Using resistivity surveying methods for geotechnical study of subsurface properties for foundation design

Abstract

The evaluation of subsurface properties plays a pivotal role in understanding geological formations and assessing their suitability for various engineering and environmental applications. In this work, the subsurface properties of open ground were investigated. Two constant separation traversing (CST) profiles were measured using the Wenner array electrode configuration, with electrode positions ranging from 0 to 150 m depending on the profile, and ten vertical electrical soundings (VESs) were conducted using the Schlumberger array electrode configuration, with half-current electrode separation (AB/2) ranging from 1 to 55 m. The topsoil resistivity ranged from 186.9 to 1222.0 Ω m, with an average of 422.5 Ω m, and its thickness ranged from 0.5 to 1.0 m. The weathered layer showed resistivity values between 13.6 and 70.0 Ω m, with a mean of 29.6 Ω m, thicknesses between 1.4 and 9.9 m, and depths between 1.9 and 10.9 m. These variations in resistivity and layer thickness indicate the presence of weathered and fractured zones that must be taken into account during foundation design.