大骨料混凝土动态双轴拉压强度试验研究

摘要

To investigate the mechanical properties of concrete under biaxial dynamic stress and different strain rates ,the biaxial dynamic tension-compression tests under different stress ratios and strain rates on the specimens of large aggregate concrete and wet-screened concrete were carried out by using the large-scale triaxial static and dynamic test system .The effects of stress ratio and strain rate on the biaxial tension-compression strength of concrete were studied systematically .The experimental results show that the biaxial tension-compression strengths of the two kinds of concrete are lower than uniaxial tension or uniaxial compression strength . The dynamic strength not only varies with the different stress ratios , but also increases with the increase of the strain rates . Biaxial tension-compression failure criterion of concrete considering stress ratio and strain rate is established in normal stress space ,which can provide experimental basis for the nonlinear analyses of hydraulic structures .%为了研究不同应变速率下混凝土双轴动态受力状态的力学性能 ,在大型静、动态三轴试验机上 ,对大骨料混凝土和湿筛混凝土试件进行了不同应变速率和应力比下的双轴动态拉压试验 ,系统研究了应变速率和应力比对混凝土双轴拉压强度的影响.试验结果表明 :两种混凝土双轴拉压强度均低于单轴拉伸或单轴压缩强度 ,其变化规律不但与应力比有着密切的联系 ,还随应变速率的增大而增大.在主应力空间建立了考虑应变速率和应力比的混凝土双轴拉压破坏准则 ,为水工结构物的非线性分析提供了试验依据.