基于内聚力模型的新旧混凝土粗糙界面剪切性能仿真分析

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中图分类号：0341;TU528 文献标志码：A 文章编号：1000-4939（2025）06-1375-12

Abstract：The roughness of the interface between new and old concrete is one of the key factors that affect its shear performance.In this paper，the roughness of the new and old concrete interface is characterized and quantified based on fractal theory.Different fractal dimension interfaces of new and old concrete random aggregate geometric models are established using the Monte Carlo method and aggegate grading theory.By simulating the mechanical behavior of rough interfaces using zero-thickness cohesive elements locally embedded in the model，the effects of mesh size，random distribution of aggregates，fractal dimension， normal pressure，and interface material parameters on the shear performance of rough interfaces between new and old concrete are analyzed.The results show that the model's mesh size and random distribution of aggregates have no significant effect on the shear performance of the interface between new and old concrete.As the fractal dimension increases，the interface shear strength first increases and then decreases， and the fractal dimension corresponding to the maximum shear strength decreases as the normal pressure increases.Under the same fractal dimension，the shear strength increases linearly with the normal pressure.The normal pressure has a more significant impact on the interface shear strength compared to the fractal dimension. As the fractal dimension increases，cracks are more likely to propagate deeper into the old concrete area，and increasing the strength and fracture energy of the new and old interface can ffectively improve the shear performance of the interface.

Key words： old and new concrete；cohesive zone model; surface roughness； fractal dimension； shearproperty

在混凝土大坝分层浇筑、危旧房屋翻建改造和桥梁补强加固等实际工程中，需要在旧混凝土表层浇筑新混凝土，这会形成不同粗糙度的新旧混凝土界面。（剩余14261字）