Geophysical research applied to the evaluation of percolation conditions of an earth dam

Safety conditions in geotechnical structures require the investigation of the phenomena responsible for the loss of their stability. When combined with commonly used direct investigations, geophysical methods add greater efficiency to geotechnical investigations, since their application allows the acquisition of a large amount of data in a short period of time, and at a relatively low cost. In this context, the present study aimed to evaluate percolation through the massif of a small earth dam, based on an integrated interpretation of results obtained with the application of the geophysical methods of Electroresistivity and Self Potential, in addition to results from geotechnical investigations previously carried out on the structure. The results proved the efficiency of the proposed methodology, allowing the confirmation of hypotheses formulated by other authors in previous studies of the same dam. Also, the results allowed the evaluation of the efficiency of correction works carried out in the dam massif to solve the problems caused by a piping process. Among the identified geotechnical properties, a preferential flow path, which indicates the occurrence of a water loss process through the dam foundation layer, was detected and can be linked to the occurrence of a landslide on the downstream slope of the embankment. It can be concluded that the geophysical survey effectively evaluated the geotechnical conditions and seepage within the massif and its foundations, meeting the study's objectives. Both shallow and deep flow paths in the study area were delineated, pinpointing the factors contributing to their occurrence.