Caratterizzazione geofisica di un sistema arginale e applicazioni geotecniche.

The following thesis focuses on the geophysical characterization of a levee system near San Michele al Tagliamento in the province of Venice. The area of study is localized in proximity of the locality San Mauretto where there is an artificial embankment of the Tagliamento river. The research aims at learning experimental methodology of the most common geophysical surveys, using different techniques of data analysis and processing. The present work was carried out on the basis of modern geophysical techniques such as the Electrical Resistivity Tomography (ERT) and the Multichannel Analysis of Surface Waves (MASW method). These investigations are relatively inexpensive and permit to obtain a lot of information in a short time; for this reason, they were performed to identify both the materials which compose the embankment and the soil structure at the same site. The ERT surveys were carried out both on the embankment and on the flood plain between the river and the levee. More precisely, the ERT acquisitions on the embankment consist of eight high resolution lines: four lines were arranged along the top of the levee while the remaining were placed perpendicular to the main axis; the ERT on the flood plain is characterized instead by a wide electrodes spacing (five meters) so it has a lower resolution but it can explore the subsurface to a depth of about thirty meters. The MASW technique was employed only along the main axis of the embankment; in particular, data were acquired both with the ordinary technique and with the Seismic Streamer, a specific tool that allows to drag all the geophones on the ground surface at the same time. The results were used in conjunction with the information resulting from a geognostic survey in order to create a realistic model of the soil, which was subsequently exploited to predict qualitatively the reaction of the embankment to a flood event; for this reason the seepage flow was simulated by creating a finite element numerical model in order to observe the penetration of the flood wave in the embankment. Therefore, different research techniques can work together in achieving a common objective.