Correlation of Electrical Resistivity of Soil with Geotechnical Parameters (Atterberg Limits) at Gombe, Northern Nigeria
Electrical resistivity technique is a popular alternative method used in geotechnical soil investigations. Most past applications have been particularly in the area of subsurface ground investigations such as to locate boulder, bedrock, water table, etc. Traditionally, this method was performed by a geophysicist expert for data acquisition, processing and interpretation. The anomalies highlighted uncertainties on the nature of soil that was often variable and depended on each particular site
... dition that gave a site dependent soil electrical resistivity value. In order to establish empirical equations that relate layer resistivity values with geotechnical parameters for engineering site characterization, samples collected from four different boreholes drilled to a maximum depth of 40 m meters, samples were collected at 10 m interval which were used in the correlation. Schlumberger array with 300c model of ABEM Terrameter SAS was used in the survey, and later interpreted using WINRESIST2 the interpreted models indicate four layers interpreted as topsoil, weathered sand, silty sand and sandy clay. Atterberg limit test was conducted on the disturbed soil samples. The geo-electrical data and geotechnical parameter were subsequently correlated. The study established that soil electrical resistivity increases with increase in Liquid limit but decreases with increase in plasticity index. Where the correlation coefficients are significant as for plasticity index, the established empirical equations can be used to estimate geotechnical properties from subsoil resistivity values, thereby reducing the cost and duration of engineering site investigation.