Characterization of Karst Terrain Using Electrical Resistivity Imaging Technique

Due to the unique characteristics of Karst terrain, accurately defining subsurface conditions presents significant challenges. Failure to identify Karst terrain features, such as rock pinnacles and large soil-filled cavities in rock, can significantly increase project cost both during and after construction. Resistivity profiling, also known as Electrical Resistivity Imaging (ERI), is an effective geophysical investigation technology used to identify sinkhole features. Resistivity profiling provides valuable data for engineers to assess sinkhole potential. Its data helps with selection of appropriate foundation types, construction procedures and storm water management practices. The ultimate result of ERI data acquisition is reduction in sinkhole collapse potential and associated impacts to the construction cost and schedule. This paper provides a general description of the ERI technique. In addition, it presents ERI profile data obtained at a karst terrain site in Pennsylvania, in close proximity to geotechnical test boring locations. A comparison study between ERI profile data and standard penetration test borings are also presented. Finally, conclusions are presented regarding the effectiveness of the ERI in site characterization and ERI's limitations.