The Utility Of Multi-Electrode Resistivity Data In Geotechnical Investigations – A Case Study

Abstract

For any major civil engineering construction, traditional geotechnical investigations like, standard penetration test (SPT), dynamic cone penetration test (DCPT) and static cone penetration test (SCPT) are carried out to assess the suitability of a site. These tests provide point information depthwise. However, non-invasive geoelectrical site investigations can provide subsurface resisistivity information in 1-D, 2-D and 3-D scales. Here, through a case study, an effort is made to relate the 2-D resistivity/IP sections to field geotechnical results and extend the scope of geoelectric sections to geotechnical site characterization. The available geotechnical test results like SPT, DCPT and SCPT for a multi-storeyed building in Indo-Gangetic Alluvial Plains are correlated with 2-D resistivity sections gained from two multielectrode resistivity-imaging experiments. The good correlation between SPT and IP sections allowed us to predict synthetic SPT from an interpreted IP section. The actual and synthetic SPT (normalized) match well in phase but differ in amplitude, which means that IP and SPT relationship is non-linear. In future, we hope that by a proper non-linear transformation the limitations of point mode geotechnical tests can be overcome.