大坝及湿筛混凝土拉伸软化本构关系研究

发布时间：2017-12-31 17:30

本文关键词：大坝及湿筛混凝土拉伸软化本构关系研究　出处：《浙江工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：混凝土的断裂过程区存在软化特性,根据虚拟裂纹模型,断裂过程区的本构关系用应力—裂缝张开宽度(σ-w)曲线,即拉伸软化曲线描述。混凝土拉伸软化曲线是评价混凝土断裂性能的重要指标:由σ-w曲线(称为软化曲线),经数值模拟分析,就可预测混凝土的宏观断裂行为。本文采用三峡大坝混凝土的施工配合比,制作不同强度、骨料粒径的8组40个大坝及湿筛混凝土试件进行直拉断裂试验。基于直接拉伸试验结果和混凝土断裂力学分析,由直拉法确定混凝土的软化关系表达式。采用相同的材料和配合比制作14组56个楔入劈拉试件,测试其荷载—裂缝口张开位移(P—CMOD)曲线,并基于改进进化算法的逆分析法确定混凝土软化曲线。对比逆分析法和直拉法得到的软化曲线,验证用逆分析法确定混凝土软化曲线的可行性。受试件尺寸和试验设备的限制,常采用湿筛混凝土试件来模拟测定原级配大坝混凝土的力学性能。但有关湿筛混凝土与大坝混凝土软化特性关系的研究较少。故,本文对比研究湿筛混凝土和大坝混凝土软化曲线的关系;同时,分析骨料粒径、水胶比对软化参数的影响规律。这为大坝混凝土软化性能的研究和裂缝防治提供参考。
[Abstract]:There is a fracture process zone softening characteristics of concrete, according to the virtual crack model, the constitutive relation of the fracture process zone with stress crack opening width (-w) curve, the tensile softening curve is described. The concrete stress-strain softening curve is an important index to evaluate the fracture properties of concrete by -w curve (called softening curve). By numerical simulation, macro fracture behavior can be predicted. The concrete construction of the Three Gorges dam concrete mix, making different strength, aggregate size of 8 groups of 40 dam and wet screening concrete direct tensile splitting test. Analysis of direct tensile test results and fracture mechanics of concrete based on by Czochralski method to determine the concrete softening relationship expression. Using the same material and mix 14 group 56 wedge splitting specimens, test the load CMOD curve (P - CMOD), and based on the improvement of The algorithm of inverse analysis method to determine the softening curve of concrete. The inverse analysis method and Czochralski method of softening curve comparison, the inverse analysis method to determine the feasibility of softening curve of concrete for verification. The specimen size and testing the limits of equipment, often using wet sieving concrete specimens to simulate the determination of the mechanical properties of fully graded concrete. But the research on wet sieving concrete and dam concrete softening relationship less. Therefore, the comparative study of the wet screened concrete and softening curve of concrete dam; at the same time, the analysis of aggregate size, influence of water binder ratio on softening parameters. It provides a reference for dam concrete research on softening and crack prevention performance.

【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TV642;TV431

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