DETECTING DESICCATION FISSURES IN ENGINEERING STRUCTURES USING ELECTRICAL METHODS

摘要

Fissures forming in soil due to desiccation act as pathways for unwanted fluid flow. The presence of such fissures are a cause for concern in several fields and can result in failure of flood defenses, as well as act as pathways for contaminant flow and affect irrigation. Detection of these fissures using conventional methods can be hampered by on-site conditions, with vegetation in particular acting to mask fissures on the surface of a structure. Subsurface analysis of any network of fissures is only possible using trenching or sampling, both of which result in damage to the structure in question. Development of non-invasive techniques is required to ensure fissures can be located at the surface and their subsurface characteristics such as depth and interconnection can be analyzed. In recent years several studies have successfully used Electrical Resistivity Tomography (ERT) to monitor such fissure development in laboratory studies. The presented study shows how this technique along with additional Electromagnetic Imaging (EM) can be used on a levee to show zones of Assuring and how small to miniature scale ERT surveys can characterize surface and subsurface interconnection, allowing potential zones of weakness to be identified.