大体积混凝土温度裂缝控制机理与应用方法研究

发布时间：2018-01-15 08:24

本文关键词：大体积混凝土温度裂缝控制机理与应用方法研究　出处：《西安建筑科技大学》2013年博士论文　论文类型：学位论文

【摘要】：大体积混凝土温度裂缝问题一直是工程界长期关注，并致力于迫切解决的重要课题之一。本文在前人工作基础上，从理论和应用两个角度出发，对大体积混凝土温度裂缝控制机理与应用方法进行了深入研究，主要内容如下：（1）对大体积混凝土温度裂缝产生的机理主要从以下几个方面进行了研究，首先分析了大体积混凝土裂缝控制关键因素;然后对温度应力和约束变形进行了分析研究，总结出大体积混凝土结构在内、外约束作用下温度应力计算公式，阐述了约束对徐变松弛、弹性模量的影响。最后对大体积混凝土结构徐变应力进行了分析，建立了单向应力作用下的应力增量—应变增量关系式。（2）针对现行《大体积混凝土施工规范》（GB50496-2009）某些方面存在不足，提出在大体积混凝土配合比优化设计时，将一定比例的乳化沥青混合料掺入到大体积混凝土中作为外加剂，对掺有乳化沥青、粉煤灰和化学纤维的新型复合式大体积混凝土进行了原材料优选和配合比优化设计。对新型复合式大体积混凝土立方体抗压强度、轴心抗压强度、劈裂抗拉强度、静力受压弹性模量、轴向拉伸变形进行了力学性能试验，得出了一些有价值的结论和建议。（3）根据“抗—放”原理，建立了“抗—放”结合弹性滑动模型，并进行了力学分析和计算。针对弹性滑动模型在深部矿井井壁大体积混凝土裂缝控制研究领域存在的一些空缺，分析了深部冻结井壁高性能大体积混凝土的水化性能、温度状况和温度应力情况，构造出高性能大体积混凝土井壁温度场数学模型，建立了高性能大体积混凝土井壁变形基本微分方程，并将高性能大体积混凝土井壁裂缝控制新技术应用到工程实践中，得到了较好的社会效益和经济效益。（4）大体积混凝土温度场属于不稳定温度场。由于大体积混凝土浇筑层方向尺寸远小于水平方向尺寸，只有在厚度方向才能表现传热，大体积混凝土比较适合采用差分法进行计算;通过分析大体积混凝土热传导原理及热传导方程的边界条件，建立了大体积混凝土一维温度场有限差分法的计算模型，并结合具体工程进行了一维温度场有限差分法计算。（5）针对传统大体积混凝土温度裂缝控制中所使用冷凝管存在一些问题，结合“抗—放”原理，根据铝塑管特点，对埋设铝塑管的大体积混凝土裂缝控制方面的关键技术进行了系统研究。主要有铝塑管作为冷却水管的设计要求，铝塑管作为冷凝管时混凝土流变模型的建立，，在温度应力作用下，大体积混凝土中铝塑管的应力应变关系，并对施工中铝塑管抗浮问题进行了分析验算。（6）分析了大体积混凝土温度裂缝控制采用变形缝的不足，提出了在大体积混凝土内部埋设铝塑管作为内部变形管道，起到了控制温度裂缝和保证大体积混凝土结构整体性的双重作用。针对大体积混凝土中埋设铝塑管可能导致截面削弱等问题，对埋设铝塑管垂直方向、顺着铝塑管方向的大体积混凝土进行了等效惯性矩和等效宽度计算，对铝塑管柔性释放缝变位进行了分析，计算出铝塑管通过变形吸收的应变能，研究了铝塑管与混凝土之间变形能量耗散问题，得出了一些可供参考的结论和建议。
[Abstract]:The problem of large - volume concrete temperature crack has been a long - term concern of the engineering community and is one of the most important tasks to solve urgently . In this paper , based on the previous work , this paper studies the mechanism and application method of temperature crack in large volume concrete from two angles : theory and application . The main contents are as follows : ( 1 ) The mechanism of large - volume concrete temperature crack is studied mainly from the following aspects : firstly , the key factors of large - volume concrete crack control are analyzed ; then , the temperature stress and the constraint deformation are analyzed and studied , and the influence of the constraint on creep relaxation and elastic modulus is summarized . Finally , the creep stress of the large - volume concrete structure is analyzed , and the stress increment - strain increment relation under one - way stress is established . ( 2 ) In view of the deficiencies in some aspects of the existing large - volume concrete construction specifications ( GB50496 - 2009 ) , it is proposed that a certain proportion of emulsified asphalt mixture is incorporated into the large - volume concrete as an admixture in the design of large - volume concrete mix ratio optimization . The optimum design of raw materials and mix ratio is carried out for the novel composite large - volume concrete mixed with emulsified asphalt , fly ash and chemical fiber . The mechanical property test is carried out on the compressive strength , axial compressive strength , splitting tensile strength , static pressure compression modulus and axial tensile deformation of the novel composite large - volume concrete cube , and some valuable conclusions and recommendations are obtained . ( 3 ) According to the principle of " anti - caving " , the elastic sliding model of " anti - caving " is established , and the mechanics analysis and calculation are carried out . For the elastic sliding model , the hydration performance , temperature condition and temperature stress condition of high - performance large - volume concrete in deep well wall are analyzed . The mathematical model of temperature field of high - performance large - volume concrete well wall is analyzed . The basic differential equation of high - performance large - volume concrete well wall deformation is constructed . The new technology is applied to engineering practice for controlling the crack control of high - performance large - volume concrete well wall . ( 4 ) The temperature field of large volume concrete belongs to the unstable temperature field . Because the dimension of large volume concrete pouring layer is much smaller than horizontal dimension , heat transfer can only be carried out in the thickness direction , the comparison of large volume concrete is suitable for calculation by means of differential method , and the calculation model of one - dimensional temperature field finite difference method of large volume concrete is established by analyzing the heat conduction principle of large volume concrete and the boundary condition of heat conduction equation , and the finite difference method of one - dimensional temperature field is calculated in combination with the specific engineering . ( 5 ) According to the characteristics of aluminum plastic pipe , the key technology of large volume concrete crack control in large volume concrete is systematically studied according to the characteristics of aluminum plastic pipe . The stress and strain relation of aluminum plastic pipe in large volume concrete under the action of temperature stress is analyzed . ( 6 ) In this paper , the deficiency of temperature crack control with large volume concrete is analyzed , and the double effect of embedding aluminum plastic pipe in large volume concrete as internal deformation pipeline is put forward . The equivalent moment of inertia and equivalent width are calculated for large volume concrete embedded in large volume concrete , and equivalent moment of inertia and equivalent width are calculated for the large volume concrete embedded in the aluminum plastic pipe . The displacement of flexible releasing seam of aluminum plastic pipe is analyzed . The energy dissipation problem of deformation energy between aluminum plastic pipe and concrete is calculated . Some conclusions and suggestions are obtained .

【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU755.7

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