【作者】 胡奇；

【导师】 冯仲仁；

【作者基本信息】 武汉理工大学 ， 桥梁与隧道工程， 2009， 硕士

【摘要】 近年来,随着我国交通事业的发展,桥梁工程建设规模的增大,大体积混凝土水化热的控制问题已经引起桥梁工程界的高度重视。大体积混凝土在固化过程中释放的水化热会产生较大的温度变化和收缩而导致裂缝。而在桥梁施工中,常因防裂措施不当,导致混凝土温度应力超过其抗裂强度,造成混凝土开裂,影响混凝土的使用。虽然在混凝土大坝的设计、施工中对于大体积混凝土水化热温度场的研究有了长足的进步,但是目前能够结合桥梁的自身特点把各种因素对温度场的影响情况给较精确的计算出来的研究仍然是很必要的。本文以江西赣州飞龙岛大桥主塔承台大体积混凝土温度监测和裂缝控制为研究内容,系统开展了承台大体积混凝土温度控制研究。通过浇筑混凝土材料的选择,冷却循环水管的设置,控温保温养护措施的实施,对整个施工过程实时监控,实现了大体积混凝土施工的有效控制。承台混凝土浇筑完成后,未出现裂缝,达到了预期的监控目的。针对上述情况本文主要内容如下:(1)介绍水化热分析的理论基础以及一些主要参数的取值方法。从热传导基本原理出发,考虑大体积混凝土温度应力的主要影响因素,分析大体积混凝土结构中的温度作用原理,温度裂缝的产生机理、危害和控制方法,总结选取各种热学指标。(2)以飞龙岛大桥为工程背景,介绍大体积混凝土承台进行水化热温度控制的详细过程,并对其实测与计算的数据结果进行比较和分析。(3)运用三维有限元软件MIDAS/Civil对承台大体积混凝土,按照实际冷却水管的布置、水流情况、边界条件、实际施工过程等因素进行全程水化热温度场的仿真分析。通过对实测温度场和计算温度场的分析得出了许多有益结论。(4)提出并论证在夏季施工时,采用有效的温度监控措施可以更加有效的降低大体积混凝土中部的温度,使混凝土内温度变化更加均匀,减少混凝土内外的温差。更多还原

【Abstract】 In recent years,with the development of the national traffic and the expansion of bridge construction,the issue about the hydration heat control of mass concrete has attracted great attention of bridge engineering.Releasing steam heat from the mass concrete structures while solidifying leads to produce the temperature change and contraction.In bridge construction,inappropriate measures lead to thermal stress of concrete over the anti-crack strength,resulting in concrete cracking and impact the concrete work.Although the concrete dam design and construction of mass concrete in the heat of hydration temperature field of research has made substantial progress, but it is very necessary that the study which we combine the characteristics of a bridge between the various factors gives a more accurate calculation on the temperature field.This paper introduced systematically the temperature control program and monitor analysis of the results on mass concrete construction of main tower bank pier of feilong-island bridge in Jiangxi province.The project has achieved effective control of mass concrete construction through the choice of pouring concrete,the set of cooling pipes,the implementation of conservation measures and the real-time monitoring throughout the construction process.After the concrete was moulded, there was no crack in the bank pier.Practice shows that the temperature control method is effective.The main research work of this paper includes such aspects:(1) This paper introduces the basic theory of the heart of hydration analysis and considers the main influence factor of mass concrete temperature stress on the basic theory.This paper also analysis the temperature function principle,temperature crack development mechanism,danger,method of crack control in mass concrete and summaries the choose of different calorific indexes in mass concrete.(2) This paper introduces the detailed process what the temperature control about heat of hydration in mass concrete,analyzing and comparing the measured data with calculation results trough the feilong-island bridge project.(3) This paper has simulation analysis with the bank pier mass concrete by the finite element software,in accordance with the actual layout of the cooling pipes, water flow situation,the boundary conditions,the actual construction process factors. This paper has gotten many useful conclusions through the analysis about the data and the calculating results in temperature field.(4) This paper proposes and demonstrates the Effective temperature control measures can be more effective to lower the center of mass concrete temperature, making concrete a more uniform temperature change,reducing the temperature difference between inside and outside the concrete.更多还原