Geoelectric versus MASW for geotechnical studies

Abstract

We explore the role of non-invasive multi-electrode electrical resistivity imaging (ERT) and induced polarisation imaging (IPI) as an alternative to multichannel analysis of surface waves (MASW) for geotechnical site characterisation in view of their higher near-surface spatial resolution. By using regression equations, we assess the relative performance of ERT, IPI and MASW in predicting geotechnical test results (standard penetration test (SPT), dynamic cone penetration test (DCPT) and static cone penetration test (SCPT)) in a site investigation on our IIT Roorkee Campus, India. The results indicate that the average root mean square (RMS) errors in predicting SPT based on ERT, IPI and MASW are 16.95%, 21.9% and 28.03%, respectively. Likewise, the average RMS errors in predicting DCPT based on ERT, IPI and MASW are 15.4%, 15.3% and 56.99%, respectively, and the average RMS errors in predicting SCPT based on ERT, IPI and MASW are 20.15%, 18.65% and 36.49%, respectively. In view of higher resolution for near-surface investigations, ERT/IPI seems to score over MASW in geotechnical site investigation studies. So, a leading role for non-invasive and cost-effective ERT/IPI in geotechnical site investigations is envisaged.