Cross-street electrical resistivity imaging for environmental applications

Abstract

Road collapse has always been an important safety hazard for urban traffic, causing a serious threat to the safety of passing vehicles and citizens. However, the complex urban surface environment with obstacles such as huge buildings, hardened roads, and river network limits the application of ERT in cities. Here we present an innovative cross-street electrical resistivity imaging method. This method abandons the mandatory electrode grid layout that conventional 3D ERT required. Only two survey lines are required to be laid along sides of the street parallelly, gathering the apparent resistivity data set by the combination of current supply and potential electrodes across the street and obtaining the 3D resistivity imaging under street. It is well suitable for detecting and monitoring of hardened road and enhances the feasibility and the adaptability of ERT in urban. A series of numerical models and comparisons among this method and conventional ERT had been done. The modeling results show that this cross-street method reaches the resolution of the conventional 5-lines ERT, and its resolution to objects cross road are better than the conventional ERT. This method can both satisfy the exploration needs with difficult surface conditions such as roads, and greatly reduce the exploration workload. It shows well application prospects, such as hidden geological problem monitoring while combining with time-lapse ERT instruments.