Applicability of Using the Earth Resistivity in Evaluating of Some Engineering Parameters for Road Subgrade/Naynawa Governorate

The present research includes studying the electrical resistivity and some engineering parameters (plasticity index, California Bearing Ratio, dry density, clay content, moisture content) for the Soil subgrade of the roads. Six sites were selected to conduct the study at Nineveh Governorate in Northern Iraq. Three of them are located to the east of Tigris river while the others to the west of it. Each site contains four locations, each of them includes five traverses with five sounding points in each traverse. The Constant Separation Traversing and Vertical Sounding are employed for delimitating the resistivity parameters, horizontally and vertically, with Wenner deployment. The field data were represented with six isoresistivity sections which indicate lateral and vertical variations reflecting subgrade soil inhomogeneities in the study area. The required laboratory tests are carried out for the recognition of the physical characteristics for soil classification and determination of the engineering parameters. As well, the present study tried determining relationships between electrical resistivity and engineering parameters through the results of the statistical correlation analysis. The study recommended the possibility of using isoresitivity sections in selecting for the proper sites for subgrade soil samples, and subsequently ending the random method in collecting the samples which always used. ) ( . . . . . . . .