Influence of Compaction on Electrical Resistivity Characteristics of Fine-grained Soil East of Baghdad City, Iraq

Abstract

In geotechnical practice, there is a continuous demand for an efficient method for measuring the soil moisture content and dry unit weight of compacted soils used in a wide range of earthwork constructions. The Electrical Resistivity method has increasingly been used for rapid and non-invasive assessment of some geotechnical properties. This study aims to evaluate the influence of Moisture Content (MC), Dry Unit Weight (DUW), and Compaction Energy (E) on the Electrical Resistivity (ER) of soil collected from the east of Baghdad City, Iraq. To achieve this goal, soil specimens were compacted to various MC and DUW found in geotechnical practice using different E levels. The ER of prepared specimens was measured using the two electrodes method and compared with various geotechnical parameters related to the compaction process. The results showed that the employed MC, DUW, and E levels influenced the ER. The higher the MC, DUW, and E, the lower the ER. However, the ER was more sensitive to these variables for specimens compacted dry of the optimum. Furthermore, the ER was correlated very well with Volumetric Moisture Content ϴ and Degree of Saturation Sr of soil, with a high correlation coefficient (R2 >94%) and very low p-values, which indicated that these correlations were statistically significant. The current findings indicate the usefulness of the ER method for predicting these parameters. Therefore, using the ER method as a rapid and cost-effective technique for the preliminary evaluation of soil compaction variables in earthwork constructions is recommended. However, the current laboratory findings must be confirmed on different soil types.