大型渠道混凝土衬砌缺陷GPR无损检测研究

根据南水北调东线穿黄南干渠实验段保温板垫层和砂砾垫层混凝土衬砌施工质量探地雷达（GPR）检测结果及室内模拟实验结果,总结了GPR检测图像典型异常特征,确定了渠道衬砌裂缝、混凝土厚度不均、垫层破坏等缺陷对应的异常图谱。并采用正演模拟计算方式分析了GPR方法对裂缝延展深度、混凝土厚度变化、垫层缺陷程度的反映能力。研究表明隐伏裂缝、超过1cm的混凝土厚度变化、垫层破坏程度都可在GPR剖面上得到有效反映。

No Destructive Detecting on Defects in Concrete Channel Lining Using GPR

QDB cushion and gravel cushion concrete lining were two types of lining built in experimental section of South Main Channel crossing Yellow Rive in South-to-North Water Diversion East Line Project. The defects in those channel lining were detected with GPR method and the representative abnormal characteristics of measured GPR image have been pointed. Meanwhile, defects simulation and testing experiment were also carried out in laboratory. Those testing results confirmed the abnormal GPR image characteristic of different lining defects including crack, thickness variation and cushion breakage. Moreover, detecting capability of GPR was also analyzed in this paper with forward calculation method. The forward calculation results showed hidden crack, over one centimeter variation of thickness and break degree of cushion could been figured out in GPR image.