Case Study on the effects of physical parameters in electrical resistivity of fine grain soil

Soil electrical resistivity is an easy indicator of soil corrosion potential assessment. In order to investigate the soil corrosion in an industrial zone on the margin of the Meyghan salt lake (Kheyr-Abad industrial town), the electrical resistivity was measured by Miller box in laboratory considering different conditions in terms of moisture content. Soils in the region are generally fine-grained and typically are from clay type (CL/CH) according to USCS. In the minimum considered moisture content for the test, which correspond to the dry season, the soils of the study area have the moderate to the severe corrosive potential that increases to the Meyghan lake side. The corrosion potential pattern in superficial soils (0 to 5 m) follows northeastern to southwest waterway channels and is more homogeneous in the deeper parts (5 to 10 m). With increasing moisture content, the electrical resistivity is strongly reduced and in the moisture content of 25%, the corrosion potential of the soils of the study area increases to severe and very severe. Analysis of covariance and correlation coefficient of resistivity decreasing ratio due to increased moisture content with the basic physical properties of soil indicates that the fine grained material content (passing #200) has the most effect on the decreasing of resistivity. The plasticity index, liquid limit and dry density have minor effects in comparison to fine grained material content.