Geotechnical characterization and properties of Venice lagoon heterogeneous silts.

To protect the city of Venice against recurrent flooding, a huge project has been undertaken involving the design and construction of movable gates located at the three lagoon inlets for controlling tidal flow. The design of the gate foundations demands accurate geotechnical characterization of the Venice lagoon soils, composed of a predominantly silt fraction combined with clay and/or sand forming an erratic interbedding of various sediments, whose basic mineralogical characteristics vary narrowly. To this end, two typical test sites in the lagoon - the Malamocco Test Site and the Treporti Test Site – were selected for the mechanical soil characterization and for a site-specifically calibration of the most widely used geotechnical investigation tools. Besides a presentation of the main geological features of the lagoon sediments, the paper presents and discusses the main outcome of the research carried out at the Malamocco Test Site and some results from the Treporti Test Site.