Undrained strength of clays derived from pressuremeter tests

The behaviour of saturated clays under undrained conditions around pressuremeter path is studied by means of a theoretical and a numerical analysis based on the generalised elastoplastic Prager's model with the Von Mises Criterion which is suitable for these cases of soils and gives a realistic response when unloading is considered. The soil constitutive model is described depending only on three parameters. The model response on pressuremeter path and its identification from experimental data lead to the determination of the undrained cohesion and the initial Young modulus of clays. Comparisons between the undrained cohesions determined with the proposed method and those obtained by other means illustrate the applicability of the method. An application to predict the bearing capacity and the settlement of bored piles using parameters derived from the proposed approach is also presented with a comparison to the measured data.