An Innovative Low-Cost SDMT Marine Investigation for the Evaluation of the Liquefaction Potential in the Genova Harbour (Italy)

A new container quay namely "Calata Bettolo", will be built inside the Genova harbour. The length of the quay is of about 750 m and the area is of about 22,000 m2. The depth of water will reach 17 m along the quay. The material to fill the area of the quay derives from the dragging of the bottom of the harbour to increase in some areas the depth of water. Detailed in situ and laboratory tests have been made for site characterisation, to face all geotechnical design aspects of the quay. In this paper will be discussed the in-situ tests for the evaluation of the seismic behaviour of the Calata Bettolo. Among the in situ tests, Seismic Dilatometer Marchetti tests (SDMTs) have been carried out with the aim of general site characterisation, with particular reference to the evaluation of the soil profile of shear waves velocity (Vs) and horizontal stress index Kd for liquefaction potential analysis. The SDMT test program includes tests on the land and on the sea. The latter have been made by an innovative technique by means of floating barge. This technique allowed to perform the SDMT tests at considerably reduced cost in comparison with tests executed from a self elevating platform. The Seismic Dilatometer Marchetti Tests were performed up to a depth of 42 meters. The results show a very detailed and stable shear waves profile. The SDMT test results enable to evaluate the potential liquefaction hazard by two independent measurements, Kd and VS. The results obtained for potential liquefaction by Kd and VS are compared and discussed.