Considerations on the Stiffness of Sensitive Soft Soils

The present paper comments on the evaluation of the initial stiffness of sensitive soft soils as an outcome of several testing methods: Resonant Column (RC), Bender Element (BE) tests, Seismic cone tests and Empirical relationships (correlations). The RC, BE and common geotechnical laboratory tests were carried out on soft clays adjacent to the Tunis Lake in Tunisia. The database was completed making use of existing studies carried out on other types of Swedish soft clays from the literature related to seismic cone tests. A number of empirical correlations for determining the initial value of the shear modulus of soils in the literature was adopted in order to re-analyze the available data set. The authors suggested an adapted empirical lower bound correlation aiming at evaluating the analyzed soft soils’ small strain shear modulus (G_max), probably even useful for less undisturbed sampling. The proposed equation aims at giving an indication of the effect of, for example, the mean effective stress (p′) and the corresponding void ratio (e) on the initial soil stiffness more clearly.