多因素作用下的大体积混凝土裂缝产生原因及控制机理研究

发布时间：2018-11-05 21:07

【摘要】：大体积混凝土作为高层、超高层建筑所采用的大型基础之一,已经成为当今必不可少的工程施工项目。虽然在其施工技术、理论研究方面不断的在创新与发展,但是大体积混凝土作为大型的复杂结构,在其裂缝控制方面仍有许多尚未解决的技术难题。在建筑工程领域中,作为高层、超高层建筑的大型基础,多数是筏板基础。这种基础因其底板厚度及面积比较大,在浇筑完成后会由于各种不确定因素而产生裂缝,其中温度裂缝最为常见,也最为严重。所以对应其底板大体积混凝土温度裂缝的控制问题现已成为建筑工程领域所研究重点。大体积混凝土温度裂缝的产生是温度应力作用的结果,而温度应力的大小是由多因素影响下的,如水泥的水化热、外界温度、弹性模量、收缩变形等。不同条件下混凝土结构底板会产生不均匀的温度应力,当应力值逐渐加大,一旦超过混凝土极限拉应力,大体积混凝土结构基础底板就会由于受力不均产生温度裂缝,危害混凝土结构。本文结合具体工程,对基础底板大体积混凝土的研究主要有以下几个方面:(1)在查阅大量文献资料的基础上,对大体积混凝土结构内部温度应力和温度裂缝作分析研究。并总结该工程领域中的近年来国内外的发展现状及今后的发展趋势。(2)分析了大体积混凝土的温度裂缝产生的机理,以及从混凝土自身和其他各方面出发分析了影响大体积混凝土温度裂缝的主要因素。(3)对有限元仿真模拟的理论基础做详细介绍,利用温度场理论在对结构进行温度场分析的基础上进行温度应力场的模拟分析,实现温度—应力的耦合。(4)介绍ANSYS有限元软件的耦合场分析方法,重点介绍了耦合场理论中温度-应力的耦合。(5)结合具体工程实例,对大体积混凝土筏板基础的温度应力场的耦合作具体模拟计算,得出总结,分析仿真结果。并根据对温度应力影响下的结构应变位移进行模拟,并从模拟的结果中分析温度裂缝的产生及控制。
[Abstract]:Mass concrete, as one of the large foundations used in high-rise and super high-rise buildings, has become an indispensable engineering construction project. Although the construction technology and theoretical research are constantly innovating and developing, there are still many unsolved technical problems in the crack control of mass concrete as a large complex structure. In the field of building engineering, as a large-scale foundation of high-rise and super-high-rise buildings, most of them are raft foundations. Because of the large thickness and area of the bottom plate, the foundation will produce cracks due to various uncertain factors after pouring, among which the temperature cracks are the most common and the most serious. Therefore, the control of temperature cracks corresponding to the mass concrete in the floor has become the focus of research in the field of building engineering. The temperature crack of mass concrete is the result of temperature stress, and the temperature stress is affected by many factors, such as hydration heat of cement, external temperature, elastic modulus, shrinkage deformation and so on. When the stress value increases gradually, once the ultimate tensile stress of concrete exceeds the limit of concrete, the temperature crack of mass concrete structure foundation slab will be produced due to the uneven force. Hazardous concrete structure. In this paper, the research on the mass concrete of the foundation slab has the following aspects: (1) on the basis of consulting a lot of literature, the temperature stress and the temperature crack of the mass concrete structure are analyzed and studied. And summarizes the development of the engineering field in recent years at home and abroad and the development trend in the future. (2) the mechanism of temperature cracks in mass concrete is analyzed. The main factors affecting the temperature crack of mass concrete are analyzed from concrete itself and other aspects. (3) the theoretical foundation of finite element simulation is introduced in detail. Using the theory of temperature field, the temperature stress field is simulated and analyzed on the basis of analyzing the temperature field of the structure. (4) the coupling field analysis method of ANSYS finite element software is introduced. The coupling of temperature-stress in coupling field theory is introduced emphatically. (5) the coupling of temperature stress field of mass concrete raft foundation is simulated and calculated with concrete engineering examples, and the results are summarized and analyzed. The structure strain displacement under the influence of temperature stress is simulated, and the temperature crack generation and control are analyzed from the simulation results.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU755.7

【相似文献】