Determining G-gamma decay curves in sand from a Seismic Dilatometer Test (SDMT)

Porto de Galinas, Recife, Brazil

This paper investigates the use of the Seismic Dilatometer Test (SDMT) for the determi- nation of in situ decay curves of sand stiffness with strain level (G-γ curves or similar). In situ, laboratory and field data (including footing and self-boring pressuremeter tests) obtained at a silica sand site and a calcareous sand site in Western Australia are used for this investigation. The approach adopted relies on the ability of SDMT to provide a small strain modulus (G from Vs), a “working strain” modulus (G from M tentatively constructed by fitting curves through these three points. The approach is based on the premise that M et al. 2008), while M dilatometer, derived using Lehane & Fahey (2004). The paper illustrates the potential of using the SDMT to obtain in situ G-γ decay curves, but also indicates that additional research is required to improve the 0 DMT ) and an “operational strain” modulus (G from M ). Thus, in situ G-γ decay curves are DMT DV DV is a reasonable estimate of the working strain modulus (e.g. Monaco et al. 2006 and Marchetti is a modulus operating at the settlement ratio s/B of 1.8%, applied by the flat DMT DV reliability of the proposed approach.