The deformation parameters of a soft lacustrine deposit, with vertical sand drains, are evaluated by means of field measurements obtained during and after the construction of a railway embankment. The geotechnical system, modelled as linearly elastic and in plane strain, is analyzed by means of the finite element method and the estimation problem is solved adopting a Bayesian approach. The experimental data, the a priori estimation of the parameters and their uncertainties are considered in the back-analysis. The results provide the optimal values of the parameters, a measure of their uncertainties and, consequently, an index of the effectiveness of the field measurement program
