高密度电阻率法检测混凝土缺陷的模型试验研究

Model experimental study of concrete defect detection using high density resistivity method

为利用高密度电阻率法检测混凝土缺陷,在三峡大坝施工现场,用坝体混凝土制成6m×2m×10m的大体积混凝土模型,模型内置各种混凝土质量缺陷。采用高密度电阻率法,测得混凝土内部视电阻率的分布图像。结果表明:图像识别基本上能反映架空和不密实体的空间位置及形状,对垂直裂缝的反映尤其明显,但对于探测尺寸小于0.3m的不密实体,效果较差。探测初浇混凝土的内部均匀性,一般应在混凝土7d初凝、内部各点含水率基本相等后进行。

For adopting high density resistivity method to detect defects of concrete, a physical model dimensioning 6 m×2 m×10 m and containing diverse defects was fabricated in the construction site of the Three Gorges Project. The concrete resistivity distribution image was obtained by the high resistivity metod. It revealed that the positions and forms of defects such as vertical fissures, pouring voids and loose zones in concrete can generally be identified, but the effect is not well as the size of defects is less than 0.3 m. The suitable detecting time for newly poured conerete ought be after 7 d of initial consolidation and the moisture content at every points inside concrete reaching basically the same.