混凝土Weibull统计尺寸效应理论模型改进研究

随着工程结构中混凝土构件尺寸的不断增大，大尺寸混凝土构件强度尺寸效应研究变得日益重要。Weibull统计尺寸效应理论是解释混凝土尺寸效应的重要理论，它存在两大缺陷：一是混凝土材料均质度取值方法不完善；二是最弱链式串联破坏模型夸大体积作用，上述问题导致Weibull统计尺寸效应模型不完备。基于此本项目拟开展混凝土Weibull统计尺寸效应理论改进研究。揭示加载方式、骨料粒径对混凝土材料均质度的影响规律，探索研究多参量耦合的混凝土材料均质度动态取值方法；针对最弱链式串联破坏模型的局限性，研究大尺寸混凝土构件强度尺寸效应机理，探索提出基于体积修正的最弱链式串联破坏模型，改进混凝土Weibull统计尺寸效应理论。最后进行数值实验验证研究，验证上述方法的有效性和可行性，为大尺寸混凝土构件分析与设计提供理论依据。

With the increasing size of concrete elements in engineering structure, the research on size effect for the concrete elements is becoming increasingly important.. Two defects are confirmed for the Weibull statistics size effect theory. Firstly, the computation method of concrete homogeneity parameters is not accurate. Second, the effect of volume is exaggerated in the weakest link failure model .For the defects, the Weibull statistics size effect theory of concrete should be corrected. The research is implemented to improve the Weibull statistics size effect theory of concerte. Through the size effect experiments of concrete elements, the material homogeneity parameter influenced by loading mode and aggregate size is studied. The dynamic calculation method of concrete homogeneity parameters is educed. In view of the limitation of the failure model,the weakest link failure model corrected by volume is put forward , the size effect mechanism of concrete is studied . Based on the above researchs, the Weibull statistics theory of concrete is improved. Finally, the comparison numerical experiment is implemented to verify the feasibility of mechanism and the validity of the model which provides theoretic foundation for the analysis and design of large size concrete elements.