Development of a System for Detailed Shallow Electrical Surveys using the Capacitively Coupled Resistivity Technique

We have developed a new capacitively coupled resistivity measurement system to survey the shallow subsurface with high spatial resolution on river levees and other flood defences. The purpose is to assess the risk of piping failure caused by levee foundation leakage. Therefore, it is important to delineate the soil distribution within the shallow subsurface at the toe of the river levee, especially the distribution of permeable sand layers located beneath impermeable clay layers. In this study, we conducted field tests to assess the performance of the newly developed system. A key result was that the new system could detect and image small non-metallic pipes buried near the surface. Furthermore, the resistivity profile obtained by the developed system is in excellent agreement with that obtained by conventional ERT. In conclusion, the new system has the capability to transform levee characterization surveys by delineating the soil distribution at shallow depth with high spatial resolution.