循环荷载下混凝土应力-应变全曲线研究

利用三峡大学自行研发的大型多功能静动力三轴仪对混凝土试件进行了不同加载速率下的循环加卸载试验。通过对混凝土循环加卸载曲线的包络线与共同点轨迹线进行比较分析,发现共同点轨迹线与包络线形状大体相似,并且可以通过包络线峰值点与共同点轨迹对应值,以及包络线方程,可推断出共同点轨迹线。基于试验数据和对混凝土循环加卸载全曲线的理解,分析了循环加卸载中单个加载和卸载曲线的变化特征,构建了循环加卸载下混凝土应力-应变全曲线方程数学模型,结果表明:所建立模型能够很好地描述循环加卸载下混凝土的应力-应变变化规律。

Research on the Stress-strain Curve of the Concrete Under Cyclic Loading and Unloading

The cyclic loading and unloading tests of the concrete are carried out under different strain rates by large multi-functional static and dynamic triaxial apparatus researched by China Three Gorges University. The envelope curve and common trajectory of cyclic loading and unloading curve of the concrete are of comparative analysis. The result shows that the shapes of common trajectory and envelope are similar to each other. And through the corresponding value between the peak point of envelope and common trajectory, as well as equation of the envelope, the common trajectory can be deduced. Based on the experimental data and understanding of the characteristics of cyclic loading and unloading curves, the changing properties of a single loading and unloading curve are analyzed. Therefore, the mathematical expressions of the stress-strain curve equation are established. It indicates that the law of stress-strain can be described well by the model.