Correlation of Apparent Electrical Resistivity with Elastic Moduli and Soil Shear Strength Parameters in Yenagoa, Southern Nigeria

Abstract

Many published correlations between soil electrical resistivity with soil strength parameters are limited to site-specific qualitative correlations between geoelectrical and geotechnical data. The absence of site-specific quantitative transforms for resistivity and various geotechnical test results such as CPTu do not allow the prediction of geotechnical parameters via geoelectric data. Thus, establishing a correlation between soil electrical resistivity and soil strength parameters, which can be applied in shallow soil strength prediction, would be a significant advance for engineering practice. In this study, field tests consisting of vertical electrical sounding (VES) and CPTu data acquired at the same location were analyzed and correlated to develop empirical models. At selected depths, we collected the apparent resistivity variation with depth and correlated with the soil strength parameters such as shear modulus, Young’s modulus, bulk modulus, undrained shear strength and friction angle derived from the CPTu data at the same location. Least square regression method was used to evaluate the relation between apparent resistivity and the different soil strength parameters. Linear curve fitting approximations were applied. The results show that apparent electrical resistivity has a good correlation with soil strength parameters with coefficient of correlation ranging between 0.4-0.7. The empirical models were validated by predicting the soil strength parameters. The measured and predicted values show a good correlation and thus affirm the applicability of the proposed empirical models.