围压荷载下混凝土静动力强度的细观力学模型

本文从混凝土细观机理出发，采用翼型裂纹模型分析了围压荷载下混凝土内微裂纹扩展、弯折和相互作用直至材料破坏的过程。采用伪面力法计算了考虑相互作用的弯折扩展裂纹应力强度因子，并通过一些简化得到了显式的表达式。在假定混凝土的断裂韧度不随加载速率变化的前提下，分析和计算了不同围压荷载下的混凝土静动力强度，并与试验结果进行比较。结果表明，本文提出的模型能较好地反映围压荷载下混凝土的静动力特性和破坏机理。

Micromechanics model for static and dynamic strength of concrete under confinement

The processes of propagation, kinking of micro cracks in concrete and the interaction among cracks as well as the induced failure are analyzed by using the model describing the wing type crack from the view point of micromechanics. The pseudo-force method is applied to calculate the compressive strength factor of the kinky propagated crack with the effect of interaction among cracks taken into account. On the assumption that the micro fracture toughness of concrete does not vary with strain rate, the static and dynamic strength of concrete under different confinements can be calculated. The comparison of calculation result with experimental data indicates that good agreement is achieved which implies that the model can be used to explain the rate-dependent properties of concrete in multi-axial stress state.