Characterization of the recent soft silty clay deposit in the Ravenna port area (Italy)

To plan upgrading works of several quays, an extensive geotechnical survey has been carried out includ-ing both in-situ testing as well as laboratory testing. The unusual extent of the investigated area, ranging from coastline to 4 km inland, allowed to appreciate the variation of the stratigraphic arrangement of the deposit related to its deposi-tional history. This paper presents the results of such investigation focusing on the geotechnical properties of the thick, recent, soft silty clay deposit that governs the design of the quay walls. The wide available database and the choices to concentrate in a restricted number of sites several investigations allows to compare properly the results coming from la-boratory and in-situ tests. In particular, due to their implication on fundamental design decision, the attention has been focused on the identification of the soil and on the undrained shear strength. These two aspects, related to the time to develop settlements and short term response to the loads, have been analysed in depth by comparing the results of la-boratory tests on undisturbed samples with the estimation given from CPTu and DMT tests. The results shows that in-situ tests are powerful tools but require care when used to evaluate strength parameters and the association with a lim-ited number of laboratory tests allows to obtain a reliable and cost-effective geotechnical characterization.