Use of DMT and CPTU to assess the G0 profile in the subsoil

The subject of this article is the analysis of the relationship between G0/MDMT and KD, where G0 is the small strain shear modulus, while MDMT and KD are respectively the constrained modulus and the horizontal stress index determined from DMT tests. This relationship allows to determine a profile with depth of G0 from standard DMT test results, useful when data from non-seismic DMT investigations are available. The analysis was based on a large amount of data for a wide range of soils of different origins in Poland. The dataset included OC and NC loams, silts, medium sands, silty sands and fine sands. The overconsolidation ratio (OCR) was estimated from CPTU and DMT tests. The obtained empirical G0/MDMT vs. KD relationships were compared with the correlations established by Marchetti et al. (2008) for different soil types. To account for the significant influence of overconsolidation, an original empirical relationship between G0/σ’p and KD, where σ’p is the preconsolidation stress, was determined based on data from all investigated fine-grained soils.