Stress history of Venice Lagoon sands from DMT and CPTU

This paper investigates the possibility to estimate the stress history of the sand deposits of the Venice lagoon by the combined use of DMT and CPTU results. The study is based on an extensive experimental program carried out at the Treporti Test Site, where a cylindrical trial embankment (40 m diameter, 6.7 m height, applied load 106 kPa) was constructed and monitored from beginning of construction until its complete removal, four years later. OCR of the virgin soil (without embankment) was back-figured from “1-m field oedometer” curves reconstructed from local vertical strains measured by sliding deformeter under the embankment center in 1 m-thick layers. OCR at end of construction (OCR = 1) and after embankment removal (OCR > 1) was imparted by mechanical loading-unloading. A tentative correlation between OCR and the ratio MDMT /qt in sand was constructed using parallel DMT and CPTU results obtained at end of construction and after embankment removal, associated to reliable (imparted) OCR values.