https://hal-insu.archives-ouvertes.fr/insu-02142990/document

2D-ERT monitoring of soil moisture seasonal behaviour in a river levee: A case study

Application of geophysical methods in a dam project: Life cycle perspective and Taiwan experience

Geophysical and geotechnical methods for fluvial levee investigation: A review

This work presents an interesting case-study regarding a big dam monitoring thanks to the deployment of the electrical resistivity tomography (ERT). In particular, we are concerned with the largest rock-fill dam in Europe, i.e., the dam on Sinni river in Basilicata region (Italy), which is one of the main civil strategic infrastructures in Southern Italy. The presence of fractures visible on the hanging waterproof dam has motivated the investigation about the possible water infiltration in the dam. ERT surveys were carried out to detect the inner areas characterized by lower electrical resistivity values as indicators of the undesired presence of water inside the structure. The imaging capability of the ERT investigation was the key to detect and localize the areas of the dam affected by the presence of water. On the basis of ERT results, the managing body of the dam activated other diagnostic tools in view of a proper planning of future restoration works.

Monte Cotugno Dam Monitoring by the Electrical Resistivity Tomography

Le diagnostic et la surveillance des protections contre la submersion sont des enjeux majeurs. Dans le cadre du projet RS2E-OSUNA (Region des Pays de la Loire), cette these y a contribue par des developpements methodologiques centres sur l'imagerie de resistivite electrique (IRE), associee a d'autres methodes geophysiques et a des observations directes (sondes en place). Les developpements ont ete specifiquement appliques a deux sites en conditions reelles : une levee de Loire pres de Saumur et une dune grise sur l'Ile de Noirmoutier. Le premier objectif scientifique de ce travail concernait la caracterisation de la structure interne des milieux etudies. Une approche recente d'IRE, visant a prendre en compte les effets 3D sans accroitre le cout de la methode par rapport a une approche 2D classique, a ete adaptee et testee. Sur la levee, l'approche s'est averee tres efficace. Sur la dune grise, les resultats preliminaires montrent encore des difficultes d'imagerie du milieu naturel. Le second objectif concernait la surveillance, sur differentes echelles temporelles, de l'evolution des proprietes internes du milieu. On a utilise des protocoles d'acquisition optimises et des methodes d'inversion 2D classique. Sur la levee, les evolutions temporelles decrites par IRE sont coherentes avec les mesures directes des parametres d'etats du sol (sondes a demeure). Sur la dune grise, les variations temporelles observees se sont averees de tres faible amplitude du a une geologie tres particuliere. Le travail est conclu par un parallele methodologique entre les deux sites et la proposition de pistes de recherche et d'amelioration des approches developpees.

Développements méthodologiques pour l'imagerie et le suivi temporel par méthodes géoélectriques des structures de protection contre les inondations fluviales ou les submersions marines

This study was aimed at assessing the performance of electrical resistivity tomography (ERT) applied to the investigation of seepage in earth dams through a case study. Several abnormal leaks appeared on the downstream face of an earth dam after the dam was reconstructed to raise the maximum reservoir water level. A study was conducted to investigate the mechanism of the abnormal leakage with the assistance of ERT. Three two-dimensional (2D) ERT survey lines were deployed on the left abutments, dam crest, and downstream shell, respectively. Periodic measurements were additionally collected on the downstream shell for time-lapse measurements. To gain confidence and avoid over interpretation, the results of 2D ERT were appraised by forward modeling and synthetic inversion. Combining ERT results with geotechnical monitoring data clearly indicates the likely mechanism of abnormal seepage. Time-lapse measurements further support the inducted mechanism. Integration of ERT exploration with time-lapse ERT measurements and geotechnical monitoring data was demonstrated to better understand the possible mechanism of the abnormal seepage.

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Investigation of abnormal seepages in an earth dam using resistivity tomography

There is a great demand for effective non-destructive methods to examine the interior of reservoir structures, such as dams. The present study was aimed at assessing the performance of ele...

Zen Hung Yu

Papers

Investigation of abnormal seepages in an earth dam using resistivity tomography

Performance of 2-D ERT in investigation of abnormal seepage: A case study at the Hsin-Shan earth dam in Taiwan