Resumo

AL-FARES, W.  e  ASFAHANI, J.. Evaluation of the leakage origin in Abu Baara earthen dam using electrical resistivity tomography, northwestern Syria. Geofís. Intl [online]. 2018, vol.57, n.4, pp.223-237. ISSN 2954-436X.

An integrated geophysical approach is proposed herewith to identify the potentialleakage zones within the substructure bedrock close to the dam body. Such an approach includes geophysicalsurveys using Electrical Resistivity Tomography (ERT), and traditional VES soundings. Geophysical measurements were carried out at the Abu Baara earth fill dam, located at the southern margins of Al-Ghab plain northwest of Syria. Three long ERT profiles (P1, P2, and P3) were implemented in parallel with the dam embankment in up and down stream reservoir as well as on the dam crest. The acquired geophysical results were interpreted by using different interpretative techniques, particularly the Pichgin and Habibullaev technique one. Three main major blocks, characterizing the geological substructural rocks were distinguished in the surrounding of the studied dam. The alluvial deposits overlaya resistiveand fractured limestone and dolomite bedrock with resistivity values ranging between 300 and 1200 Ωm. Several structural anomalous features were identified within the hard carbonate bedrock. These features are almost related to tectonic elements such as faults, fractures or karstic cavities. The central second block seems to be related to a faulted or subsidence structure coinciding with the main valley, completely filled by alluvial deposits of more than 50m thickness. The detected features represented by faulted structures, fractures and the karstic occurrences, developed within the dam bedrock are therefore regarded as the main responsible causes of the leakage processes from the dam. The integrated geophysical approach presented and proposed in this paper could be easily applied in another similar dams suffering from leakage problems.

Palavras-chave : ERT survey; Pichgin and Habibullaev technique; leakage; Abu Baara earthdam; Syria.

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