基于颗粒流仿真分析的新疆灌渠混凝土力学破坏特征研究

Study on the failure characteristic of mechanics of concrete in Xinjiang irrigation channel based on particle flow simulation analysis

为探讨新疆灌渠水利设施混凝土主材力学特征,采用颗粒流仿真方法对混凝土模型的设计因素、试验设定因素开展了力学特征分析及细观损伤探讨。粗骨料含量、界面过渡区厚度与混凝土承载应力均为正相关关系,冻融0次时,粗骨料含量每增长10%及过渡区厚度增长0.5 mm,模型强度分别具有平均增幅5.5%、9.9%。骨料含量主要影响在屈服变形阶段,而界面过渡区厚度对模型应力应变影响在初始弹性阶段开始;冻融作用愈大,则混凝土变形趋于延性软化特征。混凝土的失稳破坏从颗粒胶结面开始,集中于界面过渡区,且过渡区厚度愈大,损伤区量值愈低;模型颗粒自身不出现损伤,粗骨料含量愈多,其主裂纹不可见,但较低时主裂纹呈45°。论文可为水利工程中应用颗粒离散元研究混凝土材料力学特征提供参考。

In order to explore the characteristic of mechanics of mainconcretematerials for irrigation and water conservancy facilities in Xinjiang, the particle flow simulation method is used to analyze the mechanical characteristics of the design factors and experimental setting factors of the concrete models and to discuss the mesoscopic damage.There is a positive correlation between the content of coarse aggregate, the thickness of interfacial transition zone and the bearing stress of concrete, When freezing and thawing 0 times, the strength of the model increased by 5.5% and 9.9% on average when the coarse aggregate content increased by 10% and the thickness of the transition layer increased by 0.5mm.The aggregate content mainly affects the yield deformation stage, while the influence of interfacial transition zone thickness on the stress-strain of the model begins at the initial elastic stage;the greater the freezing-thawing action, the concrete deformation tends to be ductile softening.The instability failure of concrete starts from the particle bonding surface and focuses on the interfacial transition zone, and the greater the thickness of transition zone, the lower the damage zone value;the model particles themselves do not appear damage, the more coarse aggregate content, the main crack is not visible, but at the lower level the main crack is 45°. This paper can provide reference for the study on mechanical characteristics of concrete materials by particle discrete element in hydraulic engineering.