无缝连续浇筑大体积混凝土温度控制及应变分析

发布时间：2018-05-27 20:05

本文选题：大体积混凝土 + 无缝连续浇筑　；参考：《西安建筑科技大学》2015年硕士论文

【摘要】：在工业与民用建筑结构中,大体积混凝土结构的推广应用越来越普遍,由于该类混凝土结构体积庞大、施工过程复杂,浇筑时间较长,需投入较多的人力、物力,施工难度大,因此对于施工过程的控制比较严格,如果控制不当,在混凝土结构表面或者内部将会产生有害裂缝,对混凝土结构的安全性造成不良影响,从而降低结构使用寿命。对于大体积混凝土的温度与应力控制问题,是建筑工程领域普遍关注的问题。通过现场实测和有限元模拟分析大体积混凝土结构的温度场以及应力场变化,根据得出的相关结论,为施工过程中安全薄弱部分提供实时的预警监控分析,指导施工养护措施的落实,从而避免有害裂缝产生,是目前许多重要结构工程常用的技术手段。本文以某实际工程基础筏板大体积混凝土浇筑过程为例,采取理论计算、有限元软件Madis模拟分析以及现场实测的方法,根据有限元分析结果,结合实际现场混凝土浇筑顺序;由于结构的对称性,选取一半结构进行布点监测,在易出现应力集中的位置布设应变传感器进行同步的监测,重点监控混凝土厚度较大的典型部位;通过有限元与实测的对比,得出以下结论:(1)在保温及防裂措施得当的情况下,对于大体积混凝土基础筏板可采用连续整体浇筑,不设后浇带的施工方法。养护过程中应根据温度以及应变实时监测数据对大体积混凝土进行动态养护,并加以弹性模量的实时跟踪养护监测,根据测温情况确定基础侧壁模板拆模时间以及采取相应保温保湿措施。(2)将有限元分析的结果与现场实测进行对比,得出二者规律相近的曲线,虽然数值略有差异,但总体趋势相似,实测结果中混凝土温度的发展趋势与有限元分析结果吻合,可见,在材料参数确定的前提下,有限元软件可以准确的模拟筏板基础大体积混凝土内部温升变化的发展情况,并以此为依据,预见温度场的变化情况,合理选择温控方法,控制有害裂缝的产生。(3)通过此次研究,在同类大体积混凝土施工中,可以在温度场和温度应力仿真应用Madis软件,得到最高温度和混凝土内部温度应力分布的近似计算,并以此为依据,预见温度场的变化情况,合理选择温控方法,控制有害裂缝的产生。
[Abstract]:In industrial and civil building structures, the popularization and application of mass concrete structures are becoming more and more common. Due to the large volume of such concrete structures, the construction process is complex, the pouring time is longer, it needs more manpower and material resources, and the construction is difficult. Therefore, the control of the construction process is strict. If the control is not proper, there will be harmful cracks on the surface or inside of the concrete structure, which will adversely affect the safety of the concrete structure, thereby reducing the service life of the structure. The temperature and stress control of mass concrete is a common concern in the field of building engineering. The change of temperature field and stress field of mass concrete structure is analyzed by field measurement and finite element simulation. According to the relevant conclusions, real-time early warning monitoring and analysis are provided for the weak part of safety in construction process. To guide the implementation of construction maintenance measures to avoid harmful cracks is a common technical means used in many important structural engineering at present. In this paper, taking the pouring process of mass concrete of raft slab of a practical engineering as an example, the method of theoretical calculation, finite element software Madis simulation analysis and field measurement is adopted. According to the results of finite element analysis, combined with the actual field concrete pouring sequence; Because of the symmetry of the structure, select half of the structure to monitor the points, and set up the strain sensor to monitor the typical parts of the concrete thickness in the position where the stress concentration is easy to occur, and through the comparison of finite element and the actual measurement, The following conclusion is drawn: (1) under the condition of proper heat preservation and crack prevention measures, the construction method of continuous integral pouring without post-pouring belt can be used for mass concrete foundation raft. In the course of curing, mass concrete should be dynamically cured according to the real-time monitoring data of temperature and strain, and the modulus of elasticity should be monitored in real time. According to the temperature measurement, the time of removing the mould of the base sidewall formwork is determined, and the corresponding measures of heat preservation and moisture preservation are taken. The results of the finite element analysis are compared with the field measurements, and the curves with similar laws are obtained, although the numerical values are slightly different. However, the general trend is similar. The development trend of concrete temperature in the measured results is consistent with the results of finite element analysis. It can be seen that under the premise of determining the material parameters, The finite element software can accurately simulate the development of temperature rise in the mass concrete of raft foundation, and based on it, we can foresee the change of temperature field and reasonably select the temperature control method. Through this study, in the construction of similar mass concrete, Madis software can be used to simulate the temperature field and the temperature stress, and the approximate calculation of the maximum temperature and the temperature stress distribution inside the concrete can be obtained. On the basis of this, the change of temperature field is predicted, and the temperature control method is reasonably chosen to control the generation of harmful cracks.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU755.7

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