基于图像统计的带预制缺陷混凝土破坏机理

Failure Mechanism of Precast Defective Concrete Based on Image Statistics

采用计算机断层扫描(CT)、声发射(AE)和数字图像处理(DIP)的建模方法,对含聚苯乙烯泡沫(EPS)颗粒的预制缺陷混凝土单轴加载破坏过程进行研究,分析了内部缺陷对裂缝扩展的影响,揭示裂缝扩展机理,并提出了缺陷混凝土结构细观建模方法.结果表明:裂缝首先出现在混凝土角部及距外部较近的宏观缺陷处,劈裂型裂缝对承载力影响严重,张开型裂缝多出现在水平投影最大的宏观缺陷处;通过CT扫描证实了采用聚苯乙烯泡沫颗粒预制缺陷方法的合理性,建立的模型能够准确描述缺陷混凝土的力学行为,验证了细观模拟与力学试验的一致性.

The uniaxial loading failure process of precast defective concrete containing expanded polystyrene(EPS)particles was investigated by computed tomography(CT),acoustic emission(AE)and digital image processing(DIP)modeling methods.The mechanism of internal defects on crack propagation was revealed by practical mesoscopic modeling methods.The results show that the cracks appear at the corner initially and the defect closer to the outside of the concrete.The bearing capacity is seriously affected by split⁃type cracks.The open cracks often appear at the largest macroscopic defect in the horizontal projection.The rationality of using expanded polystyrene particles as prefabricated defects in the concrete is confirmed by CT scan.The established model can accurately describe the mechanical behavior,which verifies the consistency of meso⁃simulation and mechanical experiment.