International Scholarly Research Network ISRN Civil Engineering Volume 2011, Article ID 378579, 11 pages doi:10.5402/2011/378579 Research Article Site Monitoring and Numerical Modelling of a Trial Embankment’s Behaviour on Venice Lagoon Soils Valentina Berengo, 1 Thomas Benz, 2 Paolo Simonini, 3 and Martino Leoni 4 1 Geotechnics and Structure Department, NET Engineering S.p.A., 35043 Monselice, Italy 2 Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway 3 IMAGE Department, University of Padova, 35129 Padova, Italy 4 Wesi Geotecnica Srl, 54100 Massa, Italy Correspondence should be addressed to Martino Leoni, martino.leoni@wechselwirkung.eu Received 24 May 2011; Accepted 21 June 2011 Academic Editors: Y. Lai and M. T. Tumay Copyright © 2011 Valentina Berengo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Mineralogical and mechanical characterization of Venice lagoon soils is required for design and construction of movable floodgates that aim to safeguard the city of Venice against recurrent floods. An instrumented circular test embankment was constructed in the lagoon area, enabling accurate measurement of relevant ground displacements. In situ stress-strain-time measurements were carried out in order to investigate the viscous behaviour of Venice lagoon soils during and after embankment loading. Site monitoring was kept up also during embankment removal so that information on soil behaviour in unloading is available, too. This paper illustrates key results from embankment monitoring and also focuses on modelling of creep behaviour. A recently developed anisotropic constitutive model was calibrated for Venice lagoon soils and is used in back analysis of the embankment construction and removal process. The constitutive parameters of the model were calibrated from in situ and laboratory tests. 1. Introduction The worldwide-known historic city of Venice and the surrounding lagoon is suffering overall rapid deterioration, caused mainly by an increasing flood frequency due to the eustatic sea level rise, coupled with a natural and man-induced subsidence, the latter particularly significant between 1946 and 1970. The importance of preserving the historic city has, therefore, stimulated the proposal of numerous technical solutions, including movable gates located at the three lagoon inlets (i.e., Malamocco, Chioggia, and Lido) to con- trol water levels within the lagoon. These gates temporarily separate the lagoon from the sea at the occurrence of particularly high tides, which have increased notably and in frequency. Standard geotechnical investigations were, therefore, performed at the inlets, and recently, two test sites were selected, where investigations on the main properties of the Venetian soils have been concentrated. The main characteristic of the lagoon soils is the presence of a predominant silty fraction, combined with clay and/or sand [1]. These form a chaotic interbedding of different sediments, whose basic mineralogical characteristics vary narrowly, as a result of unique geological origins and a common depositional environment. This latter feature, together with the relevant heterogeneity of soil layering, seemed to suggest concentrating the main research efforts on selected test sites, considered as representative of typical soil profiles, where relevant in situ and laboratory investigations could be carried out in the careful characterization of the Venetian lagoon soils. At the first test site, located at the Malamocco inlet, a series of investigations including boreholes, piezocone, dilatometer, pressuremeter, and cross-hole tests were per- formed on contiguous verticals. In addition, a comprehen- sive laboratory characterization was carried out [1]. A second test site, namely, the Treporti test site, was then selected to measure the site stress-strain-time behaviour of Venice lagoon soils. A vertically walled circular embankment,