Electrical Resistivity Technique (ERT) as a Substitute for Destructive Methods in Soil Exploration

Precise resolution of engineering properties of soil is requisite for absolute design and accomplishing proper establishment of any structure. Geophysical methods are enormously practiced for soil characterization as they are non-intrusive, non-destructive, quick and cost effective. Electrical resistivity(ER) is an appealing technique for characterizing subsurface properties of soil without any disruption. This research confers the outcomes of correlation of ER with soil properties. Different parameters of soil in particular strength parameters like; S.P.T value, Shear Strength (obtained from cohesion(c) and angle of internal friction(Φ) value) along with water content and grain size factor (obtained from percentage of coarse and fine soil) have been correlated with Apparent Resistivity (p_a). Exploration was done upto 9 m at 12 locations around Ludhiana city. Correlations were developed using generalized reduced gradient (GRG) because of non-linear data obtained from sites. The value of electrical resistivity value vary for different locations because of being site specific and also it possesses strong correlations with parameters which were taken into account. The results obtained showed that highest and lowest average value of resistivity were 144.46 Ω-m and 70.15 Ω-m. The formulation of correlation was divided for different ranges of S.P.T value, with variation of observed and calculated S.P.T value not being more or less then 15%. So it can be concluded that Electrical Resistivity technique can provide best suitable and reliable results in soil exploration by involving various geotechnical parameters into account.