The seismic dilatometer (SDMT) is the combination of the standard flat dilatometer (DMT) with a seismic module for measuring the shear wave velocity V_S. This paper summarizes the experience gained from SDMT tests performed at 34 sites. In particular' the paper presents an overview of the SDMT equipment, comparisons of V_S measured by SDMT and by other methods, interrelationships G₀, E_D, M_DMT based on 2000 data points and a selection of significant SDMT results and related comments. The paper also illustrates the major issues of present research on use and applications of the SDMT, mostly focused on the development of methods for deriving the in situ G-γ decay curves and for evaluating the liquefaction resistance of sands based on SDMT results.

This study is part of an extensive research program carried out at the Treporti Test Site (Venice, Italy), where a cylindrical trial embankment was constructed and monitored from the beginning of its construction until complete removal, four years later. This paper concentrates mainly on the evaluation of overconsolidation and stiffness of the Venice lagoon sands and silts. The possibility to estimate OCR in sand by the combined use of SDMT and CPTU is investigated. A tentative correlation for estimating OCR in sand from the ratio MDMT /qt is constructed. Field compression curves have been back-figured from "1-m field oedometer" curves reconstructed from local vertical strains measured by sliding deformeter under the embankment center. SDMT and CPTU soundings performed before embankment application and post-removal have permitted to analyze how the OCR caused by the embankment was reflected by the before-after SDMT and CPTU results. The paper also illustrates the possible use of the SDMT to assess the in situ decay of stiffness with strain level, by comparison with the stiffness decay curves of the elements on the centerline back-figured from the observed embankment behavior under increasing loading

The paper explores the application of conventional (DMT) and seismic (SDMT) dilatometer tests to an important case of deep excavation design. The work presents finite-element analyses simulating a deep excavation close to Barcelona (Spain). A thick layer of soft interbedded sandy and silty soils made characterization based on laboratory testing very difficult. SDMT offered an alternative for estimating the soil stiffness and its stress-strain dependency. Numerical results and high-quality monitoring data show quite close agreement for most phases of the construction process, supporting the use of seismic dilatometer tests in numerical analyses of deep excavations. The paper also indicates the importance of incorporating stiffness data at low strains. FE analyses involved some uncertainties derived from the presence of jet-grouting soil treatments. On this point, a parametric study illustrates the effects of different modeling approaches.