An Experiment of Determining Buried Channel Using ERP and IP

Geophysical methods became an important technique for engineer since several decades. They have been used to study the engineering problem which has to be solved urgently. Detecting underground water channels is one of the most important issues in prevention and mitigation of water surge hazards in underground engineering. In this research, we use electrical resistivity profiling (ERP) and induced potential (IP) as the guide is proposed. By applying different configurations and varied electrode spacing, the water channel can be analysed by its resistivity and chargeability variation. The ERP method is sensitive to resistive layers which indicates the empty channel while IP can detect the presence of water. This is seen from both synthetic and measured data, where the resistivity of 60 Ω.m approximately implies that the channel is not filled with water, while in the area with moderate chargeability, ranging from 15 to 25 ms, indicates that water exists shrouding the channel. By understanding the known underground channel well, we can expand the study for other engineering problems and as references to apply the method in similar cases, such as the underground cavity which can be very important for infrastructure.