Investigation of Relationship between Geotechnical Parameters and Electrical Resistivity of Sandy Soils

Subsurface investigation is one of the most critical phases of any construction project. An insufficient subsurface investigation is the primary source of change orders in 20 to 50% of infrastructure projects and may lead to costly failures due to uncertainties during the construction phase. Due to inherent limitations of conventional subsurface investigation methods, characterization of soil physical parameters using quick and non-invasive soil investigation methods (e.g., electrical resistivity) has been of interest to researchers. Developing proper relationships between electrical resistivity and geotechnical parameters helps to characterize the soil parameters at any location/depth. This paper aims to investigate the effects of water content, dry unit weight, fine fraction, and clay fraction on the electrical resistivity of sandy soils and create appropriate models for estimating them based on the electrical resistivity values. The linear regression analyses were performed using 100 observations obtained from laboratory testing (physical property and electrical resistivity tests). The results show a significant relationship between water content, dry unit weight, and clay fraction with electrical resistivity. The results also show that an increase in water content, dry unit weight, and clay fraction results in a decrease in the electrical resistivity. These findings contribute to the body of knowledge by identifying the influencing geotechnical parameters and quantifying the relationships between electrical resistivity and geotechnical parameters of sandy soils. It is expected that this research helps construction engineers and managers to have a rapid and continuous assessment of subsurface characteristics in the field to avoid costly failures.