静载历史下的损伤对混凝土动态抗压性能影响研究

Research on the Dynamic Compressive Performance of Concrete due to the Damage Static Load History

为研究正在使用状态下且已存在初始损伤的混凝土构筑物受冲击动力荷载下的动态力学特性,本文以混凝土试件为试验对象,先通过YAD-2000试验压力机对多组混凝土试件进行预加载,使C30混凝土试件出现不同程度的损伤,然后利用SHPB试验设备对试件进行单次冲击压缩试验,研究静载下的损伤对混凝土应力–应变曲线特征、动态抗压强度、破坏模式等特性的影响.通过系列试验发现,经历初始静载的混凝土表现出较强的损伤效应和应变率效应.静载作用下混凝土的损伤对动态抗压强度降低影响关系中,存在一个分界点.大于分界值时,损伤程度变化对混凝土动态抗压强度影响显著.研究结果对于荷载历史混凝土的动态性能研究和应用具有理论意义和参考价值.

To study the dynamic mechanical properties of concrete structures in service and with initial damage under impact dynamic load,concrete specimens were taken as experimental objects.First,several groups of concrete specimens were preloaded by YAD-2000 test press to varying degrees of damage.Then,the SHPB test equipment was used to perform a single impact compression test on the specimen to study the characteristics of the damage to the concrete stress-strain curve under static load,and influences of characteristics such as dynamic compressive strength and failure mode.Through a series of tests,it was found that the concrete subjected to the initial static load had a strong load damage effect and strain rate effect.There was a boundary point in the relationship between the damage of concrete under static load to the reduction of dynamic compressive strength.When it was greater than the cut-off value,the change in damage degree had a significant effect on the dynamic compressive strength of concrete.The research results have theoretical significance and reference value for the research and application of the dynamic performance of concrete under load history.