scrutiny. In the view o6f micro mechanics and fracture mechanics, the mechanism of crack generation of mass concrete is expatiated, thermal stress on the interface between aggregate and cement paste of concrete and crack forming and developing is analyzed and the disciplinarian crack developing with temperature is given. Through the actual mix design test of mass concrete for the Badong Yangtze Bridge pile-cap, this article elaborated on the procedure of the mix design of mass anti-crack concrete and the theoretical foundations of the choice of concrete’s raw materials in detail. The analysis of the testing data of temperature and thermal tress at the base slab of the Badong Yangtze Bridge, study the regulation for changing of internal temperature field and thermal stress field of mass concrete. Through the choice of pile-cap concrete’s raw material and the mix optimization design, it is concluded that the mix design of mass concrete not only satisfy all the design requirements, but also attain the anti-crack concrete.Finally, based on the common-purpose flat of ANSYS, the macro file, which can simulate the temperature field and the thermal stress field, is compiled in this paper by using ANSYS Parametric Design Language (APDL) and many internal functions of ANSYS. The temperature field and the thermal stress field of the Badong Yangtze Bridge pile-cap is simulated and the computational results are compared with the experimental results. The results show that the finite element model in this paper is correctly set to simulate the temperature field and the thermal stress field of the concrete in practice.更多还原