多轴应力下塑性混凝土峰值后变形特征

Post Peak Deformation Characteristics of Plastic Concrete under Multiaxial Stress State

通过单轴压缩试验以及侧压恒定和侧向位移恒定的2类真三轴压缩试验,研究了塑性混凝土峰值后变形特征.结果表明:塑性混凝土峰值后变形特征与试验的侧限条件密切相关.塑性混凝土在单轴受压情况下,峰值后变形呈现软化特征;在侧压恒定的真三轴压缩试验下,峰值后变形呈现理想塑化或近似塑化特征,试件的破坏主要表现为双向剪切破坏,且破坏方向与最小主应力方向一致;在侧向位移恒定的真三轴压缩试验下,峰值后变形呈现硬化特征,试件的破坏主要表现为轴向过大的压缩变形.当变形参数D2>0时,峰值后变形表现为硬化;当-0.1≤D2<0时,峰值后变形表现为理想塑化或近似塑化;当D2<-0.1时,峰值后变形表现为软化.

Post peak deformation characteristics of plastic concrete were studied using uniaxial and true triaxial compression tests. The results show that post peak deformation characteristics are greatly influenced by confining conditions. Post peak deformation of plastic concrete becomes softened under uniaxial stress state. It will be ideally plastic or approximately plastic under true triaxial stress state with constant confining pressure, and hardened under true triaxial compression state with constant lateral displacement. The parameter of D2 can distinguish post peak deformation characteristics of plastic concrete. Post peak deformation will be hardened when D2 is positive, and ideally plastic or approximately plastic when D2 is from -0.1 to 0,and softened when D2 is less than -0.1.