压剪共同作用下混凝土的损伤演化研究

利用动静力三轴仪进行不同加载速率不同法向压力下混凝土的抗剪试验，基于Najar能量法的改进，提出一种新的损伤变量计算方法，以此分析法向压力和加载速率对混凝土压剪受力状态下损伤演化的影响；并结合Weibull模型上升段和过镇海模型下降段，构建了压剪损伤模型。研究结果表明:根据提出的计算损伤变量方法的得到结果与混凝土实际受载情况较符合；混凝土压剪受力状态下损伤演化可分为3个阶段:①线弹性阶段；②损伤加速变化阶段；③损伤收敛阶段。法向压力对混凝土的损伤演化有显著的影响，法向压力的增大减缓了混凝土的损伤发展速度；混凝土损伤的发展随着加载速率的增加有滞后的趋势。

Damage evolution study of concrete under joint action of compression and shear

The shear tests of concrete under different loading rates and normal pressures are carried out using a dynamic and static three axis apparatus. Based on the improved Najar energy method, a new calculation method of damage variables is proposed to analyze the influence of normal pressure and loading rate on the damage evolution of concrete under compression shear stress. The compression shear damage model is constructed by combining the ascending section of Weibull model and the decline section of Zhenhai pass model. The results show that the new method of calculating damage variables agrees well with the actual load condition of concrete. The concrete compressive shear stress state under damage evolution can be divided into three stages: the elastic stage; the damage acceleration stage; the damage convergence stage. Normal pressure on the damage evolution of concrete play a significant role. The increase of normal pressure slows down the development of concrete damage, and the development of concrete damage has a trend of lagging behind the increase of loading rate. The constructed shear load deformation full curve damage model agrees well with the experimental data.