基于断裂力学的混凝土结构裂缝分析

Analysis of the Concrete Structure Crack Based on the Fracture Mechanics

混凝土结构在复杂的内外因素综合作用下,构件不可避免的存在裂缝。裂缝是混凝土结构中最常见的一种病害,不仅影响结构承载力和耐久性,而且会增大构件的变形量、削弱截面刚度。通过计算开裂混凝土梁的裂缝尖点处断裂参数应力强度因子和J积分值,运用断裂力学相关知识分析构件裂缝周围的应力状态,研究应力强度因子和J积分与荷载步之间的关系来评定裂缝的稳定性,为混凝土结构安全性和耐久性评定提供依据。

For the complicated internal and external factors, cracks in concrete structure is inevitable, which is one of the most common diseases. It not only affects the bearing capacity and durability, but also will increase the deformation,weaken the section stiffness of the concrete components. Calculated the fracture parameters （the stress intensity factors and J integral value） at crack tip of cracking concrete beam and analyzed the stress state of the component cracks using the knowledge of fracture mechanics, the relationship between the load step and the fracture parameters was studied to assess the stability of the crack. It can provide the basis for the safety and durability evalua- tion of concrete structure.