Applicability of GPR technique for earthen dam failures

Abstract

A dam is a structure constructed across a river or stream to store water upstream from the obstruction. Dams are susceptible to damage for various reasons, which can lead to many catastrophic disasters. Therefore, identifying the dam's structural failures prior to a disaster is crucial. Drilling can be used for dam failure identification. But it is costly and destructive. Integrated geophysical methods have always helped in identifying subsurface features. In the current investigation, the applicability of ground penetrating radar (GPR) to detect potential failures in earthen dams was assessed. The Uyanwatta Lake earthen dam was selected as the study area during this investigation, considering the reported water leakage in this dam. A GPR survey was conducted with 100 MHz and 300 MHz antennas along five survey paths. Those are the top of the dam, 1.5 m below the top of the dam, and three distinct paths for the lake's spill. During the interpretation process, clay layers, fractured zones, gravel layers, and water seepage areas were identified. Those water leakage areas indicate that there has been a leak in the dam. Those results were compared with exploratory drill hole data from the Uyanwatta Lake Dam. Drill hole data has only presented information about the rock types present in the dam. But GPR data was able to provide information on loose sediments in the shallow depths of the dam as well. That indicates GPR data has the potential to provide additional information related to earthen dams.