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International audienceThis paper describes an efficient methodology for the identification of soil parameters using the combination of the finite element method and the in situ pressuremeter test (PMT). The objective of the procedure applied here is to identify the parameters of generalized Prager model associated with the Drucker and Prager failure criterion from a pressuremeter expansion curve. The approach consists of minimizing the function representing the difference between the experimental curve and the curve obtained by integrating the model along the loading path in the in situ testing. First, both analytical expressions governing the problem of cavity expansion and those related to the finite element modeling are given in detail. Then, a Fortran computer program called "Press-Sim" along with the solution strategy are described and clearly explained. The influence of some model parameters as well as the probe geometry on the computed pressuremeter curves is examined. The paper finishes by presenting some identification examples drawn from real experimental tests for which the targeted parameters are compared with those of other experimental procedures. Results of comparison show a very good agreement

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A pseudo-three-dimensional numerical model has been developed for the analysis of full 3D soil problems under combined loading. The procedure called Vertical Slices Model takes advantage of finite element (FE) 2D numerical solutions in plane stress for building approximate 3D solutions by replacing the inter-slice interactions by fictitious body forces. Continuum slices are successively analyzed by the combination of the explicit 2D finite element (FE) method and finite difference (FD) method in iterative process. The three-dimensional aspect of the considered problem is preserved by satisfying the continuity of shear stresses developed at the inter-slices. The theory of the vertical slices model is developed first, and then encoded in a Fortran computer program. Next, the prediction capabilities of this program are illustrated with two classical geotechnical applications, namely; the laterally and the axially loaded single piles embedded in homogeneous and non-homogeneous elastic soils. Although approximate, the model proved its ability to capture the behavior of the two boundary value problems. Then, in terms of stiffness factors the approach is used to predict the behavior of an embedded rigid square footing and a pile under combined loading in a half-space where the stiffness shows a power law variation with depth. Keywords: Finite element analysis; finite difference method; vertical slices; iterative process. 231 Int. J. Comput. Methods 2005.02:231-253. Downloaded from www.worldscientific.com by NANYANG TECHNOLOGICAL UNIVERSITY on 08/24/15. For personal use only. 232 D. A. Bouzid et al.