压剪共同作用下混凝土的动态力学性能研究

Dynamic Mechanical Properties of Concrete under the Combined Action of Compression and Shear

为了研究混凝土在压剪复合状态下的动态力学性能,采用大型多功能动静力三轴仪进行了5种不同应变速率和5种不同法向应力下的压剪复合受力状态的剪切试验。分析其剪切强度变化规律,构建了基于八面体应力空间二次形式破环准则,转换为正应力与剪应力表示的压剪破环准则形式。结果表明,随着应变速率增加,混凝土的抗剪强度呈增大趋势,而随法向应力的增加,混凝土抗剪强度则呈现出先增大后减小的趋势;基于八面体应力空间二次形式破环准则,建立了考虑速率效应的混凝土压剪破环准则,通过试验数据对比得出该破环准则与试验数据吻合较好。

In order to study the dynamic mechanical properties of concrete under compression-shear combined state,five shear tests under five different strain rates and five different normal stresses were carried out using a large multi-functional dynamic-static triaxial apparatus.The change rule of shear strength was analyzed,and a quadratic criterion of ring breaking based on octahedral stress space was constructed.The criterion was transformed into a compression-shear ring breaking criterion expressed by normal stress and shear stress.The results show that with the increase of strain,the shear strength of concrete tends to increase,while with the increase of normal pressure,the shear strength of concrete tends to increase first and then decrease.Based on the octahedral stress space quadratic form criterion,the compression-shear criterion of concrete considering the rate effect is established.By comparing the test data,the criterion is in good agreement with the test data.